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/* Tree based points-to analysis
Copyright (C) 2005-2022 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dberlin@dberlin.org>
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "rtl.h"
#include "tree.h"
#include "gimple.h"
#include "alloc-pool.h"
#include "tree-pass.h"
#include "ssa.h"
#include "cgraph.h"
#include "tree-pretty-print.h"
#include "diagnostic-core.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "stmt.h"
#include "gimple-iterator.h"
#include "tree-into-ssa.h"
#include "tree-dfa.h"
#include "gimple-walk.h"
#include "varasm.h"
#include "stringpool.h"
#include "attribs.h"
#include "tree-ssa.h"
#include "tree-cfg.h"
#include "gimple-range.h"
#include "ipa-modref-tree.h"
#include "ipa-modref.h"
#include "attr-fnspec.h"
/* The idea behind this analyzer is to generate set constraints from the
program, then solve the resulting constraints in order to generate the
points-to sets.
Set constraints are a way of modeling program analysis problems that
involve sets. They consist of an inclusion constraint language,
describing the variables (each variable is a set) and operations that
are involved on the variables, and a set of rules that derive facts
from these operations. To solve a system of set constraints, you derive
all possible facts under the rules, which gives you the correct sets
as a consequence.
See "Efficient Field-sensitive pointer analysis for C" by "David
J. Pearce and Paul H. J. Kelly and Chris Hankin", at
http://citeseer.ist.psu.edu/pearce04efficient.html
Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
of C Code in a Second" by "Nevin Heintze and Olivier Tardieu" at
http://citeseer.ist.psu.edu/heintze01ultrafast.html
There are three types of real constraint expressions, DEREF,
ADDRESSOF, and SCALAR. Each constraint expression consists
of a constraint type, a variable, and an offset.
SCALAR is a constraint expression type used to represent x, whether
it appears on the LHS or the RHS of a statement.
DEREF is a constraint expression type used to represent *x, whether
it appears on the LHS or the RHS of a statement.
ADDRESSOF is a constraint expression used to represent &x, whether
it appears on the LHS or the RHS of a statement.
Each pointer variable in the program is assigned an integer id, and
each field of a structure variable is assigned an integer id as well.
Structure variables are linked to their list of fields through a "next
field" in each variable that points to the next field in offset
order.
Each variable for a structure field has
1. "size", that tells the size in bits of that field.
2. "fullsize", that tells the size in bits of the entire structure.
3. "offset", that tells the offset in bits from the beginning of the
structure to this field.
Thus,
struct f
{
int a;
int b;
} foo;
int *bar;
looks like
foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
bar -> id 3, size 32, offset 0, fullsize 32, next NULL
In order to solve the system of set constraints, the following is
done:
1. Each constraint variable x has a solution set associated with it,
Sol(x).
2. Constraints are separated into direct, copy, and complex.
Direct constraints are ADDRESSOF constraints that require no extra
processing, such as P = &Q
Copy constraints are those of the form P = Q.
Complex constraints are all the constraints involving dereferences
and offsets (including offsetted copies).
3. All direct constraints of the form P = &Q are processed, such
that Q is added to Sol(P)
4. All complex constraints for a given constraint variable are stored in a
linked list attached to that variable's node.
5. A directed graph is built out of the copy constraints. Each
constraint variable is a node in the graph, and an edge from
Q to P is added for each copy constraint of the form P = Q
6. The graph is then walked, and solution sets are
propagated along the copy edges, such that an edge from Q to P
causes Sol(P) <- Sol(P) union Sol(Q).
7. As we visit each node, all complex constraints associated with
that node are processed by adding appropriate copy edges to the graph, or the
appropriate variables to the solution set.
8. The process of walking the graph is iterated until no solution
sets change.
Prior to walking the graph in steps 6 and 7, We perform static
cycle elimination on the constraint graph, as well
as off-line variable substitution.
TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
on and turned into anything), but isn't. You can just see what offset
inside the pointed-to struct it's going to access.
TODO: Constant bounded arrays can be handled as if they were structs of the
same number of elements.
TODO: Modeling heap and incoming pointers becomes much better if we
add fields to them as we discover them, which we could do.
TODO: We could handle unions, but to be honest, it's probably not
worth the pain or slowdown. */
/* IPA-PTA optimizations possible.
When the indirect function called is ANYTHING we can add disambiguation
based on the function signatures (or simply the parameter count which
is the varinfo size). We also do not need to consider functions that
do not have their address taken.
The is_global_var bit which marks escape points is overly conservative
in IPA mode. Split it to is_escape_point and is_global_var - only
externally visible globals are escape points in IPA mode.
There is now is_ipa_escape_point but this is only used in a few
selected places.
The way we introduce DECL_PT_UID to avoid fixing up all points-to
sets in the translation unit when we copy a DECL during inlining
pessimizes precision. The advantage is that the DECL_PT_UID keeps
compile-time and memory usage overhead low - the points-to sets
do not grow or get unshared as they would during a fixup phase.
An alternative solution is to delay IPA PTA until after all
inlining transformations have been applied.
The way we propagate clobber/use information isn't optimized.
It should use a new complex constraint that properly filters
out local variables of the callee (though that would make
the sets invalid after inlining). OTOH we might as well
admit defeat to WHOPR and simply do all the clobber/use analysis
and propagation after PTA finished but before we threw away
points-to information for memory variables. WHOPR and PTA
do not play along well anyway - the whole constraint solving
would need to be done in WPA phase and it will be very interesting
to apply the results to local SSA names during LTRANS phase.
We probably should compute a per-function unit-ESCAPE solution
propagating it simply like the clobber / uses solutions. The
solution can go alongside the non-IPA escaped solution and be
used to query which vars escape the unit through a function.
This is also required to make the escaped-HEAP trick work in IPA mode.
We never put function decls in points-to sets so we do not
keep the set of called functions for indirect calls.
And probably more. */
static bool use_field_sensitive = true;
static int in_ipa_mode = 0;
/* Used for predecessor bitmaps. */
static bitmap_obstack predbitmap_obstack;
/* Used for points-to sets. */
static bitmap_obstack pta_obstack;
/* Used for oldsolution members of variables. */
static bitmap_obstack oldpta_obstack;
/* Used for per-solver-iteration bitmaps. */
static bitmap_obstack iteration_obstack;
static unsigned int create_variable_info_for (tree, const char *, bool);
typedef struct constraint_graph *constraint_graph_t;
static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
struct constraint;
typedef struct constraint *constraint_t;
#define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
if (a) \
EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
static struct constraint_stats
{
unsigned int total_vars;
unsigned int nonpointer_vars;
unsigned int unified_vars_static;
unsigned int unified_vars_dynamic;
unsigned int iterations;
unsigned int num_edges;
unsigned int num_implicit_edges;
unsigned int points_to_sets_created;
} stats;
struct variable_info
{
/* ID of this variable */
unsigned int id;
/* True if this is a variable created by the constraint analysis, such as
heap variables and constraints we had to break up. */
unsigned int is_artificial_var : 1;
/* True if this is a special variable whose solution set should not be
changed. */
unsigned int is_special_var : 1;
/* True for variables whose size is not known or variable. */
unsigned int is_unknown_size_var : 1;
/* True for (sub-)fields that represent a whole variable. */
unsigned int is_full_var : 1;
/* True if this is a heap variable. */
unsigned int is_heap_var : 1;
/* True if this is a register variable. */
unsigned int is_reg_var : 1;
/* True if this field may contain pointers. */
unsigned int may_have_pointers : 1;
/* True if this field has only restrict qualified pointers. */
unsigned int only_restrict_pointers : 1;
/* True if this represents a heap var created for a restrict qualified
pointer. */
unsigned int is_restrict_var : 1;
/* True if this represents a global variable. */
unsigned int is_global_var : 1;
/* True if this represents a module escape point for IPA analysis. */
unsigned int is_ipa_escape_point : 1;
/* True if this represents a IPA function info. */
unsigned int is_fn_info : 1;
/* True if this appears as RHS in a ADDRESSOF constraint. */
unsigned int address_taken : 1;
/* ??? Store somewhere better. */
unsigned short ruid;
/* The ID of the variable for the next field in this structure
or zero for the last field in this structure. */
unsigned next;
/* The ID of the variable for the first field in this structure. */
unsigned head;
/* Offset of this variable, in bits, from the base variable */
unsigned HOST_WIDE_INT offset;
/* Size of the variable, in bits. */
unsigned HOST_WIDE_INT size;
/* Full size of the base variable, in bits. */
unsigned HOST_WIDE_INT fullsize;
/* In IPA mode the shadow UID in case the variable needs to be duplicated in
the final points-to solution because it reaches its containing
function recursively. Zero if none is needed. */
unsigned int shadow_var_uid;
/* Name of this variable */
const char *name;
/* Tree that this variable is associated with. */
tree decl;
/* Points-to set for this variable. */
bitmap solution;
/* Old points-to set for this variable. */
bitmap oldsolution;
};
typedef struct variable_info *varinfo_t;
static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
unsigned HOST_WIDE_INT);
static varinfo_t lookup_vi_for_tree (tree);
static inline bool type_can_have_subvars (const_tree);
static void make_param_constraints (varinfo_t);
/* Pool of variable info structures. */
static object_allocator<variable_info> variable_info_pool
("Variable info pool");
/* Map varinfo to final pt_solution. */
static hash_map<varinfo_t, pt_solution *> *final_solutions;
struct obstack final_solutions_obstack;
/* Table of variable info structures for constraint variables.
Indexed directly by variable info id. */
static vec<varinfo_t> varmap;
/* Return the varmap element N */
static inline varinfo_t
get_varinfo (unsigned int n)
{
return varmap[n];
}
/* Return the next variable in the list of sub-variables of VI
or NULL if VI is the last sub-variable. */
static inline varinfo_t
vi_next (varinfo_t vi)
{
return get_varinfo (vi->next);
}
/* Static IDs for the special variables. Variable ID zero is unused
and used as terminator for the sub-variable chain. */
enum { nothing_id = 1, anything_id = 2, string_id = 3,
escaped_id = 4, nonlocal_id = 5,
storedanything_id = 6, integer_id = 7 };
/* Return a new variable info structure consisting for a variable
named NAME, and using constraint graph node NODE. Append it
to the vector of variable info structures. */
static varinfo_t
new_var_info (tree t, const char *name, bool add_id)
{
unsigned index = varmap.length ();
varinfo_t ret = variable_info_pool.allocate ();
if (dump_file && add_id)
{
char *tempname = xasprintf ("%s(%d)", name, index);
name = ggc_strdup (tempname);
free (tempname);
}
ret->id = index;
ret->name = name;
ret->decl = t;
/* Vars without decl are artificial and do not have sub-variables. */
ret->is_artificial_var = (t == NULL_TREE);
ret->is_special_var = false;
ret->is_unknown_size_var = false;
ret->is_full_var = (t == NULL_TREE);
ret->is_heap_var = false;
ret->may_have_pointers = true;
ret->only_restrict_pointers = false;
ret->is_restrict_var = false;
ret->ruid = 0;
ret->is_global_var = (t == NULL_TREE);
ret->is_ipa_escape_point = false;
ret->is_fn_info = false;
ret->address_taken = false;
if (t && DECL_P (t))
ret->is_global_var = (is_global_var (t)
/* We have to treat even local register variables
as escape points. */
|| (VAR_P (t) && DECL_HARD_REGISTER (t)));
ret->is_reg_var = (t && TREE_CODE (t) == SSA_NAME);
ret->solution = BITMAP_ALLOC (&pta_obstack);
ret->oldsolution = NULL;
ret->next = 0;
ret->shadow_var_uid = 0;
ret->head = ret->id;
stats.total_vars++;
varmap.safe_push (ret);
return ret;
}
/* A map mapping call statements to per-stmt variables for uses
and clobbers specific to the call. */
static hash_map<gimple *, varinfo_t> *call_stmt_vars;
/* Lookup or create the variable for the call statement CALL. */
static varinfo_t
get_call_vi (gcall *call)
{
varinfo_t vi, vi2;
bool existed;
varinfo_t *slot_p = &call_stmt_vars->get_or_insert (call, &existed);
if (existed)
return *slot_p;
vi = new_var_info (NULL_TREE, "CALLUSED", true);
vi->offset = 0;
vi->size = 1;
vi->fullsize = 2;
vi->is_full_var = true;
vi->is_reg_var = true;
vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED", true);
vi2->offset = 1;
vi2->size = 1;
vi2->fullsize = 2;
vi2->is_full_var = true;
vi2->is_reg_var = true;
vi->next = vi2->id;
*slot_p = vi;
return vi;
}
/* Lookup the variable for the call statement CALL representing
the uses. Returns NULL if there is nothing special about this call. */
static varinfo_t
lookup_call_use_vi (gcall *call)
{
varinfo_t *slot_p = call_stmt_vars->get (call);
if (slot_p)
return *slot_p;
return NULL;
}
/* Lookup the variable for the call statement CALL representing
the clobbers. Returns NULL if there is nothing special about this call. */
static varinfo_t
lookup_call_clobber_vi (gcall *call)
{
varinfo_t uses = lookup_call_use_vi (call);
if (!uses)
return NULL;
return vi_next (uses);
}
/* Lookup or create the variable for the call statement CALL representing
the uses. */
static varinfo_t
get_call_use_vi (gcall *call)
{
return get_call_vi (call);
}
/* Lookup or create the variable for the call statement CALL representing
the clobbers. */
static varinfo_t ATTRIBUTE_UNUSED
get_call_clobber_vi (gcall *call)
{
return vi_next (get_call_vi (call));
}
enum constraint_expr_type {SCALAR, DEREF, ADDRESSOF};
/* An expression that appears in a constraint. */
struct constraint_expr
{
/* Constraint type. */
constraint_expr_type type;
/* Variable we are referring to in the constraint. */
unsigned int var;
/* Offset, in bits, of this constraint from the beginning of
variables it ends up referring to.
IOW, in a deref constraint, we would deref, get the result set,
then add OFFSET to each member. */
HOST_WIDE_INT offset;
};
/* Use 0x8000... as special unknown offset. */
#define UNKNOWN_OFFSET HOST_WIDE_INT_MIN
typedef struct constraint_expr ce_s;
static void get_constraint_for_1 (tree, vec<ce_s> *, bool, bool);
static void get_constraint_for (tree, vec<ce_s> *);
static void get_constraint_for_rhs (tree, vec<ce_s> *);
static void do_deref (vec<ce_s> *);
/* Our set constraints are made up of two constraint expressions, one
LHS, and one RHS.
As described in the introduction, our set constraints each represent an
operation between set valued variables.
*/
struct constraint
{
struct constraint_expr lhs;
struct constraint_expr rhs;
};
/* List of constraints that we use to build the constraint graph from. */
static vec<constraint_t> constraints;
static object_allocator<constraint> constraint_pool ("Constraint pool");
/* The constraint graph is represented as an array of bitmaps
containing successor nodes. */
struct constraint_graph
{
/* Size of this graph, which may be different than the number of
nodes in the variable map. */
unsigned int size;
/* Explicit successors of each node. */
bitmap *succs;
/* Implicit predecessors of each node (Used for variable
substitution). */
bitmap *implicit_preds;
/* Explicit predecessors of each node (Used for variable substitution). */
bitmap *preds;
/* Indirect cycle representatives, or -1 if the node has no indirect
cycles. */
int *indirect_cycles;
/* Representative node for a node. rep[a] == a unless the node has
been unified. */
unsigned int *rep;
/* Equivalence class representative for a label. This is used for
variable substitution. */
int *eq_rep;
/* Pointer equivalence label for a node. All nodes with the same
pointer equivalence label can be unified together at some point
(either during constraint optimization or after the constraint
graph is built). */
unsigned int *pe;
/* Pointer equivalence representative for a label. This is used to
handle nodes that are pointer equivalent but not location
equivalent. We can unite these once the addressof constraints
are transformed into initial points-to sets. */
int *pe_rep;
/* Pointer equivalence label for each node, used during variable
substitution. */
unsigned int *pointer_label;
/* Location equivalence label for each node, used during location
equivalence finding. */
unsigned int *loc_label;
/* Pointed-by set for each node, used during location equivalence
finding. This is pointed-by rather than pointed-to, because it
is constructed using the predecessor graph. */
bitmap *pointed_by;
/* Points to sets for pointer equivalence. This is *not* the actual
points-to sets for nodes. */
bitmap *points_to;
/* Bitmap of nodes where the bit is set if the node is a direct
node. Used for variable substitution. */
sbitmap direct_nodes;
/* Bitmap of nodes where the bit is set if the node is address
taken. Used for variable substitution. */
bitmap address_taken;
/* Vector of complex constraints for each graph node. Complex
constraints are those involving dereferences or offsets that are
not 0. */
vec<constraint_t> *complex;
};
static constraint_graph_t graph;
/* During variable substitution and the offline version of indirect
cycle finding, we create nodes to represent dereferences and
address taken constraints. These represent where these start and
end. */
#define FIRST_REF_NODE (varmap).length ()
#define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
/* Return the representative node for NODE, if NODE has been unioned
with another NODE.
This function performs path compression along the way to finding
the representative. */
static unsigned int
find (unsigned int node)
{
gcc_checking_assert (node < graph->size);
if (graph->rep[node] != node)
return graph->rep[node] = find (graph->rep[node]);
return node;
}
/* Union the TO and FROM nodes to the TO nodes.
Note that at some point in the future, we may want to do
union-by-rank, in which case we are going to have to return the
node we unified to. */
static bool
unite (unsigned int to, unsigned int from)
{
gcc_checking_assert (to < graph->size && from < graph->size);
if (to != from && graph->rep[from] != to)
{
graph->rep[from] = to;
return true;
}
return false;
}
/* Create a new constraint consisting of LHS and RHS expressions. */
static constraint_t
new_constraint (const struct constraint_expr lhs,
const struct constraint_expr rhs)
{
constraint_t ret = constraint_pool.allocate ();
ret->lhs = lhs;
ret->rhs = rhs;
return ret;
}
/* Print out constraint C to FILE. */
static void
dump_constraint (FILE *file, constraint_t c)
{
if (c->lhs.type == ADDRESSOF)
fprintf (file, "&");
else if (c->lhs.type == DEREF)
fprintf (file, "*");
if (dump_file)
fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
else
fprintf (file, "V%d", c->lhs.var);
if (c->lhs.offset == UNKNOWN_OFFSET)
fprintf (file, " + UNKNOWN");
else if (c->lhs.offset != 0)
fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
fprintf (file, " = ");
if (c->rhs.type == ADDRESSOF)
fprintf (file, "&");
else if (c->rhs.type == DEREF)
fprintf (file, "*");
if (dump_file)
fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
else
fprintf (file, "V%d", c->rhs.var);
if (c->rhs.offset == UNKNOWN_OFFSET)
fprintf (file, " + UNKNOWN");
else if (c->rhs.offset != 0)
fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
}
void debug_constraint (constraint_t);
void debug_constraints (void);
void debug_constraint_graph (void);
void debug_solution_for_var (unsigned int);
void debug_sa_points_to_info (void);
void debug_varinfo (varinfo_t);
void debug_varmap (void);
/* Print out constraint C to stderr. */
DEBUG_FUNCTION void
debug_constraint (constraint_t c)
{
dump_constraint (stderr, c);
fprintf (stderr, "\n");
}
/* Print out all constraints to FILE */
static void
dump_constraints (FILE *file, int from)
{
int i;
constraint_t c;
for (i = from; constraints.iterate (i, &c); i++)
if (c)
{
dump_constraint (file, c);
fprintf (file, "\n");
}
}
/* Print out all constraints to stderr. */
DEBUG_FUNCTION void
debug_constraints (void)
{
dump_constraints (stderr, 0);
}
/* Print the constraint graph in dot format. */
static void
dump_constraint_graph (FILE *file)
{
unsigned int i;
/* Only print the graph if it has already been initialized: */
if (!graph)
return;
/* Prints the header of the dot file: */
fprintf (file, "strict digraph {\n");
fprintf (file, " node [\n shape = box\n ]\n");
fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
fprintf (file, "\n // List of nodes and complex constraints in "
"the constraint graph:\n");
/* The next lines print the nodes in the graph together with the
complex constraints attached to them. */
for (i = 1; i < graph->size; i++)
{
if (i == FIRST_REF_NODE)
continue;
if (find (i) != i)
continue;
if (i < FIRST_REF_NODE)
fprintf (file, "\"%s\"", get_varinfo (i)->name);
else
fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
if (graph->complex[i].exists ())
{
unsigned j;
constraint_t c;
fprintf (file, " [label=\"\\N\\n");
for (j = 0; graph->complex[i].iterate (j, &c); ++j)
{
dump_constraint (file, c);
fprintf (file, "\\l");
}
fprintf (file, "\"]");
}
fprintf (file, ";\n");
}
/* Go over the edges. */
fprintf (file, "\n // Edges in the constraint graph:\n");
for (i = 1; i < graph->size; i++)
{
unsigned j;
bitmap_iterator bi;
if (find (i) != i)
continue;
EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 0, j, bi)
{
unsigned to = find (j);
if (i == to)
continue;
if (i < FIRST_REF_NODE)
fprintf (file, "\"%s\"", get_varinfo (i)->name);
else
fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
fprintf (file, " -> ");
if (to < FIRST_REF_NODE)
fprintf (file, "\"%s\"", get_varinfo (to)->name);
else
fprintf (file, "\"*%s\"", get_varinfo (to - FIRST_REF_NODE)->name);
fprintf (file, ";\n");
}
}
/* Prints the tail of the dot file. */
fprintf (file, "}\n");
}
/* Print out the constraint graph to stderr. */
DEBUG_FUNCTION void
debug_constraint_graph (void)
{
dump_constraint_graph (stderr);
}
/* SOLVER FUNCTIONS
The solver is a simple worklist solver, that works on the following
algorithm:
sbitmap changed_nodes = all zeroes;
changed_count = 0;
For each node that is not already collapsed:
changed_count++;
set bit in changed nodes
while (changed_count > 0)
{
compute topological ordering for constraint graph
find and collapse cycles in the constraint graph (updating
changed if necessary)
for each node (n) in the graph in topological order:
changed_count--;
Process each complex constraint associated with the node,
updating changed if necessary.
For each outgoing edge from n, propagate the solution from n to
the destination of the edge, updating changed as necessary.
} */
/* Return true if two constraint expressions A and B are equal. */
static bool
constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
{
return a.type == b.type && a.var == b.var && a.offset == b.offset;
}
/* Return true if constraint expression A is less than constraint expression
B. This is just arbitrary, but consistent, in order to give them an
ordering. */
static bool
constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
{
if (a.type == b.type)
{
if (a.var == b.var)
return a.offset < b.offset;
else
return a.var < b.var;
}
else
return a.type < b.type;
}
/* Return true if constraint A is less than constraint B. This is just
arbitrary, but consistent, in order to give them an ordering. */
static bool
constraint_less (const constraint_t &a, const constraint_t &b)
{
if (constraint_expr_less (a->lhs, b->lhs))
return true;
else if (constraint_expr_less (b->lhs, a->lhs))
return false;
else
return constraint_expr_less (a->rhs, b->rhs);
}
/* Return true if two constraints A and B are equal. */
static bool
constraint_equal (struct constraint a, struct constraint b)
{
return constraint_expr_equal (a.lhs, b.lhs)
&& constraint_expr_equal (a.rhs, b.rhs);
}
/* Find a constraint LOOKFOR in the sorted constraint vector VEC */
static constraint_t
constraint_vec_find (vec<constraint_t> vec,
struct constraint lookfor)
{
unsigned int place;
constraint_t found;
if (!vec.exists ())
return NULL;
place = vec.lower_bound (&lookfor, constraint_less);
if (place >= vec.length ())
return NULL;
found = vec[place];
if (!constraint_equal (*found, lookfor))
return NULL;
return found;
}
/* Union two constraint vectors, TO and FROM. Put the result in TO.
Returns true of TO set is changed. */
static bool
constraint_set_union (vec<constraint_t> *to,
vec<constraint_t> *from)
{
int i;
constraint_t c;
bool any_change = false;
FOR_EACH_VEC_ELT (*from, i, c)
{
if (constraint_vec_find (*to, *c) == NULL)
{
unsigned int place = to->lower_bound (c, constraint_less);
to->safe_insert (place, c);
any_change = true;
}
}
return any_change;
}
/* Expands the solution in SET to all sub-fields of variables included. */
static bitmap
solution_set_expand (bitmap set, bitmap *expanded)
{
bitmap_iterator bi;
unsigned j;
if (*expanded)
return *expanded;
*expanded = BITMAP_ALLOC (&iteration_obstack);
/* In a first pass expand to the head of the variables we need to
add all sub-fields off. This avoids quadratic behavior. */
EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
{
varinfo_t v = get_varinfo (j);
if (v->is_artificial_var
|| v->is_full_var)
continue;
bitmap_set_bit (*expanded, v->head);
}
/* In the second pass now expand all head variables with subfields. */
EXECUTE_IF_SET_IN_BITMAP (*expanded, 0, j, bi)
{
varinfo_t v = get_varinfo (j);
if (v->head != j)
continue;
for (v = vi_next (v); v != NULL; v = vi_next (v))
bitmap_set_bit (*expanded, v->id);
}
/* And finally set the rest of the bits from SET. */
bitmap_ior_into (*expanded, set);
return *expanded;
}
/* Union solution sets TO and DELTA, and add INC to each member of DELTA in the
process. */
static bool
set_union_with_increment (bitmap to, bitmap delta, HOST_WIDE_INT inc,
bitmap *expanded_delta)
{
bool changed = false;
bitmap_iterator bi;
unsigned int i;
/* If the solution of DELTA contains anything it is good enough to transfer
this to TO. */
if (bitmap_bit_p (delta, anything_id))
return bitmap_set_bit (to, anything_id);
/* If the offset is unknown we have to expand the solution to
all subfields. */
if (inc == UNKNOWN_OFFSET)
{
delta = solution_set_expand (delta, expanded_delta);
changed |= bitmap_ior_into (to, delta);
return changed;
}
/* For non-zero offset union the offsetted solution into the destination. */
EXECUTE_IF_SET_IN_BITMAP (delta, 0, i, bi)
{
varinfo_t vi = get_varinfo (i);
/* If this is a variable with just one field just set its bit
in the result. */
if (vi->is_artificial_var
|| vi->is_unknown_size_var
|| vi->is_full_var)
changed |= bitmap_set_bit (to, i);
else
{
HOST_WIDE_INT fieldoffset = vi->offset + inc;
unsigned HOST_WIDE_INT size = vi->size;
/* If the offset makes the pointer point to before the
variable use offset zero for the field lookup. */
if (fieldoffset < 0)
vi = get_varinfo (vi->head);
else
vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
do
{
changed |= bitmap_set_bit (to, vi->id);
if (vi->is_full_var
|| vi->next == 0)
break;
/* We have to include all fields that overlap the current field
shifted by inc. */
vi = vi_next (vi);
}
while (vi->offset < fieldoffset + size);
}
}
return changed;
}
/* Insert constraint C into the list of complex constraints for graph
node VAR. */
static void
insert_into_complex (constraint_graph_t graph,
unsigned int var, constraint_t c)
{
vec<constraint_t> complex = graph->complex[var];
unsigned int place = complex.lower_bound (c, constraint_less);
/* Only insert constraints that do not already exist. */
if (place >= complex.length ()
|| !constraint_equal (*c, *complex[place]))
graph->complex[var].safe_insert (place, c);
}
/* Condense two variable nodes into a single variable node, by moving
all associated info from FROM to TO. Returns true if TO node's
constraint set changes after the merge. */
static bool
merge_node_constraints (constraint_graph_t graph, unsigned int to,
unsigned int from)
{
unsigned int i;
constraint_t c;
bool any_change = false;
gcc_checking_assert (find (from) == to);
/* Move all complex constraints from src node into to node */
FOR_EACH_VEC_ELT (graph->complex[from], i, c)
{
/* In complex constraints for node FROM, we may have either
a = *FROM, and *FROM = a, or an offseted constraint which are
always added to the rhs node's constraints. */
if (c->rhs.type == DEREF)
c->rhs.var = to;
else if (c->lhs.type == DEREF)
c->lhs.var = to;
else
c->rhs.var = to;
}
any_change = constraint_set_union (&graph->complex[to],
&graph->complex[from]);
graph->complex[from].release ();
return any_change;
}
/* Remove edges involving NODE from GRAPH. */
static void
clear_edges_for_node (constraint_graph_t graph, unsigned int node)
{
if (graph->succs[node])
BITMAP_FREE (graph->succs[node]);
}
/* Merge GRAPH nodes FROM and TO into node TO. */
static void
merge_graph_nodes (constraint_graph_t graph, unsigned int to,
unsigned int from)
{
if (graph->indirect_cycles[from] != -1)
{
/* If we have indirect cycles with the from node, and we have
none on the to node, the to node has indirect cycles from the
from node now that they are unified.
If indirect cycles exist on both, unify the nodes that they
are in a cycle with, since we know they are in a cycle with
each other. */
if (graph->indirect_cycles[to] == -1)
graph->indirect_cycles[to] = graph->indirect_cycles[from];
}
/* Merge all the successor edges. */
if (graph->succs[from])
{
if (!graph->succs[to])
graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
bitmap_ior_into (graph->succs[to],
graph->succs[from]);
}
clear_edges_for_node (graph, from);
}
/* Add an indirect graph edge to GRAPH, going from TO to FROM if
it doesn't exist in the graph already. */
static void
add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
unsigned int from)
{
if (to == from)
return;
if (!graph->implicit_preds[to])
graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
if (bitmap_set_bit (graph->implicit_preds[to], from))
stats.num_implicit_edges++;
}
/* Add a predecessor graph edge to GRAPH, going from TO to FROM if
it doesn't exist in the graph already.
Return false if the edge already existed, true otherwise. */
static void
add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
unsigned int from)
{
if (!graph->preds[to])
graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
bitmap_set_bit (graph->preds[to], from);
}
/* Add a graph edge to GRAPH, going from FROM to TO if
it doesn't exist in the graph already.
Return false if the edge already existed, true otherwise. */
static bool
add_graph_edge (constraint_graph_t graph, unsigned int to,
unsigned int from)
{
if (to == from)
{
return false;
}
else
{
bool r = false;
if (!graph->succs[from])
graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
/* The graph solving process does not avoid "triangles", thus
there can be multiple paths from a node to another involving
intermediate other nodes. That causes extra copying which is
most difficult to avoid when the intermediate node is ESCAPED
because there are no edges added from ESCAPED. Avoid
adding the direct edge FROM -> TO when we have FROM -> ESCAPED
and TO contains ESCAPED.
??? Note this is only a heuristic, it does not prevent the
situation from occuring. The heuristic helps PR38474 and
PR99912 significantly. */
if (to < FIRST_REF_NODE
&& bitmap_bit_p (graph->succs[from], find (escaped_id))
&& bitmap_bit_p (get_varinfo (find (to))->solution, escaped_id))
return false;
if (bitmap_set_bit (graph->succs[from], to))
{
r = true;
if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
stats.num_edges++;
}
return r;
}
}
/* Initialize the constraint graph structure to contain SIZE nodes. */
static void
init_graph (unsigned int size)
{
unsigned int j;
graph = XCNEW (struct constraint_graph);
graph->size = size;
graph->succs = XCNEWVEC (bitmap, graph->size);
graph->indirect_cycles = XNEWVEC (int, graph->size);
graph->rep = XNEWVEC (unsigned int, graph->size);
/* ??? Macros do not support template types with multiple arguments,
so we use a typedef to work around it. */
typedef vec<constraint_t> vec_constraint_t_heap;
graph->complex = XCNEWVEC (vec_constraint_t_heap, size);
graph->pe = XCNEWVEC (unsigned int, graph->size);
graph->pe_rep = XNEWVEC (int, graph->size);
for (j = 0; j < graph->size; j++)
{
graph->rep[j] = j;
graph->pe_rep[j] = -1;
graph->indirect_cycles[j] = -1;
}
}
/* Build the constraint graph, adding only predecessor edges right now. */
static void
build_pred_graph (void)
{
int i;
constraint_t c;
unsigned int j;
graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
graph->preds = XCNEWVEC (bitmap, graph->size);
graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
graph->loc_label = XCNEWVEC (unsigned int, graph->size);
graph->pointed_by = XCNEWVEC (bitmap, graph->size);
graph->points_to = XCNEWVEC (bitmap, graph->size);
graph->eq_rep = XNEWVEC (int, graph->size);
graph->direct_nodes = sbitmap_alloc (graph->size);
graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
bitmap_clear (graph->direct_nodes);
for (j = 1; j < FIRST_REF_NODE; j++)
{
if (!get_varinfo (j)->is_special_var)
bitmap_set_bit (graph->direct_nodes, j);
}
for (j = 0; j < graph->size; j++)
graph->eq_rep[j] = -1;
for (j = 0; j < varmap.length (); j++)
graph->indirect_cycles[j] = -1;
FOR_EACH_VEC_ELT (constraints, i, c)
{
struct constraint_expr lhs = c->lhs;
struct constraint_expr rhs = c->rhs;
unsigned int lhsvar = lhs.var;
unsigned int rhsvar = rhs.var;
if (lhs.type == DEREF)
{
/* *x = y. */
if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
}
else if (rhs.type == DEREF)
{
/* x = *y */
if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
else
bitmap_clear_bit (graph->direct_nodes, lhsvar);
}
else if (rhs.type == ADDRESSOF)
{
varinfo_t v;
/* x = &y */
if (graph->points_to[lhsvar] == NULL)
graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
if (graph->pointed_by[rhsvar] == NULL)
graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
/* Implicitly, *x = y */
add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
/* All related variables are no longer direct nodes. */
bitmap_clear_bit (graph->direct_nodes, rhsvar);
v = get_varinfo (rhsvar);
if (!v->is_full_var)
{
v = get_varinfo (v->head);
do
{
bitmap_clear_bit (graph->direct_nodes, v->id);
v = vi_next (v);
}
while (v != NULL);
}
bitmap_set_bit (graph->address_taken, rhsvar);
}
else if (lhsvar > anything_id
&& lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
{
/* x = y */
add_pred_graph_edge (graph, lhsvar, rhsvar);
/* Implicitly, *x = *y */
add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
FIRST_REF_NODE + rhsvar);
}
else if (lhs.offset != 0 || rhs.offset != 0)
{
if (rhs.offset != 0)
bitmap_clear_bit (graph->direct_nodes, lhs.var);
else if (lhs.offset != 0)
bitmap_clear_bit (graph->direct_nodes, rhs.var);
}
}
}
/* Build the constraint graph, adding successor edges. */
static void
build_succ_graph (void)
{
unsigned i, t;
constraint_t c;
FOR_EACH_VEC_ELT (constraints, i, c)
{
struct constraint_expr lhs;
struct constraint_expr rhs;
unsigned int lhsvar;
unsigned int rhsvar;
if (!c)
continue;
lhs = c->lhs;
rhs = c->rhs;
lhsvar = find (lhs.var);
rhsvar = find (rhs.var);
if (lhs.type == DEREF)
{
if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
}
else if (rhs.type == DEREF)
{
if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
}
else if (rhs.type == ADDRESSOF)
{
/* x = &y */
gcc_checking_assert (find (rhs.var) == rhs.var);
bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
}
else if (lhsvar > anything_id
&& lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
{
add_graph_edge (graph, lhsvar, rhsvar);
}
}
/* Add edges from STOREDANYTHING to all non-direct nodes that can
receive pointers. */
t = find (storedanything_id);
for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
{
if (!bitmap_bit_p (graph->direct_nodes, i)
&& get_varinfo (i)->may_have_pointers)
add_graph_edge (graph, find (i), t);
}
/* Everything stored to ANYTHING also potentially escapes. */
add_graph_edge (graph, find (escaped_id), t);
}
/* Changed variables on the last iteration. */
static bitmap changed;
/* Strongly Connected Component visitation info. */
class scc_info
{
public:
scc_info (size_t size);
~scc_info ();
auto_sbitmap visited;
auto_sbitmap deleted;
unsigned int *dfs;
unsigned int *node_mapping;
int current_index;
auto_vec<unsigned> scc_stack;
};
/* Recursive routine to find strongly connected components in GRAPH.
SI is the SCC info to store the information in, and N is the id of current
graph node we are processing.
This is Tarjan's strongly connected component finding algorithm, as
modified by Nuutila to keep only non-root nodes on the stack.
The algorithm can be found in "On finding the strongly connected
connected components in a directed graph" by Esko Nuutila and Eljas
Soisalon-Soininen, in Information Processing Letters volume 49,
number 1, pages 9-14. */
static void
scc_visit (constraint_graph_t graph, class scc_info *si, unsigned int n)
{
unsigned int i;
bitmap_iterator bi;
unsigned int my_dfs;
bitmap_set_bit (si->visited, n);
si->dfs[n] = si->current_index ++;
my_dfs = si->dfs[n];
/* Visit all the successors. */
EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
{
unsigned int w;
if (i > LAST_REF_NODE)
break;
w = find (i);
if (bitmap_bit_p (si->deleted, w))
continue;
if (!bitmap_bit_p (si->visited, w))
scc_visit (graph, si, w);
unsigned int t = find (w);
gcc_checking_assert (find (n) == n);
if (si->dfs[t] < si->dfs[n])
si->dfs[n] = si->dfs[t];
}
/* See if any components have been identified. */
if (si->dfs[n] == my_dfs)
{
if (si->scc_stack.length () > 0
&& si->dfs[si->scc_stack.last ()] >= my_dfs)
{
bitmap scc = BITMAP_ALLOC (NULL);
unsigned int lowest_node;
bitmap_iterator bi;
bitmap_set_bit (scc, n);
while (si->scc_stack.length () != 0
&& si->dfs[si->scc_stack.last ()] >= my_dfs)
{
unsigned int w = si->scc_stack.pop ();
bitmap_set_bit (scc, w);
}
lowest_node = bitmap_first_set_bit (scc);
gcc_assert (lowest_node < FIRST_REF_NODE);
/* Collapse the SCC nodes into a single node, and mark the
indirect cycles. */
EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
{
if (i < FIRST_REF_NODE)
{
if (unite (lowest_node, i))
unify_nodes (graph, lowest_node, i, false);
}
else
{
unite (lowest_node, i);
graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
}
}
}
bitmap_set_bit (si->deleted, n);
}
else
si->scc_stack.safe_push (n);
}
/* Unify node FROM into node TO, updating the changed count if
necessary when UPDATE_CHANGED is true. */
static void
unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
bool update_changed)
{
gcc_checking_assert (to != from && find (to) == to);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Unifying %s to %s\n",
get_varinfo (from)->name,
get_varinfo (to)->name);
if (update_changed)
stats.unified_vars_dynamic++;
else
stats.unified_vars_static++;
merge_graph_nodes (graph, to, from);
if (merge_node_constraints (graph, to, from))
{
if (update_changed)
bitmap_set_bit (changed, to);
}
/* Mark TO as changed if FROM was changed. If TO was already marked
as changed, decrease the changed count. */
if (update_changed
&& bitmap_clear_bit (changed, from))
bitmap_set_bit (changed, to);
varinfo_t fromvi = get_varinfo (from);
if (fromvi->solution)
{
/* If the solution changes because of the merging, we need to mark
the variable as changed. */
varinfo_t tovi = get_varinfo (to);
if (bitmap_ior_into (tovi->solution, fromvi->solution))
{
if (update_changed)
bitmap_set_bit (changed, to);
}
BITMAP_FREE (fromvi->solution);
if (fromvi->oldsolution)
BITMAP_FREE (fromvi->oldsolution);
if (stats.iterations > 0
&& tovi->oldsolution)
BITMAP_FREE (tovi->oldsolution);
}
if (graph->succs[to])
bitmap_clear_bit (graph->succs[to], to);
}
/* Information needed to compute the topological ordering of a graph. */
struct topo_info
{
/* sbitmap of visited nodes. */
sbitmap visited;
/* Array that stores the topological order of the graph, *in
reverse*. */
vec<unsigned> topo_order;
};
/* Initialize and return a topological info structure. */
static struct topo_info *
init_topo_info (void)
{
size_t size = graph->size;
struct topo_info *ti = XNEW (struct topo_info);
ti->visited = sbitmap_alloc (size);
bitmap_clear (ti->visited);
ti->topo_order.create (1);
return ti;
}
/* Free the topological sort info pointed to by TI. */
static void
free_topo_info (struct topo_info *ti)
{
sbitmap_free (ti->visited);
ti->topo_order.release ();
free (ti);
}
/* Visit the graph in topological order, and store the order in the
topo_info structure. */
static void
topo_visit (constraint_graph_t graph, struct topo_info *ti,
unsigned int n)
{
bitmap_iterator bi;
unsigned int j;
bitmap_set_bit (ti->visited, n);
if (graph->succs[n])
EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
{
if (!bitmap_bit_p (ti->visited, j))
topo_visit (graph, ti, j);
}
ti->topo_order.safe_push (n);
}
/* Process a constraint C that represents x = *(y + off), using DELTA as the
starting solution for y. */
static void
do_sd_constraint (constraint_graph_t graph, constraint_t c,
bitmap delta, bitmap *expanded_delta)
{
unsigned int lhs = c->lhs.var;
bool flag = false;
bitmap sol = get_varinfo (lhs)->solution;
unsigned int j;
bitmap_iterator bi;
HOST_WIDE_INT roffset = c->rhs.offset;
/* Our IL does not allow this. */
gcc_checking_assert (c->lhs.offset == 0);
/* If the solution of Y contains anything it is good enough to transfer
this to the LHS. */
if (bitmap_bit_p (delta, anything_id))
{
flag |= bitmap_set_bit (sol, anything_id);
goto done;
}
/* If we do not know at with offset the rhs is dereferenced compute
the reachability set of DELTA, conservatively assuming it is
dereferenced at all valid offsets. */
if (roffset == UNKNOWN_OFFSET)
{
delta = solution_set_expand (delta, expanded_delta);
/* No further offset processing is necessary. */
roffset = 0;
}
/* For each variable j in delta (Sol(y)), add
an edge in the graph from j to x, and union Sol(j) into Sol(x). */
EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
{
varinfo_t v = get_varinfo (j);
HOST_WIDE_INT fieldoffset = v->offset + roffset;
unsigned HOST_WIDE_INT size = v->size;
unsigned int t;
if (v->is_full_var)
;
else if (roffset != 0)
{
if (fieldoffset < 0)
v = get_varinfo (v->head);
else
v = first_or_preceding_vi_for_offset (v, fieldoffset);
}
/* We have to include all fields that overlap the current field
shifted by roffset. */
do
{
t = find (v->id);
/* Adding edges from the special vars is pointless.
They don't have sets that can change. */
if (get_varinfo (t)->is_special_var)
flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
/* Merging the solution from ESCAPED needlessly increases
the set. Use ESCAPED as representative instead. */
else if (v->id == escaped_id)
flag |= bitmap_set_bit (sol, escaped_id);
else if (v->may_have_pointers
&& add_graph_edge (graph, lhs, t))
flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
if (v->is_full_var
|| v->next == 0)
break;
v = vi_next (v);
}
while (v->offset < fieldoffset + size);
}
done:
/* If the LHS solution changed, mark the var as changed. */
if (flag)
{
get_varinfo (lhs)->solution = sol;
bitmap_set_bit (changed, lhs);
}
}
/* Process a constraint C that represents *(x + off) = y using DELTA
as the starting solution for x. */
static void
do_ds_constraint (constraint_t c, bitmap delta, bitmap *expanded_delta)
{
unsigned int rhs = c->rhs.var;
bitmap sol = get_varinfo (rhs)->solution;
unsigned int j;
bitmap_iterator bi;
HOST_WIDE_INT loff = c->lhs.offset;
bool escaped_p = false;
/* Our IL does not allow this. */
gcc_checking_assert (c->rhs.offset == 0);
/* If the solution of y contains ANYTHING simply use the ANYTHING
solution. This avoids needlessly increasing the points-to sets. */
if (bitmap_bit_p (sol, anything_id))
sol = get_varinfo (find (anything_id))->solution;
/* If the solution for x contains ANYTHING we have to merge the
solution of y into all pointer variables which we do via
STOREDANYTHING. */
if (bitmap_bit_p (delta, anything_id))
{
unsigned t = find (storedanything_id);
if (add_graph_edge (graph, t, rhs))
{
if (bitmap_ior_into (get_varinfo (t)->solution, sol))
bitmap_set_bit (changed, t);
}
return;
}
/* If we do not know at with offset the rhs is dereferenced compute
the reachability set of DELTA, conservatively assuming it is
dereferenced at all valid offsets. */
if (loff == UNKNOWN_OFFSET)
{
delta = solution_set_expand (delta, expanded_delta);
loff = 0;
}
/* For each member j of delta (Sol(x)), add an edge from y to j and
union Sol(y) into Sol(j) */
EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
{
varinfo_t v = get_varinfo (j);
unsigned int t;
HOST_WIDE_INT fieldoffset = v->offset + loff;
unsigned HOST_WIDE_INT size = v->size;
if (v->is_full_var)
;
else if (loff != 0)
{
if (fieldoffset < 0)
v = get_varinfo (v->head);
else
v = first_or_preceding_vi_for_offset (v, fieldoffset);
}
/* We have to include all fields that overlap the current field
shifted by loff. */
do
{
if (v->may_have_pointers)
{
/* If v is a global variable then this is an escape point. */
if (v->is_global_var
&& !escaped_p)
{
t = find (escaped_id);
if (add_graph_edge (graph, t, rhs)
&& bitmap_ior_into (get_varinfo (t)->solution, sol))
bitmap_set_bit (changed, t);
/* Enough to let rhs escape once. */
escaped_p = true;
}
if (v->is_special_var)
break;
t = find (v->id);
if (add_graph_edge (graph, t, rhs)
&& bitmap_ior_into (get_varinfo (t)->solution, sol))
bitmap_set_bit (changed, t);
}
if (v->is_full_var
|| v->next == 0)
break;
v = vi_next (v);
}
while (v->offset < fieldoffset + size);
}
}
/* Handle a non-simple (simple meaning requires no iteration),
constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
static void
do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta,
bitmap *expanded_delta)
{
if (c->lhs.type == DEREF)
{
if (c->rhs.type == ADDRESSOF)
{
gcc_unreachable ();
}
else
{
/* *x = y */
do_ds_constraint (c, delta, expanded_delta);
}
}
else if (c->rhs.type == DEREF)
{
/* x = *y */
if (!(get_varinfo (c->lhs.var)->is_special_var))
do_sd_constraint (graph, c, delta, expanded_delta);
}
else
{
bitmap tmp;
bool flag = false;
gcc_checking_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR
&& c->rhs.offset != 0 && c->lhs.offset == 0);
tmp = get_varinfo (c->lhs.var)->solution;
flag = set_union_with_increment (tmp, delta, c->rhs.offset,
expanded_delta);
if (flag)
bitmap_set_bit (changed, c->lhs.var);
}
}
/* Initialize and return a new SCC info structure. */
scc_info::scc_info (size_t size) :
visited (size), deleted (size), current_index (0), scc_stack (1)
{
bitmap_clear (visited);
bitmap_clear (deleted);
node_mapping = XNEWVEC (unsigned int, size);
dfs = XCNEWVEC (unsigned int, size);
for (size_t i = 0; i < size; i++)
node_mapping[i] = i;
}
/* Free an SCC info structure pointed to by SI */
scc_info::~scc_info ()
{
free (node_mapping);
free (dfs);
}
/* Find indirect cycles in GRAPH that occur, using strongly connected
components, and note them in the indirect cycles map.
This technique comes from Ben Hardekopf and Calvin Lin,
"It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
Lines of Code", submitted to PLDI 2007. */
static void
find_indirect_cycles (constraint_graph_t graph)
{
unsigned int i;
unsigned int size = graph->size;
scc_info si (size);
for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
if (!bitmap_bit_p (si.visited, i) && find (i) == i)
scc_visit (graph, &si, i);
}
/* Compute a topological ordering for GRAPH, and store the result in the
topo_info structure TI. */
static void
compute_topo_order (constraint_graph_t graph,
struct topo_info *ti)
{
unsigned int i;
unsigned int size = graph->size;
for (i = 0; i != size; ++i)
if (!bitmap_bit_p (ti->visited, i) && find (i) == i)
topo_visit (graph, ti, i);
}
/* Structure used to for hash value numbering of pointer equivalence
classes. */
typedef struct equiv_class_label
{
hashval_t hashcode;
unsigned int equivalence_class;
bitmap labels;
} *equiv_class_label_t;
typedef const struct equiv_class_label *const_equiv_class_label_t;
/* Equiv_class_label hashtable helpers. */
struct equiv_class_hasher : nofree_ptr_hash <equiv_class_label>
{
static inline hashval_t hash (const equiv_class_label *);
static inline bool equal (const equiv_class_label *,
const equiv_class_label *);
};
/* Hash function for a equiv_class_label_t */
inline hashval_t
equiv_class_hasher::hash (const equiv_class_label *ecl)
{
return ecl->hashcode;
}
/* Equality function for two equiv_class_label_t's. */
inline bool
equiv_class_hasher::equal (const equiv_class_label *eql1,
const equiv_class_label *eql2)
{
return (eql1->hashcode == eql2->hashcode
&& bitmap_equal_p (eql1->labels, eql2->labels));
}
/* A hashtable for mapping a bitmap of labels->pointer equivalence
classes. */
static hash_table<equiv_class_hasher> *pointer_equiv_class_table;
/* A hashtable for mapping a bitmap of labels->location equivalence
classes. */
static hash_table<equiv_class_hasher> *location_equiv_class_table;
struct obstack equiv_class_obstack;
/* Lookup a equivalence class in TABLE by the bitmap of LABELS with
hash HAS it contains. Sets *REF_LABELS to the bitmap LABELS
is equivalent to. */
static equiv_class_label *
equiv_class_lookup_or_add (hash_table<equiv_class_hasher> *table,
bitmap labels)
{
equiv_class_label **slot;
equiv_class_label ecl;
ecl.labels = labels;
ecl.hashcode = bitmap_hash (labels);
slot = table->find_slot (&ecl, INSERT);
if (!*slot)
{
*slot = XOBNEW (&equiv_class_obstack, struct equiv_class_label);
(*slot)->labels = labels;
(*slot)->hashcode = ecl.hashcode;
(*slot)->equivalence_class = 0;
}
return *slot;
}
/* Perform offline variable substitution.
This is a worst case quadratic time way of identifying variables
that must have equivalent points-to sets, including those caused by
static cycles, and single entry subgraphs, in the constraint graph.
The technique is described in "Exploiting Pointer and Location
Equivalence to Optimize Pointer Analysis. In the 14th International
Static Analysis Symposium (SAS), August 2007." It is known as the
"HU" algorithm, and is equivalent to value numbering the collapsed
constraint graph including evaluating unions.
The general method of finding equivalence classes is as follows:
Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
Initialize all non-REF nodes to be direct nodes.
For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
variable}
For each constraint containing the dereference, we also do the same
thing.
We then compute SCC's in the graph and unify nodes in the same SCC,
including pts sets.
For each non-collapsed node x:
Visit all unvisited explicit incoming edges.
Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
where y->x.
Lookup the equivalence class for pts(x).
If we found one, equivalence_class(x) = found class.
Otherwise, equivalence_class(x) = new class, and new_class is
added to the lookup table.
All direct nodes with the same equivalence class can be replaced
with a single representative node.
All unlabeled nodes (label == 0) are not pointers and all edges
involving them can be eliminated.
We perform these optimizations during rewrite_constraints
In addition to pointer equivalence class finding, we also perform
location equivalence class finding. This is the set of variables
that always appear together in points-to sets. We use this to
compress the size of the points-to sets. */
/* Current maximum pointer equivalence class id. */
static int pointer_equiv_class;
/* Current maximum location equivalence class id. */
static int location_equiv_class;
/* Recursive routine to find strongly connected components in GRAPH,
and label it's nodes with DFS numbers. */
static void
condense_visit (constraint_graph_t graph, class scc_info *si, unsigned int n)
{
unsigned int i;
bitmap_iterator bi;
unsigned int my_dfs;
gcc_checking_assert (si->node_mapping[n] == n);
bitmap_set_bit (si->visited, n);
si->dfs[n] = si->current_index ++;
my_dfs = si->dfs[n];
/* Visit all the successors. */
EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
{
unsigned int w = si->node_mapping[i];
if (bitmap_bit_p (si->deleted, w))
continue;
if (!bitmap_bit_p (si->visited, w))
condense_visit (graph, si, w);
unsigned int t = si->node_mapping[w];
gcc_checking_assert (si->node_mapping[n] == n);
if (si->dfs[t] < si->dfs[n])
si->dfs[n] = si->dfs[t];
}
/* Visit all the implicit predecessors. */
EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
{
unsigned int w = si->node_mapping[i];
if (bitmap_bit_p (si->deleted, w))
continue;
if (!bitmap_bit_p (si->visited, w))
condense_visit (graph, si, w);
unsigned int t = si->node_mapping[w];
gcc_assert (si->node_mapping[n] == n);
if (si->dfs[t] < si->dfs[n])
si->dfs[n] = si->dfs[t];
}
/* See if any components have been identified. */
if (si->dfs[n] == my_dfs)
{
if (si->scc_stack.length () != 0
&& si->dfs[si->scc_stack.last ()] >= my_dfs)
{
/* Find the first node of the SCC and do non-bitmap work. */
bool direct_p = true;
unsigned first = si->scc_stack.length ();
do
{
--first;
unsigned int w = si->scc_stack[first];
si->node_mapping[w] = n;
if (!bitmap_bit_p (graph->direct_nodes, w))
direct_p = false;
}
while (first > 0
&& si->dfs[si->scc_stack[first - 1]] >= my_dfs);
if (!direct_p)
bitmap_clear_bit (graph->direct_nodes, n);
/* Want to reduce to node n, push that first. */
si->scc_stack.reserve (1);
si->scc_stack.quick_push (si->scc_stack[first]);
si->scc_stack[first] = n;
unsigned scc_size = si->scc_stack.length () - first;
unsigned split = scc_size / 2;
unsigned carry = scc_size - split * 2;
while (split > 0)
{
for (unsigned i = 0; i < split; ++i)
{
unsigned a = si->scc_stack[first + i];
unsigned b = si->scc_stack[first + split + carry + i];
/* Unify our nodes. */
if (graph->preds[b])
{
if (!graph->preds[a])
std::swap (graph->preds[a], graph->preds[b]);
else
bitmap_ior_into_and_free (graph->preds[a],
&graph->preds[b]);
}
if (graph->implicit_preds[b])
{
if (!graph->implicit_preds[a])
std::swap (graph->implicit_preds[a],
graph->implicit_preds[b]);
else
bitmap_ior_into_and_free (graph->implicit_preds[a],
&graph->implicit_preds[b]);
}
if (graph->points_to[b])
{
if (!graph->points_to[a])
std::swap (graph->points_to[a], graph->points_to[b]);
else
bitmap_ior_into_and_free (graph->points_to[a],
&graph->points_to[b]);
}
}
unsigned remain = split + carry;
split = remain / 2;
carry = remain - split * 2;
}
/* Actually pop the SCC. */
si->scc_stack.truncate (first);
}
bitmap_set_bit (si->deleted, n);
}
else
si->scc_stack.safe_push (n);
}
/* Label pointer equivalences.
This performs a value numbering of the constraint graph to
discover which variables will always have the same points-to sets
under the current set of constraints.
The way it value numbers is to store the set of points-to bits
generated by the constraints and graph edges. This is just used as a
hash and equality comparison. The *actual set of points-to bits* is
completely irrelevant, in that we don't care about being able to
extract them later.
The equality values (currently bitmaps) just have to satisfy a few
constraints, the main ones being:
1. The combining operation must be order independent.
2. The end result of a given set of operations must be unique iff the
combination of input values is unique
3. Hashable. */
static void
label_visit (constraint_graph_t graph, class scc_info *si, unsigned int n)
{
unsigned int i, first_pred;
bitmap_iterator bi;
bitmap_set_bit (si->visited, n);
/* Label and union our incoming edges's points to sets. */
first_pred = -1U;
EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
{
unsigned int w = si->node_mapping[i];
if (!bitmap_bit_p (si->visited, w))
label_visit (graph, si, w);
/* Skip unused edges */
if (w == n || graph->pointer_label[w] == 0)
continue;
if (graph->points_to[w])
{
if (!graph->points_to[n])
{
if (first_pred == -1U)
first_pred = w;
else
{
graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
bitmap_ior (graph->points_to[n],
graph->points_to[first_pred],
graph->points_to[w]);
}
}
else
bitmap_ior_into (graph->points_to[n], graph->points_to[w]);
}
}
/* Indirect nodes get fresh variables and a new pointer equiv class. */
if (!bitmap_bit_p (graph->direct_nodes, n))
{
if (!graph->points_to[n])
{
graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
if (first_pred != -1U)
bitmap_copy (graph->points_to[n], graph->points_to[first_pred]);
}
bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
graph->pointer_label[n] = pointer_equiv_class++;
equiv_class_label_t ecl;
ecl = equiv_class_lookup_or_add (pointer_equiv_class_table,
graph->points_to[n]);
ecl->equivalence_class = graph->pointer_label[n];
return;
}
/* If there was only a single non-empty predecessor the pointer equiv
class is the same. */
if (!graph->points_to[n])
{
if (first_pred != -1U)
{
graph->pointer_label[n] = graph->pointer_label[first_pred];
graph->points_to[n] = graph->points_to[first_pred];
}
return;
}
if (!bitmap_empty_p (graph->points_to[n]))
{
equiv_class_label_t ecl;
ecl = equiv_class_lookup_or_add (pointer_equiv_class_table,
graph->points_to[n]);
if (ecl->equivalence_class == 0)
ecl->equivalence_class = pointer_equiv_class++;
else
{
BITMAP_FREE (graph->points_to[n]);
graph->points_to[n] = ecl->labels;
}
graph->pointer_label[n] = ecl->equivalence_class;
}
}
/* Print the pred graph in dot format. */
static void
dump_pred_graph (class scc_info *si, FILE *file)
{
unsigned int i;
/* Only print the graph if it has already been initialized: */
if (!graph)
return;
/* Prints the header of the dot file: */
fprintf (file, "strict digraph {\n");
fprintf (file, " node [\n shape = box\n ]\n");
fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
fprintf (file, "\n // List of nodes and complex constraints in "
"the constraint graph:\n");
/* The next lines print the nodes in the graph together with the
complex constraints attached to them. */
for (i = 1; i < graph->size; i++)
{
if (i == FIRST_REF_NODE)
continue;
if (si->node_mapping[i] != i)
continue;
if (i < FIRST_REF_NODE)
fprintf (file, "\"%s\"", get_varinfo (i)->name);
else
fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
if (graph->points_to[i]
&& !bitmap_empty_p (graph->points_to[i]))
{
if (i < FIRST_REF_NODE)
fprintf (file, "[label=\"%s = {", get_varinfo (i)->name);
else
fprintf (file, "[label=\"*%s = {",
get_varinfo (i - FIRST_REF_NODE)->name);
unsigned j;
bitmap_iterator bi;
EXECUTE_IF_SET_IN_BITMAP (graph->points_to[i], 0, j, bi)
fprintf (file, " %d", j);
fprintf (file, " }\"]");
}
fprintf (file, ";\n");
}
/* Go over the edges. */
fprintf (file, "\n // Edges in the constraint graph:\n");
for (i = 1; i < graph->size; i++)
{
unsigned j;
bitmap_iterator bi;
if (si->node_mapping[i] != i)
continue;
EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[i], 0, j, bi)
{
unsigned from = si->node_mapping[j];
if (from < FIRST_REF_NODE)
fprintf (file, "\"%s\"", get_varinfo (from)->name);
else
fprintf (file, "\"*%s\"", get_varinfo (from - FIRST_REF_NODE)->name);
fprintf (file, " -> ");
if (i < FIRST_REF_NODE)
fprintf (file, "\"%s\"", get_varinfo (i)->name);
else
fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
fprintf (file, ";\n");
}
}
/* Prints the tail of the dot file. */
fprintf (file, "}\n");
}
/* Perform offline variable substitution, discovering equivalence
classes, and eliminating non-pointer variables. */
static class scc_info *
perform_var_substitution (constraint_graph_t graph)
{
unsigned int i;
unsigned int size = graph->size;
scc_info *si = new scc_info (size);
bitmap_obstack_initialize (&iteration_obstack);
gcc_obstack_init (&equiv_class_obstack);
pointer_equiv_class_table = new hash_table<equiv_class_hasher> (511);
location_equiv_class_table
= new hash_table<equiv_class_hasher> (511);
pointer_equiv_class = 1;
location_equiv_class = 1;
/* Condense the nodes, which means to find SCC's, count incoming
predecessors, and unite nodes in SCC's. */
for (i = 1; i < FIRST_REF_NODE; i++)
if (!bitmap_bit_p (si->visited, si->node_mapping[i]))
condense_visit (graph, si, si->node_mapping[i]);
if (dump_file && (dump_flags & TDF_GRAPH))
{
fprintf (dump_file, "\n\n// The constraint graph before var-substitution "
"in dot format:\n");
dump_pred_graph (si, dump_file);
fprintf (dump_file, "\n\n");
}
bitmap_clear (si->visited);
/* Actually the label the nodes for pointer equivalences */
for (i = 1; i < FIRST_REF_NODE; i++)
if (!bitmap_bit_p (si->visited, si->node_mapping[i]))
label_visit (graph, si, si->node_mapping[i]);
/* Calculate location equivalence labels. */
for (i = 1; i < FIRST_REF_NODE; i++)
{
bitmap pointed_by;
bitmap_iterator bi;
unsigned int j;
if (!graph->pointed_by[i])
continue;
pointed_by = BITMAP_ALLOC (&iteration_obstack);
/* Translate the pointed-by mapping for pointer equivalence
labels. */
EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
{
bitmap_set_bit (pointed_by,
graph->pointer_label[si->node_mapping[j]]);
}
/* The original pointed_by is now dead. */
BITMAP_FREE (graph->pointed_by[i]);
/* Look up the location equivalence label if one exists, or make
one otherwise. */
equiv_class_label_t ecl;
ecl = equiv_class_lookup_or_add (location_equiv_class_table, pointed_by);
if (ecl->equivalence_class == 0)
ecl->equivalence_class = location_equiv_class++;
else
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found location equivalence for node %s\n",
get_varinfo (i)->name);
BITMAP_FREE (pointed_by);
}
graph->loc_label[i] = ecl->equivalence_class;
}
if (dump_file && (dump_flags & TDF_DETAILS))
for (i = 1; i < FIRST_REF_NODE; i++)
{
unsigned j = si->node_mapping[i];
if (j != i)
{
fprintf (dump_file, "%s node id %d ",
bitmap_bit_p (graph->direct_nodes, i)
? "Direct" : "Indirect", i);
if (i < FIRST_REF_NODE)
fprintf (dump_file, "\"%s\"", get_varinfo (i)->name);
else
fprintf (dump_file, "\"*%s\"",
get_varinfo (i - FIRST_REF_NODE)->name);
fprintf (dump_file, " mapped to SCC leader node id %d ", j);
if (j < FIRST_REF_NODE)
fprintf (dump_file, "\"%s\"\n", get_varinfo (j)->name);
else
fprintf (dump_file, "\"*%s\"\n",
get_varinfo (j - FIRST_REF_NODE)->name);
}
else
{
fprintf (dump_file,
"Equivalence classes for %s node id %d ",
bitmap_bit_p (graph->direct_nodes, i)
? "direct" : "indirect", i);
if (i < FIRST_REF_NODE)
fprintf (dump_file, "\"%s\"", get_varinfo (i)->name);
else
fprintf (dump_file, "\"*%s\"",
get_varinfo (i - FIRST_REF_NODE)->name);
fprintf (dump_file,
": pointer %d, location %d\n",
graph->pointer_label[i], graph->loc_label[i]);
}
}
/* Quickly eliminate our non-pointer variables. */
for (i = 1; i < FIRST_REF_NODE; i++)
{
unsigned int node = si->node_mapping[i];
if (graph->pointer_label[node] == 0)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"%s is a non-pointer variable, eliminating edges.\n",
get_varinfo (node)->name);
stats.nonpointer_vars++;
clear_edges_for_node (graph, node);
}
}
return si;
}
/* Free information that was only necessary for variable
substitution. */
static void
free_var_substitution_info (class scc_info *si)
{
delete si;
free (graph->pointer_label);
free (graph->loc_label);
free (graph->pointed_by);
free (graph->points_to);
free (graph->eq_rep);
sbitmap_free (graph->direct_nodes);
delete pointer_equiv_class_table;
pointer_equiv_class_table = NULL;
delete location_equiv_class_table;
location_equiv_class_table = NULL;
obstack_free (&equiv_class_obstack, NULL);
bitmap_obstack_release (&iteration_obstack);
}
/* Return an existing node that is equivalent to NODE, which has
equivalence class LABEL, if one exists. Return NODE otherwise. */
static unsigned int
find_equivalent_node (constraint_graph_t graph,
unsigned int node, unsigned int label)
{
/* If the address version of this variable is unused, we can
substitute it for anything else with the same label.
Otherwise, we know the pointers are equivalent, but not the
locations, and we can unite them later. */
if (!bitmap_bit_p (graph->address_taken, node))
{
gcc_checking_assert (label < graph->size);
if (graph->eq_rep[label] != -1)
{
/* Unify the two variables since we know they are equivalent. */
if (unite (graph->eq_rep[label], node))
unify_nodes (graph, graph->eq_rep[label], node, false);
return graph->eq_rep[label];
}
else
{
graph->eq_rep[label] = node;
graph->pe_rep[label] = node;
}
}
else
{
gcc_checking_assert (label < graph->size);
graph->pe[node] = label;
if (graph->pe_rep[label] == -1)
graph->pe_rep[label] = node;
}
return node;
}
/* Unite pointer equivalent but not location equivalent nodes in
GRAPH. This may only be performed once variable substitution is
finished. */
static void
unite_pointer_equivalences (constraint_graph_t graph)
{
unsigned int i;
/* Go through the pointer equivalences and unite them to their
representative, if they aren't already. */
for (i = 1; i < FIRST_REF_NODE; i++)
{
unsigned int label = graph->pe[i];
if (label)
{
int label_rep = graph->pe_rep[label];
if (label_rep == -1)
continue;
label_rep = find (label_rep);
if (label_rep >= 0 && unite (label_rep, find (i)))
unify_nodes (graph, label_rep, i, false);
}
}
}
/* Move complex constraints to the GRAPH nodes they belong to. */
static void
move_complex_constraints (constraint_graph_t graph)
{
int i;
constraint_t c;
FOR_EACH_VEC_ELT (constraints, i, c)
{
if (c)
{
struct constraint_expr lhs = c->lhs;
struct constraint_expr rhs = c->rhs;
if (lhs.type == DEREF)
{
insert_into_complex (graph, lhs.var, c);
}
else if (rhs.type == DEREF)
{
if (!(get_varinfo (lhs.var)->is_special_var))
insert_into_complex (graph, rhs.var, c);
}
else if (rhs.type != ADDRESSOF && lhs.var > anything_id
&& (lhs.offset != 0 || rhs.offset != 0))
{
insert_into_complex (graph, rhs.var, c);
}
}
}
}
/* Optimize and rewrite complex constraints while performing
collapsing of equivalent nodes. SI is the SCC_INFO that is the
result of perform_variable_substitution. */
static void
rewrite_constraints (constraint_graph_t graph,
class scc_info *si)
{
int i;
constraint_t c;
if (flag_checking)
{
for (unsigned int j = 0; j < graph->size; j++)
gcc_assert (find (j) == j);
}
FOR_EACH_VEC_ELT (constraints, i, c)
{
struct constraint_expr lhs = c->lhs;
struct constraint_expr rhs = c->rhs;
unsigned int lhsvar = find (lhs.var);
unsigned int rhsvar = find (rhs.var);
unsigned int lhsnode, rhsnode;
unsigned int lhslabel, rhslabel;
lhsnode = si->node_mapping[lhsvar];
rhsnode = si->node_mapping[rhsvar];
lhslabel = graph->pointer_label[lhsnode];
rhslabel = graph->pointer_label[rhsnode];
/* See if it is really a non-pointer variable, and if so, ignore
the constraint. */
if (lhslabel == 0)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "%s is a non-pointer variable, "
"ignoring constraint:",
get_varinfo (lhs.var)->name);
dump_constraint (dump_file, c);
fprintf (dump_file, "\n");
}
constraints[i] = NULL;
continue;
}
if (rhslabel == 0)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "%s is a non-pointer variable, "
"ignoring constraint:",
get_varinfo (rhs.var)->name);
dump_constraint (dump_file, c);
fprintf (dump_file, "\n");
}
constraints[i] = NULL;
continue;
}
lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
c->lhs.var = lhsvar;
c->rhs.var = rhsvar;
}
}
/* Eliminate indirect cycles involving NODE. Return true if NODE was
part of an SCC, false otherwise. */
static bool
eliminate_indirect_cycles (unsigned int node)
{
if (graph->indirect_cycles[node] != -1
&& !bitmap_empty_p (get_varinfo (node)->solution))
{
unsigned int i;
auto_vec<unsigned> queue;
int queuepos;
unsigned int to = find (graph->indirect_cycles[node]);
bitmap_iterator bi;
/* We can't touch the solution set and call unify_nodes
at the same time, because unify_nodes is going to do
bitmap unions into it. */
EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
{
if (find (i) == i && i != to)
{
if (unite (to, i))
queue.safe_push (i);
}
}
for (queuepos = 0;
queue.iterate (queuepos, &i);
queuepos++)
{
unify_nodes (graph, to, i, true);
}
return true;
}
return false;
}
/* Solve the constraint graph GRAPH using our worklist solver.
This is based on the PW* family of solvers from the "Efficient Field
Sensitive Pointer Analysis for C" paper.
It works by iterating over all the graph nodes, processing the complex
constraints and propagating the copy constraints, until everything stops
changed. This corresponds to steps 6-8 in the solving list given above. */
static void
solve_graph (constraint_graph_t graph)
{
unsigned int size = graph->size;
unsigned int i;
bitmap pts;
changed = BITMAP_ALLOC (NULL);
/* Mark all initial non-collapsed nodes as changed. */
for (i = 1; i < size; i++)
{
varinfo_t ivi = get_varinfo (i);
if (find (i) == i && !bitmap_empty_p (ivi->solution)
&& ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
|| graph->complex[i].length () > 0))
bitmap_set_bit (changed, i);
}
/* Allocate a bitmap to be used to store the changed bits. */
pts = BITMAP_ALLOC (&pta_obstack);
while (!bitmap_empty_p (changed))
{
unsigned int i;
struct topo_info *ti = init_topo_info ();
stats.iterations++;
bitmap_obstack_initialize (&iteration_obstack);
compute_topo_order (graph, ti);
while (ti->topo_order.length () != 0)
{
i = ti->topo_order.pop ();
/* If this variable is not a representative, skip it. */
if (find (i) != i)
continue;
/* In certain indirect cycle cases, we may merge this
variable to another. */
if (eliminate_indirect_cycles (i) && find (i) != i)
continue;
/* If the node has changed, we need to process the
complex constraints and outgoing edges again. */
if (bitmap_clear_bit (changed, i))
{
unsigned int j;
constraint_t c;
bitmap solution;
vec<constraint_t> complex = graph->complex[i];
varinfo_t vi = get_varinfo (i);
bool solution_empty;
/* Compute the changed set of solution bits. If anything
is in the solution just propagate that. */
if (bitmap_bit_p (vi->solution, anything_id))
{
/* If anything is also in the old solution there is
nothing to do.
??? But we shouldn't ended up with "changed" set ... */
if (vi->oldsolution
&& bitmap_bit_p (vi->oldsolution, anything_id))
continue;
bitmap_copy (pts, get_varinfo (find (anything_id))->solution);
}
else if (vi->oldsolution)
bitmap_and_compl (pts, vi->solution, vi->oldsolution);
else
bitmap_copy (pts, vi->solution);
if (bitmap_empty_p (pts))
continue;
if (vi->oldsolution)
bitmap_ior_into (vi->oldsolution, pts);
else
{
vi->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
bitmap_copy (vi->oldsolution, pts);
}
solution = vi->solution;
solution_empty = bitmap_empty_p (solution);
/* Process the complex constraints */
bitmap expanded_pts = NULL;
FOR_EACH_VEC_ELT (complex, j, c)
{
/* XXX: This is going to unsort the constraints in
some cases, which will occasionally add duplicate
constraints during unification. This does not
affect correctness. */
c->lhs.var = find (c->lhs.var);
c->rhs.var = find (c->rhs.var);
/* The only complex constraint that can change our
solution to non-empty, given an empty solution,
is a constraint where the lhs side is receiving
some set from elsewhere. */
if (!solution_empty || c->lhs.type != DEREF)
do_complex_constraint (graph, c, pts, &expanded_pts);
}
BITMAP_FREE (expanded_pts);
solution_empty = bitmap_empty_p (solution);
if (!solution_empty)
{
bitmap_iterator bi;
unsigned eff_escaped_id = find (escaped_id);
/* Propagate solution to all successors. */
unsigned to_remove = ~0U;
EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
0, j, bi)
{
if (to_remove != ~0U)
{
bitmap_clear_bit (graph->succs[i], to_remove);
to_remove = ~0U;
}
unsigned int to = find (j);
if (to != j)
{
/* Update the succ graph, avoiding duplicate
work. */
to_remove = j;
if (! bitmap_set_bit (graph->succs[i], to))
continue;
/* We eventually end up processing 'to' twice
as it is undefined whether bitmap iteration
iterates over bits set during iteration.
Play safe instead of doing tricks. */
}
/* Don't try to propagate to ourselves. */
if (to == i)
continue;
bitmap tmp = get_varinfo (to)->solution;
bool flag = false;
/* If we propagate from ESCAPED use ESCAPED as
placeholder. */
if (i == eff_escaped_id)
flag = bitmap_set_bit (tmp, escaped_id);
else
flag = bitmap_ior_into (tmp, pts);
if (flag)
bitmap_set_bit (changed, to);
}
if (to_remove != ~0U)
bitmap_clear_bit (graph->succs[i], to_remove);
}
}
}
free_topo_info (ti);
bitmap_obstack_release (&iteration_obstack);
}
BITMAP_FREE (pts);
BITMAP_FREE (changed);
bitmap_obstack_release (&oldpta_obstack);
}
/* Map from trees to variable infos. */
static hash_map<tree, varinfo_t> *vi_for_tree;
/* Insert ID as the variable id for tree T in the vi_for_tree map. */
static void
insert_vi_for_tree (tree t, varinfo_t vi)
{
gcc_assert (vi);
gcc_assert (!vi_for_tree->put (t, vi));
}
/* Find the variable info for tree T in VI_FOR_TREE. If T does not
exist in the map, return NULL, otherwise, return the varinfo we found. */
static varinfo_t
lookup_vi_for_tree (tree t)
{
varinfo_t *slot = vi_for_tree->get (t);
if (slot == NULL)
return NULL;
return *slot;
}
/* Return a printable name for DECL */
static const char *
alias_get_name (tree decl)
{
const char *res = "NULL";
if (dump_file)
{
char *temp = NULL;
if (TREE_CODE (decl) == SSA_NAME)
{
res = get_name (decl);
temp = xasprintf ("%s_%u", res ? res : "", SSA_NAME_VERSION (decl));
}
else if (HAS_DECL_ASSEMBLER_NAME_P (decl)
&& DECL_ASSEMBLER_NAME_SET_P (decl))
res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME_RAW (decl));
else if (DECL_P (decl))
{
res = get_name (decl);
if (!res)
temp = xasprintf ("D.%u", DECL_UID (decl));
}
if (temp)
{
res = ggc_strdup (temp);
free (temp);
}
}
return res;
}
/* Find the variable id for tree T in the map.
If T doesn't exist in the map, create an entry for it and return it. */
static varinfo_t
get_vi_for_tree (tree t)
{
varinfo_t *slot = vi_for_tree->get (t);
if (slot == NULL)
{
unsigned int id = create_variable_info_for (t, alias_get_name (t), false);
return get_varinfo (id);
}
return *slot;
}
/* Get a scalar constraint expression for a new temporary variable. */
static struct constraint_expr
new_scalar_tmp_constraint_exp (const char *name, bool add_id)
{
struct constraint_expr tmp;
varinfo_t vi;
vi = new_var_info (NULL_TREE, name, add_id);
vi->offset = 0;
vi->size = -1;
vi->fullsize = -1;
vi->is_full_var = 1;
vi->is_reg_var = 1;
tmp.var = vi->id;
tmp.type = SCALAR;
tmp.offset = 0;
return tmp;
}
/* Get a constraint expression vector from an SSA_VAR_P node.
If address_p is true, the result will be taken its address of. */
static void
get_constraint_for_ssa_var (tree t, vec<ce_s> *results, bool address_p)
{
struct constraint_expr cexpr;
varinfo_t vi;
/* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
gcc_assert (TREE_CODE (t) == SSA_NAME || DECL_P (t));
if (TREE_CODE (t) == SSA_NAME
&& SSA_NAME_IS_DEFAULT_DEF (t))
{
/* For parameters, get at the points-to set for the actual parm
decl. */
if (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
|| TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
{
get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
return;
}
/* For undefined SSA names return nothing. */
else if (!ssa_defined_default_def_p (t))
{
cexpr.var = nothing_id;
cexpr.type = SCALAR;
cexpr.offset = 0;
results->safe_push (cexpr);
return;
}
}
/* For global variables resort to the alias target. */
if (VAR_P (t) && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
{
varpool_node *node = varpool_node::get (t);
if (node && node->alias && node->analyzed)
{
node = node->ultimate_alias_target ();
/* Canonicalize the PT uid of all aliases to the ultimate target.
??? Hopefully the set of aliases can't change in a way that
changes the ultimate alias target. */
gcc_assert ((! DECL_PT_UID_SET_P (node->decl)
|| DECL_PT_UID (node->decl) == DECL_UID (node->decl))
&& (! DECL_PT_UID_SET_P (t)
|| DECL_PT_UID (t) == DECL_UID (node->decl)));
DECL_PT_UID (t) = DECL_UID (node->decl);
t = node->decl;
}
/* If this is decl may bind to NULL note that. */
if (address_p
&& (! node || ! node->nonzero_address ()))
{
cexpr.var = nothing_id;
cexpr.type = SCALAR;
cexpr.offset = 0;
results->safe_push (cexpr);
}
}
vi = get_vi_for_tree (t);
cexpr.var = vi->id;
cexpr.type = SCALAR;
cexpr.offset = 0;
/* If we are not taking the address of the constraint expr, add all
sub-fiels of the variable as well. */
if (!address_p
&& !vi->is_full_var)
{
for (; vi; vi = vi_next (vi))
{
cexpr.var = vi->id;
results->safe_push (cexpr);
}
return;
}
results->safe_push (cexpr);
}
/* Process constraint T, performing various simplifications and then
adding it to our list of overall constraints. */
static void
process_constraint (constraint_t t)
{
struct constraint_expr rhs = t->rhs;
struct constraint_expr lhs = t->lhs;
gcc_assert (rhs.var < varmap.length ());
gcc_assert (lhs.var < varmap.length ());
/* If we didn't get any useful constraint from the lhs we get
&ANYTHING as fallback from get_constraint_for. Deal with
it here by turning it into *ANYTHING. */
if (lhs.type == ADDRESSOF
&& lhs.var == anything_id)
lhs.type = DEREF;
/* ADDRESSOF on the lhs is invalid. */
gcc_assert (lhs.type != ADDRESSOF);
/* We shouldn't add constraints from things that cannot have pointers.
It's not completely trivial to avoid in the callers, so do it here. */
if (rhs.type != ADDRESSOF
&& !get_varinfo (rhs.var)->may_have_pointers)
return;
/* Likewise adding to the solution of a non-pointer var isn't useful. */
if (!get_varinfo (lhs.var)->may_have_pointers)
return;
/* This can happen in our IR with things like n->a = *p */
if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
{
/* Split into tmp = *rhs, *lhs = tmp */
struct constraint_expr tmplhs;
tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp", true);
process_constraint (new_constraint (tmplhs, rhs));
process_constraint (new_constraint (lhs, tmplhs));
}
else if ((rhs.type != SCALAR || rhs.offset != 0) && lhs.type == DEREF)
{
/* Split into tmp = &rhs, *lhs = tmp */
struct constraint_expr tmplhs;
tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp", true);
process_constraint (new_constraint (tmplhs, rhs));
process_constraint (new_constraint (lhs, tmplhs));
}
else
{
gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
if (rhs.type == ADDRESSOF)
get_varinfo (get_varinfo (rhs.var)->head)->address_taken = true;
constraints.safe_push (t);
}
}
/* Return the position, in bits, of FIELD_DECL from the beginning of its
structure. */
static HOST_WIDE_INT
bitpos_of_field (const tree fdecl)
{
if (!tree_fits_shwi_p (DECL_FIELD_OFFSET (fdecl))
|| !tree_fits_shwi_p (DECL_FIELD_BIT_OFFSET (fdecl)))
return -1;
return (tree_to_shwi (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT
+ tree_to_shwi (DECL_FIELD_BIT_OFFSET (fdecl)));
}
/* Get constraint expressions for offsetting PTR by OFFSET. Stores the
resulting constraint expressions in *RESULTS. */
static void
get_constraint_for_ptr_offset (tree ptr, tree offset,
vec<ce_s> *results)
{
struct constraint_expr c;
unsigned int j, n;
HOST_WIDE_INT rhsoffset;
/* If we do not do field-sensitive PTA adding offsets to pointers
does not change the points-to solution. */
if (!use_field_sensitive)
{
get_constraint_for_rhs (ptr, results);
return;
}
/* If the offset is not a non-negative integer constant that fits
in a HOST_WIDE_INT, we have to fall back to a conservative
solution which includes all sub-fields of all pointed-to
variables of ptr. */
if (offset == NULL_TREE
|| TREE_CODE (offset) != INTEGER_CST)
rhsoffset = UNKNOWN_OFFSET;
else
{
/* Sign-extend the offset. */
offset_int soffset = offset_int::from (wi::to_wide (offset), SIGNED);
if (!wi::fits_shwi_p (soffset))
rhsoffset = UNKNOWN_OFFSET;
else
{
/* Make sure the bit-offset also fits. */
HOST_WIDE_INT rhsunitoffset = soffset.to_shwi ();
rhsoffset = rhsunitoffset * (unsigned HOST_WIDE_INT) BITS_PER_UNIT;
if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
rhsoffset = UNKNOWN_OFFSET;
}
}
get_constraint_for_rhs (ptr, results);
if (rhsoffset == 0)
return;
/* As we are eventually appending to the solution do not use
vec::iterate here. */
n = results->length ();
for (j = 0; j < n; j++)
{
varinfo_t curr;
c = (*results)[j];
curr = get_varinfo (c.var);
if (c.type == ADDRESSOF
/* If this varinfo represents a full variable just use it. */
&& curr->is_full_var)
;
else if (c.type == ADDRESSOF
/* If we do not know the offset add all subfields. */
&& rhsoffset == UNKNOWN_OFFSET)
{
varinfo_t temp = get_varinfo (curr->head);
do
{
struct constraint_expr c2;
c2.var = temp->id;
c2.type = ADDRESSOF;
c2.offset = 0;
if (c2.var != c.var)
results->safe_push (c2);
temp = vi_next (temp);
}
while (temp);
}
else if (c.type == ADDRESSOF)
{
varinfo_t temp;
unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
/* If curr->offset + rhsoffset is less than zero adjust it. */
if (rhsoffset < 0
&& curr->offset < offset)
offset = 0;
/* We have to include all fields that overlap the current
field shifted by rhsoffset. And we include at least
the last or the first field of the variable to represent
reachability of off-bound addresses, in particular &object + 1,
conservatively correct. */
temp = first_or_preceding_vi_for_offset (curr, offset);
c.var = temp->id;
c.offset = 0;
temp = vi_next (temp);
while (temp
&& temp->offset < offset + curr->size)
{
struct constraint_expr c2;
c2.var = temp->id;
c2.type = ADDRESSOF;
c2.offset = 0;
results->safe_push (c2);
temp = vi_next (temp);
}
}
else if (c.type == SCALAR)
{
gcc_assert (c.offset == 0);
c.offset = rhsoffset;
}
else
/* We shouldn't get any DEREFs here. */
gcc_unreachable ();
(*results)[j] = c;
}
}
/* Given a COMPONENT_REF T, return the constraint_expr vector for it.
If address_p is true the result will be taken its address of.
If lhs_p is true then the constraint expression is assumed to be used
as the lhs. */
static void
get_constraint_for_component_ref (tree t, vec<ce_s> *results,
bool address_p, bool lhs_p)
{
tree orig_t = t;
poly_int64 bitsize = -1;
poly_int64 bitmaxsize = -1;
poly_int64 bitpos;
bool reverse;
tree forzero;
/* Some people like to do cute things like take the address of
&0->a.b */
forzero = t;
while (handled_component_p (forzero)
|| INDIRECT_REF_P (forzero)
|| TREE_CODE (forzero) == MEM_REF)
forzero = TREE_OPERAND (forzero, 0);
if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
{
struct constraint_expr temp;
temp.offset = 0;
temp.var = integer_id;
temp.type = SCALAR;
results->safe_push (temp);
return;
}
t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize, &reverse);
/* We can end up here for component references on a
VIEW_CONVERT_EXPR <>(&foobar) or things like a
BIT_FIELD_REF <&MEM[(void *)&b + 4B], ...>. So for
symbolic constants simply give up. */
if (TREE_CODE (t) == ADDR_EXPR)
{
constraint_expr result;
result.type = SCALAR;
result.var = anything_id;
result.offset = 0;
results->safe_push (result);
return;
}
/* Avoid creating pointer-offset constraints, so handle MEM_REF
offsets directly. Pretend to take the address of the base,
we'll take care of adding the required subset of sub-fields below. */
if (TREE_CODE (t) == MEM_REF
&& !integer_zerop (TREE_OPERAND (t, 0)))
{
poly_offset_int off = mem_ref_offset (t);
off <<= LOG2_BITS_PER_UNIT;
off += bitpos;
poly_int64 off_hwi;
if (off.to_shwi (&off_hwi))
bitpos = off_hwi;
else
{
bitpos = 0;
bitmaxsize = -1;
}
get_constraint_for_1 (TREE_OPERAND (t, 0), results, false, lhs_p);
do_deref (results);
}
else
get_constraint_for_1 (t, results, true, lhs_p);
/* Strip off nothing_id. */
if (results->length () == 2)
{
gcc_assert ((*results)[0].var == nothing_id);
results->unordered_remove (0);
}
gcc_assert (results->length () == 1);
struct constraint_expr &result = results->last ();
if (result.type == SCALAR
&& get_varinfo (result.var)->is_full_var)
/* For single-field vars do not bother about the offset. */
result.offset = 0;
else if (result.type == SCALAR)
{
/* In languages like C, you can access one past the end of an
array. You aren't allowed to dereference it, so we can
ignore this constraint. When we handle pointer subtraction,
we may have to do something cute here. */
if (maybe_lt (poly_uint64 (bitpos), get_varinfo (result.var)->fullsize)
&& maybe_ne (bitmaxsize, 0))
{
/* It's also not true that the constraint will actually start at the
right offset, it may start in some padding. We only care about
setting the constraint to the first actual field it touches, so
walk to find it. */
struct constraint_expr cexpr = result;
varinfo_t curr;
results->pop ();
cexpr.offset = 0;
for (curr = get_varinfo (cexpr.var); curr; curr = vi_next (curr))
{
if (ranges_maybe_overlap_p (poly_int64 (curr->offset),
curr->size, bitpos, bitmaxsize))
{
cexpr.var = curr->id;
results->safe_push (cexpr);
if (address_p)
break;
}
}
/* If we are going to take the address of this field then
to be able to compute reachability correctly add at least
the last field of the variable. */
if (address_p && results->length () == 0)
{
curr = get_varinfo (cexpr.var);
while (curr->next != 0)
curr = vi_next (curr);
cexpr.var = curr->id;
results->safe_push (cexpr);
}
else if (results->length () == 0)
/* Assert that we found *some* field there. The user couldn't be
accessing *only* padding. */
/* Still the user could access one past the end of an array
embedded in a struct resulting in accessing *only* padding. */
/* Or accessing only padding via type-punning to a type
that has a filed just in padding space. */
{
cexpr.type = SCALAR;
cexpr.var = anything_id;
cexpr.offset = 0;
results->safe_push (cexpr);
}
}
else if (known_eq (bitmaxsize, 0))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Access to zero-sized part of variable, "
"ignoring\n");
}
else
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Access to past the end of variable, ignoring\n");
}
else if (result.type == DEREF)
{
/* If we do not know exactly where the access goes say so. Note
that only for non-structure accesses we know that we access
at most one subfiled of any variable. */
HOST_WIDE_INT const_bitpos;
if (!bitpos.is_constant (&const_bitpos)
|| const_bitpos == -1
|| maybe_ne (bitsize, bitmaxsize)
|| AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
|| result.offset == UNKNOWN_OFFSET)
result.offset = UNKNOWN_OFFSET;
else
result.offset += const_bitpos;
}
else if (result.type == ADDRESSOF)
{
/* We can end up here for component references on constants like
VIEW_CONVERT_EXPR <>({ 0, 1, 2, 3 })[i]. */
result.type = SCALAR;
result.var = anything_id;
result.offset = 0;
}
else
gcc_unreachable ();
}
/* Dereference the constraint expression CONS, and return the result.
DEREF (ADDRESSOF) = SCALAR
DEREF (SCALAR) = DEREF
DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
This is needed so that we can handle dereferencing DEREF constraints. */
static void
do_deref (vec<ce_s> *constraints)
{
struct constraint_expr *c;
unsigned int i = 0;
FOR_EACH_VEC_ELT (*constraints, i, c)
{
if (c->type == SCALAR)
c->type = DEREF;
else if (c->type == ADDRESSOF)
c->type = SCALAR;
else if (c->type == DEREF)
{
struct constraint_expr tmplhs;
tmplhs = new_scalar_tmp_constraint_exp ("dereftmp", true);
process_constraint (new_constraint (tmplhs, *c));
c->var = tmplhs.var;
}
else
gcc_unreachable ();
}
}
/* Given a tree T, return the constraint expression for taking the
address of it. */
static void
get_constraint_for_address_of (tree t, vec<ce_s> *results)
{
struct constraint_expr *c;
unsigned int i;
get_constraint_for_1 (t, results, true, true);
FOR_EACH_VEC_ELT (*results, i, c)
{
if (c->type == DEREF)
c->type = SCALAR;
else
c->type = ADDRESSOF;
}
}
/* Given a tree T, return the constraint expression for it. */
static void
get_constraint_for_1 (tree t, vec<ce_s> *results, bool address_p,
bool lhs_p)
{
struct constraint_expr temp;
/* x = integer is all glommed to a single variable, which doesn't
point to anything by itself. That is, of course, unless it is an
integer constant being treated as a pointer, in which case, we
will return that this is really the addressof anything. This
happens below, since it will fall into the default case. The only
case we know something about an integer treated like a pointer is
when it is the NULL pointer, and then we just say it points to
NULL.
Do not do that if -fno-delete-null-pointer-checks though, because
in that case *NULL does not fail, so it _should_ alias *anything.
It is not worth adding a new option or renaming the existing one,
since this case is relatively obscure. */
if ((TREE_CODE (t) == INTEGER_CST
&& integer_zerop (t))
/* The only valid CONSTRUCTORs in gimple with pointer typed
elements are zero-initializer. But in IPA mode we also
process global initializers, so verify at least. */
|| (TREE_CODE (t) == CONSTRUCTOR
&& CONSTRUCTOR_NELTS (t) == 0))
{
if (flag_delete_null_pointer_checks)
temp.var = nothing_id;
else
temp.var = nonlocal_id;
temp.type = ADDRESSOF;
temp.offset = 0;
results->safe_push (temp);
return;
}
/* String constants are read-only, ideally we'd have a CONST_DECL
for those. */
if (TREE_CODE (t) == STRING_CST)
{
temp.var = string_id;
temp.type = SCALAR;
temp.offset = 0;
results->safe_push (temp);
return;
}
switch (TREE_CODE_CLASS (TREE_CODE (t)))
{
case tcc_expression:
{
switch (TREE_CODE (t))
{
case ADDR_EXPR:
get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
return;
default:;
}
break;
}
case tcc_reference:
{
switch (TREE_CODE (t))
{
case MEM_REF:
{
struct constraint_expr cs;
varinfo_t vi, curr;
get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
TREE_OPERAND (t, 1), results);
do_deref (results);
/* If we are not taking the address then make sure to process
all subvariables we might access. */
if (address_p)
return;
cs = results->last ();
if (cs.type == DEREF
&& type_can_have_subvars (TREE_TYPE (t)))
{
/* For dereferences this means we have to defer it
to solving time. */
results->last ().offset = UNKNOWN_OFFSET;
return;
}
if (cs.type != SCALAR)
return;
vi = get_varinfo (cs.var);
curr = vi_next (vi);
if (!vi->is_full_var
&& curr)
{
unsigned HOST_WIDE_INT size;
if (tree_fits_uhwi_p (TYPE_SIZE (TREE_TYPE (t))))
size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (t)));
else
size = -1;
for (; curr; curr = vi_next (curr))
{
if (curr->offset - vi->offset < size)
{
cs.var = curr->id;
results->safe_push (cs);
}
else
break;
}
}
return;
}
case ARRAY_REF:
case ARRAY_RANGE_REF:
case COMPONENT_REF:
case IMAGPART_EXPR:
case REALPART_EXPR:
case BIT_FIELD_REF:
get_constraint_for_component_ref (t, results, address_p, lhs_p);
return;
case VIEW_CONVERT_EXPR:
get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
lhs_p);
return;
/* We are missing handling for TARGET_MEM_REF here. */
default:;
}
break;
}
case tcc_exceptional:
{
switch (TREE_CODE (t))
{
case SSA_NAME:
{
get_constraint_for_ssa_var (t, results, address_p);
return;
}
case CONSTRUCTOR:
{
unsigned int i;
tree val;
auto_vec<ce_s> tmp;
FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
{
struct constraint_expr *rhsp;
unsigned j;
get_constraint_for_1 (val, &tmp, address_p, lhs_p);
FOR_EACH_VEC_ELT (tmp, j, rhsp)
results->safe_push (*rhsp);
tmp.truncate (0);
}
/* We do not know whether the constructor was complete,
so technically we have to add &NOTHING or &ANYTHING
like we do for an empty constructor as well. */
return;
}
default:;
}
break;
}
case tcc_declaration:
{
get_constraint_for_ssa_var (t, results, address_p);
return;
}
case tcc_constant:
{
/* We cannot refer to automatic variables through constants. */
temp.type = ADDRESSOF;
temp.var = nonlocal_id;
temp.offset = 0;
results->safe_push (temp);
return;
}
default:;
}
/* The default fallback is a constraint from anything. */
temp.type = ADDRESSOF;
temp.var = anything_id;
temp.offset = 0;
results->safe_push (temp);
}
/* Given a gimple tree T, return the constraint expression vector for it. */
static void
get_constraint_for (tree t, vec<ce_s> *results)
{
gcc_assert (results->length () == 0);
get_constraint_for_1 (t, results, false, true);
}
/* Given a gimple tree T, return the constraint expression vector for it
to be used as the rhs of a constraint. */
static void
get_constraint_for_rhs (tree t, vec<ce_s> *results)
{
gcc_assert (results->length () == 0);
get_constraint_for_1 (t, results, false, false);
}
/* Efficiently generates constraints from all entries in *RHSC to all
entries in *LHSC. */
static void
process_all_all_constraints (const vec<ce_s> &lhsc,
const vec<ce_s> &rhsc)
{
struct constraint_expr *lhsp, *rhsp;
unsigned i, j;
if (lhsc.length () <= 1 || rhsc.length () <= 1)
{
FOR_EACH_VEC_ELT (lhsc, i, lhsp)
FOR_EACH_VEC_ELT (rhsc, j, rhsp)
process_constraint (new_constraint (*lhsp, *rhsp));
}
else
{
struct constraint_expr tmp;
tmp = new_scalar_tmp_constraint_exp ("allalltmp", true);
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (tmp, *rhsp));
FOR_EACH_VEC_ELT (lhsc, i, lhsp)
process_constraint (new_constraint (*lhsp, tmp));
}
}
/* Handle aggregate copies by expanding into copies of the respective
fields of the structures. */
static void
do_structure_copy (tree lhsop, tree rhsop)
{
struct constraint_expr *lhsp, *rhsp;
auto_vec<ce_s> lhsc;
auto_vec<ce_s> rhsc;
unsigned j;
get_constraint_for (lhsop, &lhsc);
get_constraint_for_rhs (rhsop, &rhsc);
lhsp = &lhsc[0];
rhsp = &rhsc[0];
if (lhsp->type == DEREF
|| (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
|| rhsp->type == DEREF)
{
if (lhsp->type == DEREF)
{
gcc_assert (lhsc.length () == 1);
lhsp->offset = UNKNOWN_OFFSET;
}
if (rhsp->type == DEREF)
{
gcc_assert (rhsc.length () == 1);
rhsp->offset = UNKNOWN_OFFSET;
}
process_all_all_constraints (lhsc, rhsc);
}
else if (lhsp->type == SCALAR
&& (rhsp->type == SCALAR
|| rhsp->type == ADDRESSOF))
{
HOST_WIDE_INT lhssize, lhsoffset;
HOST_WIDE_INT rhssize, rhsoffset;
bool reverse;
unsigned k = 0;
if (!get_ref_base_and_extent_hwi (lhsop, &lhsoffset, &lhssize, &reverse)
|| !get_ref_base_and_extent_hwi (rhsop, &rhsoffset, &rhssize,
&reverse))
{
process_all_all_constraints (lhsc, rhsc);
return;
}
for (j = 0; lhsc.iterate (j, &lhsp);)
{
varinfo_t lhsv, rhsv;
rhsp = &rhsc[k];
lhsv = get_varinfo (lhsp->var);
rhsv = get_varinfo (rhsp->var);
if (lhsv->may_have_pointers
&& (lhsv->is_full_var
|| rhsv->is_full_var
|| ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
rhsv->offset + lhsoffset, rhsv->size)))
process_constraint (new_constraint (*lhsp, *rhsp));
if (!rhsv->is_full_var
&& (lhsv->is_full_var
|| (lhsv->offset + rhsoffset + lhsv->size
> rhsv->offset + lhsoffset + rhsv->size)))
{
++k;
if (k >= rhsc.length ())
break;
}
else
++j;
}
}
else
gcc_unreachable ();
}
/* Create constraints ID = { rhsc }. */
static void
make_constraints_to (unsigned id, const vec<ce_s> &rhsc)
{
struct constraint_expr *c;
struct constraint_expr includes;
unsigned int j;
includes.var = id;
includes.offset = 0;
includes.type = SCALAR;
FOR_EACH_VEC_ELT (rhsc, j, c)
process_constraint (new_constraint (includes, *c));
}
/* Create a constraint ID = OP. */
static void
make_constraint_to (unsigned id, tree op)
{
auto_vec<ce_s> rhsc;
get_constraint_for_rhs (op, &rhsc);
make_constraints_to (id, rhsc);
}
/* Create a constraint ID = &FROM. */
static void
make_constraint_from (varinfo_t vi, int from)
{
struct constraint_expr lhs, rhs;
lhs.var = vi->id;
lhs.offset = 0;
lhs.type = SCALAR;
rhs.var = from;
rhs.offset = 0;
rhs.type = ADDRESSOF;
process_constraint (new_constraint (lhs, rhs));
}
/* Create a constraint ID = FROM. */
static void
make_copy_constraint (varinfo_t vi, int from)
{
struct constraint_expr lhs, rhs;
lhs.var = vi->id;
lhs.offset = 0;
lhs.type = SCALAR;
rhs.var = from;
rhs.offset = 0;
rhs.type = SCALAR;
process_constraint (new_constraint (lhs, rhs));
}
/* Make constraints necessary to make OP escape. */
static void
make_escape_constraint (tree op)
{
make_constraint_to (escaped_id, op);
}
/* Make constraint necessary to make all indirect references
from VI escape. */
static void
make_indirect_escape_constraint (varinfo_t vi)
{
struct constraint_expr lhs, rhs;
/* escaped = *(VAR + UNKNOWN); */
lhs.type = SCALAR;
lhs.var = escaped_id;
lhs.offset = 0;
rhs.type = DEREF;
rhs.var = vi->id;
rhs.offset = UNKNOWN_OFFSET;
process_constraint (new_constraint (lhs, rhs));
}
/* Add constraints to that the solution of VI is transitively closed. */
static void
make_transitive_closure_constraints (varinfo_t vi)
{
struct constraint_expr lhs, rhs;
/* VAR = *(VAR + UNKNOWN); */
lhs.type = SCALAR;
lhs.var = vi->id;
lhs.offset = 0;
rhs.type = DEREF;
rhs.var = vi->id;
rhs.offset = UNKNOWN_OFFSET;
process_constraint (new_constraint (lhs, rhs));
}
/* Add constraints to that the solution of VI has all subvariables added. */
static void
make_any_offset_constraints (varinfo_t vi)
{
struct constraint_expr lhs, rhs;
/* VAR = VAR + UNKNOWN; */
lhs.type = SCALAR;
lhs.var = vi->id;
lhs.offset = 0;
rhs.type = SCALAR;
rhs.var = vi->id;
rhs.offset = UNKNOWN_OFFSET;
process_constraint (new_constraint (lhs, rhs));
}
/* Temporary storage for fake var decls. */
struct obstack fake_var_decl_obstack;
/* Build a fake VAR_DECL acting as referrer to a DECL_UID. */
static tree
build_fake_var_decl (tree type)
{
tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct tree_var_decl);
memset (decl, 0, sizeof (struct tree_var_decl));
TREE_SET_CODE (decl, VAR_DECL);
TREE_TYPE (decl) = type;
DECL_UID (decl) = allocate_decl_uid ();
SET_DECL_PT_UID (decl, -1);
layout_decl (decl, 0);
return decl;
}
/* Create a new artificial heap variable with NAME.
Return the created variable. */
static varinfo_t
make_heapvar (const char *name, bool add_id)
{
varinfo_t vi;
tree heapvar;
heapvar = build_fake_var_decl (ptr_type_node);
DECL_EXTERNAL (heapvar) = 1;
vi = new_var_info (heapvar, name, add_id);
vi->is_heap_var = true;
vi->is_unknown_size_var = true;
vi->offset = 0;
vi->fullsize = ~0;
vi->size = ~0;
vi->is_full_var = true;
insert_vi_for_tree (heapvar, vi);
return vi;
}
/* Create a new artificial heap variable with NAME and make a
constraint from it to LHS. Set flags according to a tag used
for tracking restrict pointers. */
static varinfo_t
make_constraint_from_restrict (varinfo_t lhs, const char *name, bool add_id)
{
varinfo_t vi = make_heapvar (name, add_id);
vi->is_restrict_var = 1;
vi->is_global_var = 1;
vi->may_have_pointers = 1;
make_constraint_from (lhs, vi->id);
return vi;
}
/* Create a new artificial heap variable with NAME and make a
constraint from it to LHS. Set flags according to a tag used
for tracking restrict pointers and make the artificial heap
point to global memory. */
static varinfo_t
make_constraint_from_global_restrict (varinfo_t lhs, const char *name,
bool add_id)
{
varinfo_t vi = make_constraint_from_restrict (lhs, name, add_id);
make_copy_constraint (vi, nonlocal_id);
return vi;
}
/* In IPA mode there are varinfos for different aspects of reach
function designator. One for the points-to set of the return
value, one for the variables that are clobbered by the function,
one for its uses and one for each parameter (including a single
glob for remaining variadic arguments). */
enum { fi_clobbers = 1, fi_uses = 2,
fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
/* Get a constraint for the requested part of a function designator FI
when operating in IPA mode. */
static struct constraint_expr
get_function_part_constraint (varinfo_t fi, unsigned part)
{
struct constraint_expr c;
gcc_assert (in_ipa_mode);
if (fi->id == anything_id)
{
/* ??? We probably should have a ANYFN special variable. */
c.var = anything_id;
c.offset = 0;
c.type = SCALAR;
}
else if (fi->decl && TREE_CODE (fi->decl) == FUNCTION_DECL)
{
varinfo_t ai = first_vi_for_offset (fi, part);
if (ai)
c.var = ai->id;
else
c.var = anything_id;
c.offset = 0;
c.type = SCALAR;
}
else
{
c.var = fi->id;
c.offset = part;
c.type = DEREF;
}
return c;
}
/* Produce constraints for argument ARG of call STMT with eaf flags
FLAGS. RESULTS is array holding constraints for return value.
CALLESCAPE_ID is variable where call loocal escapes are added.
WRITES_GLOVEL_MEMORY is true if callee may write global memory. */
static void
handle_call_arg (gcall *stmt, tree arg, vec<ce_s> *results, int flags,
int callescape_id, bool writes_global_memory)
{
int relevant_indirect_flags = EAF_NO_INDIRECT_CLOBBER | EAF_NO_INDIRECT_READ
| EAF_NO_INDIRECT_ESCAPE;
int relevant_flags = relevant_indirect_flags
| EAF_NO_DIRECT_CLOBBER
| EAF_NO_DIRECT_READ
| EAF_NO_DIRECT_ESCAPE;
if (gimple_call_lhs (stmt))
{
relevant_flags |= EAF_NOT_RETURNED_DIRECTLY | EAF_NOT_RETURNED_INDIRECTLY;
relevant_indirect_flags |= EAF_NOT_RETURNED_INDIRECTLY;
/* If value is never read from it can not be returned indirectly
(except through the escape solution).
For all flags we get these implications right except for
not_returned because we miss return functions in ipa-prop. */
if (flags & EAF_NO_DIRECT_READ)
flags |= EAF_NOT_RETURNED_INDIRECTLY;
}
/* If the argument is not used we can ignore it.
Similarly argument is invisile for us if it not clobbered, does not
escape, is not read and can not be returned. */
if ((flags & EAF_UNUSED) || ((flags & relevant_flags) == relevant_flags))
return;
/* Produce varinfo for direct accesses to ARG. */
varinfo_t tem = new_var_info (NULL_TREE, "callarg", true);
tem->is_reg_var = true;
make_constraint_to (tem->id, arg);
make_any_offset_constraints (tem);
bool callarg_transitive = false;
/* As an compile time optimization if we make no difference between
direct and indirect accesses make arg transitively closed.
This avoids the need to build indir arg and do everything twice. */
if (((flags & EAF_NO_INDIRECT_CLOBBER) != 0)
== ((flags & EAF_NO_DIRECT_CLOBBER) != 0)
&& (((flags & EAF_NO_INDIRECT_READ) != 0)
== ((flags & EAF_NO_DIRECT_READ) != 0))
&& (((flags & EAF_NO_INDIRECT_ESCAPE) != 0)
== ((flags & EAF_NO_DIRECT_ESCAPE) != 0))
&& (((flags & EAF_NOT_RETURNED_INDIRECTLY) != 0)
== ((flags & EAF_NOT_RETURNED_DIRECTLY) != 0)))
{
make_transitive_closure_constraints (tem);
callarg_transitive = true;
gcc_checking_assert (!(flags & EAF_NO_DIRECT_READ));
}
/* If necessary, produce varinfo for indirect accesses to ARG. */
varinfo_t indir_tem = NULL;
if (!callarg_transitive
&& (flags & relevant_indirect_flags) != relevant_indirect_flags)
{
struct constraint_expr lhs, rhs;
indir_tem = new_var_info (NULL_TREE, "indircallarg", true);
indir_tem->is_reg_var = true;
/* indir_term = *tem. */
lhs.type = SCALAR;
lhs.var = indir_tem->id;
lhs.offset = 0;
rhs.type = DEREF;
rhs.var = tem->id;
rhs.offset = UNKNOWN_OFFSET;
process_constraint (new_constraint (lhs, rhs));
make_any_offset_constraints (indir_tem);
/* If we do not read indirectly there is no need for transitive closure.
We know there is only one level of indirection. */
if (!(flags & EAF_NO_INDIRECT_READ))
make_transitive_closure_constraints (indir_tem);
gcc_checking_assert (!(flags & EAF_NO_DIRECT_READ));
}
if (gimple_call_lhs (stmt))
{
if (!(flags & EAF_NOT_RETURNED_DIRECTLY))
{
struct constraint_expr cexpr;
cexpr.var = tem->id;
cexpr.type = SCALAR;
cexpr.offset = 0;
results->safe_push (cexpr);
}
if (!callarg_transitive & !(flags & EAF_NOT_RETURNED_INDIRECTLY))
{
struct constraint_expr cexpr;
cexpr.var = indir_tem->id;
cexpr.type = SCALAR;
cexpr.offset = 0;
results->safe_push (cexpr);
}
}
if (!(flags & EAF_NO_DIRECT_READ))
{
varinfo_t uses = get_call_use_vi (stmt);
make_copy_constraint (uses, tem->id);
if (!callarg_transitive & !(flags & EAF_NO_INDIRECT_READ))
make_copy_constraint (uses, indir_tem->id);
}
else
/* To read indirectly we need to read directly. */
gcc_checking_assert (flags & EAF_NO_INDIRECT_READ);
if (!(flags & EAF_NO_DIRECT_CLOBBER))
{
struct constraint_expr lhs, rhs;
/* *arg = callescape. */
lhs.type = DEREF;
lhs.var = tem->id;
lhs.offset = 0;
rhs.type = SCALAR;
rhs.var = callescape_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
/* callclobbered = arg. */
make_copy_constraint (get_call_clobber_vi (stmt), tem->id);
}
if (!callarg_transitive & !(flags & EAF_NO_INDIRECT_CLOBBER))
{
struct constraint_expr lhs, rhs;
/* *indir_arg = callescape. */
lhs.type = DEREF;
lhs.var = indir_tem->id;
lhs.offset = 0;
rhs.type = SCALAR;
rhs.var = callescape_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
/* callclobbered = indir_arg. */
make_copy_constraint (get_call_clobber_vi (stmt), indir_tem->id);
}
if (!(flags & (EAF_NO_DIRECT_ESCAPE | EAF_NO_INDIRECT_ESCAPE)))
{
struct constraint_expr lhs, rhs;
/* callescape = arg; */
lhs.var = callescape_id;
lhs.offset = 0;
lhs.type = SCALAR;
rhs.var = tem->id;
rhs.offset = 0;
rhs.type = SCALAR;
process_constraint (new_constraint (lhs, rhs));
if (writes_global_memory)
make_escape_constraint (arg);
}
else if (!callarg_transitive & !(flags & EAF_NO_INDIRECT_ESCAPE))
{
struct constraint_expr lhs, rhs;
/* callescape = *(indir_arg + UNKNOWN); */
lhs.var = callescape_id;
lhs.offset = 0;
lhs.type = SCALAR;
rhs.var = indir_tem->id;
rhs.offset = 0;
rhs.type = SCALAR;
process_constraint (new_constraint (lhs, rhs));
if (writes_global_memory)
make_indirect_escape_constraint (tem);
}
}
/* Determine global memory access of call STMT and update
WRITES_GLOBAL_MEMORY, READS_GLOBAL_MEMORY and USES_GLOBAL_MEMORY. */
static void
determine_global_memory_access (gcall *stmt,
bool *writes_global_memory,
bool *reads_global_memory,
bool *uses_global_memory)
{
tree callee;
cgraph_node *node;
modref_summary *summary;
/* We need to detrmine reads to set uses. */
gcc_assert (!uses_global_memory || reads_global_memory);
if ((callee = gimple_call_fndecl (stmt)) != NULL_TREE
&& (node = cgraph_node::get (callee)) != NULL
&& (summary = get_modref_function_summary (node)))
{
if (writes_global_memory && *writes_global_memory)
*writes_global_memory = summary->global_memory_written;
if (reads_global_memory && *reads_global_memory)
*reads_global_memory = summary->global_memory_read;
if (reads_global_memory && uses_global_memory
&& !summary->calls_interposable
&& !*reads_global_memory && node->binds_to_current_def_p ())
*uses_global_memory = false;
}
if ((writes_global_memory && *writes_global_memory)
|| (uses_global_memory && *uses_global_memory)
|| (reads_global_memory && *reads_global_memory))
{
attr_fnspec fnspec = gimple_call_fnspec (stmt);
if (fnspec.known_p ())
{
if (writes_global_memory
&& !fnspec.global_memory_written_p ())
*writes_global_memory = false;
if (reads_global_memory && !fnspec.global_memory_read_p ())
{
*reads_global_memory = false;
if (uses_global_memory)
*uses_global_memory = false;
}
}
}
}
/* For non-IPA mode, generate constraints necessary for a call on the
RHS and collect return value constraint to RESULTS to be used later in
handle_lhs_call.
IMPLICIT_EAF_FLAGS are added to each function argument. If
WRITES_GLOBAL_MEMORY is true function is assumed to possibly write to global
memory. Similar for READS_GLOBAL_MEMORY. */
static void
handle_rhs_call (gcall *stmt, vec<ce_s> *results,
int implicit_eaf_flags,
bool writes_global_memory,
bool reads_global_memory)
{
determine_global_memory_access (stmt, &writes_global_memory,
&reads_global_memory,
NULL);
varinfo_t callescape = new_var_info (NULL_TREE, "callescape", true);
/* If function can use global memory, add it to callescape
and to possible return values. If not we can still use/return addresses
of global symbols. */
struct constraint_expr lhs, rhs;
lhs.type = SCALAR;
lhs.var = callescape->id;
lhs.offset = 0;
rhs.type = reads_global_memory ? SCALAR : ADDRESSOF;
rhs.var = nonlocal_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
results->safe_push (rhs);
varinfo_t uses = get_call_use_vi (stmt);
make_copy_constraint (uses, callescape->id);
for (unsigned i = 0; i < gimple_call_num_args (stmt); ++i)
{
tree arg = gimple_call_arg (stmt, i);
int flags = gimple_call_arg_flags (stmt, i);
handle_call_arg (stmt, arg, results,
flags | implicit_eaf_flags,
callescape->id, writes_global_memory);
}
/* The static chain escapes as well. */
if (gimple_call_chain (stmt))
handle_call_arg (stmt, gimple_call_chain (stmt), results,
implicit_eaf_flags
| gimple_call_static_chain_flags (stmt),
callescape->id, writes_global_memory);
/* And if we applied NRV the address of the return slot escapes as well. */
if (gimple_call_return_slot_opt_p (stmt)
&& gimple_call_lhs (stmt) != NULL_TREE
&& TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
{
int flags = gimple_call_retslot_flags (stmt);
const int relevant_flags = EAF_NO_DIRECT_ESCAPE
| EAF_NOT_RETURNED_DIRECTLY;
if (!(flags & EAF_UNUSED) && (flags & relevant_flags) != relevant_flags)
{
auto_vec<ce_s> tmpc;
get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
if (!(flags & EAF_NO_DIRECT_ESCAPE))
{
make_constraints_to (callescape->id, tmpc);
if (writes_global_memory)
make_constraints_to (escaped_id, tmpc);
}
if (!(flags & EAF_NOT_RETURNED_DIRECTLY))
{
struct constraint_expr *c;
unsigned i;
FOR_EACH_VEC_ELT (tmpc, i, c)
results->safe_push (*c);
}
}
}
}
/* For non-IPA mode, generate constraints necessary for a call
that returns a pointer and assigns it to LHS. This simply makes
the LHS point to global and escaped variables. */
static void
handle_lhs_call (gcall *stmt, tree lhs, int flags, vec<ce_s> &rhsc,
tree fndecl)
{
auto_vec<ce_s> lhsc;
get_constraint_for (lhs, &lhsc);
/* If the store is to a global decl make sure to
add proper escape constraints. */
lhs = get_base_address (lhs);
if (lhs
&& DECL_P (lhs)
&& is_global_var (lhs))
{
struct constraint_expr tmpc;
tmpc.var = escaped_id;
tmpc.offset = 0;
tmpc.type = SCALAR;
lhsc.safe_push (tmpc);
}
/* If the call returns an argument unmodified override the rhs
constraints. */
if (flags & ERF_RETURNS_ARG
&& (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
{
tree arg;
rhsc.create (0);
arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
get_constraint_for (arg, &rhsc);
process_all_all_constraints (lhsc, rhsc);
rhsc.release ();
}
else if (flags & ERF_NOALIAS)
{
varinfo_t vi;
struct constraint_expr tmpc;
rhsc.create (0);
vi = make_heapvar ("HEAP", true);
/* We are marking allocated storage local, we deal with it becoming
global by escaping and setting of vars_contains_escaped_heap. */
DECL_EXTERNAL (vi->decl) = 0;
vi->is_global_var = 0;
/* If this is not a real malloc call assume the memory was
initialized and thus may point to global memory. All
builtin functions with the malloc attribute behave in a sane way. */
if (!fndecl
|| !fndecl_built_in_p (fndecl, BUILT_IN_NORMAL))
make_constraint_from (vi, nonlocal_id);
tmpc.var = vi->id;
tmpc.offset = 0;
tmpc.type = ADDRESSOF;
rhsc.safe_push (tmpc);
process_all_all_constraints (lhsc, rhsc);
rhsc.release ();
}
else
process_all_all_constraints (lhsc, rhsc);
}
/* Return the varinfo for the callee of CALL. */
static varinfo_t
get_fi_for_callee (gcall *call)
{
tree decl, fn = gimple_call_fn (call);
if (fn && TREE_CODE (fn) == OBJ_TYPE_REF)
fn = OBJ_TYPE_REF_EXPR (fn);
/* If we can directly resolve the function being called, do so.
Otherwise, it must be some sort of indirect expression that
we should still be able to handle. */
decl = gimple_call_addr_fndecl (fn);
if (decl)
return get_vi_for_tree (decl);
/* If the function is anything other than a SSA name pointer we have no
clue and should be getting ANYFN (well, ANYTHING for now). */
if (!fn || TREE_CODE (fn) != SSA_NAME)
return get_varinfo (anything_id);
if (SSA_NAME_IS_DEFAULT_DEF (fn)
&& (TREE_CODE (SSA_NAME_VAR (fn)) == PARM_DECL
|| TREE_CODE (SSA_NAME_VAR (fn)) == RESULT_DECL))
fn = SSA_NAME_VAR (fn);
return get_vi_for_tree (fn);
}
/* Create constraints for assigning call argument ARG to the incoming parameter
INDEX of function FI. */
static void
find_func_aliases_for_call_arg (varinfo_t fi, unsigned index, tree arg)
{
struct constraint_expr lhs;
lhs = get_function_part_constraint (fi, fi_parm_base + index);
auto_vec<ce_s, 2> rhsc;
get_constraint_for_rhs (arg, &rhsc);
unsigned j;
struct constraint_expr *rhsp;
FOR_EACH_VEC_ELT (rhsc, j, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
}
/* Return true if FNDECL may be part of another lto partition. */
static bool
fndecl_maybe_in_other_partition (tree fndecl)
{
cgraph_node *fn_node = cgraph_node::get (fndecl);
if (fn_node == NULL)
return true;
return fn_node->in_other_partition;
}
/* Create constraints for the builtin call T. Return true if the call
was handled, otherwise false. */
static bool
find_func_aliases_for_builtin_call (struct function *fn, gcall *t)
{
tree fndecl = gimple_call_fndecl (t);
auto_vec<ce_s, 2> lhsc;
auto_vec<ce_s, 4> rhsc;
varinfo_t fi;
if (gimple_call_builtin_p (t, BUILT_IN_NORMAL))
/* ??? All builtins that are handled here need to be handled
in the alias-oracle query functions explicitly! */
switch (DECL_FUNCTION_CODE (fndecl))
{
/* All the following functions return a pointer to the same object
as their first argument points to. The functions do not add
to the ESCAPED solution. The functions make the first argument
pointed to memory point to what the second argument pointed to
memory points to. */
case BUILT_IN_STRCPY:
case BUILT_IN_STRNCPY:
case BUILT_IN_BCOPY:
case BUILT_IN_MEMCPY:
case BUILT_IN_MEMMOVE:
case BUILT_IN_MEMPCPY:
case BUILT_IN_STPCPY:
case BUILT_IN_STPNCPY:
case BUILT_IN_STRCAT:
case BUILT_IN_STRNCAT:
case BUILT_IN_STRCPY_CHK:
case BUILT_IN_STRNCPY_CHK:
case BUILT_IN_MEMCPY_CHK:
case BUILT_IN_MEMMOVE_CHK:
case BUILT_IN_MEMPCPY_CHK:
case BUILT_IN_STPCPY_CHK:
case BUILT_IN_STPNCPY_CHK:
case BUILT_IN_STRCAT_CHK:
case BUILT_IN_STRNCAT_CHK:
case BUILT_IN_TM_MEMCPY:
case BUILT_IN_TM_MEMMOVE:
{
tree res = gimple_call_lhs (t);
tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
== BUILT_IN_BCOPY ? 1 : 0));
tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
== BUILT_IN_BCOPY ? 0 : 1));
if (res != NULL_TREE)
{
get_constraint_for (res, &lhsc);
if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
|| DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
|| DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY
|| DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY_CHK
|| DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY_CHK
|| DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY_CHK)
get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
else
get_constraint_for (dest, &rhsc);
process_all_all_constraints (lhsc, rhsc);
lhsc.truncate (0);
rhsc.truncate (0);
}
get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
do_deref (&lhsc);
do_deref (&rhsc);
process_all_all_constraints (lhsc, rhsc);
return true;
}
case BUILT_IN_MEMSET:
case BUILT_IN_MEMSET_CHK:
case BUILT_IN_TM_MEMSET:
{
tree res = gimple_call_lhs (t);
tree dest = gimple_call_arg (t, 0);
unsigned i;
ce_s *lhsp;
struct constraint_expr ac;
if (res != NULL_TREE)
{
get_constraint_for (res, &lhsc);
get_constraint_for (dest, &rhsc);
process_all_all_constraints (lhsc, rhsc);
lhsc.truncate (0);
}
get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
do_deref (&lhsc);
if (flag_delete_null_pointer_checks
&& integer_zerop (gimple_call_arg (t, 1)))
{
ac.type = ADDRESSOF;
ac.var = nothing_id;
}
else
{
ac.type = SCALAR;
ac.var = integer_id;
}
ac.offset = 0;
FOR_EACH_VEC_ELT (lhsc, i, lhsp)
process_constraint (new_constraint (*lhsp, ac));
return true;
}
case BUILT_IN_STACK_SAVE:
case BUILT_IN_STACK_RESTORE:
/* Nothing interesting happens. */
return true;
case BUILT_IN_ALLOCA:
case BUILT_IN_ALLOCA_WITH_ALIGN:
case BUILT_IN_ALLOCA_WITH_ALIGN_AND_MAX:
{
tree ptr = gimple_call_lhs (t);
if (ptr == NULL_TREE)
return true;
get_constraint_for (ptr, &lhsc);
varinfo_t vi = make_heapvar ("HEAP", true);
/* Alloca storage is never global. To exempt it from escaped
handling make it a non-heap var. */
DECL_EXTERNAL (vi->decl) = 0;
vi->is_global_var = 0;
vi->is_heap_var = 0;
struct constraint_expr tmpc;
tmpc.var = vi->id;
tmpc.offset = 0;
tmpc.type = ADDRESSOF;
rhsc.safe_push (tmpc);
process_all_all_constraints (lhsc, rhsc);
return true;
}
case BUILT_IN_POSIX_MEMALIGN:
{
tree ptrptr = gimple_call_arg (t, 0);
get_constraint_for (ptrptr, &lhsc);
do_deref (&lhsc);
varinfo_t vi = make_heapvar ("HEAP", true);
/* We are marking allocated storage local, we deal with it becoming
global by escaping and setting of vars_contains_escaped_heap. */
DECL_EXTERNAL (vi->decl) = 0;
vi->is_global_var = 0;
struct constraint_expr tmpc;
tmpc.var = vi->id;
tmpc.offset = 0;
tmpc.type = ADDRESSOF;
rhsc.safe_push (tmpc);
process_all_all_constraints (lhsc, rhsc);
return true;
}
case BUILT_IN_ASSUME_ALIGNED:
{
tree res = gimple_call_lhs (t);
tree dest = gimple_call_arg (t, 0);
if (res != NULL_TREE)
{
get_constraint_for (res, &lhsc);
get_constraint_for (dest, &rhsc);
process_all_all_constraints (lhsc, rhsc);
}
return true;
}
/* All the following functions do not return pointers, do not
modify the points-to sets of memory reachable from their
arguments and do not add to the ESCAPED solution. */
case BUILT_IN_SINCOS:
case BUILT_IN_SINCOSF:
case BUILT_IN_SINCOSL:
case BUILT_IN_FREXP:
case BUILT_IN_FREXPF:
case BUILT_IN_FREXPL:
case BUILT_IN_GAMMA_R:
case BUILT_IN_GAMMAF_R:
case BUILT_IN_GAMMAL_R:
case BUILT_IN_LGAMMA_R:
case BUILT_IN_LGAMMAF_R:
case BUILT_IN_LGAMMAL_R:
case BUILT_IN_MODF:
case BUILT_IN_MODFF:
case BUILT_IN_MODFL:
case BUILT_IN_REMQUO:
case BUILT_IN_REMQUOF:
case BUILT_IN_REMQUOL:
case BUILT_IN_FREE:
return true;
case BUILT_IN_STRDUP:
case BUILT_IN_STRNDUP:
case BUILT_IN_REALLOC:
if (gimple_call_lhs (t))
{
auto_vec<ce_s> rhsc;
handle_lhs_call (t, gimple_call_lhs (t),
gimple_call_return_flags (t) | ERF_NOALIAS,
rhsc, fndecl);
get_constraint_for_ptr_offset (gimple_call_lhs (t),
NULL_TREE, &lhsc);
get_constraint_for_ptr_offset (gimple_call_arg (t, 0),
NULL_TREE, &rhsc);
do_deref (&lhsc);
do_deref (&rhsc);
process_all_all_constraints (lhsc, rhsc);
lhsc.truncate (0);
rhsc.truncate (0);
/* For realloc the resulting pointer can be equal to the
argument as well. But only doing this wouldn't be
correct because with ptr == 0 realloc behaves like malloc. */
if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_REALLOC)
{
get_constraint_for (gimple_call_lhs (t), &lhsc);
get_constraint_for (gimple_call_arg (t, 0), &rhsc);
process_all_all_constraints (lhsc, rhsc);
}
return true;
}
break;
/* String / character search functions return a pointer into the
source string or NULL. */
case BUILT_IN_INDEX:
case BUILT_IN_STRCHR:
case BUILT_IN_STRRCHR:
case BUILT_IN_MEMCHR:
case BUILT_IN_STRSTR:
case BUILT_IN_STRPBRK:
if (gimple_call_lhs (t))
{
tree src = gimple_call_arg (t, 0);
get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
constraint_expr nul;
nul.var = nothing_id;
nul.offset = 0;
nul.type = ADDRESSOF;
rhsc.safe_push (nul);
get_constraint_for (gimple_call_lhs (t), &lhsc);
process_all_all_constraints (lhsc, rhsc);
}
return true;
/* Pure functions that return something not based on any object and
that use the memory pointed to by their arguments (but not
transitively). */
case BUILT_IN_STRCMP:
case BUILT_IN_STRCMP_EQ:
case BUILT_IN_STRNCMP:
case BUILT_IN_STRNCMP_EQ:
case BUILT_IN_STRCASECMP:
case BUILT_IN_STRNCASECMP:
case BUILT_IN_MEMCMP:
case BUILT_IN_BCMP:
case BUILT_IN_STRSPN:
case BUILT_IN_STRCSPN:
{
varinfo_t uses = get_call_use_vi (t);
make_any_offset_constraints (uses);
make_constraint_to (uses->id, gimple_call_arg (t, 0));
make_constraint_to (uses->id, gimple_call_arg (t, 1));
/* No constraints are necessary for the return value. */
return true;
}
case BUILT_IN_STRLEN:
{
varinfo_t uses = get_call_use_vi (t);
make_any_offset_constraints (uses);
make_constraint_to (uses->id, gimple_call_arg (t, 0));
/* No constraints are necessary for the return value. */
return true;
}
case BUILT_IN_OBJECT_SIZE:
case BUILT_IN_CONSTANT_P:
{
/* No constraints are necessary for the return value or the
arguments. */
return true;
}
/* Trampolines are special - they set up passing the static
frame. */
case BUILT_IN_INIT_TRAMPOLINE:
{
tree tramp = gimple_call_arg (t, 0);
tree nfunc = gimple_call_arg (t, 1);
tree frame = gimple_call_arg (t, 2);
unsigned i;
struct constraint_expr lhs, *rhsp;
if (in_ipa_mode)
{
varinfo_t nfi = NULL;
gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
if (nfi)
{
lhs = get_function_part_constraint (nfi, fi_static_chain);
get_constraint_for (frame, &rhsc);
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
rhsc.truncate (0);
/* Make the frame point to the function for
the trampoline adjustment call. */
get_constraint_for (tramp, &lhsc);
do_deref (&lhsc);
get_constraint_for (nfunc, &rhsc);
process_all_all_constraints (lhsc, rhsc);
return true;
}
}
/* Else fallthru to generic handling which will let
the frame escape. */
break;
}
case BUILT_IN_ADJUST_TRAMPOLINE:
{
tree tramp = gimple_call_arg (t, 0);
tree res = gimple_call_lhs (t);
if (in_ipa_mode && res)
{
get_constraint_for (res, &lhsc);
get_constraint_for (tramp, &rhsc);
do_deref (&rhsc);
process_all_all_constraints (lhsc, rhsc);
}
return true;
}
CASE_BUILT_IN_TM_STORE (1):
CASE_BUILT_IN_TM_STORE (2):
CASE_BUILT_IN_TM_STORE (4):
CASE_BUILT_IN_TM_STORE (8):
CASE_BUILT_IN_TM_STORE (FLOAT):
CASE_BUILT_IN_TM_STORE (DOUBLE):
CASE_BUILT_IN_TM_STORE (LDOUBLE):
CASE_BUILT_IN_TM_STORE (M64):
CASE_BUILT_IN_TM_STORE (M128):
CASE_BUILT_IN_TM_STORE (M256):
{
tree addr = gimple_call_arg (t, 0);
tree src = gimple_call_arg (t, 1);
get_constraint_for (addr, &lhsc);
do_deref (&lhsc);
get_constraint_for (src, &rhsc);
process_all_all_constraints (lhsc, rhsc);
return true;
}
CASE_BUILT_IN_TM_LOAD (1):
CASE_BUILT_IN_TM_LOAD (2):
CASE_BUILT_IN_TM_LOAD (4):
CASE_BUILT_IN_TM_LOAD (8):
CASE_BUILT_IN_TM_LOAD (FLOAT):
CASE_BUILT_IN_TM_LOAD (DOUBLE):
CASE_BUILT_IN_TM_LOAD (LDOUBLE):
CASE_BUILT_IN_TM_LOAD (M64):
CASE_BUILT_IN_TM_LOAD (M128):
CASE_BUILT_IN_TM_LOAD (M256):
{
tree dest = gimple_call_lhs (t);
tree addr = gimple_call_arg (t, 0);
get_constraint_for (dest, &lhsc);
get_constraint_for (addr, &rhsc);
do_deref (&rhsc);
process_all_all_constraints (lhsc, rhsc);
return true;
}
/* Variadic argument handling needs to be handled in IPA
mode as well. */
case BUILT_IN_VA_START:
{
tree valist = gimple_call_arg (t, 0);
struct constraint_expr rhs, *lhsp;
unsigned i;
get_constraint_for_ptr_offset (valist, NULL_TREE, &lhsc);
do_deref (&lhsc);
/* The va_list gets access to pointers in variadic
arguments. Which we know in the case of IPA analysis
and otherwise are just all nonlocal variables. */
if (in_ipa_mode)
{
fi = lookup_vi_for_tree (fn->decl);
rhs = get_function_part_constraint (fi, ~0);
rhs.type = ADDRESSOF;
}
else
{
rhs.var = nonlocal_id;
rhs.type = ADDRESSOF;
rhs.offset = 0;
}
FOR_EACH_VEC_ELT (lhsc, i, lhsp)
process_constraint (new_constraint (*lhsp, rhs));
/* va_list is clobbered. */
make_constraint_to (get_call_clobber_vi (t)->id, valist);
return true;
}
/* va_end doesn't have any effect that matters. */
case BUILT_IN_VA_END:
return true;
/* Alternate return. Simply give up for now. */
case BUILT_IN_RETURN:
{
fi = NULL;
if (!in_ipa_mode
|| !(fi = get_vi_for_tree (fn->decl)))
make_constraint_from (get_varinfo (escaped_id), anything_id);
else if (in_ipa_mode
&& fi != NULL)
{
struct constraint_expr lhs, rhs;
lhs = get_function_part_constraint (fi, fi_result);
rhs.var = anything_id;
rhs.offset = 0;
rhs.type = SCALAR;
process_constraint (new_constraint (lhs, rhs));
}
return true;
}
case BUILT_IN_GOMP_PARALLEL:
case BUILT_IN_GOACC_PARALLEL:
{
if (in_ipa_mode)
{
unsigned int fnpos, argpos;
switch (DECL_FUNCTION_CODE (fndecl))
{
case BUILT_IN_GOMP_PARALLEL:
/* __builtin_GOMP_parallel (fn, data, num_threads, flags). */
fnpos = 0;
argpos = 1;
break;
case BUILT_IN_GOACC_PARALLEL:
/* __builtin_GOACC_parallel (flags_m, fn, mapnum, hostaddrs,
sizes, kinds, ...). */
fnpos = 1;
argpos = 3;
break;
default:
gcc_unreachable ();
}
tree fnarg = gimple_call_arg (t, fnpos);
gcc_assert (TREE_CODE (fnarg) == ADDR_EXPR);
tree fndecl = TREE_OPERAND (fnarg, 0);
if (fndecl_maybe_in_other_partition (fndecl))
/* Fallthru to general call handling. */
break;
tree arg = gimple_call_arg (t, argpos);
varinfo_t fi = get_vi_for_tree (fndecl);
find_func_aliases_for_call_arg (fi, 0, arg);
return true;
}
/* Else fallthru to generic call handling. */
break;
}
/* printf-style functions may have hooks to set pointers to
point to somewhere into the generated string. Leave them
for a later exercise... */
default:
/* Fallthru to general call handling. */;
}
return false;
}
/* Create constraints for the call T. */
static void
find_func_aliases_for_call (struct function *fn, gcall *t)
{
tree fndecl = gimple_call_fndecl (t);
varinfo_t fi;
if (fndecl != NULL_TREE
&& fndecl_built_in_p (fndecl)
&& find_func_aliases_for_builtin_call (fn, t))
return;
if (gimple_call_internal_p (t, IFN_DEFERRED_INIT))
return;
fi = get_fi_for_callee (t);
if (!in_ipa_mode
|| (fi->decl && fndecl && !fi->is_fn_info))
{
auto_vec<ce_s, 16> rhsc;
int flags = gimple_call_flags (t);
/* Const functions can return their arguments and addresses
of global memory but not of escaped memory. */
if (flags & (ECF_CONST|ECF_NOVOPS))
{
if (gimple_call_lhs (t))
handle_rhs_call (t, &rhsc, implicit_const_eaf_flags, false, false);
}
/* Pure functions can return addresses in and of memory
reachable from their arguments, but they are not an escape
point for reachable memory of their arguments. */
else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
handle_rhs_call (t, &rhsc, implicit_pure_eaf_flags, false, true);
/* If the call is to a replaceable operator delete and results
from a delete expression as opposed to a direct call to
such operator, then the effects for PTA (in particular
the escaping of the pointer) can be ignored. */
else if (fndecl
&& DECL_IS_OPERATOR_DELETE_P (fndecl)
&& gimple_call_from_new_or_delete (t))
;
else
handle_rhs_call (t, &rhsc, 0, true, true);
if (gimple_call_lhs (t))
handle_lhs_call (t, gimple_call_lhs (t),
gimple_call_return_flags (t), rhsc, fndecl);
}
else
{
auto_vec<ce_s, 2> rhsc;
tree lhsop;
unsigned j;
/* Assign all the passed arguments to the appropriate incoming
parameters of the function. */
for (j = 0; j < gimple_call_num_args (t); j++)
{
tree arg = gimple_call_arg (t, j);
find_func_aliases_for_call_arg (fi, j, arg);
}
/* If we are returning a value, assign it to the result. */
lhsop = gimple_call_lhs (t);
if (lhsop)
{
auto_vec<ce_s, 2> lhsc;
struct constraint_expr rhs;
struct constraint_expr *lhsp;
bool aggr_p = aggregate_value_p (lhsop, gimple_call_fntype (t));
get_constraint_for (lhsop, &lhsc);
rhs = get_function_part_constraint (fi, fi_result);
if (aggr_p)
{
auto_vec<ce_s, 2> tem;
tem.quick_push (rhs);
do_deref (&tem);
gcc_checking_assert (tem.length () == 1);
rhs = tem[0];
}
FOR_EACH_VEC_ELT (lhsc, j, lhsp)
process_constraint (new_constraint (*lhsp, rhs));
/* If we pass the result decl by reference, honor that. */
if (aggr_p)
{
struct constraint_expr lhs;
struct constraint_expr *rhsp;
get_constraint_for_address_of (lhsop, &rhsc);
lhs = get_function_part_constraint (fi, fi_result);
FOR_EACH_VEC_ELT (rhsc, j, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
rhsc.truncate (0);
}
}
/* If we use a static chain, pass it along. */
if (gimple_call_chain (t))
{
struct constraint_expr lhs;
struct constraint_expr *rhsp;
get_constraint_for (gimple_call_chain (t), &rhsc);
lhs = get_function_part_constraint (fi, fi_static_chain);
FOR_EACH_VEC_ELT (rhsc, j, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
}
}
}
/* Walk statement T setting up aliasing constraints according to the
references found in T. This function is the main part of the
constraint builder. AI points to auxiliary alias information used
when building alias sets and computing alias grouping heuristics. */
static void
find_func_aliases (struct function *fn, gimple *origt)
{
gimple *t = origt;
auto_vec<ce_s, 16> lhsc;
auto_vec<ce_s, 16> rhsc;
varinfo_t fi;
/* Now build constraints expressions. */
if (gimple_code (t) == GIMPLE_PHI)
{
/* For a phi node, assign all the arguments to
the result. */
get_constraint_for (gimple_phi_result (t), &lhsc);
for (unsigned i = 0; i < gimple_phi_num_args (t); i++)
{
get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
process_all_all_constraints (lhsc, rhsc);
rhsc.truncate (0);
}
}
/* In IPA mode, we need to generate constraints to pass call
arguments through their calls. There are two cases,
either a GIMPLE_CALL returning a value, or just a plain
GIMPLE_CALL when we are not.
In non-ipa mode, we need to generate constraints for each
pointer passed by address. */
else if (is_gimple_call (t))
find_func_aliases_for_call (fn, as_a <gcall *> (t));
/* Otherwise, just a regular assignment statement. Only care about
operations with pointer result, others are dealt with as escape
points if they have pointer operands. */
else if (is_gimple_assign (t))
{
/* Otherwise, just a regular assignment statement. */
tree lhsop = gimple_assign_lhs (t);
tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
if (rhsop && TREE_CLOBBER_P (rhsop))
/* Ignore clobbers, they don't actually store anything into
the LHS. */
;
else if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
do_structure_copy (lhsop, rhsop);
else
{
enum tree_code code = gimple_assign_rhs_code (t);
get_constraint_for (lhsop, &lhsc);
if (code == POINTER_PLUS_EXPR)
get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
gimple_assign_rhs2 (t), &rhsc);
else if (code == POINTER_DIFF_EXPR)
/* The result is not a pointer (part). */
;
else if (code == BIT_AND_EXPR
&& TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
{
/* Aligning a pointer via a BIT_AND_EXPR is offsetting
the pointer. Handle it by offsetting it by UNKNOWN. */
get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
NULL_TREE, &rhsc);
}
else if (code == TRUNC_DIV_EXPR
|| code == CEIL_DIV_EXPR
|| code == FLOOR_DIV_EXPR
|| code == ROUND_DIV_EXPR
|| code == EXACT_DIV_EXPR
|| code == TRUNC_MOD_EXPR
|| code == CEIL_MOD_EXPR
|| code == FLOOR_MOD_EXPR
|| code == ROUND_MOD_EXPR)
/* Division and modulo transfer the pointer from the LHS. */
get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
NULL_TREE, &rhsc);
else if (CONVERT_EXPR_CODE_P (code)
|| gimple_assign_single_p (t))
/* See through conversions, single RHS are handled by
get_constraint_for_rhs. */
get_constraint_for_rhs (rhsop, &rhsc);
else if (code == COND_EXPR)
{
/* The result is a merge of both COND_EXPR arms. */
auto_vec<ce_s, 2> tmp;
struct constraint_expr *rhsp;
unsigned i;
get_constraint_for_rhs (gimple_assign_rhs2 (t), &rhsc);
get_constraint_for_rhs (gimple_assign_rhs3 (t), &tmp);
FOR_EACH_VEC_ELT (tmp, i, rhsp)
rhsc.safe_push (*rhsp);
}
else if (truth_value_p (code))
/* Truth value results are not pointer (parts). Or at least
very unreasonable obfuscation of a part. */
;
else
{
/* All other operations are possibly offsetting merges. */
auto_vec<ce_s, 4> tmp;
struct constraint_expr *rhsp;
unsigned i, j;
get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
NULL_TREE, &rhsc);
for (i = 2; i < gimple_num_ops (t); ++i)
{
get_constraint_for_ptr_offset (gimple_op (t, i),
NULL_TREE, &tmp);
FOR_EACH_VEC_ELT (tmp, j, rhsp)
rhsc.safe_push (*rhsp);
tmp.truncate (0);
}
}
process_all_all_constraints (lhsc, rhsc);
}
/* If there is a store to a global variable the rhs escapes. */
if ((lhsop = get_base_address (lhsop)) != NULL_TREE
&& DECL_P (lhsop))
{
varinfo_t vi = get_vi_for_tree (lhsop);
if ((! in_ipa_mode && vi->is_global_var)
|| vi->is_ipa_escape_point)
make_escape_constraint (rhsop);
}
}
/* Handle escapes through return. */
else if (gimple_code (t) == GIMPLE_RETURN
&& gimple_return_retval (as_a <greturn *> (t)) != NULL_TREE)
{
greturn *return_stmt = as_a <greturn *> (t);
fi = NULL;
if (!in_ipa_mode
&& SSA_VAR_P (gimple_return_retval (return_stmt)))
{
/* We handle simple returns by post-processing the solutions. */
;
}
if (!(fi = get_vi_for_tree (fn->decl)))
make_escape_constraint (gimple_return_retval (return_stmt));
else if (in_ipa_mode)
{
struct constraint_expr lhs ;
struct constraint_expr *rhsp;
unsigned i;
lhs = get_function_part_constraint (fi, fi_result);
get_constraint_for_rhs (gimple_return_retval (return_stmt), &rhsc);
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
}
}
/* Handle asms conservatively by adding escape constraints to everything. */
else if (gasm *asm_stmt = dyn_cast <gasm *> (t))
{
unsigned i, noutputs;
const char **oconstraints;
const char *constraint;
bool allows_mem, allows_reg, is_inout;
noutputs = gimple_asm_noutputs (asm_stmt);
oconstraints = XALLOCAVEC (const char *, noutputs);
for (i = 0; i < noutputs; ++i)
{
tree link = gimple_asm_output_op (asm_stmt, i);
tree op = TREE_VALUE (link);
constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
oconstraints[i] = constraint;
parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
&allows_reg, &is_inout);
/* A memory constraint makes the address of the operand escape. */
if (!allows_reg && allows_mem)
make_escape_constraint (build_fold_addr_expr (op));
/* The asm may read global memory, so outputs may point to
any global memory. */
if (op)
{
auto_vec<ce_s, 2> lhsc;
struct constraint_expr rhsc, *lhsp;
unsigned j;
get_constraint_for (op, &lhsc);
rhsc.var = nonlocal_id;
rhsc.offset = 0;
rhsc.type = SCALAR;
FOR_EACH_VEC_ELT (lhsc, j, lhsp)
process_constraint (new_constraint (*lhsp, rhsc));
}
}
for (i = 0; i < gimple_asm_ninputs (asm_stmt); ++i)
{
tree link = gimple_asm_input_op (asm_stmt, i);
tree op = TREE_VALUE (link);
constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
&allows_mem, &allows_reg);
/* A memory constraint makes the address of the operand escape. */
if (!allows_reg && allows_mem)
make_escape_constraint (build_fold_addr_expr (op));
/* Strictly we'd only need the constraint to ESCAPED if
the asm clobbers memory, otherwise using something
along the lines of per-call clobbers/uses would be enough. */
else if (op)
make_escape_constraint (op);
}
}
}
/* Create a constraint adding to the clobber set of FI the memory
pointed to by PTR. */
static void
process_ipa_clobber (varinfo_t fi, tree ptr)
{
vec<ce_s> ptrc = vNULL;
struct constraint_expr *c, lhs;
unsigned i;
get_constraint_for_rhs (ptr, &ptrc);
lhs = get_function_part_constraint (fi, fi_clobbers);
FOR_EACH_VEC_ELT (ptrc, i, c)
process_constraint (new_constraint (lhs, *c));
ptrc.release ();
}
/* Walk statement T setting up clobber and use constraints according to the
references found in T. This function is a main part of the
IPA constraint builder. */
static void
find_func_clobbers (struct function *fn, gimple *origt)
{
gimple *t = origt;
auto_vec<ce_s, 16> lhsc;
auto_vec<ce_s, 16> rhsc;
varinfo_t fi;
/* Add constraints for clobbered/used in IPA mode.
We are not interested in what automatic variables are clobbered
or used as we only use the information in the caller to which
they do not escape. */
gcc_assert (in_ipa_mode);
/* If the stmt refers to memory in any way it better had a VUSE. */
if (gimple_vuse (t) == NULL_TREE)
return;
/* We'd better have function information for the current function. */
fi = lookup_vi_for_tree (fn->decl);
gcc_assert (fi != NULL);
/* Account for stores in assignments and calls. */
if (gimple_vdef (t) != NULL_TREE
&& gimple_has_lhs (t))
{
tree lhs = gimple_get_lhs (t);
tree tem = lhs;
while (handled_component_p (tem))
tem = TREE_OPERAND (tem, 0);
if ((DECL_P (tem)
&& !auto_var_in_fn_p (tem, fn->decl))
|| INDIRECT_REF_P (tem)
|| (TREE_CODE (tem) == MEM_REF
&& !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
&& auto_var_in_fn_p
(TREE_OPERAND (TREE_OPERAND (tem, 0), 0), fn->decl))))
{
struct constraint_expr lhsc, *rhsp;
unsigned i;
lhsc = get_function_part_constraint (fi, fi_clobbers);
get_constraint_for_address_of (lhs, &rhsc);
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (lhsc, *rhsp));
rhsc.truncate (0);
}
}
/* Account for uses in assigments and returns. */
if (gimple_assign_single_p (t)
|| (gimple_code (t) == GIMPLE_RETURN
&& gimple_return_retval (as_a <greturn *> (t)) != NULL_TREE))
{
tree rhs = (gimple_assign_single_p (t)
? gimple_assign_rhs1 (t)
: gimple_return_retval (as_a <greturn *> (t)));
tree tem = rhs;
while (handled_component_p (tem))
tem = TREE_OPERAND (tem, 0);
if ((DECL_P (tem)
&& !auto_var_in_fn_p (tem, fn->decl))
|| INDIRECT_REF_P (tem)
|| (TREE_CODE (tem) == MEM_REF
&& !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
&& auto_var_in_fn_p
(TREE_OPERAND (TREE_OPERAND (tem, 0), 0), fn->decl))))
{
struct constraint_expr lhs, *rhsp;
unsigned i;
lhs = get_function_part_constraint (fi, fi_uses);
get_constraint_for_address_of (rhs, &rhsc);
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
rhsc.truncate (0);
}
}
if (gcall *call_stmt = dyn_cast <gcall *> (t))
{
varinfo_t cfi = NULL;
tree decl = gimple_call_fndecl (t);
struct constraint_expr lhs, rhs;
unsigned i, j;
/* For builtins we do not have separate function info. For those
we do not generate escapes for we have to generate clobbers/uses. */
if (gimple_call_builtin_p (t, BUILT_IN_NORMAL))
switch (DECL_FUNCTION_CODE (decl))
{
/* The following functions use and clobber memory pointed to
by their arguments. */
case BUILT_IN_STRCPY:
case BUILT_IN_STRNCPY:
case BUILT_IN_BCOPY:
case BUILT_IN_MEMCPY:
case BUILT_IN_MEMMOVE:
case BUILT_IN_MEMPCPY:
case BUILT_IN_STPCPY:
case BUILT_IN_STPNCPY:
case BUILT_IN_STRCAT:
case BUILT_IN_STRNCAT:
case BUILT_IN_STRCPY_CHK:
case BUILT_IN_STRNCPY_CHK:
case BUILT_IN_MEMCPY_CHK:
case BUILT_IN_MEMMOVE_CHK:
case BUILT_IN_MEMPCPY_CHK:
case BUILT_IN_STPCPY_CHK:
case BUILT_IN_STPNCPY_CHK:
case BUILT_IN_STRCAT_CHK:
case BUILT_IN_STRNCAT_CHK:
{
tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
== BUILT_IN_BCOPY ? 1 : 0));
tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
== BUILT_IN_BCOPY ? 0 : 1));
unsigned i;
struct constraint_expr *rhsp, *lhsp;
get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
lhs = get_function_part_constraint (fi, fi_clobbers);
FOR_EACH_VEC_ELT (lhsc, i, lhsp)
process_constraint (new_constraint (lhs, *lhsp));
get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
lhs = get_function_part_constraint (fi, fi_uses);
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
return;
}
/* The following function clobbers memory pointed to by
its argument. */
case BUILT_IN_MEMSET:
case BUILT_IN_MEMSET_CHK:
case BUILT_IN_POSIX_MEMALIGN:
{
tree dest = gimple_call_arg (t, 0);
unsigned i;
ce_s *lhsp;
get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
lhs = get_function_part_constraint (fi, fi_clobbers);
FOR_EACH_VEC_ELT (lhsc, i, lhsp)
process_constraint (new_constraint (lhs, *lhsp));
return;
}
/* The following functions clobber their second and third
arguments. */
case BUILT_IN_SINCOS:
case BUILT_IN_SINCOSF:
case BUILT_IN_SINCOSL:
{
process_ipa_clobber (fi, gimple_call_arg (t, 1));
process_ipa_clobber (fi, gimple_call_arg (t, 2));
return;
}
/* The following functions clobber their second argument. */
case BUILT_IN_FREXP:
case BUILT_IN_FREXPF:
case BUILT_IN_FREXPL:
case BUILT_IN_LGAMMA_R:
case BUILT_IN_LGAMMAF_R:
case BUILT_IN_LGAMMAL_R:
case BUILT_IN_GAMMA_R:
case BUILT_IN_GAMMAF_R:
case BUILT_IN_GAMMAL_R:
case BUILT_IN_MODF:
case BUILT_IN_MODFF:
case BUILT_IN_MODFL:
{
process_ipa_clobber (fi, gimple_call_arg (t, 1));
return;
}
/* The following functions clobber their third argument. */
case BUILT_IN_REMQUO:
case BUILT_IN_REMQUOF:
case BUILT_IN_REMQUOL:
{
process_ipa_clobber (fi, gimple_call_arg (t, 2));
return;
}
/* The following functions neither read nor clobber memory. */
case BUILT_IN_ASSUME_ALIGNED:
case BUILT_IN_FREE:
return;
/* Trampolines are of no interest to us. */
case BUILT_IN_INIT_TRAMPOLINE:
case BUILT_IN_ADJUST_TRAMPOLINE:
return;
case BUILT_IN_VA_START:
case BUILT_IN_VA_END:
return;
case BUILT_IN_GOMP_PARALLEL:
case BUILT_IN_GOACC_PARALLEL:
{
unsigned int fnpos, argpos;
unsigned int implicit_use_args[2];
unsigned int num_implicit_use_args = 0;
switch (DECL_FUNCTION_CODE (decl))
{
case BUILT_IN_GOMP_PARALLEL:
/* __builtin_GOMP_parallel (fn, data, num_threads, flags). */
fnpos = 0;
argpos = 1;
break;
case BUILT_IN_GOACC_PARALLEL:
/* __builtin_GOACC_parallel (flags_m, fn, mapnum, hostaddrs,
sizes, kinds, ...). */
fnpos = 1;
argpos = 3;
implicit_use_args[num_implicit_use_args++] = 4;
implicit_use_args[num_implicit_use_args++] = 5;
break;
default:
gcc_unreachable ();
}
tree fnarg = gimple_call_arg (t, fnpos);
gcc_assert (TREE_CODE (fnarg) == ADDR_EXPR);
tree fndecl = TREE_OPERAND (fnarg, 0);
if (fndecl_maybe_in_other_partition (fndecl))
/* Fallthru to general call handling. */
break;
varinfo_t cfi = get_vi_for_tree (fndecl);
tree arg = gimple_call_arg (t, argpos);
/* Parameter passed by value is used. */
lhs = get_function_part_constraint (fi, fi_uses);
struct constraint_expr *rhsp;
get_constraint_for (arg, &rhsc);
FOR_EACH_VEC_ELT (rhsc, j, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
rhsc.truncate (0);
/* Handle parameters used by the call, but not used in cfi, as
implicitly used by cfi. */
lhs = get_function_part_constraint (cfi, fi_uses);
for (unsigned i = 0; i < num_implicit_use_args; ++i)
{
tree arg = gimple_call_arg (t, implicit_use_args[i]);
get_constraint_for (arg, &rhsc);
FOR_EACH_VEC_ELT (rhsc, j, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
rhsc.truncate (0);
}
/* The caller clobbers what the callee does. */
lhs = get_function_part_constraint (fi, fi_clobbers);
rhs = get_function_part_constraint (cfi, fi_clobbers);
process_constraint (new_constraint (lhs, rhs));
/* The caller uses what the callee does. */
lhs = get_function_part_constraint (fi, fi_uses);
rhs = get_function_part_constraint (cfi, fi_uses);
process_constraint (new_constraint (lhs, rhs));
return;
}
/* printf-style functions may have hooks to set pointers to
point to somewhere into the generated string. Leave them
for a later exercise... */
default:
/* Fallthru to general call handling. */;
}
/* Parameters passed by value are used. */
lhs = get_function_part_constraint (fi, fi_uses);
for (i = 0; i < gimple_call_num_args (t); i++)
{
struct constraint_expr *rhsp;
tree arg = gimple_call_arg (t, i);
if (TREE_CODE (arg) == SSA_NAME
|| is_gimple_min_invariant (arg))
continue;
get_constraint_for_address_of (arg, &rhsc);
FOR_EACH_VEC_ELT (rhsc, j, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
rhsc.truncate (0);
}
/* Build constraints for propagating clobbers/uses along the
callgraph edges. */
cfi = get_fi_for_callee (call_stmt);
if (cfi->id == anything_id)
{
if (gimple_vdef (t))
make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
anything_id);
make_constraint_from (first_vi_for_offset (fi, fi_uses),
anything_id);
return;
}
/* For callees without function info (that's external functions),
ESCAPED is clobbered and used. */
if (cfi->decl
&& TREE_CODE (cfi->decl) == FUNCTION_DECL
&& !cfi->is_fn_info)
{
varinfo_t vi;
if (gimple_vdef (t))
make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
escaped_id);
make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
/* Also honor the call statement use/clobber info. */
if ((vi = lookup_call_clobber_vi (call_stmt)) != NULL)
make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
vi->id);
if ((vi = lookup_call_use_vi (call_stmt)) != NULL)
make_copy_constraint (first_vi_for_offset (fi, fi_uses),
vi->id);
return;
}
/* Otherwise the caller clobbers and uses what the callee does.
??? This should use a new complex constraint that filters
local variables of the callee. */
if (gimple_vdef (t))
{
lhs = get_function_part_constraint (fi, fi_clobbers);
rhs = get_function_part_constraint (cfi, fi_clobbers);
process_constraint (new_constraint (lhs, rhs));
}
lhs = get_function_part_constraint (fi, fi_uses);
rhs = get_function_part_constraint (cfi, fi_uses);
process_constraint (new_constraint (lhs, rhs));
}
else if (gimple_code (t) == GIMPLE_ASM)
{
/* ??? Ick. We can do better. */
if (gimple_vdef (t))
make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
anything_id);
make_constraint_from (first_vi_for_offset (fi, fi_uses),
anything_id);
}
}
/* Find the first varinfo in the same variable as START that overlaps with
OFFSET. Return NULL if we can't find one. */
static varinfo_t
first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
{
/* If the offset is outside of the variable, bail out. */
if (offset >= start->fullsize)
return NULL;
/* If we cannot reach offset from start, lookup the first field
and start from there. */
if (start->offset > offset)
start = get_varinfo (start->head);
while (start)
{
/* We may not find a variable in the field list with the actual
offset when we have glommed a structure to a variable.
In that case, however, offset should still be within the size
of the variable. */
if (offset >= start->offset
&& (offset - start->offset) < start->size)
return start;
start = vi_next (start);
}
return NULL;
}
/* Find the first varinfo in the same variable as START that overlaps with
OFFSET. If there is no such varinfo the varinfo directly preceding
OFFSET is returned. */
static varinfo_t
first_or_preceding_vi_for_offset (varinfo_t start,
unsigned HOST_WIDE_INT offset)
{
/* If we cannot reach offset from start, lookup the first field
and start from there. */
if (start->offset > offset)
start = get_varinfo (start->head);
/* We may not find a variable in the field list with the actual
offset when we have glommed a structure to a variable.
In that case, however, offset should still be within the size
of the variable.
If we got beyond the offset we look for return the field
directly preceding offset which may be the last field. */
while (start->next
&& offset >= start->offset
&& !((offset - start->offset) < start->size))
start = vi_next (start);
return start;
}
/* This structure is used during pushing fields onto the fieldstack
to track the offset of the field, since bitpos_of_field gives it
relative to its immediate containing type, and we want it relative
to the ultimate containing object. */
struct fieldoff
{
/* Offset from the base of the base containing object to this field. */
HOST_WIDE_INT offset;
/* Size, in bits, of the field. */
unsigned HOST_WIDE_INT size;
unsigned has_unknown_size : 1;
unsigned must_have_pointers : 1;
unsigned may_have_pointers : 1;
unsigned only_restrict_pointers : 1;
tree restrict_pointed_type;
};
typedef struct fieldoff fieldoff_s;
/* qsort comparison function for two fieldoff's PA and PB */
static int
fieldoff_compare (const void *pa, const void *pb)
{
const fieldoff_s *foa = (const fieldoff_s *)pa;
const fieldoff_s *fob = (const fieldoff_s *)pb;
unsigned HOST_WIDE_INT foasize, fobsize;
if (foa->offset < fob->offset)
return -1;
else if (foa->offset > fob->offset)
return 1;
foasize = foa->size;
fobsize = fob->size;
if (foasize < fobsize)
return -1;
else if (foasize > fobsize)
return 1;
return 0;
}
/* Sort a fieldstack according to the field offset and sizes. */
static void
sort_fieldstack (vec<fieldoff_s> &fieldstack)
{
fieldstack.qsort (fieldoff_compare);
}
/* Return true if T is a type that can have subvars. */
static inline bool
type_can_have_subvars (const_tree t)
{
/* Aggregates without overlapping fields can have subvars. */
return TREE_CODE (t) == RECORD_TYPE;
}
/* Return true if V is a tree that we can have subvars for.
Normally, this is any aggregate type. Also complex
types which are not gimple registers can have subvars. */
static inline bool
var_can_have_subvars (const_tree v)
{
/* Volatile variables should never have subvars. */
if (TREE_THIS_VOLATILE (v))
return false;
/* Non decls or memory tags can never have subvars. */
if (!DECL_P (v))
return false;
return type_can_have_subvars (TREE_TYPE (v));
}
/* Return true if T is a type that does contain pointers. */
static bool
type_must_have_pointers (tree type)
{
if (POINTER_TYPE_P (type))
return true;
if (TREE_CODE (type) == ARRAY_TYPE)
return type_must_have_pointers (TREE_TYPE (type));
/* A function or method can have pointers as arguments, so track
those separately. */
if (TREE_CODE (type) == FUNCTION_TYPE
|| TREE_CODE (type) == METHOD_TYPE)
return true;
return false;
}
static bool
field_must_have_pointers (tree t)
{
return type_must_have_pointers (TREE_TYPE (t));
}
/* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
the fields of TYPE onto fieldstack, recording their offsets along
the way.
OFFSET is used to keep track of the offset in this entire
structure, rather than just the immediately containing structure.
Returns false if the caller is supposed to handle the field we
recursed for. */
static bool
push_fields_onto_fieldstack (tree type, vec<fieldoff_s> *fieldstack,
HOST_WIDE_INT offset)
{
tree field;
bool empty_p = true;
if (TREE_CODE (type) != RECORD_TYPE)
return false;
/* If the vector of fields is growing too big, bail out early.
Callers check for vec::length <= param_max_fields_for_field_sensitive, make
sure this fails. */
if (fieldstack->length () > (unsigned)param_max_fields_for_field_sensitive)
return false;
for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
if (TREE_CODE (field) == FIELD_DECL)
{
bool push = false;
HOST_WIDE_INT foff = bitpos_of_field (field);
tree field_type = TREE_TYPE (field);
if (!var_can_have_subvars (field)
|| TREE_CODE (field_type) == QUAL_UNION_TYPE
|| TREE_CODE (field_type) == UNION_TYPE)
push = true;
else if (!push_fields_onto_fieldstack
(field_type, fieldstack, offset + foff)
&& (DECL_SIZE (field)
&& !integer_zerop (DECL_SIZE (field))))
/* Empty structures may have actual size, like in C++. So
see if we didn't push any subfields and the size is
nonzero, push the field onto the stack. */
push = true;
if (push)
{
fieldoff_s *pair = NULL;
bool has_unknown_size = false;
bool must_have_pointers_p;
if (!fieldstack->is_empty ())
pair = &fieldstack->last ();
/* If there isn't anything at offset zero, create sth. */
if (!pair
&& offset + foff != 0)
{
fieldoff_s e
= {0, offset + foff, false, false, true, false, NULL_TREE};
pair = fieldstack->safe_push (e);
}
if (!DECL_SIZE (field)
|| !tree_fits_uhwi_p (DECL_SIZE (field)))
has_unknown_size = true;
/* If adjacent fields do not contain pointers merge them. */
must_have_pointers_p = field_must_have_pointers (field);
if (pair
&& !has_unknown_size
&& !must_have_pointers_p
&& !pair->must_have_pointers
&& !pair->has_unknown_size
&& pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
{
pair->size += tree_to_uhwi (DECL_SIZE (field));
}
else
{
fieldoff_s e;
e.offset = offset + foff;
e.has_unknown_size = has_unknown_size;
if (!has_unknown_size)
e.size = tree_to_uhwi (DECL_SIZE (field));
else
e.size = -1;
e.must_have_pointers = must_have_pointers_p;
e.may_have_pointers = true;
e.only_restrict_pointers
= (!has_unknown_size
&& POINTER_TYPE_P (field_type)
&& TYPE_RESTRICT (field_type));
if (e.only_restrict_pointers)
e.restrict_pointed_type = TREE_TYPE (field_type);
fieldstack->safe_push (e);
}
}
empty_p = false;
}
return !empty_p;
}
/* Count the number of arguments DECL has, and set IS_VARARGS to true
if it is a varargs function. */
static unsigned int
count_num_arguments (tree decl, bool *is_varargs)
{
unsigned int num = 0;
tree t;
/* Capture named arguments for K&R functions. They do not
have a prototype and thus no TYPE_ARG_TYPES. */
for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
++num;
/* Check if the function has variadic arguments. */
for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
if (TREE_VALUE (t) == void_type_node)
break;
if (!t)
*is_varargs = true;
return num;
}
/* Creation function node for DECL, using NAME, and return the index
of the variable we've created for the function. If NONLOCAL_p, create
initial constraints. */
static varinfo_t
create_function_info_for (tree decl, const char *name, bool add_id,
bool nonlocal_p)
{
struct function *fn = DECL_STRUCT_FUNCTION (decl);
varinfo_t vi, prev_vi;
tree arg;
unsigned int i;
bool is_varargs = false;
unsigned int num_args = count_num_arguments (decl, &is_varargs);
/* Create the variable info. */
vi = new_var_info (decl, name, add_id);
vi->offset = 0;
vi->size = 1;
vi->fullsize = fi_parm_base + num_args;
vi->is_fn_info = 1;
vi->may_have_pointers = false;
if (is_varargs)
vi->fullsize = ~0;
insert_vi_for_tree (vi->decl, vi);
prev_vi = vi;
/* Create a variable for things the function clobbers and one for
things the function uses. */
{
varinfo_t clobbervi, usevi;
const char *newname;
char *tempname;
tempname = xasprintf ("%s.clobber", name);
newname = ggc_strdup (tempname);
free (tempname);
clobbervi = new_var_info (NULL, newname, false);
clobbervi->offset = fi_clobbers;
clobbervi->size = 1;
clobbervi->fullsize = vi->fullsize;
clobbervi->is_full_var = true;
clobbervi->is_global_var = false;
clobbervi->is_reg_var = true;
gcc_assert (prev_vi->offset < clobbervi->offset);
prev_vi->next = clobbervi->id;
prev_vi = clobbervi;
tempname = xasprintf ("%s.use", name);
newname = ggc_strdup (tempname);
free (tempname);
usevi = new_var_info (NULL, newname, false);
usevi->offset = fi_uses;
usevi->size = 1;
usevi->fullsize = vi->fullsize;
usevi->is_full_var = true;
usevi->is_global_var = false;
usevi->is_reg_var = true;
gcc_assert (prev_vi->offset < usevi->offset);
prev_vi->next = usevi->id;
prev_vi = usevi;
}
/* And one for the static chain. */
if (fn->static_chain_decl != NULL_TREE)
{
varinfo_t chainvi;
const char *newname;
char *tempname;
tempname = xasprintf ("%s.chain", name);
newname = ggc_strdup (tempname);
free (tempname);
chainvi = new_var_info (fn->static_chain_decl, newname, false);
chainvi->offset = fi_static_chain;
chainvi->size = 1;
chainvi->fullsize = vi->fullsize;
chainvi->is_full_var = true;
chainvi->is_global_var = false;
insert_vi_for_tree (fn->static_chain_decl, chainvi);
if (nonlocal_p
&& chainvi->may_have_pointers)
make_constraint_from (chainvi, nonlocal_id);
gcc_assert (prev_vi->offset < chainvi->offset);
prev_vi->next = chainvi->id;
prev_vi = chainvi;
}
/* Create a variable for the return var. */
if (DECL_RESULT (decl) != NULL
|| !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
{
varinfo_t resultvi;
const char *newname;
char *tempname;
tree resultdecl = decl;
if (DECL_RESULT (decl))
resultdecl = DECL_RESULT (decl);
tempname = xasprintf ("%s.result", name);
newname = ggc_strdup (tempname);
free (tempname);
resultvi = new_var_info (resultdecl, newname, false);
resultvi->offset = fi_result;
resultvi->size = 1;
resultvi->fullsize = vi->fullsize;
resultvi->is_full_var = true;
if (DECL_RESULT (decl))
resultvi->may_have_pointers = true;
if (DECL_RESULT (decl))
insert_vi_for_tree (DECL_RESULT (decl), resultvi);
if (nonlocal_p
&& DECL_RESULT (decl)
&& DECL_BY_REFERENCE (DECL_RESULT (decl)))
make_constraint_from (resultvi, nonlocal_id);
gcc_assert (prev_vi->offset < resultvi->offset);
prev_vi->next = resultvi->id;
prev_vi = resultvi;
}
/* We also need to make function return values escape. Nothing
escapes by returning from main though. */
if (nonlocal_p
&& !MAIN_NAME_P (DECL_NAME (decl)))
{
varinfo_t fi, rvi;
fi = lookup_vi_for_tree (decl);
rvi = first_vi_for_offset (fi, fi_result);
if (rvi && rvi->offset == fi_result)
make_copy_constraint (get_varinfo (escaped_id), rvi->id);
}
/* Set up variables for each argument. */
arg = DECL_ARGUMENTS (decl);
for (i = 0; i < num_args; i++)
{
varinfo_t argvi;
const char *newname;
char *tempname;
tree argdecl = decl;
if (arg)
argdecl = arg;
tempname = xasprintf ("%s.arg%d", name, i);
newname = ggc_strdup (tempname);
free (tempname);
argvi = new_var_info (argdecl, newname, false);
argvi->offset = fi_parm_base + i;
argvi->size = 1;
argvi->is_full_var = true;
argvi->fullsize = vi->fullsize;
if (arg)
argvi->may_have_pointers = true;
if (arg)
insert_vi_for_tree (arg, argvi);
if (nonlocal_p
&& argvi->may_have_pointers)
make_constraint_from (argvi, nonlocal_id);
gcc_assert (prev_vi->offset < argvi->offset);
prev_vi->next = argvi->id;
prev_vi = argvi;
if (arg)
arg = DECL_CHAIN (arg);
}
/* Add one representative for all further args. */
if (is_varargs)
{
varinfo_t argvi;
const char *newname;
char *tempname;
tree decl;
tempname = xasprintf ("%s.varargs", name);
newname = ggc_strdup (tempname);
free (tempname);
/* We need sth that can be pointed to for va_start. */
decl = build_fake_var_decl (ptr_type_node);
argvi = new_var_info (decl, newname, false);
argvi->offset = fi_parm_base + num_args;
argvi->size = ~0;
argvi->is_full_var = true;
argvi->is_heap_var = true;
argvi->fullsize = vi->fullsize;
if (nonlocal_p
&& argvi->may_have_pointers)
make_constraint_from (argvi, nonlocal_id);
gcc_assert (prev_vi->offset < argvi->offset);
prev_vi->next = argvi->id;
}
return vi;
}
/* Return true if FIELDSTACK contains fields that overlap.
FIELDSTACK is assumed to be sorted by offset. */
static bool
check_for_overlaps (const vec<fieldoff_s> &fieldstack)
{
fieldoff_s *fo = NULL;
unsigned int i;
HOST_WIDE_INT lastoffset = -1;
FOR_EACH_VEC_ELT (fieldstack, i, fo)
{
if (fo->offset == lastoffset)
return true;
lastoffset = fo->offset;
}
return false;
}
/* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
This will also create any varinfo structures necessary for fields
of DECL. DECL is a function parameter if HANDLE_PARAM is set.
HANDLED_STRUCT_TYPE is used to register struct types reached by following
restrict pointers. This is needed to prevent infinite recursion.
If ADD_RESTRICT, pretend that the pointer NAME is restrict even if DECL
does not advertise it. */
static varinfo_t
create_variable_info_for_1 (tree decl, const char *name, bool add_id,
bool handle_param, bitmap handled_struct_type,
bool add_restrict = false)
{
varinfo_t vi, newvi;
tree decl_type = TREE_TYPE (decl);
tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
auto_vec<fieldoff_s> fieldstack;
fieldoff_s *fo;
unsigned int i;
if (!declsize
|| !tree_fits_uhwi_p (declsize))
{
vi = new_var_info (decl, name, add_id);
vi->offset = 0;
vi->size = ~0;
vi->fullsize = ~0;
vi->is_unknown_size_var = true;
vi->is_full_var = true;
vi->may_have_pointers = true;
return vi;
}
/* Collect field information. */
if (use_field_sensitive
&& var_can_have_subvars (decl)
/* ??? Force us to not use subfields for globals in IPA mode.
Else we'd have to parse arbitrary initializers. */
&& !(in_ipa_mode
&& is_global_var (decl)))
{
fieldoff_s *fo = NULL;
bool notokay = false;
unsigned int i;
push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
for (i = 0; !notokay && fieldstack.iterate (i, &fo); i++)
if (fo->has_unknown_size
|| fo->offset < 0)
{
notokay = true;
break;
}
/* We can't sort them if we have a field with a variable sized type,
which will make notokay = true. In that case, we are going to return
without creating varinfos for the fields anyway, so sorting them is a
waste to boot. */
if (!notokay)
{
sort_fieldstack (fieldstack);
/* Due to some C++ FE issues, like PR 22488, we might end up
what appear to be overlapping fields even though they,
in reality, do not overlap. Until the C++ FE is fixed,
we will simply disable field-sensitivity for these cases. */
notokay = check_for_overlaps (fieldstack);
}
if (notokay)
fieldstack.release ();
}
/* If we didn't end up collecting sub-variables create a full
variable for the decl. */
if (fieldstack.length () == 0
|| fieldstack.length () > (unsigned)param_max_fields_for_field_sensitive)
{
vi = new_var_info (decl, name, add_id);
vi->offset = 0;
vi->may_have_pointers = true;
vi->fullsize = tree_to_uhwi (declsize);
vi->size = vi->fullsize;
vi->is_full_var = true;
if (POINTER_TYPE_P (decl_type)
&& (TYPE_RESTRICT (decl_type) || add_restrict))
vi->only_restrict_pointers = 1;
if (vi->only_restrict_pointers
&& !type_contains_placeholder_p (TREE_TYPE (decl_type))
&& handle_param
&& !bitmap_bit_p (handled_struct_type,
TYPE_UID (TREE_TYPE (decl_type))))
{
varinfo_t rvi;
tree heapvar = build_fake_var_decl (TREE_TYPE (decl_type));
DECL_EXTERNAL (heapvar) = 1;
if (var_can_have_subvars (heapvar))
bitmap_set_bit (handled_struct_type,
TYPE_UID (TREE_TYPE (decl_type)));
rvi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS", true,
true, handled_struct_type);
if (var_can_have_subvars (heapvar))
bitmap_clear_bit (handled_struct_type,
TYPE_UID (TREE_TYPE (decl_type)));
rvi->is_restrict_var = 1;
insert_vi_for_tree (heapvar, rvi);
make_constraint_from (vi, rvi->id);
make_param_constraints (rvi);
}
fieldstack.release ();
return vi;
}
vi = new_var_info (decl, name, add_id);
vi->fullsize = tree_to_uhwi (declsize);
if (fieldstack.length () == 1)
vi->is_full_var = true;
for (i = 0, newvi = vi;
fieldstack.iterate (i, &fo);
++i, newvi = vi_next (newvi))
{
const char *newname = NULL;
char *tempname;
if (dump_file)
{
if (fieldstack.length () != 1)
{
tempname
= xasprintf ("%s." HOST_WIDE_INT_PRINT_DEC
"+" HOST_WIDE_INT_PRINT_DEC, name,
fo->offset, fo->size);
newname = ggc_strdup (tempname);
free (tempname);
}
}
else
newname = "NULL";
if (newname)
newvi->name = newname;
newvi->offset = fo->offset;
newvi->size = fo->size;
newvi->fullsize = vi->fullsize;
newvi->may_have_pointers = fo->may_have_pointers;
newvi->only_restrict_pointers = fo->only_restrict_pointers;
if (handle_param
&& newvi->only_restrict_pointers
&& !type_contains_placeholder_p (fo->restrict_pointed_type)
&& !bitmap_bit_p (handled_struct_type,
TYPE_UID (fo->restrict_pointed_type)))
{
varinfo_t rvi;
tree heapvar = build_fake_var_decl (fo->restrict_pointed_type);
DECL_EXTERNAL (heapvar) = 1;
if (var_can_have_subvars (heapvar))
bitmap_set_bit (handled_struct_type,
TYPE_UID (fo->restrict_pointed_type));
rvi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS", true,
true, handled_struct_type);
if (var_can_have_subvars (heapvar))
bitmap_clear_bit (handled_struct_type,
TYPE_UID (fo->restrict_pointed_type));
rvi->is_restrict_var = 1;
insert_vi_for_tree (heapvar, rvi);
make_constraint_from (newvi, rvi->id);
make_param_constraints (rvi);
}
if (i + 1 < fieldstack.length ())
{
varinfo_t tem = new_var_info (decl, name, false);
newvi->next = tem->id;
tem->head = vi->id;
}
}
return vi;
}
static unsigned int
create_variable_info_for (tree decl, const char *name, bool add_id)
{
/* First see if we are dealing with an ifunc resolver call and
assiociate that with a call to the resolver function result. */
cgraph_node *node;
if (in_ipa_mode
&& TREE_CODE (decl) == FUNCTION_DECL
&& (node = cgraph_node::get (decl))
&& node->ifunc_resolver)
{
varinfo_t fi = get_vi_for_tree (node->get_alias_target ()->decl);
constraint_expr rhs
= get_function_part_constraint (fi, fi_result);
fi = new_var_info (NULL_TREE, "ifuncres", true);
fi->is_reg_var = true;
constraint_expr lhs;
lhs.type = SCALAR;
lhs.var = fi->id;
lhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
insert_vi_for_tree (decl, fi);
return fi->id;
}
varinfo_t vi = create_variable_info_for_1 (decl, name, add_id, false, NULL);
unsigned int id = vi->id;
insert_vi_for_tree (decl, vi);
if (!VAR_P (decl))
return id;
/* Create initial constraints for globals. */
for (; vi; vi = vi_next (vi))
{
if (!vi->may_have_pointers
|| !vi->is_global_var)
continue;
/* Mark global restrict qualified pointers. */
if ((POINTER_TYPE_P (TREE_TYPE (decl))
&& TYPE_RESTRICT (TREE_TYPE (decl)))
|| vi->only_restrict_pointers)
{
varinfo_t rvi
= make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT",
true);
/* ??? For now exclude reads from globals as restrict sources
if those are not (indirectly) from incoming parameters. */
rvi->is_restrict_var = false;
continue;
}
/* In non-IPA mode the initializer from nonlocal is all we need. */
if (!in_ipa_mode
|| DECL_HARD_REGISTER (decl))
make_copy_constraint (vi, nonlocal_id);
/* In IPA mode parse the initializer and generate proper constraints
for it. */
else
{
varpool_node *vnode = varpool_node::get (decl);
/* For escaped variables initialize them from nonlocal. */
if (!vnode->all_refs_explicit_p ())
make_copy_constraint (vi, nonlocal_id);
/* If this is a global variable with an initializer and we are in
IPA mode generate constraints for it. */
ipa_ref *ref;
for (unsigned idx = 0; vnode->iterate_reference (idx, ref); ++idx)
{
auto_vec<ce_s> rhsc;
struct constraint_expr lhs, *rhsp;
unsigned i;
get_constraint_for_address_of (ref->referred->decl, &rhsc);
lhs.var = vi->id;
lhs.offset = 0;
lhs.type = SCALAR;
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
/* If this is a variable that escapes from the unit
the initializer escapes as well. */
if (!vnode->all_refs_explicit_p ())
{
lhs.var = escaped_id;
lhs.offset = 0;
lhs.type = SCALAR;
FOR_EACH_VEC_ELT (rhsc, i, rhsp)
process_constraint (new_constraint (lhs, *rhsp));
}
}
}
}
return id;
}
/* Print out the points-to solution for VAR to FILE. */
static void
dump_solution_for_var (FILE *file, unsigned int var)
{
varinfo_t vi = get_varinfo (var);
unsigned int i;
bitmap_iterator bi;
/* Dump the solution for unified vars anyway, this avoids difficulties
in scanning dumps in the testsuite. */
fprintf (file, "%s = { ", vi->name);
vi = get_varinfo (find (var));
EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
fprintf (file, "%s ", get_varinfo (i)->name);
fprintf (file, "}");
/* But note when the variable was unified. */
if (vi->id != var)
fprintf (file, " same as %s", vi->name);
fprintf (file, "\n");
}
/* Print the points-to solution for VAR to stderr. */
DEBUG_FUNCTION void
debug_solution_for_var (unsigned int var)
{
dump_solution_for_var (stderr, var);
}
/* Register the constraints for function parameter related VI. */
static void
make_param_constraints (varinfo_t vi)
{
for (; vi; vi = vi_next (vi))
{
if (vi->only_restrict_pointers)
;
else if (vi->may_have_pointers)
make_constraint_from (vi, nonlocal_id);
if (vi->is_full_var)
break;
}
}
/* Create varinfo structures for all of the variables in the
function for intraprocedural mode. */
static void
intra_create_variable_infos (struct function *fn)
{
tree t;
bitmap handled_struct_type = NULL;
bool this_parm_in_ctor = DECL_CXX_CONSTRUCTOR_P (fn->decl);
/* For each incoming pointer argument arg, create the constraint ARG
= NONLOCAL or a dummy variable if it is a restrict qualified
passed-by-reference argument. */
for (t = DECL_ARGUMENTS (fn->decl); t; t = DECL_CHAIN (t))
{
if (handled_struct_type == NULL)
handled_struct_type = BITMAP_ALLOC (NULL);
varinfo_t p
= create_variable_info_for_1 (t, alias_get_name (t), false, true,
handled_struct_type, this_parm_in_ctor);
insert_vi_for_tree (t, p);
make_param_constraints (p);
this_parm_in_ctor = false;
}
if (handled_struct_type != NULL)
BITMAP_FREE (handled_struct_type);
/* Add a constraint for a result decl that is passed by reference. */
if (DECL_RESULT (fn->decl)
&& DECL_BY_REFERENCE (DECL_RESULT (fn->decl)))
{
varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (fn->decl));
for (p = result_vi; p; p = vi_next (p))
make_constraint_from (p, nonlocal_id);
}
/* Add a constraint for the incoming static chain parameter. */
if (fn->static_chain_decl != NULL_TREE)
{
varinfo_t p, chain_vi = get_vi_for_tree (fn->static_chain_decl);
for (p = chain_vi; p; p = vi_next (p))
make_constraint_from (p, nonlocal_id);
}
}
/* Structure used to put solution bitmaps in a hashtable so they can
be shared among variables with the same points-to set. */
typedef struct shared_bitmap_info
{
bitmap pt_vars;
hashval_t hashcode;
} *shared_bitmap_info_t;
typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
/* Shared_bitmap hashtable helpers. */
struct shared_bitmap_hasher : free_ptr_hash <shared_bitmap_info>
{
static inline hashval_t hash (const shared_bitmap_info *);
static inline bool equal (const shared_bitmap_info *,
const shared_bitmap_info *);
};
/* Hash function for a shared_bitmap_info_t */
inline hashval_t
shared_bitmap_hasher::hash (const shared_bitmap_info *bi)
{
return bi->hashcode;
}
/* Equality function for two shared_bitmap_info_t's. */
inline bool
shared_bitmap_hasher::equal (const shared_bitmap_info *sbi1,
const shared_bitmap_info *sbi2)
{
return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
}
/* Shared_bitmap hashtable. */
static hash_table<shared_bitmap_hasher> *shared_bitmap_table;
/* Lookup a bitmap in the shared bitmap hashtable, and return an already
existing instance if there is one, NULL otherwise. */
static bitmap
shared_bitmap_lookup (bitmap pt_vars)
{
shared_bitmap_info **slot;
struct shared_bitmap_info sbi;
sbi.pt_vars = pt_vars;
sbi.hashcode = bitmap_hash (pt_vars);
slot = shared_bitmap_table->find_slot (&sbi, NO_INSERT);
if (!slot)
return NULL;
else
return (*slot)->pt_vars;
}
/* Add a bitmap to the shared bitmap hashtable. */
static void
shared_bitmap_add (bitmap pt_vars)
{
shared_bitmap_info **slot;
shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
sbi->pt_vars = pt_vars;
sbi->hashcode = bitmap_hash (pt_vars);
slot = shared_bitmap_table->find_slot (sbi, INSERT);
gcc_assert (!*slot);
*slot = sbi;
}
/* Set bits in INTO corresponding to the variable uids in solution set FROM. */
static void
set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt,
tree fndecl)
{
unsigned int i;
bitmap_iterator bi;
varinfo_t escaped_vi = get_varinfo (find (escaped_id));
bool everything_escaped
= escaped_vi->solution && bitmap_bit_p (escaped_vi->solution, anything_id);
EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
{
varinfo_t vi = get_varinfo (i);
if (vi->is_artificial_var)
continue;
if (everything_escaped
|| (escaped_vi->solution
&& bitmap_bit_p (escaped_vi->solution, i)))
{
pt->vars_contains_escaped = true;
pt->vars_contains_escaped_heap |= vi->is_heap_var;
}
if (vi->is_restrict_var)
pt->vars_contains_restrict = true;
if (VAR_P (vi->decl)
|| TREE_CODE (vi->decl) == PARM_DECL
|| TREE_CODE (vi->decl) == RESULT_DECL)
{
/* If we are in IPA mode we will not recompute points-to
sets after inlining so make sure they stay valid. */
if (in_ipa_mode
&& !DECL_PT_UID_SET_P (vi->decl))
SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
/* Add the decl to the points-to set. Note that the points-to
set contains global variables. */
bitmap_set_bit (into, DECL_PT_UID (vi->decl));
if (vi->is_global_var
/* In IPA mode the escaped_heap trick doesn't work as
ESCAPED is escaped from the unit but
pt_solution_includes_global needs to answer true for
all variables not automatic within a function.
For the same reason is_global_var is not the
correct flag to track - local variables from other
functions also need to be considered global.
Conveniently all HEAP vars are not put in function
scope. */
|| (in_ipa_mode
&& fndecl
&& ! auto_var_in_fn_p (vi->decl, fndecl)))
pt->vars_contains_nonlocal = true;
/* If we have a variable that is interposable record that fact
for pointer comparison simplification. */
if (VAR_P (vi->decl)
&& (TREE_STATIC (vi->decl) || DECL_EXTERNAL (vi->decl))
&& ! decl_binds_to_current_def_p (vi->decl))
pt->vars_contains_interposable = true;
/* If this is a local variable we can have overlapping lifetime
of different function invocations through recursion duplicate
it with its shadow variable. */
if (in_ipa_mode
&& vi->shadow_var_uid != 0)
{
bitmap_set_bit (into, vi->shadow_var_uid);
pt->vars_contains_nonlocal = true;
}
}
else if (TREE_CODE (vi->decl) == FUNCTION_DECL
|| TREE_CODE (vi->decl) == LABEL_DECL)
{
/* Nothing should read/write from/to code so we can
save bits by not including them in the points-to bitmaps.
Still mark the points-to set as containing global memory
to make code-patching possible - see PR70128. */
pt->vars_contains_nonlocal = true;
}
}
}
/* Compute the points-to solution *PT for the variable VI. */
static struct pt_solution
find_what_var_points_to (tree fndecl, varinfo_t orig_vi)
{
unsigned int i;
bitmap_iterator bi;
bitmap finished_solution;
bitmap result;
varinfo_t vi;
struct pt_solution *pt;
/* This variable may have been collapsed, let's get the real
variable. */
vi = get_varinfo (find (orig_vi->id));
/* See if we have already computed the solution and return it. */
pt_solution **slot = &final_solutions->get_or_insert (vi);
if (*slot != NULL)
return **slot;
*slot = pt = XOBNEW (&final_solutions_obstack, struct pt_solution);
memset (pt, 0, sizeof (struct pt_solution));
/* Translate artificial variables into SSA_NAME_PTR_INFO
attributes. */
EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
{
varinfo_t vi = get_varinfo (i);
if (vi->is_artificial_var)
{
if (vi->id == nothing_id)
pt->null = 1;
else if (vi->id == escaped_id)
{
if (in_ipa_mode)
pt->ipa_escaped = 1;
else
pt->escaped = 1;
/* Expand some special vars of ESCAPED in-place here. */
varinfo_t evi = get_varinfo (find (escaped_id));
if (bitmap_bit_p (evi->solution, nonlocal_id))
pt->nonlocal = 1;
}
else if (vi->id == nonlocal_id)
pt->nonlocal = 1;
else if (vi->id == string_id)
/* Nobody cares - STRING_CSTs are read-only entities. */
;
else if (vi->id == anything_id
|| vi->id == integer_id)
pt->anything = 1;
}
}
/* Instead of doing extra work, simply do not create
elaborate points-to information for pt_anything pointers. */
if (pt->anything)
return *pt;
/* Share the final set of variables when possible. */
finished_solution = BITMAP_GGC_ALLOC ();
stats.points_to_sets_created++;
set_uids_in_ptset (finished_solution, vi->solution, pt, fndecl);
result = shared_bitmap_lookup (finished_solution);
if (!result)
{
shared_bitmap_add (finished_solution);
pt->vars = finished_solution;
}
else
{
pt->vars = result;
bitmap_clear (finished_solution);
}
return *pt;
}
/* Given a pointer variable P, fill in its points-to set. */
static void
find_what_p_points_to (tree fndecl, tree p)
{
struct ptr_info_def *pi;
tree lookup_p = p;
varinfo_t vi;
value_range vr;
get_range_query (DECL_STRUCT_FUNCTION (fndecl))->range_of_expr (vr, p);
bool nonnull = vr.nonzero_p ();
/* For parameters, get at the points-to set for the actual parm
decl. */
if (TREE_CODE (p) == SSA_NAME
&& SSA_NAME_IS_DEFAULT_DEF (p)
&& (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
|| TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL))
lookup_p = SSA_NAME_VAR (p);
vi = lookup_vi_for_tree (lookup_p);
if (!vi)
return;
pi = get_ptr_info (p);
pi->pt = find_what_var_points_to (fndecl, vi);
/* Conservatively set to NULL from PTA (to true). */
pi->pt.null = 1;
/* Preserve pointer nonnull globally computed. */
if (nonnull)
set_ptr_nonnull (p);
}
/* Query statistics for points-to solutions. */
static struct {
unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
} pta_stats;
void
dump_pta_stats (FILE *s)
{
fprintf (s, "\nPTA query stats:\n");
fprintf (s, " pt_solution_includes: "
HOST_WIDE_INT_PRINT_DEC" disambiguations, "
HOST_WIDE_INT_PRINT_DEC" queries\n",
pta_stats.pt_solution_includes_no_alias,
pta_stats.pt_solution_includes_no_alias
+ pta_stats.pt_solution_includes_may_alias);
fprintf (s, " pt_solutions_intersect: "
HOST_WIDE_INT_PRINT_DEC" disambiguations, "
HOST_WIDE_INT_PRINT_DEC" queries\n",
pta_stats.pt_solutions_intersect_no_alias,
pta_stats.pt_solutions_intersect_no_alias
+ pta_stats.pt_solutions_intersect_may_alias);
}
/* Reset the points-to solution *PT to a conservative default
(point to anything). */
void
pt_solution_reset (struct pt_solution *pt)
{
memset (pt, 0, sizeof (struct pt_solution));
pt->anything = true;
pt->null = true;
}
/* Set the points-to solution *PT to point only to the variables
in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
global variables and VARS_CONTAINS_RESTRICT specifies whether
it contains restrict tag variables. */
void
pt_solution_set (struct pt_solution *pt, bitmap vars,
bool vars_contains_nonlocal)
{
memset (pt, 0, sizeof (struct pt_solution));
pt->vars = vars;
pt->vars_contains_nonlocal = vars_contains_nonlocal;
pt->vars_contains_escaped
= (cfun->gimple_df->escaped.anything
|| bitmap_intersect_p (cfun->gimple_df->escaped.vars, vars));
}
/* Set the points-to solution *PT to point only to the variable VAR. */
void
pt_solution_set_var (struct pt_solution *pt, tree var)
{
memset (pt, 0, sizeof (struct pt_solution));
pt->vars = BITMAP_GGC_ALLOC ();
bitmap_set_bit (pt->vars, DECL_PT_UID (var));
pt->vars_contains_nonlocal = is_global_var (var);
pt->vars_contains_escaped
= (cfun->gimple_df->escaped.anything
|| bitmap_bit_p (cfun->gimple_df->escaped.vars, DECL_PT_UID (var)));
}
/* Computes the union of the points-to solutions *DEST and *SRC and
stores the result in *DEST. This changes the points-to bitmap
of *DEST and thus may not be used if that might be shared.
The points-to bitmap of *SRC and *DEST will not be shared after
this function if they were not before. */
static void
pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
{
dest->anything |= src->anything;
if (dest->anything)
{
pt_solution_reset (dest);
return;
}
dest->nonlocal |= src->nonlocal;
dest->escaped |= src->escaped;
dest->ipa_escaped |= src->ipa_escaped;
dest->null |= src->null;
dest->vars_contains_nonlocal |= src->vars_contains_nonlocal;
dest->vars_contains_escaped |= src->vars_contains_escaped;
dest->vars_contains_escaped_heap |= src->vars_contains_escaped_heap;
if (!src->vars)
return;
if (!dest->vars)
dest->vars = BITMAP_GGC_ALLOC ();
bitmap_ior_into (dest->vars, src->vars);
}
/* Return true if the points-to solution *PT is empty. */
bool
pt_solution_empty_p (const pt_solution *pt)
{
if (pt->anything
|| pt->nonlocal)
return false;
if (pt->vars
&& !bitmap_empty_p (pt->vars))
return false;
/* If the solution includes ESCAPED, check if that is empty. */
if (pt->escaped
&& !pt_solution_empty_p (&cfun->gimple_df->escaped))
return false;
/* If the solution includes ESCAPED, check if that is empty. */
if (pt->ipa_escaped
&& !pt_solution_empty_p (&ipa_escaped_pt))
return false;
return true;
}
/* Return true if the points-to solution *PT only point to a single var, and
return the var uid in *UID. */
bool
pt_solution_singleton_or_null_p (struct pt_solution *pt, unsigned *uid)
{
if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped
|| pt->vars == NULL
|| !bitmap_single_bit_set_p (pt->vars))
return false;
*uid = bitmap_first_set_bit (pt->vars);
return true;
}
/* Return true if the points-to solution *PT includes global memory.
If ESCAPED_LOCAL_P is true then escaped local variables are also
considered global. */
bool
pt_solution_includes_global (struct pt_solution *pt, bool escaped_local_p)
{
if (pt->anything
|| pt->nonlocal
|| pt->vars_contains_nonlocal
/* The following is a hack to make the malloc escape hack work.
In reality we'd need different sets for escaped-through-return
and escaped-to-callees and passes would need to be updated. */
|| pt->vars_contains_escaped_heap)
return true;
if (escaped_local_p && pt->vars_contains_escaped)
return true;
/* 'escaped' is also a placeholder so we have to look into it. */
if (pt->escaped)
return pt_solution_includes_global (&cfun->gimple_df->escaped,
escaped_local_p);
if (pt->ipa_escaped)
return pt_solution_includes_global (&ipa_escaped_pt,
escaped_local_p);
return false;
}
/* Return true if the points-to solution *PT includes the variable
declaration DECL. */
static bool
pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
{
if (pt->anything)
return true;
if (pt->nonlocal
&& is_global_var (decl))
return true;
if (pt->vars
&& bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
return true;
/* If the solution includes ESCAPED, check it. */
if (pt->escaped
&& pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
return true;
/* If the solution includes ESCAPED, check it. */
if (pt->ipa_escaped
&& pt_solution_includes_1 (&ipa_escaped_pt, decl))
return true;
return false;
}
bool
pt_solution_includes (struct pt_solution *pt, const_tree decl)
{
bool res = pt_solution_includes_1 (pt, decl);
if (res)
++pta_stats.pt_solution_includes_may_alias;
else
++pta_stats.pt_solution_includes_no_alias;
return res;
}
/* Return true if both points-to solutions PT1 and PT2 have a non-empty
intersection. */
static bool
pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
{
if (pt1->anything || pt2->anything)
return true;
/* If either points to unknown global memory and the other points to
any global memory they alias. */
if ((pt1->nonlocal
&& (pt2->nonlocal
|| pt2->vars_contains_nonlocal))
|| (pt2->nonlocal
&& pt1->vars_contains_nonlocal))
return true;
/* If either points to all escaped memory and the other points to
any escaped memory they alias. */
if ((pt1->escaped
&& (pt2->escaped
|| pt2->vars_contains_escaped))
|| (pt2->escaped
&& pt1->vars_contains_escaped))
return true;
/* Check the escaped solution if required.
??? Do we need to check the local against the IPA escaped sets? */
if ((pt1->ipa_escaped || pt2->ipa_escaped)
&& !pt_solution_empty_p (&ipa_escaped_pt))
{
/* If both point to escaped memory and that solution
is not empty they alias. */
if (pt1->ipa_escaped && pt2->ipa_escaped)
return true;
/* If either points to escaped memory see if the escaped solution
intersects with the other. */
if ((pt1->ipa_escaped
&& pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
|| (pt2->ipa_escaped
&& pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
return true;
}
/* Now both pointers alias if their points-to solution intersects. */
return (pt1->vars
&& pt2->vars
&& bitmap_intersect_p (pt1->vars, pt2->vars));
}
bool
pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
{
bool res = pt_solutions_intersect_1 (pt1, pt2);
if (res)
++pta_stats.pt_solutions_intersect_may_alias;
else
++pta_stats.pt_solutions_intersect_no_alias;
return res;
}
/* Dump points-to information to OUTFILE. */
static void
dump_sa_points_to_info (FILE *outfile)
{
unsigned int i;
fprintf (outfile, "\nPoints-to sets\n\n");
if (dump_flags & TDF_STATS)
{
fprintf (outfile, "Stats:\n");
fprintf (outfile, "Total vars: %d\n", stats.total_vars);
fprintf (outfile, "Non-pointer vars: %d\n",
stats.nonpointer_vars);
fprintf (outfile, "Statically unified vars: %d\n",
stats.unified_vars_static);
fprintf (outfile, "Dynamically unified vars: %d\n",
stats.unified_vars_dynamic);
fprintf (outfile, "Iterations: %d\n", stats.iterations);
fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
fprintf (outfile, "Number of implicit edges: %d\n",
stats.num_implicit_edges);
}
for (i = 1; i < varmap.length (); i++)
{
varinfo_t vi = get_varinfo (i);
if (!vi->may_have_pointers)
continue;
dump_solution_for_var (outfile, i);
}
}
/* Debug points-to information to stderr. */
DEBUG_FUNCTION void
debug_sa_points_to_info (void)
{
dump_sa_points_to_info (stderr);
}
/* Initialize the always-existing constraint variables for NULL
ANYTHING, READONLY, and INTEGER */
static void
init_base_vars (void)
{
struct constraint_expr lhs, rhs;
varinfo_t var_anything;
varinfo_t var_nothing;
varinfo_t var_string;
varinfo_t var_escaped;
varinfo_t var_nonlocal;
varinfo_t var_storedanything;
varinfo_t var_integer;
/* Variable ID zero is reserved and should be NULL. */
varmap.safe_push (NULL);
/* Create the NULL variable, used to represent that a variable points
to NULL. */
var_nothing = new_var_info (NULL_TREE, "NULL", false);
gcc_assert (var_nothing->id == nothing_id);
var_nothing->is_artificial_var = 1;
var_nothing->offset = 0;
var_nothing->size = ~0;
var_nothing->fullsize = ~0;
var_nothing->is_special_var = 1;
var_nothing->may_have_pointers = 0;
var_nothing->is_global_var = 0;
/* Create the ANYTHING variable, used to represent that a variable
points to some unknown piece of memory. */
var_anything = new_var_info (NULL_TREE, "ANYTHING", false);
gcc_assert (var_anything->id == anything_id);
var_anything->is_artificial_var = 1;
var_anything->size = ~0;
var_anything->offset = 0;
var_anything->fullsize = ~0;
var_anything->is_special_var = 1;
/* Anything points to anything. This makes deref constraints just
work in the presence of linked list and other p = *p type loops,
by saying that *ANYTHING = ANYTHING. */
lhs.type = SCALAR;
lhs.var = anything_id;
lhs.offset = 0;
rhs.type = ADDRESSOF;
rhs.var = anything_id;
rhs.offset = 0;
/* This specifically does not use process_constraint because
process_constraint ignores all anything = anything constraints, since all
but this one are redundant. */
constraints.safe_push (new_constraint (lhs, rhs));
/* Create the STRING variable, used to represent that a variable
points to a string literal. String literals don't contain
pointers so STRING doesn't point to anything. */
var_string = new_var_info (NULL_TREE, "STRING", false);
gcc_assert (var_string->id == string_id);
var_string->is_artificial_var = 1;
var_string->offset = 0;
var_string->size = ~0;
var_string->fullsize = ~0;
var_string->is_special_var = 1;
var_string->may_have_pointers = 0;
/* Create the ESCAPED variable, used to represent the set of escaped
memory. */
var_escaped = new_var_info (NULL_TREE, "ESCAPED", false);
gcc_assert (var_escaped->id == escaped_id);
var_escaped->is_artificial_var = 1;
var_escaped->offset = 0;
var_escaped->size = ~0;
var_escaped->fullsize = ~0;
var_escaped->is_special_var = 0;
/* Create the NONLOCAL variable, used to represent the set of nonlocal
memory. */
var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL", false);
gcc_assert (var_nonlocal->id == nonlocal_id);
var_nonlocal->is_artificial_var = 1;
var_nonlocal->offset = 0;
var_nonlocal->size = ~0;
var_nonlocal->fullsize = ~0;
var_nonlocal->is_special_var = 1;
/* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
lhs.type = SCALAR;
lhs.var = escaped_id;
lhs.offset = 0;
rhs.type = DEREF;
rhs.var = escaped_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
/* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
whole variable escapes. */
lhs.type = SCALAR;
lhs.var = escaped_id;
lhs.offset = 0;
rhs.type = SCALAR;
rhs.var = escaped_id;
rhs.offset = UNKNOWN_OFFSET;
process_constraint (new_constraint (lhs, rhs));
/* *ESCAPED = NONLOCAL. This is true because we have to assume
everything pointed to by escaped points to what global memory can
point to. */
lhs.type = DEREF;
lhs.var = escaped_id;
lhs.offset = 0;
rhs.type = SCALAR;
rhs.var = nonlocal_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
/* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
global memory may point to global memory and escaped memory. */
lhs.type = SCALAR;
lhs.var = nonlocal_id;
lhs.offset = 0;
rhs.type = ADDRESSOF;
rhs.var = nonlocal_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
rhs.type = ADDRESSOF;
rhs.var = escaped_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
/* Create the STOREDANYTHING variable, used to represent the set of
variables stored to *ANYTHING. */
var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING", false);
gcc_assert (var_storedanything->id == storedanything_id);
var_storedanything->is_artificial_var = 1;
var_storedanything->offset = 0;
var_storedanything->size = ~0;
var_storedanything->fullsize = ~0;
var_storedanything->is_special_var = 0;
/* Create the INTEGER variable, used to represent that a variable points
to what an INTEGER "points to". */
var_integer = new_var_info (NULL_TREE, "INTEGER", false);
gcc_assert (var_integer->id == integer_id);
var_integer->is_artificial_var = 1;
var_integer->size = ~0;
var_integer->fullsize = ~0;
var_integer->offset = 0;
var_integer->is_special_var = 1;
/* INTEGER = ANYTHING, because we don't know where a dereference of
a random integer will point to. */
lhs.type = SCALAR;
lhs.var = integer_id;
lhs.offset = 0;
rhs.type = ADDRESSOF;
rhs.var = anything_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
}
/* Initialize things necessary to perform PTA */
static void
init_alias_vars (void)
{
use_field_sensitive = (param_max_fields_for_field_sensitive > 1);
bitmap_obstack_initialize (&pta_obstack);
bitmap_obstack_initialize (&oldpta_obstack);
bitmap_obstack_initialize (&predbitmap_obstack);
constraints.create (8);
varmap.create (8);
vi_for_tree = new hash_map<tree, varinfo_t>;
call_stmt_vars = new hash_map<gimple *, varinfo_t>;
memset (&stats, 0, sizeof (stats));
shared_bitmap_table = new hash_table<shared_bitmap_hasher> (511);
init_base_vars ();
gcc_obstack_init (&fake_var_decl_obstack);
final_solutions = new hash_map<varinfo_t, pt_solution *>;
gcc_obstack_init (&final_solutions_obstack);
}
/* Remove the REF and ADDRESS edges from GRAPH, as well as all the
predecessor edges. */
static void
remove_preds_and_fake_succs (constraint_graph_t graph)
{
unsigned int i;
/* Clear the implicit ref and address nodes from the successor
lists. */
for (i = 1; i < FIRST_REF_NODE; i++)
{
if (graph->succs[i])
bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
FIRST_REF_NODE * 2);
}
/* Free the successor list for the non-ref nodes. */
for (i = FIRST_REF_NODE + 1; i < graph->size; i++)
{
if (graph->succs[i])
BITMAP_FREE (graph->succs[i]);
}
/* Now reallocate the size of the successor list as, and blow away
the predecessor bitmaps. */
graph->size = varmap.length ();
graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
free (graph->implicit_preds);
graph->implicit_preds = NULL;
free (graph->preds);
graph->preds = NULL;
bitmap_obstack_release (&predbitmap_obstack);
}
/* Solve the constraint set. */
static void
solve_constraints (void)
{
class scc_info *si;
/* Sort varinfos so that ones that cannot be pointed to are last.
This makes bitmaps more efficient. */
unsigned int *map = XNEWVEC (unsigned int, varmap.length ());
for (unsigned i = 0; i < integer_id + 1; ++i)
map[i] = i;
/* Start with address-taken vars, followed by not address-taken vars
to move vars never appearing in the points-to solution bitmaps last. */
unsigned j = integer_id + 1;
for (unsigned i = integer_id + 1; i < varmap.length (); ++i)
if (varmap[varmap[i]->head]->address_taken)
map[i] = j++;
for (unsigned i = integer_id + 1; i < varmap.length (); ++i)
if (! varmap[varmap[i]->head]->address_taken)
map[i] = j++;
/* Shuffle varmap according to map. */
for (unsigned i = integer_id + 1; i < varmap.length (); ++i)
{
while (map[varmap[i]->id] != i)
std::swap (varmap[i], varmap[map[varmap[i]->id]]);
gcc_assert (bitmap_empty_p (varmap[i]->solution));
varmap[i]->id = i;
varmap[i]->next = map[varmap[i]->next];
varmap[i]->head = map[varmap[i]->head];
}
/* Finally rewrite constraints. */
for (unsigned i = 0; i < constraints.length (); ++i)
{
constraints[i]->lhs.var = map[constraints[i]->lhs.var];
constraints[i]->rhs.var = map[constraints[i]->rhs.var];
}
free (map);
if (dump_file)
fprintf (dump_file,
"\nCollapsing static cycles and doing variable "
"substitution\n");
init_graph (varmap.length () * 2);
if (dump_file)
fprintf (dump_file, "Building predecessor graph\n");
build_pred_graph ();
if (dump_file)
fprintf (dump_file, "Detecting pointer and location "
"equivalences\n");
si = perform_var_substitution (graph);
if (dump_file)
fprintf (dump_file, "Rewriting constraints and unifying "
"variables\n");
rewrite_constraints (graph, si);
build_succ_graph ();
free_var_substitution_info (si);
/* Attach complex constraints to graph nodes. */
move_complex_constraints (graph);
if (dump_file)
fprintf (dump_file, "Uniting pointer but not location equivalent "
"variables\n");
unite_pointer_equivalences (graph);
if (dump_file)
fprintf (dump_file, "Finding indirect cycles\n");
find_indirect_cycles (graph);
/* Implicit nodes and predecessors are no longer necessary at this
point. */
remove_preds_and_fake_succs (graph);
if (dump_file && (dump_flags & TDF_GRAPH))
{
fprintf (dump_file, "\n\n// The constraint graph before solve-graph "
"in dot format:\n");
dump_constraint_graph (dump_file);
fprintf (dump_file, "\n\n");
}
if (dump_file)
fprintf (dump_file, "Solving graph\n");
solve_graph (graph);
if (dump_file && (dump_flags & TDF_GRAPH))
{
fprintf (dump_file, "\n\n// The constraint graph after solve-graph "
"in dot format:\n");
dump_constraint_graph (dump_file);
fprintf (dump_file, "\n\n");
}
}
/* Create points-to sets for the current function. See the comments
at the start of the file for an algorithmic overview. */
static void
compute_points_to_sets (void)
{
basic_block bb;
varinfo_t vi;
timevar_push (TV_TREE_PTA);
init_alias_vars ();
intra_create_variable_infos (cfun);
/* Now walk all statements and build the constraint set. */
FOR_EACH_BB_FN (bb, cfun)
{
for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
gsi_next (&gsi))
{
gphi *phi = gsi.phi ();
if (! virtual_operand_p (gimple_phi_result (phi)))
find_func_aliases (cfun, phi);
}
for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);
gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
find_func_aliases (cfun, stmt);
}
}
if (dump_file)
{
fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
dump_constraints (dump_file, 0);
}
/* From the constraints compute the points-to sets. */
solve_constraints ();
/* Post-process solutions for escapes through returns. */
edge_iterator ei;
edge e;
FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)
if (greturn *ret = safe_dyn_cast <greturn *> (last_stmt (e->src)))
{
tree val = gimple_return_retval (ret);
/* ??? Easy to handle simple indirections with some work.
Arbitrary references like foo.bar.baz are more difficult
(but conservatively easy enough with just looking at the base).
Mind to fixup find_func_aliases as well. */
if (!val || !SSA_VAR_P (val))
continue;
/* returns happen last in non-IPA so they only influence
the ESCAPED solution and we can filter local variables. */
varinfo_t escaped_vi = get_varinfo (find (escaped_id));
varinfo_t vi = lookup_vi_for_tree (val);
bitmap delta = BITMAP_ALLOC (&pta_obstack);
bitmap_iterator bi;
unsigned i;
for (; vi; vi = vi_next (vi))
{
varinfo_t part_vi = get_varinfo (find (vi->id));
EXECUTE_IF_AND_COMPL_IN_BITMAP (part_vi->solution,
escaped_vi->solution, 0, i, bi)
{
varinfo_t pointed_to_vi = get_varinfo (i);
if (pointed_to_vi->is_global_var
/* We delay marking of heap memory as global. */
|| pointed_to_vi->is_heap_var)
bitmap_set_bit (delta, i);
}
}
/* Now compute the transitive closure. */
bitmap_ior_into (escaped_vi->solution, delta);
bitmap new_delta = BITMAP_ALLOC (&pta_obstack);
while (!bitmap_empty_p (delta))
{
EXECUTE_IF_SET_IN_BITMAP (delta, 0, i, bi)
{
varinfo_t pointed_to_vi = get_varinfo (i);
pointed_to_vi = get_varinfo (find (pointed_to_vi->id));
unsigned j;
bitmap_iterator bi2;
EXECUTE_IF_AND_COMPL_IN_BITMAP (pointed_to_vi->solution,
escaped_vi->solution,
0, j, bi2)
{
varinfo_t pointed_to_vi2 = get_varinfo (j);
if (pointed_to_vi2->is_global_var
/* We delay marking of heap memory as global. */
|| pointed_to_vi2->is_heap_var)
bitmap_set_bit (new_delta, j);
}
}
bitmap_ior_into (escaped_vi->solution, new_delta);
bitmap_clear (delta);
std::swap (delta, new_delta);
}
BITMAP_FREE (delta);
BITMAP_FREE (new_delta);
}
if (dump_file)
dump_sa_points_to_info (dump_file);
/* Compute the points-to set for ESCAPED used for call-clobber analysis. */
cfun->gimple_df->escaped = find_what_var_points_to (cfun->decl,
get_varinfo (escaped_id));
/* Make sure the ESCAPED solution (which is used as placeholder in
other solutions) does not reference itself. This simplifies
points-to solution queries. */
cfun->gimple_df->escaped.escaped = 0;
/* Compute the points-to sets for pointer SSA_NAMEs. */
unsigned i;
tree ptr;
FOR_EACH_SSA_NAME (i, ptr, cfun)
{
if (POINTER_TYPE_P (TREE_TYPE (ptr)))
find_what_p_points_to (cfun->decl, ptr);
}
/* Compute the call-used/clobbered sets. */
FOR_EACH_BB_FN (bb, cfun)
{
gimple_stmt_iterator gsi;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gcall *stmt;
struct pt_solution *pt;
stmt = dyn_cast <gcall *> (gsi_stmt (gsi));
if (!stmt)
continue;
pt = gimple_call_use_set (stmt);
if (gimple_call_flags (stmt) & ECF_CONST)
memset (pt, 0, sizeof (struct pt_solution));
else
{
bool uses_global_memory = true;
bool reads_global_memory = true;
determine_global_memory_access (stmt, NULL,
&reads_global_memory,
&uses_global_memory);
if ((vi = lookup_call_use_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (cfun->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly used by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
if (uses_global_memory)
{
pt->nonlocal = 1;
pt->escaped = 1;
}
}
else if (uses_global_memory)
{
/* If there is nothing special about this call then
we have made everything that is used also escape. */
*pt = cfun->gimple_df->escaped;
pt->nonlocal = 1;
}
else
memset (pt, 0, sizeof (struct pt_solution));
}
pt = gimple_call_clobber_set (stmt);
if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
memset (pt, 0, sizeof (struct pt_solution));
else
{
bool writes_global_memory = true;
determine_global_memory_access (stmt, &writes_global_memory,
NULL, NULL);
if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (cfun->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly clobbered by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
if (writes_global_memory)
{
pt->nonlocal = 1;
pt->escaped = 1;
}
}
else if (writes_global_memory)
{
/* If there is nothing special about this call then
we have made everything that is used also escape. */
*pt = cfun->gimple_df->escaped;
pt->nonlocal = 1;
}
else
memset (pt, 0, sizeof (struct pt_solution));
}
}
}
timevar_pop (TV_TREE_PTA);
}
/* Delete created points-to sets. */
static void
delete_points_to_sets (void)
{
unsigned int i;
delete shared_bitmap_table;
shared_bitmap_table = NULL;
if (dump_file && (dump_flags & TDF_STATS))
fprintf (dump_file, "Points to sets created:%d\n",
stats.points_to_sets_created);
delete vi_for_tree;
delete call_stmt_vars;
bitmap_obstack_release (&pta_obstack);
constraints.release ();
for (i = 0; i < graph->size; i++)
graph->complex[i].release ();
free (graph->complex);
free (graph->rep);
free (graph->succs);
free (graph->pe);
free (graph->pe_rep);
free (graph->indirect_cycles);
free (graph);
varmap.release ();
variable_info_pool.release ();
constraint_pool.release ();
obstack_free (&fake_var_decl_obstack, NULL);
delete final_solutions;
obstack_free (&final_solutions_obstack, NULL);
}
struct vls_data
{
unsigned short clique;
bool escaped_p;
bitmap rvars;
};
/* Mark "other" loads and stores as belonging to CLIQUE and with
base zero. */
static bool
visit_loadstore (gimple *, tree base, tree ref, void *data)
{
unsigned short clique = ((vls_data *) data)->clique;
bitmap rvars = ((vls_data *) data)->rvars;
bool escaped_p = ((vls_data *) data)->escaped_p;
if (TREE_CODE (base) == MEM_REF
|| TREE_CODE (base) == TARGET_MEM_REF)
{
tree ptr = TREE_OPERAND (base, 0);
if (TREE_CODE (ptr) == SSA_NAME)
{
/* For parameters, get at the points-to set for the actual parm
decl. */
if (SSA_NAME_IS_DEFAULT_DEF (ptr)
&& (TREE_CODE (SSA_NAME_VAR (ptr)) == PARM_DECL
|| TREE_CODE (SSA_NAME_VAR (ptr)) == RESULT_DECL))
ptr = SSA_NAME_VAR (ptr);
/* We need to make sure 'ptr' doesn't include any of
the restrict tags we added bases for in its points-to set. */
varinfo_t vi = lookup_vi_for_tree (ptr);
if (! vi)
return false;
vi = get_varinfo (find (vi->id));
if (bitmap_intersect_p (rvars, vi->solution)
|| (escaped_p && bitmap_bit_p (vi->solution, escaped_id)))
return false;
}
/* Do not overwrite existing cliques (that includes clique, base
pairs we just set). */
if (MR_DEPENDENCE_CLIQUE (base) == 0)
{
MR_DEPENDENCE_CLIQUE (base) = clique;
MR_DEPENDENCE_BASE (base) = 0;
}
}
/* For plain decl accesses see whether they are accesses to globals
and rewrite them to MEM_REFs with { clique, 0 }. */
if (VAR_P (base)
&& is_global_var (base)
/* ??? We can't rewrite a plain decl with the walk_stmt_load_store
ops callback. */
&& base != ref)
{
tree *basep = &ref;
while (handled_component_p (*basep))
basep = &TREE_OPERAND (*basep, 0);
gcc_assert (VAR_P (*basep));
tree ptr = build_fold_addr_expr (*basep);
tree zero = build_int_cst (TREE_TYPE (ptr), 0);
*basep = build2 (MEM_REF, TREE_TYPE (*basep), ptr, zero);
MR_DEPENDENCE_CLIQUE (*basep) = clique;
MR_DEPENDENCE_BASE (*basep) = 0;
}
return false;
}
struct msdi_data {
tree ptr;
unsigned short *clique;
unsigned short *last_ruid;
varinfo_t restrict_var;
};
/* If BASE is a MEM_REF then assign a clique, base pair to it, updating
CLIQUE, *RESTRICT_VAR and LAST_RUID as passed via DATA.
Return whether dependence info was assigned to BASE. */
static bool
maybe_set_dependence_info (gimple *, tree base, tree, void *data)
{
tree ptr = ((msdi_data *)data)->ptr;
unsigned short &clique = *((msdi_data *)data)->clique;
unsigned short &last_ruid = *((msdi_data *)data)->last_ruid;
varinfo_t restrict_var = ((msdi_data *)data)->restrict_var;
if ((TREE_CODE (base) == MEM_REF
|| TREE_CODE (base) == TARGET_MEM_REF)
&& TREE_OPERAND (base, 0) == ptr)
{
/* Do not overwrite existing cliques. This avoids overwriting dependence
info inlined from a function with restrict parameters inlined
into a function with restrict parameters. This usually means we
prefer to be precise in innermost loops. */
if (MR_DEPENDENCE_CLIQUE (base) == 0)
{
if (clique == 0)
{
if (cfun->last_clique == 0)
cfun->last_clique = 1;
clique = 1;
}
if (restrict_var->ruid == 0)
restrict_var->ruid = ++last_ruid;
MR_DEPENDENCE_CLIQUE (base) = clique;
MR_DEPENDENCE_BASE (base) = restrict_var->ruid;
return true;
}
}
return false;
}
/* Clear dependence info for the clique DATA. */
static bool
clear_dependence_clique (gimple *, tree base, tree, void *data)
{
unsigned short clique = (uintptr_t)data;
if ((TREE_CODE (base) == MEM_REF
|| TREE_CODE (base) == TARGET_MEM_REF)
&& MR_DEPENDENCE_CLIQUE (base) == clique)
{
MR_DEPENDENCE_CLIQUE (base) = 0;
MR_DEPENDENCE_BASE (base) = 0;
}
return false;
}
/* Compute the set of independend memory references based on restrict
tags and their conservative propagation to the points-to sets. */
static void
compute_dependence_clique (void)
{
/* First clear the special "local" clique. */
basic_block bb;
if (cfun->last_clique != 0)
FOR_EACH_BB_FN (bb, cfun)
for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
!gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
walk_stmt_load_store_ops (stmt, (void *)(uintptr_t) 1,
clear_dependence_clique,
clear_dependence_clique);
}
unsigned short clique = 0;
unsigned short last_ruid = 0;
bitmap rvars = BITMAP_ALLOC (NULL);
bool escaped_p = false;
for (unsigned i = 0; i < num_ssa_names; ++i)
{
tree ptr = ssa_name (i);
if (!ptr || !POINTER_TYPE_P (TREE_TYPE (ptr)))
continue;
/* Avoid all this when ptr is not dereferenced? */
tree p = ptr;
if (SSA_NAME_IS_DEFAULT_DEF (ptr)
&& (TREE_CODE (SSA_NAME_VAR (ptr)) == PARM_DECL
|| TREE_CODE (SSA_NAME_VAR (ptr)) == RESULT_DECL))
p = SSA_NAME_VAR (ptr);
varinfo_t vi = lookup_vi_for_tree (p);
if (!vi)
continue;
vi = get_varinfo (find (vi->id));
bitmap_iterator bi;
unsigned j;
varinfo_t restrict_var = NULL;
EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, j, bi)
{
varinfo_t oi = get_varinfo (j);
if (oi->head != j)
oi = get_varinfo (oi->head);
if (oi->is_restrict_var)
{
if (restrict_var
&& restrict_var != oi)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "found restrict pointed-to "
"for ");
print_generic_expr (dump_file, ptr);
fprintf (dump_file, " but not exclusively\n");
}
restrict_var = NULL;
break;
}
restrict_var = oi;
}
/* NULL is the only other valid points-to entry. */
else if (oi->id != nothing_id)
{
restrict_var = NULL;
break;
}
}
/* Ok, found that ptr must(!) point to a single(!) restrict
variable. */
/* ??? PTA isn't really a proper propagation engine to compute
this property.
??? We could handle merging of two restricts by unifying them. */
if (restrict_var)
{
/* Now look at possible dereferences of ptr. */
imm_use_iterator ui;
gimple *use_stmt;
bool used = false;
msdi_data data = { ptr, &clique, &last_ruid, restrict_var };
FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr)
used |= walk_stmt_load_store_ops (use_stmt, &data,
maybe_set_dependence_info,
maybe_set_dependence_info);
if (used)
{
/* Add all subvars to the set of restrict pointed-to set. */
for (unsigned sv = restrict_var->head; sv != 0;
sv = get_varinfo (sv)->next)
bitmap_set_bit (rvars, sv);
varinfo_t escaped = get_varinfo (find (escaped_id));
if (bitmap_bit_p (escaped->solution, restrict_var->id))
escaped_p = true;
}
}
}
if (clique != 0)
{
/* Assign the BASE id zero to all accesses not based on a restrict
pointer. That way they get disambiguated against restrict
accesses but not against each other. */
/* ??? For restricts derived from globals (thus not incoming
parameters) we can't restrict scoping properly thus the following
is too aggressive there. For now we have excluded those globals from
getting into the MR_DEPENDENCE machinery. */
vls_data data = { clique, escaped_p, rvars };
basic_block bb;
FOR_EACH_BB_FN (bb, cfun)
for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
!gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
walk_stmt_load_store_ops (stmt, &data,
visit_loadstore, visit_loadstore);
}
}
BITMAP_FREE (rvars);
}
/* Compute points-to information for every SSA_NAME pointer in the
current function and compute the transitive closure of escaped
variables to re-initialize the call-clobber states of local variables. */
unsigned int
compute_may_aliases (void)
{
if (cfun->gimple_df->ipa_pta)
{
if (dump_file)
{
fprintf (dump_file, "\nNot re-computing points-to information "
"because IPA points-to information is available.\n\n");
/* But still dump what we have remaining it. */
dump_alias_info (dump_file);
}
return 0;
}
/* For each pointer P_i, determine the sets of variables that P_i may
point-to. Compute the reachability set of escaped and call-used
variables. */
compute_points_to_sets ();
/* Debugging dumps. */
if (dump_file)
dump_alias_info (dump_file);
/* Compute restrict-based memory disambiguations. */
compute_dependence_clique ();
/* Deallocate memory used by aliasing data structures and the internal
points-to solution. */
delete_points_to_sets ();
gcc_assert (!need_ssa_update_p (cfun));
return 0;
}
/* A dummy pass to cause points-to information to be computed via
TODO_rebuild_alias. */
namespace {
const pass_data pass_data_build_alias =
{
GIMPLE_PASS, /* type */
"alias", /* name */
OPTGROUP_NONE, /* optinfo_flags */
TV_NONE, /* tv_id */
( PROP_cfg | PROP_ssa ), /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_rebuild_alias, /* todo_flags_finish */
};
class pass_build_alias : public gimple_opt_pass
{
public:
pass_build_alias (gcc::context *ctxt)
: gimple_opt_pass (pass_data_build_alias, ctxt)
{}
/* opt_pass methods: */
bool gate (function *) final override { return flag_tree_pta; }
}; // class pass_build_alias
} // anon namespace
gimple_opt_pass *
make_pass_build_alias (gcc::context *ctxt)
{
return new pass_build_alias (ctxt);
}
/* A dummy pass to cause points-to information to be computed via
TODO_rebuild_alias. */
namespace {
const pass_data pass_data_build_ealias =
{
GIMPLE_PASS, /* type */
"ealias", /* name */
OPTGROUP_NONE, /* optinfo_flags */
TV_NONE, /* tv_id */
( PROP_cfg | PROP_ssa ), /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_rebuild_alias, /* todo_flags_finish */
};
class pass_build_ealias : public gimple_opt_pass
{
public:
pass_build_ealias (gcc::context *ctxt)
: gimple_opt_pass (pass_data_build_ealias, ctxt)
{}
/* opt_pass methods: */
bool gate (function *) final override { return flag_tree_pta; }
}; // class pass_build_ealias
} // anon namespace
gimple_opt_pass *
make_pass_build_ealias (gcc::context *ctxt)
{
return new pass_build_ealias (ctxt);
}
/* IPA PTA solutions for ESCAPED. */
struct pt_solution ipa_escaped_pt
= { true, false, false, false, false,
false, false, false, false, false, NULL };
/* Associate node with varinfo DATA. Worker for
cgraph_for_symbol_thunks_and_aliases. */
static bool
associate_varinfo_to_alias (struct cgraph_node *node, void *data)
{
if ((node->alias
|| (node->thunk
&& ! node->inlined_to))
&& node->analyzed
&& !node->ifunc_resolver)
insert_vi_for_tree (node->decl, (varinfo_t)data);
return false;
}
/* Dump varinfo VI to FILE. */
static void
dump_varinfo (FILE *file, varinfo_t vi)
{
if (vi == NULL)
return;
fprintf (file, "%u: %s\n", vi->id, vi->name);
const char *sep = " ";
if (vi->is_artificial_var)
fprintf (file, "%sartificial", sep);
if (vi->is_special_var)
fprintf (file, "%sspecial", sep);
if (vi->is_unknown_size_var)
fprintf (file, "%sunknown-size", sep);
if (vi->is_full_var)
fprintf (file, "%sfull", sep);
if (vi->is_heap_var)
fprintf (file, "%sheap", sep);
if (vi->may_have_pointers)
fprintf (file, "%smay-have-pointers", sep);
if (vi->only_restrict_pointers)
fprintf (file, "%sonly-restrict-pointers", sep);
if (vi->is_restrict_var)
fprintf (file, "%sis-restrict-var", sep);
if (vi->is_global_var)
fprintf (file, "%sglobal", sep);
if (vi->is_ipa_escape_point)
fprintf (file, "%sipa-escape-point", sep);
if (vi->is_fn_info)
fprintf (file, "%sfn-info", sep);
if (vi->ruid)
fprintf (file, "%srestrict-uid:%u", sep, vi->ruid);
if (vi->next)
fprintf (file, "%snext:%u", sep, vi->next);
if (vi->head != vi->id)
fprintf (file, "%shead:%u", sep, vi->head);
if (vi->offset)
fprintf (file, "%soffset:" HOST_WIDE_INT_PRINT_DEC, sep, vi->offset);
if (vi->size != ~(unsigned HOST_WIDE_INT)0)
fprintf (file, "%ssize:" HOST_WIDE_INT_PRINT_DEC, sep, vi->size);
if (vi->fullsize != ~(unsigned HOST_WIDE_INT)0
&& vi->fullsize != vi->size)
fprintf (file, "%sfullsize:" HOST_WIDE_INT_PRINT_DEC, sep,
vi->fullsize);
fprintf (file, "\n");
if (vi->solution && !bitmap_empty_p (vi->solution))
{
bitmap_iterator bi;
unsigned i;
fprintf (file, " solution: {");
EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
fprintf (file, " %u", i);
fprintf (file, " }\n");
}
if (vi->oldsolution && !bitmap_empty_p (vi->oldsolution)
&& !bitmap_equal_p (vi->solution, vi->oldsolution))
{
bitmap_iterator bi;
unsigned i;
fprintf (file, " oldsolution: {");
EXECUTE_IF_SET_IN_BITMAP (vi->oldsolution, 0, i, bi)
fprintf (file, " %u", i);
fprintf (file, " }\n");
}
}
/* Dump varinfo VI to stderr. */
DEBUG_FUNCTION void
debug_varinfo (varinfo_t vi)
{
dump_varinfo (stderr, vi);
}
/* Dump varmap to FILE. */
static void
dump_varmap (FILE *file)
{
if (varmap.length () == 0)
return;
fprintf (file, "variables:\n");
for (unsigned int i = 0; i < varmap.length (); ++i)
{
varinfo_t vi = get_varinfo (i);
dump_varinfo (file, vi);
}
fprintf (file, "\n");
}
/* Dump varmap to stderr. */
DEBUG_FUNCTION void
debug_varmap (void)
{
dump_varmap (stderr);
}
/* Compute whether node is refered to non-locally. Worker for
cgraph_for_symbol_thunks_and_aliases. */
static bool
refered_from_nonlocal_fn (struct cgraph_node *node, void *data)
{
bool *nonlocal_p = (bool *)data;
*nonlocal_p |= (node->used_from_other_partition
|| DECL_EXTERNAL (node->decl)
|| TREE_PUBLIC (node->decl)
|| node->force_output
|| lookup_attribute ("noipa", DECL_ATTRIBUTES (node->decl)));
return false;
}
/* Same for varpool nodes. */
static bool
refered_from_nonlocal_var (struct varpool_node *node, void *data)
{
bool *nonlocal_p = (bool *)data;
*nonlocal_p |= (node->used_from_other_partition
|| DECL_EXTERNAL (node->decl)
|| TREE_PUBLIC (node->decl)
|| node->force_output);
return false;
}
/* Execute the driver for IPA PTA. */
static unsigned int
ipa_pta_execute (void)
{
struct cgraph_node *node;
varpool_node *var;
unsigned int from = 0;
in_ipa_mode = 1;
init_alias_vars ();
if (dump_file && (dump_flags & TDF_DETAILS))
{
symtab->dump (dump_file);
fprintf (dump_file, "\n");
}
if (dump_file)
{
fprintf (dump_file, "Generating generic constraints\n\n");
dump_constraints (dump_file, from);
fprintf (dump_file, "\n");
from = constraints.length ();
}
/* Build the constraints. */
FOR_EACH_DEFINED_FUNCTION (node)
{
varinfo_t vi;
/* Nodes without a body in this partition are not interesting.
Especially do not visit clones at this point for now - we
get duplicate decls there for inline clones at least. */
if (!node->has_gimple_body_p ()
|| node->in_other_partition
|| node->inlined_to)
continue;
node->get_body ();
gcc_assert (!node->clone_of);
/* For externally visible or attribute used annotated functions use
local constraints for their arguments.
For local functions we see all callers and thus do not need initial
constraints for parameters. */
bool nonlocal_p = (node->used_from_other_partition
|| DECL_EXTERNAL (node->decl)
|| TREE_PUBLIC (node->decl)
|| node->force_output
|| lookup_attribute ("noipa",
DECL_ATTRIBUTES (node->decl)));
node->call_for_symbol_thunks_and_aliases (refered_from_nonlocal_fn,
&nonlocal_p, true);
vi = create_function_info_for (node->decl,
alias_get_name (node->decl), false,
nonlocal_p);
if (dump_file
&& from != constraints.length ())
{
fprintf (dump_file,
"Generating initial constraints for %s",
node->dump_name ());
if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
fprintf (dump_file, " (%s)",
IDENTIFIER_POINTER
(DECL_ASSEMBLER_NAME (node->decl)));
fprintf (dump_file, "\n\n");
dump_constraints (dump_file, from);
fprintf (dump_file, "\n");
from = constraints.length ();
}
node->call_for_symbol_thunks_and_aliases
(associate_varinfo_to_alias, vi, true);
}
/* Create constraints for global variables and their initializers. */
FOR_EACH_VARIABLE (var)
{
if (var->alias && var->analyzed)
continue;
varinfo_t vi = get_vi_for_tree (var->decl);
/* For the purpose of IPA PTA unit-local globals are not
escape points. */
bool nonlocal_p = (DECL_EXTERNAL (var->decl)
|| TREE_PUBLIC (var->decl)
|| var->used_from_other_partition
|| var->force_output);
var->call_for_symbol_and_aliases (refered_from_nonlocal_var,
&nonlocal_p, true);
if (nonlocal_p)
vi->is_ipa_escape_point = true;
}
if (dump_file
&& from != constraints.length ())
{
fprintf (dump_file,
"Generating constraints for global initializers\n\n");
dump_constraints (dump_file, from);
fprintf (dump_file, "\n");
from = constraints.length ();
}
FOR_EACH_DEFINED_FUNCTION (node)
{
struct function *func;
basic_block bb;
/* Nodes without a body in this partition are not interesting. */
if (!node->has_gimple_body_p ()
|| node->in_other_partition
|| node->clone_of)
continue;
if (dump_file)
{
fprintf (dump_file,
"Generating constraints for %s", node->dump_name ());
if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
fprintf (dump_file, " (%s)",
IDENTIFIER_POINTER
(DECL_ASSEMBLER_NAME (node->decl)));
fprintf (dump_file, "\n");
}
func = DECL_STRUCT_FUNCTION (node->decl);
gcc_assert (cfun == NULL);
/* Build constriants for the function body. */
FOR_EACH_BB_FN (bb, func)
{
for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
gsi_next (&gsi))
{
gphi *phi = gsi.phi ();
if (! virtual_operand_p (gimple_phi_result (phi)))
find_func_aliases (func, phi);
}
for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);
gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
find_func_aliases (func, stmt);
find_func_clobbers (func, stmt);
}
}
if (dump_file)
{
fprintf (dump_file, "\n");
dump_constraints (dump_file, from);
fprintf (dump_file, "\n");
from = constraints.length ();
}
}
/* From the constraints compute the points-to sets. */
solve_constraints ();
if (dump_file)
dump_sa_points_to_info (dump_file);
/* Now post-process solutions to handle locals from different
runtime instantiations coming in through recursive invocations. */
unsigned shadow_var_cnt = 0;
for (unsigned i = 1; i < varmap.length (); ++i)
{
varinfo_t fi = get_varinfo (i);
if (fi->is_fn_info
&& fi->decl)
/* Automatic variables pointed to by their containing functions
parameters need this treatment. */
for (varinfo_t ai = first_vi_for_offset (fi, fi_parm_base);
ai; ai = vi_next (ai))
{
varinfo_t vi = get_varinfo (find (ai->id));
bitmap_iterator bi;
unsigned j;
EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, j, bi)
{
varinfo_t pt = get_varinfo (j);
if (pt->shadow_var_uid == 0
&& pt->decl
&& auto_var_in_fn_p (pt->decl, fi->decl))
{
pt->shadow_var_uid = allocate_decl_uid ();
shadow_var_cnt++;
}
}
}
/* As well as global variables which are another way of passing
arguments to recursive invocations. */
else if (fi->is_global_var)
{
for (varinfo_t ai = fi; ai; ai = vi_next (ai))
{
varinfo_t vi = get_varinfo (find (ai->id));
bitmap_iterator bi;
unsigned j;
EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, j, bi)
{
varinfo_t pt = get_varinfo (j);
if (pt->shadow_var_uid == 0
&& pt->decl
&& auto_var_p (pt->decl))
{
pt->shadow_var_uid = allocate_decl_uid ();
shadow_var_cnt++;
}
}
}
}
}
if (shadow_var_cnt && dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Allocated %u shadow variables for locals "
"maybe leaking into recursive invocations of their containing "
"functions\n", shadow_var_cnt);
/* Compute the global points-to sets for ESCAPED.
??? Note that the computed escape set is not correct
for the whole unit as we fail to consider graph edges to
externally visible functions. */
ipa_escaped_pt = find_what_var_points_to (NULL, get_varinfo (escaped_id));
/* Make sure the ESCAPED solution (which is used as placeholder in
other solutions) does not reference itself. This simplifies
points-to solution queries. */
ipa_escaped_pt.ipa_escaped = 0;
/* Assign the points-to sets to the SSA names in the unit. */
FOR_EACH_DEFINED_FUNCTION (node)
{
tree ptr;
struct function *fn;
unsigned i;
basic_block bb;
/* Nodes without a body in this partition are not interesting. */
if (!node->has_gimple_body_p ()
|| node->in_other_partition
|| node->clone_of)
continue;
fn = DECL_STRUCT_FUNCTION (node->decl);
/* Compute the points-to sets for pointer SSA_NAMEs. */
FOR_EACH_VEC_ELT (*fn->gimple_df->ssa_names, i, ptr)
{
if (ptr
&& POINTER_TYPE_P (TREE_TYPE (ptr)))
find_what_p_points_to (node->decl, ptr);
}
/* Compute the call-use and call-clobber sets for indirect calls
and calls to external functions. */
FOR_EACH_BB_FN (bb, fn)
{
gimple_stmt_iterator gsi;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gcall *stmt;
struct pt_solution *pt;
varinfo_t vi, fi;
tree decl;
stmt = dyn_cast <gcall *> (gsi_stmt (gsi));
if (!stmt)
continue;
/* Handle direct calls to functions with body. */
decl = gimple_call_fndecl (stmt);
{
tree called_decl = NULL_TREE;
if (gimple_call_builtin_p (stmt, BUILT_IN_GOMP_PARALLEL))
called_decl = TREE_OPERAND (gimple_call_arg (stmt, 0), 0);
else if (gimple_call_builtin_p (stmt, BUILT_IN_GOACC_PARALLEL))
called_decl = TREE_OPERAND (gimple_call_arg (stmt, 1), 0);
if (called_decl != NULL_TREE
&& !fndecl_maybe_in_other_partition (called_decl))
decl = called_decl;
}
if (decl
&& (fi = lookup_vi_for_tree (decl))
&& fi->is_fn_info)
{
*gimple_call_clobber_set (stmt)
= find_what_var_points_to
(node->decl, first_vi_for_offset (fi, fi_clobbers));
*gimple_call_use_set (stmt)
= find_what_var_points_to
(node->decl, first_vi_for_offset (fi, fi_uses));
}
/* Handle direct calls to external functions. */
else if (decl && (!fi || fi->decl))
{
pt = gimple_call_use_set (stmt);
if (gimple_call_flags (stmt) & ECF_CONST)
memset (pt, 0, sizeof (struct pt_solution));
else if ((vi = lookup_call_use_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (node->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly used by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
pt->nonlocal = 1;
pt->ipa_escaped = 1;
}
else
{
/* If there is nothing special about this call then
we have made everything that is used also escape. */
*pt = ipa_escaped_pt;
pt->nonlocal = 1;
}
pt = gimple_call_clobber_set (stmt);
if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
memset (pt, 0, sizeof (struct pt_solution));
else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (node->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly clobbered by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
pt->nonlocal = 1;
pt->ipa_escaped = 1;
}
else
{
/* If there is nothing special about this call then
we have made everything that is used also escape. */
*pt = ipa_escaped_pt;
pt->nonlocal = 1;
}
}
/* Handle indirect calls. */
else if ((fi = get_fi_for_callee (stmt)))
{
/* We need to accumulate all clobbers/uses of all possible
callees. */
fi = get_varinfo (find (fi->id));
/* If we cannot constrain the set of functions we'll end up
calling we end up using/clobbering everything. */
if (bitmap_bit_p (fi->solution, anything_id)
|| bitmap_bit_p (fi->solution, nonlocal_id)
|| bitmap_bit_p (fi->solution, escaped_id))
{
pt_solution_reset (gimple_call_clobber_set (stmt));
pt_solution_reset (gimple_call_use_set (stmt));
}
else
{
bitmap_iterator bi;
unsigned i;
struct pt_solution *uses, *clobbers;
uses = gimple_call_use_set (stmt);
clobbers = gimple_call_clobber_set (stmt);
memset (uses, 0, sizeof (struct pt_solution));
memset (clobbers, 0, sizeof (struct pt_solution));
EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
{
struct pt_solution sol;
vi = get_varinfo (i);
if (!vi->is_fn_info)
{
/* ??? We could be more precise here? */
uses->nonlocal = 1;
uses->ipa_escaped = 1;
clobbers->nonlocal = 1;
clobbers->ipa_escaped = 1;
continue;
}
if (!uses->anything)
{
sol = find_what_var_points_to
(node->decl,
first_vi_for_offset (vi, fi_uses));
pt_solution_ior_into (uses, &sol);
}
if (!clobbers->anything)
{
sol = find_what_var_points_to
(node->decl,
first_vi_for_offset (vi, fi_clobbers));
pt_solution_ior_into (clobbers, &sol);
}
}
}
}
else
gcc_unreachable ();
}
}
fn->gimple_df->ipa_pta = true;
/* We have to re-set the final-solution cache after each function
because what is a "global" is dependent on function context. */
final_solutions->empty ();
obstack_free (&final_solutions_obstack, NULL);
gcc_obstack_init (&final_solutions_obstack);
}
delete_points_to_sets ();
in_ipa_mode = 0;
return 0;
}
namespace {
const pass_data pass_data_ipa_pta =
{
SIMPLE_IPA_PASS, /* type */
"pta", /* name */
OPTGROUP_NONE, /* optinfo_flags */
TV_IPA_PTA, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
0, /* todo_flags_finish */
};
class pass_ipa_pta : public simple_ipa_opt_pass
{
public:
pass_ipa_pta (gcc::context *ctxt)
: simple_ipa_opt_pass (pass_data_ipa_pta, ctxt)
{}
/* opt_pass methods: */
bool gate (function *) final override
{
return (optimize
&& flag_ipa_pta
/* Don't bother doing anything if the program has errors. */
&& !seen_error ());
}
opt_pass * clone () final override { return new pass_ipa_pta (m_ctxt); }
unsigned int execute (function *) final override
{
return ipa_pta_execute ();
}
}; // class pass_ipa_pta
} // anon namespace
simple_ipa_opt_pass *
make_pass_ipa_pta (gcc::context *ctxt)
{
return new pass_ipa_pta (ctxt);
}