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/* Implements exception handling.
Copyright (C) 1989-2021 Free Software Foundation, Inc.
Contributed by Mike Stump <mrs@cygnus.com>.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, 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/>. */
/* An exception is an event that can be "thrown" from within a
function. This event can then be "caught" by the callers of
the function.
The representation of exceptions changes several times during
the compilation process:
In the beginning, in the front end, we have the GENERIC trees
TRY_CATCH_EXPR, TRY_FINALLY_EXPR, EH_ELSE_EXPR, WITH_CLEANUP_EXPR,
CLEANUP_POINT_EXPR, CATCH_EXPR, and EH_FILTER_EXPR.
During initial gimplification (gimplify.c) these are lowered to the
GIMPLE_TRY, GIMPLE_CATCH, GIMPLE_EH_ELSE, and GIMPLE_EH_FILTER
nodes. The WITH_CLEANUP_EXPR and CLEANUP_POINT_EXPR nodes are
converted into GIMPLE_TRY_FINALLY nodes; the others are a more
direct 1-1 conversion.
During pass_lower_eh (tree-eh.c) we record the nested structure
of the TRY nodes in EH_REGION nodes in CFUN->EH->REGION_TREE.
We expand the eh_protect_cleanup_actions langhook into MUST_NOT_THROW
regions at this time. We can then flatten the statements within
the TRY nodes to straight-line code. Statements that had been within
TRY nodes that can throw are recorded within CFUN->EH->THROW_STMT_TABLE,
so that we may remember what action is supposed to be taken if
a given statement does throw. During this lowering process,
we create an EH_LANDING_PAD node for each EH_REGION that has
some code within the function that needs to be executed if a
throw does happen. We also create RESX statements that are
used to transfer control from an inner EH_REGION to an outer
EH_REGION. We also create EH_DISPATCH statements as placeholders
for a runtime type comparison that should be made in order to
select the action to perform among different CATCH and EH_FILTER
regions.
During pass_lower_eh_dispatch (tree-eh.c), which is run after
all inlining is complete, we are able to run assign_filter_values,
which allows us to map the set of types manipulated by all of the
CATCH and EH_FILTER regions to a set of integers. This set of integers
will be how the exception runtime communicates with the code generated
within the function. We then expand the GIMPLE_EH_DISPATCH statements
to a switch or conditional branches that use the argument provided by
the runtime (__builtin_eh_filter) and the set of integers we computed
in assign_filter_values.
During pass_lower_resx (tree-eh.c), which is run near the end
of optimization, we expand RESX statements. If the eh region
that is outer to the RESX statement is a MUST_NOT_THROW, then
the RESX expands to some form of abort statement. If the eh
region that is outer to the RESX statement is within the current
function, then the RESX expands to a bookkeeping call
(__builtin_eh_copy_values) and a goto. Otherwise, the next
handler for the exception must be within a function somewhere
up the call chain, so we call back into the exception runtime
(__builtin_unwind_resume).
During pass_expand (cfgexpand.c), we generate REG_EH_REGION notes
that create an rtl to eh_region mapping that corresponds to the
gimple to eh_region mapping that had been recorded in the
THROW_STMT_TABLE.
Then, via finish_eh_generation, we generate the real landing pads
to which the runtime will actually transfer control. These new
landing pads perform whatever bookkeeping is needed by the target
backend in order to resume execution within the current function.
Each of these new landing pads falls through into the post_landing_pad
label which had been used within the CFG up to this point. All
exception edges within the CFG are redirected to the new landing pads.
If the target uses setjmp to implement exceptions, the various extra
calls into the runtime to register and unregister the current stack
frame are emitted at this time.
During pass_convert_to_eh_region_ranges (except.c), we transform
the REG_EH_REGION notes attached to individual insns into
non-overlapping ranges of insns bounded by NOTE_INSN_EH_REGION_BEG
and NOTE_INSN_EH_REGION_END. Each insn within such ranges has the
same associated action within the exception region tree, meaning
that (1) the exception is caught by the same landing pad within the
current function, (2) the exception is blocked by the runtime with
a MUST_NOT_THROW region, or (3) the exception is not handled at all
within the current function.
Finally, during assembly generation, we call
output_function_exception_table (except.c) to emit the tables with
which the exception runtime can determine if a given stack frame
handles a given exception, and if so what filter value to provide
to the function when the non-local control transfer is effected.
If the target uses dwarf2 unwinding to implement exceptions, then
output_call_frame_info (dwarf2out.c) emits the required unwind data. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "target.h"
#include "rtl.h"
#include "tree.h"
#include "cfghooks.h"
#include "tree-pass.h"
#include "memmodel.h"
#include "tm_p.h"
#include "stringpool.h"
#include "expmed.h"
#include "optabs.h"
#include "emit-rtl.h"
#include "cgraph.h"
#include "diagnostic.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "explow.h"
#include "stmt.h"
#include "expr.h"
#include "calls.h"
#include "libfuncs.h"
#include "except.h"
#include "output.h"
#include "dwarf2asm.h"
#include "dwarf2.h"
#include "common/common-target.h"
#include "langhooks.h"
#include "cfgrtl.h"
#include "tree-pretty-print.h"
#include "cfgloop.h"
#include "builtins.h"
#include "tree-hash-traits.h"
#include "flags.h"
static GTY(()) int call_site_base;
static GTY(()) hash_map<tree_hash, tree> *type_to_runtime_map;
static GTY(()) tree setjmp_fn;
/* Describe the SjLj_Function_Context structure. */
static GTY(()) tree sjlj_fc_type_node;
static int sjlj_fc_call_site_ofs;
static int sjlj_fc_data_ofs;
static int sjlj_fc_personality_ofs;
static int sjlj_fc_lsda_ofs;
static int sjlj_fc_jbuf_ofs;
struct GTY(()) call_site_record_d
{
rtx landing_pad;
int action;
};
/* In the following structure and associated functions,
we represent entries in the action table as 1-based indices.
Special cases are:
0: null action record, non-null landing pad; implies cleanups
-1: null action record, null landing pad; implies no action
-2: no call-site entry; implies must_not_throw
-3: we have yet to process outer regions
Further, no special cases apply to the "next" field of the record.
For next, 0 means end of list. */
struct action_record
{
int offset;
int filter;
int next;
};
/* Hashtable helpers. */
struct action_record_hasher : free_ptr_hash <action_record>
{
static inline hashval_t hash (const action_record *);
static inline bool equal (const action_record *, const action_record *);
};
inline hashval_t
action_record_hasher::hash (const action_record *entry)
{
return entry->next * 1009 + entry->filter;
}
inline bool
action_record_hasher::equal (const action_record *entry,
const action_record *data)
{
return entry->filter == data->filter && entry->next == data->next;
}
typedef hash_table<action_record_hasher> action_hash_type;
static bool get_eh_region_and_lp_from_rtx (const_rtx, eh_region *,
eh_landing_pad *);
static void dw2_build_landing_pads (void);
static int collect_one_action_chain (action_hash_type *, eh_region);
static int add_call_site (rtx, int, int);
static void push_uleb128 (vec<uchar, va_gc> **, unsigned int);
static void push_sleb128 (vec<uchar, va_gc> **, int);
static int dw2_size_of_call_site_table (int);
static int sjlj_size_of_call_site_table (void);
static void dw2_output_call_site_table (int, int);
static void sjlj_output_call_site_table (void);
void
init_eh (void)
{
if (! flag_exceptions)
return;
type_to_runtime_map = hash_map<tree_hash, tree>::create_ggc (31);
/* Create the SjLj_Function_Context structure. This should match
the definition in unwind-sjlj.c. */
if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ)
{
tree f_jbuf, f_per, f_lsda, f_prev, f_cs, f_data, tmp;
sjlj_fc_type_node = lang_hooks.types.make_type (RECORD_TYPE);
f_prev = build_decl (BUILTINS_LOCATION,
FIELD_DECL, get_identifier ("__prev"),
build_pointer_type (sjlj_fc_type_node));
DECL_FIELD_CONTEXT (f_prev) = sjlj_fc_type_node;
f_cs = build_decl (BUILTINS_LOCATION,
FIELD_DECL, get_identifier ("__call_site"),
integer_type_node);
DECL_FIELD_CONTEXT (f_cs) = sjlj_fc_type_node;
tmp = build_index_type (size_int (4 - 1));
tmp = build_array_type (lang_hooks.types.type_for_mode
(targetm.unwind_word_mode (), 1),
tmp);
f_data = build_decl (BUILTINS_LOCATION,
FIELD_DECL, get_identifier ("__data"), tmp);
DECL_FIELD_CONTEXT (f_data) = sjlj_fc_type_node;
f_per = build_decl (BUILTINS_LOCATION,
FIELD_DECL, get_identifier ("__personality"),
ptr_type_node);
DECL_FIELD_CONTEXT (f_per) = sjlj_fc_type_node;
f_lsda = build_decl (BUILTINS_LOCATION,
FIELD_DECL, get_identifier ("__lsda"),
ptr_type_node);
DECL_FIELD_CONTEXT (f_lsda) = sjlj_fc_type_node;
#ifdef DONT_USE_BUILTIN_SETJMP
#ifdef JMP_BUF_SIZE
tmp = size_int (JMP_BUF_SIZE - 1);
#else
/* Should be large enough for most systems, if it is not,
JMP_BUF_SIZE should be defined with the proper value. It will
also tend to be larger than necessary for most systems, a more
optimal port will define JMP_BUF_SIZE. */
tmp = size_int (FIRST_PSEUDO_REGISTER + 2 - 1);
#endif
#else
/* Compute a minimally sized jump buffer. We need room to store at
least 3 pointers - stack pointer, frame pointer and return address.
Plus for some targets we need room for an extra pointer - in the
case of MIPS this is the global pointer. This makes a total of four
pointers, but to be safe we actually allocate room for 5.
If pointers are smaller than words then we allocate enough room for
5 words, just in case the backend needs this much room. For more
discussion on this issue see:
http://gcc.gnu.org/ml/gcc-patches/2014-05/msg00313.html. */
if (POINTER_SIZE > BITS_PER_WORD)
tmp = size_int (5 - 1);
else
tmp = size_int ((5 * BITS_PER_WORD / POINTER_SIZE) - 1);
#endif
tmp = build_index_type (tmp);
tmp = build_array_type (ptr_type_node, tmp);
f_jbuf = build_decl (BUILTINS_LOCATION,
FIELD_DECL, get_identifier ("__jbuf"), tmp);
#ifdef DONT_USE_BUILTIN_SETJMP
/* We don't know what the alignment requirements of the
runtime's jmp_buf has. Overestimate. */
SET_DECL_ALIGN (f_jbuf, BIGGEST_ALIGNMENT);
DECL_USER_ALIGN (f_jbuf) = 1;
#endif
DECL_FIELD_CONTEXT (f_jbuf) = sjlj_fc_type_node;
TYPE_FIELDS (sjlj_fc_type_node) = f_prev;
TREE_CHAIN (f_prev) = f_cs;
TREE_CHAIN (f_cs) = f_data;
TREE_CHAIN (f_data) = f_per;
TREE_CHAIN (f_per) = f_lsda;
TREE_CHAIN (f_lsda) = f_jbuf;
layout_type (sjlj_fc_type_node);
/* Cache the interesting field offsets so that we have
easy access from rtl. */
sjlj_fc_call_site_ofs
= (tree_to_uhwi (DECL_FIELD_OFFSET (f_cs))
+ tree_to_uhwi (DECL_FIELD_BIT_OFFSET (f_cs)) / BITS_PER_UNIT);
sjlj_fc_data_ofs
= (tree_to_uhwi (DECL_FIELD_OFFSET (f_data))
+ tree_to_uhwi (DECL_FIELD_BIT_OFFSET (f_data)) / BITS_PER_UNIT);
sjlj_fc_personality_ofs
= (tree_to_uhwi (DECL_FIELD_OFFSET (f_per))
+ tree_to_uhwi (DECL_FIELD_BIT_OFFSET (f_per)) / BITS_PER_UNIT);
sjlj_fc_lsda_ofs
= (tree_to_uhwi (DECL_FIELD_OFFSET (f_lsda))
+ tree_to_uhwi (DECL_FIELD_BIT_OFFSET (f_lsda)) / BITS_PER_UNIT);
sjlj_fc_jbuf_ofs
= (tree_to_uhwi (DECL_FIELD_OFFSET (f_jbuf))
+ tree_to_uhwi (DECL_FIELD_BIT_OFFSET (f_jbuf)) / BITS_PER_UNIT);
#ifdef DONT_USE_BUILTIN_SETJMP
tmp = build_function_type_list (integer_type_node, TREE_TYPE (f_jbuf),
NULL);
setjmp_fn = build_decl (BUILTINS_LOCATION, FUNCTION_DECL,
get_identifier ("setjmp"), tmp);
TREE_PUBLIC (setjmp_fn) = 1;
DECL_EXTERNAL (setjmp_fn) = 1;
DECL_ASSEMBLER_NAME (setjmp_fn);
#endif
}
}
void
init_eh_for_function (void)
{
cfun->eh = ggc_cleared_alloc<eh_status> ();
/* Make sure zero'th entries are used. */
vec_safe_push (cfun->eh->region_array, (eh_region)0);
vec_safe_push (cfun->eh->lp_array, (eh_landing_pad)0);
}
/* Routines to generate the exception tree somewhat directly.
These are used from tree-eh.c when processing exception related
nodes during tree optimization. */
static eh_region
gen_eh_region (enum eh_region_type type, eh_region outer)
{
eh_region new_eh;
/* Insert a new blank region as a leaf in the tree. */
new_eh = ggc_cleared_alloc<eh_region_d> ();
new_eh->type = type;
new_eh->outer = outer;
if (outer)
{
new_eh->next_peer = outer->inner;
outer->inner = new_eh;
}
else
{
new_eh->next_peer = cfun->eh->region_tree;
cfun->eh->region_tree = new_eh;
}
new_eh->index = vec_safe_length (cfun->eh->region_array);
vec_safe_push (cfun->eh->region_array, new_eh);
/* Copy the language's notion of whether to use __cxa_end_cleanup. */
if (targetm.arm_eabi_unwinder && lang_hooks.eh_use_cxa_end_cleanup)
new_eh->use_cxa_end_cleanup = true;
return new_eh;
}
eh_region
gen_eh_region_cleanup (eh_region outer)
{
return gen_eh_region (ERT_CLEANUP, outer);
}
eh_region
gen_eh_region_try (eh_region outer)
{
return gen_eh_region (ERT_TRY, outer);
}
eh_catch
gen_eh_region_catch (eh_region t, tree type_or_list)
{
eh_catch c, l;
tree type_list, type_node;
gcc_assert (t->type == ERT_TRY);
/* Ensure to always end up with a type list to normalize further
processing, then register each type against the runtime types map. */
type_list = type_or_list;
if (type_or_list)
{
if (TREE_CODE (type_or_list) != TREE_LIST)
type_list = tree_cons (NULL_TREE, type_or_list, NULL_TREE);
type_node = type_list;
for (; type_node; type_node = TREE_CHAIN (type_node))
add_type_for_runtime (TREE_VALUE (type_node));
}
c = ggc_cleared_alloc<eh_catch_d> ();
c->type_list = type_list;
l = t->u.eh_try.last_catch;
c->prev_catch = l;
if (l)
l->next_catch = c;
else
t->u.eh_try.first_catch = c;
t->u.eh_try.last_catch = c;
return c;
}
eh_region
gen_eh_region_allowed (eh_region outer, tree allowed)
{
eh_region region = gen_eh_region (ERT_ALLOWED_EXCEPTIONS, outer);
region->u.allowed.type_list = allowed;
for (; allowed ; allowed = TREE_CHAIN (allowed))
add_type_for_runtime (TREE_VALUE (allowed));
return region;
}
eh_region
gen_eh_region_must_not_throw (eh_region outer)
{
return gen_eh_region (ERT_MUST_NOT_THROW, outer);
}
eh_landing_pad
gen_eh_landing_pad (eh_region region)
{
eh_landing_pad lp = ggc_cleared_alloc<eh_landing_pad_d> ();
lp->next_lp = region->landing_pads;
lp->region = region;
lp->index = vec_safe_length (cfun->eh->lp_array);
region->landing_pads = lp;
vec_safe_push (cfun->eh->lp_array, lp);
return lp;
}
eh_region
get_eh_region_from_number_fn (struct function *ifun, int i)
{
return (*ifun->eh->region_array)[i];
}
eh_region
get_eh_region_from_number (int i)
{
return get_eh_region_from_number_fn (cfun, i);
}
eh_landing_pad
get_eh_landing_pad_from_number_fn (struct function *ifun, int i)
{
return (*ifun->eh->lp_array)[i];
}
eh_landing_pad
get_eh_landing_pad_from_number (int i)
{
return get_eh_landing_pad_from_number_fn (cfun, i);
}
eh_region
get_eh_region_from_lp_number_fn (struct function *ifun, int i)
{
if (i < 0)
return (*ifun->eh->region_array)[-i];
else if (i == 0)
return NULL;
else
{
eh_landing_pad lp;
lp = (*ifun->eh->lp_array)[i];
return lp->region;
}
}
eh_region
get_eh_region_from_lp_number (int i)
{
return get_eh_region_from_lp_number_fn (cfun, i);
}
/* Returns true if the current function has exception handling regions. */
bool
current_function_has_exception_handlers (void)
{
return cfun->eh->region_tree != NULL;
}
/* A subroutine of duplicate_eh_regions. Copy the eh_region tree at OLD.
Root it at OUTER, and apply LP_OFFSET to the lp numbers. */
struct duplicate_eh_regions_data
{
duplicate_eh_regions_map label_map;
void *label_map_data;
hash_map<void *, void *> *eh_map;
};
static void
duplicate_eh_regions_1 (struct duplicate_eh_regions_data *data,
eh_region old_r, eh_region outer)
{
eh_landing_pad old_lp, new_lp;
eh_region new_r;
new_r = gen_eh_region (old_r->type, outer);
gcc_assert (!data->eh_map->put (old_r, new_r));
switch (old_r->type)
{
case ERT_CLEANUP:
break;
case ERT_TRY:
{
eh_catch oc, nc;
for (oc = old_r->u.eh_try.first_catch; oc ; oc = oc->next_catch)
{
/* We should be doing all our region duplication before and
during inlining, which is before filter lists are created. */
gcc_assert (oc->filter_list == NULL);
nc = gen_eh_region_catch (new_r, oc->type_list);
nc->label = data->label_map (oc->label, data->label_map_data);
}
}
break;
case ERT_ALLOWED_EXCEPTIONS:
new_r->u.allowed.type_list = old_r->u.allowed.type_list;
if (old_r->u.allowed.label)
new_r->u.allowed.label
= data->label_map (old_r->u.allowed.label, data->label_map_data);
else
new_r->u.allowed.label = NULL_TREE;
break;
case ERT_MUST_NOT_THROW:
new_r->u.must_not_throw.failure_loc =
LOCATION_LOCUS (old_r->u.must_not_throw.failure_loc);
new_r->u.must_not_throw.failure_decl =
old_r->u.must_not_throw.failure_decl;
break;
}
for (old_lp = old_r->landing_pads; old_lp ; old_lp = old_lp->next_lp)
{
/* Don't bother copying unused landing pads. */
if (old_lp->post_landing_pad == NULL)
continue;
new_lp = gen_eh_landing_pad (new_r);
gcc_assert (!data->eh_map->put (old_lp, new_lp));
new_lp->post_landing_pad
= data->label_map (old_lp->post_landing_pad, data->label_map_data);
EH_LANDING_PAD_NR (new_lp->post_landing_pad) = new_lp->index;
}
/* Make sure to preserve the original use of __cxa_end_cleanup. */
new_r->use_cxa_end_cleanup = old_r->use_cxa_end_cleanup;
for (old_r = old_r->inner; old_r ; old_r = old_r->next_peer)
duplicate_eh_regions_1 (data, old_r, new_r);
}
/* Duplicate the EH regions from IFUN rooted at COPY_REGION into
the current function and root the tree below OUTER_REGION.
The special case of COPY_REGION of NULL means all regions.
Remap labels using MAP/MAP_DATA callback. Return a pointer map
that allows the caller to remap uses of both EH regions and
EH landing pads. */
hash_map<void *, void *> *
duplicate_eh_regions (struct function *ifun,
eh_region copy_region, int outer_lp,
duplicate_eh_regions_map map, void *map_data)
{
struct duplicate_eh_regions_data data;
eh_region outer_region;
if (flag_checking)
verify_eh_tree (ifun);
data.label_map = map;
data.label_map_data = map_data;
data.eh_map = new hash_map<void *, void *>;
outer_region = get_eh_region_from_lp_number_fn (cfun, outer_lp);
/* Copy all the regions in the subtree. */
if (copy_region)
duplicate_eh_regions_1 (&data, copy_region, outer_region);
else
{
eh_region r;
for (r = ifun->eh->region_tree; r ; r = r->next_peer)
duplicate_eh_regions_1 (&data, r, outer_region);
}
if (flag_checking)
verify_eh_tree (cfun);
return data.eh_map;
}
/* Return the region that is outer to both REGION_A and REGION_B in IFUN. */
eh_region
eh_region_outermost (struct function *ifun, eh_region region_a,
eh_region region_b)
{
gcc_assert (ifun->eh->region_array);
gcc_assert (ifun->eh->region_tree);
auto_sbitmap b_outer (ifun->eh->region_array->length ());
bitmap_clear (b_outer);
do
{
bitmap_set_bit (b_outer, region_b->index);
region_b = region_b->outer;
}
while (region_b);
do
{
if (bitmap_bit_p (b_outer, region_a->index))
break;
region_a = region_a->outer;
}
while (region_a);
return region_a;
}
void
add_type_for_runtime (tree type)
{
/* If TYPE is NOP_EXPR, it means that it already is a runtime type. */
if (TREE_CODE (type) == NOP_EXPR)
return;
bool existed = false;
tree *slot = &type_to_runtime_map->get_or_insert (type, &existed);
if (!existed)
*slot = lang_hooks.eh_runtime_type (type);
}
tree
lookup_type_for_runtime (tree type)
{
/* If TYPE is NOP_EXPR, it means that it already is a runtime type. */
if (TREE_CODE (type) == NOP_EXPR)
return type;
/* We should have always inserted the data earlier. */
return *type_to_runtime_map->get (type);
}
/* Represent an entry in @TTypes for either catch actions
or exception filter actions. */
struct ttypes_filter {
tree t;
int filter;
};
/* Helper for ttypes_filter hashing. */
struct ttypes_filter_hasher : free_ptr_hash <ttypes_filter>
{
typedef tree_node *compare_type;
static inline hashval_t hash (const ttypes_filter *);
static inline bool equal (const ttypes_filter *, const tree_node *);
};
/* Compare ENTRY (a ttypes_filter entry in the hash table) with DATA
(a tree) for a @TTypes type node we are thinking about adding. */
inline bool
ttypes_filter_hasher::equal (const ttypes_filter *entry, const tree_node *data)
{
return entry->t == data;
}
inline hashval_t
ttypes_filter_hasher::hash (const ttypes_filter *entry)
{
return TREE_HASH (entry->t);
}
typedef hash_table<ttypes_filter_hasher> ttypes_hash_type;
/* Helper for ehspec hashing. */
struct ehspec_hasher : free_ptr_hash <ttypes_filter>
{
static inline hashval_t hash (const ttypes_filter *);
static inline bool equal (const ttypes_filter *, const ttypes_filter *);
};
/* Compare ENTRY with DATA (both struct ttypes_filter) for a @TTypes
exception specification list we are thinking about adding. */
/* ??? Currently we use the type lists in the order given. Someone
should put these in some canonical order. */
inline bool
ehspec_hasher::equal (const ttypes_filter *entry, const ttypes_filter *data)
{
return type_list_equal (entry->t, data->t);
}
/* Hash function for exception specification lists. */
inline hashval_t
ehspec_hasher::hash (const ttypes_filter *entry)
{
hashval_t h = 0;
tree list;
for (list = entry->t; list ; list = TREE_CHAIN (list))
h = (h << 5) + (h >> 27) + TREE_HASH (TREE_VALUE (list));
return h;
}
typedef hash_table<ehspec_hasher> ehspec_hash_type;
/* Add TYPE (which may be NULL) to cfun->eh->ttype_data, using TYPES_HASH
to speed up the search. Return the filter value to be used. */
static int
add_ttypes_entry (ttypes_hash_type *ttypes_hash, tree type)
{
struct ttypes_filter **slot, *n;
slot = ttypes_hash->find_slot_with_hash (type, (hashval_t) TREE_HASH (type),
INSERT);
if ((n = *slot) == NULL)
{
/* Filter value is a 1 based table index. */
n = XNEW (struct ttypes_filter);
n->t = type;
n->filter = vec_safe_length (cfun->eh->ttype_data) + 1;
*slot = n;
vec_safe_push (cfun->eh->ttype_data, type);
}
return n->filter;
}
/* Add LIST to cfun->eh->ehspec_data, using EHSPEC_HASH and TYPES_HASH
to speed up the search. Return the filter value to be used. */
static int
add_ehspec_entry (ehspec_hash_type *ehspec_hash, ttypes_hash_type *ttypes_hash,
tree list)
{
struct ttypes_filter **slot, *n;
struct ttypes_filter dummy;
dummy.t = list;
slot = ehspec_hash->find_slot (&dummy, INSERT);
if ((n = *slot) == NULL)
{
int len;
if (targetm.arm_eabi_unwinder)
len = vec_safe_length (cfun->eh->ehspec_data.arm_eabi);
else
len = vec_safe_length (cfun->eh->ehspec_data.other);
/* Filter value is a -1 based byte index into a uleb128 buffer. */
n = XNEW (struct ttypes_filter);
n->t = list;
n->filter = -(len + 1);
*slot = n;
/* Generate a 0 terminated list of filter values. */
for (; list ; list = TREE_CHAIN (list))
{
if (targetm.arm_eabi_unwinder)
vec_safe_push (cfun->eh->ehspec_data.arm_eabi, TREE_VALUE (list));
else
{
/* Look up each type in the list and encode its filter
value as a uleb128. */
push_uleb128 (&cfun->eh->ehspec_data.other,
add_ttypes_entry (ttypes_hash, TREE_VALUE (list)));
}
}
if (targetm.arm_eabi_unwinder)
vec_safe_push (cfun->eh->ehspec_data.arm_eabi, NULL_TREE);
else
vec_safe_push (cfun->eh->ehspec_data.other, (uchar)0);
}
return n->filter;
}
/* Generate the action filter values to be used for CATCH and
ALLOWED_EXCEPTIONS regions. When using dwarf2 exception regions,
we use lots of landing pads, and so every type or list can share
the same filter value, which saves table space. */
void
assign_filter_values (void)
{
int i;
eh_region r;
eh_catch c;
vec_alloc (cfun->eh->ttype_data, 16);
if (targetm.arm_eabi_unwinder)
vec_alloc (cfun->eh->ehspec_data.arm_eabi, 64);
else
vec_alloc (cfun->eh->ehspec_data.other, 64);
ehspec_hash_type ehspec (31);
ttypes_hash_type ttypes (31);
for (i = 1; vec_safe_iterate (cfun->eh->region_array, i, &r); ++i)
{
if (r == NULL)
continue;
switch (r->type)
{
case ERT_TRY:
for (c = r->u.eh_try.first_catch; c ; c = c->next_catch)
{
/* Whatever type_list is (NULL or true list), we build a list
of filters for the region. */
c->filter_list = NULL_TREE;
if (c->type_list != NULL)
{
/* Get a filter value for each of the types caught and store
them in the region's dedicated list. */
tree tp_node = c->type_list;
for ( ; tp_node; tp_node = TREE_CHAIN (tp_node))
{
int flt
= add_ttypes_entry (&ttypes, TREE_VALUE (tp_node));
tree flt_node = build_int_cst (integer_type_node, flt);
c->filter_list
= tree_cons (NULL_TREE, flt_node, c->filter_list);
}
}
else
{
/* Get a filter value for the NULL list also since it
will need an action record anyway. */
int flt = add_ttypes_entry (&ttypes, NULL);
tree flt_node = build_int_cst (integer_type_node, flt);
c->filter_list
= tree_cons (NULL_TREE, flt_node, NULL);
}
}
break;
case ERT_ALLOWED_EXCEPTIONS:
r->u.allowed.filter
= add_ehspec_entry (&ehspec, &ttypes, r->u.allowed.type_list);
break;
default:
break;
}
}
}
/* Emit SEQ into basic block just before INSN (that is assumed to be
first instruction of some existing BB and return the newly
produced block. */
static basic_block
emit_to_new_bb_before (rtx_insn *seq, rtx_insn *insn)
{
rtx_insn *next, *last;
basic_block bb;
edge e;
edge_iterator ei;
/* If there happens to be a fallthru edge (possibly created by cleanup_cfg
call), we don't want it to go into newly created landing pad or other EH
construct. */
for (ei = ei_start (BLOCK_FOR_INSN (insn)->preds); (e = ei_safe_edge (ei)); )
if (e->flags & EDGE_FALLTHRU)
force_nonfallthru (e);
else
ei_next (&ei);
/* Make sure to put the location of INSN or a subsequent instruction on SEQ
to avoid inheriting the location of the previous instruction. */
next = insn;
while (next && !NONDEBUG_INSN_P (next))
next = NEXT_INSN (next);
if (next)
last = emit_insn_before_setloc (seq, insn, INSN_LOCATION (next));
else
last = emit_insn_before (seq, insn);
if (BARRIER_P (last))
last = PREV_INSN (last);
bb = create_basic_block (seq, last, BLOCK_FOR_INSN (insn)->prev_bb);
update_bb_for_insn (bb);
bb->flags |= BB_SUPERBLOCK;
return bb;
}
/* A subroutine of dw2_build_landing_pads, also used for edge splitting
at the rtl level. Emit the code required by the target at a landing
pad for the given region. */
static void
expand_dw2_landing_pad_for_region (eh_region region)
{
if (targetm.have_exception_receiver ())
emit_insn (targetm.gen_exception_receiver ());
else if (targetm.have_nonlocal_goto_receiver ())
emit_insn (targetm.gen_nonlocal_goto_receiver ());
else
{ /* Nothing */ }
if (region->exc_ptr_reg)
emit_move_insn (region->exc_ptr_reg,
gen_rtx_REG (ptr_mode, EH_RETURN_DATA_REGNO (0)));
if (region->filter_reg)
emit_move_insn (region->filter_reg,
gen_rtx_REG (targetm.eh_return_filter_mode (),
EH_RETURN_DATA_REGNO (1)));
}
/* Expand the extra code needed at landing pads for dwarf2 unwinding. */
static void
dw2_build_landing_pads (void)
{
int i;
eh_landing_pad lp;
int e_flags = EDGE_FALLTHRU;
/* If we're going to partition blocks, we need to be able to add
new landing pads later, which means that we need to hold on to
the post-landing-pad block. Prevent it from being merged away.
We'll remove this bit after partitioning. */
if (flag_reorder_blocks_and_partition)
e_flags |= EDGE_PRESERVE;
for (i = 1; vec_safe_iterate (cfun->eh->lp_array, i, &lp); ++i)
{
basic_block bb;
rtx_insn *seq;
if (lp == NULL || lp->post_landing_pad == NULL)
continue;
start_sequence ();
lp->landing_pad = gen_label_rtx ();
emit_label (lp->landing_pad);
LABEL_PRESERVE_P (lp->landing_pad) = 1;
expand_dw2_landing_pad_for_region (lp->region);
seq = get_insns ();
end_sequence ();
bb = emit_to_new_bb_before (seq, label_rtx (lp->post_landing_pad));
bb->count = bb->next_bb->count;
make_single_succ_edge (bb, bb->next_bb, e_flags);
if (current_loops)
{
class loop *loop = bb->next_bb->loop_father;
/* If we created a pre-header block, add the new block to the
outer loop, otherwise to the loop itself. */
if (bb->next_bb == loop->header)
add_bb_to_loop (bb, loop_outer (loop));
else
add_bb_to_loop (bb, loop);
}
}
}
static vec<int> sjlj_lp_call_site_index;
/* Process all active landing pads. Assign each one a compact dispatch
index, and a call-site index. */
static int
sjlj_assign_call_site_values (void)
{
action_hash_type ar_hash (31);
int i, disp_index;
eh_landing_pad lp;
vec_alloc (crtl->eh.action_record_data, 64);
disp_index = 0;
call_site_base = 1;
for (i = 1; vec_safe_iterate (cfun->eh->lp_array, i, &lp); ++i)
if (lp && lp->post_landing_pad)
{
int action, call_site;
/* First: build the action table. */
action = collect_one_action_chain (&ar_hash, lp->region);
/* Next: assign call-site values. If dwarf2 terms, this would be
the region number assigned by convert_to_eh_region_ranges, but
handles no-action and must-not-throw differently. */
/* Map must-not-throw to otherwise unused call-site index 0. */
if (action == -2)
call_site = 0;
/* Map no-action to otherwise unused call-site index -1. */
else if (action == -1)
call_site = -1;
/* Otherwise, look it up in the table. */
else
call_site = add_call_site (GEN_INT (disp_index), action, 0);
sjlj_lp_call_site_index[i] = call_site;
disp_index++;
}
return disp_index;
}
/* Emit code to record the current call-site index before every
insn that can throw. */
static void
sjlj_mark_call_sites (void)
{
int last_call_site = -2;
rtx_insn *insn;
rtx mem;
for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
{
eh_landing_pad lp;
eh_region r;
bool nothrow;
int this_call_site;
rtx_insn *before, *p;
/* Reset value tracking at extended basic block boundaries. */
if (LABEL_P (insn))
last_call_site = -2;
/* If the function allocates dynamic stack space, the context must
be updated after every allocation/deallocation accordingly. */
if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_UPDATE_SJLJ_CONTEXT)
{
rtx buf_addr;
start_sequence ();
buf_addr = plus_constant (Pmode, XEXP (crtl->eh.sjlj_fc, 0),
sjlj_fc_jbuf_ofs);
expand_builtin_update_setjmp_buf (buf_addr);
p = get_insns ();
end_sequence ();
emit_insn_before (p, insn);
}
if (! INSN_P (insn))
continue;
nothrow = get_eh_region_and_lp_from_rtx (insn, &r, &lp);
if (nothrow)
continue;
if (lp)
this_call_site = sjlj_lp_call_site_index[lp->index];
else if (r == NULL)
{
/* Calls (and trapping insns) without notes are outside any
exception handling region in this function. Mark them as
no action. */
this_call_site = -1;
}
else
{
gcc_assert (r->type == ERT_MUST_NOT_THROW);
this_call_site = 0;
}
if (this_call_site != -1)
crtl->uses_eh_lsda = 1;
if (this_call_site == last_call_site)
continue;
/* Don't separate a call from it's argument loads. */
before = insn;
if (CALL_P (insn))
before = find_first_parameter_load (insn, NULL);
start_sequence ();
mem = adjust_address (crtl->eh.sjlj_fc, TYPE_MODE (integer_type_node),
sjlj_fc_call_site_ofs);
emit_move_insn (mem, gen_int_mode (this_call_site, GET_MODE (mem)));
p = get_insns ();
end_sequence ();
emit_insn_before (p, before);
last_call_site = this_call_site;
}
}
/* Construct the SjLj_Function_Context. */
static void
sjlj_emit_function_enter (rtx_code_label *dispatch_label)
{
rtx_insn *fn_begin, *seq;
rtx fc, mem;
bool fn_begin_outside_block;
rtx personality = get_personality_function (current_function_decl);
fc = crtl->eh.sjlj_fc;
start_sequence ();
/* We're storing this libcall's address into memory instead of
calling it directly. Thus, we must call assemble_external_libcall
here, as we cannot depend on emit_library_call to do it for us. */
assemble_external_libcall (personality);
mem = adjust_address (fc, Pmode, sjlj_fc_personality_ofs);
emit_move_insn (mem, personality);
mem = adjust_address (fc, Pmode, sjlj_fc_lsda_ofs);
if (crtl->uses_eh_lsda)
{
char buf[20];
rtx sym;
ASM_GENERATE_INTERNAL_LABEL (buf, "LLSDA", current_function_funcdef_no);
sym = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (buf));
SYMBOL_REF_FLAGS (sym) = SYMBOL_FLAG_LOCAL;
emit_move_insn (mem, sym);
}
else
emit_move_insn (mem, const0_rtx);
if (dispatch_label)
{
rtx addr = plus_constant (Pmode, XEXP (fc, 0), sjlj_fc_jbuf_ofs);
#ifdef DONT_USE_BUILTIN_SETJMP
addr = copy_addr_to_reg (addr);
addr = convert_memory_address (ptr_mode, addr);
tree addr_tree = make_tree (ptr_type_node, addr);
tree call_expr = build_call_expr (setjmp_fn, 1, addr_tree);
rtx x = expand_call (call_expr, NULL_RTX, false);
emit_cmp_and_jump_insns (x, const0_rtx, NE, 0,
TYPE_MODE (integer_type_node), 0,
dispatch_label,
profile_probability::unlikely ());
#else
expand_builtin_setjmp_setup (addr, dispatch_label);
#endif
}
emit_library_call (unwind_sjlj_register_libfunc, LCT_NORMAL, VOIDmode,
XEXP (fc, 0), Pmode);
seq = get_insns ();
end_sequence ();
/* ??? Instead of doing this at the beginning of the function,
do this in a block that is at loop level 0 and dominates all
can_throw_internal instructions. */
fn_begin_outside_block = true;
for (fn_begin = get_insns (); ; fn_begin = NEXT_INSN (fn_begin))
if (NOTE_P (fn_begin))
{
if (NOTE_KIND (fn_begin) == NOTE_INSN_FUNCTION_BEG)
break;
else if (NOTE_INSN_BASIC_BLOCK_P (fn_begin))
fn_begin_outside_block = false;
}
#ifdef DONT_USE_BUILTIN_SETJMP
if (dispatch_label)
{
/* The sequence contains a branch in the middle so we need to force
the creation of a new basic block by means of BB_SUPERBLOCK. */
if (fn_begin_outside_block)
{
basic_block bb
= split_edge (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
if (JUMP_P (BB_END (bb)))
emit_insn_before (seq, BB_END (bb));
else
emit_insn_after (seq, BB_END (bb));
}
else
emit_insn_after (seq, fn_begin);
single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))->flags |= BB_SUPERBLOCK;
return;
}
#endif
if (fn_begin_outside_block)
insert_insn_on_edge (seq, single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
else
emit_insn_after (seq, fn_begin);
}
/* Call back from expand_function_end to know where we should put
the call to unwind_sjlj_unregister_libfunc if needed. */
void
sjlj_emit_function_exit_after (rtx_insn *after)
{
crtl->eh.sjlj_exit_after = after;
}
static void
sjlj_emit_function_exit (void)
{
rtx_insn *seq, *insn;
start_sequence ();
emit_library_call (unwind_sjlj_unregister_libfunc, LCT_NORMAL, VOIDmode,
XEXP (crtl->eh.sjlj_fc, 0), Pmode);
seq = get_insns ();
end_sequence ();
/* ??? Really this can be done in any block at loop level 0 that
post-dominates all can_throw_internal instructions. This is
the last possible moment. */
insn = crtl->eh.sjlj_exit_after;
if (LABEL_P (insn))
insn = NEXT_INSN (insn);
emit_insn_after (seq, insn);
}
static void
sjlj_emit_dispatch_table (rtx_code_label *dispatch_label, int num_dispatch)
{
scalar_int_mode unwind_word_mode = targetm.unwind_word_mode ();
scalar_int_mode filter_mode = targetm.eh_return_filter_mode ();
eh_landing_pad lp;
rtx mem, fc, exc_ptr_reg, filter_reg;
rtx_insn *seq;
basic_block bb;
eh_region r;
int i, disp_index;
vec<tree> dispatch_labels = vNULL;
fc = crtl->eh.sjlj_fc;
start_sequence ();
emit_label (dispatch_label);
#ifndef DONT_USE_BUILTIN_SETJMP
expand_builtin_setjmp_receiver (dispatch_label);
/* The caller of expand_builtin_setjmp_receiver is responsible for
making sure that the label doesn't vanish. The only other caller
is the expander for __builtin_setjmp_receiver, which places this
label on the nonlocal_goto_label list. Since we're modeling these
CFG edges more exactly, we can use the forced_labels list instead. */
LABEL_PRESERVE_P (dispatch_label) = 1;
vec_safe_push<rtx_insn *> (forced_labels, dispatch_label);
#endif
/* Load up exc_ptr and filter values from the function context. */
mem = adjust_address (fc, unwind_word_mode, sjlj_fc_data_ofs);
if (unwind_word_mode != ptr_mode)
{
#ifdef POINTERS_EXTEND_UNSIGNED
mem = convert_memory_address (ptr_mode, mem);
#else
mem = convert_to_mode (ptr_mode, mem, 0);
#endif
}
exc_ptr_reg = force_reg (ptr_mode, mem);
mem = adjust_address (fc, unwind_word_mode,
sjlj_fc_data_ofs + GET_MODE_SIZE (unwind_word_mode));
if (unwind_word_mode != filter_mode)
mem = convert_to_mode (filter_mode, mem, 0);
filter_reg = force_reg (filter_mode, mem);
/* Jump to one of the directly reachable regions. */
disp_index = 0;
rtx_code_label *first_reachable_label = NULL;
/* If there's exactly one call site in the function, don't bother
generating a switch statement. */
if (num_dispatch > 1)
dispatch_labels.create (num_dispatch);
for (i = 1; vec_safe_iterate (cfun->eh->lp_array, i, &lp); ++i)
if (lp && lp->post_landing_pad)
{
rtx_insn *seq2;
rtx_code_label *label;
start_sequence ();
lp->landing_pad = dispatch_label;
if (num_dispatch > 1)
{
tree t_label, case_elt, t;
t_label = create_artificial_label (UNKNOWN_LOCATION);
t = build_int_cst (integer_type_node, disp_index);
case_elt = build_case_label (t, NULL, t_label);
dispatch_labels.quick_push (case_elt);
label = jump_target_rtx (t_label);
}
else
label = gen_label_rtx ();
if (disp_index == 0)
first_reachable_label = label;
emit_label (label);
r = lp->region;
if (r->exc_ptr_reg)
emit_move_insn (r->exc_ptr_reg, exc_ptr_reg);
if (r->filter_reg)
emit_move_insn (r->filter_reg, filter_reg);
seq2 = get_insns ();
end_sequence ();
rtx_insn *before = label_rtx (lp->post_landing_pad);
bb = emit_to_new_bb_before (seq2, before);
make_single_succ_edge (bb, bb->next_bb, EDGE_FALLTHRU);
if (current_loops)
{
class loop *loop = bb->next_bb->loop_father;
/* If we created a pre-header block, add the new block to the
outer loop, otherwise to the loop itself. */
if (bb->next_bb == loop->header)
add_bb_to_loop (bb, loop_outer (loop));
else
add_bb_to_loop (bb, loop);
/* ??? For multiple dispatches we will end up with edges
from the loop tree root into this loop, making it a
multiple-entry loop. Discard all affected loops. */
if (num_dispatch > 1)
{
for (loop = bb->loop_father;
loop_outer (loop); loop = loop_outer (loop))
mark_loop_for_removal (loop);
}
}
disp_index++;
}
gcc_assert (disp_index == num_dispatch);
if (num_dispatch > 1)
{
rtx disp = adjust_address (fc, TYPE_MODE (integer_type_node),
sjlj_fc_call_site_ofs);
expand_sjlj_dispatch_table (disp, dispatch_labels);
}
seq = get_insns ();
end_sequence ();
bb = emit_to_new_bb_before (seq, first_reachable_label);
if (num_dispatch == 1)
{
make_single_succ_edge (bb, bb->next_bb, EDGE_FALLTHRU);
if (current_loops)
{
class loop *loop = bb->next_bb->loop_father;
/* If we created a pre-header block, add the new block to the
outer loop, otherwise to the loop itself. */
if (bb->next_bb == loop->header)
add_bb_to_loop (bb, loop_outer (loop));
else
add_bb_to_loop (bb, loop);
}
}
else
{
/* We are not wiring up edges here, but as the dispatcher call
is at function begin simply associate the block with the
outermost (non-)loop. */
if (current_loops)
add_bb_to_loop (bb, current_loops->tree_root);
}
}
static void
sjlj_build_landing_pads (void)
{
int num_dispatch;
num_dispatch = vec_safe_length (cfun->eh->lp_array);
if (num_dispatch == 0)
return;
sjlj_lp_call_site_index.safe_grow_cleared (num_dispatch, true);
num_dispatch = sjlj_assign_call_site_values ();
if (num_dispatch > 0)
{
rtx_code_label *dispatch_label = gen_label_rtx ();
int align = STACK_SLOT_ALIGNMENT (sjlj_fc_type_node,
TYPE_MODE (sjlj_fc_type_node),
TYPE_ALIGN (sjlj_fc_type_node));
crtl->eh.sjlj_fc
= assign_stack_local (TYPE_MODE (sjlj_fc_type_node),
int_size_in_bytes (sjlj_fc_type_node),
align);
sjlj_mark_call_sites ();
sjlj_emit_function_enter (dispatch_label);
sjlj_emit_dispatch_table (dispatch_label, num_dispatch);
sjlj_emit_function_exit ();
}
/* If we do not have any landing pads, we may still need to register a
personality routine and (empty) LSDA to handle must-not-throw regions. */
else if (function_needs_eh_personality (cfun) != eh_personality_none)
{
int align = STACK_SLOT_ALIGNMENT (sjlj_fc_type_node,
TYPE_MODE (sjlj_fc_type_node),
TYPE_ALIGN (sjlj_fc_type_node));
crtl->eh.sjlj_fc
= assign_stack_local (TYPE_MODE (sjlj_fc_type_node),
int_size_in_bytes (sjlj_fc_type_node),
align);
sjlj_mark_call_sites ();
sjlj_emit_function_enter (NULL);
sjlj_emit_function_exit ();
}
sjlj_lp_call_site_index.release ();
}
/* Update the sjlj function context. This function should be called
whenever we allocate or deallocate dynamic stack space. */
void
update_sjlj_context (void)
{
if (!flag_exceptions)
return;
emit_note (NOTE_INSN_UPDATE_SJLJ_CONTEXT);
}
/* After initial rtl generation, call back to finish generating
exception support code. */
void
finish_eh_generation (void)
{
basic_block bb;
/* Construct the landing pads. */
if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ)
sjlj_build_landing_pads ();
else
dw2_build_landing_pads ();
break_superblocks ();
/* Redirect all EH edges from the post_landing_pad to the landing pad. */
FOR_EACH_BB_FN (bb, cfun)
{
eh_landing_pad lp;
edge_iterator ei;
edge e;
lp = get_eh_landing_pad_from_rtx (BB_END (bb));
FOR_EACH_EDGE (e, ei, bb->succs)
if (e->flags & EDGE_EH)
break;
/* We should not have generated any new throwing insns during this
pass, and we should not have lost any EH edges, so we only need
to handle two cases here:
(1) reachable handler and an existing edge to post-landing-pad,
(2) no reachable handler and no edge. */
gcc_assert ((lp != NULL) == (e != NULL));
if (lp != NULL)
{
gcc_assert (BB_HEAD (e->dest) == label_rtx (lp->post_landing_pad));
redirect_edge_succ (e, BLOCK_FOR_INSN (lp->landing_pad));
e->flags |= (CALL_P (BB_END (bb))
? EDGE_ABNORMAL | EDGE_ABNORMAL_CALL
: EDGE_ABNORMAL);
}
}
if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ
/* Kludge for Alpha (see alpha_gp_save_rtx). */
|| single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))->insns.r)
commit_edge_insertions ();
}
/* This section handles removing dead code for flow. */
void
remove_eh_landing_pad (eh_landing_pad lp)
{
eh_landing_pad *pp;
for (pp = &lp->region->landing_pads; *pp != lp; pp = &(*pp)->next_lp)
continue;
*pp = lp->next_lp;
if (lp->post_landing_pad)
EH_LANDING_PAD_NR (lp->post_landing_pad) = 0;
(*cfun->eh->lp_array)[lp->index] = NULL;
}
/* Splice the EH region at PP from the region tree. */
static void
remove_eh_handler_splicer (eh_region *pp)
{
eh_region region = *pp;
eh_landing_pad lp;
for (lp = region->landing_pads; lp ; lp = lp->next_lp)
{
if (lp->post_landing_pad)
EH_LANDING_PAD_NR (lp->post_landing_pad) = 0;
(*cfun->eh->lp_array)[lp->index] = NULL;
}
if (region->inner)
{
eh_region p, outer;
outer = region->outer;
*pp = p = region->inner;
do
{
p->outer = outer;
pp = &p->next_peer;
p = *pp;
}
while (p);
}
*pp = region->next_peer;
(*cfun->eh->region_array)[region->index] = NULL;
}
/* Splice a single EH region REGION from the region tree.
To unlink REGION, we need to find the pointer to it with a relatively
expensive search in REGION's outer region. If you are going to
remove a number of handlers, using remove_unreachable_eh_regions may
be a better option. */
void
remove_eh_handler (eh_region region)
{
eh_region *pp, *pp_start, p, outer;
outer = region->outer;
if (outer)
pp_start = &outer->inner;
else
pp_start = &cfun->eh->region_tree;
for (pp = pp_start, p = *pp; p != region; pp = &p->next_peer, p = *pp)
continue;
remove_eh_handler_splicer (pp);
}
/* Worker for remove_unreachable_eh_regions.
PP is a pointer to the region to start a region tree depth-first
search from. R_REACHABLE is the set of regions that have to be
preserved. */
static void
remove_unreachable_eh_regions_worker (eh_region *pp, sbitmap r_reachable)
{
while (*pp)
{
eh_region region = *pp;
remove_unreachable_eh_regions_worker (&region->inner, r_reachable);
if (!bitmap_bit_p (r_reachable, region->index))
remove_eh_handler_splicer (pp);
else
pp = &region->next_peer;
}
}
/* Splice all EH regions *not* marked in R_REACHABLE from the region tree.
Do this by traversing the EH tree top-down and splice out regions that
are not marked. By removing regions from the leaves, we avoid costly
searches in the region tree. */
void
remove_unreachable_eh_regions (sbitmap r_reachable)
{
remove_unreachable_eh_regions_worker (&cfun->eh->region_tree, r_reachable);
}
/* Invokes CALLBACK for every exception handler landing pad label.
Only used by reload hackery; should not be used by new code. */
void
for_each_eh_label (void (*callback) (rtx))
{
eh_landing_pad lp;
int i;
for (i = 1; vec_safe_iterate (cfun->eh->lp_array, i, &lp); ++i)
{
if (lp)
{
rtx_code_label *lab = lp->landing_pad;
if (lab && LABEL_P (lab))
(*callback) (lab);
}
}
}
/* Create the REG_EH_REGION note for INSN, given its ECF_FLAGS for a
call insn.
At the gimple level, we use LP_NR
> 0 : The statement transfers to landing pad LP_NR
= 0 : The statement is outside any EH region
< 0 : The statement is within MUST_NOT_THROW region -LP_NR.
At the rtl level, we use LP_NR
> 0 : The insn transfers to landing pad LP_NR
= 0 : The insn cannot throw
< 0 : The insn is within MUST_NOT_THROW region -LP_NR
= INT_MIN : The insn cannot throw or execute a nonlocal-goto.
missing note: The insn is outside any EH region.
??? This difference probably ought to be avoided. We could stand
to record nothrow for arbitrary gimple statements, and so avoid
some moderately complex lookups in stmt_could_throw_p. Perhaps
NOTHROW should be mapped on both sides to INT_MIN. Perhaps the
no-nonlocal-goto property should be recorded elsewhere as a bit
on the call_insn directly. Perhaps we should make more use of
attaching the trees to call_insns (reachable via symbol_ref in
direct call cases) and just pull the data out of the trees. */
void
make_reg_eh_region_note (rtx_insn *insn, int ecf_flags, int lp_nr)
{
rtx value;
if (ecf_flags & ECF_NOTHROW)
value = const0_rtx;
else if (lp_nr != 0)
value = GEN_INT (lp_nr);
else
return;
add_reg_note (insn, REG_EH_REGION, value);
}
/* Create a REG_EH_REGION note for a CALL_INSN that cannot throw
nor perform a non-local goto. Replace the region note if it
already exists. */
void
make_reg_eh_region_note_nothrow_nononlocal (rtx_insn *insn)
{
rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
rtx intmin = GEN_INT (INT_MIN);
if (note != 0)
XEXP (note, 0) = intmin;
else
add_reg_note (insn, REG_EH_REGION, intmin);
}
/* Return true if INSN could throw, assuming no REG_EH_REGION note
to the contrary. */
bool
insn_could_throw_p (const_rtx insn)
{
if (!flag_exceptions)
return false;
if (CALL_P (insn))
return true;
if (INSN_P (insn) && cfun->can_throw_non_call_exceptions)
return may_trap_p (PATTERN (insn));
return false;
}
/* Copy an REG_EH_REGION note to each insn that might throw beginning
at FIRST and ending at LAST. NOTE_OR_INSN is either the source insn
to look for a note, or the note itself. */
void
copy_reg_eh_region_note_forward (rtx note_or_insn, rtx_insn *first, rtx last)
{
rtx_insn *insn;
rtx note = note_or_insn;
if (INSN_P (note_or_insn))
{
note = find_reg_note (note_or_insn, REG_EH_REGION, NULL_RTX);
if (note == NULL)
return;
}
else if (is_a <rtx_insn *> (note_or_insn))
return;
note = XEXP (note, 0);
for (insn = first; insn != last ; insn = NEXT_INSN (insn))
if (!find_reg_note (insn, REG_EH_REGION, NULL_RTX)
&& insn_could_throw_p (insn))
add_reg_note (insn, REG_EH_REGION, note);
}
/* Likewise, but iterate backward. */
void
copy_reg_eh_region_note_backward (rtx note_or_insn, rtx_insn *last, rtx first)
{
rtx_insn *insn;
rtx note = note_or_insn;
if (INSN_P (note_or_insn))
{
note = find_reg_note (note_or_insn, REG_EH_REGION, NULL_RTX);
if (note == NULL)
return;
}
else if (is_a <rtx_insn *> (note_or_insn))
return;
note = XEXP (note, 0);
for (insn = last; insn != first; insn = PREV_INSN (insn))
if (insn_could_throw_p (insn))
add_reg_note (insn, REG_EH_REGION, note);
}
/* Extract all EH information from INSN. Return true if the insn
was marked NOTHROW. */
static bool
get_eh_region_and_lp_from_rtx (const_rtx insn, eh_region *pr,
eh_landing_pad *plp)
{
eh_landing_pad lp = NULL;
eh_region r = NULL;
bool ret = false;
rtx note;
int lp_nr;
if (! INSN_P (insn))
goto egress;
if (NONJUMP_INSN_P (insn)
&& GET_CODE (PATTERN (insn)) == SEQUENCE)
insn = XVECEXP (PATTERN (insn), 0, 0);
note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
if (!note)
{
ret = !insn_could_throw_p (insn);
goto egress;
}
lp_nr = INTVAL (XEXP (note, 0));
if (lp_nr == 0 || lp_nr == INT_MIN)
{
ret = true;
goto egress;
}
if (lp_nr < 0)
r = (*cfun->eh->region_array)[-lp_nr];
else
{
lp = (*cfun->eh->lp_array)[lp_nr];
r = lp->region;
}
egress:
*plp = lp;
*pr = r;
return ret;
}
/* Return the landing pad to which INSN may go, or NULL if it does not
have a reachable landing pad within this function. */
eh_landing_pad
get_eh_landing_pad_from_rtx (const_rtx insn)
{
eh_landing_pad lp;
eh_region r;
get_eh_region_and_lp_from_rtx (insn, &r, &lp);
return lp;
}
/* Return the region to which INSN may go, or NULL if it does not
have a reachable region within this function. */
eh_region
get_eh_region_from_rtx (const_rtx insn)
{
eh_landing_pad lp;
eh_region r;
get_eh_region_and_lp_from_rtx (insn, &r, &lp);
return r;
}
/* Return true if INSN throws and is caught by something in this function. */
bool
can_throw_internal (const_rtx insn)
{
return get_eh_landing_pad_from_rtx (insn) != NULL;
}
/* Return true if INSN throws and escapes from the current function. */
bool
can_throw_external (const_rtx insn)
{
eh_landing_pad lp;
eh_region r;
bool nothrow;
if (! INSN_P (insn))
return false;
if (NONJUMP_INSN_P (insn)
&& GET_CODE (PATTERN (insn)) == SEQUENCE)
{
rtx_sequence *seq = as_a <rtx_sequence *> (PATTERN (insn));
int i, n = seq->len ();
for (i = 0; i < n; i++)
if (can_throw_external (seq->element (i)))
return true;
return false;
}
nothrow = get_eh_region_and_lp_from_rtx (insn, &r, &lp);
/* If we can't throw, we obviously can't throw external. */
if (nothrow)
return false;
/* If we have an internal landing pad, then we're not external. */
if (lp != NULL)
return false;
/* If we're not within an EH region, then we are external. */
if (r == NULL)
return true;
/* The only thing that ought to be left is MUST_NOT_THROW regions,
which don't always have landing pads. */
gcc_assert (r->type == ERT_MUST_NOT_THROW);
return false;
}
/* Return true if INSN cannot throw at all. */
bool
insn_nothrow_p (const_rtx insn)
{
eh_landing_pad lp;
eh_region r;
if (! INSN_P (insn))
return true;
if (NONJUMP_INSN_P (insn)
&& GET_CODE (PATTERN (insn)) == SEQUENCE)
{
rtx_sequence *seq = as_a <rtx_sequence *> (PATTERN (insn));
int i, n = seq->len ();
for (i = 0; i < n; i++)
if (!insn_nothrow_p (seq->element (i)))
return false;
return true;
}
return get_eh_region_and_lp_from_rtx (insn, &r, &lp);
}
/* Return true if INSN can perform a non-local goto. */
/* ??? This test is here in this file because it (ab)uses REG_EH_REGION. */
bool
can_nonlocal_goto (const rtx_insn *insn)
{
if (nonlocal_goto_handler_labels && CALL_P (insn))
{
rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
if (!note || INTVAL (XEXP (note, 0)) != INT_MIN)
return true;
}
return false;
}
/* Set TREE_NOTHROW and crtl->all_throwers_are_sibcalls. */
static unsigned int
set_nothrow_function_flags (void)
{
rtx_insn *insn;
crtl->nothrow = 1;
/* Assume crtl->all_throwers_are_sibcalls until we encounter
something that can throw an exception. We specifically exempt
CALL_INSNs that are SIBLING_CALL_P, as these are really jumps,
and can't throw. Most CALL_INSNs are not SIBLING_CALL_P, so this
is optimistic. */
crtl->all_throwers_are_sibcalls = 1;
/* If we don't know that this implementation of the function will
actually be used, then we must not set TREE_NOTHROW, since
callers must not assume that this function does not throw. */
if (TREE_NOTHROW (current_function_decl))
return 0;
if (! flag_exceptions)
return 0;
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
if (can_throw_external (insn))
{
crtl->nothrow = 0;
if (!CALL_P (insn) || !SIBLING_CALL_P (insn))
{
crtl->all_throwers_are_sibcalls = 0;
return 0;
}
}
if (crtl->nothrow
&& (cgraph_node::get (current_function_decl)->get_availability ()
>= AVAIL_AVAILABLE))
{
struct cgraph_node *node = cgraph_node::get (current_function_decl);
struct cgraph_edge *e;
for (e = node->callers; e; e = e->next_caller)
e->can_throw_external = false;
node->set_nothrow_flag (true);
if (dump_file)
fprintf (dump_file, "Marking function nothrow: %s\n\n",
current_function_name ());
}
return 0;
}
namespace {
const pass_data pass_data_set_nothrow_function_flags =
{
RTL_PASS, /* type */
"nothrow", /* name */
OPTGROUP_NONE, /* optinfo_flags */
TV_NONE, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
0, /* todo_flags_finish */
};
class pass_set_nothrow_function_flags : public rtl_opt_pass
{
public:
pass_set_nothrow_function_flags (gcc::context *ctxt)
: rtl_opt_pass (pass_data_set_nothrow_function_flags, ctxt)
{}
/* opt_pass methods: */
virtual unsigned int execute (function *)
{
return set_nothrow_function_flags ();
}
}; // class pass_set_nothrow_function_flags
} // anon namespace
rtl_opt_pass *
make_pass_set_nothrow_function_flags (gcc::context *ctxt)
{
return new pass_set_nothrow_function_flags (ctxt);
}
/* Various hooks for unwind library. */
/* Expand the EH support builtin functions:
__builtin_eh_pointer and __builtin_eh_filter. */
static eh_region
expand_builtin_eh_common (tree region_nr_t)
{
HOST_WIDE_INT region_nr;
eh_region region;
gcc_assert (tree_fits_shwi_p (region_nr_t));
region_nr = tree_to_shwi (region_nr_t);
region = (*cfun->eh->region_array)[region_nr];
/* ??? We shouldn't have been able to delete a eh region without
deleting all the code that depended on it. */
gcc_assert (region != NULL);
return region;
}
/* Expand to the exc_ptr value from the given eh region. */
rtx
expand_builtin_eh_pointer (tree exp)
{
eh_region region
= expand_builtin_eh_common (CALL_EXPR_ARG (exp, 0));
if (region->exc_ptr_reg == NULL)
region->exc_ptr_reg = gen_reg_rtx (ptr_mode);
return region->exc_ptr_reg;
}
/* Expand to the filter value from the given eh region. */
rtx
expand_builtin_eh_filter (tree exp)
{
eh_region region
= expand_builtin_eh_common (CALL_EXPR_ARG (exp, 0));
if (region->filter_reg == NULL)
region->filter_reg = gen_reg_rtx (targetm.eh_return_filter_mode ());
return region->filter_reg;
}
/* Copy the exc_ptr and filter values from one landing pad's registers
to another. This is used to inline the resx statement. */
rtx
expand_builtin_eh_copy_values (tree exp)
{
eh_region dst
= expand_builtin_eh_common (CALL_EXPR_ARG (exp, 0));
eh_region src
= expand_builtin_eh_common (CALL_EXPR_ARG (exp, 1));
scalar_int_mode fmode = targetm.eh_return_filter_mode ();
if (dst->exc_ptr_reg == NULL)
dst->exc_ptr_reg = gen_reg_rtx (ptr_mode);
if (src->exc_ptr_reg == NULL)
src->exc_ptr_reg = gen_reg_rtx (ptr_mode);
if (dst->filter_reg == NULL)
dst->filter_reg = gen_reg_rtx (fmode);
if (src->filter_reg == NULL)
src->filter_reg = gen_reg_rtx (fmode);
emit_move_insn (dst->exc_ptr_reg, src->exc_ptr_reg);
emit_move_insn (dst->filter_reg, src->filter_reg);
return const0_rtx;
}
/* Do any necessary initialization to access arbitrary stack frames.
On the SPARC, this means flushing the register windows. */
void
expand_builtin_unwind_init (void)
{
/* Set this so all the registers get saved in our frame; we need to be
able to copy the saved values for any registers from frames we unwind. */
crtl->saves_all_registers = 1;
SETUP_FRAME_ADDRESSES ();
}
/* Map a non-negative number to an eh return data register number; expands
to -1 if no return data register is associated with the input number.
At least the inputs 0 and 1 must be mapped; the target may provide more. */
rtx
expand_builtin_eh_return_data_regno (tree exp)
{
tree which = CALL_EXPR_ARG (exp, 0);
unsigned HOST_WIDE_INT iwhich;
if (TREE_CODE (which) != INTEGER_CST)
{
error ("argument of %<__builtin_eh_return_regno%> must be constant");
return constm1_rtx;
}
iwhich = tree_to_uhwi (which);
iwhich = EH_RETURN_DATA_REGNO (iwhich);
if (iwhich == INVALID_REGNUM)
return constm1_rtx;
#ifdef DWARF_FRAME_REGNUM
iwhich = DWARF_FRAME_REGNUM (iwhich);
#else
iwhich = DBX_REGISTER_NUMBER (iwhich);
#endif
return GEN_INT (iwhich);
}
/* Given a value extracted from the return address register or stack slot,
return the actual address encoded in that value. */
rtx
expand_builtin_extract_return_addr (tree addr_tree)
{
rtx addr = expand_expr (addr_tree, NULL_RTX, Pmode, EXPAND_NORMAL);
if (GET_MODE (addr) != Pmode
&& GET_MODE (addr) != VOIDmode)
{
#ifdef POINTERS_EXTEND_UNSIGNED
addr = convert_memory_address (Pmode, addr);
#else
addr = convert_to_mode (Pmode, addr, 0);
#endif
}
/* First mask out any unwanted bits. */
rtx mask = MASK_RETURN_ADDR;
if (mask)
expand_and (Pmode, addr, mask, addr);
/* Then adjust to find the real return address. */
if (RETURN_ADDR_OFFSET)
addr = plus_constant (Pmode, addr, RETURN_ADDR_OFFSET);
return addr;
}
/* Given an actual address in addr_tree, do any necessary encoding
and return the value to be stored in the return address register or
stack slot so the epilogue will return to that address. */
rtx
expand_builtin_frob_return_addr (tree addr_tree)
{
rtx addr = expand_expr (addr_tree, NULL_RTX, ptr_mode, EXPAND_NORMAL);
addr = convert_memory_address (Pmode, addr);
if (RETURN_ADDR_OFFSET)
{
addr = force_reg (Pmode, addr);
addr = plus_constant (Pmode, addr, -RETURN_ADDR_OFFSET);
}
return addr;
}
/* Set up the epilogue with the magic bits we'll need to return to the
exception handler. */
void
expand_builtin_eh_return (tree stackadj_tree ATTRIBUTE_UNUSED,
tree handler_tree)
{
rtx tmp;
#ifdef EH_RETURN_STACKADJ_RTX
tmp = expand_expr (stackadj_tree, crtl->eh.ehr_stackadj,
VOIDmode, EXPAND_NORMAL);
tmp = convert_memory_address (Pmode, tmp);
if (!crtl->eh.ehr_stackadj)
crtl->eh.ehr_stackadj = copy_addr_to_reg (tmp);
else if (tmp != crtl->eh.ehr_stackadj)
emit_move_insn (crtl->eh.ehr_stackadj, tmp);
#endif
tmp = expand_expr (handler_tree, crtl->eh.ehr_handler,
VOIDmode, EXPAND_NORMAL);
tmp = convert_memory_address (Pmode, tmp);
if (!crtl->eh.ehr_handler)
crtl->eh.ehr_handler = copy_addr_to_reg (tmp);
else if (tmp != crtl->eh.ehr_handler)
emit_move_insn (crtl->eh.ehr_handler, tmp);
if (!crtl->eh.ehr_label)
crtl->eh.ehr_label = gen_label_rtx ();
emit_jump (crtl->eh.ehr_label);
}
/* Expand __builtin_eh_return. This exit path from the function loads up
the eh return data registers, adjusts the stack, and branches to a
given PC other than the normal return address. */
void
expand_eh_return (void)
{
rtx_code_label *around_label;
if (! crtl->eh.ehr_label)
return;
crtl->calls_eh_return = 1;
#ifdef EH_RETURN_STACKADJ_RTX
emit_move_insn (EH_RETURN_STACKADJ_RTX, const0_rtx);
#endif
around_label = gen_label_rtx ();
emit_jump (around_label);
emit_label (crtl->eh.ehr_label);
clobber_return_register ();
#ifdef EH_RETURN_STACKADJ_RTX
emit_move_insn (EH_RETURN_STACKADJ_RTX, crtl->eh.ehr_stackadj);
#endif
if (targetm.have_eh_return ())
emit_insn (targetm.gen_eh_return (crtl->eh.ehr_handler));
else
{
if (rtx handler = EH_RETURN_HANDLER_RTX)
emit_move_insn (handler, crtl->eh.ehr_handler);
else
error ("%<__builtin_eh_return%> not supported on this target");
}
emit_label (around_label);
}
/* Convert a ptr_mode address ADDR_TREE to a Pmode address controlled by
POINTERS_EXTEND_UNSIGNED and return it. */
rtx
expand_builtin_extend_pointer (tree addr_tree)
{
rtx addr = expand_expr (addr_tree, NULL_RTX, ptr_mode, EXPAND_NORMAL);
int extend;
#ifdef POINTERS_EXTEND_UNSIGNED
extend = POINTERS_EXTEND_UNSIGNED;
#else
/* The previous EH code did an unsigned extend by default, so we do this also
for consistency. */
extend = 1;
#endif
return convert_modes (targetm.unwind_word_mode (), ptr_mode, addr, extend);
}
static int
add_action_record (action_hash_type *ar_hash, int filter, int next)
{
struct action_record **slot, *new_ar, tmp;
tmp.filter = filter;
tmp.next = next;
slot = ar_hash->find_slot (&tmp, INSERT);
if ((new_ar = *slot) == NULL)
{
new_ar = XNEW (struct action_record);
new_ar->offset = crtl->eh.action_record_data->length () + 1;
new_ar->filter = filter;
new_ar->next = next;
*slot = new_ar;
/* The filter value goes in untouched. The link to the next
record is a "self-relative" byte offset, or zero to indicate
that there is no next record. So convert the absolute 1 based
indices we've been carrying around into a displacement. */
push_sleb128 (&crtl->eh.action_record_data, filter);
if (next)
next -= crtl->eh.action_record_data->length () + 1;
push_sleb128 (&crtl->eh.action_record_data, next);
}
return new_ar->offset;
}
static int
collect_one_action_chain (action_hash_type *ar_hash, eh_region region)
{
int next;
/* If we've reached the top of the region chain, then we have
no actions, and require no landing pad. */
if (region == NULL)
return -1;
switch (region->type)
{
case ERT_CLEANUP:
{
eh_region r;
/* A cleanup adds a zero filter to the beginning of the chain, but
there are special cases to look out for. If there are *only*
cleanups along a path, then it compresses to a zero action.
Further, if there are multiple cleanups along a path, we only
need to represent one of them, as that is enough to trigger
entry to the landing pad at runtime. */
next = collect_one_action_chain (ar_hash, region->outer);
if (next <= 0)
return 0;
for (r = region->outer; r ; r = r->outer)
if (r->type == ERT_CLEANUP)
return next;
return add_action_record (ar_hash, 0, next);
}
case ERT_TRY:
{
eh_catch c;
/* Process the associated catch regions in reverse order.
If there's a catch-all handler, then we don't need to
search outer regions. Use a magic -3 value to record
that we haven't done the outer search. */
next = -3;
for (c = region->u.eh_try.last_catch; c ; c = c->prev_catch)
{
if (c->type_list == NULL)
{
/* Retrieve the filter from the head of the filter list
where we have stored it (see assign_filter_values). */
int filter = TREE_INT_CST_LOW (TREE_VALUE (c->filter_list));
next = add_action_record (ar_hash, filter, 0);
}
else
{
/* Once the outer search is done, trigger an action record for
each filter we have. */
tree flt_node;
if (next == -3)
{
next = collect_one_action_chain (ar_hash, region->outer);
/* If there is no next action, terminate the chain. */
if (next == -1)
next = 0;
/* If all outer actions are cleanups or must_not_throw,
we'll have no action record for it, since we had wanted
to encode these states in the call-site record directly.
Add a cleanup action to the chain to catch these. */
else if (next <= 0)
next = add_action_record (ar_hash, 0, 0);
}
flt_node = c->filter_list;
for (; flt_node; flt_node = TREE_CHAIN (flt_node))
{
int filter = TREE_INT_CST_LOW (TREE_VALUE (flt_node));
next = add_action_record (ar_hash, filter, next);
}
}
}
return next;
}
case ERT_ALLOWED_EXCEPTIONS:
/* An exception specification adds its filter to the
beginning of the chain. */
next = collect_one_action_chain (ar_hash, region->outer);
/* If there is no next action, terminate the chain. */
if (next == -1)
next = 0;
/* If all outer actions are cleanups or must_not_throw,
we'll have no action record for it, since we had wanted
to encode these states in the call-site record directly.
Add a cleanup action to the chain to catch these. */
else if (next <= 0)
next = add_action_record (ar_hash, 0, 0);
return add_action_record (ar_hash, region->u.allowed.filter, next);
case ERT_MUST_NOT_THROW:
/* A must-not-throw region with no inner handlers or cleanups
requires no call-site entry. Note that this differs from
the no handler or cleanup case in that we do require an lsda
to be generated. Return a magic -2 value to record this. */
return -2;
}
gcc_unreachable ();
}
static int
add_call_site (rtx landing_pad, int action, int section)
{
call_site_record record;
record = ggc_alloc<call_site_record_d> ();
record->landing_pad = landing_pad;
record->action = action;
vec_safe_push (crtl->eh.call_site_record_v[section], record);
return call_site_base + crtl->eh.call_site_record_v[section]->length () - 1;
}
static rtx_note *
emit_note_eh_region_end (rtx_insn *insn)
{
return emit_note_after (NOTE_INSN_EH_REGION_END, insn);
}
/* Add NOP after NOTE_INSN_SWITCH_TEXT_SECTIONS when the cold section starts
with landing pad.
With landing pad being at offset 0 from the start label of the section
we would miss EH delivery because 0 is special and means no landing pad. */
static bool
maybe_add_nop_after_section_switch (void)
{
if (!crtl->uses_eh_lsda
|| !crtl->eh.call_site_record_v[1])
return false;
int n = vec_safe_length (crtl->eh.call_site_record_v[1]);
hash_set<rtx_insn *> visited;
for (int i = 0; i < n; ++i)
{
struct call_site_record_d *cs
= (*crtl->eh.call_site_record_v[1])[i];
if (cs->landing_pad)
{
rtx_insn *insn = as_a <rtx_insn *> (cs->landing_pad);
while (true)
{
/* Landing pads have LABEL_PRESERVE_P flag set. This check make
sure that we do not walk past landing pad visited earlier
which would result in possible quadratic behaviour. */
if (LABEL_P (insn) && LABEL_PRESERVE_P (insn)
&& visited.add (insn))
break;
/* Conservatively assume that ASM insn may be empty. We have
now way to tell what they contain. */
if (active_insn_p (insn)
&& GET_CODE (PATTERN (insn)) != ASM_INPUT
&& GET_CODE (PATTERN (insn)) != ASM_OPERANDS)
break;
/* If we reached the start of hot section, then NOP will be
needed. */
if (GET_CODE (insn) == NOTE
&& NOTE_KIND (insn) == NOTE_INSN_SWITCH_TEXT_SECTIONS)
{
emit_insn_after (gen_nop (), insn);
break;
}
/* We visit only labels from cold section. We should never hit
begining of the insn stream here. */
insn = PREV_INSN (insn);
}
}
}
return false;
}
/* Turn REG_EH_REGION notes back into NOTE_INSN_EH_REGION notes.
The new note numbers will not refer to region numbers, but
instead to call site entries. */
static unsigned int
convert_to_eh_region_ranges (void)
{
rtx insn;
rtx_insn *iter;
rtx_note *note;
action_hash_type ar_hash (31);
int last_action = -3;
rtx_insn *last_action_insn = NULL;
rtx last_landing_pad = NULL_RTX;
rtx_insn *first_no_action_insn = NULL;
int call_site = 0;
int cur_sec = 0;
rtx_insn *section_switch_note = NULL;
rtx_insn *first_no_action_insn_before_switch = NULL;
rtx_insn *last_no_action_insn_before_switch = NULL;
int saved_call_site_base = call_site_base;
vec_alloc (crtl->eh.action_record_data, 64);
for (iter = get_insns (); iter ; iter = NEXT_INSN (iter))
if (INSN_P (iter))
{
eh_landing_pad lp;
eh_region region;
bool nothrow;
int this_action;
rtx_code_label *this_landing_pad;
insn = iter;
if (NONJUMP_INSN_P (insn)
&& GET_CODE (PATTERN (insn)) == SEQUENCE)
insn = XVECEXP (PATTERN (insn), 0, 0);
nothrow = get_eh_region_and_lp_from_rtx (insn, &region, &lp);
if (nothrow)
continue;
if (region)
this_action = collect_one_action_chain (&ar_hash, region);
else
this_action = -1;
/* Existence of catch handlers, or must-not-throw regions
implies that an lsda is needed (even if empty). */
if (this_action != -1)
crtl->uses_eh_lsda = 1;
/* Delay creation of region notes for no-action regions
until we're sure that an lsda will be required. */
else if (last_action == -3)
{
first_no_action_insn = iter;
last_action = -1;
}
if (this_action >= 0)
this_landing_pad = lp->landing_pad;
else
this_landing_pad = NULL;
/* Differing actions or landing pads implies a change in call-site
info, which implies some EH_REGION note should be emitted. */
if (last_action != this_action
|| last_landing_pad != this_landing_pad)
{
/* If there is a queued no-action region in the other section
with hot/cold partitioning, emit it now. */
if (first_no_action_insn_before_switch)
{
gcc_assert (this_action != -1
&& last_action == (first_no_action_insn
? -1 : -3));
call_site = add_call_site (NULL_RTX, 0, 0);
note = emit_note_before (NOTE_INSN_EH_REGION_BEG,
first_no_action_insn_before_switch);
NOTE_EH_HANDLER (note) = call_site;
note
= emit_note_eh_region_end (last_no_action_insn_before_switch);
NOTE_EH_HANDLER (note) = call_site;
gcc_assert (last_action != -3
|| (last_action_insn
== last_no_action_insn_before_switch));
first_no_action_insn_before_switch = NULL;
last_no_action_insn_before_switch = NULL;
call_site_base++;
}
/* If we'd not seen a previous action (-3) or the previous
action was must-not-throw (-2), then we do not need an
end note. */
if (last_action >= -1)
{
/* If we delayed the creation of the begin, do it now. */
if (first_no_action_insn)
{
call_site = add_call_site (NULL_RTX, 0, cur_sec);
note = emit_note_before (NOTE_INSN_EH_REGION_BEG,
first_no_action_insn);
NOTE_EH_HANDLER (note) = call_site;
first_no_action_insn = NULL;
}
note = emit_note_eh_region_end (last_action_insn);
NOTE_EH_HANDLER (note) = call_site;
}
/* If the new action is must-not-throw, then no region notes
are created. */
if (this_action >= -1)
{
call_site = add_call_site (this_landing_pad,
this_action < 0 ? 0 : this_action,
cur_sec);
note = emit_note_before (NOTE_INSN_EH_REGION_BEG, iter);
NOTE_EH_HANDLER (note) = call_site;
}
last_action = this_action;
last_landing_pad = this_landing_pad;
}
last_action_insn = iter;
}
else if (NOTE_P (iter)
&& NOTE_KIND (iter) == NOTE_INSN_SWITCH_TEXT_SECTIONS)
{
gcc_assert (section_switch_note == NULL_RTX);
gcc_assert (flag_reorder_blocks_and_partition);
section_switch_note = iter;
if (first_no_action_insn)
{
first_no_action_insn_before_switch = first_no_action_insn;
last_no_action_insn_before_switch = last_action_insn;
first_no_action_insn = NULL;
gcc_assert (last_action == -1);
last_action = -3;
}
/* Force closing of current EH region before section switch and
opening a new one afterwards. */
else if (last_action != -3)
last_landing_pad = pc_rtx;
if (crtl->eh.call_site_record_v[cur_sec])
call_site_base += crtl->eh.call_site_record_v[cur_sec]->length ();
cur_sec++;
gcc_assert (crtl->eh.call_site_record_v[cur_sec] == NULL);
vec_alloc (crtl->eh.call_site_record_v[cur_sec], 10);
}
if (last_action >= -1 && ! first_no_action_insn)
{
note = emit_note_eh_region_end (last_action_insn);
NOTE_EH_HANDLER (note) = call_site;
}
call_site_base = saved_call_site_base;
return 0;
}
namespace {
const pass_data pass_data_convert_to_eh_region_ranges =
{
RTL_PASS, /* type */
"eh_ranges", /* name */
OPTGROUP_NONE, /* optinfo_flags */
TV_NONE, /* tv_id */
0, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
0, /* todo_flags_finish */
};
class pass_convert_to_eh_region_ranges : public rtl_opt_pass
{
public:
pass_convert_to_eh_region_ranges (gcc::context *ctxt)
: rtl_opt_pass (pass_data_convert_to_eh_region_ranges, ctxt)
{}
/* opt_pass methods: */
virtual bool gate (function *);
virtual unsigned int execute (function *)
{
int ret = convert_to_eh_region_ranges ();
maybe_add_nop_after_section_switch ();
return ret;
}
}; // class pass_convert_to_eh_region_ranges
bool
pass_convert_to_eh_region_ranges::gate (function *)
{
/* Nothing to do for SJLJ exceptions or if no regions created. */
if (cfun->eh->region_tree == NULL)
return false;
if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ)
return false;
return true;
}
} // anon namespace
rtl_opt_pass *
make_pass_convert_to_eh_region_ranges (gcc::context *ctxt)
{
return new pass_convert_to_eh_region_ranges (ctxt);
}
static void
push_uleb128 (vec<uchar, va_gc> **data_area, unsigned int value)
{
do
{
unsigned char byte = value & 0x7f;
value >>= 7;
if (value)
byte |= 0x80;
vec_safe_push (*data_area, byte);
}
while (value);
}
static void
push_sleb128 (vec<uchar, va_gc> **data_area, int value)
{
unsigned char byte;
int more;
do
{
byte = value & 0x7f;
value >>= 7;
more = ! ((value == 0 && (byte & 0x40) == 0)
|| (value == -1 && (byte & 0x40) != 0));
if (more)
byte |= 0x80;
vec_safe_push (*data_area, byte);
}
while (more);
}
static int
dw2_size_of_call_site_table (int section)
{
int n = vec_safe_length (crtl->eh.call_site_record_v[section]);
int size = n * (4 + 4 + 4);
int i;
for (i = 0; i < n; ++i)
{
struct call_site_record_d *cs =
(*crtl->eh.call_site_record_v[section])[i];
size += size_of_uleb128 (cs->action);
}
return size;
}
static int
sjlj_size_of_call_site_table (void)
{
int n = vec_safe_length (crtl->eh.call_site_record_v[0]);
int size = 0;
int i;
for (i = 0; i < n; ++i)
{
struct call_site_record_d *cs =
(*crtl->eh.call_site_record_v[0])[i];
size += size_of_uleb128 (INTVAL (cs->landing_pad));
size += size_of_uleb128 (cs->action);
}
return size;
}
static void
dw2_output_call_site_table (int cs_format, int section)
{
int n = vec_safe_length (crtl->eh.call_site_record_v[section]);
int i;
const char *begin;
if (section == 0)
begin = current_function_func_begin_label;
else if (first_function_block_is_cold)
begin = crtl->subsections.hot_section_label;
else
begin = crtl->subsections.cold_section_label;
for (i = 0; i < n; ++i)
{
struct call_site_record_d *cs = (*crtl->eh.call_site_record_v[section])[i];
char reg_start_lab[32];
char reg_end_lab[32];
char landing_pad_lab[32];
ASM_GENERATE_INTERNAL_LABEL (reg_start_lab, "LEHB", call_site_base + i);
ASM_GENERATE_INTERNAL_LABEL (reg_end_lab, "LEHE", call_site_base + i);
if (cs->landing_pad)
ASM_GENERATE_INTERNAL_LABEL (landing_pad_lab, "L",
CODE_LABEL_NUMBER (cs->landing_pad));
/* ??? Perhaps use insn length scaling if the assembler supports
generic arithmetic. */
/* ??? Perhaps use attr_length to choose data1 or data2 instead of
data4 if the function is small enough. */
if (cs_format == DW_EH_PE_uleb128)
{
dw2_asm_output_delta_uleb128 (reg_start_lab, begin,
"region %d start", i);
dw2_asm_output_delta_uleb128 (reg_end_lab, reg_start_lab,
"length");
if (cs->landing_pad)
dw2_asm_output_delta_uleb128 (landing_pad_lab, begin,
"landing pad");
else
dw2_asm_output_data_uleb128 (0, "landing pad");
}
else
{
dw2_asm_output_delta (4, reg_start_lab, begin,
"region %d start", i);
dw2_asm_output_delta (4, reg_end_lab, reg_start_lab, "length");
if (cs->landing_pad)
dw2_asm_output_delta (4, landing_pad_lab, begin,
"landing pad");
else
dw2_asm_output_data (4, 0, "landing pad");
}
dw2_asm_output_data_uleb128 (cs->action, "action");
}
call_site_base += n;
}
static void
sjlj_output_call_site_table (void)
{
int n = vec_safe_length (crtl->eh.call_site_record_v[0]);
int i;
for (i = 0; i < n; ++i)
{
struct call_site_record_d *cs = (*crtl->eh.call_site_record_v[0])[i];
dw2_asm_output_data_uleb128 (INTVAL (cs->landing_pad),
"region %d landing pad", i);
dw2_asm_output_data_uleb128 (cs->action, "action");
}
call_site_base += n;
}
/* Switch to the section that should be used for exception tables. */
static void
switch_to_exception_section (const char * ARG_UNUSED (fnname))
{
section *s;
if (exception_section)
s = exception_section;
else
{
int flags;
if (EH_TABLES_CAN_BE_READ_ONLY)
{
int tt_format =
ASM_PREFERRED_EH_DATA_FORMAT (/*code=*/0, /*global=*/1);
flags = ((! flag_pic
|| ((tt_format & 0x70) != DW_EH_PE_absptr
&& (tt_format & 0x70) != DW_EH_PE_aligned))
? 0 : SECTION_WRITE);
}
else
flags = SECTION_WRITE;
/* Compute the section and cache it into exception_section,
unless it depends on the function name. */
if (targetm_common.have_named_sections)
{
#ifdef HAVE_LD_EH_GC_SECTIONS
if (flag_function_sections
|| (DECL_COMDAT_GROUP (current_function_decl) && HAVE_COMDAT_GROUP))
{
char *section_name = XNEWVEC (char, strlen (fnname) + 32);
/* The EH table must match the code section, so only mark
it linkonce if we have COMDAT groups to tie them together. */
if (DECL_COMDAT_GROUP (current_function_decl) && HAVE_COMDAT_GROUP)
flags |= SECTION_LINKONCE;
sprintf