blob: 9ebe6705e0f629f1958458dcceac461199b9e210 [file] [log] [blame]
/* Expands front end tree to back end RTL for GNU C-Compiler
Copyright (C) 1987, 88, 89, 92-97, 1998 Free Software Foundation, Inc.
This file is part of GNU CC.
GNU CC 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 2, or (at your option)
any later version.
GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* This file handles the generation of rtl code from tree structure
above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
It also creates the rtl expressions for parameters and auto variables
and has full responsibility for allocating stack slots.
The functions whose names start with `expand_' are called by the
parser to generate RTL instructions for various kinds of constructs.
Some control and binding constructs require calling several such
functions at different times. For example, a simple if-then
is expanded by calling `expand_start_cond' (with the condition-expression
as argument) before parsing the then-clause and calling `expand_end_cond'
after parsing the then-clause. */
#include "config.h"
#include "system.h"
#include "rtl.h"
#include "tree.h"
#include "flags.h"
#include "except.h"
#include "function.h"
#include "insn-flags.h"
#include "insn-config.h"
#include "insn-codes.h"
#include "expr.h"
#include "hard-reg-set.h"
#include "obstack.h"
#include "loop.h"
#include "recog.h"
#include "machmode.h"
#include "toplev.h"
#include "output.h"
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free
struct obstack stmt_obstack;
/* Assume that case vectors are not pc-relative. */
/* Filename and line number of last line-number note,
whether we actually emitted it or not. */
char *emit_filename;
int emit_lineno;
/* Nonzero if within a ({...}) grouping, in which case we must
always compute a value for each expr-stmt in case it is the last one. */
int expr_stmts_for_value;
/* Each time we expand an expression-statement,
record the expr's type and its RTL value here. */
static tree last_expr_type;
static rtx last_expr_value;
/* Each time we expand the end of a binding contour (in `expand_end_bindings')
and we emit a new NOTE_INSN_BLOCK_END note, we save a pointer to it here.
This is used by the `remember_end_note' function to record the endpoint
of each generated block in its associated BLOCK node. */
static rtx last_block_end_note;
/* Number of binding contours started so far in this function. */
int block_start_count;
/* Nonzero if function being compiled needs to
return the address of where it has put a structure value. */
extern int current_function_returns_pcc_struct;
/* Label that will go on parm cleanup code, if any.
Jumping to this label runs cleanup code for parameters, if
such code must be run. Following this code is the logical return label. */
extern rtx cleanup_label;
/* Label that will go on function epilogue.
Jumping to this label serves as a "return" instruction
on machines which require execution of the epilogue on all returns. */
extern rtx return_label;
/* Offset to end of allocated area of stack frame.
If stack grows down, this is the address of the last stack slot allocated.
If stack grows up, this is the address for the next slot. */
extern int frame_offset;
/* Label to jump back to for tail recursion, or 0 if we have
not yet needed one for this function. */
extern rtx tail_recursion_label;
/* Place after which to insert the tail_recursion_label if we need one. */
extern rtx tail_recursion_reentry;
/* Location at which to save the argument pointer if it will need to be
referenced. There are two cases where this is done: if nonlocal gotos
exist, or if vars whose is an offset from the argument pointer will be
needed by inner routines. */
extern rtx arg_pointer_save_area;
/* Chain of all RTL_EXPRs that have insns in them. */
extern tree rtl_expr_chain;
/* Functions and data structures for expanding case statements. */
/* Case label structure, used to hold info on labels within case
statements. We handle "range" labels; for a single-value label
as in C, the high and low limits are the same.
An AVL tree of case nodes is initially created, and later transformed
to a list linked via the RIGHT fields in the nodes. Nodes with
higher case values are later in the list.
Switch statements can be output in one of two forms. A branch table
is used if there are more than a few labels and the labels are dense
within the range between the smallest and largest case value. If a
branch table is used, no further manipulations are done with the case
node chain.
The alternative to the use of a branch table is to generate a series
of compare and jump insns. When that is done, we use the LEFT, RIGHT,
and PARENT fields to hold a binary tree. Initially the tree is
totally unbalanced, with everything on the right. We balance the tree
with nodes on the left having lower case values than the parent
and nodes on the right having higher values. We then output the tree
in order. */
struct case_node
struct case_node *left; /* Left son in binary tree */
struct case_node *right; /* Right son in binary tree; also node chain */
struct case_node *parent; /* Parent of node in binary tree */
tree low; /* Lowest index value for this label */
tree high; /* Highest index value for this label */
tree code_label; /* Label to jump to when node matches */
int balance;
typedef struct case_node case_node;
typedef struct case_node *case_node_ptr;
/* These are used by estimate_case_costs and balance_case_nodes. */
/* This must be a signed type, and non-ANSI compilers lack signed char. */
static short *cost_table;
static int use_cost_table;
/* Stack of control and binding constructs we are currently inside.
These constructs begin when you call `expand_start_WHATEVER'
and end when you call `expand_end_WHATEVER'. This stack records
info about how the construct began that tells the end-function
what to do. It also may provide information about the construct
to alter the behavior of other constructs within the body.
For example, they may affect the behavior of C `break' and `continue'.
Each construct gets one `struct nesting' object.
All of these objects are chained through the `all' field.
`nesting_stack' points to the first object (innermost construct).
The position of an entry on `nesting_stack' is in its `depth' field.
Each type of construct has its own individual stack.
For example, loops have `loop_stack'. Each object points to the
next object of the same type through the `next' field.
Some constructs are visible to `break' exit-statements and others
are not. Which constructs are visible depends on the language.
Therefore, the data structure allows each construct to be visible
or not, according to the args given when the construct is started.
The construct is visible if the `exit_label' field is non-null.
In that case, the value should be a CODE_LABEL rtx. */
struct nesting
struct nesting *all;
struct nesting *next;
int depth;
rtx exit_label;
/* For conds (if-then and if-then-else statements). */
/* Label for the end of the if construct.
There is none if EXITFLAG was not set
and no `else' has been seen yet. */
rtx endif_label;
/* Label for the end of this alternative.
This may be the end of the if or the next else/elseif. */
rtx next_label;
} cond;
/* For loops. */
/* Label at the top of the loop; place to loop back to. */
rtx start_label;
/* Label at the end of the whole construct. */
rtx end_label;
/* Label before a jump that branches to the end of the whole
construct. This is where destructors go if any. */
rtx alt_end_label;
/* Label for `continue' statement to jump to;
this is in front of the stepper of the loop. */
rtx continue_label;
} loop;
/* For variable binding contours. */
/* Sequence number of this binding contour within the function,
in order of entry. */
int block_start_count;
/* Nonzero => value to restore stack to on exit. */
rtx stack_level;
/* The NOTE that starts this contour.
Used by expand_goto to check whether the destination
is within each contour or not. */
rtx first_insn;
/* Innermost containing binding contour that has a stack level. */
struct nesting *innermost_stack_block;
/* List of cleanups to be run on exit from this contour.
This is a list of expressions to be evaluated.
The TREE_PURPOSE of each link is the ..._DECL node
which the cleanup pertains to. */
tree cleanups;
/* List of cleanup-lists of blocks containing this block,
as they were at the locus where this block appears.
There is an element for each containing block,
ordered innermost containing block first.
The tail of this list can be 0,
if all remaining elements would be empty lists.
The element's TREE_VALUE is the cleanup-list of that block,
which may be null. */
tree outer_cleanups;
/* Chain of labels defined inside this binding contour.
For contours that have stack levels or cleanups. */
struct label_chain *label_chain;
/* Number of function calls seen, as of start of this block. */
int function_call_count;
/* Nonzero if this is associated with a EH region. */
int exception_region;
/* The saved target_temp_slot_level from our outer block.
We may reset target_temp_slot_level to be the level of
this block, if that is done, target_temp_slot_level
reverts to the saved target_temp_slot_level at the very
end of the block. */
int target_temp_slot_level;
/* True if we are currently emitting insns in an area of
output code that is controlled by a conditional
expression. This is used by the cleanup handling code to
generate conditional cleanup actions. */
int conditional_code;
/* A place to move the start of the exception region for any
of the conditional cleanups, must be at the end or after
the start of the last unconditional cleanup, and before any
conditional branch points. */
rtx last_unconditional_cleanup;
/* When in a conditional context, this is the specific
cleanup list associated with last_unconditional_cleanup,
where we place the conditionalized cleanups. */
tree *cleanup_ptr;
} block;
/* For switch (C) or case (Pascal) statements,
and also for dummies (see `expand_start_case_dummy'). */
/* The insn after which the case dispatch should finally
be emitted. Zero for a dummy. */
rtx start;
/* A list of case labels; it is first built as an AVL tree.
During expand_end_case, this is converted to a list, and may be
rearranged into a nearly balanced binary tree. */
struct case_node *case_list;
/* Label to jump to if no case matches. */
tree default_label;
/* The expression to be dispatched on. */
tree index_expr;
/* Type that INDEX_EXPR should be converted to. */
tree nominal_type;
/* Number of range exprs in case statement. */
int num_ranges;
/* Name of this kind of statement, for warnings. */
char *printname;
/* Used to save no_line_numbers till we see the first case label.
We set this to -1 when we see the first case label in this
case statement. */
int line_number_status;
} case_stmt;
} data;
/* Chain of all pending binding contours. */
struct nesting *block_stack;
/* If any new stacks are added here, add them to POPSTACKS too. */
/* Chain of all pending binding contours that restore stack levels
or have cleanups. */
struct nesting *stack_block_stack;
/* Chain of all pending conditional statements. */
struct nesting *cond_stack;
/* Chain of all pending loops. */
struct nesting *loop_stack;
/* Chain of all pending case or switch statements. */
struct nesting *case_stack;
/* Separate chain including all of the above,
chained through the `all' field. */
struct nesting *nesting_stack;
/* Number of entries on nesting_stack now. */
int nesting_depth;
/* Allocate and return a new `struct nesting'. */
#define ALLOC_NESTING() \
(struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
/* Pop the nesting stack element by element until we pop off
the element which is at the top of STACK.
Update all the other stacks, popping off elements from them
as we pop them from nesting_stack. */
do { struct nesting *target = STACK; \
struct nesting *this; \
do { this = nesting_stack; \
if (loop_stack == this) \
loop_stack = loop_stack->next; \
if (cond_stack == this) \
cond_stack = cond_stack->next; \
if (block_stack == this) \
block_stack = block_stack->next; \
if (stack_block_stack == this) \
stack_block_stack = stack_block_stack->next; \
if (case_stack == this) \
case_stack = case_stack->next; \
nesting_depth = nesting_stack->depth - 1; \
nesting_stack = this->all; \
obstack_free (&stmt_obstack, this); } \
while (this != target); } while (0)
/* In some cases it is impossible to generate code for a forward goto
until the label definition is seen. This happens when it may be necessary
for the goto to reset the stack pointer: we don't yet know how to do that.
So expand_goto puts an entry on this fixup list.
Each time a binding contour that resets the stack is exited,
we check each fixup.
If the target label has now been defined, we can insert the proper code. */
struct goto_fixup
/* Points to following fixup. */
struct goto_fixup *next;
/* Points to the insn before the jump insn.
If more code must be inserted, it goes after this insn. */
rtx before_jump;
/* The LABEL_DECL that this jump is jumping to, or 0
for break, continue or return. */
tree target;
/* The BLOCK for the place where this goto was found. */
tree context;
/* The CODE_LABEL rtx that this is jumping to. */
rtx target_rtl;
/* Number of binding contours started in current function
before the label reference. */
int block_start_count;
/* The outermost stack level that should be restored for this jump.
Each time a binding contour that resets the stack is exited,
if the target label is *not* yet defined, this slot is updated. */
rtx stack_level;
/* List of lists of cleanup expressions to be run by this goto.
There is one element for each block that this goto is within.
The tail of this list can be 0,
if all remaining elements would be empty.
The TREE_VALUE contains the cleanup list of that block as of the
time this goto was seen.
The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
tree cleanup_list_list;
static struct goto_fixup *goto_fixup_chain;
/* Within any binding contour that must restore a stack level,
all labels are recorded with a chain of these structures. */
struct label_chain
/* Points to following fixup. */
struct label_chain *next;
tree label;
/* Non-zero if we are using EH to handle cleanus. */
static int using_eh_for_cleanups_p = 0;
static void expand_goto_internal PROTO((tree, rtx, rtx));
static int expand_fixup PROTO((tree, rtx, rtx));
static void fixup_gotos PROTO((struct nesting *, rtx, tree,
rtx, int));
static void expand_null_return_1 PROTO((rtx, int));
static void expand_value_return PROTO((rtx));
static int tail_recursion_args PROTO((tree, tree));
static void expand_cleanups PROTO((tree, tree, int, int));
static void check_seenlabel PROTO((void));
static void do_jump_if_equal PROTO((rtx, rtx, rtx, int));
static int estimate_case_costs PROTO((case_node_ptr));
static void group_case_nodes PROTO((case_node_ptr));
static void balance_case_nodes PROTO((case_node_ptr *,
static int node_has_low_bound PROTO((case_node_ptr, tree));
static int node_has_high_bound PROTO((case_node_ptr, tree));
static int node_is_bounded PROTO((case_node_ptr, tree));
static void emit_jump_if_reachable PROTO((rtx));
static void emit_case_nodes PROTO((rtx, case_node_ptr, rtx, tree));
static int add_case_node PROTO((tree, tree, tree, tree *));
static struct case_node *case_tree2list PROTO((case_node *, case_node *));
using_eh_for_cleanups ()
using_eh_for_cleanups_p = 1;
init_stmt ()
gcc_obstack_init (&stmt_obstack);
init_eh ();
init_stmt_for_function ()
/* We are not currently within any block, conditional, loop or case. */
block_stack = 0;
stack_block_stack = 0;
loop_stack = 0;
case_stack = 0;
cond_stack = 0;
nesting_stack = 0;
nesting_depth = 0;
block_start_count = 0;
/* No gotos have been expanded yet. */
goto_fixup_chain = 0;
/* We are not processing a ({...}) grouping. */
expr_stmts_for_value = 0;
last_expr_type = 0;
init_eh_for_function ();
save_stmt_status (p)
struct function *p;
p->block_stack = block_stack;
p->stack_block_stack = stack_block_stack;
p->cond_stack = cond_stack;
p->loop_stack = loop_stack;
p->case_stack = case_stack;
p->nesting_stack = nesting_stack;
p->nesting_depth = nesting_depth;
p->block_start_count = block_start_count;
p->last_expr_type = last_expr_type;
p->last_expr_value = last_expr_value;
p->expr_stmts_for_value = expr_stmts_for_value;
p->emit_filename = emit_filename;
p->emit_lineno = emit_lineno;
p->goto_fixup_chain = goto_fixup_chain;
save_eh_status (p);
restore_stmt_status (p)
struct function *p;
block_stack = p->block_stack;
stack_block_stack = p->stack_block_stack;
cond_stack = p->cond_stack;
loop_stack = p->loop_stack;
case_stack = p->case_stack;
nesting_stack = p->nesting_stack;
nesting_depth = p->nesting_depth;
block_start_count = p->block_start_count;
last_expr_type = p->last_expr_type;
last_expr_value = p->last_expr_value;
expr_stmts_for_value = p->expr_stmts_for_value;
emit_filename = p->emit_filename;
emit_lineno = p->emit_lineno;
goto_fixup_chain = p->goto_fixup_chain;
restore_eh_status (p);
/* Emit a no-op instruction. */
emit_nop ()
rtx last_insn;
last_insn = get_last_insn ();
if (!optimize
&& (GET_CODE (last_insn) == CODE_LABEL
|| (GET_CODE (last_insn) == NOTE
&& prev_real_insn (last_insn) == 0)))
emit_insn (gen_nop ());
/* Return the rtx-label that corresponds to a LABEL_DECL,
creating it if necessary. */
label_rtx (label)
tree label;
if (TREE_CODE (label) != LABEL_DECL)
abort ();
if (DECL_RTL (label))
return DECL_RTL (label);
return DECL_RTL (label) = gen_label_rtx ();
/* Add an unconditional jump to LABEL as the next sequential instruction. */
emit_jump (label)
rtx label;
do_pending_stack_adjust ();
emit_jump_insn (gen_jump (label));
emit_barrier ();
/* Emit code to jump to the address
specified by the pointer expression EXP. */
expand_computed_goto (exp)
tree exp;
rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
x = convert_memory_address (Pmode, x);
emit_queue ();
/* Be sure the function is executable. */
if (flag_check_memory_usage)
emit_library_call (chkr_check_exec_libfunc, 1,
VOIDmode, 1, x, ptr_mode);
do_pending_stack_adjust ();
emit_indirect_jump (x);
/* Handle goto statements and the labels that they can go to. */
/* Specify the location in the RTL code of a label LABEL,
which is a LABEL_DECL tree node.
This is used for the kind of label that the user can jump to with a
goto statement, and for alternatives of a switch or case statement.
RTL labels generated for loops and conditionals don't go through here;
they are generated directly at the RTL level, by other functions below.
Note that this has nothing to do with defining label *names*.
Languages vary in how they do that and what that even means. */
expand_label (label)
tree label;
struct label_chain *p;
do_pending_stack_adjust ();
emit_label (label_rtx (label));
if (DECL_NAME (label))
if (stack_block_stack != 0)
p = (struct label_chain *) oballoc (sizeof (struct label_chain));
p->next = stack_block_stack->data.block.label_chain;
stack_block_stack->data.block.label_chain = p;
p->label = label;
/* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
from nested functions. */
declare_nonlocal_label (label)
tree label;
nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
LABEL_PRESERVE_P (label_rtx (label)) = 1;
if (nonlocal_goto_handler_slot == 0)
= assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
emit_stack_save (SAVE_NONLOCAL,
PREV_INSN (tail_recursion_reentry));
/* Generate RTL code for a `goto' statement with target label LABEL.
LABEL should be a LABEL_DECL tree node that was or will later be
defined with `expand_label'. */
expand_goto (label)
tree label;
tree context;
/* Check for a nonlocal goto to a containing function. */
context = decl_function_context (label);
if (context != 0 && context != current_function_decl)
struct function *p = find_function_data (context);
rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
rtx temp;
p->has_nonlocal_label = 1;
current_function_has_nonlocal_goto = 1;
LABEL_REF_NONLOCAL_P (label_ref) = 1;
/* Copy the rtl for the slots so that they won't be shared in
case the virtual stack vars register gets instantiated differently
in the parent than in the child. */
#if HAVE_nonlocal_goto
if (HAVE_nonlocal_goto)
emit_insn (gen_nonlocal_goto (lookup_static_chain (label),
copy_rtx (p->nonlocal_goto_handler_slot),
copy_rtx (p->nonlocal_goto_stack_level),
rtx addr;
/* Restore frame pointer for containing function.
This sets the actual hard register used for the frame pointer
to the location of the function's incoming static chain info.
The non-local goto handler will then adjust it to contain the
proper value and reload the argument pointer, if needed. */
emit_move_insn (hard_frame_pointer_rtx, lookup_static_chain (label));
/* We have now loaded the frame pointer hardware register with
the address of that corresponds to the start of the virtual
stack vars. So replace virtual_stack_vars_rtx in all
addresses we use with stack_pointer_rtx. */
/* Get addr of containing function's current nonlocal goto handler,
which will do any cleanups and then jump to the label. */
addr = copy_rtx (p->nonlocal_goto_handler_slot);
temp = copy_to_reg (replace_rtx (addr, virtual_stack_vars_rtx,
/* Restore the stack pointer. Note this uses fp just restored. */
addr = p->nonlocal_goto_stack_level;
if (addr)
addr = replace_rtx (copy_rtx (addr),
emit_stack_restore (SAVE_NONLOCAL, addr, NULL_RTX);
/* Put in the static chain register the nonlocal label address. */
emit_move_insn (static_chain_rtx, label_ref);
/* USE of hard_frame_pointer_rtx added for consistency; not clear if
really needed. */
emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
emit_insn (gen_rtx_USE (VOIDmode, static_chain_rtx));
emit_indirect_jump (temp);
expand_goto_internal (label, label_rtx (label), NULL_RTX);
/* Generate RTL code for a `goto' statement with target label BODY.
LABEL should be a LABEL_REF.
LAST_INSN, if non-0, is the rtx we should consider as the last
insn emitted (for the purposes of cleaning up a return). */
static void
expand_goto_internal (body, label, last_insn)
tree body;
rtx label;
rtx last_insn;
struct nesting *block;
rtx stack_level = 0;
if (GET_CODE (label) != CODE_LABEL)
abort ();
/* If label has already been defined, we can tell now
whether and how we must alter the stack level. */
if (PREV_INSN (label) != 0)
/* Find the innermost pending block that contains the label.
(Check containment by comparing insn-uids.)
Then restore the outermost stack level within that block,
and do cleanups of all blocks contained in it. */
for (block = block_stack; block; block = block->next)
if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
if (block->data.block.stack_level != 0)
stack_level = block->data.block.stack_level;
/* Execute the cleanups for blocks we are exiting. */
if (block->data.block.cleanups != 0)
expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
do_pending_stack_adjust ();
if (stack_level)
/* Ensure stack adjust isn't done by emit_jump, as this
would clobber the stack pointer. This one should be
deleted as dead by flow. */
clear_pending_stack_adjust ();
do_pending_stack_adjust ();
emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
if (body != 0 && DECL_TOO_LATE (body))
error ("jump to `%s' invalidly jumps into binding contour",
/* Label not yet defined: may need to put this goto
on the fixup list. */
else if (! expand_fixup (body, label, last_insn))
/* No fixup needed. Record that the label is the target
of at least one goto that has no fixup. */
if (body != 0)
emit_jump (label);
/* Generate if necessary a fixup for a goto
whose target label in tree structure (if any) is TREE_LABEL
and whose target in rtl is RTL_LABEL.
If LAST_INSN is nonzero, we pretend that the jump appears
after insn LAST_INSN instead of at the current point in the insn stream.
The fixup will be used later to insert insns just before the goto.
Those insns will restore the stack level as appropriate for the
target label, and will (in the case of C++) also invoke any object
destructors which have to be invoked when we exit the scopes which
are exited by the goto.
Value is nonzero if a fixup is made. */
static int
expand_fixup (tree_label, rtl_label, last_insn)
tree tree_label;
rtx rtl_label;
rtx last_insn;
struct nesting *block, *end_block;
/* See if we can recognize which block the label will be output in.
This is possible in some very common cases.
If we succeed, set END_BLOCK to that block.
Otherwise, set it to 0. */
if (cond_stack
&& (rtl_label == cond_stack->data.cond.endif_label
|| rtl_label == cond_stack->data.cond.next_label))
end_block = cond_stack;
/* If we are in a loop, recognize certain labels which
are likely targets. This reduces the number of fixups
we need to create. */
else if (loop_stack
&& (rtl_label == loop_stack->data.loop.start_label
|| rtl_label == loop_stack->data.loop.end_label
|| rtl_label == loop_stack->data.loop.continue_label))
end_block = loop_stack;
end_block = 0;
/* Now set END_BLOCK to the binding level to which we will return. */
if (end_block)
struct nesting *next_block = end_block->all;
block = block_stack;
/* First see if the END_BLOCK is inside the innermost binding level.
If so, then no cleanups or stack levels are relevant. */
while (next_block && next_block != block)
next_block = next_block->all;
if (next_block)
return 0;
/* Otherwise, set END_BLOCK to the innermost binding level
which is outside the relevant control-structure nesting. */
next_block = block_stack->next;
for (block = block_stack; block != end_block; block = block->all)
if (block == next_block)
next_block = next_block->next;
end_block = next_block;
/* Does any containing block have a stack level or cleanups?
If not, no fixup is needed, and that is the normal case
(the only case, for standard C). */
for (block = block_stack; block != end_block; block = block->next)
if (block->data.block.stack_level != 0
|| block->data.block.cleanups != 0)
if (block != end_block)
/* Ok, a fixup is needed. Add a fixup to the list of such. */
struct goto_fixup *fixup
= (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
/* In case an old stack level is restored, make sure that comes
after any pending stack adjust. */
/* ?? If the fixup isn't to come at the present position,
doing the stack adjust here isn't useful. Doing it with our
settings at that location isn't useful either. Let's hope
someone does it! */
if (last_insn == 0)
do_pending_stack_adjust ();
fixup->target = tree_label;
fixup->target_rtl = rtl_label;
/* Create a BLOCK node and a corresponding matched set of
this point. The notes will encapsulate any and all fixup
code which we might later insert at this point in the insn
stream. Also, the BLOCK node will be the parent (i.e. the
`SUPERBLOCK') of any other BLOCK nodes which we might create
later on when we are expanding the fixup code. */
register rtx original_before_jump
= last_insn ? last_insn : get_last_insn ();
start_sequence ();
pushlevel (0);
fixup->before_jump = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
fixup->context = poplevel (1, 0, 0); /* Create the BLOCK node now! */
end_sequence ();
emit_insns_after (fixup->before_jump, original_before_jump);
fixup->block_start_count = block_start_count;
fixup->stack_level = 0;
= ((block->data.block.outer_cleanups
|| block->data.block.cleanups)
? tree_cons (NULL_TREE, block->data.block.cleanups,
: 0);
fixup->next = goto_fixup_chain;
goto_fixup_chain = fixup;
return block != 0;
/* Expand any needed fixups in the outputmost binding level of the
function. FIRST_INSN is the first insn in the function. */
expand_fixups (first_insn)
rtx first_insn;
fixup_gotos (NULL_PTR, NULL_RTX, NULL_TREE, first_insn, 0);
/* When exiting a binding contour, process all pending gotos requiring fixups.
THISBLOCK is the structure that describes the block being exited.
STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
FIRST_INSN is the insn that began this contour.
Gotos that jump out of this contour must restore the
stack level and do the cleanups before actually jumping.
DONT_JUMP_IN nonzero means report error there is a jump into this
contour from before the beginning of the contour.
This is also done if STACK_LEVEL is nonzero. */
static void
fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
struct nesting *thisblock;
rtx stack_level;
tree cleanup_list;
rtx first_insn;
int dont_jump_in;
register struct goto_fixup *f, *prev;
/* F is the fixup we are considering; PREV is the previous one. */
/* We run this loop in two passes so that cleanups of exited blocks
are run first, and blocks that are exited are marked so
afterwards. */
for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
/* Test for a fixup that is inactive because it is already handled. */
if (f->before_jump == 0)
/* Delete inactive fixup from the chain, if that is easy to do. */
if (prev != 0)
prev->next = f->next;
/* Has this fixup's target label been defined?
If so, we can finalize it. */
else if (PREV_INSN (f->target_rtl) != 0)
register rtx cleanup_insns;
/* Get the first non-label after the label
this goto jumps to. If that's before this scope begins,
we don't have a jump into the scope. */
rtx after_label = f->target_rtl;
while (after_label != 0 && GET_CODE (after_label) == CODE_LABEL)
after_label = NEXT_INSN (after_label);
/* If this fixup jumped into this contour from before the beginning
of this contour, report an error. */
/* ??? Bug: this does not detect jumping in through intermediate
blocks that have stack levels or cleanups.
It detects only a problem with the innermost block
around the label. */
if (f->target != 0
&& (dont_jump_in || stack_level || cleanup_list)
/* If AFTER_LABEL is 0, it means the jump goes to the end
of the rtl, which means it jumps into this scope. */
&& (after_label == 0
|| INSN_UID (first_insn) < INSN_UID (after_label))
&& INSN_UID (first_insn) > INSN_UID (f->before_jump)
&& ! DECL_ERROR_ISSUED (f->target))
error_with_decl (f->target,
"label `%s' used before containing binding contour");
/* Prevent multiple errors for one label. */
DECL_ERROR_ISSUED (f->target) = 1;
/* We will expand the cleanups into a sequence of their own and
then later on we will attach this new sequence to the insn
stream just ahead of the actual jump insn. */
start_sequence ();
/* Temporarily restore the lexical context where we will
logically be inserting the fixup code. We do this for the
sake of getting the debugging information right. */
pushlevel (0);
set_block (f->context);
/* Expand the cleanups for blocks this jump exits. */
if (f->cleanup_list_list)
tree lists;
for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
/* Marked elements correspond to blocks that have been closed.
Do their cleanups. */
&& TREE_VALUE (lists) != 0)
expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
/* Pop any pushes done in the cleanups,
in case function is about to return. */
do_pending_stack_adjust ();
/* Restore stack level for the biggest contour that this
jump jumps out of. */
if (f->stack_level)
emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
/* Finish up the sequence containing the insns which implement the
necessary cleanups, and then attach that whole sequence to the
insn stream just ahead of the actual jump insn. Attaching it
at that point insures that any cleanups which are in fact
implicit C++ object destructions (which must be executed upon
leaving the block) appear (to the debugger) to be taking place
in an area of the generated code where the object(s) being
destructed are still "in scope". */
cleanup_insns = get_insns ();
poplevel (1, 0, 0);
end_sequence ();
emit_insns_after (cleanup_insns, f->before_jump);
f->before_jump = 0;
/* For any still-undefined labels, do the cleanups for this block now.
We must do this now since items in the cleanup list may go out
of scope when the block ends. */
for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
if (f->before_jump != 0
&& PREV_INSN (f->target_rtl) == 0
/* Label has still not appeared. If we are exiting a block with
a stack level to restore, that started before the fixup,
mark this stack level as needing restoration
when the fixup is later finalized. */
&& thisblock != 0
/* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
means the label is undefined. That's erroneous, but possible. */
&& (thisblock->data.block.block_start_count
<= f->block_start_count))
tree lists = f->cleanup_list_list;
rtx cleanup_insns;
for (; lists; lists = TREE_CHAIN (lists))
/* If the following elt. corresponds to our containing block
then the elt. must be for this block. */
if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
start_sequence ();
pushlevel (0);
set_block (f->context);
expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
do_pending_stack_adjust ();
cleanup_insns = get_insns ();
poplevel (1, 0, 0);
end_sequence ();
if (cleanup_insns != 0)
= emit_insns_after (cleanup_insns, f->before_jump);
f->cleanup_list_list = TREE_CHAIN (lists);
if (stack_level)
f->stack_level = stack_level;
/* Generate RTL for an asm statement (explicit assembler code).
BODY is a STRING_CST node containing the assembler code text,
or an ADDR_EXPR containing a STRING_CST. */
expand_asm (body)
tree body;
if (flag_check_memory_usage)
error ("`asm' cannot be used with `-fcheck-memory-usage'");
if (TREE_CODE (body) == ADDR_EXPR)
body = TREE_OPERAND (body, 0);
emit_insn (gen_rtx_ASM_INPUT (VOIDmode,
last_expr_type = 0;
/* Generate RTL for an asm statement with arguments.
STRING is the instruction template.
OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
Each output or input has an expression in the TREE_VALUE and
a constraint-string in the TREE_PURPOSE.
CLOBBERS is a list of STRING_CST nodes each naming a hard register
that is clobbered by this insn.
Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
Some elements of OUTPUTS may be replaced with trees representing temporary
values. The caller should copy those temporary values to the originally
specified lvalues.
VOL nonzero means the insn is volatile; don't optimize it. */
expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
tree string, outputs, inputs, clobbers;
int vol;
char *filename;
int line;
rtvec argvec, constraints;
rtx body;
int ninputs = list_length (inputs);
int noutputs = list_length (outputs);
int ninout = 0;
int nclobbers;
tree tail;
register int i;
/* Vector of RTX's of evaluated output operands. */
rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
enum machine_mode *inout_mode
= (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
/* The insn we have emitted. */
rtx insn;
/* An ASM with no outputs needs to be treated as volatile, for now. */
if (noutputs == 0)
vol = 1;
if (flag_check_memory_usage)
error ("`asm' cannot be used with `-fcheck-memory-usage'");
/* Count the number of meaningful clobbered registers, ignoring what
we would ignore later. */
nclobbers = 0;
for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
i = decode_reg_name (regname);
if (i >= 0 || i == -4)
else if (i == -2)
error ("unknown register name `%s' in `asm'", regname);
last_expr_type = 0;
for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
tree val = TREE_VALUE (tail);
tree type = TREE_TYPE (val);
int j;
int found_equal = 0;
int found_plus = 0;
int allows_reg = 0;
/* If there's an erroneous arg, emit no insn. */
if (TREE_TYPE (val) == error_mark_node)
/* Make sure constraint has `=' and does not have `+'. Also, see
if it allows any register. Be liberal on the latter test, since
the worst that happens if we get it wrong is we issue an error
message. */
for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)) - 1; j++)
case '+':
/* Make sure we can specify the matching operand. */
if (i > 9)
error ("output operand constraint %d contains `+'", i);
/* Replace '+' with '='. */
found_plus = 1;
case '=':
found_equal = 1;
case '?': case '!': case '*': case '%': case '&':
case 'V': case 'm': case 'o': case '<': case '>':
case 'E': case 'F': case 'G': case 'H': case 'X':
case 's': case 'i': case 'n':
case 'I': case 'J': case 'K': case 'L': case 'M':
case 'N': case 'O': case 'P': case ',':
case 'Q': case 'R': case 'S': case 'T': case 'U':
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
error ("matching constraint not valid in output operand");
case 'p': case 'g': case 'r':
allows_reg = 1;
if (! found_equal && ! found_plus)
error ("output operand constraint lacks `='");
/* If an output operand is not a decl or indirect ref and our constraint
allows a register, make a temporary to act as an intermediate.
Make the asm insn write into that, then our caller will copy it to
the real output operand. Likewise for promoted variables. */
|| (TREE_CODE_CLASS (TREE_CODE (val)) == 'd'
&& ! (GET_CODE (DECL_RTL (val)) == REG
&& GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
|| ! allows_reg
|| found_plus)
if (! allows_reg)
mark_addressable (TREE_VALUE (tail));
= expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode,
if (! allows_reg && GET_CODE (output_rtx[i]) != MEM)
error ("output number %d not directly addressable", i);
output_rtx[i] = assign_temp (type, 0, 0, 0);
TREE_VALUE (tail) = make_tree (type, output_rtx[i]);
if (found_plus)
inout_mode[ninout] = TYPE_MODE (TREE_TYPE (TREE_VALUE (tail)));
inout_opnum[ninout++] = i;
ninputs += ninout;
if (ninputs + noutputs > MAX_RECOG_OPERANDS)
error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
/* Make vectors for the expression-rtx and constraint strings. */
argvec = rtvec_alloc (ninputs);
constraints = rtvec_alloc (ninputs);
body = gen_rtx_ASM_OPERANDS (VOIDmode,
TREE_STRING_POINTER (string), "", 0, argvec,
constraints, filename, line);
MEM_VOLATILE_P (body) = vol;
/* Eval the inputs and put them into ARGVEC.
Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
i = 0;
for (tail = inputs; tail; tail = TREE_CHAIN (tail))
int j;
int allows_reg = 0;
/* If there's an erroneous arg, emit no insn,
because the ASM_INPUT would get VOIDmode
and that could cause a crash in reload. */
if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
error ("hard register `%s' listed as input operand to `asm'",
/* Make sure constraint has neither `=' nor `+'. */
for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)) - 1; j++)
case '+': case '=':
error ("input operand constraint contains `%c'",
case '?': case '!': case '*': case '%': case '&':
case 'V': case 'm': case 'o': case '<': case '>':
case 'E': case 'F': case 'G': case 'H': case 'X':
case 's': case 'i': case 'n':
case 'I': case 'J': case 'K': case 'L': case 'M':
case 'N': case 'O': case 'P': case ',':
case 'Q': case 'R': case 'S': case 'T': case 'U':
/* Whether or not a numeric constraint allows a register is
decided by the matching constraint, and so there is no need
to do anything special with them. We must handle them in
the default case, so that we don't unnecessarily force
operands to memory. */
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
>= '0' + noutputs)
("matching constraint references invalid operand number");
/* ... fall through ... */
case 'p': case 'g': case 'r':
allows_reg = 1;
if (! allows_reg)
mark_addressable (TREE_VALUE (tail));
XVECEXP (body, 3, i) /* argvec */
= expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
if (CONSTANT_P (XVECEXP (body, 3, i))
&& ! general_operand (XVECEXP (body, 3, i),
if (allows_reg)
XVECEXP (body, 3, i)
= force_reg (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
XVECEXP (body, 3, i));
XVECEXP (body, 3, i)
= force_const_mem (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
XVECEXP (body, 3, i));
if (! allows_reg
&& (GET_CODE (XVECEXP (body, 3, i)) == REG
|| GET_CODE (XVECEXP (body, 3, i)) == SUBREG
|| GET_CODE (XVECEXP (body, 3, i)) == CONCAT))
tree type = TREE_TYPE (TREE_VALUE (tail));
rtx memloc = assign_temp (type, 1, 1, 1);
emit_move_insn (memloc, XVECEXP (body, 3, i));
XVECEXP (body, 3, i) = memloc;
XVECEXP (body, 4, i) /* constraints */
/* Protect all the operands from the queue,
now that they have all been evaluated. */
for (i = 0; i < ninputs - ninout; i++)
XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
for (i = 0; i < noutputs; i++)
output_rtx[i] = protect_from_queue (output_rtx[i], 1);
/* For in-out operands, copy output rtx to input rtx. */
for (i = 0; i < ninout; i++)
static char match[9+1][2]
= {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
int j = inout_opnum[i];
XVECEXP (body, 3, ninputs - ninout + i) /* argvec */
= output_rtx[j];
XVECEXP (body, 4, ninputs - ninout + i) /* constraints */
= gen_rtx_ASM_INPUT (inout_mode[j], match[j]);
/* Now, for each output, construct an rtx
If there is more than one, put them inside a PARALLEL. */
if (noutputs == 1 && nclobbers == 0)
insn = emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
else if (noutputs == 0 && nclobbers == 0)
/* No output operands: put in a raw ASM_OPERANDS rtx. */
insn = emit_insn (body);
rtx obody = body;
int num = noutputs;
if (num == 0) num = 1;
body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
/* For each output operand, store a SET. */
for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
XVECEXP (body, 0, i)
= gen_rtx_SET (VOIDmode,
gen_rtx_ASM_OPERANDS (VOIDmode,
i, argvec, constraints,
filename, line));
MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
/* If there are no outputs (but there are some clobbers)
store the bare ASM_OPERANDS into the PARALLEL. */
if (i == 0)
XVECEXP (body, 0, i++) = obody;
/* Store (clobber REG) for each clobbered register specified. */
for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
int j = decode_reg_name (regname);
if (j < 0)
if (j == -3) /* `cc', which is not a register */
if (j == -4) /* `memory', don't cache memory across asm */
XVECEXP (body, 0, i++)
= gen_rtx_CLOBBER (VOIDmode,
gen_rtx_MEM (BLKmode,
gen_rtx_SCRATCH (VOIDmode)));
/* Ignore unknown register, error already signaled. */
/* Use QImode since that's guaranteed to clobber just one reg. */
XVECEXP (body, 0, i++)
= gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (QImode, j));
insn = emit_insn (body);
free_temp_slots ();
/* Generate RTL to evaluate the expression EXP
and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
expand_expr_stmt (exp)
tree exp;
/* If -W, warn about statements with no side effects,
except for an explicit cast to void (e.g. for assert()), and
except inside a ({...}) where they may be useful. */
if (expr_stmts_for_value == 0 && exp != error_mark_node)
if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
&& TREE_TYPE (exp) == void_type_node))
warning_with_file_and_line (emit_filename, emit_lineno,
"statement with no effect");
else if (warn_unused)
warn_if_unused_value (exp);
/* If EXP is of function type and we are expanding statements for
value, convert it to pointer-to-function. */
if (expr_stmts_for_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
last_expr_type = TREE_TYPE (exp);
if (flag_syntax_only && ! expr_stmts_for_value)
last_expr_value = 0;
last_expr_value = expand_expr (exp,
? NULL_RTX : const0_rtx),
VOIDmode, 0);
/* If all we do is reference a volatile value in memory,
copy it to a register to be sure it is actually touched. */
if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
copy_to_reg (last_expr_value);
rtx lab = gen_label_rtx ();
/* Compare the value with itself to reference it. */
emit_cmp_insn (last_expr_value, last_expr_value, EQ,
expand_expr (TYPE_SIZE (last_expr_type),
NULL_RTX, VOIDmode, 0),
BLKmode, 0,
TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT);
emit_jump_insn ((*bcc_gen_fctn[(int) EQ]) (lab));
emit_label (lab);
/* If this expression is part of a ({...}) and is in memory, we may have
to preserve temporaries. */
preserve_temp_slots (last_expr_value);
/* Free any temporaries used to evaluate this expression. Any temporary
used as a result of this expression will already have been preserved
above. */
free_temp_slots ();
emit_queue ();
/* Warn if EXP contains any computations whose results are not used.
Return 1 if a warning is printed; 0 otherwise. */
warn_if_unused_value (exp)
tree exp;
if (TREE_USED (exp))
return 0;
switch (TREE_CODE (exp))
case RTL_EXPR:
/* We don't warn about COND_EXPR because it may be a useful
construct if either arm contains a side effect. */
return 0;
/* For a binding, warn if no side effect within it. */
return warn_if_unused_value (TREE_OPERAND (exp, 1));
return warn_if_unused_value (TREE_OPERAND (exp, 1));
/* In && or ||, warn if 2nd operand has no side effect. */
return warn_if_unused_value (TREE_OPERAND (exp, 1));
return 0;
if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
return 1;
/* Let people do `(foo (), 0)' without a warning. */
return 0;
return warn_if_unused_value (TREE_OPERAND (exp, 1));
case NOP_EXPR:
/* Don't warn about values cast to void. */
if (TREE_TYPE (exp) == void_type_node)
return 0;
/* Don't warn about conversions not explicit in the user's program. */
return 0;
/* Assignment to a cast usually results in a cast of a modify.
Don't complain about that. There can be an arbitrary number of
casts before the modify, so we must loop until we find the first
non-cast expression and then test to see if that is a modify. */
tree tem = TREE_OPERAND (exp, 0);
while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
tem = TREE_OPERAND (tem, 0);
|| TREE_CODE (tem) == CALL_EXPR)
return 0;
goto warn;
/* Don't warn about automatic dereferencing of references, since
the user cannot control it. */
return warn_if_unused_value (TREE_OPERAND (exp, 0));
/* ... fall through ... */
/* Referencing a volatile value is a side effect, so don't warn. */
if ((TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
|| TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
return 0;
warning_with_file_and_line (emit_filename, emit_lineno,
"value computed is not used");
return 1;
/* Clear out the memory of the last expression evaluated. */
clear_last_expr ()
last_expr_type = 0;
/* Begin a statement which will return a value.
Return the RTL_EXPR for this statement expr.
The caller must save that value and pass it to expand_end_stmt_expr. */
expand_start_stmt_expr ()
int momentary;
tree t;
/* Make the RTL_EXPR node temporary, not momentary,
so that rtl_expr_chain doesn't become garbage. */
momentary = suspend_momentary ();
t = make_node (RTL_EXPR);
resume_momentary (momentary);
do_pending_stack_adjust ();
start_sequence_for_rtl_expr (t);
return t;
/* Restore the previous state at the end of a statement that returns a value.
Returns a tree node representing the statement's value and the
insns to compute the value.
The nodes of that expression have been freed by now, so we cannot use them.
But we don't want to do that anyway; the expression has already been
evaluated and now we just want to use the value. So generate a RTL_EXPR
with the proper type and RTL value.
If the last substatement was not an expression,
return something with type `void'. */
expand_end_stmt_expr (t)
tree t;
if (last_expr_type == 0)
last_expr_type = void_type_node;
last_expr_value = const0_rtx;
else if (last_expr_value == 0)
/* There are some cases where this can happen, such as when the
statement is void type. */
last_expr_value = const0_rtx;
else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
/* Remove any possible QUEUED. */
last_expr_value = protect_from_queue (last_expr_value, 0);
emit_queue ();
TREE_TYPE (t) = last_expr_type;
RTL_EXPR_RTL (t) = last_expr_value;
RTL_EXPR_SEQUENCE (t) = get_insns ();
rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
end_sequence ();
/* Don't consider deleting this expr or containing exprs at tree level. */
/* Propagate volatility of the actual RTL expr. */
TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
last_expr_type = 0;
return t;
/* Generate RTL for the start of an if-then. COND is the expression
whose truth should be tested.
If EXITFLAG is nonzero, this conditional is visible to
`exit_something'. */
expand_start_cond (cond, exitflag)
tree cond;
int exitflag;
struct nesting *thiscond = ALLOC_NESTING ();
/* Make an entry on cond_stack for the cond we are entering. */
thiscond->next = cond_stack;
thiscond->all = nesting_stack;
thiscond->depth = ++nesting_depth;
thiscond->data.cond.next_label = gen_label_rtx ();
/* Before we encounter an `else', we don't need a separate exit label
unless there are supposed to be exit statements
to exit this conditional. */
thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
thiscond->data.cond.endif_label = thiscond->exit_label;
cond_stack = thiscond;
nesting_stack = thiscond;
do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
/* Generate RTL between then-clause and the elseif-clause
of an if-then-elseif-.... */
expand_start_elseif (cond)
tree cond;
if (cond_stack->data.cond.endif_label == 0)
cond_stack->data.cond.endif_label = gen_label_rtx ();
emit_jump (cond_stack->data.cond.endif_label);
emit_label (cond_stack->data.cond.next_label);
cond_stack->data.cond.next_label = gen_label_rtx ();
do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
/* Generate RTL between the then-clause and the else-clause
of an if-then-else. */
expand_start_else ()
if (cond_stack->data.cond.endif_label == 0)
cond_stack->data.cond.endif_label = gen_label_rtx ();
emit_jump (cond_stack->data.cond.endif_label);
emit_label (cond_stack->data.cond.next_label);
cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
/* After calling expand_start_else, turn this "else" into an "else if"
by providing another condition. */
expand_elseif (cond)
tree cond;
cond_stack->data.cond.next_label = gen_label_rtx ();
do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
/* Generate RTL for the end of an if-then.
Pop the record for it off of cond_stack. */
expand_end_cond ()
struct nesting *thiscond = cond_stack;
do_pending_stack_adjust ();
if (thiscond->data.cond.next_label)
emit_label (thiscond->data.cond.next_label);
if (thiscond->data.cond.endif_label)
emit_label (thiscond->data.cond.endif_label);
POPSTACK (cond_stack);
last_expr_type = 0;
/* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
loop should be exited by `exit_something'. This is a loop for which
`expand_continue' will jump to the top of the loop.
Make an entry on loop_stack to record the labels associated with
this loop. */
struct nesting *
expand_start_loop (exit_flag)
int exit_flag;
register struct nesting *thisloop = ALLOC_NESTING ();
/* Make an entry on loop_stack for the loop we are entering. */
thisloop->next = loop_stack;
thisloop->all = nesting_stack;
thisloop->depth = ++nesting_depth;
thisloop->data.loop.start_label = gen_label_rtx ();
thisloop->data.loop.end_label = gen_label_rtx ();
thisloop->data.loop.alt_end_label = 0;
thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
loop_stack = thisloop;
nesting_stack = thisloop;
do_pending_stack_adjust ();
emit_queue ();
emit_label (thisloop->data.loop.start_label);
return thisloop;
/* Like expand_start_loop but for a loop where the continuation point
(for expand_continue_loop) will be specified explicitly. */
struct nesting *
expand_start_loop_continue_elsewhere (exit_flag)
int exit_flag;
struct nesting *thisloop = expand_start_loop (exit_flag);
loop_stack->data.loop.continue_label = gen_label_rtx ();
return thisloop;
/* Specify the continuation point for a loop started with
Use this at the point in the code to which a continue statement
should jump. */
expand_loop_continue_here ()
do_pending_stack_adjust ();
emit_label (loop_stack->data.loop.continue_label);
/* Finish a loop. Generate a jump back to the top and the loop-exit label.
Pop the block off of loop_stack. */
expand_end_loop ()
register rtx insn;
register rtx start_label;
rtx last_test_insn = 0;
int num_insns = 0;
insn = get_last_insn ();
start_label = loop_stack->data.loop.start_label;
/* Mark the continue-point at the top of the loop if none elsewhere. */
if (start_label == loop_stack->data.loop.continue_label)
emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
do_pending_stack_adjust ();
/* If optimizing, perhaps reorder the loop. If the loop starts with
a loop exit, roll that to the end where it will optimize together
with the jump back.
We look for the conditional branch to the exit, except that once
we find such a branch, we don't look past 30 instructions.
In more detail, if the loop presently looks like this (in pseudo-C):
if (test) goto end_label;
goto start_label;
transform it to look like:
goto start_label;
if (test) goto end_label;
goto newstart_label;
Here, the `test' may actually consist of some reasonably complex
code, terminating in a test. */
if (optimize
! (GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) == SET
&& SET_DEST (PATTERN (insn)) == pc_rtx
int eh_regions = 0;
/* Scan insns from the top of the loop looking for a qualified
conditional exit. */
for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
insn = NEXT_INSN (insn))
if (GET_CODE (insn) == NOTE)
if (optimize < 2
/* The code that actually moves the exit test will
carefully leave BLOCK notes in their original
location. That means, however, that we can't debug
the exit test itself. So, we refuse to move code
containing BLOCK notes at low optimization levels. */
if (eh_regions < 0)
/* We've come to the end of an EH region, but
never saw the beginning of that region. That
means that an EH region begins before the top
of the loop, and ends in the middle of it. The
existence of such a situation violates a basic
assumption in this code, since that would imply
that even when EH_REGIONS is zero, we might
move code out of an exception region. */
abort ();
/* We already know this INSN is a NOTE, so there's no
point in looking at it to see if it's a JUMP. */
if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
if (last_test_insn && num_insns > 30)
if (eh_regions > 0)
/* We don't want to move a partial EH region. Consider:
while ( ( { try {
if (cond ()) 0;
else {
} catch (...) {
} )) {
This isn't legal C++, but here's what it's supposed to
mean: if cond() is true, stop looping. Otherwise,
call bar, and keep looping. In addition, if cond
throws an exception, catch it and keep looping. Such
constructs are certainy legal in LISP.
We should not move the `if (cond()) 0' test since then
the EH-region for the try-block would be broken up.
(In this case we would the EH_BEG note for the `try'
and `if cond()' but not the call to bar() or the
EH_END note.)
So we don't look for tests within an EH region. */
if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == SET
&& SET_DEST (PATTERN (insn)) == pc_rtx
&& ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
== loop_stack->data.loop.end_label)
|| (XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
== loop_stack->data.loop.alt_end_label)))
&& ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
== loop_stack->data.loop.end_label)
|| (XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
== loop_stack->data.loop.alt_end_label)))))
last_test_insn = insn;
if (last_test_insn == 0 && GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) == SET
&& SET_DEST (PATTERN (insn)) == pc_rtx
&& ((XEXP (SET_SRC (PATTERN (insn)), 0)
== loop_stack->data.loop.end_label)
|| (XEXP (SET_SRC (PATTERN (insn)), 0)
== loop_stack->data.loop.alt_end_label)))
/* Include BARRIER. */
last_test_insn = NEXT_INSN (insn);
if (last_test_insn != 0 && last_test_insn != get_last_insn ())
/* We found one. Move everything from there up
to the end of the loop, and add a jump into the loop
to jump to there. */
register rtx newstart_label = gen_label_rtx ();
register rtx start_move = start_label;
rtx next_insn;
/* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
then we want to move this note also. */
if (GET_CODE (PREV_INSN (start_move)) == NOTE
&& (NOTE_LINE_NUMBER (PREV_INSN (start_move))
start_move = PREV_INSN (start_move);
emit_label_after (newstart_label, PREV_INSN (start_move));
/* Actually move the insns. Start at the beginning, and
keep copying insns until we've copied the
last_test_insn. */
for (insn = start_move; insn; insn = next_insn)
/* Figure out which insn comes after this one. We have
to do this before we move INSN. */
if (insn == last_test_insn)
/* We've moved all the insns. */
next_insn = NULL_RTX;
next_insn = NEXT_INSN (insn);
if (GET_CODE (insn) == NOTE
/* We don't want to move NOTE_INSN_BLOCK_BEGs or
NOTE_INSN_BLOCK_ENDs because the correct generation
of debugging information depends on these appearing
in the same order in the RTL and in the tree
structure, where they are represented as BLOCKs.
So, we don't move block notes. Of course, moving
the code inside the block is likely to make it
impossible to debug the instructions in the exit
test, but such is the price of optimization. */
/* Move the INSN. */
reorder_insns (insn, insn, get_last_insn ());
emit_jump_insn_after (gen_jump (start_label),
PREV_INSN (newstart_label));
emit_barrier_after (PREV_INSN (newstart_label));
start_label = newstart_label;
emit_jump (start_label);
emit_label (loop_stack->data.loop.end_label);
POPSTACK (loop_stack);
last_expr_type = 0;
/* Generate a jump to the current loop's continue-point.
This is usually the top of the loop, but may be specified
explicitly elsewhere. If not currently inside a loop,
return 0 and do nothing; caller will print an error message. */
expand_continue_loop (whichloop)
struct nesting *whichloop;
last_expr_type = 0;
if (whichloop == 0)
whichloop = loop_stack;
if (whichloop == 0)
return 0;
expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
return 1;
/* Generate a jump to exit the current loop. If not currently inside a loop,
return 0 and do nothing; caller will print an error message. */
expand_exit_loop (whichloop)
struct nesting *whichloop;
last_expr_type = 0;
if (whichloop == 0)
whichloop = loop_stack;
if (whichloop == 0)
return 0;
expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
return 1;
/* Generate a conditional jump to exit the current loop if COND
evaluates to zero. If not currently inside a loop,
return 0 and do nothing; caller will print an error message. */
expand_exit_loop_if_false (whichloop, cond)
struct nesting *whichloop;
tree cond;
rtx label = gen_label_rtx ();
rtx last_insn;
last_expr_type = 0;
if (whichloop == 0)
whichloop = loop_stack;
if (whichloop == 0)
return 0;
/* In order to handle fixups, we actually create a conditional jump
around a unconditional branch to exit the loop. If fixups are
necessary, they go before the unconditional branch. */
do_jump (cond, NULL_RTX, label);
last_insn = get_last_insn ();
if (GET_CODE (last_insn) == CODE_LABEL)
whichloop->data.loop.alt_end_label = last_insn;
expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
emit_label (label);
return 1;
/* Return non-zero if we should preserve sub-expressions as separate
pseudos. We never do so if we aren't optimizing. We always do so
if -fexpensive-optimizations.
Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
the loop may still be a small one. */
preserve_subexpressions_p ()
rtx insn;
if (flag_expensive_optimizations)
return 1;
if (optimize == 0 || loop_stack == 0)
return 0;
insn = get_last_insn_anywhere ();
return (insn
&& (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
< n_non_fixed_regs * 3));
/* Generate a jump to exit the current loop, conditional, binding contour
or case statement. Not all such constructs are visible to this function,
only those started with EXIT_FLAG nonzero. Individual languages use
the EXIT_FLAG parameter to control which kinds of constructs you can
exit this way.
If not currently inside anything that can be exited,
return 0 and do nothing; caller will print an error message. */
expand_exit_something ()
struct nesting *n;
last_expr_type = 0;
for (n = nesting_stack; n; n = n->all)
if (n->exit_label != 0)
expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
return 1;
return 0;
/* Generate RTL to return from the current function, with no value.
(That is, we do not do anything about returning any value.) */
expand_null_return ()
struct nesting *block = block_stack;
rtx last_insn = 0;
/* Does any pending block have cleanups? */
while (block && block->data.block.cleanups == 0)
block = block->next;
/* If yes, use a goto to return, since that runs cleanups. */
expand_null_return_1 (last_insn, block != 0);
/* Generate RTL to return from the current function, with value VAL. */
static void
expand_value_return (val)
rtx val;
struct nesting *block = block_stack;
rtx last_insn = get_last_insn ();
rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
/* Copy the value to the return location
unless it's already there. */
if (return_reg != val)
tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
int unsignedp = TREE_UNSIGNED (type);
enum machine_mode mode
= promote_mode (type, DECL_MODE (DECL_RESULT (current_function_decl)),
&unsignedp, 1);
if (GET_MODE (val) != VOIDmode && GET_MODE (val) != mode)
convert_move (return_reg, val, unsignedp);
emit_move_insn (return_reg, val);
if (GET_CODE (return_reg) == REG
emit_insn (gen_rtx_USE (VOIDmode, return_reg));
/* Handle calls that return values in multiple non-contiguous locations.
The Irix 6 ABI has examples of this. */
else if (GET_CODE (return_reg) == PARALLEL)
int i;
for (i = 0; i < XVECLEN (return_reg, 0); i++)
rtx x = XEXP (XVECEXP (return_reg, 0, i), 0);
if (GET_CODE (x) == REG
emit_insn (gen_rtx_USE (VOIDmode, x));
/* Does any pending block have cleanups? */
while (block && block->data.block.cleanups == 0)
block = block->next;
/* If yes, use a goto to return, since that runs cleanups.
Use LAST_INSN to put cleanups *before* the move insn emitted above. */
expand_null_return_1 (last_insn, block != 0);
/* Output a return with no value. If LAST_INSN is nonzero,
pretend that the return takes place after LAST_INSN.
If USE_GOTO is nonzero then don't use a return instruction;
go to the return label instead. This causes any cleanups
of pending blocks to be executed normally. */
static void
expand_null_return_1 (last_insn, use_goto)
rtx last_insn;
int use_goto;
rtx end_label = cleanup_label ? cleanup_label : return_label;
clear_pending_stack_adjust ();
do_pending_stack_adjust ();
last_expr_type = 0;
/* PCC-struct return always uses an epilogue. */
if (current_function_returns_pcc_struct || use_goto)
if (end_label == 0)
end_label = return_label = gen_label_rtx ();
expand_goto_internal (NULL_TREE, end_label, last_insn);
/* Otherwise output a simple return-insn if one is available,
unless it won't do the job. */
#ifdef HAVE_return
if (HAVE_return && use_goto == 0 && cleanup_label == 0)
emit_jump_insn (gen_return ());
emit_barrier ();
/* Otherwise jump to the epilogue. */
expand_goto_internal (NULL_TREE, end_label, last_insn);
/* Generate RTL to evaluate the expression RETVAL and return it
from the current function. */
expand_return (retval)
tree retval;
/* If there are any cleanups to be performed, then they will
be inserted following LAST_INSN. It is desirable
that the last_insn, for such purposes, should be the
last insn before computing the return value. Otherwise, cleanups
which call functions can clobber the return value. */
/* ??? rms: I think that is erroneous, because in C++ it would
run destructors on variables that might be used in the subsequent
computation of the return value. */
rtx last_insn = 0;
register rtx val = 0;
register rtx op0;
tree retval_rhs;
int cleanups;
/* If function wants no value, give it none. */
if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
expand_expr (retval, NULL_RTX, VOIDmode, 0);
emit_queue ();
expand_null_return ();
/* Are any cleanups needed? E.g. C++ destructors to be run? */
/* This is not sufficient. We also need to watch for cleanups of the
expression we are about to expand. Unfortunately, we cannot know
if it has cleanups until we expand it, and we want to change how we
expand it depending upon if we need cleanups. We can't win. */
#if 0
cleanups = any_pending_cleanups (1);
cleanups = 1;
if (TREE_CODE (retval) == RESULT_DECL)
retval_rhs = retval;
else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
retval_rhs = TREE_OPERAND (retval, 1);
else if (TREE_TYPE (retval) == void_type_node)
/* Recognize tail-recursive call to void function. */
retval_rhs = retval;
retval_rhs = NULL_TREE;
/* Only use `last_insn' if there are cleanups which must be run. */
if (cleanups || cleanup_label != 0)
last_insn = get_last_insn ();
/* Distribute return down conditional expr if either of the sides
may involve tail recursion (see test below). This enhances the number
of tail recursions we see. Don't do this always since it can produce
sub-optimal code in some cases and we distribute assignments into
conditional expressions when it would help. */
if (optimize && retval_rhs != 0
&& frame_offset == 0
&& TREE_CODE (retval_rhs) == COND_EXPR
&& (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
|| TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
rtx label = gen_label_rtx ();
tree expr;
do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
DECL_RESULT (current_function_decl),
TREE_OPERAND (retval_rhs, 1));
expand_return (expr);
emit_label (label);
expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
DECL_RESULT (current_function_decl),
TREE_OPERAND (retval_rhs, 2));
expand_return (expr);
/* For tail-recursive call to current function,
just jump back to the beginning.
It's unsafe if any auto variable in this function
has its address taken; for simplicity,
require stack frame to be empty. */
if (optimize && retval_rhs != 0
&& frame_offset == 0
&& TREE_CODE (retval_rhs) == CALL_EXPR
&& TREE_CODE (TREE_OPERAND (retval_rhs, 0)) == ADDR_EXPR
&& TREE_OPERAND (TREE_OPERAND (retval_rhs, 0), 0) == current_function_decl
/* Finish checking validity, and if valid emit code
to set the argument variables for the new call. */
&& tail_recursion_args (TREE_OPERAND (retval_rhs, 1),
DECL_ARGUMENTS (current_function_decl)))
if (tail_recursion_label == 0)
tail_recursion_label = gen_label_rtx ();
emit_label_after (tail_recursion_label,
emit_queue ();
expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
emit_barrier ();
#ifdef HAVE_return
/* This optimization is safe if there are local cleanups
because expand_null_return takes care of them.
??? I think it should also be safe when there is a cleanup label,
because expand_null_return takes care of them, too.
Any reason why not? */
if (HAVE_return && cleanup_label == 0
&& ! current_function_returns_pcc_struct
&& BRANCH_COST <= 1)
/* If this is return x == y; then generate
if (x == y) return 1; else return 0;
if we can do it with explicit return insns and branches are cheap,
but not if we have the corresponding scc insn. */
int has_scc = 0;
if (retval_rhs)
switch (TREE_CODE (retval_rhs))
case EQ_EXPR:
#ifdef HAVE_seq
has_scc = HAVE_seq;
case NE_EXPR:
#ifdef HAVE_sne
has_scc = HAVE_sne;
case GT_EXPR:
#ifdef HAVE_sgt
has_scc = HAVE_sgt;
case GE_EXPR:
#ifdef HAVE_sge
has_scc = HAVE_sge;
case LT_EXPR:
#ifdef HAVE_slt
has_scc = HAVE_slt;
case LE_EXPR:
#ifdef HAVE_sle
has_scc = HAVE_sle;
if (! has_scc)
op0 = gen_label_rtx ();
jumpifnot (retval_rhs, op0);
expand_value_return (const1_rtx);
emit_label (op0);
expand_value_return (const0_rtx);
#endif /* HAVE_return */
/* If the result is an aggregate that is being returned in one (or more)
registers, load the registers here. The compiler currently can't handle
copying a BLKmode value into registers. We could put this code in a
more general area (for use by everyone instead of just function
call/return), but until this feature is generally usable it is kept here
(and in expand_call). The value must go into a pseudo in case there
are cleanups that will clobber the real return register. */
if (retval_rhs != 0
&& TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
&& GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
int i, bitpos, xbitpos;
int big_endian_correction = 0;
int bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)),BITS_PER_WORD);
rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
enum machine_mode tmpmode, result_reg_mode;
/* Structures whose size is not a multiple of a word are aligned
to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
machine, this means we must skip the empty high order bytes when
calculating the bit offset. */
big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
/* Copy the structure BITSIZE bits at a time. */
for (bitpos = 0, xbitpos = big_endian_correction;
bitpos < bytes * BITS_PER_UNIT;
bitpos += bitsize, xbitpos += bitsize)
/* We need a new destination pseudo each time xbitpos is
on a word boundary and when xbitpos == big_endian_correction
(the first time through). */
if (xbitpos % BITS_PER_WORD == 0
|| xbitpos == big_endian_correction)
/* Generate an appropriate register. */
dst = gen_reg_rtx (word_mode);
result_pseudos[xbitpos / BITS_PER_WORD] = dst;
/* Clobber the destination before we move anything into it. */
emit_insn (gen_rtx_CLOBBER (VOIDmode, dst));
/* We need a new source operand each time bitpos is on a word
boundary. */
if (bitpos % BITS_PER_WORD == 0)
src = operand_subword_force (result_val,
bitpos / BITS_PER_WORD,
/* Use bitpos for the source extraction (left justified) and
xbitpos for the destination store (right justified). */
store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
extract_bit_field (src, bitsize,
bitpos % BITS_PER_WORD, 1,
NULL_RTX, word_mode,
bitsize / BITS_PER_UNIT,
/* Find the smallest integer mode large enough to hold the
entire structure and use that mode instead of BLKmode
on the USE insn for the return register. */
bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
tmpmode != MAX_MACHINE_MODE;
tmpmode = GET_MODE_WIDER_MODE (tmpmode))
/* Have we found a large enough mode? */
if (GET_MODE_SIZE (tmpmode) >= bytes)
/* No suitable mode found. */
if (tmpmode == MAX_MACHINE_MODE)
abort ();
PUT_MODE (DECL_RTL (DECL_RESULT (current_function_decl)), tmpmode);
if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
result_reg_mode = word_mode;
result_reg_mode = tmpmode;
result_reg = gen_reg_rtx (result_reg_mode);
emit_queue ();
for (i = 0; i < n_regs; i++)
emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
if (tmpmode != result_reg_mode)
result_reg = gen_lowpart (tmpmode, result_reg);
expand_value_return (result_reg);
else if (cleanups
&& retval_rhs != 0
&& TREE_TYPE (retval_rhs) != void_type_node
&& GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
/* Calculate the return value into a pseudo reg. */
val = gen_reg_rtx (DECL_MODE (DECL_RESULT (current_function_decl)));
val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
val = force_not_mem (val);
emit_queue ();
/* Return the calculated value, doing cleanups first. */
expand_value_return (val);
/* No cleanups or no hard reg used;
calculate value into hard return reg. */
expand_expr (retval, const0_rtx, VOIDmode, 0);
emit_queue ();
expand_value_return (DECL_RTL (DECL_RESULT (current_function_decl)));
/* Return 1 if the end of the generated RTX is not a barrier.
This means code already compiled can drop through. */
drop_through_at_end_p ()
rtx insn = get_last_insn ();
while (insn && GET_CODE (insn) == NOTE)
insn = PREV_INSN (insn);
return insn && GET_CODE (insn) != BARRIER;
/* Emit code to alter this function's formal parms for a tail-recursive call.
ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
FORMALS is the chain of decls of formals.
Return 1 if this can be done;
otherwise return 0 and do not emit any code. */
static int
tail_recursion_args (actuals, formals)
tree actuals, formals;
register tree a = actuals, f = formals;
register int i;
register rtx *argvec;
/* Check that number and types of actuals are compatible
with the formals. This is not always true in valid C code.
Also check that no formal needs to be addressable
and that all formals are scalars. */
/* Also count the args. */
for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
return 0;
if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
return 0;
if (a != 0 || f != 0)
return 0;
/* Compute all the actuals. */
argvec = (rtx *) alloca (i * sizeof (rtx));
for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
/* Find which actual values refer to current values of previous formals.
Copy each of them now, before any formal is changed. */
for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
int copy = 0;
register int j;
for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
{ copy = 1; break; }
if (copy)
argvec[i] = copy_to_reg (argvec[i]);
/* Store the values of the actuals into the formals. */
for (f = formals, a = actuals, i = 0; f;
f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
emit_move_insn (DECL_RTL (f), argvec[i]);
convert_move (DECL_RTL (f), argvec[i],
free_temp_slots ();
return 1;
/* Generate the RTL code for entering a binding contour.
The variables are declared one by one, by calls to `expand_decl'.
EXIT_FLAG is nonzero if this construct should be visible to
`exit_something'. */
expand_start_bindings (exit_flag)
int exit_flag;
struct nesting *thisblock = ALLOC_NESTING ();
rtx note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
/* Make an entry on block_stack for the block we are entering. */
thisblock->next = block_stack;
thisblock->all = nesting_stack;
thisblock->depth = ++nesting_depth;
thisblock->data.block.stack_level = 0;
thisblock->data.block.cleanups = 0;
thisblock->data.block.function_call_count = 0;
thisblock->data.block.exception_region = 0;
thisblock->data.block.target_temp_slot_level = target_temp_slot_level;
thisblock->data.block.conditional_code = 0;
thisblock->data.block.last_unconditional_cleanup = note;
thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
if (block_stack
&& !(block_stack->data.block.cleanups == NULL_TREE
&& block_stack->data.block.outer_cleanups == NULL_TREE))
= tree_cons (NULL_TREE, block_stack->data.block.cleanups,
thisblock->data.block.outer_cleanups = 0;
thisblock->data.block.label_chain = 0;
thisblock->data.block.innermost_stack_block = stack_block_stack;
thisblock->data.block.first_insn = note;
thisblock->data.block.block_start_count = ++block_start_count;
thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
block_stack = thisblock;
nesting_stack = thisblock;
/* Make a new level for allocating stack slots. */
push_temp_slots ();
/* Specify the scope of temporaries created by TARGET_EXPRs. Similar
to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
expand_expr are made. After we end the region, we know that all
space for all temporaries that were created by TARGET_EXPRs will be
destroyed and their space freed for reuse. */
expand_start_target_temps ()
/* This is so that even if the result is preserved, the space
allocated will be freed, as we know that it is no longer in use. */
push_temp_slots ();
/* Start a new binding layer that will keep track of all cleanup
actions to be performed. */
expand_start_bindings (0);
target_temp_slot_level = temp_slot_level;
expand_end_target_temps ()
expand_end_bindings (NULL_TREE, 0, 0);
/* This is so that even if the result is preserved, the space
allocated will be freed, as we know that it is no longer in use. */
pop_temp_slots ();
/* Mark top block of block_stack as an implicit binding for an
exception region. This is used to prevent infinite recursion when
ending a binding with expand_end_bindings. It is only ever called
by expand_eh_region_start, as that it the only way to create a
block stack for a exception region. */
mark_block_as_eh_region ()
block_stack->data.block.exception_region = 1;
if (block_stack->next
&& block_stack->next->data.block.conditional_code)
= block_stack->next->data.block.conditional_code;
= block_stack->next->data.block.last_unconditional_cleanup;
= block_stack->next->data.block.cleanup_ptr;
/* True if we are currently emitting insns in an area of output code
that is controlled by a conditional expression. This is used by
the cleanup handling code to generate conditional cleanup actions. */
conditional_context ()
return block_stack && block_stack->data.block.conditional_code;
/* Mark top block of block_stack as not for an implicit binding for an
exception region. This is only ever done by expand_eh_region_end
to let expand_end_bindings know that it is being called explicitly
to end the binding layer for just the binding layer associated with
the exception region, otherwise expand_end_bindings would try and
end all implicit binding layers for exceptions regions, and then
one normal binding layer. */
mark_block_as_not_eh_region ()
block_stack->data.block.exception_region = 0;
/* True if the top block of block_stack was marked as for an exception
region by mark_block_as_eh_region. */
is_eh_region ()
return block_stack && block_stack->data.block.exception_region;
/* Given a pointer to a BLOCK node, save a pointer to the most recently
generated NOTE_INSN_BLOCK_END in the BLOCK_END_NOTE field of the given
BLOCK node. */
remember_end_note (block)
register tree block;
BLOCK_END_NOTE (block) = last_block_end_note;
last_block_end_note = NULL_RTX;
/* Generate RTL code to terminate a binding contour.
VARS is the chain of VAR_DECL nodes
for the variables bound in this contour.
MARK_ENDS is nonzero if we should put a note at the beginning
and end of this binding contour.
DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
(That is true automatically if the contour has a saved stack level.) */
expand_end_bindings (vars, mark_ends, dont_jump_in)
tree vars;
int mark_ends;
int dont_jump_in;
register struct nesting *thisblock;
register tree decl;
while (block_stack->data.block.exception_region)
/* Because we don't need or want a new temporary level and
because we didn't create one in expand_eh_region_start,
create a fake one now to avoid removing one in
expand_end_bindings. */
push_temp_slots ();
block_stack->data.block.exception_region = 0;
expand_end_bindings (NULL_TREE, 0, 0);
/* Since expand_eh_region_start does an expand_start_bindings, we
have to first end all the bindings that were created by
expand_eh_region_start. */
thisblock = block_stack;
if (warn_unused)
for (decl = vars; decl; decl = TREE_CHAIN (decl))
if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL
&& DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
warning_with_decl (decl, "unused variable `%s'");
if (thisblock->exit_label)
do_pending_stack_adjust ();
emit_label (thisblock->exit_label);
/* If necessary, make a handler for nonlocal gotos taking
place in the function calls in this block. */
if (function_call_count != thisblock->data.block.function_call_count
&& nonlocal_labels
/* Make handler for outermost block
if there were any nonlocal gotos to this function. */
&& (thisblock->next == 0 ? current_function_has_nonlocal_label
/* Make handler for inner block if it has something
special to do when you jump out of it. */
: (thisblock->data.block.cleanups != 0
|| thisblock->data.block.stack_level != 0)))
tree link;
rtx afterward = gen_label_rtx ();
rtx handler_label = gen_label_rtx ();
rtx save_receiver = gen_reg_rtx (Pmode);
rtx insns;
/* Don't let jump_optimize delete the handler. */
LABEL_PRESERVE_P (handler_label) = 1;
/* Record the handler address in the stack slot for that purpose,
during this block, saving and restoring the outer value. */
if (thisblock->next != 0)
emit_move_insn (nonlocal_goto_handler_slot, save_receiver);
start_sequence ();
emit_move_insn (save_receiver, nonlocal_goto_handler_slot);
insns = get_insns ();
end_sequence ();
emit_insns_before (insns, thisblock->data.block.first_insn);
start_sequence ();
emit_move_insn (nonlocal_goto_handler_slot,
gen_rtx_LABEL_REF (Pmode, handler_label));
insns = get_insns ();
end_sequence ();
emit_insns_before (insns, thisblock->data.block.first_insn);
/* Jump around the handler; it runs only when specially invoked. */
emit_jump (afterward);
emit_label (handler_label);
#ifdef HAVE_nonlocal_goto
if (! HAVE_nonlocal_goto)
/* First adjust our frame pointer to its actual value. It was
previously set to the start of the virtual area corresponding to
the stacked variables when we branched here and now needs to be
adjusted to the actual hardware fp value.
Assignments are to virtual registers are converted by
instantiate_virtual_regs into the corresponding assignment
to the underlying register (fp in this case) that makes
the original assignment true.
So the following insn will actually be
decrementing fp by STARTING_FRAME_OFFSET. */
emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
if (fixed_regs[ARG_POINTER_REGNUM])
/* If the argument pointer can be eliminated in favor of the
frame pointer, we don't need to restore it. We assume here
that if such an elimination is present, it can always be used.
This is the case on all known machines; if we don't make this
assumption, we do unnecessary saving on many machines. */
static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
size_t i;
for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
if (elim_regs[i].from == ARG_POINTER_REGNUM
&& elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
if (i == sizeof elim_regs / sizeof elim_regs [0])
/* Now restore our arg pointer from the address at which it
was saved in our stack frame.
If there hasn't be space allocated for it yet, make
some now. */
if (arg_pointer_save_area == 0)
= assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
emit_move_insn (virtual_incoming_args_rtx,
/* We need a pseudo here, or else
instantiate_virtual_regs_1 complains. */
copy_to_reg (arg_pointer_save_area));
#ifdef HAVE_nonlocal_goto_receiver
if (HAVE_nonlocal_goto_receiver)
emit_insn (gen_nonlocal_goto_receiver ());
/* The handler expects the desired label address in the static chain
register. It tests the address and does an appropriate jump
to whatever label is desired. */
for (link = nonlocal_labels; link; link = TREE_CHAIN (link))
/* Skip any labels we shouldn't be able to jump to from here. */
if (! DECL_TOO_LATE (TREE_VALUE (link)))
rtx not_this = gen_label_rtx ();
rtx this = gen_label_rtx ();
do_jump_if_equal (static_chain_rtx,
gen_rtx_LABEL_REF (Pmode, DECL_RTL (TREE_VALUE (link))),
this, 0);
emit_jump (not_this);
emit_label (this);
expand_goto (TREE_VALUE (link));
emit_label (not_this);
/* If label is not recognized, abort. */
emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "abort"), 0,
VOIDmode, 0);
emit_barrier ();
emit_label (afterward);
/* Don't allow jumping into a block that has a stack level.
Cleanups are allowed, though. */
if (dont_jump_in
|| thisblock->data.block.stack_level != 0)
struct label_chain *chain;
/* Any labels in this block are no longer valid to go to.
Mark them to cause an error message. */
for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
DECL_TOO_LATE (chain->label) = 1;
/* If any goto without a fixup came to this label,
that must be an error, because gotos without fixups
come from outside all saved stack-levels. */
if (TREE_ADDRESSABLE (chain->label))
error_with_decl (chain->label,
"label `%s' used before containing binding contour");
/* Restore stack level in effect before the block
(only if variable-size objects allocated). */
/* Perform any cleanups associated with the block. */
if (thisblock->data.block.stack_level != 0
|| thisblock->data.block.cleanups != 0)
/* Only clean up here if this point can actually be reached. */
int reachable = GET_CODE (get_last_insn ()) != BARRIER;
/* Don't let cleanups affect ({...}) constructs. */
int old_expr_stmts_for_value = expr_stmts_for_value;
rtx old_last_expr_value = last_expr_value;
tree old_last_expr_type = last_expr_type;
expr_stmts_for_value = 0;
/* Do the cleanups. */
expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
if (reachable)
do_pending_stack_adjust ();
expr_stmts_for_value = old_expr_stmts_for_value;
last_expr_value = old_last_expr_value;
last_expr_type = old_last_expr_type;
/* Restore the stack level. */
if (reachable && thisblock->data.block.stack_level != 0)
emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
thisblock->data.block.stack_level, NULL_RTX);
if (nonlocal_goto_handler_slot != 0)
emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
/* Any gotos out of this block must also do these things.
Also report any gotos with fixups that came to labels in this
level. */
fixup_gotos (thisblock,
/* Mark the beginning and end of the scope if requested.
We do this now, after running cleanups on the variables
just going out of scope, so they are in scope for their cleanups. */
if (mark_ends)
last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
/* Get rid of the beginning-mark if we don't make an end-mark. */
NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
/* If doing stupid register allocation, make sure lives of all
register variables declared here extend thru end of scope. */
if (obey_regdecls)
for (decl = vars; decl; decl = TREE_CHAIN (decl))
rtx rtl = DECL_RTL (decl);
if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
use_variable (rtl);
/* Restore the temporary level of TARGET_EXPRs. */
target_temp_slot_level = thisblock->data.block.target_temp_slot_level;
/* Restore block_stack level for containing block. */
stack_block_stack = thisblock->data.block.innermost_stack_block;
POPSTACK (block_stack);
/* Pop the stack slot nesting and free any slots at this level. */
pop_temp_slots ();
/* Generate RTL for the automatic variable declaration DECL.
(Other kinds of declarations are simply ignored if seen here.) */
expand_decl (decl)
register tree decl;
struct nesting *thisblock = block_stack;
tree type;
type = TREE_TYPE (decl);
/* Only automatic variables need any expansion done.
Static and external variables, and external functions,
will be handled by `assemble_variable' (called from finish_decl).
TYPE_DECL and CONST_DECL require nothing.
PARM_DECLs are handled in `assign_parms'. */
if (TREE_CODE (decl) != VAR_DECL)
if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
/* Create the RTL representation for the variable. */
if (type == error_mark_node)
DECL_RTL (decl) = gen_rtx_MEM (BLKmode, const0_rtx);
else if (DECL_SIZE (decl) == 0)
/* Variable with incomplete type. */
if (DECL_INITIAL (decl) == 0)
/* Error message was already done; now avoid a crash. */
DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
/* An initializer is going to decide the size of this array.
Until we know the size, represent its address with a reg. */
DECL_RTL (decl) = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
else if (DECL_MODE (decl) != BLKmode
/* If -ffloat-store, don't put explicit float vars
into regs. */
&& !(flag_float_store
&& TREE_CODE (type) == REAL_TYPE)
&& (DECL_REGISTER (decl) || ! obey_regdecls)
/* if -fcheck-memory-usage, check all variables. */
&& ! flag_check_memory_usage)
/* Automatic variable that can go in a register. */
int unsignedp = TREE_UNSIGNED (type);
enum machine_mode reg_mode
= promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
DECL_RTL (decl) = gen_reg_rtx (reg_mode);
mark_user_reg (DECL_RTL (decl));
if (POINTER_TYPE_P (type))
mark_reg_pointer (DECL_RTL (decl),
else if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST
&& ! (flag_stack_check && ! STACK_CHECK_BUILTIN
&& (TREE_INT_CST_HIGH (DECL_SIZE (decl)) != 0
/* Variable of fixed size that goes on the stack. */
rtx oldaddr = 0;
rtx addr;
/* If we previously made RTL for this decl, it must be an array
whose size was determined by the initializer.
The old address was a register; set that register now
to the proper address. */
if (DECL_RTL (decl) != 0)
if (GET_CODE (DECL_RTL (decl)) != MEM
|| GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
abort ();
oldaddr = XEXP (DECL_RTL (decl), 0);