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/* Expands front end tree to back end RTL for GNU C-Compiler
Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
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 2, 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 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 "tm_p.h"
#include "flags.h"
#include "except.h"
#include "function.h"
#include "insn-config.h"
#include "expr.h"
#include "libfuncs.h"
#include "hard-reg-set.h"
#include "loop.h"
#include "recog.h"
#include "machmode.h"
#include "toplev.h"
#include "output.h"
#include "ggc.h"
#include "langhooks.h"
#include "predict.h"
/* Assume that case vectors are not pc-relative. */
#ifndef CASE_VECTOR_PC_RELATIVE
#define CASE_VECTOR_PC_RELATIVE 0
#endif
/* 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 GTY(())
{
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_[129];
static int use_cost_table;
static int cost_table_initialized;
/* Special care is needed because we allow -1, but TREE_INT_CST_LOW
is unsigned. */
#define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
/* 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 GTY(())
{
struct nesting *all;
struct nesting *next;
int depth;
rtx exit_label;
enum nesting_desc {
COND_NESTING,
LOOP_NESTING,
BLOCK_NESTING,
CASE_NESTING
} desc;
union nesting_u
{
/* For conds (if-then and if-then-else statements). */
struct nesting_cond
{
/* 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;
} GTY ((tag ("COND_NESTING"))) cond;
/* For loops. */
struct nesting_loop
{
/* 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;
} GTY ((tag ("LOOP_NESTING"))) loop;
/* For variable binding contours. */
struct nesting_block
{
/* 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 n_function_calls;
/* Nonzero if this is associated with an 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 block_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;
} GTY ((tag ("BLOCK_NESTING"))) block;
/* For switch (C) or case (Pascal) statements,
and also for dummies (see `expand_start_case_dummy'). */
struct nesting_case
{
/* 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;
/* Name of this kind of statement, for warnings. */
const 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;
} GTY ((tag ("CASE_NESTING"))) case_stmt;
} GTY ((desc ("%1.desc"))) data;
};
/* Allocate and return a new `struct nesting'. */
#define ALLOC_NESTING() \
(struct nesting *) ggc_alloc (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. */
#define POPSTACK(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; } \
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 GTY(())
{
/* 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;
};
/* Within any binding contour that must restore a stack level,
all labels are recorded with a chain of these structures. */
struct label_chain GTY(())
{
/* Points to following fixup. */
struct label_chain *next;
tree label;
};
struct stmt_status GTY(())
{
/* Chain of all pending binding contours. */
struct nesting * x_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 * x_stack_block_stack;
/* Chain of all pending conditional statements. */
struct nesting * x_cond_stack;
/* Chain of all pending loops. */
struct nesting * x_loop_stack;
/* Chain of all pending case or switch statements. */
struct nesting * x_case_stack;
/* Separate chain including all of the above,
chained through the `all' field. */
struct nesting * x_nesting_stack;
/* Number of entries on nesting_stack now. */
int x_nesting_depth;
/* Number of binding contours started so far in this function. */
int x_block_start_count;
/* Each time we expand an expression-statement,
record the expr's type and its RTL value here. */
tree x_last_expr_type;
rtx x_last_expr_value;
/* 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 x_expr_stmts_for_value;
/* Filename and line number of last line-number note,
whether we actually emitted it or not. */
const char *x_emit_filename;
int x_emit_lineno;
struct goto_fixup *x_goto_fixup_chain;
};
#define block_stack (cfun->stmt->x_block_stack)
#define stack_block_stack (cfun->stmt->x_stack_block_stack)
#define cond_stack (cfun->stmt->x_cond_stack)
#define loop_stack (cfun->stmt->x_loop_stack)
#define case_stack (cfun->stmt->x_case_stack)
#define nesting_stack (cfun->stmt->x_nesting_stack)
#define nesting_depth (cfun->stmt->x_nesting_depth)
#define current_block_start_count (cfun->stmt->x_block_start_count)
#define last_expr_type (cfun->stmt->x_last_expr_type)
#define last_expr_value (cfun->stmt->x_last_expr_value)
#define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
#define emit_filename (cfun->stmt->x_emit_filename)
#define emit_lineno (cfun->stmt->x_emit_lineno)
#define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
/* Non-zero if we are using EH to handle cleanups. */
static int using_eh_for_cleanups_p = 0;
static int n_occurrences PARAMS ((int, const char *));
static bool parse_input_constraint PARAMS ((const char **, int, int, int,
int, const char * const *,
bool *, bool *));
static bool decl_conflicts_with_clobbers_p PARAMS ((tree, const HARD_REG_SET));
static void expand_goto_internal PARAMS ((tree, rtx, rtx));
static int expand_fixup PARAMS ((tree, rtx, rtx));
static rtx expand_nl_handler_label PARAMS ((rtx, rtx));
static void expand_nl_goto_receiver PARAMS ((void));
static void expand_nl_goto_receivers PARAMS ((struct nesting *));
static void fixup_gotos PARAMS ((struct nesting *, rtx, tree,
rtx, int));
static bool check_operand_nalternatives PARAMS ((tree, tree));
static bool check_unique_operand_names PARAMS ((tree, tree));
static tree resolve_operand_names PARAMS ((tree, tree, tree,
const char **));
static char *resolve_operand_name_1 PARAMS ((char *, tree, tree));
static void expand_null_return_1 PARAMS ((rtx));
static enum br_predictor return_prediction PARAMS ((rtx));
static void expand_value_return PARAMS ((rtx));
static int tail_recursion_args PARAMS ((tree, tree));
static void expand_cleanups PARAMS ((tree, tree, int, int));
static void check_seenlabel PARAMS ((void));
static void do_jump_if_equal PARAMS ((rtx, rtx, rtx, int));
static int estimate_case_costs PARAMS ((case_node_ptr));
static void group_case_nodes PARAMS ((case_node_ptr));
static void balance_case_nodes PARAMS ((case_node_ptr *,
case_node_ptr));
static int node_has_low_bound PARAMS ((case_node_ptr, tree));
static int node_has_high_bound PARAMS ((case_node_ptr, tree));
static int node_is_bounded PARAMS ((case_node_ptr, tree));
static void emit_jump_if_reachable PARAMS ((rtx));
static void emit_case_nodes PARAMS ((rtx, case_node_ptr, rtx, tree));
static struct case_node *case_tree2list PARAMS ((case_node *, case_node *));
void
using_eh_for_cleanups ()
{
using_eh_for_cleanups_p = 1;
}
void
init_stmt_for_function ()
{
cfun->stmt = ((struct stmt_status *)ggc_alloc (sizeof (struct stmt_status)));
/* 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;
current_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;
clear_last_expr ();
}
/* Return nonzero if anything is pushed on the loop, condition, or case
stack. */
int
in_control_zone_p ()
{
return cond_stack || loop_stack || case_stack;
}
/* Record the current file and line. Called from emit_line_note. */
void
set_file_and_line_for_stmt (file, line)
const char *file;
int line;
{
/* If we're outputting an inline function, and we add a line note,
there may be no CFUN->STMT information. So, there's no need to
update it. */
if (cfun->stmt)
{
emit_filename = file;
emit_lineno = line;
}
}
/* Emit a no-op instruction. */
void
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. */
rtx
label_rtx (label)
tree label;
{
if (TREE_CODE (label) != LABEL_DECL)
abort ();
if (!DECL_RTL_SET_P (label))
SET_DECL_RTL (label, gen_label_rtx ());
return DECL_RTL (label);
}
/* Add an unconditional jump to LABEL as the next sequential instruction. */
void
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. */
void
expand_computed_goto (exp)
tree exp;
{
rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
#ifdef POINTERS_EXTEND_UNSIGNED
if (GET_MODE (x) != Pmode)
x = convert_memory_address (Pmode, x);
#endif
emit_queue ();
if (! cfun->computed_goto_common_label)
{
cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
cfun->computed_goto_common_label = gen_label_rtx ();
do_pending_stack_adjust ();
emit_label (cfun->computed_goto_common_label);
emit_indirect_jump (cfun->computed_goto_common_reg);
current_function_has_computed_jump = 1;
}
else
{
emit_move_insn (cfun->computed_goto_common_reg, x);
emit_jump (cfun->computed_goto_common_label);
}
}
/* 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. */
void
expand_label (label)
tree label;
{
struct label_chain *p;
do_pending_stack_adjust ();
emit_label (label_rtx (label));
if (DECL_NAME (label))
LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
if (stack_block_stack != 0)
{
p = (struct label_chain *) ggc_alloc (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. */
void
declare_nonlocal_label (label)
tree label;
{
rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
LABEL_PRESERVE_P (label_rtx (label)) = 1;
if (nonlocal_goto_handler_slots == 0)
{
emit_stack_save (SAVE_NONLOCAL,
&nonlocal_goto_stack_level,
PREV_INSN (tail_recursion_reentry));
}
nonlocal_goto_handler_slots
= gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
}
/* 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'. */
void
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 handler_slot, static_chain, save_area, insn;
tree link;
/* Find the corresponding handler slot for this label. */
handler_slot = p->x_nonlocal_goto_handler_slots;
for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
link = TREE_CHAIN (link))
handler_slot = XEXP (handler_slot, 1);
handler_slot = XEXP (handler_slot, 0);
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. */
static_chain = copy_to_reg (lookup_static_chain (label));
/* Get addr of containing function's current nonlocal goto handler,
which will do any cleanups and then jump to the label. */
handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
virtual_stack_vars_rtx,
static_chain));
/* Get addr of containing function's nonlocal save area. */
save_area = p->x_nonlocal_goto_stack_level;
if (save_area)
save_area = replace_rtx (copy_rtx (save_area),
virtual_stack_vars_rtx, static_chain);
#if HAVE_nonlocal_goto
if (HAVE_nonlocal_goto)
emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
save_area, label_ref));
else
#endif
{
/* 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, static_chain);
emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
/* 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_indirect_jump (handler_slot);
}
/* Search backwards to the jump insn and mark it as a
non-local goto. */
for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
{
if (GET_CODE (insn) == JUMP_INSN)
{
REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
const0_rtx, REG_NOTES (insn));
break;
}
else if (GET_CODE (insn) == CALL_INSN)
break;
}
}
else
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))
break;
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 ();
/* Don't do this adjust if it's to the end label and this function
is to return with a depressed stack pointer. */
if (label == return_label
&& (((TREE_CODE (TREE_TYPE (current_function_decl))
== FUNCTION_TYPE)
&& (TYPE_RETURNS_STACK_DEPRESSED
(TREE_TYPE (current_function_decl))))))
;
else
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",
IDENTIFIER_POINTER (DECL_NAME (body)));
}
/* 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)
TREE_ADDRESSABLE (body) = 1;
}
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;
else
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)
break;
if (block != end_block)
{
/* Ok, a fixup is needed. Add a fixup to the list of such. */
struct goto_fixup *fixup
= (struct goto_fixup *) ggc_alloc (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
NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
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.
Note that optimization passes (including expand_end_loop)
might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
as a placeholder. */
{
rtx original_before_jump
= last_insn ? last_insn : get_last_insn ();
rtx start;
rtx end;
tree block;
block = make_node (BLOCK);
TREE_USED (block) = 1;
if (!cfun->x_whole_function_mode_p)
(*lang_hooks.decls.insert_block) (block);
else
{
BLOCK_CHAIN (block)
= BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
= block;
}
start_sequence ();
start = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
if (cfun->x_whole_function_mode_p)
NOTE_BLOCK (start) = block;
fixup->before_jump = emit_note (NULL, NOTE_INSN_DELETED);
end = emit_note (NULL, NOTE_INSN_BLOCK_END);
if (cfun->x_whole_function_mode_p)
NOTE_BLOCK (end) = block;
fixup->context = block;
end_sequence ();
emit_insn_after (start, original_before_jump);
}
fixup->block_start_count = current_block_start_count;
fixup->stack_level = 0;
fixup->cleanup_list_list
= ((block->data.block.outer_cleanups
|| block->data.block.cleanups)
? tree_cons (NULL_TREE, block->data.block.cleanups,
block->data.block.outer_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. */
void
expand_fixups (first_insn)
rtx first_insn;
{
fixup_gotos (NULL, 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;
{
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)
{
rtx cleanup_insns;
/* If this fixup jumped into this contour from before the beginning
of this contour, report an error. This code used to use
the first non-label insn after f->target_rtl, but that's
wrong since such can be added, by things like put_var_into_stack
and have INSN_UIDs that are out of the range of the block. */
/* ??? 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)
&& INSN_UID (first_insn) < INSN_UID (f->target_rtl)
&& 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. */
(*lang_hooks.decls.pushlevel) (0);
(*lang_hooks.decls.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. */
if (TREE_ADDRESSABLE (lists)
&& 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
&& ! (f->target_rtl == return_label
&& ((TREE_CODE (TREE_TYPE (current_function_decl))
== FUNCTION_TYPE)
&& (TYPE_RETURNS_STACK_DEPRESSED
(TREE_TYPE (current_function_decl))))))
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 ();
(*lang_hooks.decls.poplevel) (1, 0, 0);
end_sequence ();
emit_insn_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 ();
(*lang_hooks.decls.pushlevel) (0);
(*lang_hooks.decls.set_block) (f->context);
expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
do_pending_stack_adjust ();
cleanup_insns = get_insns ();
(*lang_hooks.decls.poplevel) (1, 0, 0);
end_sequence ();
if (cleanup_insns != 0)
f->before_jump
= emit_insn_after (cleanup_insns, f->before_jump);
f->cleanup_list_list = TREE_CHAIN (lists);
}
if (stack_level)
f->stack_level = stack_level;
}
}
/* Return the number of times character C occurs in string S. */
static int
n_occurrences (c, s)
int c;
const char *s;
{
int n = 0;
while (*s)
n += (*s++ == c);
return n;
}
/* Generate RTL for an asm statement (explicit assembler code).
STRING is a STRING_CST node containing the assembler code text,
or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
insn is volatile; don't optimize it. */
void
expand_asm (string, vol)
tree string;
int vol;
{
rtx body;
if (TREE_CODE (string) == ADDR_EXPR)
string = TREE_OPERAND (string, 0);
body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
MEM_VOLATILE_P (body) = vol;
emit_insn (body);
clear_last_expr ();
}
/* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
inputs and NOUTPUTS outputs to this extended-asm. Upon return,
*ALLOWS_MEM will be TRUE iff the constraint allows the use of a
memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
constraint allows the use of a register operand. And, *IS_INOUT
will be true if the operand is read-write, i.e., if it is used as
an input as well as an output. If *CONSTRAINT_P is not in
canonical form, it will be made canonical. (Note that `+' will be
rpelaced with `=' as part of this process.)
Returns TRUE if all went well; FALSE if an error occurred. */
bool
parse_output_constraint (constraint_p, operand_num, ninputs, noutputs,
allows_mem, allows_reg, is_inout)
const char **constraint_p;
int operand_num;
int ninputs;
int noutputs;
bool *allows_mem;
bool *allows_reg;
bool *is_inout;
{
const char *constraint = *constraint_p;
const char *p;
/* Assume the constraint doesn't allow the use of either a register
or memory. */
*allows_mem = false;
*allows_reg = false;
/* Allow the `=' or `+' to not be at the beginning of the string,
since it wasn't explicitly documented that way, and there is a
large body of code that puts it last. Swap the character to
the front, so as not to uglify any place else. */
p = strchr (constraint, '=');
if (!p)
p = strchr (constraint, '+');
/* If the string doesn't contain an `=', issue an error
message. */
if (!p)
{
error ("output operand constraint lacks `='");
return false;
}
/* If the constraint begins with `+', then the operand is both read
from and written to. */
*is_inout = (*p == '+');
/* Canonicalize the output constraint so that it begins with `='. */
if (p != constraint || is_inout)
{
char *buf;
size_t c_len = strlen (constraint);
if (p != constraint)
warning ("output constraint `%c' for operand %d is not at the beginning",
*p, operand_num);
/* Make a copy of the constraint. */
buf = alloca (c_len + 1);
strcpy (buf, constraint);
/* Swap the first character and the `=' or `+'. */
buf[p - constraint] = buf[0];
/* Make sure the first character is an `='. (Until we do this,
it might be a `+'.) */
buf[0] = '=';
/* Replace the constraint with the canonicalized string. */
*constraint_p = ggc_alloc_string (buf, c_len);
constraint = *constraint_p;
}
/* Loop through the constraint string. */
for (p = constraint + 1; *p; ++p)
switch (*p)
{
case '+':
case '=':
error ("operand constraint contains incorrectly positioned '+' or '='");
return false;
case '%':
if (operand_num + 1 == ninputs + noutputs)
{
error ("`%%' constraint used with last operand");
return false;
}
break;
case 'V': case 'm': case 'o':
*allows_mem = true;
break;
case '?': case '!': case '*': case '&': case '#':
case 'E': case 'F': case 'G': case 'H':
case 's': case 'i': case 'n':
case 'I': case 'J': case 'K': case 'L': case 'M':
case 'N': case 'O': case 'P': case ',':
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
case '[':
error ("matching constraint not valid in output operand");
return false;
case '<': case '>':
/* ??? Before flow, auto inc/dec insns are not supposed to exist,
excepting those that expand_call created. So match memory
and hope. */
*allows_mem = true;
break;
case 'g': case 'X':
*allows_reg = true;
*allows_mem = true;
break;
case 'p': case 'r':
*allows_reg = true;
break;
default:
if (!ISALPHA (*p))
break;
if (REG_CLASS_FROM_LETTER (*p) != NO_REGS)
*allows_reg = true;
#ifdef EXTRA_CONSTRAINT
else if (EXTRA_ADDRESS_CONSTRAINT (*p))
*allows_reg = true;
else if (EXTRA_MEMORY_CONSTRAINT (*p))
*allows_mem = true;
else
{
/* Otherwise we can't assume anything about the nature of
the constraint except that it isn't purely registers.
Treat it like "g" and hope for the best. */
*allows_reg = true;
*allows_mem = true;
}
#endif
break;
}
return true;
}
/* Similar, but for input constraints. */
static bool
parse_input_constraint (constraint_p, input_num, ninputs, noutputs, ninout,
constraints, allows_mem, allows_reg)
const char **constraint_p;
int input_num;
int ninputs;
int noutputs;
int ninout;
const char * const * constraints;
bool *allows_mem;
bool *allows_reg;
{
const char *constraint = *constraint_p;
const char *orig_constraint = constraint;
size_t c_len = strlen (constraint);
size_t j;
/* Assume the constraint doesn't allow the use of either
a register or memory. */
*allows_mem = false;
*allows_reg = false;
/* Make sure constraint has neither `=', `+', nor '&'. */
for (j = 0; j < c_len; j++)
switch (constraint[j])
{
case '+': case '=': case '&':
if (constraint == orig_constraint)
{
error ("input operand constraint contains `%c'", constraint[j]);
return false;
}
break;
case '%':
if (constraint == orig_constraint
&& input_num + 1 == ninputs - ninout)
{
error ("`%%' constraint used with last operand");
return false;
}
break;
case 'V': case 'm': case 'o':
*allows_mem = true;
break;
case '<': case '>':
case '?': case '!': case '*': case '#':
case 'E': case 'F': case 'G': case 'H':
case 's': case 'i': case 'n':
case 'I': case 'J': case 'K': case 'L': case 'M':
case 'N': case 'O': case 'P': case ',':
break;
/* 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':
{
char *end;
unsigned long match;
match = strtoul (constraint + j, &end, 10);
if (match >= (unsigned long) noutputs)
{
error ("matching constraint references invalid operand number");
return false;
}
/* Try and find the real constraint for this dup. Only do this
if the matching constraint is the only alternative. */
if (*end == '\0'
&& (j == 0 || (j == 1 && constraint[0] == '%')))
{
constraint = constraints[match];
*constraint_p = constraint;
c_len = strlen (constraint);
j = 0;
break;
}
else
j = end - constraint;
}
/* Fall through. */
case 'p': case 'r':
*allows_reg = true;
break;
case 'g': case 'X':
*allows_reg = true;
*allows_mem = true;
break;
default:
if (! ISALPHA (constraint[j]))
{
error ("invalid punctuation `%c' in constraint", constraint[j]);
return false;
}
if (REG_CLASS_FROM_LETTER (constraint[j]) != NO_REGS)
*allows_reg = true;
#ifdef EXTRA_CONSTRAINT
else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j]))
*allows_reg = true;
else if (EXTRA_MEMORY_CONSTRAINT (constraint[j]))
*allows_mem = true;
else
{
/* Otherwise we can't assume anything about the nature of
the constraint except that it isn't purely registers.
Treat it like "g" and hope for the best. */
*allows_reg = true;
*allows_mem = true;
}
#endif
break;
}
return true;
}
/* Check for overlap between registers marked in CLOBBERED_REGS and
anything inappropriate in DECL. Emit error and return TRUE for error,
FALSE for ok. */
static bool
decl_conflicts_with_clobbers_p (decl, clobbered_regs)
tree decl;
const HARD_REG_SET clobbered_regs;
{
/* Conflicts between asm-declared register variables and the clobber
list are not allowed. */
if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
&& DECL_REGISTER (decl)
&& REG_P (DECL_RTL (decl))
&& REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
{
rtx reg = DECL_RTL (decl);
unsigned int regno;
for (regno = REGNO (reg);
regno < (REGNO (reg)
+ HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
regno++)
if (TEST_HARD_REG_BIT (clobbered_regs, regno))
{
error ("asm-specifier for variable `%s' conflicts with asm clobber list",
IDENTIFIER_POINTER (DECL_NAME (decl)));
/* Reset registerness to stop multiple errors emitted for a
single variable. */
DECL_REGISTER (decl) = 0;
return true;
}
}
return false;
}
/* 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
and a tree list in TREE_PURPOSE which in turn contains a constraint
name in TREE_VALUE (or NULL_TREE) and a constraint string
in 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. */
void
expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
tree string, outputs, inputs, clobbers;
int vol;
const char *filename;
int line;
{
rtvec argvec, constraintvec;
rtx body;
int ninputs = list_length (inputs);
int noutputs = list_length (outputs);
int ninout;
int nclobbers;
HARD_REG_SET clobbered_regs;
int clobber_conflict_found = 0;
tree tail;
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));
rtx *real_output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
enum machine_mode *inout_mode
= (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
const char **constraints
= (const char **) alloca ((noutputs + ninputs) * sizeof (const char *));
/* The insn we have emitted. */
rtx insn;
int old_generating_concat_p = generating_concat_p;
/* An ASM with no outputs needs to be treated as volatile, for now. */
if (noutputs == 0)
vol = 1;
if (! check_operand_nalternatives (outputs, inputs))
return;
if (! check_unique_operand_names (outputs, inputs))
return;
string = resolve_operand_names (string, outputs, inputs, constraints);
#ifdef MD_ASM_CLOBBERS
/* Sometimes we wish to automatically clobber registers across an asm.
Case in point is when the i386 backend moved from cc0 to a hard reg --
maintaining source-level compatibility means automatically clobbering
the flags register. */
MD_ASM_CLOBBERS (clobbers);
#endif
/* Count the number of meaningful clobbered registers, ignoring what
we would ignore later. */
nclobbers = 0;
CLEAR_HARD_REG_SET (clobbered_regs);
for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
{
const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
i = decode_reg_name (regname);
if (i >= 0 || i == -4)
++nclobbers;
else if (i == -2)
error ("unknown register name `%s' in `asm'", regname);
/* Mark clobbered registers. */
if (i >= 0)
SET_HARD_REG_BIT (clobbered_regs, i);
}
clear_last_expr ();
/* First pass over inputs and outputs checks validity and sets
mark_addressable if needed. */
ninout = 0;
for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
{
tree val = TREE_VALUE (tail);
tree type = TREE_TYPE (val);
const char *constraint;
bool is_inout;
bool allows_reg;
bool allows_mem;
/* If there's an erroneous arg, emit no insn. */
if (type == error_mark_node)
return;
/* Try to parse the output constraint. If that fails, there's
no point in going further. */
constraint = constraints[i];
if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
&allows_mem, &allows_reg, &is_inout))
return;
if (! allows_reg
&& (allows_mem
|| is_inout
|| (DECL_P (val)
&& GET_CODE (DECL_RTL (val)) == REG
&& GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
(*lang_hooks.mark_addressable) (val);
if (is_inout)
ninout++;
}
ninputs += ninout;
if (ninputs + noutputs > MAX_RECOG_OPERANDS)
{
error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
return;
}
for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
{
bool allows_reg, allows_mem;
const char *constraint;
/* 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)
return;
constraint = constraints[i + noutputs];
if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
constraints, &allows_mem, &allows_reg))
return;
if (! allows_reg && allows_mem)
(*lang_hooks.mark_addressable) (TREE_VALUE (tail));
}
/* Second pass evaluates arguments. */
ninout = 0;
for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
{
tree val = TREE_VALUE (tail);
tree type = TREE_TYPE (val);
bool is_inout;
bool allows_reg;
bool allows_mem;
rtx op;
if (!parse_output_constraint (&constraints[i], i, ninputs,
noutputs, &allows_mem, &allows_reg,
&is_inout))
abort ();
/* 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. */
generating_concat_p = 0;
real_output_rtx[i] = NULL_RTX;
if ((TREE_CODE (val) == INDIRECT_REF
&& allows_mem)
|| (DECL_P (val)
&& (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
&& ! (GET_CODE (DECL_RTL (val)) == REG
&& GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
|| ! allows_reg
|| is_inout)
{
op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
if (GET_CODE (op) == MEM)
op = validize_mem (op);
if (! allows_reg && GET_CODE (op) != MEM)
error ("output number %d not directly addressable", i);
if ((! allows_mem && GET_CODE (op) == MEM)
|| GET_CODE (op) == CONCAT)
{
real_output_rtx[i] = protect_from_queue (op, 1);
op = gen_reg_rtx (GET_MODE (op));
if (is_inout)
emit_move_insn (op, real_output_rtx[i]);
}
}
else
{
op = assign_temp (type, 0, 0, 1);
op = validize_mem (op);
TREE_VALUE (tail) = make_tree (type, op);
}
output_rtx[i] = op;
generating_concat_p = old_generating_concat_p;
if (is_inout)
{
inout_mode[ninout] = TYPE_MODE (type);
inout_opnum[ninout++] = i;
}
if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
clobber_conflict_found = 1;
}
/* Make vectors for the expression-rtx, constraint strings,
and named operands. */
argvec = rtvec_alloc (ninputs);
constraintvec = rtvec_alloc (ninputs);
body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
: GET_MODE (output_rtx[0])),
TREE_STRING_POINTER (string),
empty_string, 0, argvec, constraintvec,
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. */
for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
{
bool allows_reg, allows_mem;
const char *constraint;
tree val, type;
rtx op;
constraint = constraints[i + noutputs];
if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
constraints, &allows_mem, &allows_reg))
abort ();
generating_concat_p = 0;
val = TREE_VALUE (tail);
type = TREE_TYPE (val);
op = expand_expr (val, NULL_RTX, VOIDmode,
(allows_mem && !allows_reg
? EXPAND_MEMORY : EXPAND_NORMAL));
/* Never pass a CONCAT to an ASM. */
if (GET_CODE (op) == CONCAT)
op = force_reg (GET_MODE (op), op);
else if (GET_CODE (op) == MEM)
op = validize_mem (op);
if (asm_operand_ok (op, constraint) <= 0)
{
if (allows_reg)
op = force_reg (TYPE_MODE (type), op);
else if (!allows_mem)
warning ("asm operand %d probably doesn't match constraints",
i + noutputs);
else if (GET_CODE (op) == MEM)
{
/* We won't recognize either volatile memory or memory
with a queued address as available a memory_operand
at this point. Ignore it: clearly this *is* a memory. */
}
else
{
warning ("use of memory input without lvalue in asm operand %d is deprecated",
i + noutputs);
if (CONSTANT_P (op))
{
op = force_const_mem (TYPE_MODE (type), op);
op = validize_mem (op);
}
else if (GET_CODE (op) == REG
|| GET_CODE (op) == SUBREG
|| GET_CODE (op) == ADDRESSOF
|| GET_CODE (op) == CONCAT)
{
tree qual_type = build_qualified_type (type,
(TYPE_QUALS (type)
| TYPE_QUAL_CONST));
rtx memloc = assign_temp (qual_type, 1, 1, 1);
memloc = validize_mem (memloc);
emit_move_insn (memloc, op);
op = memloc;
}
}
}
generating_concat_p = old_generating_concat_p;
ASM_OPERANDS_INPUT (body, i) = op;
ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
= gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
clobber_conflict_found = 1;
}
/* Protect all the operands from the queue now that they have all been
evaluated. */
generating_concat_p = 0;
for (i = 0; i < ninputs - ninout; i++)
ASM_OPERANDS_INPUT (body, i)
= protect_from_queue (ASM_OPERANDS_INPUT (body, 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++)
{
int j = inout_opnum[i];
char buffer[16];
ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
= output_rtx[j];
sprintf (buffer, "%d", j);
ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
= gen_rtx_ASM_INPUT (inout_mode[i], ggc_alloc_string (buffer, -1));
}
generating_concat_p = old_generating_concat_p;
/* Now, for each output, construct an rtx
(set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
ARGVEC CONSTRAINTS OPNAMES))
If there is more than one, put them inside a PARALLEL. */
if (noutputs == 1 && nclobbers == 0)
{
ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[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);
}
else
{
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,
output_rtx[i],
gen_rtx_ASM_OPERANDS
(GET_MODE (output_rtx[i]),
TREE_STRING_POINTER (string),
constraints[i], i, argvec, constraintvec,
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))
{
const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
int j = decode_reg_name (regname);
rtx clobbered_reg;
if (j < 0)
{
if (j == -3) /* `cc', which is not a register */
continue;
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)));
continue;
}
/* Ignore unknown register, error already signaled. */
continue;
}
/* Use QImode since that's guaranteed to clobber just one reg. */
clobbered_reg = gen_rtx_REG (QImode, j);
/* Do sanity check for overlap between clobbers and respectively
input and outputs that hasn't been handled. Such overlap
should have been detected and reported above. */
if (!clobber_conflict_found)
{
int opno;
/* We test the old body (obody) contents to avoid tripping
over the under-construction body. */
for (opno = 0; opno < noutputs; opno++)
if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
internal_error ("asm clobber conflict with output operand");
for (opno = 0; opno < ninputs - ninout; opno++)
if (reg_overlap_mentioned_p (clobbered_reg,
ASM_OPERANDS_INPUT (obody, opno)))
internal_error ("asm clobber conflict with input operand");
}
XVECEXP (body, 0, i++)
= gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
}
insn = emit_insn (body);
}
/* For any outputs that needed reloading into registers, spill them
back to where they belong. */
for (i = 0; i < noutputs; ++i)
if (real_output_rtx[i])
emit_move_insn (real_output_rtx[i], output_rtx[i]);
free_temp_slots ();
}
/* A subroutine of expand_asm_operands. Check that all operands have
the same number of alternatives. Return true if so. */
static bool
check_operand_nalternatives (outputs, inputs)
tree outputs, inputs;
{
if (outputs || inputs)
{
tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
int nalternatives
= n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
tree next = inputs;
if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
{
error ("too many alternatives in `asm'");
return false;
}
tmp = outputs;
while (tmp)
{
const char *constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
if (n_occurrences (',', constraint) != nalternatives)
{
error ("operand constraints for `asm' differ in number of alternatives");
return false;
}
if (TREE_CHAIN (tmp))
tmp = TREE_CHAIN (tmp);
else
tmp = next, next = 0;
}
}
return true;
}
/* A subroutine of expand_asm_operands. Check that all operand names
are unique. Return true if so. We rely on the fact that these names
are identifiers, and so have been canonicalized by get_identifier,
so all we need are pointer comparisons. */
static bool
check_unique_operand_names (outputs, inputs)
tree outputs, inputs;
{
tree i, j;
for (i = outputs; i ; i = TREE_CHAIN (i))
{
tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
if (! i_name)
continue;
for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
goto failure;
}
for (i = inputs; i ; i = TREE_CHAIN (i))
{
tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
if (! i_name)
continue;
for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
goto failure;
for (j = outputs; j ; j = TREE_CHAIN (j))
if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
goto failure;
}
return true;
failure:
error ("duplicate asm operand name '%s'",
TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
return false;
}
/* A subroutine of expand_asm_operands. Resolve the names of the operands
in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
STRING and in the constraints to those numbers. */
static tree
resolve_operand_names (string, outputs, inputs, pconstraints)
tree string;
tree outputs, inputs;
const char **pconstraints;
{
char *buffer = xstrdup (TREE_STRING_POINTER (string));
char *p;
tree t;
/* Assume that we will not need extra space to perform the substitution.
This because we get to remove '[' and ']', which means we cannot have
a problem until we have more than 999 operands. */
p = buffer;
while ((p = strchr (p, '%')) != NULL)
{
if (p[1] == '[')
p += 1;
else if (ISALPHA (p[1]) && p[2] == '[')
p += 2;
else
{
p += 1;
continue;
}
p = resolve_operand_name_1 (p, outputs, inputs);
}
string = build_string (strlen (buffer), buffer);
free (buffer);
/* Collect output constraints here because it's convenient.
There should be no named operands here; this is verified
in expand_asm_operand. */
for (t = outputs; t ; t = TREE_CHAIN (t), pconstraints++)
*pconstraints = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
/* Substitute [<name>] in input constraint strings. */
for (t = inputs; t ; t = TREE_CHAIN (t), pconstraints++)
{
const char *c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
if (strchr (c, '[') == NULL)
*pconstraints = c;
else
{
p = buffer = xstrdup (c);
while ((p = strchr (p, '[')) != NULL)
p = resolve_operand_name_1 (p, outputs, inputs);
*pconstraints = ggc_alloc_string (buffer, -1);
free (buffer);
}
}
return string;
}
/* A subroutine of resolve_operand_names. P points to the '[' for a
potential named operand of the form [<name>]. In place, replace
the name and brackets with a number. Return a pointer to the
balance of the string after substitution. */
static char *
resolve_operand_name_1 (p, outputs, inputs)
char *p;
tree outputs, inputs;
{
char *q;
int op;
tree t;
size_t len;
/* Collect the operand name. */
q = strchr (p, ']');
if (!q)
{
error ("missing close brace for named operand");
return strchr (p, '\0');
}
len = q - p - 1;
/* Resolve the name to a number. */
for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
{
tree name = TREE_PURPOSE (TREE_PURPOSE (t));
if (name)
{
const char *c = TREE_STRING_POINTER (name);
if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
goto found;
}
}
for (t = inputs; t ; t = TREE_CHAIN (t), op++)
{
tree name = TREE_PURPOSE (TREE_PURPOSE (t));
if (name)
{
const char *c = TREE_STRING_POINTER (name);
if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
goto found;
}
}
*q = '\0';
error ("undefined named operand '%s'", p + 1);
op = 0;
found:
/* Replace the name with the number. Unfortunately, not all libraries
get the return value of sprintf correct, so search for the end of the
generated string by hand. */
sprintf (p, "%d", op);
p = strchr (p, '\0');
/* Verify the no extra buffer space assumption. */
if (p > q)
abort ();
/* Shift the rest of the buffer down to fill the gap. */
memmove (p, q + 1, strlen (q + 1) + 1);
return p;
}
/* Generate RTL to evaluate the expression EXP
and remember it in case this is the VALUE in a ({... VALUE; }) constr.
Provided just for backward-compatibility. expand_expr_stmt_value()
should be used for new code. */
void
expand_expr_stmt (exp)
tree exp;
{
expand_expr_stmt_value (exp, -1, 1);
}
/* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
whether to (1) save the value of the expression, (0) discard it or
(-1) use expr_stmts_for_value to tell. The use of -1 is
deprecated, and retained only for backward compatibility. */
void
expand_expr_stmt_value (exp, want_value, maybe_last)
tree exp;
int want_value, maybe_last;
{
rtx value;
tree type;
if (want_value == -1)
want_value = expr_stmts_for_value != 0;
/* If -W, warn about statements with no side effects,
except for an explicit cast to void (e.g. for assert()), and
except for last statement in ({...}) where they may be useful. */
if (! want_value
&& (expr_stmts_for_value == 0 || ! maybe_last)
&& exp != error_mark_node)
{
if (! TREE_SIDE_EFFECTS (exp))
{
if ((extra_warnings || warn_unused_value)
&& !(TREE_CODE (exp) == CONVERT_EXPR
&& VOID_TYPE_P (TREE_TYPE (exp))))
warning_with_file_and_line (emit_filename, emit_lineno,
"statement with no effect");
}
else if (warn_unused_value)
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 (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
/* The call to `expand_expr' could cause last_expr_type and
last_expr_value to get reset. Therefore, we set last_expr_value
and last_expr_type *after* calling expand_expr. */
value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
VOIDmode, 0);
type = TREE_TYPE (exp);
/* If all we do is reference a volatile value in memory,
copy it to a register to be sure it is actually touched. */
if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
{
if (TYPE_MODE (type) == VOIDmode)
;
else if (TYPE_MODE (type) != BLKmode)
value = copy_to_reg (value);
else
{
rtx lab = gen_label_rtx ();
/* Compare the value with itself to reference it. */
emit_cmp_and_jump_insns (value, value, EQ,
expand_expr (TYPE_SIZE (type),
NULL_RTX, VOIDmode, 0),
BLKmode, 0, lab);
emit_label (lab);
}
}
/* If this expression is part of a ({...}) and is in memory, we may have
to preserve temporaries. */
preserve_temp_slots (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 ();
if (want_value)
{
last_expr_value = value;
last_expr_type = type;
}
emit_queue ();
}
/* Warn if EXP contains any computations whose results are not used.
Return 1 if a warning is printed; 0 otherwise. */
int
warn_if_unused_value (exp)
tree exp;
{
if (TREE_USED (exp))
return 0;
/* Don't warn about void constructs. This includes casting to void,
void function calls, and statement expressions with a final cast
to void. */
if (VOID_TYPE_P (TREE_TYPE (exp)))
return 0;
switch (TREE_CODE (exp))
{
case PREINCREMENT_EXPR:
case POSTINCREMENT_EXPR:
case PREDECREMENT_EXPR:
case POSTDECREMENT_EXPR:
case MODIFY_EXPR:
case INIT_EXPR:
case TARGET_EXPR:
case CALL_EXPR:
case METHOD_CALL_EXPR:
case RTL_EXPR:
case TRY_CATCH_EXPR:
case WITH_CLEANUP_EXPR:
case EXIT_EXPR:
return 0;
case BIND_EXPR:
/* For a binding, warn if no side effect within it. */
return warn_if_unused_value (TREE_OPERAND (exp, 1));
case SAVE_EXPR:
return warn_if_unused_value (TREE_OPERAND (exp, 1));
case TRUTH_ORIF_EXPR:
case TRUTH_ANDIF_EXPR:
/* In && or ||, warn if 2nd operand has no side effect. */
return warn_if_unused_value (TREE_OPERAND (exp, 1));
case COMPOUND_EXPR:
if (TREE_NO_UNUSED_WARNING (exp))
return 0;
if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
return 1;
/* Let people do `(foo (), 0)' without a warning. */
if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
return 0;
return warn_if_unused_value (TREE_OPERAND (exp, 1));
case NOP_EXPR:
case CONVERT_EXPR:
case NON_LVALUE_EXPR:
/* Don't warn about conversions not explicit in the user's program. */
if (TREE_NO_UNUSED_WARNING (exp))
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);
if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
|| TREE_CODE (tem) == CALL_EXPR)
return 0;
}
goto maybe_warn;
case INDIRECT_REF:
/* Don't warn about automatic dereferencing of references, since
the user cannot control it. */
if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
return warn_if_unused_value (TREE_OPERAND (exp, 0));
/* Fall through. */
default:
/* Referencing a volatile value is a side effect, so don't warn. */
if ((DECL_P (exp)
|| TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
&& TREE_THIS_VOLATILE (exp))
return 0;
/* If this is an expression which has no operands, there is no value
to be unused. There are no such language-independent codes,
but front ends may define such. */
if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
&& TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
return 0;
maybe_warn:
/* If this is an expression with side effects, don't warn. */
if (TREE_SIDE_EFFECTS (exp))
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. */
void
clear_last_expr ()
{
last_expr_type = NULL_TREE;
last_expr_value = NULL_RTX;
}
/* Begin a statement-expression, i.e., a series of statements which
may 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. If HAS_SCOPE is nonzero, temporaries created
in the statement-expression are deallocated at the end of the
expression. */
tree
expand_start_stmt_expr (has_scope)
int has_scope;
{
tree t;
/* Make the RTL_EXPR node temporary, not momentary,
so that rtl_expr_chain doesn't become garbage. */
t = make_node (RTL_EXPR);
do_pending_stack_adjust ();
if (has_scope)
start_sequence_for_rtl_expr (t);
else
start_sequence ();
NO_DEFER_POP;
expr_stmts_for_value++;
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'. */
tree
expand_end_stmt_expr (t)
tree t;
{
OK_DEFER_POP;
if (! last_expr_value || ! last_expr_type)
{
last_expr_value = const0_rtx;
last_expr_type = void_type_node;
}
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. */
TREE_SIDE_EFFECTS (t) = 1;
/* Propagate volatility of the actual RTL expr. */
TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
clear_last_expr ();
expr_stmts_for_value--;
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'. */
void
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->desc = COND_NESTING;
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-.... */
void
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. */
void
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. */
void
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. */
void
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);
clear_last_expr ();
}
/* 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;
{
struct nesting *thisloop = ALLOC_NESTING ();
/* Make an entry on loop_stack for the loop we are entering. */
thisloop->desc = LOOP_NESTING;
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_note (NULL, NOTE_INSN_LOOP_BEG);
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;
}
/* Begin a null, aka do { } while (0) "loop". But since the contents
of said loop can still contain a break, we must frob the loop nest. */
struct nesting *
expand_start_null_loop ()
{
struct nesting *thisloop = ALLOC_NESTING ();
/* Make an entry on loop_stack for the loop we are entering. */
thisloop->desc = LOOP_NESTING;
thisloop->next = loop_stack;
thisloop->all = nesting_stack;
thisloop->depth = ++nesting_depth;
thisloop->data.loop.start_label = emit_note (NULL, NOTE_INSN_DELETED);
thisloop->data.loop.end_label = gen_label_rtx ();
thisloop->data.loop.alt_end_label = NULL_RTX;
thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
thisloop->exit_label = thisloop->data.loop.end_label;
loop_stack = thisloop;
nesting_stack = thisloop;
return thisloop;
}
/* Specify the continuation point for a loop started with
expand_start_loop_continue_elsewhere.
Use this at the point in the code to which a continue statement
should jump. */
void
expand_loop_continue_here ()
{
do_pending_stack_adjust ();
emit_note (NULL, NOTE_INSN_LOOP_CONT);
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. */
void
expand_end_loop ()
{
rtx start_label = loop_stack->data.loop.start_label;
rtx etc_note;
int eh_regions, debug_blocks;
/* 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 the loop starts with a loop exit, roll that to the end where
it will optimize together with the jump back.
If the loop presently looks like this (in pseudo-C):
LOOP_BEG
start_label:
if (test) goto end_label;
LOOP_END_TOP_COND
body;
goto start_label;
end_label:
transform it to look like:
LOOP_BEG
goto start_label;
top_label:
body;
start_label:
if (test) goto end_label;
goto top_label;
end_label:
We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
the end of the entry condtional. Without this, our lexical scan
can't tell the difference between an entry conditional and a
body conditional that exits the loop. Mistaking the two means
that we can misplace the NOTE_INSN_LOOP_CONT note, which can
screw up loop unrolling.
Things will be oh so much better when loop optimization is done
off of a proper control flow graph... */
/* Scan insns from the top of the loop looking for the END_TOP_COND note. */
eh_regions = debug_blocks = 0;
for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
if (GET_CODE (etc_note) == NOTE)
{
if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
break;
/* We must not walk into a nested loop. */
else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
{
etc_note = NULL_RTX;
break;
}
/* At the same time, scan for EH region notes, as we don't want
to scrog region nesting. This shouldn't happen, but... */
else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
eh_regions++;
else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
{
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 ();
}
/* Likewise for debug scopes. In this case we'll either (1) move
all of the notes if they are properly nested or (2) leave the
notes alone and only rotate the loop at high optimization
levels when we expect to scrog debug info. */
else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
debug_blocks++;
else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
debug_blocks--;
}
if (etc_note
&& optimize
&& eh_regions == 0
&& (debug_blocks == 0 || optimize >= 2)
&& NEXT_INSN (etc_note) != NULL_RTX
&& ! any_condjump_p (get_last_insn ()))
{
/* We found one. Move everything from START to ETC to the end
of the loop, and add a jump from the top of the loop. */
rtx top_label = gen_label_rtx ();
rtx start_move = start_label;
/* 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)) == NOTE_INSN_LOOP_CONT)
start_move = PREV_INSN (start_move);
emit_label_before (top_label, start_move);
/* Actually move the insns. If the debug scopes are nested, we
can move everything at once. Otherwise we have to move them
one by one and squeeze out the block notes. */
if (debug_blocks == 0)
reorder_insns (start_move, etc_note, get_last_insn ());
else
{
rtx insn, next_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. */
next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
if (GET_CODE (insn) == NOTE
&& (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
continue;
reorder_insns (insn, insn, get_last_insn ());
}
}
/* Add the jump from the top of the loop. */
emit_jump_insn_before (gen_jump (start_label), top_label);
emit_barrier_before (top_label);
start_label = top_label;
}
emit_jump (start_label);
emit_note (NULL, NOTE_INSN_LOOP_END);
emit_label (loop_stack->data.loop.end_label);
POPSTACK (loop_stack);
clear_last_expr ();
}
/* Finish a null loop, aka do { } while (0). */
void
expand_end_null_loop ()
{
do_pending_stack_adjust ();
emit_label (loop_stack->data.loop.end_label);
POPSTACK (loop_stack);
clear_last_expr ();
}
/* 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. */
int
expand_continue_loop (whichloop)
struct nesting *whichloop;
{
/* Emit information for branch prediction. */
rtx note;
if (flag_guess_branch_prob)
{
note = emit_note (NULL, NOTE_INSN_PREDICTION);
NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
}
clear_last_expr ();
if (whichloop == 0)
whichloop = loop_stack;
if (whichloop == 0)
return 0;
expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
NULL_RTX);
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. */
int
expand_exit_loop (whichloop)
struct nesting *whichloop;
{
clear_last_expr ();
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. */
int
expand_exit_loop_if_false (whichloop, cond)
struct nesting *whichloop;
tree cond;
{
rtx label = gen_label_rtx ();
rtx last_insn;
clear_last_expr ();
if (whichloop == 0)
whichloop = loop_stack;
if (whichloop == 0)
return 0;
/* In order to handle fixups, we actually create a conditional jump
around an 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,
NULL_RTX);
emit_label (label);
return 1;
}
/* Like expand_exit_loop_if_false except also emit a note marking
the end of the conditional. Should only be used immediately
after expand_loop_start. */
int
expand_exit_loop_top_cond (whichloop, cond)
struct nesting *whichloop;
tree cond;
{
if (! expand_exit_loop_if_false (whichloop, cond))
return 0;
emit_note (NULL, NOTE_INSN_LOOP_END_TOP_COND);
return 1;
}
/* Return nonzero if the loop nest is empty. Else return zero. */
int
stmt_loop_nest_empty ()
{
/* cfun->stmt can be NULL if we are building a call to get the
EH context for a setjmp/longjmp EH target and the current
function was a deferred inline function. */
return (cfun->stmt == NULL || loop_stack == NULL);
}
/* Return nonzero 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. */
int
preserve_subexpressions_p ()
{
rtx insn;
if (flag_expensive_optimizations)
return 1;
if (optimize == 0 || cfun == 0 || cfun->stmt == 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. */
int
expand_exit_something ()
{
struct nesting *n;
clear_last_expr ();
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.) */
void
expand_null_return ()
{
rtx last_insn;
last_insn = get_last_insn ();
/* If this function was declared to return a value, but we
didn't, clobber the return registers so that they are not
propagated live to the rest of the function. */
clobber_return_register ();
expand_null_return_1 (last_insn);
}
/* Try to guess whether the value of return means error code. */
static enum br_predictor
return_prediction (val)
rtx val;
{
/* Different heuristics for pointers and scalars. */
if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
{
/* NULL is usually not returned. */
if (val == const0_rtx)
return PRED_NULL_RETURN;
}
else
{
/* Negative return values are often used to indicate
errors. */
if (GET_CODE (val) == CONST_INT
&& INTVAL (val) < 0)
return PRED_NEGATIVE_RETURN;
/* Constant return values are also usually erors,
zero/one often mean booleans so exclude them from the
heuristics. */
if (CONSTANT_P (val)
&& (val != const0_rtx && val != const1_rtx))
return PRED_CONST_RETURN;
}
return PRED_NO_PREDICTION;
}
/* Generate RTL to return from the current function, with value VAL. */
static void
expand_value_return (val)
rtx val;
{
rtx last_insn;
rtx return_reg;
enum br_predictor pred;
if (flag_guess_branch_prob
&& (pred = return_prediction (val)) != PRED_NO_PREDICTION)
{
/* Emit information for branch prediction. */
rtx note;
note = emit_note (NULL, NOTE_INSN_PREDICTION);
NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
}
last_insn = get_last_insn ();
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));
#ifdef PROMOTE_FUNCTION_RETURN
int unsignedp = TREE_UNSIGNED (type);
enum machine_mode old_mode
= DECL_MODE (DECL_RESULT (current_function_decl));
enum machine_mode mode
= promote_mode (type, old_mode, &unsignedp, 1);
if (mode != old_mode)
val = convert_modes (mode, old_mode, val, unsignedp);
#endif
if (GET_CODE (return_reg) == PARALLEL)
emit_group_load (return_reg, val, int_size_in_bytes (type));
else
emit_move_insn (return_reg, val);
}
expand_null_return_1 (last_insn);
}
/* Output a return with no value. If LAST_INSN is nonzero,
pretend that the return takes place after LAST_INSN. */
static void
expand_null_return_1 (last_insn)
rtx last_insn;
{
rtx end_label = cleanup_label ? cleanup_label : return_label;
clear_pending_stack_adjust ();
do_pending_stack_adjust ();
clear_last_expr ();
if (end_label == 0)
end_label = return_label = gen_label_rtx ();
expand_goto_internal (NULL_TREE, end_label, last_insn);
}
/* Generate RTL to evaluate the expression RETVAL and return it
from the current function. */
void
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;
rtx result_rtl;
rtx val = 0;
tree retval_rhs;
/* 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 ();
return;
}
if (retval == error_mark_node)
{
/* Treat this like a return of no value from a function that
returns a value. */
expand_null_return ();
return;
}
else if (TREE_CODE (retval) == RESULT_DECL)
retval_rhs = retval;
else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
&& TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
retval_rhs = TREE_OPERAND (retval, 1);
else if (VOID_TYPE_P (TREE_TYPE (retval)))
/* Recognize tail-recursive call to void function. */
retval_rhs = retval;
else
retval_rhs = NULL_TREE;
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);
start_cleanup_deferral ();
expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
DECL_RESULT (current_function_decl),
TREE_OPERAND (retval_rhs, 1));
TREE_SIDE_EFFECTS (expr) = 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));
TREE_SIDE_EFFECTS (expr) = 1;
expand_return (expr);
end_cleanup_deferral ();
return;
}
result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
/* 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 (result_rtl) == REG)
{
int i;
unsigned HOST_WIDE_INT bitpos, xbitpos;
unsigned HOST_WIDE_INT big_endian_correction = 0;
unsigned HOST_WIDE_INT bytes
= int_size_in_bytes (TREE_TYPE (retval_rhs));
int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
unsigned 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;
if (bytes == 0)
{
expand_null_return ();
return;
}
/* 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. */
if (BYTES_BIG_ENDIAN
&& bytes % UNITS_PER_WORD)
big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
* BITS_PER_UNIT));
/* 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;
/* Clear the destination before we move anything into it. */
emit_move_insn (dst, CONST0_RTX (GET_MODE (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,
BLKmode);
/* 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, word_mode,
BITS_PER_WORD),
BITS_PER_WORD);
}
/* 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. */
for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
tmpmode != VOIDmode;
tmpmode = GET_MODE_WIDER_MODE (tmpmode))
/* Have we found a large enough mode? */
if (GET_MODE_SIZE (tmpmode) >= bytes)
break;
/* No suitable mode found. */
if (tmpmode == VOIDmode)
abort ();
PUT_MODE (result_rtl, tmpmode);
if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
result_reg_mode = word_mode;
else
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),
result_pseudos[i]);
if (tmpmode != result_reg_mode)
result_reg = gen_lowpart (tmpmode, result_reg);
expand_value_return (result_reg);
}
else if (retval_rhs != 0
&& !VOID_TYPE_P (TREE_TYPE (retval_rhs))
&& (GET_CODE (result_rtl) == REG
|| (GET_CODE (result_rtl) == PARALLEL)))
{
/* Calculate the return value into a temporary (usually a pseudo
reg). */
tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
val = assign_temp (nt, 0, 0, 1);
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);
}
else
{
/* 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 (result_rtl);
}
}
/* Return 1 if the end of the generated RTX is not a barrier.
This means code already compiled can drop through. */
int
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;
}
/* Attempt to optimize a potential tail recursion call into a goto.