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gcc/gcc/tree-ssa-operands.c

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/* SSA operands management for trees.
Copyright (C) 2003 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. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "flags.h"
#include "function.h"
#include "diagnostic.h"
#include "tree-flow.h"
#include "tree-inline.h"
#include "tree-pass.h"
#include "ggc.h"
#include "timevar.h"
/* Flags to describe operand properties in get_stmt_operands and helpers. */
/* By default, operands are loaded. */
#define opf_none 0
/* Operand is the target of an assignment expression or a
call-clobbered variable */
#define opf_is_def (1 << 0)
/* Operand is the target of an assignment expression. */
#define opf_kill_def (1 << 2)
/* No virtual operands should be created in the expression. This is used
when traversing ADDR_EXPR nodes which have different semantics than
other expressions. Inside an ADDR_EXPR node, the only operands that we
need to consider are indices into arrays. For instance, &a.b[i] should
generate a USE of 'i' but it should not generate a VUSE for 'a' nor a
VUSE for 'b'. */
#define opf_no_vops (1 << 1)
/* Array for building all the def operands. */
static GTY (()) varray_type build_defs;
/* Array for building all the use operands. */
static GTY (()) varray_type build_uses;
/* Array for building all the v_may_def operands. */
static GTY (()) varray_type build_v_may_defs;
/* Array for building all the vuse operands. */
static GTY (()) varray_type build_vuses;
/* Array for building all the v_must_def operands. */
static GTY (()) varray_type build_v_must_defs;
#ifdef ENABLE_CHECKING
tree check_build_stmt;
#endif
typedef struct voperands_d
{
v_may_def_optype v_may_def_ops;
vuse_optype vuse_ops;
v_must_def_optype v_must_def_ops;
} *voperands_t;
static void note_addressable (tree, stmt_ann_t);
static void get_expr_operands (tree, tree *, int, voperands_t);
static void get_asm_expr_operands (tree, voperands_t);
static void get_indirect_ref_operands (tree, tree, int, voperands_t);
static void get_call_expr_operands (tree, tree, voperands_t);
static inline void append_def (tree *, tree);
static inline void append_use (tree *, tree);
static void append_v_may_def (tree, tree, voperands_t);
static void append_v_must_def (tree, tree, voperands_t);
static void add_call_clobber_ops (tree, voperands_t);
static void add_call_read_ops (tree, voperands_t);
static void add_stmt_operand (tree *, tree, int, voperands_t);
/* Return a vector of contiguous memory of a specified size. */
static inline def_optype
allocate_def_optype (unsigned num)
{
def_optype def_ops;
unsigned size;
size = sizeof (struct def_optype_d) + sizeof (tree *) * (num - 1);
def_ops = ggc_alloc (size);
def_ops->num_defs = num;
return def_ops;
}
static inline use_optype
allocate_use_optype (unsigned num)
{
use_optype use_ops;
unsigned size;
size = sizeof (struct use_optype_d) + sizeof (tree *) * (num - 1);
use_ops = ggc_alloc (size);
use_ops->num_uses = num;
return use_ops;
}
static inline v_may_def_optype
allocate_v_may_def_optype (unsigned num)
{
v_may_def_optype v_may_def_ops;
unsigned size;
size = sizeof (struct v_may_def_optype_d) + sizeof (tree) * ((num * 2) - 1);
v_may_def_ops = ggc_alloc (size);
v_may_def_ops->num_v_may_defs = num;
return v_may_def_ops;
}
static inline vuse_optype
allocate_vuse_optype (unsigned num)
{
vuse_optype vuse_ops;
unsigned size;
size = sizeof (struct vuse_optype_d) + sizeof (tree) * (num - 1);
vuse_ops = ggc_alloc (size);
vuse_ops->num_vuses = num;
return vuse_ops;
}
static inline v_must_def_optype
allocate_v_must_def_optype (unsigned num)
{
v_must_def_optype v_must_def_ops;
unsigned size;
size = sizeof (struct v_must_def_optype_d) + sizeof (tree *) * (num - 1);
v_must_def_ops = ggc_alloc (size);
v_must_def_ops->num_v_must_defs = num;
return v_must_def_ops;
}
static inline void
free_uses (use_optype *uses, bool dealloc)
{
if (*uses)
{
if (dealloc)
ggc_free (*uses);
*uses = NULL;
}
}
static inline void
free_defs (def_optype *defs, bool dealloc)
{
if (*defs)
{
if (dealloc)
ggc_free (*defs);
*defs = NULL;
}
}
static inline void
free_vuses (vuse_optype *vuses, bool dealloc)
{
if (*vuses)
{
if (dealloc)
ggc_free (*vuses);
*vuses = NULL;
}
}
static inline void
free_v_may_defs (v_may_def_optype *v_may_defs, bool dealloc)
{
if (*v_may_defs)
{
if (dealloc)
ggc_free (*v_may_defs);
*v_may_defs = NULL;
}
}
static inline void
free_v_must_defs (v_must_def_optype *v_must_defs, bool dealloc)
{
if (*v_must_defs)
{
if (dealloc)
ggc_free (*v_must_defs);
*v_must_defs = NULL;
}
}
void
remove_vuses (tree stmt)
{
stmt_ann_t ann;
ann = stmt_ann (stmt);
if (ann)
free_vuses (&(ann->vuse_ops), true);
}
void
remove_v_may_defs (tree stmt)
{
stmt_ann_t ann;
ann = stmt_ann (stmt);
if (ann)
free_v_may_defs (&(ann->v_may_def_ops), true);
}
void
remove_v_must_defs (tree stmt)
{
stmt_ann_t ann;
ann = stmt_ann (stmt);
if (ann)
free_v_must_defs (&(ann->v_must_def_ops), true);
}
void
init_ssa_operands (void)
{
VARRAY_TREE_PTR_INIT (build_defs, 5, "build defs");
VARRAY_TREE_PTR_INIT (build_uses, 10, "build uses");
VARRAY_TREE_INIT (build_v_may_defs, 10, "build v_may_defs");
VARRAY_TREE_INIT (build_vuses, 10, "build vuses");
VARRAY_TREE_INIT (build_v_must_defs, 10, "build v_must_defs");
}
void
fini_ssa_operands (void)
{
}
static void
finalize_ssa_defs (tree stmt)
{
unsigned num, x;
stmt_ann_t ann;
def_optype def_ops;
num = VARRAY_ACTIVE_SIZE (build_defs);
if (num == 0)
return;
#ifdef ENABLE_CHECKING
/* There should only be a single real definition per assignment. */
if (TREE_CODE (stmt) == MODIFY_EXPR && num > 1)
abort ();
#endif
def_ops = allocate_def_optype (num);
for (x = 0; x < num ; x++)
def_ops->defs[x].def = VARRAY_TREE_PTR (build_defs, x);
VARRAY_POP_ALL (build_defs);
ann = stmt_ann (stmt);
ann->def_ops = def_ops;
}
static void
finalize_ssa_uses (tree stmt)
{
unsigned num, x;
use_optype use_ops;
stmt_ann_t ann;
num = VARRAY_ACTIVE_SIZE (build_uses);
if (num == 0)
return;
#ifdef ENABLE_CHECKING
{
unsigned x;
/* If the pointer to the operand is the statement itself, something is
wrong. It means that we are pointing to a local variable (the
initial call to get_stmt_operands does not pass a pointer to a
statement). */
for (x = 0; x < num; x++)
if (*(VARRAY_TREE_PTR (build_uses, x)) == stmt)
abort ();
}
#endif
use_ops = allocate_use_optype (num);
for (x = 0; x < num ; x++)
use_ops->uses[x].use = VARRAY_TREE_PTR (build_uses, x);
VARRAY_POP_ALL (build_uses);
ann = stmt_ann (stmt);
ann->use_ops = use_ops;
}
static void
finalize_ssa_v_may_defs (tree stmt)
{
unsigned num, x;
v_may_def_optype v_may_def_ops;
stmt_ann_t ann;
num = VARRAY_ACTIVE_SIZE (build_v_may_defs);
if (num == 0)
return;
#ifdef ENABLE_CHECKING
/* V_MAY_DEFs must be entered in pairs of result/uses. */
if (num % 2 != 0)
abort();
#endif
v_may_def_ops = allocate_v_may_def_optype (num / 2);
for (x = 0; x < num; x++)
v_may_def_ops->v_may_defs[x] = VARRAY_TREE (build_v_may_defs, x);
VARRAY_CLEAR (build_v_may_defs);
ann = stmt_ann (stmt);
ann->v_may_def_ops = v_may_def_ops;
}
static inline void
finalize_ssa_vuses (tree stmt)
{
unsigned num, x;
stmt_ann_t ann;
vuse_optype vuse_ops;
v_may_def_optype v_may_defs;
#ifdef ENABLE_CHECKING
if (VARRAY_ACTIVE_SIZE (build_v_may_defs) > 0)
{
fprintf (stderr, "Please finalize V_MAY_DEFs before finalize VUSES.\n");
abort ();
}
#endif
num = VARRAY_ACTIVE_SIZE (build_vuses);
if (num == 0)
return;
/* Remove superfluous VUSE operands. If the statement already has a
V_MAY_DEF operation for a variable 'a', then a VUSE for 'a' is not
needed because V_MAY_DEFs imply a VUSE of the variable. For instance,
suppose that variable 'a' is aliased:
# VUSE <a_2>
# a_3 = V_MAY_DEF <a_2>
a = a + 1;
The VUSE <a_2> is superfluous because it is implied by the V_MAY_DEF
operation. */
ann = stmt_ann (stmt);
v_may_defs = V_MAY_DEF_OPS (ann);
if (NUM_V_MAY_DEFS (v_may_defs) > 0)
{
size_t i, j;
for (i = 0; i < VARRAY_ACTIVE_SIZE (build_vuses); i++)
{
bool found = false;
for (j = 0; j < NUM_V_MAY_DEFS (v_may_defs); j++)
{
tree vuse_var, v_may_def_var;
tree vuse = VARRAY_TREE (build_vuses, i);
tree v_may_def = V_MAY_DEF_OP (v_may_defs, j);
if (TREE_CODE (vuse) == SSA_NAME)
vuse_var = SSA_NAME_VAR (vuse);
else
vuse_var = vuse;
if (TREE_CODE (v_may_def) == SSA_NAME)
v_may_def_var = SSA_NAME_VAR (v_may_def);
else
v_may_def_var = v_may_def;
if (vuse_var == v_may_def_var)
{
found = true;
break;
}
}
/* If we found a useless VUSE operand, remove it from the
operand array by replacing it with the last active element
in the operand array (unless the useless VUSE was the
last operand, in which case we simply remove it. */
if (found)
{
if (i != VARRAY_ACTIVE_SIZE (build_vuses) - 1)
{
VARRAY_TREE (build_vuses, i)
= VARRAY_TREE (build_vuses,
VARRAY_ACTIVE_SIZE (build_vuses) - 1);
}
VARRAY_POP (build_vuses);
/* We want to rescan the element at this index, unless
this was the last element, in which case the loop
terminates. */
i--;
}
}
}
num = VARRAY_ACTIVE_SIZE (build_vuses);
/* We could have reduced the size to zero now, however. */
if (num == 0)
return;
vuse_ops = allocate_vuse_optype (num);
for (x = 0; x < num; x++)
vuse_ops->vuses[x] = VARRAY_TREE (build_vuses, x);
VARRAY_CLEAR (build_vuses);
ann->vuse_ops = vuse_ops;
}
static void
finalize_ssa_v_must_defs (tree stmt)
{
unsigned num, x;
stmt_ann_t ann;
v_must_def_optype v_must_def_ops;
num = VARRAY_ACTIVE_SIZE (build_v_must_defs);
if (num == 0)
return;
#ifdef ENABLE_CHECKING
/* There should only be a single V_MUST_DEF per assignment. */
if (TREE_CODE (stmt) == MODIFY_EXPR && num > 1)
abort ();
#endif
v_must_def_ops = allocate_v_must_def_optype (num);
for (x = 0; x < num ; x++)
v_must_def_ops->v_must_defs[x] = VARRAY_TREE (build_v_must_defs, x);
VARRAY_POP_ALL (build_v_must_defs);
ann = stmt_ann (stmt);
ann->v_must_def_ops = v_must_def_ops;
}
extern void
finalize_ssa_stmt_operands (tree stmt)
{
#ifdef ENABLE_CHECKING
if (check_build_stmt == NULL)
abort();
#endif
finalize_ssa_defs (stmt);
finalize_ssa_uses (stmt);
finalize_ssa_v_must_defs (stmt);
finalize_ssa_v_may_defs (stmt);
finalize_ssa_vuses (stmt);
#ifdef ENABLE_CHECKING
check_build_stmt = NULL;
#endif
}
extern void
verify_start_operands (tree stmt ATTRIBUTE_UNUSED)
{
#ifdef ENABLE_CHECKING
if (VARRAY_ACTIVE_SIZE (build_defs) > 0
|| VARRAY_ACTIVE_SIZE (build_uses) > 0
|| VARRAY_ACTIVE_SIZE (build_vuses) > 0
|| VARRAY_ACTIVE_SIZE (build_v_may_defs) > 0
|| VARRAY_ACTIVE_SIZE (build_v_must_defs) > 0)
abort ();
if (check_build_stmt != NULL)
abort();
check_build_stmt = stmt;
#endif
}
/* Add DEF_P to the list of pointers to operands defined by STMT. */
static inline void
append_def (tree *def_p, tree stmt ATTRIBUTE_UNUSED)
{
#ifdef ENABLE_CHECKING
if (check_build_stmt != stmt)
abort();
#endif
VARRAY_PUSH_TREE_PTR (build_defs, def_p);
}
/* Add USE_P to the list of pointers to operands used by STMT. */
static inline void
append_use (tree *use_p, tree stmt ATTRIBUTE_UNUSED)
{
#ifdef ENABLE_CHECKING
if (check_build_stmt != stmt)
abort();
#endif
VARRAY_PUSH_TREE_PTR (build_uses, use_p);
}
/* Add a new virtual def for variable VAR to statement STMT. If PREV_VOPS
is not NULL, the existing entries are preserved and no new entries are
added here. This is done to preserve the SSA numbering of virtual
operands. */
static void
append_v_may_def (tree var, tree stmt, voperands_t prev_vops)
{
stmt_ann_t ann;
size_t i;
tree result, source;
#ifdef ENABLE_CHECKING
if (check_build_stmt != stmt)
abort();
#endif
ann = stmt_ann (stmt);
/* Don't allow duplicate entries. */
for (i = 0; i < VARRAY_ACTIVE_SIZE (build_v_may_defs); i += 2)
{
tree result = VARRAY_TREE (build_v_may_defs, i);
if (var == result
|| (TREE_CODE (result) == SSA_NAME
&& var == SSA_NAME_VAR (result)))
return;
}
/* If the statement already had virtual definitions, see if any of the
existing V_MAY_DEFs matches VAR. If so, re-use it, otherwise add a new
V_MAY_DEF for VAR. */
result = NULL_TREE;
source = NULL_TREE;
if (prev_vops)
for (i = 0; i < NUM_V_MAY_DEFS (prev_vops->v_may_def_ops); i++)
{
result = V_MAY_DEF_RESULT (prev_vops->v_may_def_ops, i);
if (result == var
|| (TREE_CODE (result) == SSA_NAME
&& SSA_NAME_VAR (result) == var))
{
source = V_MAY_DEF_OP (prev_vops->v_may_def_ops, i);
break;
}
}
/* If no previous V_MAY_DEF operand was found for VAR, create one now. */
if (source == NULL_TREE)
{
result = var;
source = var;
}
VARRAY_PUSH_TREE (build_v_may_defs, result);
VARRAY_PUSH_TREE (build_v_may_defs, source);
}
/* Add VAR to the list of virtual uses for STMT. If PREV_VOPS
is not NULL, the existing entries are preserved and no new entries are
added here. This is done to preserve the SSA numbering of virtual
operands. */
static void
append_vuse (tree var, tree stmt, voperands_t prev_vops)
{
stmt_ann_t ann;
size_t i;
bool found;
tree vuse;
#ifdef ENABLE_CHECKING
if (check_build_stmt != stmt)
abort();
#endif
ann = stmt_ann (stmt);
/* Don't allow duplicate entries. */
for (i = 0; i < VARRAY_ACTIVE_SIZE (build_vuses); i++)
{
tree vuse_var = VARRAY_TREE (build_vuses, i);
if (var == vuse_var
|| (TREE_CODE (vuse_var) == SSA_NAME
&& var == SSA_NAME_VAR (vuse_var)))
return;
}
/* If the statement already had virtual uses, see if any of the
existing VUSEs matches VAR. If so, re-use it, otherwise add a new
VUSE for VAR. */
found = false;
vuse = NULL_TREE;
if (prev_vops)
for (i = 0; i < NUM_VUSES (prev_vops->vuse_ops); i++)
{
vuse = VUSE_OP (prev_vops->vuse_ops, i);
if (vuse == var
|| (TREE_CODE (vuse) == SSA_NAME
&& SSA_NAME_VAR (vuse) == var))
{
found = true;
break;
}
}
/* If VAR existed already in PREV_VOPS, re-use it. */
if (found)
var = vuse;
VARRAY_PUSH_TREE (build_vuses, var);
}
/* Add VAR to the list of virtual must definitions for STMT. If PREV_VOPS
is not NULL, the existing entries are preserved and no new entries are
added here. This is done to preserve the SSA numbering of virtual
operands. */
static void
append_v_must_def (tree var, tree stmt, voperands_t prev_vops)
{
stmt_ann_t ann;
size_t i;
bool found;
tree v_must_def;
#ifdef ENABLE_CHECKING
if (check_build_stmt != stmt)
abort();
#endif
ann = stmt_ann (stmt);
/* Don't allow duplicate entries. */
for (i = 0; i < VARRAY_ACTIVE_SIZE (build_v_must_defs); i++)
{
tree v_must_def_var = VARRAY_TREE (build_v_must_defs, i);
if (var == v_must_def_var
|| (TREE_CODE (v_must_def_var) == SSA_NAME
&& var == SSA_NAME_VAR (v_must_def_var)))
return;
}
/* If the statement already had virtual must defs, see if any of the
existing V_MUST_DEFs matches VAR. If so, re-use it, otherwise add a new
V_MUST_DEF for VAR. */
found = false;
v_must_def = NULL_TREE;
if (prev_vops)
for (i = 0; i < NUM_V_MUST_DEFS (prev_vops->v_must_def_ops); i++)
{
v_must_def = V_MUST_DEF_OP (prev_vops->v_must_def_ops, i);
if (v_must_def == var
|| (TREE_CODE (v_must_def) == SSA_NAME
&& SSA_NAME_VAR (v_must_def) == var))
{
found = true;
break;
}
}
/* If VAR existed already in PREV_VOPS, re-use it. */
if (found)
var = v_must_def;
VARRAY_PUSH_TREE (build_v_must_defs, var);
}
/* External entry point which by-passes the previous vops mechanism. */
void
add_vuse (tree var, tree stmt)
{
append_vuse (var, stmt, NULL);
}
/* Get the operands of statement STMT. Note that repeated calls to
get_stmt_operands for the same statement will do nothing until the
statement is marked modified by a call to modify_stmt(). */
void
get_stmt_operands (tree stmt)
{
enum tree_code code;
stmt_ann_t ann;
struct voperands_d prev_vops;
#if defined ENABLE_CHECKING
/* The optimizers cannot handle statements that are nothing but a
_DECL. This indicates a bug in the gimplifier. */
if (SSA_VAR_P (stmt))
abort ();
#endif
/* Ignore error statements. */
if (TREE_CODE (stmt) == ERROR_MARK)
return;
ann = get_stmt_ann (stmt);
/* If the statement has not been modified, the operands are still valid. */
if (!ann->modified)
return;
timevar_push (TV_TREE_OPS);
/* Initially assume that the statement has no volatile operands, nor
makes aliased loads or stores. */
ann->has_volatile_ops = false;
ann->makes_aliased_stores = false;
ann->makes_aliased_loads = false;
/* Remove any existing operands as they will be scanned again. */
free_defs (&(ann->def_ops), true);
free_uses (&(ann->use_ops), true);
/* Before removing existing virtual operands, save them in PREV_VOPS so
that we can re-use their SSA versions. */
prev_vops.v_may_def_ops = V_MAY_DEF_OPS (ann);
prev_vops.vuse_ops = VUSE_OPS (ann);
prev_vops.v_must_def_ops = V_MUST_DEF_OPS (ann);
/* Don't free the previous values to memory since we're still using them. */
free_v_may_defs (&(ann->v_may_def_ops), false);
free_vuses (&(ann->vuse_ops), false);
free_v_must_defs (&(ann->v_must_def_ops), false);
start_ssa_stmt_operands (stmt);
code = TREE_CODE (stmt);
switch (code)
{
case MODIFY_EXPR:
get_expr_operands (stmt, &TREE_OPERAND (stmt, 1), opf_none, &prev_vops);
if (TREE_CODE (TREE_OPERAND (stmt, 0)) == ARRAY_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == ARRAY_RANGE_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == COMPONENT_REF
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == REALPART_EXPR
|| TREE_CODE (TREE_OPERAND (stmt, 0)) == IMAGPART_EXPR
/* Use a V_MAY_DEF if the RHS might throw, as the LHS won't be
modified in that case. FIXME we should represent somehow
that it is killed on the fallthrough path. */
|| tree_could_throw_p (TREE_OPERAND (stmt, 1)))
get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_is_def,
&prev_vops);
else
get_expr_operands (stmt, &TREE_OPERAND (stmt, 0),
opf_is_def | opf_kill_def, &prev_vops);
break;
case COND_EXPR:
get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_none, &prev_vops);
break;
case SWITCH_EXPR:
get_expr_operands (stmt, &SWITCH_COND (stmt), opf_none, &prev_vops);
break;
case ASM_EXPR:
get_asm_expr_operands (stmt, &prev_vops);
break;
case RETURN_EXPR:
get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_none, &prev_vops);
break;
case GOTO_EXPR:
get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_none, &prev_vops);
break;
case LABEL_EXPR:
get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_none, &prev_vops);
break;
/* These nodes contain no variable references. */
case BIND_EXPR:
case CASE_LABEL_EXPR:
case TRY_CATCH_EXPR:
case TRY_FINALLY_EXPR:
case EH_FILTER_EXPR:
case CATCH_EXPR:
case RESX_EXPR:
break;
default:
/* Notice that if get_expr_operands tries to use &STMT as the operand
pointer (which may only happen for USE operands), we will abort in
append_use. This default will handle statements like empty
statements, or CALL_EXPRs that may appear on the RHS of a statement
or as statements themselves. */
get_expr_operands (stmt, &stmt, opf_none, &prev_vops);
break;
}
finalize_ssa_stmt_operands (stmt);
/* Now free the previous virtual ops to memory. */
free_v_may_defs (&(prev_vops.v_may_def_ops), true);
free_vuses (&(prev_vops.vuse_ops), true);
free_v_must_defs (&(prev_vops.v_must_def_ops), true);
/* Clear the modified bit for STMT. Subsequent calls to
get_stmt_operands for this statement will do nothing until the
statement is marked modified by a call to modify_stmt(). */
ann->modified = 0;
timevar_pop (TV_TREE_OPS);
}
/* Recursively scan the expression pointed by EXPR_P in statement STMT.
FLAGS is one of the OPF_* constants modifying how to interpret the
operands found. PREV_VOPS is as in append_v_may_def and append_vuse. */
static void
get_expr_operands (tree stmt, tree *expr_p, int flags, voperands_t prev_vops)
{
enum tree_code code;
char class;
tree expr = *expr_p;
if (expr == NULL || expr == error_mark_node)
return;
code = TREE_CODE (expr);
class = TREE_CODE_CLASS (code);
switch (code)
{
case ADDR_EXPR:
/* We could have the address of a component, array member,
etc which has interesting variable references. */
/* Taking the address of a variable does not represent a
reference to it, but the fact that STMT takes its address will be
of interest to some passes (e.g. alias resolution). */
add_stmt_operand (expr_p, stmt, 0, NULL);
/* If the address is invariant, there may be no interesting variable
references inside. */
if (is_gimple_min_invariant (expr))
return;
/* There should be no VUSEs created, since the referenced objects are
not really accessed. The only operands that we should find here
are ARRAY_REF indices which will always be real operands (GIMPLE
does not allow non-registers as array indices). */
flags |= opf_no_vops;
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags, prev_vops);
return;
case SSA_NAME:
case VAR_DECL:
case PARM_DECL:
case RESULT_DECL:
/* If we found a variable, add it to DEFS or USES depending
on the operand flags. */
add_stmt_operand (expr_p, stmt, flags, prev_vops);
return;
case INDIRECT_REF:
get_indirect_ref_operands (stmt, expr, flags, prev_vops);
return;
case ARRAY_REF:
case ARRAY_RANGE_REF:
/* Treat array references as references to the virtual variable
representing the array. The virtual variable for an ARRAY_REF
is the VAR_DECL for the array. */
/* Add the virtual variable for the ARRAY_REF to VDEFS or VUSES
according to the value of IS_DEF. Recurse if the LHS of the
ARRAY_REF node is not a regular variable. */
if (SSA_VAR_P (TREE_OPERAND (expr, 0)))
add_stmt_operand (expr_p, stmt, flags, prev_vops);
else
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags, prev_vops);
get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none, prev_vops);
get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none, prev_vops);
get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_none, prev_vops);
return;
case COMPONENT_REF:
case REALPART_EXPR:
case IMAGPART_EXPR:
/* Similarly to arrays, references to compound variables (complex
types and structures/unions) are globbed.
FIXME: This means that
a.x = 6;
a.y = 7;
foo (a.x, a.y);
will not be constant propagated because the two partial
definitions to 'a' will kill each other. Note that SRA may be
able to fix this problem if 'a' can be scalarized. */
/* If the LHS of the compound reference is not a regular variable,
recurse to keep looking for more operands in the subexpression. */
if (SSA_VAR_P (TREE_OPERAND (expr, 0)))
add_stmt_operand (expr_p, stmt, flags, prev_vops);
else
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags, prev_vops);
if (code == COMPONENT_REF)
get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none, prev_vops);
return;
case WITH_SIZE_EXPR:
/* WITH_SIZE_EXPR is a pass-through reference to its first argument,
and an rvalue reference to its second argument. */
get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none, prev_vops);
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags, prev_vops);
return;
case CALL_EXPR:
get_call_expr_operands (stmt, expr, prev_vops);
return;
case MODIFY_EXPR:
{
int subflags;
tree op;
get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none, prev_vops);
op = TREE_OPERAND (expr, 0);
if (TREE_CODE (op) == WITH_SIZE_EXPR)
op = TREE_OPERAND (expr, 0);
if (TREE_CODE (op) == ARRAY_REF
|| TREE_CODE (op) == ARRAY_RANGE_REF
|| TREE_CODE (op) == COMPONENT_REF
|| TREE_CODE (op) == REALPART_EXPR
|| TREE_CODE (op) == IMAGPART_EXPR)
subflags = opf_is_def;
else
subflags = opf_is_def | opf_kill_def;
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), subflags, prev_vops);
return;
}
case CONSTRUCTOR:
{
/* General aggregate CONSTRUCTORs have been decomposed, but they
are still in use as the COMPLEX_EXPR equivalent for vectors. */
tree t;
for (t = TREE_OPERAND (expr, 0); t ; t = TREE_CHAIN (t))
get_expr_operands (stmt, &TREE_VALUE (t), opf_none, prev_vops);
return;
}
case TRUTH_NOT_EXPR:
case BIT_FIELD_REF:
case VIEW_CONVERT_EXPR:
do_unary:
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags, prev_vops);
return;
case TRUTH_AND_EXPR:
case TRUTH_OR_EXPR:
case TRUTH_XOR_EXPR:
case COMPOUND_EXPR:
case OBJ_TYPE_REF:
do_binary:
{
tree op0 = TREE_OPERAND (expr, 0);
tree op1 = TREE_OPERAND (expr, 1);
/* If it would be profitable to swap the operands, then do so to
canonicalize the statement, enabling better optimization.
By placing canonicalization of such expressions here we
transparently keep statements in canonical form, even
when the statement is modified. */
if (tree_swap_operands_p (op0, op1, false))
{
/* For relationals we need to swap the operands
and change the code. */
if (code == LT_EXPR
|| code == GT_EXPR
|| code == LE_EXPR
|| code == GE_EXPR)
{
TREE_SET_CODE (expr, swap_tree_comparison (code));
TREE_OPERAND (expr, 0) = op1;
TREE_OPERAND (expr, 1) = op0;
}
/* For a commutative operator we can just swap the operands. */
else if (commutative_tree_code (code))
{
TREE_OPERAND (expr, 0) = op1;
TREE_OPERAND (expr, 1) = op0;
}
}
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags, prev_vops);
get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags, prev_vops);
return;
}
case BLOCK:
case FUNCTION_DECL:
case EXC_PTR_EXPR:
case FILTER_EXPR:
case LABEL_DECL:
/* Expressions that make no memory references. */
return;
default:
if (class == '1')
goto do_unary;
if (class == '2' || class == '<')
goto do_binary;
if (class == 'c' || class == 't')
return;
}
/* If we get here, something has gone wrong. */
fprintf (stderr, "unhandled expression in get_expr_operands():\n");
debug_tree (expr);
fputs ("\n", stderr);
abort ();
}
/* Scan operands in ASM_EXPR STMT. PREV_VOPS is as in append_v_may_def and
append_vuse. */
static void
get_asm_expr_operands (tree stmt, voperands_t prev_vops)
{
int noutputs = list_length (ASM_OUTPUTS (stmt));
const char **oconstraints
= (const char **) alloca ((noutputs) * sizeof (const char *));
int i;
tree link;
const char *constraint;
bool allows_mem, allows_reg, is_inout;
stmt_ann_t s_ann = stmt_ann (stmt);
for (i=0, link = ASM_OUTPUTS (stmt); link; ++i, link = TREE_CHAIN (link))
{
oconstraints[i] = constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
parse_output_constraint (&constraint, i, 0, 0,
&allows_mem, &allows_reg, &is_inout);
#if defined ENABLE_CHECKING
/* This should have been split in gimplify_asm_expr. */
if (allows_reg && is_inout)
abort ();
#endif
/* Memory operands are addressable. Note that STMT needs the
address of this operand. */
if (!allows_reg && allows_mem)
{
tree t = get_base_address (TREE_VALUE (link));
if (t && DECL_P (t))
note_addressable (t, s_ann);
}
get_expr_operands (stmt, &TREE_VALUE (link), opf_is_def, prev_vops);
}
for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
{
constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
parse_input_constraint (&constraint, 0, 0, noutputs, 0,
oconstraints, &allows_mem, &allows_reg);
/* Memory operands are addressable. Note that STMT needs the
address of this operand. */
if (!allows_reg && allows_mem)
{
tree t = get_base_address (TREE_VALUE (link));
if (t && DECL_P (t))
note_addressable (t, s_ann);
}
get_expr_operands (stmt, &TREE_VALUE (link), 0, prev_vops);
}
/* Clobber memory for asm ("" : : : "memory"); */
for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
{
size_t i;
/* Clobber all call-clobbered variables (or .GLOBAL_VAR if we
decided to group them). */
if (global_var)
add_stmt_operand (&global_var, stmt, opf_is_def, prev_vops);
else
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i,
{
tree var = referenced_var (i);
add_stmt_operand (&var, stmt, opf_is_def, prev_vops);
});
/* Now clobber all addressables. */
EXECUTE_IF_SET_IN_BITMAP (addressable_vars, 0, i,
{
tree var = referenced_var (i);
add_stmt_operand (&var, stmt, opf_is_def, prev_vops);
});
break;
}
}
/* A subroutine of get_expr_operands to handle INDIRECT_REF. */
static void
get_indirect_ref_operands (tree stmt, tree expr, int flags,
voperands_t prev_vops)
{
tree *pptr = &TREE_OPERAND (expr, 0);
tree ptr = *pptr;
if (SSA_VAR_P (ptr))
{
struct ptr_info_def *pi = NULL;
/* If PTR has flow-sensitive points-to information, use it. */
if (TREE_CODE (ptr) == SSA_NAME
&& (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
&& pi->name_mem_tag)
{
/* PTR has its own memory tag. Use it. */
add_stmt_operand (&pi->name_mem_tag, stmt, flags, prev_vops);
}
else
{
/* If PTR is not an SSA_NAME or it doesn't have a name
tag, use its type memory tag. */
var_ann_t ann;
/* If we are emitting debugging dumps, display a warning if
PTR is an SSA_NAME with no flow-sensitive alias
information. That means that we may need to compute
aliasing again. */
if (dump_file
&& TREE_CODE (ptr) == SSA_NAME
&& pi == NULL)
{
fprintf (dump_file,
"NOTE: no flow-sensitive alias info for ");
print_generic_expr (dump_file, ptr, dump_flags);
fprintf (dump_file, " in ");
print_generic_stmt (dump_file, stmt, dump_flags);
}
if (TREE_CODE (ptr) == SSA_NAME)
ptr = SSA_NAME_VAR (ptr);
ann = var_ann (ptr);
if (ann->type_mem_tag)
add_stmt_operand (&ann->type_mem_tag, stmt, flags, prev_vops);
}
}
/* If a constant is used as a pointer, we can't generate a real
operand for it but we mark the statement volatile to prevent
optimizations from messing things up. */
else if (TREE_CODE (ptr) == INTEGER_CST)
{
stmt_ann (stmt)->has_volatile_ops = true;
return;
}
/* Everything else *should* have been folded elsewhere, but users
are smarter than we in finding ways to write invalid code. We
cannot just abort here. If we were absolutely certain that we
do handle all valid cases, then we could just do nothing here.
That seems optimistic, so attempt to do something logical... */
else if ((TREE_CODE (ptr) == PLUS_EXPR || TREE_CODE (ptr) == MINUS_EXPR)
&& TREE_CODE (TREE_OPERAND (ptr, 0)) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (ptr, 1)) == INTEGER_CST)
{
/* Make sure we know the object is addressable. */
pptr = &TREE_OPERAND (ptr, 0);
add_stmt_operand (pptr, stmt, 0, NULL);
/* Mark the object itself with a VUSE. */
pptr = &TREE_OPERAND (*pptr, 0);
get_expr_operands (stmt, pptr, flags, prev_vops);
return;
}
/* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
else
abort ();
/* Add a USE operand for the base pointer. */
get_expr_operands (stmt, pptr, opf_none, prev_vops);
}
/* A subroutine of get_expr_operands to handle CALL_EXPR. */
static void
get_call_expr_operands (tree stmt, tree expr, voperands_t prev_vops)
{
tree op;
int call_flags = call_expr_flags (expr);
/* Find uses in the called function. */
get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_none, prev_vops);
for (op = TREE_OPERAND (expr, 1); op; op = TREE_CHAIN (op))
get_expr_operands (stmt, &TREE_VALUE (op), opf_none, prev_vops);
get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none, prev_vops);
if (bitmap_first_set_bit (call_clobbered_vars) >= 0)
{
/* A 'pure' or a 'const' functions never call clobber anything.
A 'noreturn' function might, but since we don't return anyway
there is no point in recording that. */
if (!(call_flags
& (ECF_PURE | ECF_CONST | ECF_NORETURN)))
add_call_clobber_ops (stmt, prev_vops);
else if (!(call_flags & (ECF_CONST | ECF_NORETURN)))
add_call_read_ops (stmt, prev_vops);
}
}
/* Add *VAR_P to the appropriate operand array of STMT. FLAGS is as in
get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
the statement's real operands, otherwise it is added to virtual
operands.
PREV_VOPS is used when adding virtual operands to statements that
already had them (See append_v_may_def and append_vuse). */
static void
add_stmt_operand (tree *var_p, tree stmt, int flags, voperands_t prev_vops)
{
bool is_real_op;
tree var, sym;
stmt_ann_t s_ann;
var_ann_t v_ann;
var = *var_p;
STRIP_NOPS (var);
s_ann = stmt_ann (stmt);
/* If the operand is an ADDR_EXPR, add its operand to the list of
variables that have had their address taken in this statement. */
if (TREE_CODE (var) == ADDR_EXPR)
{
note_addressable (TREE_OPERAND (var, 0), s_ann);
return;
}
/* If the original variable is not a scalar, it will be added to the list
of virtual operands. In that case, use its base symbol as the virtual
variable representing it. */
is_real_op = is_gimple_reg (var);
if (!is_real_op && !DECL_P (var))
var = get_virtual_var (var);
/* If VAR is not a variable that we care to optimize, do nothing. */
if (var == NULL_TREE || !SSA_VAR_P (var))
return;
sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
v_ann = var_ann (sym);
/* Don't expose volatile variables to the optimizers. */
if (TREE_THIS_VOLATILE (sym))
{
s_ann->has_volatile_ops = true;
return;
}
if (is_real_op)
{
/* The variable is a GIMPLE register. Add it to real operands. */
if (flags & opf_is_def)
append_def (var_p, stmt);
else
append_use (var_p, stmt);
}
else
{
varray_type aliases;
/* The variable is not a GIMPLE register. Add it (or its aliases) to
virtual operands, unless the caller has specifically requested
not to add virtual operands (used when adding operands inside an
ADDR_EXPR expression). */
if (flags & opf_no_vops)
return;
aliases = v_ann->may_aliases;
if (aliases == NULL)
{
/* The variable is not aliased or it is an alias tag. */
if (flags & opf_is_def)
{
if (v_ann->is_alias_tag)
{
/* Alias tagged vars get regular V_MAY_DEF */
s_ann->makes_aliased_stores = 1;
append_v_may_def (var, stmt, prev_vops);
}
else if ((flags & opf_kill_def)
&& v_ann->mem_tag_kind == NOT_A_TAG)
/* V_MUST_DEF for non-aliased non-GIMPLE register
variable definitions. Avoid memory tags. */
append_v_must_def (var, stmt, prev_vops);
else
/* Call-clobbered variables & memory tags get
V_MAY_DEF */
append_v_may_def (var, stmt, prev_vops);
}
else
{
append_vuse (var, stmt, prev_vops);
if (v_ann->is_alias_tag)
s_ann->makes_aliased_loads = 1;
}
}
else
{
size_t i;
/* The variable is aliased. Add its aliases to the virtual
operands. */
#if defined ENABLE_CHECKING
if (VARRAY_ACTIVE_SIZE (aliases) == 0)
abort ();
#endif
if (flags & opf_is_def)
{
/* If the variable is also an alias tag, add a virtual
operand for it, otherwise we will miss representing
references to the members of the variable's alias set.
This fixes the bug in gcc.c-torture/execute/20020503-1.c. */
if (v_ann->is_alias_tag)
append_v_may_def (var, stmt, prev_vops);
for (i = 0; i < VARRAY_ACTIVE_SIZE (aliases); i++)
append_v_may_def (VARRAY_TREE (aliases, i), stmt, prev_vops);
s_ann->makes_aliased_stores = 1;
}
else
{
if (v_ann->is_alias_tag)
append_vuse (var, stmt, prev_vops);
for (i = 0; i < VARRAY_ACTIVE_SIZE (aliases); i++)
append_vuse (VARRAY_TREE (aliases, i), stmt, prev_vops);
s_ann->makes_aliased_loads = 1;
}
}
}
}
/* Record that VAR had its address taken in the statement with annotations
S_ANN. */
static void
note_addressable (tree var, stmt_ann_t s_ann)
{
var = get_base_address (var);
if (var && SSA_VAR_P (var))
{
if (s_ann->addresses_taken == NULL)
s_ann->addresses_taken = BITMAP_GGC_ALLOC ();
bitmap_set_bit (s_ann->addresses_taken, var_ann (var)->uid);
}
}
/* Add clobbering definitions for .GLOBAL_VAR or for each of the call
clobbered variables in the function. */
static void
add_call_clobber_ops (tree stmt, voperands_t prev_vops)
{
/* Functions that are not const, pure or never return may clobber
call-clobbered variables. */
stmt_ann (stmt)->makes_clobbering_call = true;
/* If we had created .GLOBAL_VAR earlier, use it. Otherwise, add
a V_MAY_DEF operand for every call clobbered variable. See
compute_may_aliases for the heuristic used to decide whether
to create .GLOBAL_VAR or not. */
if (global_var)
add_stmt_operand (&global_var, stmt, opf_is_def, prev_vops);
else
{
size_t i;
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i,
{
tree var = referenced_var (i);
/* If VAR is read-only, don't add a V_MAY_DEF, just a
VUSE operand. */
if (!TREE_READONLY (var))
add_stmt_operand (&var, stmt, opf_is_def, prev_vops);
else
add_stmt_operand (&var, stmt, opf_none, prev_vops);
});
}
}
/* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
function. */
static void
add_call_read_ops (tree stmt, voperands_t prev_vops)
{
/* Otherwise, if the function is not pure, it may reference memory. Add
a VUSE for .GLOBAL_VAR if it has been created. Otherwise, add a VUSE
for each call-clobbered variable. See add_referenced_var for the
heuristic used to decide whether to create .GLOBAL_VAR. */
if (global_var)
add_stmt_operand (&global_var, stmt, opf_none, prev_vops);
else
{
size_t i;
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i,
{
tree var = referenced_var (i);
add_stmt_operand (&var, stmt, opf_none, prev_vops);
});
}
}
/* Copies virtual operands from SRC to DST. */
void
copy_virtual_operands (tree dst, tree src)
{
vuse_optype vuses = STMT_VUSE_OPS (src);
v_may_def_optype v_may_defs = STMT_V_MAY_DEF_OPS (src);
v_must_def_optype v_must_defs = STMT_V_MUST_DEF_OPS (src);
vuse_optype *vuses_new = &stmt_ann (dst)->vuse_ops;
v_may_def_optype *v_may_defs_new = &stmt_ann (dst)->v_may_def_ops;
v_must_def_optype *v_must_defs_new = &stmt_ann (dst)->v_must_def_ops;
unsigned i;
if (vuses)
{
*vuses_new = allocate_vuse_optype (NUM_VUSES (vuses));
for (i = 0; i < NUM_VUSES (vuses); i++)
SET_VUSE_OP (*vuses_new, i, VUSE_OP (vuses, i));
}
if (v_may_defs)
{
*v_may_defs_new = allocate_v_may_def_optype (NUM_V_MAY_DEFS (v_may_defs));
for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
{
SET_V_MAY_DEF_OP (*v_may_defs_new, i, V_MAY_DEF_OP (v_may_defs, i));
SET_V_MAY_DEF_RESULT (*v_may_defs_new, i,
V_MAY_DEF_RESULT (v_may_defs, i));
}
}
if (v_must_defs)
{
*v_must_defs_new = allocate_v_must_def_optype (NUM_V_MUST_DEFS (v_must_defs));
for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
SET_V_MUST_DEF_OP (*v_must_defs_new, i, V_MUST_DEF_OP (v_must_defs, i));
}
}
#include "gt-tree-ssa-operands.h"
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