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| Current File : //usr/src/contrib/gcc/tree-stdarg.c |
/* Pass computing data for optimizing stdarg functions.
Copyright (C) 2004, 2005 Free Software Foundation, Inc.
Contributed by Jakub Jelinek <jakub@redhat.com>
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 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, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "function.h"
#include "langhooks.h"
#include "diagnostic.h"
#include "target.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-stdarg.h"
/* A simple pass that attempts to optimize stdarg functions on architectures
that need to save register arguments to stack on entry to stdarg functions.
If the function doesn't use any va_start macros, no registers need to
be saved. If va_start macros are used, the va_list variables don't escape
the function, it is only necessary to save registers that will be used
in va_arg macros. E.g. if va_arg is only used with integral types
in the function, floating point registers don't need to be saved, etc. */
/* Return true if basic block VA_ARG_BB is dominated by VA_START_BB and
is executed at most as many times as VA_START_BB. */
static bool
reachable_at_most_once (basic_block va_arg_bb, basic_block va_start_bb)
{
edge *stack, e;
edge_iterator ei;
int sp;
sbitmap visited;
bool ret;
if (va_arg_bb == va_start_bb)
return true;
if (! dominated_by_p (CDI_DOMINATORS, va_arg_bb, va_start_bb))
return false;
stack = XNEWVEC (edge, n_basic_blocks + 1);
sp = 0;
visited = sbitmap_alloc (last_basic_block);
sbitmap_zero (visited);
ret = true;
FOR_EACH_EDGE (e, ei, va_arg_bb->preds)
stack[sp++] = e;
while (sp)
{
basic_block src;
--sp;
e = stack[sp];
src = e->src;
if (e->flags & EDGE_COMPLEX)
{
ret = false;
break;
}
if (src == va_start_bb)
continue;
/* va_arg_bb can be executed more times than va_start_bb. */
if (src == va_arg_bb)
{
ret = false;
break;
}
gcc_assert (src != ENTRY_BLOCK_PTR);
if (! TEST_BIT (visited, src->index))
{
SET_BIT (visited, src->index);
FOR_EACH_EDGE (e, ei, src->preds)
stack[sp++] = e;
}
}
free (stack);
sbitmap_free (visited);
return ret;
}
/* For statement COUNTER = RHS, if RHS is COUNTER + constant,
return constant, otherwise return (unsigned HOST_WIDE_INT) -1.
GPR_P is true if this is GPR counter. */
static unsigned HOST_WIDE_INT
va_list_counter_bump (struct stdarg_info *si, tree counter, tree rhs,
bool gpr_p)
{
tree stmt, lhs, orig_lhs;
unsigned HOST_WIDE_INT ret = 0, val, counter_val;
unsigned int max_size;
if (si->offsets == NULL)
{
unsigned int i;
si->offsets = XNEWVEC (int, num_ssa_names);
for (i = 0; i < num_ssa_names; ++i)
si->offsets[i] = -1;
}
counter_val = gpr_p ? cfun->va_list_gpr_size : cfun->va_list_fpr_size;
max_size = gpr_p ? VA_LIST_MAX_GPR_SIZE : VA_LIST_MAX_FPR_SIZE;
orig_lhs = lhs = rhs;
while (lhs)
{
if (si->offsets[SSA_NAME_VERSION (lhs)] != -1)
{
if (counter_val >= max_size)
{
ret = max_size;
break;
}
ret -= counter_val - si->offsets[SSA_NAME_VERSION (lhs)];
break;
}
stmt = SSA_NAME_DEF_STMT (lhs);
if (TREE_CODE (stmt) != MODIFY_EXPR
|| TREE_OPERAND (stmt, 0) != lhs)
return (unsigned HOST_WIDE_INT) -1;
rhs = TREE_OPERAND (stmt, 1);
if (TREE_CODE (rhs) == WITH_SIZE_EXPR)
rhs = TREE_OPERAND (rhs, 0);
if (TREE_CODE (rhs) == SSA_NAME)
{
lhs = rhs;
continue;
}
if ((TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
lhs = TREE_OPERAND (rhs, 0);
continue;
}
if (TREE_CODE (rhs) == PLUS_EXPR
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST
&& host_integerp (TREE_OPERAND (rhs, 1), 1))
{
ret += tree_low_cst (TREE_OPERAND (rhs, 1), 1);
lhs = TREE_OPERAND (rhs, 0);
continue;
}
if (TREE_CODE (counter) != TREE_CODE (rhs))
return (unsigned HOST_WIDE_INT) -1;
if (TREE_CODE (counter) == COMPONENT_REF)
{
if (get_base_address (counter) != get_base_address (rhs)
|| TREE_CODE (TREE_OPERAND (rhs, 1)) != FIELD_DECL
|| TREE_OPERAND (counter, 1) != TREE_OPERAND (rhs, 1))
return (unsigned HOST_WIDE_INT) -1;
}
else if (counter != rhs)
return (unsigned HOST_WIDE_INT) -1;
lhs = NULL;
}
lhs = orig_lhs;
val = ret + counter_val;
while (lhs)
{
if (si->offsets[SSA_NAME_VERSION (lhs)] != -1)
break;
if (val >= max_size)
si->offsets[SSA_NAME_VERSION (lhs)] = max_size;
else
si->offsets[SSA_NAME_VERSION (lhs)] = val;
stmt = SSA_NAME_DEF_STMT (lhs);
rhs = TREE_OPERAND (stmt, 1);
if (TREE_CODE (rhs) == WITH_SIZE_EXPR)
rhs = TREE_OPERAND (rhs, 0);
if (TREE_CODE (rhs) == SSA_NAME)
{
lhs = rhs;
continue;
}
if ((TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
{
lhs = TREE_OPERAND (rhs, 0);
continue;
}
if (TREE_CODE (rhs) == PLUS_EXPR
&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST
&& host_integerp (TREE_OPERAND (rhs, 1), 1))
{
val -= tree_low_cst (TREE_OPERAND (rhs, 1), 1);
lhs = TREE_OPERAND (rhs, 0);
continue;
}
lhs = NULL;
}
return ret;
}
/* Called by walk_tree to look for references to va_list variables. */
static tree
find_va_list_reference (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
void *data)
{
bitmap va_list_vars = (bitmap) data;
tree var = *tp;
if (TREE_CODE (var) == SSA_NAME)
var = SSA_NAME_VAR (var);
if (TREE_CODE (var) == VAR_DECL
&& bitmap_bit_p (va_list_vars, DECL_UID (var)))
return var;
return NULL_TREE;
}
/* Helper function of va_list_counter_struct_op. Compute
cfun->va_list_{g,f}pr_size. AP is a va_list GPR/FPR counter,
if WRITE_P is true, seen in AP = VAR, otherwise seen in VAR = AP
statement. GPR_P is true if AP is a GPR counter, false if it is
a FPR counter. */
static void
va_list_counter_op (struct stdarg_info *si, tree ap, tree var, bool gpr_p,
bool write_p)
{
unsigned HOST_WIDE_INT increment;
if (si->compute_sizes < 0)
{
si->compute_sizes = 0;
if (si->va_start_count == 1
&& reachable_at_most_once (si->bb, si->va_start_bb))
si->compute_sizes = 1;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"bb%d will %sbe executed at most once for each va_start "
"in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ",
si->va_start_bb->index);
}
if (write_p
&& si->compute_sizes
&& (increment = va_list_counter_bump (si, ap, var, gpr_p)) + 1 > 1)
{
if (gpr_p && cfun->va_list_gpr_size + increment < VA_LIST_MAX_GPR_SIZE)
{
cfun->va_list_gpr_size += increment;
return;
}
if (!gpr_p && cfun->va_list_fpr_size + increment < VA_LIST_MAX_FPR_SIZE)
{
cfun->va_list_fpr_size += increment;
return;
}
}
if (write_p || !si->compute_sizes)
{
if (gpr_p)
cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE;
else
cfun->va_list_fpr_size = VA_LIST_MAX_FPR_SIZE;
}
}
/* If AP is a va_list GPR/FPR counter, compute cfun->va_list_{g,f}pr_size.
If WRITE_P is true, AP has been seen in AP = VAR assignment, if WRITE_P
is false, AP has been seen in VAR = AP assignment.
Return true if the AP = VAR (resp. VAR = AP) statement is a recognized
va_arg operation that doesn't cause the va_list variable to escape
current function. */
static bool
va_list_counter_struct_op (struct stdarg_info *si, tree ap, tree var,
bool write_p)
{
tree base;
if (TREE_CODE (ap) != COMPONENT_REF
|| TREE_CODE (TREE_OPERAND (ap, 1)) != FIELD_DECL)
return false;
if (TREE_CODE (var) != SSA_NAME
|| bitmap_bit_p (si->va_list_vars, DECL_UID (SSA_NAME_VAR (var))))
return false;
base = get_base_address (ap);
if (TREE_CODE (base) != VAR_DECL
|| !bitmap_bit_p (si->va_list_vars, DECL_UID (base)))
return false;
if (TREE_OPERAND (ap, 1) == va_list_gpr_counter_field)
va_list_counter_op (si, ap, var, true, write_p);
else if (TREE_OPERAND (ap, 1) == va_list_fpr_counter_field)
va_list_counter_op (si, ap, var, false, write_p);
return true;
}
/* Check for TEM = AP. Return true if found and the caller shouldn't
search for va_list references in the statement. */
static bool
va_list_ptr_read (struct stdarg_info *si, tree ap, tree tem)
{
if (TREE_CODE (ap) != VAR_DECL
|| !bitmap_bit_p (si->va_list_vars, DECL_UID (ap)))
return false;
if (TREE_CODE (tem) != SSA_NAME
|| bitmap_bit_p (si->va_list_vars,
DECL_UID (SSA_NAME_VAR (tem)))
|| is_global_var (SSA_NAME_VAR (tem)))
return false;
if (si->compute_sizes < 0)
{
si->compute_sizes = 0;
if (si->va_start_count == 1
&& reachable_at_most_once (si->bb, si->va_start_bb))
si->compute_sizes = 1;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"bb%d will %sbe executed at most once for each va_start "
"in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ",
si->va_start_bb->index);
}
/* For void * or char * va_list types, there is just one counter.
If va_arg is used in a loop, we don't know how many registers need
saving. */
if (! si->compute_sizes)
return false;
if (va_list_counter_bump (si, ap, tem, true) == (unsigned HOST_WIDE_INT) -1)
return false;
/* Note the temporary, as we need to track whether it doesn't escape
the current function. */
bitmap_set_bit (si->va_list_escape_vars,
DECL_UID (SSA_NAME_VAR (tem)));
return true;
}
/* Check for:
tem1 = AP;
TEM2 = tem1 + CST;
AP = TEM2;
sequence and update cfun->va_list_gpr_size. Return true if found. */
static bool
va_list_ptr_write (struct stdarg_info *si, tree ap, tree tem2)
{
unsigned HOST_WIDE_INT increment;
if (TREE_CODE (ap) != VAR_DECL
|| !bitmap_bit_p (si->va_list_vars, DECL_UID (ap)))
return false;
if (TREE_CODE (tem2) != SSA_NAME
|| bitmap_bit_p (si->va_list_vars, DECL_UID (SSA_NAME_VAR (tem2))))
return false;
if (si->compute_sizes <= 0)
return false;
increment = va_list_counter_bump (si, ap, tem2, true);
if (increment + 1 <= 1)
return false;
if (cfun->va_list_gpr_size + increment < VA_LIST_MAX_GPR_SIZE)
cfun->va_list_gpr_size += increment;
else
cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE;
return true;
}
/* If RHS is X, (some type *) X or X + CST for X a temporary variable
containing value of some va_list variable plus optionally some constant,
either set si->va_list_escapes or add LHS to si->va_list_escape_vars,
depending whether LHS is a function local temporary. */
static void
check_va_list_escapes (struct stdarg_info *si, tree lhs, tree rhs)
{
if (! POINTER_TYPE_P (TREE_TYPE (rhs)))
return;
if ((TREE_CODE (rhs) == PLUS_EXPR
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
|| TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
rhs = TREE_OPERAND (rhs, 0);
if (TREE_CODE (rhs) != SSA_NAME
|| ! bitmap_bit_p (si->va_list_escape_vars,
DECL_UID (SSA_NAME_VAR (rhs))))
return;
if (TREE_CODE (lhs) != SSA_NAME || is_global_var (SSA_NAME_VAR (lhs)))
{
si->va_list_escapes = true;
return;
}
if (si->compute_sizes < 0)
{
si->compute_sizes = 0;
if (si->va_start_count == 1
&& reachable_at_most_once (si->bb, si->va_start_bb))
si->compute_sizes = 1;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"bb%d will %sbe executed at most once for each va_start "
"in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ",
si->va_start_bb->index);
}
/* For void * or char * va_list types, there is just one counter.
If va_arg is used in a loop, we don't know how many registers need
saving. */
if (! si->compute_sizes)
{
si->va_list_escapes = true;
return;
}
if (va_list_counter_bump (si, si->va_start_ap, lhs, true)
== (unsigned HOST_WIDE_INT) -1)
{
si->va_list_escapes = true;
return;
}
bitmap_set_bit (si->va_list_escape_vars,
DECL_UID (SSA_NAME_VAR (lhs)));
}
/* Check all uses of temporaries from si->va_list_escape_vars bitmap.
Return true if va_list might be escaping. */
static bool
check_all_va_list_escapes (struct stdarg_info *si)
{
basic_block bb;
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
{
tree stmt = bsi_stmt (i), use;
ssa_op_iter iter;
FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_ALL_USES)
{
if (! bitmap_bit_p (si->va_list_escape_vars,
DECL_UID (SSA_NAME_VAR (use))))
continue;
if (TREE_CODE (stmt) == MODIFY_EXPR)
{
tree lhs = TREE_OPERAND (stmt, 0);
tree rhs = TREE_OPERAND (stmt, 1);
if (TREE_CODE (rhs) == WITH_SIZE_EXPR)
rhs = TREE_OPERAND (rhs, 0);
/* x = *ap_temp; */
if (TREE_CODE (rhs) == INDIRECT_REF
&& TREE_OPERAND (rhs, 0) == use
&& TYPE_SIZE_UNIT (TREE_TYPE (rhs))
&& host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (rhs)), 1)
&& si->offsets[SSA_NAME_VERSION (use)] != -1)
{
unsigned HOST_WIDE_INT gpr_size;
tree access_size = TYPE_SIZE_UNIT (TREE_TYPE (rhs));
gpr_size = si->offsets[SSA_NAME_VERSION (use)]
+ tree_low_cst (access_size, 1);
if (gpr_size >= VA_LIST_MAX_GPR_SIZE)
cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE;
else if (gpr_size > cfun->va_list_gpr_size)
cfun->va_list_gpr_size = gpr_size;
continue;
}
/* va_arg sequences may contain
other_ap_temp = ap_temp;
other_ap_temp = ap_temp + constant;
other_ap_temp = (some_type *) ap_temp;
ap = ap_temp;
statements. */
if ((TREE_CODE (rhs) == PLUS_EXPR
&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
|| TREE_CODE (rhs) == NOP_EXPR
|| TREE_CODE (rhs) == CONVERT_EXPR)
rhs = TREE_OPERAND (rhs, 0);
if (rhs == use)
{
if (TREE_CODE (lhs) == SSA_NAME
&& bitmap_bit_p (si->va_list_escape_vars,
DECL_UID (SSA_NAME_VAR (lhs))))
continue;
if (TREE_CODE (lhs) == VAR_DECL
&& bitmap_bit_p (si->va_list_vars,
DECL_UID (lhs)))
continue;
}
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fputs ("va_list escapes in ", dump_file);
print_generic_expr (dump_file, stmt, dump_flags);
fputc ('\n', dump_file);
}
return true;
}
}
}
return false;
}
/* Return true if this optimization pass should be done.
It makes only sense for stdarg functions. */
static bool
gate_optimize_stdarg (void)
{
/* This optimization is only for stdarg functions. */
return current_function_stdarg != 0;
}
/* Entry point to the stdarg optimization pass. */
static unsigned int
execute_optimize_stdarg (void)
{
basic_block bb;
bool va_list_escapes = false;
bool va_list_simple_ptr;
struct stdarg_info si;
const char *funcname = NULL;
cfun->va_list_gpr_size = 0;
cfun->va_list_fpr_size = 0;
memset (&si, 0, sizeof (si));
si.va_list_vars = BITMAP_ALLOC (NULL);
si.va_list_escape_vars = BITMAP_ALLOC (NULL);
if (dump_file)
funcname = lang_hooks.decl_printable_name (current_function_decl, 2);
va_list_simple_ptr = POINTER_TYPE_P (va_list_type_node)
&& (TREE_TYPE (va_list_type_node) == void_type_node
|| TREE_TYPE (va_list_type_node) == char_type_node);
gcc_assert (is_gimple_reg_type (va_list_type_node) == va_list_simple_ptr);
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
{
tree stmt = bsi_stmt (i);
tree call = get_call_expr_in (stmt), callee;
tree ap;
if (!call)
continue;
callee = get_callee_fndecl (call);
if (!callee
|| DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL)
continue;
switch (DECL_FUNCTION_CODE (callee))
{
case BUILT_IN_VA_START:
break;
/* If old style builtins are used, don't optimize anything. */
case BUILT_IN_SAVEREGS:
case BUILT_IN_STDARG_START:
case BUILT_IN_ARGS_INFO:
case BUILT_IN_NEXT_ARG:
va_list_escapes = true;
continue;
default:
continue;
}
si.va_start_count++;
ap = TREE_VALUE (TREE_OPERAND (call, 1));
if (TREE_CODE (ap) != ADDR_EXPR)
{
va_list_escapes = true;
break;
}
ap = TREE_OPERAND (ap, 0);
if (TREE_CODE (ap) == ARRAY_REF)
{
if (! integer_zerop (TREE_OPERAND (ap, 1)))
{
va_list_escapes = true;
break;
}
ap = TREE_OPERAND (ap, 0);
}
if (TYPE_MAIN_VARIANT (TREE_TYPE (ap))
!= TYPE_MAIN_VARIANT (va_list_type_node)
|| TREE_CODE (ap) != VAR_DECL)
{
va_list_escapes = true;
break;
}
if (is_global_var (ap))
{
va_list_escapes = true;
break;
}
bitmap_set_bit (si.va_list_vars, DECL_UID (ap));
/* VA_START_BB and VA_START_AP will be only used if there is just
one va_start in the function. */
si.va_start_bb = bb;
si.va_start_ap = ap;
}
if (va_list_escapes)
break;
}
/* If there were no va_start uses in the function, there is no need to
save anything. */
if (si.va_start_count == 0)
goto finish;
/* If some va_list arguments weren't local, we can't optimize. */
if (va_list_escapes)
goto finish;
/* For void * or char * va_list, something useful can be done only
if there is just one va_start. */
if (va_list_simple_ptr && si.va_start_count > 1)
{
va_list_escapes = true;
goto finish;
}
/* For struct * va_list, if the backend didn't tell us what the counter fields
are, there is nothing more we can do. */
if (!va_list_simple_ptr
&& va_list_gpr_counter_field == NULL_TREE
&& va_list_fpr_counter_field == NULL_TREE)
{
va_list_escapes = true;
goto finish;
}
/* For void * or char * va_list there is just one counter
(va_list itself). Use VA_LIST_GPR_SIZE for it. */
if (va_list_simple_ptr)
cfun->va_list_fpr_size = VA_LIST_MAX_FPR_SIZE;
calculate_dominance_info (CDI_DOMINATORS);
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
si.compute_sizes = -1;
si.bb = bb;
/* For va_list_simple_ptr, we have to check PHI nodes too. We treat
them as assignments for the purpose of escape analysis. This is
not needed for non-simple va_list because virtual phis don't perform
any real data movement. */
if (va_list_simple_ptr)
{
tree phi, lhs, rhs;
use_operand_p uop;
ssa_op_iter soi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
{
lhs = PHI_RESULT (phi);
if (!is_gimple_reg (lhs))
continue;
FOR_EACH_PHI_ARG (uop, phi, soi, SSA_OP_USE)
{
rhs = USE_FROM_PTR (uop);
if (va_list_ptr_read (&si, rhs, lhs))
continue;
else if (va_list_ptr_write (&si, lhs, rhs))
continue;
else
check_va_list_escapes (&si, lhs, rhs);
if (si.va_list_escapes
|| walk_tree (&phi, find_va_list_reference,
si.va_list_vars, NULL))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fputs ("va_list escapes in ", dump_file);
print_generic_expr (dump_file, phi, dump_flags);
fputc ('\n', dump_file);
}
va_list_escapes = true;
}
}
}
}
for (i = bsi_start (bb);
!bsi_end_p (i) && !va_list_escapes;
bsi_next (&i))
{
tree stmt = bsi_stmt (i);
tree call;
/* Don't look at __builtin_va_{start,end}, they are ok. */
call = get_call_expr_in (stmt);
if (call)
{
tree callee = get_callee_fndecl (call);
if (callee
&& DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL
&& (DECL_FUNCTION_CODE (callee) == BUILT_IN_VA_START
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_VA_END))
continue;
}
if (TREE_CODE (stmt) == MODIFY_EXPR)
{
tree lhs = TREE_OPERAND (stmt, 0);
tree rhs = TREE_OPERAND (stmt, 1);
if (TREE_CODE (rhs) == WITH_SIZE_EXPR)
rhs = TREE_OPERAND (rhs, 0);
if (va_list_simple_ptr)
{
/* Check for tem = ap. */
if (va_list_ptr_read (&si, rhs, lhs))
continue;
/* Check for the last insn in:
tem1 = ap;
tem2 = tem1 + CST;
ap = tem2;
sequence. */
else if (va_list_ptr_write (&si, lhs, rhs))
continue;
else
check_va_list_escapes (&si, lhs, rhs);
}
else
{
/* Check for ap[0].field = temp. */
if (va_list_counter_struct_op (&si, lhs, rhs, true))
continue;
/* Check for temp = ap[0].field. */
else if (va_list_counter_struct_op (&si, rhs, lhs, false))
continue;
/* Do any architecture specific checking. */
else if (targetm.stdarg_optimize_hook
&& targetm.stdarg_optimize_hook (&si, lhs, rhs))
continue;
}
}
/* All other uses of va_list are either va_copy (that is not handled
in this optimization), taking address of va_list variable or
passing va_list to other functions (in that case va_list might
escape the function and therefore va_start needs to set it up
fully), or some unexpected use of va_list. None of these should
happen in a gimplified VA_ARG_EXPR. */
if (si.va_list_escapes
|| walk_tree (&stmt, find_va_list_reference,
si.va_list_vars, NULL))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fputs ("va_list escapes in ", dump_file);
print_generic_expr (dump_file, stmt, dump_flags);
fputc ('\n', dump_file);
}
va_list_escapes = true;
}
}
if (va_list_escapes)
break;
}
if (! va_list_escapes
&& va_list_simple_ptr
&& ! bitmap_empty_p (si.va_list_escape_vars)
&& check_all_va_list_escapes (&si))
va_list_escapes = true;
finish:
if (va_list_escapes)
{
cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE;
cfun->va_list_fpr_size = VA_LIST_MAX_FPR_SIZE;
}
BITMAP_FREE (si.va_list_vars);
BITMAP_FREE (si.va_list_escape_vars);
free (si.offsets);
if (dump_file)
{
fprintf (dump_file, "%s: va_list escapes %d, needs to save ",
funcname, (int) va_list_escapes);
if (cfun->va_list_gpr_size >= VA_LIST_MAX_GPR_SIZE)
fputs ("all", dump_file);
else
fprintf (dump_file, "%d", cfun->va_list_gpr_size);
fputs (" GPR units and ", dump_file);
if (cfun->va_list_fpr_size >= VA_LIST_MAX_FPR_SIZE)
fputs ("all", dump_file);
else
fprintf (dump_file, "%d", cfun->va_list_fpr_size);
fputs (" FPR units.\n", dump_file);
}
return 0;
}
struct tree_opt_pass pass_stdarg =
{
"stdarg", /* name */
gate_optimize_stdarg, /* gate */
execute_optimize_stdarg, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* tv_id */
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func, /* todo_flags_finish */
0 /* letter */
};