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926 lines
24 KiB
C
926 lines
24 KiB
C
/* Pass computing data for optimizing stdarg functions.
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Copyright (C) 2004, 2005 Free Software Foundation, Inc.
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Contributed by Jakub Jelinek <jakub@redhat.com>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "function.h"
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#include "langhooks.h"
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#include "diagnostic.h"
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#include "target.h"
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#include "tree-flow.h"
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#include "tree-pass.h"
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#include "tree-stdarg.h"
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/* A simple pass that attempts to optimize stdarg functions on architectures
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that need to save register arguments to stack on entry to stdarg functions.
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If the function doesn't use any va_start macros, no registers need to
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be saved. If va_start macros are used, the va_list variables don't escape
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the function, it is only necessary to save registers that will be used
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in va_arg macros. E.g. if va_arg is only used with integral types
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in the function, floating point registers don't need to be saved, etc. */
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/* Return true if basic block VA_ARG_BB is dominated by VA_START_BB and
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is executed at most as many times as VA_START_BB. */
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static bool
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reachable_at_most_once (basic_block va_arg_bb, basic_block va_start_bb)
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{
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edge *stack, e;
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edge_iterator ei;
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int sp;
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sbitmap visited;
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bool ret;
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if (va_arg_bb == va_start_bb)
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return true;
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if (! dominated_by_p (CDI_DOMINATORS, va_arg_bb, va_start_bb))
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return false;
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stack = XNEWVEC (edge, n_basic_blocks + 1);
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sp = 0;
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visited = sbitmap_alloc (last_basic_block);
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sbitmap_zero (visited);
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ret = true;
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FOR_EACH_EDGE (e, ei, va_arg_bb->preds)
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stack[sp++] = e;
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while (sp)
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{
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basic_block src;
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--sp;
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e = stack[sp];
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src = e->src;
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if (e->flags & EDGE_COMPLEX)
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{
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ret = false;
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break;
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}
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if (src == va_start_bb)
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continue;
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/* va_arg_bb can be executed more times than va_start_bb. */
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if (src == va_arg_bb)
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{
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ret = false;
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break;
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}
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gcc_assert (src != ENTRY_BLOCK_PTR);
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if (! TEST_BIT (visited, src->index))
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{
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SET_BIT (visited, src->index);
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FOR_EACH_EDGE (e, ei, src->preds)
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stack[sp++] = e;
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}
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}
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free (stack);
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sbitmap_free (visited);
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return ret;
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}
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/* For statement COUNTER = RHS, if RHS is COUNTER + constant,
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return constant, otherwise return (unsigned HOST_WIDE_INT) -1.
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GPR_P is true if this is GPR counter. */
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static unsigned HOST_WIDE_INT
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va_list_counter_bump (struct stdarg_info *si, tree counter, tree rhs,
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bool gpr_p)
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{
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tree stmt, lhs, orig_lhs;
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unsigned HOST_WIDE_INT ret = 0, val, counter_val;
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unsigned int max_size;
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if (si->offsets == NULL)
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{
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unsigned int i;
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si->offsets = XNEWVEC (int, num_ssa_names);
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for (i = 0; i < num_ssa_names; ++i)
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si->offsets[i] = -1;
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}
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counter_val = gpr_p ? cfun->va_list_gpr_size : cfun->va_list_fpr_size;
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max_size = gpr_p ? VA_LIST_MAX_GPR_SIZE : VA_LIST_MAX_FPR_SIZE;
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orig_lhs = lhs = rhs;
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while (lhs)
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{
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if (si->offsets[SSA_NAME_VERSION (lhs)] != -1)
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{
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if (counter_val >= max_size)
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{
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ret = max_size;
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break;
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}
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ret -= counter_val - si->offsets[SSA_NAME_VERSION (lhs)];
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break;
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}
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stmt = SSA_NAME_DEF_STMT (lhs);
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if (TREE_CODE (stmt) != MODIFY_EXPR
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|| TREE_OPERAND (stmt, 0) != lhs)
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return (unsigned HOST_WIDE_INT) -1;
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rhs = TREE_OPERAND (stmt, 1);
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if (TREE_CODE (rhs) == WITH_SIZE_EXPR)
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rhs = TREE_OPERAND (rhs, 0);
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if (TREE_CODE (rhs) == SSA_NAME)
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{
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lhs = rhs;
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continue;
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}
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if ((TREE_CODE (rhs) == NOP_EXPR
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|| TREE_CODE (rhs) == CONVERT_EXPR)
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&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
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{
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lhs = TREE_OPERAND (rhs, 0);
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continue;
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}
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if (TREE_CODE (rhs) == PLUS_EXPR
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&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
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&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST
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&& host_integerp (TREE_OPERAND (rhs, 1), 1))
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{
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ret += tree_low_cst (TREE_OPERAND (rhs, 1), 1);
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lhs = TREE_OPERAND (rhs, 0);
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continue;
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}
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if (TREE_CODE (counter) != TREE_CODE (rhs))
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return (unsigned HOST_WIDE_INT) -1;
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if (TREE_CODE (counter) == COMPONENT_REF)
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{
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if (get_base_address (counter) != get_base_address (rhs)
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|| TREE_CODE (TREE_OPERAND (rhs, 1)) != FIELD_DECL
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|| TREE_OPERAND (counter, 1) != TREE_OPERAND (rhs, 1))
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return (unsigned HOST_WIDE_INT) -1;
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}
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else if (counter != rhs)
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return (unsigned HOST_WIDE_INT) -1;
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lhs = NULL;
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}
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lhs = orig_lhs;
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val = ret + counter_val;
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while (lhs)
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{
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if (si->offsets[SSA_NAME_VERSION (lhs)] != -1)
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break;
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if (val >= max_size)
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si->offsets[SSA_NAME_VERSION (lhs)] = max_size;
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else
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si->offsets[SSA_NAME_VERSION (lhs)] = val;
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stmt = SSA_NAME_DEF_STMT (lhs);
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rhs = TREE_OPERAND (stmt, 1);
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if (TREE_CODE (rhs) == WITH_SIZE_EXPR)
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rhs = TREE_OPERAND (rhs, 0);
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if (TREE_CODE (rhs) == SSA_NAME)
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{
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lhs = rhs;
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continue;
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}
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if ((TREE_CODE (rhs) == NOP_EXPR
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|| TREE_CODE (rhs) == CONVERT_EXPR)
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&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
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{
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lhs = TREE_OPERAND (rhs, 0);
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continue;
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}
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if (TREE_CODE (rhs) == PLUS_EXPR
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&& TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
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&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST
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&& host_integerp (TREE_OPERAND (rhs, 1), 1))
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{
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val -= tree_low_cst (TREE_OPERAND (rhs, 1), 1);
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lhs = TREE_OPERAND (rhs, 0);
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continue;
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}
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lhs = NULL;
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}
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return ret;
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}
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/* Called by walk_tree to look for references to va_list variables. */
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static tree
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find_va_list_reference (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
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void *data)
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{
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bitmap va_list_vars = (bitmap) data;
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tree var = *tp;
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if (TREE_CODE (var) == SSA_NAME)
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var = SSA_NAME_VAR (var);
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if (TREE_CODE (var) == VAR_DECL
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&& bitmap_bit_p (va_list_vars, DECL_UID (var)))
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return var;
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return NULL_TREE;
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}
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/* Helper function of va_list_counter_struct_op. Compute
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cfun->va_list_{g,f}pr_size. AP is a va_list GPR/FPR counter,
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if WRITE_P is true, seen in AP = VAR, otherwise seen in VAR = AP
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statement. GPR_P is true if AP is a GPR counter, false if it is
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a FPR counter. */
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static void
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va_list_counter_op (struct stdarg_info *si, tree ap, tree var, bool gpr_p,
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bool write_p)
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{
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unsigned HOST_WIDE_INT increment;
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if (si->compute_sizes < 0)
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{
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si->compute_sizes = 0;
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if (si->va_start_count == 1
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&& reachable_at_most_once (si->bb, si->va_start_bb))
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si->compute_sizes = 1;
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if (dump_file && (dump_flags & TDF_DETAILS))
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fprintf (dump_file,
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"bb%d will %sbe executed at most once for each va_start "
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"in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ",
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si->va_start_bb->index);
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}
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if (write_p
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&& si->compute_sizes
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&& (increment = va_list_counter_bump (si, ap, var, gpr_p)) + 1 > 1)
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{
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if (gpr_p && cfun->va_list_gpr_size + increment < VA_LIST_MAX_GPR_SIZE)
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{
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cfun->va_list_gpr_size += increment;
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return;
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}
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if (!gpr_p && cfun->va_list_fpr_size + increment < VA_LIST_MAX_FPR_SIZE)
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{
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cfun->va_list_fpr_size += increment;
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return;
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}
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}
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if (write_p || !si->compute_sizes)
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{
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if (gpr_p)
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cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE;
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else
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cfun->va_list_fpr_size = VA_LIST_MAX_FPR_SIZE;
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}
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}
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/* If AP is a va_list GPR/FPR counter, compute cfun->va_list_{g,f}pr_size.
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If WRITE_P is true, AP has been seen in AP = VAR assignment, if WRITE_P
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is false, AP has been seen in VAR = AP assignment.
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Return true if the AP = VAR (resp. VAR = AP) statement is a recognized
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va_arg operation that doesn't cause the va_list variable to escape
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current function. */
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static bool
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va_list_counter_struct_op (struct stdarg_info *si, tree ap, tree var,
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bool write_p)
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{
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tree base;
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if (TREE_CODE (ap) != COMPONENT_REF
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|| TREE_CODE (TREE_OPERAND (ap, 1)) != FIELD_DECL)
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return false;
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if (TREE_CODE (var) != SSA_NAME
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|| bitmap_bit_p (si->va_list_vars, DECL_UID (SSA_NAME_VAR (var))))
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return false;
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base = get_base_address (ap);
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if (TREE_CODE (base) != VAR_DECL
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|| !bitmap_bit_p (si->va_list_vars, DECL_UID (base)))
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return false;
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if (TREE_OPERAND (ap, 1) == va_list_gpr_counter_field)
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va_list_counter_op (si, ap, var, true, write_p);
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else if (TREE_OPERAND (ap, 1) == va_list_fpr_counter_field)
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va_list_counter_op (si, ap, var, false, write_p);
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return true;
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}
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/* Check for TEM = AP. Return true if found and the caller shouldn't
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search for va_list references in the statement. */
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static bool
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va_list_ptr_read (struct stdarg_info *si, tree ap, tree tem)
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{
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if (TREE_CODE (ap) != VAR_DECL
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|| !bitmap_bit_p (si->va_list_vars, DECL_UID (ap)))
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return false;
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if (TREE_CODE (tem) != SSA_NAME
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|| bitmap_bit_p (si->va_list_vars,
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DECL_UID (SSA_NAME_VAR (tem)))
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|| is_global_var (SSA_NAME_VAR (tem)))
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return false;
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if (si->compute_sizes < 0)
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{
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si->compute_sizes = 0;
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if (si->va_start_count == 1
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&& reachable_at_most_once (si->bb, si->va_start_bb))
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si->compute_sizes = 1;
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if (dump_file && (dump_flags & TDF_DETAILS))
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fprintf (dump_file,
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"bb%d will %sbe executed at most once for each va_start "
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"in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ",
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si->va_start_bb->index);
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}
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/* For void * or char * va_list types, there is just one counter.
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If va_arg is used in a loop, we don't know how many registers need
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saving. */
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if (! si->compute_sizes)
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return false;
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if (va_list_counter_bump (si, ap, tem, true) == (unsigned HOST_WIDE_INT) -1)
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return false;
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/* Note the temporary, as we need to track whether it doesn't escape
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the current function. */
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bitmap_set_bit (si->va_list_escape_vars,
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DECL_UID (SSA_NAME_VAR (tem)));
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return true;
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}
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/* Check for:
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tem1 = AP;
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TEM2 = tem1 + CST;
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AP = TEM2;
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sequence and update cfun->va_list_gpr_size. Return true if found. */
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static bool
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va_list_ptr_write (struct stdarg_info *si, tree ap, tree tem2)
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{
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unsigned HOST_WIDE_INT increment;
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if (TREE_CODE (ap) != VAR_DECL
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|| !bitmap_bit_p (si->va_list_vars, DECL_UID (ap)))
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return false;
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if (TREE_CODE (tem2) != SSA_NAME
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|| bitmap_bit_p (si->va_list_vars, DECL_UID (SSA_NAME_VAR (tem2))))
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return false;
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if (si->compute_sizes <= 0)
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return false;
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increment = va_list_counter_bump (si, ap, tem2, true);
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if (increment + 1 <= 1)
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return false;
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if (cfun->va_list_gpr_size + increment < VA_LIST_MAX_GPR_SIZE)
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cfun->va_list_gpr_size += increment;
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else
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cfun->va_list_gpr_size = VA_LIST_MAX_GPR_SIZE;
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return true;
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}
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/* If RHS is X, (some type *) X or X + CST for X a temporary variable
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containing value of some va_list variable plus optionally some constant,
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either set si->va_list_escapes or add LHS to si->va_list_escape_vars,
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depending whether LHS is a function local temporary. */
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static void
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check_va_list_escapes (struct stdarg_info *si, tree lhs, tree rhs)
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{
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if (! POINTER_TYPE_P (TREE_TYPE (rhs)))
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return;
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if ((TREE_CODE (rhs) == PLUS_EXPR
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&& TREE_CODE (TREE_OPERAND (rhs, 1)) == INTEGER_CST)
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|| TREE_CODE (rhs) == NOP_EXPR
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|| TREE_CODE (rhs) == CONVERT_EXPR)
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rhs = TREE_OPERAND (rhs, 0);
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if (TREE_CODE (rhs) != SSA_NAME
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|| ! bitmap_bit_p (si->va_list_escape_vars,
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DECL_UID (SSA_NAME_VAR (rhs))))
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return;
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if (TREE_CODE (lhs) != SSA_NAME || is_global_var (SSA_NAME_VAR (lhs)))
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{
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si->va_list_escapes = true;
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return;
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}
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if (si->compute_sizes < 0)
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{
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si->compute_sizes = 0;
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if (si->va_start_count == 1
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&& reachable_at_most_once (si->bb, si->va_start_bb))
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si->compute_sizes = 1;
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if (dump_file && (dump_flags & TDF_DETAILS))
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fprintf (dump_file,
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"bb%d will %sbe executed at most once for each va_start "
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"in bb%d\n", si->bb->index, si->compute_sizes ? "" : "not ",
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si->va_start_bb->index);
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}
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/* For void * or char * va_list types, there is just one counter.
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|
If va_arg is used in a loop, we don't know how many registers need
|
|
saving. */
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if (! si->compute_sizes)
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{
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si->va_list_escapes = true;
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return;
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}
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if (va_list_counter_bump (si, si->va_start_ap, lhs, true)
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== (unsigned HOST_WIDE_INT) -1)
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{
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si->va_list_escapes = true;
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return;
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}
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bitmap_set_bit (si->va_list_escape_vars,
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DECL_UID (SSA_NAME_VAR (lhs)));
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}
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|
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/* 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 */
|
|
};
|