summaryrefslogtreecommitdiff
path: root/gcc/tree-stdarg.c
diff options
context:
space:
mode:
Diffstat (limited to 'gcc/tree-stdarg.c')
-rw-r--r--gcc/tree-stdarg.c470
1 files changed, 0 insertions, 470 deletions
diff --git a/gcc/tree-stdarg.c b/gcc/tree-stdarg.c
deleted file mode 100644
index 926563793ca..00000000000
--- a/gcc/tree-stdarg.c
+++ /dev/null
@@ -1,470 +0,0 @@
-/* Pass computing data for optimizing stdarg functions.
- Copyright (C) 2004 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, 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 "function.h"
-#include "langhooks.h"
-#include "diagnostic.h"
-#include "tree-flow.h"
-#include "tree-pass.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. */
-
-struct stdarg_info
-{
- bitmap va_list_vars;
- basic_block va_start_bb, bb;
- int compute_sizes, va_start_count;
-};
-
-/* 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 = xmalloc ((n_basic_blocks + 1) * sizeof (edge));
- 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 0. */
-
-static unsigned HOST_WIDE_INT
-va_list_counter_bump (tree counter, tree rhs)
-{
- tree plus_stmt = SSA_NAME_DEF_STMT (rhs);
- tree rhs1, addend, load_stmt, counter1;
-
- if (TREE_CODE (plus_stmt) != MODIFY_EXPR
- || TREE_OPERAND (plus_stmt, 0) != rhs)
- return 0;
-
- rhs1 = TREE_OPERAND (plus_stmt, 1);
-
- if (TREE_CODE (rhs1) != PLUS_EXPR
- || TREE_CODE (TREE_OPERAND (rhs1, 0)) != SSA_NAME
- || TREE_CODE (TREE_OPERAND (rhs1, 1)) != INTEGER_CST
- || !host_integerp (TREE_OPERAND (rhs1, 1), 1))
- return 0;
-
- addend = TREE_OPERAND (rhs1, 0);
- load_stmt = SSA_NAME_DEF_STMT (addend);
-
- if (TREE_CODE (load_stmt) != MODIFY_EXPR
- || TREE_OPERAND (load_stmt, 0) != addend)
- return 0;
-
- counter1 = TREE_OPERAND (load_stmt, 1);
- if (TREE_CODE (counter) != TREE_CODE (counter1))
- return 0;
-
- if (TREE_CODE (counter) == COMPONENT_REF)
- {
- if (get_base_address (counter) != get_base_address (counter1)
- || TREE_CODE (TREE_OPERAND (counter1, 1)) != FIELD_DECL
- || TREE_OPERAND (counter, 1) != TREE_OPERAND (counter1, 1))
- return 0;
- }
- else
- return 0;
-
- return tree_low_cst (TREE_OPERAND (rhs1, 1), 1);
-}
-
-
-/* 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, var_ann (var)->uid))
- 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 (ap, var)) != 0)
- {
- 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, var_ann (SSA_NAME_VAR (var))->uid))
- return false;
-
- base = get_base_address (ap);
- if (TREE_CODE (base) != VAR_DECL
- || !bitmap_bit_p (si->va_list_vars, var_ann (base)->uid))
- 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;
-}
-
-
-/* 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 void
-execute_optimize_stdarg (void)
-{
- basic_block bb;
- bool va_list_escapes = false;
- 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_XMALLOC ();
-
- if (dump_file)
- funcname = lang_hooks.decl_printable_name (current_function_decl, 2);
-
- 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
- || DECL_FUNCTION_CODE (callee) != BUILT_IN_VA_START)
- continue;
-
- si.va_start_count++;
- ap = TREE_VALUE (TREE_OPERAND (call, 1));
- if (TREE_CODE (ap) != ADDR_EXPR
- || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (ap, 0)))
- != TYPE_MAIN_VARIANT (va_list_type_node)
- || TREE_CODE (TREE_OPERAND (ap, 0)) != VAR_DECL)
- {
- va_list_escapes = true;
- break;
- }
-
- ap = TREE_OPERAND (ap, 0);
- if (is_global_var (ap))
- {
- va_list_escapes = true;
- break;
- }
-
- bitmap_set_bit (si.va_list_vars, var_ann (ap)->uid);
-
- /* VA_START_BB will be only used if there is just one
- va_start in the function. */
- si.va_start_bb = bb;
- }
-
- 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;
-
- /* If the backend didn't tell us what the counter fields are, there is
- nothing more we can do. */
- if (va_list_gpr_counter_field == NULL_TREE
- && va_list_fpr_counter_field == NULL_TREE)
- {
- va_list_escapes = true;
- goto finish;
- }
-
- FOR_EACH_BB (bb)
- {
- block_stmt_iterator i;
-
- si.compute_sizes = -1;
- si.bb = bb;
- 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);
-
- /* 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;
- }
-
- /* 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 (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;
- }
-
-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_XFREE (si.va_list_vars);
- 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);
- }
-}
-
-
-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 */
-};