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Diffstat (limited to 'gcc/tree-stdarg.c')
-rw-r--r-- | gcc/tree-stdarg.c | 470 |
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 */ -}; |