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Diffstat (limited to 'contrib/gcc/tree-dfa.c')
| -rw-r--r-- | contrib/gcc/tree-dfa.c | 1032 |
1 files changed, 1032 insertions, 0 deletions
diff --git a/contrib/gcc/tree-dfa.c b/contrib/gcc/tree-dfa.c new file mode 100644 index 0000000..5ade645 --- /dev/null +++ b/contrib/gcc/tree-dfa.c @@ -0,0 +1,1032 @@ +/* Data flow functions for trees. + Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. + Contributed by Diego Novillo <dnovillo@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 "hashtab.h" +#include "pointer-set.h" +#include "tree.h" +#include "rtl.h" +#include "tm_p.h" +#include "hard-reg-set.h" +#include "basic-block.h" +#include "output.h" +#include "timevar.h" +#include "expr.h" +#include "ggc.h" +#include "langhooks.h" +#include "flags.h" +#include "function.h" +#include "diagnostic.h" +#include "tree-dump.h" +#include "tree-gimple.h" +#include "tree-flow.h" +#include "tree-inline.h" +#include "tree-pass.h" +#include "convert.h" +#include "params.h" +#include "cgraph.h" + +/* Build and maintain data flow information for trees. */ + +/* Counters used to display DFA and SSA statistics. */ +struct dfa_stats_d +{ + long num_stmt_anns; + long num_var_anns; + long num_defs; + long num_uses; + long num_phis; + long num_phi_args; + int max_num_phi_args; + long num_v_may_defs; + long num_vuses; + long num_v_must_defs; +}; + + +/* Local functions. */ +static void collect_dfa_stats (struct dfa_stats_d *); +static tree collect_dfa_stats_r (tree *, int *, void *); +static tree find_vars_r (tree *, int *, void *); + + +/* Global declarations. */ + +/* Array of all variables referenced in the function. */ +htab_t referenced_vars; + +/* Default definition for this symbols. If set for symbol, it + means that the first reference to this variable in the function is a + USE or a VUSE. In those cases, the SSA renamer creates an SSA name + for this variable with an empty defining statement. */ +htab_t default_defs; + + +/*--------------------------------------------------------------------------- + Dataflow analysis (DFA) routines +---------------------------------------------------------------------------*/ +/* Find all the variables referenced in the function. This function + builds the global arrays REFERENCED_VARS and CALL_CLOBBERED_VARS. + + Note that this function does not look for statement operands, it simply + determines what variables are referenced in the program and detects + various attributes for each variable used by alias analysis and the + optimizer. */ + +static unsigned int +find_referenced_vars (void) +{ + basic_block bb; + block_stmt_iterator si; + + FOR_EACH_BB (bb) + for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) + { + tree *stmt_p = bsi_stmt_ptr (si); + walk_tree (stmt_p, find_vars_r, NULL, NULL); + } + + return 0; +} + +struct tree_opt_pass pass_referenced_vars = +{ + NULL, /* name */ + NULL, /* gate */ + find_referenced_vars, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + TV_FIND_REFERENCED_VARS, /* tv_id */ + PROP_gimple_leh | PROP_cfg, /* properties_required */ + PROP_referenced_vars, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + 0, /* todo_flags_finish */ + 0 /* letter */ +}; + + +/*--------------------------------------------------------------------------- + Manage annotations +---------------------------------------------------------------------------*/ +/* Create a new annotation for a _DECL node T. */ + +var_ann_t +create_var_ann (tree t) +{ + var_ann_t ann; + + gcc_assert (t); + gcc_assert (DECL_P (t)); + gcc_assert (!t->common.ann || t->common.ann->common.type == VAR_ANN); + + ann = GGC_CNEW (struct var_ann_d); + + ann->common.type = VAR_ANN; + + t->common.ann = (tree_ann_t) ann; + + return ann; +} + +/* Create a new annotation for a FUNCTION_DECL node T. */ + +function_ann_t +create_function_ann (tree t) +{ + function_ann_t ann; + + gcc_assert (t); + gcc_assert (TREE_CODE (t) == FUNCTION_DECL); + gcc_assert (!t->common.ann || t->common.ann->common.type == FUNCTION_ANN); + + ann = ggc_alloc (sizeof (*ann)); + memset ((void *) ann, 0, sizeof (*ann)); + + ann->common.type = FUNCTION_ANN; + + t->common.ann = (tree_ann_t) ann; + + return ann; +} + +/* Create a new annotation for a statement node T. */ + +stmt_ann_t +create_stmt_ann (tree t) +{ + stmt_ann_t ann; + + gcc_assert (is_gimple_stmt (t)); + gcc_assert (!t->common.ann || t->common.ann->common.type == STMT_ANN); + + ann = GGC_CNEW (struct stmt_ann_d); + + ann->common.type = STMT_ANN; + + /* Since we just created the annotation, mark the statement modified. */ + ann->modified = true; + + t->common.ann = (tree_ann_t) ann; + + return ann; +} + +/* Create a new annotation for a tree T. */ + +tree_ann_common_t +create_tree_common_ann (tree t) +{ + tree_ann_common_t ann; + + gcc_assert (t); + gcc_assert (!t->common.ann || t->common.ann->common.type == TREE_ANN_COMMON); + + ann = GGC_CNEW (struct tree_ann_common_d); + + ann->type = TREE_ANN_COMMON; + t->common.ann = (tree_ann_t) ann; + + return ann; +} + +/* Build a temporary. Make sure and register it to be renamed. */ + +tree +make_rename_temp (tree type, const char *prefix) +{ + tree t = create_tmp_var (type, prefix); + + if (TREE_CODE (type) == COMPLEX_TYPE) + DECL_COMPLEX_GIMPLE_REG_P (t) = 1; + + if (referenced_vars) + { + add_referenced_var (t); + mark_sym_for_renaming (t); + } + + return t; +} + + + +/*--------------------------------------------------------------------------- + Debugging functions +---------------------------------------------------------------------------*/ +/* Dump the list of all the referenced variables in the current function to + FILE. */ + +void +dump_referenced_vars (FILE *file) +{ + tree var; + referenced_var_iterator rvi; + + fprintf (file, "\nReferenced variables in %s: %u\n\n", + get_name (current_function_decl), (unsigned) num_referenced_vars); + + FOR_EACH_REFERENCED_VAR (var, rvi) + { + fprintf (file, "Variable: "); + dump_variable (file, var); + fprintf (file, "\n"); + } +} + + +/* Dump the list of all the referenced variables to stderr. */ + +void +debug_referenced_vars (void) +{ + dump_referenced_vars (stderr); +} + + +/* Dump sub-variables for VAR to FILE. */ + +void +dump_subvars_for (FILE *file, tree var) +{ + subvar_t sv = get_subvars_for_var (var); + + if (!sv) + return; + + fprintf (file, "{ "); + + for (; sv; sv = sv->next) + { + print_generic_expr (file, sv->var, dump_flags); + fprintf (file, " "); + } + + fprintf (file, "}"); +} + + +/* Dumb sub-variables for VAR to stderr. */ + +void +debug_subvars_for (tree var) +{ + dump_subvars_for (stderr, var); +} + + +/* Dump variable VAR and its may-aliases to FILE. */ + +void +dump_variable (FILE *file, tree var) +{ + var_ann_t ann; + + if (TREE_CODE (var) == SSA_NAME) + { + if (POINTER_TYPE_P (TREE_TYPE (var))) + dump_points_to_info_for (file, var); + var = SSA_NAME_VAR (var); + } + + if (var == NULL_TREE) + { + fprintf (file, "<nil>"); + return; + } + + print_generic_expr (file, var, dump_flags); + + ann = var_ann (var); + + fprintf (file, ", UID %u", (unsigned) DECL_UID (var)); + + fprintf (file, ", "); + print_generic_expr (file, TREE_TYPE (var), dump_flags); + + if (ann && ann->symbol_mem_tag) + { + fprintf (file, ", symbol memory tag: "); + print_generic_expr (file, ann->symbol_mem_tag, dump_flags); + } + + if (ann && ann->is_aliased) + fprintf (file, ", is aliased"); + + if (TREE_ADDRESSABLE (var)) + fprintf (file, ", is addressable"); + + if (is_global_var (var)) + fprintf (file, ", is global"); + + if (TREE_THIS_VOLATILE (var)) + fprintf (file, ", is volatile"); + + if (is_call_clobbered (var)) + { + fprintf (file, ", call clobbered"); + if (dump_flags & TDF_DETAILS) + { + var_ann_t va = var_ann (var); + unsigned int escape_mask = va->escape_mask; + + fprintf (file, " ("); + if (escape_mask & ESCAPE_STORED_IN_GLOBAL) + fprintf (file, ", stored in global"); + if (escape_mask & ESCAPE_TO_ASM) + fprintf (file, ", goes through ASM"); + if (escape_mask & ESCAPE_TO_CALL) + fprintf (file, ", passed to call"); + if (escape_mask & ESCAPE_BAD_CAST) + fprintf (file, ", bad cast"); + if (escape_mask & ESCAPE_TO_RETURN) + fprintf (file, ", returned from func"); + if (escape_mask & ESCAPE_TO_PURE_CONST) + fprintf (file, ", passed to pure/const"); + if (escape_mask & ESCAPE_IS_GLOBAL) + fprintf (file, ", is global var"); + if (escape_mask & ESCAPE_IS_PARM) + fprintf (file, ", is incoming pointer"); + if (escape_mask & ESCAPE_UNKNOWN) + fprintf (file, ", unknown escape"); + fprintf (file, " )"); + } + } + + if (default_def (var)) + { + fprintf (file, ", default def: "); + print_generic_expr (file, default_def (var), dump_flags); + } + + if (may_aliases (var)) + { + fprintf (file, ", may aliases: "); + dump_may_aliases_for (file, var); + } + + if (get_subvars_for_var (var)) + { + fprintf (file, ", sub-vars: "); + dump_subvars_for (file, var); + } + + fprintf (file, "\n"); +} + + +/* Dump variable VAR and its may-aliases to stderr. */ + +void +debug_variable (tree var) +{ + dump_variable (stderr, var); +} + + +/* Dump various DFA statistics to FILE. */ + +void +dump_dfa_stats (FILE *file) +{ + struct dfa_stats_d dfa_stats; + + unsigned long size, total = 0; + const char * const fmt_str = "%-30s%-13s%12s\n"; + const char * const fmt_str_1 = "%-30s%13lu%11lu%c\n"; + const char * const fmt_str_3 = "%-43s%11lu%c\n"; + const char *funcname + = lang_hooks.decl_printable_name (current_function_decl, 2); + + collect_dfa_stats (&dfa_stats); + + fprintf (file, "\nDFA Statistics for %s\n\n", funcname); + + fprintf (file, "---------------------------------------------------------\n"); + fprintf (file, fmt_str, "", " Number of ", "Memory"); + fprintf (file, fmt_str, "", " instances ", "used "); + fprintf (file, "---------------------------------------------------------\n"); + + size = num_referenced_vars * sizeof (tree); + total += size; + fprintf (file, fmt_str_1, "Referenced variables", (unsigned long)num_referenced_vars, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_stmt_anns * sizeof (struct stmt_ann_d); + total += size; + fprintf (file, fmt_str_1, "Statements annotated", dfa_stats.num_stmt_anns, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_var_anns * sizeof (struct var_ann_d); + total += size; + fprintf (file, fmt_str_1, "Variables annotated", dfa_stats.num_var_anns, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_uses * sizeof (tree *); + total += size; + fprintf (file, fmt_str_1, "USE operands", dfa_stats.num_uses, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_defs * sizeof (tree *); + total += size; + fprintf (file, fmt_str_1, "DEF operands", dfa_stats.num_defs, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_vuses * sizeof (tree *); + total += size; + fprintf (file, fmt_str_1, "VUSE operands", dfa_stats.num_vuses, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_v_may_defs * sizeof (tree *); + total += size; + fprintf (file, fmt_str_1, "V_MAY_DEF operands", dfa_stats.num_v_may_defs, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_v_must_defs * sizeof (tree *); + total += size; + fprintf (file, fmt_str_1, "V_MUST_DEF operands", dfa_stats.num_v_must_defs, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_phis * sizeof (struct tree_phi_node); + total += size; + fprintf (file, fmt_str_1, "PHI nodes", dfa_stats.num_phis, + SCALE (size), LABEL (size)); + + size = dfa_stats.num_phi_args * sizeof (struct phi_arg_d); + total += size; + fprintf (file, fmt_str_1, "PHI arguments", dfa_stats.num_phi_args, + SCALE (size), LABEL (size)); + + fprintf (file, "---------------------------------------------------------\n"); + fprintf (file, fmt_str_3, "Total memory used by DFA/SSA data", SCALE (total), + LABEL (total)); + fprintf (file, "---------------------------------------------------------\n"); + fprintf (file, "\n"); + + if (dfa_stats.num_phis) + fprintf (file, "Average number of arguments per PHI node: %.1f (max: %d)\n", + (float) dfa_stats.num_phi_args / (float) dfa_stats.num_phis, + dfa_stats.max_num_phi_args); + + fprintf (file, "\n"); +} + + +/* Dump DFA statistics on stderr. */ + +void +debug_dfa_stats (void) +{ + dump_dfa_stats (stderr); +} + + +/* Collect DFA statistics and store them in the structure pointed to by + DFA_STATS_P. */ + +static void +collect_dfa_stats (struct dfa_stats_d *dfa_stats_p) +{ + struct pointer_set_t *pset; + basic_block bb; + block_stmt_iterator i; + + gcc_assert (dfa_stats_p); + + memset ((void *)dfa_stats_p, 0, sizeof (struct dfa_stats_d)); + + /* Walk all the trees in the function counting references. Start at + basic block NUM_FIXED_BLOCKS, but don't stop at block boundaries. */ + pset = pointer_set_create (); + + for (i = bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS)); + !bsi_end_p (i); bsi_next (&i)) + walk_tree (bsi_stmt_ptr (i), collect_dfa_stats_r, (void *) dfa_stats_p, + pset); + + pointer_set_destroy (pset); + + FOR_EACH_BB (bb) + { + tree phi; + for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) + { + dfa_stats_p->num_phis++; + dfa_stats_p->num_phi_args += PHI_NUM_ARGS (phi); + if (PHI_NUM_ARGS (phi) > dfa_stats_p->max_num_phi_args) + dfa_stats_p->max_num_phi_args = PHI_NUM_ARGS (phi); + } + } +} + + +/* Callback for walk_tree to collect DFA statistics for a tree and its + children. */ + +static tree +collect_dfa_stats_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED, + void *data) +{ + tree t = *tp; + struct dfa_stats_d *dfa_stats_p = (struct dfa_stats_d *)data; + + if (t->common.ann) + { + switch (ann_type (t->common.ann)) + { + case STMT_ANN: + { + dfa_stats_p->num_stmt_anns++; + dfa_stats_p->num_defs += NUM_SSA_OPERANDS (t, SSA_OP_DEF); + dfa_stats_p->num_uses += NUM_SSA_OPERANDS (t, SSA_OP_USE); + dfa_stats_p->num_v_may_defs += NUM_SSA_OPERANDS (t, SSA_OP_VMAYDEF); + dfa_stats_p->num_vuses += NUM_SSA_OPERANDS (t, SSA_OP_VUSE); + dfa_stats_p->num_v_must_defs += + NUM_SSA_OPERANDS (t, SSA_OP_VMUSTDEF); + break; + } + + case VAR_ANN: + dfa_stats_p->num_var_anns++; + break; + + default: + break; + } + } + + return NULL; +} + + +/*--------------------------------------------------------------------------- + Miscellaneous helpers +---------------------------------------------------------------------------*/ +/* Callback for walk_tree. Used to collect variables referenced in + the function. */ + +static tree +find_vars_r (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED) +{ + /* If T is a regular variable that the optimizers are interested + in, add it to the list of variables. */ + if (SSA_VAR_P (*tp)) + add_referenced_var (*tp); + + /* Type, _DECL and constant nodes have no interesting children. + Ignore them. */ + else if (IS_TYPE_OR_DECL_P (*tp) || CONSTANT_CLASS_P (*tp)) + *walk_subtrees = 0; + + return NULL_TREE; +} + +/* Lookup UID in the referenced_vars hashtable and return the associated + variable. */ + +tree +referenced_var_lookup (unsigned int uid) +{ + struct int_tree_map *h, in; + in.uid = uid; + h = (struct int_tree_map *) htab_find_with_hash (referenced_vars, &in, uid); + gcc_assert (h || uid == 0); + if (h) + return h->to; + return NULL_TREE; +} + +/* Check if TO is in the referenced_vars hash table and insert it if not. + Return true if it required insertion. */ + +bool +referenced_var_check_and_insert (tree to) +{ + struct int_tree_map *h, in; + void **loc; + unsigned int uid = DECL_UID (to); + + in.uid = uid; + in.to = to; + h = (struct int_tree_map *) htab_find_with_hash (referenced_vars, &in, uid); + + if (h) + { + /* DECL_UID has already been entered in the table. Verify that it is + the same entry as TO. See PR 27793. */ + gcc_assert (h->to == to); + return false; + } + + h = GGC_NEW (struct int_tree_map); + h->uid = uid; + h->to = to; + loc = htab_find_slot_with_hash (referenced_vars, h, uid, INSERT); + *(struct int_tree_map **) loc = h; + return true; +} + +/* Lookup VAR UID in the default_defs hashtable and return the associated + variable. */ + +tree +default_def (tree var) +{ + struct int_tree_map *h, in; + gcc_assert (SSA_VAR_P (var)); + in.uid = DECL_UID (var); + h = (struct int_tree_map *) htab_find_with_hash (default_defs, &in, + DECL_UID (var)); + if (h) + return h->to; + return NULL_TREE; +} + +/* Insert the pair VAR's UID, DEF into the default_defs hashtable. */ + +void +set_default_def (tree var, tree def) +{ + struct int_tree_map in; + struct int_tree_map *h; + void **loc; + + gcc_assert (SSA_VAR_P (var)); + in.uid = DECL_UID (var); + if (!def && default_def (var)) + { + loc = htab_find_slot_with_hash (default_defs, &in, DECL_UID (var), INSERT); + htab_remove_elt (default_defs, *loc); + return; + } + gcc_assert (TREE_CODE (def) == SSA_NAME); + loc = htab_find_slot_with_hash (default_defs, &in, DECL_UID (var), INSERT); + /* Default definition might be changed by tail call optimization. */ + if (!*loc) + { + h = GGC_NEW (struct int_tree_map); + h->uid = DECL_UID (var); + h->to = def; + *(struct int_tree_map **) loc = h; + } + else + { + h = (struct int_tree_map *) *loc; + h->to = def; + } +} + +/* Add VAR to the list of referenced variables if it isn't already there. */ + +void +add_referenced_var (tree var) +{ + var_ann_t v_ann; + + v_ann = get_var_ann (var); + gcc_assert (DECL_P (var)); + + /* Insert VAR into the referenced_vars has table if it isn't present. */ + if (referenced_var_check_and_insert (var)) + { + /* This is the first time we found this variable, annotate it with + attributes that are intrinsic to the variable. */ + + /* Tag's don't have DECL_INITIAL. */ + if (MTAG_P (var)) + return; + + /* Scan DECL_INITIAL for pointer variables as they may contain + address arithmetic referencing the address of other + variables. */ + if (DECL_INITIAL (var) + /* Initializers of external variables are not useful to the + optimizers. */ + && !DECL_EXTERNAL (var) + /* It's not necessary to walk the initial value of non-constant + variables because it cannot be propagated by the + optimizers. */ + && (TREE_CONSTANT (var) || TREE_READONLY (var))) + walk_tree (&DECL_INITIAL (var), find_vars_r, NULL, 0); + } +} + + +/* Return the virtual variable associated to the non-scalar variable VAR. */ + +tree +get_virtual_var (tree var) +{ + STRIP_NOPS (var); + + if (TREE_CODE (var) == SSA_NAME) + var = SSA_NAME_VAR (var); + + while (TREE_CODE (var) == REALPART_EXPR || TREE_CODE (var) == IMAGPART_EXPR + || handled_component_p (var)) + var = TREE_OPERAND (var, 0); + + /* Treating GIMPLE registers as virtual variables makes no sense. + Also complain if we couldn't extract a _DECL out of the original + expression. */ + gcc_assert (SSA_VAR_P (var)); + gcc_assert (!is_gimple_reg (var)); + + return var; +} + +/* Mark all the non-SSA variables found in STMT's operands to be + processed by update_ssa. */ + +void +mark_new_vars_to_rename (tree stmt) +{ + ssa_op_iter iter; + tree val; + bitmap vars_in_vops_to_rename; + bool found_exposed_symbol = false; + int v_may_defs_before, v_may_defs_after; + int v_must_defs_before, v_must_defs_after; + + if (TREE_CODE (stmt) == PHI_NODE) + return; + + get_stmt_ann (stmt); + vars_in_vops_to_rename = BITMAP_ALLOC (NULL); + + /* Before re-scanning the statement for operands, mark the existing + virtual operands to be renamed again. We do this because when new + symbols are exposed, the virtual operands that were here before due to + aliasing will probably be removed by the call to get_stmt_operand. + Therefore, we need to flag them to be renamed beforehand. + + We flag them in a separate bitmap because we don't really want to + rename them if there are not any newly exposed symbols in the + statement operands. */ + v_may_defs_before = NUM_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF); + v_must_defs_before = NUM_SSA_OPERANDS (stmt, SSA_OP_VMUSTDEF); + + FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, + SSA_OP_VMAYDEF | SSA_OP_VUSE | SSA_OP_VMUSTDEF) + { + if (!DECL_P (val)) + val = SSA_NAME_VAR (val); + bitmap_set_bit (vars_in_vops_to_rename, DECL_UID (val)); + } + + /* Now force an operand re-scan on the statement and mark any newly + exposed variables. */ + update_stmt (stmt); + + v_may_defs_after = NUM_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF); + v_must_defs_after = NUM_SSA_OPERANDS (stmt, SSA_OP_VMUSTDEF); + + FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_ALL_OPERANDS) + if (DECL_P (val)) + { + found_exposed_symbol = true; + mark_sym_for_renaming (val); + } + + /* If we found any newly exposed symbols, or if there are fewer VDEF + operands in the statement, add the variables we had set in + VARS_IN_VOPS_TO_RENAME to VARS_TO_RENAME. We need to check for + vanishing VDEFs because in those cases, the names that were formerly + generated by this statement are not going to be available anymore. */ + if (found_exposed_symbol + || v_may_defs_before > v_may_defs_after + || v_must_defs_before > v_must_defs_after) + mark_set_for_renaming (vars_in_vops_to_rename); + + BITMAP_FREE (vars_in_vops_to_rename); +} + +/* Find all variables within the gimplified statement that were not previously + visible to the function and add them to the referenced variables list. */ + +static tree +find_new_referenced_vars_1 (tree *tp, int *walk_subtrees, + void *data ATTRIBUTE_UNUSED) +{ + tree t = *tp; + + if (TREE_CODE (t) == VAR_DECL && !var_ann (t)) + { + add_referenced_var (t); + mark_sym_for_renaming (t); + } + + if (IS_TYPE_OR_DECL_P (t)) + *walk_subtrees = 0; + + return NULL; +} + +void +find_new_referenced_vars (tree *stmt_p) +{ + walk_tree (stmt_p, find_new_referenced_vars_1, NULL, NULL); +} + + +/* If REF is a handled component reference for a structure, return the + base variable. The access range is delimited by bit positions *POFFSET and + *POFFSET + *PMAX_SIZE. The access size is *PSIZE bits. If either + *PSIZE or *PMAX_SIZE is -1, they could not be determined. If *PSIZE + and *PMAX_SIZE are equal, the access is non-variable. */ + +tree +get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset, + HOST_WIDE_INT *psize, + HOST_WIDE_INT *pmax_size) +{ + HOST_WIDE_INT bitsize = -1; + HOST_WIDE_INT maxsize = -1; + tree size_tree = NULL_TREE; + tree bit_offset = bitsize_zero_node; + bool seen_variable_array_ref = false; + + gcc_assert (!SSA_VAR_P (exp)); + + /* First get the final access size from just the outermost expression. */ + if (TREE_CODE (exp) == COMPONENT_REF) + size_tree = DECL_SIZE (TREE_OPERAND (exp, 1)); + else if (TREE_CODE (exp) == BIT_FIELD_REF) + size_tree = TREE_OPERAND (exp, 1); + else + { + enum machine_mode mode = TYPE_MODE (TREE_TYPE (exp)); + if (mode == BLKmode) + size_tree = TYPE_SIZE (TREE_TYPE (exp)); + else + bitsize = GET_MODE_BITSIZE (mode); + } + if (size_tree != NULL_TREE) + { + if (! host_integerp (size_tree, 1)) + bitsize = -1; + else + bitsize = TREE_INT_CST_LOW (size_tree); + } + + /* Initially, maxsize is the same as the accessed element size. + In the following it will only grow (or become -1). */ + maxsize = bitsize; + + /* Compute cumulative bit-offset for nested component-refs and array-refs, + and find the ultimate containing object. */ + while (1) + { + switch (TREE_CODE (exp)) + { + case BIT_FIELD_REF: + bit_offset = size_binop (PLUS_EXPR, bit_offset, + TREE_OPERAND (exp, 2)); + break; + + case COMPONENT_REF: + { + tree field = TREE_OPERAND (exp, 1); + tree this_offset = component_ref_field_offset (exp); + + if (this_offset && TREE_CODE (this_offset) == INTEGER_CST) + { + this_offset = size_binop (MULT_EXPR, + fold_convert (bitsizetype, + this_offset), + bitsize_unit_node); + bit_offset = size_binop (PLUS_EXPR, + bit_offset, this_offset); + bit_offset = size_binop (PLUS_EXPR, bit_offset, + DECL_FIELD_BIT_OFFSET (field)); + } + else + { + tree csize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0))); + /* We need to adjust maxsize to the whole structure bitsize. + But we can subtract any constant offset seen sofar, + because that would get us out of the structure otherwise. */ + if (maxsize != -1 + && csize && host_integerp (csize, 1)) + { + maxsize = (TREE_INT_CST_LOW (csize) + - TREE_INT_CST_LOW (bit_offset)); + } + else + maxsize = -1; + } + } + break; + + case ARRAY_REF: + case ARRAY_RANGE_REF: + { + tree index = TREE_OPERAND (exp, 1); + tree low_bound = array_ref_low_bound (exp); + tree unit_size = array_ref_element_size (exp); + + if (! integer_zerop (low_bound)) + index = fold_build2 (MINUS_EXPR, TREE_TYPE (index), + index, low_bound); + index = size_binop (MULT_EXPR, + fold_convert (sizetype, index), unit_size); + if (TREE_CODE (index) == INTEGER_CST) + { + index = size_binop (MULT_EXPR, + fold_convert (bitsizetype, index), + bitsize_unit_node); + bit_offset = size_binop (PLUS_EXPR, bit_offset, index); + + /* An array ref with a constant index up in the structure + hierarchy will constrain the size of any variable array ref + lower in the access hierarchy. */ + seen_variable_array_ref = false; + } + else + { + tree asize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0))); + /* We need to adjust maxsize to the whole array bitsize. + But we can subtract any constant offset seen sofar, + because that would get us outside of the array otherwise. */ + if (maxsize != -1 + && asize && host_integerp (asize, 1)) + { + maxsize = (TREE_INT_CST_LOW (asize) + - TREE_INT_CST_LOW (bit_offset)); + } + else + maxsize = -1; + + /* Remember that we have seen an array ref with a variable + index. */ + seen_variable_array_ref = true; + } + } + break; + + case REALPART_EXPR: + break; + + case IMAGPART_EXPR: + bit_offset = size_binop (PLUS_EXPR, bit_offset, + bitsize_int (bitsize)); + break; + + case VIEW_CONVERT_EXPR: + /* ??? We probably should give up here and bail out. */ + break; + + default: + goto done; + } + + exp = TREE_OPERAND (exp, 0); + } + done: + + /* We need to deal with variable arrays ending structures such as + struct { int length; int a[1]; } x; x.a[d] + struct { struct { int a; int b; } a[1]; } x; x.a[d].a + struct { struct { int a[1]; } a[1]; } x; x.a[0][d], x.a[d][0] + where we do not know maxsize for variable index accesses to + the array. The simplest way to conservatively deal with this + is to punt in the case that offset + maxsize reaches the + base type boundary. */ + if (seen_variable_array_ref + && maxsize != -1 + && host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1) + && TREE_INT_CST_LOW (bit_offset) + maxsize + == TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp)))) + maxsize = -1; + + /* ??? Due to negative offsets in ARRAY_REF we can end up with + negative bit_offset here. We might want to store a zero offset + in this case. */ + *poffset = TREE_INT_CST_LOW (bit_offset); + *psize = bitsize; + *pmax_size = maxsize; + + return exp; +} |
