44d974b5d2
From-SVN: r123022
2177 lines
60 KiB
C
2177 lines
60 KiB
C
/* Type based alias analysis.
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Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
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Contributed by Kenneth Zadeck <zadeck@naturalbridge.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 it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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 the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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/* This pass determines which types in the program contain only
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instances that are completely encapsulated by the compilation unit.
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Those types that are encapsulated must also pass the further
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requirement that there be no bad operations on any instances of
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those types.
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A great deal of freedom in compilation is allowed for the instances
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of those types that pass these conditions.
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*/
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/* The code in this module is called by the ipa pass manager. It
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should be one of the later passes since its information is used by
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the rest of the compilation. */
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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 "tree-flow.h"
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#include "tree-inline.h"
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#include "tree-pass.h"
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#include "langhooks.h"
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#include "pointer-set.h"
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#include "ggc.h"
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#include "ipa-utils.h"
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#include "ipa-type-escape.h"
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#include "c-common.h"
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#include "tree-gimple.h"
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#include "cgraph.h"
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#include "output.h"
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#include "flags.h"
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#include "timevar.h"
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#include "diagnostic.h"
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#include "langhooks.h"
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/* Some of the aliasing is called very early, before this phase is
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called. To assure that this is not a problem, we keep track of if
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this phase has been run. */
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static bool initialized = false;
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/* Scratch bitmap for avoiding work. */
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static bitmap been_there_done_that;
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static bitmap bitmap_tmp;
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/* There are two levels of escape that types can undergo.
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EXPOSED_PARAMETER - some instance of the variable is
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passed by value into an externally visible function or some
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instance of the variable is passed out of an externally visible
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function as a return value. In this case any of the fields of the
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variable that are pointer types end up having their types marked as
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FULL_ESCAPE.
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FULL_ESCAPE - when bad things happen to good types. One of the
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following things happens to the type: (a) either an instance of the
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variable has its address passed to an externally visible function,
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(b) the address is taken and some bad cast happens to the address
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or (c) explicit arithmetic is done to the address.
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*/
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enum escape_t
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{
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EXPOSED_PARAMETER,
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FULL_ESCAPE
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};
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/* The following two bit vectors global_types_* correspond to
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previous cases above. During the analysis phase, a bit is set in
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one of these vectors if an operation of the offending class is
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discovered to happen on the associated type. */
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static bitmap global_types_exposed_parameter;
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static bitmap global_types_full_escape;
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/* All of the types seen in this compilation unit. */
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static bitmap global_types_seen;
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/* Reverse map to take a canon uid and map it to a canon type. Uid's
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are never manipulated unless they are associated with a canon
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type. */
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static splay_tree uid_to_canon_type;
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/* Internal structure of type mapping code. This maps a canon type
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name to its canon type. */
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static splay_tree all_canon_types;
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/* Map from type clones to the single canon type. */
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static splay_tree type_to_canon_type;
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/* A splay tree of bitmaps. An element X in the splay tree has a bit
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set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (Y)) if there was
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an operation in the program of the form "&X.Y". */
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static splay_tree uid_to_addressof_down_map;
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/* A splay tree of bitmaps. An element Y in the splay tree has a bit
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set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (X)) if there was
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an operation in the program of the form "&X.Y". */
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static splay_tree uid_to_addressof_up_map;
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/* Tree to hold the subtype maps used to mark subtypes of escaped
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types. */
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static splay_tree uid_to_subtype_map;
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/* Records tree nodes seen in cgraph_create_edges. Simply using
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walk_tree_without_duplicates doesn't guarantee each node is visited
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once because it gets a new htab upon each recursive call from
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scan_for_refs. */
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static struct pointer_set_t *visited_nodes;
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/* Visited stmts by walk_use_def_chains function because it's called
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recursively. */
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static struct pointer_set_t *visited_stmts;
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static bitmap_obstack ipa_obstack;
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/* Static functions from this file that are used
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before being defined. */
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static unsigned int look_for_casts (tree lhs ATTRIBUTE_UNUSED, tree);
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static bool is_cast_from_non_pointer (tree, tree, void *);
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/* Get the name of TYPE or return the string "<UNNAMED>". */
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static char*
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get_name_of_type (tree type)
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{
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tree name = TYPE_NAME (type);
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if (!name)
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/* Unnamed type, do what you like here. */
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return (char*)"<UNNAMED>";
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/* It will be a TYPE_DECL in the case of a typedef, otherwise, an
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identifier_node */
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if (TREE_CODE (name) == TYPE_DECL)
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{
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/* Each DECL has a DECL_NAME field which contains an
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IDENTIFIER_NODE. (Some decls, most often labels, may have
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zero as the DECL_NAME). */
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if (DECL_NAME (name))
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return (char*)IDENTIFIER_POINTER (DECL_NAME (name));
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else
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/* Unnamed type, do what you like here. */
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return (char*)"<UNNAMED>";
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}
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else if (TREE_CODE (name) == IDENTIFIER_NODE)
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return (char*)IDENTIFIER_POINTER (name);
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else
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return (char*)"<UNNAMED>";
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}
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struct type_brand_s
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{
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char* name;
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int seq;
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};
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/* Splay tree comparison function on type_brand_s structures. */
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static int
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compare_type_brand (splay_tree_key sk1, splay_tree_key sk2)
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{
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struct type_brand_s * k1 = (struct type_brand_s *) sk1;
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struct type_brand_s * k2 = (struct type_brand_s *) sk2;
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int value = strcmp(k1->name, k2->name);
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if (value == 0)
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return k2->seq - k1->seq;
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else
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return value;
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}
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/* All of the "unique_type" code is a hack to get around the sleazy
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implementation used to compile more than file. Currently gcc does
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not get rid of multiple instances of the same type that have been
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collected from different compilation units. */
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/* This is a trivial algorithm for removing duplicate types. This
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would not work for any language that used structural equivalence as
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the basis of its type system. */
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/* Return either TYPE if this is first time TYPE has been seen an
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compatible TYPE that has already been processed. */
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static tree
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discover_unique_type (tree type)
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{
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struct type_brand_s * brand = XNEW (struct type_brand_s);
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int i = 0;
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splay_tree_node result;
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brand->name = get_name_of_type (type);
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while (1)
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{
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brand->seq = i++;
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result = splay_tree_lookup (all_canon_types, (splay_tree_key) brand);
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if (result)
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{
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/* Create an alias since this is just the same as
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other_type. */
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tree other_type = (tree) result->value;
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if (lang_hooks.types_compatible_p (type, other_type) == 1)
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{
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free (brand);
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/* Insert this new type as an alias for other_type. */
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splay_tree_insert (type_to_canon_type,
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(splay_tree_key) type,
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(splay_tree_value) other_type);
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return other_type;
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}
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/* Not compatible, look for next instance with same name. */
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}
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else
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{
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/* No more instances, create new one since this is the first
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time we saw this type. */
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brand->seq = i++;
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/* Insert the new brand. */
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splay_tree_insert (all_canon_types,
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(splay_tree_key) brand,
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(splay_tree_value) type);
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/* Insert this new type as an alias for itself. */
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splay_tree_insert (type_to_canon_type,
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(splay_tree_key) type,
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(splay_tree_value) type);
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/* Insert the uid for reverse lookup; */
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splay_tree_insert (uid_to_canon_type,
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(splay_tree_key) TYPE_UID (type),
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(splay_tree_value) type);
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bitmap_set_bit (global_types_seen, TYPE_UID (type));
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return type;
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}
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}
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}
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/* Return true if TYPE is one of the type classes that we are willing
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to analyze. This skips the goofy types like arrays of pointers to
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methods. */
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static bool
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type_to_consider (tree type)
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{
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/* Strip the *'s off. */
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type = TYPE_MAIN_VARIANT (type);
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while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE)
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type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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switch (TREE_CODE (type))
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{
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case BOOLEAN_TYPE:
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case COMPLEX_TYPE:
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case ENUMERAL_TYPE:
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case INTEGER_TYPE:
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case QUAL_UNION_TYPE:
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case REAL_TYPE:
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case RECORD_TYPE:
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case UNION_TYPE:
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case VECTOR_TYPE:
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case VOID_TYPE:
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return true;
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default:
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return false;
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}
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}
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/* Get the canon type of TYPE. If SEE_THRU_PTRS is true, remove all
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the POINTER_TOs and if SEE_THRU_ARRAYS is true, remove all of the
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ARRAY_OFs and POINTER_TOs. */
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static tree
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get_canon_type (tree type, bool see_thru_ptrs, bool see_thru_arrays)
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{
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splay_tree_node result;
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/* Strip the *'s off. */
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if (!type || !type_to_consider (type))
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return NULL;
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type = TYPE_MAIN_VARIANT (type);
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if (see_thru_arrays)
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while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE)
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type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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else if (see_thru_ptrs)
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while (POINTER_TYPE_P (type))
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type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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result = splay_tree_lookup(type_to_canon_type, (splay_tree_key) type);
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if (result == NULL)
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return discover_unique_type (type);
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else return (tree) result->value;
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}
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/* Same as GET_CANON_TYPE, except return the TYPE_ID rather than the
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TYPE. */
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static int
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get_canon_type_uid (tree type, bool see_thru_ptrs, bool see_thru_arrays)
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{
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type = get_canon_type (type, see_thru_ptrs, see_thru_arrays);
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if (type)
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return TYPE_UID(type);
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else return 0;
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}
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/* Return 0 if TYPE is a record or union type. Return a positive
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number if TYPE is a pointer to a record or union. The number is
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the number of pointer types stripped to get to the record or union
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type. Return -1 if TYPE is none of the above. */
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int
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ipa_type_escape_star_count_of_interesting_type (tree type)
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{
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int count = 0;
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/* Strip the *'s off. */
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if (!type)
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return -1;
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type = TYPE_MAIN_VARIANT (type);
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while (POINTER_TYPE_P (type))
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{
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type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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count++;
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}
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/* We are interested in records, and unions only. */
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if (TREE_CODE (type) == RECORD_TYPE
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|| TREE_CODE (type) == QUAL_UNION_TYPE
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|| TREE_CODE (type) == UNION_TYPE)
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return count;
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else
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return -1;
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}
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/* Return 0 if TYPE is a record or union type. Return a positive
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number if TYPE is a pointer to a record or union. The number is
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the number of pointer types stripped to get to the record or union
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type. Return -1 if TYPE is none of the above. */
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int
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ipa_type_escape_star_count_of_interesting_or_array_type (tree type)
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{
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int count = 0;
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/* Strip the *'s off. */
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if (!type)
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return -1;
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type = TYPE_MAIN_VARIANT (type);
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while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE)
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{
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type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
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count++;
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}
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/* We are interested in records, and unions only. */
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if (TREE_CODE (type) == RECORD_TYPE
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|| TREE_CODE (type) == QUAL_UNION_TYPE
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|| TREE_CODE (type) == UNION_TYPE)
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return count;
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else
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return -1;
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}
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/* Return true if the record, or union TYPE passed in escapes this
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compilation unit. Note that all of the pointer-to's are removed
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before testing since these may not be correct. */
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bool
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ipa_type_escape_type_contained_p (tree type)
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{
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if (!initialized)
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return false;
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return !bitmap_bit_p (global_types_full_escape,
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get_canon_type_uid (type, true, false));
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}
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/* Return true if a modification to a field of type FIELD_TYPE cannot
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clobber a record of RECORD_TYPE. */
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bool
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ipa_type_escape_field_does_not_clobber_p (tree record_type, tree field_type)
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{
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splay_tree_node result;
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int uid;
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if (!initialized)
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return false;
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|
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/* Strip off all of the pointer tos on the record type. Strip the
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same number of pointer tos from the field type. If the field
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type has fewer, it could not have been aliased. */
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record_type = TYPE_MAIN_VARIANT (record_type);
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field_type = TYPE_MAIN_VARIANT (field_type);
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while (POINTER_TYPE_P (record_type))
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{
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record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type));
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if (POINTER_TYPE_P (field_type))
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field_type = TYPE_MAIN_VARIANT (TREE_TYPE (field_type));
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else
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/* However, if field_type is a union, this quick test is not
|
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correct since one of the variants of the union may be a
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pointer to type and we cannot see across that here. So we
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just strip the remaining pointer tos off the record type
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and fall thru to the more precise code. */
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if (TREE_CODE (field_type) == QUAL_UNION_TYPE
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|| TREE_CODE (field_type) == UNION_TYPE)
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{
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while (POINTER_TYPE_P (record_type))
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record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type));
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||
break;
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||
}
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else
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return true;
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}
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record_type = get_canon_type (record_type, true, true);
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||
/* The record type must be contained. The field type may
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escape. */
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if (!ipa_type_escape_type_contained_p (record_type))
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return false;
|
||
|
||
uid = TYPE_UID (record_type);
|
||
result = splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid);
|
||
|
||
if (result)
|
||
{
|
||
bitmap field_type_map = (bitmap) result->value;
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||
uid = get_canon_type_uid (field_type, true, true);
|
||
/* If the bit is there, the address was taken. If not, it
|
||
wasn't. */
|
||
return !bitmap_bit_p (field_type_map, uid);
|
||
}
|
||
else
|
||
/* No bitmap means no addresses were taken. */
|
||
return true;
|
||
}
|
||
|
||
|
||
/* Add TYPE to the suspect type set. Return true if the bit needed to
|
||
be marked. */
|
||
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||
static tree
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||
mark_type (tree type, enum escape_t escape_status)
|
||
{
|
||
bitmap map = NULL;
|
||
int uid;
|
||
|
||
type = get_canon_type (type, true, true);
|
||
if (!type)
|
||
return NULL;
|
||
|
||
switch (escape_status)
|
||
{
|
||
case EXPOSED_PARAMETER:
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||
map = global_types_exposed_parameter;
|
||
break;
|
||
case FULL_ESCAPE:
|
||
map = global_types_full_escape;
|
||
break;
|
||
}
|
||
|
||
uid = TYPE_UID (type);
|
||
if (bitmap_bit_p (map, uid))
|
||
return type;
|
||
else
|
||
{
|
||
bitmap_set_bit (map, uid);
|
||
if (escape_status == FULL_ESCAPE)
|
||
{
|
||
/* Efficiency hack. When things are bad, do not mess around
|
||
with this type anymore. */
|
||
bitmap_set_bit (global_types_exposed_parameter, uid);
|
||
}
|
||
}
|
||
return type;
|
||
}
|
||
|
||
/* Add interesting TYPE to the suspect type set. If the set is
|
||
EXPOSED_PARAMETER and the TYPE is a pointer type, the set is
|
||
changed to FULL_ESCAPE. */
|
||
|
||
static void
|
||
mark_interesting_type (tree type, enum escape_t escape_status)
|
||
{
|
||
if (!type) return;
|
||
if (ipa_type_escape_star_count_of_interesting_type (type) >= 0)
|
||
{
|
||
if ((escape_status == EXPOSED_PARAMETER)
|
||
&& POINTER_TYPE_P (type))
|
||
/* EXPOSED_PARAMETERs are only structs or unions are passed by
|
||
value. Anything passed by reference to an external
|
||
function fully exposes the type. */
|
||
mark_type (type, FULL_ESCAPE);
|
||
else
|
||
mark_type (type, escape_status);
|
||
}
|
||
}
|
||
|
||
/* Return true if PARENT is supertype of CHILD. Both types must be
|
||
known to be structures or unions. */
|
||
|
||
static bool
|
||
parent_type_p (tree parent, tree child)
|
||
{
|
||
int i;
|
||
tree binfo, base_binfo;
|
||
if (TYPE_BINFO (parent))
|
||
for (binfo = TYPE_BINFO (parent), i = 0;
|
||
BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
|
||
{
|
||
tree binfotype = BINFO_TYPE (base_binfo);
|
||
if (binfotype == child)
|
||
return true;
|
||
else if (parent_type_p (binfotype, child))
|
||
return true;
|
||
}
|
||
if (TREE_CODE (parent) == UNION_TYPE
|
||
|| TREE_CODE (parent) == QUAL_UNION_TYPE)
|
||
{
|
||
tree field;
|
||
/* Search all of the variants in the union to see if one of them
|
||
is the child. */
|
||
for (field = TYPE_FIELDS (parent);
|
||
field;
|
||
field = TREE_CHAIN (field))
|
||
{
|
||
tree field_type;
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
field_type = TREE_TYPE (field);
|
||
if (field_type == child)
|
||
return true;
|
||
}
|
||
|
||
/* If we did not find it, recursively ask the variants if one of
|
||
their children is the child type. */
|
||
for (field = TYPE_FIELDS (parent);
|
||
field;
|
||
field = TREE_CHAIN (field))
|
||
{
|
||
tree field_type;
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
field_type = TREE_TYPE (field);
|
||
if (TREE_CODE (field_type) == RECORD_TYPE
|
||
|| TREE_CODE (field_type) == QUAL_UNION_TYPE
|
||
|| TREE_CODE (field_type) == UNION_TYPE)
|
||
if (parent_type_p (field_type, child))
|
||
return true;
|
||
}
|
||
}
|
||
|
||
if (TREE_CODE (parent) == RECORD_TYPE)
|
||
{
|
||
tree field;
|
||
for (field = TYPE_FIELDS (parent);
|
||
field;
|
||
field = TREE_CHAIN (field))
|
||
{
|
||
tree field_type;
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
field_type = TREE_TYPE (field);
|
||
if (field_type == child)
|
||
return true;
|
||
/* You can only cast to the first field so if it does not
|
||
match, quit. */
|
||
if (TREE_CODE (field_type) == RECORD_TYPE
|
||
|| TREE_CODE (field_type) == QUAL_UNION_TYPE
|
||
|| TREE_CODE (field_type) == UNION_TYPE)
|
||
{
|
||
if (parent_type_p (field_type, child))
|
||
return true;
|
||
else
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/* Return the number of pointer tos for TYPE and return TYPE with all
|
||
of these stripped off. */
|
||
|
||
static int
|
||
count_stars (tree* type_ptr)
|
||
{
|
||
tree type = *type_ptr;
|
||
int i = 0;
|
||
type = TYPE_MAIN_VARIANT (type);
|
||
while (POINTER_TYPE_P (type))
|
||
{
|
||
type = TYPE_MAIN_VARIANT (TREE_TYPE (type));
|
||
i++;
|
||
}
|
||
|
||
*type_ptr = type;
|
||
return i;
|
||
}
|
||
|
||
enum cast_type {
|
||
CT_UP = 0x1,
|
||
CT_DOWN = 0x2,
|
||
CT_SIDEWAYS = 0x4,
|
||
CT_USELESS = 0x8,
|
||
CT_FROM_P_BAD = 0x10,
|
||
CT_FROM_NON_P = 0x20,
|
||
CT_TO_NON_INTER = 0x40,
|
||
CT_FROM_MALLOC = 0x80,
|
||
CT_NO_CAST = 0x100
|
||
};
|
||
|
||
/* Check the cast FROM_TYPE to TO_TYPE. This function requires that
|
||
the two types have already passed the
|
||
ipa_type_escape_star_count_of_interesting_type test. */
|
||
|
||
static enum cast_type
|
||
check_cast_type (tree to_type, tree from_type)
|
||
{
|
||
int to_stars = count_stars (&to_type);
|
||
int from_stars = count_stars (&from_type);
|
||
if (to_stars != from_stars)
|
||
return CT_SIDEWAYS;
|
||
|
||
if (to_type == from_type)
|
||
return CT_USELESS;
|
||
|
||
if (parent_type_p (to_type, from_type)) return CT_UP;
|
||
if (parent_type_p (from_type, to_type)) return CT_DOWN;
|
||
return CT_SIDEWAYS;
|
||
}
|
||
|
||
/* This function returns non-zero if VAR is result of call
|
||
to malloc function. */
|
||
|
||
static bool
|
||
is_malloc_result (tree var)
|
||
{
|
||
tree def_stmt;
|
||
tree rhs;
|
||
int flags;
|
||
|
||
if (!var)
|
||
return false;
|
||
|
||
if (SSA_NAME_IS_DEFAULT_DEF (var))
|
||
return false;
|
||
|
||
def_stmt = SSA_NAME_DEF_STMT (var);
|
||
|
||
if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
|
||
return false;
|
||
|
||
if (var != GIMPLE_STMT_OPERAND (def_stmt, 0))
|
||
return false;
|
||
|
||
rhs = get_call_expr_in (def_stmt);
|
||
|
||
if (!rhs)
|
||
return false;
|
||
|
||
flags = call_expr_flags (rhs);
|
||
|
||
return ((flags & ECF_MALLOC) != 0);
|
||
|
||
}
|
||
|
||
/* Check a cast FROM this variable, TO_TYPE. Mark the escaping types
|
||
if appropriate. Returns cast_type as detected. */
|
||
|
||
static enum cast_type
|
||
check_cast (tree to_type, tree from)
|
||
{
|
||
tree from_type = get_canon_type (TREE_TYPE (from), false, false);
|
||
bool to_interesting_type, from_interesting_type;
|
||
enum cast_type cast = CT_NO_CAST;
|
||
|
||
to_type = get_canon_type (to_type, false, false);
|
||
if (!from_type || !to_type || from_type == to_type)
|
||
return cast;
|
||
|
||
to_interesting_type =
|
||
ipa_type_escape_star_count_of_interesting_type (to_type) >= 0;
|
||
from_interesting_type =
|
||
ipa_type_escape_star_count_of_interesting_type (from_type) >= 0;
|
||
|
||
if (to_interesting_type)
|
||
if (from_interesting_type)
|
||
{
|
||
/* Both types are interesting. This can be one of four types
|
||
of cast: useless, up, down, or sideways. We do not care
|
||
about up or useless. Sideways casts are always bad and
|
||
both sides get marked as escaping. Downcasts are not
|
||
interesting here because if type is marked as escaping, all
|
||
of its subtypes escape. */
|
||
cast = check_cast_type (to_type, from_type);
|
||
switch (cast)
|
||
{
|
||
case CT_UP:
|
||
case CT_USELESS:
|
||
case CT_DOWN:
|
||
break;
|
||
|
||
case CT_SIDEWAYS:
|
||
mark_type (to_type, FULL_ESCAPE);
|
||
mark_type (from_type, FULL_ESCAPE);
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* This code excludes two cases from marking as escaped:
|
||
|
||
1. if this is a cast of index of array of structures/unions
|
||
that happens before accessing array element, we should not
|
||
mark it as escaped.
|
||
2. if this is a cast from the local that is a result from a
|
||
call to malloc, do not mark the cast as bad.
|
||
|
||
*/
|
||
|
||
if (POINTER_TYPE_P (to_type) && !POINTER_TYPE_P (from_type))
|
||
cast = CT_FROM_NON_P;
|
||
else if (TREE_CODE (from) == SSA_NAME
|
||
&& is_malloc_result (from))
|
||
cast = CT_FROM_MALLOC;
|
||
else
|
||
{
|
||
cast = CT_FROM_P_BAD;
|
||
mark_type (to_type, FULL_ESCAPE);
|
||
}
|
||
}
|
||
else if (from_interesting_type)
|
||
{
|
||
mark_type (from_type, FULL_ESCAPE);
|
||
cast = CT_TO_NON_INTER;
|
||
}
|
||
|
||
return cast;
|
||
}
|
||
|
||
typedef struct cast
|
||
{
|
||
int type;
|
||
tree stmt;
|
||
}cast_t;
|
||
|
||
/* This function is a callback for walk_tree called from
|
||
is_cast_from_non_pointer. The data->type is set to be:
|
||
|
||
0 - if there is no cast
|
||
number - the number of casts from non-pointer type
|
||
-1 - if there is a cast that makes the type to escape
|
||
|
||
If data->type = number, then data->stmt will contain the
|
||
last casting stmt met in traversing. */
|
||
|
||
static tree
|
||
is_cast_from_non_pointer_1 (tree *tp, int *walk_subtrees, void *data)
|
||
{
|
||
tree def_stmt = *tp;
|
||
|
||
|
||
if (pointer_set_insert (visited_stmts, def_stmt))
|
||
{
|
||
*walk_subtrees = 0;
|
||
return NULL;
|
||
}
|
||
|
||
switch (TREE_CODE (def_stmt))
|
||
{
|
||
case GIMPLE_MODIFY_STMT:
|
||
{
|
||
use_operand_p use_p;
|
||
ssa_op_iter iter;
|
||
tree lhs = GIMPLE_STMT_OPERAND (def_stmt, 0);
|
||
tree rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
|
||
|
||
unsigned int cast = look_for_casts (lhs, rhs);
|
||
/* Check that only one cast happened, and it's of
|
||
non-pointer type. */
|
||
if ((cast & CT_FROM_NON_P) == (CT_FROM_NON_P)
|
||
&& (cast & ~(CT_FROM_NON_P)) == 0)
|
||
{
|
||
((cast_t *)data)->stmt = def_stmt;
|
||
((cast_t *)data)->type++;
|
||
|
||
FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES)
|
||
{
|
||
walk_use_def_chains (USE_FROM_PTR (use_p), is_cast_from_non_pointer,
|
||
data, false);
|
||
if (((cast_t*)data)->type == -1)
|
||
return def_stmt;
|
||
}
|
||
}
|
||
|
||
/* Check that there is no cast, or cast is not harmful. */
|
||
else if ((cast & CT_NO_CAST) == (CT_NO_CAST)
|
||
|| (cast & CT_DOWN) == (CT_DOWN)
|
||
|| (cast & CT_UP) == (CT_UP)
|
||
|| (cast & CT_USELESS) == (CT_USELESS)
|
||
|| (cast & CT_FROM_MALLOC) == (CT_FROM_MALLOC))
|
||
{
|
||
FOR_EACH_SSA_USE_OPERAND (use_p, def_stmt, iter, SSA_OP_ALL_USES)
|
||
{
|
||
walk_use_def_chains (USE_FROM_PTR (use_p), is_cast_from_non_pointer,
|
||
data, false);
|
||
if (((cast_t*)data)->type == -1)
|
||
return def_stmt;
|
||
}
|
||
}
|
||
|
||
/* The cast is harmful. */
|
||
else
|
||
{
|
||
((cast_t *)data)->type = -1;
|
||
return def_stmt;
|
||
}
|
||
|
||
*walk_subtrees = 0;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
{
|
||
*walk_subtrees = 0;
|
||
break;
|
||
}
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* This function is a callback for walk_use_def_chains function called
|
||
from is_array_access_through_pointer_and_index. */
|
||
|
||
static bool
|
||
is_cast_from_non_pointer (tree var, tree def_stmt, void *data)
|
||
{
|
||
|
||
if (!def_stmt || !var)
|
||
return false;
|
||
|
||
if (TREE_CODE (def_stmt) == PHI_NODE)
|
||
return false;
|
||
|
||
if (SSA_NAME_IS_DEFAULT_DEF (var))
|
||
return false;
|
||
|
||
walk_tree (&def_stmt, is_cast_from_non_pointer_1, data, NULL);
|
||
if (((cast_t*)data)->type == -1)
|
||
return true;
|
||
|
||
return false;
|
||
}
|
||
|
||
/* When array element a_p[i] is accessed through the pointer a_p
|
||
and index i, it's translated into the following sequence
|
||
in gimple:
|
||
|
||
i.1_5 = (unsigned int) i_1;
|
||
D.1605_6 = i.1_5 * 16;
|
||
D.1606_7 = (struct str_t *) D.1605_6;
|
||
a_p.2_8 = a_p;
|
||
D.1608_9 = D.1606_7 + a_p.2_8;
|
||
|
||
OP0 and OP1 are of the same pointer types and stand for
|
||
D.1606_7 and a_p.2_8 or vise versa.
|
||
|
||
This function checks that:
|
||
|
||
1. one of OP0 and OP1 (D.1606_7) has passed only one cast from
|
||
non-pointer type (D.1606_7 = (struct str_t *) D.1605_6;).
|
||
|
||
2. one of OP0 and OP1 which has passed the cast from
|
||
non-pointer type (D.1606_7), is actually generated by multiplication of
|
||
index by size of type to which both OP0 and OP1 point to
|
||
(in this case D.1605_6 = i.1_5 * 16; ).
|
||
|
||
3. an address of def of the var to which was made cast (D.1605_6)
|
||
was not taken.(How can it happen?)
|
||
|
||
The following items are checked implicitly by the end of algorithm:
|
||
|
||
4. one of OP0 and OP1 (a_p.2_8) have never been cast
|
||
(because if it was cast to pointer type, its type, that is also
|
||
the type of OP0 and OP1, will be marked as escaped during
|
||
analysis of casting stmt (when check_cast() is called
|
||
from scan_for_refs for this stmt)).
|
||
|
||
5. defs of OP0 and OP1 are not passed into externally visible function
|
||
(because if they are passed then their type, that is also the type of OP0
|
||
and OP1, will be marked and escaped during check_call function called from
|
||
scan_for_refs with call stmt).
|
||
|
||
In total, 1-5 guaranty that it's an access to array by pointer and index.
|
||
|
||
*/
|
||
|
||
static bool
|
||
is_array_access_through_pointer_and_index (tree op0, tree op1)
|
||
{
|
||
tree base, offset, offset_cast_stmt;
|
||
tree before_cast, before_cast_def_stmt;
|
||
cast_t op0_cast, op1_cast;
|
||
|
||
/* Check 1. */
|
||
|
||
/* Init data for walk_use_def_chains function. */
|
||
op0_cast.type = op1_cast.type = 0;
|
||
op0_cast.stmt = op1_cast.stmt = NULL;
|
||
|
||
visited_stmts = pointer_set_create ();
|
||
walk_use_def_chains (op0, is_cast_from_non_pointer,(void *)(&op0_cast), false);
|
||
pointer_set_destroy (visited_stmts);
|
||
|
||
visited_stmts = pointer_set_create ();
|
||
walk_use_def_chains (op1, is_cast_from_non_pointer,(void *)(&op1_cast), false);
|
||
pointer_set_destroy (visited_stmts);
|
||
|
||
if (op0_cast.type == 1 && op1_cast.type == 0)
|
||
{
|
||
base = op1;
|
||
offset = op0;
|
||
offset_cast_stmt = op0_cast.stmt;
|
||
}
|
||
else if (op0_cast.type == 0 && op1_cast.type == 1)
|
||
{
|
||
base = op0;
|
||
offset = op1;
|
||
offset_cast_stmt = op1_cast.stmt;
|
||
}
|
||
else
|
||
return false;
|
||
|
||
/* Check 2.
|
||
offset_cast_stmt is of the form:
|
||
D.1606_7 = (struct str_t *) D.1605_6; */
|
||
|
||
before_cast = SINGLE_SSA_TREE_OPERAND (offset_cast_stmt, SSA_OP_USE);
|
||
if (!before_cast)
|
||
return false;
|
||
|
||
if (SSA_NAME_IS_DEFAULT_DEF(before_cast))
|
||
return false;
|
||
|
||
before_cast_def_stmt = SSA_NAME_DEF_STMT (before_cast);
|
||
if (!before_cast_def_stmt)
|
||
return false;
|
||
|
||
/* before_cast_def_stmt should be of the form:
|
||
D.1605_6 = i.1_5 * 16; */
|
||
|
||
if (TREE_CODE (before_cast_def_stmt) == GIMPLE_MODIFY_STMT)
|
||
{
|
||
tree lhs = GIMPLE_STMT_OPERAND (before_cast_def_stmt,0);
|
||
tree rhs = GIMPLE_STMT_OPERAND (before_cast_def_stmt,1);
|
||
|
||
/* We expect temporary here. */
|
||
if (!is_gimple_reg (lhs))
|
||
return false;
|
||
|
||
if (TREE_CODE (rhs) == MULT_EXPR)
|
||
{
|
||
tree arg0 = TREE_OPERAND (rhs, 0);
|
||
tree arg1 = TREE_OPERAND (rhs, 1);
|
||
tree unit_size =
|
||
TYPE_SIZE_UNIT (TREE_TYPE (TYPE_MAIN_VARIANT (TREE_TYPE (op0))));
|
||
|
||
if (!(CONSTANT_CLASS_P (arg0)
|
||
&& simple_cst_equal (arg0,unit_size))
|
||
&& !(CONSTANT_CLASS_P (arg1)
|
||
&& simple_cst_equal (arg1,unit_size)))
|
||
return false;
|
||
}
|
||
else
|
||
return false;
|
||
}
|
||
else
|
||
return false;
|
||
|
||
/* Check 3.
|
||
check that address of D.1605_6 was not taken.
|
||
FIXME: if D.1605_6 is gimple reg than it cannot be addressable. */
|
||
|
||
return true;
|
||
}
|
||
|
||
/* Register the parameter and return types of function FN. The type
|
||
ESCAPES if the function is visible outside of the compilation
|
||
unit. */
|
||
static void
|
||
check_function_parameter_and_return_types (tree fn, bool escapes)
|
||
{
|
||
tree arg;
|
||
|
||
if (TYPE_ARG_TYPES (TREE_TYPE (fn)))
|
||
{
|
||
for (arg = TYPE_ARG_TYPES (TREE_TYPE (fn));
|
||
arg && TREE_VALUE (arg) != void_type_node;
|
||
arg = TREE_CHAIN (arg))
|
||
{
|
||
tree type = get_canon_type (TREE_VALUE (arg), false, false);
|
||
if (escapes)
|
||
mark_interesting_type (type, EXPOSED_PARAMETER);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* FIXME - According to Geoff Keating, we should never have to
|
||
do this; the front ends should always process the arg list
|
||
from the TYPE_ARG_LIST. However, Geoff is wrong, this code
|
||
does seem to be live. */
|
||
|
||
for (arg = DECL_ARGUMENTS (fn); arg; arg = TREE_CHAIN (arg))
|
||
{
|
||
tree type = get_canon_type (TREE_TYPE (arg), false, false);
|
||
if (escapes)
|
||
mark_interesting_type (type, EXPOSED_PARAMETER);
|
||
}
|
||
}
|
||
if (escapes)
|
||
{
|
||
tree type = get_canon_type (TREE_TYPE (TREE_TYPE (fn)), false, false);
|
||
mark_interesting_type (type, EXPOSED_PARAMETER);
|
||
}
|
||
}
|
||
|
||
/* Return true if the variable T is the right kind of static variable to
|
||
perform compilation unit scope escape analysis. */
|
||
|
||
static inline void
|
||
has_proper_scope_for_analysis (tree t)
|
||
{
|
||
/* If the variable has the "used" attribute, treat it as if it had a
|
||
been touched by the devil. */
|
||
tree type = get_canon_type (TREE_TYPE (t), false, false);
|
||
if (!type) return;
|
||
|
||
if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
|
||
{
|
||
mark_interesting_type (type, FULL_ESCAPE);
|
||
return;
|
||
}
|
||
|
||
/* Do not want to do anything with volatile except mark any
|
||
function that uses one to be not const or pure. */
|
||
if (TREE_THIS_VOLATILE (t))
|
||
return;
|
||
|
||
/* Do not care about a local automatic that is not static. */
|
||
if (!TREE_STATIC (t) && !DECL_EXTERNAL (t))
|
||
return;
|
||
|
||
if (DECL_EXTERNAL (t) || TREE_PUBLIC (t))
|
||
{
|
||
/* If the front end set the variable to be READONLY and
|
||
constant, we can allow this variable in pure or const
|
||
functions but the scope is too large for our analysis to set
|
||
these bits ourselves. */
|
||
|
||
if (TREE_READONLY (t)
|
||
&& DECL_INITIAL (t)
|
||
&& is_gimple_min_invariant (DECL_INITIAL (t)))
|
||
; /* Read of a constant, do not change the function state. */
|
||
else
|
||
{
|
||
/* The type escapes for all public and externs. */
|
||
mark_interesting_type (type, FULL_ESCAPE);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If T is a VAR_DECL for a static that we are interested in, add the
|
||
uid to the bitmap. */
|
||
|
||
static void
|
||
check_operand (tree t)
|
||
{
|
||
if (!t) return;
|
||
|
||
/* This is an assignment from a function, register the types as
|
||
escaping. */
|
||
if (TREE_CODE (t) == FUNCTION_DECL)
|
||
check_function_parameter_and_return_types (t, true);
|
||
|
||
else if (TREE_CODE (t) == VAR_DECL)
|
||
has_proper_scope_for_analysis (t);
|
||
}
|
||
|
||
/* Examine tree T for references. */
|
||
|
||
static void
|
||
check_tree (tree t)
|
||
{
|
||
if ((TREE_CODE (t) == EXC_PTR_EXPR) || (TREE_CODE (t) == FILTER_EXPR))
|
||
return;
|
||
|
||
/* We want to catch here also REALPART_EXPR and IMAGEPART_EXPR,
|
||
but they already included in handled_component_p. */
|
||
while (handled_component_p (t))
|
||
{
|
||
if (TREE_CODE (t) == ARRAY_REF)
|
||
check_operand (TREE_OPERAND (t, 1));
|
||
t = TREE_OPERAND (t, 0);
|
||
}
|
||
|
||
if (INDIRECT_REF_P (t))
|
||
/* || TREE_CODE (t) == MEM_REF) */
|
||
check_tree (TREE_OPERAND (t, 0));
|
||
|
||
if (SSA_VAR_P (t) || (TREE_CODE (t) == FUNCTION_DECL))
|
||
check_operand (t);
|
||
}
|
||
|
||
/* Create an address_of edge FROM_TYPE.TO_TYPE. */
|
||
static void
|
||
mark_interesting_addressof (tree to_type, tree from_type)
|
||
{
|
||
int from_uid;
|
||
int to_uid;
|
||
bitmap type_map;
|
||
splay_tree_node result;
|
||
|
||
from_type = get_canon_type (from_type, false, false);
|
||
to_type = get_canon_type (to_type, false, false);
|
||
|
||
if (!from_type || !to_type)
|
||
return;
|
||
|
||
from_uid = TYPE_UID (from_type);
|
||
to_uid = TYPE_UID (to_type);
|
||
|
||
gcc_assert (ipa_type_escape_star_count_of_interesting_type (from_type) == 0);
|
||
|
||
/* Process the Y into X map pointer. */
|
||
result = splay_tree_lookup (uid_to_addressof_down_map,
|
||
(splay_tree_key) from_uid);
|
||
|
||
if (result)
|
||
type_map = (bitmap) result->value;
|
||
else
|
||
{
|
||
type_map = BITMAP_ALLOC (&ipa_obstack);
|
||
splay_tree_insert (uid_to_addressof_down_map,
|
||
from_uid,
|
||
(splay_tree_value)type_map);
|
||
}
|
||
bitmap_set_bit (type_map, TYPE_UID (to_type));
|
||
|
||
/* Process the X into Y reverse map pointer. */
|
||
result =
|
||
splay_tree_lookup (uid_to_addressof_up_map, (splay_tree_key) to_uid);
|
||
|
||
if (result)
|
||
type_map = (bitmap) result->value;
|
||
else
|
||
{
|
||
type_map = BITMAP_ALLOC (&ipa_obstack);
|
||
splay_tree_insert (uid_to_addressof_up_map,
|
||
to_uid,
|
||
(splay_tree_value)type_map);
|
||
}
|
||
bitmap_set_bit (type_map, TYPE_UID (from_type));
|
||
}
|
||
|
||
/* Scan tree T to see if there are any addresses taken in within T. */
|
||
|
||
static void
|
||
look_for_address_of (tree t)
|
||
{
|
||
if (TREE_CODE (t) == ADDR_EXPR)
|
||
{
|
||
tree x = get_base_var (t);
|
||
tree cref = TREE_OPERAND (t, 0);
|
||
|
||
/* If we have an expression of the form "&a.b.c.d", mark a.b,
|
||
b.c and c.d. as having its address taken. */
|
||
tree fielddecl = NULL_TREE;
|
||
while (cref!= x)
|
||
{
|
||
if (TREE_CODE (cref) == COMPONENT_REF)
|
||
{
|
||
fielddecl = TREE_OPERAND (cref, 1);
|
||
mark_interesting_addressof (TREE_TYPE (fielddecl),
|
||
DECL_FIELD_CONTEXT (fielddecl));
|
||
}
|
||
else if (TREE_CODE (cref) == ARRAY_REF)
|
||
get_canon_type (TREE_TYPE (cref), false, false);
|
||
|
||
cref = TREE_OPERAND (cref, 0);
|
||
}
|
||
|
||
if (TREE_CODE (x) == VAR_DECL)
|
||
has_proper_scope_for_analysis (x);
|
||
}
|
||
}
|
||
|
||
|
||
/* Scan tree T to see if there are any casts within it.
|
||
LHS Is the LHS of the expression involving the cast. */
|
||
|
||
static unsigned int
|
||
look_for_casts (tree lhs ATTRIBUTE_UNUSED, tree t)
|
||
{
|
||
unsigned int cast = 0;
|
||
|
||
|
||
if (is_gimple_cast (t) || TREE_CODE (t) == VIEW_CONVERT_EXPR)
|
||
{
|
||
tree castfromvar = TREE_OPERAND (t, 0);
|
||
cast = cast | check_cast (TREE_TYPE (t), castfromvar);
|
||
}
|
||
else
|
||
while (handled_component_p (t))
|
||
{
|
||
t = TREE_OPERAND (t, 0);
|
||
if (TREE_CODE (t) == VIEW_CONVERT_EXPR)
|
||
{
|
||
/* This may be some part of a component ref.
|
||
IE it may be a.b.VIEW_CONVERT_EXPR<weird_type>(c).d, AFAIK.
|
||
castfromref will give you a.b.c, not a. */
|
||
tree castfromref = TREE_OPERAND (t, 0);
|
||
cast = cast | check_cast (TREE_TYPE (t), castfromref);
|
||
}
|
||
else if (TREE_CODE (t) == COMPONENT_REF)
|
||
get_canon_type (TREE_TYPE (TREE_OPERAND (t, 1)), false, false);
|
||
}
|
||
|
||
if (!cast)
|
||
cast = CT_NO_CAST;
|
||
return cast;
|
||
}
|
||
|
||
/* Check to see if T is a read or address of operation on a static var
|
||
we are interested in analyzing. */
|
||
|
||
static void
|
||
check_rhs_var (tree t)
|
||
{
|
||
look_for_address_of (t);
|
||
check_tree(t);
|
||
}
|
||
|
||
/* Check to see if T is an assignment to a static var we are
|
||
interested in analyzing. */
|
||
|
||
static void
|
||
check_lhs_var (tree t)
|
||
{
|
||
check_tree(t);
|
||
}
|
||
|
||
/* This is a scaled down version of get_asm_expr_operands from
|
||
tree_ssa_operands.c. The version there runs much later and assumes
|
||
that aliasing information is already available. Here we are just
|
||
trying to find if the set of inputs and outputs contain references
|
||
or address of operations to local. FN is the function being
|
||
analyzed and STMT is the actual asm statement. */
|
||
|
||
static void
|
||
get_asm_expr_operands (tree stmt)
|
||
{
|
||
int noutputs = list_length (ASM_OUTPUTS (stmt));
|
||
const char **oconstraints
|
||
= (const char **) alloca ((noutputs) * sizeof (const char *));
|
||
int i;
|
||
tree link;
|
||
const char *constraint;
|
||
bool allows_mem, allows_reg, is_inout;
|
||
|
||
for (i=0, link = ASM_OUTPUTS (stmt); link; ++i, link = TREE_CHAIN (link))
|
||
{
|
||
oconstraints[i] = constraint
|
||
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
|
||
parse_output_constraint (&constraint, i, 0, 0,
|
||
&allows_mem, &allows_reg, &is_inout);
|
||
|
||
check_lhs_var (TREE_VALUE (link));
|
||
}
|
||
|
||
for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
|
||
{
|
||
constraint
|
||
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
|
||
parse_input_constraint (&constraint, 0, 0, noutputs, 0,
|
||
oconstraints, &allows_mem, &allows_reg);
|
||
|
||
check_rhs_var (TREE_VALUE (link));
|
||
}
|
||
|
||
/* There is no code here to check for asm memory clobbers. The
|
||
casual maintainer might think that such code would be necessary,
|
||
but that appears to be wrong. In other parts of the compiler,
|
||
the asm memory clobbers are assumed to only clobber variables
|
||
that are addressable. All types with addressable instances are
|
||
assumed to already escape. So, we are protected here. */
|
||
}
|
||
|
||
/* Check the parameters of a function call to CALL_EXPR to mark the
|
||
types that pass across the function boundary. Also check to see if
|
||
this is either an indirect call, a call outside the compilation
|
||
unit. */
|
||
|
||
static void
|
||
check_call (tree call_expr)
|
||
{
|
||
tree operand;
|
||
tree callee_t = get_callee_fndecl (call_expr);
|
||
struct cgraph_node* callee;
|
||
enum availability avail = AVAIL_NOT_AVAILABLE;
|
||
call_expr_arg_iterator iter;
|
||
|
||
FOR_EACH_CALL_EXPR_ARG (operand, iter, call_expr)
|
||
check_rhs_var (operand);
|
||
|
||
if (callee_t)
|
||
{
|
||
tree arg_type;
|
||
tree last_arg_type = NULL;
|
||
callee = cgraph_node(callee_t);
|
||
avail = cgraph_function_body_availability (callee);
|
||
|
||
/* Check that there are no implicit casts in the passing of
|
||
parameters. */
|
||
if (TYPE_ARG_TYPES (TREE_TYPE (callee_t)))
|
||
{
|
||
for (arg_type = TYPE_ARG_TYPES (TREE_TYPE (callee_t)),
|
||
operand = first_call_expr_arg (call_expr, &iter);
|
||
arg_type && TREE_VALUE (arg_type) != void_type_node;
|
||
arg_type = TREE_CHAIN (arg_type),
|
||
operand = next_call_expr_arg (&iter))
|
||
{
|
||
if (operand)
|
||
{
|
||
last_arg_type = TREE_VALUE(arg_type);
|
||
check_cast (last_arg_type, operand);
|
||
}
|
||
else
|
||
/* The code reaches here for some unfortunate
|
||
builtin functions that do not have a list of
|
||
argument types. */
|
||
break;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* FIXME - According to Geoff Keating, we should never
|
||
have to do this; the front ends should always process
|
||
the arg list from the TYPE_ARG_LIST. */
|
||
for (arg_type = DECL_ARGUMENTS (callee_t),
|
||
operand = first_call_expr_arg (call_expr, &iter);
|
||
arg_type;
|
||
arg_type = TREE_CHAIN (arg_type),
|
||
operand = next_call_expr_arg (&iter))
|
||
{
|
||
if (operand)
|
||
{
|
||
last_arg_type = TREE_TYPE(arg_type);
|
||
check_cast (last_arg_type, operand);
|
||
}
|
||
else
|
||
/* The code reaches here for some unfortunate
|
||
builtin functions that do not have a list of
|
||
argument types. */
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* In the case where we have a var_args function, we need to
|
||
check the remaining parameters against the last argument. */
|
||
arg_type = last_arg_type;
|
||
for (;
|
||
operand != NULL_TREE;
|
||
operand = next_call_expr_arg (&iter))
|
||
{
|
||
if (arg_type)
|
||
check_cast (arg_type, operand);
|
||
else
|
||
{
|
||
/* The code reaches here for some unfortunate
|
||
builtin functions that do not have a list of
|
||
argument types. Most of these functions have
|
||
been marked as having their parameters not
|
||
escape, but for the rest, the type is doomed. */
|
||
tree type = get_canon_type (TREE_TYPE (operand), false, false);
|
||
mark_interesting_type (type, FULL_ESCAPE);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* The callee is either unknown (indirect call) or there is just no
|
||
scannable code for it (external call) . We look to see if there
|
||
are any bits available for the callee (such as by declaration or
|
||
because it is builtin) and process solely on the basis of those
|
||
bits. */
|
||
|
||
if (avail == AVAIL_NOT_AVAILABLE || avail == AVAIL_OVERWRITABLE)
|
||
{
|
||
/* If this is a direct call to an external function, mark all of
|
||
the parameter and return types. */
|
||
FOR_EACH_CALL_EXPR_ARG (operand, iter, call_expr)
|
||
{
|
||
tree type = get_canon_type (TREE_TYPE (operand), false, false);
|
||
mark_interesting_type (type, EXPOSED_PARAMETER);
|
||
}
|
||
|
||
if (callee_t)
|
||
{
|
||
tree type =
|
||
get_canon_type (TREE_TYPE (TREE_TYPE (callee_t)), false, false);
|
||
mark_interesting_type (type, EXPOSED_PARAMETER);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* CODE is the operation on OP0 and OP1. OP0 is the operand that we
|
||
*know* is a pointer type. OP1 may be a pointer type. */
|
||
static bool
|
||
okay_pointer_operation (enum tree_code code, tree op0, tree op1)
|
||
{
|
||
tree op0type = TYPE_MAIN_VARIANT (TREE_TYPE (op0));
|
||
tree op1type = TYPE_MAIN_VARIANT (TREE_TYPE (op1));
|
||
|
||
switch (code)
|
||
{
|
||
case MULT_EXPR:
|
||
/* Multiplication does not change alignment. */
|
||
return true;
|
||
break;
|
||
case MINUS_EXPR:
|
||
case PLUS_EXPR:
|
||
{
|
||
if (POINTER_TYPE_P (op1type)
|
||
&& TREE_CODE (op0) == SSA_NAME
|
||
&& TREE_CODE (op1) == SSA_NAME
|
||
&& is_array_access_through_pointer_and_index (op0, op1))
|
||
return true;
|
||
else
|
||
{
|
||
tree size_of_op0_points_to = TYPE_SIZE_UNIT (TREE_TYPE (op0type));
|
||
|
||
if (CONSTANT_CLASS_P (op1)
|
||
&& size_of_op0_points_to
|
||
&& multiple_of_p (TREE_TYPE (size_of_op0_points_to),
|
||
op1, size_of_op0_points_to))
|
||
return true;
|
||
|
||
if (CONSTANT_CLASS_P (op0)
|
||
&& size_of_op0_points_to
|
||
&& multiple_of_p (TREE_TYPE (size_of_op0_points_to),
|
||
op0, size_of_op0_points_to))
|
||
return true;
|
||
}
|
||
}
|
||
break;
|
||
default:
|
||
return false;
|
||
}
|
||
return false;
|
||
}
|
||
|
||
/* TP is the part of the tree currently under the microscope.
|
||
WALK_SUBTREES is part of the walk_tree api but is unused here.
|
||
DATA is cgraph_node of the function being walked. */
|
||
|
||
/* FIXME: When this is converted to run over SSA form, this code
|
||
should be converted to use the operand scanner. */
|
||
|
||
static tree
|
||
scan_for_refs (tree *tp, int *walk_subtrees, void *data)
|
||
{
|
||
struct cgraph_node *fn = data;
|
||
tree t = *tp;
|
||
|
||
switch (TREE_CODE (t))
|
||
{
|
||
case VAR_DECL:
|
||
if (DECL_INITIAL (t))
|
||
walk_tree (&DECL_INITIAL (t), scan_for_refs, fn, visited_nodes);
|
||
*walk_subtrees = 0;
|
||
break;
|
||
|
||
case GIMPLE_MODIFY_STMT:
|
||
{
|
||
/* First look on the lhs and see what variable is stored to */
|
||
tree lhs = GIMPLE_STMT_OPERAND (t, 0);
|
||
tree rhs = GIMPLE_STMT_OPERAND (t, 1);
|
||
|
||
check_lhs_var (lhs);
|
||
check_cast (TREE_TYPE (lhs), rhs);
|
||
|
||
/* For the purposes of figuring out what the cast affects */
|
||
|
||
/* Next check the operands on the rhs to see if they are ok. */
|
||
switch (TREE_CODE_CLASS (TREE_CODE (rhs)))
|
||
{
|
||
case tcc_binary:
|
||
{
|
||
tree op0 = TREE_OPERAND (rhs, 0);
|
||
tree type0 = get_canon_type (TREE_TYPE (op0), false, false);
|
||
tree op1 = TREE_OPERAND (rhs, 1);
|
||
tree type1 = get_canon_type (TREE_TYPE (op1), false, false);
|
||
|
||
/* If this is pointer arithmetic of any bad sort, then
|
||
we need to mark the types as bad. For binary
|
||
operations, no binary operator we currently support
|
||
is always "safe" in regard to what it would do to
|
||
pointers for purposes of determining which types
|
||
escape, except operations of the size of the type.
|
||
It is possible that min and max under the right set
|
||
of circumstances and if the moon is in the correct
|
||
place could be safe, but it is hard to see how this
|
||
is worth the effort. */
|
||
|
||
if (type0 && POINTER_TYPE_P (type0)
|
||
&& !okay_pointer_operation (TREE_CODE (rhs), op0, op1))
|
||
mark_interesting_type (type0, FULL_ESCAPE);
|
||
if (type1 && POINTER_TYPE_P (type1)
|
||
&& !okay_pointer_operation (TREE_CODE (rhs), op1, op0))
|
||
mark_interesting_type (type1, FULL_ESCAPE);
|
||
|
||
look_for_casts (lhs, op0);
|
||
look_for_casts (lhs, op1);
|
||
check_rhs_var (op0);
|
||
check_rhs_var (op1);
|
||
}
|
||
break;
|
||
case tcc_unary:
|
||
{
|
||
tree op0 = TREE_OPERAND (rhs, 0);
|
||
tree type0 = get_canon_type (TREE_TYPE (op0), false, false);
|
||
/* For unary operations, if the operation is NEGATE or
|
||
ABS on a pointer, this is also considered pointer
|
||
arithmetic and thus, bad for business. */
|
||
if (type0 && (TREE_CODE (op0) == NEGATE_EXPR
|
||
|| TREE_CODE (op0) == ABS_EXPR)
|
||
&& POINTER_TYPE_P (type0))
|
||
{
|
||
mark_interesting_type (type0, FULL_ESCAPE);
|
||
}
|
||
check_rhs_var (op0);
|
||
look_for_casts (lhs, op0);
|
||
look_for_casts (lhs, rhs);
|
||
}
|
||
|
||
break;
|
||
case tcc_reference:
|
||
look_for_casts (lhs, rhs);
|
||
check_rhs_var (rhs);
|
||
break;
|
||
case tcc_declaration:
|
||
check_rhs_var (rhs);
|
||
break;
|
||
case tcc_expression:
|
||
switch (TREE_CODE (rhs))
|
||
{
|
||
case ADDR_EXPR:
|
||
look_for_casts (lhs, TREE_OPERAND (rhs, 0));
|
||
check_rhs_var (rhs);
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
break;
|
||
case tcc_vl_exp:
|
||
switch (TREE_CODE (rhs))
|
||
{
|
||
case CALL_EXPR:
|
||
/* If this is a call to malloc, squirrel away the
|
||
result so we do mark the resulting cast as being
|
||
bad. */
|
||
check_call (rhs);
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
*walk_subtrees = 0;
|
||
}
|
||
break;
|
||
|
||
case ADDR_EXPR:
|
||
/* This case is here to find addresses on rhs of constructors in
|
||
decl_initial of static variables. */
|
||
check_rhs_var (t);
|
||
*walk_subtrees = 0;
|
||
break;
|
||
|
||
case CALL_EXPR:
|
||
check_call (t);
|
||
*walk_subtrees = 0;
|
||
break;
|
||
|
||
case ASM_EXPR:
|
||
get_asm_expr_operands (t);
|
||
*walk_subtrees = 0;
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
return NULL;
|
||
}
|
||
|
||
|
||
/* The init routine for analyzing global static variable usage. See
|
||
comments at top for description. */
|
||
static void
|
||
ipa_init (void)
|
||
{
|
||
bitmap_obstack_initialize (&ipa_obstack);
|
||
global_types_exposed_parameter = BITMAP_ALLOC (&ipa_obstack);
|
||
global_types_full_escape = BITMAP_ALLOC (&ipa_obstack);
|
||
global_types_seen = BITMAP_ALLOC (&ipa_obstack);
|
||
|
||
uid_to_canon_type = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
||
all_canon_types = splay_tree_new (compare_type_brand, 0, 0);
|
||
type_to_canon_type = splay_tree_new (splay_tree_compare_pointers, 0, 0);
|
||
uid_to_subtype_map = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
||
uid_to_addressof_down_map = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
||
uid_to_addressof_up_map = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
||
|
||
/* There are some shared nodes, in particular the initializers on
|
||
static declarations. We do not need to scan them more than once
|
||
since all we would be interested in are the addressof
|
||
operations. */
|
||
visited_nodes = pointer_set_create ();
|
||
initialized = true;
|
||
}
|
||
|
||
/* Check out the rhs of a static or global initialization VNODE to see
|
||
if any of them contain addressof operations. Note that some of
|
||
these variables may not even be referenced in the code in this
|
||
compilation unit but their right hand sides may contain references
|
||
to variables defined within this unit. */
|
||
|
||
static void
|
||
analyze_variable (struct varpool_node *vnode)
|
||
{
|
||
tree global = vnode->decl;
|
||
tree type = get_canon_type (TREE_TYPE (global), false, false);
|
||
|
||
/* If this variable has exposure beyond the compilation unit, add
|
||
its type to the global types. */
|
||
|
||
if (vnode->externally_visible)
|
||
mark_interesting_type (type, FULL_ESCAPE);
|
||
|
||
gcc_assert (TREE_CODE (global) == VAR_DECL);
|
||
|
||
if (DECL_INITIAL (global))
|
||
walk_tree (&DECL_INITIAL (global), scan_for_refs, NULL, visited_nodes);
|
||
}
|
||
|
||
/* This is the main routine for finding the reference patterns for
|
||
global variables within a function FN. */
|
||
|
||
static void
|
||
analyze_function (struct cgraph_node *fn)
|
||
{
|
||
tree decl = fn->decl;
|
||
check_function_parameter_and_return_types (decl,
|
||
fn->local.externally_visible);
|
||
if (dump_file)
|
||
fprintf (dump_file, "\n local analysis of %s", cgraph_node_name (fn));
|
||
|
||
{
|
||
struct function *this_cfun = DECL_STRUCT_FUNCTION (decl);
|
||
basic_block this_block;
|
||
|
||
FOR_EACH_BB_FN (this_block, this_cfun)
|
||
{
|
||
block_stmt_iterator bsi;
|
||
for (bsi = bsi_start (this_block); !bsi_end_p (bsi); bsi_next (&bsi))
|
||
walk_tree (bsi_stmt_ptr (bsi), scan_for_refs,
|
||
fn, visited_nodes);
|
||
}
|
||
}
|
||
|
||
/* There may be const decls with interesting right hand sides. */
|
||
if (DECL_STRUCT_FUNCTION (decl))
|
||
{
|
||
tree step;
|
||
for (step = DECL_STRUCT_FUNCTION (decl)->unexpanded_var_list;
|
||
step;
|
||
step = TREE_CHAIN (step))
|
||
{
|
||
tree var = TREE_VALUE (step);
|
||
if (TREE_CODE (var) == VAR_DECL
|
||
&& DECL_INITIAL (var)
|
||
&& !TREE_STATIC (var))
|
||
walk_tree (&DECL_INITIAL (var), scan_for_refs,
|
||
fn, visited_nodes);
|
||
get_canon_type (TREE_TYPE (var), false, false);
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
|
||
/* Convert a type_UID into a type. */
|
||
static tree
|
||
type_for_uid (int uid)
|
||
{
|
||
splay_tree_node result =
|
||
splay_tree_lookup (uid_to_canon_type, (splay_tree_key) uid);
|
||
|
||
if (result)
|
||
return (tree) result->value;
|
||
else return NULL;
|
||
}
|
||
|
||
/* Return the a bitmap with the subtypes of the type for UID. If it
|
||
does not exist, return either NULL or a new bitmap depending on the
|
||
value of CREATE. */
|
||
|
||
static bitmap
|
||
subtype_map_for_uid (int uid, bool create)
|
||
{
|
||
splay_tree_node result = splay_tree_lookup (uid_to_subtype_map,
|
||
(splay_tree_key) uid);
|
||
|
||
if (result)
|
||
return (bitmap) result->value;
|
||
else if (create)
|
||
{
|
||
bitmap subtype_map = BITMAP_ALLOC (&ipa_obstack);
|
||
splay_tree_insert (uid_to_subtype_map,
|
||
uid,
|
||
(splay_tree_value)subtype_map);
|
||
return subtype_map;
|
||
}
|
||
else return NULL;
|
||
}
|
||
|
||
/* Mark all of the supertypes and field types of TYPE as being seen.
|
||
Also accumulate the subtypes for each type so that
|
||
close_types_full_escape can mark a subtype as escaping if the
|
||
supertype escapes. */
|
||
|
||
static void
|
||
close_type_seen (tree type)
|
||
{
|
||
tree field;
|
||
int i, uid;
|
||
tree binfo, base_binfo;
|
||
|
||
/* See thru all pointer tos and array ofs. */
|
||
type = get_canon_type (type, true, true);
|
||
if (!type)
|
||
return;
|
||
|
||
uid = TYPE_UID (type);
|
||
|
||
if (bitmap_bit_p (been_there_done_that, uid))
|
||
return;
|
||
bitmap_set_bit (been_there_done_that, uid);
|
||
|
||
/* If we are doing a language with a type hierarchy, mark all of
|
||
the superclasses. */
|
||
if (TYPE_BINFO (type))
|
||
for (binfo = TYPE_BINFO (type), i = 0;
|
||
BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
|
||
{
|
||
tree binfo_type = BINFO_TYPE (base_binfo);
|
||
bitmap subtype_map = subtype_map_for_uid
|
||
(TYPE_UID (TYPE_MAIN_VARIANT (binfo_type)), true);
|
||
bitmap_set_bit (subtype_map, uid);
|
||
close_type_seen (get_canon_type (binfo_type, true, true));
|
||
}
|
||
|
||
/* If the field is a struct or union type, mark all of the
|
||
subfields. */
|
||
for (field = TYPE_FIELDS (type);
|
||
field;
|
||
field = TREE_CHAIN (field))
|
||
{
|
||
tree field_type;
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
field_type = TREE_TYPE (field);
|
||
if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0)
|
||
close_type_seen (get_canon_type (field_type, true, true));
|
||
}
|
||
}
|
||
|
||
/* Take a TYPE that has been passed by value to an external function
|
||
and mark all of the fields that have pointer types as escaping. For
|
||
any of the non pointer types that are structures or unions,
|
||
recurse. TYPE is never a pointer type. */
|
||
|
||
static void
|
||
close_type_exposed_parameter (tree type)
|
||
{
|
||
tree field;
|
||
int uid;
|
||
|
||
type = get_canon_type (type, false, false);
|
||
if (!type)
|
||
return;
|
||
uid = TYPE_UID (type);
|
||
gcc_assert (!POINTER_TYPE_P (type));
|
||
|
||
if (bitmap_bit_p (been_there_done_that, uid))
|
||
return;
|
||
bitmap_set_bit (been_there_done_that, uid);
|
||
|
||
/* If the field is a struct or union type, mark all of the
|
||
subfields. */
|
||
for (field = TYPE_FIELDS (type);
|
||
field;
|
||
field = TREE_CHAIN (field))
|
||
{
|
||
tree field_type;
|
||
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
field_type = get_canon_type (TREE_TYPE (field), false, false);
|
||
mark_interesting_type (field_type, EXPOSED_PARAMETER);
|
||
|
||
/* Only recurse for non pointer types of structures and unions. */
|
||
if (ipa_type_escape_star_count_of_interesting_type (field_type) == 0)
|
||
close_type_exposed_parameter (field_type);
|
||
}
|
||
}
|
||
|
||
/* The next function handles the case where a type fully escapes.
|
||
This means that not only does the type itself escape,
|
||
|
||
a) the type of every field recursively escapes
|
||
b) the type of every subtype escapes as well as the super as well
|
||
as all of the pointer to types for each field.
|
||
|
||
Note that pointer to types are not marked as escaping. If the
|
||
pointed to type escapes, the pointer to type also escapes.
|
||
|
||
Take a TYPE that has had the address taken for an instance of it
|
||
and mark all of the types for its fields as having their addresses
|
||
taken. */
|
||
|
||
static void
|
||
close_type_full_escape (tree type)
|
||
{
|
||
tree field;
|
||
unsigned int i;
|
||
int uid;
|
||
tree binfo, base_binfo;
|
||
bitmap_iterator bi;
|
||
bitmap subtype_map;
|
||
splay_tree_node address_result;
|
||
|
||
/* Strip off any pointer or array types. */
|
||
type = get_canon_type (type, true, true);
|
||
if (!type)
|
||
return;
|
||
uid = TYPE_UID (type);
|
||
|
||
if (bitmap_bit_p (been_there_done_that, uid))
|
||
return;
|
||
bitmap_set_bit (been_there_done_that, uid);
|
||
|
||
subtype_map = subtype_map_for_uid (uid, false);
|
||
|
||
/* If we are doing a language with a type hierarchy, mark all of
|
||
the superclasses. */
|
||
if (TYPE_BINFO (type))
|
||
for (binfo = TYPE_BINFO (type), i = 0;
|
||
BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
|
||
{
|
||
tree binfotype = BINFO_TYPE (base_binfo);
|
||
binfotype = mark_type (binfotype, FULL_ESCAPE);
|
||
close_type_full_escape (binfotype);
|
||
}
|
||
|
||
/* Mark as escaped any types that have been down casted to
|
||
this type. */
|
||
if (subtype_map)
|
||
EXECUTE_IF_SET_IN_BITMAP (subtype_map, 0, i, bi)
|
||
{
|
||
tree subtype = type_for_uid (i);
|
||
subtype = mark_type (subtype, FULL_ESCAPE);
|
||
close_type_full_escape (subtype);
|
||
}
|
||
|
||
/* If the field is a struct or union type, mark all of the
|
||
subfields. */
|
||
for (field = TYPE_FIELDS (type);
|
||
field;
|
||
field = TREE_CHAIN (field))
|
||
{
|
||
tree field_type;
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
field_type = TREE_TYPE (field);
|
||
if (ipa_type_escape_star_count_of_interesting_or_array_type (field_type) >= 0)
|
||
{
|
||
field_type = mark_type (field_type, FULL_ESCAPE);
|
||
close_type_full_escape (field_type);
|
||
}
|
||
}
|
||
|
||
/* For all of the types A that contain this type B and were part of
|
||
an expression like "&...A.B...", mark the A's as escaping. */
|
||
address_result = splay_tree_lookup (uid_to_addressof_up_map,
|
||
(splay_tree_key) uid);
|
||
if (address_result)
|
||
{
|
||
bitmap containing_classes = (bitmap) address_result->value;
|
||
EXECUTE_IF_SET_IN_BITMAP (containing_classes, 0, i, bi)
|
||
{
|
||
close_type_full_escape (type_for_uid (i));
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Transitively close the addressof bitmap for the type with UID.
|
||
This means that if we had a.b and b.c, a would have both b and c in
|
||
its maps. */
|
||
|
||
static bitmap
|
||
close_addressof_down (int uid)
|
||
{
|
||
bitmap_iterator bi;
|
||
splay_tree_node result =
|
||
splay_tree_lookup (uid_to_addressof_down_map, (splay_tree_key) uid);
|
||
bitmap map = NULL;
|
||
bitmap new_map;
|
||
unsigned int i;
|
||
|
||
if (result)
|
||
map = (bitmap) result->value;
|
||
else
|
||
return NULL;
|
||
|
||
if (bitmap_bit_p (been_there_done_that, uid))
|
||
return map;
|
||
bitmap_set_bit (been_there_done_that, uid);
|
||
|
||
/* If the type escapes, get rid of the addressof map, it will not be
|
||
needed. */
|
||
if (bitmap_bit_p (global_types_full_escape, uid))
|
||
{
|
||
BITMAP_FREE (map);
|
||
splay_tree_remove (uid_to_addressof_down_map, (splay_tree_key) uid);
|
||
return NULL;
|
||
}
|
||
|
||
/* The new_map will have all of the bits for the enclosed fields and
|
||
will have the unique id version of the old map. */
|
||
new_map = BITMAP_ALLOC (&ipa_obstack);
|
||
|
||
EXECUTE_IF_SET_IN_BITMAP (map, 0, i, bi)
|
||
{
|
||
bitmap submap = close_addressof_down (i);
|
||
bitmap_set_bit (new_map, i);
|
||
if (submap)
|
||
bitmap_ior_into (new_map, submap);
|
||
}
|
||
result->value = (splay_tree_value) new_map;
|
||
|
||
BITMAP_FREE (map);
|
||
return new_map;
|
||
}
|
||
|
||
|
||
/* The main entry point for type escape analysis. */
|
||
|
||
static unsigned int
|
||
type_escape_execute (void)
|
||
{
|
||
struct cgraph_node *node;
|
||
struct varpool_node *vnode;
|
||
unsigned int i;
|
||
bitmap_iterator bi;
|
||
splay_tree_node result;
|
||
|
||
ipa_init ();
|
||
|
||
/* Process all of the variables first. */
|
||
FOR_EACH_STATIC_VARIABLE (vnode)
|
||
analyze_variable (vnode);
|
||
|
||
/* Process all of the functions. next
|
||
|
||
We do not want to process any of the clones so we check that this
|
||
is a master clone. However, we do need to process any
|
||
AVAIL_OVERWRITABLE functions (these are never clones) because
|
||
they may cause a type variable to escape.
|
||
*/
|
||
for (node = cgraph_nodes; node; node = node->next)
|
||
if (node->analyzed
|
||
&& (cgraph_is_master_clone (node)
|
||
|| (cgraph_function_body_availability (node) == AVAIL_OVERWRITABLE)))
|
||
analyze_function (node);
|
||
|
||
|
||
pointer_set_destroy (visited_nodes);
|
||
visited_nodes = NULL;
|
||
|
||
/* Do all of the closures to discover which types escape the
|
||
compilation unit. */
|
||
|
||
been_there_done_that = BITMAP_ALLOC (&ipa_obstack);
|
||
bitmap_tmp = BITMAP_ALLOC (&ipa_obstack);
|
||
|
||
/* Examine the types that we have directly seen in scanning the code
|
||
and add to that any contained types or superclasses. */
|
||
|
||
bitmap_copy (bitmap_tmp, global_types_seen);
|
||
EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi)
|
||
{
|
||
tree type = type_for_uid (i);
|
||
/* Only look at records and unions and pointer tos. */
|
||
if (ipa_type_escape_star_count_of_interesting_or_array_type (type) >= 0)
|
||
close_type_seen (type);
|
||
}
|
||
bitmap_clear (been_there_done_that);
|
||
|
||
/* Examine all of the types passed by value and mark any enclosed
|
||
pointer types as escaping. */
|
||
bitmap_copy (bitmap_tmp, global_types_exposed_parameter);
|
||
EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi)
|
||
{
|
||
close_type_exposed_parameter (type_for_uid (i));
|
||
}
|
||
bitmap_clear (been_there_done_that);
|
||
|
||
/* Close the types for escape. If something escapes, then any
|
||
enclosed types escape as well as any subtypes. */
|
||
bitmap_copy (bitmap_tmp, global_types_full_escape);
|
||
EXECUTE_IF_SET_IN_BITMAP (bitmap_tmp, 0, i, bi)
|
||
{
|
||
close_type_full_escape (type_for_uid (i));
|
||
}
|
||
bitmap_clear (been_there_done_that);
|
||
|
||
/* Before this pass, the uid_to_addressof_down_map for type X
|
||
contained an entry for Y if there had been an operation of the
|
||
form &X.Y. This step adds all of the fields contained within Y
|
||
(recursively) to X's map. */
|
||
|
||
result = splay_tree_min (uid_to_addressof_down_map);
|
||
while (result)
|
||
{
|
||
int uid = result->key;
|
||
/* Close the addressof map, i.e. copy all of the transitive
|
||
substructures up to this level. */
|
||
close_addressof_down (uid);
|
||
result = splay_tree_successor (uid_to_addressof_down_map, uid);
|
||
}
|
||
|
||
/* Do not need the array types and pointer types in the persistent
|
||
data structures. */
|
||
result = splay_tree_min (all_canon_types);
|
||
while (result)
|
||
{
|
||
tree type = (tree) result->value;
|
||
tree key = (tree) result->key;
|
||
if (POINTER_TYPE_P (type)
|
||
|| TREE_CODE (type) == ARRAY_TYPE)
|
||
{
|
||
splay_tree_remove (all_canon_types, (splay_tree_key) result->key);
|
||
splay_tree_remove (type_to_canon_type, (splay_tree_key) type);
|
||
splay_tree_remove (uid_to_canon_type, (splay_tree_key) TYPE_UID (type));
|
||
bitmap_clear_bit (global_types_seen, TYPE_UID (type));
|
||
}
|
||
result = splay_tree_successor (all_canon_types, (splay_tree_key) key);
|
||
}
|
||
|
||
if (dump_file)
|
||
{
|
||
EXECUTE_IF_SET_IN_BITMAP (global_types_seen, 0, i, bi)
|
||
{
|
||
/* The pointer types are in the global_types_full_escape
|
||
bitmap but not in the backwards map. They also contain
|
||
no useful information since they are not marked. */
|
||
tree type = type_for_uid (i);
|
||
fprintf(dump_file, "type %d ", i);
|
||
print_generic_expr (dump_file, type, 0);
|
||
if (bitmap_bit_p (global_types_full_escape, i))
|
||
fprintf(dump_file, " escaped\n");
|
||
else
|
||
fprintf(dump_file, " contained\n");
|
||
}
|
||
}
|
||
|
||
/* Get rid of uid_to_addressof_up_map and its bitmaps. */
|
||
result = splay_tree_min (uid_to_addressof_up_map);
|
||
while (result)
|
||
{
|
||
int uid = (int)result->key;
|
||
bitmap bm = (bitmap)result->value;
|
||
|
||
BITMAP_FREE (bm);
|
||
splay_tree_remove (uid_to_addressof_up_map, (splay_tree_key) uid);
|
||
result = splay_tree_successor (uid_to_addressof_up_map, uid);
|
||
}
|
||
|
||
/* Get rid of the subtype map. */
|
||
result = splay_tree_min (uid_to_subtype_map);
|
||
while (result)
|
||
{
|
||
bitmap b = (bitmap)result->value;
|
||
BITMAP_FREE(b);
|
||
splay_tree_remove (uid_to_subtype_map, result->key);
|
||
result = splay_tree_min (uid_to_subtype_map);
|
||
}
|
||
splay_tree_delete (uid_to_subtype_map);
|
||
uid_to_subtype_map = NULL;
|
||
|
||
BITMAP_FREE (global_types_exposed_parameter);
|
||
BITMAP_FREE (been_there_done_that);
|
||
BITMAP_FREE (bitmap_tmp);
|
||
return 0;
|
||
}
|
||
|
||
static bool
|
||
gate_type_escape_vars (void)
|
||
{
|
||
return (flag_unit_at_a_time != 0 && flag_ipa_type_escape
|
||
/* Don't bother doing anything if the program has errors. */
|
||
&& !(errorcount || sorrycount));
|
||
}
|
||
|
||
struct tree_opt_pass pass_ipa_type_escape =
|
||
{
|
||
"type-escape-var", /* name */
|
||
gate_type_escape_vars, /* gate */
|
||
type_escape_execute, /* execute */
|
||
NULL, /* sub */
|
||
NULL, /* next */
|
||
0, /* static_pass_number */
|
||
TV_IPA_TYPE_ESCAPE, /* tv_id */
|
||
0, /* properties_required */
|
||
0, /* properties_provided */
|
||
0, /* properties_destroyed */
|
||
0, /* todo_flags_start */
|
||
0, /* todo_flags_finish */
|
||
0 /* letter */
|
||
};
|
||
|