diff options
Diffstat (limited to 'gcc/ipa-type-escape.c')
| -rw-r--r-- | gcc/ipa-type-escape.c | 2126 |
1 files changed, 0 insertions, 2126 deletions
diff --git a/gcc/ipa-type-escape.c b/gcc/ipa-type-escape.c deleted file mode 100644 index 1ecf68e..0000000 --- a/gcc/ipa-type-escape.c +++ /dev/null @@ -1,2126 +0,0 @@ -/* Escape analysis for types. - Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010 - Free Software Foundation, Inc. - Contributed by Kenneth Zadeck <zadeck@naturalbridge.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 3, 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 COPYING3. If not see -<http://www.gnu.org/licenses/>. */ - -/* This pass determines which types in the program contain only - instances that are completely encapsulated by the compilation unit. - Those types that are encapsulated must also pass the further - requirement that there be no bad operations on any instances of - those types. - - A great deal of freedom in compilation is allowed for the instances - of those types that pass these conditions. -*/ - -/* The code in this module is called by the ipa pass manager. It - should be one of the later passes since its information is used by - the rest of the compilation. */ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "tm.h" -#include "tree.h" -#include "tree-flow.h" -#include "tree-inline.h" -#include "tree-pass.h" -#include "langhooks.h" -#include "pointer-set.h" -#include "splay-tree.h" -#include "ggc.h" -#include "ipa-utils.h" -#include "ipa-type-escape.h" -#include "gimple.h" -#include "cgraph.h" -#include "output.h" -#include "flags.h" -#include "timevar.h" -#include "diagnostic.h" -#include "tree-pretty-print.h" -#include "langhooks.h" - -/* Some of the aliasing is called very early, before this phase is - called. To assure that this is not a problem, we keep track of if - this phase has been run. */ -static bool initialized = false; - -/* Scratch bitmap for avoiding work. */ -static bitmap been_there_done_that; -static bitmap bitmap_tmp; - -/* There are two levels of escape that types can undergo. - - EXPOSED_PARAMETER - some instance of the variable is - passed by value into an externally visible function or some - instance of the variable is passed out of an externally visible - function as a return value. In this case any of the fields of the - variable that are pointer types end up having their types marked as - FULL_ESCAPE. - - FULL_ESCAPE - when bad things happen to good types. One of the - following things happens to the type: (a) either an instance of the - variable has its address passed to an externally visible function, - (b) the address is taken and some bad cast happens to the address - or (c) explicit arithmetic is done to the address. -*/ - -enum escape_t -{ - EXPOSED_PARAMETER, - FULL_ESCAPE -}; - -/* The following two bit vectors global_types_* correspond to - previous cases above. During the analysis phase, a bit is set in - one of these vectors if an operation of the offending class is - discovered to happen on the associated type. */ - -static bitmap global_types_exposed_parameter; -static bitmap global_types_full_escape; - -/* All of the types seen in this compilation unit. */ -static bitmap global_types_seen; -/* Reverse map to take a canon uid and map it to a canon type. Uid's - are never manipulated unless they are associated with a canon - type. */ -static splay_tree uid_to_canon_type; - -/* Internal structure of type mapping code. This maps a canon type - name to its canon type. */ -static splay_tree all_canon_types; - -/* Map from type clones to the single canon type. */ -static splay_tree type_to_canon_type; - -/* A splay tree of bitmaps. An element X in the splay tree has a bit - set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (Y)) if there was - an operation in the program of the form "&X.Y". */ -static splay_tree uid_to_addressof_down_map; - -/* A splay tree of bitmaps. An element Y in the splay tree has a bit - set in its bitmap at TYPE_UID (TYPE_MAIN_VARIANT (X)) if there was - an operation in the program of the form "&X.Y". */ -static splay_tree uid_to_addressof_up_map; - -/* Tree to hold the subtype maps used to mark subtypes of escaped - types. */ -static splay_tree uid_to_subtype_map; - -/* Records tree nodes seen in cgraph_create_edges. Simply using - walk_tree_without_duplicates doesn't guarantee each node is visited - once because it gets a new htab upon each recursive call from - scan_for_refs. */ -static struct pointer_set_t *visited_nodes; - -/* Visited stmts by walk_use_def_chains function because it's called - recursively. */ -static struct pointer_set_t *visited_stmts; - -static bitmap_obstack ipa_obstack; - -/* Static functions from this file that are used - before being defined. */ -static unsigned int look_for_casts (tree); -static bool is_cast_from_non_pointer (tree, gimple, void *); - -/* Get the name of TYPE or return the string "<UNNAMED>". */ -static const char* -get_name_of_type (tree type) -{ - tree name = TYPE_NAME (type); - - if (!name) - /* Unnamed type, do what you like here. */ - return "<UNNAMED>"; - - /* It will be a TYPE_DECL in the case of a typedef, otherwise, an - identifier_node */ - if (TREE_CODE (name) == TYPE_DECL) - { - /* Each DECL has a DECL_NAME field which contains an - IDENTIFIER_NODE. (Some decls, most often labels, may have - zero as the DECL_NAME). */ - if (DECL_NAME (name)) - return IDENTIFIER_POINTER (DECL_NAME (name)); - else - /* Unnamed type, do what you like here. */ - return "<UNNAMED>"; - } - else if (TREE_CODE (name) == IDENTIFIER_NODE) - return IDENTIFIER_POINTER (name); - else - return "<UNNAMED>"; -} - -struct type_brand_s -{ - const char* name; - int seq; -}; - -/* Splay tree comparison function on type_brand_s structures. */ - -static int -compare_type_brand (splay_tree_key sk1, splay_tree_key sk2) -{ - struct type_brand_s * k1 = (struct type_brand_s *) sk1; - struct type_brand_s * k2 = (struct type_brand_s *) sk2; - - int value = strcmp(k1->name, k2->name); - if (value == 0) - return k2->seq - k1->seq; - else - return value; -} - -/* All of the "unique_type" code is a hack to get around the sleazy - implementation used to compile more than file. Currently gcc does - not get rid of multiple instances of the same type that have been - collected from different compilation units. */ -/* This is a trivial algorithm for removing duplicate types. This - would not work for any language that used structural equivalence as - the basis of its type system. */ -/* Return TYPE if no type compatible with TYPE has been seen so far, - otherwise return a type compatible with TYPE that has already been - processed. */ - -static tree -discover_unique_type (tree type) -{ - struct type_brand_s * brand = XNEW (struct type_brand_s); - int i = 0; - splay_tree_node result; - - brand->name = get_name_of_type (type); - - while (1) - { - brand->seq = i++; - result = splay_tree_lookup (all_canon_types, (splay_tree_key) brand); - - if (result) - { - /* Create an alias since this is just the same as - other_type. */ - tree other_type = (tree) result->value; - if (types_compatible_p (type, other_type)) - { - free (brand); - /* Insert this new type as an alias for other_type. */ - splay_tree_insert (type_to_canon_type, - (splay_tree_key) type, - (splay_tree_value) other_type); - return other_type; - } - /* Not compatible, look for next instance with same name. */ - } - else - { - /* No more instances, create new one since this is the first - time we saw this type. */ - brand->seq = i++; - /* Insert the new brand. */ - splay_tree_insert (all_canon_types, - (splay_tree_key) brand, - (splay_tree_value) type); - - /* Insert this new type as an alias for itself. */ - splay_tree_insert (type_to_canon_type, - (splay_tree_key) type, - (splay_tree_value) type); - - /* Insert the uid for reverse lookup; */ - splay_tree_insert (uid_to_canon_type, - (splay_tree_key) TYPE_UID (type), - (splay_tree_value) type); - - bitmap_set_bit (global_types_seen, TYPE_UID (type)); - return type; - } - } -} - -/* Return true if TYPE is one of the type classes that we are willing - to analyze. This skips the goofy types like arrays of pointers to - methods. */ -static bool -type_to_consider (tree type) -{ - /* Strip the *'s off. */ - type = TYPE_MAIN_VARIANT (type); - while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) - type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); - - switch (TREE_CODE (type)) - { - case BOOLEAN_TYPE: - case COMPLEX_TYPE: - case ENUMERAL_TYPE: - case INTEGER_TYPE: - case QUAL_UNION_TYPE: - case REAL_TYPE: - case FIXED_POINT_TYPE: - case RECORD_TYPE: - case UNION_TYPE: - case VECTOR_TYPE: - case VOID_TYPE: - return true; - - default: - return false; - } -} - -/* Get the canon type of TYPE. If SEE_THRU_PTRS is true, remove all - the POINTER_TOs and if SEE_THRU_ARRAYS is true, remove all of the - ARRAY_OFs and POINTER_TOs. */ - -static tree -get_canon_type (tree type, bool see_thru_ptrs, bool see_thru_arrays) -{ - splay_tree_node result; - /* Strip the *'s off. */ - if (!type || !type_to_consider (type)) - return NULL; - - type = TYPE_MAIN_VARIANT (type); - if (see_thru_arrays) - while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) - type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); - - else if (see_thru_ptrs) - while (POINTER_TYPE_P (type)) - type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); - - result = splay_tree_lookup (type_to_canon_type, (splay_tree_key) type); - - if (result == NULL) - return discover_unique_type (type); - else return (tree) result->value; -} - -/* Same as GET_CANON_TYPE, except return the TYPE_ID rather than the - TYPE. */ - -static int -get_canon_type_uid (tree type, bool see_thru_ptrs, bool see_thru_arrays) -{ - type = get_canon_type (type, see_thru_ptrs, see_thru_arrays); - if (type) - return TYPE_UID(type); - else return 0; -} - -/* Return 0 if TYPE is a record or union type. Return a positive - number if TYPE is a pointer to a record or union. The number is - the number of pointer types stripped to get to the record or union - type. Return -1 if TYPE is none of the above. */ - -int -ipa_type_escape_star_count_of_interesting_type (tree type) -{ - int count = 0; - /* Strip the *'s off. */ - if (!type) - return -1; - type = TYPE_MAIN_VARIANT (type); - while (POINTER_TYPE_P (type)) - { - type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); - count++; - } - - /* We are interested in records, and unions only. */ - if (TREE_CODE (type) == RECORD_TYPE - || TREE_CODE (type) == QUAL_UNION_TYPE - || TREE_CODE (type) == UNION_TYPE) - return count; - else - return -1; -} - - -/* Return 0 if TYPE is a record or union type. Return a positive - number if TYPE is a pointer to a record or union. The number is - the number of pointer types stripped to get to the record or union - type. Return -1 if TYPE is none of the above. */ - -int -ipa_type_escape_star_count_of_interesting_or_array_type (tree type) -{ - int count = 0; - /* Strip the *'s off. */ - if (!type) - return -1; - type = TYPE_MAIN_VARIANT (type); - while (POINTER_TYPE_P (type) || TREE_CODE (type) == ARRAY_TYPE) - { - type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); - count++; - } - - /* We are interested in records, and unions only. */ - if (TREE_CODE (type) == RECORD_TYPE - || TREE_CODE (type) == QUAL_UNION_TYPE - || TREE_CODE (type) == UNION_TYPE) - return count; - else - return -1; -} - - -/* Return true if the record, or union TYPE passed in escapes this - compilation unit. Note that all of the pointer-to's are removed - before testing since these may not be correct. */ - -bool -ipa_type_escape_type_contained_p (tree type) -{ - if (!initialized) - return false; - return !bitmap_bit_p (global_types_full_escape, - get_canon_type_uid (type, true, false)); -} - -/* Return true if a modification to a field of type FIELD_TYPE cannot - clobber a record of RECORD_TYPE. */ - -bool -ipa_type_escape_field_does_not_clobber_p (tree record_type, tree field_type) -{ - splay_tree_node result; - int uid; - - if (!initialized) - return false; - - /* Strip off all of the pointer tos on the record type. Strip the - same number of pointer tos from the field type. If the field - type has fewer, it could not have been aliased. */ - record_type = TYPE_MAIN_VARIANT (record_type); - field_type = TYPE_MAIN_VARIANT (field_type); - while (POINTER_TYPE_P (record_type)) - { - record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type)); - if (POINTER_TYPE_P (field_type)) - field_type = TYPE_MAIN_VARIANT (TREE_TYPE (field_type)); - else - /* However, if field_type is a union, this quick test is not - correct since one of the variants of the union may be a - pointer to type and we cannot see across that here. So we - just strip the remaining pointer tos off the record type - and fall thru to the more precise code. */ - if (TREE_CODE (field_type) == QUAL_UNION_TYPE - || TREE_CODE (field_type) == UNION_TYPE) - { - while (POINTER_TYPE_P (record_type)) - record_type = TYPE_MAIN_VARIANT (TREE_TYPE (record_type)); - break; - } - else - return true; - } - - record_type = get_canon_type (record_type, true, true); - /* The record type must be contained. The field type may - escape. */ - if (!ipa_type_escape_type_contained_p (record_type)) - 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; - 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. */ - -static tree -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: - map = global_types_exposed_parameter; - break; - case FULL_ESCAPE: - map = global_types_full_escape; - break; - } - - uid = TYPE_UID (type); - if (!bitmap_set_bit (map, uid)) - return type; - else 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 nonzero if VAR is result of call - to malloc function. */ - -static bool -is_malloc_result (tree var) -{ - gimple def_stmt; - - if (!var) - return false; - - if (SSA_NAME_IS_DEFAULT_DEF (var)) - return false; - - def_stmt = SSA_NAME_DEF_STMT (var); - - if (!is_gimple_call (def_stmt)) - return false; - - if (var != gimple_call_lhs (def_stmt)) - return false; - - return ((gimple_call_flags (def_stmt) & 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; -} - - -/* Scan assignment statement S to see if there are any casts within it. */ - -static unsigned int -look_for_casts_stmt (gimple s) -{ - unsigned int cast = 0; - - gcc_assert (is_gimple_assign (s)); - - if (gimple_assign_cast_p (s)) - { - tree castfromvar = gimple_assign_rhs1 (s); - cast |= check_cast (TREE_TYPE (gimple_assign_lhs (s)), castfromvar); - } - else - { - size_t i; - for (i = 0; i < gimple_num_ops (s); i++) - cast |= look_for_casts (gimple_op (s, i)); - } - - if (!cast) - cast = CT_NO_CAST; - - return cast; -} - - -typedef struct cast -{ - int type; - gimple stmt; -} cast_t; - -/* 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, gimple def_stmt, void *data) -{ - if (!def_stmt || !var) - return false; - - if (gimple_code (def_stmt) == GIMPLE_PHI) - return false; - - if (SSA_NAME_IS_DEFAULT_DEF (var)) - return false; - - if (is_gimple_assign (def_stmt)) - { - use_operand_p use_p; - ssa_op_iter iter; - unsigned int cast = look_for_casts_stmt (def_stmt); - - /* 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) - break; - } - } - /* 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) - break; - } - } - /* The cast is harmful. */ - else - ((cast_t *)data)->type = -1; - } - - 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. - -*/ - -bool -is_array_access_through_pointer_and_index (enum tree_code code, tree op0, - tree op1, tree *base, tree *offset, - gimple *offset_cast_stmt) -{ - tree before_cast; - gimple before_cast_def_stmt; - cast_t op0_cast, op1_cast; - - *base = NULL; - *offset = NULL; - *offset_cast_stmt = NULL; - - /* Check 1. */ - if (code == POINTER_PLUS_EXPR) - { - tree op0type = TYPE_MAIN_VARIANT (TREE_TYPE (op0)); - tree op1type = TYPE_MAIN_VARIANT (TREE_TYPE (op1)); - - /* One of op0 and op1 is of pointer type and the other is numerical. */ - if (POINTER_TYPE_P (op0type) && NUMERICAL_TYPE_CHECK (op1type)) - { - *base = op0; - *offset = op1; - } - else if (POINTER_TYPE_P (op1type) && NUMERICAL_TYPE_CHECK (op0type)) - { - *base = op1; - *offset = op0; - } - else - return false; - } - else - { - /* 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; */ - - if (*offset_cast_stmt) - { - 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; - } - else - before_cast_def_stmt = SSA_NAME_DEF_STMT (*offset); - - /* before_cast_def_stmt should be of the form: - D.1605_6 = i.1_5 * 16; */ - - if (is_gimple_assign (before_cast_def_stmt)) - { - /* We expect temporary here. */ - if (!is_gimple_reg (gimple_assign_lhs (before_cast_def_stmt))) - return false; - - if (gimple_assign_rhs_code (before_cast_def_stmt) == MULT_EXPR) - { - tree arg0 = gimple_assign_rhs1 (before_cast_def_stmt); - tree arg1 = gimple_assign_rhs2 (before_cast_def_stmt); - 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 (prototype_p (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 = DECL_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 (DECL_PRESERVE_P (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) -{ - /* 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); - if (DECL_P (t) && DECL_INITIAL (t)) - check_tree (DECL_INITIAL (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. */ - -static unsigned int -look_for_casts (tree t) -{ - unsigned int cast = 0; - - if (CONVERT_EXPR_P (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 -check_asm (gimple stmt) -{ - size_t i; - - for (i = 0; i < gimple_asm_noutputs (stmt); i++) - check_lhs_var (gimple_asm_output_op (stmt, i)); - - for (i = 0; i < gimple_asm_ninputs (stmt); i++) - check_rhs_var (gimple_asm_input_op (stmt, i)); - - /* 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 function call to CALL 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 (gimple call) -{ - tree callee_t = gimple_call_fndecl (call); - struct cgraph_node* callee; - enum availability avail = AVAIL_NOT_AVAILABLE; - size_t i; - - for (i = 0; i < gimple_call_num_args (call); i++) - check_rhs_var (gimple_call_arg (call, i)); - - 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 (prototype_p (TREE_TYPE (callee_t))) - { - for (arg_type = TYPE_ARG_TYPES (TREE_TYPE (callee_t)), i = 0; - arg_type && TREE_VALUE (arg_type) != void_type_node - && i < gimple_call_num_args (call); - arg_type = TREE_CHAIN (arg_type), i++) - { - tree operand = gimple_call_arg (call, i); - 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), i = 0; - arg_type && i < gimple_call_num_args (call); - arg_type = TREE_CHAIN (arg_type), i++) - { - tree operand = gimple_call_arg (call, i); - 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 ( ; i < gimple_call_num_args (call); i++) - { - tree operand = gimple_call_arg (call, i); - 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 (i = 0; i < gimple_call_num_args (call); i++) - { - tree operand = gimple_call_arg (call, i); - 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)); - - switch (code) - { - case MULT_EXPR: - /* Multiplication does not change alignment. */ - return true; - break; - case MINUS_EXPR: - case PLUS_EXPR: - case POINTER_PLUS_EXPR: - { - tree base, offset; - gimple offset_cast_stmt; - - if (POINTER_TYPE_P (op0type) - && TREE_CODE (op0) == SSA_NAME - && TREE_CODE (op1) == SSA_NAME - && is_array_access_through_pointer_and_index (code, op0, op1, - &base, - &offset, - &offset_cast_stmt)) - 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; -} - - - -/* Helper for scan_for_refs. Check the operands of an assignment to - mark types that may escape. */ - -static void -check_assign (gimple t) -{ - /* First look on the lhs and see what variable is stored to */ - check_lhs_var (gimple_assign_lhs (t)); - - /* 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 (gimple_assign_rhs_code (t))) - { - case tcc_binary: - { - tree op0 = gimple_assign_rhs1 (t); - tree type0 = get_canon_type (TREE_TYPE (op0), false, false); - tree op1 = gimple_assign_rhs2 (t); - 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 (gimple_assign_rhs_code (t), op0, op1)) - mark_interesting_type (type0, FULL_ESCAPE); - - if (type1 && POINTER_TYPE_P (type1) - && !okay_pointer_operation (gimple_assign_rhs_code (t), op1, op0)) - mark_interesting_type (type1, FULL_ESCAPE); - - look_for_casts (op0); - look_for_casts (op1); - check_rhs_var (op0); - check_rhs_var (op1); - } - break; - - case tcc_unary: - { - tree op0 = gimple_assign_rhs1 (t); - 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 - && POINTER_TYPE_P (type0) - && (TREE_CODE (op0) == NEGATE_EXPR - || TREE_CODE (op0) == ABS_EXPR)) - mark_interesting_type (type0, FULL_ESCAPE); - - check_rhs_var (op0); - look_for_casts (op0); - } - break; - - case tcc_reference: - look_for_casts (gimple_assign_rhs1 (t)); - check_rhs_var (gimple_assign_rhs1 (t)); - break; - - case tcc_declaration: - check_rhs_var (gimple_assign_rhs1 (t)); - break; - - case tcc_expression: - if (gimple_assign_rhs_code (t) == ADDR_EXPR) - { - tree rhs = gimple_assign_rhs1 (t); - look_for_casts (TREE_OPERAND (rhs, 0)); - check_rhs_var (rhs); - } - break; - - default: - break; - } -} - - -/* Scan statement T for references to types and mark anything - interesting. */ - -static void -scan_for_refs (gimple t) -{ - switch (gimple_code (t)) - { - case GIMPLE_ASSIGN: - check_assign (t); - break; - - case GIMPLE_CALL: - /* If this is a call to malloc, squirrel away the result so we - do mark the resulting cast as being bad. */ - check_call (t); - break; - - case GIMPLE_ASM: - check_asm (t); - break; - - default: - break; - } - - return; -} - - -/* 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)) - check_tree (DECL_INITIAL (global)); -} - -/* 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) - { - gimple_stmt_iterator gsi; - for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi)) - scan_for_refs (gsi_stmt (gsi)); - } - } - - /* There may be const decls with interesting right hand sides. */ - if (DECL_STRUCT_FUNCTION (decl)) - { - tree var; - unsigned ix; - - FOR_EACH_LOCAL_DECL (DECL_STRUCT_FUNCTION (decl), ix, var) - { - if (TREE_CODE (var) == VAR_DECL - && DECL_INITIAL (var) - && !TREE_STATIC (var)) - check_tree (DECL_INITIAL (var)); - 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 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_set_bit (been_there_done_that, uid)) - return; - - /* 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 = DECL_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_set_bit (been_there_done_that, uid)) - return; - - /* 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_set_bit (been_there_done_that, uid)) - return; - - 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_set_bit (been_there_done_that, uid)) - return map; - - /* 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 && !node->clone_of) - 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_ipa_struct_reorg && flag_whole_program && (optimize > 0); -} - -struct simple_ipa_opt_pass pass_ipa_type_escape = -{ - { - SIMPLE_IPA_PASS, - "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 */ - } -}; |