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| author | kan <kan@FreeBSD.org> | 2007-05-19 01:19:51 +0000 |
|---|---|---|
| committer | kan <kan@FreeBSD.org> | 2007-05-19 01:19:51 +0000 |
| commit | 1f9ea4d0a40cca64d60cf4dab152349da7b9dddf (patch) | |
| tree | 0cb530c9c38af219e6dda2994c078b6b2b9ad853 /contrib/gcc/tree-ssa-structalias.c | |
| parent | 4895159b2b4f648051c1f139faa7b6dc50c2bfcb (diff) | |
| download | FreeBSD-src-1f9ea4d0a40cca64d60cf4dab152349da7b9dddf.zip FreeBSD-src-1f9ea4d0a40cca64d60cf4dab152349da7b9dddf.tar.gz | |
GCC 4.2.0 release.
Diffstat (limited to 'contrib/gcc/tree-ssa-structalias.c')
| -rw-r--r-- | contrib/gcc/tree-ssa-structalias.c | 5034 |
1 files changed, 5034 insertions, 0 deletions
diff --git a/contrib/gcc/tree-ssa-structalias.c b/contrib/gcc/tree-ssa-structalias.c new file mode 100644 index 0000000..550aa1c --- /dev/null +++ b/contrib/gcc/tree-ssa-structalias.c @@ -0,0 +1,5034 @@ +/* Tree based points-to analysis + Copyright (C) 2005, 2006 Free Software Foundation, Inc. + Contributed by Daniel Berlin <dberlin@dberlin.org> + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify +under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, 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; if not, write to the Free Software +Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA +*/ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "ggc.h" +#include "obstack.h" +#include "bitmap.h" +#include "flags.h" +#include "rtl.h" +#include "tm_p.h" +#include "hard-reg-set.h" +#include "basic-block.h" +#include "output.h" +#include "errors.h" +#include "diagnostic.h" +#include "tree.h" +#include "c-common.h" +#include "tree-flow.h" +#include "tree-inline.h" +#include "varray.h" +#include "c-tree.h" +#include "tree-gimple.h" +#include "hashtab.h" +#include "function.h" +#include "cgraph.h" +#include "tree-pass.h" +#include "timevar.h" +#include "alloc-pool.h" +#include "splay-tree.h" +#include "params.h" +#include "tree-ssa-structalias.h" +#include "cgraph.h" + +/* The idea behind this analyzer is to generate set constraints from the + program, then solve the resulting constraints in order to generate the + points-to sets. + + Set constraints are a way of modeling program analysis problems that + involve sets. They consist of an inclusion constraint language, + describing the variables (each variable is a set) and operations that + are involved on the variables, and a set of rules that derive facts + from these operations. To solve a system of set constraints, you derive + all possible facts under the rules, which gives you the correct sets + as a consequence. + + See "Efficient Field-sensitive pointer analysis for C" by "David + J. Pearce and Paul H. J. Kelly and Chris Hankin, at + http://citeseer.ist.psu.edu/pearce04efficient.html + + Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines + of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at + http://citeseer.ist.psu.edu/heintze01ultrafast.html + + There are three types of constraint expressions, DEREF, ADDRESSOF, and + SCALAR. Each constraint expression consists of a constraint type, + a variable, and an offset. + + SCALAR is a constraint expression type used to represent x, whether + it appears on the LHS or the RHS of a statement. + DEREF is a constraint expression type used to represent *x, whether + it appears on the LHS or the RHS of a statement. + ADDRESSOF is a constraint expression used to represent &x, whether + it appears on the LHS or the RHS of a statement. + + Each pointer variable in the program is assigned an integer id, and + each field of a structure variable is assigned an integer id as well. + + Structure variables are linked to their list of fields through a "next + field" in each variable that points to the next field in offset + order. + Each variable for a structure field has + + 1. "size", that tells the size in bits of that field. + 2. "fullsize, that tells the size in bits of the entire structure. + 3. "offset", that tells the offset in bits from the beginning of the + structure to this field. + + Thus, + struct f + { + int a; + int b; + } foo; + int *bar; + + looks like + + foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b + foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL + bar -> id 3, size 32, offset 0, fullsize 32, next NULL + + + In order to solve the system of set constraints, the following is + done: + + 1. Each constraint variable x has a solution set associated with it, + Sol(x). + + 2. Constraints are separated into direct, copy, and complex. + Direct constraints are ADDRESSOF constraints that require no extra + processing, such as P = &Q + Copy constraints are those of the form P = Q. + Complex constraints are all the constraints involving dereferences. + + 3. All direct constraints of the form P = &Q are processed, such + that Q is added to Sol(P) + + 4. All complex constraints for a given constraint variable are stored in a + linked list attached to that variable's node. + + 5. A directed graph is built out of the copy constraints. Each + constraint variable is a node in the graph, and an edge from + Q to P is added for each copy constraint of the form P = Q + + 6. The graph is then walked, and solution sets are + propagated along the copy edges, such that an edge from Q to P + causes Sol(P) <- Sol(P) union Sol(Q). + + 7. As we visit each node, all complex constraints associated with + that node are processed by adding appropriate copy edges to the graph, or the + appropriate variables to the solution set. + + 8. The process of walking the graph is iterated until no solution + sets change. + + Prior to walking the graph in steps 6 and 7, We perform static + cycle elimination on the constraint graph, as well + as off-line variable substitution. + + TODO: Adding offsets to pointer-to-structures can be handled (IE not punted + on and turned into anything), but isn't. You can just see what offset + inside the pointed-to struct it's going to access. + + TODO: Constant bounded arrays can be handled as if they were structs of the + same number of elements. + + TODO: Modeling heap and incoming pointers becomes much better if we + add fields to them as we discover them, which we could do. + + TODO: We could handle unions, but to be honest, it's probably not + worth the pain or slowdown. */ + +static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map))) +htab_t heapvar_for_stmt; + +/* One variable to represent all non-local accesses. */ +tree nonlocal_all; + +static bool use_field_sensitive = true; +static int in_ipa_mode = 0; +static bitmap_obstack predbitmap_obstack; +static bitmap_obstack ptabitmap_obstack; +static bitmap_obstack iteration_obstack; + +static unsigned int create_variable_info_for (tree, const char *); +static void build_constraint_graph (void); + +DEF_VEC_P(constraint_t); +DEF_VEC_ALLOC_P(constraint_t,heap); + +#define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \ + if (a) \ + EXECUTE_IF_SET_IN_BITMAP (a, b, c, d) + +static struct constraint_stats +{ + unsigned int total_vars; + unsigned int collapsed_vars; + unsigned int unified_vars_static; + unsigned int unified_vars_dynamic; + unsigned int iterations; + unsigned int num_edges; +} stats; + +struct variable_info +{ + /* ID of this variable */ + unsigned int id; + + /* Name of this variable */ + const char *name; + + /* Tree that this variable is associated with. */ + tree decl; + + /* Offset of this variable, in bits, from the base variable */ + unsigned HOST_WIDE_INT offset; + + /* Size of the variable, in bits. */ + unsigned HOST_WIDE_INT size; + + /* Full size of the base variable, in bits. */ + unsigned HOST_WIDE_INT fullsize; + + /* A link to the variable for the next field in this structure. */ + struct variable_info *next; + + /* Node in the graph that represents the constraints and points-to + solution for the variable. */ + unsigned int node; + + /* True if the address of this variable is taken. Needed for + variable substitution. */ + unsigned int address_taken:1; + + /* True if this variable is the target of a dereference. Needed for + variable substitution. */ + unsigned int indirect_target:1; + + /* True if the variable is directly the target of a dereference. + This is used to track which variables are *actually* dereferenced + so we can prune their points to listed. This is equivalent to the + indirect_target flag when no merging of variables happens. */ + unsigned int directly_dereferenced:1; + + /* True if this is a variable created by the constraint analysis, such as + heap variables and constraints we had to break up. */ + unsigned int is_artificial_var:1; + + /* True if this is a special variable whose solution set should not be + changed. */ + unsigned int is_special_var:1; + + /* True for variables whose size is not known or variable. */ + unsigned int is_unknown_size_var:1; + + /* True for variables that have unions somewhere in them. */ + unsigned int has_union:1; + + /* True if this is a heap variable. */ + unsigned int is_heap_var:1; + + /* Points-to set for this variable. */ + bitmap solution; + + /* Variable ids represented by this node. */ + bitmap variables; + + /* Vector of complex constraints for this node. Complex + constraints are those involving dereferences. */ + VEC(constraint_t,heap) *complex; + + /* Variable id this was collapsed to due to type unsafety. + This should be unused completely after build_constraint_graph, or + something is broken. */ + struct variable_info *collapsed_to; +}; +typedef struct variable_info *varinfo_t; + +static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT); + +/* Pool of variable info structures. */ +static alloc_pool variable_info_pool; + +DEF_VEC_P(varinfo_t); + +DEF_VEC_ALLOC_P(varinfo_t, heap); + +/* Table of variable info structures for constraint variables. Indexed directly + by variable info id. */ +static VEC(varinfo_t,heap) *varmap; + +/* Return the varmap element N */ + +static inline varinfo_t +get_varinfo (unsigned int n) +{ + return VEC_index(varinfo_t, varmap, n); +} + +/* Return the varmap element N, following the collapsed_to link. */ + +static inline varinfo_t +get_varinfo_fc (unsigned int n) +{ + varinfo_t v = VEC_index(varinfo_t, varmap, n); + + if (v->collapsed_to) + return v->collapsed_to; + return v; +} + +/* Variable that represents the unknown pointer. */ +static varinfo_t var_anything; +static tree anything_tree; +static unsigned int anything_id; + +/* Variable that represents the NULL pointer. */ +static varinfo_t var_nothing; +static tree nothing_tree; +static unsigned int nothing_id; + +/* Variable that represents read only memory. */ +static varinfo_t var_readonly; +static tree readonly_tree; +static unsigned int readonly_id; + +/* Variable that represents integers. This is used for when people do things + like &0->a.b. */ +static varinfo_t var_integer; +static tree integer_tree; +static unsigned int integer_id; + +/* Variable that represents escaped variables. This is used to give + incoming pointer variables a better set than ANYTHING. */ +static varinfo_t var_escaped_vars; +static tree escaped_vars_tree; +static unsigned int escaped_vars_id; + +/* Variable that represents non-local variables before we expand it to + one for each type. */ +static unsigned int nonlocal_vars_id; + +/* Lookup a heap var for FROM, and return it if we find one. */ + +static tree +heapvar_lookup (tree from) +{ + struct tree_map *h, in; + in.from = from; + + h = htab_find_with_hash (heapvar_for_stmt, &in, htab_hash_pointer (from)); + if (h) + return h->to; + return NULL_TREE; +} + +/* Insert a mapping FROM->TO in the heap var for statement + hashtable. */ + +static void +heapvar_insert (tree from, tree to) +{ + struct tree_map *h; + void **loc; + + h = ggc_alloc (sizeof (struct tree_map)); + h->hash = htab_hash_pointer (from); + h->from = from; + h->to = to; + loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->hash, INSERT); + *(struct tree_map **) loc = h; +} + +/* Return a new variable info structure consisting for a variable + named NAME, and using constraint graph node NODE. */ + +static varinfo_t +new_var_info (tree t, unsigned int id, const char *name, unsigned int node) +{ + varinfo_t ret = pool_alloc (variable_info_pool); + + ret->id = id; + ret->name = name; + ret->decl = t; + ret->node = node; + ret->address_taken = false; + ret->indirect_target = false; + ret->directly_dereferenced = false; + ret->is_artificial_var = false; + ret->is_heap_var = false; + ret->is_special_var = false; + ret->is_unknown_size_var = false; + ret->has_union = false; + ret->solution = BITMAP_ALLOC (&ptabitmap_obstack); + ret->variables = BITMAP_ALLOC (&ptabitmap_obstack); + ret->complex = NULL; + ret->next = NULL; + ret->collapsed_to = NULL; + return ret; +} + +typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type; + +/* An expression that appears in a constraint. */ + +struct constraint_expr +{ + /* Constraint type. */ + constraint_expr_type type; + + /* Variable we are referring to in the constraint. */ + unsigned int var; + + /* Offset, in bits, of this constraint from the beginning of + variables it ends up referring to. + + IOW, in a deref constraint, we would deref, get the result set, + then add OFFSET to each member. */ + unsigned HOST_WIDE_INT offset; +}; + +typedef struct constraint_expr ce_s; +DEF_VEC_O(ce_s); +DEF_VEC_ALLOC_O(ce_s, heap); +static void get_constraint_for (tree, VEC(ce_s, heap) **); +static void do_deref (VEC (ce_s, heap) **); + +/* Our set constraints are made up of two constraint expressions, one + LHS, and one RHS. + + As described in the introduction, our set constraints each represent an + operation between set valued variables. +*/ +struct constraint +{ + struct constraint_expr lhs; + struct constraint_expr rhs; +}; + +/* List of constraints that we use to build the constraint graph from. */ + +static VEC(constraint_t,heap) *constraints; +static alloc_pool constraint_pool; + +/* An edge in the weighted constraint graph. The edges are weighted, + with a bit set in weights meaning their is an edge with that + weight. + We don't keep the src in the edge, because we always know what it + is. */ + +struct constraint_edge +{ + unsigned int dest; + bitmap weights; +}; + +typedef struct constraint_edge *constraint_edge_t; +static alloc_pool constraint_edge_pool; + +/* Return a new constraint edge from SRC to DEST. */ + +static constraint_edge_t +new_constraint_edge (unsigned int dest) +{ + constraint_edge_t ret = pool_alloc (constraint_edge_pool); + ret->dest = dest; + ret->weights = NULL; + return ret; +} + +DEF_VEC_P(constraint_edge_t); +DEF_VEC_ALLOC_P(constraint_edge_t,heap); + + +/* The constraint graph is represented internally in two different + ways. The overwhelming majority of edges in the constraint graph + are zero weigh edges, and thus, using a vector of contrainst_edge_t + is a waste of time and memory, since they have no weights. We + simply use a bitmap to store the preds and succs for each node. + The weighted edges are stored as a set of adjacency vectors, one + per variable. succs[x] is the vector of successors for variable x, + and preds[x] is the vector of predecessors for variable x. IOW, + all edges are "forward" edges, which is not like our CFG. So + remember that preds[x]->src == x, and succs[x]->src == x. */ + +struct constraint_graph +{ + bitmap *zero_weight_succs; + bitmap *zero_weight_preds; + VEC(constraint_edge_t,heap) **succs; + VEC(constraint_edge_t,heap) **preds; +}; + +typedef struct constraint_graph *constraint_graph_t; + +static constraint_graph_t graph; +static int graph_size; + +/* Create a new constraint consisting of LHS and RHS expressions. */ + +static constraint_t +new_constraint (const struct constraint_expr lhs, + const struct constraint_expr rhs) +{ + constraint_t ret = pool_alloc (constraint_pool); + ret->lhs = lhs; + ret->rhs = rhs; + return ret; +} + +/* Print out constraint C to FILE. */ + +void +dump_constraint (FILE *file, constraint_t c) +{ + if (c->lhs.type == ADDRESSOF) + fprintf (file, "&"); + else if (c->lhs.type == DEREF) + fprintf (file, "*"); + fprintf (file, "%s", get_varinfo_fc (c->lhs.var)->name); + if (c->lhs.offset != 0) + fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset); + fprintf (file, " = "); + if (c->rhs.type == ADDRESSOF) + fprintf (file, "&"); + else if (c->rhs.type == DEREF) + fprintf (file, "*"); + fprintf (file, "%s", get_varinfo_fc (c->rhs.var)->name); + if (c->rhs.offset != 0) + fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset); + fprintf (file, "\n"); +} + +/* Print out constraint C to stderr. */ + +void +debug_constraint (constraint_t c) +{ + dump_constraint (stderr, c); +} + +/* Print out all constraints to FILE */ + +void +dump_constraints (FILE *file) +{ + int i; + constraint_t c; + for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) + dump_constraint (file, c); +} + +/* Print out all constraints to stderr. */ + +void +debug_constraints (void) +{ + dump_constraints (stderr); +} + +/* SOLVER FUNCTIONS + + The solver is a simple worklist solver, that works on the following + algorithm: + + sbitmap changed_nodes = all ones; + changed_count = number of nodes; + For each node that was already collapsed: + changed_count--; + + while (changed_count > 0) + { + compute topological ordering for constraint graph + + find and collapse cycles in the constraint graph (updating + changed if necessary) + + for each node (n) in the graph in topological order: + changed_count--; + + Process each complex constraint associated with the node, + updating changed if necessary. + + For each outgoing edge from n, propagate the solution from n to + the destination of the edge, updating changed as necessary. + + } */ + +/* Return true if two constraint expressions A and B are equal. */ + +static bool +constraint_expr_equal (struct constraint_expr a, struct constraint_expr b) +{ + return a.type == b.type && a.var == b.var && a.offset == b.offset; +} + +/* Return true if constraint expression A is less than constraint expression + B. This is just arbitrary, but consistent, in order to give them an + ordering. */ + +static bool +constraint_expr_less (struct constraint_expr a, struct constraint_expr b) +{ + if (a.type == b.type) + { + if (a.var == b.var) + return a.offset < b.offset; + else + return a.var < b.var; + } + else + return a.type < b.type; +} + +/* Return true if constraint A is less than constraint B. This is just + arbitrary, but consistent, in order to give them an ordering. */ + +static bool +constraint_less (const constraint_t a, const constraint_t b) +{ + if (constraint_expr_less (a->lhs, b->lhs)) + return true; + else if (constraint_expr_less (b->lhs, a->lhs)) + return false; + else + return constraint_expr_less (a->rhs, b->rhs); +} + +/* Return true if two constraints A and B are equal. */ + +static bool +constraint_equal (struct constraint a, struct constraint b) +{ + return constraint_expr_equal (a.lhs, b.lhs) + && constraint_expr_equal (a.rhs, b.rhs); +} + + +/* Find a constraint LOOKFOR in the sorted constraint vector VEC */ + +static constraint_t +constraint_vec_find (VEC(constraint_t,heap) *vec, + struct constraint lookfor) +{ + unsigned int place; + constraint_t found; + + if (vec == NULL) + return NULL; + + place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less); + if (place >= VEC_length (constraint_t, vec)) + return NULL; + found = VEC_index (constraint_t, vec, place); + if (!constraint_equal (*found, lookfor)) + return NULL; + return found; +} + +/* Union two constraint vectors, TO and FROM. Put the result in TO. */ + +static void +constraint_set_union (VEC(constraint_t,heap) **to, + VEC(constraint_t,heap) **from) +{ + int i; + constraint_t c; + + for (i = 0; VEC_iterate (constraint_t, *from, i, c); i++) + { + if (constraint_vec_find (*to, *c) == NULL) + { + unsigned int place = VEC_lower_bound (constraint_t, *to, c, + constraint_less); + VEC_safe_insert (constraint_t, heap, *to, place, c); + } + } +} + +/* Take a solution set SET, add OFFSET to each member of the set, and + overwrite SET with the result when done. */ + +static void +solution_set_add (bitmap set, unsigned HOST_WIDE_INT offset) +{ + bitmap result = BITMAP_ALLOC (&iteration_obstack); + unsigned int i; + bitmap_iterator bi; + + EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) + { + /* If this is a properly sized variable, only add offset if it's + less than end. Otherwise, it is globbed to a single + variable. */ + + if ((get_varinfo (i)->offset + offset) < get_varinfo (i)->fullsize) + { + unsigned HOST_WIDE_INT fieldoffset = get_varinfo (i)->offset + offset; + varinfo_t v = first_vi_for_offset (get_varinfo (i), fieldoffset); + if (!v) + continue; + bitmap_set_bit (result, v->id); + } + else if (get_varinfo (i)->is_artificial_var + || get_varinfo (i)->has_union + || get_varinfo (i)->is_unknown_size_var) + { + bitmap_set_bit (result, i); + } + } + + bitmap_copy (set, result); + BITMAP_FREE (result); +} + +/* Union solution sets TO and FROM, and add INC to each member of FROM in the + process. */ + +static bool +set_union_with_increment (bitmap to, bitmap from, unsigned HOST_WIDE_INT inc) +{ + if (inc == 0) + return bitmap_ior_into (to, from); + else + { + bitmap tmp; + bool res; + + tmp = BITMAP_ALLOC (&iteration_obstack); + bitmap_copy (tmp, from); + solution_set_add (tmp, inc); + res = bitmap_ior_into (to, tmp); + BITMAP_FREE (tmp); + return res; + } +} + +/* Insert constraint C into the list of complex constraints for VAR. */ + +static void +insert_into_complex (unsigned int var, constraint_t c) +{ + varinfo_t vi = get_varinfo (var); + unsigned int place = VEC_lower_bound (constraint_t, vi->complex, c, + constraint_less); + VEC_safe_insert (constraint_t, heap, vi->complex, place, c); +} + + +/* Compare two constraint edges A and B, return true if they are equal. */ + +static bool +constraint_edge_equal (struct constraint_edge a, struct constraint_edge b) +{ + return a.dest == b.dest; +} + +/* Compare two constraint edges, return true if A is less than B */ + +static bool +constraint_edge_less (const constraint_edge_t a, const constraint_edge_t b) +{ + if (a->dest < b->dest) + return true; + return false; +} + +/* Find the constraint edge that matches LOOKFOR, in VEC. + Return the edge, if found, NULL otherwise. */ + +static constraint_edge_t +constraint_edge_vec_find (VEC(constraint_edge_t,heap) *vec, + struct constraint_edge lookfor) +{ + unsigned int place; + constraint_edge_t edge = NULL; + + place = VEC_lower_bound (constraint_edge_t, vec, &lookfor, + constraint_edge_less); + if (place >= VEC_length (constraint_edge_t, vec)) + return NULL; + edge = VEC_index (constraint_edge_t, vec, place); + if (!constraint_edge_equal (*edge, lookfor)) + return NULL; + return edge; +} + +/* Condense two variable nodes into a single variable node, by moving + all associated info from SRC to TO. */ + +static void +condense_varmap_nodes (unsigned int to, unsigned int src) +{ + varinfo_t tovi = get_varinfo (to); + varinfo_t srcvi = get_varinfo (src); + unsigned int i; + constraint_t c; + bitmap_iterator bi; + + /* the src node, and all its variables, are now the to node. */ + srcvi->node = to; + EXECUTE_IF_SET_IN_BITMAP (srcvi->variables, 0, i, bi) + get_varinfo (i)->node = to; + + /* Merge the src node variables and the to node variables. */ + bitmap_set_bit (tovi->variables, src); + bitmap_ior_into (tovi->variables, srcvi->variables); + bitmap_clear (srcvi->variables); + + /* Move all complex constraints from src node into to node */ + for (i = 0; VEC_iterate (constraint_t, srcvi->complex, i, c); i++) + { + /* In complex constraints for node src, we may have either + a = *src, and *src = a. */ + + if (c->rhs.type == DEREF) + c->rhs.var = to; + else + c->lhs.var = to; + } + constraint_set_union (&tovi->complex, &srcvi->complex); + VEC_free (constraint_t, heap, srcvi->complex); + srcvi->complex = NULL; +} + +/* Erase an edge from SRC to SRC from GRAPH. This routine only + handles self-edges (e.g. an edge from a to a). */ + +static void +erase_graph_self_edge (constraint_graph_t graph, unsigned int src) +{ + VEC(constraint_edge_t,heap) *predvec = graph->preds[src]; + VEC(constraint_edge_t,heap) *succvec = graph->succs[src]; + struct constraint_edge edge; + unsigned int place; + + edge.dest = src; + + /* Remove from the successors. */ + place = VEC_lower_bound (constraint_edge_t, succvec, &edge, + constraint_edge_less); + + /* Make sure we found the edge. */ +#ifdef ENABLE_CHECKING + { + constraint_edge_t tmp = VEC_index (constraint_edge_t, succvec, place); + gcc_assert (constraint_edge_equal (*tmp, edge)); + } +#endif + VEC_ordered_remove (constraint_edge_t, succvec, place); + + /* Remove from the predecessors. */ + place = VEC_lower_bound (constraint_edge_t, predvec, &edge, + constraint_edge_less); + + /* Make sure we found the edge. */ +#ifdef ENABLE_CHECKING + { + constraint_edge_t tmp = VEC_index (constraint_edge_t, predvec, place); + gcc_assert (constraint_edge_equal (*tmp, edge)); + } +#endif + VEC_ordered_remove (constraint_edge_t, predvec, place); +} + +/* Remove edges involving NODE from GRAPH. */ + +static void +clear_edges_for_node (constraint_graph_t graph, unsigned int node) +{ + VEC(constraint_edge_t,heap) *succvec = graph->succs[node]; + VEC(constraint_edge_t,heap) *predvec = graph->preds[node]; + bitmap_iterator bi; + unsigned int j; + constraint_edge_t c = NULL; + int i; + + /* Walk the successors, erase the associated preds. */ + + EXECUTE_IF_IN_NONNULL_BITMAP (graph->zero_weight_succs[node], 0, j, bi) + if (j != node) + bitmap_clear_bit (graph->zero_weight_preds[j], node); + + for (i = 0; VEC_iterate (constraint_edge_t, succvec, i, c); i++) + if (c->dest != node) + { + unsigned int place; + struct constraint_edge lookfor; + constraint_edge_t result; + + lookfor.dest = node; + place = VEC_lower_bound (constraint_edge_t, graph->preds[c->dest], + &lookfor, constraint_edge_less); + result = VEC_ordered_remove (constraint_edge_t, + graph->preds[c->dest], place); + pool_free (constraint_edge_pool, result); + } + + /* Walk the preds, erase the associated succs. */ + + EXECUTE_IF_IN_NONNULL_BITMAP (graph->zero_weight_preds[node], 0, j, bi) + if (j != node) + bitmap_clear_bit (graph->zero_weight_succs[j], node); + + for (i =0; VEC_iterate (constraint_edge_t, predvec, i, c); i++) + if (c->dest != node) + { + unsigned int place; + struct constraint_edge lookfor; + constraint_edge_t result; + + lookfor.dest = node; + place = VEC_lower_bound (constraint_edge_t, graph->succs[c->dest], + &lookfor, constraint_edge_less); + result = VEC_ordered_remove (constraint_edge_t, + graph->succs[c->dest], place); + pool_free (constraint_edge_pool, result); + + } + + if (graph->zero_weight_preds[node]) + { + BITMAP_FREE (graph->zero_weight_preds[node]); + graph->zero_weight_preds[node] = NULL; + } + + if (graph->zero_weight_succs[node]) + { + BITMAP_FREE (graph->zero_weight_succs[node]); + graph->zero_weight_succs[node] = NULL; + } + + VEC_free (constraint_edge_t, heap, graph->preds[node]); + VEC_free (constraint_edge_t, heap, graph->succs[node]); + graph->preds[node] = NULL; + graph->succs[node] = NULL; +} + +static bool edge_added = false; + +/* Add edge (src, dest) to the graph. */ + +static bool +add_graph_edge (constraint_graph_t graph, unsigned int src, unsigned int dest) +{ + unsigned int place; + VEC(constraint_edge_t,heap) *vec; + struct constraint_edge newe; + newe.dest = dest; + + vec = graph->preds[src]; + place = VEC_lower_bound (constraint_edge_t, vec, &newe, + constraint_edge_less); + if (place == VEC_length (constraint_edge_t, vec) + || VEC_index (constraint_edge_t, vec, place)->dest != dest) + { + constraint_edge_t edge = new_constraint_edge (dest); + + VEC_safe_insert (constraint_edge_t, heap, graph->preds[src], + place, edge); + edge = new_constraint_edge (src); + + place = VEC_lower_bound (constraint_edge_t, graph->succs[dest], + edge, constraint_edge_less); + VEC_safe_insert (constraint_edge_t, heap, graph->succs[dest], + place, edge); + edge_added = true; + stats.num_edges++; + return true; + } + else + return false; +} + + +/* Return the bitmap representing the weights of edge (SRC, DEST). */ + +static bitmap * +get_graph_weights (constraint_graph_t graph, unsigned int src, + unsigned int dest) +{ + constraint_edge_t edge; + VEC(constraint_edge_t,heap) *vec; + struct constraint_edge lookfor; + + lookfor.dest = dest; + + vec = graph->preds[src]; + edge = constraint_edge_vec_find (vec, lookfor); + gcc_assert (edge != NULL); + return &edge->weights; +} + +/* Allocate graph weight bitmap for the edges associated with SRC and + DEST in GRAPH. Both the pred and the succ edges share a single + bitmap, so we need to set both edges to that bitmap. */ + +static bitmap +allocate_graph_weights (constraint_graph_t graph, unsigned int src, + unsigned int dest) +{ + bitmap result; + constraint_edge_t edge; + VEC(constraint_edge_t,heap) *vec; + struct constraint_edge lookfor; + + result = BITMAP_ALLOC (&ptabitmap_obstack); + + /* Set the pred weight. */ + lookfor.dest = dest; + vec = graph->preds[src]; + edge = constraint_edge_vec_find (vec, lookfor); + gcc_assert (edge != NULL); + edge->weights = result; + + /* Set the succ weight. */ + lookfor.dest = src; + vec = graph->succs[dest]; + edge = constraint_edge_vec_find (vec, lookfor); + gcc_assert (edge != NULL); + edge->weights = result; + + return result; +} + + +/* Merge GRAPH nodes FROM and TO into node TO. */ + +static void +merge_graph_nodes (constraint_graph_t graph, unsigned int to, + unsigned int from) +{ + VEC(constraint_edge_t,heap) *succvec = graph->succs[from]; + VEC(constraint_edge_t,heap) *predvec = graph->preds[from]; + int i; + constraint_edge_t c; + unsigned int j; + bitmap_iterator bi; + + /* Merge all the zero weighted predecessor edges. */ + if (graph->zero_weight_preds[from]) + { + if (!graph->zero_weight_preds[to]) + graph->zero_weight_preds[to] = BITMAP_ALLOC (&predbitmap_obstack); + + EXECUTE_IF_SET_IN_BITMAP (graph->zero_weight_preds[from], 0, j, bi) + { + if (j != to) + { + bitmap_clear_bit (graph->zero_weight_succs[j], from); + bitmap_set_bit (graph->zero_weight_succs[j], to); + } + } + bitmap_ior_into (graph->zero_weight_preds[to], + graph->zero_weight_preds[from]); + } + + /* Merge all the zero weighted successor edges. */ + if (graph->zero_weight_succs[from]) + { + if (!graph->zero_weight_succs[to]) + graph->zero_weight_succs[to] = BITMAP_ALLOC (&ptabitmap_obstack); + EXECUTE_IF_SET_IN_BITMAP (graph->zero_weight_succs[from], 0, j, bi) + { + bitmap_clear_bit (graph->zero_weight_preds[j], from); + bitmap_set_bit (graph->zero_weight_preds[j], to); + } + bitmap_ior_into (graph->zero_weight_succs[to], + graph->zero_weight_succs[from]); + } + + /* Merge all the nonzero weighted predecessor edges. */ + for (i = 0; VEC_iterate (constraint_edge_t, predvec, i, c); i++) + { + unsigned int d = c->dest; + bitmap temp; + bitmap *weights; + + if (c->dest == from) + d = to; + + add_graph_edge (graph, to, d); + + temp = *(get_graph_weights (graph, from, c->dest)); + if (temp) + { + weights = get_graph_weights (graph, to, d); + if (!*weights) + *weights = allocate_graph_weights (graph, to, d); + + bitmap_ior_into (*weights, temp); + } + + } + + /* Merge all the nonzero weighted successor edges. */ + for (i = 0; VEC_iterate (constraint_edge_t, succvec, i, c); i++) + { + unsigned int d = c->dest; + bitmap temp; + bitmap *weights; + + if (c->dest == from) + d = to; + + add_graph_edge (graph, d, to); + + temp = *(get_graph_weights (graph, c->dest, from)); + if (temp) + { + weights = get_graph_weights (graph, d, to); + if (!*weights) + *weights = allocate_graph_weights (graph, d, to); + bitmap_ior_into (*weights, temp); + } + } + clear_edges_for_node (graph, from); +} + +/* Add a graph edge to GRAPH, going from TO to FROM, with WEIGHT, if + it doesn't exist in the graph already. + Return false if the edge already existed, true otherwise. */ + +static bool +int_add_graph_edge (constraint_graph_t graph, unsigned int to, + unsigned int from, unsigned HOST_WIDE_INT weight) +{ + if (to == from && weight == 0) + { + return false; + } + else + { + bool r = false; + + if (weight == 0) + { + if (!graph->zero_weight_preds[to]) + graph->zero_weight_preds[to] = BITMAP_ALLOC (&predbitmap_obstack); + if (!graph->zero_weight_succs[from]) + graph->zero_weight_succs[from] = BITMAP_ALLOC (&ptabitmap_obstack); + if (!bitmap_bit_p (graph->zero_weight_succs[from], to)) + { + edge_added = true; + r = true; + stats.num_edges++; + bitmap_set_bit (graph->zero_weight_preds[to], from); + bitmap_set_bit (graph->zero_weight_succs[from], to); + } + } + else + { + bitmap *weights; + + r = add_graph_edge (graph, to, from); + weights = get_graph_weights (graph, to, from); + + if (!*weights) + { + r = true; + *weights = allocate_graph_weights (graph, to, from); + bitmap_set_bit (*weights, weight); + } + else + { + r |= !bitmap_bit_p (*weights, weight); + bitmap_set_bit (*weights, weight); + } + } + + return r; + } +} + + +/* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */ + +static bool +valid_graph_edge (constraint_graph_t graph, unsigned int src, + unsigned int dest) +{ + struct constraint_edge lookfor; + lookfor.dest = src; + + return (graph->zero_weight_succs[dest] + && bitmap_bit_p (graph->zero_weight_succs[dest], src)) + || constraint_edge_vec_find (graph->succs[dest], lookfor) != NULL; +} + +/* Return true if {DEST, SRC} is an existing weighted graph edge (IE has + a weight other than 0) in GRAPH. */ +static bool +valid_weighted_graph_edge (constraint_graph_t graph, unsigned int src, + unsigned int dest) +{ + struct constraint_edge lookfor; + lookfor.dest = src; + + return graph->preds[src] + && constraint_edge_vec_find (graph->succs[dest], lookfor) != NULL; +} + + +/* Build the constraint graph. */ + +static void +build_constraint_graph (void) +{ + int i = 0; + constraint_t c; + + graph = XNEW (struct constraint_graph); + graph_size = VEC_length (varinfo_t, varmap) + 1; + graph->succs = XCNEWVEC (VEC(constraint_edge_t,heap) *, graph_size); + graph->preds = XCNEWVEC (VEC(constraint_edge_t,heap) *, graph_size); + graph->zero_weight_succs = XCNEWVEC (bitmap, graph_size); + graph->zero_weight_preds = XCNEWVEC (bitmap, graph_size); + + for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++) + { + struct constraint_expr lhs = c->lhs; + struct constraint_expr rhs = c->rhs; + unsigned int lhsvar = get_varinfo_fc (lhs.var)->id; + unsigned int rhsvar = get_varinfo_fc (rhs.var)->id; + + if (lhs.type == DEREF) + { + /* *x = y or *x = &y (complex) */ + if (rhs.type == ADDRESSOF || rhsvar > anything_id) + insert_into_complex (lhsvar, c); + } + else if (rhs.type == DEREF) + { + /* !special var= *y */ + if (!(get_varinfo (lhsvar)->is_special_var)) + insert_into_complex (rhsvar, c); + } + else if (rhs.type == ADDRESSOF) + { + /* x = &y */ + bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar); + } + else if (lhsvar > anything_id) + { + /* Ignore 0 weighted self edges, as they can't possibly contribute + anything */ + if (lhsvar != rhsvar || rhs.offset != 0 || lhs.offset != 0) + { + /* x = y (simple) */ + int_add_graph_edge (graph, lhs.var, rhs.var, rhs.offset); + } + + } + } +} + + +/* Changed variables on the last iteration. */ +static unsigned int changed_count; +static sbitmap changed; + +DEF_VEC_I(unsigned); +DEF_VEC_ALLOC_I(unsigned,heap); + + +/* Strongly Connected Component visitation info. */ + +struct scc_info +{ + sbitmap visited; + sbitmap in_component; + int current_index; + unsigned int *visited_index; + VEC(unsigned,heap) *scc_stack; + VEC(unsigned,heap) *unification_queue; +}; + + +/* Recursive routine to find strongly connected components in GRAPH. + SI is the SCC info to store the information in, and N is the id of current + graph node we are processing. + + This is Tarjan's strongly connected component finding algorithm, as + modified by Nuutila to keep only non-root nodes on the stack. + The algorithm can be found in "On finding the strongly connected + connected components in a directed graph" by Esko Nuutila and Eljas + Soisalon-Soininen, in Information Processing Letters volume 49, + number 1, pages 9-14. */ + +static void +scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n) +{ + unsigned int i; + bitmap_iterator bi; + + gcc_assert (get_varinfo (n)->node == n); + SET_BIT (si->visited, n); + RESET_BIT (si->in_component, n); + si->visited_index[n] = si->current_index ++; + + /* Visit all the successors. */ + EXECUTE_IF_IN_NONNULL_BITMAP (graph->zero_weight_succs[n], 0, i, bi) + { + unsigned int w = i; + if (!TEST_BIT (si->visited, w)) + scc_visit (graph, si, w); + if (!TEST_BIT (si->in_component, w)) + { + unsigned int t = get_varinfo (w)->node; + unsigned int nnode = get_varinfo (n)->node; + if (si->visited_index[t] < si->visited_index[nnode]) + get_varinfo (n)->node = t; + } + } + + /* See if any components have been identified. */ + if (get_varinfo (n)->node == n) + { + unsigned int t = si->visited_index[n]; + SET_BIT (si->in_component, n); + while (VEC_length (unsigned, si->scc_stack) != 0 + && t < si->visited_index[VEC_last (unsigned, si->scc_stack)]) + { + unsigned int w = VEC_pop (unsigned, si->scc_stack); + get_varinfo (w)->node = n; + SET_BIT (si->in_component, w); + /* Mark this node for collapsing. */ + VEC_safe_push (unsigned, heap, si->unification_queue, w); + } + } + else + VEC_safe_push (unsigned, heap, si->scc_stack, n); +} + + +/* Collapse two variables into one variable. */ + +static void +collapse_nodes (constraint_graph_t graph, unsigned int to, unsigned int from) +{ + bitmap tosol, fromsol; + + condense_varmap_nodes (to, from); + tosol = get_varinfo (to)->solution; + fromsol = get_varinfo (from)->solution; + bitmap_ior_into (tosol, fromsol); + merge_graph_nodes (graph, to, from); + + if (valid_graph_edge (graph, to, to)) + { + if (graph->zero_weight_preds[to]) + { + bitmap_clear_bit (graph->zero_weight_preds[to], to); + bitmap_clear_bit (graph->zero_weight_succs[to], to); + } + if (valid_weighted_graph_edge (graph, to, to)) + { + bitmap weights = *(get_graph_weights (graph, to, to)); + if (!weights || bitmap_empty_p (weights)) + erase_graph_self_edge (graph, to); + } + } + BITMAP_FREE (fromsol); + get_varinfo (to)->address_taken |= get_varinfo (from)->address_taken; + get_varinfo (to)->indirect_target |= get_varinfo (from)->indirect_target; +} + + +/* Unify nodes in GRAPH that we have found to be part of a cycle. + SI is the Strongly Connected Components information structure that tells us + what components to unify. + UPDATE_CHANGED should be set to true if the changed sbitmap and changed + count should be updated to reflect the unification. */ + +static void +process_unification_queue (constraint_graph_t graph, struct scc_info *si, + bool update_changed) +{ + size_t i = 0; + bitmap tmp = BITMAP_ALLOC (update_changed ? &iteration_obstack : NULL); + bitmap_clear (tmp); + + /* We proceed as follows: + + For each component in the queue (components are delineated by + when current_queue_element->node != next_queue_element->node): + + rep = representative node for component + + For each node (tounify) to be unified in the component, + merge the solution for tounify into tmp bitmap + + clear solution for tounify + + merge edges from tounify into rep + + merge complex constraints from tounify into rep + + update changed count to note that tounify will never change + again + + Merge tmp into solution for rep, marking rep changed if this + changed rep's solution. + + Delete any 0 weighted self-edges we now have for rep. */ + while (i != VEC_length (unsigned, si->unification_queue)) + { + unsigned int tounify = VEC_index (unsigned, si->unification_queue, i); + unsigned int n = get_varinfo (tounify)->node; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Unifying %s to %s\n", + get_varinfo (tounify)->name, + get_varinfo (n)->name); + if (update_changed) + stats.unified_vars_dynamic++; + else + stats.unified_vars_static++; + bitmap_ior_into (tmp, get_varinfo (tounify)->solution); + merge_graph_nodes (graph, n, tounify); + condense_varmap_nodes (n, tounify); + + if (update_changed && TEST_BIT (changed, tounify)) + { + RESET_BIT (changed, tounify); + if (!TEST_BIT (changed, n)) + SET_BIT (changed, n); + else + { + gcc_assert (changed_count > 0); + changed_count--; + } + } + + bitmap_clear (get_varinfo (tounify)->solution); + ++i; + + /* If we've either finished processing the entire queue, or + finished processing all nodes for component n, update the solution for + n. */ + if (i == VEC_length (unsigned, si->unification_queue) + || get_varinfo (VEC_index (unsigned, si->unification_queue, i))->node != n) + { + /* If the solution changes because of the merging, we need to mark + the variable as changed. */ + if (bitmap_ior_into (get_varinfo (n)->solution, tmp)) + { + if (update_changed && !TEST_BIT (changed, n)) + { + SET_BIT (changed, n); + changed_count++; + } + } + bitmap_clear (tmp); + + if (valid_graph_edge (graph, n, n)) + { + if (graph->zero_weight_succs[n]) + { + if (graph->zero_weight_preds[n]) + bitmap_clear_bit (graph->zero_weight_preds[n], n); + bitmap_clear_bit (graph->zero_weight_succs[n], n); + } + if (valid_weighted_graph_edge (graph, n, n)) + { + bitmap weights = *(get_graph_weights (graph, n, n)); + if (!weights || bitmap_empty_p (weights)) + erase_graph_self_edge (graph, n); + } + } + } + } + BITMAP_FREE (tmp); +} + + +/* Information needed to compute the topological ordering of a graph. */ + +struct topo_info +{ + /* sbitmap of visited nodes. */ + sbitmap visited; + /* Array that stores the topological order of the graph, *in + reverse*. */ + VEC(unsigned,heap) *topo_order; +}; + + +/* Initialize and return a topological info structure. */ + +static struct topo_info * +init_topo_info (void) +{ + size_t size = VEC_length (varinfo_t, varmap); + struct topo_info *ti = XNEW (struct topo_info); + ti->visited = sbitmap_alloc (size); + sbitmap_zero (ti->visited); + ti->topo_order = VEC_alloc (unsigned, heap, 1); + return ti; +} + + +/* Free the topological sort info pointed to by TI. */ + +static void +free_topo_info (struct topo_info *ti) +{ + sbitmap_free (ti->visited); + VEC_free (unsigned, heap, ti->topo_order); + free (ti); +} + +/* Visit the graph in topological order, and store the order in the + topo_info structure. */ + +static void +topo_visit (constraint_graph_t graph, struct topo_info *ti, + unsigned int n) +{ + VEC(constraint_edge_t,heap) *succs = graph->succs[n]; + bitmap temp; + bitmap_iterator bi; + constraint_edge_t c; + int i; + unsigned int j; + + SET_BIT (ti->visited, n); + if (VEC_length (constraint_edge_t, succs) != 0) + { + temp = BITMAP_ALLOC (&iteration_obstack); + if (graph->zero_weight_succs[n]) + bitmap_ior_into (temp, graph->zero_weight_succs[n]); + for (i = 0; VEC_iterate (constraint_edge_t, succs, i, c); i++) + bitmap_set_bit (temp, c->dest); + } + else + temp = graph->zero_weight_succs[n]; + + if (temp) + EXECUTE_IF_SET_IN_BITMAP (temp, 0, j, bi) + { + if (!TEST_BIT (ti->visited, j)) + topo_visit (graph, ti, j); + } + VEC_safe_push (unsigned, heap, ti->topo_order, n); +} + +/* Return true if variable N + OFFSET is a legal field of N. */ + +static bool +type_safe (unsigned int n, unsigned HOST_WIDE_INT *offset) +{ + varinfo_t ninfo = get_varinfo (n); + + /* For things we've globbed to single variables, any offset into the + variable acts like the entire variable, so that it becomes offset + 0. */ + if (ninfo->is_special_var + || ninfo->is_artificial_var + || ninfo->is_unknown_size_var) + { + *offset = 0; + return true; + } + return (get_varinfo (n)->offset + *offset) < get_varinfo (n)->fullsize; +} + +/* Process a constraint C that represents *x = &y. */ + +static void +do_da_constraint (constraint_graph_t graph ATTRIBUTE_UNUSED, + constraint_t c, bitmap delta) +{ + unsigned int rhs = c->rhs.var; + unsigned int j; + bitmap_iterator bi; + + /* For each member j of Delta (Sol(x)), add x to Sol(j) */ + EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) + { + unsigned HOST_WIDE_INT offset = c->lhs.offset; + if (type_safe (j, &offset) && !(get_varinfo (j)->is_special_var)) + { + /* *x != NULL && *x != ANYTHING*/ + varinfo_t v; + unsigned int t; + bitmap sol; + unsigned HOST_WIDE_INT fieldoffset = get_varinfo (j)->offset + offset; + + v = first_vi_for_offset (get_varinfo (j), fieldoffset); + if (!v) + continue; + t = v->node; + sol = get_varinfo (t)->solution; + if (!bitmap_bit_p (sol, rhs)) + { + bitmap_set_bit (sol, rhs); + if (!TEST_BIT (changed, t)) + { + SET_BIT (changed, t); + changed_count++; + } + } + } + else if (0 && dump_file && !(get_varinfo (j)->is_special_var)) + fprintf (dump_file, "Untypesafe usage in do_da_constraint.\n"); + + } +} + +/* Process a constraint C that represents x = *y, using DELTA as the + starting solution. */ + +static void +do_sd_constraint (constraint_graph_t graph, constraint_t c, + bitmap delta) +{ + unsigned int lhs = get_varinfo (c->lhs.var)->node; + bool flag = false; + bitmap sol = get_varinfo (lhs)->solution; + unsigned int j; + bitmap_iterator bi; + + if (bitmap_bit_p (delta, anything_id)) + { + flag = !bitmap_bit_p (sol, anything_id); + if (flag) + bitmap_set_bit (sol, anything_id); + goto done; + } + /* For each variable j in delta (Sol(y)), add + an edge in the graph from j to x, and union Sol(j) into Sol(x). */ + EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) + { + unsigned HOST_WIDE_INT roffset = c->rhs.offset; + if (type_safe (j, &roffset)) + { + varinfo_t v; + unsigned HOST_WIDE_INT fieldoffset = get_varinfo (j)->offset + roffset; + unsigned int t; + + v = first_vi_for_offset (get_varinfo (j), fieldoffset); + if (!v) + continue; + t = v->node; + + /* Adding edges from the special vars is pointless. + They don't have sets that can change. */ + if (get_varinfo (t) ->is_special_var) + flag |= bitmap_ior_into (sol, get_varinfo (t)->solution); + else if (int_add_graph_edge (graph, lhs, t, 0)) + flag |= bitmap_ior_into (sol, get_varinfo (t)->solution); + } + else if (0 && dump_file && !(get_varinfo (j)->is_special_var)) + fprintf (dump_file, "Untypesafe usage in do_sd_constraint\n"); + + } + +done: + /* If the LHS solution changed, mark the var as changed. */ + if (flag) + { + get_varinfo (lhs)->solution = sol; + if (!TEST_BIT (changed, lhs)) + { + SET_BIT (changed, lhs); + changed_count++; + } + } +} + +/* Process a constraint C that represents *x = y. */ + +static void +do_ds_constraint (constraint_graph_t graph, constraint_t c, bitmap delta) +{ + unsigned int rhs = get_varinfo (c->rhs.var)->node; + unsigned HOST_WIDE_INT roff = c->rhs.offset; + bitmap sol = get_varinfo (rhs)->solution; + unsigned int j; + bitmap_iterator bi; + + if (bitmap_bit_p (sol, anything_id)) + { + EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) + { + varinfo_t jvi = get_varinfo (j); + unsigned int t; + unsigned int loff = c->lhs.offset; + unsigned HOST_WIDE_INT fieldoffset = jvi->offset + loff; + varinfo_t v; + + v = first_vi_for_offset (get_varinfo (j), fieldoffset); + if (!v) + continue; + t = v->node; + + if (!bitmap_bit_p (get_varinfo (t)->solution, anything_id)) + { + bitmap_set_bit (get_varinfo (t)->solution, anything_id); + if (!TEST_BIT (changed, t)) + { + SET_BIT (changed, t); + changed_count++; + } + } + } + return; + } + + /* For each member j of delta (Sol(x)), add an edge from y to j and + union Sol(y) into Sol(j) */ + EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi) + { + unsigned HOST_WIDE_INT loff = c->lhs.offset; + if (type_safe (j, &loff) && !(get_varinfo(j)->is_special_var)) + { + varinfo_t v; + unsigned int t; + unsigned HOST_WIDE_INT fieldoffset = get_varinfo (j)->offset + loff; + + v = first_vi_for_offset (get_varinfo (j), fieldoffset); + if (!v) + continue; + t = v->node; + if (int_add_graph_edge (graph, t, rhs, roff)) + { + bitmap tmp = get_varinfo (t)->solution; + if (set_union_with_increment (tmp, sol, roff)) + { + get_varinfo (t)->solution = tmp; + if (t == rhs) + sol = get_varinfo (rhs)->solution; + if (!TEST_BIT (changed, t)) + { + SET_BIT (changed, t); + changed_count++; + } + } + } + } + else if (0 && dump_file && !(get_varinfo (j)->is_special_var)) + fprintf (dump_file, "Untypesafe usage in do_ds_constraint\n"); + } +} + +/* Handle a non-simple (simple meaning requires no iteration), non-copy + constraint (IE *x = &y, x = *y, and *x = y). */ + +static void +do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta) +{ + if (c->lhs.type == DEREF) + { + if (c->rhs.type == ADDRESSOF) + { + /* *x = &y */ + do_da_constraint (graph, c, delta); + } + else + { + /* *x = y */ + do_ds_constraint (graph, c, delta); + } + } + else + { + /* x = *y */ + if (!(get_varinfo (c->lhs.var)->is_special_var)) + do_sd_constraint (graph, c, delta); + } +} + +/* Initialize and return a new SCC info structure. */ + +static struct scc_info * +init_scc_info (void) +{ + struct scc_info *si = XNEW (struct scc_info); + size_t size = VEC_length (varinfo_t, varmap); + + si->current_index = 0; + si->visited = sbitmap_alloc (size); + sbitmap_zero (si->visited); + si->in_component = sbitmap_alloc (size); + sbitmap_ones (si->in_component); + si->visited_index = XCNEWVEC (unsigned int, size + 1); + si->scc_stack = VEC_alloc (unsigned, heap, 1); + si->unification_queue = VEC_alloc (unsigned, heap, 1); + return si; +} + +/* Free an SCC info structure pointed to by SI */ + +static void +free_scc_info (struct scc_info *si) +{ + sbitmap_free (si->visited); + sbitmap_free (si->in_component); + free (si->visited_index); + VEC_free (unsigned, heap, si->scc_stack); + VEC_free (unsigned, heap, si->unification_queue); + free(si); +} + + +/* Find cycles in GRAPH that occur, using strongly connected components, and + collapse the cycles into a single representative node. if UPDATE_CHANGED + is true, then update the changed sbitmap to note those nodes whose + solutions have changed as a result of collapsing. */ + +static void +find_and_collapse_graph_cycles (constraint_graph_t graph, bool update_changed) +{ + unsigned int i; + unsigned int size = VEC_length (varinfo_t, varmap); + struct scc_info *si = init_scc_info (); + + for (i = 0; i != size; ++i) + if (!TEST_BIT (si->visited, i) && get_varinfo (i)->node == i) + scc_visit (graph, si, i); + + process_unification_queue (graph, si, update_changed); + free_scc_info (si); +} + +/* Compute a topological ordering for GRAPH, and store the result in the + topo_info structure TI. */ + +static void +compute_topo_order (constraint_graph_t graph, + struct topo_info *ti) +{ + unsigned int i; + unsigned int size = VEC_length (varinfo_t, varmap); + + for (i = 0; i != size; ++i) + if (!TEST_BIT (ti->visited, i) && get_varinfo (i)->node == i) + topo_visit (graph, ti, i); +} + +/* Return true if bitmap B is empty, or a bitmap other than bit 0 is set. */ + +static bool +bitmap_other_than_zero_bit_set (bitmap b) +{ + unsigned int i; + bitmap_iterator bi; + + if (bitmap_empty_p (b)) + return false; + EXECUTE_IF_SET_IN_BITMAP (b, 1, i, bi) + return true; + return false; +} + +/* Perform offline variable substitution. + + This is a linear time way of identifying variables that must have + equivalent points-to sets, including those caused by static cycles, + and single entry subgraphs, in the constraint graph. + + The technique is described in "Off-line variable substitution for + scaling points-to analysis" by Atanas Rountev and Satish Chandra, + in "ACM SIGPLAN Notices" volume 35, number 5, pages 47-56. */ + +static void +perform_var_substitution (constraint_graph_t graph) +{ + struct topo_info *ti = init_topo_info (); + + bitmap_obstack_initialize (&iteration_obstack); + /* Compute the topological ordering of the graph, then visit each + node in topological order. */ + compute_topo_order (graph, ti); + + while (VEC_length (unsigned, ti->topo_order) != 0) + { + unsigned int i = VEC_pop (unsigned, ti->topo_order); + unsigned int pred; + varinfo_t vi = get_varinfo (i); + bool okay_to_elim = false; + unsigned int root = VEC_length (varinfo_t, varmap); + VEC(constraint_edge_t,heap) *predvec = graph->preds[i]; + constraint_edge_t ce = NULL; + bitmap tmp; + unsigned int k; + bitmap_iterator bi; + + /* We can't eliminate things whose address is taken, or which is + the target of a dereference. */ + if (vi->address_taken || vi->indirect_target) + continue; + + /* See if all predecessors of I are ripe for elimination */ + EXECUTE_IF_IN_NONNULL_BITMAP (graph->zero_weight_preds[i], 0, k, bi) + { + unsigned int w; + w = get_varinfo (k)->node; + + /* We can't eliminate the node if one of the predecessors is + part of a different strongly connected component. */ + if (!okay_to_elim) + { + root = w; + okay_to_elim = true; + } + else if (w != root) + { + okay_to_elim = false; + break; + } + + /* Theorem 4 in Rountev and Chandra: If i is a direct node, + then Solution(i) is a subset of Solution (w), where w is a + predecessor in the graph. + Corollary: If all predecessors of i have the same + points-to set, then i has that same points-to set as + those predecessors. */ + tmp = BITMAP_ALLOC (NULL); + bitmap_and_compl (tmp, get_varinfo (i)->solution, + get_varinfo (w)->solution); + if (!bitmap_empty_p (tmp)) + { + okay_to_elim = false; + BITMAP_FREE (tmp); + break; + } + BITMAP_FREE (tmp); + } + + if (okay_to_elim) + for (pred = 0; + VEC_iterate (constraint_edge_t, predvec, pred, ce); + pred++) + { + bitmap weight; + unsigned int w; + weight = *(get_graph_weights (graph, i, ce->dest)); + + /* We can't eliminate variables that have nonzero weighted + edges between them. */ + if (weight && bitmap_other_than_zero_bit_set (weight)) + { + okay_to_elim = false; + break; + } + w = get_varinfo (ce->dest)->node; + + /* We can't eliminate the node if one of the predecessors is + part of a different strongly connected component. */ + if (!okay_to_elim) + { + root = w; + okay_to_elim = true; + } + else if (w != root) + { + okay_to_elim = false; + break; + } + + /* Theorem 4 in Rountev and Chandra: If i is a direct node, + then Solution(i) is a subset of Solution (w), where w is a + predecessor in the graph. + Corollary: If all predecessors of i have the same + points-to set, then i has that same points-to set as + those predecessors. */ + tmp = BITMAP_ALLOC (NULL); + bitmap_and_compl (tmp, get_varinfo (i)->solution, + get_varinfo (w)->solution); + if (!bitmap_empty_p (tmp)) + { + okay_to_elim = false; + BITMAP_FREE (tmp); + break; + } + BITMAP_FREE (tmp); + } + + /* See if the root is different than the original node. + If so, we've found an equivalence. */ + if (root != get_varinfo (i)->node && okay_to_elim) + { + /* Found an equivalence */ + get_varinfo (i)->node = root; + collapse_nodes (graph, root, i); + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Collapsing %s into %s\n", + get_varinfo (i)->name, + get_varinfo (root)->name); + stats.collapsed_vars++; + } + } + + bitmap_obstack_release (&iteration_obstack); + free_topo_info (ti); +} + +/* Solve the constraint graph GRAPH using our worklist solver. + This is based on the PW* family of solvers from the "Efficient Field + Sensitive Pointer Analysis for C" paper. + It works by iterating over all the graph nodes, processing the complex + constraints and propagating the copy constraints, until everything stops + changed. This corresponds to steps 6-8 in the solving list given above. */ + +static void +solve_graph (constraint_graph_t graph) +{ + unsigned int size = VEC_length (varinfo_t, varmap); + unsigned int i; + + changed_count = size; + changed = sbitmap_alloc (size); + sbitmap_ones (changed); + + /* The already collapsed/unreachable nodes will never change, so we + need to account for them in changed_count. */ + for (i = 0; i < size; i++) + if (get_varinfo (i)->node != i) + changed_count--; + + while (changed_count > 0) + { + unsigned int i; + struct topo_info *ti = init_topo_info (); + stats.iterations++; + + bitmap_obstack_initialize (&iteration_obstack); + + if (edge_added) + { + /* We already did cycle elimination once, when we did + variable substitution, so we don't need it again for the + first iteration. */ + if (stats.iterations > 1) + find_and_collapse_graph_cycles (graph, true); + + edge_added = false; + } + + compute_topo_order (graph, ti); + + while (VEC_length (unsigned, ti->topo_order) != 0) + { + i = VEC_pop (unsigned, ti->topo_order); + gcc_assert (get_varinfo (i)->node == i); + + /* If the node has changed, we need to process the + complex constraints and outgoing edges again. */ + if (TEST_BIT (changed, i)) + { + unsigned int j; + constraint_t c; + constraint_edge_t e = NULL; + bitmap solution; + bitmap_iterator bi; + VEC(constraint_t,heap) *complex = get_varinfo (i)->complex; + VEC(constraint_edge_t,heap) *succs; + bool solution_empty; + + RESET_BIT (changed, i); + changed_count--; + + solution = get_varinfo (i)->solution; + solution_empty = bitmap_empty_p (solution); + + /* Process the complex constraints */ + for (j = 0; VEC_iterate (constraint_t, complex, j, c); j++) + { + /* The only complex constraint that can change our + solution to non-empty, given an empty solution, + is a constraint where the lhs side is receiving + some set from elsewhere. */ + if (!solution_empty || c->lhs.type != DEREF) + do_complex_constraint (graph, c, solution); + } + + solution_empty = bitmap_empty_p (solution); + + if (!solution_empty) + { + /* Propagate solution to all successors. */ + succs = graph->succs[i]; + + EXECUTE_IF_IN_NONNULL_BITMAP (graph->zero_weight_succs[i], + 0, j, bi) + { + bitmap tmp = get_varinfo (j)->solution; + bool flag = false; + + flag = set_union_with_increment (tmp, solution, 0); + + if (flag) + { + get_varinfo (j)->solution = tmp; + if (!TEST_BIT (changed, j)) + { + SET_BIT (changed, j); + changed_count++; + } + } + } + for (j = 0; VEC_iterate (constraint_edge_t, succs, j, e); j++) + { + bitmap tmp = get_varinfo (e->dest)->solution; + bool flag = false; + unsigned int k; + bitmap weights = e->weights; + bitmap_iterator bi; + + gcc_assert (weights && !bitmap_empty_p (weights)); + EXECUTE_IF_SET_IN_BITMAP (weights, 0, k, bi) + flag |= set_union_with_increment (tmp, solution, k); + + if (flag) + { + get_varinfo (e->dest)->solution = tmp; + if (!TEST_BIT (changed, e->dest)) + { + SET_BIT (changed, e->dest); + changed_count++; + } + } + } + } + } + } + free_topo_info (ti); + bitmap_obstack_release (&iteration_obstack); + } + + sbitmap_free (changed); +} + + +/* CONSTRAINT AND VARIABLE GENERATION FUNCTIONS */ + +/* Map from trees to variable ids. */ +static htab_t id_for_tree; + +typedef struct tree_id +{ + tree t; + unsigned int id; +} *tree_id_t; + +/* Hash a tree id structure. */ + +static hashval_t +tree_id_hash (const void *p) +{ + const tree_id_t ta = (tree_id_t) p; + return htab_hash_pointer (ta->t); +} + +/* Return true if the tree in P1 and the tree in P2 are the same. */ + +static int +tree_id_eq (const void *p1, const void *p2) +{ + const tree_id_t ta1 = (tree_id_t) p1; + const tree_id_t ta2 = (tree_id_t) p2; + return ta1->t == ta2->t; +} + +/* Insert ID as the variable id for tree T in the hashtable. */ + +static void +insert_id_for_tree (tree t, int id) +{ + void **slot; + struct tree_id finder; + tree_id_t new_pair; + + finder.t = t; + slot = htab_find_slot (id_for_tree, &finder, INSERT); + gcc_assert (*slot == NULL); + new_pair = XNEW (struct tree_id); + new_pair->t = t; + new_pair->id = id; + *slot = (void *)new_pair; +} + +/* Find the variable id for tree T in ID_FOR_TREE. If T does not + exist in the hash table, return false, otherwise, return true and + set *ID to the id we found. */ + +static bool +lookup_id_for_tree (tree t, unsigned int *id) +{ + tree_id_t pair; + struct tree_id finder; + + finder.t = t; + pair = htab_find (id_for_tree, &finder); + if (pair == NULL) + return false; + *id = pair->id; + return true; +} + +/* Return a printable name for DECL */ + +static const char * +alias_get_name (tree decl) +{ + const char *res = get_name (decl); + char *temp; + int num_printed = 0; + + if (res != NULL) + return res; + + res = "NULL"; + if (!dump_file) + return res; + + if (TREE_CODE (decl) == SSA_NAME) + { + num_printed = asprintf (&temp, "%s_%u", + alias_get_name (SSA_NAME_VAR (decl)), + SSA_NAME_VERSION (decl)); + } + else if (DECL_P (decl)) + { + num_printed = asprintf (&temp, "D.%u", DECL_UID (decl)); + } + if (num_printed > 0) + { + res = ggc_strdup (temp); + free (temp); + } + return res; +} + +/* Find the variable id for tree T in the hashtable. + If T doesn't exist in the hash table, create an entry for it. */ + +static unsigned int +get_id_for_tree (tree t) +{ + tree_id_t pair; + struct tree_id finder; + + finder.t = t; + pair = htab_find (id_for_tree, &finder); + if (pair == NULL) + return create_variable_info_for (t, alias_get_name (t)); + + return pair->id; +} + +/* Get a constraint expression from an SSA_VAR_P node. */ + +static struct constraint_expr +get_constraint_exp_from_ssa_var (tree t) +{ + struct constraint_expr cexpr; + + gcc_assert (SSA_VAR_P (t) || DECL_P (t)); + + /* For parameters, get at the points-to set for the actual parm + decl. */ + if (TREE_CODE (t) == SSA_NAME + && TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL + && default_def (SSA_NAME_VAR (t)) == t) + return get_constraint_exp_from_ssa_var (SSA_NAME_VAR (t)); + + cexpr.type = SCALAR; + + cexpr.var = get_id_for_tree (t); + /* If we determine the result is "anything", and we know this is readonly, + say it points to readonly memory instead. */ + if (cexpr.var == anything_id && TREE_READONLY (t)) + { + cexpr.type = ADDRESSOF; + cexpr.var = readonly_id; + } + + cexpr.offset = 0; + return cexpr; +} + +/* Process a completed constraint T, and add it to the constraint + list. */ + +static void +process_constraint (constraint_t t) +{ + struct constraint_expr rhs = t->rhs; + struct constraint_expr lhs = t->lhs; + + gcc_assert (rhs.var < VEC_length (varinfo_t, varmap)); + gcc_assert (lhs.var < VEC_length (varinfo_t, varmap)); + + if (lhs.type == DEREF) + get_varinfo (lhs.var)->directly_dereferenced = true; + if (rhs.type == DEREF) + get_varinfo (rhs.var)->directly_dereferenced = true; + + /* ANYTHING == ANYTHING is pointless. */ + if (lhs.var == anything_id && rhs.var == anything_id) + return; + + /* If we have &ANYTHING = something, convert to SOMETHING = &ANYTHING) */ + else if (lhs.var == anything_id && lhs.type == ADDRESSOF) + { + rhs = t->lhs; + t->lhs = t->rhs; + t->rhs = rhs; + process_constraint (t); + } + /* This can happen in our IR with things like n->a = *p */ + else if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id) + { + /* Split into tmp = *rhs, *lhs = tmp */ + tree rhsdecl = get_varinfo (rhs.var)->decl; + tree pointertype = TREE_TYPE (rhsdecl); + tree pointedtotype = TREE_TYPE (pointertype); + tree tmpvar = create_tmp_var_raw (pointedtotype, "doubledereftmp"); + struct constraint_expr tmplhs = get_constraint_exp_from_ssa_var (tmpvar); + + /* If this is an aggregate of known size, we should have passed + this off to do_structure_copy, and it should have broken it + up. */ + gcc_assert (!AGGREGATE_TYPE_P (pointedtotype) + || get_varinfo (rhs.var)->is_unknown_size_var); + + process_constraint (new_constraint (tmplhs, rhs)); + process_constraint (new_constraint (lhs, tmplhs)); + } + else if (rhs.type == ADDRESSOF) + { + varinfo_t vi; + gcc_assert (rhs.offset == 0); + + /* No need to mark address taken simply because of escaped vars + constraints. */ + if (lhs.var != escaped_vars_id) + for (vi = get_varinfo (rhs.var); vi != NULL; vi = vi->next) + vi->address_taken = true; + + VEC_safe_push (constraint_t, heap, constraints, t); + } + else + { + if (lhs.type != DEREF && rhs.type == DEREF) + get_varinfo (lhs.var)->indirect_target = true; + VEC_safe_push (constraint_t, heap, constraints, t); + } +} + +/* Return true if T is a variable of a type that could contain + pointers. */ + +static bool +could_have_pointers (tree t) +{ + tree type = TREE_TYPE (t); + + if (POINTER_TYPE_P (type) || AGGREGATE_TYPE_P (type) + || TREE_CODE (type) == COMPLEX_TYPE) + return true; + return false; +} + +/* Return the position, in bits, of FIELD_DECL from the beginning of its + structure. */ + +static unsigned HOST_WIDE_INT +bitpos_of_field (const tree fdecl) +{ + + if (TREE_CODE (DECL_FIELD_OFFSET (fdecl)) != INTEGER_CST + || TREE_CODE (DECL_FIELD_BIT_OFFSET (fdecl)) != INTEGER_CST) + return -1; + + return (tree_low_cst (DECL_FIELD_OFFSET (fdecl), 1) * 8) + + tree_low_cst (DECL_FIELD_BIT_OFFSET (fdecl), 1); +} + + +/* Return true if an access to [ACCESSPOS, ACCESSSIZE] + overlaps with a field at [FIELDPOS, FIELDSIZE] */ + +static bool +offset_overlaps_with_access (const unsigned HOST_WIDE_INT fieldpos, + const unsigned HOST_WIDE_INT fieldsize, + const unsigned HOST_WIDE_INT accesspos, + const unsigned HOST_WIDE_INT accesssize) +{ + if (fieldpos == accesspos && fieldsize == accesssize) + return true; + if (accesspos >= fieldpos && accesspos < (fieldpos + fieldsize)) + return true; + if (accesspos < fieldpos && (accesspos + accesssize > fieldpos)) + return true; + + return false; +} + +/* Given a COMPONENT_REF T, return the constraint_expr for it. */ + +static void +get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results) +{ + tree orig_t = t; + HOST_WIDE_INT bitsize = -1; + HOST_WIDE_INT bitmaxsize = -1; + HOST_WIDE_INT bitpos; + tree forzero; + struct constraint_expr *result; + unsigned int beforelength = VEC_length (ce_s, *results); + + /* Some people like to do cute things like take the address of + &0->a.b */ + forzero = t; + while (!SSA_VAR_P (forzero) && !CONSTANT_CLASS_P (forzero)) + forzero = TREE_OPERAND (forzero, 0); + + if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero)) + { + struct constraint_expr temp; + + temp.offset = 0; + temp.var = integer_id; + temp.type = SCALAR; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + + t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize); + + /* String constants's are readonly, so there is nothing to really do + here. */ + if (TREE_CODE (t) == STRING_CST) + return; + + get_constraint_for (t, results); + result = VEC_last (ce_s, *results); + result->offset = bitpos; + + gcc_assert (beforelength + 1 == VEC_length (ce_s, *results)); + + /* This can also happen due to weird offsetof type macros. */ + if (TREE_CODE (t) != ADDR_EXPR && result->type == ADDRESSOF) + result->type = SCALAR; + + if (result->type == SCALAR) + { + /* In languages like C, you can access one past the end of an + array. You aren't allowed to dereference it, so we can + ignore this constraint. When we handle pointer subtraction, + we may have to do something cute here. */ + + if (result->offset < get_varinfo (result->var)->fullsize + && bitmaxsize != 0) + { + /* It's also not true that the constraint will actually start at the + right offset, it may start in some padding. We only care about + setting the constraint to the first actual field it touches, so + walk to find it. */ + varinfo_t curr; + for (curr = get_varinfo (result->var); curr; curr = curr->next) + { + if (offset_overlaps_with_access (curr->offset, curr->size, + result->offset, bitmaxsize)) + { + result->var = curr->id; + break; + } + } + /* assert that we found *some* field there. The user couldn't be + accessing *only* padding. */ + /* Still the user could access one past the end of an array + embedded in a struct resulting in accessing *only* padding. */ + gcc_assert (curr || ref_contains_array_ref (orig_t)); + } + else if (bitmaxsize == 0) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Access to zero-sized part of variable," + "ignoring\n"); + } + else + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Access to past the end of variable, ignoring\n"); + + result->offset = 0; + } +} + + +/* Dereference the constraint expression CONS, and return the result. + DEREF (ADDRESSOF) = SCALAR + DEREF (SCALAR) = DEREF + DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp)) + This is needed so that we can handle dereferencing DEREF constraints. */ + +static void +do_deref (VEC (ce_s, heap) **constraints) +{ + struct constraint_expr *c; + unsigned int i = 0; + for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++) + { + if (c->type == SCALAR) + c->type = DEREF; + else if (c->type == ADDRESSOF) + c->type = SCALAR; + else if (c->type == DEREF) + { + tree tmpvar = create_tmp_var_raw (ptr_type_node, "dereftmp"); + struct constraint_expr tmplhs = get_constraint_exp_from_ssa_var (tmpvar); + process_constraint (new_constraint (tmplhs, *c)); + c->var = tmplhs.var; + } + else + gcc_unreachable (); + } +} + +/* Create a nonlocal variable of TYPE to represent nonlocals we can + alias. */ + +static tree +create_nonlocal_var (tree type) +{ + tree nonlocal = create_tmp_var_raw (type, "NONLOCAL"); + + if (referenced_vars) + add_referenced_var (nonlocal); + + DECL_EXTERNAL (nonlocal) = 1; + return nonlocal; +} + +/* Given a tree T, return the constraint expression for it. */ + +static void +get_constraint_for (tree t, VEC (ce_s, heap) **results) +{ + struct constraint_expr temp; + + /* x = integer is all glommed to a single variable, which doesn't + point to anything by itself. That is, of course, unless it is an + integer constant being treated as a pointer, in which case, we + will return that this is really the addressof anything. This + happens below, since it will fall into the default case. The only + case we know something about an integer treated like a pointer is + when it is the NULL pointer, and then we just say it points to + NULL. */ + if (TREE_CODE (t) == INTEGER_CST + && !POINTER_TYPE_P (TREE_TYPE (t))) + { + temp.var = integer_id; + temp.type = SCALAR; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + else if (TREE_CODE (t) == INTEGER_CST + && integer_zerop (t)) + { + temp.var = nothing_id; + temp.type = ADDRESSOF; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + + switch (TREE_CODE_CLASS (TREE_CODE (t))) + { + case tcc_expression: + { + switch (TREE_CODE (t)) + { + case ADDR_EXPR: + { + struct constraint_expr *c; + unsigned int i; + tree exp = TREE_OPERAND (t, 0); + tree pttype = TREE_TYPE (TREE_TYPE (t)); + + get_constraint_for (exp, results); + /* Make sure we capture constraints to all elements + of an array. */ + if ((handled_component_p (exp) + && ref_contains_array_ref (exp)) + || TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE) + { + struct constraint_expr *origrhs; + varinfo_t origvar; + struct constraint_expr tmp; + + if (VEC_length (ce_s, *results) == 0) + return; + + gcc_assert (VEC_length (ce_s, *results) == 1); + origrhs = VEC_last (ce_s, *results); + tmp = *origrhs; + VEC_pop (ce_s, *results); + origvar = get_varinfo (origrhs->var); + for (; origvar; origvar = origvar->next) + { + tmp.var = origvar->id; + VEC_safe_push (ce_s, heap, *results, &tmp); + } + } + else if (VEC_length (ce_s, *results) == 1 + && (AGGREGATE_TYPE_P (pttype) + || TREE_CODE (pttype) == COMPLEX_TYPE)) + { + struct constraint_expr *origrhs; + varinfo_t origvar; + struct constraint_expr tmp; + + gcc_assert (VEC_length (ce_s, *results) == 1); + origrhs = VEC_last (ce_s, *results); + tmp = *origrhs; + VEC_pop (ce_s, *results); + origvar = get_varinfo (origrhs->var); + for (; origvar; origvar = origvar->next) + { + tmp.var = origvar->id; + VEC_safe_push (ce_s, heap, *results, &tmp); + } + } + + for (i = 0; VEC_iterate (ce_s, *results, i, c); i++) + { + if (c->type == DEREF) + c->type = SCALAR; + else + c->type = ADDRESSOF; + } + return; + } + break; + case CALL_EXPR: + /* XXX: In interprocedural mode, if we didn't have the + body, we would need to do *each pointer argument = + &ANYTHING added. */ + if (call_expr_flags (t) & (ECF_MALLOC | ECF_MAY_BE_ALLOCA)) + { + varinfo_t vi; + tree heapvar = heapvar_lookup (t); + + if (heapvar == NULL) + { + heapvar = create_tmp_var_raw (ptr_type_node, "HEAP"); + DECL_EXTERNAL (heapvar) = 1; + if (referenced_vars) + add_referenced_var (heapvar); + heapvar_insert (t, heapvar); + } + + temp.var = create_variable_info_for (heapvar, + alias_get_name (heapvar)); + + vi = get_varinfo (temp.var); + vi->is_artificial_var = 1; + vi->is_heap_var = 1; + temp.type = ADDRESSOF; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + else + { + temp.var = escaped_vars_id; + temp.type = SCALAR; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + break; + default: + { + temp.type = ADDRESSOF; + temp.var = anything_id; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + } + } + case tcc_reference: + { + switch (TREE_CODE (t)) + { + case INDIRECT_REF: + { + get_constraint_for (TREE_OPERAND (t, 0), results); + do_deref (results); + return; + } + case ARRAY_REF: + case ARRAY_RANGE_REF: + case COMPONENT_REF: + get_constraint_for_component_ref (t, results); + return; + default: + { + temp.type = ADDRESSOF; + temp.var = anything_id; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + } + } + case tcc_unary: + { + switch (TREE_CODE (t)) + { + case NOP_EXPR: + case CONVERT_EXPR: + case NON_LVALUE_EXPR: + { + tree op = TREE_OPERAND (t, 0); + + /* Cast from non-pointer to pointers are bad news for us. + Anything else, we see through */ + if (!(POINTER_TYPE_P (TREE_TYPE (t)) + && ! POINTER_TYPE_P (TREE_TYPE (op)))) + { + get_constraint_for (op, results); + return; + } + + /* FALLTHRU */ + } + default: + { + temp.type = ADDRESSOF; + temp.var = anything_id; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + } + } + case tcc_exceptional: + { + switch (TREE_CODE (t)) + { + case PHI_NODE: + { + get_constraint_for (PHI_RESULT (t), results); + return; + } + break; + case SSA_NAME: + { + struct constraint_expr temp; + temp = get_constraint_exp_from_ssa_var (t); + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + break; + default: + { + temp.type = ADDRESSOF; + temp.var = anything_id; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + } + } + case tcc_declaration: + { + struct constraint_expr temp; + temp = get_constraint_exp_from_ssa_var (t); + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + default: + { + temp.type = ADDRESSOF; + temp.var = anything_id; + temp.offset = 0; + VEC_safe_push (ce_s, heap, *results, &temp); + return; + } + } +} + + +/* Handle the structure copy case where we have a simple structure copy + between LHS and RHS that is of SIZE (in bits) + + For each field of the lhs variable (lhsfield) + For each field of the rhs variable at lhsfield.offset (rhsfield) + add the constraint lhsfield = rhsfield + + If we fail due to some kind of type unsafety or other thing we + can't handle, return false. We expect the caller to collapse the + variable in that case. */ + +static bool +do_simple_structure_copy (const struct constraint_expr lhs, + const struct constraint_expr rhs, + const unsigned HOST_WIDE_INT size) +{ + varinfo_t p = get_varinfo (lhs.var); + unsigned HOST_WIDE_INT pstart, last; + pstart = p->offset; + last = p->offset + size; + for (; p && p->offset < last; p = p->next) + { + varinfo_t q; + struct constraint_expr templhs = lhs; + struct constraint_expr temprhs = rhs; + unsigned HOST_WIDE_INT fieldoffset; + + templhs.var = p->id; + q = get_varinfo (temprhs.var); + fieldoffset = p->offset - pstart; + q = first_vi_for_offset (q, q->offset + fieldoffset); + if (!q) + return false; + temprhs.var = q->id; + process_constraint (new_constraint (templhs, temprhs)); + } + return true; +} + + +/* Handle the structure copy case where we have a structure copy between a + aggregate on the LHS and a dereference of a pointer on the RHS + that is of SIZE (in bits) + + For each field of the lhs variable (lhsfield) + rhs.offset = lhsfield->offset + add the constraint lhsfield = rhs +*/ + +static void +do_rhs_deref_structure_copy (const struct constraint_expr lhs, + const struct constraint_expr rhs, + const unsigned HOST_WIDE_INT size) +{ + varinfo_t p = get_varinfo (lhs.var); + unsigned HOST_WIDE_INT pstart,last; + pstart = p->offset; + last = p->offset + size; + + for (; p && p->offset < last; p = p->next) + { + varinfo_t q; + struct constraint_expr templhs = lhs; + struct constraint_expr temprhs = rhs; + unsigned HOST_WIDE_INT fieldoffset; + + + if (templhs.type == SCALAR) + templhs.var = p->id; + else + templhs.offset = p->offset; + + q = get_varinfo (temprhs.var); + fieldoffset = p->offset - pstart; + temprhs.offset += fieldoffset; + process_constraint (new_constraint (templhs, temprhs)); + } +} + +/* Handle the structure copy case where we have a structure copy + between a aggregate on the RHS and a dereference of a pointer on + the LHS that is of SIZE (in bits) + + For each field of the rhs variable (rhsfield) + lhs.offset = rhsfield->offset + add the constraint lhs = rhsfield +*/ + +static void +do_lhs_deref_structure_copy (const struct constraint_expr lhs, + const struct constraint_expr rhs, + const unsigned HOST_WIDE_INT size) +{ + varinfo_t p = get_varinfo (rhs.var); + unsigned HOST_WIDE_INT pstart,last; + pstart = p->offset; + last = p->offset + size; + + for (; p && p->offset < last; p = p->next) + { + varinfo_t q; + struct constraint_expr templhs = lhs; + struct constraint_expr temprhs = rhs; + unsigned HOST_WIDE_INT fieldoffset; + + + if (temprhs.type == SCALAR) + temprhs.var = p->id; + else + temprhs.offset = p->offset; + + q = get_varinfo (templhs.var); + fieldoffset = p->offset - pstart; + templhs.offset += fieldoffset; + process_constraint (new_constraint (templhs, temprhs)); + } +} + +/* Sometimes, frontends like to give us bad type information. This + function will collapse all the fields from VAR to the end of VAR, + into VAR, so that we treat those fields as a single variable. + We return the variable they were collapsed into. */ + +static unsigned int +collapse_rest_of_var (unsigned int var) +{ + varinfo_t currvar = get_varinfo (var); + varinfo_t field; + + for (field = currvar->next; field; field = field->next) + { + if (dump_file) + fprintf (dump_file, "Type safety: Collapsing var %s into %s\n", + field->name, currvar->name); + + gcc_assert (!field->collapsed_to); + field->collapsed_to = currvar; + } + + currvar->next = NULL; + currvar->size = currvar->fullsize - currvar->offset; + + return currvar->id; +} + +/* Handle aggregate copies by expanding into copies of the respective + fields of the structures. */ + +static void +do_structure_copy (tree lhsop, tree rhsop) +{ + struct constraint_expr lhs, rhs, tmp; + VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL; + varinfo_t p; + unsigned HOST_WIDE_INT lhssize; + unsigned HOST_WIDE_INT rhssize; + + get_constraint_for (lhsop, &lhsc); + get_constraint_for (rhsop, &rhsc); + gcc_assert (VEC_length (ce_s, lhsc) == 1); + gcc_assert (VEC_length (ce_s, rhsc) == 1); + lhs = *(VEC_last (ce_s, lhsc)); + rhs = *(VEC_last (ce_s, rhsc)); + + VEC_free (ce_s, heap, lhsc); + VEC_free (ce_s, heap, rhsc); + + /* If we have special var = x, swap it around. */ + if (lhs.var <= integer_id && !(get_varinfo (rhs.var)->is_special_var)) + { + tmp = lhs; + lhs = rhs; + rhs = tmp; + } + + /* This is fairly conservative for the RHS == ADDRESSOF case, in that it's + possible it's something we could handle. However, most cases falling + into this are dealing with transparent unions, which are slightly + weird. */ + if (rhs.type == ADDRESSOF && !(get_varinfo (rhs.var)->is_special_var)) + { + rhs.type = ADDRESSOF; + rhs.var = anything_id; + } + + /* If the RHS is a special var, or an addressof, set all the LHS fields to + that special var. */ + if (rhs.var <= integer_id) + { + for (p = get_varinfo (lhs.var); p; p = p->next) + { + struct constraint_expr templhs = lhs; + struct constraint_expr temprhs = rhs; + + if (templhs.type == SCALAR ) + templhs.var = p->id; + else + templhs.offset += p->offset; + process_constraint (new_constraint (templhs, temprhs)); + } + } + else + { + tree rhstype = TREE_TYPE (rhsop); + tree lhstype = TREE_TYPE (lhsop); + tree rhstypesize; + tree lhstypesize; + + lhstypesize = DECL_P (lhsop) ? DECL_SIZE (lhsop) : TYPE_SIZE (lhstype); + rhstypesize = DECL_P (rhsop) ? DECL_SIZE (rhsop) : TYPE_SIZE (rhstype); + + /* If we have a variably sized types on the rhs or lhs, and a deref + constraint, add the constraint, lhsconstraint = &ANYTHING. + This is conservatively correct because either the lhs is an unknown + sized var (if the constraint is SCALAR), or the lhs is a DEREF + constraint, and every variable it can point to must be unknown sized + anyway, so we don't need to worry about fields at all. */ + if ((rhs.type == DEREF && TREE_CODE (rhstypesize) != INTEGER_CST) + || (lhs.type == DEREF && TREE_CODE (lhstypesize) != INTEGER_CST)) + { + rhs.var = anything_id; + rhs.type = ADDRESSOF; + rhs.offset = 0; + process_constraint (new_constraint (lhs, rhs)); + return; + } + + /* The size only really matters insofar as we don't set more or less of + the variable. If we hit an unknown size var, the size should be the + whole darn thing. */ + if (get_varinfo (rhs.var)->is_unknown_size_var) + rhssize = ~0; + else + rhssize = TREE_INT_CST_LOW (rhstypesize); + + if (get_varinfo (lhs.var)->is_unknown_size_var) + lhssize = ~0; + else + lhssize = TREE_INT_CST_LOW (lhstypesize); + + + if (rhs.type == SCALAR && lhs.type == SCALAR) + { + if (!do_simple_structure_copy (lhs, rhs, MIN (lhssize, rhssize))) + { + lhs.var = collapse_rest_of_var (lhs.var); + rhs.var = collapse_rest_of_var (rhs.var); + lhs.offset = 0; + rhs.offset = 0; + lhs.type = SCALAR; + rhs.type = SCALAR; + process_constraint (new_constraint (lhs, rhs)); + } + } + else if (lhs.type != DEREF && rhs.type == DEREF) + do_rhs_deref_structure_copy (lhs, rhs, MIN (lhssize, rhssize)); + else if (lhs.type == DEREF && rhs.type != DEREF) + do_lhs_deref_structure_copy (lhs, rhs, MIN (lhssize, rhssize)); + else + { + tree pointedtotype = lhstype; + tree tmpvar; + + gcc_assert (rhs.type == DEREF && lhs.type == DEREF); + tmpvar = create_tmp_var_raw (pointedtotype, "structcopydereftmp"); + do_structure_copy (tmpvar, rhsop); + do_structure_copy (lhsop, tmpvar); + } + } +} + +/* Update related alias information kept in AI. This is used when + building name tags, alias sets and deciding grouping heuristics. + STMT is the statement to process. This function also updates + ADDRESSABLE_VARS. */ + +static void +update_alias_info (tree stmt, struct alias_info *ai) +{ + bitmap addr_taken; + use_operand_p use_p; + ssa_op_iter iter; + enum escape_type stmt_escape_type = is_escape_site (stmt); + tree op; + + if (stmt_escape_type == ESCAPE_TO_CALL + || stmt_escape_type == ESCAPE_TO_PURE_CONST) + { + ai->num_calls_found++; + if (stmt_escape_type == ESCAPE_TO_PURE_CONST) + ai->num_pure_const_calls_found++; + } + + /* Mark all the variables whose address are taken by the statement. */ + addr_taken = addresses_taken (stmt); + if (addr_taken) + { + bitmap_ior_into (addressable_vars, addr_taken); + + /* If STMT is an escape point, all the addresses taken by it are + call-clobbered. */ + if (stmt_escape_type != NO_ESCAPE) + { + bitmap_iterator bi; + unsigned i; + + EXECUTE_IF_SET_IN_BITMAP (addr_taken, 0, i, bi) + { + tree rvar = referenced_var (i); + if (!unmodifiable_var_p (rvar)) + mark_call_clobbered (rvar, stmt_escape_type); + } + } + } + + /* Process each operand use. If an operand may be aliased, keep + track of how many times it's being used. For pointers, determine + whether they are dereferenced by the statement, or whether their + value escapes, etc. */ + FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE) + { + tree op, var; + var_ann_t v_ann; + struct ptr_info_def *pi; + bool is_store, is_potential_deref; + unsigned num_uses, num_derefs; + + op = USE_FROM_PTR (use_p); + + /* If STMT is a PHI node, OP may be an ADDR_EXPR. If so, add it + to the set of addressable variables. */ + if (TREE_CODE (op) == ADDR_EXPR) + { + gcc_assert (TREE_CODE (stmt) == PHI_NODE); + + /* PHI nodes don't have annotations for pinning the set + of addresses taken, so we collect them here. + + FIXME, should we allow PHI nodes to have annotations + so that they can be treated like regular statements? + Currently, they are treated as second-class + statements. */ + add_to_addressable_set (TREE_OPERAND (op, 0), &addressable_vars); + continue; + } + + /* Ignore constants. */ + if (TREE_CODE (op) != SSA_NAME) + continue; + + var = SSA_NAME_VAR (op); + v_ann = var_ann (var); + + /* The base variable of an ssa name must be a GIMPLE register, and thus + it cannot be aliased. */ + gcc_assert (!may_be_aliased (var)); + + /* We are only interested in pointers. */ + if (!POINTER_TYPE_P (TREE_TYPE (op))) + continue; + + pi = get_ptr_info (op); + + /* Add OP to AI->PROCESSED_PTRS, if it's not there already. */ + if (!TEST_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op))) + { + SET_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op)); + VEC_safe_push (tree, heap, ai->processed_ptrs, op); + } + + /* If STMT is a PHI node, then it will not have pointer + dereferences and it will not be an escape point. */ + if (TREE_CODE (stmt) == PHI_NODE) + continue; + + /* Determine whether OP is a dereferenced pointer, and if STMT + is an escape point, whether OP escapes. */ + count_uses_and_derefs (op, stmt, &num_uses, &num_derefs, &is_store); + + /* Handle a corner case involving address expressions of the + form '&PTR->FLD'. The problem with these expressions is that + they do not represent a dereference of PTR. However, if some + other transformation propagates them into an INDIRECT_REF + expression, we end up with '*(&PTR->FLD)' which is folded + into 'PTR->FLD'. + + So, if the original code had no other dereferences of PTR, + the aliaser will not create memory tags for it, and when + &PTR->FLD gets propagated to INDIRECT_REF expressions, the + memory operations will receive no V_MAY_DEF/VUSE operands. + + One solution would be to have count_uses_and_derefs consider + &PTR->FLD a dereference of PTR. But that is wrong, since it + is not really a dereference but an offset calculation. + + What we do here is to recognize these special ADDR_EXPR + nodes. Since these expressions are never GIMPLE values (they + are not GIMPLE invariants), they can only appear on the RHS + of an assignment and their base address is always an + INDIRECT_REF expression. */ + is_potential_deref = false; + if (TREE_CODE (stmt) == MODIFY_EXPR + && TREE_CODE (TREE_OPERAND (stmt, 1)) == ADDR_EXPR + && !is_gimple_val (TREE_OPERAND (stmt, 1))) + { + /* If the RHS if of the form &PTR->FLD and PTR == OP, then + this represents a potential dereference of PTR. */ + tree rhs = TREE_OPERAND (stmt, 1); + tree base = get_base_address (TREE_OPERAND (rhs, 0)); + if (TREE_CODE (base) == INDIRECT_REF + && TREE_OPERAND (base, 0) == op) + is_potential_deref = true; + } + + if (num_derefs > 0 || is_potential_deref) + { + /* Mark OP as dereferenced. In a subsequent pass, + dereferenced pointers that point to a set of + variables will be assigned a name tag to alias + all the variables OP points to. */ + pi->is_dereferenced = 1; + + /* Keep track of how many time we've dereferenced each + pointer. */ + NUM_REFERENCES_INC (v_ann); + + /* If this is a store operation, mark OP as being + dereferenced to store, otherwise mark it as being + dereferenced to load. */ + if (is_store) + bitmap_set_bit (ai->dereferenced_ptrs_store, DECL_UID (var)); + else + bitmap_set_bit (ai->dereferenced_ptrs_load, DECL_UID (var)); + } + + if (stmt_escape_type != NO_ESCAPE && num_derefs < num_uses) + { + /* If STMT is an escape point and STMT contains at + least one direct use of OP, then the value of OP + escapes and so the pointed-to variables need to + be marked call-clobbered. */ + pi->value_escapes_p = 1; + pi->escape_mask |= stmt_escape_type; + + /* If the statement makes a function call, assume + that pointer OP will be dereferenced in a store + operation inside the called function. */ + if (get_call_expr_in (stmt) + || stmt_escape_type == ESCAPE_STORED_IN_GLOBAL) + { + bitmap_set_bit (ai->dereferenced_ptrs_store, DECL_UID (var)); + pi->is_dereferenced = 1; + } + } + } + + if (TREE_CODE (stmt) == PHI_NODE) + return; + + /* Update reference counter for definitions to any + potentially aliased variable. This is used in the alias + grouping heuristics. */ + FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF) + { + tree var = SSA_NAME_VAR (op); + var_ann_t ann = var_ann (var); + bitmap_set_bit (ai->written_vars, DECL_UID (var)); + if (may_be_aliased (var)) + NUM_REFERENCES_INC (ann); + + } + + /* Mark variables in V_MAY_DEF operands as being written to. */ + FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_DEFS) + { + tree var = DECL_P (op) ? op : SSA_NAME_VAR (op); + bitmap_set_bit (ai->written_vars, DECL_UID (var)); + } +} + + +/* Handle pointer arithmetic EXPR when creating aliasing constraints. + Expressions of the type PTR + CST can be handled in two ways: + + 1- If the constraint for PTR is ADDRESSOF for a non-structure + variable, then we can use it directly because adding or + subtracting a constant may not alter the original ADDRESSOF + constraint (i.e., pointer arithmetic may not legally go outside + an object's boundaries). + + 2- If the constraint for PTR is ADDRESSOF for a structure variable, + then if CST is a compile-time constant that can be used as an + offset, we can determine which sub-variable will be pointed-to + by the expression. + + Return true if the expression is handled. For any other kind of + expression, return false so that each operand can be added as a + separate constraint by the caller. */ + +static bool +handle_ptr_arith (VEC (ce_s, heap) *lhsc, tree expr) +{ + tree op0, op1; + struct constraint_expr *c, *c2; + unsigned int i = 0; + unsigned int j = 0; + VEC (ce_s, heap) *temp = NULL; + unsigned int rhsoffset = 0; + + if (TREE_CODE (expr) != PLUS_EXPR + && TREE_CODE (expr) != MINUS_EXPR) + return false; + + op0 = TREE_OPERAND (expr, 0); + op1 = TREE_OPERAND (expr, 1); + + get_constraint_for (op0, &temp); + if (POINTER_TYPE_P (TREE_TYPE (op0)) + && TREE_CODE (op1) == INTEGER_CST + && TREE_CODE (expr) == PLUS_EXPR) + { + rhsoffset = TREE_INT_CST_LOW (op1) * BITS_PER_UNIT; + } + else + return false; + + for (i = 0; VEC_iterate (ce_s, lhsc, i, c); i++) + for (j = 0; VEC_iterate (ce_s, temp, j, c2); j++) + { + if (c2->type == ADDRESSOF && rhsoffset != 0) + { + varinfo_t temp = get_varinfo (c2->var); + + /* An access one after the end of an array is valid, + so simply punt on accesses we cannot resolve. */ + temp = first_vi_for_offset (temp, rhsoffset); + if (temp == NULL) + continue; + c2->var = temp->id; + c2->offset = 0; + } + else + c2->offset = rhsoffset; + process_constraint (new_constraint (*c, *c2)); + } + + VEC_free (ce_s, heap, temp); + + return true; +} + + +/* Walk statement T setting up aliasing constraints according to the + references found in T. This function is the main part of the + constraint builder. AI points to auxiliary alias information used + when building alias sets and computing alias grouping heuristics. */ + +static void +find_func_aliases (tree origt) +{ + tree t = origt; + VEC(ce_s, heap) *lhsc = NULL; + VEC(ce_s, heap) *rhsc = NULL; + struct constraint_expr *c; + + if (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)) + t = TREE_OPERAND (t, 0); + + /* Now build constraints expressions. */ + if (TREE_CODE (t) == PHI_NODE) + { + gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (PHI_RESULT (t)))); + + /* Only care about pointers and structures containing + pointers. */ + if (could_have_pointers (PHI_RESULT (t))) + { + int i; + unsigned int j; + + /* For a phi node, assign all the arguments to + the result. */ + get_constraint_for (PHI_RESULT (t), &lhsc); + for (i = 0; i < PHI_NUM_ARGS (t); i++) + { + tree rhstype; + tree strippedrhs = PHI_ARG_DEF (t, i); + + STRIP_NOPS (strippedrhs); + rhstype = TREE_TYPE (strippedrhs); + get_constraint_for (PHI_ARG_DEF (t, i), &rhsc); + + for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++) + { + struct constraint_expr *c2; + while (VEC_length (ce_s, rhsc) > 0) + { + c2 = VEC_last (ce_s, rhsc); + process_constraint (new_constraint (*c, *c2)); + VEC_pop (ce_s, rhsc); + } + } + } + } + } + /* In IPA mode, we need to generate constraints to pass call + arguments through their calls. There are two case, either a + modify_expr when we are returning a value, or just a plain + call_expr when we are not. */ + else if (in_ipa_mode + && ((TREE_CODE (t) == MODIFY_EXPR + && TREE_CODE (TREE_OPERAND (t, 1)) == CALL_EXPR + && !(call_expr_flags (TREE_OPERAND (t, 1)) + & (ECF_MALLOC | ECF_MAY_BE_ALLOCA))) + || (TREE_CODE (t) == CALL_EXPR + && !(call_expr_flags (t) + & (ECF_MALLOC | ECF_MAY_BE_ALLOCA))))) + { + tree lhsop; + tree rhsop; + unsigned int varid; + tree arglist; + varinfo_t fi; + int i = 1; + tree decl; + if (TREE_CODE (t) == MODIFY_EXPR) + { + lhsop = TREE_OPERAND (t, 0); + rhsop = TREE_OPERAND (t, 1); + } + else + { + lhsop = NULL; + rhsop = t; + } + decl = get_callee_fndecl (rhsop); + + /* If we can directly resolve the function being called, do so. + Otherwise, it must be some sort of indirect expression that + we should still be able to handle. */ + if (decl) + { + varid = get_id_for_tree (decl); + } + else + { + decl = TREE_OPERAND (rhsop, 0); + varid = get_id_for_tree (decl); + } + + /* Assign all the passed arguments to the appropriate incoming + parameters of the function. */ + fi = get_varinfo (varid); + arglist = TREE_OPERAND (rhsop, 1); + + for (;arglist; arglist = TREE_CHAIN (arglist)) + { + tree arg = TREE_VALUE (arglist); + struct constraint_expr lhs ; + struct constraint_expr *rhsp; + + get_constraint_for (arg, &rhsc); + if (TREE_CODE (decl) != FUNCTION_DECL) + { + lhs.type = DEREF; + lhs.var = fi->id; + lhs.offset = i; + } + else + { + lhs.type = SCALAR; + lhs.var = first_vi_for_offset (fi, i)->id; + lhs.offset = 0; + } + while (VEC_length (ce_s, rhsc) != 0) + { + rhsp = VEC_last (ce_s, rhsc); + process_constraint (new_constraint (lhs, *rhsp)); + VEC_pop (ce_s, rhsc); + } + i++; + } + /* If we are returning a value, assign it to the result. */ + if (lhsop) + { + struct constraint_expr rhs; + struct constraint_expr *lhsp; + unsigned int j = 0; + + get_constraint_for (lhsop, &lhsc); + if (TREE_CODE (decl) != FUNCTION_DECL) + { + rhs.type = DEREF; + rhs.var = fi->id; + rhs.offset = i; + } + else + { + rhs.type = SCALAR; + rhs.var = first_vi_for_offset (fi, i)->id; + rhs.offset = 0; + } + for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++) + process_constraint (new_constraint (*lhsp, rhs)); + } + } + /* Otherwise, just a regular assignment statement. */ + else if (TREE_CODE (t) == MODIFY_EXPR) + { + tree lhsop = TREE_OPERAND (t, 0); + tree rhsop = TREE_OPERAND (t, 1); + int i; + + if ((AGGREGATE_TYPE_P (TREE_TYPE (lhsop)) + || TREE_CODE (TREE_TYPE (lhsop)) == COMPLEX_TYPE) + && (AGGREGATE_TYPE_P (TREE_TYPE (rhsop)) + || TREE_CODE (TREE_TYPE (lhsop)) == COMPLEX_TYPE)) + { + do_structure_copy (lhsop, rhsop); + } + else + { + /* Only care about operations with pointers, structures + containing pointers, dereferences, and call expressions. */ + if (could_have_pointers (lhsop) + || TREE_CODE (rhsop) == CALL_EXPR) + { + get_constraint_for (lhsop, &lhsc); + switch (TREE_CODE_CLASS (TREE_CODE (rhsop))) + { + /* RHS that consist of unary operations, + exceptional types, or bare decls/constants, get + handled directly by get_constraint_for. */ + case tcc_reference: + case tcc_declaration: + case tcc_constant: + case tcc_exceptional: + case tcc_expression: + case tcc_unary: + { + unsigned int j; + + get_constraint_for (rhsop, &rhsc); + for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++) + { + struct constraint_expr *c2; + unsigned int k; + + for (k = 0; VEC_iterate (ce_s, rhsc, k, c2); k++) + process_constraint (new_constraint (*c, *c2)); + } + + } + break; + + case tcc_binary: + { + /* For pointer arithmetic of the form + PTR + CST, we can simply use PTR's + constraint because pointer arithmetic is + not allowed to go out of bounds. */ + if (handle_ptr_arith (lhsc, rhsop)) + break; + } + /* FALLTHRU */ + + /* Otherwise, walk each operand. Notice that we + can't use the operand interface because we need + to process expressions other than simple operands + (e.g. INDIRECT_REF, ADDR_EXPR, CALL_EXPR). */ + default: + for (i = 0; i < TREE_CODE_LENGTH (TREE_CODE (rhsop)); i++) + { + tree op = TREE_OPERAND (rhsop, i); + unsigned int j; + + gcc_assert (VEC_length (ce_s, rhsc) == 0); + get_constraint_for (op, &rhsc); + for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++) + { + struct constraint_expr *c2; + while (VEC_length (ce_s, rhsc) > 0) + { + c2 = VEC_last (ce_s, rhsc); + process_constraint (new_constraint (*c, *c2)); + VEC_pop (ce_s, rhsc); + } + } + } + } + } + } + } + + /* After promoting variables and computing aliasing we will + need to re-scan most statements. FIXME: Try to minimize the + number of statements re-scanned. It's not really necessary to + re-scan *all* statements. */ + mark_stmt_modified (origt); + VEC_free (ce_s, heap, rhsc); + VEC_free (ce_s, heap, lhsc); +} + + +/* Find the first varinfo in the same variable as START that overlaps with + OFFSET. + Effectively, walk the chain of fields for the variable START to find the + first field that overlaps with OFFSET. + Return NULL if we can't find one. */ + +static varinfo_t +first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset) +{ + varinfo_t curr = start; + while (curr) + { + /* We may not find a variable in the field list with the actual + offset when when we have glommed a structure to a variable. + In that case, however, offset should still be within the size + of the variable. */ + if (offset >= curr->offset && offset < (curr->offset + curr->size)) + return curr; + curr = curr->next; + } + return NULL; +} + + +/* Insert the varinfo FIELD into the field list for BASE, at the front + of the list. */ + +static void +insert_into_field_list (varinfo_t base, varinfo_t field) +{ + varinfo_t prev = base; + varinfo_t curr = base->next; + + field->next = curr; + prev->next = field; +} + +/* Insert the varinfo FIELD into the field list for BASE, ordered by + offset. */ + +static void +insert_into_field_list_sorted (varinfo_t base, varinfo_t field) +{ + varinfo_t prev = base; + varinfo_t curr = base->next; + + if (curr == NULL) + { + prev->next = field; + field->next = NULL; + } + else + { + while (curr) + { + if (field->offset <= curr->offset) + break; + prev = curr; + curr = curr->next; + } + field->next = prev->next; + prev->next = field; + } +} + +/* qsort comparison function for two fieldoff's PA and PB */ + +static int +fieldoff_compare (const void *pa, const void *pb) +{ + const fieldoff_s *foa = (const fieldoff_s *)pa; + const fieldoff_s *fob = (const fieldoff_s *)pb; + HOST_WIDE_INT foasize, fobsize; + + if (foa->offset != fob->offset) + return foa->offset - fob->offset; + + foasize = TREE_INT_CST_LOW (foa->size); + fobsize = TREE_INT_CST_LOW (fob->size); + return foasize - fobsize; +} + +/* Sort a fieldstack according to the field offset and sizes. */ +void +sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack) +{ + qsort (VEC_address (fieldoff_s, fieldstack), + VEC_length (fieldoff_s, fieldstack), + sizeof (fieldoff_s), + fieldoff_compare); +} + +/* Given a TYPE, and a vector of field offsets FIELDSTACK, push all the fields + of TYPE onto fieldstack, recording their offsets along the way. + OFFSET is used to keep track of the offset in this entire structure, rather + than just the immediately containing structure. Returns the number + of fields pushed. + HAS_UNION is set to true if we find a union type as a field of + TYPE. */ + +int +push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack, + HOST_WIDE_INT offset, bool *has_union) +{ + tree field; + int count = 0; + + if (TREE_CODE (type) == COMPLEX_TYPE) + { + fieldoff_s *real_part, *img_part; + real_part = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL); + real_part->type = TREE_TYPE (type); + real_part->size = TYPE_SIZE (TREE_TYPE (type)); + real_part->offset = offset; + real_part->decl = NULL_TREE; + + img_part = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL); + img_part->type = TREE_TYPE (type); + img_part->size = TYPE_SIZE (TREE_TYPE (type)); + img_part->offset = offset + TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (type))); + img_part->decl = NULL_TREE; + + return 2; + } + + if (TREE_CODE (type) == ARRAY_TYPE) + { + tree sz = TYPE_SIZE (type); + tree elsz = TYPE_SIZE (TREE_TYPE (type)); + HOST_WIDE_INT nr; + int i; + + if (! sz + || ! host_integerp (sz, 1) + || TREE_INT_CST_LOW (sz) == 0 + || ! elsz + || ! host_integerp (elsz, 1) + || TREE_INT_CST_LOW (elsz) == 0) + return 0; + + nr = TREE_INT_CST_LOW (sz) / TREE_INT_CST_LOW (elsz); + if (nr > SALIAS_MAX_ARRAY_ELEMENTS) + return 0; + + for (i = 0; i < nr; ++i) + { + bool push = false; + int pushed = 0; + + if (has_union + && (TREE_CODE (TREE_TYPE (type)) == QUAL_UNION_TYPE + || TREE_CODE (TREE_TYPE (type)) == UNION_TYPE)) + *has_union = true; + + if (!AGGREGATE_TYPE_P (TREE_TYPE (type))) /* var_can_have_subvars */ + push = true; + else if (!(pushed = push_fields_onto_fieldstack + (TREE_TYPE (type), fieldstack, + offset + i * TREE_INT_CST_LOW (elsz), has_union))) + /* Empty structures may have actual size, like in C++. So + see if we didn't push any subfields and the size is + nonzero, push the field onto the stack */ + push = true; + + if (push) + { + fieldoff_s *pair; + + pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL); + pair->type = TREE_TYPE (type); + pair->size = elsz; + pair->decl = NULL_TREE; + pair->offset = offset + i * TREE_INT_CST_LOW (elsz); + count++; + } + else + count += pushed; + } + + return count; + } + + for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field)) + if (TREE_CODE (field) == FIELD_DECL) + { + bool push = false; + int pushed = 0; + + if (has_union + && (TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE + || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)) + *has_union = true; + + if (!var_can_have_subvars (field)) + push = true; + else if (!(pushed = push_fields_onto_fieldstack + (TREE_TYPE (field), fieldstack, + offset + bitpos_of_field (field), has_union)) + && DECL_SIZE (field) + && !integer_zerop (DECL_SIZE (field))) + /* Empty structures may have actual size, like in C++. So + see if we didn't push any subfields and the size is + nonzero, push the field onto the stack */ + push = true; + + if (push) + { + fieldoff_s *pair; + + pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL); + pair->type = TREE_TYPE (field); + pair->size = DECL_SIZE (field); + pair->decl = field; + pair->offset = offset + bitpos_of_field (field); + count++; + } + else + count += pushed; + } + + return count; +} + +/* Create a constraint from ESCAPED_VARS variable to VI. */ +static void +make_constraint_from_escaped (varinfo_t vi) +{ + struct constraint_expr lhs, rhs; + + lhs.var = vi->id; + lhs.offset = 0; + lhs.type = SCALAR; + + rhs.var = escaped_vars_id; + rhs.offset = 0; + rhs.type = SCALAR; + process_constraint (new_constraint (lhs, rhs)); +} + +/* Create a constraint to the ESCAPED_VARS variable from constraint + expression RHS. */ + +static void +make_constraint_to_escaped (struct constraint_expr rhs) +{ + struct constraint_expr lhs; + + lhs.var = escaped_vars_id; + lhs.offset = 0; + lhs.type = SCALAR; + + process_constraint (new_constraint (lhs, rhs)); +} + +/* Count the number of arguments DECL has, and set IS_VARARGS to true + if it is a varargs function. */ + +static unsigned int +count_num_arguments (tree decl, bool *is_varargs) +{ + unsigned int i = 0; + tree t; + + for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); + t; + t = TREE_CHAIN (t)) + { + if (TREE_VALUE (t) == void_type_node) + break; + i++; + } + + if (!t) + *is_varargs = true; + return i; +} + +/* Creation function node for DECL, using NAME, and return the index + of the variable we've created for the function. */ + +static unsigned int +create_function_info_for (tree decl, const char *name) +{ + unsigned int index = VEC_length (varinfo_t, varmap); + varinfo_t vi; + tree arg; + unsigned int i; + bool is_varargs = false; + + /* Create the variable info. */ + + vi = new_var_info (decl, index, name, index); + vi->decl = decl; + vi->offset = 0; + vi->has_union = 0; + vi->size = 1; + vi->fullsize = count_num_arguments (decl, &is_varargs) + 1; + insert_id_for_tree (vi->decl, index); + VEC_safe_push (varinfo_t, heap, varmap, vi); + + stats.total_vars++; + + /* If it's varargs, we don't know how many arguments it has, so we + can't do much. + */ + if (is_varargs) + { + vi->fullsize = ~0; + vi->size = ~0; + vi->is_unknown_size_var = true; + return index; + } + + + arg = DECL_ARGUMENTS (decl); + + /* Set up variables for each argument. */ + for (i = 1; i < vi->fullsize; i++) + { + varinfo_t argvi; + const char *newname; + char *tempname; + unsigned int newindex; + tree argdecl = decl; + + if (arg) + argdecl = arg; + + newindex = VEC_length (varinfo_t, varmap); + asprintf (&tempname, "%s.arg%d", name, i-1); + newname = ggc_strdup (tempname); + free (tempname); + + argvi = new_var_info (argdecl, newindex,newname, newindex); + argvi->decl = argdecl; + VEC_safe_push (varinfo_t, heap, varmap, argvi); + argvi->offset = i; + argvi->size = 1; + argvi->fullsize = vi->fullsize; + argvi->has_union = false; + insert_into_field_list_sorted (vi, argvi); + stats.total_vars ++; + if (arg) + { + insert_id_for_tree (arg, newindex); + arg = TREE_CHAIN (arg); + } + } + + /* Create a variable for the return var. */ + if (DECL_RESULT (decl) != NULL + || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl)))) + { + varinfo_t resultvi; + const char *newname; + char *tempname; + unsigned int newindex; + tree resultdecl = decl; + + vi->fullsize ++; + + if (DECL_RESULT (decl)) + resultdecl = DECL_RESULT (decl); + + newindex = VEC_length (varinfo_t, varmap); + asprintf (&tempname, "%s.result", name); + newname = ggc_strdup (tempname); + free (tempname); + + resultvi = new_var_info (resultdecl, newindex, newname, newindex); + resultvi->decl = resultdecl; + VEC_safe_push (varinfo_t, heap, varmap, resultvi); + resultvi->offset = i; + resultvi->size = 1; + resultvi->fullsize = vi->fullsize; + resultvi->has_union = false; + insert_into_field_list_sorted (vi, resultvi); + stats.total_vars ++; + if (DECL_RESULT (decl)) + insert_id_for_tree (DECL_RESULT (decl), newindex); + } + return index; +} + + +/* Return true if FIELDSTACK contains fields that overlap. + FIELDSTACK is assumed to be sorted by offset. */ + +static bool +check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack) +{ + fieldoff_s *fo = NULL; + unsigned int i; + HOST_WIDE_INT lastoffset = -1; + + for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++) + { + if (fo->offset == lastoffset) + return true; + lastoffset = fo->offset; + } + return false; +} + +/* This function is called through walk_tree to walk global + initializers looking for constraints we need to add to the + constraint list. */ + +static tree +find_global_initializers (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED, + void *viv) +{ + varinfo_t vi = (varinfo_t)viv; + tree t = *tp; + + switch (TREE_CODE (t)) + { + /* Dereferences and addressofs are the only important things + here, and i don't even remember if dereferences are legal + here in initializers. */ + case INDIRECT_REF: + case ADDR_EXPR: + { + struct constraint_expr *c; + size_t i; + + VEC(ce_s, heap) *rhsc = NULL; + get_constraint_for (t, &rhsc); + for (i = 0; VEC_iterate (ce_s, rhsc, i, c); i++) + { + struct constraint_expr lhs; + + lhs.var = vi->id; + lhs.type = SCALAR; + lhs.offset = 0; + process_constraint (new_constraint (lhs, *c)); + } + + VEC_free (ce_s, heap, rhsc); + } + break; + case VAR_DECL: + /* We might not have walked this because we skip + DECL_EXTERNALs during the initial scan. */ + if (referenced_vars) + { + get_var_ann (t); + if (referenced_var_check_and_insert (t)) + mark_sym_for_renaming (t); + } + break; + default: + break; + } + return NULL_TREE; +} + +/* Create a varinfo structure for NAME and DECL, and add it to VARMAP. + This will also create any varinfo structures necessary for fields + of DECL. */ + +static unsigned int +create_variable_info_for (tree decl, const char *name) +{ + unsigned int index = VEC_length (varinfo_t, varmap); + varinfo_t vi; + tree decltype = TREE_TYPE (decl); + tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decltype); + bool notokay = false; + bool hasunion; + bool is_global = DECL_P (decl) ? is_global_var (decl) : false; + VEC (fieldoff_s,heap) *fieldstack = NULL; + + if (TREE_CODE (decl) == FUNCTION_DECL && in_ipa_mode) + return create_function_info_for (decl, name); + + hasunion = TREE_CODE (decltype) == UNION_TYPE + || TREE_CODE (decltype) == QUAL_UNION_TYPE; + if (var_can_have_subvars (decl) && use_field_sensitive && !hasunion) + { + push_fields_onto_fieldstack (decltype, &fieldstack, 0, &hasunion); + if (hasunion) + { + VEC_free (fieldoff_s, heap, fieldstack); + notokay = true; + } + } + + + /* If the variable doesn't have subvars, we may end up needing to + sort the field list and create fake variables for all the + fields. */ + vi = new_var_info (decl, index, name, index); + vi->decl = decl; + vi->offset = 0; + vi->has_union = hasunion; + if (!declsize + || TREE_CODE (declsize) != INTEGER_CST + || TREE_CODE (decltype) == UNION_TYPE + || TREE_CODE (decltype) == QUAL_UNION_TYPE) + { + vi->is_unknown_size_var = true; + vi->fullsize = ~0; + vi->size = ~0; + } + else + { + vi->fullsize = TREE_INT_CST_LOW (declsize); + vi->size = vi->fullsize; + } + + insert_id_for_tree (vi->decl, index); + VEC_safe_push (varinfo_t, heap, varmap, vi); + if (is_global && (!flag_whole_program || !in_ipa_mode)) + { + make_constraint_from_escaped (vi); + + /* If the variable can't be aliased, there is no point in + putting it in the set of nonlocal vars. */ + if (may_be_aliased (vi->decl)) + { + struct constraint_expr rhs; + rhs.var = index; + rhs.type = ADDRESSOF; + rhs.offset = 0; + make_constraint_to_escaped (rhs); + } + + if (TREE_CODE (decl) != FUNCTION_DECL && DECL_INITIAL (decl)) + { + walk_tree_without_duplicates (&DECL_INITIAL (decl), + find_global_initializers, + (void *)vi); + } + } + + stats.total_vars++; + if (use_field_sensitive + && !notokay + && !vi->is_unknown_size_var + && var_can_have_subvars (decl) + && VEC_length (fieldoff_s, fieldstack) <= MAX_FIELDS_FOR_FIELD_SENSITIVE) + { + unsigned int newindex = VEC_length (varinfo_t, varmap); + fieldoff_s *fo = NULL; + unsigned int i; + + for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++) + { + if (! fo->size + || TREE_CODE (fo->size) != INTEGER_CST + || fo->offset < 0) + { + notokay = true; + break; + } + } + + /* We can't sort them if we have a field with a variable sized type, + which will make notokay = true. In that case, we are going to return + without creating varinfos for the fields anyway, so sorting them is a + waste to boot. */ + if (!notokay) + { + sort_fieldstack (fieldstack); + /* Due to some C++ FE issues, like PR 22488, we might end up + what appear to be overlapping fields even though they, + in reality, do not overlap. Until the C++ FE is fixed, + we will simply disable field-sensitivity for these cases. */ + notokay = check_for_overlaps (fieldstack); + } + + + if (VEC_length (fieldoff_s, fieldstack) != 0) + fo = VEC_index (fieldoff_s, fieldstack, 0); + + if (fo == NULL || notokay) + { + vi->is_unknown_size_var = 1; + vi->fullsize = ~0; + vi->size = ~0; + VEC_free (fieldoff_s, heap, fieldstack); + return index; + } + + vi->size = TREE_INT_CST_LOW (fo->size); + vi->offset = fo->offset; + for (i = VEC_length (fieldoff_s, fieldstack) - 1; + i >= 1 && VEC_iterate (fieldoff_s, fieldstack, i, fo); + i--) + { + varinfo_t newvi; + const char *newname = "NULL"; + char *tempname; + + newindex = VEC_length (varinfo_t, varmap); + if (dump_file) + { + if (fo->decl) + asprintf (&tempname, "%s.%s", + vi->name, alias_get_name (fo->decl)); + else + asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC, + vi->name, fo->offset); + newname = ggc_strdup (tempname); + free (tempname); + } + newvi = new_var_info (decl, newindex, newname, newindex); + newvi->offset = fo->offset; + newvi->size = TREE_INT_CST_LOW (fo->size); + newvi->fullsize = vi->fullsize; + insert_into_field_list (vi, newvi); + VEC_safe_push (varinfo_t, heap, varmap, newvi); + if (is_global && (!flag_whole_program || !in_ipa_mode)) + { + /* If the variable can't be aliased, there is no point in + putting it in the set of nonlocal vars. */ + if (may_be_aliased (vi->decl)) + { + struct constraint_expr rhs; + + rhs.var = newindex; + rhs.type = ADDRESSOF; + rhs.offset = 0; + make_constraint_to_escaped (rhs); + } + make_constraint_from_escaped (newvi); + } + + stats.total_vars++; + } + VEC_free (fieldoff_s, heap, fieldstack); + } + return index; +} + +/* Print out the points-to solution for VAR to FILE. */ + +void +dump_solution_for_var (FILE *file, unsigned int var) +{ + varinfo_t vi = get_varinfo (var); + unsigned int i; + bitmap_iterator bi; + + fprintf (file, "%s = { ", vi->name); + EXECUTE_IF_SET_IN_BITMAP (get_varinfo (vi->node)->solution, 0, i, bi) + { + fprintf (file, "%s ", get_varinfo (i)->name); + } + fprintf (file, "}\n"); +} + +/* Print the points-to solution for VAR to stdout. */ + +void +debug_solution_for_var (unsigned int var) +{ + dump_solution_for_var (stdout, var); +} + +/* Create varinfo structures for all of the variables in the + function for intraprocedural mode. */ + +static void +intra_create_variable_infos (void) +{ + tree t; + struct constraint_expr lhs, rhs; + varinfo_t nonlocal_vi; + + /* For each incoming pointer argument arg, ARG = ESCAPED_VARS or a + dummy variable if flag_argument_noalias > 2. */ + for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t)) + { + varinfo_t p; + unsigned int arg_id; + + if (!could_have_pointers (t)) + continue; + + arg_id = get_id_for_tree (t); + + /* With flag_argument_noalias greater than two means that the incoming + argument cannot alias anything except for itself so create a HEAP + variable. */ + if (POINTER_TYPE_P (TREE_TYPE (t)) + && flag_argument_noalias > 2) + { + varinfo_t vi; + tree heapvar = heapvar_lookup (t); + unsigned int id; + + lhs.offset = 0; + lhs.type = SCALAR; + lhs.var = get_id_for_tree (t); + + if (heapvar == NULL_TREE) + { + heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)), + "PARM_NOALIAS"); + DECL_EXTERNAL (heapvar) = 1; + if (referenced_vars) + add_referenced_var (heapvar); + heapvar_insert (t, heapvar); + } + id = get_id_for_tree (heapvar); + vi = get_varinfo (id); + vi->is_artificial_var = 1; + vi->is_heap_var = 1; + rhs.var = id; + rhs.type = ADDRESSOF; + rhs.offset = 0; + for (p = get_varinfo (lhs.var); p; p = p->next) + { + struct constraint_expr temp = lhs; + temp.var = p->id; + process_constraint (new_constraint (temp, rhs)); + } + } + else + { + for (p = get_varinfo (arg_id); p; p = p->next) + make_constraint_from_escaped (p); + } + } + if (!nonlocal_all) + nonlocal_all = create_nonlocal_var (void_type_node); + + /* Create variable info for the nonlocal var if it does not + exist. */ + nonlocal_vars_id = create_variable_info_for (nonlocal_all, + get_name (nonlocal_all)); + nonlocal_vi = get_varinfo (nonlocal_vars_id); + nonlocal_vi->is_artificial_var = 1; + nonlocal_vi->is_heap_var = 1; + nonlocal_vi->is_unknown_size_var = 1; + nonlocal_vi->directly_dereferenced = true; + + rhs.var = nonlocal_vars_id; + rhs.type = ADDRESSOF; + rhs.offset = 0; + + lhs.var = escaped_vars_id; + lhs.type = SCALAR; + lhs.offset = 0; + + process_constraint (new_constraint (lhs, rhs)); +} + +/* Set bits in INTO corresponding to the variable uids in solution set + FROM, which came from variable PTR. + For variables that are actually dereferenced, we also use type + based alias analysis to prune the points-to sets. */ + +static void +set_uids_in_ptset (tree ptr, bitmap into, bitmap from) +{ + unsigned int i; + bitmap_iterator bi; + subvar_t sv; + unsigned HOST_WIDE_INT ptr_alias_set = get_alias_set (TREE_TYPE (ptr)); + + EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi) + { + varinfo_t vi = get_varinfo (i); + unsigned HOST_WIDE_INT var_alias_set; + + /* The only artificial variables that are allowed in a may-alias + set are heap variables. */ + if (vi->is_artificial_var && !vi->is_heap_var) + continue; + + if (vi->has_union && get_subvars_for_var (vi->decl) != NULL) + { + /* Variables containing unions may need to be converted to + their SFT's, because SFT's can have unions and we cannot. */ + for (sv = get_subvars_for_var (vi->decl); sv; sv = sv->next) + bitmap_set_bit (into, DECL_UID (sv->var)); + } + else if (TREE_CODE (vi->decl) == VAR_DECL + || TREE_CODE (vi->decl) == PARM_DECL) + { + if (var_can_have_subvars (vi->decl) + && get_subvars_for_var (vi->decl)) + { + /* If VI->DECL is an aggregate for which we created + SFTs, add the SFT corresponding to VI->OFFSET. */ + tree sft = get_subvar_at (vi->decl, vi->offset); + if (sft) + { + var_alias_set = get_alias_set (sft); + if (!vi->directly_dereferenced + || alias_sets_conflict_p (ptr_alias_set, var_alias_set)) + bitmap_set_bit (into, DECL_UID (sft)); + } + } + else + { + /* Otherwise, just add VI->DECL to the alias set. + Don't type prune artificial vars. */ + if (vi->is_artificial_var) + bitmap_set_bit (into, DECL_UID (vi->decl)); + else + { + var_alias_set = get_alias_set (vi->decl); + if (!vi->directly_dereferenced + || alias_sets_conflict_p (ptr_alias_set, var_alias_set)) + bitmap_set_bit (into, DECL_UID (vi->decl)); + } + } + } + } +} + + +static bool have_alias_info = false; + +/* Given a pointer variable P, fill in its points-to set, or return + false if we can't. */ + +bool +find_what_p_points_to (tree p) +{ + unsigned int id = 0; + tree lookup_p = p; + + if (!have_alias_info) + return false; + + /* For parameters, get at the points-to set for the actual parm + decl. */ + if (TREE_CODE (p) == SSA_NAME + && TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL + && default_def (SSA_NAME_VAR (p)) == p) + lookup_p = SSA_NAME_VAR (p); + + if (lookup_id_for_tree (lookup_p, &id)) + { + varinfo_t vi = get_varinfo (id); + + if (vi->is_artificial_var) + return false; + + /* See if this is a field or a structure. */ + if (vi->size != vi->fullsize) + { + /* Nothing currently asks about structure fields directly, + but when they do, we need code here to hand back the + points-to set. */ + if (!var_can_have_subvars (vi->decl) + || get_subvars_for_var (vi->decl) == NULL) + return false; + } + else + { + struct ptr_info_def *pi = get_ptr_info (p); + unsigned int i; + bitmap_iterator bi; + + /* This variable may have been collapsed, let's get the real + variable. */ + vi = get_varinfo (vi->node); + + /* Translate artificial variables into SSA_NAME_PTR_INFO + attributes. */ + EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi) + { + varinfo_t vi = get_varinfo (i); + + if (vi->is_artificial_var) + { + /* FIXME. READONLY should be handled better so that + flow insensitive aliasing can disregard writable + aliases. */ + if (vi->id == nothing_id) + pi->pt_null = 1; + else if (vi->id == anything_id) + pi->pt_anything = 1; + else if (vi->id == readonly_id) + pi->pt_anything = 1; + else if (vi->id == integer_id) + pi->pt_anything = 1; + else if (vi->is_heap_var) + pi->pt_global_mem = 1; + } + } + + if (pi->pt_anything) + return false; + + if (!pi->pt_vars) + pi->pt_vars = BITMAP_GGC_ALLOC (); + + set_uids_in_ptset (vi->decl, pi->pt_vars, vi->solution); + + if (bitmap_empty_p (pi->pt_vars)) + pi->pt_vars = NULL; + + return true; + } + } + + return false; +} + + + +/* Dump points-to information to OUTFILE. */ + +void +dump_sa_points_to_info (FILE *outfile) +{ + unsigned int i; + + fprintf (outfile, "\nPoints-to sets\n\n"); + + if (dump_flags & TDF_STATS) + { + fprintf (outfile, "Stats:\n"); + fprintf (outfile, "Total vars: %d\n", stats.total_vars); + fprintf (outfile, "Statically unified vars: %d\n", + stats.unified_vars_static); + fprintf (outfile, "Collapsed vars: %d\n", stats.collapsed_vars); + fprintf (outfile, "Dynamically unified vars: %d\n", + stats.unified_vars_dynamic); + fprintf (outfile, "Iterations: %d\n", stats.iterations); + fprintf (outfile, "Number of edges: %d\n", stats.num_edges); + } + + for (i = 0; i < VEC_length (varinfo_t, varmap); i++) + dump_solution_for_var (outfile, i); +} + + +/* Debug points-to information to stderr. */ + +void +debug_sa_points_to_info (void) +{ + dump_sa_points_to_info (stderr); +} + + +/* Initialize the always-existing constraint variables for NULL + ANYTHING, READONLY, and INTEGER */ + +static void +init_base_vars (void) +{ + struct constraint_expr lhs, rhs; + + /* Create the NULL variable, used to represent that a variable points + to NULL. */ + nothing_tree = create_tmp_var_raw (void_type_node, "NULL"); + var_nothing = new_var_info (nothing_tree, 0, "NULL", 0); + insert_id_for_tree (nothing_tree, 0); + var_nothing->is_artificial_var = 1; + var_nothing->offset = 0; + var_nothing->size = ~0; + var_nothing->fullsize = ~0; + var_nothing->is_special_var = 1; + nothing_id = 0; + VEC_safe_push (varinfo_t, heap, varmap, var_nothing); + + /* Create the ANYTHING variable, used to represent that a variable + points to some unknown piece of memory. */ + anything_tree = create_tmp_var_raw (void_type_node, "ANYTHING"); + var_anything = new_var_info (anything_tree, 1, "ANYTHING", 1); + insert_id_for_tree (anything_tree, 1); + var_anything->is_artificial_var = 1; + var_anything->size = ~0; + var_anything->offset = 0; + var_anything->next = NULL; + var_anything->fullsize = ~0; + var_anything->is_special_var = 1; + anything_id = 1; + + /* Anything points to anything. This makes deref constraints just + work in the presence of linked list and other p = *p type loops, + by saying that *ANYTHING = ANYTHING. */ + VEC_safe_push (varinfo_t, heap, varmap, var_anything); + lhs.type = SCALAR; + lhs.var = anything_id; + lhs.offset = 0; + rhs.type = ADDRESSOF; + rhs.var = anything_id; + rhs.offset = 0; + var_anything->address_taken = true; + + /* This specifically does not use process_constraint because + process_constraint ignores all anything = anything constraints, since all + but this one are redundant. */ + VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs)); + + /* Create the READONLY variable, used to represent that a variable + points to readonly memory. */ + readonly_tree = create_tmp_var_raw (void_type_node, "READONLY"); + var_readonly = new_var_info (readonly_tree, 2, "READONLY", 2); + var_readonly->is_artificial_var = 1; + var_readonly->offset = 0; + var_readonly->size = ~0; + var_readonly->fullsize = ~0; + var_readonly->next = NULL; + var_readonly->is_special_var = 1; + insert_id_for_tree (readonly_tree, 2); + readonly_id = 2; + VEC_safe_push (varinfo_t, heap, varmap, var_readonly); + + /* readonly memory points to anything, in order to make deref + easier. In reality, it points to anything the particular + readonly variable can point to, but we don't track this + separately. */ + lhs.type = SCALAR; + lhs.var = readonly_id; + lhs.offset = 0; + rhs.type = ADDRESSOF; + rhs.var = anything_id; + rhs.offset = 0; + + process_constraint (new_constraint (lhs, rhs)); + + /* Create the INTEGER variable, used to represent that a variable points + to an INTEGER. */ + integer_tree = create_tmp_var_raw (void_type_node, "INTEGER"); + var_integer = new_var_info (integer_tree, 3, "INTEGER", 3); + insert_id_for_tree (integer_tree, 3); + var_integer->is_artificial_var = 1; + var_integer->size = ~0; + var_integer->fullsize = ~0; + var_integer->offset = 0; + var_integer->next = NULL; + var_integer->is_special_var = 1; + integer_id = 3; + VEC_safe_push (varinfo_t, heap, varmap, var_integer); + + /* INTEGER = ANYTHING, because we don't know where a dereference of + a random integer will point to. */ + lhs.type = SCALAR; + lhs.var = integer_id; + lhs.offset = 0; + rhs.type = ADDRESSOF; + rhs.var = anything_id; + rhs.offset = 0; + process_constraint (new_constraint (lhs, rhs)); + + /* Create the ESCAPED_VARS variable used to represent variables that + escape this function. */ + escaped_vars_tree = create_tmp_var_raw (void_type_node, "ESCAPED_VARS"); + var_escaped_vars = new_var_info (escaped_vars_tree, 4, "ESCAPED_VARS", 4); + insert_id_for_tree (escaped_vars_tree, 4); + var_escaped_vars->is_artificial_var = 1; + var_escaped_vars->size = ~0; + var_escaped_vars->fullsize = ~0; + var_escaped_vars->offset = 0; + var_escaped_vars->next = NULL; + escaped_vars_id = 4; + VEC_safe_push (varinfo_t, heap, varmap, var_escaped_vars); + + /* ESCAPED_VARS = *ESCAPED_VARS */ + lhs.type = SCALAR; + lhs.var = escaped_vars_id; + lhs.offset = 0; + rhs.type = DEREF; + rhs.var = escaped_vars_id; + rhs.offset = 0; + process_constraint (new_constraint (lhs, rhs)); + +} + +/* Initialize things necessary to perform PTA */ + +static void +init_alias_vars (void) +{ + bitmap_obstack_initialize (&ptabitmap_obstack); + bitmap_obstack_initialize (&predbitmap_obstack); + + constraint_pool = create_alloc_pool ("Constraint pool", + sizeof (struct constraint), 30); + variable_info_pool = create_alloc_pool ("Variable info pool", + sizeof (struct variable_info), 30); + constraint_edge_pool = create_alloc_pool ("Constraint edges", + sizeof (struct constraint_edge), 30); + + constraints = VEC_alloc (constraint_t, heap, 8); + varmap = VEC_alloc (varinfo_t, heap, 8); + id_for_tree = htab_create (10, tree_id_hash, tree_id_eq, free); + memset (&stats, 0, sizeof (stats)); + + init_base_vars (); +} + +/* Given a statement STMT, generate necessary constraints to + escaped_vars for the escaping variables. */ + +static void +find_escape_constraints (tree stmt) +{ + enum escape_type stmt_escape_type = is_escape_site (stmt); + tree rhs; + VEC(ce_s, heap) *rhsc = NULL; + struct constraint_expr *c; + size_t i; + + if (stmt_escape_type == NO_ESCAPE) + return; + + if (TREE_CODE (stmt) == RETURN_EXPR) + { + /* Returns are either bare, with an embedded MODIFY_EXPR, or + just a plain old expression. */ + if (!TREE_OPERAND (stmt, 0)) + return; + if (TREE_CODE (TREE_OPERAND (stmt, 0)) == MODIFY_EXPR) + rhs = TREE_OPERAND (TREE_OPERAND (stmt, 0), 1); + else + rhs = TREE_OPERAND (stmt, 0); + + get_constraint_for (rhs, &rhsc); + for (i = 0; VEC_iterate (ce_s, rhsc, i, c); i++) + make_constraint_to_escaped (*c); + VEC_free (ce_s, heap, rhsc); + return; + } + else if (TREE_CODE (stmt) == ASM_EXPR) + { + /* Whatever the inputs of the ASM are, escape. */ + tree arg; + + for (arg = ASM_INPUTS (stmt); arg; arg = TREE_CHAIN (arg)) + { + rhsc = NULL; + get_constraint_for (TREE_VALUE (arg), &rhsc); + for (i = 0; VEC_iterate (ce_s, rhsc, i, c); i++) + make_constraint_to_escaped (*c); + VEC_free (ce_s, heap, rhsc); + } + return; + } + else if (TREE_CODE (stmt) == CALL_EXPR + || (TREE_CODE (stmt) == MODIFY_EXPR + && TREE_CODE (TREE_OPERAND (stmt, 1)) == CALL_EXPR)) + { + /* Calls cause all of the arguments passed in to escape. */ + tree arg; + + if (TREE_CODE (stmt) == MODIFY_EXPR) + stmt = TREE_OPERAND (stmt, 1); + for (arg = TREE_OPERAND (stmt, 1); arg; arg = TREE_CHAIN (arg)) + { + if (POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (arg)))) + { + rhsc = NULL; + get_constraint_for (TREE_VALUE (arg), &rhsc); + for (i = 0; VEC_iterate (ce_s, rhsc, i, c); i++) + make_constraint_to_escaped (*c); + VEC_free (ce_s, heap, rhsc); + } + } + return; + } + else + { + gcc_assert (TREE_CODE (stmt) == MODIFY_EXPR); + } + + gcc_assert (stmt_escape_type == ESCAPE_BAD_CAST + || stmt_escape_type == ESCAPE_STORED_IN_GLOBAL + || stmt_escape_type == ESCAPE_UNKNOWN); + rhs = TREE_OPERAND (stmt, 1); + + /* Look through casts for the real escaping variable. + Constants don't really escape, so ignore them. + Otherwise, whatever escapes must be on our RHS. */ + if (TREE_CODE (rhs) == NOP_EXPR + || TREE_CODE (rhs) == CONVERT_EXPR + || TREE_CODE (rhs) == NON_LVALUE_EXPR) + { + get_constraint_for (TREE_OPERAND (rhs, 0), &rhsc); + } + else if (CONSTANT_CLASS_P (rhs)) + return; + else + { + get_constraint_for (rhs, &rhsc); + } + for (i = 0; VEC_iterate (ce_s, rhsc, i, c); i++) + make_constraint_to_escaped (*c); + VEC_free (ce_s, heap, rhsc); +} + +/* Create points-to sets for the current function. See the comments + at the start of the file for an algorithmic overview. */ + +void +compute_points_to_sets (struct alias_info *ai) +{ + basic_block bb; + + timevar_push (TV_TREE_PTA); + + init_alias_vars (); + + intra_create_variable_infos (); + + /* Now walk all statements and derive aliases. */ + FOR_EACH_BB (bb) + { + block_stmt_iterator bsi; + tree phi; + + for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi)) + { + if (is_gimple_reg (PHI_RESULT (phi))) + { + find_func_aliases (phi); + /* Update various related attributes like escaped + addresses, pointer dereferences for loads and stores. + This is used when creating name tags and alias + sets. */ + update_alias_info (phi, ai); + } + } + + for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) + { + tree stmt = bsi_stmt (bsi); + + find_func_aliases (stmt); + find_escape_constraints (stmt); + /* Update various related attributes like escaped + addresses, pointer dereferences for loads and stores. + This is used when creating name tags and alias + sets. */ + update_alias_info (stmt, ai); + } + } + + build_constraint_graph (); + + if (dump_file) + { + fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n"); + dump_constraints (dump_file); + } + + if (dump_file) + fprintf (dump_file, + "\nCollapsing static cycles and doing variable " + "substitution:\n"); + + find_and_collapse_graph_cycles (graph, false); + perform_var_substitution (graph); + + if (dump_file) + fprintf (dump_file, "\nSolving graph:\n"); + + solve_graph (graph); + + if (dump_file) + dump_sa_points_to_info (dump_file); + + have_alias_info = true; + + timevar_pop (TV_TREE_PTA); +} + + +/* Delete created points-to sets. */ + +void +delete_points_to_sets (void) +{ + varinfo_t v; + int i; + + htab_delete (id_for_tree); + bitmap_obstack_release (&ptabitmap_obstack); + bitmap_obstack_release (&predbitmap_obstack); + VEC_free (constraint_t, heap, constraints); + + for (i = 0; VEC_iterate (varinfo_t, varmap, i, v); i++) + { + /* Nonlocal vars may add more varinfos. */ + if (i >= graph_size) + break; + + VEC_free (constraint_edge_t, heap, graph->succs[i]); + VEC_free (constraint_edge_t, heap, graph->preds[i]); + VEC_free (constraint_t, heap, v->complex); + } + free (graph->zero_weight_preds); + free (graph->zero_weight_succs); + free (graph->succs); + free (graph->preds); + free (graph); + + VEC_free (varinfo_t, heap, varmap); + free_alloc_pool (variable_info_pool); + free_alloc_pool (constraint_pool); + free_alloc_pool (constraint_edge_pool); + + have_alias_info = false; +} + +/* Return true if we should execute IPA PTA. */ +static bool +gate_ipa_pta (void) +{ + return (flag_unit_at_a_time != 0 + && flag_ipa_pta + /* Don't bother doing anything if the program has errors. */ + && !(errorcount || sorrycount)); +} + +/* Execute the driver for IPA PTA. */ +static unsigned int +ipa_pta_execute (void) +{ + struct cgraph_node *node; + in_ipa_mode = 1; + init_alias_heapvars (); + init_alias_vars (); + + for (node = cgraph_nodes; node; node = node->next) + { + if (!node->analyzed || cgraph_is_master_clone (node)) + { + unsigned int varid; + + varid = create_function_info_for (node->decl, + cgraph_node_name (node)); + if (node->local.externally_visible) + { + varinfo_t fi = get_varinfo (varid); + for (; fi; fi = fi->next) + make_constraint_from_escaped (fi); + } + } + } + for (node = cgraph_nodes; node; node = node->next) + { + if (node->analyzed && cgraph_is_master_clone (node)) + { + struct function *cfun = DECL_STRUCT_FUNCTION (node->decl); + basic_block bb; + tree old_func_decl = current_function_decl; + if (dump_file) + fprintf (dump_file, + "Generating constraints for %s\n", + cgraph_node_name (node)); + push_cfun (cfun); + current_function_decl = node->decl; + + FOR_EACH_BB_FN (bb, cfun) + { + block_stmt_iterator bsi; + tree phi; + + for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi)) + { + if (is_gimple_reg (PHI_RESULT (phi))) + { + find_func_aliases (phi); + } + } + + for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) + { + tree stmt = bsi_stmt (bsi); + find_func_aliases (stmt); + } + } + current_function_decl = old_func_decl; + pop_cfun (); + } + else + { + /* Make point to anything. */ + } + } + + build_constraint_graph (); + + if (dump_file) + { + fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n"); + dump_constraints (dump_file); + } + + if (dump_file) + fprintf (dump_file, + "\nCollapsing static cycles and doing variable " + "substitution:\n"); + + find_and_collapse_graph_cycles (graph, false); + perform_var_substitution (graph); + + if (dump_file) + fprintf (dump_file, "\nSolving graph:\n"); + + solve_graph (graph); + + if (dump_file) + dump_sa_points_to_info (dump_file); + in_ipa_mode = 0; + delete_alias_heapvars (); + delete_points_to_sets (); + return 0; +} + +struct tree_opt_pass pass_ipa_pta = +{ + "pta", /* name */ + gate_ipa_pta, /* gate */ + ipa_pta_execute, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + TV_IPA_PTA, /* tv_id */ + 0, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + 0, /* todo_flags_finish */ + 0 /* letter */ +}; + +/* Initialize the heapvar for statement mapping. */ +void +init_alias_heapvars (void) +{ + heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, tree_map_eq, + NULL); + nonlocal_all = NULL_TREE; +} + +void +delete_alias_heapvars (void) +{ + nonlocal_all = NULL_TREE; + htab_delete (heapvar_for_stmt); +} + + +#include "gt-tree-ssa-structalias.h" |
