/* Tree based points-to analysis
- Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+ Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
Contributed by Daniel Berlin <dberlin@dberlin.org>
This file is part of GCC.
#include "tree-ssa-structalias.h"
#include "cgraph.h"
#include "alias.h"
+#include "pointer-set.h"
/* The idea behind this analyzer is to generate set constraints from the
program, then solve the resulting constraints in order to generate the
http://citeseer.ist.psu.edu/heintze01ultrafast.html
There are three types of real constraint expressions, DEREF,
- ADDRESSOF, and SCALAR. There is one type of fake constraint
- expression, called INCLUDES. Each constraint expression consists
+ 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.
ADDRESSOF is a constraint expression used to represent &x, whether
it appears on the LHS or the RHS of a statement.
- INCLUDES is a constraint expression type used to represent just a
- setting of a bit in the points-to set without having the address
- taken. It exists mainly for abstraction sake, and is used for
- initializing fake variables like the ESCAPED_VARS set.
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.
static bool use_field_sensitive = true;
static int in_ipa_mode = 0;
+
+/* Used for predecessor bitmaps. */
static bitmap_obstack predbitmap_obstack;
-static bitmap_obstack ptabitmap_obstack;
+
+/* Used for points-to sets. */
+static bitmap_obstack pta_obstack;
+
+/* Used for oldsolution members of variables. */
+static bitmap_obstack oldpta_obstack;
+
+/* Used for per-solver-iteration bitmaps. */
static bitmap_obstack iteration_obstack;
static unsigned int create_variable_info_for (tree, const char *);
-static void build_constraint_graph (void);
+typedef struct constraint_graph *constraint_graph_t;
+static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
DEF_VEC_P(constraint_t);
DEF_VEC_ALLOC_P(constraint_t,heap);
static struct constraint_stats
{
unsigned int total_vars;
- unsigned int collapsed_vars;
+ unsigned int nonpointer_vars;
unsigned int unified_vars_static;
unsigned int unified_vars_dynamic;
unsigned int iterations;
unsigned int num_edges;
+ unsigned int num_implicit_edges;
+ unsigned int points_to_sets_created;
} stats;
struct variable_info
/* 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. */
+ so we can prune their points to listed. */
unsigned int directly_dereferenced:1;
/* True if this is a variable created by the constraint analysis, such as
/* True if this is a heap variable. */
unsigned int is_heap_var:1;
+ /* True if we may not use TBAA to prune references to this
+ variable. This is used for C++ placement new. */
+ unsigned int no_tbaa_pruning : 1;
+
/* Points-to set for this variable. */
bitmap solution;
- /* Finished points-to set for this variable (IE what is returned
- from find_what_p_points_to. */
- bitmap finished_solution;
+ /* Old points-to set for this variable. */
+ bitmap oldsolution;
/* 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. */
+ /* Variable id this was collapsed to due to type unsafety. This
+ should be unused completely after build_succ_graph, or something
+ is broken. */
struct variable_info *collapsed_to;
};
typedef struct variable_info *varinfo_t;
DEF_VEC_ALLOC_P(varinfo_t, heap);
-/* Table of variable info structures for constraint variables. Indexed directly
- by variable info id. */
+/* 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 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);
+ varinfo_t v = VEC_index (varinfo_t, varmap, n);
if (v->collapsed_to)
return v->collapsed_to;
heapvar_lookup (tree from)
{
struct tree_map *h, in;
- in.from = from;
+ in.base.from = from;
- h = htab_find_with_hash (heapvar_for_stmt, &in, htab_hash_pointer (from));
+ h = (struct tree_map *) htab_find_with_hash (heapvar_for_stmt, &in,
+ htab_hash_pointer (from));
if (h)
return h->to;
return NULL_TREE;
struct tree_map *h;
void **loc;
- h = ggc_alloc (sizeof (struct tree_map));
+ h = GGC_NEW (struct tree_map);
h->hash = htab_hash_pointer (from);
- h->from = from;
+ h->base.from = from;
h->to = to;
loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->hash, INSERT);
*(struct tree_map **) loc = h;
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)
+new_var_info (tree t, unsigned int id, const char *name)
{
- varinfo_t ret = pool_alloc (variable_info_pool);
+ varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
+ tree var;
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->finished_solution = NULL;
- ret->complex = NULL;
+ var = t;
+ if (TREE_CODE (var) == SSA_NAME)
+ var = SSA_NAME_VAR (var);
+ ret->no_tbaa_pruning = (DECL_P (var)
+ && POINTER_TYPE_P (TREE_TYPE (var))
+ && DECL_NO_TBAA_P (var));
+ ret->solution = BITMAP_ALLOC (&pta_obstack);
+ ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
ret->next = NULL;
ret->collapsed_to = NULL;
return ret;
}
-typedef enum {SCALAR, DEREF, ADDRESSOF, INCLUDES} constraint_expr_type;
+typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
/* An expression that appears in a constraint. */
static alloc_pool constraint_pool;
+DEF_VEC_I(int);
+DEF_VEC_ALLOC_I(int, heap);
+
/* The constraint graph is represented as an array of bitmaps
containing successor nodes. */
struct constraint_graph
{
+ /* Size of this graph, which may be different than the number of
+ nodes in the variable map. */
+ unsigned int size;
+
+ /* Explicit successors of each node. */
bitmap *succs;
+
+ /* Implicit predecessors of each node (Used for variable
+ substitution). */
+ bitmap *implicit_preds;
+
+ /* Explicit predecessors of each node (Used for variable substitution). */
bitmap *preds;
-};
-typedef struct constraint_graph *constraint_graph_t;
+ /* Indirect cycle representatives, or -1 if the node has no indirect
+ cycles. */
+ int *indirect_cycles;
+
+ /* Representative node for a node. rep[a] == a unless the node has
+ been unified. */
+ unsigned int *rep;
+
+ /* Equivalence class representative for a node. This is used for
+ variable substitution. */
+ int *eq_rep;
+
+ /* Label for each node, used during variable substitution. */
+ unsigned int *label;
+
+ /* Bitmap of nodes where the bit is set if the node is a direct
+ node. Used for variable substitution. */
+ sbitmap direct_nodes;
+
+ /* Vector of complex constraints for each graph node. Complex
+ constraints are those involving dereferences or offsets that are
+ not 0. */
+ VEC(constraint_t,heap) **complex;
+};
static constraint_graph_t graph;
+/* During variable substitution and the offline version of indirect
+ cycle finding, we create nodes to represent dereferences and
+ address taken constraints. These represent where these start and
+ end. */
+#define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
+#define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
+#define FIRST_ADDR_NODE (LAST_REF_NODE + 1)
+
+/* Return the representative node for NODE, if NODE has been unioned
+ with another NODE.
+ This function performs path compression along the way to finding
+ the representative. */
+
+static unsigned int
+find (unsigned int node)
+{
+ gcc_assert (node < graph->size);
+ if (graph->rep[node] != node)
+ return graph->rep[node] = find (graph->rep[node]);
+ return node;
+}
+
+/* Union the TO and FROM nodes to the TO nodes.
+ Note that at some point in the future, we may want to do
+ union-by-rank, in which case we are going to have to return the
+ node we unified to. */
+
+static bool
+unite (unsigned int to, unsigned int from)
+{
+ gcc_assert (to < graph->size && from < graph->size);
+ if (to != from && graph->rep[from] != to)
+ {
+ graph->rep[from] = to;
+ return true;
+ }
+ return false;
+}
+
/* 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);
+ constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
ret->lhs = lhs;
ret->rhs = rhs;
return ret;
fprintf (file, "&");
else if (c->rhs.type == DEREF)
fprintf (file, "*");
- else if (c->rhs.type == INCLUDES)
- 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);
- if (c->rhs.type == INCLUDES)
- fprintf (file, "}");
fprintf (file, "\n");
}
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--;
+ sbitmap changed_nodes = all zeroes;
+ changed_count = 0;
+ For each node that is not already collapsed:
+ changed_count++;
+ set bit in changed nodes
while (changed_count > 0)
{
}
}
-/* Insert constraint C into the list of complex constraints for VAR. */
+/* Insert constraint C into the list of complex constraints for graph
+ node VAR. */
static void
-insert_into_complex (unsigned int var, constraint_t c)
+insert_into_complex (constraint_graph_t graph,
+ unsigned int var, constraint_t c)
{
- varinfo_t vi = get_varinfo (var);
- unsigned int place = VEC_lower_bound (constraint_t, vi->complex, c,
+ VEC (constraint_t, heap) *complex = graph->complex[var];
+ unsigned int place = VEC_lower_bound (constraint_t, complex, c,
constraint_less);
- VEC_safe_insert (constraint_t, heap, vi->complex, place, c);
+
+ /* Only insert constraints that do not already exist. */
+ if (place >= VEC_length (constraint_t, complex)
+ || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
+ VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
}
all associated info from SRC to TO. */
static void
-condense_varmap_nodes (unsigned int to, unsigned int src)
+merge_node_constraints (constraint_graph_t graph, unsigned int to,
+ unsigned int from)
{
- 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);
+ gcc_assert (find (from) == to);
/* Move all complex constraints from src node into to node */
- for (i = 0; VEC_iterate (constraint_t, srcvi->complex, i, c); i++)
+ for (i = 0; VEC_iterate (constraint_t, graph->complex[from], i, c); i++)
{
/* In complex constraints for node src, we may have either
- a = *src, and *src = a. */
+ a = *src, and *src = a, or an offseted constraint which are
+ always added to the rhs node's constraints. */
if (c->rhs.type == DEREF)
c->rhs.var = to;
- else
+ else if (c->lhs.type == DEREF)
c->lhs.var = to;
+ else
+ c->rhs.var = to;
}
- constraint_set_union (&tovi->complex, &srcvi->complex);
- VEC_free (constraint_t, heap, srcvi->complex);
- srcvi->complex = NULL;
+ constraint_set_union (&graph->complex[to], &graph->complex[from]);
+ VEC_free (constraint_t, heap, graph->complex[from]);
+ graph->complex[from] = NULL;
}
static void
clear_edges_for_node (constraint_graph_t graph, unsigned int node)
{
- bitmap_iterator bi;
- unsigned int j;
-
- /* Walk the successors, erase the associated preds. */
-
- EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[node], 0, j, bi)
- if (j != node)
- bitmap_clear_bit (graph->preds[j], node);
-
-
- /* Walk the preds, erase the associated succs. */
-
- EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[node], 0, j, bi)
- if (j != node)
- bitmap_clear_bit (graph->succs[j], node);
-
-
- if (graph->preds[node])
- {
- BITMAP_FREE (graph->preds[node]);
- graph->preds[node] = NULL;
- }
-
if (graph->succs[node])
- {
- BITMAP_FREE (graph->succs[node]);
- graph->succs[node] = NULL;
- }
+ BITMAP_FREE (graph->succs[node]);
}
-static bool edge_added = false;
-
/* Merge GRAPH nodes FROM and TO into node TO. */
static void
merge_graph_nodes (constraint_graph_t graph, unsigned int to,
unsigned int from)
{
- unsigned int j;
- bitmap_iterator bi;
-
- /* Merge all the predecessor edges. */
- if (graph->preds[from])
+ if (graph->indirect_cycles[from] != -1)
{
- if (!graph->preds[to])
- graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
-
- EXECUTE_IF_SET_IN_BITMAP (graph->preds[from], 0, j, bi)
+ /* If we have indirect cycles with the from node, and we have
+ none on the to node, the to node has indirect cycles from the
+ from node now that they are unified.
+ If indirect cycles exist on both, unify the nodes that they
+ are in a cycle with, since we know they are in a cycle with
+ each other. */
+ if (graph->indirect_cycles[to] == -1)
{
- if (j != to)
- {
- bitmap_clear_bit (graph->succs[j], from);
- bitmap_set_bit (graph->succs[j], to);
- }
+ graph->indirect_cycles[to] = graph->indirect_cycles[from];
+ }
+ else
+ {
+ unsigned int tonode = find (graph->indirect_cycles[to]);
+ unsigned int fromnode = find (graph->indirect_cycles[from]);
+
+ if (unite (tonode, fromnode))
+ unify_nodes (graph, tonode, fromnode, true);
}
- bitmap_ior_into (graph->preds[to],
- graph->preds[from]);
}
/* Merge all the successor edges. */
if (graph->succs[from])
{
if (!graph->succs[to])
- graph->succs[to] = BITMAP_ALLOC (&ptabitmap_obstack);
- EXECUTE_IF_SET_IN_BITMAP (graph->succs[from], 0, j, bi)
- {
- bitmap_clear_bit (graph->preds[j], from);
- bitmap_set_bit (graph->preds[j], to);
- }
+ graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
bitmap_ior_into (graph->succs[to],
graph->succs[from]);
}
clear_edges_for_node (graph, from);
}
-/* Add a graph edge to GRAPH, going from TO to FROM if
+
+/* Add an indirect graph edge to GRAPH, going from TO to FROM if
+ it doesn't exist in the graph already. */
+
+static void
+add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
+ unsigned int from)
+{
+ if (to == from)
+ return;
+
+ if (!graph->implicit_preds[to])
+ graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
+
+ if (!bitmap_bit_p (graph->implicit_preds[to], from))
+ {
+ stats.num_implicit_edges++;
+ bitmap_set_bit (graph->implicit_preds[to], from);
+ }
+}
+
+/* Add a predecessor graph edge to GRAPH, going from TO to FROM if
+ it doesn't exist in the graph already.
+ Return false if the edge already existed, true otherwise. */
+
+static void
+add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
+ unsigned int from)
+{
+ if (!graph->preds[to])
+ graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
+ if (!bitmap_bit_p (graph->preds[to], from))
+ bitmap_set_bit (graph->preds[to], from);
+}
+
+/* Add a graph edge to GRAPH, going from FROM to TO if
it doesn't exist in the graph already.
Return false if the edge already existed, true otherwise. */
{
bool r = false;
- if (!graph->preds[to])
- graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
if (!graph->succs[from])
- graph->succs[from] = BITMAP_ALLOC (&ptabitmap_obstack);
+ graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
if (!bitmap_bit_p (graph->succs[from], to))
{
- edge_added = true;
r = true;
- stats.num_edges++;
- bitmap_set_bit (graph->preds[to], from);
+ if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
+ stats.num_edges++;
bitmap_set_bit (graph->succs[from], to);
}
return r;
&& bitmap_bit_p (graph->succs[dest], src));
}
-/* Build the constraint graph. */
+/* Build the constraint graph, adding only predecessor edges right now. */
static void
-build_constraint_graph (void)
+build_pred_graph (void)
{
- int i = 0;
+ int i;
constraint_t c;
- int graph_size;
+ unsigned int j;
graph = XNEW (struct constraint_graph);
- graph_size = VEC_length (varinfo_t, varmap) + 1;
- graph->succs = XCNEWVEC (bitmap, graph_size);
- graph->preds = XCNEWVEC (bitmap, graph_size);
+ graph->size = (VEC_length (varinfo_t, varmap)) * 3;
+ graph->succs = XCNEWVEC (bitmap, graph->size);
+ graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
+ graph->preds = XCNEWVEC (bitmap, graph->size);
+ graph->indirect_cycles = XNEWVEC (int, VEC_length (varinfo_t, varmap));
+ graph->label = XCNEWVEC (unsigned int, graph->size);
+ graph->rep = XNEWVEC (unsigned int, graph->size);
+ graph->eq_rep = XNEWVEC (int, graph->size);
+ graph->complex = XCNEWVEC (VEC(constraint_t, heap) *,
+ VEC_length (varinfo_t, varmap));
+ graph->direct_nodes = sbitmap_alloc (graph->size);
+ sbitmap_zero (graph->direct_nodes);
+
+ for (j = 0; j < FIRST_REF_NODE; j++)
+ {
+ if (!get_varinfo (j)->is_special_var)
+ SET_BIT (graph->direct_nodes, j);
+ }
+
+ for (j = 0; j < graph->size; j++)
+ {
+ graph->rep[j] = j;
+ graph->eq_rep[j] = -1;
+ }
+
+ for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
+ graph->indirect_cycles[j] = -1;
for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
{
if (lhs.type == DEREF)
{
- /* *x = y or *x = &y (complex) */
- if (rhs.type == ADDRESSOF || rhsvar > anything_id)
- insert_into_complex (lhsvar, c);
+ /* *x = y. */
+ if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
+ add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
+ if (rhs.type == ADDRESSOF)
+ RESET_BIT (graph->direct_nodes, rhsvar);
}
else if (rhs.type == DEREF)
{
- /* !special var= *y */
- if (!(get_varinfo (lhsvar)->is_special_var))
- insert_into_complex (rhsvar, c);
+ /* x = *y */
+ if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
+ add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
+ else
+ RESET_BIT (graph->direct_nodes, lhsvar);
}
- else if (rhs.type == ADDRESSOF || rhs.type == INCLUDES)
+ else if (rhs.type == ADDRESSOF)
{
/* x = &y */
- bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
+ add_pred_graph_edge (graph, lhsvar, FIRST_ADDR_NODE + rhsvar);
+ /* Implicitly, *x = y */
+ add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
+
+ RESET_BIT (graph->direct_nodes, rhsvar);
}
- else if (lhsvar > anything_id)
+ else if (lhsvar > anything_id
+ && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
{
- /* Ignore self edges, as they can't possibly contribute
- anything */
- if (lhsvar != rhsvar || rhs.offset != 0 || lhs.offset != 0)
- {
- if (rhs.offset != 0 || lhs.offset != 0)
- insert_into_complex (lhsvar, c);
- else
- add_graph_edge (graph, lhs.var, rhs.var);
- }
+ /* x = y */
+ add_pred_graph_edge (graph, lhsvar, rhsvar);
+ /* Implicitly, *x = *y */
+ add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
+ FIRST_REF_NODE + rhsvar);
+ }
+ else if (lhs.offset != 0 || rhs.offset != 0)
+ {
+ if (rhs.offset != 0)
+ RESET_BIT (graph->direct_nodes, lhs.var);
+ if (lhs.offset != 0)
+ RESET_BIT (graph->direct_nodes, rhs.var);
+ }
+ }
+}
+/* Build the constraint graph, adding successor edges. */
+
+static void
+build_succ_graph (void)
+{
+ int i;
+ constraint_t c;
+
+ for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
+ {
+ struct constraint_expr lhs;
+ struct constraint_expr rhs;
+ unsigned int lhsvar;
+ unsigned int rhsvar;
+
+ if (!c)
+ continue;
+
+ lhs = c->lhs;
+ rhs = c->rhs;
+ lhsvar = find (get_varinfo_fc (lhs.var)->id);
+ rhsvar = find (get_varinfo_fc (rhs.var)->id);
+
+ if (lhs.type == DEREF)
+ {
+ if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
+ add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
+ }
+ else if (rhs.type == DEREF)
+ {
+ if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
+ add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
+ }
+ else if (rhs.type == ADDRESSOF)
+ {
+ /* x = &y */
+ gcc_assert (find (get_varinfo_fc (rhs.var)->id)
+ == get_varinfo_fc (rhs.var)->id);
+ bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
+ }
+ else if (lhsvar > anything_id
+ && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
+ {
+ add_graph_edge (graph, lhsvar, rhsvar);
}
}
}
struct scc_info
{
sbitmap visited;
- sbitmap in_component;
+ sbitmap roots;
+ unsigned int *dfs;
+ unsigned int *node_mapping;
int current_index;
- unsigned int *visited_index;
VEC(unsigned,heap) *scc_stack;
- VEC(unsigned,heap) *unification_queue;
};
{
unsigned int i;
bitmap_iterator bi;
+ unsigned int my_dfs;
- 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 ++;
+ si->dfs[n] = si->current_index ++;
+ my_dfs = si->dfs[n];
/* Visit all the successors. */
EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
{
- unsigned int w = i;
+ unsigned int w;
+
+ if (i > LAST_REF_NODE)
+ break;
+
+ w = find (i);
+ if (TEST_BIT (si->roots, w))
+ continue;
+
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;
- }
+ {
+ unsigned int t = find (w);
+ unsigned int nnode = find (n);
+ gcc_assert (nnode == n);
+
+ if (si->dfs[t] < si->dfs[nnode])
+ si->dfs[n] = si->dfs[t];
+ }
}
/* See if any components have been identified. */
- if (get_varinfo (n)->node == n)
+ if (si->dfs[n] == my_dfs)
{
- 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)])
+ if (VEC_length (unsigned, si->scc_stack) > 0
+ && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
{
- 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);
-}
-
+ bitmap scc = BITMAP_ALLOC (NULL);
+ bool have_ref_node = n >= FIRST_REF_NODE;
+ unsigned int lowest_node;
+ bitmap_iterator bi;
-/* Collapse two variables into one variable, merging solutions if
- requested. */
+ bitmap_set_bit (scc, n);
-static void
-collapse_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
- bool merge_solutions)
-{
- bitmap tosol, fromsol;
+ while (VEC_length (unsigned, si->scc_stack) != 0
+ && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
+ {
+ unsigned int w = VEC_pop (unsigned, si->scc_stack);
- merge_graph_nodes (graph, to, from);
- condense_varmap_nodes (to, from);
- if (merge_solutions)
- {
- tosol = get_varinfo (to)->solution;
- fromsol = get_varinfo (from)->solution;
- bitmap_ior_into (tosol, fromsol);
- BITMAP_FREE (fromsol);
- }
+ bitmap_set_bit (scc, w);
+ if (w >= FIRST_REF_NODE)
+ have_ref_node = true;
+ }
- if (valid_graph_edge (graph, to, to))
- {
- if (graph->preds[to])
- {
- bitmap_clear_bit (graph->preds[to], to);
- bitmap_clear_bit (graph->succs[to], to);
+ lowest_node = bitmap_first_set_bit (scc);
+ gcc_assert (lowest_node < FIRST_REF_NODE);
+ EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
+ {
+ if (i < FIRST_REF_NODE)
+ {
+ /* Mark this node for collapsing. */
+ if (unite (lowest_node, i))
+ unify_nodes (graph, lowest_node, i, false);
+ }
+ else
+ {
+ unite (lowest_node, i);
+ graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
+ }
+ }
}
+ SET_BIT (si->roots, n);
}
+ else
+ VEC_safe_push (unsigned, heap, si->scc_stack, n);
}
-
-/* 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. */
+/* Unify node FROM into node TO, updating the changed count if
+ necessary when UPDATE_CHANGED is true. */
static void
-process_unification_queue (constraint_graph_t graph, struct scc_info *si,
- bool update_changed)
+unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
+ bool update_changed)
{
- size_t i = 0;
- bitmap tmp = BITMAP_ALLOC (update_changed ? &iteration_obstack : NULL);
- bitmap_clear (tmp);
- /* We proceed as follows:
+ gcc_assert (to != from && find (to) == to);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Unifying %s to %s\n",
+ get_varinfo (from)->name,
+ get_varinfo (to)->name);
- 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
+ if (update_changed)
+ stats.unified_vars_dynamic++;
+ else
+ stats.unified_vars_static++;
- update changed count to note that tounify will never change
- again
+ merge_graph_nodes (graph, to, from);
+ merge_node_constraints (graph, to, from);
- Merge tmp into solution for rep, marking rep changed if this
- changed rep's solution.
+ if (get_varinfo (from)->no_tbaa_pruning)
+ get_varinfo (to)->no_tbaa_pruning = true;
- Delete any self-edges we now have for rep. */
- while (i != VEC_length (unsigned, si->unification_queue))
+ if (update_changed && TEST_BIT (changed, from))
{
- 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++;
+ RESET_BIT (changed, from);
+ if (!TEST_BIT (changed, to))
+ SET_BIT (changed, to);
else
- stats.unified_vars_static++;
- bitmap_ior_into (tmp, get_varinfo (tounify)->solution);
- collapse_nodes (graph, n, tounify, false);
+ {
+ gcc_assert (changed_count > 0);
+ changed_count--;
+ }
+ }
- if (update_changed && TEST_BIT (changed, tounify))
+ /* If the solution changes because of the merging, we need to mark
+ the variable as changed. */
+ if (bitmap_ior_into (get_varinfo (to)->solution,
+ get_varinfo (from)->solution))
+ {
+ if (update_changed && !TEST_BIT (changed, to))
{
- RESET_BIT (changed, tounify);
- if (!TEST_BIT (changed, n))
- SET_BIT (changed, n);
- else
- {
- gcc_assert (changed_count > 0);
- changed_count--;
- }
+ SET_BIT (changed, to);
+ changed_count++;
}
+ }
- bitmap_clear (get_varinfo (tounify)->solution);
- ++i;
+ BITMAP_FREE (get_varinfo (from)->solution);
+ BITMAP_FREE (get_varinfo (from)->oldsolution);
- /* 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 (stats.iterations > 0)
+ {
+ BITMAP_FREE (get_varinfo (to)->oldsolution);
+ get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
+ }
- if (valid_graph_edge (graph, n, n))
- {
- if (graph->succs[n])
- {
- if (graph->preds[n])
- bitmap_clear_bit (graph->preds[n], n);
- bitmap_clear_bit (graph->succs[n], n);
- }
- }
- }
+ if (valid_graph_edge (graph, to, to))
+ {
+ if (graph->succs[to])
+ bitmap_clear_bit (graph->succs[to], to);
}
- BITMAP_FREE (tmp);
}
-
/* Information needed to compute the topological ordering of a graph. */
struct topo_info
topo_visit (constraint_graph_t graph, struct topo_info *ti,
unsigned int n)
{
- bitmap temp;
bitmap_iterator bi;
unsigned int j;
SET_BIT (ti->visited, n);
- temp = graph->succs[n];
- if (temp)
- EXECUTE_IF_SET_IN_BITMAP (temp, 0, j, bi)
+ if (graph->succs[n])
+ EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
{
if (!TEST_BIT (ti->visited, j))
topo_visit (graph, ti, j);
}
+
VEC_safe_push (unsigned, heap, ti->topo_order, n);
}
v = first_vi_for_offset (get_varinfo (j), fieldoffset);
if (!v)
continue;
- t = v->node;
+ t = find (v->id);
sol = get_varinfo (t)->solution;
if (!bitmap_bit_p (sol, rhs))
{
do_sd_constraint (constraint_graph_t graph, constraint_t c,
bitmap delta)
{
- unsigned int lhs = get_varinfo (c->lhs.var)->node;
+ unsigned int lhs = find (c->lhs.var);
bool flag = false;
bitmap sol = get_varinfo (lhs)->solution;
unsigned int j;
v = first_vi_for_offset (get_varinfo (j), fieldoffset);
if (!v)
continue;
- t = v->node;
+ t = find (v->id);
/* Adding edges from the special vars is pointless.
They don't have sets that can change. */
static void
do_ds_constraint (constraint_t c, bitmap delta)
{
- unsigned int rhs = get_varinfo (c->rhs.var)->node;
+ unsigned int rhs = find (c->rhs.var);
unsigned HOST_WIDE_INT roff = c->rhs.offset;
bitmap sol = get_varinfo (rhs)->solution;
unsigned int j;
v = first_vi_for_offset (get_varinfo (j), fieldoffset);
if (!v)
continue;
- t = v->node;
+ t = find (v->id);
if (!bitmap_bit_p (get_varinfo (t)->solution, anything_id))
{
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))
+ if (type_safe (j, &loff) && !(get_varinfo (j)->is_special_var))
{
varinfo_t v;
unsigned int t;
v = first_vi_for_offset (get_varinfo (j), fieldoffset);
if (!v)
continue;
- t = v->node;
+ t = find (v->id);
tmp = get_varinfo (t)->solution;
if (set_union_with_increment (tmp, sol, roff))
}
}
-/* Handle a non-simple (simple meaning requires no iteration), non-copy
- constraint (IE *x = &y, x = *y, and *x = y). */
+/* Handle a non-simple (simple meaning requires no iteration),
+ constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
static void
do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
bool flag = false;
unsigned int t;
- gcc_assert(c->rhs.type == SCALAR && c->lhs.type == SCALAR);
- t = get_varinfo (c->rhs.var)->node;
+ gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
+ t = find (c->rhs.var);
solution = get_varinfo (t)->solution;
- t = get_varinfo (c->lhs.var)->node;
+ t = find (c->lhs.var);
tmp = get_varinfo (t)->solution;
flag = set_union_with_increment (tmp, solution, c->rhs.offset);
if (flag)
{
get_varinfo (t)->solution = tmp;
- if (!TEST_BIT (changed, c->lhs.var))
+ if (!TEST_BIT (changed, t))
{
- SET_BIT (changed, c->lhs.var);
+ SET_BIT (changed, t);
changed_count++;
}
}
/* Initialize and return a new SCC info structure. */
static struct scc_info *
-init_scc_info (void)
+init_scc_info (size_t size)
{
struct scc_info *si = XNEW (struct scc_info);
- size_t size = VEC_length (varinfo_t, varmap);
+ size_t i;
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->roots = sbitmap_alloc (size);
+ sbitmap_zero (si->roots);
+ si->node_mapping = XNEWVEC (unsigned int, size);
+ si->dfs = XCNEWVEC (unsigned int, size);
+
+ for (i = 0; i < size; i++)
+ si->node_mapping[i] = i;
+
si->scc_stack = VEC_alloc (unsigned, heap, 1);
- si->unification_queue = VEC_alloc (unsigned, heap, 1);
return si;
}
free_scc_info (struct scc_info *si)
{
sbitmap_free (si->visited);
- sbitmap_free (si->in_component);
- free (si->visited_index);
+ sbitmap_free (si->roots);
+ free (si->node_mapping);
+ free (si->dfs);
VEC_free (unsigned, heap, si->scc_stack);
- VEC_free (unsigned, heap, si->unification_queue);
- free(si);
+ 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. */
+/* Find indirect cycles in GRAPH that occur, using strongly connected
+ components, and note them in the indirect cycles map.
+
+ This technique comes from Ben Hardekopf and Calvin Lin,
+ "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
+ Lines of Code", submitted to PLDI 2007. */
static void
-find_and_collapse_graph_cycles (constraint_graph_t graph, bool update_changed)
+find_indirect_cycles (constraint_graph_t graph)
{
unsigned int i;
- unsigned int size = VEC_length (varinfo_t, varmap);
- struct scc_info *si = init_scc_info ();
+ unsigned int size = graph->size;
+ struct scc_info *si = init_scc_info (size);
- for (i = 0; i != size; ++i)
- if (!TEST_BIT (si->visited, i) && get_varinfo (i)->node == i)
+ for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
+ if (!TEST_BIT (si->visited, i) && find (i) == i)
scc_visit (graph, si, i);
- process_unification_queue (graph, si, update_changed);
free_scc_info (si);
}
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)
+ if (!TEST_BIT (ti->visited, i) && find (i) == i)
topo_visit (graph, ti, i);
}
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. */
+ in "ACM SIGPLAN Notices" volume 35, number 5, pages 47-56.
+
+ There is an optimal way to do this involving hash based value
+ numbering, once the technique is published i will implement it
+ here.
+
+ The general method of finding equivalence classes is as follows:
+ Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
+ Add fake nodes (ADDRESS nodes) and edges for a = &b constraints.
+ Initialize all non-REF/ADDRESS nodes to be direct nodes
+ For each SCC in the predecessor graph:
+ for each member (x) of the SCC
+ if x is not a direct node:
+ set rootnode(SCC) to be not a direct node
+ collapse node x into rootnode(SCC).
+ if rootnode(SCC) is not a direct node:
+ label rootnode(SCC) with a new equivalence class
+ else:
+ if all labeled predecessors of rootnode(SCC) have the same
+ label:
+ label rootnode(SCC) with this label
+ else:
+ label rootnode(SCC) with a new equivalence class
+
+ All direct nodes with the same equivalence class can be replaced
+ with a single representative node.
+ All unlabeled nodes (label == 0) are not pointers and all edges
+ involving them can be eliminated.
+ We perform these optimizations during move_complex_constraints.
+*/
+
+static int equivalence_class;
+
+/* Recursive routine to find strongly connected components in GRAPH,
+ and label it's nodes with equivalence classes.
+ This is used during variable substitution to find cycles involving
+ the regular or implicit predecessors, and label them as equivalent.
+ The SCC finding algorithm used is the same as that for scc_visit. */
static void
+label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
+{
+ unsigned int i;
+ bitmap_iterator bi;
+ unsigned int my_dfs;
+
+ gcc_assert (si->node_mapping[n] == n);
+ SET_BIT (si->visited, n);
+ si->dfs[n] = si->current_index ++;
+ my_dfs = si->dfs[n];
+
+ /* Visit all the successors. */
+ EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
+ {
+ unsigned int w = si->node_mapping[i];
+
+ if (TEST_BIT (si->roots, w))
+ continue;
+
+ if (!TEST_BIT (si->visited, w))
+ label_visit (graph, si, w);
+ {
+ unsigned int t = si->node_mapping[w];
+ unsigned int nnode = si->node_mapping[n];
+ gcc_assert (nnode == n);
+
+ if (si->dfs[t] < si->dfs[nnode])
+ si->dfs[n] = si->dfs[t];
+ }
+ }
+
+ /* Visit all the implicit predecessors. */
+ EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
+ {
+ unsigned int w = si->node_mapping[i];
+
+ if (TEST_BIT (si->roots, w))
+ continue;
+
+ if (!TEST_BIT (si->visited, w))
+ label_visit (graph, si, w);
+ {
+ unsigned int t = si->node_mapping[w];
+ unsigned int nnode = si->node_mapping[n];
+ gcc_assert (nnode == n);
+
+ if (si->dfs[t] < si->dfs[nnode])
+ si->dfs[n] = si->dfs[t];
+ }
+ }
+
+ /* See if any components have been identified. */
+ if (si->dfs[n] == my_dfs)
+ {
+ while (VEC_length (unsigned, si->scc_stack) != 0
+ && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
+ {
+ unsigned int w = VEC_pop (unsigned, si->scc_stack);
+ si->node_mapping[w] = n;
+
+ if (!TEST_BIT (graph->direct_nodes, w))
+ RESET_BIT (graph->direct_nodes, n);
+ }
+ SET_BIT (si->roots, n);
+
+ if (!TEST_BIT (graph->direct_nodes, n))
+ {
+ graph->label[n] = equivalence_class++;
+ }
+ else
+ {
+ unsigned int size = 0;
+ unsigned int firstlabel = ~0;
+
+ EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
+ {
+ unsigned int j = si->node_mapping[i];
+
+ if (j == n || graph->label[j] == 0)
+ continue;
+
+ if (firstlabel == (unsigned int)~0)
+ {
+ firstlabel = graph->label[j];
+ size++;
+ }
+ else if (graph->label[j] != firstlabel)
+ size++;
+ }
+
+ if (size == 0)
+ graph->label[n] = 0;
+ else if (size == 1)
+ graph->label[n] = firstlabel;
+ else
+ graph->label[n] = equivalence_class++;
+ }
+ }
+ else
+ VEC_safe_push (unsigned, heap, si->scc_stack, n);
+}
+
+/* Perform offline variable substitution, discovering equivalence
+ classes, and eliminating non-pointer variables. */
+
+static struct scc_info *
perform_var_substitution (constraint_graph_t graph)
{
- struct topo_info *ti = init_topo_info ();
+ unsigned int i;
+ unsigned int size = graph->size;
+ struct scc_info *si = init_scc_info (size);
bitmap_obstack_initialize (&iteration_obstack);
- /* Compute the topological ordering of the graph, then visit each
- node in topological order. */
- compute_topo_order (graph, ti);
+ equivalence_class = 0;
+
+ /* We only need to visit the non-address nodes for labeling
+ purposes, as the address nodes will never have any predecessors,
+ because &x never appears on the LHS of a constraint. */
+ for (i = 0; i < LAST_REF_NODE; i++)
+ if (!TEST_BIT (si->visited, si->node_mapping[i]))
+ label_visit (graph, si, si->node_mapping[i]);
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ for (i = 0; i < FIRST_REF_NODE; i++)
+ {
+ bool direct_node = TEST_BIT (graph->direct_nodes, i);
+ fprintf (dump_file,
+ "Equivalence class for %s node id %d:%s is %d\n",
+ direct_node ? "Direct node" : "Indirect node", i,
+ get_varinfo (i)->name,
+ graph->label[si->node_mapping[i]]);
+ }
- while (VEC_length (unsigned, ti->topo_order) != 0)
+ /* Quickly eliminate our non-pointer variables. */
+
+ for (i = 0; i < FIRST_REF_NODE; i++)
{
- unsigned int i = VEC_pop (unsigned, ti->topo_order);
- varinfo_t vi = get_varinfo (i);
- bool okay_to_elim = false;
- unsigned int root = VEC_length (varinfo_t, varmap);
- bitmap tmp;
- unsigned int k;
- bitmap_iterator bi;
+ unsigned int node = si->node_mapping[i];
- /* 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;
+ if (graph->label[node] == 0 && TEST_BIT (graph->direct_nodes, node))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file,
+ "%s is a non-pointer variable, eliminating edges.\n",
+ get_varinfo (node)->name);
+ stats.nonpointer_vars++;
+ clear_edges_for_node (graph, node);
+ }
+ }
+ return si;
+}
- /* See if all predecessors of I are ripe for elimination */
- EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[i], 0, k, bi)
- {
- unsigned int w;
- w = get_varinfo (k)->node;
+/* Free information that was only necessary for variable
+ substitution. */
- /* 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;
- }
+static void
+free_var_substitution_info (struct scc_info *si)
+{
+ free_scc_info (si);
+ free (graph->label);
+ free (graph->eq_rep);
+ sbitmap_free (graph->direct_nodes);
+ bitmap_obstack_release (&iteration_obstack);
+}
- /* 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);
- }
+/* Return an existing node that is equivalent to NODE, which has
+ equivalence class LABEL, if one exists. Return NODE otherwise. */
+
+static unsigned int
+find_equivalent_node (constraint_graph_t graph,
+ unsigned int node, unsigned int label)
+{
+ /* If the address version of this variable is unused, we can
+ substitute it for anything else with the same label.
+ Otherwise, we know the pointers are equivalent, but not the
+ locations. */
+
+ if (graph->label[FIRST_ADDR_NODE + node] == 0)
+ {
+ gcc_assert (label < graph->size);
+
+ if (graph->eq_rep[label] != -1)
+ {
+ /* Unify the two variables since we know they are equivalent. */
+ if (unite (graph->eq_rep[label], node))
+ unify_nodes (graph, graph->eq_rep[label], node, false);
+ return graph->eq_rep[label];
+ }
+ else
+ {
+ graph->eq_rep[label] = node;
+ }
+ }
+ return node;
+}
+
+/* Move complex constraints to the appropriate nodes, and collapse
+ variables we've discovered are equivalent during variable
+ substitution. SI is the SCC_INFO that is the result of
+ perform_variable_substitution. */
+
+static void
+move_complex_constraints (constraint_graph_t graph,
+ struct scc_info *si)
+{
+ int i;
+ unsigned int j;
+ constraint_t c;
+
+ for (j = 0; j < graph->size; j++)
+ gcc_assert (find (j) == j);
+
+ 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 = find (get_varinfo_fc (lhs.var)->id);
+ unsigned int rhsvar = find (get_varinfo_fc (rhs.var)->id);
+ unsigned int lhsnode, rhsnode;
+ unsigned int lhslabel, rhslabel;
+
+ lhsnode = si->node_mapping[lhsvar];
+ rhsnode = si->node_mapping[rhsvar];
+ lhslabel = graph->label[lhsnode];
+ rhslabel = graph->label[rhsnode];
+
+ /* See if it is really a non-pointer variable, and if so, ignore
+ the constraint. */
+ if (lhslabel == 0)
+ {
+ if (!TEST_BIT (graph->direct_nodes, lhsnode))
+ lhslabel = graph->label[lhsnode] = equivalence_class++;
+ else
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+
+ fprintf (dump_file, "%s is a non-pointer variable,"
+ "ignoring constraint:",
+ get_varinfo (lhs.var)->name);
+ dump_constraint (dump_file, c);
+ }
+ VEC_replace (constraint_t, constraints, i, NULL);
+ continue;
+ }
+ }
+
+ if (rhslabel == 0)
+ {
+ if (!TEST_BIT (graph->direct_nodes, rhsnode))
+ rhslabel = graph->label[rhsnode] = equivalence_class++;
+ else
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+
+ fprintf (dump_file, "%s is a non-pointer variable,"
+ "ignoring constraint:",
+ get_varinfo (rhs.var)->name);
+ dump_constraint (dump_file, c);
+ }
+ VEC_replace (constraint_t, constraints, i, NULL);
+ continue;
+ }
+ }
+
+ lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
+ rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
+ c->lhs.var = lhsvar;
+ c->rhs.var = rhsvar;
+
+ if (lhs.type == DEREF)
+ {
+ if (rhs.type == ADDRESSOF || rhsvar > anything_id)
+ insert_into_complex (graph, lhsvar, c);
+ }
+ else if (rhs.type == DEREF)
+ {
+ if (!(get_varinfo (lhsvar)->is_special_var))
+ insert_into_complex (graph, rhsvar, c);
+ }
+ else if (rhs.type != ADDRESSOF && lhsvar > anything_id
+ && (lhs.offset != 0 || rhs.offset != 0))
+ {
+ insert_into_complex (graph, rhsvar, c);
+ }
+
+ }
+}
+
+/* Eliminate indirect cycles involving NODE. Return true if NODE was
+ part of an SCC, false otherwise. */
+
+static bool
+eliminate_indirect_cycles (unsigned int node)
+{
+ if (graph->indirect_cycles[node] != -1
+ && !bitmap_empty_p (get_varinfo (node)->solution))
+ {
+ unsigned int i;
+ VEC(unsigned,heap) *queue = NULL;
+ int queuepos;
+ unsigned int to = find (graph->indirect_cycles[node]);
+ bitmap_iterator bi;
+
+ /* We can't touch the solution set and call unify_nodes
+ at the same time, because unify_nodes is going to do
+ bitmap unions into it. */
- /* 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)
+ EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
{
- /* Found an equivalence */
- get_varinfo (i)->node = root;
- collapse_nodes (graph, root, i, true);
- 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++;
+ if (find (i) == i && i != to)
+ {
+ if (unite (to, i))
+ VEC_safe_push (unsigned, heap, queue, i);
+ }
}
- }
- bitmap_obstack_release (&iteration_obstack);
- free_topo_info (ti);
+ for (queuepos = 0;
+ VEC_iterate (unsigned, queue, queuepos, i);
+ queuepos++)
+ {
+ unify_nodes (graph, to, i, true);
+ }
+ VEC_free (unsigned, heap, queue);
+ return true;
+ }
+ return false;
}
/* Solve the constraint graph GRAPH using our worklist solver.
{
unsigned int size = VEC_length (varinfo_t, varmap);
unsigned int i;
+ bitmap pts;
- changed_count = size;
+ changed_count = 0;
changed = sbitmap_alloc (size);
- sbitmap_ones (changed);
+ sbitmap_zero (changed);
- /* The already collapsed/unreachable nodes will never change, so we
- need to account for them in changed_count. */
+ /* Mark all initial non-collapsed nodes as changed. */
for (i = 0; i < size; i++)
- if (get_varinfo (i)->node != i)
- changed_count--;
+ {
+ varinfo_t ivi = get_varinfo (i);
+ if (find (i) == i && !bitmap_empty_p (ivi->solution)
+ && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
+ || VEC_length (constraint_t, graph->complex[i]) > 0))
+ {
+ SET_BIT (changed, i);
+ changed_count++;
+ }
+ }
+
+ /* Allocate a bitmap to be used to store the changed bits. */
+ pts = BITMAP_ALLOC (&pta_obstack);
while (changed_count > 0)
{
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 this variable is not a representative, skip it. */
+ if (find (i) != i)
+ continue;
+
+ /* In certain indirect cycle cases, we may merge this
+ variable to another. */
+ if (eliminate_indirect_cycles (i) && find (i) != i)
+ continue;
/* If the node has changed, we need to process the
complex constraints and outgoing edges again. */
unsigned int j;
constraint_t c;
bitmap solution;
- bitmap_iterator bi;
- VEC(constraint_t,heap) *complex = get_varinfo (i)->complex;
+ VEC(constraint_t,heap) *complex = graph->complex[i];
bool solution_empty;
RESET_BIT (changed, i);
changed_count--;
+ /* Compute the changed set of solution bits. */
+ bitmap_and_compl (pts, get_varinfo (i)->solution,
+ get_varinfo (i)->oldsolution);
+
+ if (bitmap_empty_p (pts))
+ continue;
+
+ bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
+
solution = get_varinfo (i)->solution;
solution_empty = bitmap_empty_p (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);
+ do_complex_constraint (graph, c, pts);
}
solution_empty = bitmap_empty_p (solution);
if (!solution_empty)
{
+ bitmap_iterator bi;
+
/* Propagate solution to all successors. */
EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
0, j, bi)
{
- bitmap tmp = get_varinfo (j)->solution;
- bool flag = false;
+ bitmap tmp;
+ bool flag;
+
+ unsigned int to = find (j);
+ tmp = get_varinfo (to)->solution;
+ flag = false;
- gcc_assert (get_varinfo (j)->node == j);
+ /* Don't try to propagate to ourselves. */
+ if (to == i)
+ continue;
- flag = set_union_with_increment (tmp, solution, 0);
+ flag = set_union_with_increment (tmp, pts, 0);
if (flag)
{
- get_varinfo (j)->solution = tmp;
- if (!TEST_BIT (changed, j))
+ get_varinfo (to)->solution = tmp;
+ if (!TEST_BIT (changed, to))
{
- SET_BIT (changed, j);
+ SET_BIT (changed, to);
changed_count++;
}
}
bitmap_obstack_release (&iteration_obstack);
}
+ BITMAP_FREE (pts);
sbitmap_free (changed);
+ bitmap_obstack_release (&oldpta_obstack);
}
+/* Map from trees to variable infos. */
+static struct pointer_map_t *vi_for_tree;
-/* 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. */
+/* Insert ID as the variable id for tree T in the vi_for_tree map. */
static void
-insert_id_for_tree (tree t, int id)
+insert_vi_for_tree (tree t, varinfo_t vi)
{
- void **slot;
- struct tree_id finder;
- tree_id_t new_pair;
-
- finder.t = t;
- slot = htab_find_slot (id_for_tree, &finder, INSERT);
+ void **slot = pointer_map_insert (vi_for_tree, t);
+ gcc_assert (vi);
gcc_assert (*slot == NULL);
- new_pair = XNEW (struct tree_id);
- new_pair->t = t;
- new_pair->id = id;
- *slot = (void *)new_pair;
+ *slot = vi;
}
-/* 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. */
+/* Find the variable info for tree T in VI_FOR_TREE. If T does not
+ exist in the map, return NULL, otherwise, return the varinfo we found. */
-static bool
-lookup_id_for_tree (tree t, unsigned int *id)
+static varinfo_t
+lookup_vi_for_tree (tree t)
{
- tree_id_t pair;
- struct tree_id finder;
+ void **slot = pointer_map_contains (vi_for_tree, t);
+ if (slot == NULL)
+ return NULL;
- finder.t = t;
- pair = htab_find (id_for_tree, &finder);
- if (pair == NULL)
- return false;
- *id = pair->id;
- return true;
+ return (varinfo_t) *slot;
}
/* Return a printable name for DECL */
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. */
+/* Find the variable id for tree T in the map.
+ If T doesn't exist in the map, create an entry for it and return it. */
-static unsigned int
-get_id_for_tree (tree t)
+static varinfo_t
+get_vi_for_tree (tree t)
{
- tree_id_t pair;
- struct tree_id finder;
+ void **slot = pointer_map_contains (vi_for_tree, t);
+ if (slot == NULL)
+ return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
- 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;
+ return (varinfo_t) *slot;
}
/* Get a constraint expression from an SSA_VAR_P node. */
decl. */
if (TREE_CODE (t) == SSA_NAME
&& TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
- && gimple_default_def (cfun, SSA_NAME_VAR (t)) == t)
+ && SSA_NAME_IS_DEFAULT_DEF (t))
return get_constraint_exp_from_ssa_var (SSA_NAME_VAR (t));
cexpr.type = SCALAR;
- cexpr.var = get_id_for_tree (t);
+ cexpr.var = get_vi_for_tree (t)->id;
/* 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 = INCLUDES;
+ cexpr.type = ADDRESSOF;
cexpr.var = readonly_id;
}
gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
- gcc_assert (lhs.type != INCLUDES);
-
if (lhs.type == DEREF)
get_varinfo (lhs.var)->directly_dereferenced = true;
if (rhs.type == DEREF)
return;
/* If we have &ANYTHING = something, convert to SOMETHING = &ANYTHING) */
- else if (lhs.var == anything_id
- && (lhs.type == INCLUDES || lhs.type == ADDRESSOF))
+ else if (lhs.var == anything_id && lhs.type == ADDRESSOF)
{
rhs = t->lhs;
t->lhs = t->rhs;
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);
-
- 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;
+ gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
VEC_safe_push (constraint_t, heap, constraints, t);
}
}
{
tree type = TREE_TYPE (t);
- if (POINTER_TYPE_P (type) || AGGREGATE_TYPE_P (type)
+ if (POINTER_TYPE_P (type)
+ || AGGREGATE_TYPE_P (type)
|| TREE_CODE (type) == COMPLEX_TYPE)
return true;
+
return false;
}
switch (TREE_CODE_CLASS (TREE_CODE (t)))
{
case tcc_expression:
+ case tcc_vl_exp:
{
switch (TREE_CODE (t))
{
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)
vi = get_varinfo (temp.var);
vi->is_artificial_var = 1;
vi->is_heap_var = 1;
- temp.type = INCLUDES;
+ temp.type = ADDRESSOF;
temp.offset = 0;
VEC_safe_push (ce_s, heap, *results, &temp);
return;
}
/* Handle the structure copy case where we have a structure copy
- between a aggregate on the RHS and a dereference of a pointer on
+ between an 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)
}
}
+
/* 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
bitmap addr_taken;
use_operand_p use_p;
ssa_op_iter iter;
+ bool stmt_dereferences_ptr_p;
enum escape_type stmt_escape_type = is_escape_site (stmt);
- tree op;
+ struct mem_ref_stats_d *mem_ref_stats = gimple_mem_ref_stats (cfun);
+
+ stmt_dereferences_ptr_p = false;
if (stmt_escape_type == ESCAPE_TO_CALL
|| stmt_escape_type == ESCAPE_TO_PURE_CONST)
{
- ai->num_calls_found++;
+ mem_ref_stats->num_call_sites++;
if (stmt_escape_type == ESCAPE_TO_PURE_CONST)
- ai->num_pure_const_calls_found++;
+ mem_ref_stats->num_pure_const_call_sites++;
}
+ else if (stmt_escape_type == ESCAPE_TO_ASM)
+ mem_ref_stats->num_asm_sites++;
/* Mark all the variables whose address are taken by the statement. */
addr_taken = addresses_taken (stmt);
}
}
- /* 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. */
+ /* Process each operand use. 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;
+ unsigned num_uses, num_loads, num_stores;
op = USE_FROM_PTR (use_p);
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);
+ add_to_addressable_set (TREE_OPERAND (op, 0), &addressable_vars);
continue;
}
- /* Ignore constants. */
+ /* Ignore constants (they may occur in PHI node arguments). */
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
+ /* The base variable of an SSA name must be a GIMPLE register, and thus
it cannot be aliased. */
gcc_assert (!may_be_aliased (var));
/* 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);
+ count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
/* Handle a corner case involving address expressions of the
form '&PTR->FLD'. The problem with these expressions is that
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.
+ memory operations will receive no VDEF/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
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 (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
+ && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ADDR_EXPR
+ && !is_gimple_val (GIMPLE_STMT_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 rhs = GIMPLE_STMT_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;
+ num_loads++;
}
- if (num_derefs > 0 || is_potential_deref)
+ if (num_loads + num_stores > 0)
{
/* Mark OP as dereferenced. In a subsequent pass,
dereferenced pointers that point to a set of
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));
+ if (num_stores > 0)
+ pointer_set_insert (ai->dereferenced_ptrs_store, var);
else
- bitmap_set_bit (ai->dereferenced_ptrs_load, DECL_UID (var));
+ pointer_set_insert (ai->dereferenced_ptrs_load, var);
+
+ /* Update the frequency estimate for all the dereferences of
+ pointer OP. */
+ update_mem_sym_stats_from_stmt (op, stmt, num_loads, num_stores);
+
+ /* Indicate that STMT contains pointer dereferences. */
+ stmt_dereferences_ptr_p = true;
}
- if (stmt_escape_type != NO_ESCAPE && num_derefs < num_uses)
+ if (stmt_escape_type != NO_ESCAPE && num_loads + num_stores < num_uses)
{
/* If STMT is an escape point and STMT contains at
least one direct use of OP, then the value of OP
if (get_call_expr_in (stmt)
|| stmt_escape_type == ESCAPE_STORED_IN_GLOBAL)
{
- bitmap_set_bit (ai->dereferenced_ptrs_store, DECL_UID (var));
+ pointer_set_insert (ai->dereferenced_ptrs_store, 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)
+ /* Mark stored variables in STMT as being written to and update the
+ memory reference stats for all memory symbols referenced by STMT. */
+ if (stmt_references_memory_p (stmt))
{
- 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);
+ unsigned i;
+ bitmap_iterator bi;
- }
+ mem_ref_stats->num_mem_stmts++;
+
+ /* Notice that we only update memory reference stats for symbols
+ loaded and stored by the statement if the statement does not
+ contain pointer dereferences and it is not a call/asm site.
+ This is to avoid double accounting problems when creating
+ memory partitions. After computing points-to information,
+ pointer dereference statistics are used to update the
+ reference stats of the pointed-to variables, so here we
+ should only update direct references to symbols.
+
+ Indirect references are not updated here for two reasons: (1)
+ The first time we compute alias information, the sets
+ LOADED/STORED are empty for pointer dereferences, (2) After
+ partitioning, LOADED/STORED may have references to
+ partitions, not the original pointed-to variables. So, if we
+ always counted LOADED/STORED here and during partitioning, we
+ would count many symbols more than once.
+
+ This does cause some imprecision when a statement has a
+ combination of direct symbol references and pointer
+ dereferences (e.g., MEMORY_VAR = *PTR) or if a call site has
+ memory symbols in its argument list, but these cases do not
+ occur so frequently as to constitute a serious problem. */
+ if (STORED_SYMS (stmt))
+ EXECUTE_IF_SET_IN_BITMAP (STORED_SYMS (stmt), 0, i, bi)
+ {
+ tree sym = referenced_var (i);
+ pointer_set_insert (ai->written_vars, sym);
+ if (!stmt_dereferences_ptr_p
+ && stmt_escape_type != ESCAPE_TO_CALL
+ && stmt_escape_type != ESCAPE_TO_PURE_CONST
+ && stmt_escape_type != ESCAPE_TO_ASM)
+ update_mem_sym_stats_from_stmt (sym, stmt, 0, 1);
+ }
- /* 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));
+ if (!stmt_dereferences_ptr_p
+ && LOADED_SYMS (stmt)
+ && stmt_escape_type != ESCAPE_TO_CALL
+ && stmt_escape_type != ESCAPE_TO_PURE_CONST
+ && stmt_escape_type != ESCAPE_TO_ASM)
+ EXECUTE_IF_SET_IN_BITMAP (LOADED_SYMS (stmt), 0, i, bi)
+ update_mem_sym_stats_from_stmt (referenced_var (i), stmt, 1, 0);
}
}
unsigned int i = 0;
unsigned int j = 0;
VEC (ce_s, heap) *temp = NULL;
- unsigned int rhsoffset = 0;
+ unsigned HOST_WIDE_INT rhsoffset = 0;
- if (TREE_CODE (expr) != PLUS_EXPR
- && TREE_CODE (expr) != MINUS_EXPR)
+ if (TREE_CODE (expr) != POINTER_PLUS_EXPR)
return false;
op0 = TREE_OPERAND (expr, 0);
op1 = TREE_OPERAND (expr, 1);
+ gcc_assert (POINTER_TYPE_P (TREE_TYPE (op0)));
get_constraint_for (op0, &temp);
- if (POINTER_TYPE_P (TREE_TYPE (op0))
- && TREE_CODE (op1) == INTEGER_CST
- && TREE_CODE (expr) == PLUS_EXPR)
+
+ /* We can only handle positive offsets that do not overflow
+ if we multiply it by BITS_PER_UNIT. */
+ if (host_integerp (op1, 1))
{
rhsoffset = TREE_INT_CST_LOW (op1) * BITS_PER_UNIT;
- }
+ if (rhsoffset / BITS_PER_UNIT != TREE_INT_CST_LOW (op1))
+ return false;
+ }
for (i = 0; VEC_iterate (ce_s, lhsc, i, c); i++)
for (j = 0; VEC_iterate (ce_s, temp, j, c2); j++)
}
}
/* 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. */
+ arguments through their calls. There are two cases, either a
+ GIMPLE_MODIFY_STMT 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))
+ && ((TREE_CODE (t) == GIMPLE_MODIFY_STMT
+ && TREE_CODE (GIMPLE_STMT_OPERAND (t, 1)) == CALL_EXPR
+ && !(call_expr_flags (GIMPLE_STMT_OPERAND (t, 1))
& (ECF_MALLOC | ECF_MAY_BE_ALLOCA)))
|| (TREE_CODE (t) == CALL_EXPR
&& !(call_expr_flags (t)
{
tree lhsop;
tree rhsop;
- unsigned int varid;
- tree arglist;
+ tree arg;
+ call_expr_arg_iterator iter;
varinfo_t fi;
int i = 1;
tree decl;
- if (TREE_CODE (t) == MODIFY_EXPR)
+ if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
{
- lhsop = TREE_OPERAND (t, 0);
- rhsop = TREE_OPERAND (t, 1);
+ lhsop = GIMPLE_STMT_OPERAND (t, 0);
+ rhsop = GIMPLE_STMT_OPERAND (t, 1);
}
else
{
we should still be able to handle. */
if (decl)
{
- varid = get_id_for_tree (decl);
+ fi = get_vi_for_tree (decl);
}
else
{
- decl = TREE_OPERAND (rhsop, 0);
- varid = get_id_for_tree (decl);
+ decl = CALL_EXPR_FN (rhsop);
+ fi = get_vi_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);
+ FOR_EACH_CALL_EXPR_ARG (arg, iter, rhsop)
+ {
struct constraint_expr lhs ;
struct constraint_expr *rhsp;
}
i++;
}
+
/* If we are returning a value, assign it to the result. */
if (lhsop)
{
}
}
/* Otherwise, just a regular assignment statement. */
- else if (TREE_CODE (t) == MODIFY_EXPR)
+ else if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
{
- tree lhsop = TREE_OPERAND (t, 0);
- tree rhsop = TREE_OPERAND (t, 1);
+ tree lhsop = GIMPLE_STMT_OPERAND (t, 0);
+ tree rhsop = GIMPLE_STMT_OPERAND (t, 1);
int i;
if ((AGGREGATE_TYPE_P (TREE_TYPE (lhsop))
case tcc_constant:
case tcc_exceptional:
case tcc_expression:
+ case tcc_vl_exp:
case tcc_unary:
{
unsigned int j;
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++)
+ for (i = 0; i < TREE_OPERAND_LENGTH (rhsop); i++)
{
tree op = TREE_OPERAND (rhsop, i);
unsigned int j;
}
}
}
+ else if (TREE_CODE (t) == CHANGE_DYNAMIC_TYPE_EXPR)
+ {
+ unsigned int j;
+
+ get_constraint_for (CHANGE_DYNAMIC_TYPE_LOCATION (t), &lhsc);
+ for (j = 0; VEC_iterate (ce_s, lhsc, j, c); ++j)
+ get_varinfo (c->var)->no_tbaa_pruning = true;
+ }
/* After promoting variables and computing aliasing we will
need to re-scan most statements. FIXME: Try to minimize the
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. */
+ TYPE. ADDRESSABLE_TYPE is the type of the outermost object that could have
+ its address taken. */
int
push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
- HOST_WIDE_INT offset, bool *has_union)
+ HOST_WIDE_INT offset, bool *has_union,
+ tree addressable_type)
{
tree field;
int count = 0;
real_part->size = TYPE_SIZE (TREE_TYPE (type));
real_part->offset = offset;
real_part->decl = NULL_TREE;
+ real_part->alias_set = -1;
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;
+ img_part->alias_set = -1;
return 2;
}
push = true;
else if (!(pushed = push_fields_onto_fieldstack
(TREE_TYPE (type), fieldstack,
- offset + i * TREE_INT_CST_LOW (elsz), has_union)))
+ offset + i * TREE_INT_CST_LOW (elsz), has_union,
+ TREE_TYPE (type))))
/* 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 */
pair->size = elsz;
pair->decl = NULL_TREE;
pair->offset = offset + i * TREE_INT_CST_LOW (elsz);
+ pair->alias_set = -1;
count++;
}
else
push = true;
else if (!(pushed = push_fields_onto_fieldstack
(TREE_TYPE (field), fieldstack,
- offset + bitpos_of_field (field), has_union))
+ offset + bitpos_of_field (field), has_union,
+ (DECL_NONADDRESSABLE_P (field)
+ ? addressable_type
+ : TREE_TYPE (field))))
&& DECL_SIZE (field)
&& !integer_zerop (DECL_SIZE (field)))
/* Empty structures may have actual size, like in C++. So
pair->size = DECL_SIZE (field);
pair->decl = field;
pair->offset = offset + bitpos_of_field (field);
+ if (DECL_NONADDRESSABLE_P (field))
+ pair->alias_set = get_alias_set (addressable_type);
+ else
+ pair->alias_set = -1;
count++;
}
else
rhs.var = anything_id;
rhs.offset = 0;
- rhs.type = INCLUDES;
+ rhs.type = ADDRESSOF;
process_constraint (new_constraint (lhs, rhs));
}
/* Create the variable info. */
- vi = new_var_info (decl, index, name, index);
+ vi = new_var_info (decl, index, name);
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);
+ insert_vi_for_tree (vi->decl, vi);
VEC_safe_push (varinfo_t, heap, varmap, vi);
stats.total_vars++;
newname = ggc_strdup (tempname);
free (tempname);
- argvi = new_var_info (argdecl, newindex,newname, newindex);
+ argvi = new_var_info (argdecl, newindex, newname);
argvi->decl = argdecl;
VEC_safe_push (varinfo_t, heap, varmap, argvi);
argvi->offset = i;
stats.total_vars ++;
if (arg)
{
- insert_id_for_tree (arg, newindex);
+ insert_vi_for_tree (arg, argvi);
arg = TREE_CHAIN (arg);
}
}
newname = ggc_strdup (tempname);
free (tempname);
- resultvi = new_var_info (resultdecl, newindex, newname, newindex);
+ resultvi = new_var_info (resultdecl, newindex, newname);
resultvi->decl = resultdecl;
VEC_safe_push (varinfo_t, heap, varmap, resultvi);
resultvi->offset = i;
insert_into_field_list_sorted (vi, resultvi);
stats.total_vars ++;
if (DECL_RESULT (decl))
- insert_id_for_tree (DECL_RESULT (decl), newindex);
+ insert_vi_for_tree (DECL_RESULT (decl), resultvi);
}
return index;
}
|| TREE_CODE (decltype) == QUAL_UNION_TYPE;
if (var_can_have_subvars (decl) && use_field_sensitive && !hasunion)
{
- push_fields_onto_fieldstack (decltype, &fieldstack, 0, &hasunion);
+ push_fields_onto_fieldstack (decltype, &fieldstack, 0, &hasunion,
+ decltype);
if (hasunion)
{
VEC_free (fieldoff_s, heap, fieldstack);
/* 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 = new_var_info (decl, index, name);
vi->decl = decl;
vi->offset = 0;
vi->has_union = hasunion;
vi->size = vi->fullsize;
}
- insert_id_for_tree (vi->decl, index);
+ insert_vi_for_tree (vi->decl, vi);
VEC_safe_push (varinfo_t, heap, varmap, vi);
if (is_global && (!flag_whole_program || !in_ipa_mode))
make_constraint_from_anything (vi);
newname = ggc_strdup (tempname);
free (tempname);
}
- newvi = new_var_info (decl, newindex, newname, newindex);
+ newvi = new_var_info (decl, newindex, newname);
newvi->offset = fo->offset;
newvi->size = TREE_INT_CST_LOW (fo->size);
newvi->fullsize = vi->fullsize;
unsigned int i;
bitmap_iterator bi;
- if (vi->node != var)
+ if (find (var) != var)
{
- varinfo_t vipt = get_varinfo (vi->node);
+ varinfo_t vipt = get_varinfo (find (var));
fprintf (file, "%s = same as %s\n", vi->name, vipt->name);
}
else
{
fprintf (file, "%s = { ", vi->name);
- EXECUTE_IF_SET_IN_BITMAP (get_varinfo (vi->node)->solution, 0, i, bi)
+ EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
{
fprintf (file, "%s ", get_varinfo (i)->name);
}
- fprintf (file, "}\n");
+ fprintf (file, "}");
+ if (vi->no_tbaa_pruning)
+ fprintf (file, " no-tbaa-pruning");
+ fprintf (file, "\n");
}
}
tree t;
struct constraint_expr lhs, rhs;
- /* For each incoming pointer argument arg, ARG = ANYTHING or a
- dummy variable if flag_argument_noalias > 2. */
+ /* For each incoming pointer argument arg, create the constraint ARG
+ = ANYTHING or a dummy variable if flag_argument_noalias is set. */
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)
+ /* If flag_argument_noalias is set, then function pointer
+ arguments are guaranteed not to point to each other. In that
+ case, create an artificial variable PARM_NOALIAS and the
+ constraint ARG = &PARM_NOALIAS. */
+ if (POINTER_TYPE_P (TREE_TYPE (t)) && flag_argument_noalias > 0)
{
varinfo_t vi;
tree heapvar = heapvar_lookup (t);
- unsigned int id;
lhs.offset = 0;
lhs.type = SCALAR;
- lhs.var = get_id_for_tree (t);
+ lhs.var = get_vi_for_tree (t)->id;
if (heapvar == NULL_TREE)
{
+ var_ann_t ann;
heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
"PARM_NOALIAS");
- get_var_ann (heapvar)->is_heapvar = 1;
DECL_EXTERNAL (heapvar) = 1;
if (gimple_referenced_vars (cfun))
add_referenced_var (heapvar);
+
heapvar_insert (t, heapvar);
+
+ ann = get_var_ann (heapvar);
+ if (flag_argument_noalias == 1)
+ ann->noalias_state = NO_ALIAS;
+ else if (flag_argument_noalias == 2)
+ ann->noalias_state = NO_ALIAS_GLOBAL;
+ else if (flag_argument_noalias == 3)
+ ann->noalias_state = NO_ALIAS_ANYTHING;
+ else
+ gcc_unreachable ();
}
- id = get_id_for_tree (heapvar);
- vi = get_varinfo (id);
+
+ vi = get_vi_for_tree (heapvar);
vi->is_artificial_var = 1;
vi->is_heap_var = 1;
- rhs.var = id;
- rhs.type = INCLUDES;
+ rhs.var = vi->id;
+ rhs.type = ADDRESSOF;
rhs.offset = 0;
for (p = get_varinfo (lhs.var); p; p = p->next)
{
}
else
{
- for (p = get_varinfo (arg_id); p; p = p->next)
+ varinfo_t arg_vi = get_vi_for_tree (t);
+
+ for (p = arg_vi; p; p = p->next)
make_constraint_from_anything (p);
}
}
}
+/* Structure used to put solution bitmaps in a hashtable so they can
+ be shared among variables with the same points-to set. */
+
+typedef struct shared_bitmap_info
+{
+ bitmap pt_vars;
+ hashval_t hashcode;
+} *shared_bitmap_info_t;
+
+static htab_t shared_bitmap_table;
+
+/* Hash function for a shared_bitmap_info_t */
+
+static hashval_t
+shared_bitmap_hash (const void *p)
+{
+ const shared_bitmap_info_t bi = (shared_bitmap_info_t) p;
+ return bi->hashcode;
+}
+
+/* Equality function for two shared_bitmap_info_t's. */
+
+static int
+shared_bitmap_eq (const void *p1, const void *p2)
+{
+ const shared_bitmap_info_t sbi1 = (shared_bitmap_info_t) p1;
+ const shared_bitmap_info_t sbi2 = (shared_bitmap_info_t) p2;
+ return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
+}
+
+/* Lookup a bitmap in the shared bitmap hashtable, and return an already
+ existing instance if there is one, NULL otherwise. */
+
+static bitmap
+shared_bitmap_lookup (bitmap pt_vars)
+{
+ void **slot;
+ struct shared_bitmap_info sbi;
+
+ sbi.pt_vars = pt_vars;
+ sbi.hashcode = bitmap_hash (pt_vars);
+
+ slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
+ sbi.hashcode, NO_INSERT);
+ if (!slot)
+ return NULL;
+ else
+ return ((shared_bitmap_info_t) *slot)->pt_vars;
+}
+
+
+/* Add a bitmap to the shared bitmap hashtable. */
+
+static void
+shared_bitmap_add (bitmap pt_vars)
+{
+ void **slot;
+ shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
+
+ sbi->pt_vars = pt_vars;
+ sbi->hashcode = bitmap_hash (pt_vars);
+
+ slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
+ sbi->hashcode, INSERT);
+ gcc_assert (!*slot);
+ *slot = (void *) sbi;
+}
+
+
/* 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. */
+ based alias analysis to prune the points-to sets.
+ IS_DEREFED is true if PTR was directly dereferenced, which we use to
+ help determine whether we are we are allowed to prune using TBAA.
+ If NO_TBAA_PRUNING is true, we do not perform any TBAA pruning of
+ the from set. */
static void
-set_uids_in_ptset (tree ptr, bitmap into, bitmap from)
+set_uids_in_ptset (tree ptr, bitmap into, bitmap from, bool is_derefed,
+ bool no_tbaa_pruning)
{
unsigned int i;
bitmap_iterator bi;
bitmap_set_bit (into, DECL_UID (sv->var));
}
else if (TREE_CODE (vi->decl) == VAR_DECL
- || TREE_CODE (vi->decl) == PARM_DECL)
+ || TREE_CODE (vi->decl) == PARM_DECL
+ || TREE_CODE (vi->decl) == RESULT_DECL)
{
if (var_can_have_subvars (vi->decl)
&& get_subvars_for_var (vi->decl))
if (sft)
{
var_alias_set = get_alias_set (sft);
- if (!vi->directly_dereferenced
+ if (no_tbaa_pruning
+ || (!is_derefed && !vi->directly_dereferenced)
|| alias_sets_conflict_p (ptr_alias_set, var_alias_set))
bitmap_set_bit (into, DECL_UID (sft));
}
else
{
var_alias_set = get_alias_set (vi->decl);
- if (!vi->directly_dereferenced
+ if (no_tbaa_pruning
+ || (!is_derefed && !vi->directly_dereferenced)
|| alias_sets_conflict_p (ptr_alias_set, var_alias_set))
bitmap_set_bit (into, DECL_UID (vi->decl));
}
calculation being a bit co-dependent, we can't just calculate SMT
used info whenever we want, we have to calculate it around the time
that find_what_p_points_to is called. */
-static bool used_smt_calculated;
/* Mark which SMT's are in use by points-to anything variables. */
-static void
+void
set_used_smts (void)
{
int i;
varinfo_t vi;
- used_smts = BITMAP_ALLOC (&ptabitmap_obstack);
+ used_smts = BITMAP_ALLOC (&pta_obstack);
for (i = 0; VEC_iterate (varinfo_t, varmap, i, vi); i++)
{
tree var = vi->decl;
tree smt;
- bitmap_iterator bi;
- unsigned int j;
var_ann_t va;
struct ptr_info_def *pi = NULL;
- if (TREE_CODE (vi->decl) == SSA_NAME)
+ /* For parm decls, the pointer info may be under the default
+ def. */
+ if (TREE_CODE (vi->decl) == PARM_DECL
+ && gimple_default_def (cfun, var))
+ pi = SSA_NAME_PTR_INFO (gimple_default_def (cfun, var));
+ else if (TREE_CODE (var) == SSA_NAME)
pi = SSA_NAME_PTR_INFO (var);
/* Skip the special variables and those without their own
solution set. */
- if (vi->is_special_var || vi->node != vi->id || !SSA_VAR_P (var)
- || (pi && !pi->is_dereferenced)
- || (DECL_P (var) && !may_be_aliased (var)))
+ if (vi->is_special_var || find (vi->id) != vi->id
+ || !SSA_VAR_P (var)
+ || (pi && !pi->is_dereferenced)
+ || (TREE_CODE (var) == VAR_DECL && !may_be_aliased (var))
+ || !POINTER_TYPE_P (TREE_TYPE (var)))
continue;
if (TREE_CODE (var) == SSA_NAME)
continue;
smt = va->symbol_mem_tag;
- if (smt)
- {
- EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, j, bi)
- {
- if (get_varinfo (j)->is_artificial_var)
- {
- bitmap_set_bit (used_smts, DECL_UID (smt));
- break;
- }
- }
- }
+ if (smt && bitmap_bit_p (vi->solution, anything_id))
+ bitmap_set_bit (used_smts, DECL_UID (smt));
}
- used_smt_calculated = true;
}
-/* Merge the necessary SMT's into the solution set for VI, which is
+/* Merge the necessary SMT's into the bitmap INTO, which is
P's varinfo. This involves merging all SMT's that are a subset of
the SMT necessary for P. */
static void
-merge_smts_into (tree p, varinfo_t vi)
+merge_smts_into (tree p, bitmap solution)
{
unsigned int i;
bitmap_iterator bi;
tree smt;
- VEC(tree, gc) *aliases;
+ bitmap aliases;
tree var = p;
if (TREE_CODE (p) == SSA_NAME)
/* Need to set the SMT subsets first before this
will work properly. */
- bitmap_set_bit (vi->finished_solution, DECL_UID (smt));
+ bitmap_set_bit (solution, DECL_UID (smt));
EXECUTE_IF_SET_IN_BITMAP (used_smts, 0, i, bi)
{
tree newsmt = referenced_var (i);
if (alias_set_subset_of (get_alias_set (newsmttype),
smtset))
- bitmap_set_bit (vi->finished_solution, i);
+ bitmap_set_bit (solution, i);
}
- aliases = var_ann (smt)->may_aliases;
+ aliases = MTAG_ALIASES (smt);
if (aliases)
- {
- size_t k;
- tree al;
- for (k = 0; VEC_iterate (tree, aliases, k, al); k++)
- bitmap_set_bit (vi->finished_solution,
- DECL_UID (al));
- }
+ bitmap_ior_into (solution, aliases);
}
}
/* Given a pointer variable P, fill in its points-to set, or return
- false if we can't.
+ false if we can't.
Rather than return false for variables that point-to anything, we
instead find the corresponding SMT, and merge in it's aliases. In
addition to these aliases, we also set the bits for the SMT's
bool
find_what_p_points_to (tree p)
{
- unsigned int id = 0;
tree lookup_p = p;
+ varinfo_t vi;
if (!have_alias_info)
return false;
decl. */
if (TREE_CODE (p) == SSA_NAME
&& TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
- && gimple_default_def (cfun, SSA_NAME_VAR (p)) == p)
+ && SSA_NAME_IS_DEFAULT_DEF (p))
lookup_p = SSA_NAME_VAR (p);
- if (lookup_id_for_tree (lookup_p, &id))
+ vi = lookup_vi_for_tree (lookup_p);
+ if (vi)
{
- varinfo_t vi = get_varinfo (id);
-
if (vi->is_artificial_var)
return false;
unsigned int i;
bitmap_iterator bi;
bool was_pt_anything = false;
-
+ bitmap finished_solution;
+ bitmap result;
+
if (!pi->is_dereferenced)
return false;
/* This variable may have been collapsed, let's get the real
variable. */
- vi = get_varinfo (vi->node);
+ vi = get_varinfo (find (vi->id));
/* Translate artificial variables into SSA_NAME_PTR_INFO
attributes. */
}
}
- /* Share the final set of variables between the SSA_NAME
- pointer infos for collapsed nodes that are collapsed to
- non-special variables. This is because special vars have
- no real types associated with them, so while we know the
- pointers are equivalent to them, we need to generate the
- solution separately since it will include SMT's from the
- original non-collapsed variable. */
- if (!vi->is_special_var && vi->finished_solution)
+ /* Share the final set of variables when possible. */
+
+ finished_solution = BITMAP_GGC_ALLOC ();
+ stats.points_to_sets_created++;
+
+ /* Instead of using pt_anything, we merge in the SMT aliases
+ for the underlying SMT. In addition, if they could have
+ pointed to anything, they could point to global memory.
+ But we cannot do that for ref-all pointers because these
+ aliases have not been computed yet. */
+ if (was_pt_anything)
+ {
+ if (PTR_IS_REF_ALL (p))
+ {
+ pi->pt_anything = 1;
+ return false;
+ }
+
+ merge_smts_into (p, finished_solution);
+ pi->pt_global_mem = 1;
+ }
+
+ set_uids_in_ptset (vi->decl, finished_solution, vi->solution,
+ vi->directly_dereferenced,
+ vi->no_tbaa_pruning);
+ result = shared_bitmap_lookup (finished_solution);
+
+ if (!result)
{
- pi->pt_vars = vi->finished_solution;
+ shared_bitmap_add (finished_solution);
+ pi->pt_vars = finished_solution;
}
else
{
- vi->finished_solution = BITMAP_GGC_ALLOC ();
-
- /* Instead of using pt_anything, we instead merge in the SMT
- aliases for the underlying SMT. */
- if (was_pt_anything)
- {
- if (!used_smt_calculated)
- set_used_smts ();
- merge_smts_into (p, vi);
- pi->pt_global_mem = 1;
-
- }
- set_uids_in_ptset (vi->decl, vi->finished_solution, vi->solution);
- pi->pt_vars = vi->finished_solution;
+ pi->pt_vars = result;
+ bitmap_clear (finished_solution);
}
if (bitmap_empty_p (pi->pt_vars))
{
fprintf (outfile, "Stats:\n");
fprintf (outfile, "Total vars: %d\n", stats.total_vars);
+ fprintf (outfile, "Non-pointer vars: %d\n",
+ stats.nonpointer_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);
+ fprintf (outfile, "Number of implicit edges: %d\n",
+ stats.num_implicit_edges);
}
for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
/* 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 = new_var_info (nothing_tree, 0, "NULL");
+ insert_vi_for_tree (nothing_tree, var_nothing);
var_nothing->is_artificial_var = 1;
var_nothing->offset = 0;
var_nothing->size = ~0;
/* 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 = new_var_info (anything_tree, 1, "ANYTHING");
+ insert_vi_for_tree (anything_tree, var_anything);
var_anything->is_artificial_var = 1;
var_anything->size = ~0;
var_anything->offset = 0;
lhs.type = SCALAR;
lhs.var = anything_id;
lhs.offset = 0;
- rhs.type = INCLUDES;
+ 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
/* 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 = new_var_info (readonly_tree, 2, "READONLY");
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);
+ insert_vi_for_tree (readonly_tree, var_readonly);
readonly_id = 2;
VEC_safe_push (varinfo_t, heap, varmap, var_readonly);
lhs.type = SCALAR;
lhs.var = readonly_id;
lhs.offset = 0;
- rhs.type = INCLUDES;
+ rhs.type = ADDRESSOF;
rhs.var = anything_id;
rhs.offset = 0;
/* 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 = new_var_info (integer_tree, 3, "INTEGER");
+ insert_vi_for_tree (integer_tree, var_integer);
var_integer->is_artificial_var = 1;
var_integer->size = ~0;
var_integer->fullsize = ~0;
lhs.type = SCALAR;
lhs.var = integer_id;
lhs.offset = 0;
- rhs.type = INCLUDES;
+ rhs.type = ADDRESSOF;
rhs.var = anything_id;
rhs.offset = 0;
process_constraint (new_constraint (lhs, rhs));
static void
init_alias_vars (void)
{
- bitmap_obstack_initialize (&ptabitmap_obstack);
+ bitmap_obstack_initialize (&pta_obstack);
+ bitmap_obstack_initialize (&oldpta_obstack);
bitmap_obstack_initialize (&predbitmap_obstack);
constraint_pool = create_alloc_pool ("Constraint pool",
sizeof (struct variable_info), 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));
+ vi_for_tree = pointer_map_create ();
+ memset (&stats, 0, sizeof (stats));
+ shared_bitmap_table = htab_create (511, shared_bitmap_hash,
+ shared_bitmap_eq, free);
init_base_vars ();
}
+/* Remove the REF and ADDRESS edges from GRAPH, as well as all the
+ predecessor edges. */
+
+static void
+remove_preds_and_fake_succs (constraint_graph_t graph)
+{
+ unsigned int i;
+
+ /* Clear the implicit ref and address nodes from the successor
+ lists. */
+ for (i = 0; i < FIRST_REF_NODE; i++)
+ {
+ if (graph->succs[i])
+ bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
+ FIRST_REF_NODE * 2);
+ }
+
+ /* Free the successor list for the non-ref nodes. */
+ for (i = FIRST_REF_NODE; i < graph->size; i++)
+ {
+ if (graph->succs[i])
+ BITMAP_FREE (graph->succs[i]);
+ }
+
+ /* Now reallocate the size of the successor list as, and blow away
+ the predecessor bitmaps. */
+ graph->size = VEC_length (varinfo_t, varmap);
+ graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
+
+ free (graph->implicit_preds);
+ graph->implicit_preds = NULL;
+ free (graph->preds);
+ graph->preds = NULL;
+ bitmap_obstack_release (&predbitmap_obstack);
+}
+
+/* Compute the set of variables we can't TBAA prune. */
+
+static void
+compute_tbaa_pruning (void)
+{
+ unsigned int size = VEC_length (varinfo_t, varmap);
+ unsigned int i;
+ bool any;
+
+ changed_count = 0;
+ changed = sbitmap_alloc (size);
+ sbitmap_zero (changed);
+
+ /* Mark all initial no_tbaa_pruning nodes as changed. */
+ any = false;
+ for (i = 0; i < size; ++i)
+ {
+ varinfo_t ivi = get_varinfo (i);
+
+ if (find (i) == i && ivi->no_tbaa_pruning)
+ {
+ any = true;
+ if ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
+ || VEC_length (constraint_t, graph->complex[i]) > 0)
+ {
+ SET_BIT (changed, i);
+ ++changed_count;
+ }
+ }
+ }
+
+ while (changed_count > 0)
+ {
+ struct topo_info *ti = init_topo_info ();
+ ++stats.iterations;
+
+ bitmap_obstack_initialize (&iteration_obstack);
+
+ compute_topo_order (graph, ti);
+
+ while (VEC_length (unsigned, ti->topo_order) != 0)
+ {
+ bitmap_iterator bi;
+
+ i = VEC_pop (unsigned, ti->topo_order);
+
+ /* If this variable is not a representative, skip it. */
+ if (find (i) != i)
+ continue;
+
+ /* 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;
+ VEC(constraint_t,heap) *complex = graph->complex[i];
+
+ RESET_BIT (changed, i);
+ --changed_count;
+
+ /* Process the complex copy constraints. */
+ for (j = 0; VEC_iterate (constraint_t, complex, j, c); ++j)
+ {
+ if (c->lhs.type == SCALAR && c->rhs.type == SCALAR)
+ {
+ varinfo_t lhsvi = get_varinfo (find (c->lhs.var));
+
+ if (!lhsvi->no_tbaa_pruning)
+ {
+ lhsvi->no_tbaa_pruning = true;
+ if (!TEST_BIT (changed, lhsvi->id))
+ {
+ SET_BIT (changed, lhsvi->id);
+ ++changed_count;
+ }
+ }
+ }
+ }
+
+ /* Propagate to all successors. */
+ EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 0, j, bi)
+ {
+ unsigned int to = find (j);
+ varinfo_t tovi = get_varinfo (to);
+
+ /* Don't propagate to ourselves. */
+ if (to == i)
+ continue;
+
+ if (!tovi->no_tbaa_pruning)
+ {
+ tovi->no_tbaa_pruning = true;
+ if (!TEST_BIT (changed, to))
+ {
+ SET_BIT (changed, to);
+ ++changed_count;
+ }
+ }
+ }
+ }
+ }
+
+ free_topo_info (ti);
+ bitmap_obstack_release (&iteration_obstack);
+ }
+
+ sbitmap_free (changed);
+
+ if (any)
+ {
+ for (i = 0; i < size; ++i)
+ {
+ varinfo_t ivi = get_varinfo (i);
+ varinfo_t ivip = get_varinfo (find (i));
+
+ if (ivip->no_tbaa_pruning)
+ {
+ tree var = ivi->decl;
+
+ if (TREE_CODE (var) == SSA_NAME)
+ var = SSA_NAME_VAR (var);
+
+ if (POINTER_TYPE_P (TREE_TYPE (var)))
+ {
+ DECL_NO_TBAA_P (var) = 1;
+
+ /* Tell the RTL layer that this pointer can alias
+ anything. */
+ DECL_POINTER_ALIAS_SET (var) = 0;
+ }
+ }
+ }
+ }
+}
+
/* 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)
{
+ struct scc_info *si;
basic_block bb;
timevar_push (TV_TREE_PTA);
init_alias_vars ();
+ init_alias_heapvars ();
intra_create_variable_infos ();
block_stmt_iterator bsi;
tree phi;
- for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
+ for (phi = phi_nodes (bb); phi; phi = PHI_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
}
}
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
tree stmt = bsi_stmt (bsi);
find_func_aliases (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);
+
+ /* The information in CHANGE_DYNAMIC_TYPE_EXPR nodes has now
+ been captured, and we can remove them. */
+ if (TREE_CODE (stmt) == CHANGE_DYNAMIC_TYPE_EXPR)
+ bsi_remove (&bsi, true);
+ else
+ bsi_next (&bsi);
}
}
- build_constraint_graph ();
if (dump_file)
{
fprintf (dump_file,
"\nCollapsing static cycles and doing variable "
"substitution:\n");
+ build_pred_graph ();
+ si = perform_var_substitution (graph);
+ move_complex_constraints (graph, si);
+ free_var_substitution_info (si);
- find_and_collapse_graph_cycles (graph, false);
- perform_var_substitution (graph);
+ build_succ_graph ();
+ find_indirect_cycles (graph);
+
+ /* Implicit nodes and predecessors are no longer necessary at this
+ point. */
+ remove_preds_and_fake_succs (graph);
if (dump_file)
fprintf (dump_file, "\nSolving graph:\n");
solve_graph (graph);
- used_smt_calculated = false;
+ compute_tbaa_pruning ();
if (dump_file)
dump_sa_points_to_info (dump_file);
varinfo_t v;
int i;
- htab_delete (id_for_tree);
- bitmap_obstack_release (&ptabitmap_obstack);
- bitmap_obstack_release (&predbitmap_obstack);
+ htab_delete (shared_bitmap_table);
+ if (dump_file && (dump_flags & TDF_STATS))
+ fprintf (dump_file, "Points to sets created:%d\n",
+ stats.points_to_sets_created);
+
+ pointer_map_destroy (vi_for_tree);
+ bitmap_obstack_release (&pta_obstack);
VEC_free (constraint_t, heap, constraints);
for (i = 0; VEC_iterate (varinfo_t, varmap, i, v); i++)
- VEC_free (constraint_t, heap, v->complex);
+ VEC_free (constraint_t, heap, graph->complex[i]);
+ free (graph->complex);
- free (graph->preds);
+ free (graph->rep);
free (graph->succs);
+ free (graph->indirect_cycles);
free (graph);
VEC_free (varinfo_t, heap, varmap);
ipa_pta_execute (void)
{
struct cgraph_node *node;
+ struct scc_info *si;
+
in_ipa_mode = 1;
init_alias_heapvars ();
init_alias_vars ();
block_stmt_iterator bsi;
tree phi;
- for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
{
if (is_gimple_reg (PHI_RESULT (phi)))
{
}
}
- build_constraint_graph ();
+
if (dump_file)
{
"\nCollapsing static cycles and doing variable "
"substitution:\n");
- find_and_collapse_graph_cycles (graph, false);
- perform_var_substitution (graph);
+ build_pred_graph ();
+ si = perform_var_substitution (graph);
+ move_complex_constraints (graph, si);
+ free_var_substitution_info (si);
+
+ build_succ_graph ();
+ find_indirect_cycles (graph);
+
+ /* Implicit nodes and predecessors are no longer necessary at this
+ point. */
+ remove_preds_and_fake_succs (graph);
if (dump_file)
fprintf (dump_file, "\nSolving graph:\n");
solve_graph (graph);
- set_used_smts ();
if (dump_file)
dump_sa_points_to_info (dump_file);
void
init_alias_heapvars (void)
{
- heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, tree_map_eq,
- NULL);
+ if (!heapvar_for_stmt)
+ heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, tree_map_eq,
+ NULL);
}
void
delete_alias_heapvars (void)
{
htab_delete (heapvar_for_stmt);
+ heapvar_for_stmt = NULL;
}
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