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tree-ssa-structalias.h (compute_points_to_sets): Adjust prototype.

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2008-06-29  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-structalias.h (compute_points_to_sets): Adjust
	prototype.
	(struct alias_info): Move ...
	* tree-ssa-alias.c: ... here.
	(update_alias_info): Declare.
	(compute_may_aliases): Call it.
	(update_alias_info): New function.
	* tree-ssa-structalias.c (update_alias_info): Move ...
	* tree-ssa-alias.c (update_alias_info_1): ... here.
	* tree-ssa-structalias.c (process_constraint_1): Remove
	unused from_call argument.  Rename to ...
	(process_constraint): ... this.  Delete old wrapper.
	(make_constraint_to): Adjust callers.
	(handle_const_call): Likewise.
	(handle_pure_call): Likewise.
	(init_base_vars): Likewise.
	(handle_lhs_call): Likewise.  Remove unnecessary constraint.
	(find_func_aliases): We don't need structure copies for
	complex types.
	(make_constraint_from_anything): Remove.
	(create_variable_info_for): For globals make constraints
	from escaped, not from anything.
	(compute_points_to_sets): Do not call update_alias_info.
	(ipa_pta_execute): Use make_constraint_from.

From-SVN: r137252
This commit is contained in:
Richard Guenther 2008-06-29 15:44:00 +00:00 • committed by Richard Biener
parent b03717765d
commit faf2ecc57e
4 changed files with 364 additions and 347 deletions
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27
gcc/ChangeLog
View file

@ -1,3 +1,30 @@
2008-06-29 Richard Guenther <rguenther@suse.de>
* tree-ssa-structalias.h (compute_points_to_sets): Adjust
prototype.
(struct alias_info): Move ...
* tree-ssa-alias.c: ... here.
(update_alias_info): Declare.
(compute_may_aliases): Call it.
(update_alias_info): New function.
* tree-ssa-structalias.c (update_alias_info): Move ...
* tree-ssa-alias.c (update_alias_info_1): ... here.
* tree-ssa-structalias.c (process_constraint_1): Remove
unused from_call argument. Rename to ...
(process_constraint): ... this. Delete old wrapper.
(make_constraint_to): Adjust callers.
(handle_const_call): Likewise.
(handle_pure_call): Likewise.
(init_base_vars): Likewise.
(handle_lhs_call): Likewise. Remove unnecessary constraint.
(find_func_aliases): We don't need structure copies for
complex types.
(make_constraint_from_anything): Remove.
(create_variable_info_for): For globals make constraints
from escaped, not from anything.
(compute_points_to_sets): Do not call update_alias_info.
(ipa_pta_execute): Use make_constraint_from.
2008-06-29 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* Makefile.in (CXX_COMPAT_WARN, cxx_compat_warn): Delete.

306
gcc/tree-ssa-alias.c
View file

@ -166,6 +166,40 @@ along with GCC; see the file COPYING3. If not see
Lastly, we delete partitions with no symbols, and clean up after
ourselves. */
/* Alias information used by compute_may_aliases and its helpers. */
struct alias_info
{
/* SSA names visited while collecting points-to information. If bit I
is set, it means that SSA variable with version I has already been
visited. */
sbitmap ssa_names_visited;
/* Array of SSA_NAME pointers processed by the points-to collector. */
VEC(tree,heap) *processed_ptrs;
/* ADDRESSABLE_VARS contains all the global variables and locals that
have had their address taken. */
struct alias_map_d **addressable_vars;
size_t num_addressable_vars;
/* POINTERS contains all the _DECL pointers with unique memory tags
that have been referenced in the program. */
struct alias_map_d **pointers;
size_t num_pointers;
/* Variables that have been written to directly (i.e., not through a
pointer dereference). */
struct pointer_set_t *written_vars;
/* Pointers that have been used in an indirect store operation. */
struct pointer_set_t *dereferenced_ptrs_store;
/* Pointers that have been used in an indirect load operation. */
struct pointer_set_t *dereferenced_ptrs_load;
};
/* Structure to map a variable to its alias set. */
struct alias_map_d
{
@ -205,6 +239,7 @@ static struct alias_info *init_alias_info (void);
static void delete_alias_info (struct alias_info *);
static void compute_flow_sensitive_aliasing (struct alias_info *);
static void setup_pointers_and_addressables (struct alias_info *);
static void update_alias_info (struct alias_info *);
static void create_global_var (void);
static void maybe_create_global_var (void);
static void set_pt_anything (tree);
@ -1722,7 +1757,12 @@ compute_may_aliases (void)
address of V escapes the current function, making V call-clobbered
(i.e., whether &V is stored in a global variable or if its passed as a
function call argument). */
compute_points_to_sets (ai);
compute_points_to_sets ();
/* 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 (ai);
/* Collect all pointers and addressable variables, compute alias sets,
create memory tags for pointers and promote variables whose address is
@ -2438,6 +2478,270 @@ create_alias_map_for (tree var, struct alias_info *ai)
}
/* Update related alias information kept in AI. This is used when
building name tags, alias sets and deciding grouping heuristics.
STMT is the statement to process. This function also updates
ADDRESSABLE_VARS. */
static void
update_alias_info_1 (tree stmt, struct alias_info *ai)
{
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);
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)
{
mem_ref_stats->num_call_sites++;
if (stmt_escape_type == ESCAPE_TO_PURE_CONST)
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);
if (addr_taken)
bitmap_ior_into (gimple_addressable_vars (cfun), addr_taken);
/* 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;
unsigned num_uses, num_loads, num_stores;
op = USE_FROM_PTR (use_p);
/* If STMT is a PHI node, OP may be an ADDR_EXPR. If so, add it
to the set of addressable variables. */
if (TREE_CODE (op) == ADDR_EXPR)
{
bitmap addressable_vars = gimple_addressable_vars (cfun);
gcc_assert (TREE_CODE (stmt) == PHI_NODE);
gcc_assert (addressable_vars);
/* PHI nodes don't have annotations for pinning the set
of addresses taken, so we collect them here.
FIXME, should we allow PHI nodes to have annotations
so that they can be treated like regular statements?
Currently, they are treated as second-class
statements. */
add_to_addressable_set (TREE_OPERAND (op, 0), &addressable_vars);
continue;
}
/* Ignore constants (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
it cannot be aliased. */
gcc_assert (!may_be_aliased (var));
/* We are only interested in pointers. */
if (!POINTER_TYPE_P (TREE_TYPE (op)))
continue;
pi = get_ptr_info (op);
/* Add OP to AI->PROCESSED_PTRS, if it's not there already. */
if (!TEST_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op)))
{
SET_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op));
VEC_safe_push (tree, heap, ai->processed_ptrs, op);
}
/* If STMT is a PHI node, then it will not have pointer
dereferences and it will not be an escape point. */
if (TREE_CODE (stmt) == PHI_NODE)
continue;
/* Determine whether OP is a dereferenced pointer, and if STMT
is an escape point, whether OP escapes. */
count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
/* For directly dereferenced pointers we can apply
TBAA-pruning to their points-to set. We may not count the
implicit dereferences &PTR->FLD here. */
if (num_loads + num_stores > 0)
pi->is_dereferenced = 1;
/* Handle a corner case involving address expressions of the
form '&PTR->FLD'. The problem with these expressions is that
they do not represent a dereference of PTR. However, if some
other transformation propagates them into an INDIRECT_REF
expression, we end up with '*(&PTR->FLD)' which is folded
into 'PTR->FLD'.
So, if the original code had no other dereferences of PTR,
the aliaser will not create memory tags for it, and when
&PTR->FLD gets propagated to INDIRECT_REF expressions, the
memory operations will receive no 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
is not really a dereference but an offset calculation.
What we do here is to recognize these special ADDR_EXPR
nodes. Since these expressions are never GIMPLE values (they
are not GIMPLE invariants), they can only appear on the RHS
of an assignment and their base address is always an
INDIRECT_REF expression. */
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 = 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)
num_loads++;
}
if (num_loads + num_stores > 0)
{
/* Mark OP as dereferenced. In a subsequent pass,
dereferenced pointers that point to a set of
variables will be assigned a name tag to alias
all the variables OP points to. */
pi->memory_tag_needed = 1;
/* ??? For always executed direct dereferences we can
apply TBAA-pruning to their escape set. */
/* If this is a store operation, mark OP as being
dereferenced to store, otherwise mark it as being
dereferenced to load. */
if (num_stores > 0)
pointer_set_insert (ai->dereferenced_ptrs_store, var);
else
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_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
escapes and so the pointed-to variables need to
be marked call-clobbered. */
pi->value_escapes_p = 1;
pi->escape_mask |= stmt_escape_type;
/* If the statement makes a function call, assume
that pointer OP will be dereferenced in a store
operation inside the called function. */
if (get_call_expr_in (stmt)
|| stmt_escape_type == ESCAPE_STORED_IN_GLOBAL)
{
pointer_set_insert (ai->dereferenced_ptrs_store, var);
pi->memory_tag_needed = 1;
}
}
}
if (TREE_CODE (stmt) == PHI_NODE)
return;
/* 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))
{
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);
}
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);
}
}
/* Update various related attributes like escaped addresses,
pointer dereferences for loads and stores. This is used
when creating name tags and alias sets. */
static void
update_alias_info (struct alias_info *ai)
{
basic_block bb;
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
if (is_gimple_reg (PHI_RESULT (phi)))
update_alias_info_1 (phi, ai);
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
update_alias_info_1 (bsi_stmt (bsi), ai);
}
}
/* Create memory tags for all the dereferenced pointers and build the
ADDRESSABLE_VARS and POINTERS arrays used for building the may-alias
sets. Based on the address escape and points-to information collected

344
gcc/tree-ssa-structalias.c
View file

@ -2526,13 +2526,11 @@ get_constraint_exp_from_ssa_var (tree t)
return cexpr;
}
/* Process a completed constraint T, and add it to the constraint
list. FROM_CALL is true if this is a constraint coming from a
call, which means any DEREFs we see are "may-deref's", not
"must-deref"'s. */
/* Process constraint T, performing various simplifications and then
adding it to our list of overall constraints. */
static void
process_constraint_1 (constraint_t t, bool from_call)
process_constraint (constraint_t t)
{
struct constraint_expr rhs = t->rhs;
struct constraint_expr lhs = t->lhs;
@ -2556,7 +2554,7 @@ process_constraint_1 (constraint_t t, bool from_call)
rhs = t->lhs;
t->lhs = t->rhs;
t->rhs = rhs;
process_constraint_1 (t, from_call);
process_constraint (t);
}
/* This can happen in our IR with things like n->a = *p */
else if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
@ -2574,8 +2572,8 @@ process_constraint_1 (constraint_t t, bool from_call)
gcc_assert (!AGGREGATE_TYPE_P (pointedtotype)
|| get_varinfo (rhs.var)->is_unknown_size_var);
process_constraint_1 (new_constraint (tmplhs, rhs), from_call);
process_constraint_1 (new_constraint (lhs, tmplhs), from_call);
process_constraint (new_constraint (tmplhs, rhs));
process_constraint (new_constraint (lhs, tmplhs));
}
else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
{
@ -2585,8 +2583,8 @@ process_constraint_1 (constraint_t t, bool from_call)
tree tmpvar = create_tmp_var_raw (pointertype, "derefaddrtmp");
struct constraint_expr tmplhs = get_constraint_exp_from_ssa_var (tmpvar);
process_constraint_1 (new_constraint (tmplhs, rhs), from_call);
process_constraint_1 (new_constraint (lhs, tmplhs), from_call);
process_constraint (new_constraint (tmplhs, rhs));
process_constraint (new_constraint (lhs, tmplhs));
}
else
{
@ -2595,16 +2593,6 @@ process_constraint_1 (constraint_t t, bool from_call)
}
}
/* Process constraint T, performing various simplifications and then
adding it to our list of overall constraints. */
static void
process_constraint (constraint_t t)
{
process_constraint_1 (t, false);
}
/* Return true if T is a variable of a type that could contain
pointers. */
@ -3267,248 +3255,6 @@ do_structure_copy (tree lhsop, tree rhsop)
}
/* Update related alias information kept in AI. This is used when
building name tags, alias sets and deciding grouping heuristics.
STMT is the statement to process. This function also updates
ADDRESSABLE_VARS. */
static void
update_alias_info (tree stmt, struct alias_info *ai)
{
bitmap addr_taken;
use_operand_p use_p;
ssa_op_iter iter;
bool stmt_dereferences_ptr_p;
enum escape_type stmt_escape_type = is_escape_site (stmt);
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)
{
mem_ref_stats->num_call_sites++;
if (stmt_escape_type == ESCAPE_TO_PURE_CONST)
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);
if (addr_taken)
bitmap_ior_into (gimple_addressable_vars (cfun), addr_taken);
/* 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;
unsigned num_uses, num_loads, num_stores;
op = USE_FROM_PTR (use_p);
/* If STMT is a PHI node, OP may be an ADDR_EXPR. If so, add it
to the set of addressable variables. */
if (TREE_CODE (op) == ADDR_EXPR)
{
bitmap addressable_vars = gimple_addressable_vars (cfun);
gcc_assert (TREE_CODE (stmt) == PHI_NODE);
gcc_assert (addressable_vars);
/* PHI nodes don't have annotations for pinning the set
of addresses taken, so we collect them here.
FIXME, should we allow PHI nodes to have annotations
so that they can be treated like regular statements?
Currently, they are treated as second-class
statements. */
add_to_addressable_set (TREE_OPERAND (op, 0), &addressable_vars);
continue;
}
/* Ignore constants (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
it cannot be aliased. */
gcc_assert (!may_be_aliased (var));
/* We are only interested in pointers. */
if (!POINTER_TYPE_P (TREE_TYPE (op)))
continue;
pi = get_ptr_info (op);
/* Add OP to AI->PROCESSED_PTRS, if it's not there already. */
if (!TEST_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op)))
{
SET_BIT (ai->ssa_names_visited, SSA_NAME_VERSION (op));
VEC_safe_push (tree, heap, ai->processed_ptrs, op);
}
/* If STMT is a PHI node, then it will not have pointer
dereferences and it will not be an escape point. */
if (TREE_CODE (stmt) == PHI_NODE)
continue;
/* Determine whether OP is a dereferenced pointer, and if STMT
is an escape point, whether OP escapes. */
count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
/* For directly dereferenced pointers we can apply
TBAA-pruning to their points-to set. We may not count the
implicit dereferences &PTR->FLD here. */
if (num_loads + num_stores > 0)
pi->is_dereferenced = 1;
/* Handle a corner case involving address expressions of the
form '&PTR->FLD'. The problem with these expressions is that
they do not represent a dereference of PTR. However, if some
other transformation propagates them into an INDIRECT_REF
expression, we end up with '*(&PTR->FLD)' which is folded
into 'PTR->FLD'.
So, if the original code had no other dereferences of PTR,
the aliaser will not create memory tags for it, and when
&PTR->FLD gets propagated to INDIRECT_REF expressions, the
memory operations will receive no 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
is not really a dereference but an offset calculation.
What we do here is to recognize these special ADDR_EXPR
nodes. Since these expressions are never GIMPLE values (they
are not GIMPLE invariants), they can only appear on the RHS
of an assignment and their base address is always an
INDIRECT_REF expression. */
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 = 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)
num_loads++;
}
if (num_loads + num_stores > 0)
{
/* Mark OP as dereferenced. In a subsequent pass,
dereferenced pointers that point to a set of
variables will be assigned a name tag to alias
all the variables OP points to. */
pi->memory_tag_needed = 1;
/* ??? For always executed direct dereferences we can
apply TBAA-pruning to their escape set. */
/* If this is a store operation, mark OP as being
dereferenced to store, otherwise mark it as being
dereferenced to load. */
if (num_stores > 0)
pointer_set_insert (ai->dereferenced_ptrs_store, var);
else
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_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
escapes and so the pointed-to variables need to
be marked call-clobbered. */
pi->value_escapes_p = 1;
pi->escape_mask |= stmt_escape_type;
/* If the statement makes a function call, assume
that pointer OP will be dereferenced in a store
operation inside the called function. */
if (get_call_expr_in (stmt)
|| stmt_escape_type == ESCAPE_STORED_IN_GLOBAL)
{
pointer_set_insert (ai->dereferenced_ptrs_store, var);
pi->memory_tag_needed = 1;
}
}
}
if (TREE_CODE (stmt) == PHI_NODE)
return;
/* 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))
{
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);
}
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);
}
}
/* Handle pointer arithmetic EXPR when creating aliasing constraints.
Expressions of the type PTR + CST can be handled in two ways:
@ -3598,7 +3344,7 @@ make_constraint_to (unsigned id, tree op)
get_constraint_for (op, &rhsc);
for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++)
process_constraint_1 (new_constraint (includes, *c), true);
process_constraint (new_constraint (includes, *c));
VEC_free (ce_s, heap, rhsc);
}
@ -3643,16 +3389,11 @@ handle_lhs_call (tree lhs)
struct constraint_expr *lhsp;
get_constraint_for (lhs, &lhsc);
rhsc.var = nonlocal_id;
rhsc.offset = 0;
rhsc.type = ADDRESSOF;
for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
process_constraint_1 (new_constraint (*lhsp, rhsc), true);
rhsc.var = escaped_id;
rhsc.offset = 0;
rhsc.type = ADDRESSOF;
for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
process_constraint_1 (new_constraint (*lhsp, rhsc), true);
process_constraint (new_constraint (*lhsp, rhsc));
VEC_free (ce_s, heap, lhsc);
}
@ -3680,7 +3421,7 @@ handle_const_call (tree stmt)
rhsc.offset = 0;
rhsc.type = ADDRESSOF;
for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
process_constraint_1 (new_constraint (*lhsp, rhsc), true);
process_constraint (new_constraint (*lhsp, rhsc));
VEC_free (ce_s, heap, lhsc);
return;
}
@ -3690,7 +3431,7 @@ handle_const_call (tree stmt)
rhsc.offset = 0;
rhsc.type = ADDRESSOF;
for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
process_constraint_1 (new_constraint (*lhsp, rhsc), true);
process_constraint (new_constraint (*lhsp, rhsc));
/* May return arguments. */
FOR_EACH_CALL_EXPR_ARG (arg, iter, call)
@ -3702,7 +3443,7 @@ handle_const_call (tree stmt)
get_constraint_for (arg, &argc);
for (i = 0; VEC_iterate (ce_s, argc, i, argp); i++)
for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
process_constraint_1 (new_constraint (*lhsp, *argp), true);
process_constraint (new_constraint (*lhsp, *argp));
VEC_free (ce_s, heap, argc);
}
@ -3748,7 +3489,7 @@ handle_pure_call (tree stmt)
rhsc.offset = 0;
rhsc.type = ADDRESSOF;
for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
process_constraint_1 (new_constraint (*lhsp, rhsc), true);
process_constraint (new_constraint (*lhsp, rhsc));
VEC_free (ce_s, heap, lhsc);
return;
}
@ -3759,7 +3500,7 @@ handle_pure_call (tree stmt)
rhsc.offset = 0;
rhsc.type = ADDRESSOF;
for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
process_constraint_1 (new_constraint (*lhsp, rhsc), true);
process_constraint (new_constraint (*lhsp, rhsc));
VEC_free (ce_s, heap, lhsc);
}
}
@ -3957,10 +3698,8 @@ find_func_aliases (tree origt)
tree rhsop = GIMPLE_STMT_OPERAND (t, 1);
int i;
if ((AGGREGATE_TYPE_P (TREE_TYPE (lhsop))
|| TREE_CODE (TREE_TYPE (lhsop)) == COMPLEX_TYPE)
&& (AGGREGATE_TYPE_P (TREE_TYPE (rhsop))
|| TREE_CODE (TREE_TYPE (lhsop)) == COMPLEX_TYPE))
if (AGGREGATE_TYPE_P (TREE_TYPE (lhsop))
&& AGGREGATE_TYPE_P (TREE_TYPE (rhsop)))
{
do_structure_copy (lhsop, rhsop);
}
@ -4340,13 +4079,6 @@ make_constraint_from (varinfo_t vi, int from)
process_constraint (new_constraint (lhs, rhs));
}
/* Create a constraint from ANYTHING variable to VI. */
static void
make_constraint_from_anything (varinfo_t vi)
{
make_constraint_from (vi, anything_id);
}
/* Count the number of arguments DECL has, and set IS_VARARGS to true
if it is a varargs function. */
@ -4552,8 +4284,9 @@ create_variable_info_for (tree decl, const char *name)
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);
if (is_global && (!flag_whole_program || !in_ipa_mode)
&& could_have_pointers (decl))
make_constraint_from (vi, escaped_id);
stats.total_vars++;
if (use_field_sensitive
@ -4633,8 +4366,9 @@ create_variable_info_for (tree decl, const char *name)
newvi->fullsize = vi->fullsize;
insert_into_field_list (vi, newvi);
VEC_safe_push (varinfo_t, heap, varmap, newvi);
if (is_global && (!flag_whole_program || !in_ipa_mode))
make_constraint_from_anything (newvi);
if (is_global && (!flag_whole_program || !in_ipa_mode)
&& (!fo->decl || could_have_pointers (fo->decl)))
make_constraint_from (newvi, escaped_id);
stats.total_vars++;
}
@ -5296,7 +5030,7 @@ init_base_vars (void)
rhs.type = DEREF;
rhs.var = escaped_id;
rhs.offset = 0;
process_constraint_1 (new_constraint (lhs, rhs), true);
process_constraint (new_constraint (lhs, rhs));
/* Create the NONLOCAL variable, used to represent the set of nonlocal
memory. */
@ -5339,7 +5073,7 @@ init_base_vars (void)
rhs.type = DEREF;
rhs.var = callused_id;
rhs.offset = 0;
process_constraint_1 (new_constraint (lhs, rhs), true);
process_constraint (new_constraint (lhs, rhs));
/* Create the INTEGER variable, used to represent that a variable points
to an INTEGER. */
@ -5372,7 +5106,7 @@ init_base_vars (void)
rhs.type = ADDRESSOF;
rhs.var = escaped_id;
rhs.offset = 0;
process_constraint_1 (new_constraint (lhs, rhs), true);
process_constraint (new_constraint (lhs, rhs));
/* *ESCAPED = &NONLOCAL. This is true because we have to assume
everything pointed to by escaped can also point to nonlocal. */
@ -5382,7 +5116,7 @@ init_base_vars (void)
rhs.type = ADDRESSOF;
rhs.var = nonlocal_id;
rhs.offset = 0;
process_constraint_1 (new_constraint (lhs, rhs), true);
process_constraint (new_constraint (lhs, rhs));
}
/* Initialize things necessary to perform PTA */
@ -5581,7 +5315,7 @@ compute_tbaa_pruning (void)
at the start of the file for an algorithmic overview. */
void
compute_points_to_sets (struct alias_info *ai)
compute_points_to_sets (void)
{
struct scc_info *si;
basic_block bb;
@ -5600,18 +5334,8 @@ compute_points_to_sets (struct alias_info *ai)
tree 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
sets. */
update_alias_info (phi, ai);
}
}
if (is_gimple_reg (PHI_RESULT (phi)))
find_func_aliases (phi);
for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
{
@ -5619,12 +5343,6 @@ compute_points_to_sets (struct alias_info *ai)
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)
@ -5761,7 +5479,7 @@ ipa_pta_execute (void)
{
varinfo_t fi = get_varinfo (varid);
for (; fi; fi = fi->next)
make_constraint_from_anything (fi);
make_constraint_from (fi, anything_id);
}
}
}

34
gcc/tree-ssa-structalias.h
View file

@ -24,44 +24,12 @@
struct constraint;
typedef struct constraint *constraint_t;
/* Alias information used by compute_may_aliases and its helpers. */
struct alias_info
{
/* SSA names visited while collecting points-to information. If bit I
is set, it means that SSA variable with version I has already been
visited. */
sbitmap ssa_names_visited;
/* Array of SSA_NAME pointers processed by the points-to collector. */
VEC(tree,heap) *processed_ptrs;
/* ADDRESSABLE_VARS contains all the global variables and locals that
have had their address taken. */
struct alias_map_d **addressable_vars;
size_t num_addressable_vars;
/* POINTERS contains all the _DECL pointers with unique memory tags
that have been referenced in the program. */
struct alias_map_d **pointers;
size_t num_pointers;
/* Variables that have been written to directly (i.e., not through a
pointer dereference). */
struct pointer_set_t *written_vars;
/* Pointers that have been used in an indirect store operation. */
struct pointer_set_t *dereferenced_ptrs_store;
/* Pointers that have been used in an indirect load operation. */
struct pointer_set_t *dereferenced_ptrs_load;
};
/* In tree-ssa-alias.c. */
enum escape_type is_escape_site (tree);
void update_mem_sym_stats_from_stmt (tree, tree, long, long);
/* In tree-ssa-structalias.c. */
extern void compute_points_to_sets (struct alias_info *);
extern void compute_points_to_sets (void);
extern void delete_points_to_sets (void);
extern void dump_constraint (FILE *, constraint_t);
extern void dump_constraints (FILE *);