/* True for variables whose size is not known or variable. */
unsigned int is_unknown_size_var:1;
+ /* True for (sub-)fields that represent a whole variable. */
+ unsigned int is_full_var : 1;
+
/* True if this is a heap variable. */
unsigned int is_heap_var:1;
ret->is_heap_var = false;
ret->is_special_var = false;
ret->is_unknown_size_var = false;
+ ret->is_full_var = false;
var = t;
if (TREE_CODE (var) == SSA_NAME)
var = SSA_NAME_VAR (var);
EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
{
- /* If this is a properly sized variable, only add offset if it's
- less than end. Otherwise, it is globbed to a single
- variable. */
+ varinfo_t vi = get_varinfo (i);
- if ((get_varinfo (i)->offset + offset) < get_varinfo (i)->fullsize)
+ /* If this is a variable with just one field just set its bit
+ in the result. */
+ if (vi->is_artificial_var
+ || vi->is_unknown_size_var
+ || vi->is_full_var)
+ bitmap_set_bit (result, i);
+ else
{
- unsigned HOST_WIDE_INT fieldoffset = get_varinfo (i)->offset + offset;
- varinfo_t v = first_vi_for_offset (get_varinfo (i), fieldoffset);
+ unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
+ varinfo_t v = first_vi_for_offset (vi, fieldoffset);
+ /* If the result is outside of the variable use the last field. */
if (!v)
- continue;
+ {
+ v = vi;
+ while (v->next != NULL)
+ v = v->next;
+ }
bitmap_set_bit (result, v->id);
- }
- else if (get_varinfo (i)->is_artificial_var
- || get_varinfo (i)->is_unknown_size_var)
- {
- bitmap_set_bit (result, i);
+ /* If the result is not exactly at fieldoffset include the next
+ field as well. See get_constraint_for_ptr_offset for more
+ rationale. */
+ if (v->offset != fieldoffset
+ && v->next != NULL)
+ bitmap_set_bit (result, v->next->id);
}
}
0. */
if (ninfo->is_special_var
|| ninfo->is_artificial_var
- || ninfo->is_unknown_size_var)
+ || ninfo->is_unknown_size_var
+ || ninfo->is_full_var)
{
*offset = 0;
return true;
sub-fields off. This avoids quadratic behavior. */
EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
{
- varinfo_t v = lookup_vi_for_tree (get_varinfo (j)->decl);
+ varinfo_t v = get_varinfo (j);
+ if (v->is_full_var)
+ continue;
+
+ v = lookup_vi_for_tree (v->decl);
if (v->next != NULL)
{
if (vars == NULL)
unsigned int t;
v = first_vi_for_offset (get_varinfo (j), fieldoffset);
+ /* If the access is outside of the variable we can ignore it. */
if (!v)
continue;
t = find (v->id);
unsigned HOST_WIDE_INT fieldoffset = jvi->offset + loff;
varinfo_t v;
- v = first_vi_for_offset (get_varinfo (j), fieldoffset);
- if (!v)
- continue;
+ v = get_varinfo (j);
+ if (!v->is_full_var)
+ {
+ v = first_vi_for_offset (v, fieldoffset);
+ /* If the access is outside of the variable we can ignore it. */
+ if (!v)
+ continue;
+ }
t = find (v->id);
if (bitmap_set_bit (get_varinfo (t)->solution, anything_id)
bitmap tmp;
v = first_vi_for_offset (get_varinfo (j), fieldoffset);
+ /* If the access is outside of the variable we can ignore it. */
if (!v)
continue;
t = find (v->id);
gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
- if (!use_field_sensitive)
- {
- t->rhs.offset = 0;
- t->lhs.offset = 0;
- }
-
/* ANYTHING == ANYTHING is pointless. */
if (lhs.var == anything_id && rhs.var == anything_id)
return;
}
+/* Get constraint expressions for offsetting PTR by OFFSET. Stores the
+ resulting constraint expressions in *RESULTS. */
+
+static void
+get_constraint_for_ptr_offset (tree ptr, tree offset,
+ VEC (ce_s, heap) **results)
+{
+ struct constraint_expr *c;
+ unsigned int j, n;
+ unsigned HOST_WIDE_INT rhsunitoffset, rhsoffset;
+
+ /* If we do not do field-sensitive PTA adding offsets to pointers
+ does not change the points-to solution. */
+ if (!use_field_sensitive)
+ {
+ get_constraint_for (ptr, results);
+ return;
+ }
+
+ /* If the offset is not a non-negative integer constant that fits
+ in a HOST_WIDE_INT, we have to fall back to a conservative
+ solution which includes all sub-fields of all pointed-to
+ variables of ptr.
+ ??? As we do not have the ability to express this, fall back
+ to anything. */
+ if (!host_integerp (offset, 1))
+ {
+ struct constraint_expr temp;
+ temp.var = anything_id;
+ temp.type = SCALAR;
+ temp.offset = 0;
+ VEC_safe_push (ce_s, heap, *results, &temp);
+ return;
+ }
+
+ /* Make sure the bit-offset also fits. */
+ rhsunitoffset = TREE_INT_CST_LOW (offset);
+ rhsoffset = rhsunitoffset * BITS_PER_UNIT;
+ if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
+ {
+ struct constraint_expr temp;
+ temp.var = anything_id;
+ temp.type = SCALAR;
+ temp.offset = 0;
+ VEC_safe_push (ce_s, heap, *results, &temp);
+ return;
+ }
+
+ get_constraint_for (ptr, results);
+ if (rhsoffset == 0)
+ return;
+
+ /* As we are eventually appending to the solution do not use
+ VEC_iterate here. */
+ n = VEC_length (ce_s, *results);
+ for (j = 0; j < n; j++)
+ {
+ varinfo_t curr;
+ c = VEC_index (ce_s, *results, j);
+ curr = get_varinfo (c->var);
+
+ if (c->type == ADDRESSOF
+ && !curr->is_full_var)
+ {
+ varinfo_t temp, curr = get_varinfo (c->var);
+
+ /* Search the sub-field which overlaps with the
+ pointed-to offset. As we deal with positive offsets
+ only, we can start the search from the current variable. */
+ temp = first_vi_for_offset (curr, curr->offset + rhsoffset);
+
+ /* If the result is outside of the variable we have to provide
+ a conservative result, as the variable is still reachable
+ from the resulting pointer (even though it technically
+ cannot point to anything). The last sub-field is such
+ a conservative result.
+ ??? If we always had a sub-field for &object + 1 then
+ we could represent this in a more precise way. */
+ if (temp == NULL)
+ {
+ temp = curr;
+ while (temp->next != NULL)
+ temp = temp->next;
+ continue;
+ }
+
+ /* If the found variable is not exactly at the pointed to
+ result, we have to include the next variable in the
+ solution as well. Otherwise two increments by offset / 2
+ do not result in the same or a conservative superset
+ solution. */
+ if (temp->offset != curr->offset + rhsoffset
+ && temp->next != NULL)
+ {
+ struct constraint_expr c2;
+ c2.var = temp->next->id;
+ c2.type = ADDRESSOF;
+ c2.offset = 0;
+ VEC_safe_push (ce_s, heap, *results, &c2);
+ }
+ c->var = temp->id;
+ c->offset = 0;
+ }
+ else if (c->type == ADDRESSOF
+ /* If this varinfo represents a full variable just use it. */
+ && curr->is_full_var)
+ c->offset = 0;
+ else
+ c->offset = rhsoffset;
+ }
+}
+
+
/* Given a COMPONENT_REF T, return the constraint_expr vector for it.
If address_p is true the result will be taken its address of. */
/* Pretend to take the address of the base, we'll take care of
adding the required subset of sub-fields below. */
get_constraint_for_1 (t, results, true);
- result = VEC_last (ce_s, *results);
-
gcc_assert (VEC_length (ce_s, *results) == 1);
+ result = VEC_last (ce_s, *results);
/* This can also happen due to weird offsetof type macros. */
if (TREE_CODE (t) != ADDR_EXPR && result->type == ADDRESSOF)
result->type = SCALAR;
- if (result->type == SCALAR)
+ if (result->type == SCALAR
+ && get_varinfo (result->var)->is_full_var)
+ /* For single-field vars do not bother about the offset. */
+ result->offset = 0;
+ else if (result->type == SCALAR)
{
/* In languages like C, you can access one past the end of an
array. You aren't allowed to dereference it, so we can
break;
}
}
- /* assert that we found *some* field there. The user couldn't be
- accessing *only* padding. */
- /* Still the user could access one past the end of an array
- embedded in a struct resulting in accessing *only* padding. */
- gcc_assert (VEC_length (ce_s, *results) >= 1
- || ref_contains_array_ref (orig_t));
+ /* If we are going to take the address of this field then
+ to be able to compute reachability correctly add at least
+ the last field of the variable. */
+ if (address_p
+ && VEC_length (ce_s, *results) == 0)
+ {
+ curr = get_varinfo (cexpr.var);
+ while (curr->next != NULL)
+ curr = curr->next;
+ cexpr.var = curr->id;
+ VEC_safe_push (ce_s, heap, *results, &cexpr);
+ }
+ else
+ /* Assert that we found *some* field there. The user couldn't be
+ accessing *only* padding. */
+ /* Still the user could access one past the end of an array
+ embedded in a struct resulting in accessing *only* padding. */
+ gcc_assert (VEC_length (ce_s, *results) >= 1
+ || ref_contains_array_ref (orig_t));
}
else if (bitmaxsize == 0)
{
VEC_safe_push (ce_s, heap, *results, &temp);
return;
}
- else
- {
- temp.var = anything_id;
- temp.type = SCALAR;
- temp.offset = 0;
- VEC_safe_push (ce_s, heap, *results, &temp);
- return;
- }
break;
- default:
- {
- temp.type = ADDRESSOF;
- temp.var = anything_id;
- temp.offset = 0;
- VEC_safe_push (ce_s, heap, *results, &temp);
- return;
- }
+ default:;
}
+ break;
}
case tcc_reference:
{
case COMPONENT_REF:
get_constraint_for_component_ref (t, results, address_p);
return;
- default:
- {
- temp.type = ADDRESSOF;
- temp.var = anything_id;
- temp.offset = 0;
- VEC_safe_push (ce_s, heap, *results, &temp);
- return;
- }
+ default:;
}
+ break;
}
case tcc_unary:
{
/* FALLTHRU */
}
- default:
- {
- temp.type = ADDRESSOF;
- temp.var = anything_id;
- temp.offset = 0;
- VEC_safe_push (ce_s, heap, *results, &temp);
- return;
- }
+ default:;
}
+ break;
+ }
+ case tcc_binary:
+ {
+ if (TREE_CODE (t) == POINTER_PLUS_EXPR)
+ {
+ get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
+ TREE_OPERAND (t, 1), results);
+ return;
+ }
+ break;
}
case tcc_exceptional:
{
get_constraint_for_1 (PHI_RESULT (t), results, address_p);
return;
}
- break;
case SSA_NAME:
{
get_constraint_for_ssa_var (t, results, address_p);
return;
}
- break;
- default:
- {
- temp.type = ADDRESSOF;
- temp.var = anything_id;
- temp.offset = 0;
- VEC_safe_push (ce_s, heap, *results, &temp);
- return;
- }
+ default:;
}
+ break;
}
case tcc_declaration:
{
get_constraint_for_ssa_var (t, results, address_p);
return;
}
- default:
- {
- temp.type = ADDRESSOF;
- temp.var = anything_id;
- temp.offset = 0;
- VEC_safe_push (ce_s, heap, *results, &temp);
- return;
- }
+ default:;
}
+
+ /* The default fallback is a constraint from anything. */
+ temp.type = ADDRESSOF;
+ temp.var = anything_id;
+ temp.offset = 0;
+ VEC_safe_push (ce_s, heap, *results, &temp);
}
/* Given a gimple tree T, return the constraint expression vector for it. */
}
}
-
-/* Handle pointer arithmetic EXPR when creating aliasing constraints.
- Expressions of the type PTR + CST can be handled in two ways:
-
- 1- If the constraint for PTR is ADDRESSOF for a non-structure
- variable, then we can use it directly because adding or
- subtracting a constant may not alter the original ADDRESSOF
- constraint (i.e., pointer arithmetic may not legally go outside
- an object's boundaries).
-
- 2- If the constraint for PTR is ADDRESSOF for a structure variable,
- then if CST is a compile-time constant that can be used as an
- offset, we can determine which sub-variable will be pointed-to
- by the expression.
-
- Return true if the expression is handled. For any other kind of
- expression, return false so that each operand can be added as a
- separate constraint by the caller. */
-
-static bool
-handle_ptr_arith (VEC (ce_s, heap) *lhsc, tree expr)
-{
- tree op0, op1;
- struct constraint_expr *c, *c2;
- unsigned int i = 0;
- unsigned int j = 0;
- VEC (ce_s, heap) *temp = NULL;
- unsigned HOST_WIDE_INT rhsunitoffset, rhsoffset;
-
- 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)));
-
- /* If the offset is not a non-negative integer constant that fits
- in a HOST_WIDE_INT, we cannot handle it here. */
- if (!host_integerp (op1, 1))
- return false;
-
- /* Make sure the bit-offset also fits. */
- rhsunitoffset = TREE_INT_CST_LOW (op1);
- rhsoffset = rhsunitoffset * BITS_PER_UNIT;
- if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
- return false;
-
- get_constraint_for (op0, &temp);
-
- for (i = 0; VEC_iterate (ce_s, lhsc, i, c); i++)
- for (j = 0; VEC_iterate (ce_s, temp, j, c2); j++)
- {
- if (c2->type == ADDRESSOF && rhsoffset != 0)
- {
- varinfo_t temp = get_varinfo (c2->var);
-
- /* An access one after the end of an array is valid,
- so simply punt on accesses we cannot resolve. */
- temp = first_vi_for_offset (temp, rhsoffset);
- if (temp == NULL)
- continue;
- c2->var = temp->id;
- c2->offset = 0;
- }
- else
- c2->offset = rhsoffset;
- process_constraint (new_constraint (*c, *c2));
- }
-
- VEC_free (ce_s, heap, temp);
-
- return true;
-}
-
/* Create a constraint ID = OP. */
static void
}
}
}
- /* Otherwise, just a regular assignment statement. */
- else if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
+ /* Otherwise, just a regular assignment statement. Only care about
+ operations with pointer result, others are dealt with as escape
+ points if they have pointer operands. */
+ else if (TREE_CODE (t) == GIMPLE_MODIFY_STMT
+ && could_have_pointers (GIMPLE_STMT_OPERAND (t, 0)))
{
tree lhsop = GIMPLE_STMT_OPERAND (t, 0);
tree rhsop = GIMPLE_STMT_OPERAND (t, 1);
- int i;
- if (AGGREGATE_TYPE_P (TREE_TYPE (lhsop))
- && AGGREGATE_TYPE_P (TREE_TYPE (rhsop)))
- {
- do_structure_copy (lhsop, rhsop);
- }
+ if (AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
+ do_structure_copy (lhsop, rhsop);
else
{
- /* Only care about operations with pointers, structures
- containing pointers, dereferences, and call expressions. */
- if (could_have_pointers (lhsop)
- || TREE_CODE (rhsop) == CALL_EXPR)
+ unsigned int j;
+ get_constraint_for (lhsop, &lhsc);
+ get_constraint_for (rhsop, &rhsc);
+ for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
{
- get_constraint_for (lhsop, &lhsc);
- switch (TREE_CODE_CLASS (TREE_CODE (rhsop)))
- {
- /* RHS that consist of unary operations,
- exceptional types, or bare decls/constants, get
- handled directly by get_constraint_for. */
- case tcc_reference:
- case tcc_declaration:
- case tcc_constant:
- case tcc_exceptional:
- case tcc_expression:
- case tcc_vl_exp:
- case tcc_unary:
- {
- unsigned int j;
-
- get_constraint_for (rhsop, &rhsc);
- for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
- {
- struct constraint_expr *c2;
- unsigned int k;
-
- for (k = 0; VEC_iterate (ce_s, rhsc, k, c2); k++)
- process_constraint (new_constraint (*c, *c2));
- }
-
- }
- break;
+ struct constraint_expr *c2;
+ unsigned int k;
- case tcc_binary:
- {
- /* For pointer arithmetic of the form
- PTR + CST, we can simply use PTR's
- constraint because pointer arithmetic is
- not allowed to go out of bounds. */
- if (handle_ptr_arith (lhsc, rhsop))
- break;
- }
- /* FALLTHRU */
-
- /* Otherwise, walk each operand. Notice that we
- can't use the operand interface because we need
- to process expressions other than simple operands
- (e.g. INDIRECT_REF, ADDR_EXPR, CALL_EXPR). */
- default:
- for (i = 0; i < TREE_OPERAND_LENGTH (rhsop); i++)
- {
- tree op = TREE_OPERAND (rhsop, i);
- unsigned int j;
-
- gcc_assert (VEC_length (ce_s, rhsc) == 0);
- get_constraint_for (op, &rhsc);
- for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
- {
- struct constraint_expr *c2;
- while (VEC_length (ce_s, rhsc) > 0)
- {
- c2 = VEC_last (ce_s, rhsc);
- process_constraint (new_constraint (*c, *c2));
- VEC_pop (ce_s, rhsc);
- }
- }
- }
- }
+ for (k = 0; VEC_iterate (ce_s, rhsc, k, c2); k++)
+ process_constraint (new_constraint (*c, *c2));
}
}
}
stats.total_vars++;
/* If it's varargs, we don't know how many arguments it has, so we
- can't do much.
- */
+ can't do much. */
if (is_varargs)
{
vi->fullsize = ~0;
VEC_safe_push (varinfo_t, heap, varmap, argvi);
argvi->offset = i;
argvi->size = 1;
+ argvi->is_full_var = true;
argvi->fullsize = vi->fullsize;
insert_into_field_list_sorted (vi, argvi);
stats.total_vars ++;
resultvi->offset = i;
resultvi->size = 1;
resultvi->fullsize = vi->fullsize;
+ resultvi->is_full_var = true;
insert_into_field_list_sorted (vi, resultvi);
stats.total_vars ++;
if (DECL_RESULT (decl))
vi->is_unknown_size_var = 1;
vi->fullsize = ~0;
vi->size = ~0;
+ vi->is_full_var = true;
VEC_free (fieldoff_s, heap, fieldstack);
return index;
}
stats.total_vars++;
}
}
+ else
+ vi->is_full_var = true;
VEC_free (fieldoff_s, heap, fieldstack);
static void
init_alias_vars (void)
{
+ use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
+
bitmap_obstack_initialize (&pta_obstack);
bitmap_obstack_initialize (&oldpta_obstack);
bitmap_obstack_initialize (&predbitmap_obstack);
projects / thirdparty / gcc.git / commitdiff
