Hi!
The following patch is an attempt to fix PLACEHOLDER_EXPR handling.
As e.g.
struct Y
{
static Y bar (Y y) { return y; }
int i;
int n = bar (Y{2,i}).m + bar {Y{2,i,i}).n;
int m = i;
};
is rejected - one can't use incomplete ctors which would need NSDMIs
until the class is defined, I believe PLACEHOLDER_EXPRs can't be arbitrarily
intermixed, rather some CONSTRUCTORs into which we've added the NSDMI
expressions can contain PLACEHOLDER_EXPRs and other PLACEHOLDER_EXPRs can be
only found inside such CONSTRUCTORs added earlier.
So, this patch adds a new flag on CONSTRUCTORs, which acts as a barrier
boundary for replace_placeholders, where we replace just PLACEHOLDER_EXPRs
from the outermost expressions and don't dive into CONSTRUCTORs into which
we've added other PLACEHOLDER_EXPRs - those will be handled later on
separately, by cp_gimplify_init_expr calling replace_placeholders.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2018-03-14 Jakub Jelinek <ja...@redhat.com>
PR c++/79937
PR c++/82410
* cp-tree.h (CONSTRUCTOR_PLACEHOLDER_BOUNDARY): Define.
(find_placeholder): Declare.
* tree.c (struct replace_placeholders_t): Add exp member.
(replace_placeholders_r): Don't walk into ctors with
CONSTRUCTOR_PLACEHOLDER_BOUNDARY flag set, unless they are equal to
d->exp.
(replace_placeholders): Initialize data.exp.
(find_placeholders_r, find_placeholders): New functions.
* typeck2.c (process_init_constructor_record,
process_init_constructor_union): Set CONSTRUCTOR_PLACEHOLDER_BOUNDARY
if adding NSDMI on which find_placeholder returns true.
* g++.dg/cpp1y/pr79937-1.C: New test.
* g++.dg/cpp1y/pr79937-2.C: New test.
* g++.dg/cpp1y/pr79937-3.C: New test.
* g++.dg/cpp1y/pr79937-4.C: New test.
* g++.dg/cpp1y/pr82410.C: New test.
--- gcc/cp/cp-tree.h.jj 2018-03-14 16:21:50.745925263 +0100
+++ gcc/cp/cp-tree.h 2018-03-14 15:57:51.171323825 +0100
@@ -425,6 +425,7 @@ extern GTY(()) tree cp_global_trees[CPTI
DECL_VTABLE_OR_VTT_P (in VAR_DECL)
FUNCTION_RVALUE_QUALIFIED (in FUNCTION_TYPE, METHOD_TYPE)
CALL_EXPR_REVERSE_ARGS (in CALL_EXPR, AGGR_INIT_EXPR)
+ CONSTRUCTOR_PLACEHOLDER_BOUNDARY (in CONSTRUCTOR)
6: IDENTIFIER_REPO_CHOSEN (in IDENTIFIER_NODE)
DECL_CONSTRUCTION_VTABLE_P (in VAR_DECL)
TYPE_MARKED_P (in _TYPE)
@@ -4144,6 +4145,12 @@ more_aggr_init_expr_args_p (const aggr_i
#define CONSTRUCTOR_C99_COMPOUND_LITERAL(NODE) \
(TREE_LANG_FLAG_3 (CONSTRUCTOR_CHECK (NODE)))
+/* True if this CONSTRUCTOR contains PLACEHOLDER_EXPRs referencing the
+ CONSTRUCTOR's type not nested inside another CONSTRUCTOR marked with
+ CONSTRUCTOR_PLACEHOLDER_BOUNDARY. */
+#define CONSTRUCTOR_PLACEHOLDER_BOUNDARY(NODE) \
+ (TREE_LANG_FLAG_5 (CONSTRUCTOR_CHECK (NODE)))
+
#define DIRECT_LIST_INIT_P(NODE) \
(BRACE_ENCLOSED_INITIALIZER_P (NODE) && CONSTRUCTOR_IS_DIRECT_INIT (NODE))
@@ -7021,6 +7028,7 @@ extern tree array_type_nelts_top (tree)
extern tree break_out_target_exprs (tree);
extern tree build_ctor_subob_ref (tree, tree, tree);
extern tree replace_placeholders (tree, tree, bool * = NULL);
+extern bool find_placeholders (tree);
extern tree get_type_decl (tree);
extern tree decl_namespace_context (tree);
extern bool decl_anon_ns_mem_p (const_tree);
--- gcc/cp/tree.c.jj 2018-03-14 11:49:58.926816421 +0100
+++ gcc/cp/tree.c 2018-03-14 16:24:29.036987505 +0100
@@ -3096,6 +3096,7 @@ build_ctor_subob_ref (tree index, tree t
struct replace_placeholders_t
{
tree obj; /* The object to be substituted for a PLACEHOLDER_EXPR. */
+ tree exp; /* The outermost exp. */
bool seen; /* Whether we've encountered a PLACEHOLDER_EXPR. */
hash_set<tree> *pset; /* To avoid walking same trees multiple times.
*/
};
@@ -3134,7 +3135,12 @@ replace_placeholders_r (tree* t, int* wa
{
constructor_elt *ce;
vec<constructor_elt,va_gc> *v = CONSTRUCTOR_ELTS (*t);
- if (d->pset->add (*t))
+ /* Don't walk into CONSTRUCTOR_PLACEHOLDER_BOUNDARY ctors
+ other than the d->exp one, those have PLACEHOLDER_EXPRs
+ related to another object. */
+ if ((CONSTRUCTOR_PLACEHOLDER_BOUNDARY (*t)
+ && *t != d->exp)
+ || d->pset->add (*t))
{
*walk_subtrees = false;
return NULL_TREE;
@@ -3192,16 +3198,70 @@ replace_placeholders (tree exp, tree obj
return exp;
tree *tp = &exp;
- hash_set<tree> pset;
- replace_placeholders_t data = { obj, false, &pset };
+ /* Use exp instead of *(type *)&exp. */
+ while (TREE_CODE (exp) == INDIRECT_REF)
+ {
+ tree t = TREE_OPERAND (exp, 0);
+ STRIP_NOPS (t);
+ if (TREE_CODE (t) == ADDR_EXPR
+ && (t = TREE_OPERAND (t, 0))
+ && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (exp),
+ TREE_TYPE (t)))
+ exp = t;
+ else
+ break;
+ }
if (TREE_CODE (exp) == TARGET_EXPR)
tp = &TARGET_EXPR_INITIAL (exp);
+ hash_set<tree> pset;
+ replace_placeholders_t data = { obj, *tp, false, &pset };
cp_walk_tree (tp, replace_placeholders_r, &data, NULL);
if (seen_p)
*seen_p = data.seen;
return exp;
}
+/* Callback function for find_placeholders. */
+
+static tree
+find_placeholders_r (tree *t, int *walk_subtrees, void *)
+{
+ if (TYPE_P (*t) || TREE_CONSTANT (*t))
+ {
+ *walk_subtrees = false;
+ return NULL_TREE;
+ }
+
+ switch (TREE_CODE (*t))
+ {
+ case PLACEHOLDER_EXPR:
+ return *t;
+
+ case CONSTRUCTOR:
+ if (CONSTRUCTOR_PLACEHOLDER_BOUNDARY (*t))
+ *walk_subtrees = false;
+ break;
+
+ default:
+ break;
+ }
+
+ return NULL_TREE;
+}
+
+/* Return true if EXP contains a PLACEHOLDER_EXPR. Don't walk into
+ ctors with CONSTRUCTOR_PLACEHOLDER_BOUNDARY flag set. */
+
+bool
+find_placeholders (tree exp)
+{
+ /* This is only relevant for C++14. */
+ if (cxx_dialect < cxx14)
+ return false;
+
+ return cp_walk_tree_without_duplicates (&exp, find_placeholders_r, NULL);
+}
+
/* Similar to `build_nt', but for template definitions of dependent
expressions */
--- gcc/cp/typeck2.c.jj 2018-03-14 16:25:49.622019191 +0100
+++ gcc/cp/typeck2.c 2018-03-14 16:02:36.093441530 +0100
@@ -1470,6 +1470,9 @@ process_init_constructor_record (tree ty
}
/* C++14 aggregate NSDMI. */
next = get_nsdmi (field, /*ctor*/false, complain);
+ if (!CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init)
+ && find_placeholders (next))
+ CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init) = 1;
}
else if (type_build_ctor_call (TREE_TYPE (field)))
{
@@ -1608,10 +1611,11 @@ process_init_constructor_union (tree typ
if (TREE_CODE (field) == FIELD_DECL
&& DECL_INITIAL (field) != NULL_TREE)
{
- CONSTRUCTOR_APPEND_ELT (CONSTRUCTOR_ELTS (init),
- field,
- get_nsdmi (field, /*in_ctor=*/false,
- complain));
+ tree val = get_nsdmi (field, /*in_ctor=*/false, complain);
+ if (!CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init)
+ && find_placeholders (val))
+ CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init) = 1;
+ CONSTRUCTOR_APPEND_ELT (CONSTRUCTOR_ELTS (init), field, val);
break;
}
}
--- gcc/testsuite/g++.dg/cpp1y/pr79937-1.C.jj 2018-03-14 14:32:12.230097853
+0100
+++ gcc/testsuite/g++.dg/cpp1y/pr79937-1.C 2018-03-14 14:32:12.230097853
+0100
@@ -0,0 +1,23 @@
+// PR c++/79937
+// { dg-do run { target c++14 } }
+
+struct C {};
+
+struct X {
+ unsigned i;
+ unsigned n = i;
+};
+
+C
+bar (X x)
+{
+ if (x.i != 1 || x.n != 1)
+ __builtin_abort ();
+ return {};
+}
+
+int
+main ()
+{
+ C c = bar (X {1});
+}
--- gcc/testsuite/g++.dg/cpp1y/pr79937-2.C.jj 2018-03-14 14:32:12.231097853
+0100
+++ gcc/testsuite/g++.dg/cpp1y/pr79937-2.C 2018-03-14 14:32:12.231097853
+0100
@@ -0,0 +1,24 @@
+// PR c++/79937
+// { dg-do run { target c++14 } }
+
+struct C {};
+
+struct X {
+ unsigned i;
+ unsigned n = i;
+ unsigned m = i;
+};
+
+C
+bar (X x)
+{
+ if (x.i != 1 || x.n != 2 || x.m != 1)
+ __builtin_abort ();
+ return {};
+}
+
+int
+main ()
+{
+ C c = bar (X {1, X {2}.n});
+}
--- gcc/testsuite/g++.dg/cpp1y/pr79937-3.C.jj 2018-03-14 14:32:12.231097853
+0100
+++ gcc/testsuite/g++.dg/cpp1y/pr79937-3.C 2018-03-14 14:32:12.231097853
+0100
@@ -0,0 +1,24 @@
+// PR c++/79937
+// { dg-do run { target c++14 } }
+
+struct X {
+ unsigned i;
+ unsigned n = i;
+ unsigned m = i;
+};
+
+X
+bar (X x)
+{
+ if (x.i != 1 || x.n != 2 || x.m != 1)
+ __builtin_abort ();
+ return x;
+}
+
+int
+main ()
+{
+ X x = bar (X {1, X {2}.n});
+ if (x.i != 1 || x.n != 2 || x.m != 1)
+ __builtin_abort ();
+}
--- gcc/testsuite/g++.dg/cpp1y/pr79937-4.C.jj 2018-03-14 16:14:50.842757308
+0100
+++ gcc/testsuite/g++.dg/cpp1y/pr79937-4.C 2018-03-14 16:14:45.761755127
+0100
@@ -0,0 +1,32 @@
+// PR c++/79937
+// { dg-do run { target c++14 } }
+
+struct X {
+ unsigned i;
+ unsigned n = i;
+};
+
+X
+bar (X x)
+{
+ return x;
+}
+
+struct Y
+{
+ static Y bar (Y y) { return y; }
+ unsigned i;
+ unsigned n = bar (Y{2,i}).n;
+};
+
+int
+main ()
+{
+ X x { 1, bar (X{2}).n };
+ if (x.n != 2)
+ __builtin_abort ();
+
+ Y y { 1 };
+ if (y.n != 1)
+ __builtin_abort ();
+}
--- gcc/testsuite/g++.dg/cpp1y/pr82410.C.jj 2018-03-14 16:20:07.180884544
+0100
+++ gcc/testsuite/g++.dg/cpp1y/pr82410.C 2018-03-14 16:20:01.626882356
+0100
@@ -0,0 +1,16 @@
+// PR c++/82410
+// { dg-do compile { target c++14 } }
+
+int
+main ()
+{
+ struct A {};
+ struct S
+ {
+ int & p;
+ int x = p;
+ operator A () { return {}; }
+ };
+ int l;
+ [] (A) {} (S{l});
+}
Jakub
