https://gcc.gnu.org/g:bfc9520eab16379aa47121d336bfd4d38c6d040a
commit r13-9480-gbfc9520eab16379aa47121d336bfd4d38c6d040a
Author: Iain Buclaw <ibuc...@gdcproject.org>
Date: Sat Mar 29 23:16:25 2025 +0100
d: Fix error with -Warray-bounds and -O2 [PR117002]
The record layout of class types in D don't get any tail padding, so it
is possible for the `classInstanceSize' to not be a multiple of the
`classInstanceAlignment'.
Rather than setting the instance alignment on the underlying
RECORD_TYPE, instead give the type an alignment of 1, which will mark it
as TYPE_PACKED. The value of `classInstanceAlignment' is instead
applied to the DECL_ALIGN of both the static `init' symbol, and the
stack allocated variable used when generating `new' for a `scope' class.
PR d/117002
gcc/d/ChangeLog:
* decl.cc (aggregate_initializer_decl): Set explicit decl alignment
of
class instance.
* expr.cc (ExprVisitor::visit (NewExp *)): Likewise.
* types.cc (TypeVisitor::visit (TypeClass *)): Mark the record type
of
classes as packed.
gcc/testsuite/ChangeLog:
* gdc.dg/torture/pr117002.d: New test.
(cherry picked from commit 9fadadbbbc2b5352e5e70e0e1a9be9b447176913)
Diff:
---
gcc/d/decl.cc | 6 ++++++
gcc/d/expr.cc | 2 ++
gcc/d/types.cc | 3 ++-
gcc/testsuite/gdc.dg/torture/pr117002.d | 28 ++++++++++++++++++++++++++++
4 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/gcc/d/decl.cc b/gcc/d/decl.cc
index deba3335a6a8..945f075cd44e 100644
--- a/gcc/d/decl.cc
+++ b/gcc/d/decl.cc
@@ -2382,6 +2382,12 @@ aggregate_initializer_decl (AggregateDeclaration *decl)
SET_DECL_ALIGN (sinit, sd->alignment.get () * BITS_PER_UNIT);
DECL_USER_ALIGN (sinit) = true;
}
+ else if (sd == NULL)
+ {
+ /* Alignment of class is determined its biggest field alignment. */
+ SET_DECL_ALIGN (sinit, decl->alignsize * BITS_PER_UNIT);
+ DECL_USER_ALIGN (sinit) = true;
+ }
decl->sinit = sinit;
return sinit;
diff --git a/gcc/d/expr.cc b/gcc/d/expr.cc
index 5d91349bf5b5..6ed9554af1bf 100644
--- a/gcc/d/expr.cc
+++ b/gcc/d/expr.cc
@@ -2261,6 +2261,8 @@ public:
storage class, then the instance is allocated on the stack
rather than the heap or using the class specific allocator. */
tree var = build_local_temp (TREE_TYPE (type));
+ SET_DECL_ALIGN (var, cd->alignsize * BITS_PER_UNIT);
+ DECL_USER_ALIGN (var) = 1;
new_call = build_nop (type, build_address (var));
setup_exp = modify_expr (var, aggregate_initializer_decl (cd));
}
diff --git a/gcc/d/types.cc b/gcc/d/types.cc
index 32b322c87190..0a8679756b0a 100644
--- a/gcc/d/types.cc
+++ b/gcc/d/types.cc
@@ -1278,7 +1278,8 @@ public:
build_type_decl (basetype, t->sym);
set_visibility_for_decl (basetype, t->sym);
apply_user_attributes (t->sym, basetype);
- finish_aggregate_type (t->sym->structsize, t->sym->alignsize, basetype);
+ /* The underlying record type of classes are packed. */
+ finish_aggregate_type (t->sym->structsize, 1, basetype);
/* Classes only live in memory, so always set the TREE_ADDRESSABLE bit. */
for (tree tv = basetype; tv != NULL_TREE; tv = TYPE_NEXT_VARIANT (tv))
diff --git a/gcc/testsuite/gdc.dg/torture/pr117002.d
b/gcc/testsuite/gdc.dg/torture/pr117002.d
new file mode 100644
index 000000000000..5b8c19e5b12f
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/torture/pr117002.d
@@ -0,0 +1,28 @@
+// { dg-do compile }
+// { dg-additional-options "-Warray-bounds" }
+extern(C++) class C117002
+{
+ ubyte[4] not_multiple_of_8;
+}
+
+int pr117002a(void *p)
+{
+ auto init = __traits(initSymbol, C117002);
+ if (init.ptr + init.length <= p)
+ return 1;
+ return 0;
+}
+
+void pr117002b(void *p)
+{
+ auto init = __traits(initSymbol, C117002);
+ p[0 .. init.length] = init[];
+}
+
+void pr117002c()
+{
+ scope var = new C117002;
+ void *p = cast(void*)var;
+ auto init = __traits(initSymbol, C117002);
+ p[0 .. __traits(classInstanceSize, C117002)] = init[];
+}
