* [pushed] c++: [[no_unique_address]] and virtual base [PR104139]
@ 2022-01-21 17:06 Jason Merrill
0 siblings, 0 replies; only message in thread
From: Jason Merrill @ 2022-01-21 17:06 UTC (permalink / raw)
To: gcc-patches
Fixing a thinko in my patch for 103681: when computing the size of a virtual
base, it would help to use its binfo instead of the one for the derived
class.
Tested x86_64-pc-linux-gnu, applying to trunk.
PR c++/104139
PR c++/103681
gcc/cp/ChangeLog:
* class.cc (end_of_class): Use base_binfo.
gcc/testsuite/ChangeLog:
* g++.dg/abi/no_unique_address2.C: Adjust to detect this on x86-64.
---
gcc/cp/class.cc | 4 +--
gcc/testsuite/g++.dg/abi/no_unique_address2.C | 27 +++++++++++++++++++
2 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc
index e5cc6f10e3b..5db3722ae46 100644
--- a/gcc/cp/class.cc
+++ b/gcc/cp/class.cc
@@ -6414,8 +6414,8 @@ end_of_class (tree t, eoc_mode mode)
{
if (mode == eoc_nv_or_dsize)
/* For dsize, don't count trailing empty bases. */
- offset = size_binop (PLUS_EXPR, BINFO_OFFSET (binfo),
- CLASSTYPE_SIZE_UNIT (BINFO_TYPE (binfo)));
+ offset = size_binop (PLUS_EXPR, BINFO_OFFSET (base_binfo),
+ CLASSTYPE_SIZE_UNIT (BINFO_TYPE (base_binfo)));
else
offset = end_of_base (base_binfo);
if (tree_int_cst_lt (result, offset))
diff --git a/gcc/testsuite/g++.dg/abi/no_unique_address2.C b/gcc/testsuite/g++.dg/abi/no_unique_address2.C
index bef6d5b43be..3bb3f76ac92 100644
--- a/gcc/testsuite/g++.dg/abi/no_unique_address2.C
+++ b/gcc/testsuite/g++.dg/abi/no_unique_address2.C
@@ -41,3 +41,30 @@ struct B4
#define SA(X) static_assert ((X), #X)
SA (sizeof (B2) == sizeof (B1));
SA (sizeof (B3) == sizeof (B4));
+
+namespace N2
+{
+ // C as big as _vptr to test PR c++/104139
+ struct C
+ {
+ long c;
+ };
+
+ struct D: virtual C
+ {
+ virtual void f();
+ };
+
+ struct B3: D
+ {
+ char c2;
+ };
+
+ struct B4
+ {
+ D d [[no_unique_address]];
+ char c2;
+ };
+
+ SA (sizeof (B3) == sizeof (B4));
+}
base-commit: 45cae5b6392496028f35c5948f7fae0af81d135b
--
2.27.0
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