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* [gcc r12-6331] c++: keep destroying array after one dtor throws [PR66451]
@ 2022-01-07 0:25 Jason Merrill
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From: Jason Merrill @ 2022-01-07 0:25 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:2fbc45486e13facfeb05bd6ddf70ff9973a30a3c
commit r12-6331-g2fbc45486e13facfeb05bd6ddf70ff9973a30a3c
Author: Jason Merrill <jason@redhat.com>
Date: Wed Jan 5 09:49:37 2022 -0500
c++: keep destroying array after one dtor throws [PR66451]
When we're cleaning up an array, if one destructor throws, we should still
try to clean up the rest of the array. We can use TRY_CATCH_EXPR for this,
instead of a TARGET_EXPR like my other recent patches, because a destructor
call can't involve any temporaries that need to live longer.
I thought about only doing this when we call build_vec_delete_1 from
build_vec_init, but it seems appropriate for delete-expressions as well;
we've said that the array's lifetime is over, it makes sense to keep trying
to destroy it. The standard isn't clear, but clang seems to agree with me.
PR c++/66451
gcc/cp/ChangeLog:
* init.c (build_vec_delete_1): Handle throwing dtor.
(build_vec_init): Tell it we're in a cleanup already.
gcc/testsuite/ChangeLog:
* g++.dg/eh/array3.C: New test.
* g++.dg/eh/array1.C: Mark destructor as throw().
* g++.dg/ipa/devirt-40.C: Likewise.
* g++.dg/warn/pr83054.C: Likewise.
* g++.dg/eh/delete1.C: Shorten array to one element.
Diff:
---
gcc/cp/init.c | 18 ++++++++++++++--
gcc/testsuite/g++.dg/eh/array1.C | 8 +++++++-
gcc/testsuite/g++.dg/eh/array3.C | 40 ++++++++++++++++++++++++++++++++++++
gcc/testsuite/g++.dg/eh/delete1.C | 2 +-
gcc/testsuite/g++.dg/ipa/devirt-40.C | 10 ++++++++-
gcc/testsuite/g++.dg/warn/pr83054.C | 9 +++++++-
6 files changed, 81 insertions(+), 6 deletions(-)
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 7c7b8104026..df63e618394 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -4006,7 +4006,8 @@ build_new (location_t loc, vec<tree, va_gc> **placement, tree type,
static tree
build_vec_delete_1 (location_t loc, tree base, tree maxindex, tree type,
special_function_kind auto_delete_vec,
- int use_global_delete, tsubst_flags_t complain)
+ int use_global_delete, tsubst_flags_t complain,
+ bool in_cleanup = false)
{
tree virtual_size;
tree ptype = build_pointer_type (type = complete_type (type));
@@ -4109,6 +4110,18 @@ build_vec_delete_1 (location_t loc, tree base, tree maxindex, tree type,
body = build_compound_expr (loc, body, tmp);
loop = build1 (LOOP_EXPR, void_type_node, body);
+
+ /* If one destructor throws, keep trying to clean up the rest, unless we're
+ already in a build_vec_init cleanup. */
+ if (flag_exceptions && !in_cleanup && !expr_noexcept_p (tmp, tf_none))
+ {
+ loop = build2 (TRY_CATCH_EXPR, void_type_node, loop,
+ unshare_expr (loop));
+ /* Tell honor_protect_cleanup_actions to discard this on the
+ exceptional path. */
+ TRY_CATCH_IS_CLEANUP (loop) = true;
+ }
+
loop = build_compound_expr (loc, tbase_init, loop);
no_destructor:
@@ -4490,7 +4503,8 @@ build_vec_init (tree base, tree maxindex, tree init,
e = build_vec_delete_1 (input_location, rval, m,
inner_elt_type, sfk_complete_destructor,
- /*use_global_delete=*/0, complain);
+ /*use_global_delete=*/0, complain,
+ /*in_cleanup*/true);
if (e == error_mark_node)
errors = true;
TARGET_EXPR_CLEANUP (iterator_targ) = e;
diff --git a/gcc/testsuite/g++.dg/eh/array1.C b/gcc/testsuite/g++.dg/eh/array1.C
index 30b035cfc52..79d62ad5058 100644
--- a/gcc/testsuite/g++.dg/eh/array1.C
+++ b/gcc/testsuite/g++.dg/eh/array1.C
@@ -2,10 +2,16 @@
// rather than one for each element.
// { dg-options "-fdump-tree-gimple" }
+#if __cplusplus < 201100L
+#define NOTHROW throw()
+#else
+#define NOTHROW noexcept
+#endif
+
struct A
{
A();
- ~A();
+ ~A() NOTHROW;
};
void f()
diff --git a/gcc/testsuite/g++.dg/eh/array3.C b/gcc/testsuite/g++.dg/eh/array3.C
new file mode 100644
index 00000000000..547541b5dc3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/eh/array3.C
@@ -0,0 +1,40 @@
+// PR c++/66451
+// { dg-do run }
+
+#if __cplusplus > 201100L
+#define THROWING noexcept(false)
+#else
+#define THROWING
+#endif
+
+extern "C" void abort();
+
+int c;
+struct A
+{
+ int a;
+
+ A(int new_a) : a(new_a) { ++c; }
+ A(const A&); // not defined
+ ~A() THROWING
+ {
+ --c;
+ if(a==4)
+ throw a;
+ }
+};
+
+struct B
+{
+ A a[2];
+ ~B() { }
+};
+
+int sink;
+int main()
+{
+ try {
+ B b = {3,4};
+ } catch(...) { }
+ if (c != 0) abort();
+}
diff --git a/gcc/testsuite/g++.dg/eh/delete1.C b/gcc/testsuite/g++.dg/eh/delete1.C
index 1727a74ff36..92ed646ef2c 100644
--- a/gcc/testsuite/g++.dg/eh/delete1.C
+++ b/gcc/testsuite/g++.dg/eh/delete1.C
@@ -69,7 +69,7 @@ int ary ()
{
deleted = 0;
- Baz *p = new Baz[5];
+ Baz *p = new Baz[1];
try { delete[] p; }
catch (...) { return deleted != 1;}
return 1;
diff --git a/gcc/testsuite/g++.dg/ipa/devirt-40.C b/gcc/testsuite/g++.dg/ipa/devirt-40.C
index 32e0d22c0e7..31fe1504cb8 100644
--- a/gcc/testsuite/g++.dg/ipa/devirt-40.C
+++ b/gcc/testsuite/g++.dg/ipa/devirt-40.C
@@ -1,4 +1,12 @@
/* { dg-options "-O2 -fdump-tree-fre3-details" } */
+
+// A throwing dtor in C++98 mode changes the results.
+#if __cplusplus < 201100L
+#define NOTHROW throw()
+#else
+#define NOTHROW noexcept
+#endif
+
typedef enum
{
} UErrorCode;
@@ -6,7 +14,7 @@ class UnicodeString
{
public:
UnicodeString ();
- virtual ~UnicodeString ();
+ virtual ~UnicodeString () NOTHROW;
};
class A
{
diff --git a/gcc/testsuite/g++.dg/warn/pr83054.C b/gcc/testsuite/g++.dg/warn/pr83054.C
index 506c9609b90..5285f94acee 100644
--- a/gcc/testsuite/g++.dg/warn/pr83054.C
+++ b/gcc/testsuite/g++.dg/warn/pr83054.C
@@ -2,6 +2,13 @@
// { dg-options "-O3 -Wsuggest-final-types" }
// { dg-do compile }
+// A throwing dtor in C++98 mode changes the warning.
+#if __cplusplus < 201100L
+#define NOTHROW throw()
+#else
+#define NOTHROW noexcept
+#endif
+
extern "C" int printf (const char *, ...);
struct foo // { dg-warning "final would enable devirtualization of 5 calls" }
{
@@ -12,7 +19,7 @@ struct foo // { dg-warning "final would enable devirtualization of 5 calls" }
x = count++;
printf("this %d = %x\n", x, (void *)this);
}
- virtual ~foo () {
+ virtual ~foo () NOTHROW {
printf("this %d = %x\n", x, (void *)this);
--count;
}
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2022-01-07 0:25 [gcc r12-6331] c++: keep destroying array after one dtor throws [PR66451] Jason Merrill
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