On 12/17/24 12:08 PM, Marek Polacek wrote:
On Tue, Dec 17, 2024 at 10:36:09AM -0500, Jason Merrill wrote:
On 12/16/24 6:48 PM, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/branches?
-- >8 --
This crash started with my r12-7803 but I believe the problem lies
elsewhere.
build_vec_init has cleanup_flags whose purpose is -- if I grok this
correctly -- to avoid destructing an object multiple times. Let's
say we are initializing an array of A. Then we might end up in
a scenario similar to initlist-eh1.C:
try
{
call A::A in a loop
// #0
try
{
call a fn using the array
}
finally
{
// #1
call A::~A in a loop
}
}
catch
{
// #2
call A::~A in a loop
}
cleanup_flags makes us emit a statement like
D.3048 = 2;
at #0 to disable performing the cleanup at #2, since #1 will take
care of the destruction of the array.
But if we are not emitting the loop because we can use a constant
initializer (and use a single { a, b, ...}), we shouldn't generate
the statement resetting the iterator to its initial value. Otherwise
we crash in gimplify_var_or_parm_decl because it gets the stray decl
D.3048.
PR c++/117985
gcc/cp/ChangeLog:
* init.cc (build_vec_init): Clear CLEANUP_FLAGS if we're not
generating the loop.
truncate seems dangerous, there might be other things in cleanup_flags that
we want to leave alone. I think it would be safer to assert that the last
element in the vec is iterator, and then pop it.
Yeah, that does sound much safer. Like so?
OK.
dg.exp passed.
-- >8 --
This crash started with my r12-7803 but I believe the problem lies
elsewhere.
build_vec_init has cleanup_flags whose purpose is -- if I grok this
correctly -- to avoid destructing an object multiple times. Let's
say we are initializing an array of A. Then we might end up in
a scenario similar to initlist-eh1.C:
try
{
call A::A in a loop
// #0
try
{
call a fn using the array
}
finally
{
// #1
call A::~A in a loop
}
}
catch
{
// #2
call A::~A in a loop
}
cleanup_flags makes us emit a statement like
D.3048 = 2;
at #0 to disable performing the cleanup at #2, since #1 will take
care of the destruction of the array.
But if we are not emitting the loop because we can use a constant
initializer (and use a single { a, b, ...}), we shouldn't generate
the statement resetting the iterator to its initial value. Otherwise
we crash in gimplify_var_or_parm_decl because it gets the stray decl
D.3048.
PR c++/117985
gcc/cp/ChangeLog:
* init.cc (build_vec_init): Pop CLEANUP_FLAGS if we're not
generating the loop.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/initlist-array23.C: New test.
* g++.dg/cpp0x/initlist-array24.C: New test.
---
gcc/cp/init.cc | 9 ++++++
gcc/testsuite/g++.dg/cpp0x/initlist-array23.C | 28 +++++++++++++++++++
gcc/testsuite/g++.dg/cpp0x/initlist-array24.C | 27 ++++++++++++++++++
3 files changed, 64 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist-array23.C
create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist-array24.C
diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index ae516407c92..7dcc1152c72 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -5109,6 +5109,15 @@ build_vec_init (tree base, tree maxindex, tree init,
{
if (!saw_non_const)
{
+ /* If we're not generating the loop, we don't need to reset the
+ iterator. */
+ if (cleanup_flags
+ && !vec_safe_is_empty (*cleanup_flags))
+ {
+ auto l = (*cleanup_flags)->last ();
+ gcc_assert (TREE_PURPOSE (l) == iterator);
+ (*cleanup_flags)->pop ();
+ }
tree const_init = build_constructor (atype, const_vec);
return build2 (INIT_EXPR, atype, obase, const_init);
}
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-array23.C
b/gcc/testsuite/g++.dg/cpp0x/initlist-array23.C
new file mode 100644
index 00000000000..cda2afb9fcc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist-array23.C
@@ -0,0 +1,28 @@
+// PR c++/117985
+// { dg-do compile { target c++11 } }
+
+struct _Vector_impl {
+ constexpr
+ _Vector_impl() {}
+};
+struct _Vector_base {
+ ~_Vector_base();
+ _Vector_impl _M_impl;
+};
+struct vector : private _Vector_base {};
+struct string {
+ string();
+};
+struct VEC {
+ vector pane{};
+};
+struct FOO {
+ VEC screen[1]{};
+ string debug_name;
+};
+
+int
+main ()
+{
+ FOO{};
+}
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-array24.C
b/gcc/testsuite/g++.dg/cpp0x/initlist-array24.C
new file mode 100644
index 00000000000..7dda00d5c0b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist-array24.C
@@ -0,0 +1,27 @@
+// PR c++/117985
+// { dg-do compile { target c++20 } }
+
+struct _Vector_impl {
+ constexpr _Vector_impl() {}
+};
+struct _Vector_base {
+ constexpr ~_Vector_base() {}
+ _Vector_impl _M_impl;
+};
+struct vector : private _Vector_base {};
+struct string {
+ string();
+};
+struct VEC {
+ vector pane{};
+};
+struct FOO {
+ VEC screen[1]{};
+ string debug_name;
+};
+
+int
+main ()
+{
+ FOO{};
+}
base-commit: d17b09c07a1da0e3950718aabc2cbdb90cae402b
