* [PATCH] c++: goto entering scope of obj w/ non-trivial dtor [PR103091]
@ 2023-05-05 17:36 Patrick Palka
2023-05-05 18:18 ` Jason Merrill
0 siblings, 1 reply; 2+ messages in thread
From: Patrick Palka @ 2023-05-05 17:36 UTC (permalink / raw)
To: gcc-patches; +Cc: jason, Patrick Palka
It seems DR 2256 permitted goto to cross the initialization of a
trivially initialized object with a non-trivial destructor. We
already supported this as an -fpermissive extension, so this patch
just makes us unconditionally support this.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
for trunk?
DR 2256
PR c++/103091
gcc/cp/ChangeLog:
* decl.cc (decl_jump_unsafe): Return bool instead of int.
Don't consider TYPE_HAS_NONTRIVIAL_DESTRUCTOR.
(check_previous_goto_1): Simplify now that decl_jump_unsafe
returns bool instead of int.
(check_goto): Likewise.
gcc/testsuite/ChangeLog:
* g++.old-deja/g++.other/init9.C: Don't expect diagnostics for
goto made valid by DR 2256.
* g++.dg/init/goto4.C: New test.
---
gcc/cp/decl.cc | 56 ++++++--------------
gcc/testsuite/g++.dg/init/goto4.C | 22 ++++++++
gcc/testsuite/g++.old-deja/g++.other/init9.C | 7 +--
3 files changed, 42 insertions(+), 43 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/init/goto4.C
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 71d33d2b7a4..23a2b2fef0b 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -69,7 +69,7 @@ enum bad_spec_place {
static const char *redeclaration_error_message (tree, tree);
-static int decl_jump_unsafe (tree);
+static bool decl_jump_unsafe (tree);
static void require_complete_types_for_parms (tree);
static tree grok_reference_init (tree, tree, tree, int);
static tree grokvardecl (tree, tree, tree, const cp_decl_specifier_seq *,
@@ -3548,10 +3548,9 @@ declare_local_label (tree id)
return ent ? ent->label_decl : NULL_TREE;
}
-/* Returns nonzero if it is ill-formed to jump past the declaration of
- DECL. Returns 2 if it's also a real problem. */
+/* Returns true if it is ill-formed to jump past the declaration of DECL. */
-static int
+static bool
decl_jump_unsafe (tree decl)
{
/* [stmt.dcl]/3: A program that jumps from a point where a local variable
@@ -3562,18 +3561,11 @@ decl_jump_unsafe (tree decl)
preceding types and is declared without an initializer (8.5). */
tree type = TREE_TYPE (decl);
- if (!VAR_P (decl) || TREE_STATIC (decl)
- || type == error_mark_node)
- return 0;
-
- if (DECL_NONTRIVIALLY_INITIALIZED_P (decl)
- || variably_modified_type_p (type, NULL_TREE))
- return 2;
-
- if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
- return 1;
-
- return 0;
+ return (type != error_mark_node
+ && VAR_P (decl)
+ && !TREE_STATIC (decl)
+ && (DECL_NONTRIVIALLY_INITIALIZED_P (decl)
+ || variably_modified_type_p (type, NULL_TREE)));
}
/* A subroutine of check_previous_goto_1 and check_goto to identify a branch
@@ -3625,27 +3617,18 @@ check_previous_goto_1 (tree decl, cp_binding_level* level, tree names,
new_decls = (DECL_P (new_decls) ? DECL_CHAIN (new_decls)
: TREE_CHAIN (new_decls)))
{
- int problem = decl_jump_unsafe (new_decls);
+ bool problem = decl_jump_unsafe (new_decls);
if (! problem)
continue;
if (!identified)
{
- complained = identify_goto (decl, input_location, locus,
- problem > 1
- ? DK_ERROR : DK_PERMERROR);
+ complained = identify_goto (decl, input_location, locus, DK_ERROR);
identified = 1;
}
if (complained)
- {
- if (problem > 1)
- inform (DECL_SOURCE_LOCATION (new_decls),
- " crosses initialization of %q#D", new_decls);
- else
- inform (DECL_SOURCE_LOCATION (new_decls),
- " enters scope of %q#D, which has "
- "non-trivial destructor", new_decls);
- }
+ inform (DECL_SOURCE_LOCATION (new_decls),
+ " crosses initialization of %q#D", new_decls);
}
if (b == level)
@@ -3790,9 +3773,9 @@ check_goto (tree decl)
FOR_EACH_VEC_SAFE_ELT (ent->bad_decls, ix, bad)
{
- int u = decl_jump_unsafe (bad);
+ bool problem = decl_jump_unsafe (bad);
- if (u > 1 && DECL_ARTIFICIAL (bad))
+ if (problem && DECL_ARTIFICIAL (bad))
{
/* Can't skip init of __exception_info. */
if (identified == 1)
@@ -3806,15 +3789,8 @@ check_goto (tree decl)
saw_catch = true;
}
else if (complained)
- {
- if (u > 1)
- inform (DECL_SOURCE_LOCATION (bad),
- " skips initialization of %q#D", bad);
- else
- inform (DECL_SOURCE_LOCATION (bad),
- " enters scope of %q#D which has "
- "non-trivial destructor", bad);
- }
+ inform (DECL_SOURCE_LOCATION (bad),
+ " skips initialization of %q#D", bad);
}
if (complained)
diff --git a/gcc/testsuite/g++.dg/init/goto4.C b/gcc/testsuite/g++.dg/init/goto4.C
new file mode 100644
index 00000000000..90ae52e6455
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/goto4.C
@@ -0,0 +1,22 @@
+// DR 2256
+// PR c++/103091
+// { dg-do run }
+
+static int i;
+
+struct A {
+ ~A() { ++i;}
+};
+
+void f() {
+ goto L;
+ A a;
+L:
+ return;
+}
+
+int main() {
+ f();
+ if (i != 1)
+ __builtin_abort();
+}
diff --git a/gcc/testsuite/g++.old-deja/g++.other/init9.C b/gcc/testsuite/g++.old-deja/g++.other/init9.C
index 46d99028bdd..0194cd1b49a 100644
--- a/gcc/testsuite/g++.old-deja/g++.other/init9.C
+++ b/gcc/testsuite/g++.old-deja/g++.other/init9.C
@@ -24,9 +24,10 @@ struct X {
};
void b() {
- goto bar; // { dg-message "" } jump from here
- X x; // { dg-message "" } jump crosses initialization
- bar: // { dg-error "" } jump to here
+ // This was ill-formed until DR 2256.
+ goto bar;
+ X x;
+ bar:
;
}
--
2.40.1.476.g69c786637d
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] c++: goto entering scope of obj w/ non-trivial dtor [PR103091]
2023-05-05 17:36 [PATCH] c++: goto entering scope of obj w/ non-trivial dtor [PR103091] Patrick Palka
@ 2023-05-05 18:18 ` Jason Merrill
0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2023-05-05 18:18 UTC (permalink / raw)
To: Patrick Palka, gcc-patches
On 5/5/23 13:36, Patrick Palka wrote:
> It seems DR 2256 permitted goto to cross the initialization of a
> trivially initialized object with a non-trivial destructor. We
> already supported this as an -fpermissive extension, so this patch
> just makes us unconditionally support this.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
> for trunk?
OK.
> DR 2256
> PR c++/103091
>
> gcc/cp/ChangeLog:
>
> * decl.cc (decl_jump_unsafe): Return bool instead of int.
> Don't consider TYPE_HAS_NONTRIVIAL_DESTRUCTOR.
> (check_previous_goto_1): Simplify now that decl_jump_unsafe
> returns bool instead of int.
> (check_goto): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> * g++.old-deja/g++.other/init9.C: Don't expect diagnostics for
> goto made valid by DR 2256.
> * g++.dg/init/goto4.C: New test.
> ---
> gcc/cp/decl.cc | 56 ++++++--------------
> gcc/testsuite/g++.dg/init/goto4.C | 22 ++++++++
> gcc/testsuite/g++.old-deja/g++.other/init9.C | 7 +--
> 3 files changed, 42 insertions(+), 43 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/init/goto4.C
>
> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> index 71d33d2b7a4..23a2b2fef0b 100644
> --- a/gcc/cp/decl.cc
> +++ b/gcc/cp/decl.cc
> @@ -69,7 +69,7 @@ enum bad_spec_place {
>
> static const char *redeclaration_error_message (tree, tree);
>
> -static int decl_jump_unsafe (tree);
> +static bool decl_jump_unsafe (tree);
> static void require_complete_types_for_parms (tree);
> static tree grok_reference_init (tree, tree, tree, int);
> static tree grokvardecl (tree, tree, tree, const cp_decl_specifier_seq *,
> @@ -3548,10 +3548,9 @@ declare_local_label (tree id)
> return ent ? ent->label_decl : NULL_TREE;
> }
>
> -/* Returns nonzero if it is ill-formed to jump past the declaration of
> - DECL. Returns 2 if it's also a real problem. */
> +/* Returns true if it is ill-formed to jump past the declaration of DECL. */
>
> -static int
> +static bool
> decl_jump_unsafe (tree decl)
> {
> /* [stmt.dcl]/3: A program that jumps from a point where a local variable
> @@ -3562,18 +3561,11 @@ decl_jump_unsafe (tree decl)
> preceding types and is declared without an initializer (8.5). */
> tree type = TREE_TYPE (decl);
>
> - if (!VAR_P (decl) || TREE_STATIC (decl)
> - || type == error_mark_node)
> - return 0;
> -
> - if (DECL_NONTRIVIALLY_INITIALIZED_P (decl)
> - || variably_modified_type_p (type, NULL_TREE))
> - return 2;
> -
> - if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
> - return 1;
> -
> - return 0;
> + return (type != error_mark_node
> + && VAR_P (decl)
> + && !TREE_STATIC (decl)
> + && (DECL_NONTRIVIALLY_INITIALIZED_P (decl)
> + || variably_modified_type_p (type, NULL_TREE)));
> }
>
> /* A subroutine of check_previous_goto_1 and check_goto to identify a branch
> @@ -3625,27 +3617,18 @@ check_previous_goto_1 (tree decl, cp_binding_level* level, tree names,
> new_decls = (DECL_P (new_decls) ? DECL_CHAIN (new_decls)
> : TREE_CHAIN (new_decls)))
> {
> - int problem = decl_jump_unsafe (new_decls);
> + bool problem = decl_jump_unsafe (new_decls);
> if (! problem)
> continue;
>
> if (!identified)
> {
> - complained = identify_goto (decl, input_location, locus,
> - problem > 1
> - ? DK_ERROR : DK_PERMERROR);
> + complained = identify_goto (decl, input_location, locus, DK_ERROR);
> identified = 1;
> }
> if (complained)
> - {
> - if (problem > 1)
> - inform (DECL_SOURCE_LOCATION (new_decls),
> - " crosses initialization of %q#D", new_decls);
> - else
> - inform (DECL_SOURCE_LOCATION (new_decls),
> - " enters scope of %q#D, which has "
> - "non-trivial destructor", new_decls);
> - }
> + inform (DECL_SOURCE_LOCATION (new_decls),
> + " crosses initialization of %q#D", new_decls);
> }
>
> if (b == level)
> @@ -3790,9 +3773,9 @@ check_goto (tree decl)
>
> FOR_EACH_VEC_SAFE_ELT (ent->bad_decls, ix, bad)
> {
> - int u = decl_jump_unsafe (bad);
> + bool problem = decl_jump_unsafe (bad);
>
> - if (u > 1 && DECL_ARTIFICIAL (bad))
> + if (problem && DECL_ARTIFICIAL (bad))
> {
> /* Can't skip init of __exception_info. */
> if (identified == 1)
> @@ -3806,15 +3789,8 @@ check_goto (tree decl)
> saw_catch = true;
> }
> else if (complained)
> - {
> - if (u > 1)
> - inform (DECL_SOURCE_LOCATION (bad),
> - " skips initialization of %q#D", bad);
> - else
> - inform (DECL_SOURCE_LOCATION (bad),
> - " enters scope of %q#D which has "
> - "non-trivial destructor", bad);
> - }
> + inform (DECL_SOURCE_LOCATION (bad),
> + " skips initialization of %q#D", bad);
> }
>
> if (complained)
> diff --git a/gcc/testsuite/g++.dg/init/goto4.C b/gcc/testsuite/g++.dg/init/goto4.C
> new file mode 100644
> index 00000000000..90ae52e6455
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/init/goto4.C
> @@ -0,0 +1,22 @@
> +// DR 2256
> +// PR c++/103091
> +// { dg-do run }
> +
> +static int i;
> +
> +struct A {
> + ~A() { ++i;}
> +};
> +
> +void f() {
> + goto L;
> + A a;
> +L:
> + return;
> +}
> +
> +int main() {
> + f();
> + if (i != 1)
> + __builtin_abort();
> +}
> diff --git a/gcc/testsuite/g++.old-deja/g++.other/init9.C b/gcc/testsuite/g++.old-deja/g++.other/init9.C
> index 46d99028bdd..0194cd1b49a 100644
> --- a/gcc/testsuite/g++.old-deja/g++.other/init9.C
> +++ b/gcc/testsuite/g++.old-deja/g++.other/init9.C
> @@ -24,9 +24,10 @@ struct X {
> };
>
> void b() {
> - goto bar; // { dg-message "" } jump from here
> - X x; // { dg-message "" } jump crosses initialization
> - bar: // { dg-error "" } jump to here
> + // This was ill-formed until DR 2256.
> + goto bar;
> + X x;
> + bar:
> ;
> }
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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