On Fri, Oct 11, 2019 at 04:14:16PM -0400, Jason Merrill wrote:
> > On x86_64 and most other targets, cleanup here (if non-NULL) is the
> > CALL_EXPR, as destructor return type is void, but on arm, as the dtor return
> > type is some pointer, the CALL_EXPR is wrapped into a NOP_EXPR to void.
> > protected_set_expr_location then on x86_64 clears the CALL_EXPR location,
> > but on arm only NOP_EXPR location.
> >
> > The following patch (totally untested) should fix that.
> >
> > For the warning location, perhaps we could special case destructor calls
> > in push_cx_call_context (to offset the intentional clearing of location for
> > debugging purposes), if they don't have location set, don't use
> > input_location for them, but try to pick DECL_SOURCE_LOCATION for the
> > variable being destructed?
>
> Expanding the CLEANUP_EXPR of a CLEANUP_STMT could use the EXPR_LOCATION of
> the CLEANUP_STMT. Or the EXPR_LOCATION of *jump_target, if suitable.
The already previously posted patch (now attached as first) has now been
bootstrapped/regtested on x86_64-linux and i686-linux, and regardless if we
improve the location or not should fix the arm vs. the rest of the world
difference. Is that ok for trunk?
As for CLEANUP_STMT, I've tried it (the second patch), but it didn't change
anything, the diagnostics was still
constexpr-dtor3.C:16:23: in ‘constexpr’ expansion of ‘f4()’
constexpr-dtor3.C:16:24: in ‘constexpr’ expansion of ‘(& w13)->W7::~W7()’
constexpr-dtor3.C:5:34: error: inline assembly is not a constant expression
5 | constexpr ~W7 () { if (w == 5) asm (""); w = 3; } // { dg-error
"inline assembly is not a constant expression" }
| ^~~
constexpr-dtor3.C:5:34: note: only unevaluated inline assembly is allowed in a
‘constexpr’ function in C++2a
as without that change.
I've also tried the third patch, tested so far with check-c++-all, which
changes that to
constexpr-dtor3.C:16:23: in ‘constexpr’ expansion of ‘f4()’
constexpr-dtor3.C:12:6: in ‘constexpr’ expansion of ‘(& w13)->W7::~W7()’
constexpr-dtor3.C:5:34: error: inline assembly is not a constant expression
5 | constexpr ~W7 () { if (w == 5) asm (""); w = 3; } // { dg-error
"inline assembly is not a constant expression" }
| ^~~
constexpr-dtor3.C:5:34: note: only unevaluated inline assembly is allowed in a
‘constexpr’ function in C++2a
Jakub
2019-10-16 Jakub Jelinek <ja...@redhat.com>
* decl.c (cxx_maybe_build_cleanup): When clearing location of cleanup,
if cleanup is a nop, clear location of its operand too.
--- gcc/cp/decl.c.jj 2019-10-10 01:33:38.154943945 +0200
+++ gcc/cp/decl.c 2019-10-11 10:09:24.321277942 +0200
@@ -16864,6 +16864,8 @@ cxx_maybe_build_cleanup (tree decl, tsub
the end of the block. So let's unset the location of the
destructor call instead. */
protected_set_expr_location (cleanup, UNKNOWN_LOCATION);
+ if (cleanup && CONVERT_EXPR_P (cleanup))
+ protected_set_expr_location (TREE_OPERAND (cleanup, 0), UNKNOWN_LOCATION);
if (cleanup
&& DECL_P (decl)
2019-10-16 Jakub Jelinek <ja...@redhat.com>
* constexpr.c (cxx_eval_constant_expression) <case CLEANUP_STMT>:
Temporarily change input_location to CLEANUP_STMT location.
--- gcc/cp/constexpr.c.jj 2019-10-10 01:33:38.185943480 +0200
+++ gcc/cp/constexpr.c 2019-10-11 22:54:32.628051700 +0200
@@ -4980,9 +4980,13 @@ cxx_eval_constant_expression (const cons
case CLEANUP_STMT:
{
tree initial_jump_target = jump_target ? *jump_target : NULL_TREE;
+ location_t loc = input_location;
+ if (EXPR_HAS_LOCATION (t))
+ input_location = EXPR_LOCATION (t);
r = cxx_eval_constant_expression (ctx, CLEANUP_BODY (t), lval,
non_constant_p, overflow_p,
jump_target);
+ input_location = loc;
if (!CLEANUP_EH_ONLY (t) && !*non_constant_p)
/* Also evaluate the cleanup. If we weren't skipping at the
start of the CLEANUP_BODY, change jump_target temporarily
2019-10-16 Jakub Jelinek <ja...@redhat.com>
* decl.c (cxx_maybe_build_cleanup): When clearing location of cleanup,
if cleanup is a nop, clear location of its operand too.
* constexpr.c (push_cx_call_context): For calls to destructors, use
DECL_SOURCE_LOCATION of destructed variable in preference to
input_location.
* g++.dg/cpp2a/constexpr-dtor3.C: Expect in 'constexpr' expansion of
message on the line with variable declaration.
--- gcc/cp/decl.c.jj 2019-10-16 09:30:57.490109872 +0200
+++ gcc/cp/decl.c 2019-10-16 17:45:48.647529567 +0200
@@ -16864,6 +16864,8 @@ cxx_maybe_build_cleanup (tree decl, tsub
the end of the block. So let's unset the location of the
destructor call instead. */
protected_set_expr_location (cleanup, UNKNOWN_LOCATION);
+ if (cleanup && CONVERT_EXPR_P (cleanup))
+ protected_set_expr_location (TREE_OPERAND (cleanup, 0), UNKNOWN_LOCATION);
if (cleanup
&& DECL_P (decl)
--- gcc/cp/constexpr.c.jj 2019-10-16 17:35:37.848752468 +0200
+++ gcc/cp/constexpr.c 2019-10-16 18:07:42.472688066 +0200
@@ -1457,7 +1457,26 @@ push_cx_call_context (tree call)
{
++call_stack_tick;
if (!EXPR_HAS_LOCATION (call))
- SET_EXPR_LOCATION (call, input_location);
+ {
+ tree fun = get_function_named_in_call (call);
+ location_t loc = input_location;
+ /* Calls to destructors have UNKNOWN_LOCATION, in order to avoid
+ problems debugging at the end of scopes. For diagnostic purposes,
+ try to use location of the variable that needs destruction. */
+ if (fun && DECL_DESTRUCTOR_P (fun))
+ {
+ tree arg = CALL_EXPR_ARG (call, 0);
+ STRIP_NOPS (arg);
+ if (TREE_CODE (arg) == ADDR_EXPR)
+ {
+ tree var = get_base_address (TREE_OPERAND (arg, 0));
+ if (DECL_P (var)
+ && DECL_SOURCE_LOCATION (var) != UNKNOWN_LOCATION)
+ loc = DECL_SOURCE_LOCATION (var);
+ }
+ }
+ SET_EXPR_LOCATION (call, loc);
+ }
call_stack.safe_push (call);
int len = call_stack.length ();
if (len > max_constexpr_depth)
--- gcc/testsuite/g++.dg/cpp2a/constexpr-dtor3.C.jj 2019-10-05
09:36:39.250674497 +0200
+++ gcc/testsuite/g++.dg/cpp2a/constexpr-dtor3.C 2019-10-16
18:10:48.603877004 +0200
@@ -149,7 +149,7 @@ constexpr int x3 = f3 ();
constexpr int
f4 ()
{
- W7 w13 = 5;
+ W7 w13 = 5; // { dg-message "in 'constexpr' expansion of" }
return 0;
}
