* [PATCH] tree-optimization/108449 - keep maybe_special_function_p behavior
@ 2023-01-19 9:46 Richard Biener
2023-01-21 21:24 ` Jan Hubicka
0 siblings, 1 reply; 3+ messages in thread
From: Richard Biener @ 2023-01-19 9:46 UTC (permalink / raw)
To: gcc-patches; +Cc: Jan Hubicka, Jakub Jelinek
When we have a static declaration without definition we diagnose
that and turn it into an extern declaration. That can alter
the outcome of maybe_special_function_p here and there's really
no point in doing that, so don't.
Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?
Thanks,
Richard.
PR tree-optimization/108449
* cgraphunit.cc (check_global_declaration): Do not turn
undefined statics into externs.
* gcc.dg/pr108449.c: New testcase.
---
gcc/cgraphunit.cc | 2 --
gcc/testsuite/gcc.dg/pr108449.c | 5 +++++
2 files changed, 5 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr108449.c
diff --git a/gcc/cgraphunit.cc b/gcc/cgraphunit.cc
index 59ce2708b7b..832818d651f 100644
--- a/gcc/cgraphunit.cc
+++ b/gcc/cgraphunit.cc
@@ -1087,8 +1087,6 @@ check_global_declaration (symtab_node *snode)
else
warning (OPT_Wunused_function, "%q+F declared %<static%> but never "
"defined", decl);
- /* This symbol is effectively an "extern" declaration now. */
- TREE_PUBLIC (decl) = 1;
}
/* Warn about static fns or vars defined but not used. */
diff --git a/gcc/testsuite/gcc.dg/pr108449.c b/gcc/testsuite/gcc.dg/pr108449.c
new file mode 100644
index 00000000000..4a3ae5b3ed4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr108449.c
@@ -0,0 +1,5 @@
+/* { dg-do compile } */
+/* { dg-options "-O" } */
+
+static int vfork(); /* { dg-warning "used but never defined" } */
+void f() { vfork(); }
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tree-optimization/108449 - keep maybe_special_function_p behavior
2023-01-19 9:46 [PATCH] tree-optimization/108449 - keep maybe_special_function_p behavior Richard Biener
@ 2023-01-21 21:24 ` Jan Hubicka
2023-01-23 7:29 ` Richard Biener
0 siblings, 1 reply; 3+ messages in thread
From: Jan Hubicka @ 2023-01-21 21:24 UTC (permalink / raw)
To: Richard Biener; +Cc: gcc-patches, Jakub Jelinek
> When we have a static declaration without definition we diagnose
> that and turn it into an extern declaration. That can alter
> the outcome of maybe_special_function_p here and there's really
> no point in doing that, so don't.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?
>
> Thanks,
> Richard.
>
> PR tree-optimization/108449
> * cgraphunit.cc (check_global_declaration): Do not turn
> undefined statics into externs.
Looks OK to me. I got kind of suprrised we still have
maybe_special_function_p and we do chane of public flag.
I wonder if we can run into similar problem when promoting declaration
at LTO time?
Honza
>
> * gcc.dg/pr108449.c: New testcase.
> ---
> gcc/cgraphunit.cc | 2 --
> gcc/testsuite/gcc.dg/pr108449.c | 5 +++++
> 2 files changed, 5 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/pr108449.c
>
> diff --git a/gcc/cgraphunit.cc b/gcc/cgraphunit.cc
> index 59ce2708b7b..832818d651f 100644
> --- a/gcc/cgraphunit.cc
> +++ b/gcc/cgraphunit.cc
> @@ -1087,8 +1087,6 @@ check_global_declaration (symtab_node *snode)
> else
> warning (OPT_Wunused_function, "%q+F declared %<static%> but never "
> "defined", decl);
> - /* This symbol is effectively an "extern" declaration now. */
> - TREE_PUBLIC (decl) = 1;
> }
>
> /* Warn about static fns or vars defined but not used. */
> diff --git a/gcc/testsuite/gcc.dg/pr108449.c b/gcc/testsuite/gcc.dg/pr108449.c
> new file mode 100644
> index 00000000000..4a3ae5b3ed4
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr108449.c
> @@ -0,0 +1,5 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O" } */
> +
> +static int vfork(); /* { dg-warning "used but never defined" } */
> +void f() { vfork(); }
> --
> 2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tree-optimization/108449 - keep maybe_special_function_p behavior
2023-01-21 21:24 ` Jan Hubicka
@ 2023-01-23 7:29 ` Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2023-01-23 7:29 UTC (permalink / raw)
To: Jan Hubicka; +Cc: gcc-patches, Jakub Jelinek
On Sat, 21 Jan 2023, Jan Hubicka wrote:
> > When we have a static declaration without definition we diagnose
> > that and turn it into an extern declaration. That can alter
> > the outcome of maybe_special_function_p here and there's really
> > no point in doing that, so don't.
> >
> > Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?
> >
> > Thanks,
> > Richard.
> >
> > PR tree-optimization/108449
> > * cgraphunit.cc (check_global_declaration): Do not turn
> > undefined statics into externs.
> Looks OK to me. I got kind of suprrised we still have
> maybe_special_function_p and we do chane of public flag.
Yeah, well ...
> I wonder if we can run into similar problem when promoting declaration
> at LTO time?
Possibly - I guess we could amend maybe_special_function_p to check
if there's a visible definition. Or somehow get rid of this thing
and apply the special-function 'name' thing as explicit attributes
during parsing instead ...
Richard.
> Honza
> >
> > * gcc.dg/pr108449.c: New testcase.
> > ---
> > gcc/cgraphunit.cc | 2 --
> > gcc/testsuite/gcc.dg/pr108449.c | 5 +++++
> > 2 files changed, 5 insertions(+), 2 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.dg/pr108449.c
> >
> > diff --git a/gcc/cgraphunit.cc b/gcc/cgraphunit.cc
> > index 59ce2708b7b..832818d651f 100644
> > --- a/gcc/cgraphunit.cc
> > +++ b/gcc/cgraphunit.cc
> > @@ -1087,8 +1087,6 @@ check_global_declaration (symtab_node *snode)
> > else
> > warning (OPT_Wunused_function, "%q+F declared %<static%> but never "
> > "defined", decl);
> > - /* This symbol is effectively an "extern" declaration now. */
> > - TREE_PUBLIC (decl) = 1;
> > }
> >
> > /* Warn about static fns or vars defined but not used. */
> > diff --git a/gcc/testsuite/gcc.dg/pr108449.c b/gcc/testsuite/gcc.dg/pr108449.c
> > new file mode 100644
> > index 00000000000..4a3ae5b3ed4
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/pr108449.c
> > @@ -0,0 +1,5 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O" } */
> > +
> > +static int vfork(); /* { dg-warning "used but never defined" } */
> > +void f() { vfork(); }
> > --
> > 2.35.3
>
--
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
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2023-01-19 9:46 [PATCH] tree-optimization/108449 - keep maybe_special_function_p behavior Richard Biener
2023-01-21 21:24 ` Jan Hubicka
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