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Re: [PATCH] adding missing LTO to some warning options (PR 78606)
- From: Tom de Vries <Tom_deVries at mentor dot com>
- To: Martin Sebor <msebor at gmail dot com>, Gcc Patch List <gcc-patches at gcc dot gnu dot org>, Richard Biener <rguenther at suse dot de>
- Date: Tue, 2 May 2017 12:17:40 +0200
- Subject: Re: [PATCH] adding missing LTO to some warning options (PR 78606)
- Authentication-results: sourceware.org; auth=none
- References: <06c24069-90af-5778-52a2-c9167eb109ab@gmail.com> <568de1cb-21ed-26ea-8a80-f177f189f293@mentor.com> <8b597659-d03e-840d-271e-65fa77415090@gmail.com>
On 05/01/2017 08:05 PM, Martin Sebor wrote:
On 04/30/2017 02:02 PM, Tom de Vries wrote:
On 01/10/2017 11:16 PM, Martin Sebor wrote:
+ __builtin_sprintf (d, "%32s", "x"); /* { dg-warning "directive
writing 32 bytes into a region of size 12" "-Wformat-length" { xfail
*-*-* } } */
This xpasses for me on an older system:
...
XPASS: gcc.dg/pr78768.c -Wformat-overflow (test for warnings, line 11)
...
The mechanism is as follows:
- the system doesn't have linker plugin support, and sets
HAVE_LTO_PLUGIN to 0
- consequently, opts.c:finish_options() sets x_flag_fat_lto_objects to 1
in cc1
- cgraphunit.c:symbol_table::compile() does not return
here:
...
/* Do nothing else if any IPA pass found errors or if we are just
streaming LTO. */
if (seen_error ()
|| (!in_lto_p && flag_lto && !flag_fat_lto_objects))
{
timevar_pop (TV_CGRAPHOPT);
return;
}
...
and ends up calling expand_all_functions, which calls
pass_sprintf_length
- the warning is generated by cc1
Maybe the test needs:
...
/* { dg-require-linker-plugin "" } */
...
?
That seems possible. IIUC, without linker plugin support the
pass will run when the ordinary object file is created during
the first stage of compilation. I don't have a system to confirm
it on but if pr78768.c xfails when you add the directive I'd say
go ahead and commit the fix as obvious.
Done.
Thanks,
- Tom
Require linker plugin for pr78768.c
The test-case has an xfail-ed line. For linkers without plugin support, that
line happens to xpass. Require linker with plugin support, such that the line
is no longer xpass-ing, but unsupported.
2017-05-01 Tom de Vries <tom@codesourcery.com>
* gcc.dg/pr78768.c: Require linker plugin.
---
gcc/testsuite/ChangeLog | 4 ++++
gcc/testsuite/gcc.dg/pr78768.c | 1 +
2 files changed, 5 insertions(+)
diff --git a/gcc/testsuite/gcc.dg/pr78768.c b/gcc/testsuite/gcc.dg/pr78768.c
index 68d717a..b6cda47 100644
--- a/gcc/testsuite/gcc.dg/pr78768.c
+++ b/gcc/testsuite/gcc.dg/pr78768.c
@@ -2,6 +2,7 @@
by -flto
{ dg-do link }
{ dg-require-effective-target lto }
+ { dg-require-linker-plugin "" }
{ dg-options "-O2 -Walloca-larger-than=10 -Wformat -Wformat-overflow -flto" } */
int main (void)