* Dangling pointer in ICF from c_str method.
@ 2011-02-02 21:20 Sriraman Tallam
2011-02-02 21:48 ` Ian Lance Taylor
2011-02-03 9:41 ` Richard Guenther
0 siblings, 2 replies; 5+ messages in thread
From: Sriraman Tallam @ 2011-02-02 21:20 UTC (permalink / raw)
To: binutils, Doug Kwan (關振德),
Ian Lance Taylor, rguenth
[-- Attachment #1: Type: text/plain, Size: 683 bytes --]
Hi,
Doug Kwan found a bug in ICF caused by a dangling pointer from
using c_str on a temporary string object. I have attached a patch to
fix it. I suspect this as the cause of bug reported in :
http://sourceware.org/bugzilla/show_bug.cgi?id=12388. Richard, could
you please see if this patch fixes the bug as I am unable to reproduce
it.
2011-02-02 Sriraman Tallam <tmsriram@google.com>
* icf.h (is_section_foldable_candidate): Change type of parameter
to std::string.
* icf.cc (Icf::find_identical_sections): Change type of local variable
section_name to be std::string.
(is_function_ctor_or_dtor): Change type of parameter to std::string.
Thanks,
-Sri.
[-- Attachment #2: gold_patch.txt --]
[-- Type: text/plain, Size: 3380 bytes --]
Index: icf.cc
===================================================================
RCS file: /cvs/src/src/gold/icf.cc,v
retrieving revision 1.18
diff -u -u -p -r1.18 icf.cc
--- icf.cc 25 Jan 2011 17:14:59 -0000 1.18
+++ icf.cc 2 Feb 2011 19:58:33 -0000
@@ -652,16 +652,17 @@ match_sections(unsigned int iteration_nu
}
// During safe icf (--icf=safe), only fold functions that are ctors or dtors.
-// This function returns true if the mangled function name is a ctor or a
-// dtor.
+// This function returns true if the section name is that of a ctor or a dtor.
static bool
-is_function_ctor_or_dtor(const char* mangled_func_name)
+is_function_ctor_or_dtor(const std::string& section_name)
{
- if ((is_prefix_of("_ZN", mangled_func_name)
- || is_prefix_of("_ZZ", mangled_func_name))
- && (is_gnu_v3_mangled_ctor(mangled_func_name)
- || is_gnu_v3_mangled_dtor(mangled_func_name)))
+ const char* mangled_func_name = strrchr(section_name.c_str(), '.');
+ gold_assert (mangled_func_name != NULL);
+ if ((is_prefix_of("._ZN", mangled_func_name)
+ || is_prefix_of("._ZZ", mangled_func_name))
+ && (is_gnu_v3_mangled_ctor(mangled_func_name + 1)
+ || is_gnu_v3_mangled_dtor(mangled_func_name + 1)))
{
return true;
}
@@ -696,7 +697,7 @@ Icf::find_identical_sections(const Input
for (unsigned int i = 0;i < (*p)->shnum(); ++i)
{
- const char* section_name = (*p)->section_name(i).c_str();
+ const std::string& section_name = (*p)->section_name(i);
if (!is_section_foldable_candidate(section_name))
continue;
if (!(*p)->is_section_included(i))
@@ -704,13 +705,11 @@ Icf::find_identical_sections(const Input
if (parameters->options().gc_sections()
&& symtab->gc()->is_section_garbage(*p, i))
continue;
- const char* mangled_func_name = strrchr(section_name, '.');
- gold_assert(mangled_func_name != NULL);
// With --icf=safe, check if the mangled function name is a ctor
// or a dtor. The mangled function name can be obtained from the
// section name by stripping the section prefix.
if (parameters->options().icf_safe_folding()
- && !is_function_ctor_or_dtor(mangled_func_name + 1)
+ && !is_function_ctor_or_dtor(section_name)
&& (!target.can_check_for_function_pointers()
|| section_has_function_pointers(*p, i)))
{
Index: icf.h
===================================================================
RCS file: /cvs/src/src/gold/icf.h,v
retrieving revision 1.10
diff -u -u -p -r1.10 icf.h
--- icf.h 25 Aug 2010 08:36:54 -0000 1.10
+++ icf.h 2 Feb 2011 19:58:33 -0000
@@ -168,10 +168,11 @@ class Icf
// earlier gcc versions, like 4.0.3, put constructors and destructors in
// .gnu.linkonce.t sections and hence should be included too.
inline bool
-is_section_foldable_candidate(const char* section_name)
+is_section_foldable_candidate(const std::string& section_name)
{
- return (is_prefix_of(".text", section_name)
- || is_prefix_of(".gnu.linkonce.t", section_name));
+ const char* section_name_cstr = section_name.c_str();
+ return (is_prefix_of(".text", section_name_cstr)
+ || is_prefix_of(".gnu.linkonce.t", section_name_cstr));
}
} // End of namespace gold.
cvs diff: Diffing po
cvs diff: Diffing testsuite
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Dangling pointer in ICF from c_str method.
2011-02-02 21:20 Dangling pointer in ICF from c_str method Sriraman Tallam
@ 2011-02-02 21:48 ` Ian Lance Taylor
2011-02-02 21:57 ` Sriraman Tallam
2011-02-03 9:41 ` Richard Guenther
1 sibling, 1 reply; 5+ messages in thread
From: Ian Lance Taylor @ 2011-02-02 21:48 UTC (permalink / raw)
To: Sriraman Tallam; +Cc: binutils, Doug Kwan (關振德), rguenth
Sriraman Tallam <tmsriram@google.com> writes:
> 2011-02-02 Sriraman Tallam <tmsriram@google.com>
>
> * icf.h (is_section_foldable_candidate): Change type of parameter
> to std::string.
> * icf.cc (Icf::find_identical_sections): Change type of local variable
> section_name to be std::string.
> (is_function_ctor_or_dtor): Change type of parameter to std::string.
> static bool
> -is_function_ctor_or_dtor(const char* mangled_func_name)
> +is_function_ctor_or_dtor(const std::string& section_name)
> {
> - if ((is_prefix_of("_ZN", mangled_func_name)
> - || is_prefix_of("_ZZ", mangled_func_name))
> - && (is_gnu_v3_mangled_ctor(mangled_func_name)
> - || is_gnu_v3_mangled_dtor(mangled_func_name)))
> + const char* mangled_func_name = strrchr(section_name.c_str(), '.');
> + gold_assert (mangled_func_name != NULL);
No space before parenthesis.
> @@ -696,7 +697,7 @@ Icf::find_identical_sections(const Input
>
> for (unsigned int i = 0;i < (*p)->shnum(); ++i)
> {
> - const char* section_name = (*p)->section_name(i).c_str();
> + const std::string& section_name = (*p)->section_name(i);
Make this a normal variable rather than a reference. That is, drop the
'&'. I think your code is correct but there is no need for a reference
here; RVO should apply, I think.
This is OK with those changes.
Thanks.
Ian
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Dangling pointer in ICF from c_str method.
2011-02-02 21:48 ` Ian Lance Taylor
@ 2011-02-02 21:57 ` Sriraman Tallam
0 siblings, 0 replies; 5+ messages in thread
From: Sriraman Tallam @ 2011-02-02 21:57 UTC (permalink / raw)
To: Ian Lance Taylor; +Cc: binutils, Doug Kwan (關振德), rguenth
[-- Attachment #1: Type: text/plain, Size: 1629 bytes --]
Made the changes and committed the patch.
Thanks,
-Sri.
On Wed, Feb 2, 2011 at 1:48 PM, Ian Lance Taylor <iant@google.com> wrote:
> Sriraman Tallam <tmsriram@google.com> writes:
>
>> 2011-02-02 Sriraman Tallam <tmsriram@google.com>
>>
>> * icf.h (is_section_foldable_candidate): Change type of parameter
>> to std::string.
>> * icf.cc (Icf::find_identical_sections): Change type of local variable
>> section_name to be std::string.
>> (is_function_ctor_or_dtor): Change type of parameter to std::string.
>
>> static bool
>> -is_function_ctor_or_dtor(const char* mangled_func_name)
>> +is_function_ctor_or_dtor(const std::string& section_name)
>> {
>> - if ((is_prefix_of("_ZN", mangled_func_name)
>> - || is_prefix_of("_ZZ", mangled_func_name))
>> - && (is_gnu_v3_mangled_ctor(mangled_func_name)
>> - || is_gnu_v3_mangled_dtor(mangled_func_name)))
>> + const char* mangled_func_name = strrchr(section_name.c_str(), '.');
>> + gold_assert (mangled_func_name != NULL);
>
> No space before parenthesis.
>
>> @@ -696,7 +697,7 @@ Icf::find_identical_sections(const Input
>>
>> for (unsigned int i = 0;i < (*p)->shnum(); ++i)
>> {
>> - const char* section_name = (*p)->section_name(i).c_str();
>> + const std::string& section_name = (*p)->section_name(i);
>
> Make this a normal variable rather than a reference. That is, drop the
> '&'. I think your code is correct but there is no need for a reference
> here; RVO should apply, I think.
>
> This is OK with those changes.
>
> Thanks.
>
> Ian
>
[-- Attachment #2: gold_patch.txt --]
[-- Type: text/plain, Size: 3378 bytes --]
Index: icf.cc
===================================================================
RCS file: /cvs/src/src/gold/icf.cc,v
retrieving revision 1.18
diff -u -u -p -r1.18 icf.cc
--- icf.cc 25 Jan 2011 17:14:59 -0000 1.18
+++ icf.cc 2 Feb 2011 21:53:56 -0000
@@ -652,16 +652,17 @@ match_sections(unsigned int iteration_nu
}
// During safe icf (--icf=safe), only fold functions that are ctors or dtors.
-// This function returns true if the mangled function name is a ctor or a
-// dtor.
+// This function returns true if the section name is that of a ctor or a dtor.
static bool
-is_function_ctor_or_dtor(const char* mangled_func_name)
+is_function_ctor_or_dtor(const std::string& section_name)
{
- if ((is_prefix_of("_ZN", mangled_func_name)
- || is_prefix_of("_ZZ", mangled_func_name))
- && (is_gnu_v3_mangled_ctor(mangled_func_name)
- || is_gnu_v3_mangled_dtor(mangled_func_name)))
+ const char* mangled_func_name = strrchr(section_name.c_str(), '.');
+ gold_assert(mangled_func_name != NULL);
+ if ((is_prefix_of("._ZN", mangled_func_name)
+ || is_prefix_of("._ZZ", mangled_func_name))
+ && (is_gnu_v3_mangled_ctor(mangled_func_name + 1)
+ || is_gnu_v3_mangled_dtor(mangled_func_name + 1)))
{
return true;
}
@@ -696,7 +697,7 @@ Icf::find_identical_sections(const Input
for (unsigned int i = 0;i < (*p)->shnum(); ++i)
{
- const char* section_name = (*p)->section_name(i).c_str();
+ const std::string section_name = (*p)->section_name(i);
if (!is_section_foldable_candidate(section_name))
continue;
if (!(*p)->is_section_included(i))
@@ -704,13 +705,11 @@ Icf::find_identical_sections(const Input
if (parameters->options().gc_sections()
&& symtab->gc()->is_section_garbage(*p, i))
continue;
- const char* mangled_func_name = strrchr(section_name, '.');
- gold_assert(mangled_func_name != NULL);
// With --icf=safe, check if the mangled function name is a ctor
// or a dtor. The mangled function name can be obtained from the
// section name by stripping the section prefix.
if (parameters->options().icf_safe_folding()
- && !is_function_ctor_or_dtor(mangled_func_name + 1)
+ && !is_function_ctor_or_dtor(section_name)
&& (!target.can_check_for_function_pointers()
|| section_has_function_pointers(*p, i)))
{
Index: icf.h
===================================================================
RCS file: /cvs/src/src/gold/icf.h,v
retrieving revision 1.10
diff -u -u -p -r1.10 icf.h
--- icf.h 25 Aug 2010 08:36:54 -0000 1.10
+++ icf.h 2 Feb 2011 21:53:56 -0000
@@ -168,10 +168,11 @@ class Icf
// earlier gcc versions, like 4.0.3, put constructors and destructors in
// .gnu.linkonce.t sections and hence should be included too.
inline bool
-is_section_foldable_candidate(const char* section_name)
+is_section_foldable_candidate(const std::string& section_name)
{
- return (is_prefix_of(".text", section_name)
- || is_prefix_of(".gnu.linkonce.t", section_name));
+ const char* section_name_cstr = section_name.c_str();
+ return (is_prefix_of(".text", section_name_cstr)
+ || is_prefix_of(".gnu.linkonce.t", section_name_cstr));
}
} // End of namespace gold.
cvs diff: Diffing po
cvs diff: Diffing testsuite
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Dangling pointer in ICF from c_str method.
2011-02-02 21:20 Dangling pointer in ICF from c_str method Sriraman Tallam
2011-02-02 21:48 ` Ian Lance Taylor
@ 2011-02-03 9:41 ` Richard Guenther
2011-02-03 20:42 ` Ian Lance Taylor
1 sibling, 1 reply; 5+ messages in thread
From: Richard Guenther @ 2011-02-03 9:41 UTC (permalink / raw)
To: Sriraman Tallam
Cc: binutils, Doug Kwan (�P振德), Ian Lance Taylor
On Wed, 2 Feb 2011, Sriraman Tallam wrote:
> Hi,
>
> Doug Kwan found a bug in ICF caused by a dangling pointer from
> using c_str on a temporary string object. I have attached a patch to
> fix it. I suspect this as the cause of bug reported in :
> http://sourceware.org/bugzilla/show_bug.cgi?id=12388. Richard, could
> you please see if this patch fixes the bug as I am unable to reproduce
> it.
It doesn't apply to the 2.21 release for me. I'll pick it up when
2.21.1 is released.
Richard.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: Dangling pointer in ICF from c_str method.
2011-02-03 9:41 ` Richard Guenther
@ 2011-02-03 20:42 ` Ian Lance Taylor
0 siblings, 0 replies; 5+ messages in thread
From: Ian Lance Taylor @ 2011-02-03 20:42 UTC (permalink / raw)
To: Richard Guenther
Cc: Sriraman Tallam, binutils, Doug Kwan (關振德)
Richard Guenther <rguenther@suse.de> writes:
> On Wed, 2 Feb 2011, Sriraman Tallam wrote:
>
>> Hi,
>>
>> Doug Kwan found a bug in ICF caused by a dangling pointer from
>> using c_str on a temporary string object. I have attached a patch to
>> fix it. I suspect this as the cause of bug reported in :
>> http://sourceware.org/bugzilla/show_bug.cgi?id=12388. Richard, could
>> you please see if this patch fixes the bug as I am unable to reproduce
>> it.
>
> It doesn't apply to the 2.21 release for me. I'll pick it up when
> 2.21.1 is released.
I applied Sri's patch to binutils 2.21 branch.
Ian
^ permalink raw reply [flat|nested] 5+ messages in thread
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2011-02-02 21:20 Dangling pointer in ICF from c_str method Sriraman Tallam
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2011-02-03 9:41 ` Richard Guenther
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