[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #15 from Jason Merrill jason at gcc dot gnu.org --- Author: jason Date: Tue Sep 9 11:57:25 2014 New Revision: 215061 URL: https://gcc.gnu.org/viewcvs?rev=215061root=gccview=rev Log: PR c++/61214 PR c++/62224 gcc/ * gimple-fold.c (can_refer_decl_in_current_unit_p): Don't allow reference to a DECL_EXTERNAL COMDAT. gcc/cp/ * decl2.c (decl_needed_p): Revert virtual functions change. Added: branches/gcc-4_9-branch/gcc/testsuite/g++.dg/ipa/devirt-40.C Modified: branches/gcc-4_9-branch/gcc/ChangeLog branches/gcc-4_9-branch/gcc/cp/ChangeLog branches/gcc-4_9-branch/gcc/cp/decl2.c branches/gcc-4_9-branch/gcc/gimple-fold.c branches/gcc-4_9-branch/gcc/testsuite/g++.dg/ipa/devirt-39.C
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 Markus Trippelsdorf trippels at gcc dot gnu.org changed: What|Removed |Added Resolution|INVALID |FIXED --- Comment #16 from Markus Trippelsdorf trippels at gcc dot gnu.org --- Changing resolution. Fixed.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #17 from Chris Clayton chris2553 at googlemail dot com --- I can confirm that with Jason's code changes (referenced in comment 15) to gcc/cp/decl2.c and gcc/gimple-fold.c, the resultant compiler successfully builds qt-creator-3.2.0. Thanks Jason.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224
Markus Trippelsdorf trippels at gcc dot gnu.org changed:
What|Removed |Added
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #11 from Markus Trippelsdorf trippels at gcc dot gnu.org ---
Here's a small testcase:
markus@x4 tmp % cat cppcodemodelinspectordialog.ii
namespace CppTools
{
class A
{
public:
virtual void headerPaths () = 0;
};
namespace Internal
{
class CppModelManager : CppTools::A
{
void
headerPaths ()
{
ensureUpdated ();
}
void ensureUpdated ();
};
}
}
CppTools::A *a;
void
fn1 ()
{
a-headerPaths ();
}
(before r214208)
markus@x4 tmp % g++ -Wl,--no-undefined -shared -fPIC -O2
cppcodemodelinspectordialog.ii
markus@x4 tmp %
(after r214208)
markus@x4 tmp % g++ -Wl,--no-undefined -shared -fPIC -O2
cppcodemodelinspectordialog.ii
/tmp/ccMZQE0g.o:cppcodemodelinspectordialog.ii:function fn1(): error: undefined
reference to 'CppTools::Internal::CppModelManager::ensureUpdated()'
/tmp/ccMZQE0g.o:cppcodemodelinspectordialog.ii:function
CppTools::Internal::CppModelManager::headerPaths(): error: undefined reference
to 'CppTools::Internal::CppModelManager::ensureUpdated()'
collect2: error: ld returned 1 exit status
(one can use -fno-devirtualize-speculatively as a workaround)
markus@x4 tmp % g++ -Wl,--no-undefined -fno-devirtualize-speculatively -shared
-fPIC -O2 cppcodemodelinspectordialog.ii
markus@x4 tmp %
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #12 from Chris Clayton chris2553 at googlemail dot com --- Sorry, you'll have to stick with me here while a figure out what that means. I think you are saying that prior to r214208, the symbols definedMacros() and headerPaths() were present but effectively no-ops. Post r214208 they now contain operations including calls to ensureUpdated(). Given that the symbol for ensureUpdated() appears to be present in libCppTools.so (along with the symbols for its two post-r214208 callers), does that suggest a problem with the linker, which is /usr/bin/ld from the latest version (2.24) of binutils? Or could it be anything to do with my system being a 32bit userspace on a 64bit kernel? I usually build packages as rpms and have the rpm binary wrapped in a script which uses prefixes the call to the actual rpm binary with setarch i386. I've been careful whilst investigated this problem to make sure that I prefix calls to qmake and make with setarch i386. I've built loads and loads of packages with this setup (including gcc). I'm just trying to figure out the next port of call with this problem. I note that the Debian folks have a bug logged but seem to be waiting on resolution via this bug report - https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=759862.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #13 from Markus Trippelsdorf trippels at gcc dot gnu.org --- (In reply to Chris Clayton from comment #12) Sorry, you'll have to stick with me here while a figure out what that means. I think you are saying that prior to r214208, the symbols definedMacros() and headerPaths() were present but effectively no-ops. Post r214208 they now contain operations including calls to ensureUpdated(). Given that the symbol for ensureUpdated() appears to be present in libCppTools.so (along with the symbols for its two post-r214208 callers), does that suggest a problem with the linker, which is /usr/bin/ld from the latest version (2.24) of binutils? No. This has nothing to do with libCppTools.so. As I wrote before the build system of qt-creator must be changed to provide the missing symbol by simply adding cppmodelmanager.o to the libCppEditor.so link command.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224
--- Comment #14 from Markus Trippelsdorf trippels at gcc dot gnu.org ---
(In reply to Markus Trippelsdorf from comment #13)
(In reply to Chris Clayton from comment #12)
Sorry, you'll have to stick with me here while a figure out what that means.
I think you are saying that prior to r214208, the symbols definedMacros()
and headerPaths() were present but effectively no-ops. Post r214208 they now
contain operations including calls to ensureUpdated().
Given that the symbol for ensureUpdated() appears to be present in
libCppTools.so (along with the symbols for its two post-r214208 callers),
does that suggest a problem with the linker, which is /usr/bin/ld from the
latest version (2.24) of binutils?
No. This has nothing to do with libCppTools.so. As I wrote before the
build system of qt-creator must be changed to provide the missing symbol
by simply adding cppmodelmanager.o to the libCppEditor.so link command.
Out of curiosity, I have downloaded and tried to build qt-creator-3.2.0.
The build failed exactly as you described in commment 0.
The fix is simple, just add __attribute__ ((visibility (default))) to
CppModelManager::ensureUpdated() in src/plugins/cpptools/cppmodelmanager.cpp:
294 __attribute__ ((visibility (default)))
295 void CppModelManager::ensureUpdated()
296 {
This will make _ZN8CppTools8Internal15CppModelManager13ensureUpdatedEv external
for libCppTools.so and everything is fine.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #6 from Jason Merrill jason at gcc dot gnu.org --- I don't see cppmodelmanager in that link command, so I'm guessing ensureUpdated is hidden in a different .so? Certainly compiling the preprocessed file you attached provides a definition of the symbol. Can you also attach a preprocessed cppcodemodelinspectordialog?
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #7 from Chris Clayton chris2553 at googlemail dot com --- Created attachment 33439 -- https://gcc.gnu.org/bugzilla/attachment.cgi?id=33439action=edit Pre-processed cppcodemodelinspectordialog cppcodemodelinspectordialog.ii compressed with xz.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #8 from Markus Trippelsdorf trippels at gcc dot gnu.org --- I don't think this is a compiler bug. cppmodelmanager.o is simply missing in the object file list of the libCppEditor.so link command. And the undefined symbol from cppcodemodelinspectordialog.ii is also correct, because void ensureUpdated() is declared, but not defined in that file.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224
--- Comment #9 from Chris Clayton chris2553 at googlemail dot com ---
That seems odd to me, although I'm happy to be told I'm wrong. I base this on
the fact that reverting the code change from r214208 permits a successful
build. MoreOver, in both the failed and sucessful builds, ensureUpdated is
present in cppmodelmanager.o and that is linked into libCppTools.so as can be
seen by:
[chris:~/rpm/build/qt-creator-opensource-src-3.2.0-fail/qt-creator-3.2.0-build]$
nm lib/qtcreator/plugins/libCppTools.so | grep ensureUpdated
000af430 t _ZN8CppTools8Internal15CppModelManager13ensureUpdatedEv
[chris:~/rpm/build/qt-creator-opensource-src-3.2.0-fail/qt-creator-3.2.0-build]$
cd ~/rpm/build/qt-creator-opensource-src-3.2.0/qt-creator-3.2.0-build
[chris:~/rpm/build/qt-creator-opensource-src-3.2.0/qt-creator-3.2.0-build]$ nm
lib/qtcreator/plugins/libCppTools.so | grep ensureUpdated
000af640 t _ZN8CppTools8Internal15CppModelManager13ensureUpdatedEv
cppmodelmanager.0 is listed (in Makefile) as an object to be included in the
link of libCppTools.so in both builds.
I don't know whether it will be of any help, but I've diffed cppmodelmanager.ii
produced in the two builds and the output is:
--- cppmodelmanager.ii.good 2014-09-02 21:25:02.559799184 +0100
+++ cppmodelmanager.ii.fail 2014-08-22 08:27:06.0 +0100
@@ -18581,23 +18581,7 @@ namespace std __attribute__ ((__visibili
inline basic_istream_CharT, _Traits
getline(basic_istream_CharT, _Traits __is,
basic_string_CharT, _Traits, _Alloc __str)
-{ return std::getline(__is, __str, __is.widen('\n')); }
-
-
-
- templatetypename _CharT, typename _Traits, typename _Alloc
-inline basic_istream_CharT, _Traits
-getline(basic_istream_CharT, _Traits __is,
- basic_string_CharT, _Traits, _Alloc __str, _CharT __delim)
-{ return std::getline(__is, __str, __delim); }
-
-
- templatetypename _CharT, typename _Traits, typename _Alloc
-inline basic_istream_CharT, _Traits
-getline(basic_istream_CharT, _Traits __is,
- basic_string_CharT, _Traits, _Alloc __str)
-{ return std::getline(__is, __str); }
-
+{ return getline(__is, __str, __is.widen('\n')); }
template
basic_istreamchar
@@ -19695,7 +19679,7 @@ namespace __gnu_cxx __attribute__ ((__vi
}
-# 2851 /usr/include/c++/4.9.2/bits/basic_string.h 2 3
+# 2835 /usr/include/c++/4.9.2/bits/basic_string.h 2 3
namespace std __attribute__ ((__visibility__ (default)))
{
@@ -20103,7 +20087,7 @@ namespace std __attribute__ ((__visibili
}
-# 3069 /usr/include/c++/4.9.2/bits/basic_string.h 2 3
+# 3053 /usr/include/c++/4.9.2/bits/basic_string.h 2 3
namespace std __attribute__ ((__visibility__ (default)))
{
@@ -20174,7 +20158,7 @@ namespace std __attribute__ ((__visibili
template
struct __is_fast_hashhashu32string : std::false_type
{ };
-# 3173 /usr/include/c++/4.9.2/bits/basic_string.h 3
+# 3157 /usr/include/c++/4.9.2/bits/basic_string.h 3
}
# 53 /usr/include/c++/4.9.2/string 2 3
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #10 from Markus Trippelsdorf trippels at gcc dot gnu.org --- (In reply to Chris Clayton from comment #9) That seems odd to me, although I'm happy to be told I'm wrong. I base this on the fact that reverting the code change from r214208 permits a successful build. MoreOver, in both the failed and sucessful builds, ensureUpdated is present in cppmodelmanager.o and that is linked into libCppTools.so. Before r214208 the body of virtual QByteArray CppTools::Internal::CppModelManager::definedMacros() (and the other two virtual functions) that call ensureUpdated() were removed: _ZN8CppTools8Internal15CppModelManager13definedMacrosEv/6495 (virtual QByteArray CppTools::Internal::CppModelManager::definedMacros()) @0x7f601c207520 Type: function Body removed by symtab_remove_unreachable_nodes Visibility: external public weak comdat comdat_group:_ZN8CppTools8Internal15CppModelManager13definedMacrosEv one_only virtual Now these virtual function bodies are kept: _ZN8CppTools8Internal15CppModelManager13definedMacrosEv/6495 (virtual QByteArray CppTools::Internal::CppModelManager::definedMacros()) @0x7f67c0347520 Type: function definition analyzed Visibility: externally_visible public weak comdat comdat_group:_ZN8CppTools8Internal15CppModelManager13definedMacrosEv one_only virtual previous sharing asm name: 12475 Address is taken. References: Referring: _ZN9CppEditor8Internal27CppCodeModelInspectorDialog7refreshEv/6819 (addr) (speculative) Availability: available First run: 0 Function flags: body Called by: Calls: _ZN8CppTools8Internal15CppModelManager13ensureUpdatedEv/10759 (1.00 per call) (can throw external) And there is nothing wrong with that AFAICS.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 Jakub Jelinek jakub at gcc dot gnu.org changed: What|Removed |Added CC||jakub at gcc dot gnu.org, ||jason at gcc dot gnu.org --- Comment #4 from Jakub Jelinek jakub at gcc dot gnu.org --- So perhaps the r214208 change? Can you try to back that out and retry?
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #5 from Chris Clayton chris2553 at googlemail dot com --- I reverted the code change from r214208 with the following patch: --- gcc-4.9-20140827-orig/gcc/cp/decl2.c2014-08-20 02:54:40.0 +0100 +++ gcc-4.9-20140827/gcc/cp/decl2.c 2014-09-01 21:07:29.799905722 +0100 @@ -1934,11 +1934,6 @@ decl_needed_p (tree decl) if (flag_keep_inline_dllexport lookup_attribute (dllexport, DECL_ATTRIBUTES (decl))) return true; - /* Virtual functions might be needed for devirtualization. */ - if (flag_devirtualize - TREE_CODE (decl) == FUNCTION_DECL - DECL_VIRTUAL_P (decl)) -return true; /* Otherwise, DECL does not need to be emitted -- yet. A subsequent reference to DECL might cause it to be emitted later. */ return false; With this patch applied to gcc-4.9-20140827, I can now build qt-creator-3.2.0 successfully.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 --- Comment #3 from Chris Clayton chris2553 at googlemail dot com --- Yes, the preprocessed file is the one providing the unresolved references. It surely won't be a surprise to anyone to here that the same failure occurs when building with yesterday's 4.9 snapshot 4.9-20140827.
[Bug c++/62224] [4.9 Regression] Possible regression in gcc-4.9-20140820
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62224 Richard Biener rguenth at gcc dot gnu.org changed: What|Removed |Added Priority|P3 |P1 Target Milestone|--- |4.9.2 Summary|Possible regression in |[4.9 Regression] Possible |gcc-4.9-20140820|regression in ||gcc-4.9-20140820 --- Comment #2 from Richard Biener rguenth at gcc dot gnu.org --- Raising to P1 to be on the radar for the 4.9.2 release. _Not_ confirmed yet. I hope the preprocessed source file is that providing the functions the unresolved references look for.
