| Message ID | 20110612145443.GA7920@kam.mff.cuni.cz |
|---|---|
| State | New |
| Headers | show |
On Sun, Jun 12, 2011 at 7:54 AM, Jan Hubicka <hubicka@ucw.cz> wrote: >> >> This also pretty much destroyed C++ for ia32: >> >> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49378 >> http://gcc.gnu.org/ml/gcc-regression/2011-06/msg00159.html > > Hi, > It seems somewhat amazing that we hit kernel sensitive miscompilation here. > The problem most probably is the fact that thunks and functions with thunks can become > local. This is correct since thunks are represented as direct calls now, but this > makes i386 to use local ABI when calling or compiling them. > > Does the following patch help? We may also need to look for the presence of thunk > callers. > > Index: ipa.c > =================================================================== > --- ipa.c (revision 174958) > +++ ipa.c (working copy) > @@ -120,6 +120,7 @@ static bool > cgraph_non_local_node_p_1 (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED) > { > return !(cgraph_only_called_directly_or_aliased_p (node) > + && !ipa_ref_has_aliases_p (&node->ref_list) > && node->analyzed > && !DECL_EXTERNAL (node->decl) > && !node->local.externally_visible > @@ -132,7 +133,11 @@ cgraph_non_local_node_p_1 (struct cgraph > static bool > cgraph_local_node_p (struct cgraph_node *node) > { > - return !cgraph_for_node_and_aliases (cgraph_function_or_thunk_node (node, NULL), > + struct cgraph_node *n = cgraph_function_or_thunk_node (node, NULL); > + > + if (n->thunk.thunk_p) > + return false; > + return !cgraph_for_node_and_aliases (n, > cgraph_non_local_node_p_1, NULL, true); > > } > I am testing it now. Will know the results in 2 hours. Thanks.
> I am testing it now. Will know the results in 2 hours. Thanks. Could you also send me the preprocessed source for future.o? The object file I am getting don't have the bug you report, that is most probably due to glibc difference. Honza > > Thanks. > > -- > H.J.
On Sun, Jun 12, 2011 at 7:54 AM, Jan Hubicka <hubicka@ucw.cz> wrote: >> >> This also pretty much destroyed C++ for ia32: >> >> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49378 >> http://gcc.gnu.org/ml/gcc-regression/2011-06/msg00159.html > > Hi, > It seems somewhat amazing that we hit kernel sensitive miscompilation here. > The problem most probably is the fact that thunks and functions with thunks can become > local. This is correct since thunks are represented as direct calls now, but this > makes i386 to use local ABI when calling or compiling them. > For x86-64, we use the same ABI for local and global. But RAX seems used and uninitialized in thunk.
On Sun, Jun 12, 2011 at 8:01 AM, H.J. Lu <hjl.tools@gmail.com> wrote: > On Sun, Jun 12, 2011 at 7:54 AM, Jan Hubicka <hubicka@ucw.cz> wrote: >>> >>> This also pretty much destroyed C++ for ia32: >>> >>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49378 >>> http://gcc.gnu.org/ml/gcc-regression/2011-06/msg00159.html >> >> Hi, >> It seems somewhat amazing that we hit kernel sensitive miscompilation here. >> The problem most probably is the fact that thunks and functions with thunks can become >> local. This is correct since thunks are represented as direct calls now, but this >> makes i386 to use local ABI when calling or compiling them. >> >> Does the following patch help? We may also need to look for the presence of thunk >> callers. >> >> Index: ipa.c >> =================================================================== >> --- ipa.c (revision 174958) >> +++ ipa.c (working copy) >> @@ -120,6 +120,7 @@ static bool >> cgraph_non_local_node_p_1 (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED) >> { >> return !(cgraph_only_called_directly_or_aliased_p (node) >> + && !ipa_ref_has_aliases_p (&node->ref_list) >> && node->analyzed >> && !DECL_EXTERNAL (node->decl) >> && !node->local.externally_visible >> @@ -132,7 +133,11 @@ cgraph_non_local_node_p_1 (struct cgraph >> static bool >> cgraph_local_node_p (struct cgraph_node *node) >> { >> - return !cgraph_for_node_and_aliases (cgraph_function_or_thunk_node (node, NULL), >> + struct cgraph_node *n = cgraph_function_or_thunk_node (node, NULL); >> + >> + if (n->thunk.thunk_p) >> + return false; >> + return !cgraph_for_node_and_aliases (n, >> cgraph_non_local_node_p_1, NULL, true); >> >> } >> > > I am testing it now. Will know the results in 2 hours. > Yes, it fixes C++ regressions. Thanks.
> On Sun, Jun 12, 2011 at 7:54 AM, Jan Hubicka <hubicka@ucw.cz> wrote: > >> > >> This also pretty much destroyed C++ for ia32: > >> > >> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49378 > >> http://gcc.gnu.org/ml/gcc-regression/2011-06/msg00159.html > > > > Hi, > > It seems somewhat amazing that we hit kernel sensitive miscompilation here. > > The problem most probably is the fact that thunks and functions with thunks can become > > local. This is correct since thunks are represented as direct calls now, but this > > makes i386 to use local ABI when calling or compiling them. > > > > For x86-64, we use the same ABI for local and global. But RAX seems > used and uninitialized in thunk. 000000000006d270 <_ZN12_GLOBAL__N_121system_error_categoryD0Ev>: 6d270: 48 8d 05 79 d4 27 00 lea 0x27d479(%rip),%rax # 2ea6f0 <_ZTVN12_GLOBAL__N_121system_error_categoryE+0x10> 6d277: 53 push %rbx 6d278: 48 89 fb mov %rdi,%rbx 6d27b: 48 89 07 mov %rax,(%rdi) 6d27e: e8 55 a0 fe ff callq 572d8 <_ZNSt14error_categoryD2Ev@plt> 6d283: 48 89 df mov %rbx,%rdi 6d286: 5b pop %rbx 6d287: e9 2c 9d fe ff jmpq 56fb8 <_ZdlPv@plt> 6d28c: 90 nop 6d28d: 90 nop 6d28e: 90 nop 6d28f: 90 nop I don't see uinitialized RAX here. It is set by the first LEA I will commit the patch now to unbreak x86 and work on more proper solution after debugging the plugin usses. Thanks for testing! Honza > > -- > H.J.
On Sun, Jun 12, 2011 at 9:33 AM, Jan Hubicka <hubicka@ucw.cz> wrote: >> On Sun, Jun 12, 2011 at 7:54 AM, Jan Hubicka <hubicka@ucw.cz> wrote: >> >> >> >> This also pretty much destroyed C++ for ia32: >> >> >> >> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49378 >> >> http://gcc.gnu.org/ml/gcc-regression/2011-06/msg00159.html >> > >> > Hi, >> > It seems somewhat amazing that we hit kernel sensitive miscompilation here. >> > The problem most probably is the fact that thunks and functions with thunks can become >> > local. This is correct since thunks are represented as direct calls now, but this >> > makes i386 to use local ABI when calling or compiling them. >> > >> >> For x86-64, we use the same ABI for local and global. But RAX seems >> used and uninitialized in thunk. > 000000000006d270 <_ZN12_GLOBAL__N_121system_error_categoryD0Ev>: > 6d270: 48 8d 05 79 d4 27 00 lea 0x27d479(%rip),%rax # > 2ea6f0 <_ZTVN12_GLOBAL__N_121system_error_categoryE+0x10> > 6d277: 53 push %rbx > 6d278: 48 89 fb mov %rdi,%rbx > 6d27b: 48 89 07 mov %rax,(%rdi) > 6d27e: e8 55 a0 fe ff callq 572d8 > <_ZNSt14error_categoryD2Ev@plt> > 6d283: 48 89 df mov %rbx,%rdi > 6d286: 5b pop %rbx > 6d287: e9 2c 9d fe ff jmpq 56fb8 <_ZdlPv@plt> > 6d28c: 90 nop > 6d28d: 90 nop > 6d28e: 90 nop > 6d28f: 90 nop > > I don't see uinitialized RAX here. It is set by the first LEA You are right.
Index: ipa.c =================================================================== --- ipa.c (revision 174958) +++ ipa.c (working copy) @@ -120,6 +120,7 @@ static bool cgraph_non_local_node_p_1 (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED) { return !(cgraph_only_called_directly_or_aliased_p (node) + && !ipa_ref_has_aliases_p (&node->ref_list) && node->analyzed && !DECL_EXTERNAL (node->decl) && !node->local.externally_visible @@ -132,7 +133,11 @@ cgraph_non_local_node_p_1 (struct cgraph static bool cgraph_local_node_p (struct cgraph_node *node) { - return !cgraph_for_node_and_aliases (cgraph_function_or_thunk_node (node, NULL), + struct cgraph_node *n = cgraph_function_or_thunk_node (node, NULL); + + if (n->thunk.thunk_p) + return false; + return !cgraph_for_node_and_aliases (n, cgraph_non_local_node_p_1, NULL, true); }