[llvm] r185872 - Stop emitting weak symbols into the "coal" sections.
Alexander Potapenko
glider at google.com
Tue Jul 9 03:02:09 PDT 2013
Reverted in r185923.
On Tue, Jul 9, 2013 at 1:28 PM, Alexander Potapenko <glider at google.com> wrote:
> Hi Bill,
>
> This patch has totally broken `make check-asan` on Mac.
> ld reports numerous warnings like this:
> ld: warning: direct access in __GLOBAL__I_a to global weak symbol
> ___asan_mapping_scale means the weak symbol cannot be overridden at
> runtime. This was likely caused by different translation units being
> compiled with different visibility settings.
> ld: warning: direct access in __ZL15TestLargeMallocm to global weak
> symbol __ZTSN7testing8internal15TestFactoryImplI36AddressSanitizer_HugeMallocTest_TestEE
> means the weak symbol cannot be overridden at runtime. This was likely
> caused by different translation units being compiled with different
> visibility settings.
>
> , after that a huge number of tests die with incorrect ASan reports.
>
> Reverting your patch locally fixes the problem on my machine.
>
> On Tue, Jul 9, 2013 at 1:34 AM, Bill Wendling <isanbard at gmail.com> wrote:
>> Author: void
>> Date: Mon Jul 8 16:34:52 2013
>> New Revision: 185872
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=185872&view=rev
>> Log:
>> Stop emitting weak symbols into the "coal" sections.
>>
>> The Mach-O linker has been able to support the weak-def bit on any symbol for
>> quite a while now. The compiler however continued to place these symbols into a
>> "coal" section, which required the linker to map them back to the base section
>> name.
>>
>> Replace the sections like this:
>>
>> __TEXT/__textcoal_nt instead use __TEXT/__text
>> __TEXT/__const_coal instead use __TEXT/__const
>> __DATA/__datacoal_nt instead use __DATA/__data
>>
>> <rdar://problem/14265330>
>>
>> Added:
>> llvm/trunk/test/CodeGen/X86/no-coal-sections.ll
>> Modified:
>> llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
>> llvm/trunk/test/CodeGen/X86/global-sections.ll
>>
>> Modified: llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp?rev=185872&r1=185871&r2=185872&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp (original)
>> +++ llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp Mon Jul 8 16:34:52 2013
>> @@ -524,14 +524,14 @@ const MCSection *TargetLoweringObjectFil
>> SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
>> Mangler *Mang, const TargetMachine &TM) const {
>> if (Kind.isText())
>> - return GV->isWeakForLinker() ? TextCoalSection : TextSection;
>> -
>> - // If this is weak/linkonce, put this in a coalescable section, either in text
>> - // or data depending on if it is writable.
>> + return TextSection;
>> +
>> + // If this is weak/linkonce, put this in a read only or data section depending
>> + // on whether or not it's writable.
>> if (GV->isWeakForLinker()) {
>> if (Kind.isReadOnly())
>> - return ConstTextCoalSection;
>> - return DataCoalSection;
>> + return ReadOnlySection;
>> + return DataSection;
>> }
>>
>> // FIXME: Alignment check should be handled by section classifier.
>>
>> Modified: llvm/trunk/test/CodeGen/X86/global-sections.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/global-sections.ll?rev=185872&r1=185871&r2=185872&view=diff
>> ==============================================================================
>> --- llvm/trunk/test/CodeGen/X86/global-sections.ll (original)
>> +++ llvm/trunk/test/CodeGen/X86/global-sections.ll Mon Jul 8 16:34:52 2013
>> @@ -20,7 +20,7 @@
>>
>> ; TODO: linux drops this into .rodata, we drop it into ".gnu.linkonce.r.G2"
>>
>> -; DARWIN: .section __TEXT,__const_coal,coalesced
>> +; DARWIN: .section __TEXT,__const
>> ; DARWIN: _G2:
>> ; DARWIN: .long 42
>>
>> @@ -70,7 +70,6 @@
>> ; LINUX: .weak foo_20_bar
>> ; LINUX: foo_20_bar:
>>
>> -; DARWIN: .section __DATA,__datacoal_nt,coalesced
>> ; DARWIN: .globl "_foo bar"
>> ; DARWIN: .weak_definition "_foo bar"
>> ; DARWIN: "_foo bar":
>> @@ -85,7 +84,7 @@
>> ; LINUX: .byte 1
>> ; LINUX: .size G6, 1
>>
>> -; DARWIN: .section __TEXT,__const_coal,coalesced
>> +; DARWIN: .section __TEXT,__const
>> ; DARWIN: .globl _G6
>> ; DARWIN: .weak_definition _G6
>> ; DARWIN:_G6:
>> @@ -131,7 +130,7 @@
>> @G10 = weak global [100 x i32] zeroinitializer, align 32 ; <[100 x i32]*> [#uses=0]
>>
>>
>> -; DARWIN: .section __DATA,__datacoal_nt,coalesced
>> +; DARWIN: .section __DATA,__data
>> ; DARWIN: .globl _G10
>> ; DARWIN: .weak_definition _G10
>> ; DARWIN: .align 5
>>
>> Added: llvm/trunk/test/CodeGen/X86/no-coal-sections.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/no-coal-sections.ll?rev=185872&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/CodeGen/X86/no-coal-sections.ll (added)
>> +++ llvm/trunk/test/CodeGen/X86/no-coal-sections.ll Mon Jul 8 16:34:52 2013
>> @@ -0,0 +1,74 @@
>> +; RUN: llc < %s -mtriple x86_64-apple-macosx10 | FileCheck %s
>> +; <rdar://problem/14265330>
>> +
>> +; CHECK: .section __TEXT,__text
>> +; CHECK-NOT: .section __TEXT,__textcoal_nt
>> +; CHECK: .globl __ZN6TrickyIiLi0EEC1Ev
>> +
>> +; CHECK: .section __DATA,__data
>> +; CHECK-NOT: .section __DATA,__datacoal_nt
>> +; CHECK: .globl __ZTV6TrickyIiLi0EE
>> +
>> +; CHECK: .section __TEXT,__const
>> +; CHECK-NOT: .section __TEXT,__const_coal
>> +; CHECK: .globl __ZTS6TrickyIiLi0EE
>> +
>> +; CHECK: .section __DATA,__data
>> +; CHECK-NOT: .section __DATA,__datacoal_nt
>> +; CHECK: .globl __ZTI6TrickyIiLi0EE
>> +
>> +%class.Tricky = type { i32 (...)**, %union.anon }
>> +%union.anon = type { i32 }
>> +
>> + at _ZTV6TrickyIiLi0EE = linkonce_odr unnamed_addr constant [4 x i8*] [i8* null, i8* bitcast ({ i8*, i8* }* @_ZTI6TrickyIiLi0EE to i8*), i8* bitcast (void (%class.Tricky*)* @_ZN6TrickyIiLi0EED1Ev to i8*), i8* bitcast (void (%class.Tricky*)* @_ZN6TrickyIiLi0EED0Ev to i8*)]
>> + at _ZTVN10__cxxabiv117__class_type_infoE = external global i8*
>> + at _ZTS6TrickyIiLi0EE = linkonce_odr constant [15 x i8] c"6TrickyIiLi0EE\00"
>> + at _ZTI6TrickyIiLi0EE = linkonce_odr unnamed_addr constant { i8*, i8* } { i8* bitcast (i8** getelementptr inbounds (i8** @_ZTVN10__cxxabiv117__class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([15 x i8]* @_ZTS6TrickyIiLi0EE, i32 0, i32 0) }
>> +
>> +; Function Attrs: nounwind ssp uwtable
>> +define i32 @main() {
>> +entry:
>> + %ok = alloca %class.Tricky, align 8
>> + call void @_ZN6TrickyIiLi0EEC1Ev(%class.Tricky* %ok)
>> + ret i32 0
>> +}
>> +
>> +; Function Attrs: inlinehint nounwind ssp uwtable
>> +define linkonce_odr void @_ZN6TrickyIiLi0EEC1Ev(%class.Tricky* nocapture %this) unnamed_addr align 2 {
>> +entry:
>> + tail call void @_ZN6TrickyIiLi0EEC2Ev(%class.Tricky* %this)
>> + ret void
>> +}
>> +
>> +; Function Attrs: nounwind readnone ssp uwtable
>> +define linkonce_odr void @_ZN6TrickyIiLi0EED1Ev(%class.Tricky* nocapture %this) unnamed_addr align 2 {
>> +entry:
>> + ret void
>> +}
>> +
>> +; Function Attrs: nounwind readnone ssp uwtable
>> +define linkonce_odr void @_ZN6TrickyIiLi0EED2Ev(%class.Tricky* nocapture %this) unnamed_addr align 2 {
>> +entry:
>> + ret void
>> +}
>> +
>> +; Function Attrs: inlinehint nounwind ssp uwtable
>> +define linkonce_odr void @_ZN6TrickyIiLi0EEC2Ev(%class.Tricky* nocapture %this) unnamed_addr align 2 {
>> +entry:
>> + %0 = getelementptr inbounds %class.Tricky* %this, i64 0, i32 0
>> + store i32 (...)** bitcast (i8** getelementptr inbounds ([4 x i8*]* @_ZTV6TrickyIiLi0EE, i64 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
>> + ret void
>> +}
>> +
>> +; Function Attrs: nounwind ssp uwtable
>> +define linkonce_odr void @_ZN6TrickyIiLi0EED0Ev(%class.Tricky* %this) unnamed_addr align 2 {
>> +invoke.cont:
>> + %0 = bitcast %class.Tricky* %this to i8*
>> + tail call void @_ZdlPv(i8* %0)
>> + ret void
>> +}
>> +
>> +declare i32 @__gxx_personality_v0(...)
>> +
>> +; Function Attrs: nounwind
>> +declare void @_ZdlPv(i8*)
>>
>>
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>
>
>
> --
> Alexander Potapenko
> Software Engineer
> Google Moscow
--
Alexander Potapenko
Software Engineer
Google Moscow
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