[llvm] r185872 - Stop emitting weak symbols into the "coal" sections.
Alexander Potapenko
glider at google.com
Tue Jul 9 02:28:43 PDT 2013
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
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