[lld] r292512 - Create _end symbol even if a .so defines it.

[Hans Wennborg via llvm-commits]

sgtm2

On Thu, Jan 19, 2017 at 2:01 PM, Rui Ueyama <ruiu at google.com> wrote:
> Yes.
>
> On Thu, Jan 19, 2017 at 1:30 PM, Rafael Avila de Espindola
> <rafael.espindola at gmail.com> wrote:
>>
>>
>> I would like to port this to 4.0. OK?
>>
>> Cheers,
>> Rafael
>>
>> Rafael Espindola via llvm-commits <llvm-commits at lists.llvm.org> writes:
>>
>> > Author: rafael
>> > Date: Thu Jan 19 13:43:34 2017
>> > New Revision: 292512
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=292512&view=rev
>> > Log:
>> > Create _end symbol even if a .so defines it.
>> >
>> > The freebsd sbrk implementation uses _end to find the initial value of
>> > brk, so it has to be defined in the main binary.
>> >
>> > This should fix the emacs build.
>> >
>> > Added:
>> >     lld/trunk/test/ELF/Inputs/resolution-end.s
>> >     lld/trunk/test/ELF/resolution-end.s
>> > Modified:
>> >     lld/trunk/ELF/SymbolTable.cpp
>> >
>> > Modified: lld/trunk/ELF/SymbolTable.cpp
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SymbolTable.cpp?rev=292512&r1=292511&r2=292512&view=diff
>> >
>> > ==============================================================================
>> > --- lld/trunk/ELF/SymbolTable.cpp (original)
>> > +++ lld/trunk/ELF/SymbolTable.cpp Thu Jan 19 13:43:34 2017
>> > @@ -140,7 +140,7 @@ template <class ELFT>
>> >  DefinedRegular<ELFT> *SymbolTable<ELFT>::addIgnored(StringRef Name,
>> >                                                      uint8_t Visibility)
>> > {
>> >    SymbolBody *S = find(Name);
>> > -  if (!S || !S->isUndefined())
>> > +  if (!S || S->isInCurrentDSO())
>> >      return nullptr;
>> >    return addAbsolute(Name, Visibility);
>> >  }
>> >
>> > Added: lld/trunk/test/ELF/Inputs/resolution-end.s
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/Inputs/resolution-end.s?rev=292512&view=auto
>> >
>> > ==============================================================================
>> > --- lld/trunk/test/ELF/Inputs/resolution-end.s (added)
>> > +++ lld/trunk/test/ELF/Inputs/resolution-end.s Thu Jan 19 13:43:34 2017
>> > @@ -0,0 +1,2 @@
>> > +.data
>> > +        .quad _end
>> >
>> > Added: lld/trunk/test/ELF/resolution-end.s
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/resolution-end.s?rev=292512&view=auto
>> >
>> > ==============================================================================
>> > --- lld/trunk/test/ELF/resolution-end.s (added)
>> > +++ lld/trunk/test/ELF/resolution-end.s Thu Jan 19 13:43:34 2017
>> > @@ -0,0 +1,39 @@
>> > +# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o
>> > +# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux
>> > %p/Inputs/resolution-end.s -o %t2.o
>> > +# RUN: ld.lld -shared -o %t2.so %t2.o
>> > +# RUN: ld.lld %t1.o %t2.so -o %t
>> > +# RUN: llvm-readobj -t -s -section-data  %t | FileCheck %s
>> > +# REQUIRES: x86
>> > +
>> > +# Test that we resolve _end to the this executable.
>> > +
>> > +# CHECK:      Name: .text
>> > +# CHECK-NEXT: Type: SHT_PROGBITS
>> > +# CHECK-NEXT: Flags [
>> > +# CHECK-NEXT:   SHF_ALLOC
>> > +# CHECK-NEXT:   SHF_EXECINSTR
>> > +# CHECK-NEXT: ]
>> > +# CHECK-NEXT: Address:
>> > +# CHECK-NEXT: Offset:
>> > +# CHECK-NEXT: Size:
>> > +# CHECK-NEXT: Link:
>> > +# CHECK-NEXT: Info:
>> > +# CHECK-NEXT: AddressAlignment:
>> > +# CHECK-NEXT: EntrySize:
>> > +# CHECK-NEXT: SectionData (
>> > +# CHECK-NEXT:   0000: 80202000 00000000
>> > +# CHECK-NEXT: )
>> > +
>> > +# CHECK:      Symbol {
>> > +# CHECK:        Name: _end
>> > +# CHECK-NEXT:   Value: 0x202080
>> > +# CHECK-NEXT:   Size:
>> > +# CHECK-NEXT:   Binding: Global
>> > +# CHECK-NEXT:   Type:
>> > +# CHECK-NEXT:   Other:
>> > +# CHECK-NEXT:   Section:
>> > +# CHECK-NEXT: }
>> > +
>> > +.global _start
>> > +_start:
>> > +.quad _end
>> >
>> >
>> > _______________________________________________
>> > llvm-commits mailing list
>> > llvm-commits at lists.llvm.org
>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
>