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

[Rafael Avila de Espindola via llvm-commits]

Done. I also ported a small refactoring to make the merge easier.

Cheers,
Rafael


Hans Wennborg <hans at chromium.org> writes:

> 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
>>> >
>>> >
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>>
>>