[lld] r252979 - [elf2] Implement global dynamic tls.
Rui Ueyama via llvm-commits
llvm-commits at lists.llvm.org
Fri Nov 13 11:12:06 PST 2015
So I think this is the final shot to improve it to the point that we can
call "alpha". Maybe we should write a blog post about that? Developer
community may be interested to know that we are working on a new ELF linker
which we think faster than gold.
On Fri, Nov 13, 2015 at 10:43 AM, Rui Ueyama <ruiu at google.com> wrote:
> Woohoo!
>
> On Fri, Nov 13, 2015 at 7:34 AM, Rafael Espíndola <
> llvm-commits at lists.llvm.org> wrote:
>
>> Now all tests pass is a stage2 build of llvm+clang+lld when linking with
>> lld :-)
>>
>>
>> On 12 November 2015 at 19:28, Michael J. Spencer via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>> > Author: mspencer
>> > Date: Thu Nov 12 18:28:34 2015
>> > New Revision: 252979
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=252979&view=rev
>> > Log:
>> > [elf2] Implement global dynamic tls.
>> >
>> > Modified:
>> > lld/trunk/ELF/InputSection.cpp
>> > lld/trunk/ELF/OutputSections.cpp
>> > lld/trunk/ELF/OutputSections.h
>> > lld/trunk/ELF/Target.cpp
>> > lld/trunk/ELF/Target.h
>> > lld/trunk/ELF/Writer.cpp
>> > lld/trunk/test/elf2/tls-dynamic.s
>> >
>> > Modified: lld/trunk/ELF/InputSection.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=252979&r1=252978&r2=252979&view=diff
>> >
>> ==============================================================================
>> > --- lld/trunk/ELF/InputSection.cpp (original)
>> > +++ lld/trunk/ELF/InputSection.cpp Thu Nov 12 18:28:34 2015
>> > @@ -126,6 +126,14 @@ void InputSectionBase<ELFT>::relocate(
>> > }
>> >
>> > SymbolBody &Body = *File->getSymbolBody(SymIndex)->repl();
>> > +
>> > + if (Type == Target->getTlsGlobalDynamicReloc()) {
>> > + Target->relocateOne(BufLoc, BufEnd, Type, AddrLoc,
>> > + Out<ELFT>::Got->getEntryAddr(Body) +
>> > + getAddend<ELFT>(RI));
>> > + continue;
>> > + }
>> > +
>> > uintX_t SymVA = getSymVA<ELFT>(Body);
>> > if (Target->relocNeedsPlt(Type, Body)) {
>> > SymVA = Out<ELFT>::Plt->getEntryAddr(Body);
>> >
>> > Modified: lld/trunk/ELF/OutputSections.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=252979&r1=252978&r2=252979&view=diff
>> >
>> ==============================================================================
>> > --- lld/trunk/ELF/OutputSections.cpp (original)
>> > +++ lld/trunk/ELF/OutputSections.cpp Thu Nov 12 18:28:34 2015
>> > @@ -80,6 +80,9 @@ GotSection<ELFT>::GotSection()
>> > template <class ELFT> void GotSection<ELFT>::addEntry(SymbolBody *Sym)
>> {
>> > Sym->GotIndex = Target->getGotHeaderEntriesNum() + Entries.size();
>> > Entries.push_back(Sym);
>> > + // Global Dynamic TLS entries take two GOT slots.
>> > + if (Sym->isTLS())
>> > + Entries.push_back(nullptr);
>> > }
>> >
>> > template <class ELFT> uint32_t
>> GotSection<ELFT>::addLocalModuleTlsIndex() {
>> > @@ -187,8 +190,13 @@ template <class ELFT> void RelocationSec
>> > auto *P = reinterpret_cast<Elf_Rel *>(Buf);
>> > Buf += EntrySize;
>> >
>> > - InputSectionBase<ELFT> &C = Rel.C;
>> > - const Elf_Rel &RI = Rel.RI;
>> > + // Skip placeholder for global dynamic TLS relocation pair. It was
>> already
>> > + // handled by the previous relocation.
>> > + if (!Rel.C || !Rel.RI)
>> > + continue;
>> > +
>> > + InputSectionBase<ELFT> &C = *Rel.C;
>> > + const Elf_Rel &RI = *Rel.RI;
>> > uint32_t SymIndex = RI.getSymbol(Config->Mips64EL);
>> > const ObjectFile<ELFT> &File = *C.getFile();
>> > SymbolBody *Body = File.getSymbolBody(SymIndex);
>> > @@ -205,6 +213,17 @@ template <class ELFT> void RelocationSec
>> > continue;
>> > }
>> >
>> > + if (Body && Type == Target->getTlsGlobalDynamicReloc()) {
>> > + P->setSymbolAndType(Body->getDynamicSymbolTableIndex(),
>> > + Target->getTlsModuleIndexReloc(),
>> Config->Mips64EL);
>> > + P->r_offset = Out<ELFT>::Got->getEntryAddr(*Body);
>> > + auto *PNext = reinterpret_cast<Elf_Rel *>(Buf);
>> > + PNext->setSymbolAndType(Body->getDynamicSymbolTableIndex(),
>> > + Target->getTlsOffsetReloc(),
>> Config->Mips64EL);
>> > + PNext->r_offset = Out<ELFT>::Got->getEntryAddr(*Body) +
>> sizeof(uintX_t);
>> > + continue;
>> > + }
>> > +
>> > bool NeedsCopy = Body && Target->relocNeedsCopy(Type, *Body);
>> > bool NeedsGot = Body && Target->relocNeedsGot(Type, *Body);
>> > bool CanBePreempted = canBePreempted(Body, NeedsGot);
>> >
>> > Modified: lld/trunk/ELF/OutputSections.h
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.h?rev=252979&r1=252978&r2=252979&view=diff
>> >
>> ==============================================================================
>> > --- lld/trunk/ELF/OutputSections.h (original)
>> > +++ lld/trunk/ELF/OutputSections.h Thu Nov 12 18:28:34 2015
>> > @@ -170,8 +170,8 @@ private:
>> >
>> > template <class ELFT> struct DynamicReloc {
>> > typedef typename llvm::object::ELFFile<ELFT>::Elf_Rel Elf_Rel;
>> > - InputSectionBase<ELFT> &C;
>> > - const Elf_Rel &RI;
>> > + InputSectionBase<ELFT> *C;
>> > + const Elf_Rel *RI;
>> > };
>> >
>> > template <class ELFT>
>> >
>> > Modified: lld/trunk/ELF/Target.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Target.cpp?rev=252979&r1=252978&r2=252979&view=diff
>> >
>> ==============================================================================
>> > --- lld/trunk/ELF/Target.cpp (original)
>> > +++ lld/trunk/ELF/Target.cpp Thu Nov 12 18:28:34 2015
>> > @@ -216,7 +216,9 @@ X86_64TargetInfo::X86_64TargetInfo() {
>> > PltReloc = R_X86_64_JUMP_SLOT;
>> > RelativeReloc = R_X86_64_RELATIVE;
>> > TlsLocalDynamicReloc = R_X86_64_TLSLD;
>> > + TlsGlobalDynamicReloc = R_X86_64_TLSGD;
>> > TlsModuleIndexReloc = R_X86_64_DTPMOD64;
>> > + TlsOffsetReloc = R_X86_64_DTPOFF64;
>> > LazyRelocations = true;
>> > PltEntrySize = 16;
>> > PltZeroEntrySize = 16;
>> > @@ -335,6 +337,7 @@ void X86_64TargetInfo::relocateOne(uint8
>> > case R_X86_64_GOTPCREL:
>> > case R_X86_64_PLT32:
>> > case R_X86_64_TLSLD:
>> > + case R_X86_64_TLSGD:
>> > write32le(Loc, SA - P);
>> > break;
>> > case R_X86_64_64:
>> >
>> > Modified: lld/trunk/ELF/Target.h
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Target.h?rev=252979&r1=252978&r2=252979&view=diff
>> >
>> ==============================================================================
>> > --- lld/trunk/ELF/Target.h (original)
>> > +++ lld/trunk/ELF/Target.h Thu Nov 12 18:28:34 2015
>> > @@ -30,7 +30,9 @@ public:
>> > unsigned getGotRefReloc() const { return GotRefReloc; }
>> > unsigned getRelativeReloc() const { return RelativeReloc; }
>> > unsigned getTlsLocalDynamicReloc() const { return
>> TlsLocalDynamicReloc; }
>> > + unsigned getTlsGlobalDynamicReloc() const { return
>> TlsGlobalDynamicReloc; }
>> > unsigned getTlsModuleIndexReloc() const { return
>> TlsModuleIndexReloc; }
>> > + unsigned getTlsOffsetReloc() const { return TlsOffsetReloc; }
>> > unsigned getPltZeroEntrySize() const { return PltZeroEntrySize; }
>> > unsigned getPltEntrySize() const { return PltEntrySize; }
>> > bool supportsLazyRelocations() const { return LazyRelocations; }
>> > @@ -70,7 +72,9 @@ protected:
>> > unsigned PltReloc;
>> > unsigned RelativeReloc;
>> > unsigned TlsLocalDynamicReloc = 0;
>> > + unsigned TlsGlobalDynamicReloc = 0;
>> > unsigned TlsModuleIndexReloc;
>> > + unsigned TlsOffsetReloc;
>> > unsigned PltEntrySize = 8;
>> > unsigned PltZeroEntrySize = 0;
>> > unsigned GotHeaderEntriesNum = 0;
>> >
>> > Modified: lld/trunk/ELF/Writer.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=252979&r1=252978&r2=252979&view=diff
>> >
>> ==============================================================================
>> > --- lld/trunk/ELF/Writer.cpp (original)
>> > +++ lld/trunk/ELF/Writer.cpp Thu Nov 12 18:28:34 2015
>> > @@ -203,7 +203,7 @@ void Writer<ELFT>::scanRelocs(
>> > if (Out<ELFT>::LocalModuleTlsIndexOffset == uint32_t(-1)) {
>> > Out<ELFT>::LocalModuleTlsIndexOffset =
>> > Out<ELFT>::Got->addLocalModuleTlsIndex();
>> > - Out<ELFT>::RelaDyn->addReloc({C, RI});
>> > + Out<ELFT>::RelaDyn->addReloc({&C, &RI});
>> > }
>> > continue;
>> > }
>> > @@ -215,6 +215,19 @@ void Writer<ELFT>::scanRelocs(
>> >
>> > if (Body)
>> > Body = Body->repl();
>> > +
>> > + if (Body && Body->isTLS()) {
>> > + if (Type != Target->getTlsGlobalDynamicReloc())
>> > + continue;
>> > + if (Body->isInGot())
>> > + continue;
>> > + Out<ELFT>::Got->addEntry(Body);
>> > + Out<ELFT>::RelaDyn->addReloc({&C, &RI});
>> > + Out<ELFT>::RelaDyn->addReloc({nullptr, nullptr});
>> > + Body->setUsedInDynamicReloc();
>> > + continue;
>> > + }
>> > +
>> > bool NeedsGot = false;
>> > bool NeedsPlt = false;
>> > if (Body) {
>> > @@ -257,9 +270,9 @@ void Writer<ELFT>::scanRelocs(
>> > if (CBP)
>> > Body->setUsedInDynamicReloc();
>> > if (NeedsPlt && Target->supportsLazyRelocations())
>> > - Out<ELFT>::RelaPlt->addReloc({C, RI});
>> > + Out<ELFT>::RelaPlt->addReloc({&C, &RI});
>> > else
>> > - Out<ELFT>::RelaDyn->addReloc({C, RI});
>> > + Out<ELFT>::RelaDyn->addReloc({&C, &RI});
>> > }
>> > }
>> >
>> >
>> > Modified: lld/trunk/test/elf2/tls-dynamic.s
>> > URL:
>> http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf2/tls-dynamic.s?rev=252979&r1=252978&r2=252979&view=diff
>> >
>> ==============================================================================
>> > --- lld/trunk/test/elf2/tls-dynamic.s (original)
>> > +++ lld/trunk/test/elf2/tls-dynamic.s Thu Nov 12 18:28:34 2015
>> > @@ -11,6 +11,10 @@
>> > leaq a at dtpoff(%rax), %rcx
>> > leaq b at dtpoff(%rax), %rcx
>> > .long b at dtpoff, 0
>> > + leaq c at tlsgd(%rip), %rdi
>> > + rex64
>> > + callq __tls_get_addr at PLT
>> > + leaq c at dtpoff(%rax), %rcx
>> >
>> > .global a
>> > .hidden a
>> > @@ -23,8 +27,14 @@ a:
>> > .align 4
>> > b:
>> > .long 0
>> > +
>> > + .global c
>> > + .section .tbss,"awT", at nobits
>> > + .align 4
>> > +c:
>> > + .long 0
>> >
>> > -// Get the address of the got, and check that it has two entries.
>> > +// Get the address of the got, and check that it has 4 entries.
>> >
>> > // CHECK: Sections [
>> > // CHECK: Name: .got
>> > @@ -35,15 +45,18 @@ b:
>> > // CHECK-NEXT: ]
>> > // CHECK-NEXT: Address: 0x20D0
>> > // CHECK-NEXT: Offset:
>> > -// CHECK-NEXT: Size: 16
>> > +// CHECK-NEXT: Size: 32
>> >
>> > // CHECK: Relocations [
>> > // CHECK: Section ({{.+}}) .rela.dyn {
>> > // CHECK-NEXT: 0x20D0 R_X86_64_DTPMOD64 - 0x0
>> > +// CHECK-NEXT: 0x20E0 R_X86_64_DTPMOD64 c 0x0
>> > +// CHECK-NEXT: 0x20E8 R_X86_64_DTPOFF64 c 0x0
>> > // CHECK-NEXT: }
>> >
>> > // 4297 = (0x20D0 + -4) - (0x1000 + 3) // PC relative offset to got
>> entry.
>> > // 4285 = (0x20D0 + -4) - (0x100c + 3) // PC relative offset to got
>> entry.
>> > +// 4267 = (0x20E0 + -4) - (0x102e + 3) // PC relative offset to got
>> entry.
>> >
>> > // DIS: Disassembly of section .text:
>> > // DIS-NEXT: .text:
>> > @@ -57,3 +70,6 @@ b:
>> > // DIS-NEXT: 1028: 00 00
>> > // DIS-NEXT: 102a: 00 00
>> > // DIS-NEXT: 102c: 00 00
>> > +// DIS-NEXT: 102e: {{.+}} leaq 4267(%rip), %rdi
>> > +// DIS-NEXT: 1035: {{.+}} callq
>> > +// DIS-NEXT: 103b: {{.+}} leaq 8(%rax), %rcx
>> >
>> >
>> > _______________________________________________
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>> > llvm-commits at lists.llvm.org
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