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Fix accounting of tbss. 

We were correctly computing the size contribution of a .tbss input
section (it is none), but we were incorrectly considering the
alignment of the output section: it was advancing Dot instead of
ThreadBssOffset.

As far as I can tell this was always wrong in our linkerscript
implementation, but that became more visible now that the code is
shared with the non linker script case.

llvm-svn: 302107
This commit is contained in:
Rafael Espindola 2017-05-04 03:00:27 +00:00
parent ae1dd58e05
commit 7c4eafa3ee
3 changed files with 18 additions and 19 deletions
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30
lld/ELF/LinkerScript.cpp
View File

@ -495,17 +495,22 @@ void LinkerScript::addOrphanSections(OutputSectionFactory &Factory) {
}
}
static bool isTbss(OutputSection *Sec) {
return (Sec->Flags & SHF_TLS) && Sec->Type == SHT_NOBITS;
uint64_t LinkerScript::advance(uint64_t Size, unsigned Align) {
bool IsTbss = (CurOutSec->Flags & SHF_TLS) && CurOutSec->Type == SHT_NOBITS;
uint64_t Start = IsTbss ? Dot + ThreadBssOffset : Dot;
Start = alignTo(Start, Align);
uint64_t End = Start + Size;
if (IsTbss)
ThreadBssOffset = End - Dot;
else
Dot = End;
return End;
}
void LinkerScript::output(InputSection *S) {
bool IsTbss = isTbss(CurOutSec);
uint64_t Pos = IsTbss ? Dot + ThreadBssOffset : Dot;
Pos = alignTo(Pos, S->Alignment);
S->OutSecOff = Pos - CurOutSec->Addr;
Pos += S->getSize();
uint64_t Pos = advance(S->getSize(), S->Alignment);
S->OutSecOff = Pos - S->getSize() - CurOutSec->Addr;
// Update output section size after adding each section. This is so that
// SIZEOF works correctly in the case below:
@ -524,11 +529,6 @@ void LinkerScript::output(InputSection *S) {
" bytes");
}
}
if (IsTbss)
ThreadBssOffset = Pos - Dot;
else
Dot = Pos;
}
void LinkerScript::switchTo(OutputSection *Sec) {
@ -536,9 +536,7 @@ void LinkerScript::switchTo(OutputSection *Sec) {
return;
CurOutSec = Sec;
Dot = alignTo(Dot, CurOutSec->Alignment);
CurOutSec->Addr = isTbss(CurOutSec) ? Dot + ThreadBssOffset : Dot;
CurOutSec->Addr = advance(0, CurOutSec->Alignment);
// If neither AT nor AT> is specified for an allocatable section, the linker
// will set the LMA such that the difference between VMA and LMA for the

1
lld/ELF/LinkerScript.h
View File

@ -228,6 +228,7 @@ protected:
MemoryRegion *findMemoryRegion(OutputSectionCommand *Cmd);
void switchTo(OutputSection *Sec);
uint64_t advance(uint64_t Size, unsigned Align);
void output(InputSection *Sec);
void process(BaseCommand &Base);

6
lld/test/ELF/tls-offset.s
View File

@ -10,7 +10,7 @@
// RUN: .tbss : { *(.tbss) } \
// RUN: .data.rel.ro : { *(.data.rel.ro) } \
// RUN: }" > %t.script
// RUN: ld.lld -T %t.script %t -o %tout2
// RUN: ld.lld -T %t.script %t -o %tout2
// RUN: echo SCRIPT
// RUN: llvm-readobj -s %tout2 | FileCheck %s
.global _start
@ -61,6 +61,6 @@ _start:
// CHECK-NEXT: SHF_ALLOC
// CHECK-NEXT: SHF_WRITE
// CHECK-NEXT: ]
// CHECK-NEXT: Address: 0x202010
// CHECK-NEXT: Offset: 0x2010
// CHECK-NEXT: Address: 0x202004
// CHECK-NEXT: Offset: 0x2004
// CHECK-NEXT: Size: 4