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ELF/AArch64: Fix dynamic relocation against local symbol in shared objects

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AArch64 TLSDESC for local symbol in shared objects are implemented in a
arch specific manner where the TLSDESC dynamic relocation addend is the
symbol VM inside the TLS block. For instance, with a shared library
created from the code:

--
static __thread int32_t x1;
static __thread int64_t x2;

int32_t foo1 (int32_t x)
{
  x1 += x;
  return x;
}

int64_t foo2 (int64_t x)
{
  x2 += x;
  return x;
}
--

The dynamic relocation should be create as:

Relocations [
  Section (N) .rela.dyn {
    <Address1> R_AARCH64_TLSDESC - 0x0
    <Address2> R_AARCH64_TLSDESC - 0x8
  }
]

Where 0x0 addend in first dynamic relocation is the address of 'x1'
in TLS block and '0x8' is the address of 'x2'.

Checked against test-suite on aarch64-linux-gnu.

llvm-svn: 290099
This commit is contained in:
Adhemerval Zanella 2016-12-19 11:58:01 +00:00
parent 1437f6d710
commit 86513f06be
2 changed files with 50 additions and 2 deletions
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4
lld/ELF/Relocations.cpp
View File

@ -155,8 +155,8 @@ static unsigned handleTlsRelocation(uint32_t Type, SymbolBody &Body,
Config->Shared) {
if (In<ELFT>::Got->addDynTlsEntry(Body)) {
uintX_t Off = In<ELFT>::Got->getGlobalDynOffset(Body);
In<ELFT>::RelaDyn->addReloc(
{Target->TlsDescRel, In<ELFT>::Got, Off, false, &Body, 0});
In<ELFT>::RelaDyn->addReloc({Target->TlsDescRel, In<ELFT>::Got, Off,
!Body.isPreemptible(), &Body, 0});
}
if (Expr != R_TLSDESC_CALL)
C.Relocations.push_back({Expr, Type, Offset, Addend, &Body});

48
lld/test/ELF/aarch64-tlsdesc.s
View File

@ -4,21 +4,69 @@
// RUN: llvm-objdump -d %t.so | FileCheck %s
// RUN: llvm-readobj -r %t.so | FileCheck --check-prefix=REL %s
.text
adrp x0, :tlsdesc:a
ldr x1, [x0, :tlsdesc_lo12:a]
add x0, x0, :tlsdesc_lo12:a
.tlsdesccall a
blr x1
// Create relocation against local TLS symbols where linker should
// create target specific dynamic TLSDESC relocation where addend is
// the symbol VMA in tls block.
// CHECK: 10000: {{.*}} adrp x0, #65536
// CHECK-NEXT: 10004: {{.*}} ldr x1, [x0, #144]
// CHECK-NEXT: 10008: {{.*}} add x0, x0, #144
// CHECK-NEXT: 1000c: {{.*}} blr x1
adrp x0, :tlsdesc:local1
ldr x1, [x0, :tlsdesc_lo12:local1]
add x0, x0, :tlsdesc_lo12:local1
.tlsdesccall a
blr x1
// CHECK: 10010: {{.*}} adrp x0, #65536
// CHECK-NEXT: 10014: {{.*}} ldr x1, [x0, #160]
// CHECK-NEXT: 10018: {{.*}} add x0, x0, #160
// CHECK-NEXT: 1001c: {{.*}} blr x1
adrp x0, :tlsdesc:local2
ldr x1, [x0, :tlsdesc_lo12:local2]
add x0, x0, :tlsdesc_lo12:local2
.tlsdesccall a
blr x1
// CHECK: 10020: {{.*}} adrp x0, #65536
// CHECK-NEXT: 10024: {{.*}} ldr x1, [x0, #176]
// CHECK-NEXT: 10028: {{.*}} add x0, x0, #176
// CHECK-NEXT: 1002c: {{.*}} blr x1
.section .tbss,"awT",@nobits
.type local1,@object
.p2align 2
local1:
.word 0
.size local1, 4
.type local2,@object
.p2align 3
local2:
.xword 0
.size local2, 8
// 0x1000 + 4096 + 160 = 0x20A0
// 0x1000 + 4096 + 176 = 0x20B0
// 0x1000 + 4096 + 144 = 0x2090
// R_AARCH64_TLSDESC - 0x0 -> start of tls block
// R_AARCH64_TLSDESC - 0x8 -> align (sizeof (local1), 8)
// REL: Relocations [
// REL-NEXT: Section (4) .rela.dyn {
// REL-NEXT: 0x200A0 R_AARCH64_TLSDESC - 0x0
// REL-NEXT: 0x200B0 R_AARCH64_TLSDESC - 0x8
// REL-NEXT: 0x20090 R_AARCH64_TLSDESC a 0x0
// REL-NEXT: }
// REL-NEXT: ]