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llvm-project/lld/test/ELF/global-offset-table-position.s

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[ELF] Define _GLOBAL_OFFSET_TABLE_ symbol relative to .got On many architectures gcc and clang will recognize _GLOBAL_OFFSET_TABLE_ - . and produce a relocation that can be processed without needing to know the value of _GLOBAL_OFFSET_TABLE_. This is not always the case; for example ARM gcc produces R_ARM_BASE_PREL but clang produces the more general R_ARM_REL32 to _GLOBAL_OFFSET_TABLE_. To evaluate this relocation correctly _GLOBAL_OFFSET_TABLE_ must be defined to be the either the base of the GOT or end of the GOT dependent on architecture.. If/when llvm-mc is changed to recognize _GLOBAL_OFFSET_TABLE_ - . this change will not be necessary for new objects. However there may still be old objects and versions of clang. Differential Revision: https://reviews.llvm.org/D34355 llvm-svn: 306282
2017-06-26 18:22:17 +08:00
// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t
[ELF] - Do --hash-style=both by default. Its PR34712, GNU linkers recently changed default values to "both" of "sysv". Patch do the same for all targets except MIPS, where .gnu.hash section is not yet supported. Code suggested by Rui Ueyama. Differential revision: https://reviews.llvm.org/D38407 llvm-svn: 315051
2017-10-06 17:37:44 +08:00
// RUN: ld.lld --hash-style=sysv -shared %t -o %t2
[ELF] Define _GLOBAL_OFFSET_TABLE_ symbol relative to .got On many architectures gcc and clang will recognize _GLOBAL_OFFSET_TABLE_ - . and produce a relocation that can be processed without needing to know the value of _GLOBAL_OFFSET_TABLE_. This is not always the case; for example ARM gcc produces R_ARM_BASE_PREL but clang produces the more general R_ARM_REL32 to _GLOBAL_OFFSET_TABLE_. To evaluate this relocation correctly _GLOBAL_OFFSET_TABLE_ must be defined to be the either the base of the GOT or end of the GOT dependent on architecture.. If/when llvm-mc is changed to recognize _GLOBAL_OFFSET_TABLE_ - . this change will not be necessary for new objects. However there may still be old objects and versions of clang. Differential Revision: https://reviews.llvm.org/D34355 llvm-svn: 306282
2017-06-26 18:22:17 +08:00
// RUN: llvm-readobj -t %t2 | FileCheck %s
// REQUIRES: x86
// The X86_64 _GLOBAL_OFFSET_TABLE_ is defined at the end of the .got section.
.globl a
.type a,@object
.comm a,4,4
.globl f
.type f,@function
f:
movq a@GOTPCREL(%rip), %rax
.global _start
.type _start,@function
_start:
callq f@PLT
.data
.long _GLOBAL_OFFSET_TABLE_ - .
// CHECK: Name: _GLOBAL_OFFSET_TABLE_
// CHECK-NEXT: Value: 0x30D8
// CHECK-NEXT: Size: 0
// CHECK-NEXT: Binding: Local
// CHECK-NEXT: Type: None (0x0)
// CHECK-NEXT: Other [
// CHECK-NEXT: STV_HIDDEN
// CHECK-NEXT: ]
// CHECK-NEXT: Section: .got