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llvm-project/llvm/test/MC/ELF/target-in-same-section.s

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[MC][ELF] Emit a relocation if target is defined in the same section and is non-local For a target symbol defined in the same section, currently we don't emit a relocation if VariantKind is VK_None (with few exceptions like RISC-V relaxation), while GNU as emits one. This causes program behavior differences with and without -ffunction-sections, and can break intended symbol interposition in a -shared link. ``` .globl foo foo: call foo # no relocation. On other targets, may be written as b foo, etc call bar # a relocation if bar is in another section (e.g. -ffunction-sections) call foo@plt # a relocation ``` Unify these cases by always emitting a relocation. If we ever want to optimize `call foo` in -shared links, we should emit a STB_LOCAL alias and call via the alias. ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does. X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does. ELF/relax.s: rewrite the test as target-in-same-section.s . We omitted relocations to `global` and now emit R_X86_64_PLT32. Note, GNU as does not emit a relocation for `jmp global` (maybe its own bug). Our new behavior is compatible except `jmp global`. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D72197
2020-01-04 13:44:57 +08:00
## For a target defined in the same section, create a relocation if the
## symbol is not local, otherwise resolve the fixup statically.
# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t
# RUN: llvm-readobj -r %t | FileCheck --check-prefix=RELOC %s
# RUN: llvm-objdump -d --no-show-raw-insn %t | FileCheck %s
# RELOC: .rela.text {
# RELOC-NEXT: 0x5 R_X86_64_PLT32 global 0xFFFFFFFFFFFFFFFC
# RELOC-NEXT: 0xA R_X86_64_PLT32 weak 0xFFFFFFFFFFFFFFFC
# RELOC-NEXT: 0x19 R_X86_64_PLT32 global 0xFFFFFFFFFFFFFFFC
# RELOC-NEXT: 0x1E R_X86_64_PLT32 weak 0xFFFFFFFFFFFFFFFC
[MC] Don't resolve relocations referencing STB_LOCAL STT_GNU_IFUNC
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# RELOC-NEXT: 0x23 R_X86_64_PLT32 ifunc 0xFFFFFFFFFFFFFFFC
[MC][ELF] Emit a relocation if target is defined in the same section and is non-local For a target symbol defined in the same section, currently we don't emit a relocation if VariantKind is VK_None (with few exceptions like RISC-V relaxation), while GNU as emits one. This causes program behavior differences with and without -ffunction-sections, and can break intended symbol interposition in a -shared link. ``` .globl foo foo: call foo # no relocation. On other targets, may be written as b foo, etc call bar # a relocation if bar is in another section (e.g. -ffunction-sections) call foo@plt # a relocation ``` Unify these cases by always emitting a relocation. If we ever want to optimize `call foo` in -shared links, we should emit a STB_LOCAL alias and call via the alias. ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does. X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does. ELF/relax.s: rewrite the test as target-in-same-section.s . We omitted relocations to `global` and now emit R_X86_64_PLT32. Note, GNU as does not emit a relocation for `jmp global` (maybe its own bug). Our new behavior is compatible except `jmp global`. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D72197
2020-01-04 13:44:57 +08:00
# RELOC-NEXT: }
# CHECK: 0: jmp
# CHECK-NEXT: 2: jmp
# CHECK-NEXT: 4: jmp
# CHECK-NEXT: 9: jmp
# CHECK-NEXT: e: callq
# CHECK-NEXT: 13: callq
# CHECK-NEXT: 18: callq
# CHECK-NEXT: 1d: callq
[MC] Don't resolve relocations referencing STB_LOCAL STT_GNU_IFUNC
2020-01-14 15:35:57 +08:00
# CHECK-NEXT: 22: callq
# CHECK-NEXT: 27: retq
[MC][ELF] Emit a relocation if target is defined in the same section and is non-local For a target symbol defined in the same section, currently we don't emit a relocation if VariantKind is VK_None (with few exceptions like RISC-V relaxation), while GNU as emits one. This causes program behavior differences with and without -ffunction-sections, and can break intended symbol interposition in a -shared link. ``` .globl foo foo: call foo # no relocation. On other targets, may be written as b foo, etc call bar # a relocation if bar is in another section (e.g. -ffunction-sections) call foo@plt # a relocation ``` Unify these cases by always emitting a relocation. If we ever want to optimize `call foo` in -shared links, we should emit a STB_LOCAL alias and call via the alias. ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does. X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does. ELF/relax.s: rewrite the test as target-in-same-section.s . We omitted relocations to `global` and now emit R_X86_64_PLT32. Note, GNU as does not emit a relocation for `jmp global` (maybe its own bug). Our new behavior is compatible except `jmp global`. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D72197
2020-01-04 13:44:57 +08:00
.globl global
.weak weak
[MC] Don't resolve relocations referencing STB_LOCAL STT_GNU_IFUNC
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.type ifunc,@gnu_indirect_function
[MC][ELF] Emit a relocation if target is defined in the same section and is non-local For a target symbol defined in the same section, currently we don't emit a relocation if VariantKind is VK_None (with few exceptions like RISC-V relaxation), while GNU as emits one. This causes program behavior differences with and without -ffunction-sections, and can break intended symbol interposition in a -shared link. ``` .globl foo foo: call foo # no relocation. On other targets, may be written as b foo, etc call bar # a relocation if bar is in another section (e.g. -ffunction-sections) call foo@plt # a relocation ``` Unify these cases by always emitting a relocation. If we ever want to optimize `call foo` in -shared links, we should emit a STB_LOCAL alias and call via the alias. ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does. X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does. ELF/relax.s: rewrite the test as target-in-same-section.s . We omitted relocations to `global` and now emit R_X86_64_PLT32. Note, GNU as does not emit a relocation for `jmp global` (maybe its own bug). Our new behavior is compatible except `jmp global`. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D72197
2020-01-04 13:44:57 +08:00
global:
weak:
local:
.set var,global
[MC] Don't resolve relocations referencing STB_LOCAL STT_GNU_IFUNC
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ifunc:
[MC][ELF] Emit a relocation if target is defined in the same section and is non-local For a target symbol defined in the same section, currently we don't emit a relocation if VariantKind is VK_None (with few exceptions like RISC-V relaxation), while GNU as emits one. This causes program behavior differences with and without -ffunction-sections, and can break intended symbol interposition in a -shared link. ``` .globl foo foo: call foo # no relocation. On other targets, may be written as b foo, etc call bar # a relocation if bar is in another section (e.g. -ffunction-sections) call foo@plt # a relocation ``` Unify these cases by always emitting a relocation. If we ever want to optimize `call foo` in -shared links, we should emit a STB_LOCAL alias and call via the alias. ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does. X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does. ELF/relax.s: rewrite the test as target-in-same-section.s . We omitted relocations to `global` and now emit R_X86_64_PLT32. Note, GNU as does not emit a relocation for `jmp global` (maybe its own bug). Our new behavior is compatible except `jmp global`. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D72197
2020-01-04 13:44:57 +08:00
jmp var
jmp local
jmp global
jmp weak
call var
call local
call global
call weak
[MC] Don't resolve relocations referencing STB_LOCAL STT_GNU_IFUNC
2020-01-14 15:35:57 +08:00
call ifunc
[MC][ELF] Emit a relocation if target is defined in the same section and is non-local For a target symbol defined in the same section, currently we don't emit a relocation if VariantKind is VK_None (with few exceptions like RISC-V relaxation), while GNU as emits one. This causes program behavior differences with and without -ffunction-sections, and can break intended symbol interposition in a -shared link. ``` .globl foo foo: call foo # no relocation. On other targets, may be written as b foo, etc call bar # a relocation if bar is in another section (e.g. -ffunction-sections) call foo@plt # a relocation ``` Unify these cases by always emitting a relocation. If we ever want to optimize `call foo` in -shared links, we should emit a STB_LOCAL alias and call via the alias. ARM/thumb2-beq-fixup.s: we now emit a relocation to global_thumb_fn as GNU as does. X86/Inputs/align-branch-64-2.s: we now emit R_X86_64_PLT32 to foo as GNU does. ELF/relax.s: rewrite the test as target-in-same-section.s . We omitted relocations to `global` and now emit R_X86_64_PLT32. Note, GNU as does not emit a relocation for `jmp global` (maybe its own bug). Our new behavior is compatible except `jmp global`. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D72197
2020-01-04 13:44:57 +08:00
ret