maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/lld/test/ELF/wrap-entry.s

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

18 lines
401 B
ArmAsm
Raw Normal View History

Change how we handle -wrap. We have an issue with -wrap that the option doesn't work well when renamed symbols get PLT entries. I'll explain what is the issue and how this patch solves it. For one -wrap option, we have three symbols: foo, wrap_foo and real_foo. Currently, we use memcpy to overwrite wrapped symbols so that they get the same contents. This works in most cases but doesn't when the relocation processor sets some flags in the symbol. memcpy'ed symbols are just aliases, so they always have to have the same contents, but the relocation processor breaks that assumption. r336609 is an attempt to fix the issue by memcpy'ing again after processing relocations, so that symbols that are out of sync get the same contents again. That works in most cases as well, but it breaks ASan build in a mysterious way. We could probably fix the issue by choosing symbol attributes that need to be copied after they are updated. But it feels too complicated to me. So, in this patch, I fixed it once and for all. With this patch, we no longer memcpy symbols. All references to renamed symbols point to new symbols after wrapSymbols() is done. Differential Revision: https://reviews.llvm.org/D50569 llvm-svn: 340387
2018-08-22 15:02:26 +08:00
// REQUIRES: x86
// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
// RUN: ld.lld -o %t.exe %t.o -wrap=_start
[ELF][test] Improve and reorganize another set of tests Add file-level comments Replace trivial Input/*.s with echo ... | llvm-mc Delete insignificant addresses to make them more tolerant to layout changes Simplify test output Merge merge-section-types.s into compatible-section-types.s and add a missed case Merge gnu-ifunc-gotpcrel.s (added in D19517) into gnu-ifunc-dso.s (added in D35119) and add missed cases Delete typed-undef.s - covered by executable-undefined-ignoreall.s Delete emit-relocs-shared.s - covered by emit-relocs-merge.s Replace copy-rel-pie.s and copy-rel-pie2.s with canonical-plt-pcrel.s, canonical-plt-symbolic.s and copy-rel.s: add -no-pie cases. add a case that a canonical PLT can be created for STT_GNU_IFUNC. The logic in Symbols.h was untested: // ctor of SharedSymbol if (this->type == llvm::ELF::STT_GNU_IFUNC) this->type = llvm::ELF::STT_FUNC; llvm-svn: 371361
2019-09-09 11:35:14 +08:00
// RUN: llvm-readobj --symbols -h %t.exe | FileCheck %s
Change how we handle -wrap. We have an issue with -wrap that the option doesn't work well when renamed symbols get PLT entries. I'll explain what is the issue and how this patch solves it. For one -wrap option, we have three symbols: foo, wrap_foo and real_foo. Currently, we use memcpy to overwrite wrapped symbols so that they get the same contents. This works in most cases but doesn't when the relocation processor sets some flags in the symbol. memcpy'ed symbols are just aliases, so they always have to have the same contents, but the relocation processor breaks that assumption. r336609 is an attempt to fix the issue by memcpy'ing again after processing relocations, so that symbols that are out of sync get the same contents again. That works in most cases as well, but it breaks ASan build in a mysterious way. We could probably fix the issue by choosing symbol attributes that need to be copied after they are updated. But it feels too complicated to me. So, in this patch, I fixed it once and for all. With this patch, we no longer memcpy symbols. All references to renamed symbols point to new symbols after wrapSymbols() is done. Differential Revision: https://reviews.llvm.org/D50569 llvm-svn: 340387
2018-08-22 15:02:26 +08:00
[ELF][test] Improve and reorganize another set of tests Add file-level comments Replace trivial Input/*.s with echo ... | llvm-mc Delete insignificant addresses to make them more tolerant to layout changes Simplify test output Merge merge-section-types.s into compatible-section-types.s and add a missed case Merge gnu-ifunc-gotpcrel.s (added in D19517) into gnu-ifunc-dso.s (added in D35119) and add missed cases Delete typed-undef.s - covered by executable-undefined-ignoreall.s Delete emit-relocs-shared.s - covered by emit-relocs-merge.s Replace copy-rel-pie.s and copy-rel-pie2.s with canonical-plt-pcrel.s, canonical-plt-symbolic.s and copy-rel.s: add -no-pie cases. add a case that a canonical PLT can be created for STT_GNU_IFUNC. The logic in Symbols.h was untested: // ctor of SharedSymbol if (this->type == llvm::ELF::STT_GNU_IFUNC) this->type = llvm::ELF::STT_FUNC; llvm-svn: 371361
2019-09-09 11:35:14 +08:00
/// Note, ld.bfd uses _start as the _entry.
// CHECK: Entry: [[ADDR:[0-9A-F]+]]
// CHECK: Name: __wrap__start
// CHECK-NEXT: Value: [[ADDR]]
Change how we handle -wrap. We have an issue with -wrap that the option doesn't work well when renamed symbols get PLT entries. I'll explain what is the issue and how this patch solves it. For one -wrap option, we have three symbols: foo, wrap_foo and real_foo. Currently, we use memcpy to overwrite wrapped symbols so that they get the same contents. This works in most cases but doesn't when the relocation processor sets some flags in the symbol. memcpy'ed symbols are just aliases, so they always have to have the same contents, but the relocation processor breaks that assumption. r336609 is an attempt to fix the issue by memcpy'ing again after processing relocations, so that symbols that are out of sync get the same contents again. That works in most cases as well, but it breaks ASan build in a mysterious way. We could probably fix the issue by choosing symbol attributes that need to be copied after they are updated. But it feels too complicated to me. So, in this patch, I fixed it once and for all. With this patch, we no longer memcpy symbols. All references to renamed symbols point to new symbols after wrapSymbols() is done. Differential Revision: https://reviews.llvm.org/D50569 llvm-svn: 340387
2018-08-22 15:02:26 +08:00
.global _start, __wrap__start
_start:
nop
__wrap__start:
nop