llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-lld Author: DianQK (DianQK) <details> <summary>Changes</summary> Backport #<!-- -->111945. (cherry picked from commit 1c6688ae3449da9c8fee1e1c12c892223496fb4c) --- Full diff: https://github.com/llvm/llvm-project/pull/112136.diff 2 Files Affected: - (modified) lld/ELF/LinkerScript.cpp (+8-1) - (added) lld/test/ELF/linkerscript/provide-defined.s (+36) ``````````diff diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp index 055fa21d44ca6e..d95c5573935ec4 100644 --- a/lld/ELF/LinkerScript.cpp +++ b/lld/ELF/LinkerScript.cpp @@ -1718,6 +1718,13 @@ void LinkerScript::addScriptReferencedSymbolsToSymTable() { } bool LinkerScript::shouldAddProvideSym(StringRef symName) { + // This function is called before and after garbage collection. To prevent + // undefined references from the RHS, the result of this function for a + // symbol must be the same for each call. We use isUsedInRegularObj to not + // change the return value of a demoted symbol. The exportDynamic condition, + // while not so accurate, allows PROVIDE to define a symbol referenced by a + // DSO. Symbol *sym = symtab.find(symName); - return sym && !sym->isDefined() && !sym->isCommon(); + return sym && !sym->isDefined() && !sym->isCommon() && + (sym->isUsedInRegularObj || sym->exportDynamic); } diff --git a/lld/test/ELF/linkerscript/provide-defined.s b/lld/test/ELF/linkerscript/provide-defined.s new file mode 100644 index 00000000000000..1d44bef3d4068d --- /dev/null +++ b/lld/test/ELF/linkerscript/provide-defined.s @@ -0,0 +1,36 @@ +# REQUIRES: x86 +## Test the GC behavior when the PROVIDE symbol is defined by a relocatable file. + +# RUN: rm -rf %t && split-file %s %t && cd %t +# RUN: llvm-mc -filetype=obj -triple=x86_64 a.s -o a.o +# RUN: llvm-mc -filetype=obj -triple=x86_64 b.s -o b.o +# RUN: ld.lld -T a.t --gc-sections a.o b.o -o a +# RUN: llvm-readelf -s a | FileCheck %s + +# CHECK: 1: {{.*}} 0 NOTYPE GLOBAL DEFAULT 1 _start +# CHECK-NEXT:2: {{.*}} 0 NOTYPE GLOBAL DEFAULT 2 f3 +# CHECK-NOT: {{.}} + +#--- a.s +.global _start, f1, f2, f3, bar +_start: + call f3 + +.section .text.f1,"ax"; f1: +.section .text.f2,"ax"; f2: # referenced by another relocatable file +.section .text.f3,"ax"; f3: # live +.section .text.bar,"ax"; bar: + +.comm comm,4,4 + +#--- b.s + call f2 + +#--- a.t +SECTIONS { + . = . + SIZEOF_HEADERS; + PROVIDE(f1 = bar+1); + PROVIDE(f2 = bar+2); + PROVIDE(f3 = bar+3); + PROVIDE(f4 = comm+4); +} `````````` </details> https://github.com/llvm/llvm-project/pull/112136 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
