Author: Martin Storsjö Date: 2020-07-27T13:10:48+02:00 New Revision: f3a043717d265105ab854c5f84ec03c2f67d9a63
URL: https://github.com/llvm/llvm-project/commit/f3a043717d265105ab854c5f84ec03c2f67d9a63 DIFF: https://github.com/llvm/llvm-project/commit/f3a043717d265105ab854c5f84ec03c2f67d9a63.diff LOG: [MC] [COFF] Make sure that weak external symbols are undefined symbols For comdats (e.g. caused by -ffunction-sections), Section is already set here; make sure it's null, for the weak external symbol to be undefined. This fixes PR46779. Differential Revision: https://reviews.llvm.org/D84507 (cherry picked from commit 9e81d8bbf19d72fca3d87b7334c613d1aa2a5795) Added: llvm/test/MC/COFF/weak-comdat.s Modified: llvm/lib/MC/WinCOFFObjectWriter.cpp Removed: ################################################################################ diff --git a/llvm/lib/MC/WinCOFFObjectWriter.cpp b/llvm/lib/MC/WinCOFFObjectWriter.cpp index 4796ef531054..8e7bf1eb0169 100644 --- a/llvm/lib/MC/WinCOFFObjectWriter.cpp +++ b/llvm/lib/MC/WinCOFFObjectWriter.cpp @@ -375,6 +375,7 @@ void WinCOFFObjectWriter::DefineSymbol(const MCSymbol &MCSym, COFFSymbol *Local = nullptr; if (cast<MCSymbolCOFF>(MCSym).isWeakExternal()) { Sym->Data.StorageClass = COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL; + Sym->Section = nullptr; COFFSymbol *WeakDefault = getLinkedSymbol(MCSym); if (!WeakDefault) { diff --git a/llvm/test/MC/COFF/weak-comdat.s b/llvm/test/MC/COFF/weak-comdat.s new file mode 100644 index 000000000000..8605da6b521d --- /dev/null +++ b/llvm/test/MC/COFF/weak-comdat.s @@ -0,0 +1,34 @@ +// RUN: llvm-mc -filetype=obj -triple x86_64-pc-win32 %s -o %t.o +// RUN: llvm-readobj --symbols %t.o | FileCheck %s + +// Test that the weak symbol is properly undefined, while originally being +// the leader symbol for a comdat. (This can easily happen if building with +// -ffunction-sections). + + .section .text$func,"xr",one_only,func + .weak func +func: + ret + +// CHECK: Symbol { +// CHECK: Name: func +// CHECK-NEXT: Value: 0 +// CHECK-NEXT: Section: IMAGE_SYM_UNDEFINED (0) +// CHECK-NEXT: BaseType: Null (0x0) +// CHECK-NEXT: ComplexType: Null (0x0) +// CHECK-NEXT: StorageClass: WeakExternal (0x69) +// CHECK-NEXT: AuxSymbolCount: 1 +// CHECK-NEXT: AuxWeakExternal { +// CHECK-NEXT: Linked: .weak.func.default (10) +// CHECK-NEXT: Search: Alias (0x3) +// CHECK-NEXT: } +// CHECK-NEXT: } +// CHECK-NEXT: Symbol { +// CHECK-NEXT: Name: .weak.func.default +// CHECK-NEXT: Value: 0 +// CHECK-NEXT: Section: .text$func (4) +// CHECK-NEXT: BaseType: Null (0x0) +// CHECK-NEXT: ComplexType: Null (0x0) +// CHECK-NEXT: StorageClass: External (0x2) +// CHECK-NEXT: AuxSymbolCount: 0 +// CHECK-NEXT: } _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
