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author | Martin Storsjö <martin@martin.st> | 2020-07-21 23:39:37 +0300 |
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committer | Hans Wennborg <hans@chromium.org> | 2020-07-27 13:10:48 +0200 |
commit | f3a043717d265105ab854c5f84ec03c2f67d9a63 (patch) | |
tree | 17cfc9dfa124d093e9aa4c2f0e58db79682ea17a | |
parent | 1daf1144ad1ea302d3a5f208c450da7774b4b607 (diff) | |
download | llvm-f3a043717d265105ab854c5f84ec03c2f67d9a63.zip llvm-f3a043717d265105ab854c5f84ec03c2f67d9a63.tar.gz llvm-f3a043717d265105ab854c5f84ec03c2f67d9a63.tar.bz2 |
[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)
-rw-r--r-- | llvm/lib/MC/WinCOFFObjectWriter.cpp | 1 | ||||
-rw-r--r-- | llvm/test/MC/COFF/weak-comdat.s | 34 |
2 files changed, 35 insertions, 0 deletions
diff --git a/llvm/lib/MC/WinCOFFObjectWriter.cpp b/llvm/lib/MC/WinCOFFObjectWriter.cpp index 4796ef5..8e7bf1e 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 0000000..8605da6 --- /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: } |