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COFF: Check for auxiliary symbol's type. 

We forgot to check for auxiliary symbol's type. So we sometimes read
garbage as associative section definitions.

Associative sections are considered as not live themselves by the
garbage collector because they are live only when associaited sections
are live.

By reading more data (or garbage) as associative section definitions,
we treated more sections as non-GC-roots, that caused the linker to
discard too many sections by mistake. That caused another mysterious
bug (such as some global constructors don't run at all for some reason.)

llvm-svn: 239287
This commit is contained in:
Rui Ueyama 2015-06-08 05:00:42 +00:00
parent 056decbfee
commit 80141a4bcd
2 changed files with 9 additions and 5 deletions
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10
lld/COFF/InputFiles.cpp
View File

@ -22,6 +22,7 @@
using namespace llvm::object;
using namespace llvm::support::endian;
using llvm::COFF::ImportHeader;
using llvm::COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE;
using llvm::RoundUpToAlignment;
using llvm::sys::fs::identify_magic;
using llvm::sys::fs::file_magic;
@ -200,13 +201,16 @@ SymbolBody *ObjectFile::createSymbolBody(StringRef Name, COFFSymbolRef Sym,
auto *Aux = (const coff_aux_weak_external *)AuxP;
return new (Alloc) Undefined(Name, &SparseSymbolBodies[Aux->TagIndex]);
}
// Handle associative sections
if (IsFirst && AuxP) {
if (Chunk *C = SparseChunks[Sym.getSectionNumber()]) {
auto *Aux = reinterpret_cast<const coff_aux_section_definition *>(AuxP);
auto *Parent =
if (Aux->Selection == IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
auto *Parent =
(SectionChunk *)(SparseChunks[Aux->getNumber(Sym.isBigObj())]);
if (Parent)
Parent->addAssociative((SectionChunk *)C);
if (Parent)
Parent->addAssociative((SectionChunk *)C);
}
}
}
if (Chunk *C = SparseChunks[Sym.getSectionNumber()])

4
lld/test/COFF/lto.ll
View File

@ -50,7 +50,7 @@
; TEXT-11-NEXT: movl $2, %eax
; TEXT-11-NEXT: retq
; HEADERS-01: AddressOfEntryPoint: 0x1000
; HEADERS-01: AddressOfEntryPoint: 0x2000
; TEXT-01: Disassembly of section .text:
; TEXT-01-NEXT: .text:
; TEXT-01-NEXT: subq $40, %rsp
@ -60,7 +60,7 @@
; TEXT-01-NEXT: retq
; TEXT-01-NEXT: retq
; HEADERS-10: AddressOfEntryPoint: 0x1010
; HEADERS-10: AddressOfEntryPoint: 0x2010
; TEXT-10: Disassembly of section .text:
; TEXT-10-NEXT: .text:
; TEXT-10-NEXT: retq