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[COFF] Handle .eh_frame$symbol as associative comdat for MinGW 

This matches how it is done for .xdata and .pdata already.

On i386, the symbol name in the section name suffix does not contain
the extra underscore prefix.

This is one part of a fix for PR42217.

Differential Revision: https://reviews.llvm.org/D63350

llvm-svn: 363456
This commit is contained in:
Martin Storsjo 2019-06-14 21:02:04 +00:00
parent 9e5fa33378
commit c3b1d730d6
2 changed files with 43 additions and 3 deletions
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9
lld/COFF/InputFiles.cpp
View File

@ -288,6 +288,8 @@ void ObjFile::recordPrevailingSymbolForMingw(
if (SC && SC->getOutputCharacteristics() & IMAGE_SCN_MEM_EXECUTE) {
StringRef Name;
COFFObj->getSymbolName(Sym, Name);
if (getMachineType() == I386)
Name.consume_front("_");
PrevailingSectionMap[Name] = SectionNumber;
}
}
@ -297,9 +299,10 @@ void ObjFile::maybeAssociateSEHForMingw(
const DenseMap<StringRef, uint32_t> &PrevailingSectionMap) {
StringRef Name;
COFFObj->getSymbolName(Sym, Name);
if (Name.consume_front(".pdata$") || Name.consume_front(".xdata$")) {
// For MinGW, treat .[px]data$<func> as implicitly associative to
// the symbol <func>.
if (Name.consume_front(".pdata$") || Name.consume_front(".xdata$") ||
Name.consume_front(".eh_frame$")) {
// For MinGW, treat .[px]data$<func> and .eh_frame$<func> as implicitly
// associative to the symbol <func>.
auto ParentSym = PrevailingSectionMap.find(Name);
if (ParentSym != PrevailingSectionMap.end())
readAssociativeDefinition(Sym, Def, ParentSym->second);

37
lld/test/COFF/associative-comdat-mingw-i386.s Normal file
View File

@ -0,0 +1,37 @@
# REQUIRES: x86
# RUN: llvm-mc -triple=i686-windows-gnu %s -filetype=obj -o %t.obj
# RUN: lld-link -lldmingw -entry:main %t.obj -out:%t.exe
# RUN: llvm-objdump -s %t.exe | FileCheck %s
# Check that the .eh_frame comdat was included, even if it had no symbols,
# due to associativity with the symbol _foo.
# CHECK: Contents of section .eh_fram:
# CHECK: 403000 42
.text
.def _main;
.scl 2;
.type 32;
.endef
.globl _main
.p2align 4, 0x90
_main:
call _foo
ret
.section .eh_frame$foo,"dr"
.linkonce discard
.byte 0x42
.def _foo;
.scl 2;
.type 32;
.endef
.section .text$foo,"xr",discard,foo
.globl _foo
.p2align 4
_foo:
ret