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[COFF] Improve the autoexport check for symbols from import libraries with -opt:noref 

If -opt:noref is specified, they can end up with isLive() == 1
when the autoexport check is run.

To reduce the risk of potential issues, only consider exporting
DefinedRegular and DefinedCommon, nothing else.

Differential Revision: https://reviews.llvm.org/D40014

llvm-svn: 318384
This commit is contained in:
Martin Storsjo 2017-11-16 07:22:44 +00:00
parent 3920189bcc
commit fe3eda9137
2 changed files with 19 additions and 0 deletions
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8
lld/COFF/MinGW.cpp
View File

@ -91,8 +91,16 @@ AutoExporter::AutoExporter() {
bool AutoExporter::shouldExport(Defined *Sym) const {
if (!Sym || !Sym->isLive() || !Sym->getChunk())
return false;
// Only allow the symbol kinds that make sense to export; in particular,
// disallow import symbols.
if (!isa<DefinedRegular>(Sym) && !isa<DefinedCommon>(Sym))
return false;
if (ExcludeSymbols.count(Sym->getName()))
return false;
// Check that file is non-null before dereferencing it, symbols not
// originating in regular object files probably shouldn't be exported.
if (!Sym->getFile())
return false;
StringRef LibName = sys::path::filename(Sym->getFile()->ParentName);
// Drop the file extension.
LibName = LibName.substr(0, LibName.rfind('.'));

11
lld/test/COFF/export-all.s
View File

@ -65,3 +65,14 @@ _dataSym:
# CHECK-EXCLUDE: EXPORTS
# CHECK-EXCLUDE-NEXT: foobar @1
# CHECK-EXCLUDE-NEXT: EOF
# Test that we handle import libraries together with -opt:noref.
# RUN: yaml2obj < %p/Inputs/hello32.yaml > %t.obj
# RUN: lld-link -lldmingw -dll -out:%t.dll -entry:main@0 %t.obj -implib:%t.lib -opt:noref %p/Inputs/std32.lib -output-def:%t.def
# RUN: echo "EOF" >> %t.def
# RUN: cat %t.def | FileCheck -check-prefix=CHECK-IMPLIB %s
# CHECK-IMPLIB: EXPORTS
# CHECK-IMPLIB-NEXT: main@0 @1
# CHECK-IMPLIB-NEXT: EOF