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COFF: Read linker directives from bitcode files.
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Differential Revision: http://reviews.llvm.org/D10285

llvm-svn: 239212
pcc committed Jun 6, 2015
1 parent 1781a68 commit ace2f09
Showing 5 changed files with 48 additions and 11 deletions.
17 changes: 17 additions & 0 deletions lld/COFF/InputFiles.cpp
Original file line number Diff line number Diff line change
@@ -263,6 +263,23 @@ std::error_code BitcodeFile::parse() {
SymbolBodies.push_back(new (Alloc) DefinedBitcode(SymName));
}
}

// Extract any linker directives from the bitcode file, which are represented
// as module flags with the key "Linker Options".
llvm::SmallVector<llvm::Module::ModuleFlagEntry, 8> Flags;
M->getModule().getModuleFlagsMetadata(Flags);
for (auto &&Flag : Flags) {
if (Flag.Key->getString() != "Linker Options")
continue;

for (llvm::Metadata *Op : cast<llvm::MDNode>(Flag.Val)->operands()) {
for (llvm::Metadata *InnerOp : cast<llvm::MDNode>(Op)->operands()) {
Directives += " ";
Directives += cast<llvm::MDString>(InnerOp)->getString();
}
}
}

return std::error_code();
}

4 changes: 4 additions & 0 deletions lld/COFF/InputFiles.h
Original file line number Diff line number Diff line change
@@ -170,13 +170,17 @@ class BitcodeFile : public InputFile {
LTOModule *getModule() const { return M.get(); }
LTOModule *releaseModule() { return M.release(); }

// Returns linker directives from module flags metadata if present.
StringRef getDirectives() { return Directives; }

private:
std::error_code parse() override;

MemoryBufferRef MB;
std::vector<SymbolBody *> SymbolBodies;
llvm::BumpPtrAllocator Alloc;
std::unique_ptr<LTOModule> M;
std::string Directives;
};

} // namespace coff
25 changes: 14 additions & 11 deletions lld/COFF/SymbolTable.cpp
Original file line number Diff line number Diff line change
@@ -40,6 +40,17 @@ std::error_code SymbolTable::addFile(std::unique_ptr<InputFile> File) {
return addImport(cast<ImportFile>(FileP));
}

std::error_code SymbolTable::addDirectives(StringRef Dir) {
if (Dir.empty())
return std::error_code();
std::vector<std::unique_ptr<InputFile>> Libs;
if (auto EC = Driver->parseDirectives(Dir, &Libs))
return EC;
for (std::unique_ptr<InputFile> &Lib : Libs)
addFile(std::move(Lib));
return std::error_code();
}

std::error_code SymbolTable::addObject(ObjectFile *File) {
ObjectFiles.emplace_back(File);
for (SymbolBody *Body : File->getSymbols())
@@ -49,15 +60,7 @@ std::error_code SymbolTable::addObject(ObjectFile *File) {

// If an object file contains .drectve section, read it and add
// files listed in the section.
StringRef Dir = File->getDirectives();
if (!Dir.empty()) {
std::vector<std::unique_ptr<InputFile>> Libs;
if (auto EC = Driver->parseDirectives(Dir, &Libs))
return EC;
for (std::unique_ptr<InputFile> &Lib : Libs)
addFile(std::move(Lib));
}
return std::error_code();
return addDirectives(File->getDirectives());
}

std::error_code SymbolTable::addArchive(ArchiveFile *File) {
@@ -75,8 +78,8 @@ std::error_code SymbolTable::addBitcode(BitcodeFile *File) {
if (auto EC = resolve(Body))
return EC;

// TODO: Handle linker directives.
return std::error_code();
// Add any linker directives from the module flags metadata.
return addDirectives(File->getDirectives());
}

std::error_code SymbolTable::addImport(ImportFile *File) {
2 changes: 2 additions & 0 deletions lld/COFF/SymbolTable.h
Original file line number Diff line number Diff line change
@@ -77,6 +77,8 @@ class SymbolTable {
std::error_code rename(StringRef From, StringRef To);

private:
std::error_code addDirectives(StringRef Dir);

std::error_code addObject(ObjectFile *File);
std::error_code addArchive(ArchiveFile *File);
std::error_code addImport(ImportFile *File);
11 changes: 11 additions & 0 deletions lld/test/COFF/lto-linker-opts.ll
Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
; RUN: llvm-as -o %T/lto-linker-opts.obj %s
; RUN: env LIB=%S/Inputs lld -flavor link2 /out:%T/lto-linker-opts.exe /entry:main /subsystem:console %T/lto-linker-opts.obj

target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc"

!llvm.module.flags = !{!0}

!0 = !{i32 6, !"Linker Options", !1}
!1 = !{!2}
!2 = !{!"/DEFAULTLIB:ret42.lib"}

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