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COFF: Move machine type auto-detection to SymbolTable.

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The new mechanism is less code, and fixes the case where all inputs
are archives.

Differential Revision: http://reviews.llvm.org/D10136

llvm-svn: 238618
This commit is contained in:
Peter Collingbourne 2015-05-29 21:47:36 +00:00
parent 4d37b2a259
commit 246ccc5f51
5 changed files with 29 additions and 27 deletions
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25
lld/COFF/DriverUtils.cpp
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@ -87,24 +87,6 @@ std::string findFile(StringRef Filename) {
return Filename;
}
// Peeks at the file header to get architecture (e.g. i386 or AMD64).
// Returns "unknown" if it's not a valid object file.
static MachineTypes getFileMachineType(StringRef Path) {
file_magic Magic;
if (identify_magic(Path, Magic))
return IMAGE_FILE_MACHINE_UNKNOWN;
if (Magic != file_magic::coff_object)
return IMAGE_FILE_MACHINE_UNKNOWN;
ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr = MemoryBuffer::getFile(Path);
if (BufOrErr.getError())
return IMAGE_FILE_MACHINE_UNKNOWN;
std::error_code EC;
llvm::object::COFFObjectFile Obj(BufOrErr.get()->getMemBufferRef(), EC);
if (EC)
return IMAGE_FILE_MACHINE_UNKNOWN;
return static_cast<MachineTypes>(Obj.getMachine());
}
// Returns /machine's value.
ErrorOr<MachineTypes> getMachineType(llvm::opt::InputArgList *Args) {
if (auto *Arg = Args->getLastArg(OPT_machine)) {
@ -118,13 +100,6 @@ ErrorOr<MachineTypes> getMachineType(llvm::opt::InputArgList *Args) {
return make_dynamic_error_code("unknown /machine argument" + S);
return MT;
}
// If /machine option is missing, we need to take a look at
// the magic byte of the first object file to infer machine type.
for (auto *Arg : Args->filtered(OPT_INPUT)) {
MachineTypes MT = getFileMachineType(Arg->getValue());
if (MT != IMAGE_FILE_MACHINE_UNKNOWN)
return MT;
}
return IMAGE_FILE_MACHINE_UNKNOWN;
}

4
lld/COFF/SymbolTable.h
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@ -53,6 +53,9 @@ public:
// order to create the import descriptor table.
std::vector<std::unique_ptr<ImportFile>> ImportFiles;
// The writer needs to infer the machine type from the object files.
std::vector<std::unique_ptr<ObjectFile>> ObjectFiles;
private:
std::error_code addObject(ObjectFile *File);
std::error_code addArchive(ArchiveFile *File);
@ -63,7 +66,6 @@ private:
void addInitialSymbol(SymbolBody *Body);
std::unordered_map<StringRef, Symbol *> Symtab;
std::vector<std::unique_ptr<ObjectFile>> ObjectFiles;
std::vector<std::unique_ptr<ArchiveFile>> ArchiveFiles;
std::vector<std::unique_ptr<SymbolBody>> OwnedSymbols;
llvm::BumpPtrAllocator Alloc;

18
lld/COFF/Writer.cpp
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@ -227,6 +227,17 @@ void Writer::assignAddresses() {
RoundUpToAlignment(FileOff - SizeOfHeaders, FileAlignment);
}
static MachineTypes
inferMachineType(std::vector<std::unique_ptr<ObjectFile>> &ObjectFiles) {
for (std::unique_ptr<ObjectFile> &File : ObjectFiles) {
// Try to infer machine type from the magic byte of the object file.
auto MT = static_cast<MachineTypes>(File->getCOFFObj()->getMachine());
if (MT != IMAGE_FILE_MACHINE_UNKNOWN)
return MT;
}
return IMAGE_FILE_MACHINE_UNKNOWN;
}
void Writer::writeHeader() {
// Write DOS stub
uint8_t *Buf = Buffer->getBufferStart();
@ -241,10 +252,15 @@ void Writer::writeHeader() {
memcpy(Buf, PEMagic, sizeof(PEMagic));
Buf += sizeof(PEMagic);
// Determine machine type, infer if needed. TODO: diagnose conflicts.
MachineTypes MachineType = Config->MachineType;
if (MachineType == IMAGE_FILE_MACHINE_UNKNOWN)
MachineType = inferMachineType(Symtab->ObjectFiles);
// Write COFF header
auto *COFF = reinterpret_cast<coff_file_header *>(Buf);
Buf += sizeof(*COFF);
COFF->Machine = Config->MachineType;
COFF->Machine = MachineType;
COFF->NumberOfSections = OutputSections.size();
COFF->Characteristics =
(IMAGE_FILE_EXECUTABLE_IMAGE | IMAGE_FILE_RELOCS_STRIPPED |

BIN
lld/test/COFF/Inputs/ret42.lib Normal file
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Binary file not shown.

9
lld/test/COFF/machine.test
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@ -1,6 +1,15 @@
# RUN: lld -flavor link2 /entry:main /machine:x64 /out:%t.exe \
# RUN: %p/Inputs/ret42.obj
# RUN: llvm-readobj -file-headers %t.exe | FileCheck -check-prefix=AMD64 %s
# RUN: lld -flavor link2 /entry:main /machine:x64 /out:%t.exe \
# RUN: %p/Inputs/ret42.lib
# RUN: llvm-readobj -file-headers %t.exe | FileCheck -check-prefix=AMD64 %s
# RUN: lld -flavor link2 /entry:main /out:%t.exe \
# RUN: %p/Inputs/ret42.obj
# RUN: llvm-readobj -file-headers %t.exe | FileCheck -check-prefix=AMD64 %s
# RUN: lld -flavor link2 /entry:main /out:%t.exe \
# RUN: %p/Inputs/ret42.lib
# RUN: llvm-readobj -file-headers %t.exe | FileCheck -check-prefix=AMD64 %s
AMD64: Machine: IMAGE_FILE_MACHINE_AMD64