[lld] r217189 - [mach-o] Let darwin driver infer arch from .o files if -arch not used.
Nick Kledzik
kledzik at apple.com
Thu Sep 4 14:40:37 PDT 2014
On Sep 4, 2014, at 2:17 PM, Shankar Easwaran <shankare at codeaurora.org> wrote:
> Nice!
>
> Is this applicable in partial linking mode ?
>
> What if the first file was an archive file or a script (that could contain more inputs) ?
It looks at each file in command line order until if finds a non-fat MH_OBJECT mach-o file. If none are found, it errors out that -arch is needed.
> I think its better to get the first file from the input graph and query for the arch type ?
The input graph is not built until the end of the command line parsing, but the arch is needed early because it can effect how other options are processed.
I’m not worried about performance.
-Nick
>
> On 9/4/2014 3:08 PM, Nick Kledzik wrote:
>> Author: kledzik
>> Date: Thu Sep 4 15:08:30 2014
>> New Revision: 217189
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=217189&view=rev
>> Log:
>> [mach-o] Let darwin driver infer arch from .o files if -arch not used.
>>
>> Mach-O has a "fat" (or "universal") variant where the same contents built for
>> different architectures are concatenated into one file with a table-of-contents
>> header at the start. But this leaves a dilemma for the linker - which
>> architecture to use.
>>
>> Normally, the linker command line -arch is used to force which slice of any fat
>> files are used. The clang compiler always passes -arch to the linker when
>> invoking it. But some Makefiles invoke the linker directly and don’t specify
>> the -arch option. For those cases, the linker scans all input files in command
>> line order and finds the first non-fat object file. Whatever architecture it
>> is becomes the architecture for the link.
>>
>> Added:
>> lld/trunk/test/mach-o/infer-arch.yaml
>> Modified:
>> lld/trunk/include/lld/ReaderWriter/MachOLinkingContext.h
>> lld/trunk/lib/Driver/DarwinLdDriver.cpp
>> lld/trunk/lib/ReaderWriter/MachO/MachOLinkingContext.cpp
>> lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h
>> lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryReader.cpp
>> lld/trunk/unittests/DriverTests/DarwinLdDriverTest.cpp
>>
>> Modified: lld/trunk/include/lld/ReaderWriter/MachOLinkingContext.h
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/include/lld/ReaderWriter/MachOLinkingContext.h?rev=217189&r1=217188&r2=217189&view=diff
>> ==============================================================================
>> --- lld/trunk/include/lld/ReaderWriter/MachOLinkingContext.h (original)
>> +++ lld/trunk/include/lld/ReaderWriter/MachOLinkingContext.h Thu Sep 4 15:08:30 2014
>> @@ -222,6 +222,7 @@ public:
>> /// Creates a copy (owned by this MachOLinkingContext) of a string.
>> StringRef copy(StringRef str) { return str.copy(_allocator); }
>> + static bool isThinObjectFile(StringRef path, Arch &arch);
>> static Arch archFromCpuType(uint32_t cputype, uint32_t cpusubtype);
>> static Arch archFromName(StringRef archName);
>> static StringRef nameFromArch(Arch arch);
>>
>> Modified: lld/trunk/lib/Driver/DarwinLdDriver.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/Driver/DarwinLdDriver.cpp?rev=217189&r1=217188&r2=217189&view=diff
>> ==============================================================================
>> --- lld/trunk/lib/Driver/DarwinLdDriver.cpp (original)
>> +++ lld/trunk/lib/Driver/DarwinLdDriver.cpp Thu Sep 4 15:08:30 2014
>> @@ -243,6 +243,20 @@ bool DarwinLdDriver::parse(int argc, con
>> return false;
>> }
>> }
>> + // If no -arch specified, scan input files to find first non-fat .o file.
>> + if ((arch == MachOLinkingContext::arch_unknown)
>> + && !parsedArgs->getLastArg(OPT_test_file_usage)) {
>> + for (auto &inFile: parsedArgs->filtered(OPT_INPUT)) {
>> + // This is expensive because it opens and maps the file. But that is
>> + // ok because no -arch is rare.
>> + if (MachOLinkingContext::isThinObjectFile(inFile->getValue(), arch))
>> + break;
>> + }
>> + if (arch == MachOLinkingContext::arch_unknown) {
>> + diagnostics << "error: -arch not specified and could not be inferred\n";
>> + return false;
>> + }
>> + }
>> // Handle -macosx_version_min or -ios_version_min
>> MachOLinkingContext::OS os = MachOLinkingContext::OS::macOSX;
>>
>> Modified: lld/trunk/lib/ReaderWriter/MachO/MachOLinkingContext.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachOLinkingContext.cpp?rev=217189&r1=217188&r2=217189&view=diff
>> ==============================================================================
>> --- lld/trunk/lib/ReaderWriter/MachO/MachOLinkingContext.cpp (original)
>> +++ lld/trunk/lib/ReaderWriter/MachO/MachOLinkingContext.cpp Thu Sep 4 15:08:30 2014
>> @@ -11,6 +11,7 @@
>> #include "ArchHandler.h"
>> #include "File.h"
>> +#include "MachONormalizedFile.h"
>> #include "MachOPasses.h"
>> #include "lld/Core/PassManager.h"
>> @@ -125,6 +126,10 @@ uint32_t MachOLinkingContext::cpuSubtype
>> llvm_unreachable("Unknown arch type");
>> }
>> +bool MachOLinkingContext::isThinObjectFile(StringRef path, Arch &arch) {
>> + return mach_o::normalized::isThinObjectFile(path, arch);
>> +}
>> +
>> MachOLinkingContext::MachOLinkingContext()
>> : _outputMachOType(MH_EXECUTE), _outputMachOTypeStatic(false),
>> _doNothing(false), _arch(arch_unknown), _os(OS::macOSX), _osMinVersion(0),
>>
>> Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h?rev=217189&r1=217188&r2=217189&view=diff
>> ==============================================================================
>> --- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h (original)
>> +++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h Thu Sep 4 15:08:30 2014
>> @@ -252,6 +252,8 @@ struct NormalizedFile {
>> BumpPtrAllocator ownedAllocations;
>> };
>> +/// Tests if a file is a non-fat mach-o object file.
>> +bool isThinObjectFile(StringRef path, MachOLinkingContext::Arch &arch);
>> /// Reads a mach-o file and produces an in-memory normalized view.
>> ErrorOr<std::unique_ptr<NormalizedFile>>
>>
>> Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryReader.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryReader.cpp?rev=217189&r1=217188&r2=217189&view=diff
>> ==============================================================================
>> --- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryReader.cpp (original)
>> +++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryReader.cpp Thu Sep 4 15:08:30 2014
>> @@ -117,6 +117,59 @@ template <typename T> static T readBigEn
>> return t;
>> }
>> +
>> +static bool isMachOHeader(const mach_header *mh, bool &is64, bool &swap) {
>> + switch (mh->magic) {
>> + case llvm::MachO::MH_MAGIC:
>> + is64 = false;
>> + swap = false;
>> + return true;
>> + case llvm::MachO::MH_MAGIC_64:
>> + is64 = true;
>> + swap = false;
>> + return true;
>> + case llvm::MachO::MH_CIGAM:
>> + is64 = false;
>> + swap = true;
>> + return true;
>> + case llvm::MachO::MH_CIGAM_64:
>> + is64 = true;
>> + swap = true;
>> + return true;
>> + default:
>> + return false;
>> + }
>> +}
>> +
>> +
>> +bool isThinObjectFile(StringRef path, MachOLinkingContext::Arch &arch) {
>> + // Try opening and mapping file at path.
>> + ErrorOr<std::unique_ptr<MemoryBuffer>> b = MemoryBuffer::getFileOrSTDIN(path);
>> + if (b.getError())
>> + return false;
>> +
>> + // If file length < 32 it is too small to be mach-o object file.
>> + StringRef fileBuffer = b->get()->getBuffer();
>> + if (fileBuffer.size() < 32)
>> + return false;
>> +
>> + // If file buffer does not start with MH_MAGIC (and variants), not obj file.
>> + const mach_header *mh = reinterpret_cast<const mach_header *>(
>> + fileBuffer.begin());
>> + bool is64, swap;
>> + if (!isMachOHeader(mh, is64, swap))
>> + return false;
>> +
>> + // If not MH_OBJECT, not object file.
>> + if (read32(swap, mh->filetype) != MH_OBJECT)
>> + return false;
>> +
>> + // Lookup up arch from cpu/subtype pair.
>> + arch = MachOLinkingContext::archFromCpuType(read32(swap, mh->cputype),
>> + read32(swap, mh->cpusubtype));
>> + return true;
>> +}
>> +
>> /// Reads a mach-o file and produces an in-memory normalized view.
>> ErrorOr<std::unique_ptr<NormalizedFile>>
>> readBinary(std::unique_ptr<MemoryBuffer> &mb,
>> @@ -162,26 +215,8 @@ readBinary(std::unique_ptr<MemoryBuffer>
>> }
>> bool is64, swap;
>> - switch (mh->magic) {
>> - case llvm::MachO::MH_MAGIC:
>> - is64 = false;
>> - swap = false;
>> - break;
>> - case llvm::MachO::MH_MAGIC_64:
>> - is64 = true;
>> - swap = false;
>> - break;
>> - case llvm::MachO::MH_CIGAM:
>> - is64 = false;
>> - swap = true;
>> - break;
>> - case llvm::MachO::MH_CIGAM_64:
>> - is64 = true;
>> - swap = true;
>> - break;
>> - default:
>> + if (!isMachOHeader(mh, is64, swap))
>> return make_error_code(llvm::errc::executable_format_error);
>> - }
>> // Endian swap header, if needed.
>> mach_header headerCopy;
>>
>> Added: lld/trunk/test/mach-o/infer-arch.yaml
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/mach-o/infer-arch.yaml?rev=217189&view=auto
>> ==============================================================================
>> --- lld/trunk/test/mach-o/infer-arch.yaml (added)
>> +++ lld/trunk/test/mach-o/infer-arch.yaml Thu Sep 4 15:08:30 2014
>> @@ -0,0 +1,29 @@
>> +# RUN: lld -flavor darwin -arch i386 -macosx_version_min 10.8 %s -r -o %t \
>> +# RUN: && lld -flavor darwin -r %t -o %t2 -print_atoms | FileCheck %s
>> +#
>> +# Test linker can detect architecture without -arch option.
>> +#
>> +
>> +--- !mach-o
>> +arch: x86
>> +file-type: MH_OBJECT
>> +flags: [ MH_SUBSECTIONS_VIA_SYMBOLS ]
>> +sections:
>> + - segment: __TEXT
>> + section: __text
>> + type: S_REGULAR
>> + attributes: [ S_ATTR_PURE_INSTRUCTIONS, S_ATTR_SOME_INSTRUCTIONS ]
>> + address: 0x0000000000000000
>> + content: [ 0xC3 ]
>> +global-symbols:
>> + - name: _foo
>> + type: N_SECT
>> + scope: [ N_EXT ]
>> + sect: 1
>> + value: 0x0000000000000000
>> +
>> +...
>> +
>> +
>> +# CHECK: defined-atoms:
>> +# CHECK: - name: _foo
>>
>> Modified: lld/trunk/unittests/DriverTests/DarwinLdDriverTest.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/unittests/DriverTests/DarwinLdDriverTest.cpp?rev=217189&r1=217188&r2=217189&view=diff
>> ==============================================================================
>> --- lld/trunk/unittests/DriverTests/DarwinLdDriverTest.cpp (original)
>> +++ lld/trunk/unittests/DriverTests/DarwinLdDriverTest.cpp Thu Sep 4 15:08:30 2014
>> @@ -30,7 +30,7 @@ protected:
>> }
>> TEST_F(DarwinLdParserTest, Basic) {
>> - EXPECT_TRUE(parse("ld", "foo.o", "bar.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "foo.o", "bar.o", "-arch", "i386", nullptr));
>> EXPECT_FALSE(_context.allowRemainingUndefines());
>> EXPECT_FALSE(_context.deadStrip());
>> EXPECT_EQ(2, inputFileCount());
>> @@ -39,45 +39,40 @@ TEST_F(DarwinLdParserTest, Basic) {
>> }
>> TEST_F(DarwinLdParserTest, Output) {
>> - EXPECT_TRUE(parse("ld", "-o", "my.out", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-o", "my.out", "foo.o", "-arch", "i386", nullptr));
>> EXPECT_EQ("my.out", _context.outputPath());
>> }
>> TEST_F(DarwinLdParserTest, Dylib) {
>> - EXPECT_TRUE(parse("ld", "-dylib", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-dylib", "foo.o", "-arch", "i386", nullptr));
>> EXPECT_EQ(llvm::MachO::MH_DYLIB, _context.outputMachOType());
>> }
>> TEST_F(DarwinLdParserTest, Relocatable) {
>> - EXPECT_TRUE(parse("ld", "-r", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-r", "foo.o", "-arch", "i386", nullptr));
>> EXPECT_EQ(llvm::MachO::MH_OBJECT, _context.outputMachOType());
>> }
>> TEST_F(DarwinLdParserTest, Bundle) {
>> - EXPECT_TRUE(parse("ld", "-bundle", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-bundle", "foo.o", "-arch", "i386", nullptr));
>> EXPECT_EQ(llvm::MachO::MH_BUNDLE, _context.outputMachOType());
>> }
>> TEST_F(DarwinLdParserTest, Preload) {
>> - EXPECT_TRUE(parse("ld", "-preload", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-preload", "foo.o", "-arch", "i386", nullptr));
>> EXPECT_EQ(llvm::MachO::MH_PRELOAD, _context.outputMachOType());
>> }
>> TEST_F(DarwinLdParserTest, Static) {
>> - EXPECT_TRUE(parse("ld", "-static", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-static", "foo.o", "-arch", "i386", nullptr));
>> EXPECT_EQ(llvm::MachO::MH_EXECUTE, _context.outputMachOType());
>> }
>> TEST_F(DarwinLdParserTest, Entry) {
>> - EXPECT_TRUE(parse("ld", "-e", "entryFunc", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-e", "entryFunc", "foo.o", "-arch", "i386",nullptr));
>> EXPECT_EQ("entryFunc", _context.entrySymbolName());
>> }
>> -TEST_F(DarwinLdParserTest, OutputPath) {
>> - EXPECT_TRUE(parse("ld", "-o", "foo", "foo.o", nullptr));
>> - EXPECT_EQ("foo", _context.outputPath());
>> -}
>> -
>> TEST_F(DarwinLdParserTest, DeadStrip) {
>> EXPECT_TRUE(parse("ld", "-arch", "x86_64", "-dead_strip", "foo.o", nullptr));
>> EXPECT_TRUE(_context.deadStrip());
>> @@ -130,42 +125,48 @@ TEST_F(DarwinLdParserTest, Arch_armv7s)
>> }
>> TEST_F(DarwinLdParserTest, MinMacOSX10_7) {
>> - EXPECT_TRUE(parse("ld", "-macosx_version_min", "10.7", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-macosx_version_min", "10.7", "foo.o",
>> + "-arch", "x86_64", nullptr));
>> EXPECT_EQ(MachOLinkingContext::OS::macOSX, _context.os());
>> EXPECT_TRUE(_context.minOS("10.7", ""));
>> EXPECT_FALSE(_context.minOS("10.8", ""));
>> }
>> TEST_F(DarwinLdParserTest, MinMacOSX10_8) {
>> - EXPECT_TRUE(parse("ld", "-macosx_version_min", "10.8.3", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-macosx_version_min", "10.8.3", "foo.o",
>> + "-arch", "x86_64", nullptr));
>> EXPECT_EQ(MachOLinkingContext::OS::macOSX, _context.os());
>> EXPECT_TRUE(_context.minOS("10.7", ""));
>> EXPECT_TRUE(_context.minOS("10.8", ""));
>> }
>> TEST_F(DarwinLdParserTest, iOS5) {
>> - EXPECT_TRUE(parse("ld", "-ios_version_min", "5.0", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-ios_version_min", "5.0", "foo.o",
>> + "-arch", "armv7", nullptr));
>> EXPECT_EQ(MachOLinkingContext::OS::iOS, _context.os());
>> EXPECT_TRUE(_context.minOS("", "5.0"));
>> EXPECT_FALSE(_context.minOS("", "6.0"));
>> }
>> TEST_F(DarwinLdParserTest, iOS6) {
>> - EXPECT_TRUE(parse("ld", "-ios_version_min", "6.0", "foo.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-ios_version_min", "6.0", "foo.o", "-arch", "armv7",
>> + nullptr));
>> EXPECT_EQ(MachOLinkingContext::OS::iOS, _context.os());
>> EXPECT_TRUE(_context.minOS("", "5.0"));
>> EXPECT_TRUE(_context.minOS("", "6.0"));
>> }
>> TEST_F(DarwinLdParserTest, iOS_Simulator5) {
>> - EXPECT_TRUE(parse("ld", "-ios_simulator_version_min", "5.0", "a.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-ios_simulator_version_min", "5.0", "a.o",
>> + "-arch", "i386", nullptr));
>> EXPECT_EQ(MachOLinkingContext::OS::iOS_simulator, _context.os());
>> EXPECT_TRUE(_context.minOS("", "5.0"));
>> EXPECT_FALSE(_context.minOS("", "6.0"));
>> }
>> TEST_F(DarwinLdParserTest, iOS_Simulator6) {
>> - EXPECT_TRUE(parse("ld", "-ios_simulator_version_min", "6.0", "a.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-ios_simulator_version_min", "6.0", "a.o",
>> + "-arch", "i386", nullptr));
>> EXPECT_EQ(MachOLinkingContext::OS::iOS_simulator, _context.os());
>> EXPECT_TRUE(_context.minOS("", "5.0"));
>> EXPECT_TRUE(_context.minOS("", "6.0"));
>> @@ -173,58 +174,67 @@ TEST_F(DarwinLdParserTest, iOS_Simulator
>> TEST_F(DarwinLdParserTest, compatibilityVersion) {
>> EXPECT_TRUE(
>> - parse("ld", "-dylib", "-compatibility_version", "1.2.3", "a.o", nullptr));
>> + parse("ld", "-dylib", "-compatibility_version", "1.2.3", "a.o",
>> + "-arch", "i386",nullptr));
>> EXPECT_EQ(_context.compatibilityVersion(), 0x10203U);
>> }
>> TEST_F(DarwinLdParserTest, compatibilityVersionInvalidType) {
>> EXPECT_FALSE(parse("ld", "-bundle", "-compatibility_version", "1.2.3", "a.o",
>> - nullptr));
>> + "-arch", "i386",nullptr));
>> }
>> TEST_F(DarwinLdParserTest, compatibilityVersionInvalidValue) {
>> EXPECT_FALSE(parse("ld", "-bundle", "-compatibility_version", "1,2,3", "a.o",
>> - nullptr));
>> + "-arch", "i386", nullptr));
>> }
>> TEST_F(DarwinLdParserTest, currentVersion) {
>> EXPECT_TRUE(
>> - parse("ld", "-dylib", "-current_version", "1.2.3", "a.o", nullptr));
>> + parse("ld", "-dylib", "-current_version", "1.2.3", "a.o", "-arch", "i386",
>> + nullptr));
>> EXPECT_EQ(_context.currentVersion(), 0x10203U);
>> }
>> TEST_F(DarwinLdParserTest, currentVersionInvalidType) {
>> EXPECT_FALSE(
>> - parse("ld", "-bundle", "-current_version", "1.2.3", "a.o", nullptr));
>> + parse("ld", "-bundle", "-current_version", "1.2.3", "a.o",
>> + "-arch", "i386", nullptr));
>> }
>> TEST_F(DarwinLdParserTest, currentVersionInvalidValue) {
>> EXPECT_FALSE(
>> - parse("ld", "-bundle", "-current_version", "1,2,3", "a.o", nullptr));
>> + parse("ld", "-bundle", "-current_version", "1,2,3", "a.o",
>> + "-arch", "i386", nullptr));
>> }
>> TEST_F(DarwinLdParserTest, bundleLoader) {
>> EXPECT_TRUE(
>> - parse("ld", "-bundle", "-bundle_loader", "/bin/ls", "a.o", nullptr));
>> + parse("ld", "-bundle", "-bundle_loader", "/bin/ls", "a.o",
>> + "-arch", "i386", nullptr));
>> EXPECT_EQ(_context.bundleLoader(), "/bin/ls");
>> }
>> TEST_F(DarwinLdParserTest, bundleLoaderInvalidType) {
>> - EXPECT_FALSE(parse("ld", "-bundle_loader", "/bin/ls", "a.o", nullptr));
>> + EXPECT_FALSE(parse("ld", "-bundle_loader", "/bin/ls", "a.o", "-arch", "i386",
>> + nullptr));
>> }
>> TEST_F(DarwinLdParserTest, deadStrippableDylib) {
>> EXPECT_TRUE(
>> - parse("ld", "-dylib", "-mark_dead_strippable_dylib", "a.o", nullptr));
>> + parse("ld", "-dylib", "-mark_dead_strippable_dylib", "a.o",
>> + "-arch", "i386", nullptr));
>> EXPECT_EQ(true, _context.deadStrippableDylib());
>> }
>> TEST_F(DarwinLdParserTest, deadStrippableDylibInvalidType) {
>> - EXPECT_FALSE(parse("ld", "-mark_dead_strippable_dylib", "a.o", nullptr));
>> + EXPECT_FALSE(parse("ld", "-mark_dead_strippable_dylib", "a.o",
>> + "-arch", "i386", nullptr));
>> }
>> TEST_F(DarwinLdParserTest, llvmOptions) {
>> - EXPECT_TRUE(parse("ld", "-mllvm", "-debug-only", "-mllvm", "foo", "a.o", nullptr));
>> + EXPECT_TRUE(parse("ld", "-mllvm", "-debug-only", "-mllvm", "foo", "a.o",
>> + "-arch", "i386", nullptr));
>> const std::vector<const char *> &options = _context.llvmOptions();
>> EXPECT_EQ(options.size(), 2UL);
>> EXPECT_EQ(strcmp(options[0],"-debug-only"), 0);
>>
>>
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