Set CPU_SUBTYPE_LIB64 in mach_header.

On Mac OS 10.5 and later, with X86_64 and outputting a dynamic executable,
ld64 set the CPU_SUBTYPE_LIB64 mask on the cpusubtype in the mach_header.

This adds the same functionality to lld.

rdar://problem/24507177

llvm-svn: 259826

2 files changed, 48 insertions, 1 deletions

diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
index 4e303dd8b97..6814a16189c 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
@@ -607,10 +607,23 @@ size_t MachOFileLayout::size() const {
 }
 
 void MachOFileLayout::writeMachHeader() {
+  auto cpusubtype = MachOLinkingContext::cpuSubtypeFromArch(_file.arch);
+  // dynamic x86 executables on newer OS version should also set the
+  // CPU_SUBTYPE_LIB64 mask in the CPU subtype.
+  // FIXME: Check that this is a dynamic executable, not a static one.
+  if (_file.fileType == llvm::MachO::MH_EXECUTE &&
+      cpusubtype == CPU_SUBTYPE_X86_64_ALL &&
+      _file.os == MachOLinkingContext::OS::macOSX) {
+    uint32_t version;
+    bool failed = MachOLinkingContext::parsePackedVersion("10.5", version);
+    if (!failed && _file.minOSverson >= version)
+      cpusubtype |= CPU_SUBTYPE_LIB64;
+  }
+
   mach_header *mh = reinterpret_cast<mach_header*>(_buffer);
   mh->magic = _is64 ? llvm::MachO::MH_MAGIC_64 : llvm::MachO::MH_MAGIC;
   mh->cputype =  MachOLinkingContext::cpuTypeFromArch(_file.arch);
-  mh->cpusubtype = MachOLinkingContext::cpuSubtypeFromArch(_file.arch);
+  mh->cpusubtype = cpusubtype;
   mh->filetype = _file.fileType;
   mh->ncmds = _countOfLoadCommands;
   mh->sizeofcmds = _endOfLoadCommands - _startOfLoadCommands;
diff --git a/lld/test/mach-o/mach_header-cpusubtype.yaml b/lld/test/mach-o/mach_header-cpusubtype.yaml
new file mode 100644
index 00000000000..fa9024f999d
--- /dev/null
+++ b/lld/test/mach-o/mach_header-cpusubtype.yaml
@@ -0,0 +1,34 @@
+# RUN: lld -flavor darwin -arch x86_64 -macosx_version_min 10.4 %s %p/Inputs/hello-world-x86_64.yaml -o %t && llvm-objdump -private-headers %t | FileCheck %s --check-prefix=NO_LIB64
+# RUN: lld -flavor darwin -arch x86_64 -macosx_version_min 10.5 %s %p/Inputs/hello-world-x86_64.yaml -o %t && llvm-objdump -private-headers %t | FileCheck %s --check-prefix=LIB64
+# RUN: lld -flavor darwin -arch x86_64 -dylib -macosx_version_min 10.5 %s %p/Inputs/hello-world-x86_64.yaml -o %t && llvm-objdump -private-headers %t | FileCheck %s --check-prefix=DYLIB
+
+--- !mach-o
+arch:            x86_64
+file-type:       MH_OBJECT
+flags:           [ MH_SUBSECTIONS_VIA_SYMBOLS ]
+has-UUID:        false
+OS:              unknown
+sections:
+  - segment:         __TEXT
+    section:         __text
+    type:            S_REGULAR
+    attributes:      [ S_ATTR_PURE_INSTRUCTIONS, S_ATTR_SOME_INSTRUCTIONS ]
+    address:         0x0000000000000000
+    content:         [ 0x00, 0x00 ]
+global-symbols:
+  - name:            _main
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000000
+  - name:            start
+    type:            N_SECT
+    scope:           [ N_EXT ]
+    sect:            1
+    value:           0x0000000000000001
+
+...
+
+# NO_LIB64: MH_MAGIC_64  X86_64        ALL 0x00     EXECUTE
+# LIB64: MH_MAGIC_64  X86_64        ALL LIB64     EXECUTE
+# DYLIB: MH_MAGIC_64 X86_64 ALL 0x00 DYLIB