[macho] Minor install_name fixes

Summary:
Fix the binary file reader to properly read dyld version info.
Update the install_name test case to properly test the binary reader. We can't use '-print_atoms' as the output format is 'native' yaml and it does not contains the dyld current and compatibility versions. 

Also change the timestamp value of LD_ID_DYLD to match the one generated by ld64.
The dynamic linker (dyld) used to expects different values for timestamp in LD_ID_DYLD and LD_LOAD_DYLD for prebound images. While prebinding is deprecated, we should probably keep it safe and match ld64. 

Reviewers: kledzik

Subscribers: llvm-commits

Projects: #lld

Differential Revision: http://reviews.llvm.org/D6736

llvm-svn: 224681

1 files changed, 3 insertions, 1 deletions

diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
index a3542c4fc50..be7acf9d4d6 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
@@ -741,7 +741,8 @@ std::error_code MachOFileLayout::writeLoadCommands() {
       dc->cmd                         = LC_ID_DYLIB;
       dc->cmdsize                     = size;
       dc->dylib.name                  = sizeof(dylib_command); // offset
-      dc->dylib.timestamp             = 2;
+      // needs to be some constant value different than the one in LC_LOAD_DYLIB
+      dc->dylib.timestamp             = 1;
       dc->dylib.current_version       = _file.currentVersion;
       dc->dylib.compatibility_version = _file.compatVersion;
       if (_swap)
@@ -841,6 +842,7 @@ std::error_code MachOFileLayout::writeLoadCommands() {
       dc->cmd                         = dep.kind;
       dc->cmdsize                     = size;
       dc->dylib.name                  = sizeof(dylib_command); // offset
+      // needs to be some constant value different than the one in LC_ID_DYLIB
       dc->dylib.timestamp             = 2;
       dc->dylib.current_version       = dep.currentVersion;
       dc->dylib.compatibility_version = dep.compatVersion;