objdump: Better handling of Mach-O universal binaries

Summary:
With Mach-O, there is a flag requirement discrepancy between working with
universal binaries and thin binaries. Many flags that don't require the `-macho`
flag (for example `-private-headers` and `-disassemble`) fail to work on
universal binaries unless `-macho` is given. When this happens, the error
message is unhelpful, stating:

    The file was not recognized as a valid object file.

Which can lead to confusion.

This change allows generic flags to be used on universal binaries with and
without the `-macho` flag. This means flags that can be used for thin files can
be used consistently with fat files too.

To do this, the universal binary support within `ParseInputMachO()` is extracted
into a new function. This new function is called directly from `DumpInput()`
when the input binary is universal. Additionally the `-arch` flag validation in
`ParseInputMachO()` was extracted to be reused.

Reviewers: compnerd

Reviewed By: compnerd

Subscribers: keith, llvm-commits

Differential Revision: https://reviews.llvm.org/D48702

llvm-svn: 338792

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 8041e6f..543de22 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -42,6 +42,7 @@
 #include "llvm/Object/COFFImportFile.h"
 #include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Object/MachO.h"
+#include "llvm/Object/MachOUniversal.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Object/Wasm.h"
 #include "llvm/Support/Casting.h"
@@ -2363,6 +2364,8 @@ static void DumpInput(StringRef file) {
     DumpArchive(a);
   else if (ObjectFile *o = dyn_cast<ObjectFile>(&Binary))
     DumpObject(o);
+  else if (MachOUniversalBinary *UB = dyn_cast<MachOUniversalBinary>(&Binary))
+    ParseInputMachO(UB);
   else
     report_error(file, object_error::invalid_file_type);
 }