[llvm-objcopy] Ignore -B --binary-architecture=

GNU objcopy documents that -B is only useful with architecture-less
input (i.e. "binary" or "ihex"). After D67144, -O defaults to -I, and
-B is essentially a NOP.

* If -O is binary/ihex, GNU objcopy ignores -B.
* If -O is elf*, -B provides the e_machine field in GNU objcopy.

So to convert a blob to an ELF, `-I binary -B i386:x86-64 -O elf64-x86-64` has to be specified.

`-I binary -B i386:x86-64 -O elf64-x86-64` creates an ELF with its
e_machine field set to EM_NONE in GNU objcopy, but a regular x86_64 ELF
in elftoolchain elfcopy. Follow the elftoolchain approach (ignoring -B)
to simplify code. Users that expect their command line portable should
specify -B.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D67215

llvm-svn: 371914

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/tools/llvm-objcopy/ELF/Object.cpp b/llvm/tools/llvm-objcopy/ELF/Object.cpp
index 3d1527c..79f10fe 100644
--- a/llvm/tools/llvm-objcopy/ELF/Object.cpp
+++ b/llvm/tools/llvm-objcopy/ELF/Object.cpp
@@ -1112,7 +1112,7 @@ void BasicELFBuilder::initFileHeader() {
   Obj->OSABI = ELFOSABI_NONE;
   Obj->ABIVersion = 0;
   Obj->Entry = 0x0;
-  Obj->Machine = EMachine;
+  Obj->Machine = EM_NONE;
   Obj->Version = 1;
 }
 
@@ -1606,7 +1606,7 @@ Writer::~Writer() {}
 Reader::~Reader() {}
 
 std::unique_ptr<Object> BinaryReader::create() const {
-  return BinaryELFBuilder(MInfo.EMachine, MemBuf, NewSymbolVisibility).build();
+  return BinaryELFBuilder(MemBuf, NewSymbolVisibility).build();
 }
 
 Expected<std::vector<IHexRecord>> IHexReader::parse() const {