[LLVM-C] Add Accessor for Mach-O Universal Binary Slices

Summary: Allow for retrieving an object file corresponding to an architecture-specific slice in a Mach-O universal binary file.

Reviewers: whitequark, deadalnix

Reviewed By: whitequark

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60378

llvm-svn: 361705

Author: CodaFi

llvm/include/llvm-c/Object.h

@@ -102,6 +102,22 @@ LLVMMemoryBufferRef LLVMBinaryCopyMemoryBuffer(LLVMBinaryRef BR);
  */
 LLVMBinaryType LLVMBinaryGetType(LLVMBinaryRef BR);
 
+/*
+ * For a Mach-O universal binary file, retrieves the object file corresponding
+ * to the given architecture if it is present as a slice.
+ *
+ * If NULL is returned, the \p ErrorMessage parameter is populated with the
+ * error's description.  It is then the caller's responsibility to free this
+ * message by calling \c LLVMDisposeMessage.
+ *
+ * It is the responsiblity of the caller to free the returned object file by
+ * calling \c LLVMDisposeBinary.
+ */
+LLVMBinaryRef LLVMMachOUniversalBinaryCopyObjectForArch(LLVMBinaryRef BR,
+                                                        const char *Arch,
+                                                        size_t ArchLen,
+                                                        char **ErrorMessage);
+
 /**
  * Retrieve a copy of the section iterator for this object file.
  *

llvm/lib/Object/Object.cpp

@@ -15,6 +15,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/Object/ObjectFile.h"
+#include "llvm/Object/MachOUniversal.h"
 
 using namespace llvm;
 using namespace object;
@@ -131,6 +132,20 @@ LLVMBinaryType LLVMBinaryGetType(LLVMBinaryRef BR) {
   return BinaryTypeMapper::mapBinaryTypeToLLVMBinaryType(unwrap(BR)->getType());
 }
 
+LLVMBinaryRef LLVMMachOUniversalBinaryCopyObjectForArch(LLVMBinaryRef BR,
+                                                        const char *Arch,
+                                                        size_t ArchLen,
+                                                        char **ErrorMessage) {
+  auto universal = cast<MachOUniversalBinary>(unwrap(BR));
+  Expected<std::unique_ptr<ObjectFile>> ObjOrErr(
+      universal->getObjectForArch({Arch, ArchLen}));
+  if (!ObjOrErr) {
+    *ErrorMessage = strdup(toString(ObjOrErr.takeError()).c_str());
+    return nullptr;
+  }
+  return wrap(ObjOrErr.get().release());
+}
+
 LLVMSectionIteratorRef LLVMObjectFileCopySectionIterator(LLVMBinaryRef BR) {
   auto OF = cast<ObjectFile>(unwrap(BR));
   auto sections = OF->sections();