Basic support for parsing Mach-O universal binaries in LLVMObject library

llvm-svn: 184191

1 files changed, 139 insertions, 0 deletions

diff --git a/llvm/lib/Object/MachOUniversal.cpp b/llvm/lib/Object/MachOUniversal.cpp
new file mode 100644
index 00000000000..98f7198bdb1
--- /dev/null
+++ b/llvm/lib/Object/MachOUniversal.cpp
@@ -0,0 +1,139 @@
+//===- MachOUniversal.cpp - Mach-O universal binary -------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the MachOUniversalBinary class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/MachOUniversal.h"
+
+#include "llvm/Object/MachO.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/MemoryBuffer.h"
+
+using namespace llvm;
+using namespace object;
+
+template<typename T>
+static void SwapValue(T &Value) {
+  Value = sys::SwapByteOrder(Value);
+}
+
+template<typename T>
+static void SwapStruct(T &Value);
+
+template<>
+void SwapStruct(macho::FatHeader &H) {
+  SwapValue(H.Magic);
+  SwapValue(H.NumFatArch);
+}
+
+template<>
+void SwapStruct(macho::FatArchHeader &H) {
+  SwapValue(H.CPUType);
+  SwapValue(H.CPUSubtype);
+  SwapValue(H.Offset);
+  SwapValue(H.Size);
+  SwapValue(H.Align);
+}
+
+template<typename T>
+static T getUniversalBinaryStruct(const char *Ptr) {
+  T Res;
+  memcpy(&Res, Ptr, sizeof(T));
+  // Universal binary headers have big-endian byte order.
+  if (sys::IsLittleEndianHost)
+    SwapStruct(Res);
+  return Res;
+}
+
+MachOUniversalBinary::ObjectForArch::ObjectForArch(
+    const MachOUniversalBinary *Parent, uint32_t Index)
+    : Parent(Parent), Index(Index) {
+  if (Parent == 0 || Index > Parent->getNumberOfObjects()) {
+    clear();
+  } else {
+    // Parse object header.
+    StringRef ParentData = Parent->getData();
+    const char *HeaderPos = ParentData.begin() + macho::FatHeaderSize +
+                            Index * macho::FatArchHeaderSize;
+    Header = getUniversalBinaryStruct<macho::FatArchHeader>(HeaderPos);
+    if (ParentData.size() < Header.Offset + Header.Size) {
+      clear();
+    }
+  }
+}
+
+error_code MachOUniversalBinary::ObjectForArch::getAsObjectFile(
+    OwningPtr<ObjectFile> &Result) const {
+  if (Parent) {
+    StringRef ParentData = Parent->getData();
+    StringRef ObjectData = ParentData.substr(Header.Offset, Header.Size);
+    Twine ObjectName =
+        Twine(Parent->getFileName()) + ":" +
+        Triple::getArchTypeName(MachOObjectFile::getArch(Header.CPUType));
+    MemoryBuffer *ObjBuffer = MemoryBuffer::getMemBuffer(
+        ObjectData, ObjectName.str(), false);
+    if (ObjectFile *Obj = ObjectFile::createMachOObjectFile(ObjBuffer)) {
+      Result.reset(Obj);
+      return object_error::success;
+    }
+  }
+  return object_error::parse_failed;
+}
+
+void MachOUniversalBinary::anchor() { }
+
+MachOUniversalBinary::MachOUniversalBinary(MemoryBuffer *Source,
+                                           error_code &ec)
+  : Binary(Binary::ID_MachOUniversalBinary, Source),
+    NumberOfObjects(0) {
+  if (Source->getBufferSize() < macho::FatHeaderSize) {
+    ec = object_error::invalid_file_type;
+    return;
+  }
+  // Check for magic value and sufficient header size.
+  StringRef Buf = getData();
+  macho::FatHeader H = getUniversalBinaryStruct<macho::FatHeader>(Buf.begin());
+  NumberOfObjects = H.NumFatArch;
+  uint32_t MinSize = macho::FatHeaderSize +
+                     macho::FatArchHeaderSize * NumberOfObjects;
+  if (H.Magic != macho::HM_Universal || Buf.size() < MinSize) {
+    ec = object_error::parse_failed;
+    return;
+  }
+  ec = object_error::success;
+}
+
+static bool getCTMForArch(Triple::ArchType Arch, mach::CPUTypeMachine &CTM) {
+  switch (Arch) {
+    case Triple::x86:    CTM = mach::CTM_i386; return true;
+    case Triple::x86_64: CTM = mach::CTM_x86_64; return true;
+    case Triple::arm:    CTM = mach::CTM_ARM; return true;
+    case Triple::sparc:  CTM = mach::CTM_SPARC; return true;
+    case Triple::ppc:    CTM = mach::CTM_PowerPC; return true;
+    case Triple::ppc64:  CTM = mach::CTM_PowerPC64; return true;
+    default: return false;
+  }
+}
+
+error_code
+MachOUniversalBinary::getObjectForArch(Triple::ArchType Arch,
+                                       OwningPtr<ObjectFile> &Result) const {
+  mach::CPUTypeMachine CTM;
+  if (!getCTMForArch(Arch, CTM))
+    return object_error::arch_not_found;
+  for (object_iterator I = begin_objects(), E = end_objects(); I != E; ++I) {
+    if (I->getCPUType() == static_cast<uint32_t>(CTM))
+      return I->getAsObjectFile(Result);
+  }
+  return object_error::arch_not_found;
+}