//===-------------- MachO.cpp - JIT linker function for MachO -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// MachO jit-link function.
//
//===----------------------------------------------------------------------===//

#include "llvm/ExecutionEngine/JITLink/MachO.h"

#include "llvm/BinaryFormat/MachO.h"
#include "llvm/ExecutionEngine/JITLink/MachO_arm64.h"
#include "llvm/ExecutionEngine/JITLink/MachO_x86_64.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SwapByteOrder.h"

using namespace llvm;

#define DEBUG_TYPE "jitlink"

namespace llvm {
namespace jitlink {

Expected<std::unique_ptr<LinkGraph>>
createLinkGraphFromMachOObject(MemoryBufferRef ObjectBuffer) {
  StringRef Data = ObjectBuffer.getBuffer();
  if (Data.size() < 4)
    return make_error<JITLinkError>("Truncated MachO buffer \"" +
                                    ObjectBuffer.getBufferIdentifier() + "\"");

  uint32_t Magic;
  memcpy(&Magic, Data.data(), sizeof(uint32_t));
  LLVM_DEBUG({
    dbgs() << "jitLink_MachO: magic = " << format("0x%08" PRIx32, Magic)
           << ", identifier = \"" << ObjectBuffer.getBufferIdentifier()
           << "\"\n";
  });

  if (Magic == MachO::MH_MAGIC || Magic == MachO::MH_CIGAM)
    return make_error<JITLinkError>("MachO 32-bit platforms not supported");
  else if (Magic == MachO::MH_MAGIC_64 || Magic == MachO::MH_CIGAM_64) {

    if (Data.size() < sizeof(MachO::mach_header_64))
      return make_error<JITLinkError>("Truncated MachO buffer \"" +
                                      ObjectBuffer.getBufferIdentifier() +
                                      "\"");

    // Read the CPU type from the header.
    uint32_t CPUType;
    memcpy(&CPUType, Data.data() + 4, sizeof(uint32_t));
    if (Magic == MachO::MH_CIGAM_64)
      CPUType = llvm::byteswap<uint32_t>(CPUType);

    LLVM_DEBUG({
      dbgs() << "jitLink_MachO: cputype = " << format("0x%08" PRIx32, CPUType)
             << "\n";
    });

    switch (CPUType) {
    case MachO::CPU_TYPE_ARM64:
      return createLinkGraphFromMachOObject_arm64(ObjectBuffer);
    case MachO::CPU_TYPE_X86_64:
      return createLinkGraphFromMachOObject_x86_64(ObjectBuffer);
    }
    return make_error<JITLinkError>("MachO-64 CPU type not valid");
  } else
    return make_error<JITLinkError>("Unrecognized MachO magic value");
}

void link_MachO(std::unique_ptr<LinkGraph> G,
                std::unique_ptr<JITLinkContext> Ctx) {

  switch (G->getTargetTriple().getArch()) {
  case Triple::aarch64:
    return link_MachO_arm64(std::move(G), std::move(Ctx));
  case Triple::x86_64:
    return link_MachO_x86_64(std::move(G), std::move(Ctx));
  default:
    Ctx->notifyFailed(make_error<JITLinkError>("MachO-64 CPU type not valid"));
    return;
  }
}

} // end namespace jitlink
} // end namespace llvm