1 files changed, 151 insertions, 0 deletions
diff --git a/lib/ReaderWriter/ELF/X86_64/X86_64RelocationHandler.cpp b/lib/ReaderWriter/ELF/X86_64/X86_64RelocationHandler.cpp
new file mode 100644
index 0000000000000..8fd74f43bbd28
--- /dev/null
+++ b/lib/ReaderWriter/ELF/X86_64/X86_64RelocationHandler.cpp
@@ -0,0 +1,151 @@
+//===- lib/ReaderWriter/ELF/X86_64/X86_64RelocationHandler.cpp ------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "X86_64LinkingContext.h"
+#include "X86_64TargetHandler.h"
+#include "llvm/Support/Endian.h"
+
+using namespace lld;
+using namespace lld::elf;
+using namespace llvm::support::endian;
+
+/// \brief R_X86_64_64 - word64: S + A
+static void reloc64(uint8_t *location, uint64_t P, uint64_t S, int64_t A) {
+  uint64_t result = S + A;
+  write64le(location, result | read64le(location));
+}
+
+/// \brief R_X86_64_PC32 - word32: S + A - P
+static void relocPC32(uint8_t *location, uint64_t P, uint64_t S, int64_t A) {
+  uint32_t result = (uint32_t)((S + A) - P);
+  write32le(location, result + read32le(location));
+}
+
+/// \brief R_X86_64_32 - word32:  S + A
+static void reloc32(uint8_t *location, uint64_t P, uint64_t S, int64_t A) {
+  int32_t result = (uint32_t)(S + A);
+  write32le(location, result | read32le(location));
+  // TODO: Make sure that the result zero extends to the 64bit value.
+}
+
+/// \brief R_X86_64_32S - word32:  S + A
+static void reloc32S(uint8_t *location, uint64_t P, uint64_t S, int64_t A) {
+  int32_t result = (int32_t)(S + A);
+  write32le(location, result | read32le(location));
+  // TODO: Make sure that the result sign extends to the 64bit value.
+}
+
+/// \brief R_X86_64_16 - word16:  S + A
+static void reloc16(uint8_t *location, uint64_t P, uint64_t S, int64_t A) {
+  uint16_t result = (uint16_t)(S + A);
+  write16le(location, result | read16le(location));
+  // TODO: Check for overflow.
+}
+
+/// \brief R_X86_64_PC16 - word16: S + A - P
+static void relocPC16(uint8_t *location, uint64_t P, uint64_t S, int64_t A) {
+  uint16_t result = (uint16_t)((S + A) - P);
+  write16le(location, result | read16le(location));
+  // TODO: Check for overflow.
+}
+
+/// \brief R_X86_64_PC64 - word64: S + A - P
+static void relocPC64(uint8_t *location, uint64_t P, uint64_t S, uint64_t A) {
+  int64_t result = (uint64_t)((S + A) - P);
+  write64le(location, result | read64le(location));
+}
+
+std::error_code X86_64TargetRelocationHandler::applyRelocation(
+    ELFWriter &writer, llvm::FileOutputBuffer &buf, const lld::AtomLayout &atom,
+    const Reference &ref) const {
+  uint8_t *atomContent = buf.getBufferStart() + atom._fileOffset;
+  uint8_t *location = atomContent + ref.offsetInAtom();
+  uint64_t targetVAddress = writer.addressOfAtom(ref.target());
+  uint64_t relocVAddress = atom._virtualAddr + ref.offsetInAtom();
+
+  if (ref.kindNamespace() != Reference::KindNamespace::ELF)
+    return std::error_code();
+  assert(ref.kindArch() == Reference::KindArch::x86_64);
+  switch (ref.kindValue()) {
+  case R_X86_64_NONE:
+    break;
+  case R_X86_64_64:
+    reloc64(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  case R_X86_64_PC32:
+  case R_X86_64_GOTPCREL:
+    relocPC32(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  case R_X86_64_32:
+    reloc32(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  case R_X86_64_32S:
+    reloc32S(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  case R_X86_64_16:
+    reloc16(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  case R_X86_64_PC16:
+    relocPC16(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  case R_X86_64_TPOFF64:
+  case R_X86_64_DTPOFF32:
+  case R_X86_64_TPOFF32: {
+    _tlsSize = _x86_64Layout.getTLSSize();
+    if (ref.kindValue() == R_X86_64_TPOFF32 ||
+        ref.kindValue() == R_X86_64_DTPOFF32) {
+      write32le(location, targetVAddress - _tlsSize);
+    } else {
+      write64le(location, targetVAddress - _tlsSize);
+    }
+    break;
+  }
+  case R_X86_64_TLSGD: {
+    relocPC32(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  }
+  case R_X86_64_TLSLD: {
+    // Rewrite to move %fs:0 into %rax. Technically we should verify that the
+    // next relocation is a PC32 to __tls_get_addr...
+    static uint8_t instr[] = { 0x66, 0x66, 0x66, 0x64, 0x48, 0x8b, 0x04, 0x25,
+                               0x00, 0x00, 0x00, 0x00 };
+    std::memcpy(location - 3, instr, sizeof(instr));
+    break;
+  }
+  case R_X86_64_PC64:
+    relocPC64(location, relocVAddress, targetVAddress, ref.addend());
+    break;
+  case LLD_R_X86_64_GOTRELINDEX: {
+    const DefinedAtom *target = cast<const DefinedAtom>(ref.target());
+    for (const Reference *r : *target) {
+      if (r->kindValue() == R_X86_64_JUMP_SLOT) {
+        uint32_t index;
+        if (!_x86_64Layout.getPLTRelocationTable()->getRelocationIndex(*r,
+                                                                       index))
+          llvm_unreachable("Relocation doesn't exist");
+        reloc32(location, 0, index, 0);
+        break;
+      }
+    }
+    break;
+  }
+  // Runtime only relocations. Ignore here.
+  case R_X86_64_RELATIVE:
+  case R_X86_64_IRELATIVE:
+  case R_X86_64_JUMP_SLOT:
+  case R_X86_64_GLOB_DAT:
+  case R_X86_64_DTPMOD64:
+  case R_X86_64_DTPOFF64:
+    break;
+  default:
+    return make_unhandled_reloc_error();
+  }
+
+  return std::error_code();
+}