1 files changed, 258 insertions, 0 deletions
diff --git a/lib/MC/MCWin64EH.cpp b/lib/MC/MCWin64EH.cpp
new file mode 100644
index 0000000..9453f5c
--- /dev/null
+++ b/lib/MC/MCWin64EH.cpp
@@ -0,0 +1,258 @@
+//===- lib/MC/MCWin64EH.cpp - MCWin64EH implementation --------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCWin64EH.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCSectionCOFF.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/Target/TargetAsmInfo.h"
+
+namespace llvm {
+
+// NOTE: All relocations generated here are 4-byte image-relative.
+
+static uint8_t CountOfUnwindCodes(std::vector<MCWin64EHInstruction> &instArray){
+  uint8_t count = 0;
+  for (std::vector<MCWin64EHInstruction>::const_iterator I = instArray.begin(),
+       E = instArray.end(); I != E; ++I) {
+    switch (I->getOperation()) {
+    case Win64EH::UOP_PushNonVol:
+    case Win64EH::UOP_AllocSmall:
+    case Win64EH::UOP_SetFPReg:
+    case Win64EH::UOP_PushMachFrame:
+      count += 1;
+      break;
+    case Win64EH::UOP_SaveNonVol:
+    case Win64EH::UOP_SaveXMM128:
+      count += 2;
+      break;
+    case Win64EH::UOP_SaveNonVolBig:
+    case Win64EH::UOP_SaveXMM128Big:
+      count += 3;
+      break;
+    case Win64EH::UOP_AllocLarge:
+      if (I->getSize() > 512*1024-8)
+        count += 3;
+      else
+        count += 2;
+      break;
+    }
+  }
+  return count;
+}
+
+static void EmitAbsDifference(MCStreamer &streamer, MCSymbol *lhs,
+                              MCSymbol *rhs) {
+  MCContext &context = streamer.getContext();
+  const MCExpr *diff = MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(
+                                                                  lhs, context),
+                                               MCSymbolRefExpr::Create(
+                                                                  rhs, context),
+                                               context);
+  streamer.EmitAbsValue(diff, 1);
+
+}
+
+static void EmitUnwindCode(MCStreamer &streamer, MCSymbol *begin,
+                           MCWin64EHInstruction &inst) {
+  uint8_t b1, b2;
+  uint16_t w;
+  b2 = (inst.getOperation() & 0x0F);
+  switch (inst.getOperation()) {
+  case Win64EH::UOP_PushNonVol:
+    EmitAbsDifference(streamer, inst.getLabel(), begin);
+    b2 |= (inst.getRegister() & 0x0F) << 4;
+    streamer.EmitIntValue(b2, 1);
+    break;
+  case Win64EH::UOP_AllocLarge:
+    EmitAbsDifference(streamer, inst.getLabel(), begin);
+    if (inst.getSize() > 512*1024-8) {
+      b2 |= 0x10;
+      streamer.EmitIntValue(b2, 1);
+      w = inst.getSize() & 0xFFF8;
+      streamer.EmitIntValue(w, 2);
+      w = inst.getSize() >> 16;
+    } else {
+      streamer.EmitIntValue(b2, 1);
+      w = inst.getSize() >> 3;
+    }
+    streamer.EmitIntValue(w, 2);
+    break;
+  case Win64EH::UOP_AllocSmall:
+    b2 |= (((inst.getSize()-8) >> 3) & 0x0F) << 4;
+    EmitAbsDifference(streamer, inst.getLabel(), begin);
+    streamer.EmitIntValue(b2, 1);
+    break;
+  case Win64EH::UOP_SetFPReg:
+    b1 = inst.getOffset() & 0xF0;
+    streamer.EmitIntValue(b1, 1);
+    streamer.EmitIntValue(b2, 1);
+    break;
+  case Win64EH::UOP_SaveNonVol:
+  case Win64EH::UOP_SaveXMM128:
+    b2 |= (inst.getRegister() & 0x0F) << 4;
+    EmitAbsDifference(streamer, inst.getLabel(), begin);
+    streamer.EmitIntValue(b2, 1);
+    w = inst.getOffset() >> 3;
+    if (inst.getOperation() == Win64EH::UOP_SaveXMM128)
+      w >>= 1;
+    streamer.EmitIntValue(w, 2);
+    break;
+  case Win64EH::UOP_SaveNonVolBig:
+  case Win64EH::UOP_SaveXMM128Big:
+    b2 |= (inst.getRegister() & 0x0F) << 4;
+    EmitAbsDifference(streamer, inst.getLabel(), begin);
+    streamer.EmitIntValue(b2, 1);
+    if (inst.getOperation() == Win64EH::UOP_SaveXMM128Big)
+      w = inst.getOffset() & 0xFFF0;
+    else
+      w = inst.getOffset() & 0xFFF8;
+    streamer.EmitIntValue(w, 2);
+    w = inst.getOffset() >> 16;
+    streamer.EmitIntValue(w, 2);
+    break;
+  case Win64EH::UOP_PushMachFrame:
+    if (inst.isPushCodeFrame())
+      b2 |= 0x10;
+    EmitAbsDifference(streamer, inst.getLabel(), begin);
+    streamer.EmitIntValue(b2, 1);
+    break;
+  }
+}
+
+static void EmitRuntimeFunction(MCStreamer &streamer,
+                                const MCWin64EHUnwindInfo *info) {
+  MCContext &context = streamer.getContext();
+
+  streamer.EmitValueToAlignment(4);
+  streamer.EmitValue(MCSymbolRefExpr::Create(info->Begin, context), 4);
+  streamer.EmitValue(MCSymbolRefExpr::Create(info->End, context), 4);
+  streamer.EmitValue(MCSymbolRefExpr::Create(info->Symbol, context), 4);
+}
+
+static void EmitUnwindInfo(MCStreamer &streamer, MCWin64EHUnwindInfo *info) {
+  // If this UNWIND_INFO already has a symbol, it's already been emitted.
+  if (info->Symbol) return;
+
+  MCContext &context = streamer.getContext();
+  streamer.EmitValueToAlignment(4);
+  // Upper 3 bits are the version number (currently 1).
+  uint8_t flags = 0x01;
+  info->Symbol = context.CreateTempSymbol();
+  streamer.EmitLabel(info->Symbol);
+
+  if (info->ChainedParent)
+    flags |= Win64EH::UNW_ChainInfo << 3;
+  else {
+    if (info->HandlesUnwind)
+      flags |= Win64EH::UNW_TerminateHandler << 3;
+    if (info->HandlesExceptions)
+      flags |= Win64EH::UNW_ExceptionHandler << 3;
+  }
+  streamer.EmitIntValue(flags, 1);
+
+  if (info->PrologEnd)
+    EmitAbsDifference(streamer, info->PrologEnd, info->Begin);
+  else
+    streamer.EmitIntValue(0, 1);
+
+  uint8_t numCodes = CountOfUnwindCodes(info->Instructions);
+  streamer.EmitIntValue(numCodes, 1);
+
+  uint8_t frame = 0;
+  if (info->LastFrameInst >= 0) {
+    MCWin64EHInstruction &frameInst = info->Instructions[info->LastFrameInst];
+    assert(frameInst.getOperation() == Win64EH::UOP_SetFPReg);
+    frame = (frameInst.getRegister() & 0x0F) |
+            (frameInst.getOffset() & 0xF0);
+  }
+  streamer.EmitIntValue(frame, 1);
+
+  // Emit unwind instructions (in reverse order).
+  uint8_t numInst = info->Instructions.size();
+  for (uint8_t c = 0; c < numInst; ++c) {
+    MCWin64EHInstruction inst = info->Instructions.back();
+    info->Instructions.pop_back();
+    EmitUnwindCode(streamer, info->Begin, inst);
+  }
+
+  if (flags & (Win64EH::UNW_ChainInfo << 3))
+    EmitRuntimeFunction(streamer, info->ChainedParent);
+  else if (flags &
+           ((Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler) << 3))
+    streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
+                       4);
+  else if (numCodes < 2) {
+    // The minimum size of an UNWIND_INFO struct is 8 bytes. If we're not
+    // a chained unwind info, if there is no handler, and if there are fewer
+    // than 2 slots used in the unwind code array, we have to pad to 8 bytes.
+    if (numCodes == 1)
+      streamer.EmitIntValue(0, 2);
+    else
+      streamer.EmitIntValue(0, 4);
+  }
+}
+
+StringRef MCWin64EHUnwindEmitter::GetSectionSuffix(const MCSymbol *func) {
+  if (!func || !func->isInSection()) return "";
+  const MCSection *section = &func->getSection();
+  const MCSectionCOFF *COFFSection;
+  if ((COFFSection = dyn_cast<MCSectionCOFF>(section))) {
+    StringRef name = COFFSection->getSectionName();
+    size_t dollar = name.find('$');
+    size_t dot = name.find('.', 1);
+    if (dollar == StringRef::npos && dot == StringRef::npos)
+      return "";
+    if (dot == StringRef::npos)
+      return name.substr(dollar);
+    if (dollar == StringRef::npos || dot < dollar)
+      return name.substr(dot);
+    return name.substr(dollar);
+  }
+  return "";
+}
+
+void MCWin64EHUnwindEmitter::EmitUnwindInfo(MCStreamer &streamer,
+                                            MCWin64EHUnwindInfo *info) {
+  // Switch sections (the static function above is meant to be called from
+  // here and from Emit().
+  MCContext &context = streamer.getContext();
+  const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
+  const MCSection *xdataSect =
+    asmInfo.getWin64EHTableSection(GetSectionSuffix(info->Function));
+  streamer.SwitchSection(xdataSect);
+
+  llvm::EmitUnwindInfo(streamer, info);
+}
+
+void MCWin64EHUnwindEmitter::Emit(MCStreamer &streamer) {
+  MCContext &context = streamer.getContext();
+  // Emit the unwind info structs first.
+  const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
+  for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i) {
+    MCWin64EHUnwindInfo &info = streamer.getW64UnwindInfo(i);
+    const MCSection *xdataSect =
+      asmInfo.getWin64EHTableSection(GetSectionSuffix(info.Function));
+    streamer.SwitchSection(xdataSect);
+    llvm::EmitUnwindInfo(streamer, &info);
+  }
+  // Now emit RUNTIME_FUNCTION entries.
+  for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i) {
+    MCWin64EHUnwindInfo &info = streamer.getW64UnwindInfo(i);
+    const MCSection *pdataSect =
+      asmInfo.getWin64EHFuncTableSection(GetSectionSuffix(info.Function));
+    streamer.SwitchSection(pdataSect);
+    EmitRuntimeFunction(streamer, &info);
+  }
+}
+
+} // End of namespace llvm
+