Make the COFF streamer emit unwind info when processing a .seh_handlerdata

directive.

Implement emission of Win64 EH unwind info.

Pull in <cassert> in MCWin64EH.h so it can use the assert() macro.

llvm-svn: 131832

include/llvm/MC/MCStreamer.h

@@ -80,6 +80,8 @@ namespace llvm {
 
     void EmitFrames(bool usingCFI);
 
+    MCWin64EHUnwindInfo *getCurrentW64UnwindInfo(){return CurrentW64UnwindInfo;}
+
   public:
     virtual ~MCStreamer();
 

include/llvm/MC/MCWin64EH.h

@@ -16,6 +16,7 @@
 #define LLVM_MC_MCWIN64EH_H
 
 #include "llvm/Support/Win64EH.h"
+#include <cassert>
 #include <vector>
 
 namespace llvm {
@@ -59,20 +60,21 @@ namespace llvm {
 
   struct MCWin64EHUnwindInfo {
     MCWin64EHUnwindInfo() : Begin(0), End(0), ExceptionHandler(0),
-                            Function(0), PrologEnd(0), HandlesUnwind(false),
-                            HandlesExceptions(false), LastFrameInst(-1),
-                            ChainedParent(0), Instructions(), Emitted(false) {}
+                            Function(0), PrologEnd(0), Symbol(0),
+                            HandlesUnwind(false), HandlesExceptions(false),
+                            LastFrameInst(-1), ChainedParent(0),
+                            Instructions() {}
     MCSymbol *Begin;
     MCSymbol *End;
     const MCSymbol *ExceptionHandler;
     const MCSymbol *Function;
     MCSymbol *PrologEnd;
+    MCSymbol *Symbol;
     bool HandlesUnwind;
     bool HandlesExceptions;
     int LastFrameInst;
     MCWin64EHUnwindInfo *ChainedParent;
     std::vector<MCWin64EHInstruction> Instructions;
-    bool Emitted;
   };
 
   class MCWin64EHUnwindEmitter {

lib/MC/CMakeLists.txt

@@ -30,6 +30,7 @@ add_llvm_library(LLVMMC
   MCStreamer.cpp
   MCSymbol.cpp
   MCValue.cpp
+  MCWin64EH.cpp
   MachObjectWriter.cpp
   WinCOFFStreamer.cpp
   WinCOFFObjectWriter.cpp

lib/MC/MCWin64EH.cpp

@@ -0,0 +1,189 @@
+//===- 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/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;
+    case Win64EH::UOP_SaveNonVol:
+    case Win64EH::UOP_SaveXMM128:
+      count += 2;
+    case Win64EH::UOP_SaveNonVolBig:
+    case Win64EH::UOP_SaveXMM128Big:
+      count += 3;
+    case Win64EH::UOP_AllocLarge:
+      if (I->getSize() > 512*1024-8)
+        count += 3;
+      else
+        count += 2;
+    }
+  }
+  return count;
+}
+
+static void EmitUnwindCode(MCStreamer &streamer, MCWin64EHInstruction &inst) {
+  uint8_t b1, b2;
+  uint16_t w;
+  b2 = (inst.getOperation() & 0x0F) << 4;
+  switch (inst.getOperation()) {
+  case Win64EH::UOP_PushNonVol:
+    streamer.EmitIntValue(0, 1);
+    b2 |= inst.getRegister() & 0x0F;
+    streamer.EmitIntValue(b2, 1);
+    break;
+  case Win64EH::UOP_AllocLarge:
+    streamer.EmitIntValue(0, 1);
+    if (inst.getSize() > 512*1024-8) {
+      b2 |= 1;
+      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() >> 3) & 0x0F;
+    streamer.EmitIntValue(0, 1);
+    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;
+    streamer.EmitIntValue(0, 1);
+    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;
+    streamer.EmitIntValue(0, 1);
+    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 |= 1;
+    streamer.EmitIntValue(0, 1);
+    streamer.EmitIntValue(b2, 1);
+    break;
+  }
+}
+
+static void EmitRuntimeFunction(MCStreamer &streamer,
+                                MCWin64EHUnwindInfo *info) {
+  MCContext &context = streamer.getContext();
+
+  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();
+  // Upper 3 bits are the version number (currently 1).
+  uint8_t flags = 0x20;
+  info->Symbol = context.CreateTempSymbol();
+  streamer.EmitLabel(info->Symbol);
+
+  if (info->ChainedParent)
+    flags |= Win64EH::UNW_ChainInfo;
+  else {
+    if (info->HandlesUnwind)
+      flags |= Win64EH::UNW_TerminateHandler;
+    if (info->HandlesExceptions)
+      flags |= Win64EH::UNW_ExceptionHandler;
+  }
+  streamer.EmitIntValue(flags, 1);
+
+  // Build up the prolog size expression.
+  const MCExpr *prologSize = MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(
+                                                      info->PrologEnd, context),
+                                                     MCSymbolRefExpr::Create(
+                                                          info->Begin, context),
+                                                     context);
+  streamer.EmitAbsValue(prologSize, 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) << 4) |
+            ((frameInst.getOffset() >> 4) & 0x0F);
+  }
+  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, inst);
+  }
+
+  if (flags & Win64EH::UNW_ChainInfo)
+    EmitRuntimeFunction(streamer, info->ChainedParent);
+  else if (flags &(Win64EH::UNW_TerminateHandler|Win64EH::UNW_ExceptionHandler))
+    streamer.EmitValue(MCSymbolRefExpr::Create(info->ExceptionHandler, context),
+                       4);
+}
+
+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();
+  streamer.SwitchSection(xdataSect);
+
+  llvm::EmitUnwindInfo(streamer, info);
+}
+
+} // End of namespace llvm
+

lib/MC/WinCOFFStreamer.cpp

@@ -23,6 +23,7 @@
 #include "llvm/MC/MCAsmLayout.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCSectionCOFF.h"
+#include "llvm/MC/MCWin64EH.h"
 #include "llvm/Target/TargetRegistry.h"
 #include "llvm/Target/TargetAsmBackend.h"
 #include "llvm/ADT/StringMap.h"
@@ -74,6 +75,7 @@ public:
                                  unsigned MaxBytesToEmit);
   virtual void EmitFileDirective(StringRef Filename);
   virtual void EmitInstruction(const MCInst &Instruction);
+  virtual void EmitWin64EHHandlerData();
   virtual void Finish();
 
 private:
@@ -377,6 +379,14 @@ void WinCOFFStreamer::EmitInstruction(const MCInst &Instruction) {
                                                 Fragment->getFixups());
 }
 
+void WinCOFFStreamer::EmitWin64EHHandlerData() {
+  MCStreamer::EmitWin64EHHandlerData();
+
+  // We have to emit the unwind info now, because this directive
+  // actually switches to the .xdata section!
+  MCWin64EHUnwindEmitter::EmitUnwindInfo(*this, getCurrentW64UnwindInfo());
+}
+
 void WinCOFFStreamer::Finish() {
   MCObjectStreamer::Finish();
 }