[WinEH] Run cleanup handlers when an exception is thrown

Generate tables in the .xdata section representing what actions to take
when an exception is thrown.  This currently fills in state for
cleanups, catch handlers are still unfinished.

llvm-svn: 233636

1 files changed, 210 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
index 7d76eaddb56..974e94dcb6a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/Win64Exception.cpp
@@ -19,6 +19,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/WinEHFuncInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Mangler.h"
 #include "llvm/IR/Module.h"
@@ -82,7 +83,7 @@ void Win64Exception::beginFunction(const MachineFunction *MF) {
 
 /// endFunction - Gather and emit post-function exception information.
 ///
-void Win64Exception::endFunction(const MachineFunction *) {
+void Win64Exception::endFunction(const MachineFunction *MF) {
   if (!shouldEmitPersonality && !shouldEmitMoves)
     return;
 
@@ -100,6 +101,8 @@ void Win64Exception::endFunction(const MachineFunction *) {
     EHPersonality Per = MMI->getPersonalityType();
     if (Per == EHPersonality::MSVC_Win64SEH)
       emitCSpecificHandlerTable();
+    else if (Per == EHPersonality::MSVC_CXX)
+      emitCXXFrameHandler3Table(MF);
     else
       emitExceptionTable();
 
@@ -108,11 +111,19 @@ void Win64Exception::endFunction(const MachineFunction *) {
   Asm->OutStreamer.EmitWinCFIEndProc();
 }
 
-const MCSymbolRefExpr *Win64Exception::createImageRel32(const MCSymbol *Value) {
+const MCExpr *Win64Exception::createImageRel32(const MCSymbol *Value) {
+  if (!Value)
+    return MCConstantExpr::Create(0, Asm->OutContext);
   return MCSymbolRefExpr::Create(Value, MCSymbolRefExpr::VK_COFF_IMGREL32,
                                  Asm->OutContext);
 }
 
+const MCExpr *Win64Exception::createImageRel32(const GlobalValue *GV) {
+  if (!GV)
+    return MCConstantExpr::Create(0, Asm->OutContext);
+  return createImageRel32(Asm->getSymbol(GV));
+}
+
 /// Emit the language-specific data that __C_specific_handler expects.  This
 /// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
 /// up after faults with __try, __except, and __finally.  The typeinfo values
@@ -237,3 +248,200 @@ void Win64Exception::emitCSpecificHandlerTable() {
     }
   }
 }
+
+void Win64Exception::emitCXXFrameHandler3Table(const MachineFunction *MF) {
+  const Function *F = MF->getFunction();
+  const Function *ParentF = MMI->getWinEHParent(F);
+  auto &OS = Asm->OutStreamer;
+
+  StringRef ParentLinkageName =
+      GlobalValue::getRealLinkageName(ParentF->getName());
+
+  MCSymbol *FuncInfoXData =
+      Asm->OutContext.GetOrCreateSymbol(Twine("$cppxdata$", ParentLinkageName));
+  OS.EmitValue(createImageRel32(FuncInfoXData), 4);
+
+  // The Itanium LSDA table sorts similar landing pads together to simplify the
+  // actions table, but we don't need that.
+  SmallVector<const LandingPadInfo *, 64> LandingPads;
+  const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
+  LandingPads.reserve(PadInfos.size());
+  for (const auto &LP : PadInfos)
+    LandingPads.push_back(&LP);
+
+  RangeMapType PadMap;
+  computePadMap(LandingPads, PadMap);
+
+  // The end label of the previous invoke or nounwind try-range.
+  MCSymbol *LastLabel = Asm->getFunctionBegin();
+
+  // Whether there is a potentially throwing instruction (currently this means
+  // an ordinary call) between the end of the previous try-range and now.
+  bool SawPotentiallyThrowing = false;
+
+  WinEHFuncInfo &FuncInfo = MMI->getWinEHFuncInfo(ParentF);
+
+  int LastEHState = -2;
+
+  // The parent function and the catch handlers contribute to the 'ip2state'
+  // table.
+  for (const auto &MBB : *MF) {
+    for (const auto &MI : MBB) {
+      if (!MI.isEHLabel()) {
+        if (MI.isCall())
+          SawPotentiallyThrowing |= !callToNoUnwindFunction(&MI);
+        continue;
+      }
+
+      // End of the previous try-range?
+      MCSymbol *BeginLabel = MI.getOperand(0).getMCSymbol();
+      if (BeginLabel == LastLabel)
+        SawPotentiallyThrowing = false;
+
+      // Beginning of a new try-range?
+      RangeMapType::const_iterator L = PadMap.find(BeginLabel);
+      if (L == PadMap.end())
+        // Nope, it was just some random label.
+        continue;
+
+      const PadRange &P = L->second;
+      const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
+      assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
+             "Inconsistent landing pad map!");
+
+      if (SawPotentiallyThrowing) {
+        FuncInfo.IPToStateList.push_back(std::make_pair(LastLabel, -1));
+        SawPotentiallyThrowing = false;
+        LastEHState = -1;
+      }
+
+      if (LandingPad->WinEHState != LastEHState)
+        FuncInfo.IPToStateList.push_back(
+            std::make_pair(BeginLabel, LandingPad->WinEHState));
+      LastEHState = LandingPad->WinEHState;
+      LastLabel = LandingPad->EndLabels[P.RangeIndex];
+    }
+  }
+
+  if (ParentF != F)
+    return;
+
+  MCSymbol *UnwindMapXData = nullptr;
+  MCSymbol *TryBlockMapXData = nullptr;
+  MCSymbol *IPToStateXData = nullptr;
+  if (!FuncInfo.UnwindMap.empty())
+    UnwindMapXData = Asm->OutContext.GetOrCreateSymbol(
+        Twine("$stateUnwindMap$", ParentLinkageName));
+  if (!FuncInfo.TryBlockMap.empty())
+    TryBlockMapXData = Asm->OutContext.GetOrCreateSymbol(
+        Twine("$tryMap$", ParentLinkageName));
+  if (!FuncInfo.IPToStateList.empty())
+    IPToStateXData = Asm->OutContext.GetOrCreateSymbol(
+        Twine("$ip2state$", ParentLinkageName));
+
+  // FuncInfo {
+  //   uint32_t           MagicNumber
+  //   int32_t            MaxState;
+  //   UnwindMapEntry    *UnwindMap;
+  //   uint32_t           NumTryBlocks;
+  //   TryBlockMapEntry  *TryBlockMap;
+  //   uint32_t           IPMapEntries;
+  //   IPToStateMapEntry *IPToStateMap;
+  //   uint32_t           UnwindHelp; // (x64/ARM only)
+  //   ESTypeList        *ESTypeList;
+  //   int32_t            EHFlags;
+  // }
+  // EHFlags & 1 -> Synchronous exceptions only, no async exceptions.
+  // EHFlags & 2 -> ???
+  // EHFlags & 4 -> The function is noexcept(true), unwinding can't continue.
+  OS.EmitLabel(FuncInfoXData);
+  OS.EmitIntValue(0x19930522, 4);                      // MagicNumber
+  OS.EmitIntValue(FuncInfo.UnwindMap.size(), 4);       // MaxState
+  OS.EmitValue(createImageRel32(UnwindMapXData), 4);   // UnwindMap
+  OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4);     // NumTryBlocks
+  OS.EmitValue(createImageRel32(TryBlockMapXData), 4); // TryBlockMap
+  OS.EmitIntValue(FuncInfo.IPToStateList.size(), 4);   // IPMapEntries
+  OS.EmitValue(createImageRel32(IPToStateXData), 4);   // IPToStateMap
+  OS.EmitIntValue(FuncInfo.UnwindHelpFrameOffset, 4);  // UnwindHelp
+  OS.EmitIntValue(0, 4);                               // ESTypeList
+  OS.EmitIntValue(1, 4);                               // EHFlags
+
+  // UnwindMapEntry {
+  //   int32_t ToState;
+  //   void  (*Action)();
+  // };
+  if (UnwindMapXData) {
+    OS.EmitLabel(UnwindMapXData);
+    for (const WinEHUnwindMapEntry &UME : FuncInfo.UnwindMap) {
+      OS.EmitIntValue(UME.ToState, 4);                // ToState
+      OS.EmitValue(createImageRel32(UME.Cleanup), 4); // Action
+    }
+  }
+
+  // TryBlockMap {
+  //   int32_t      TryLow;
+  //   int32_t      TryHigh;
+  //   int32_t      CatchHigh;
+  //   int32_t      NumCatches;
+  //   HandlerType *HandlerArray;
+  // };
+  if (TryBlockMapXData) {
+    OS.EmitLabel(TryBlockMapXData);
+    SmallVector<MCSymbol *, 1> HandlerMaps;
+    for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
+      WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
+      MCSymbol *HandlerMapXData = nullptr;
+
+      if (!TBME.HandlerArray.empty())
+        HandlerMapXData =
+            Asm->OutContext.GetOrCreateSymbol(Twine("$handlerMap$")
+                                                  .concat(Twine(I))
+                                                  .concat("$")
+                                                  .concat(ParentLinkageName));
+
+      HandlerMaps.push_back(HandlerMapXData);
+
+      assert(TBME.TryLow <= TBME.TryHigh);
+      assert(TBME.CatchHigh > TBME.TryHigh);
+      OS.EmitIntValue(TBME.TryLow, 4);                    // TryLow
+      OS.EmitIntValue(TBME.TryHigh, 4);                   // TryHigh
+      OS.EmitIntValue(TBME.CatchHigh, 4);                 // CatchHigh
+      OS.EmitIntValue(TBME.HandlerArray.size(), 4);       // NumCatches
+      OS.EmitValue(createImageRel32(HandlerMapXData), 4); // HandlerArray
+    }
+
+    for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
+      WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
+      MCSymbol *HandlerMapXData = HandlerMaps[I];
+      if (!HandlerMapXData)
+        continue;
+      // HandlerType {
+      //   int32_t         Adjectives;
+      //   TypeDescriptor *Type;
+      //   int32_t         CatchObjOffset;
+      //   void          (*Handler)();
+      //   int32_t         ParentFrameOffset; // x64 only
+      // };
+      OS.EmitLabel(HandlerMapXData);
+      for (const WinEHHandlerType &HT : TBME.HandlerArray) {
+        OS.EmitIntValue(HT.Adjectives, 4);                    // Adjectives
+        OS.EmitValue(createImageRel32(HT.TypeDescriptor), 4); // Type
+        OS.EmitIntValue(0, 4);                                // CatchObjOffset
+        OS.EmitValue(createImageRel32(HT.Handler), 4);        // Handler
+        OS.EmitIntValue(0, 4);                                // ParentFrameOffset
+      }
+    }
+  }
+
+  // IPToStateMapEntry {
+  //   void   *IP;
+  //   int32_t State;
+  // };
+  if (IPToStateXData) {
+    OS.EmitLabel(IPToStateXData);
+    for (auto &IPStatePair : FuncInfo.IPToStateList) {
+      OS.EmitValue(createImageRel32(IPStatePair.first), 4); // IP
+      OS.EmitIntValue(IPStatePair.second, 4);               // State
+    }
+  }
+}