X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FDwarfEHPrepare.cpp;h=39fc85e7649eb81f9dbd6d73b5d6aac858a93909;hb=3b131d7cc4dc4bbb329c136705b37dc255995fbd;hp=5bfb32870c9801ebf816544c9779cca9039675bc;hpb=debcb01b0f0a15f568ca69e8f288fade4bfc7297;p=oota-llvm.git

diff --git a/lib/CodeGen/DwarfEHPrepare.cpp b/lib/CodeGen/DwarfEHPrepare.cpp
index 5bfb32870c9..39fc85e7649 100644
--- a/lib/CodeGen/DwarfEHPrepare.cpp
+++ b/lib/CodeGen/DwarfEHPrepare.cpp
@@ -21,7 +21,7 @@
 #include "llvm/IntrinsicInst.h"
 #include "llvm/Module.h"
 #include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/PromoteMemToReg.h"
@@ -33,7 +33,7 @@ STATISTIC(NumExceptionValuesMoved, "Number of eh.exception calls moved");
 STATISTIC(NumStackTempsIntroduced, "Number of stack temporaries introduced");
 
 namespace {
-  class VISIBILITY_HIDDEN DwarfEHPrepare : public FunctionPass {
+  class DwarfEHPrepare : public FunctionPass {
     const TargetLowering *TLI;
     bool CompileFast;
 
@@ -107,12 +107,17 @@ FunctionPass *llvm::createDwarfEHPass(const TargetLowering *tli, bool fast) {
 
 /// NormalizeLandingPads - Normalize and discover landing pads, noting them
 /// in the LandingPads set.  A landing pad is normal if the only CFG edges
-/// that end at it are unwind edges from invoke instructions.
+/// that end at it are unwind edges from invoke instructions. If we inlined
+/// through an invoke we could have a normal branch from the previous
+/// unwind block through to the landing pad for the original invoke.
 /// Abnormal landing pads are fixed up by redirecting all unwind edges to
 /// a new basic block which falls through to the original.
 bool DwarfEHPrepare::NormalizeLandingPads() {
   bool Changed = false;
 
+  const MCAsmInfo *MAI = TLI->getTargetMachine().getMCAsmInfo();
+  bool usingSjLjEH = MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
+
   for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
     TerminatorInst *TI = I->getTerminator();
     if (!isa<InvokeInst>(TI))
@@ -124,14 +129,24 @@ bool DwarfEHPrepare::NormalizeLandingPads() {
 
     // Check that only invoke unwind edges end at the landing pad.
     bool OnlyUnwoundTo = true;
+    bool SwitchOK = usingSjLjEH;
     for (pred_iterator PI = pred_begin(LPad), PE = pred_end(LPad);
          PI != PE; ++PI) {
       TerminatorInst *PT = (*PI)->getTerminator();
+      // The SjLj dispatch block uses a switch instruction. This is effectively
+      // an unwind edge, so we can disregard it here. There will only ever
+      // be one dispatch, however, so if there are multiple switches, one
+      // of them truly is a normal edge, not an unwind edge.
+      if (SwitchOK && isa<SwitchInst>(PT)) {
+        SwitchOK = false;
+        continue;
+      }
       if (!isa<InvokeInst>(PT) || LPad == PT->getSuccessor(0)) {
         OnlyUnwoundTo = false;
         break;
       }
     }
+
     if (OnlyUnwoundTo) {
       // Only unwind edges lead to the landing pad.  Remember the landing pad.
       LandingPads.insert(LPad);
@@ -142,7 +157,8 @@ bool DwarfEHPrepare::NormalizeLandingPads() {
     // edges to a new basic block which falls through into this one.
 
     // Create the new basic block.
-    BasicBlock *NewBB = BasicBlock::Create(LPad->getName() + "_unwind_edge");
+    BasicBlock *NewBB = BasicBlock::Create(F->getContext(),
+                                           LPad->getName() + "_unwind_edge");
 
     // Insert it into the function right before the original landing pad.
     LPad->getParent()->getBasicBlockList().insert(LPad, NewBB);
@@ -218,28 +234,43 @@ bool DwarfEHPrepare::NormalizeLandingPads() {
 /// at runtime if there is no such exception: using unwind to throw a new
 /// exception is currently not supported.
 bool DwarfEHPrepare::LowerUnwinds() {
-  bool Changed = false;
+  SmallVector<TerminatorInst*, 16> UnwindInsts;
 
   for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
     TerminatorInst *TI = I->getTerminator();
-    if (!isa<UnwindInst>(TI))
-      continue;
+    if (isa<UnwindInst>(TI))
+      UnwindInsts.push_back(TI);
+  }
+
+  if (UnwindInsts.empty()) return false;
+
+  // Find the rewind function if we didn't already.
+  if (!RewindFunction) {
+    LLVMContext &Ctx = UnwindInsts[0]->getContext();
+    std::vector<const Type*>
+      Params(1, Type::getInt8PtrTy(Ctx));
+    FunctionType *FTy = FunctionType::get(Type::getVoidTy(Ctx),
+                                          Params, false);
+    const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
+    RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
+  }
+
+  bool Changed = false;
+
+  for (SmallVectorImpl<TerminatorInst*>::iterator
+         I = UnwindInsts.begin(), E = UnwindInsts.end(); I != E; ++I) {
+    TerminatorInst *TI = *I;
 
     // Replace the unwind instruction with a call to _Unwind_Resume (or the
     // appropriate target equivalent) followed by an UnreachableInst.
 
-    // Find the rewind function if we didn't already.
-    if (!RewindFunction) {
-      std::vector<const Type*> Params(1, PointerType::getUnqual(Type::Int8Ty));
-      FunctionType *FTy = FunctionType::get(Type::VoidTy, Params, false);
-      const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
-      RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
-    }
-
     // Create the call...
-    CallInst::Create(RewindFunction, CreateReadOfExceptionValue(I), "", TI);
+    CallInst *CI = CallInst::Create(RewindFunction,
+                                    CreateReadOfExceptionValue(TI->getParent()),
+                                    "", TI);
+    CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
     // ...followed by an UnreachableInst.
-    new UnreachableInst(TI);
+    new UnreachableInst(TI->getContext(), TI);
 
     // Nuke the unwind instruction.
     TI->eraseFromParent();
@@ -314,7 +345,7 @@ bool DwarfEHPrepare::PromoteStackTemporaries() {
   if (ExceptionValueVar && DT && DF && isAllocaPromotable(ExceptionValueVar)) {
     // Turn the exception temporary into registers and phi nodes if possible.
     std::vector<AllocaInst*> Allocas(1, ExceptionValueVar);
-    PromoteMemToReg(Allocas, *DT, *DF, ExceptionValueVar->getContext());
+    PromoteMemToReg(Allocas, *DT, *DF);
     return true;
   }
   return false;
@@ -354,8 +385,8 @@ Instruction *DwarfEHPrepare::CreateValueLoad(BasicBlock *BB) {
 
   // Create the temporary if we didn't already.
   if (!ExceptionValueVar) {
-    ExceptionValueVar = new AllocaInst(PointerType::getUnqual(Type::Int8Ty),
-                                       "eh.value", F->begin()->begin());
+    ExceptionValueVar = new AllocaInst(PointerType::getUnqual(
+           Type::getInt8Ty(BB->getContext())), "eh.value", F->begin()->begin());
     ++NumStackTempsIntroduced;
   }