[llvm-commits] [llvm] r81785 - /llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp

[Bill Wendling]

Author: void
Date: Mon Sep 14 15:52:37 2009
New Revision: 81785

URL: http://llvm.org/viewvc/llvm-project?rev=81785&view=rev
Log:
Pull the creation of the "RewindFunction" function out of the loop. It's only
created once, so shouldn't be stuck in the middle of the loop. Also early exit
if there are no uses of UnwindInst in the function.

Modified:
    llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp

Modified: llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp?rev=81785&r1=81784&r2=81785&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/DwarfEHPrepare.cpp Mon Sep 14 15:52:37 2009
@@ -219,29 +219,40 @@
 /// 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, PointerType::getUnqual(Type::getInt8Ty(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::getInt8Ty(TI->getContext())));
-      FunctionType *FTy = FunctionType::get(Type::getVoidTy(TI->getContext()),
-                                            Params, false);
-      const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
-      RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
-    }
-
     // Create the call...
     CallInst *CI = CallInst::Create(RewindFunction,
-				    CreateReadOfExceptionValue(I), "", TI);
+				    CreateReadOfExceptionValue(TI->getParent()),
+                                    "", TI);
     CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
     // ...followed by an UnreachableInst.
     new UnreachableInst(TI->getContext(), TI);