initialization calls now return argc. If the program uses the argc value

passed into main, make sure they use the return value of the init call
instead of the one passed in.

llvm-svn: 11262

1 files changed, 24 insertions, 17 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/BlockProfiling.cpp b/llvm/lib/Transforms/Instrumentation/BlockProfiling.cpp
index 7b38d70d9e3..8dacc92bc26 100644
--- a/llvm/lib/Transforms/Instrumentation/BlockProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/BlockProfiling.cpp
@@ -31,7 +31,7 @@ static void insertInitializationCall(Function *MainFn, const char *FnName,
   const Type *ArgVTy = PointerType::get(PointerType::get(Type::SByteTy));
   const Type *UIntPtr = PointerType::get(Type::UIntTy);
   Module &M = *MainFn->getParent();
-  Function *InitFn = M.getOrInsertFunction(FnName, Type::VoidTy, Type::IntTy,
+  Function *InitFn = M.getOrInsertFunction(FnName, Type::IntTy, Type::IntTy,
                                            ArgVTy, UIntPtr, Type::UIntTy, 0);
 
   // This could force argc and argv into programs that wouldn't otherwise have
@@ -45,38 +45,45 @@ static void insertInitializationCall(Function *MainFn, const char *FnName,
   BasicBlock::iterator InsertPos = Entry->begin();
   while (isa<AllocaInst>(InsertPos)) ++InsertPos;
 
+  ConstantPointerRef *ArrayCPR = ConstantPointerRef::get(Array);
+  std::vector<Constant*> GEPIndices(2, Constant::getNullValue(Type::LongTy));
+  Args[2] = ConstantExpr::getGetElementPtr(ArrayCPR, GEPIndices);
+  
+  unsigned NumElements =
+    cast<ArrayType>(Array->getType()->getElementType())->getNumElements();
+  Args[3] = ConstantUInt::get(Type::UIntTy, NumElements);
+  
+  Instruction *InitCall = new CallInst(InitFn, Args, "newargc", InsertPos);
+
+  // If argc or argv are not available in main, just pass null values in.
   Function::aiterator AI;
   switch (MainFn->asize()) {
   default:
   case 2:
     AI = MainFn->abegin(); ++AI;
     if (AI->getType() != ArgVTy) {
-      Args[1] = new CastInst(AI, ArgVTy, "argv.cast", InsertPos);
+      InitCall->setOperand(2, new CastInst(AI, ArgVTy, "argv.cast", InitCall));
     } else {
-      Args[1] = AI;
+      InitCall->setOperand(2, AI);
     }
 
   case 1:
     AI = MainFn->abegin();
+    // If the program looked at argc, have it look at the return value of the
+    // init call instead.
     if (AI->getType() != Type::IntTy) {
-      Args[0] = new CastInst(AI, Type::IntTy, "argc.cast", InsertPos);
+      if (!AI->use_empty())
+        AI->replaceAllUsesWith(new CastInst(InitCall, AI->getType(), "",
+                                            InsertPos));
+      InitCall->setOperand(1, new CastInst(AI, Type::IntTy, "argc.cast",
+                                           InitCall));
     } else {
-      Args[0] = AI;
+      AI->replaceAllUsesWith(InitCall);
+      InitCall->setOperand(1, AI);
     }
     
-  case 0:
-    break;
+  case 0: break;
   }
-
-  ConstantPointerRef *ArrayCPR = ConstantPointerRef::get(Array);
-  std::vector<Constant*> GEPIndices(2, Constant::getNullValue(Type::LongTy));
-  Args[2] = ConstantExpr::getGetElementPtr(ArrayCPR, GEPIndices);
-  
-  unsigned NumElements =
-    cast<ArrayType>(Array->getType()->getElementType())->getNumElements();
-  Args[3] = ConstantUInt::get(Type::UIntTy, NumElements);
-  
-  new CallInst(InitFn, Args, "", InsertPos);
 }
 
 static void IncrementCounterInBlock(BasicBlock *BB, unsigned CounterNum,