1 files changed, 105 insertions, 0 deletions
diff --git a/lib/CodeGen/CGException.cpp b/lib/CodeGen/CGException.cpp
new file mode 100644
index 000000000000..adfd0055f936
--- /dev/null
+++ b/lib/CodeGen/CGException.cpp
@@ -0,0 +1,105 @@
+//===--- CGException.cpp - Emit LLVM Code for C++ exceptions --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code dealing with C++ exception related code generation.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+using namespace clang;
+using namespace CodeGen;
+
+static llvm::Constant *getAllocateExceptionFn(CodeGenFunction &CGF) {
+  // void *__cxa_allocate_exception(size_t thrown_size);
+  const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
+  std::vector<const llvm::Type*> Args(1, SizeTy);
+  
+  const llvm::FunctionType *FTy = 
+  llvm::FunctionType::get(llvm::Type::getInt8PtrTy(CGF.getLLVMContext()),
+                          Args, false);
+  
+  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception");
+}
+
+static llvm::Constant *getThrowFn(CodeGenFunction &CGF) {
+  // void __cxa_throw (void *thrown_exception, std::type_info *tinfo, 
+  //                   void (*dest) (void *) );
+
+  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
+  std::vector<const llvm::Type*> Args(3, Int8PtrTy);
+  
+  const llvm::FunctionType *FTy = 
+  llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
+                          Args, false);
+  
+  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_throw");
+}
+
+void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
+  // FIXME: Handle rethrows.
+  if (!E->getSubExpr()) {
+    ErrorUnsupported(E, "rethrow expression");
+    return;
+  }
+  
+  QualType ThrowType = E->getSubExpr()->getType();
+  // FIXME: We only handle non-class types for now.
+  if (ThrowType->isRecordType()) {
+    ErrorUnsupported(E, "throw expression");
+    return;
+  }
+
+  // FIXME: Handle cleanup.
+  if (!CleanupEntries.empty()){
+    ErrorUnsupported(E, "throw expression");
+    return;
+  }
+  
+  // Now allocate the exception object.
+  const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
+  uint64_t TypeSize = getContext().getTypeSize(ThrowType) / 8;
+  
+  llvm::Constant *AllocExceptionFn = getAllocateExceptionFn(*this);
+  llvm::Value *ExceptionPtr = 
+    Builder.CreateCall(AllocExceptionFn, 
+                       llvm::ConstantInt::get(SizeTy, TypeSize),
+                       "exception");
+
+  // Store the throw exception in the exception object.
+  if (!hasAggregateLLVMType(ThrowType)) {
+    llvm::Value *Value = EmitScalarExpr(E->getSubExpr());
+    const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo(0);
+    
+    Builder.CreateStore(Value, Builder.CreateBitCast(ExceptionPtr, ValuePtrTy));
+  } else {
+    // FIXME: Handle complex and aggregate expressions.
+    ErrorUnsupported(E, "throw expression");
+  }
+  
+  // Now throw the exception.
+  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
+  
+  llvm::SmallString<256> OutName;
+  llvm::raw_svector_ostream Out(OutName);
+  mangleCXXRtti(CGM.getMangleContext(), ThrowType, Out);
+  
+  // FIXME: Is it OK to use CreateRuntimeVariable for this?
+  llvm::Constant *TypeInfo = 
+    CGM.CreateRuntimeVariable(llvm::Type::getInt8Ty(getLLVMContext()),
+                              OutName.c_str());
+  llvm::Constant *Dtor = llvm::Constant::getNullValue(Int8PtrTy);
+  
+  llvm::CallInst *ThrowCall = 
+    Builder.CreateCall3(getThrowFn(*this), ExceptionPtr, TypeInfo, Dtor);
+  ThrowCall->setDoesNotReturn();
+  Builder.CreateUnreachable();
+  
+  // Clear the insertion point to indicate we are in unreachable code.
+  Builder.ClearInsertionPoint();
+}