1 files changed, 176 insertions, 0 deletions
diff --git a/lib/CodeGen/CGCXXClass.cpp b/lib/CodeGen/CGCXXClass.cpp
new file mode 100644
index 000000000000..56a28fc9a007
--- /dev/null
+++ b/lib/CodeGen/CGCXXClass.cpp
@@ -0,0 +1,176 @@
+//===--- CGCXXClass.cpp - Emit LLVM Code for C++ classes ------------------===//
+//
+//                     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++ code generation of classes
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/RecordLayout.h"
+
+using namespace clang;
+using namespace CodeGen;
+
+static uint64_t 
+ComputeNonVirtualBaseClassOffset(ASTContext &Context, CXXBasePaths &Paths,
+                                 unsigned Start) {
+  uint64_t Offset = 0;
+
+  const CXXBasePath &Path = Paths.front();
+  for (unsigned i = Start, e = Path.size(); i != e; ++i) {
+    const CXXBasePathElement& Element = Path[i];
+
+    // Get the layout.
+    const ASTRecordLayout &Layout = Context.getASTRecordLayout(Element.Class);
+    
+    const CXXBaseSpecifier *BS = Element.Base;
+    assert(!BS->isVirtual() && "Should not see virtual bases here!");
+    
+    const CXXRecordDecl *Base = 
+      cast<CXXRecordDecl>(BS->getType()->getAs<RecordType>()->getDecl());
+    
+    // Add the offset.
+    Offset += Layout.getBaseClassOffset(Base) / 8;
+  }
+
+  return Offset;
+}
+
+llvm::Constant *
+CodeGenModule::GetCXXBaseClassOffset(const CXXRecordDecl *ClassDecl,
+                                     const CXXRecordDecl *BaseClassDecl) {
+  if (ClassDecl == BaseClassDecl)
+    return 0;
+
+  CXXBasePaths Paths(/*FindAmbiguities=*/false,
+                     /*RecordPaths=*/true, /*DetectVirtual=*/false);
+  if (!const_cast<CXXRecordDecl *>(ClassDecl)->
+        isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClassDecl), Paths)) {
+    assert(false && "Class must be derived from the passed in base class!");
+    return 0;
+  }
+
+  uint64_t Offset = ComputeNonVirtualBaseClassOffset(getContext(), Paths, 0);
+  if (!Offset)
+    return 0;
+
+  const llvm::Type *PtrDiffTy = 
+    Types.ConvertType(getContext().getPointerDiffType());
+
+  return llvm::ConstantInt::get(PtrDiffTy, Offset);
+}
+
+static llvm::Value *GetCXXBaseClassOffset(CodeGenFunction &CGF,
+                                          llvm::Value *BaseValue,
+                                          const CXXRecordDecl *ClassDecl,
+                                          const CXXRecordDecl *BaseClassDecl) {
+  CXXBasePaths Paths(/*FindAmbiguities=*/false,
+                     /*RecordPaths=*/true, /*DetectVirtual=*/true);
+  if (!const_cast<CXXRecordDecl *>(ClassDecl)->
+        isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClassDecl), Paths)) {
+    assert(false && "Class must be derived from the passed in base class!");
+    return 0;
+  }
+
+  unsigned Start = 0;
+  llvm::Value *VirtualOffset = 0;
+  if (const RecordType *RT = Paths.getDetectedVirtual()) {
+    const CXXRecordDecl *VBase = cast<CXXRecordDecl>(RT->getDecl());
+    
+    VirtualOffset = 
+      CGF.GetVirtualCXXBaseClassOffset(BaseValue, ClassDecl, VBase);
+    
+    const CXXBasePath &Path = Paths.front();
+    unsigned e = Path.size();
+    for (Start = 0; Start != e; ++Start) {
+      const CXXBasePathElement& Element = Path[Start];
+      
+      if (Element.Class == VBase)
+        break;
+    }
+  }
+  
+  uint64_t Offset = 
+    ComputeNonVirtualBaseClassOffset(CGF.getContext(), Paths, Start);
+  
+  if (!Offset)
+    return VirtualOffset;
+  
+  const llvm::Type *PtrDiffTy = 
+    CGF.ConvertType(CGF.getContext().getPointerDiffType());
+  llvm::Value *NonVirtualOffset = llvm::ConstantInt::get(PtrDiffTy, Offset);
+  
+  if (VirtualOffset)
+    return CGF.Builder.CreateAdd(VirtualOffset, NonVirtualOffset);
+                    
+  return NonVirtualOffset;
+}
+
+llvm::Value *
+CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
+                                          const CXXRecordDecl *ClassDecl,
+                                          const CXXRecordDecl *BaseClassDecl,
+                                          bool NullCheckValue) {
+  QualType BTy =
+    getContext().getCanonicalType(
+      getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(BaseClassDecl)));
+  const llvm::Type *BasePtrTy = llvm::PointerType::getUnqual(ConvertType(BTy));
+
+  if (ClassDecl == BaseClassDecl) {
+    // Just cast back.
+    return Builder.CreateBitCast(BaseValue, BasePtrTy);
+  }
+  
+  llvm::BasicBlock *CastNull = 0;
+  llvm::BasicBlock *CastNotNull = 0;
+  llvm::BasicBlock *CastEnd = 0;
+  
+  if (NullCheckValue) {
+    CastNull = createBasicBlock("cast.null");
+    CastNotNull = createBasicBlock("cast.notnull");
+    CastEnd = createBasicBlock("cast.end");
+    
+    llvm::Value *IsNull = 
+      Builder.CreateICmpEQ(BaseValue,
+                           llvm::Constant::getNullValue(BaseValue->getType()));
+    Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
+    EmitBlock(CastNotNull);
+  }
+  
+  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
+
+  llvm::Value *Offset = 
+    GetCXXBaseClassOffset(*this, BaseValue, ClassDecl, BaseClassDecl);
+  
+  if (Offset) {
+    // Apply the offset.
+    BaseValue = Builder.CreateBitCast(BaseValue, Int8PtrTy);
+    BaseValue = Builder.CreateGEP(BaseValue, Offset, "add.ptr");
+  }
+  
+  // Cast back.
+  BaseValue = Builder.CreateBitCast(BaseValue, BasePtrTy);
+ 
+  if (NullCheckValue) {
+    Builder.CreateBr(CastEnd);
+    EmitBlock(CastNull);
+    Builder.CreateBr(CastEnd);
+    EmitBlock(CastEnd);
+    
+    llvm::PHINode *PHI = Builder.CreatePHI(BaseValue->getType());
+    PHI->reserveOperandSpace(2);
+    PHI->addIncoming(BaseValue, CastNotNull);
+    PHI->addIncoming(llvm::Constant::getNullValue(BaseValue->getType()), 
+                     CastNull);
+    BaseValue = PHI;
+  }
+  
+  return BaseValue;
+}