Whoops, add CGCXXClass.cpp

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81607 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 104 insertions, 0 deletions

diff --git a/lib/CodeGen/CGCXXClass.cpp b/lib/CodeGen/CGCXXClass.cpp
new file mode 100644
index 0000000000..1fb8f8308c
--- /dev/null
+++ b/lib/CodeGen/CGCXXClass.cpp
@@ -0,0 +1,104 @@
+//===--- 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/RecordLayout.h"
+using namespace clang;
+using namespace CodeGen;
+
+static bool
+GetNestedPaths(llvm::SmallVectorImpl<const CXXRecordDecl *> &NestedBasePaths,
+               const CXXRecordDecl *ClassDecl,
+               const CXXRecordDecl *BaseClassDecl) {
+  for (CXXRecordDecl::base_class_const_iterator i = ClassDecl->bases_begin(),
+      e = ClassDecl->bases_end(); i != e; ++i) {
+    if (i->isVirtual())
+      continue;
+    const CXXRecordDecl *Base =
+      cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
+    if (Base == BaseClassDecl) {
+      NestedBasePaths.push_back(BaseClassDecl);
+      return true;
+    }
+  }
+  // BaseClassDecl not an immediate base of ClassDecl.
+  for (CXXRecordDecl::base_class_const_iterator i = ClassDecl->bases_begin(),
+       e = ClassDecl->bases_end(); i != e; ++i) {
+    if (i->isVirtual())
+      continue;
+    const CXXRecordDecl *Base =
+      cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
+    if (GetNestedPaths(NestedBasePaths, Base, BaseClassDecl)) {
+      NestedBasePaths.push_back(Base);
+      return true;
+    }
+  }
+  return false;
+}
+
+static uint64_t ComputeBaseClassOffset(ASTContext &Context,
+                                       const CXXRecordDecl *ClassDecl,
+                                       const CXXRecordDecl *BaseClassDecl) {
+    uint64_t Offset = 0;
+
+    llvm::SmallVector<const CXXRecordDecl *, 16> NestedBasePaths;
+    GetNestedPaths(NestedBasePaths, ClassDecl, BaseClassDecl);
+    assert(NestedBasePaths.size() > 0 &&
+           "AddressCXXOfBaseClass - inheritence path failed");
+    NestedBasePaths.push_back(ClassDecl);
+    
+    for (unsigned i = NestedBasePaths.size() - 1; i > 0; i--) {
+        const CXXRecordDecl *DerivedClass = NestedBasePaths[i];
+        const CXXRecordDecl *BaseClass = NestedBasePaths[i-1];
+        const ASTRecordLayout &Layout = 
+            Context.getASTRecordLayout(DerivedClass);
+        
+        Offset += Layout.getBaseClassOffset(BaseClass) / 8;
+    }
+    
+    return Offset;
+}
+
+llvm::Value *
+CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
+                                          const CXXRecordDecl *ClassDecl,
+                                          const CXXRecordDecl *BaseClassDecl,
+                                          bool NullCheckValue) {
+  if (ClassDecl == BaseClassDecl)
+    return BaseValue;
+
+
+  uint64_t Offset = ComputeBaseClassOffset(getContext(), 
+                                           ClassDecl, BaseClassDecl);
+
+  const llvm::Type *LongTy = 
+    CGM.getTypes().ConvertType(CGM.getContext().LongTy);
+  const llvm::Type *Int8PtrTy = 
+    llvm::PointerType::getUnqual(llvm::Type::getInt8Ty(VMContext));
+  
+  llvm::Value *OffsetVal = llvm::ConstantInt::get(LongTy, Offset);
+  
+  // Apply the offset.
+  BaseValue = Builder.CreateBitCast(BaseValue, Int8PtrTy);
+  BaseValue = Builder.CreateGEP(BaseValue, OffsetVal, "add.ptr");
+  
+  QualType BTy =
+    getContext().getCanonicalType(
+      getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(BaseClassDecl)));
+  
+  // Cast back.
+  const llvm::Type *BasePtr = llvm::PointerType::getUnqual(ConvertType(BTy));
+  BaseValue = Builder.CreateBitCast(BaseValue, BasePtr);
+  
+  return BaseValue;
+}