Handle simple struct member expr.

llvm-svn: 43258

clang/CodeGen/CGExpr.cpp

@@ -101,6 +101,7 @@ LValue CodeGenFunction::EmitLValue(const Expr *E) {
     return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
   case Expr::OCUVectorElementExprClass:
     return EmitOCUVectorElementExpr(cast<OCUVectorElementExpr>(E));
+  case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
   }
 }
 
@@ -381,6 +382,36 @@ EmitOCUVectorElementExpr(const OCUVectorElementExpr *E) {
                                   E->getEncodedElementAccess());
 }
 
+LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
+
+  // FIXME: Handle union members.
+  if (E->getBase()->getType()->getAsUnionType()) {
+    fprintf(stderr, "Unimplemented lvalue expr!\n");
+    E->dump(getContext().SourceMgr);
+    llvm::Type *Ty = llvm::PointerType::get(ConvertType(E->getType()));
+    return LValue::MakeAddr(llvm::UndefValue::get(Ty));
+  }
+  
+  LValue BaseLV = EmitLValue(E->getBase());
+  llvm::Value *BaseValue = BaseLV.getAddress();
+
+  FieldDecl *Field = E->getMemberDecl();
+  unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
+  llvm::Value *Idxs[2] = { llvm::Constant::getNullValue(llvm::Type::Int32Ty), 
+			   llvm::ConstantInt::get(llvm::Type::Int32Ty, idx) };
+  if (E->isArrow()) {
+    QualType PTy = cast<PointerType>(E->getBase()->getType())->getPointeeType();
+    BaseValue =  Builder.CreateBitCast(BaseValue, 
+				       llvm::PointerType::get(ConvertType(PTy)),
+				       "tmp");
+  }
+
+  return LValue::MakeAddr(Builder.CreateGEP(BaseValue,Idxs, Idxs + 2, "tmp"));
+  
+  // FIXME: If record field does not have one to one match with llvm::StructType
+  // field then apply appropriate masks to select only member field bits.
+}
+
 //===--------------------------------------------------------------------===//
 //                             Expression Emission
 //===--------------------------------------------------------------------===//

clang/test/CodeGen/struct.c

+// RUN: clang %s -emit-llvm
+
+struct  {
+  int x;
+  int y;
+} point;
+
+void fn1() {
+  point.x = 42;
+}
+
+/* Nested member */
+struct  {
+  struct {
+    int a;
+    int b;
+  } p1;
+} point2;
+
+void fn2() {
+  point2.p1.a = 42;
+}
+
+/* Indirect reference */
+typedef struct __sf {
+ unsigned char *c;
+ short flags;
+} F;
+
+typedef struct __sf2 {
+  F *ff;
+} F2;
+
+int fn3(F2 *c) {
+  if (c->ff->c >= 0)
+    return 1;
+  else
+    return 0;
+}