From c46bf276e17a9e88f220cb4a40cdfce7fdd3e53f Mon Sep 17 00:00:00 2001
From: Anders Carlsson <andersca@mac.com>
Date: Sat, 3 Oct 2009 15:43:24 +0000
Subject: [PATCH] Teach AggExprEmitter about pointers to member functions.

llvm-svn: 83266
---
 clang/lib/CodeGen/CGExprAgg.cpp               | 33 +++++++++++++++++++
 .../CodeGenCXX/member-function-pointers.cpp   | 16 ++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 5307d147538c..1dd97d6a228b 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -94,6 +94,7 @@ public:
   void VisitBinaryOperator(const BinaryOperator *BO);
   void VisitBinAssign(const BinaryOperator *E);
   void VisitBinComma(const BinaryOperator *E);
+  void VisitUnaryAddrOf(const UnaryOperator *E);
 
   void VisitObjCMessageExpr(ObjCMessageExpr *E);
   void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) {
@@ -281,6 +282,38 @@ void AggExprEmitter::VisitBinComma(const BinaryOperator *E) {
                   /*IgnoreResult=*/false, IsInitializer);
 }
 
+void AggExprEmitter::VisitUnaryAddrOf(const UnaryOperator *E) {
+  // We have a member function pointer.
+  const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>();
+  assert(MPT->getPointeeType()->isFunctionProtoType() &&
+         "Unexpected member pointer type!");
+  
+  const QualifiedDeclRefExpr *DRE = cast<QualifiedDeclRefExpr>(E->getSubExpr());
+  const CXXMethodDecl *MD = cast<CXXMethodDecl>(DRE->getDecl());
+
+  const llvm::Type *PtrDiffTy = 
+    CGF.ConvertType(CGF.getContext().getPointerDiffType());
+
+  llvm::Value *DstPtr = Builder.CreateStructGEP(DestPtr, 0, "dst.ptr");
+  llvm::Value *FuncPtr;
+  
+  if (MD->isVirtual()) {
+    uint64_t Index = CGF.CGM.GetVtableIndex(MD);
+    
+    FuncPtr = llvm::ConstantInt::get(PtrDiffTy, Index + 1);
+  } else {
+    FuncPtr = llvm::ConstantExpr::getPtrToInt(CGF.CGM.GetAddrOfFunction(MD), 
+                                              PtrDiffTy);
+  }
+  Builder.CreateStore(FuncPtr, DstPtr, VolatileDest);
+
+  llvm::Value *AdjPtr = Builder.CreateStructGEP(DestPtr, 1, "dst.adj");
+  
+  // The adjustment will always be 0.
+  Builder.CreateStore(llvm::ConstantInt::get(PtrDiffTy, 0), AdjPtr,
+                      VolatileDest);
+}
+
 void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) {
   CGF.EmitCompoundStmt(*E->getSubStmt(), true, DestPtr, VolatileDest);
 }
diff --git a/clang/test/CodeGenCXX/member-function-pointers.cpp b/clang/test/CodeGenCXX/member-function-pointers.cpp
index 138ba173a3e6..57e2e7f2d6c6 100644
--- a/clang/test/CodeGenCXX/member-function-pointers.cpp
+++ b/clang/test/CodeGenCXX/member-function-pointers.cpp
@@ -31,7 +31,21 @@ void f() {
   vpa = 0;
 
   // CHECK: store i64 %0, i64* getelementptr inbounds (%0* @pc, i32 0, i32 0)
-  // CHECK: [[ADJ:%[a-zA-Z0-9]+]] = add i64 %1, 16
+  // CHECK: [[ADJ:%[a-zA-Z0-9\.]+]] = add i64 %1, 16
   // CHECK: store i64 [[ADJ]], i64* getelementptr inbounds (%0* @pc, i32 0, i32 1)
   pc = pa;
 }
+
+void f2() {
+  // CHECK: [[pa2ptr:%[a-zA-Z0-9\.]+]] = getelementptr inbounds %0* %pa2, i32 0, i32 0 
+  // CHECK: store i64 ptrtoint (void ()* @_ZN1A1fEv to i64), i64* [[pa2ptr]]
+  // CHECK: [[pa2adj:%[a-zA-Z0-9\.]+]] = getelementptr inbounds %0* %pa2, i32 0, i32 1
+  // CHECK: store i64 0, i64* [[pa2adj]]
+  void (A::*pa2)() = &A::f;
+  
+  // CHECK: [[pa3ptr:%[a-zA-Z0-9\.]+]] = getelementptr inbounds %0* %pa3, i32 0, i32 0 
+  // CHECK: store i64 1, i64* [[pa3ptr]]
+  // CHECK: [[pa3adj:%[a-zA-Z0-9\.]+]] = getelementptr inbounds %0* %pa3, i32 0, i32 1
+  // CHECK: store i64 0, i64* [[pa2adj]]
+  void (A::*pa3)() = &A::vf;
+}