From: Anders Carlsson <andersca@mac.com>
Date: Sat, 3 Oct 2009 15:02:02 +0000 (+0000)
Subject: Handle members to function pointers in CGExprConstant.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f57b4e44d03266f2ec1b427645555ed8952bc830;p=clang

Handle members to function pointers in CGExprConstant.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83264 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index c67b41f4e2..144fa28e19 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -402,7 +402,50 @@ public:
   llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E) {
     return Visit(E->getInitializer());
   }
+  
+  llvm::Constant *EmitMemberFunctionPointer(CXXMethodDecl *MD) {
+    assert(MD->isInstance() && "Member function must not be static!");
+    
+    const llvm::Type *PtrDiffTy = 
+      CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
+    
+    llvm::Constant *Values[2];
+    
+    // Get the function pointer (or index if this is a virtual function).
+    if (MD->isVirtual()) {
+      uint64_t Index = CGM.GetVtableIndex(MD);
+      
+      Values[0] = llvm::ConstantInt::get(PtrDiffTy, Index + 1);
+    } else {
+      llvm::Constant *FuncPtr = CGM.GetAddrOfFunction(MD);
+
+      Values[0] = llvm::ConstantExpr::getPtrToInt(FuncPtr, PtrDiffTy);
+    } 
+    
+    // The adjustment will always be 0.
+    Values[1] = llvm::ConstantInt::get(PtrDiffTy, 0);
+    
+    return llvm::ConstantStruct::get(CGM.getLLVMContext(),
+                                     Values, 2, /*Packed=*/false);
+  }
 
+  llvm::Constant *VisitUnaryAddrOf(UnaryOperator *E) {
+    if (const MemberPointerType *MPT = 
+        E->getType()->getAs<MemberPointerType>()) {
+      QualType T = MPT->getPointeeType();
+      if (T->isFunctionProtoType()) {
+        QualifiedDeclRefExpr *DRE = cast<QualifiedDeclRefExpr>(E->getSubExpr());
+        
+        return EmitMemberFunctionPointer(cast<CXXMethodDecl>(DRE->getDecl()));
+      }
+      
+      // FIXME: Should we handle other member pointer types here too,
+      // or should they be handled by Expr::Evaluate?
+    }
+    
+    return 0;
+  }
+    
   llvm::Constant *VisitCastExpr(CastExpr* E) {
     switch (E->getCastKind()) {
     case CastExpr::CK_ToUnion: {
diff --git a/test/CodeGenCXX/member-function-pointers.cpp b/test/CodeGenCXX/member-function-pointers.cpp
index bf24aea9fc..38c13d2919 100644
--- a/test/CodeGenCXX/member-function-pointers.cpp
+++ b/test/CodeGenCXX/member-function-pointers.cpp
@@ -1,7 +1,7 @@
 // RUN: clang-cc %s -emit-llvm -o - -triple=x86_64-apple-darwin9 | FileCheck %s
 
-struct A { int a; };
-struct B { int b; };
+struct A { int a; void f(); virtual void vf(); };
+struct B { int b; virtual void g(); };
 struct C : B, A { };
 
 void (A::*pa)();
@@ -9,6 +9,12 @@ void (A::*volatile vpa)();
 void (B::*pb)();
 void (C::*pc)();
 
+// CHECK: @pa2 = global %0 { i64 ptrtoint (void ()* @_ZN1A1fEv to i64), i64 0 }, align 8
+void (A::*pa2)() = &A::f;
+
+// CHECK: @pa3 = global %0 { i64 1, i64 0 }, align 8
+void (A::*pa3)() = &A::vf;
+
 void f() {
   // CHECK: store i64 0, i64* getelementptr inbounds (%0* @pa, i32 0, i32 0)
   // CHECK: store i64 0, i64* getelementptr inbounds (%0* @pa, i32 0, i32 1)
@@ -19,7 +25,7 @@ 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, 4
+  // 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;  
+  pc = pa;
 }