More work towards zero-initializing structs that contain member pointers in constant expressions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@79805 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 52 insertions, 7 deletions

diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index b3e0fef1ba..2770527eba 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -800,6 +800,14 @@ llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
       return llvm::ConstantArray::get(ATy, Array);
     }
   }
+
+  if (const RecordType *RT = T->getAs<RecordType>()) {
+    const CGRecordLayout *Layout = Types.getCGRecordLayout(RT->getDecl());
+    if (Layout->containsMemberPointer()) {
+      assert(0 && "FIXME: No support for structs with member pointers yet!");
+    }
+
+  }
   
   // FIXME: Handle structs that contain member pointers.
   if (T->isMemberPointerType()) 
diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 0dc64f009d..ea5de5f2b1 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -301,6 +301,25 @@ uint64_t CGRecordLayoutBuilder::getTypeSizeInBytes(const llvm::Type *Ty) const {
   return Types.getTargetData().getTypeAllocSize(Ty);
 }
 
+void CGRecordLayoutBuilder::CheckForMemberPointer(const FieldDecl *FD) {
+  // This record already contains a member pointer.
+  if (ContainsMemberPointer)
+    return;
+  
+  // Can only have member pointers if we're compiling C++.
+  if (!Types.getContext().getLangOptions().CPlusPlus)
+    return;
+  
+  QualType Ty = FD->getType();
+  
+  if (Ty->isMemberPointerType()) {
+    // We have a member pointer!
+    ContainsMemberPointer = true;
+    return;
+  }
+  
+}
+
 CGRecordLayout *
 CGRecordLayoutBuilder::ComputeLayout(CodeGenTypes &Types,
                                      const RecordDecl *D) {
@@ -330,5 +349,5 @@ CGRecordLayoutBuilder::ComputeLayout(CodeGenTypes &Types,
     Types.addBitFieldInfo(Info.FD, Info.FieldNo, Info.Start, Info.Size);
   }
   
-  return new CGRecordLayout(Ty);
+  return new CGRecordLayout(Ty, Builder.ContainsMemberPointer);
 }
diff --git a/lib/CodeGen/CGRecordLayoutBuilder.h b/lib/CodeGen/CGRecordLayoutBuilder.h
index ff551a4f13..63ddc10df5 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.h
+++ b/lib/CodeGen/CGRecordLayoutBuilder.h
@@ -36,6 +36,10 @@ class CGRecordLayoutBuilder {
   /// Packed - Whether the resulting LLVM struct will be packed or not.
   bool Packed;
 
+  /// ContainsMemberPointer - Whether one of the fields is a member pointer
+  /// or is a struct that contains a member pointer.
+  bool ContainsMemberPointer;
+  
   /// Alignment - Contains the alignment of the RecordDecl.
   unsigned Alignment;
 
@@ -72,7 +76,8 @@ class CGRecordLayoutBuilder {
   llvm::SmallVector<LLVMBitFieldInfo, 16> LLVMBitFields;
   
   CGRecordLayoutBuilder(CodeGenTypes &Types) 
-    : Types(Types), Packed(false), Alignment(0), AlignmentAsLLVMStruct(1)
+    : Types(Types), Packed(false), ContainsMemberPointer(false)
+    , Alignment(0), AlignmentAsLLVMStruct(1)
     , BitsAvailableInLastField(0), NextFieldOffsetInBytes(0) { }
 
   /// Layout - Will layout a RecordDecl.
@@ -113,6 +118,9 @@ class CGRecordLayoutBuilder {
   unsigned getTypeAlignment(const llvm::Type *Ty) const;
   uint64_t getTypeSizeInBytes(const llvm::Type *Ty) const;
 
+  /// CheckForMemberPointer - Check if the field contains a member pointer.
+  void CheckForMemberPointer(const FieldDecl *FD);
+  
 public:
   /// ComputeLayout - Return the right record layout for a given record decl.
   static CGRecordLayout *ComputeLayout(CodeGenTypes &Types, 
diff --git a/lib/CodeGen/CodeGenTypes.h b/lib/CodeGen/CodeGenTypes.h
index 530946bb8f..22ebbf1682 100644
--- a/lib/CodeGen/CodeGenTypes.h
+++ b/lib/CodeGen/CodeGenTypes.h
@@ -53,17 +53,27 @@ namespace CodeGen {
   /// lowering AST types to LLVM types.
   class CGRecordLayout {
     CGRecordLayout(); // DO NOT IMPLEMENT
+    
+    /// LLVMType - The LLVMType corresponding to this record layout.
+    const llvm::Type *LLVMType;
+    
+    /// ContainsMemberPointer - Whether one of the fields in this record layout
+    /// is a member pointer, or a struct that contains a member pointer.
+    bool ContainsMemberPointer;
+    
   public:
-    CGRecordLayout(const llvm::Type *T) 
-      : STy(T) { }
+    CGRecordLayout(const llvm::Type *T, bool ContainsMemberPointer) 
+      : LLVMType(T), ContainsMemberPointer(ContainsMemberPointer) { }
 
     /// getLLVMType - Return llvm type associated with this record.
     const llvm::Type *getLLVMType() const {
-      return STy;
+      return LLVMType;
     }
 
-  private:
-    const llvm::Type *STy;
+    bool containsMemberPointer() const {
+      return ContainsMemberPointer;
+    }
+    
   };
   
 /// CodeGenTypes - This class organizes the cross-module state that is used