Patch for synthesizing copy assignment operator.
WIP.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@78841 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index f161f9f..b65c6b3 100644
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -902,6 +902,32 @@
   FinishFunction();
 }  
 
+/// SynthesizeCXXCopyAssignment - Implicitly define copy assignment operator.
+/// Before the implicitly-declared copy assignment operator for a class is 
+/// implicitly defined, all implicitly- declared copy assignment operators for 
+/// its direct base classes and its nonstatic data members shall have been 
+/// implicitly defined. [12.8-p12]
+/// The implicitly-defined copy assignment operator for class X performs 
+/// memberwise assignment of its subob- jects. The direct base classes of X are 
+/// assigned first, in the order of their declaration in 
+/// the base-specifier-list, and then the immediate nonstatic data members of X 
+/// are assigned, in the order in which they were declared in the class 
+/// definition.Each subobject is assigned in the manner appropriate to its type:
+/// — if the subobject is of class type, the copy assignment operator for the 
+///   class is used (as if by explicit qual- ification; that is, ignoring any 
+///   possible virtual overriding functions in more derived classes);
+/// — if the subobject is an array, each element is assigned, in the manner 
+///   appropriate to the element type;
+/// — if the subobject is of scalar type, the built-in assignment operator is 
+///   used.
+void CodeGenFunction::SynthesizeCXXCopyAssignment(const CXXMethodDecl *CD,
+                                                  const FunctionDecl *FD,
+                                                  llvm::Function *Fn,
+                                                  const FunctionArgList &Args) {
+  StartFunction(FD, FD->getResultType(), Fn, Args, SourceLocation());
+  
+  FinishFunction();
+}  
 
 /// EmitCtorPrologue - This routine generates necessary code to initialize
 /// base classes and non-static data members belonging to this constructor.
diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 309c76b..b7ae7c1 100644
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -254,6 +254,9 @@
         SynthesizeDefaultConstructor(CD, FD, Fn, Args);
       }
     }
+  else if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
+         if (MD->isCopyAssignment())
+           SynthesizeCXXCopyAssignment(MD, FD, Fn, Args);
     
   // Destroy the 'this' declaration.
   if (CXXThisDecl)
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index ece4f10..226c272 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -374,6 +374,12 @@
                                     const FunctionDecl *FD,
                                     llvm::Function *Fn,
                                     const FunctionArgList &Args);
+  
+  void SynthesizeCXXCopyAssignment(const CXXMethodDecl *CD,
+                                   const FunctionDecl *FD,
+                                   llvm::Function *Fn,
+                                   const FunctionArgList &Args);
+  
   void SynthesizeDefaultConstructor(const CXXConstructorDecl *CD,
                                     const FunctionDecl *FD,
                                     llvm::Function *Fn,
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index a642de9..22737a4 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -653,6 +653,11 @@
       else if (!ClassDecl->hasUserDeclaredConstructor())
         DeferredDeclsToEmit.push_back(D);
     }
+    else 
+      if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
+        if (MD->isCopyAssignment()) {
+          DeferredDeclsToEmit.push_back(D);
+        }
   }
   
   // This function doesn't have a complete type (for example, the return