MS ABI: Implement copy-ctor closures, finish implementing throw

This adds support for copy-constructor closures.  These are generated
when the C++ runtime has to call a copy-constructor with a particular
calling convention or with default arguments substituted in to the call.

Because the runtime has no mechanism to call the function with a
different calling convention or know-how to evaluate the default
arguments at run-time, we create a thunk which will do all the
appropriate work and package it in a way the runtime can use.

Differential Revision: http://reviews.llvm.org/D8225

llvm-svn: 231952

6 files changed, 113 insertions, 18 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 20d2aa68187..e92b33509f7 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -8210,6 +8210,18 @@ void ASTContext::addCopyConstructorForExceptionObject(CXXRecordDecl *RD,
       cast<CXXConstructorDecl>(CD->getFirstDecl()));
 }
 
+void ASTContext::addDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                                 unsigned ParmIdx, Expr *DAE) {
+  ABI->addDefaultArgExprForConstructor(
+      cast<CXXConstructorDecl>(CD->getFirstDecl()), ParmIdx, DAE);
+}
+
+Expr *ASTContext::getDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                                  unsigned ParmIdx) {
+  return ABI->getDefaultArgExprForConstructor(
+      cast<CXXConstructorDecl>(CD->getFirstDecl()), ParmIdx);
+}
+
 void ASTContext::setParameterIndex(const ParmVarDecl *D, unsigned int index) {
   ParamIndices[D] = index;
 }
diff --git a/clang/lib/AST/CXXABI.h b/clang/lib/AST/CXXABI.h
index 62c96f901e6..dad226474fa 100644
--- a/clang/lib/AST/CXXABI.h
+++ b/clang/lib/AST/CXXABI.h
@@ -21,6 +21,7 @@ namespace clang {
 
 class ASTContext;
 class CXXConstructorDecl;
+class Expr;
 class MemberPointerType;
 class MangleNumberingContext;
 
@@ -50,6 +51,12 @@ public:
   /// Retrieves the mapping from class to copy constructor for this C++ ABI.
   virtual const CXXConstructorDecl *
   getCopyConstructorForExceptionObject(CXXRecordDecl *) = 0;
+
+  virtual void addDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                               unsigned ParmIdx, Expr *DAE) = 0;
+
+  virtual Expr *getDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                                unsigned ParmIdx) = 0;
 };
 
 /// Creates an instance of a C++ ABI class.
diff --git a/clang/lib/AST/ItaniumCXXABI.cpp b/clang/lib/AST/ItaniumCXXABI.cpp
index 13d4dbf1f46..74207820b3a 100644
--- a/clang/lib/AST/ItaniumCXXABI.cpp
+++ b/clang/lib/AST/ItaniumCXXABI.cpp
@@ -141,6 +141,14 @@ public:
   void addCopyConstructorForExceptionObject(CXXRecordDecl *RD,
                                             CXXConstructorDecl *CD) override {}
 
+  void addDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                       unsigned ParmIdx, Expr *DAE) override {}
+
+  Expr *getDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                        unsigned ParmIdx) override {
+    return nullptr;
+  }
+
   MangleNumberingContext *createMangleNumberingContext() const override {
     return new ItaniumNumberingContext();
   }
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 13136b36236..f890719c209 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -3442,6 +3442,9 @@ void CXXNameMangler::mangleCXXCtorType(CXXCtorType T) {
   case Ctor_Comdat:
     Out << "C5";
     break;
+  case Ctor_DefaultClosure:
+  case Ctor_CopyingClosure:
+    llvm_unreachable("closure constructors don't exist for the Itanium ABI!");
   }
 }
 
diff --git a/clang/lib/AST/MicrosoftCXXABI.cpp b/clang/lib/AST/MicrosoftCXXABI.cpp
index 71b21bff77c..fb3beff4beb 100644
--- a/clang/lib/AST/MicrosoftCXXABI.cpp
+++ b/clang/lib/AST/MicrosoftCXXABI.cpp
@@ -64,6 +64,8 @@ public:
 class MicrosoftCXXABI : public CXXABI {
   ASTContext &Context;
   llvm::SmallDenseMap<CXXRecordDecl *, CXXConstructorDecl *> RecordToCopyCtor;
+  llvm::SmallDenseMap<std::pair<const CXXConstructorDecl *, unsigned>, Expr *>
+      CtorToDefaultArgExpr;
 
 public:
   MicrosoftCXXABI(ASTContext &Ctx) : Context(Ctx) { }
@@ -92,6 +94,16 @@ public:
       Layout.getNonVirtualSize() == PointerSize * 2;
   }
 
+  void addDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                       unsigned ParmIdx, Expr *DAE) override {
+    CtorToDefaultArgExpr[std::make_pair(CD, ParmIdx)] = DAE;
+  }
+
+  Expr *getDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
+                                        unsigned ParmIdx) override {
+    return CtorToDefaultArgExpr[std::make_pair(CD, ParmIdx)];
+  }
+
   const CXXConstructorDecl *
   getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override {
     return RecordToCopyCtor[RD];
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 073e798d11f..f56da26a09b 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -67,11 +67,15 @@ static const DeclContext *getEffectiveParentContext(const DeclContext *DC) {
   return getEffectiveDeclContext(cast<Decl>(DC));
 }
 
-static const FunctionDecl *getStructor(const FunctionDecl *fn) {
-  if (const FunctionTemplateDecl *ftd = fn->getPrimaryTemplate())
-    return ftd->getTemplatedDecl();
+static const FunctionDecl *getStructor(const NamedDecl *ND) {
+  if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(ND))
+    return FTD->getTemplatedDecl();
 
-  return fn;
+  const auto *FD = cast<FunctionDecl>(ND);
+  if (const auto *FTD = FD->getPrimaryTemplate())
+    return FTD->getTemplatedDecl();
+
+  return FD;
 }
 
 static bool isLambda(const NamedDecl *ND) {
@@ -115,7 +119,7 @@ public:
   void mangleCXXCatchableTypeArray(QualType T, uint32_t NumEntries,
                                    raw_ostream &Out) override;
   void mangleCXXCatchableType(QualType T, const CXXConstructorDecl *CD,
-                              uint32_t Size, uint32_t NVOffset,
+                              CXXCtorType CT, uint32_t Size, uint32_t NVOffset,
                               int32_t VBPtrOffset, uint32_t VBIndex,
                               raw_ostream &Out) override;
   void mangleCXXRTTI(QualType T, raw_ostream &Out) override;
@@ -224,6 +228,12 @@ public:
                          64) {}
 
   MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_,
+                          const CXXConstructorDecl *D, CXXCtorType Type)
+      : Context(C), Out(Out_), Structor(getStructor(D)), StructorType(Type),
+        PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
+                         64) {}
+
+  MicrosoftCXXNameMangler(MicrosoftMangleContextImpl &C, raw_ostream &Out_,
                           const CXXDestructorDecl *D, CXXDtorType Type)
       : Context(C), Out(Out_), Structor(getStructor(D)), StructorType(Type),
         PointersAre64Bit(C.getASTContext().getTargetInfo().getPointerWidth(0) ==
@@ -284,6 +294,7 @@ private:
   void mangleDecayedArrayType(const ArrayType *T);
   void mangleArrayType(const ArrayType *T);
   void mangleFunctionClass(const FunctionDecl *FD);
+  void mangleCallingConvention(CallingConv CC);
   void mangleCallingConvention(const FunctionType *T);
   void mangleIntegerLiteral(const llvm::APSInt &Number, bool IsBoolean);
   void mangleExpression(const Expr *E);
@@ -770,12 +781,18 @@ void MicrosoftCXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
       llvm_unreachable("Can't mangle Objective-C selector names here!");
 
     case DeclarationName::CXXConstructorName:
-      if (ND == Structor) {
-        assert(StructorType == Ctor_Complete &&
-               "Should never be asked to mangle a ctor other than complete");
+      if (Structor == getStructor(ND)) {
+        if (StructorType == Ctor_CopyingClosure) {
+          Out << "?_O";
+          return;
+        }
+        if (StructorType == Ctor_DefaultClosure) {
+          Out << "?_F";
+          return;
+        }
       }
       Out << "?0";
-      break;
+      return;
 
     case DeclarationName::CXXDestructorName:
       if (ND == Structor)
@@ -1566,12 +1583,22 @@ void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
   SourceRange Range;
   if (D) Range = D->getSourceRange();
 
-  bool IsStructor = false, HasThisQuals = ForceThisQuals;
+  bool IsStructor = false, HasThisQuals = ForceThisQuals, IsCtorClosure = false;
+  CallingConv CC = T->getCallConv();
   if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(D)) {
     if (MD->isInstance())
       HasThisQuals = true;
-    if (isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD))
+    if (isa<CXXDestructorDecl>(MD)) {
+      IsStructor = true;
+    } else if (isa<CXXConstructorDecl>(MD)) {
       IsStructor = true;
+      IsCtorClosure = (StructorType == Ctor_CopyingClosure ||
+                       StructorType == Ctor_DefaultClosure) &&
+                      getStructor(MD) == Structor;
+      if (IsCtorClosure)
+        CC = getASTContext().getDefaultCallingConvention(
+            /*IsVariadic=*/false, /*IsCXXMethod=*/true);
+    }
   }
 
   // If this is a C++ instance method, mangle the CVR qualifiers for the
@@ -1583,7 +1610,7 @@ void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
     mangleQualifiers(Quals, /*IsMember=*/false);
   }
 
-  mangleCallingConvention(T);
+  mangleCallingConvention(CC);
 
   // <return-type> ::= <type>
   //               ::= @ # structors (they have no declared return type)
@@ -1597,6 +1624,28 @@ void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
       Out << (PointersAre64Bit ? "PEAXI@Z" : "PAXI@Z");
       return;
     }
+    if (IsCtorClosure) {
+      // Default constructor closure and copy constructor closure both return
+      // void.
+      Out << 'X';
+
+      if (StructorType == Ctor_DefaultClosure) {
+        // Default constructor closure always has no arguments.
+        Out << 'X';
+      } else if (StructorType == Ctor_CopyingClosure) {
+        // Copy constructor closure always takes an unqualified reference.
+        mangleArgumentType(getASTContext().getLValueReferenceType(
+                               Proto->getParamType(0)
+                                   ->getAs<LValueReferenceType>()
+                                   ->getPointeeType(),
+                               /*SpelledAsLValue=*/true),
+                           Range);
+      } else {
+        llvm_unreachable("unexpected constructor closure!");
+      }
+      Out << "@Z";
+      return;
+    }
     Out << '@';
   } else {
     QualType ResultType = Proto->getReturnType();
@@ -1689,7 +1738,7 @@ void MicrosoftCXXNameMangler::mangleFunctionClass(const FunctionDecl *FD) {
   } else
     Out << 'Y';
 }
-void MicrosoftCXXNameMangler::mangleCallingConvention(const FunctionType *T) {
+void MicrosoftCXXNameMangler::mangleCallingConvention(CallingConv CC) {
   // <calling-convention> ::= A # __cdecl
   //                      ::= B # __export __cdecl
   //                      ::= C # __pascal
@@ -1706,7 +1755,7 @@ void MicrosoftCXXNameMangler::mangleCallingConvention(const FunctionType *T) {
   // that keyword. (It didn't actually export them, it just made them so
   // that they could be in a DLL and somebody from another module could call
   // them.)
-  CallingConv CC = T->getCallConv();
+
   switch (CC) {
     default:
       llvm_unreachable("Unsupported CC for mangling");
@@ -1720,6 +1769,9 @@ void MicrosoftCXXNameMangler::mangleCallingConvention(const FunctionType *T) {
     case CC_X86VectorCall: Out << 'Q'; break;
   }
 }
+void MicrosoftCXXNameMangler::mangleCallingConvention(const FunctionType *T) {
+  mangleCallingConvention(T->getCallConv());
+}
 void MicrosoftCXXNameMangler::mangleThrowSpecification(
                                                 const FunctionProtoType *FT) {
   // <throw-spec> ::= Z # throw(...) (default)
@@ -2310,8 +2362,9 @@ void MicrosoftMangleContextImpl::mangleCXXCatchableTypeArray(
 }
 
 void MicrosoftMangleContextImpl::mangleCXXCatchableType(
-    QualType T, const CXXConstructorDecl *CD, uint32_t Size, uint32_t NVOffset,
-    int32_t VBPtrOffset, uint32_t VBIndex, raw_ostream &Out) {
+    QualType T, const CXXConstructorDecl *CD, CXXCtorType CT, uint32_t Size,
+    uint32_t NVOffset, int32_t VBPtrOffset, uint32_t VBIndex,
+    raw_ostream &Out) {
   MicrosoftCXXNameMangler Mangler(*this, Out);
   Mangler.getStream() << "_CT";
 
@@ -2328,7 +2381,7 @@ void MicrosoftMangleContextImpl::mangleCXXCatchableType(
   llvm::SmallString<64> CopyCtorMangling;
   if (CD) {
     llvm::raw_svector_ostream Stream(CopyCtorMangling);
-    mangleCXXCtor(CD, Ctor_Complete, Stream);
+    mangleCXXCtor(CD, CT, Stream);
   }
   Mangler.getStream() << CopyCtorMangling.substr(1);
 
@@ -2411,7 +2464,7 @@ void MicrosoftMangleContextImpl::mangleTypeName(QualType T, raw_ostream &Out) {
 void MicrosoftMangleContextImpl::mangleCXXCtor(const CXXConstructorDecl *D,
                                                CXXCtorType Type,
                                                raw_ostream &Out) {
-  MicrosoftCXXNameMangler mangler(*this, Out);
+  MicrosoftCXXNameMangler mangler(*this, Out, D, Type);
   mangler.mangle(D);
 }