Encoding calling conventions in the type system, from Charles Davis!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@93726 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 127 insertions, 42 deletions

diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
index 5db8e20e7e..2d151ff83a 100644
--- a/include/clang/AST/ASTContext.h
+++ b/include/clang/AST/ASTContext.h
@@ -397,6 +397,11 @@ public:
   /// BlockPointer.
   QualType getNoReturnType(QualType T, bool AddNoReturn = true);
 
+  /// getCallConvType - Adds the specified calling convention attribute to
+  /// the given type, which must be a FunctionType or a pointer to an
+  /// allowable type.
+  QualType getCallConvType(QualType T, CallingConv CallConv);
+
   /// getComplexType - Return the uniqued reference to the type for a complex
   /// number with the specified element type.
   QualType getComplexType(QualType T);
@@ -513,7 +518,8 @@ public:
 
   /// getFunctionNoProtoType - Return a K&R style C function type like 'int()'.
   ///
-  QualType getFunctionNoProtoType(QualType ResultTy, bool NoReturn = false);
+  QualType getFunctionNoProtoType(QualType ResultTy, bool NoReturn = false,
+                                  CallingConv CallConv = CC_Default);
 
   /// getFunctionType - Return a normal function type with a typed argument
   /// list.  isVariadic indicates whether the argument list includes '...'.
@@ -522,7 +528,8 @@ public:
                            unsigned TypeQuals, bool hasExceptionSpec = false,
                            bool hasAnyExceptionSpec = false,
                            unsigned NumExs = 0, const QualType *ExArray = 0,
-                           bool NoReturn = false);
+                           bool NoReturn = false,
+                           CallingConv CallConv = CC_Default);
 
   /// getTypeDeclType - Return the unique reference to the type for
   /// the specified type declaration.
diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index 9b0cdc3a52..8e534d35cd 100644
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -385,6 +385,14 @@ public:
   }
 };
 
+/// CallingConv - Specifies the calling convention that a function uses.
+enum CallingConv {
+  CC_Default,
+  CC_C,           // __attribute__((cdecl))
+  CC_X86StdCall,  // __attribute__((stdcall))
+  CC_X86FastCall  // __attribute__((fastcall))
+};
+
 
 /// QualType - For efficiency, we don't store CV-qualified types as nodes on
 /// their own: instead each reference to a type stores the qualifiers.  This
@@ -669,6 +677,10 @@ public:
   /// false otherwise.
   bool getNoReturnAttr() const;
 
+  /// getCallConv - Returns the calling convention of the type if the type
+  /// is a function type, CC_Default otherwise.
+  CallingConv getCallConv() const;
+
 private:
   // These methods are implemented in a separate translation unit;
   // "static"-ize them to avoid creating temporary QualTypes in the
@@ -1691,21 +1703,25 @@ class FunctionType : public Type {
   /// NoReturn - Indicates if the function type is attribute noreturn.
   unsigned NoReturn : 1;
 
+  /// CallConv - The calling convention used by the function.
+  unsigned CallConv : 2;
+
   // The type returned by the function.
   QualType ResultType;
 protected:
   FunctionType(TypeClass tc, QualType res, bool SubclassInfo,
                unsigned typeQuals, QualType Canonical, bool Dependent,
-               bool noReturn = false)
+               bool noReturn = false, CallingConv callConv = CC_Default)
     : Type(tc, Canonical, Dependent),
       SubClassData(SubclassInfo), TypeQuals(typeQuals), NoReturn(noReturn),
-      ResultType(res) {}
+      CallConv(callConv), ResultType(res) {}
   bool getSubClassData() const { return SubClassData; }
   unsigned getTypeQuals() const { return TypeQuals; }
 public:
 
   QualType getResultType() const { return ResultType; }
   bool getNoReturnAttr() const { return NoReturn; }
+  CallingConv getCallConv() const { return (CallingConv)CallConv; }
 
   static bool classof(const Type *T) {
     return T->getTypeClass() == FunctionNoProto ||
@@ -1718,9 +1734,9 @@ public:
 /// no information available about its arguments.
 class FunctionNoProtoType : public FunctionType, public llvm::FoldingSetNode {
   FunctionNoProtoType(QualType Result, QualType Canonical,
-                      bool NoReturn = false)
+                      bool NoReturn = false, CallingConv CallConv = CC_Default)
     : FunctionType(FunctionNoProto, Result, false, 0, Canonical,
-                   /*Dependent=*/false, NoReturn) {}
+                   /*Dependent=*/false, NoReturn, CallConv) {}
   friend class ASTContext;  // ASTContext creates these.
 public:
   // No additional state past what FunctionType provides.
@@ -1762,10 +1778,12 @@ class FunctionProtoType : public FunctionType, public llvm::FoldingSetNode {
   FunctionProtoType(QualType Result, const QualType *ArgArray, unsigned numArgs,
                     bool isVariadic, unsigned typeQuals, bool hasExs,
                     bool hasAnyExs, const QualType *ExArray,
-                    unsigned numExs, QualType Canonical, bool NoReturn)
+                    unsigned numExs, QualType Canonical, bool NoReturn,
+                    CallingConv CallConv)
     : FunctionType(FunctionProto, Result, isVariadic, typeQuals, Canonical,
                    (Result->isDependentType() ||
-                    hasAnyDependentType(ArgArray, numArgs)), NoReturn),
+                    hasAnyDependentType(ArgArray, numArgs)), NoReturn,
+                   CallConv),
       NumArgs(numArgs), NumExceptions(numExs), HasExceptionSpec(hasExs),
       AnyExceptionSpec(hasAnyExs) {
     // Fill in the trailing argument array.
@@ -2797,6 +2815,26 @@ inline bool QualType::getNoReturnAttr() const {
   return false;
 }
 
+/// getCallConv - Returns the calling convention of the type if the type
+/// is a function type, CC_Default otherwise.
+inline CallingConv QualType::getCallConv() const {
+  if (const PointerType *PT = getTypePtr()->getAs<PointerType>())
+    return PT->getPointeeType().getCallConv();
+  else if (const ReferenceType *RT = getTypePtr()->getAs<ReferenceType>())
+    return RT->getPointeeType().getCallConv();
+  else if (const MemberPointerType *MPT =
+           getTypePtr()->getAs<MemberPointerType>())
+    return MPT->getPointeeType().getCallConv();
+  else if (const BlockPointerType *BPT =
+           getTypePtr()->getAs<BlockPointerType>()) {
+    if (const FunctionType *FT = BPT->getPointeeType()->getAs<FunctionType>())
+      return FT->getCallConv();
+  } else if (const FunctionType *FT = getTypePtr()->getAs<FunctionType>())
+    return FT->getCallConv();
+
+  return CC_Default;
+}
+
 /// isMoreQualifiedThan - Determine whether this type is more
 /// qualified than the Other type. For example, "const volatile int"
 /// is more qualified than "const int", "volatile int", and
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 76ec852cb8..c6e3e09fa5 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -1200,43 +1200,58 @@ QualType ASTContext::getObjCGCQualType(QualType T,
   return getExtQualType(TypeNode, Quals);
 }
 
-QualType ASTContext::getNoReturnType(QualType T, bool AddNoReturn) {
+static QualType getNoReturnCallConvType(ASTContext& Context, QualType T,
+                                        bool AddNoReturn,
+                                        CallingConv CallConv) {
   QualType ResultType;
   if (const PointerType *Pointer = T->getAs<PointerType>()) {
     QualType Pointee = Pointer->getPointeeType();
-    ResultType = getNoReturnType(Pointee, AddNoReturn);
+    ResultType = getNoReturnCallConvType(Context, Pointee, AddNoReturn,
+                                         CallConv);
     if (ResultType == Pointee)
       return T;
-    
-    ResultType = getPointerType(ResultType);
+
+    ResultType = Context.getPointerType(ResultType);
   } else if (const BlockPointerType *BlockPointer
                                               = T->getAs<BlockPointerType>()) {
     QualType Pointee = BlockPointer->getPointeeType();
-    ResultType = getNoReturnType(Pointee, AddNoReturn);
+    ResultType = getNoReturnCallConvType(Context, Pointee, AddNoReturn,
+                                         CallConv);
     if (ResultType == Pointee)
       return T;
-    
-    ResultType = getBlockPointerType(ResultType);
-  } else if (const FunctionType *F = T->getAs<FunctionType>()) {
-    if (F->getNoReturnAttr() == AddNoReturn)
+
+    ResultType = Context.getBlockPointerType(ResultType);
+   } else if (const FunctionType *F = T->getAs<FunctionType>()) {
+    if (F->getNoReturnAttr() == AddNoReturn && F->getCallConv() == CallConv)
       return T;
-    
+
     if (const FunctionNoProtoType *FNPT = dyn_cast<FunctionNoProtoType>(F)) {
-      ResultType = getFunctionNoProtoType(FNPT->getResultType(), AddNoReturn);
+      ResultType = Context.getFunctionNoProtoType(FNPT->getResultType(),
+                                                  AddNoReturn, CallConv);
     } else {
       const FunctionProtoType *FPT = cast<FunctionProtoType>(F);
       ResultType
-        = getFunctionType(FPT->getResultType(), FPT->arg_type_begin(),
-                          FPT->getNumArgs(), FPT->isVariadic(), 
-                          FPT->getTypeQuals(),
-                          FPT->hasExceptionSpec(), FPT->hasAnyExceptionSpec(),
-                          FPT->getNumExceptions(), FPT->exception_begin(), 
-                          AddNoReturn);
+        = Context.getFunctionType(FPT->getResultType(), FPT->arg_type_begin(),
+                                  FPT->getNumArgs(), FPT->isVariadic(),
+                                  FPT->getTypeQuals(),
+                                  FPT->hasExceptionSpec(),
+                                  FPT->hasAnyExceptionSpec(),
+                                  FPT->getNumExceptions(),
+                                  FPT->exception_begin(),
+                                  AddNoReturn, CallConv);
     }
   } else
     return T;
-  
-  return getQualifiedType(ResultType, T.getLocalQualifiers());
+
+  return Context.getQualifiedType(ResultType, T.getLocalQualifiers());
+}
+
+QualType ASTContext::getNoReturnType(QualType T, bool AddNoReturn) {
+  return getNoReturnCallConvType(*this, T, AddNoReturn, T.getCallConv());
+}
+
+QualType ASTContext::getCallConvType(QualType T, CallingConv CallConv) {
+  return getNoReturnCallConvType(*this, T, T.getNoReturnAttr(), CallConv);
 }
 
 /// getComplexType - Return the uniqued reference to the type for a complex
@@ -1679,9 +1694,16 @@ QualType ASTContext::getDependentSizedExtVectorType(QualType vecType,
   return QualType(New, 0);
 }
 
+static CallingConv getCanonicalCallingConv(CallingConv CC) {
+  if (CC == CC_C)
+    return CC_Default;
+  return CC;
+}
+
 /// getFunctionNoProtoType - Return a K&R style C function type like 'int()'.
 ///
-QualType ASTContext::getFunctionNoProtoType(QualType ResultTy, bool NoReturn) {
+QualType ASTContext::getFunctionNoProtoType(QualType ResultTy, bool NoReturn,
+                                            CallingConv CallConv) {
   // Unique functions, to guarantee there is only one function of a particular
   // structure.
   llvm::FoldingSetNodeID ID;
@@ -1693,8 +1715,10 @@ QualType ASTContext::getFunctionNoProtoType(QualType ResultTy, bool NoReturn) {
     return QualType(FT, 0);
 
   QualType Canonical;
-  if (!ResultTy.isCanonical()) {
-    Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy), NoReturn);
+  if (!ResultTy.isCanonical() ||
+      getCanonicalCallingConv(CallConv) != CallConv) {
+    Canonical = getFunctionNoProtoType(getCanonicalType(ResultTy), NoReturn,
+                                       getCanonicalCallingConv(CallConv));
 
     // Get the new insert position for the node we care about.
     FunctionNoProtoType *NewIP =
@@ -1715,7 +1739,8 @@ QualType ASTContext::getFunctionType(QualType ResultTy,const QualType *ArgArray,
                                      unsigned NumArgs, bool isVariadic,
                                      unsigned TypeQuals, bool hasExceptionSpec,
                                      bool hasAnyExceptionSpec, unsigned NumExs,
-                                     const QualType *ExArray, bool NoReturn) {
+                                     const QualType *ExArray, bool NoReturn,
+                                     CallingConv CallConv) {
   // Unique functions, to guarantee there is only one function of a particular
   // structure.
   llvm::FoldingSetNodeID ID;
@@ -1737,7 +1762,7 @@ QualType ASTContext::getFunctionType(QualType ResultTy,const QualType *ArgArray,
   // If this type isn't canonical, get the canonical version of it.
   // The exception spec is not part of the canonical type.
   QualType Canonical;
-  if (!isCanonical) {
+  if (!isCanonical || getCanonicalCallingConv(CallConv) != CallConv) {
     llvm::SmallVector<QualType, 16> CanonicalArgs;
     CanonicalArgs.reserve(NumArgs);
     for (unsigned i = 0; i != NumArgs; ++i)
@@ -1746,7 +1771,8 @@ QualType ASTContext::getFunctionType(QualType ResultTy,const QualType *ArgArray,
     Canonical = getFunctionType(getCanonicalType(ResultTy),
                                 CanonicalArgs.data(), NumArgs,
                                 isVariadic, TypeQuals, false,
-                                false, 0, 0, NoReturn);
+                                false, 0, 0, NoReturn,
+                                getCanonicalCallingConv(CallConv));
 
     // Get the new insert position for the node we care about.
     FunctionProtoType *NewIP =
@@ -1763,7 +1789,7 @@ QualType ASTContext::getFunctionType(QualType ResultTy,const QualType *ArgArray,
                                  NumExs*sizeof(QualType), TypeAlignment);
   new (FTP) FunctionProtoType(ResultTy, ArgArray, NumArgs, isVariadic,
                               TypeQuals, hasExceptionSpec, hasAnyExceptionSpec,
-                              ExArray, NumExs, Canonical, NoReturn);
+                              ExArray, NumExs, Canonical, NoReturn, CallConv);
   Types.push_back(FTP);
   FunctionProtoTypes.InsertNode(FTP, InsertPos);
   return QualType(FTP, 0);
@@ -4211,6 +4237,10 @@ bool ASTContext::typesAreCompatible(QualType LHS, QualType RHS) {
   return !mergeTypes(LHS, RHS).isNull();
 }
 
+static bool isSameCallingConvention(CallingConv lcc, CallingConv rcc) {
+  return (getCanonicalCallingConv(lcc) == getCanonicalCallingConv(rcc));
+}
+
 QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs) {
   const FunctionType *lbase = lhs->getAs<FunctionType>();
   const FunctionType *rbase = rhs->getAs<FunctionType>();
@@ -4232,6 +4262,11 @@ QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs) {
     allLTypes = false;
   if (NoReturn != rbase->getNoReturnAttr())
     allRTypes = false;
+  CallingConv lcc = lbase->getCallConv();
+  CallingConv rcc = rbase->getCallConv();
+  // Compatible functions must have compatible calling conventions
+  if (!isSameCallingConvention(lcc, rcc))
+    return QualType();
 
   if (lproto && rproto) { // two C99 style function prototypes
     assert(!lproto->hasExceptionSpec() && !rproto->hasExceptionSpec() &&
@@ -4267,7 +4302,7 @@ QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs) {
     if (allRTypes) return rhs;
     return getFunctionType(retType, types.begin(), types.size(),
                            lproto->isVariadic(), lproto->getTypeQuals(),
-                           NoReturn);
+                           NoReturn, lcc);
   }
 
   if (lproto) allRTypes = false;
@@ -4294,12 +4329,12 @@ QualType ASTContext::mergeFunctionTypes(QualType lhs, QualType rhs) {
     if (allRTypes) return rhs;
     return getFunctionType(retType, proto->arg_type_begin(),
                            proto->getNumArgs(), proto->isVariadic(),
-                           proto->getTypeQuals(), NoReturn);
+                           proto->getTypeQuals(), NoReturn, lcc);
   }
 
   if (allLTypes) return lhs;
   if (allRTypes) return rhs;
-  return getFunctionNoProtoType(retType, NoReturn);
+  return getFunctionNoProtoType(retType, NoReturn, lcc);
 }
 
 QualType ASTContext::mergeTypes(QualType LHS, QualType RHS) {
diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index 07d5a78bea..1f23bd2141 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -1909,18 +1909,20 @@ QualType PCHReader::ReadTypeRecord(uint64_t Offset) {
   }
 
   case pch::TYPE_FUNCTION_NO_PROTO: {
-    if (Record.size() != 2) {
+    if (Record.size() != 3) {
       Error("incorrect encoding of no-proto function type");
       return QualType();
     }
     QualType ResultType = GetType(Record[0]);
-    return Context->getFunctionNoProtoType(ResultType, Record[1]);
+    return Context->getFunctionNoProtoType(ResultType, Record[1],
+                                           (CallingConv)Record[2]);
   }
 
   case pch::TYPE_FUNCTION_PROTO: {
     QualType ResultType = GetType(Record[0]);
     bool NoReturn = Record[1];
-    unsigned Idx = 2;
+    CallingConv CallConv = (CallingConv)Record[2];
+    unsigned Idx = 3;
     unsigned NumParams = Record[Idx++];
     llvm::SmallVector<QualType, 16> ParamTypes;
     for (unsigned I = 0; I != NumParams; ++I)
@@ -1936,7 +1938,7 @@ QualType PCHReader::ReadTypeRecord(uint64_t Offset) {
     return Context->getFunctionType(ResultType, ParamTypes.data(), NumParams,
                                     isVariadic, Quals, hasExceptionSpec,
                                     hasAnyExceptionSpec, NumExceptions,
-                                    Exceptions.data(), NoReturn);
+                                    Exceptions.data(), NoReturn, CallConv);
   }
 
   case pch::TYPE_UNRESOLVED_USING:
diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index 3f6841b545..21e09744e3 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -139,6 +139,8 @@ void PCHTypeWriter::VisitExtVectorType(const ExtVectorType *T) {
 void PCHTypeWriter::VisitFunctionType(const FunctionType *T) {
   Writer.AddTypeRef(T->getResultType(), Record);
   Record.push_back(T->getNoReturnAttr());
+  // FIXME: need to stabilize encoding of calling convention...
+  Record.push_back(T->getCallConv());
 }
 
 void PCHTypeWriter::VisitFunctionNoProtoType(const FunctionNoProtoType *T) {
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 98619f3a16..e3a180a578 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1548,7 +1548,8 @@ TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
                                                  Proto->hasAnyExceptionSpec(),
                                                  Exceptions.size(),
                                                  Exceptions.data(),
-                                                 Proto->getNoReturnAttr()));
+                                                 Proto->getNoReturnAttr(),
+                                                 Proto->getCallConv()));
   }
 
   return false;