Convert clang::LangAS to a strongly typed enum

Summary:
Convert clang::LangAS to a strongly typed enum

Currently both clang AST address spaces and target specific address spaces
are represented as unsigned which can lead to subtle errors if the wrong
type is passed. It is especially confusing in the CodeGen files as it is
not possible to see what kind of address space should be passed to a
function without looking at the implementation.
I originally made this change for our LLVM fork for the CHERI architecture
where we make extensive use of address spaces to differentiate between
capabilities and pointers. When merging the upstream changes I usually
run into some test failures or runtime crashes because the wrong kind of
address space is passed to a function. By converting the LangAS enum to a
C++11 we can catch these errors at compile time. Additionally, it is now
obvious from the function signature which kind of address space it expects.

I found the following errors while writing this patch:

- ItaniumRecordLayoutBuilder::LayoutField was passing a clang AST address
  space to  TargetInfo::getPointer{Width,Align}()
- TypePrinter::printAttributedAfter() prints the numeric value of the
  clang AST address space instead of the target address space.
  However, this code is not used so I kept the current behaviour
- initializeForBlockHeader() in CGBlocks.cpp was passing
  LangAS::opencl_generic to TargetInfo::getPointer{Width,Align}()
- CodeGenFunction::EmitBlockLiteral() was passing a AST address space to
  TargetInfo::getPointerWidth()
- CGOpenMPRuntimeNVPTX::translateParameter() passed a target address space
  to Qualifiers::addAddressSpace()
- CGOpenMPRuntimeNVPTX::getParameterAddress() was using
  llvm::Type::getPointerTo() with a AST address space
- clang_getAddressSpace() returns either a LangAS or a target address
  space. As this is exposed to C I have kept the current behaviour and
  added a comment stating that it is probably not correct.

Other than this the patch should not cause any functional changes.

Reviewers: yaxunl, pcc, bader

Reviewed By: yaxunl, bader

Subscribers: jlebar, jholewinski, nhaehnle, Anastasia, cfe-commits

Differential Revision: https://reviews.llvm.org/D38816

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@315871 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/AST/ASTContext.h

@@ -496,7 +496,7 @@ private:
   CXXABI *createCXXABI(const TargetInfo &T);
 
   /// \brief The logical -> physical address space map.
-  const LangAS::Map *AddrSpaceMap;
+  const LangASMap *AddrSpaceMap;
 
   /// \brief Address space map mangling must be used with language specific
   /// address spaces (e.g. OpenCL/CUDA)
@@ -1070,7 +1070,7 @@ public:
   /// The resulting type has a union of the qualifiers from T and the address
   /// space. If T already has an address space specifier, it is silently
   /// replaced.
-  QualType getAddrSpaceQualType(QualType T, unsigned AddressSpace) const;
+  QualType getAddrSpaceQualType(QualType T, LangAS AddressSpace) const;
 
   /// \brief Remove any existing address space on the type and returns the type
   /// with qualifiers intact (or that's the idea anyway)
@@ -2363,14 +2363,14 @@ public:
     return getTargetAddressSpace(Q.getAddressSpace());
   }
 
-  unsigned getTargetAddressSpace(unsigned AS) const;
+  unsigned getTargetAddressSpace(LangAS AS) const;
 
   /// Get target-dependent integer value for null pointer which is used for
   /// constant folding.
   uint64_t getTargetNullPointerValue(QualType QT) const;
 
-  bool addressSpaceMapManglingFor(unsigned AS) const {
-    return AddrSpaceMapMangling || AS >= LangAS::FirstTargetAddressSpace;
+  bool addressSpaceMapManglingFor(LangAS AS) const {
+    return AddrSpaceMapMangling || isTargetAddressSpace(AS);
   }
 
 private:

include/clang/AST/Type.h

@@ -328,9 +328,11 @@ public:
   }
 
   bool hasAddressSpace() const { return Mask & AddressSpaceMask; }
-  unsigned getAddressSpace() const { return Mask >> AddressSpaceShift; }
+  LangAS getAddressSpace() const {
+    return static_cast<LangAS>(Mask >> AddressSpaceShift);
+  }
   bool hasTargetSpecificAddressSpace() const {
-    return getAddressSpace() >= LangAS::FirstTargetAddressSpace;
+    return isTargetAddressSpace(getAddressSpace());
   }
   /// Get the address space attribute value to be printed by diagnostics.
   unsigned getAddressSpaceAttributePrintValue() const {
@@ -338,22 +340,22 @@ public:
     // This function is not supposed to be used with language specific
     // address spaces. If that happens, the diagnostic message should consider
     // printing the QualType instead of the address space value.
-    assert(Addr == 0 || hasTargetSpecificAddressSpace());
-    if (Addr)
-      return Addr - LangAS::FirstTargetAddressSpace;
+    assert(Addr == LangAS::Default || hasTargetSpecificAddressSpace());
+    if (Addr != LangAS::Default)
+      return toTargetAddressSpace(Addr);
     // TODO: The diagnostic messages where Addr may be 0 should be fixed
     // since it cannot differentiate the situation where 0 denotes the default
     // address space or user specified __attribute__((address_space(0))).
     return 0;
   }
-  void setAddressSpace(unsigned space) {
-    assert(space <= MaxAddressSpace);
+  void setAddressSpace(LangAS space) {
+    assert((unsigned)space <= MaxAddressSpace);
     Mask = (Mask & ~AddressSpaceMask)
          | (((uint32_t) space) << AddressSpaceShift);
   }
-  void removeAddressSpace() { setAddressSpace(0); }
-  void addAddressSpace(unsigned space) {
-    assert(space);
+  void removeAddressSpace() { setAddressSpace(LangAS::Default); }
+  void addAddressSpace(LangAS space) {
+    assert(space != LangAS::Default);
     setAddressSpace(space);
   }
 
@@ -1005,7 +1007,7 @@ public:
   }
 
   /// Return the address space of this type.
-  inline unsigned getAddressSpace() const;
+  inline LangAS getAddressSpace() const;
 
   /// Returns gc attribute of this type.
   inline Qualifiers::GC getObjCGCAttr() const;
@@ -1230,7 +1232,7 @@ public:
   }
 
   bool hasAddressSpace() const { return Quals.hasAddressSpace(); }
-  unsigned getAddressSpace() const { return Quals.getAddressSpace(); }
+  LangAS getAddressSpace() const { return Quals.getAddressSpace(); }
 
   const Type *getBaseType() const { return BaseType; }
 
@@ -5654,7 +5656,7 @@ inline void QualType::removeLocalCVRQualifiers(unsigned Mask) {
 }
 
 /// Return the address space of this type.
-inline unsigned QualType::getAddressSpace() const {
+inline LangAS QualType::getAddressSpace() const {
   return getQualifiers().getAddressSpace();
 }
 

include/clang/Basic/AddressSpaces.h

@@ -16,14 +16,14 @@
 #ifndef LLVM_CLANG_BASIC_ADDRESSSPACES_H
 #define LLVM_CLANG_BASIC_ADDRESSSPACES_H
 
-namespace clang {
+#include <assert.h>
 
-namespace LangAS {
+namespace clang {
 
 /// \brief Defines the address space values used by the address space qualifier
 /// of QualType.
 ///
-enum ID {
+enum class LangAS : unsigned {
   // The default value 0 is the value used in QualType for the the situation
   // where there is no address space qualifier.
   Default = 0,
@@ -51,9 +51,24 @@ enum ID {
 
 /// The type of a lookup table which maps from language-specific address spaces
 /// to target-specific ones.
-typedef unsigned Map[FirstTargetAddressSpace];
+typedef unsigned LangASMap[(unsigned)LangAS::FirstTargetAddressSpace];
+
+/// \return whether \p AS is a target-specific address space rather than a
+/// clang AST address space
+inline bool isTargetAddressSpace(LangAS AS) {
+  return (unsigned)AS >= (unsigned)LangAS::FirstTargetAddressSpace;
 }
 
+inline unsigned toTargetAddressSpace(LangAS AS) {
+  assert(isTargetAddressSpace(AS));
+  return (unsigned)AS - (unsigned)LangAS::FirstTargetAddressSpace;
 }
 
+inline LangAS getLangASFromTargetAS(unsigned TargetAS) {
+  return static_cast<LangAS>((TargetAS) +
+                             (unsigned)LangAS::FirstTargetAddressSpace);
+}
+
+} // namespace clang
+
 #endif

include/clang/Basic/TargetInfo.h

@@ -86,7 +86,7 @@ protected:
     *LongDoubleFormat, *Float128Format;
   unsigned char RegParmMax, SSERegParmMax;
   TargetCXXABI TheCXXABI;
-  const LangAS::Map *AddrSpaceMap;
+  const LangASMap *AddrSpaceMap;
 
   mutable StringRef PlatformName;
   mutable VersionTuple PlatformMinVersion;
@@ -322,9 +322,7 @@ public:
 
   /// \brief Get integer value for null pointer.
   /// \param AddrSpace address space of pointee in source language.
-  virtual uint64_t getNullPointerValue(unsigned AddrSpace) const {
-    return 0;
-  }
+  virtual uint64_t getNullPointerValue(LangAS AddrSpace) const { return 0; }
 
   /// \brief Return the size of '_Bool' and C++ 'bool' for this target, in bits.
   unsigned getBoolWidth() const { return BoolWidth; }
@@ -971,15 +969,13 @@ public:
     return nullptr;
   }
 
-  const LangAS::Map &getAddressSpaceMap() const {
-    return *AddrSpaceMap;
-  }
+  const LangASMap &getAddressSpaceMap() const { return *AddrSpaceMap; }
 
   /// \brief Return an AST address space which can be used opportunistically
   /// for constant global memory. It must be possible to convert pointers into
   /// this address space to LangAS::Default. If no such address space exists,
   /// this may return None, and such optimizations will be disabled.
-  virtual llvm::Optional<unsigned> getConstantAddressSpace() const {
+  virtual llvm::Optional<LangAS> getConstantAddressSpace() const {
     return LangAS::Default;
   }
 
@@ -1058,7 +1054,7 @@ public:
   }
 
   /// \brief Get address space for OpenCL type.
-  virtual LangAS::ID getOpenCLTypeAddrSpace(const Type *T) const;
+  virtual LangAS getOpenCLTypeAddrSpace(const Type *T) const;
 
   /// \returns Target specific vtbl ptr address space.
   virtual unsigned getVtblPtrAddressSpace() const {

lib/AST/ASTContext.cpp

@@ -697,8 +697,8 @@ CXXABI *ASTContext::createCXXABI(const TargetInfo &T) {
   llvm_unreachable("Invalid CXXABI type!");
 }
 
-static const LangAS::Map *getAddressSpaceMap(const TargetInfo &T,
-                                             const LangOptions &LOpts) {
+static const LangASMap *getAddressSpaceMap(const TargetInfo &T,
+                                           const LangOptions &LOpts) {
   if (LOpts.FakeAddressSpaceMap) {
     // The fake address space map must have a distinct entry for each
     // language-specific address space.
@@ -2283,8 +2283,8 @@ ASTContext::getExtQualType(const Type *baseType, Qualifiers quals) const {
   return QualType(eq, fastQuals);
 }
 
-QualType
-ASTContext::getAddrSpaceQualType(QualType T, unsigned AddressSpace) const {
+QualType ASTContext::getAddrSpaceQualType(QualType T,
+                                          LangAS AddressSpace) const {
   QualType CanT = getCanonicalType(T);
   if (CanT.getAddressSpace() == AddressSpace)
     return T;
@@ -8870,8 +8870,8 @@ static QualType DecodeTypeFromStr(const char *&Str, const ASTContext &Context,
       char *End;
       unsigned AddrSpace = strtoul(Str, &End, 10);
       if (End != Str && AddrSpace != 0) {
-        Type = Context.getAddrSpaceQualType(
-            Type, AddrSpace + LangAS::FirstTargetAddressSpace);
+        Type = Context.getAddrSpaceQualType(Type,
+                                            getLangASFromTargetAS(AddrSpace));
         Str = End;
       }
       if (c == '*')
@@ -9694,20 +9694,20 @@ ASTContext::ObjCMethodsAreEqual(const ObjCMethodDecl *MethodDecl,
 }
 
 uint64_t ASTContext::getTargetNullPointerValue(QualType QT) const {
-  unsigned AS;
+  LangAS AS;
   if (QT->getUnqualifiedDesugaredType()->isNullPtrType())
-    AS = 0;
+    AS = LangAS::Default;
   else
     AS = QT->getPointeeType().getAddressSpace();
 
   return getTargetInfo().getNullPointerValue(AS);
 }
 
-unsigned ASTContext::getTargetAddressSpace(unsigned AS) const {
-  if (AS >= LangAS::FirstTargetAddressSpace)
-    return AS - LangAS::FirstTargetAddressSpace;
+unsigned ASTContext::getTargetAddressSpace(LangAS AS) const {
+  if (isTargetAddressSpace(AS))
+    return toTargetAddressSpace(AS);
   else
-    return (*AddrSpaceMap)[AS];
+    return (*AddrSpaceMap)[(unsigned)AS];
 }
 
 // Explicitly instantiate this in case a Redeclarable<T> is used from a TU that

lib/AST/ItaniumMangle.cpp

@@ -2222,7 +2222,7 @@ void CXXNameMangler::mangleQualifiers(Qualifiers Quals, const DependentAddressSp
     //   <type> ::= U <CUDA-addrspace>
 
     SmallString<64> ASString;
-    unsigned AS = Quals.getAddressSpace();
+    LangAS AS = Quals.getAddressSpace();
 
     if (Context.getASTContext().addressSpaceMapManglingFor(AS)) {
       //  <target-addrspace> ::= "AS" <address-space-number>

lib/AST/RecordLayoutBuilder.cpp

@@ -1731,7 +1731,7 @@ void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
     const ArrayType* ATy = Context.getAsArrayType(D->getType());
     FieldAlign = Context.getTypeAlignInChars(ATy->getElementType());
   } else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
-    unsigned AS = RT->getPointeeType().getAddressSpace();
+    unsigned AS = Context.getTargetAddressSpace(RT->getPointeeType());
     FieldSize = 
       Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(AS));
     FieldAlign = 

lib/AST/TypePrinter.cpp

@@ -1320,7 +1320,9 @@ void TypePrinter::printAttributedAfter(const AttributedType *T,
   default: llvm_unreachable("This attribute should have been handled already");
   case AttributedType::attr_address_space:
     OS << "address_space(";
-    OS << T->getEquivalentType().getAddressSpace();
+    // FIXME: printing the raw LangAS value is wrong. This should probably
+    // use the same code as Qualifiers::print()
+    OS << (unsigned)T->getEquivalentType().getAddressSpace();
     OS << ')';
     break;
 
@@ -1645,7 +1647,7 @@ bool Qualifiers::isEmptyWhenPrinted(const PrintingPolicy &Policy) const {
   if (getCVRQualifiers())
     return false;
 
-  if (getAddressSpace())
+  if (getAddressSpace() != LangAS::Default)
     return false;
 
   if (getObjCGCAttr())
@@ -1676,7 +1678,8 @@ void Qualifiers::print(raw_ostream &OS, const PrintingPolicy& Policy,
     OS << "__unaligned";
     addSpace = true;
   }
-  if (unsigned addrspace = getAddressSpace()) {
+  LangAS addrspace = getAddressSpace();
+  if (addrspace != LangAS::Default) {
     if (addrspace != LangAS::opencl_private) {
       if (addSpace)
         OS << ' ';
@@ -1704,9 +1707,8 @@ void Qualifiers::print(raw_ostream &OS, const PrintingPolicy& Policy,
         OS << "__shared";
         break;
       default:
-        assert(addrspace >= LangAS::FirstTargetAddressSpace);
         OS << "__attribute__((address_space(";
-        OS << addrspace - LangAS::FirstTargetAddressSpace;
+        OS << toTargetAddressSpace(addrspace);
         OS << ")))";
       }
     }

lib/Basic/TargetInfo.cpp

@@ -23,7 +23,7 @@
 #include <cstdlib>
 using namespace clang;
 
-static const LangAS::Map DefaultAddrSpaceMap = { 0 };
+static const LangASMap DefaultAddrSpaceMap = {0};
 
 // TargetInfo Constructor.
 TargetInfo::TargetInfo(const llvm::Triple &T) : TargetOpts(), Triple(T) {
@@ -356,7 +356,7 @@ bool TargetInfo::initFeatureMap(
   return true;
 }
 
-LangAS::ID TargetInfo::getOpenCLTypeAddrSpace(const Type *T) const {
+LangAS TargetInfo::getOpenCLTypeAddrSpace(const Type *T) const {
   auto BT = dyn_cast<BuiltinType>(T);
 
   if (!BT) {

lib/Basic/Targets/AMDGPU.cpp

@@ -42,7 +42,7 @@ static const char *const DataLayoutStringSIGenericIsZero =
     "-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128"
     "-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-A5";
 
-static const LangAS::Map AMDGPUPrivIsZeroDefIsGenMap = {
+static const LangASMap AMDGPUPrivIsZeroDefIsGenMap = {
     4, // Default
     1, // opencl_global
     3, // opencl_local
@@ -54,7 +54,7 @@ static const LangAS::Map AMDGPUPrivIsZeroDefIsGenMap = {
     3  // cuda_shared
 };
 
-static const LangAS::Map AMDGPUGenIsZeroDefIsGenMap = {
+static const LangASMap AMDGPUGenIsZeroDefIsGenMap = {
     0, // Default
     1, // opencl_global
     3, // opencl_local
@@ -66,7 +66,7 @@ static const LangAS::Map AMDGPUGenIsZeroDefIsGenMap = {
     3  // cuda_shared
 };
 
-static const LangAS::Map AMDGPUPrivIsZeroDefIsPrivMap = {
+static const LangASMap AMDGPUPrivIsZeroDefIsPrivMap = {
     0, // Default
     1, // opencl_global
     3, // opencl_local
@@ -78,7 +78,7 @@ static const LangAS::Map AMDGPUPrivIsZeroDefIsPrivMap = {
     3  // cuda_shared
 };
 
-static const LangAS::Map AMDGPUGenIsZeroDefIsPrivMap = {
+static const LangASMap AMDGPUGenIsZeroDefIsPrivMap = {
     5, // Default
     1, // opencl_global
     3, // opencl_local

lib/Basic/Targets/AMDGPU.h

@@ -258,7 +258,7 @@ public:
     }
   }
 
-  LangAS::ID getOpenCLTypeAddrSpace(const Type *T) const override {
+  LangAS getOpenCLTypeAddrSpace(const Type *T) const override {
     auto BT = dyn_cast<BuiltinType>(T);
 
     if (!BT)
@@ -279,8 +279,8 @@ public:
     }
   }
 
-  llvm::Optional<unsigned> getConstantAddressSpace() const override {
-    return LangAS::FirstTargetAddressSpace + AS.Constant;
+  llvm::Optional<LangAS> getConstantAddressSpace() const override {
+    return getLangASFromTargetAS(AS.Constant);
   }
 
   /// \returns Target specific vtbl ptr address space.
@@ -318,7 +318,7 @@ public:
   // In amdgcn target the null pointer in global, constant, and generic
   // address space has value 0 but in private and local address space has
   // value ~0.
-  uint64_t getNullPointerValue(unsigned AS) const override {
+  uint64_t getNullPointerValue(LangAS AS) const override {
     return AS == LangAS::opencl_local ? ~0 : 0;
   }
 };

lib/CodeGen/CGBlocks.cpp

@@ -309,10 +309,12 @@ static void initializeForBlockHeader(CodeGenModule &CGM, CGBlockInfo &info,
   if (CGM.getLangOpts().OpenCL) {
     // The header is basically 'struct { int; int; generic void *;
     // custom_fields; }'. Assert that struct is packed.
-    auto GenPtrAlign = CharUnits::fromQuantity(
-        CGM.getTarget().getPointerAlign(LangAS::opencl_generic) / 8);
-    auto GenPtrSize = CharUnits::fromQuantity(
-        CGM.getTarget().getPointerWidth(LangAS::opencl_generic) / 8);
+    auto GenericAS =
+        CGM.getContext().getTargetAddressSpace(LangAS::opencl_generic);
+    auto GenPtrAlign =
+        CharUnits::fromQuantity(CGM.getTarget().getPointerAlign(GenericAS) / 8);
+    auto GenPtrSize =
+        CharUnits::fromQuantity(CGM.getTarget().getPointerWidth(GenericAS) / 8);
     assert(CGM.getIntSize() <= GenPtrSize);
     assert(CGM.getIntAlign() <= GenPtrAlign);
     assert((2 * CGM.getIntSize()).isMultipleOf(GenPtrAlign));
@@ -775,9 +777,11 @@ llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo,
   bool IsOpenCL = CGM.getContext().getLangOpts().OpenCL;
   auto GenVoidPtrTy =
       IsOpenCL ? CGM.getOpenCLRuntime().getGenericVoidPointerType() : VoidPtrTy;
-  unsigned GenVoidPtrAddr = IsOpenCL ? LangAS::opencl_generic : LangAS::Default;
+  LangAS GenVoidPtrAddr = IsOpenCL ? LangAS::opencl_generic : LangAS::Default;
   auto GenVoidPtrSize = CharUnits::fromQuantity(
-      CGM.getTarget().getPointerWidth(GenVoidPtrAddr) / 8);
+      CGM.getTarget().getPointerWidth(
+          CGM.getContext().getTargetAddressSpace(GenVoidPtrAddr)) /
+      8);
   // Using the computed layout, generate the actual block function.
   bool isLambdaConv = blockInfo.getBlockDecl()->isConversionFromLambda();
   auto *InvokeFn = CodeGenFunction(CGM, true).GenerateBlockFunction(

lib/CodeGen/CGDecl.cpp

@@ -222,7 +222,7 @@ llvm::Constant *CodeGenModule::getOrCreateStaticVarDecl(
     Name = getStaticDeclName(*this, D);
 
   llvm::Type *LTy = getTypes().ConvertTypeForMem(Ty);
-  unsigned AS = GetGlobalVarAddressSpace(&D);
+  LangAS AS = GetGlobalVarAddressSpace(&D);
   unsigned TargetAS = getContext().getTargetAddressSpace(AS);
 
   // Local address space cannot have an initializer.
@@ -252,7 +252,7 @@ llvm::Constant *CodeGenModule::getOrCreateStaticVarDecl(
   }
 
   // Make sure the result is of the correct type.
-  unsigned ExpectedAS = Ty.getAddressSpace();
+  LangAS ExpectedAS = Ty.getAddressSpace();
   llvm::Constant *Addr = GV;
   if (AS != ExpectedAS) {
     Addr = getTargetCodeGenInfo().performAddrSpaceCast(

lib/CodeGen/CGExprConstant.cpp

@@ -612,7 +612,7 @@ static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM,
           CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
     return ConstantAddress(Addr, Align);
 
-  unsigned addressSpace = E->getType().getAddressSpace();
+  LangAS addressSpace = E->getType().getAddressSpace();
 
   ConstantEmitter emitter(CGM, CGF);
   llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
@@ -725,8 +725,8 @@ public:
     case CK_AddressSpaceConversion: {
       auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
       if (!C) return nullptr;
-      unsigned destAS = E->getType()->getPointeeType().getAddressSpace();
-      unsigned srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
+      LangAS destAS = E->getType()->getPointeeType().getAddressSpace();
+      LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
       llvm::Type *destTy = ConvertType(E->getType());
       return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS,
                                                              destAS, destTy);
@@ -1184,14 +1184,14 @@ llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
 }
 
 llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
-                                                       unsigned destAddrSpace,
+                                                       LangAS destAddrSpace,
                                                        QualType destType) {
   initializeNonAbstract(destAddrSpace);
   return markIfFailed(tryEmitPrivateForMemory(E, destType));
 }
 
 llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value,
-                                                    unsigned destAddrSpace,
+                                                    LangAS destAddrSpace,
                                                     QualType destType) {
   initializeNonAbstract(destAddrSpace);
   auto C = tryEmitPrivateForMemory(value, destType);

lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp

@@ -2253,7 +2253,7 @@ CGOpenMPRuntimeNVPTX::translateParameter(const FieldDecl *FD,
   ArgType = CGM.getContext().getPointerType(PointeeTy);
   QC.addRestrict();
   enum { NVPTX_local_addr = 5 };
-  QC.addAddressSpace(NVPTX_local_addr);
+  QC.addAddressSpace(getLangASFromTargetAS(NVPTX_local_addr));
   ArgType = QC.apply(CGM.getContext(), ArgType);
   return ImplicitParamDecl::Create(
       CGM.getContext(), /*DC=*/nullptr, NativeParam->getLocation(),
@@ -2273,7 +2273,7 @@ CGOpenMPRuntimeNVPTX::getParameterAddress(CodeGenFunction &CGF,
   const Type *NonQualTy = QC.strip(NativeParamType);
   QualType NativePointeeTy = cast<ReferenceType>(NonQualTy)->getPointeeType();
   unsigned NativePointeeAddrSpace =
-      NativePointeeTy.getQualifiers().getAddressSpace();
+      CGF.getContext().getTargetAddressSpace(NativePointeeTy);
   QualType TargetTy = TargetParam->getType();
   llvm::Value *TargetAddr = CGF.EmitLoadOfScalar(
       LocalAddr, /*Volatile=*/false, TargetTy, SourceLocation());

lib/CodeGen/CGValue.h

@@ -314,7 +314,7 @@ public:
   const Qualifiers &getQuals() const { return Quals; }
   Qualifiers &getQuals() { return Quals; }
 
-  unsigned getAddressSpace() const { return Quals.getAddressSpace(); }
+  LangAS getAddressSpace() const { return Quals.getAddressSpace(); }
 
   CharUnits getAlignment() const { return CharUnits::fromQuantity(Alignment); }
   void setAlignment(CharUnits A) { Alignment = A.getQuantity(); }

lib/CodeGen/CodeGenFunction.cpp

@@ -525,8 +525,8 @@ static void removeImageAccessQualifier(std::string& TyName) {
 // for example in clGetKernelArgInfo() implementation between the address
 // spaces with targets without unique mapping to the OpenCL address spaces
 // (basically all single AS CPUs).
-static unsigned ArgInfoAddressSpace(unsigned LangAS) {
-  switch (LangAS) {
+static unsigned ArgInfoAddressSpace(LangAS AS) {
+  switch (AS) {
   case LangAS::opencl_global:   return 1;
   case LangAS::opencl_constant: return 2;
   case LangAS::opencl_local:    return 3;

lib/CodeGen/CodeGenModule.cpp

@@ -2493,10 +2493,9 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
     }
   }
 
-  auto ExpectedAS =
+  LangAS ExpectedAS =
       D ? D->getType().getAddressSpace()
-        : static_cast<unsigned>(LangOpts.OpenCL ? LangAS::opencl_global
-                                                : LangAS::Default);
+        : (LangOpts.OpenCL ? LangAS::opencl_global : LangAS::Default);
   assert(getContext().getTargetAddressSpace(ExpectedAS) ==
          Ty->getPointerAddressSpace());
   if (AddrSpace != ExpectedAS)
@@ -2635,11 +2634,10 @@ CharUnits CodeGenModule::GetTargetTypeStoreSize(llvm::Type *Ty) const {
       getDataLayout().getTypeStoreSizeInBits(Ty));
 }
 
-unsigned CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D) {
-  unsigned AddrSpace;
+LangAS CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D) {
+  LangAS AddrSpace = LangAS::Default;
   if (LangOpts.OpenCL) {
-    AddrSpace = D ? D->getType().getAddressSpace()
-                  : static_cast<unsigned>(LangAS::opencl_global);
+    AddrSpace = D ? D->getType().getAddressSpace() : LangAS::opencl_global;
     assert(AddrSpace == LangAS::opencl_global ||
            AddrSpace == LangAS::opencl_constant ||
            AddrSpace == LangAS::opencl_local ||
@@ -3799,7 +3797,7 @@ ConstantAddress CodeGenModule::GetAddrOfGlobalTemporary(
       !EvalResult.hasSideEffects())
     Value = &EvalResult.Val;
 
-  unsigned AddrSpace =
+  LangAS AddrSpace =
       VD ? GetGlobalVarAddressSpace(VD) : MaterializedType.getAddressSpace();
 
   Optional<ConstantEmitter> emitter;

lib/CodeGen/CodeGenModule.h

@@ -735,7 +735,7 @@ public:
   ///
   /// For languages without explicit address spaces, if D has default address
   /// space, target-specific global or constant address space may be returned.
-  unsigned GetGlobalVarAddressSpace(const VarDecl *D);
+  LangAS GetGlobalVarAddressSpace(const VarDecl *D);
 
   /// Return the llvm::Constant for the address of the given global variable.
   /// If Ty is non-null and if the global doesn't exist, then it will be created

lib/CodeGen/CodeGenTypeCache.h

@@ -15,6 +15,7 @@
 #define LLVM_CLANG_LIB_CODEGEN_CODEGENTYPECACHE_H
 
 #include "clang/AST/CharUnits.h"
+#include "clang/Basic/AddressSpaces.h"
 #include "llvm/IR/CallingConv.h"
 
 namespace llvm {
@@ -94,7 +95,7 @@ struct CodeGenTypeCache {
     unsigned char SizeAlignInBytes;
   };
 
-  unsigned ASTAllocaAddressSpace;
+  LangAS ASTAllocaAddressSpace;
 
   CharUnits getSizeSize() const {
     return CharUnits::fromQuantity(SizeSizeInBytes);
@@ -114,7 +115,7 @@ struct CodeGenTypeCache {
   llvm::CallingConv::ID BuiltinCC;
   llvm::CallingConv::ID getBuiltinCC() const { return BuiltinCC; }
 
-  unsigned getASTAllocaAddressSpace() const { return ASTAllocaAddressSpace; }
+  LangAS getASTAllocaAddressSpace() const { return ASTAllocaAddressSpace; }
 };
 
 }  // end namespace CodeGen

lib/CodeGen/ConstantEmitter.h

@@ -40,7 +40,7 @@ private:
 
   /// The AST address space where this (non-abstract) initializer is going.
   /// Used for generating appropriate placeholders.
-  unsigned DestAddressSpace;
+  LangAS DestAddressSpace;
 
   llvm::SmallVector<std::pair<llvm::Constant *, llvm::GlobalVariable*>, 4>
     PlaceholderAddresses;
@@ -68,11 +68,9 @@ public:
   /// Try to emit the initiaizer of the given declaration as an abstract
   /// constant.  If this succeeds, the emission must be finalized.
   llvm::Constant *tryEmitForInitializer(const VarDecl &D);
-  llvm::Constant *tryEmitForInitializer(const Expr *E,
-                                        unsigned destAddrSpace,
+  llvm::Constant *tryEmitForInitializer(const Expr *E, LangAS destAddrSpace,
                                         QualType destType);
-  llvm::Constant *emitForInitializer(const APValue &value,
-                                     unsigned destAddrSpace,
+  llvm::Constant *emitForInitializer(const APValue &value, LangAS destAddrSpace,
                                      QualType destType);
 
   void finalize(llvm::GlobalVariable *global);
@@ -151,7 +149,7 @@ public:
                                   llvm::GlobalValue *placeholder);
 
 private:
-  void initializeNonAbstract(unsigned destAS) {
+  void initializeNonAbstract(LangAS destAS) {
     assert(!InitializedNonAbstract);
     InitializedNonAbstract = true;
     DestAddressSpace = destAS;

lib/CodeGen/TargetInfo.cpp

@@ -423,18 +423,17 @@ llvm::Constant *TargetCodeGenInfo::getNullPointer(const CodeGen::CodeGenModule &
   return llvm::ConstantPointerNull::get(T);
 }
 
-unsigned TargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
-                                                     const VarDecl *D) const {
+LangAS TargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
+                                                   const VarDecl *D) const {
   assert(!CGM.getLangOpts().OpenCL &&
          !(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
          "Address space agnostic languages only");
-  return D ? D->getType().getAddressSpace()
-           : static_cast<unsigned>(LangAS::Default);
+  return D ? D->getType().getAddressSpace() : LangAS::Default;
 }
 
 llvm::Value *TargetCodeGenInfo::performAddrSpaceCast(
-    CodeGen::CodeGenFunction &CGF, llvm::Value *Src, unsigned SrcAddr,
-    unsigned DestAddr, llvm::Type *DestTy, bool isNonNull) const {
+    CodeGen::CodeGenFunction &CGF, llvm::Value *Src, LangAS SrcAddr,
+    LangAS DestAddr, llvm::Type *DestTy, bool isNonNull) const {
   // Since target may map different address spaces in AST to the same address
   // space, an address space conversion may end up as a bitcast.
   if (auto *C = dyn_cast<llvm::Constant>(Src))
@@ -444,7 +443,7 @@ llvm::Value *TargetCodeGenInfo::performAddrSpaceCast(
 
 llvm::Constant *
 TargetCodeGenInfo::performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *Src,
-                                        unsigned SrcAddr, unsigned DestAddr,
+                                        LangAS SrcAddr, LangAS DestAddr,
                                         llvm::Type *DestTy) const {
   // Since target may map different address spaces in AST to the same address
   // space, an address space conversion may end up as a bitcast.
@@ -7611,12 +7610,12 @@ public:
   llvm::Constant *getNullPointer(const CodeGen::CodeGenModule &CGM,
       llvm::PointerType *T, QualType QT) const override;
 
-  unsigned getASTAllocaAddressSpace() const override {
-    return LangAS::FirstTargetAddressSpace +
-           getABIInfo().getDataLayout().getAllocaAddrSpace();
+  LangAS getASTAllocaAddressSpace() const override {
+    return getLangASFromTargetAS(
+        getABIInfo().getDataLayout().getAllocaAddrSpace());
   }
-  unsigned getGlobalVarAddressSpace(CodeGenModule &CGM,
-                                    const VarDecl *D) const override;
+  LangAS getGlobalVarAddressSpace(CodeGenModule &CGM,
+                                  const VarDecl *D) const override;
   llvm::SyncScope::ID getLLVMSyncScopeID(SyncScope S,
                                          llvm::LLVMContext &C) const override;
   llvm::Function *
@@ -7707,21 +7706,19 @@ llvm::Constant *AMDGPUTargetCodeGenInfo::getNullPointer(
       llvm::ConstantPointerNull::get(NPT), PT);
 }
 
-unsigned
+LangAS
 AMDGPUTargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
                                                   const VarDecl *D) const {
   assert(!CGM.getLangOpts().OpenCL &&
          !(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
          "Address space agnostic languages only");
-  unsigned DefaultGlobalAS =
-      LangAS::FirstTargetAddressSpace +
-      CGM.getContext().getTargetAddressSpace(LangAS::opencl_global);
+  LangAS DefaultGlobalAS = getLangASFromTargetAS(
+      CGM.getContext().getTargetAddressSpace(LangAS::opencl_global));
   if (!D)
     return DefaultGlobalAS;
 
-  unsigned AddrSpace = D->getType().getAddressSpace();
-  assert(AddrSpace == LangAS::Default ||
-         AddrSpace >= LangAS::FirstTargetAddressSpace);
+  LangAS AddrSpace = D->getType().getAddressSpace();
+  assert(AddrSpace == LangAS::Default || isTargetAddressSpace(AddrSpace));
   if (AddrSpace != LangAS::Default)
     return AddrSpace;
 

lib/CodeGen/TargetInfo.h

@@ -236,11 +236,11 @@ public:
   /// other than OpenCL and CUDA.
   /// If \p D is nullptr, returns the default target favored address space
   /// for global variable.
-  virtual unsigned getGlobalVarAddressSpace(CodeGenModule &CGM,
-                                            const VarDecl *D) const;
+  virtual LangAS getGlobalVarAddressSpace(CodeGenModule &CGM,
+                                          const VarDecl *D) const;
 
   /// Get the AST address space for alloca.
-  virtual unsigned getASTAllocaAddressSpace() const { return LangAS::Default; }
+  virtual LangAS getASTAllocaAddressSpace() const { return LangAS::Default; }
 
   /// Perform address space cast of an expression of pointer type.
   /// \param V is the LLVM value to be casted to another address space.
@@ -249,9 +249,8 @@ public:
   /// \param DestTy is the destination LLVM pointer type.
   /// \param IsNonNull is the flag indicating \p V is known to be non null.
   virtual llvm::Value *performAddrSpaceCast(CodeGen::CodeGenFunction &CGF,
-                                            llvm::Value *V, unsigned SrcAddr,
-                                            unsigned DestAddr,
-                                            llvm::Type *DestTy,
+                                            llvm::Value *V, LangAS SrcAddr,
+                                            LangAS DestAddr, llvm::Type *DestTy,
                                             bool IsNonNull = false) const;
 
   /// Perform address space cast of a constant expression of pointer type.
@@ -259,9 +258,10 @@ public:
   /// \param SrcAddr is the language address space of \p V.
   /// \param DestAddr is the targeted language address space.
   /// \param DestTy is the destination LLVM pointer type.
-  virtual llvm::Constant *
-  performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *V, unsigned SrcAddr,
-                       unsigned DestAddr, llvm::Type *DestTy) const;
+  virtual llvm::Constant *performAddrSpaceCast(CodeGenModule &CGM,
+                                               llvm::Constant *V,
+                                               LangAS SrcAddr, LangAS DestAddr,
+                                               llvm::Type *DestTy) const;
 
   /// Get the syncscope used in LLVM IR.
   virtual llvm::SyncScope::ID getLLVMSyncScopeID(SyncScope S,

lib/Sema/SemaChecking.cpp

@@ -3140,7 +3140,7 @@ ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult,
           // Treat this argument as _Nonnull as we want to show a warning if
           // NULL is passed into it.
           CheckNonNullArgument(*this, ValArg, DRE->getLocStart());
-          unsigned AS = 0;
+          LangAS AS = LangAS::Default;
           // Keep address space of non-atomic pointer type.
           if (const PointerType *PtrTy =
                   ValArg->getType()->getAs<PointerType>()) {

lib/Sema/SemaDecl.cpp

@@ -7332,8 +7332,8 @@ void Sema::CheckVariableDeclarationType(VarDecl *NewVD) {
   // This includes arrays of objects with address space qualifiers, but not
   // automatic variables that point to other address spaces.
   // ISO/IEC TR 18037 S5.1.2
-  if (!getLangOpts().OpenCL
-      && NewVD->hasLocalStorage() && T.getAddressSpace() != 0) {
+  if (!getLangOpts().OpenCL && NewVD->hasLocalStorage() &&
+      T.getAddressSpace() != LangAS::Default) {
     Diag(NewVD->getLocation(), diag::err_as_qualified_auto_decl) << 0;
     NewVD->setInvalidDecl();
     return;
@@ -8833,7 +8833,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   if (getLangOpts().OpenCL) {
     // OpenCL v1.1 s6.5: Using an address space qualifier in a function return
     // type declaration will generate a compilation error.
-    unsigned AddressSpace = NewFD->getReturnType().getAddressSpace();
+    LangAS AddressSpace = NewFD->getReturnType().getAddressSpace();
     if (AddressSpace != LangAS::Default) {
       Diag(NewFD->getLocation(),
            diag::err_opencl_return_value_with_address_space);

lib/Sema/SemaDeclAttr.cpp

@@ -4385,7 +4385,7 @@ bool Sema::CheckCallingConvAttr(const AttributeList &Attrs, CallingConv &CC,
 static bool isValidSwiftContextType(QualType type) {
   if (!type->hasPointerRepresentation())
     return type->isDependentType();
-  return type->getPointeeType().getAddressSpace() == 0;
+  return type->getPointeeType().getAddressSpace() == LangAS::Default;
 }
 
 /// Pointers and references in the default address space.
@@ -4397,7 +4397,7 @@ static bool isValidSwiftIndirectResultType(QualType type) {
   } else {
     return type->isDependentType();
   }
-  return type.getAddressSpace() == 0;
+  return type.getAddressSpace() == LangAS::Default;
 }
 
 /// Pointers and references to pointers in the default address space.

lib/Sema/SemaDeclObjC.cpp

@@ -4688,7 +4688,7 @@ VarDecl *Sema::BuildObjCExceptionDecl(TypeSourceInfo *TInfo, QualType T,
   // duration shall not be qualified by an address-space qualifier."
   // Since all parameters have automatic store duration, they can not have
   // an address space.
-  if (T.getAddressSpace() != 0) {
+  if (T.getAddressSpace() != LangAS::Default) {
     Diag(IdLoc, diag::err_arg_with_address_space);
     Invalid = true;
   }

lib/Sema/SemaExpr.cpp

@@ -5064,7 +5064,7 @@ static FunctionDecl *rewriteBuiltinFunctionDecl(Sema *Sema, ASTContext &Context,
     }
 
     NeedsNewDecl = true;
-    unsigned AS = ArgType->getPointeeType().getQualifiers().getAddressSpace();
+    LangAS AS = ArgType->getPointeeType().getAddressSpace();
 
     QualType PointeeType = ParamType->getPointeeType();
     PointeeType = Context.getAddrSpaceQualType(PointeeType, AS);
@@ -5760,8 +5760,8 @@ CastKind Sema::PrepareScalarCast(ExprResult &Src, QualType DestTy) {
   case Type::STK_ObjCObjectPointer:
     switch (DestTy->getScalarTypeKind()) {
     case Type::STK_CPointer: {
-      unsigned SrcAS = SrcTy->getPointeeType().getAddressSpace();
-      unsigned DestAS = DestTy->getPointeeType().getAddressSpace();
+      LangAS SrcAS = SrcTy->getPointeeType().getAddressSpace();
+      LangAS DestAS = DestTy->getPointeeType().getAddressSpace();
       if (SrcAS != DestAS)
         return CK_AddressSpaceConversion;
       return CK_BitCast;
@@ -6365,9 +6365,9 @@ static QualType checkConditionalPointerCompatibility(Sema &S, ExprResult &LHS,
   Qualifiers lhQual = lhptee.getQualifiers();
   Qualifiers rhQual = rhptee.getQualifiers();
 
-  unsigned ResultAddrSpace = 0;
-  unsigned LAddrSpace = lhQual.getAddressSpace();
-  unsigned RAddrSpace = rhQual.getAddressSpace();
+  LangAS ResultAddrSpace = LangAS::Default;
+  LangAS LAddrSpace = lhQual.getAddressSpace();
+  LangAS RAddrSpace = rhQual.getAddressSpace();
   if (S.getLangOpts().OpenCL) {
     // OpenCL v1.1 s6.5 - Conversion between pointers to distinct address
     // spaces is disallowed.
@@ -7649,8 +7649,8 @@ Sema::CheckAssignmentConstraints(QualType LHSType, ExprResult &RHS,
   if (const PointerType *LHSPointer = dyn_cast<PointerType>(LHSType)) {
     // U* -> T*
     if (isa<PointerType>(RHSType)) {
-      unsigned AddrSpaceL = LHSPointer->getPointeeType().getAddressSpace();
-      unsigned AddrSpaceR = RHSType->getPointeeType().getAddressSpace();
+      LangAS AddrSpaceL = LHSPointer->getPointeeType().getAddressSpace();
+      LangAS AddrSpaceR = RHSType->getPointeeType().getAddressSpace();
       Kind = AddrSpaceL != AddrSpaceR ? CK_AddressSpaceConversion : CK_BitCast;
       return checkPointerTypesForAssignment(*this, LHSType, RHSType);
     }
@@ -7685,10 +7685,10 @@ Sema::CheckAssignmentConstraints(QualType LHSType, ExprResult &RHS,
     // U^ -> void*
     if (RHSType->getAs<BlockPointerType>()) {
       if (LHSPointer->getPointeeType()->isVoidType()) {
-        unsigned AddrSpaceL = LHSPointer->getPointeeType().getAddressSpace();
-        unsigned AddrSpaceR = RHSType->getAs<BlockPointerType>()
-                                  ->getPointeeType()
-                                  .getAddressSpace();
+        LangAS AddrSpaceL = LHSPointer->getPointeeType().getAddressSpace();
+        LangAS AddrSpaceR = RHSType->getAs<BlockPointerType>()
+                                ->getPointeeType()
+                                .getAddressSpace();
         Kind =
             AddrSpaceL != AddrSpaceR ? CK_AddressSpaceConversion : CK_BitCast;
         return Compatible;
@@ -7702,12 +7702,12 @@ Sema::CheckAssignmentConstraints(QualType LHSType, ExprResult &RHS,
   if (isa<BlockPointerType>(LHSType)) {
     // U^ -> T^
     if (RHSType->isBlockPointerType()) {
-      unsigned AddrSpaceL = LHSType->getAs<BlockPointerType>()
-                                ->getPointeeType()
-                                .getAddressSpace();
-      unsigned AddrSpaceR = RHSType->getAs<BlockPointerType>()
-                                ->getPointeeType()
-                                .getAddressSpace();
+      LangAS AddrSpaceL = LHSType->getAs<BlockPointerType>()
+                              ->getPointeeType()
+                              .getAddressSpace();
+      LangAS AddrSpaceR = RHSType->getAs<BlockPointerType>()
+                              ->getPointeeType()
+                              .getAddressSpace();
       Kind = AddrSpaceL != AddrSpaceR ? CK_AddressSpaceConversion : CK_BitCast;
       return checkBlockPointerTypesForAssignment(*this, LHSType, RHSType);
     }
@@ -9804,8 +9804,8 @@ QualType Sema::CheckCompareOperands(ExprResult &LHS, ExprResult &RHS,
               << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
         }
       }
-      unsigned AddrSpaceL = LCanPointeeTy.getAddressSpace();
-      unsigned AddrSpaceR = RCanPointeeTy.getAddressSpace();
+      LangAS AddrSpaceL = LCanPointeeTy.getAddressSpace();
+      LangAS AddrSpaceR = RCanPointeeTy.getAddressSpace();
       CastKind Kind = AddrSpaceL != AddrSpaceR ? CK_AddressSpaceConversion
                                                : CK_BitCast;
       if (LHSIsNull && !RHSIsNull)

lib/Sema/SemaExprCXX.cpp

@@ -2113,7 +2113,7 @@ bool Sema::CheckAllocatedType(QualType AllocType, SourceLocation Loc,
   else if (AllocType->isVariablyModifiedType())
     return Diag(Loc, diag::err_variably_modified_new_type)
              << AllocType;
-  else if (AllocType.getAddressSpace())
+  else if (AllocType.getAddressSpace() != LangAS::Default)
     return Diag(Loc, diag::err_address_space_qualified_new)
       << AllocType.getUnqualifiedType()
       << AllocType.getQualifiers().getAddressSpaceAttributePrintValue();
@@ -3185,7 +3185,7 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
     QualType Pointee = Type->getAs<PointerType>()->getPointeeType();
     QualType PointeeElem = Context.getBaseElementType(Pointee);
 
-    if (Pointee.getAddressSpace())
+    if (Pointee.getAddressSpace() != LangAS::Default)
       return Diag(Ex.get()->getLocStart(),
                   diag::err_address_space_qualified_delete)
                << Pointee.getUnqualifiedType()

lib/Sema/SemaTemplateDeduction.cpp

@@ -1870,11 +1870,10 @@ DeduceTemplateArgumentsByTypeMatch(Sema &S,
             Deduced);
       }
 
-      if (Arg.getAddressSpace() >= LangAS::FirstTargetAddressSpace) {
+      if (isTargetAddressSpace(Arg.getAddressSpace())) {
         llvm::APSInt ArgAddressSpace(S.Context.getTypeSize(S.Context.IntTy),
                                      false);
-        ArgAddressSpace =
-            (Arg.getAddressSpace() - LangAS::FirstTargetAddressSpace);
+        ArgAddressSpace = toTargetAddressSpace(Arg.getAddressSpace());
 
         // Perform deduction on the pointer types.
         if (Sema::TemplateDeductionResult Result =

lib/Sema/SemaType.cpp

@@ -5631,7 +5631,7 @@ QualType Sema::BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
     // If this type is already address space qualified, reject it.
     // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified
     // by qualifiers for two or more different address spaces."
-    if (T.getAddressSpace()) {
+    if (T.getAddressSpace() != LangAS::Default) {
       Diag(AttrLoc, diag::err_attribute_address_multiple_qualifiers);
       return QualType();
     }
@@ -5655,15 +5655,16 @@ QualType Sema::BuildAddressSpaceAttr(QualType &T, Expr *AddrSpace,
     }
 
     llvm::APSInt max(addrSpace.getBitWidth());
-    max = Qualifiers::MaxAddressSpace - LangAS::FirstTargetAddressSpace;
+    max =
+        Qualifiers::MaxAddressSpace - (unsigned)LangAS::FirstTargetAddressSpace;
     if (addrSpace > max) {
       Diag(AttrLoc, diag::err_attribute_address_space_too_high)
           << (unsigned)max.getZExtValue() << AddrSpace->getSourceRange();
       return QualType();
     }
 
-    unsigned ASIdx = static_cast<unsigned>(addrSpace.getZExtValue()) +
-                     LangAS::FirstTargetAddressSpace;
+    LangAS ASIdx =
+        getLangASFromTargetAS(static_cast<unsigned>(addrSpace.getZExtValue()));
 
     return Context.getAddrSpaceQualType(T, ASIdx);
   }
@@ -5689,7 +5690,7 @@ static void HandleAddressSpaceTypeAttribute(QualType &Type,
   // If this type is already address space qualified, reject it.
   // ISO/IEC TR 18037 S5.3 (amending C99 6.7.3): "No type shall be qualified by
   // qualifiers for two or more different address spaces."
-  if (Type.getAddressSpace()) {
+  if (Type.getAddressSpace() != LangAS::Default) {
     S.Diag(Attr.getLoc(), diag::err_attribute_address_multiple_qualifiers);
     Attr.setInvalid();
     return;
@@ -5703,7 +5704,7 @@ static void HandleAddressSpaceTypeAttribute(QualType &Type,
     return;
   }
 
-  unsigned ASIdx;
+  LangAS ASIdx;
   if (Attr.getKind() == AttributeList::AT_AddressSpace) {
 
     // Check the attribute arguments.
@@ -7036,7 +7037,7 @@ static void deduceOpenCLImplicitAddrSpace(TypeProcessingState &State,
       (T->isVoidType() && !IsPointee))
     return;
 
-  unsigned ImpAddr;
+  LangAS ImpAddr;
   // Put OpenCL automatic variable in private address space.
   // OpenCL v1.2 s6.5:
   // The default address space name for arguments to a function in a

tools/libclang/CXType.cpp

@@ -403,7 +403,10 @@ unsigned clang_getAddressSpace(CXType CT) {
   if (T.getAddressSpace() >= LangAS::FirstTargetAddressSpace) {
     return T.getQualifiers().getAddressSpaceAttributePrintValue();
   }
-  return T.getAddressSpace();
+  // FIXME: this function returns either a LangAS or a target AS
+  // Those values can overlap which makes this function rather unpredictable
+  // for any caller
+  return (unsigned)T.getAddressSpace();
 }
 
 CXString clang_getTypedefName(CXType CT) {