Fix for PR8901: attribute "mode" rejected for enums and dependent types.

Allow "mode" attribute for enum types, except for vector modes, for compatibility with GCC.
Support "mode" attribute with dependent types.

Differential Revision: http://reviews.llvm.org/D16219

llvm-svn: 259497

clang/include/clang/Basic/Attr.td

@@ -879,8 +879,8 @@ def MipsInterrupt : InheritableAttr, TargetSpecificAttr<TargetMips> {
 
 def Mode : Attr {
   let Spellings = [GCC<"mode">];
-  let Subjects = SubjectList<[Var, TypedefName, Field], ErrorDiag,
-                             "ExpectedVariableFieldOrTypedef">;
+  let Subjects = SubjectList<[Var, Enum, TypedefName, Field], ErrorDiag,
+                             "ExpectedVariableEnumFieldOrTypedef">;
   let Args = [IdentifierArgument<"Mode">];
   let Documentation = [Undocumented];
 }

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -2448,7 +2448,7 @@ def warn_attribute_wrong_decl_type : Warning<
   "variables, functions and classes|Objective-C protocols|"
   "functions and global variables|structs, unions, and typedefs|structs and typedefs|"
   "interface or protocol declarations|kernel functions|non-K&R-style functions|"
-  "variables, fields and typedefs}1">,
+  "variables, enums, fields and typedefs}1">,
   InGroup<IgnoredAttributes>;
 def err_attribute_wrong_decl_type : Error<warn_attribute_wrong_decl_type.Text>;
 def warn_type_attribute_wrong_type : Warning<
@@ -2858,6 +2858,8 @@ def warn_vector_mode_deprecated : Warning<
   InGroup<DeprecatedAttributes>;
 def err_complex_mode_vector_type : Error<
   "type of machine mode does not support base vector types">;
+def err_enum_mode_vector_type : Error<
+  "mode %0 is not supported for enumeration types">;
 def warn_attribute_nonnull_no_pointers : Warning<
   "'nonnull' attribute applied to function with no pointer arguments">,
   InGroup<IgnoredAttributes>;

clang/include/clang/Sema/AttributeList.h

@@ -856,7 +856,7 @@ enum AttributeDeclKind {
   ExpectedObjectiveCInterfaceOrProtocol,
   ExpectedKernelFunction,
   ExpectedFunctionWithProtoType,
-  ExpectedVariableFieldOrTypedef
+  ExpectedVariableEnumFieldOrTypedef
 };
 
 }  // end namespace clang

clang/include/clang/Sema/Sema.h

@@ -7750,6 +7750,10 @@ class Sema {
   void AddLaunchBoundsAttr(SourceRange AttrRange, Decl *D, Expr *MaxThreads,
                            Expr *MinBlocks, unsigned SpellingListIndex);
 
+  /// AddModeAttr - Adds a mode attribute to a particular declaration.
+  void AddModeAttr(SourceRange AttrRange, Decl *D, IdentifierInfo *Name,
+                   unsigned SpellingListIndex, bool InInstantiation = false);
+
   //===--------------------------------------------------------------------===//
   // C++ Coroutines TS
   //

clang/lib/Sema/SemaDeclAttr.cpp

@@ -3297,6 +3297,8 @@ bool Sema::checkMSInheritanceAttrOnDefinition(
 /// attribute.
 static void parseModeAttrArg(Sema &S, StringRef Str, unsigned &DestWidth,
                              bool &IntegerMode, bool &ComplexMode) {
+  IntegerMode = true;
+  ComplexMode = false;
   switch (Str.size()) {
   case 2:
     switch (Str[0]) {
@@ -3363,9 +3365,15 @@ static void handleModeAttr(Sema &S, Decl *D, const AttributeList &Attr) {
   }
 
   IdentifierInfo *Name = Attr.getArgAsIdent(0)->Ident;
-  StringRef Str = Name->getName();
 
+  S.AddModeAttr(Attr.getRange(), D, Name, Attr.getAttributeSpellingListIndex());
+}
+
+void Sema::AddModeAttr(SourceRange AttrRange, Decl *D, IdentifierInfo *Name,
+                       unsigned SpellingListIndex, bool InInstantiation) {
+  StringRef Str = Name->getName();
   normalizeName(Str);
+  SourceLocation AttrLoc = AttrRange.getBegin();
 
   unsigned DestWidth = 0;
   bool IntegerMode = true;
@@ -3381,99 +3389,126 @@ static void handleModeAttr(Sema &S, Decl *D, const AttributeList &Attr) {
     if (VectorStringLength &&
         !Str.substr(1, VectorStringLength).getAsInteger(10, VectorSize) &&
         VectorSize.isPowerOf2()) {
-      parseModeAttrArg(S, Str.substr(VectorStringLength + 1), DestWidth,
+      parseModeAttrArg(*this, Str.substr(VectorStringLength + 1), DestWidth,
                        IntegerMode, ComplexMode);
-      S.Diag(Attr.getLoc(), diag::warn_vector_mode_deprecated);
+      // Avoid duplicate warning from template instantiation.
+      if (!InInstantiation)
+        Diag(AttrLoc, diag::warn_vector_mode_deprecated);
     } else {
       VectorSize = 0;
     }
   }
 
   if (!VectorSize)
-    parseModeAttrArg(S, Str, DestWidth, IntegerMode, ComplexMode);
+    parseModeAttrArg(*this, Str, DestWidth, IntegerMode, ComplexMode);
+
+  // FIXME: Sync this with InitializePredefinedMacros; we need to match int8_t
+  // and friends, at least with glibc.
+  // FIXME: Make sure floating-point mappings are accurate
+  // FIXME: Support XF and TF types
+  if (!DestWidth) {
+    Diag(AttrLoc, diag::err_machine_mode) << 0 /*Unknown*/ << Name;
+    return;
+  }
 
   QualType OldTy;
   if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D))
     OldTy = TD->getUnderlyingType();
-  else
+  else if (EnumDecl *ED = dyn_cast<EnumDecl>(D)) {
+    // Something like 'typedef enum { X } __attribute__((mode(XX))) T;'.
+    // Try to get type from enum declaration, default to int.
+    OldTy = ED->getIntegerType();
+    if (OldTy.isNull())
+      OldTy = Context.IntTy;
+  } else
     OldTy = cast<ValueDecl>(D)->getType();
 
+  if (OldTy->isDependentType()) {
+    D->addAttr(::new (Context)
+               ModeAttr(AttrRange, Context, Name, SpellingListIndex));
+    return;
+  }
+
   // Base type can also be a vector type (see PR17453).
   // Distinguish between base type and base element type.
   QualType OldElemTy = OldTy;
   if (const VectorType *VT = OldTy->getAs<VectorType>())
     OldElemTy = VT->getElementType();
 
-  if (!OldElemTy->getAs<BuiltinType>() && !OldElemTy->isComplexType())
-    S.Diag(Attr.getLoc(), diag::err_mode_not_primitive);
+  // GCC allows 'mode' attribute on enumeration types (even incomplete), except
+  // for vector modes. So, 'enum X __attribute__((mode(QI)));' forms a complete
+  // type, 'enum { A } __attribute__((mode(V4SI)))' is rejected.
+  if ((isa<EnumDecl>(D) || OldElemTy->getAs<EnumType>()) &&
+      VectorSize.getBoolValue()) {
+    Diag(AttrLoc, diag::err_enum_mode_vector_type) << Name << AttrRange;
+    return;
+  }
+  bool IntegralOrAnyEnumType =
+      OldElemTy->isIntegralOrEnumerationType() || OldElemTy->getAs<EnumType>();
+
+  if (!OldElemTy->getAs<BuiltinType>() && !OldElemTy->isComplexType() &&
+      !IntegralOrAnyEnumType)
+    Diag(AttrLoc, diag::err_mode_not_primitive);
   else if (IntegerMode) {
-    if (!OldElemTy->isIntegralOrEnumerationType())
-      S.Diag(Attr.getLoc(), diag::err_mode_wrong_type);
+    if (!IntegralOrAnyEnumType)
+      Diag(AttrLoc, diag::err_mode_wrong_type);
   } else if (ComplexMode) {
     if (!OldElemTy->isComplexType())
-      S.Diag(Attr.getLoc(), diag::err_mode_wrong_type);
+      Diag(AttrLoc, diag::err_mode_wrong_type);
   } else {
     if (!OldElemTy->isFloatingType())
-      S.Diag(Attr.getLoc(), diag::err_mode_wrong_type);
-  }
-
-  // FIXME: Sync this with InitializePredefinedMacros; we need to match int8_t
-  // and friends, at least with glibc.
-  // FIXME: Make sure floating-point mappings are accurate
-  // FIXME: Support XF and TF types
-  if (!DestWidth) {
-    S.Diag(Attr.getLoc(), diag::err_machine_mode) << 0 /*Unknown*/ << Name;
-    return;
+      Diag(AttrLoc, diag::err_mode_wrong_type);
   }
 
   QualType NewElemTy;
 
   if (IntegerMode)
-    NewElemTy = S.Context.getIntTypeForBitwidth(
-        DestWidth, OldElemTy->isSignedIntegerType());
+    NewElemTy = Context.getIntTypeForBitwidth(DestWidth,
+                                              OldElemTy->isSignedIntegerType());
   else
-    NewElemTy = S.Context.getRealTypeForBitwidth(DestWidth);
+    NewElemTy = Context.getRealTypeForBitwidth(DestWidth);
 
   if (NewElemTy.isNull()) {
-    S.Diag(Attr.getLoc(), diag::err_machine_mode) << 1 /*Unsupported*/ << Name;
+    Diag(AttrLoc, diag::err_machine_mode) << 1 /*Unsupported*/ << Name;
     return;
   }
 
   if (ComplexMode) {
-    NewElemTy = S.Context.getComplexType(NewElemTy);
+    NewElemTy = Context.getComplexType(NewElemTy);
   }
 
   QualType NewTy = NewElemTy;
   if (VectorSize.getBoolValue()) {
-    NewTy = S.Context.getVectorType(NewTy, VectorSize.getZExtValue(),
-                                    VectorType::GenericVector);
+    NewTy = Context.getVectorType(NewTy, VectorSize.getZExtValue(),
+                                  VectorType::GenericVector);
   } else if (const VectorType *OldVT = OldTy->getAs<VectorType>()) {
     // Complex machine mode does not support base vector types.
     if (ComplexMode) {
-      S.Diag(Attr.getLoc(), diag::err_complex_mode_vector_type);
+      Diag(AttrLoc, diag::err_complex_mode_vector_type);
       return;
     }
-    unsigned NumElements = S.Context.getTypeSize(OldElemTy) *
+    unsigned NumElements = Context.getTypeSize(OldElemTy) *
                            OldVT->getNumElements() /
-                           S.Context.getTypeSize(NewElemTy);
+                           Context.getTypeSize(NewElemTy);
     NewTy =
-        S.Context.getVectorType(NewElemTy, NumElements, OldVT->getVectorKind());
+        Context.getVectorType(NewElemTy, NumElements, OldVT->getVectorKind());
   }
 
   if (NewTy.isNull()) {
-    S.Diag(Attr.getLoc(), diag::err_mode_wrong_type);
+    Diag(AttrLoc, diag::err_mode_wrong_type);
     return;
   }
 
   // Install the new type.
   if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D))
     TD->setModedTypeSourceInfo(TD->getTypeSourceInfo(), NewTy);
+  else if (EnumDecl *ED = dyn_cast<EnumDecl>(D))
+    ED->setIntegerType(NewTy);
   else
     cast<ValueDecl>(D)->setType(NewTy);
 
-  D->addAttr(::new (S.Context)
-             ModeAttr(Attr.getRange(), S.Context, Name,
-                      Attr.getAttributeSpellingListIndex()));
+  D->addAttr(::new (Context)
+             ModeAttr(AttrRange, Context, Name, SpellingListIndex));
 }
 
 static void handleNoDebugAttr(Sema &S, Decl *D, const AttributeList &Attr) {

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -227,6 +227,14 @@ static void instantiateDependentCUDALaunchBoundsAttr(
                         Attr.getSpellingListIndex());
 }
 
+static void
+instantiateDependentModeAttr(Sema &S,
+                             const MultiLevelTemplateArgumentList &TemplateArgs,
+                             const ModeAttr &Attr, Decl *New) {
+  S.AddModeAttr(Attr.getRange(), New, Attr.getMode(),
+                Attr.getSpellingListIndex(), /*InInstantiation=*/true);
+}
+
 void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
                             const Decl *Tmpl, Decl *New,
                             LateInstantiatedAttrVec *LateAttrs,
@@ -265,6 +273,11 @@ void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
       continue;
     }
 
+    if (const ModeAttr *Mode = dyn_cast<ModeAttr>(TmplAttr)) {
+      instantiateDependentModeAttr(*this, TemplateArgs, *Mode, New);
+      continue;
+    }
+
     // Existing DLL attribute on the instantiation takes precedence.
     if (TmplAttr->getKind() == attr::DLLExport ||
         TmplAttr->getKind() == attr::DLLImport) {

clang/test/CodeGen/attr-mode-enums.c

@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm %s -o - | FileCheck %s
+
+// Test checks that 'mode' attribute is handled correctly with enums, i. e. code
+//   1. "typedef enum { A } __attribute__((mode(HI))) T;" is accepted,
+//   2. "enum X __attribute__((mode(QI))) var;" forms a complete integer type.
+
+int main() {
+  // CHECK: [[X1:%.+]] = alloca i8
+  enum { A1, B1 } __attribute__((mode(QI))) x1 = A1;
+
+  // CHECK: [[X2:%.+]] = alloca i16
+  enum { A2, B2 } x2 __attribute__((mode(HI))) = B2;
+
+  // CHECK: [[X3:%.+]] = alloca i32
+  typedef enum { A3, B3 } __attribute__((mode(SI))) T3;
+  T3 x3 = A3;
+
+  // CHECK: [[X4:%.+]] = alloca i64
+  typedef enum { A4, B4 } T4 __attribute__((mode(DI)));
+  T4 x4 = B4;
+
+  // CHECK: [[X5:%.+]] = alloca i8
+  typedef enum __attribute__((mode(QI))) { A5, B5 } T5;
+  T5 x5 = A5;
+
+  // CHECK: [[X6:%.+]] = alloca i8
+  typedef enum X __attribute__((mode(QI))) T6;
+  T6 x6;
+
+  // CHECK: [[X7:%.+]] = alloca i128
+  enum { A7, B7 } __attribute__((mode(TI))) x7 = A7;
+
+  // CHECK: [[X8:%.+]] = alloca i8
+  enum __attribute__((mode(QI))) { A8, B8 } x8 = B8;
+
+  // CHECK: store i8 0, i8* [[X1]]
+  // CHECK: store i16 1, i16* [[X2]]
+  // CHECK: store i32 0, i32* [[X3]]
+  // CHECK: store i64 1, i64* [[X4]]
+  // CHECK: store i8 0, i8* [[X5]]
+  // CHECK: store i128 0, i128* [[X7]]
+  // CHECK: store i8 1, i8* [[X8]]
+
+  return x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8;
+}