Fix printing of anonymous struct typedefs

[steven_watanabe]

Summary

Currently clang -cc1 -ast-print puts the struct
definition in the wrong place, like this:

struct {} typedef S;

The reason that this happens is that the printing code
first prints the struct definition, and then tells the next
declaration to leave out the type. The current behavior
is correct for simple variable declarations, but fails for
typedefs (or extern, mutable, etc).

The patch address this problem by skipping the struct
declaration when we first see it, and then telling the first
subsequent declaration that it needs to print out the full
struct definition.

include/clang/AST/PrettyPrinter.h

 };
 
 /// \brief Describes how types, statements, expressions, and
 /// declarations should be printed.
 struct PrintingPolicy {
   /// \brief Create a default printing policy for C.
   PrintingPolicy(const LangOptions &LO)
     : LangOpts(LO), Indentation(2), SuppressSpecifiers(false),
-      SuppressTagKeyword(false), SuppressTag(false), SuppressScope(false),
+      SuppressTagKeyword(false),
+      IncludeTagDefinition(false), SuppressScope(false),
       SuppressUnwrittenScope(false), SuppressInitializers(false),
       ConstantArraySizeAsWritten(false), AnonymousTagLocations(true),
       SuppressStrongLifetime(false), SuppressLifetimeQualifiers(false),
       SuppressTemplateArgsInCXXConstructors(false),
       Bool(LO.Bool), TerseOutput(false), PolishForDeclaration(false),
       Half(LO.Half), MSWChar(LO.MicrosoftExt && !LO.WChar),
       IncludeNewlines(true), MSVCFormatting(false) { }
 
struct PrintingPolicy {
   /// This is used when printing the inner type of elaborated types,
   /// (as the tag keyword is part of the elaborated type):
   ///
   /// \code
   /// struct Geometry::Point;
   /// \endcode
   bool SuppressTagKeyword : 1;
 
-  /// \brief Whether type printing should skip printing the actual tag type.
+  /// \brief When true, include the body of a tag definition.
   ///
-  /// This is used when the caller needs to print a tag definition in front
-  /// of the type, as in constructs like the following:
+  /// This is used to place the definition of a struct
+  /// in the middle of another declaration as with:
   ///
   /// \code
   /// typedef struct { int x, y; } Point;
   /// \endcode
-  bool SuppressTag : 1;
+  bool IncludeTagDefinition : 1;
 
   /// \brief Suppresses printing of scope specifiers.
   bool SuppressScope : 1;
 
   /// \brief Suppress printing parts of scope specifiers that don't need
   /// to be written, e.g., for inline or anonymous namespaces.
   bool SuppressUnwrittenScope : 1;
   

include/clang/AST/Type.h

public:
   static std::string getAsString(SplitQualType split) {
     return getAsString(split.Ty, split.Quals);
   }
   static std::string getAsString(const Type *ty, Qualifiers qs);
 
   std::string getAsString(const PrintingPolicy &Policy) const;
 
   void print(raw_ostream &OS, const PrintingPolicy &Policy,
-             const Twine &PlaceHolder = Twine()) const {
-    print(split(), OS, Policy, PlaceHolder);
+             const Twine &PlaceHolder = Twine(),
+             unsigned Indentation = 0) const {
+    print(split(), OS, Policy, PlaceHolder, Indentation);
   }
   static void print(SplitQualType split, raw_ostream &OS,
-                    const PrintingPolicy &policy, const Twine &PlaceHolder) {
-    return print(split.Ty, split.Quals, OS, policy, PlaceHolder);
+                    const PrintingPolicy &policy, const Twine &PlaceHolder,
+                    unsigned Indentation = 0) {
+    return print(split.Ty, split.Quals, OS, policy, PlaceHolder, Indentation);
   }
   static void print(const Type *ty, Qualifiers qs,
                     raw_ostream &OS, const PrintingPolicy &policy,
-                    const Twine &PlaceHolder);
+                    const Twine &PlaceHolder,
+                    unsigned Indentation = 0);
 
   void getAsStringInternal(std::string &Str,
                            const PrintingPolicy &Policy) const {
     return getAsStringInternal(split(), Str, Policy);
   }
   static void getAsStringInternal(SplitQualType split, std::string &out,
                                   const PrintingPolicy &policy) {
     return getAsStringInternal(split.Ty, split.Quals, out, policy);
   }
   static void getAsStringInternal(const Type *ty, Qualifiers qs,
                                   std::string &out,
                                   const PrintingPolicy &policy);
 
   class StreamedQualTypeHelper {
     const QualType &T;
     const PrintingPolicy &Policy;
     const Twine &PlaceHolder;
+    unsigned Indentation;
   public:
     StreamedQualTypeHelper(const QualType &T, const PrintingPolicy &Policy,
-                           const Twine &PlaceHolder)
-      : T(T), Policy(Policy), PlaceHolder(PlaceHolder) { }
+                           const Twine &PlaceHolder, unsigned Indentation)
+      : T(T), Policy(Policy), PlaceHolder(PlaceHolder),
+        Indentation(Indentation) { }
 
     friend raw_ostream &operator<<(raw_ostream &OS,
                                    const StreamedQualTypeHelper &SQT) {
-      SQT.T.print(OS, SQT.Policy, SQT.PlaceHolder);
+      SQT.T.print(OS, SQT.Policy, SQT.PlaceHolder, SQT.Indentation);
       return OS;
     }
   };
 
   StreamedQualTypeHelper stream(const PrintingPolicy &Policy,
-                                const Twine &PlaceHolder = Twine()) const {
-    return StreamedQualTypeHelper(*this, Policy, PlaceHolder);
+                                const Twine &PlaceHolder = Twine(),
+                                unsigned Indentation = 0) const {
+    return StreamedQualTypeHelper(*this, Policy, PlaceHolder, Indentation);
   }
 
   void dump(const char *s) const;
   void dump() const;
 
   void Profile(llvm::FoldingSetNodeID &ID) const {
     ID.AddPointer(getAsOpaquePtr());
   }

lib/AST/DeclPrinter.cpp

void Decl::printGroup(Decl** Begin, unsigned NumDecls,
   }
 
   Decl** End = Begin + NumDecls;
   TagDecl* TD = dyn_cast<TagDecl>(*Begin);
   if (TD)
     ++Begin;
 
   PrintingPolicy SubPolicy(Policy);
-  if (TD && TD->isCompleteDefinition()) {
-    TD->print(Out, Policy, Indentation);
-    Out << " ";
-    SubPolicy.SuppressTag = true;
-  }
 
   bool isFirst = true;
   for ( ; Begin != End; ++Begin) {
     if (isFirst) {
+      if(TD)
+        SubPolicy.IncludeTagDefinition = true;
       SubPolicy.SuppressSpecifiers = false;
       isFirst = false;
     } else {
       if (!isFirst) Out << ", ";
+      SubPolicy.IncludeTagDefinition = false;
       SubPolicy.SuppressSpecifiers = true;
     }
 
     (*Begin)->print(Out, SubPolicy, Indentation);
   }
 }
 
 LLVM_DUMP_METHOD void DeclContext::dumpDeclContext() const {

 void DeclPrinter::printDeclType(QualType T, StringRef DeclName, bool Pack) {
   // Normally, a PackExpansionType is written as T[3]... (for instance, as a
   // template argument), but if it is the type of a declaration, the ellipsis
   // is placed before the name being declared.
   if (auto *PET = T->getAs<PackExpansionType>()) {
     Pack = true;
     T = PET->getPattern();
   }
-  T.print(Out, Policy, (Pack ? "..." : "") + DeclName);
+  T.print(Out, Policy, (Pack ? "..." : "") + DeclName, Indentation);
 }
 
 void DeclPrinter::ProcessDeclGroup(SmallVectorImpl<Decl*>& Decls) {
   this->Indent();
   Decl::printGroup(Decls.data(), Decls.size(), Out, Policy, Indentation);
   Out << ";\n";
   Decls.clear();
 

 
 void DeclPrinter::VisitTypedefDecl(TypedefDecl *D) {
   if (!Policy.SuppressSpecifiers) {
     Out << "typedef ";
     
     if (D->isModulePrivate())
       Out << "__module_private__ ";
   }
-  D->getTypeSourceInfo()->getType().print(Out, Policy, D->getName());
+  QualType Ty = D->getTypeSourceInfo()->getType();
+  Ty.print(Out, Policy, D->getName(), Indentation);
   prettyPrintAttributes(D);
 }
 
 void DeclPrinter::VisitTypeAliasDecl(TypeAliasDecl *D) {
   Out << "using " << *D;
   prettyPrintAttributes(D);
   Out << " = " << D->getTypeSourceInfo()->getType().getAsString(Policy);
 }

 void DeclPrinter::VisitFieldDecl(FieldDecl *D) {
   // FIXME: add printing of pragma attributes if required.
   if (!Policy.SuppressSpecifiers && D->isMutable())
     Out << "mutable ";
   if (!Policy.SuppressSpecifiers && D->isModulePrivate())
     Out << "__module_private__ ";
 
   Out << D->getASTContext().getUnqualifiedObjCPointerType(D->getType()).
-            stream(Policy, D->getName());
+         stream(Policy, D->getName(), Indentation);
 
   if (D->isBitField()) {
     Out << " : ";
     D->getBitWidth()->printPretty(Out, nullptr, Policy, Indentation);
   }
 
   Expr *Init = D->getInClassInitializer();
   if (!Policy.SuppressInitializers && Init) {
if (!Policy.SuppressInitializers && Init) {
     if (!ImplicitInit) {
       if ((D->getInitStyle() == VarDecl::CallInit) && !isa<ParenListExpr>(Init))
         Out << "(";
       else if (D->getInitStyle() == VarDecl::CInit) {
         Out << " = ";
       }
       PrintingPolicy SubPolicy(Policy);
       SubPolicy.SuppressSpecifiers = false;
-      SubPolicy.SuppressTag = false;
+      SubPolicy.IncludeTagDefinition = false;
       Init->printPretty(Out, nullptr, SubPolicy, Indentation);
       if ((D->getInitStyle() == VarDecl::CallInit) && !isa<ParenListExpr>(Init))
         Out << ")";
     }
   }
   prettyPrintAttributes(D);
 }
 

lib/AST/TypePrinter.cpp

public:
     ~ElaboratedTypePolicyRAII() {
       Policy.SuppressTagKeyword = SuppressTagKeyword;
       Policy.SuppressScope = SuppressScope;
     }
   };
   
   class TypePrinter {
     PrintingPolicy Policy;
+    unsigned Indentation;
     bool HasEmptyPlaceHolder;
     bool InsideCCAttribute;
 
   public:
-    explicit TypePrinter(const PrintingPolicy &Policy)
-      : Policy(Policy), HasEmptyPlaceHolder(false), InsideCCAttribute(false) { }
+    explicit TypePrinter(const PrintingPolicy &Policy, unsigned Indentation = 0)
+      : Policy(Policy), Indentation(Indentation),
+        HasEmptyPlaceHolder(false), InsideCCAttribute(false) { }
 
     void print(const Type *ty, Qualifiers qs, raw_ostream &OS,
                StringRef PlaceHolder);
     void print(QualType T, raw_ostream &OS, StringRef PlaceHolder);
 
     static bool canPrefixQualifiers(const Type *T, bool &NeedARCStrongQualifier);
     void spaceBeforePlaceHolder(raw_ostream &OS);
     void printTypeSpec(const NamedDecl *D, raw_ostream &OS);
void TypePrinter::printMemberPointerBefore(const MemberPointerType *T,
   SaveAndRestore<bool> NonEmptyPH(HasEmptyPlaceHolder, false);
   printBefore(T->getPointeeType(), OS);
   // Handle things like 'int (Cls::*A)[4];' correctly.
   // FIXME: this should include vectors, but vectors use attributes I guess.
   if (isa<ArrayType>(T->getPointeeType()))
     OS << '(';
 
   PrintingPolicy InnerPolicy(Policy);
-  InnerPolicy.SuppressTag = false;
+  InnerPolicy.IncludeTagDefinition = false;
   TypePrinter(InnerPolicy).print(QualType(T->getClass(), 0), OS, StringRef());
 
   OS << "::*";
 }
 void TypePrinter::printMemberPointerAfter(const MemberPointerType *T, 
                                           raw_ostream &OS) { 
   IncludeStrongLifetimeRAII Strong(Policy);
   SaveAndRestore<bool> NonEmptyPH(HasEmptyPlaceHolder, false);
if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(DC)) {
     else if (Tag->getIdentifier())
       OS << Tag->getIdentifier()->getName() << "::";
     else
       return;
   }
 }
 
 void TypePrinter::printTag(TagDecl *D, raw_ostream &OS) {
-  if (Policy.SuppressTag)
+  if (Policy.IncludeTagDefinition) {
+    PrintingPolicy SubPolicy = Policy;
+    SubPolicy.IncludeTagDefinition = false;
+    D->print(OS, SubPolicy, Indentation);
+    spaceBeforePlaceHolder(OS);
     return;
+  }
 
   bool HasKindDecoration = false;
 
   // bool SuppressTagKeyword
   //   = Policy.LangOpts.CPlusPlus || Policy.SuppressTagKeyword;
 
   // We don't print tags unless this is an elaborated type.
   // In C, we just assume every RecordType is an elaborated type.
void TypePrinter::printInjectedClassNameBefore(const InjectedClassNameType *T,
                                                raw_ostream &OS) {
   printTemplateSpecializationBefore(T->getInjectedTST(), OS);
 }
 void TypePrinter::printInjectedClassNameAfter(const InjectedClassNameType *T,
                                                raw_ostream &OS) { }
 
 void TypePrinter::printElaboratedBefore(const ElaboratedType *T,
                                         raw_ostream &OS) {
-  if (Policy.SuppressTag && isa<TagType>(T->getNamedType()))
-    return;
+  // The tag definition will take care of these.
+  if (!Policy.IncludeTagDefinition)
+  {
     OS << TypeWithKeyword::getKeywordName(T->getKeyword());
     if (T->getKeyword() != ETK_None)
       OS << " ";
     NestedNameSpecifier* Qualifier = T->getQualifier();
     if (Qualifier)
       Qualifier->print(OS, Policy);
+  }
   
   ElaboratedTypePolicyRAII PolicyRAII(Policy);
   printBefore(T->getNamedType(), OS);
 }
 void TypePrinter::printElaboratedAfter(const ElaboratedType *T,
                                         raw_ostream &OS) {
   ElaboratedTypePolicyRAII PolicyRAII(Policy);
   printAfter(T->getNamedType(), OS);
std::string QualType::getAsString(const Type *ty, Qualifiers qs) {
   std::string buffer;
   LangOptions options;
   getAsStringInternal(ty, qs, buffer, PrintingPolicy(options));
   return buffer;
 }
 
 void QualType::print(const Type *ty, Qualifiers qs,
                      raw_ostream &OS, const PrintingPolicy &policy,
-                     const Twine &PlaceHolder) {
+                     const Twine &PlaceHolder, unsigned Indentation) {
   SmallString<128> PHBuf;
   StringRef PH = PlaceHolder.toStringRef(PHBuf);
 
-  TypePrinter(policy).print(ty, qs, OS, PH);
+  TypePrinter(policy, Indentation).print(ty, qs, OS, PH);
 }
 
 void QualType::getAsStringInternal(const Type *ty, Qualifiers qs,
                                    std::string &buffer,
                                    const PrintingPolicy &policy) {
   SmallString<256> Buf;
   llvm::raw_svector_ostream StrOS(Buf);
   TypePrinter(policy).print(ty, qs, StrOS, buffer);
   std::string str = StrOS.str();
   buffer.swap(str);
 }

test/Sema/ast-print.c

 // RUN: %clang_cc1 %s -ast-print | FileCheck %s
+// RUN: %clang_cc1 %s -ast-print | %clang_cc1 -fsyntax-only -
 
 typedef void func_typedef();
 func_typedef xxx;
 
 typedef void func_t(int x);
 func_t a;
 
 struct blah {
int varr(int n, int a[static n]) {
   return a[2];
 }
 
 int rvarr(int n, int a[restrict static n]) {
   // CHECK: int a[restrict static n]
   return a[2];
 }
 
+// CHECK: typedef struct {
 typedef struct {
   int f;
 } T __attribute__ ((__aligned__));
 
 // CHECK: struct __attribute__((visibility("default"))) S;
 struct __attribute__((visibility("default"))) S;
 
 struct pair_t {