StmtPrinter: allow customizing the end-of-line character

[george.karpenkov]

Summary

Some environments need a different end-of-line character, namely, dot graphs.
There, "\l" must be used to left-adjust the printed text, as "\n" centers everything printed.

[NoQ]

Looks great to me and pretty trivial, should somebody who's more familiar with this code take a look?

clang/lib/AST/StmtPrinter.cpp

72

This variable is used so many times, maybe give it a shorter name?

clang/include/clang/AST/Stmt.h

public:
   /// dumpColor - same as dump(), but forces color highlighting.
   void dumpColor() const;
 
   /// dumpPretty/printPretty - These two methods do a "pretty print" of the AST
   /// back to its original source language syntax.
   void dumpPretty(const ASTContext &Context) const;
   void printPretty(raw_ostream &OS, PrinterHelper *Helper,
                    const PrintingPolicy &Policy, unsigned Indentation = 0,
+                   StringRef NewlineSymbol = "\n",
                    const ASTContext *Context = nullptr) const;
 
   /// viewAST - Visualize an AST rooted at this Stmt* using GraphViz.  Only
   ///   works on systems with GraphViz (Mac OS X) or dot+gv installed.
   void viewAST() const;
 
   /// Skip past any implicit AST nodes which might surround this
   /// statement, such as ExprWithCleanups or ImplicitCastExpr nodes.

clang/lib/AST/DeclPrinter.cpp

void DeclPrinter::VisitRecordDecl(RecordDecl *D) {
   }
 }
 
 void DeclPrinter::VisitEnumConstantDecl(EnumConstantDecl *D) {
   Out << *D;
   prettyPrintAttributes(D);
   if (Expr *Init = D->getInitExpr()) {
     Out << " = ";
-    Init->printPretty(Out, nullptr, Policy, Indentation, &Context);
+    Init->printPretty(Out, nullptr, Policy, Indentation, "\n", &Context);
   }
 }
 
 void DeclPrinter::VisitFunctionDecl(FunctionDecl *D) {
   if (!D->getDescribedFunctionTemplate() &&
       !D->isFunctionTemplateSpecialization())
     prettyPrintPragmas(D);
 

clang/lib/AST/StmtPrinter.cpp

 
 namespace {
 
   class StmtPrinter : public StmtVisitor<StmtPrinter> {
     raw_ostream &OS;
     unsigned IndentLevel;
     PrinterHelper* Helper;
     PrintingPolicy Policy;
+    std::string NewlineSymbol;
     const ASTContext *Context;
 
   public:
     StmtPrinter(raw_ostream &os, PrinterHelper *helper,
                 const PrintingPolicy &Policy, unsigned Indentation = 0,
+                StringRef NewlineSymbol = "\n",
                 const ASTContext *Context = nullptr)
         : OS(os), IndentLevel(Indentation), Helper(helper), Policy(Policy),
-          Context(Context) {}
+          NewlineSymbol(NewlineSymbol), Context(Context) {}
 
     void PrintStmt(Stmt *S) {
       PrintStmt(S, Policy.Indentation);
     }
 
     void PrintStmt(Stmt *S, int SubIndent) {
       IndentLevel += SubIndent;
       if (S && isa<Expr>(S)) {
         // If this is an expr used in a stmt context, indent and newline it.
         Indent();
         Visit(S);
-        OS << ";\n";
+        OS << ";" << NewlineSymbol;
       } else if (S) {
         Visit(S);
       } else {
-        Indent() << "<<<NULL STATEMENT>>>\n";
+        Indent() << "<<<NULL STATEMENT>>>" << NewlineSymbol;
       }
       IndentLevel -= SubIndent;
     }
 
     void PrintRawCompoundStmt(CompoundStmt *S);
     void PrintRawDecl(Decl *D);
     void PrintRawDeclStmt(const DeclStmt *S);
     void PrintRawIfStmt(IfStmt *If);
public:
 
     void Visit(Stmt* S) {
       if (Helper && Helper->handledStmt(S,OS))
           return;
       else StmtVisitor<StmtPrinter>::Visit(S);
     }
 
     void VisitStmt(Stmt *Node) LLVM_ATTRIBUTE_UNUSED {
-      Indent() << "<<unknown stmt type>>\n";
+      Indent() << "<<unknown stmt type>>" << NewlineSymbol;
     }
 
     void VisitExpr(Expr *Node) LLVM_ATTRIBUTE_UNUSED {
       OS << "<<unknown expr type>>";
     }
 
     void VisitCXXNamedCastExpr(CXXNamedCastExpr *Node);
 
 #define ABSTRACT_STMT(CLASS)
 #define STMT(CLASS, PARENT) \
     void Visit##CLASS(CLASS *Node);
 #include "clang/AST/StmtNodes.inc"
   };
 
 } // namespace
 
 //===----------------------------------------------------------------------===//
 //  Stmt printing methods.
 //===----------------------------------------------------------------------===//
 
 /// PrintRawCompoundStmt - Print a compound stmt without indenting the {, and
 /// with no newline after the }.
 void StmtPrinter::PrintRawCompoundStmt(CompoundStmt *Node) {
-  OS << "{\n";
+  OS << "{" << NewlineSymbol;
   for (auto *I : Node->body())
     PrintStmt(I);
 
   Indent() << "}";
 }
 
 void StmtPrinter::PrintRawDecl(Decl *D) {
   D->print(OS, Policy, IndentLevel);
 }
 
 void StmtPrinter::PrintRawDeclStmt(const DeclStmt *S) {
   SmallVector<Decl *, 2> Decls(S->decls());
   Decl::printGroup(Decls.data(), Decls.size(), OS, Policy, IndentLevel);
 }
 
 void StmtPrinter::VisitNullStmt(NullStmt *Node) {
-  Indent() << ";\n";
+  Indent() << ";" << NewlineSymbol;
 }
 
 void StmtPrinter::VisitDeclStmt(DeclStmt *Node) {
   Indent();
   PrintRawDeclStmt(Node);
-  OS << ";\n";
+  OS << ";" << NewlineSymbol;
 }
 
 void StmtPrinter::VisitCompoundStmt(CompoundStmt *Node) {
   Indent();
   PrintRawCompoundStmt(Node);
-  OS << "\n";
+  OS << "" << NewlineSymbol;
 }
 
 void StmtPrinter::VisitCaseStmt(CaseStmt *Node) {
   Indent(-1) << "case ";
   PrintExpr(Node->getLHS());
   if (Node->getRHS()) {
     OS << " ... ";
     PrintExpr(Node->getRHS());
   }
-  OS << ":\n";
+  OS << ":" << NewlineSymbol;
 
   PrintStmt(Node->getSubStmt(), 0);
 }
 
 void StmtPrinter::VisitDefaultStmt(DefaultStmt *Node) {
-  Indent(-1) << "default:\n";
+  Indent(-1) << "default:" << NewlineSymbol;
   PrintStmt(Node->getSubStmt(), 0);
 }
 
 void StmtPrinter::VisitLabelStmt(LabelStmt *Node) {
-  Indent(-1) << Node->getName() << ":\n";
+  Indent(-1) << Node->getName() << ":" << NewlineSymbol;
   PrintStmt(Node->getSubStmt(), 0);
 }
 
 void StmtPrinter::VisitAttributedStmt(AttributedStmt *Node) {
   for (const auto *Attr : Node->getAttrs()) {
     Attr->printPretty(OS, Policy);
   }
 
   PrintStmt(Node->getSubStmt(), 0);
 }
 
 void StmtPrinter::PrintRawIfStmt(IfStmt *If) {
   OS << "if (";
   if (const DeclStmt *DS = If->getConditionVariableDeclStmt())
     PrintRawDeclStmt(DS);
   else
     PrintExpr(If->getCond());
   OS << ')';
 
   if (auto *CS = dyn_cast<CompoundStmt>(If->getThen())) {
     OS << ' ';
     PrintRawCompoundStmt(CS);
-    OS << (If->getElse() ? ' ' : '\n');
+    OS << (If->getElse() ? " " : NewlineSymbol);
   } else {
-    OS << '\n';
+    OS << NewlineSymbol;
     PrintStmt(If->getThen());
     if (If->getElse()) Indent();
   }
 
   if (Stmt *Else = If->getElse()) {
     OS << "else";
 
     if (auto *CS = dyn_cast<CompoundStmt>(Else)) {
       OS << ' ';
       PrintRawCompoundStmt(CS);
-      OS << '\n';
+      OS << NewlineSymbol;
     } else if (auto *ElseIf = dyn_cast<IfStmt>(Else)) {
       OS << ' ';
       PrintRawIfStmt(ElseIf);
     } else {
-      OS << '\n';
+      OS << NewlineSymbol;
       PrintStmt(If->getElse());
     }
   }
 }
 
 void StmtPrinter::VisitIfStmt(IfStmt *If) {
   Indent();
   PrintRawIfStmt(If);
 }
 
 void StmtPrinter::VisitSwitchStmt(SwitchStmt *Node) {
   Indent() << "switch (";
   if (const DeclStmt *DS = Node->getConditionVariableDeclStmt())
     PrintRawDeclStmt(DS);
   else
     PrintExpr(Node->getCond());
   OS << ")";
 
   // Pretty print compoundstmt bodies (very common).
   if (auto *CS = dyn_cast<CompoundStmt>(Node->getBody())) {
     OS << " ";
     PrintRawCompoundStmt(CS);
-    OS << "\n";
+    OS << NewlineSymbol;
   } else {
-    OS << "\n";
+    OS << NewlineSymbol;
     PrintStmt(Node->getBody());
   }
 }
 
 void StmtPrinter::VisitWhileStmt(WhileStmt *Node) {
   Indent() << "while (";
   if (const DeclStmt *DS = Node->getConditionVariableDeclStmt())
     PrintRawDeclStmt(DS);
   else
     PrintExpr(Node->getCond());
-  OS << ")\n";
+  OS << ")" << NewlineSymbol;
   PrintStmt(Node->getBody());
 }
 
 void StmtPrinter::VisitDoStmt(DoStmt *Node) {
   Indent() << "do ";
   if (auto *CS = dyn_cast<CompoundStmt>(Node->getBody())) {
     PrintRawCompoundStmt(CS);
     OS << " ";
   } else {
-    OS << "\n";
+    OS << NewlineSymbol;
     PrintStmt(Node->getBody());
     Indent();
   }
 
   OS << "while (";
   PrintExpr(Node->getCond());
-  OS << ");\n";
+  OS << ");" << NewlineSymbol;
 }
 
 void StmtPrinter::VisitForStmt(ForStmt *Node) {
   Indent() << "for (";
   if (Node->getInit()) {
     if (auto *DS = dyn_cast<DeclStmt>(Node->getInit()))
       PrintRawDeclStmt(DS);
     else
       PrintExpr(cast<Expr>(Node->getInit()));
   }
   OS << ";";
   if (Node->getCond()) {
     OS << " ";
     PrintExpr(Node->getCond());
   }
   OS << ";";
   if (Node->getInc()) {
     OS << " ";
     PrintExpr(Node->getInc());
   }
   OS << ") ";
 
   if (auto *CS = dyn_cast<CompoundStmt>(Node->getBody())) {
     PrintRawCompoundStmt(CS);
-    OS << "\n";
+    OS << NewlineSymbol;
   } else {
-    OS << "\n";
+    OS << NewlineSymbol;
     PrintStmt(Node->getBody());
   }
 }
 
 void StmtPrinter::VisitObjCForCollectionStmt(ObjCForCollectionStmt *Node) {
   Indent() << "for (";
   if (auto *DS = dyn_cast<DeclStmt>(Node->getElement()))
     PrintRawDeclStmt(DS);
   else
     PrintExpr(cast<Expr>(Node->getElement()));
   OS << " in ";
   PrintExpr(Node->getCollection());
   OS << ") ";
 
   if (auto *CS = dyn_cast<CompoundStmt>(Node->getBody())) {
     PrintRawCompoundStmt(CS);
-    OS << "\n";
+    OS << NewlineSymbol;
   } else {
-    OS << "\n";
+    OS << NewlineSymbol;
     PrintStmt(Node->getBody());
   }
 }
 
 void StmtPrinter::VisitCXXForRangeStmt(CXXForRangeStmt *Node) {
   Indent() << "for (";
   PrintingPolicy SubPolicy(Policy);
   SubPolicy.SuppressInitializers = true;
   Node->getLoopVariable()->print(OS, SubPolicy, IndentLevel);
   OS << " : ";
   PrintExpr(Node->getRangeInit());
-  OS << ") {\n";
+  OS << ") {" << NewlineSymbol;
   PrintStmt(Node->getBody());
   Indent() << "}";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitMSDependentExistsStmt(MSDependentExistsStmt *Node) {
   Indent();
   if (Node->isIfExists())
     OS << "__if_exists (";
   else
     OS << "__if_not_exists (";
 
   if (NestedNameSpecifier *Qualifier
         = Node->getQualifierLoc().getNestedNameSpecifier())
     Qualifier->print(OS, Policy);
 
   OS << Node->getNameInfo() << ") ";
 
   PrintRawCompoundStmt(Node->getSubStmt());
 }
 
 void StmtPrinter::VisitGotoStmt(GotoStmt *Node) {
   Indent() << "goto " << Node->getLabel()->getName() << ";";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitIndirectGotoStmt(IndirectGotoStmt *Node) {
   Indent() << "goto *";
   PrintExpr(Node->getTarget());
   OS << ";";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitContinueStmt(ContinueStmt *Node) {
   Indent() << "continue;";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitBreakStmt(BreakStmt *Node) {
   Indent() << "break;";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitReturnStmt(ReturnStmt *Node) {
   Indent() << "return";
   if (Node->getRetValue()) {
     OS << " ";
     PrintExpr(Node->getRetValue());
   }
   OS << ";";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitGCCAsmStmt(GCCAsmStmt *Node) {
   Indent() << "asm ";
 
   if (Node->isVolatile())
     OS << "volatile ";
 
void StmtPrinter::VisitGCCAsmStmt(GCCAsmStmt *Node) {
   for (unsigned i = 0, e = Node->getNumClobbers(); i != e; ++i) {
     if (i != 0)
       OS << ", ";
 
     VisitStringLiteral(Node->getClobberStringLiteral(i));
   }
 
   OS << ");";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitMSAsmStmt(MSAsmStmt *Node) {
   // FIXME: Implement MS style inline asm statement printer.
   Indent() << "__asm ";
   if (Node->hasBraces())
-    OS << "{\n";
-  OS << Node->getAsmString() << "\n";
+    OS << "{" << NewlineSymbol;
+  OS << Node->getAsmString() << NewlineSymbol;
   if (Node->hasBraces())
-    Indent() << "}\n";
+    Indent() << "}" << NewlineSymbol;
 }
 
 void StmtPrinter::VisitCapturedStmt(CapturedStmt *Node) {
   PrintStmt(Node->getCapturedDecl()->getBody());
 }
 
 void StmtPrinter::VisitObjCAtTryStmt(ObjCAtTryStmt *Node) {
   Indent() << "@try";
   if (auto *TS = dyn_cast<CompoundStmt>(Node->getTryBody())) {
     PrintRawCompoundStmt(TS);
-    OS << "\n";
+    OS << NewlineSymbol;
   }
 
   for (unsigned I = 0, N = Node->getNumCatchStmts(); I != N; ++I) {
     ObjCAtCatchStmt *catchStmt = Node->getCatchStmt(I);
     Indent() << "@catch(";
     if (catchStmt->getCatchParamDecl()) {
       if (Decl *DS = catchStmt->getCatchParamDecl())
         PrintRawDecl(DS);
     }
     OS << ")";
     if (auto *CS = dyn_cast<CompoundStmt>(catchStmt->getCatchBody())) {
       PrintRawCompoundStmt(CS);
-      OS << "\n";
+      OS << NewlineSymbol;
     }
   }
 
   if (auto *FS = static_cast<ObjCAtFinallyStmt *>(Node->getFinallyStmt())) {
     Indent() << "@finally";
     PrintRawCompoundStmt(dyn_cast<CompoundStmt>(FS->getFinallyBody()));
-    OS << "\n";
+    OS << NewlineSymbol;
   }
 }
 
 void StmtPrinter::VisitObjCAtFinallyStmt(ObjCAtFinallyStmt *Node) {
 }
 
 void StmtPrinter::VisitObjCAtCatchStmt (ObjCAtCatchStmt *Node) {
-  Indent() << "@catch (...) { /* todo */ } \n";
+  Indent() << "@catch (...) { /* todo */ } " << NewlineSymbol;
 }
 
 void StmtPrinter::VisitObjCAtThrowStmt(ObjCAtThrowStmt *Node) {
   Indent() << "@throw";
   if (Node->getThrowExpr()) {
     OS << " ";
     PrintExpr(Node->getThrowExpr());
   }
-  OS << ";\n";
+  OS << ";" << NewlineSymbol;
 }
 
 void StmtPrinter::VisitObjCAvailabilityCheckExpr(
     ObjCAvailabilityCheckExpr *Node) {
   OS << "@available(...)";
 }
 
 void StmtPrinter::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *Node) {
   Indent() << "@synchronized (";
   PrintExpr(Node->getSynchExpr());
   OS << ")";
   PrintRawCompoundStmt(Node->getSynchBody());
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *Node) {
   Indent() << "@autoreleasepool";
   PrintRawCompoundStmt(dyn_cast<CompoundStmt>(Node->getSubStmt()));
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::PrintRawCXXCatchStmt(CXXCatchStmt *Node) {
   OS << "catch (";
   if (Decl *ExDecl = Node->getExceptionDecl())
     PrintRawDecl(ExDecl);
   else
     OS << "...";
   OS << ") ";
   PrintRawCompoundStmt(cast<CompoundStmt>(Node->getHandlerBlock()));
 }
 
 void StmtPrinter::VisitCXXCatchStmt(CXXCatchStmt *Node) {
   Indent();
   PrintRawCXXCatchStmt(Node);
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitCXXTryStmt(CXXTryStmt *Node) {
   Indent() << "try ";
   PrintRawCompoundStmt(Node->getTryBlock());
   for (unsigned i = 0, e = Node->getNumHandlers(); i < e; ++i) {
     OS << " ";
     PrintRawCXXCatchStmt(Node->getHandler(i));
   }
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitSEHTryStmt(SEHTryStmt *Node) {
   Indent() << (Node->getIsCXXTry() ? "try " : "__try ");
   PrintRawCompoundStmt(Node->getTryBlock());
   SEHExceptStmt *E = Node->getExceptHandler();
   SEHFinallyStmt *F = Node->getFinallyHandler();
   if(E)
     PrintRawSEHExceptHandler(E);
   else {
     assert(F && "Must have a finally block...");
     PrintRawSEHFinallyStmt(F);
   }
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::PrintRawSEHFinallyStmt(SEHFinallyStmt *Node) {
   OS << "__finally ";
   PrintRawCompoundStmt(Node->getBlock());
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::PrintRawSEHExceptHandler(SEHExceptStmt *Node) {
   OS << "__except (";
   VisitExpr(Node->getFilterExpr());
-  OS << ")\n";
+  OS << ")" << NewlineSymbol;
   PrintRawCompoundStmt(Node->getBlock());
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitSEHExceptStmt(SEHExceptStmt *Node) {
   Indent();
   PrintRawSEHExceptHandler(Node);
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitSEHFinallyStmt(SEHFinallyStmt *Node) {
   Indent();
   PrintRawSEHFinallyStmt(Node);
-  OS << "\n";
+  OS << NewlineSymbol;
 }
 
 void StmtPrinter::VisitSEHLeaveStmt(SEHLeaveStmt *Node) {
   Indent() << "__leave;";
-  if (Policy.IncludeNewlines) OS << "\n";
+  if (Policy.IncludeNewlines) OS << NewlineSymbol;
 }
 
 //===----------------------------------------------------------------------===//
 //  OpenMP clauses printing methods
 //===----------------------------------------------------------------------===//
 
 namespace {
 
void StmtPrinter::PrintOMPExecutableDirective(OMPExecutableDirective *S,
                                               bool ForceNoStmt) {
   OMPClausePrinter Printer(OS, Policy);
   ArrayRef<OMPClause *> Clauses = S->clauses();
   for (auto *Clause : Clauses)
     if (Clause && !Clause->isImplicit()) {
       OS << ' ';
       Printer.Visit(Clause);
     }
-  OS << "\n";
+  OS << NewlineSymbol;
   if (!ForceNoStmt && S->hasAssociatedStmt())
     PrintStmt(S->getInnermostCapturedStmt()->getCapturedStmt());
 }
 
 void StmtPrinter::VisitOMPParallelDirective(OMPParallelDirective *Node) {
   Indent() << "#pragma omp parallel";
   PrintOMPExecutableDirective(Node);
 }

 //===----------------------------------------------------------------------===//
 
 void Stmt::dumpPretty(const ASTContext &Context) const {
   printPretty(llvm::errs(), nullptr, PrintingPolicy(Context.getLangOpts()));
 }
 
 void Stmt::printPretty(raw_ostream &OS, PrinterHelper *Helper,
                        const PrintingPolicy &Policy, unsigned Indentation,
+                       StringRef NewlineSymbol,
                        const ASTContext *Context) const {
-  StmtPrinter P(OS, Helper, Policy, Indentation, Context);
+  StmtPrinter P(OS, Helper, Policy, Indentation, NewlineSymbol, Context);
   P.Visit(const_cast<Stmt*>(this));
 }
 
 //===----------------------------------------------------------------------===//
 // PrinterHelper
 //===----------------------------------------------------------------------===//
 
 // Implement virtual destructor.
 PrinterHelper::~PrinterHelper() = default;