[NFC][MLIR][TableGen] Adopt NamespaceEmitter more widely (#163289)

Adopt NamespaceEmitter more widely in MLIR TableGen.

llvm/include/llvm/TableGen/CodeGenHelpers.h

@@ -50,19 +50,21 @@ private:
 };
 
 // Simple RAII helper for emitting namespace scope. Name can be a single
-// namespace (empty for anonymous namespace) or nested namespace.
+// namespace or nested namespace. If the name is empty, will not generate any
+// namespace scope.
 class NamespaceEmitter {
 public:
-  NamespaceEmitter(raw_ostream &OS, StringRef Name)
-      : Name(trim(Name).str()), OS(OS) {
-    OS << "namespace " << this->Name << " {\n";
+  NamespaceEmitter(raw_ostream &OS, StringRef NameUntrimmed)
+      : Name(trim(NameUntrimmed).str()), OS(OS) {
+    if (!Name.empty())
+      OS << "namespace " << Name << " {\n";
   }
 
   ~NamespaceEmitter() { close(); }
 
   // Explicit function to close the namespace scopes.
   void close() {
-    if (!Closed)
+    if (!Closed && !Name.empty())
       OS << "} // namespace " << Name << "\n";
     Closed = true;
   }

mlir/test/mlir-tblgen/cpp-class-comments.td

@@ -96,17 +96,14 @@ def EncodingTrait : AttrInterface<"EncodingTrait"> {
   }];
   let methods = [
   ];
-// ATTR-INTERFACE: namespace mlir
-// ATTR-INTERFACE-NEXT: namespace a
-// ATTR-INTERFACE-NEXT: namespace traits
+// ATTR-INTERFACE: namespace mlir::a::traits {
 // ATTR-INTERFACE-NEXT: /// Common trait for all layouts.
 // ATTR-INTERFACE-NEXT: class EncodingTrait;
 }
 
 def SimpleEncodingTrait : AttrInterface<"SimpleEncodingTrait"> {
   let cppNamespace = "a::traits";
-// ATTR-INTERFACE: namespace a {
-// ATTR-INTERFACE-NEXT: namespace traits {
+// ATTR-INTERFACE: namespace a::traits {
 // ATTR-INTERFACE-NEXT: class SimpleEncodingTrait;
 }
 
@@ -116,8 +113,7 @@ def SimpleOpInterface : OpInterface<"SimpleOpInterface"> {
 
     Simple Op Interface description
     }];
-// OP-INTERFACE: namespace a {
-// OP-INTERFACE-NEXT: namespace traits {
+// OP-INTERFACE: namespace a::traits {
 // OP-INTERFACE-NEXT: /// Simple Op Interface description
 // OP-INTERFACE-NEXT: class SimpleOpInterface;
 }

mlir/tools/mlir-tblgen/EnumsGen.cpp

@@ -20,6 +20,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/TableGen/CodeGenHelpers.h"
 #include "llvm/TableGen/Error.h"
 #include "llvm/TableGen/Record.h"
 #include "llvm/TableGen/TableGenBackend.h"
@@ -701,11 +702,7 @@ static void emitEnumDecl(const Record &enumDef, raw_ostream &os) {
   StringRef underlyingToSymFnName = enumInfo.getUnderlyingToSymbolFnName();
   auto enumerants = enumInfo.getAllCases();
 
-  SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(cppNamespace, namespaces, "::");
-
-  for (auto ns : namespaces)
-    os << "namespace " << ns << " {\n";
+  llvm::NamespaceEmitter ns(os, cppNamespace);
 
   // Emit the enum class definition
   emitEnumClass(enumDef, enumName, underlyingType, description, enumerants, os);
@@ -766,8 +763,7 @@ public:
     os << formatv(attrClassDecl, enumName, attrClassName, baseAttrClassName);
   }
 
-  for (auto ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
+  ns.close();
 
   // Generate a generic parser and printer for the enum.
   std::string qualName =
@@ -790,13 +786,8 @@ static bool emitEnumDecls(const RecordKeeper &records, raw_ostream &os) {
 
 static void emitEnumDef(const Record &enumDef, raw_ostream &os) {
   EnumInfo enumInfo(enumDef);
-  StringRef cppNamespace = enumInfo.getCppNamespace();
 
-  SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(cppNamespace, namespaces, "::");
-
-  for (auto ns : namespaces)
-    os << "namespace " << ns << " {\n";
+  llvm::NamespaceEmitter ns(os, enumInfo.getCppNamespace());
 
   if (enumInfo.isBitEnum()) {
     emitSymToStrFnForBitEnum(enumDef, os);
@@ -810,10 +801,6 @@ static void emitEnumDef(const Record &enumDef, raw_ostream &os) {
 
   if (enumInfo.genSpecializedAttr())
     emitSpecializedAttrDef(enumDef, os);
-
-  for (auto ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
-  os << "\n";
 }
 
 static bool emitEnumDefs(const RecordKeeper &records, raw_ostream &os) {

mlir/tools/mlir-tblgen/OpInterfacesGen.cpp

@@ -19,6 +19,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/TableGen/CodeGenHelpers.h"
 #include "llvm/TableGen/Error.h"
 #include "llvm/TableGen/Record.h"
 #include "llvm/TableGen/TableGenBackend.h"
@@ -342,11 +343,7 @@ void InterfaceGenerator::emitModelDecl(const Interface &interface) {
 }
 
 void InterfaceGenerator::emitModelMethodsDef(const Interface &interface) {
-  llvm::SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(interface.getCppNamespace(), namespaces, "::");
-  for (StringRef ns : namespaces)
-    os << "namespace " << ns << " {\n";
-
+  llvm::NamespaceEmitter ns(os, interface.getCppNamespace());
   for (auto &method : interface.getMethods()) {
     os << "template<typename " << valueTemplate << ">\n";
     emitCPPType(method.getReturnType(), os);
@@ -442,18 +439,11 @@ void InterfaceGenerator::emitModelMethodsDef(const Interface &interface) {
                         method.isStatic() ? &ctx : &nonStaticMethodFmt);
     os << "\n}\n";
   }
-
-  for (StringRef ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
 }
 
 void InterfaceGenerator::emitInterfaceTraitDecl(const Interface &interface) {
-  llvm::SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(interface.getCppNamespace(), namespaces, "::");
-  for (StringRef ns : namespaces)
-    os << "namespace " << ns << " {\n";
-
-  os << "namespace detail {\n";
+  auto cppNamespace = (interface.getCppNamespace() + "::detail").str();
+  llvm::NamespaceEmitter ns(os, cppNamespace);
 
   StringRef interfaceName = interface.getName();
   auto interfaceTraitsName = (interfaceName + "InterfaceTraits").str();
@@ -504,10 +494,6 @@ void InterfaceGenerator::emitInterfaceTraitDecl(const Interface &interface) {
     os << tblgen::tgfmt(*extraTraitDecls, &traitMethodFmt) << "\n";
 
   os << "  };\n";
-  os << "}// namespace detail\n";
-
-  for (StringRef ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
 }
 
 static void emitInterfaceDeclMethods(const Interface &interface,
@@ -533,10 +519,7 @@ static void emitInterfaceDeclMethods(const Interface &interface,
 }
 
 void InterfaceGenerator::forwardDeclareInterface(const Interface &interface) {
-  llvm::SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(interface.getCppNamespace(), namespaces, "::");
-  for (StringRef ns : namespaces)
-    os << "namespace " << ns << " {\n";
+  llvm::NamespaceEmitter ns(os, interface.getCppNamespace());
 
   // Emit a forward declaration of the interface class so that it becomes usable
   // in the signature of its methods.
@@ -545,16 +528,10 @@ void InterfaceGenerator::forwardDeclareInterface(const Interface &interface) {
 
   StringRef interfaceName = interface.getName();
   os << "class " << interfaceName << ";\n";
-
-  for (StringRef ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
 }
 
 void InterfaceGenerator::emitInterfaceDecl(const Interface &interface) {
-  llvm::SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(interface.getCppNamespace(), namespaces, "::");
-  for (StringRef ns : namespaces)
-    os << "namespace " << ns << " {\n";
+  llvm::NamespaceEmitter ns(os, interface.getCppNamespace());
 
   StringRef interfaceName = interface.getName();
   auto interfaceTraitsName = (interfaceName + "InterfaceTraits").str();
@@ -631,9 +608,6 @@ void InterfaceGenerator::emitInterfaceDecl(const Interface &interface) {
   }
 
   os << "};\n";
-
-  for (StringRef ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
 }
 
 bool InterfaceGenerator::emitInterfaceDecls() {

mlir/tools/mlir-tblgen/SPIRVUtilsGen.cpp

@@ -259,8 +259,8 @@ static void emitInterfaceDecl(const Availability &availability,
   std::string interfaceTraitsName =
       std::string(formatv("{0}Traits", interfaceName));
 
-  StringRef cppNamespace = availability.getInterfaceClassNamespace();
-  llvm::NamespaceEmitter nsEmitter(os, cppNamespace);
+  llvm::NamespaceEmitter nsEmitter(os,
+                                   availability.getInterfaceClassNamespace());
   os << "class " << interfaceName << ";\n\n";
 
   // Emit the traits struct containing the concept and model declarations.
@@ -418,15 +418,9 @@ static void emitAvailabilityQueryForBitEnum(const Record &enumDef,
 static void emitEnumDecl(const Record &enumDef, raw_ostream &os) {
   EnumInfo enumInfo(enumDef);
   StringRef enumName = enumInfo.getEnumClassName();
-  StringRef cppNamespace = enumInfo.getCppNamespace();
   auto enumerants = enumInfo.getAllCases();
 
-  llvm::SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(cppNamespace, namespaces, "::");
-
-  for (auto ns : namespaces)
-    os << "namespace " << ns << " {\n";
-
+  llvm::NamespaceEmitter ns(os, enumInfo.getCppNamespace());
   llvm::StringSet<> handledClasses;
 
   // Place all availability specifications to their corresponding
@@ -441,9 +435,6 @@ static void emitEnumDecl(const Record &enumDef, raw_ostream &os) {
                     enumName);
       handledClasses.insert(className);
     }
-
-  for (auto ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
 }
 
 static bool emitEnumDecls(const RecordKeeper &records, raw_ostream &os) {
@@ -459,31 +450,19 @@ static bool emitEnumDecls(const RecordKeeper &records, raw_ostream &os) {
 
 static void emitEnumDef(const Record &enumDef, raw_ostream &os) {
   EnumInfo enumInfo(enumDef);
-  StringRef cppNamespace = enumInfo.getCppNamespace();
+  llvm::NamespaceEmitter ns(os, enumInfo.getCppNamespace());
 
-  llvm::SmallVector<StringRef, 2> namespaces;
-  llvm::SplitString(cppNamespace, namespaces, "::");
-
-  for (auto ns : namespaces)
-    os << "namespace " << ns << " {\n";
-
-  if (enumInfo.isBitEnum()) {
+  if (enumInfo.isBitEnum())
     emitAvailabilityQueryForBitEnum(enumDef, os);
-  } else {
+  else
     emitAvailabilityQueryForIntEnum(enumDef, os);
-  }
-
-  for (auto ns : llvm::reverse(namespaces))
-    os << "} // namespace " << ns << "\n";
-  os << "\n";
 }
 
 static bool emitEnumDefs(const RecordKeeper &records, raw_ostream &os) {
   llvm::emitSourceFileHeader("SPIR-V Enum Availability Definitions", os,
                              records);
 
-  auto defs = records.getAllDerivedDefinitions("EnumInfo");
-  for (const auto *def : defs)
+  for (const Record *def : records.getAllDerivedDefinitions("EnumInfo"))
     emitEnumDef(*def, os);
 
   return false;