Remove line and file from DINamespace.

Fixes the issue highlighted in
http://lists.llvm.org/pipermail/cfe-dev/2014-June/037500.html.

The DW_AT_decl_file and DW_AT_decl_line attributes on namespaces can
prevent LLVM from uniquing types that are in the same namespace. They
also don't carry any meaningful information.

rdar://problem/17484998
Differential Revision: https://reviews.llvm.org/D32648

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301706 91177308-0d34-0410-b5e6-96231b3b80d8

Author: adrian-prantl

include/llvm/IR/DIBuilder.h

@@ -632,11 +632,9 @@ namespace llvm {
     /// parent scope.
     /// \param Scope       Namespace scope
     /// \param Name        Name of this namespace
-    /// \param File        Source file
-    /// \param LineNo      Line number
     /// \param ExportSymbols True for C++ inline namespaces.
-    DINamespace *createNameSpace(DIScope *Scope, StringRef Name, DIFile *File,
-                                 unsigned LineNo, bool ExportSymbols);
+    DINamespace *createNameSpace(DIScope *Scope, StringRef Name,
+                                 bool ExportSymbols);
 
     /// This creates new descriptor for a module with the specified
     /// parent scope.

include/llvm/IR/DebugInfoMetadata.h

@@ -1853,45 +1853,40 @@ class DINamespace : public DIScope {
   friend class LLVMContextImpl;
   friend class MDNode;
 
-  unsigned Line;
   unsigned ExportSymbols : 1;
 
-  DINamespace(LLVMContext &Context, StorageType Storage, unsigned Line,
-              bool ExportSymbols, ArrayRef<Metadata *> Ops)
+  DINamespace(LLVMContext &Context, StorageType Storage, bool ExportSymbols,
+              ArrayRef<Metadata *> Ops)
       : DIScope(Context, DINamespaceKind, Storage, dwarf::DW_TAG_namespace,
                 Ops),
-        Line(Line), ExportSymbols(ExportSymbols) {}
+        ExportSymbols(ExportSymbols) {}
   ~DINamespace() = default;
 
   static DINamespace *getImpl(LLVMContext &Context, DIScope *Scope,
-                              DIFile *File, StringRef Name, unsigned Line,
-                              bool ExportSymbols, StorageType Storage,
-                              bool ShouldCreate = true) {
-    return getImpl(Context, Scope, File, getCanonicalMDString(Context, Name),
-                   Line, ExportSymbols, Storage, ShouldCreate);
+                              StringRef Name, bool ExportSymbols,
+                              StorageType Storage, bool ShouldCreate = true) {
+    return getImpl(Context, Scope, getCanonicalMDString(Context, Name),
+                   ExportSymbols, Storage, ShouldCreate);
   }
   static DINamespace *getImpl(LLVMContext &Context, Metadata *Scope,
-                              Metadata *File, MDString *Name, unsigned Line,
-                              bool ExportSymbols, StorageType Storage,
-                              bool ShouldCreate = true);
+                              MDString *Name, bool ExportSymbols,
+                              StorageType Storage, bool ShouldCreate = true);
 
   TempDINamespace cloneImpl() const {
-    return getTemporary(getContext(), getScope(), getFile(), getName(),
-                        getLine(), getExportSymbols());
+    return getTemporary(getContext(), getScope(), getName(),
+                        getExportSymbols());
   }
 
 public:
-  DEFINE_MDNODE_GET(DINamespace, (DIScope * Scope, DIFile *File, StringRef Name,
-                                  unsigned Line, bool ExportSymbols),
-                    (Scope, File, Name, Line, ExportSymbols))
   DEFINE_MDNODE_GET(DINamespace,
-                    (Metadata * Scope, Metadata *File, MDString *Name,
-                     unsigned Line, bool ExportSymbols),
-                    (Scope, File, Name, Line, ExportSymbols))
+                    (DIScope *Scope, StringRef Name, bool ExportSymbols),
+                    (Scope, Name, ExportSymbols))
+  DEFINE_MDNODE_GET(DINamespace,
+                    (Metadata *Scope, MDString *Name, bool ExportSymbols),
+                    (Scope, Name, ExportSymbols))
 
   TempDINamespace clone() const { return cloneImpl(); }
 
-  unsigned getLine() const { return Line; }
   bool getExportSymbols() const { return ExportSymbols; }
   DIScope *getScope() const { return cast_or_null<DIScope>(getRawScope()); }
   StringRef getName() const { return getStringOperand(2); }

lib/AsmParser/LLParser.cpp

@@ -4150,15 +4150,13 @@ bool LLParser::ParseDILexicalBlockFile(MDNode *&Result, bool IsDistinct) {
 bool LLParser::ParseDINamespace(MDNode *&Result, bool IsDistinct) {
 #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
   REQUIRED(scope, MDField, );                                                  \
-  OPTIONAL(file, MDField, );                                                   \
   OPTIONAL(name, MDStringField, );                                             \
-  OPTIONAL(line, LineField, );                                                 \
   OPTIONAL(exportSymbols, MDBoolField, );
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
 
   Result = GET_OR_DISTINCT(DINamespace,
-  (Context, scope.Val, file.Val, name.Val, line.Val, exportSymbols.Val));
+                           (Context, scope.Val, name.Val, exportSymbols.Val));
   return false;
 }
 

lib/Bitcode/Reader/MetadataLoader.cpp

@@ -1383,16 +1383,20 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     break;
   }
   case bitc::METADATA_NAMESPACE: {
-    if (Record.size() != 5)
+    // Newer versions of DINamespace dropped file and line.
+    MDString *Name;
+    if (Record.size() == 3)
+      Name = getMDString(Record[2]);
+    else if (Record.size() == 5)
+      Name = getMDString(Record[3]);
+    else
       return error("Invalid record");
 
     IsDistinct = Record[0] & 1;
     bool ExportSymbols = Record[0] & 2;
     MetadataList.assignValue(
         GET_OR_DISTINCT(DINamespace,
-                        (Context, getMDOrNull(Record[1]),
-                         getMDOrNull(Record[2]), getMDString(Record[3]),
-                         Record[4], ExportSymbols)),
+                        (Context, getMDOrNull(Record[1]), Name, ExportSymbols)),
         NextMetadataNo);
     NextMetadataNo++;
     break;

lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -1646,9 +1646,7 @@ void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
                                            unsigned Abbrev) {
   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
-  Record.push_back(VE.getMetadataOrNullID(N->getFile()));
   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
-  Record.push_back(N->getLine());
 
   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
   Record.clear();

lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -375,10 +375,6 @@ void DwarfUnit::addSourceLine(DIE &Die, const DIObjCProperty *Ty) {
   addSourceLine(Die, Ty->getLine(), Ty->getFilename(), Ty->getDirectory());
 }
 
-void DwarfUnit::addSourceLine(DIE &Die, const DINamespace *NS) {
-  addSourceLine(Die, NS->getLine(), NS->getFilename(), NS->getDirectory());
-}
-
 /* Byref variables, in Blocks, are declared by the programmer as "SomeType
    VarName;", but the compiler creates a __Block_byref_x_VarName struct, and
    gives the variable VarName either the struct, or a pointer to the struct, as
@@ -1085,7 +1081,6 @@ DIE *DwarfUnit::getOrCreateNameSpace(const DINamespace *NS) {
     Name = "(anonymous namespace)";
   DD->addAccelNamespace(Name, NDie);
   addGlobalName(Name, NDie, NS->getScope());
-  addSourceLine(NDie, NS);
   if (NS->getExportSymbols())
     addFlag(NDie, dwarf::DW_AT_export_symbols);
   return &NDie;

lib/CodeGen/AsmPrinter/DwarfUnit.h

@@ -210,7 +210,6 @@ class RangeSpanList {
   void addSourceLine(DIE &Die, const DIGlobalVariable *G);
   void addSourceLine(DIE &Die, const DISubprogram *SP);
   void addSourceLine(DIE &Die, const DIType *Ty);
-  void addSourceLine(DIE &Die, const DINamespace *NS);
   void addSourceLine(DIE &Die, const DIObjCProperty *Ty);
 
   /// Add constant value entry in variable DIE.

lib/IR/AsmWriter.cpp

@@ -1756,8 +1756,6 @@ static void writeDINamespace(raw_ostream &Out, const DINamespace *N,
   MDFieldPrinter Printer(Out, TypePrinter, Machine, Context);
   Printer.printString("name", N->getName());
   Printer.printMetadata("scope", N->getRawScope(), /* ShouldSkipNull */ false);
-  Printer.printMetadata("file", N->getRawFile());
-  Printer.printInt("line", N->getLine());
   Printer.printBool("exportSymbols", N->getExportSymbols(), false);
   Out << ")";
 }

lib/IR/DIBuilder.cpp

@@ -728,10 +728,15 @@ DISubprogram *DIBuilder::createMethod(
 }
 
 DINamespace *DIBuilder::createNameSpace(DIScope *Scope, StringRef Name,
-                                        DIFile *File, unsigned LineNo,
                                         bool ExportSymbols) {
-  return DINamespace::get(VMContext, getNonCompileUnitScope(Scope), File, Name,
-                          LineNo, ExportSymbols);
+
+  // It is okay to *not* make anonymous top-level namespaces distinct, because
+  // all nodes that have an anonymous namespace as their parent scope are
+  // guaranteed to be unique and/or are linked to their containing
+  // DICompileUnit. This decision is an explicit tradeoff of link time versus
+  // memory usage versus code simplicity and may get revisited in the future.
+  return DINamespace::get(VMContext, getNonCompileUnitScope(Scope), Name,
+                          ExportSymbols);
 }
 
 DIModule *DIBuilder::createModule(DIScope *Scope, StringRef Name,

lib/IR/DebugInfoMetadata.cpp

@@ -507,13 +507,13 @@ DILexicalBlockFile *DILexicalBlockFile::getImpl(LLVMContext &Context,
 }
 
 DINamespace *DINamespace::getImpl(LLVMContext &Context, Metadata *Scope,
-                                  Metadata *File, MDString *Name, unsigned Line,
-                                  bool ExportSymbols, StorageType Storage,
-                                  bool ShouldCreate) {
+                                  MDString *Name, bool ExportSymbols,
+                                  StorageType Storage, bool ShouldCreate) {
   assert(isCanonical(Name) && "Expected canonical MDString");
-  DEFINE_GETIMPL_LOOKUP(DINamespace, (Scope, File, Name, Line, ExportSymbols));
-  Metadata *Ops[] = {File, Scope, Name};
-  DEFINE_GETIMPL_STORE(DINamespace, (Line, ExportSymbols), Ops);
+  DEFINE_GETIMPL_LOOKUP(DINamespace, (Scope, Name, ExportSymbols));
+  // The nullptr is for DIScope's File operand. This should be refactored.
+  Metadata *Ops[] = {nullptr, Scope, Name};
+  DEFINE_GETIMPL_STORE(DINamespace, (ExportSymbols), Ops);
 }
 
 DIModule *DIModule::getImpl(LLVMContext &Context, Metadata *Scope,