[Serialization] Use the module interface as the name of the file

...rather than the buffer, for a compiled module that came from a
module interface.

This was already happening at a higher level
(ModuleDecl::getModuleFilename) so pushing it down to the low-level
ModuleFile::getModuleFilename doesn't really change things much. The
important fix that goes with this is that SerializedASTFile no longer
leaks this name by storing it outside of ModuleFile.

https://bugs.swift.org/browse/SR-11365

Author: jrose-apple

include/swift/AST/Module.h

@@ -872,10 +872,6 @@ class FileUnit : public DeclContext {
     return getParentModule()->getName().str();
   }
 
-  /// If this is a module imported from a parseable interface, return the path
-  /// to the interface file, otherwise an empty StringRef.
-  virtual StringRef getParseableInterface() const { return {}; }
-
   /// Traverse the decls within this file.
   ///
   /// \returns true if traversal was aborted, false if it completed

include/swift/Serialization/ModuleFile.h

@@ -78,6 +78,11 @@ class ModuleFile
   /// The target the module was built for.
   StringRef TargetTriple;
 
+  /// The name of the module interface this module was compiled from.
+  ///
+  /// Empty if this module didn't come from an interface file.
+  StringRef ModuleInterfacePath;
+
   /// The Swift compatibility version in use when this module was built.
   version::Version CompatibilityVersion;
 
@@ -762,6 +767,8 @@ class ModuleFile
   void getDisplayDecls(SmallVectorImpl<Decl*> &results);
 
   StringRef getModuleFilename() const {
+    if (!ModuleInterfacePath.empty())
+      return ModuleInterfacePath;
     // FIXME: This seems fragile, maybe store the filename separately ?
     return ModuleInputBuffer->getBufferIdentifier();
   }

include/swift/Serialization/SerializedModuleLoader.h

@@ -251,10 +251,6 @@ class SerializedASTFile final : public LoadedFile {
 
   ModuleFile &File;
 
-  /// The parseable interface this module was generated from if any.
-  /// Used for debug info.
-  std::string ParseableInterface;
-
   bool IsSIB;
 
   ~SerializedASTFile() = default;
@@ -351,13 +347,6 @@ class SerializedASTFile final : public LoadedFile {
 
   virtual const clang::Module *getUnderlyingClangModule() const override;
 
-  /// If this is a module imported from a parseable interface, return the path
-  /// to the interface file, otherwise an empty StringRef.
-  virtual StringRef getParseableInterface() const override {
-    return ParseableInterface;
-  }
-  void setParseableInterface(StringRef PI) { ParseableInterface = PI; }
-  
   virtual bool getAllGenericSignatures(
                    SmallVectorImpl<GenericSignature*> &genericSignatures)
                 override;

include/swift/Serialization/Validation.h

@@ -92,7 +92,6 @@ struct ValidationInfo {
 class ExtendedValidationInfo {
   SmallVector<StringRef, 4> ExtraClangImporterOpts;
   StringRef SDKPath;
-  StringRef ParseableInterface;
   struct {
     unsigned ArePrivateImportsEnabled : 1;
     unsigned IsSIB : 1;
@@ -114,8 +113,6 @@ class ExtendedValidationInfo {
   void addExtraClangImporterOption(StringRef option) {
     ExtraClangImporterOpts.push_back(option);
   }
-  StringRef getParseableInterface() const { return ParseableInterface; }
-  void setParseableInterface(StringRef PI) { ParseableInterface = PI; }
 
   bool isSIB() const { return Bits.IsSIB; }
   void setIsSIB(bool val) {

lib/AST/Module.cpp

@@ -1249,10 +1249,6 @@ StringRef ModuleDecl::getModuleFilename() const {
   // per-file names. Modules can consist of more than one file.
   StringRef Result;
   for (auto F : getFiles()) {
-    Result = F->getParseableInterface();
-    if (!Result.empty())
-      return Result;
-
     if (auto SF = dyn_cast<SourceFile>(F)) {
       if (!Result.empty())
         return StringRef();

lib/Serialization/ModuleFile.cpp

@@ -1352,8 +1352,7 @@ ModuleFile::ModuleFile(
           break;
         }
         case input_block::PARSEABLE_INTERFACE_PATH: {
-          if (extInfo)
-            extInfo->setParseableInterface(blobData);
+          ModuleInterfacePath = blobData;
           break;
         }
         default:

lib/Serialization/SerializedModuleLoader.cpp

@@ -548,7 +548,6 @@ FileUnit *SerializedModuleLoaderBase::loadAST(
     // We've loaded the file. Now try to bring it into the AST.
     auto fileUnit = new (Ctx) SerializedASTFile(M, *loadedModuleFile,
                                                 extendedInfo.isSIB());
-    fileUnit->setParseableInterface(extendedInfo.getParseableInterface());
     M.addFile(*fileUnit);
     if (extendedInfo.isTestable())
       M.setTestingEnabled();