[AST] Do not copy SearchPathOptions in updateNonUserModule

`updateNonUserModule` was accidentally copying `SearchPathOptions`. Take
a reference to it instead. Also, since `addFile` is actually called many
times (once for every submodule, of which there are many), change
`isNonUserModule` to a request so that it's only calculated when needed.

Resolves rdar://107155587.

Author: bnbarham

include/swift/AST/Decl.h

@@ -630,7 +630,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     HasAnyUnavailableValues : 1
   );
 
-  SWIFT_INLINE_BITFIELD(ModuleDecl, TypeDecl, 1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1,
+  SWIFT_INLINE_BITFIELD(ModuleDecl, TypeDecl, 1+1+1+1+1+1+1+1+1+1+1+1+1+1+1,
     /// If the module is compiled as static library.
     StaticLibrary : 1,
 
@@ -680,11 +680,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
 
     /// If the map from @objc provided name to top level swift::Decl in this
     /// module is populated
-    ObjCNameLookupCachePopulated : 1,
-
-    /// Whether the module is contained in the SDK or stdlib, or its a system
-    /// module and no SDK was specified.
-    IsNonUserModule : 1
+    ObjCNameLookupCachePopulated : 1
   );
 
   SWIFT_INLINE_BITFIELD(PrecedenceGroupDecl, Decl, 1+2,

include/swift/AST/Module.h

@@ -661,15 +661,9 @@ class ModuleDecl
   void setIsSystemModule(bool flag = true);
 
   /// \returns true if this module is part of the stdlib or contained within
-  /// the SDK. If no SDK was specified, also falls back to whether the module
-  /// was specified as a system module (ie. it's on the system search path).
-  bool isNonUserModule() const { return Bits.ModuleDecl.IsNonUserModule; }
-
-private:
-  /// Update whether this module is a non-user module, see \c isNonUserModule.
-  /// \p newUnit is the added unit that caused this update, or \c nullptr if
-  /// the update wasn't caused by adding a new unit.
-  void updateNonUserModule(FileUnit *newUnit);
+  /// the SDK. If no SDK was specified, falls back to whether the module was
+  /// specified as a system module (ie. it's on the system search path).
+  bool isNonUserModule() const;
 
 public:
   /// Returns true if the module was rebuilt from a module interface instead

include/swift/AST/TypeCheckRequests.h

@@ -4172,6 +4172,25 @@ void simple_display(llvm::raw_ostream &out, const TypeRepr *TyR);
 void simple_display(llvm::raw_ostream &out, ImplicitMemberAction action);
 void simple_display(llvm::raw_ostream &out, ResultBuilderBodyPreCheck pck);
 
+/// Computes whether a module is part of the stdlib or contained within the
+/// SDK. If no SDK was specified, falls back to whether the module was
+/// specified as a system module (ie. it's on the system search path).
+class IsNonUserModuleRequest
+    : public SimpleRequest<IsNonUserModuleRequest,
+                           bool(ModuleDecl *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  bool evaluate(Evaluator &evaluator, ModuleDecl *mod) const;
+
+public:
+  bool isCached() const { return true; }
+};
+
 #define SWIFT_TYPEID_ZONE TypeChecker
 #define SWIFT_TYPEID_HEADER "swift/AST/TypeCheckerTypeIDZone.def"
 #include "swift/Basic/DefineTypeIDZone.h"

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -466,3 +466,6 @@ SWIFT_REQUEST(TypeChecker, GetRuntimeDiscoverableAttributes,
 SWIFT_REQUEST(TypeChecker, LocalDiscriminatorsRequest,
               unsigned(DeclContext *),
               Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, IsNonUserModuleRequest,
+              bool(ModuleDecl *),
+              Cached, NoLocationInfo)

lib/AST/Module.cpp

@@ -605,49 +605,19 @@ ModuleDecl::ModuleDecl(Identifier name, ASTContext &ctx,
   Bits.ModuleDecl.HasHermeticSealAtLink = 0;
   Bits.ModuleDecl.IsConcurrencyChecked = 0;
   Bits.ModuleDecl.ObjCNameLookupCachePopulated = 0;
-  Bits.ModuleDecl.IsNonUserModule = 0;
 }
 
 void ModuleDecl::setIsSystemModule(bool flag) {
   Bits.ModuleDecl.IsSystemModule = flag;
-  updateNonUserModule(/*newFile=*/nullptr);
 }
 
-static bool prefixMatches(StringRef prefix, StringRef path) {
-  auto i = llvm::sys::path::begin(prefix), e = llvm::sys::path::end(prefix);
-  for (auto pi = llvm::sys::path::begin(path), pe = llvm::sys::path::end(path);
-       i != e && pi != pe; ++i, ++pi) {
-    if (*i != *pi)
-      return false;
-  }
-  return i == e;
-}
-
-void ModuleDecl::updateNonUserModule(FileUnit *newUnit) {
-  if (isNonUserModule())
-    return;
-
-  SearchPathOptions searchPathOpts = getASTContext().SearchPathOpts;
-  StringRef sdkPath = searchPathOpts.getSDKPath();
-
-  if (isStdlibModule() || (sdkPath.empty() && isSystemModule())) {
-    Bits.ModuleDecl.IsNonUserModule = true;
-    return;
-  }
+bool ModuleDecl::isNonUserModule() const {
+  // For clang submodules, retrieve their top level module (submodules have no
+  // source path, so we'd always return false for them).
+  ModuleDecl *mod = const_cast<ModuleDecl *>(this)->getTopLevelModule();
 
-  // If we loaded a serialized module, check if it was compiler adjacent or in
-  // the SDK.
-
-  auto *LF = dyn_cast_or_null<LoadedFile>(newUnit);
-  if (!LF)
-    return;
-
-  StringRef runtimePath = searchPathOpts.RuntimeResourcePath;
-  StringRef modulePath = LF->getSourceFilename();
-  if ((!runtimePath.empty() && prefixMatches(runtimePath, modulePath)) ||
-      (!sdkPath.empty() && prefixMatches(sdkPath, modulePath))) {
-    Bits.ModuleDecl.IsNonUserModule = true;
-  }
+  auto &evaluator = getASTContext().evaluator;
+  return evaluateOrDefault(evaluator, IsNonUserModuleRequest{mod}, false);
 }
 
 ImplicitImportList ModuleDecl::getImplicitImports() const {
@@ -669,8 +639,6 @@ void ModuleDecl::addFile(FileUnit &newFile) {
          cast<SourceFile>(newFile).Kind == SourceFileKind::SIL);
   Files.push_back(&newFile);
   clearLookupCache();
-
-  updateNonUserModule(&newFile);
 }
 
 void ModuleDecl::addAuxiliaryFile(SourceFile &sourceFile) {
@@ -4133,3 +4101,45 @@ const UnifiedStatsReporter::TraceFormatter*
 FrontendStatsTracer::getTraceFormatter<const SourceFile *>() {
   return &TF;
 }
+
+static bool prefixMatches(StringRef prefix, StringRef path) {
+  auto prefixIt = llvm::sys::path::begin(prefix),
+       prefixEnd = llvm::sys::path::end(prefix);
+  for (auto pathIt = llvm::sys::path::begin(path),
+            pathEnd = llvm::sys::path::end(path);
+       prefixIt != prefixEnd && pathIt != pathEnd; ++prefixIt, ++pathIt) {
+    if (*prefixIt != *pathIt)
+      return false;
+  }
+  return prefixIt == prefixEnd;
+}
+
+bool IsNonUserModuleRequest::evaluate(Evaluator &evaluator, ModuleDecl *mod) const {
+  // stdlib is non-user by definition
+  if (mod->isStdlibModule())
+    return true;
+  
+  // If there's no SDK path, fallback to checking whether the module was
+  // in the system search path or a clang system module
+  SearchPathOptions &searchPathOpts = mod->getASTContext().SearchPathOpts;
+  StringRef sdkPath = searchPathOpts.getSDKPath();
+  if (sdkPath.empty() && mod->isSystemModule())
+    return true;
+
+  // Some temporary module's get created with no module name and they have no
+  // files. Avoid running `getFiles` on them (which will assert if there
+  // aren't any).
+  if (!mod->hasName() || mod->getFiles().empty())
+    return false;
+  
+  auto *LF = dyn_cast_or_null<LoadedFile>(mod->getFiles().front());
+  if (!LF)
+    return false;
+  
+  StringRef modulePath = LF->getSourceFilename();
+  if (modulePath.empty())
+    return false;
+
+  StringRef runtimePath = searchPathOpts.RuntimeResourcePath;
+  return (!runtimePath.empty() && prefixMatches(runtimePath, modulePath)) || (!sdkPath.empty() && prefixMatches(sdkPath, modulePath));
+}

lib/IDE/CompletionLookup.cpp

@@ -291,6 +291,7 @@ void CompletionLookup::addSubModuleNames(
     CodeCompletionResultBuilder Builder(
         Sink, CodeCompletionResultKind::Declaration, SemanticContextKind::None);
     auto MD = ModuleDecl::create(Ctx.getIdentifier(Pair.first), Ctx);
+    MD->setFailedToLoad();
     Builder.setAssociatedDecl(MD);
     Builder.addBaseName(MD->getNameStr());
     Builder.addTypeAnnotation("Module");
@@ -365,6 +366,8 @@ void CompletionLookup::addImportModuleNames() {
       continue;
 
     auto MD = ModuleDecl::create(ModuleName, Ctx);
+    MD->setFailedToLoad();
+
     Optional<ContextualNotRecommendedReason> Reason = None;
 
     // Imported modules are not recommended.

test/IDE/complete_diagnostics.swift

@@ -77,7 +77,7 @@ import MyModule
 import #^IMPORT^#;
 // IMPORT-DAG: Decl[Module]/None/NotRecommended:   MyModule[#Module#]; name=MyModule; diagnostics=warning:module 'MyModule' is already imported{{$}}
 // IMPORT-DAG: Decl[Module]/None/NotRecommended:   OtherModule[#Module#]; name=OtherModule; diagnostics=note:module 'OtherModule' is already imported via another module import{{$}}
-// IMPORT-DAG: Decl[Module]/None/NotRecommended:   Swift[#Module#]; name=Swift; diagnostics=warning:module 'Swift' is already imported{{$}}
+// IMPORT-DAG: Decl[Module]/None/NotRecommended/IsSystem:   Swift[#Module#]; name=Swift; diagnostics=warning:module 'Swift' is already imported{{$}}
 
 func test(foo: Foo) {
   foo.#^MEMBER^#