Requestify the loading of access notes

Replace `loadAccessNotesIfNeeded` with a request that loads the access
notes on-demand.

Author: hamishknight

include/swift/AST/ASTContext.h

@@ -1626,6 +1626,10 @@ class ASTContext final {
   AvailabilityDomain getTargetAvailabilityDomain() const;
 };
 
+inline SourceLoc extractNearestSourceLoc(const ASTContext *ctx) {
+  return SourceLoc();
+}
+
 } // end namespace swift
 
 #endif

include/swift/AST/DiagnosticsFrontend.def

@@ -565,9 +565,6 @@ WARNING(module_incompatible_with_skip_function_bodies,none,
         "-experimental-skip-*-function-bodies* flags; they have "
         "been automatically disabled", (StringRef))
 
-WARNING(access_notes_file_io_error,none,
-        "ignored access notes file at '%0' because it cannot be read: %1",
-        (StringRef, StringRef))
 WARNING(error_in_access_notes_file,none,
         "ignored access notes file because it cannot be parsed: %0",
         (StringRef))

include/swift/AST/DiagnosticsSema.def

@@ -7853,6 +7853,10 @@ ERROR(atomics_ordering_must_be_constant, none,
 
 #define WHICH_ACCESS_NOTE(reason) "specified by access note for %" #reason
 
+WARNING(access_notes_file_io_error,none,
+        "ignored access notes file at '%0' because it cannot be read: %1",
+        (StringRef, StringRef))
+
 REMARK(attr_added_by_access_note, none,
        "implicitly added '%1' to this %kindonly2, as " WHICH_ACCESS_NOTE(0),
        (StringRef, StringRef, const ValueDecl *))

include/swift/AST/Module.h

@@ -345,8 +345,6 @@ class ModuleDecl
   /// \see EntryPointInfoTy
   EntryPointInfoTy EntryPointInfo;
 
-  AccessNotesFile accessNotes;
-
   /// Used by the debugger to bypass resilient access to fields.
   bool BypassResilience = false;
 
@@ -415,8 +413,9 @@ class ModuleDecl
   /// imports.
   ImplicitImportList getImplicitImports() const;
 
-  AccessNotesFile &getAccessNotes() { return accessNotes; }
-  const AccessNotesFile &getAccessNotes() const { return accessNotes; }
+  /// Retrieve the access notes to apply for the module, or \c nullptr if there
+  /// are no access notes.
+  const AccessNotesFile *getAccessNotes() const;
 
   /// Return whether the module was imported with resilience disabled. The
   /// debugger does this to access private fields.

include/swift/AST/TypeCheckRequests.h

@@ -4089,6 +4089,31 @@ class PrimarySourceFilesRequest
   bool isCached() const { return true; }
 };
 
+/// Load the access notes to apply for the main module.
+///
+/// Note this is keyed on the ASTContext instead of the ModuleDecl to avoid
+/// needing to re-load the access notes in cases where we have multiple main
+/// modules, e.g when doing cached top-level code completion.
+///
+/// FIXME: This isn't really a type-checking request, if we ever split off a
+/// zone for more general requests, this should be moved there.
+class LoadAccessNotesRequest
+    : public SimpleRequest<LoadAccessNotesRequest,
+                           const AccessNotesFile *(ASTContext *),
+                           RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  const AccessNotesFile *evaluate(Evaluator &evaluator, ASTContext *ctx) const;
+
+public:
+  // Cached.
+  bool isCached() const { return true; }
+};
+
 /// Kinds of types for CustomAttr.
 enum class CustomAttrTypeKind {
   /// The type is required to not be expressed in terms of

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -275,6 +275,8 @@ SWIFT_REQUEST(TypeChecker, PatternBindingCheckedAndContextualizedInitRequest,
               SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, PrimarySourceFilesRequest,
               ArrayRef<SourceFile *>(ModuleDecl *), Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, LoadAccessNotesRequest,
+              const AccessNotesFile *(ASTContext *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, PropertyWrapperAuxiliaryVariablesRequest,
               PropertyWrapperAuxiliaryVariables(VarDecl *),
               SeparatelyCached | SplitCached,

include/swift/Frontend/Frontend.h

@@ -790,11 +790,6 @@ class CompilerInstance {
   /// Parses and type-checks all input files.
   void performSema();
 
-  /// Loads any access notes for the main module.
-  ///
-  /// FIXME: This should be requestified.
-  void loadAccessNotesIfNeeded();
-
   /// Parses and performs import resolution on all input files.
   ///
   /// This is similar to a parse-only invocation, but module imports will also

lib/AST/Module.cpp

@@ -823,6 +823,16 @@ ImplicitImportList ModuleDecl::getImplicitImports() const {
                            {});
 }
 
+const AccessNotesFile *ModuleDecl::getAccessNotes() const {
+  // Only the main module has access notes.
+  if (!isMainModule())
+    return nullptr;
+
+  auto &ctx = getASTContext();
+  return evaluateOrDefault(ctx.evaluator, LoadAccessNotesRequest{&ctx},
+                           nullptr);
+}
+
 SourceFile *ModuleDecl::getSourceFileContainingLocation(SourceLoc loc) {
   if (loc.isInvalid())
     return nullptr;

lib/Frontend/Frontend.cpp

@@ -1553,38 +1553,13 @@ void CompilerInstance::setMainModule(ModuleDecl *newMod) {
   Context->MainModule = newMod;
 }
 
-void CompilerInstance::loadAccessNotesIfNeeded() {
-  if (Invocation.getLangOptions().AccessNotesPath.empty())
-    return;
-
-  auto *mainModule = getMainModule();
-
-  auto accessNotesPath = Invocation.getLangOptions().AccessNotesPath;
-
-  auto bufferOrError =
-      swift::vfs::getFileOrSTDIN(getFileSystem(), accessNotesPath);
-  if (bufferOrError) {
-    int sourceID = SourceMgr.addNewSourceBuffer(std::move(bufferOrError.get()));
-    auto buffer = SourceMgr.getLLVMSourceMgr().getMemoryBuffer(sourceID);
-
-    if (auto accessNotesFile = AccessNotesFile::load(*Context, buffer))
-      mainModule->getAccessNotes() = *accessNotesFile;
-  } else {
-    Diagnostics.diagnose(SourceLoc(), diag::access_notes_file_io_error,
-                         accessNotesPath, bufferOrError.getError().message());
-  }
-}
-
 bool CompilerInstance::performParseAndResolveImportsOnly() {
   FrontendStatsTracer tracer(getStatsReporter(), "parse-and-resolve-imports");
 
   // NOTE: Do not add new logic to this function, use the request evaluator to
   // lazily evaluate instead. Once the below computations are requestified we
   // ought to be able to remove this function.
 
-  // Load access notes.
-  loadAccessNotesIfNeeded();
-
   // Resolve imports for all the source files in the module.
   auto *mainModule = getMainModule();
   performImportResolution(mainModule);

lib/IDETool/IDEInspectionInstance.cpp

@@ -517,7 +517,6 @@ void IDEInspectionInstance::performNewOperation(
     CI->getASTContext().CancellationFlag = CancellationFlag;
     registerIDERequestFunctions(CI->getASTContext().evaluator);
 
-    CI->loadAccessNotesIfNeeded();
     performImportResolution(CI->getMainModule());
 
     bool DidFindIDEInspectionTarget = CI->getIDEInspectionFile()