[Frontend] Remove performParseOnly

Most clients were only using it to populate the
main module with files, which is now done by
`getMainModule`. Instead, they can now just rely
on parsing happening lazily.

Author: hamishknight

include/swift/AST/SourceFile.h

@@ -490,7 +490,7 @@ class SourceFile final : public FileUnit {
   }
 
   SWIFT_DEBUG_DUMP;
-  void dump(raw_ostream &os) const;
+  void dump(raw_ostream &os, bool parseIfNeeded = false) const;
 
   /// Pretty-print the contents of this source file.
   ///

include/swift/Frontend/Frontend.h

@@ -616,9 +616,6 @@ class CompilerInstance {
   /// Parses and type-checks all input files.
   void performSema();
 
-  /// Parses the input file but does no type-checking or module imports.
-  void performParseOnly();
-
   /// Parses and performs import resolution on all input files.
   ///
   /// This is similar to a parse-only invocation, but module imports will also

lib/AST/ASTDumper.cpp

@@ -1420,7 +1420,13 @@ void SourceFile::dump() const {
   dump(llvm::errs());
 }
 
-void SourceFile::dump(llvm::raw_ostream &OS) const {
+void SourceFile::dump(llvm::raw_ostream &OS, bool parseIfNeeded) const {
+  // If we're allowed to parse the SourceFile, do so now. We need to force the
+  // parsing request as by default the dumping logic tries not to kick any
+  // requests.
+  if (parseIfNeeded)
+    (void)getTopLevelDecls();
+
   PrintDecl(OS).visitSourceFile(*this);
   llvm::errs() << '\n';
 }

lib/Frontend/Frontend.cpp

@@ -776,16 +776,6 @@ void CompilerInstance::setMainModule(ModuleDecl *newMod) {
   Context->LoadedModules[newMod->getName()] = newMod;
 }
 
-void CompilerInstance::performParseOnly() {
-  const InputFileKind Kind = Invocation.getInputKind();
-  assert((Kind == InputFileKind::Swift || Kind == InputFileKind::SwiftLibrary ||
-          Kind == InputFileKind::SwiftModuleInterface) &&
-         "only supports parsing .swift files");
-  (void)Kind;
-
-  performSemaUpTo(SourceFile::Unprocessed);
-}
-
 void CompilerInstance::performParseAndResolveImportsOnly() {
   performSemaUpTo(SourceFile::ImportsResolved);
 }

lib/FrontendTool/FrontendTool.cpp

@@ -510,11 +510,6 @@ getFileOutputStream(StringRef OutputFilename, ASTContext &Ctx) {
 
 /// Writes the Syntax tree to the given file
 static bool emitSyntax(SourceFile *SF, StringRef OutputFilename) {
-  auto bufferID = SF->getBufferID();
-  assert(bufferID && "frontend should have a buffer ID "
-         "for the main source file");
-  (void)bufferID;
-
   auto os = getFileOutputStream(OutputFilename, SF->getASTContext());
   if (!os) return true;
 
@@ -884,12 +879,13 @@ static void dumpAST(CompilerInstance &Instance) {
       auto PSPs = Instance.getPrimarySpecificPathsForSourceFile(*sourceFile);
       auto OutputFilename = PSPs.OutputFilename;
       auto OS = getFileOutputStream(OutputFilename, Instance.getASTContext());
-      sourceFile->dump(*OS);
+      sourceFile->dump(*OS, /*parseIfNeeded*/ true);
     }
   } else {
     // Some invocations don't have primary files. In that case, we default to
     // looking for the main file and dumping it to `stdout`.
-    getPrimaryOrMainSourceFile(Instance)->dump(llvm::outs());
+    auto *SF = getPrimaryOrMainSourceFile(Instance);
+    SF->dump(llvm::outs(), /*parseIfNeeded*/ true);
   }
 }
 
@@ -1292,16 +1288,30 @@ static bool performCompile(CompilerInstance &Instance,
   };
 
   if (FrontendOptions::shouldActionOnlyParse(Action)) {
-    Instance.performParseOnly();
+    // Parsing gets triggered lazily, but let's make sure we have the right
+    // input kind.
+    auto kind = Invocation.getInputKind();
+    assert((kind == InputFileKind::Swift ||
+            kind == InputFileKind::SwiftLibrary ||
+            kind == InputFileKind::SwiftModuleInterface) &&
+           "Only supports parsing .swift files");
+    (void)kind;
   } else if (Action == FrontendOptions::ActionType::ResolveImports) {
     Instance.performParseAndResolveImportsOnly();
   } else {
     Instance.performSema();
   }
 
   ASTContext &Context = Instance.getASTContext();
-  if (Action == FrontendOptions::ActionType::Parse)
+  if (Action == FrontendOptions::ActionType::Parse) {
+    // A -parse invocation only cares about the side effects of parsing, so
+    // force the parsing of all the source files.
+    for (auto *file : Instance.getMainModule()->getFiles()) {
+      if (auto *SF = dyn_cast<SourceFile>(file))
+        (void)SF->getTopLevelDecls();
+    }
     return Context.hadError();
+  }
 
   if (Action == FrontendOptions::ActionType::ScanDependencies) {
     scanDependencies(Instance);

lib/IDE/Refactoring.cpp

@@ -1180,8 +1180,6 @@ getNotableRegions(StringRef SourceText, unsigned NameOffset, StringRef Name,
   if (Instance->setup(Invocation))
     llvm_unreachable("Failed setup");
 
-  Instance->performParseOnly();
-
   unsigned BufferId = Instance->getPrimarySourceFile()->getBufferID().getValue();
   SourceManager &SM = Instance->getSourceMgr();
   SourceLoc NameLoc = SM.getLocForOffset(BufferId, NameOffset);

tools/SourceKit/lib/SwiftLang/SwiftDocSupport.cpp

@@ -814,10 +814,7 @@ static bool makeParserAST(CompilerInstance &CI, StringRef Text,
   Buf = llvm::MemoryBuffer::getMemBuffer(Text, "<module-interface>");
   Invocation.getFrontendOptions().InputsAndOutputs.addInput(
       InputFile(Buf.get()->getBufferIdentifier(), false, Buf.get()));
-  if (CI.setup(Invocation))
-    return true;
-  CI.performParseOnly();
-  return false;
+  return CI.setup(Invocation);
 }
 
 static void collectFuncEntities(std::vector<TextEntity> &Ents,
@@ -1407,7 +1404,6 @@ SourceFile *SwiftLangSupport::getSyntacticSourceFile(
     Error = "Compiler invocation set up failed";
     return nullptr;
   }
-  ParseCI.performParseOnly();
 
   SourceFile *SF = nullptr;
   unsigned BufferID = ParseCI.getInputBufferIDs().back();

tools/SourceKit/lib/SwiftLang/SwiftEditorInterfaceGen.cpp

@@ -240,10 +240,7 @@ static bool makeParserAST(CompilerInstance &CI, StringRef Text,
   Buf = llvm::MemoryBuffer::getMemBuffer(Text, "<module-interface>");
   Invocation.getFrontendOptions().InputsAndOutputs.addInput(
       InputFile(Buf.get()->getBufferIdentifier(), false, Buf.get()));
-  if (CI.setup(Invocation))
-    return true;
-  CI.performParseOnly();
-  return false;
+  return CI.setup(Invocation);
 }
 
 static void reportSyntacticAnnotations(CompilerInstance &CI,

tools/swift-ide-test/swift-ide-test.cpp

@@ -1727,9 +1727,7 @@ static int doPrintAST(const CompilerInvocation &InitInvok,
     CI.getMainModule()->setDebugClient(DebuggerClient.get());
   }
 
-  if (!RunTypeChecker)
-    CI.performParseOnly();
-  else
+  if (RunTypeChecker)
     CI.performSema();
 
   if (MangledNameToFind.empty()) {

tools/swift-refactor/swift-refactor.cpp

@@ -268,7 +268,7 @@ int main(int argc, char *argv[]) {
   switch (options::Action) {
     case RefactoringKind::GlobalRename:
     case RefactoringKind::FindGlobalRenameRanges:
-      CI.performParseOnly();
+      // No type-checking required.
       break;
     default:
       CI.performSema();