--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/lib/Parse/ParseAST.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,189 @@
+//===--- ParseAST.cpp - Provide the clang::ParseAST method ----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the clang::ParseAST method.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Parse/ParseAST.h"
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/ExternalASTSource.h"
+#include "clang/AST/Stmt.h"
+#include "clang/Parse/ParseDiagnostic.h"
+#include "clang/Parse/Parser.h"
+#include "clang/Sema/CodeCompleteConsumer.h"
+#include "clang/Sema/Sema.h"
+#include "clang/Sema/SemaConsumer.h"
+#include "clang/Sema/TemplateInstCallback.h"
+#include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/Support/TimeProfiler.h"
+#include <cstdio>
+#include <memory>
+
+using namespace clang;
+
+namespace {
+
+/// Resets LLVM's pretty stack state so that stack traces are printed correctly
+/// when there are nested CrashRecoveryContexts and the inner one recovers from
+/// a crash.
+class ResetStackCleanup
+    : public llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup,
+                                                   const void> {
+public:
+  ResetStackCleanup(llvm::CrashRecoveryContext *Context, const void *Top)
+      : llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup, const void>(
+            Context, Top) {}
+  void recoverResources() override {
+    llvm::RestorePrettyStackState(resource);
+  }
+};
+
+/// If a crash happens while the parser is active, an entry is printed for it.
+class PrettyStackTraceParserEntry : public llvm::PrettyStackTraceEntry {
+  const Parser &P;
+public:
+  PrettyStackTraceParserEntry(const Parser &p) : P(p) {}
+  void print(raw_ostream &OS) const override;
+};
+
+/// If a crash happens while the parser is active, print out a line indicating
+/// what the current token is.
+void PrettyStackTraceParserEntry::print(raw_ostream &OS) const {
+  const Token &Tok = P.getCurToken();
+  if (Tok.is(tok::eof)) {
+    OS << "<eof> parser at end of file\n";
+    return;
+  }
+
+  if (Tok.getLocation().isInvalid()) {
+    OS << "<unknown> parser at unknown location\n";
+    return;
+  }
+
+  const Preprocessor &PP = P.getPreprocessor();
+  Tok.getLocation().print(OS, PP.getSourceManager());
+  if (Tok.isAnnotation()) {
+    OS << ": at annotation token\n";
+  } else {
+    // Do the equivalent of PP.getSpelling(Tok) except for the parts that would
+    // allocate memory.
+    bool Invalid = false;
+    const SourceManager &SM = P.getPreprocessor().getSourceManager();
+    unsigned Length = Tok.getLength();
+    const char *Spelling = SM.getCharacterData(Tok.getLocation(), &Invalid);
+    if (Invalid) {
+      OS << ": unknown current parser token\n";
+      return;
+    }
+    OS << ": current parser token '" << StringRef(Spelling, Length) << "'\n";
+  }
+}
+
+}  // namespace
+
+//===----------------------------------------------------------------------===//
+// Public interface to the file
+//===----------------------------------------------------------------------===//
+
+/// ParseAST - Parse the entire file specified, notifying the ASTConsumer as
+/// the file is parsed.  This inserts the parsed decls into the translation unit
+/// held by Ctx.
+///
+void clang::ParseAST(Preprocessor &PP, ASTConsumer *Consumer,
+                     ASTContext &Ctx, bool PrintStats,
+                     TranslationUnitKind TUKind,
+                     CodeCompleteConsumer *CompletionConsumer,
+                     bool SkipFunctionBodies) {
+
+  std::unique_ptr<Sema> S(
+      new Sema(PP, Ctx, *Consumer, TUKind, CompletionConsumer));
+
+  // Recover resources if we crash before exiting this method.
+  llvm::CrashRecoveryContextCleanupRegistrar<Sema> CleanupSema(S.get());
+
+  ParseAST(*S.get(), PrintStats, SkipFunctionBodies);
+}
+
+void clang::ParseAST(Sema &S, bool PrintStats, bool SkipFunctionBodies) {
+  // Collect global stats on Decls/Stmts (until we have a module streamer).
+  if (PrintStats) {
+    Decl::EnableStatistics();
+    Stmt::EnableStatistics();
+  }
+
+  // Also turn on collection of stats inside of the Sema object.
+  bool OldCollectStats = PrintStats;
+  std::swap(OldCollectStats, S.CollectStats);
+
+  // Initialize the template instantiation observer chain.
+  // FIXME: See note on "finalize" below.
+  initialize(S.TemplateInstCallbacks, S);
+
+  ASTConsumer *Consumer = &S.getASTConsumer();
+
+  std::unique_ptr<Parser> ParseOP(
+      new Parser(S.getPreprocessor(), S, SkipFunctionBodies));
+  Parser &P = *ParseOP.get();
+
+  llvm::CrashRecoveryContextCleanupRegistrar<const void, ResetStackCleanup>
+      CleanupPrettyStack(llvm::SavePrettyStackState());
+  PrettyStackTraceParserEntry CrashInfo(P);
+
+  // Recover resources if we crash before exiting this method.
+  llvm::CrashRecoveryContextCleanupRegistrar<Parser>
+    CleanupParser(ParseOP.get());
+
+  S.getPreprocessor().EnterMainSourceFile();
+  ExternalASTSource *External = S.getASTContext().getExternalSource();
+  if (External)
+    External->StartTranslationUnit(Consumer);
+
+  // If a PCH through header is specified that does not have an include in
+  // the source, or a PCH is being created with #pragma hdrstop with nothing
+  // after the pragma, there won't be any tokens or a Lexer.
+  bool HaveLexer = S.getPreprocessor().getCurrentLexer();
+
+  if (HaveLexer) {
+    llvm::TimeTraceScope TimeScope("Frontend");
+    P.Initialize();
+    Parser::DeclGroupPtrTy ADecl;
+    for (bool AtEOF = P.ParseFirstTopLevelDecl(ADecl); !AtEOF;
+         AtEOF = P.ParseTopLevelDecl(ADecl)) {
+      // If we got a null return and something *was* parsed, ignore it.  This
+      // is due to a top-level semicolon, an action override, or a parse error
+      // skipping something.
+      if (ADecl && !Consumer->HandleTopLevelDecl(ADecl.get()))
+        return;
+    }
+  }
+
+  // Process any TopLevelDecls generated by #pragma weak.
+  for (Decl *D : S.WeakTopLevelDecls())
+    Consumer->HandleTopLevelDecl(DeclGroupRef(D));
+
+  Consumer->HandleTranslationUnit(S.getASTContext());
+
+  // Finalize the template instantiation observer chain.
+  // FIXME: This (and init.) should be done in the Sema class, but because
+  // Sema does not have a reliable "Finalize" function (it has a
+  // destructor, but it is not guaranteed to be called ("-disable-free")).
+  // So, do the initialization above and do the finalization here:
+  finalize(S.TemplateInstCallbacks, S);
+
+  std::swap(OldCollectStats, S.CollectStats);
+  if (PrintStats) {
+    llvm::errs() << "\nSTATISTICS:\n";
+    if (HaveLexer) P.getActions().PrintStats();
+    S.getASTContext().PrintStats();
+    Decl::PrintStats();
+    Stmt::PrintStats();
+    Consumer->PrintStats();
+  }
+}