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//===--- ParseAST.cpp - Provide the clang::ParseAST method ----------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See 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> {
ResetStackCleanup(llvm::CrashRecoveryContext *Context, const void *Top)
: llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup, const void>(
Context, Top) {}
void recoverResources() override {
/// If a crash happens while the parser is active, an entry is printed for it.
class PrettyStackTraceParserEntry : public llvm::PrettyStackTraceEntry {
const Parser &P;
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 ( {
OS << "<eof> parser at end of file\n";
if (Tok.getLocation().isInvalid()) {
OS << "<unknown> parser at unknown location\n";
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";
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) {
// 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>
PrettyStackTraceParserEntry CrashInfo(P);
// Recover resources if we crash before exiting this method.
ExternalASTSource *External = S.getASTContext().getExternalSource();
if (External)
// 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");
Parser::DeclGroupPtrTy ADecl;
Sema::ModuleImportState ImportState;
EnterExpressionEvaluationContext PotentiallyEvaluated(
S, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
for (bool AtEOF = P.ParseFirstTopLevelDecl(ADecl, ImportState); !AtEOF;
AtEOF = P.ParseTopLevelDecl(ADecl, ImportState)) {
// 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()))
// Process any TopLevelDecls generated by #pragma weak.
for (Decl *D : S.WeakTopLevelDecls())
// 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();