1//===--- ParseAST.cpp - Provide the clang::ParseAST method ----------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the clang::ParseAST method.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Parse/ParseAST.h"
15#include "clang/AST/ASTConsumer.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/DeclCXX.h"
18#include "clang/AST/ExternalASTSource.h"
19#include "clang/AST/Stmt.h"
20#include "clang/Parse/ParseDiagnostic.h"
21#include "clang/Parse/Parser.h"
22#include "clang/Sema/CodeCompleteConsumer.h"
23#include "clang/Sema/ExternalSemaSource.h"
24#include "clang/Sema/Sema.h"
25#include "clang/Sema/SemaConsumer.h"
26#include "llvm/Support/CrashRecoveryContext.h"
27#include <cstdio>
28#include <memory>
29
30using namespace clang;
31
32namespace {
33
34/// If a crash happens while the parser is active, an entry is printed for it.
35class PrettyStackTraceParserEntry : public llvm::PrettyStackTraceEntry {
36  const Parser &P;
37public:
38  PrettyStackTraceParserEntry(const Parser &p) : P(p) {}
39  void print(raw_ostream &OS) const override;
40};
41
42/// If a crash happens while the parser is active, print out a line indicating
43/// what the current token is.
44void PrettyStackTraceParserEntry::print(raw_ostream &OS) const {
45  const Token &Tok = P.getCurToken();
46  if (Tok.is(tok::eof)) {
47    OS << "<eof> parser at end of file\n";
48    return;
49  }
50
51  if (Tok.getLocation().isInvalid()) {
52    OS << "<unknown> parser at unknown location\n";
53    return;
54  }
55
56  const Preprocessor &PP = P.getPreprocessor();
57  Tok.getLocation().print(OS, PP.getSourceManager());
58  if (Tok.isAnnotation()) {
59    OS << ": at annotation token\n";
60  } else {
61    // Do the equivalent of PP.getSpelling(Tok) except for the parts that would
62    // allocate memory.
63    bool Invalid = false;
64    const SourceManager &SM = P.getPreprocessor().getSourceManager();
65    unsigned Length = Tok.getLength();
66    const char *Spelling = SM.getCharacterData(Tok.getLocation(), &Invalid);
67    if (Invalid) {
68      OS << ": unknown current parser token\n";
69      return;
70    }
71    OS << ": current parser token '" << StringRef(Spelling, Length) << "'\n";
72  }
73}
74
75}  // namespace
76
77//===----------------------------------------------------------------------===//
78// Public interface to the file
79//===----------------------------------------------------------------------===//
80
81/// ParseAST - Parse the entire file specified, notifying the ASTConsumer as
82/// the file is parsed.  This inserts the parsed decls into the translation unit
83/// held by Ctx.
84///
85void clang::ParseAST(Preprocessor &PP, ASTConsumer *Consumer,
86                     ASTContext &Ctx, bool PrintStats,
87                     TranslationUnitKind TUKind,
88                     CodeCompleteConsumer *CompletionConsumer,
89                     bool SkipFunctionBodies) {
90
91  std::unique_ptr<Sema> S(
92      new Sema(PP, Ctx, *Consumer, TUKind, CompletionConsumer));
93
94  // Recover resources if we crash before exiting this method.
95  llvm::CrashRecoveryContextCleanupRegistrar<Sema> CleanupSema(S.get());
96
97  ParseAST(*S.get(), PrintStats, SkipFunctionBodies);
98}
99
100void clang::ParseAST(Sema &S, bool PrintStats, bool SkipFunctionBodies) {
101  // Collect global stats on Decls/Stmts (until we have a module streamer).
102  if (PrintStats) {
103    Decl::EnableStatistics();
104    Stmt::EnableStatistics();
105  }
106
107  // Also turn on collection of stats inside of the Sema object.
108  bool OldCollectStats = PrintStats;
109  std::swap(OldCollectStats, S.CollectStats);
110
111  ASTConsumer *Consumer = &S.getASTConsumer();
112
113  std::unique_ptr<Parser> ParseOP(
114      new Parser(S.getPreprocessor(), S, SkipFunctionBodies));
115  Parser &P = *ParseOP.get();
116
117  PrettyStackTraceParserEntry CrashInfo(P);
118
119  // Recover resources if we crash before exiting this method.
120  llvm::CrashRecoveryContextCleanupRegistrar<Parser>
121    CleanupParser(ParseOP.get());
122
123  S.getPreprocessor().EnterMainSourceFile();
124  P.Initialize();
125
126  // C11 6.9p1 says translation units must have at least one top-level
127  // declaration. C++ doesn't have this restriction. We also don't want to
128  // complain if we have a precompiled header, although technically if the PCH
129  // is empty we should still emit the (pedantic) diagnostic.
130  Parser::DeclGroupPtrTy ADecl;
131  ExternalASTSource *External = S.getASTContext().getExternalSource();
132  if (External)
133    External->StartTranslationUnit(Consumer);
134
135  if (P.ParseTopLevelDecl(ADecl)) {
136    if (!External && !S.getLangOpts().CPlusPlus)
137      P.Diag(diag::ext_empty_translation_unit);
138  } else {
139    do {
140      // If we got a null return and something *was* parsed, ignore it.  This
141      // is due to a top-level semicolon, an action override, or a parse error
142      // skipping something.
143      if (ADecl && !Consumer->HandleTopLevelDecl(ADecl.get()))
144        return;
145    } while (!P.ParseTopLevelDecl(ADecl));
146  }
147
148  // Process any TopLevelDecls generated by #pragma weak.
149  for (SmallVectorImpl<Decl *>::iterator
150       I = S.WeakTopLevelDecls().begin(),
151       E = S.WeakTopLevelDecls().end(); I != E; ++I)
152    Consumer->HandleTopLevelDecl(DeclGroupRef(*I));
153
154  Consumer->HandleTranslationUnit(S.getASTContext());
155
156  std::swap(OldCollectStats, S.CollectStats);
157  if (PrintStats) {
158    llvm::errs() << "\nSTATISTICS:\n";
159    P.getActions().PrintStats();
160    S.getASTContext().PrintStats();
161    Decl::PrintStats();
162    Stmt::PrintStats();
163    Consumer->PrintStats();
164  }
165}
166