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/ExternalASTSource.h"
18#include "clang/AST/Stmt.h"
19#include "clang/Parse/ParseDiagnostic.h"
20#include "clang/Parse/Parser.h"
21#include "clang/Sema/CodeCompleteConsumer.h"
22#include "clang/Sema/Sema.h"
23#include "clang/Sema/SemaConsumer.h"
24#include "llvm/Support/CrashRecoveryContext.h"
25#include <cstdio>
26#include <memory>
27
28using namespace clang;
29
30namespace {
31
32/// Resets LLVM's pretty stack state so that stack traces are printed correctly
33/// when there are nested CrashRecoveryContexts and the inner one recovers from
34/// a crash.
35class ResetStackCleanup
36    : public llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup,
37                                                   const void> {
38public:
39  ResetStackCleanup(llvm::CrashRecoveryContext *Context, const void *Top)
40      : llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup, const void>(
41            Context, Top) {}
42  void recoverResources() override {
43    llvm::RestorePrettyStackState(resource);
44  }
45};
46
47/// If a crash happens while the parser is active, an entry is printed for it.
48class PrettyStackTraceParserEntry : public llvm::PrettyStackTraceEntry {
49  const Parser &P;
50public:
51  PrettyStackTraceParserEntry(const Parser &p) : P(p) {}
52  void print(raw_ostream &OS) const override;
53};
54
55/// If a crash happens while the parser is active, print out a line indicating
56/// what the current token is.
57void PrettyStackTraceParserEntry::print(raw_ostream &OS) const {
58  const Token &Tok = P.getCurToken();
59  if (Tok.is(tok::eof)) {
60    OS << "<eof> parser at end of file\n";
61    return;
62  }
63
64  if (Tok.getLocation().isInvalid()) {
65    OS << "<unknown> parser at unknown location\n";
66    return;
67  }
68
69  const Preprocessor &PP = P.getPreprocessor();
70  Tok.getLocation().print(OS, PP.getSourceManager());
71  if (Tok.isAnnotation()) {
72    OS << ": at annotation token\n";
73  } else {
74    // Do the equivalent of PP.getSpelling(Tok) except for the parts that would
75    // allocate memory.
76    bool Invalid = false;
77    const SourceManager &SM = P.getPreprocessor().getSourceManager();
78    unsigned Length = Tok.getLength();
79    const char *Spelling = SM.getCharacterData(Tok.getLocation(), &Invalid);
80    if (Invalid) {
81      OS << ": unknown current parser token\n";
82      return;
83    }
84    OS << ": current parser token '" << StringRef(Spelling, Length) << "'\n";
85  }
86}
87
88}  // namespace
89
90//===----------------------------------------------------------------------===//
91// Public interface to the file
92//===----------------------------------------------------------------------===//
93
94/// ParseAST - Parse the entire file specified, notifying the ASTConsumer as
95/// the file is parsed.  This inserts the parsed decls into the translation unit
96/// held by Ctx.
97///
98void clang::ParseAST(Preprocessor &PP, ASTConsumer *Consumer,
99                     ASTContext &Ctx, bool PrintStats,
100                     TranslationUnitKind TUKind,
101                     CodeCompleteConsumer *CompletionConsumer,
102                     bool SkipFunctionBodies) {
103
104  std::unique_ptr<Sema> S(
105      new Sema(PP, Ctx, *Consumer, TUKind, CompletionConsumer));
106
107  // Recover resources if we crash before exiting this method.
108  llvm::CrashRecoveryContextCleanupRegistrar<Sema> CleanupSema(S.get());
109
110  ParseAST(*S.get(), PrintStats, SkipFunctionBodies);
111}
112
113void clang::ParseAST(Sema &S, bool PrintStats, bool SkipFunctionBodies) {
114  // Collect global stats on Decls/Stmts (until we have a module streamer).
115  if (PrintStats) {
116    Decl::EnableStatistics();
117    Stmt::EnableStatistics();
118  }
119
120  // Also turn on collection of stats inside of the Sema object.
121  bool OldCollectStats = PrintStats;
122  std::swap(OldCollectStats, S.CollectStats);
123
124  ASTConsumer *Consumer = &S.getASTConsumer();
125
126  std::unique_ptr<Parser> ParseOP(
127      new Parser(S.getPreprocessor(), S, SkipFunctionBodies));
128  Parser &P = *ParseOP.get();
129
130  llvm::CrashRecoveryContextCleanupRegistrar<const void, ResetStackCleanup>
131      CleanupPrettyStack(llvm::SavePrettyStackState());
132  PrettyStackTraceParserEntry CrashInfo(P);
133
134  // Recover resources if we crash before exiting this method.
135  llvm::CrashRecoveryContextCleanupRegistrar<Parser>
136    CleanupParser(ParseOP.get());
137
138  S.getPreprocessor().EnterMainSourceFile();
139  P.Initialize();
140
141  // C11 6.9p1 says translation units must have at least one top-level
142  // declaration. C++ doesn't have this restriction. We also don't want to
143  // complain if we have a precompiled header, although technically if the PCH
144  // is empty we should still emit the (pedantic) diagnostic.
145  Parser::DeclGroupPtrTy ADecl;
146  ExternalASTSource *External = S.getASTContext().getExternalSource();
147  if (External)
148    External->StartTranslationUnit(Consumer);
149
150  if (P.ParseTopLevelDecl(ADecl)) {
151    if (!External && !S.getLangOpts().CPlusPlus)
152      P.Diag(diag::ext_empty_translation_unit);
153  } else {
154    do {
155      // If we got a null return and something *was* parsed, ignore it.  This
156      // is due to a top-level semicolon, an action override, or a parse error
157      // skipping something.
158      if (ADecl && !Consumer->HandleTopLevelDecl(ADecl.get()))
159        return;
160    } while (!P.ParseTopLevelDecl(ADecl));
161  }
162
163  // Process any TopLevelDecls generated by #pragma weak.
164  for (Decl *D : S.WeakTopLevelDecls())
165    Consumer->HandleTopLevelDecl(DeclGroupRef(D));
166
167  Consumer->HandleTranslationUnit(S.getASTContext());
168
169  std::swap(OldCollectStats, S.CollectStats);
170  if (PrintStats) {
171    llvm::errs() << "\nSTATISTICS:\n";
172    P.getActions().PrintStats();
173    S.getASTContext().PrintStats();
174    Decl::PrintStats();
175    Stmt::PrintStats();
176    Consumer->PrintStats();
177  }
178}
179