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