clang/lib/Parse/ParseAST.cpp

   1 //===--- ParseAST.cpp - Provide the clang::ParseAST method ----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the clang::ParseAST method.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "clang/Parse/ParseAST.h"
  14 #include "clang/AST/ASTConsumer.h"
  15 #include "clang/AST/ASTContext.h"
  16 #include "clang/AST/ExternalASTSource.h"
  17 #include "clang/AST/Stmt.h"
  18 #include "clang/Parse/ParseDiagnostic.h"
  19 #include "clang/Parse/Parser.h"
  20 #include "clang/Sema/CodeCompleteConsumer.h"
  21 #include "clang/Sema/Sema.h"
  22 #include "clang/Sema/SemaConsumer.h"
  23 #include "clang/Sema/TemplateInstCallback.h"
  24 #include "llvm/Support/CrashRecoveryContext.h"
  25 #include "llvm/Support/TimeProfiler.h"
  26 #include <cstdio>
  27 #include <memory>
  28
  29 using namespace clang;
  30
  31 namespace {
  32
  33 /// Resets LLVM's pretty stack state so that stack traces are printed correctly
  34 /// when there are nested CrashRecoveryContexts and the inner one recovers from
  35 /// a crash.
  36 class ResetStackCleanup
  37     : public llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup,
  38                                                    const void> {
  39 public:
  40   ResetStackCleanup(llvm::CrashRecoveryContext *Context, const void *Top)
  41       : llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup, const void>(
  42             Context, Top) {}
  43   void recoverResources() override {
  44     llvm::RestorePrettyStackState(resource);
  45   }
  46 };
  47
  48 /// If a crash happens while the parser is active, an entry is printed for it.
  49 class PrettyStackTraceParserEntry : public llvm::PrettyStackTraceEntry {
  50   const Parser &P;
  51 public:
  52   PrettyStackTraceParserEntry(const Parser &p) : P(p) {}
  53   void print(raw_ostream &OS) const override;
  54 };
  55
  56 /// If a crash happens while the parser is active, print out a line indicating
  57 /// what the current token is.
  58 void PrettyStackTraceParserEntry::print(raw_ostream &OS) const {
  59   const Token &Tok = P.getCurToken();
  60   if (Tok.is(tok::eof)) {
  61     OS << "<eof> parser at end of file\n";
  62     return;
  63   }
  64
  65   if (Tok.getLocation().isInvalid()) {
  66     OS << "<unknown> parser at unknown location\n";
  67     return;
  68   }
  69
  70   const Preprocessor &PP = P.getPreprocessor();
  71   Tok.getLocation().print(OS, PP.getSourceManager());
  72   if (Tok.isAnnotation()) {
  73     OS << ": at annotation token\n";
  74   } else {
  75     // Do the equivalent of PP.getSpelling(Tok) except for the parts that would
  76     // allocate memory.
  77     bool Invalid = false;
  78     const SourceManager &SM = P.getPreprocessor().getSourceManager();
  79     unsigned Length = Tok.getLength();
  80     const char *Spelling = SM.getCharacterData(Tok.getLocation(), &Invalid);
  81     if (Invalid) {
  82       OS << ": unknown current parser token\n";
  83       return;
  84     }
  85     OS << ": current parser token '" << StringRef(Spelling, Length) << "'\n";
  86   }
  87 }
  88
  89 }  // namespace
  90
  91 //===----------------------------------------------------------------------===//
  92 // Public interface to the file
  93 //===----------------------------------------------------------------------===//
  94
  95 /// ParseAST - Parse the entire file specified, notifying the ASTConsumer as
  96 /// the file is parsed.  This inserts the parsed decls into the translation unit
  97 /// held by Ctx.
  98 ///
  99 void clang::ParseAST(Preprocessor &PP, ASTConsumer *Consumer,
 100                      ASTContext &Ctx, bool PrintStats,
 101                      TranslationUnitKind TUKind,
 102                      CodeCompleteConsumer *CompletionConsumer,
 103                      bool SkipFunctionBodies) {
 104
 105   std::unique_ptr<Sema> S(
 106       new Sema(PP, Ctx, *Consumer, TUKind, CompletionConsumer));
 107
 108   // Recover resources if we crash before exiting this method.
 109   llvm::CrashRecoveryContextCleanupRegistrar<Sema> CleanupSema(S.get());
 110
 111   ParseAST(*S.get(), PrintStats, SkipFunctionBodies);
 112 }
 113
 114 void clang::ParseAST(Sema &S, bool PrintStats, bool SkipFunctionBodies) {
 115   // Collect global stats on Decls/Stmts (until we have a module streamer).
 116   if (PrintStats) {
 117     Decl::EnableStatistics();
 118     Stmt::EnableStatistics();
 119   }
 120
 121   // Also turn on collection of stats inside of the Sema object.
 122   bool OldCollectStats = PrintStats;
 123   std::swap(OldCollectStats, S.CollectStats);
 124
 125   // Initialize the template instantiation observer chain.
 126   // FIXME: See note on "finalize" below.
 127   initialize(S.TemplateInstCallbacks, S);
 128
 129   ASTConsumer *Consumer = &S.getASTConsumer();
 130
 131   std::unique_ptr<Parser> ParseOP(
 132       new Parser(S.getPreprocessor(), S, SkipFunctionBodies));
 133   Parser &P = *ParseOP.get();
 134
 135   llvm::CrashRecoveryContextCleanupRegistrar<const void, ResetStackCleanup>
 136       CleanupPrettyStack(llvm::SavePrettyStackState());
 137   PrettyStackTraceParserEntry CrashInfo(P);
 138
 139   // Recover resources if we crash before exiting this method.
 140   llvm::CrashRecoveryContextCleanupRegistrar<Parser>
 141     CleanupParser(ParseOP.get());
 142
 143   S.getPreprocessor().EnterMainSourceFile();
 144   ExternalASTSource *External = S.getASTContext().getExternalSource();
 145   if (External)
 146     External->StartTranslationUnit(Consumer);
 147
 148   // If a PCH through header is specified that does not have an include in
 149   // the source, or a PCH is being created with #pragma hdrstop with nothing
 150   // after the pragma, there won't be any tokens or a Lexer.
 151   bool HaveLexer = S.getPreprocessor().getCurrentLexer();
 152
 153   if (HaveLexer) {
 154     llvm::TimeTraceScope TimeScope("Frontend");
 155     P.Initialize();
 156     Parser::DeclGroupPtrTy ADecl;
 157     Sema::ModuleImportState ImportState;
 158     EnterExpressionEvaluationContext PotentiallyEvaluated(
 159         S, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
 160
 161     for (bool AtEOF = P.ParseFirstTopLevelDecl(ADecl, ImportState); !AtEOF;
 162          AtEOF = P.ParseTopLevelDecl(ADecl, ImportState)) {
 163       // If we got a null return and something *was* parsed, ignore it.  This
 164       // is due to a top-level semicolon, an action override, or a parse error
 165       // skipping something.
 166       if (ADecl && !Consumer->HandleTopLevelDecl(ADecl.get()))
 167         return;
 168     }
 169   }
 170
 171   // Process any TopLevelDecls generated by #pragma weak.
 172   for (Decl *D : S.WeakTopLevelDecls())
 173     Consumer->HandleTopLevelDecl(DeclGroupRef(D));
 174
 175   // For C++20 modules, the codegen for module initializers needs to be altered
 176   // and to be able to use a name based on the module name.
 177
 178   // At this point, we should know if we are building a non-header C++20 module.
 179   if (S.getLangOpts().CPlusPlusModules) {
 180     // If we are building the module from source, then the top level module
 181     // will be here.
 182     Module *CodegenModule = S.getCurrentModule();
 183     bool Interface = true;
 184     if (CodegenModule)
 185       // We only use module initializers for importable module (including
 186       // partition implementation units).
 187       Interface = S.currentModuleIsInterface();
 188     else if (S.getLangOpts().isCompilingModuleInterface())
 189       // If we are building the module from a PCM file, then the module can be
 190       // found here.
 191       CodegenModule = S.getPreprocessor().getCurrentModule();
 192
 193     if (Interface && CodegenModule)
 194       S.getASTContext().setModuleForCodeGen(CodegenModule);
 195   }
 196   Consumer->HandleTranslationUnit(S.getASTContext());
 197
 198   // Finalize the template instantiation observer chain.
 199   // FIXME: This (and init.) should be done in the Sema class, but because
 200   // Sema does not have a reliable "Finalize" function (it has a
 201   // destructor, but it is not guaranteed to be called ("-disable-free")).
 202   // So, do the initialization above and do the finalization here:
 203   finalize(S.TemplateInstCallbacks, S);
 204
 205   std::swap(OldCollectStats, S.CollectStats);
 206   if (PrintStats) {
 207     llvm::errs() << "\nSTATISTICS:\n";
 208     if (HaveLexer) P.getActions().PrintStats();
 209     S.getASTContext().PrintStats();
 210     Decl::PrintStats();
 211     Stmt::PrintStats();
 212     Consumer->PrintStats();
 213   }
 214 }