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/Parser.h"
19#include "clang/Sema/CodeCompleteConsumer.h"
20#include "clang/Sema/EnterExpressionEvaluationContext.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
29using namespace clang;
30
31namespace {
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.
36class ResetStackCleanup
37 : public llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup,
38 const void> {
39public:
40 ResetStackCleanup(llvm::CrashRecoveryContext *Context, const void *Top)
41 : llvm::CrashRecoveryContextCleanupBase<ResetStackCleanup, const void>(
42 Context, Top) {}
43 void recoverResources() override {
44 llvm::RestorePrettyStackState(State: resource);
45 }
46};
47
48/// If a crash happens while the parser is active, an entry is printed for it.
49class PrettyStackTraceParserEntry : public llvm::PrettyStackTraceEntry {
50 const Parser &P;
51public:
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.
58void PrettyStackTraceParserEntry::print(raw_ostream &OS) const {
59 const Token &Tok = P.getCurToken();
60 if (Tok.is(K: 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, SM: 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(SL: Tok.getLocation(), Invalid: &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///
99void 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&: *S, PrintStats, SkipFunctionBodies);
112}
113
114void 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(a&: OldCollectStats, b&: S.CollectStats);
124
125 // Initialize the template instantiation observer chain.
126 // FIXME: See note on "finalize" below.
127 initialize(Callbacks&: S.TemplateInstCallbacks, TheSema: 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;
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 llvm::TimeTraceMetadata M;
156 if (llvm::isTimeTraceVerbose()) {
157 const SourceManager &SM = S.getSourceManager();
158 if (const auto *FE = SM.getFileEntryForID(FID: SM.getMainFileID()))
159 M.File = FE->tryGetRealPathName();
160 }
161 return M;
162 });
163 P.Initialize();
164 Parser::DeclGroupPtrTy ADecl;
165 Sema::ModuleImportState ImportState;
166 EnterExpressionEvaluationContext PotentiallyEvaluated(
167 S, Sema::ExpressionEvaluationContext::PotentiallyEvaluated);
168
169 for (bool AtEOF = P.ParseFirstTopLevelDecl(Result&: ADecl, ImportState); !AtEOF;
170 AtEOF = P.ParseTopLevelDecl(Result&: ADecl, ImportState)) {
171 // If we got a null return and something *was* parsed, ignore it. This
172 // is due to a top-level semicolon, an action override, or a parse error
173 // skipping something.
174 if (ADecl && !Consumer->HandleTopLevelDecl(D: ADecl.get()))
175 return;
176 }
177 }
178
179 // Process any TopLevelDecls generated by #pragma weak.
180 for (Decl *D : S.WeakTopLevelDecls())
181 Consumer->HandleTopLevelDecl(D: DeclGroupRef(D));
182
183 Consumer->HandleTranslationUnit(Ctx&: S.getASTContext());
184
185 // Finalize the template instantiation observer chain.
186 // FIXME: This (and init.) should be done in the Sema class, but because
187 // Sema does not have a reliable "Finalize" function (it has a
188 // destructor, but it is not guaranteed to be called ("-disable-free")).
189 // So, do the initialization above and do the finalization here:
190 finalize(Callbacks&: S.TemplateInstCallbacks, TheSema: S);
191
192 std::swap(a&: OldCollectStats, b&: S.CollectStats);
193 if (PrintStats) {
194 llvm::errs() << "\nSTATISTICS:\n";
195 if (HaveLexer) P.getActions().PrintStats();
196 S.getASTContext().PrintStats();
197 Decl::PrintStats();
198 Stmt::PrintStats();
199 Consumer->PrintStats();
200 }
201}
202