clang-tools 8.0.0

ComparisonInTempFailureRetryCheck.cpp
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1 //===--- ComparisonInTempFailureRetryCheck.cpp - clang-tidy----------------===//
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 #include "../utils/Matchers.h"
11 #include "ComparisonInTempFailureRetryCheck.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/ASTMatchers/ASTMatchFinder.h"
14 #include "clang/Lex/Lexer.h"
15
16 using namespace clang::ast_matchers;
17
18 namespace clang {
19 namespace tidy {
20 namespace android {
21
22 namespace {
23 AST_MATCHER(BinaryOperator, isRHSATempFailureRetryArg) {
24 if (!Node.getBeginLoc().isMacroID())
25 return false;
26
27 const SourceManager &SM = Finder->getASTContext().getSourceManager();
28 if (!SM.isMacroArgExpansion(Node.getRHS()->IgnoreParenCasts()->getBeginLoc()))
29 return false;
30
31 const LangOptions &Opts = Finder->getASTContext().getLangOpts();
32 SourceLocation LocStart = Node.getBeginLoc();
33 while (LocStart.isMacroID()) {
34 SourceLocation Invocation = SM.getImmediateMacroCallerLoc(LocStart);
35 Token Tok;
36 if (!Lexer::getRawToken(SM.getSpellingLoc(Invocation), Tok, SM, Opts,
37 /*IgnoreWhiteSpace=*/true)) {
38 if (Tok.getKind() == tok::raw_identifier &&
39 Tok.getRawIdentifier() == "TEMP_FAILURE_RETRY")
40 return true;
41 }
42
43 LocStart = Invocation;
44 }
45 return false;
46 }
47 } // namespace
48
49 void ComparisonInTempFailureRetryCheck::registerMatchers(MatchFinder *Finder) {
50 // Both glibc's and Bionic's TEMP_FAILURE_RETRY macros structurally look like:
51 //
52 // #define TEMP_FAILURE_RETRY(x) ({ \
53 // typeof(x) y; \
54 // do y = (x); \
55 // while (y == -1 && errno == EINTR); \
56 // y; \
57 // })
58 //
59 // (glibc uses `long int` instead of `typeof(x)` for the type of y).
60 //
61 // It's unclear how to walk up the AST from inside the expansion of `x`, and
62 // we need to not complain about things like TEMP_FAILURE_RETRY(foo(x == 1)),
63 // so we just match the assignment of `y = (x)` and inspect `x` from there.
64 Finder->addMatcher(
65 binaryOperator(
66 hasOperatorName("="),
67 hasRHS(ignoringParenCasts(
68 binaryOperator(matchers::isComparisonOperator()).bind("binop"))),
69 isRHSATempFailureRetryArg()),
70 this);
71 }
72
73 void ComparisonInTempFailureRetryCheck::check(
74 const MatchFinder::MatchResult &Result) {
75 const auto &BinOp = *Result.Nodes.getNodeAs<BinaryOperator>("binop");
76 diag(BinOp.getOperatorLoc(), "top-level comparison in TEMP_FAILURE_RETRY");
77
78 // FIXME: FixIts would be nice, but potentially nontrivial when nested macros
79 // happen, e.g. `TEMP_FAILURE_RETRY(IS_ZERO(foo()))`
80 }
81
82 } // namespace android
83 } // namespace tidy
84 } // namespace clang
clang::ast_matchers
Definition: AbseilMatcher.h:15
clang::tidy::matchers::AST_MATCHER
AST_MATCHER(BinaryOperator, isAssignmentOperator)
Definition: Matchers.h:20
ComparisonInTempFailureRetryCheck.h
Result
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
Definition: ClangdServer.cpp:60
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ChangeNamespace.cpp:18