clang-tools 10.0.0

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