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
ComparisonInTempFailureRetryCheck(StringRef Name,ClangTidyContext * Context)21 ComparisonInTempFailureRetryCheck::ComparisonInTempFailureRetryCheck(
22 StringRef Name, ClangTidyContext *Context)
23 : ClangTidyCheck(Name, Context),
24 RawRetryList(Options.get("RetryMacros", "TEMP_FAILURE_RETRY")) {
25 StringRef(RawRetryList).split(RetryMacros, ",", -1, false);
26 }
27
storeOptions(ClangTidyOptions::OptionMap & Opts)28 void ComparisonInTempFailureRetryCheck::storeOptions(
29 ClangTidyOptions::OptionMap &Opts) {
30 Options.store(Opts, "RetryMacros", RawRetryList);
31 }
32
registerMatchers(MatchFinder * Finder)33 void ComparisonInTempFailureRetryCheck::registerMatchers(MatchFinder *Finder) {
34 // Both glibc's and Bionic's TEMP_FAILURE_RETRY macros structurally look like:
35 //
36 // #define TEMP_FAILURE_RETRY(x) ({ \
37 // typeof(x) y; \
38 // do y = (x); \
39 // while (y == -1 && errno == EINTR); \
40 // y; \
41 // })
42 //
43 // (glibc uses `long int` instead of `typeof(x)` for the type of y).
44 //
45 // It's unclear how to walk up the AST from inside the expansion of `x`, and
46 // we need to not complain about things like TEMP_FAILURE_RETRY(foo(x == 1)),
47 // so we just match the assignment of `y = (x)` and inspect `x` from there.
48 Finder->addMatcher(
49 binaryOperator(hasOperatorName("="),
50 hasRHS(ignoringParenCasts(
51 binaryOperator(isComparisonOperator()).bind("inner"))))
52 .bind("outer"),
53 this);
54 }
55
check(const MatchFinder::MatchResult & Result)56 void ComparisonInTempFailureRetryCheck::check(
57 const MatchFinder::MatchResult &Result) {
58 StringRef RetryMacroName;
59 const auto &Node = *Result.Nodes.getNodeAs<BinaryOperator>("outer");
60 if (!Node.getBeginLoc().isMacroID())
61 return;
62
63 const SourceManager &SM = *Result.SourceManager;
64 if (!SM.isMacroArgExpansion(Node.getRHS()->IgnoreParenCasts()->getBeginLoc()))
65 return;
66
67 const LangOptions &Opts = Result.Context->getLangOpts();
68 SourceLocation LocStart = Node.getBeginLoc();
69 while (LocStart.isMacroID()) {
70 SourceLocation Invocation = SM.getImmediateMacroCallerLoc(LocStart);
71 Token Tok;
72 if (!Lexer::getRawToken(SM.getSpellingLoc(Invocation), Tok, SM, Opts,
73 /*IgnoreWhiteSpace=*/true)) {
74 if (Tok.getKind() == tok::raw_identifier &&
75 llvm::is_contained(RetryMacros, Tok.getRawIdentifier())) {
76 RetryMacroName = Tok.getRawIdentifier();
77 break;
78 }
79 }
80
81 LocStart = Invocation;
82 }
83 if (RetryMacroName.empty())
84 return;
85
86 const auto &Inner = *Result.Nodes.getNodeAs<BinaryOperator>("inner");
87 diag(Inner.getOperatorLoc(), "top-level comparison in %0") << RetryMacroName;
88
89 // FIXME: FixIts would be nice, but potentially nontrivial when nested macros
90 // happen, e.g. `TEMP_FAILURE_RETRY(IS_ZERO(foo()))`
91 }
92
93 } // namespace android
94 } // namespace tidy
95 } // namespace clang
96