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//===--- ComparisonInTempFailureRetryCheck.cpp - clang-tidy----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "../utils/Matchers.h"
#include "ComparisonInTempFailureRetryCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace android {
ComparisonInTempFailureRetryCheck::ComparisonInTempFailureRetryCheck(
StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
RawRetryList(Options.get("RetryMacros", "TEMP_FAILURE_RETRY")) {
StringRef(RawRetryList).split(RetryMacros, ",", -1, false);
}
void ComparisonInTempFailureRetryCheck::storeOptions(
ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "RetryMacros", RawRetryList);
}
void ComparisonInTempFailureRetryCheck::registerMatchers(MatchFinder *Finder) {
// Both glibc's and Bionic's TEMP_FAILURE_RETRY macros structurally look like:
//
// #define TEMP_FAILURE_RETRY(x) ({ \
// typeof(x) y; \
// do y = (x); \
// while (y == -1 && errno == EINTR); \
// y; \
// })
//
// (glibc uses `long int` instead of `typeof(x)` for the type of y).
//
// It's unclear how to walk up the AST from inside the expansion of `x`, and
// we need to not complain about things like TEMP_FAILURE_RETRY(foo(x == 1)),
// so we just match the assignment of `y = (x)` and inspect `x` from there.
Finder->addMatcher(
binaryOperator(hasOperatorName("="),
hasRHS(ignoringParenCasts(
binaryOperator(isComparisonOperator()).bind("inner"))))
.bind("outer"),
this);
}
void ComparisonInTempFailureRetryCheck::check(
const MatchFinder::MatchResult &Result) {
StringRef RetryMacroName;
const auto &Node = *Result.Nodes.getNodeAs<BinaryOperator>("outer");
if (!Node.getBeginLoc().isMacroID())
return;
const SourceManager &SM = *Result.SourceManager;
if (!SM.isMacroArgExpansion(Node.getRHS()->IgnoreParenCasts()->getBeginLoc()))
return;
const LangOptions &Opts = Result.Context->getLangOpts();
SourceLocation LocStart = Node.getBeginLoc();
while (LocStart.isMacroID()) {
SourceLocation Invocation = SM.getImmediateMacroCallerLoc(LocStart);
Token Tok;
if (!Lexer::getRawToken(SM.getSpellingLoc(Invocation), Tok, SM, Opts,
/*IgnoreWhiteSpace=*/true)) {
if (Tok.getKind() == tok::raw_identifier &&
llvm::is_contained(RetryMacros, Tok.getRawIdentifier())) {
RetryMacroName = Tok.getRawIdentifier();
break;
}
}
LocStart = Invocation;
}
if (RetryMacroName.empty())
return;
const auto &Inner = *Result.Nodes.getNodeAs<BinaryOperator>("inner");
diag(Inner.getOperatorLoc(), "top-level comparison in %0") << RetryMacroName;
// FIXME: FixIts would be nice, but potentially nontrivial when nested macros
// happen, e.g. `TEMP_FAILURE_RETRY(IS_ZERO(foo()))`
}
} // namespace android
} // namespace tidy
} // namespace clang
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