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//===--- MultipleStatementMacroCheck.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 "MultipleStatementMacroCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace bugprone {
namespace {
AST_MATCHER(Expr, isInMacro) { return Node.getBeginLoc().isMacroID(); }
/// \brief Find the next statement after `S`.
const Stmt *nextStmt(const MatchFinder::MatchResult &Result, const Stmt *S) {
auto Parents = Result.Context->getParents(*S);
if (Parents.empty())
return nullptr;
const auto *Parent = Parents[0].get<Stmt>();
if (!Parent)
return nullptr;
const Stmt *Prev = nullptr;
for (const Stmt *Child : Parent->children()) {
if (Prev == S)
return Child;
Prev = Child;
}
return nextStmt(Result, Parent);
}
using ExpansionRanges = std::vector<SourceRange>;
/// \bried Get all the macro expansion ranges related to `Loc`.
///
/// The result is ordered from most inner to most outer.
ExpansionRanges getExpansionRanges(SourceLocation Loc,
const MatchFinder::MatchResult &Result) {
ExpansionRanges Locs;
while (Loc.isMacroID()) {
Locs.push_back(
Result.SourceManager->getImmediateExpansionRange(Loc).getAsRange());
Loc = Locs.back().getBegin();
}
return Locs;
}
} // namespace
void MultipleStatementMacroCheck::registerMatchers(MatchFinder *Finder) {
const auto Inner = expr(isInMacro(), unless(compoundStmt())).bind("inner");
Finder->addMatcher(
stmt(anyOf(ifStmt(hasThen(Inner)), ifStmt(hasElse(Inner)).bind("else"),
whileStmt(hasBody(Inner)), forStmt(hasBody(Inner))))
.bind("outer"),
this);
}
void MultipleStatementMacroCheck::check(
const MatchFinder::MatchResult &Result) {
const auto *Inner = Result.Nodes.getNodeAs<Expr>("inner");
const auto *Outer = Result.Nodes.getNodeAs<Stmt>("outer");
const auto *Next = nextStmt(Result, Outer);
if (!Next)
return;
SourceLocation OuterLoc = Outer->getBeginLoc();
if (Result.Nodes.getNodeAs<Stmt>("else"))
OuterLoc = cast<IfStmt>(Outer)->getElseLoc();
auto InnerRanges = getExpansionRanges(Inner->getBeginLoc(), Result);
auto OuterRanges = getExpansionRanges(OuterLoc, Result);
auto NextRanges = getExpansionRanges(Next->getBeginLoc(), Result);
// Remove all the common ranges, starting from the top (the last ones in the
// list).
while (!InnerRanges.empty() && !OuterRanges.empty() && !NextRanges.empty() &&
InnerRanges.back() == OuterRanges.back() &&
InnerRanges.back() == NextRanges.back()) {
InnerRanges.pop_back();
OuterRanges.pop_back();
NextRanges.pop_back();
}
// Inner and Next must have at least one more macro that Outer doesn't have,
// and that range must be common to both.
if (InnerRanges.empty() || NextRanges.empty() ||
InnerRanges.back() != NextRanges.back())
return;
diag(InnerRanges.back().getBegin(), "multiple statement macro used without "
"braces; some statements will be "
"unconditionally executed");
}
} // namespace bugprone
} // namespace tidy
} // namespace clang
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