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//===--- MisleadingIndentationCheck.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 "MisleadingIndentationCheck.h"
#include "../utils/LexerUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
using namespace clang::ast_matchers;
namespace clang::tidy::readability {
static const IfStmt *getPrecedingIf(const SourceManager &SM,
ASTContext *Context, const IfStmt *If) {
auto Parents = Context->getParents(*If);
if (Parents.size() != 1)
return nullptr;
if (const auto *PrecedingIf = Parents[0].get<IfStmt>()) {
SourceLocation PreviousElseLoc = PrecedingIf->getElseLoc();
if (SM.getExpansionLineNumber(PreviousElseLoc) ==
SM.getExpansionLineNumber(If->getIfLoc()))
return PrecedingIf;
}
return nullptr;
}
void MisleadingIndentationCheck::danglingElseCheck(const SourceManager &SM,
ASTContext *Context,
const IfStmt *If) {
SourceLocation IfLoc = If->getIfLoc();
SourceLocation ElseLoc = If->getElseLoc();
if (IfLoc.isMacroID() || ElseLoc.isMacroID())
return;
if (SM.getExpansionLineNumber(If->getThen()->getEndLoc()) ==
SM.getExpansionLineNumber(ElseLoc))
return;
// Find location of first 'if' in a 'if else if' chain.
for (const auto *PrecedingIf = getPrecedingIf(SM, Context, If); PrecedingIf;
PrecedingIf = getPrecedingIf(SM, Context, PrecedingIf))
IfLoc = PrecedingIf->getIfLoc();
if (SM.getExpansionColumnNumber(IfLoc) !=
SM.getExpansionColumnNumber(ElseLoc))
diag(ElseLoc, "different indentation for 'if' and corresponding 'else'");
}
static bool isAtStartOfLineIncludingEmptyMacro(SourceLocation NextLoc,
const SourceManager &SM,
const LangOptions &LangOpts) {
const SourceLocation BeforeLoc =
utils::lexer::getPreviousTokenAndStart(NextLoc, SM, LangOpts).second;
if (BeforeLoc.isInvalid())
return false;
return SM.getExpansionLineNumber(BeforeLoc) !=
SM.getExpansionLineNumber(NextLoc);
}
void MisleadingIndentationCheck::missingBracesCheck(
const SourceManager &SM, const CompoundStmt *CStmt,
const LangOptions &LangOpts) {
const static StringRef StmtNames[] = {"if", "for", "while"};
for (unsigned int I = 0; I < CStmt->size() - 1; I++) {
const Stmt *CurrentStmt = CStmt->body_begin()[I];
const Stmt *Inner = nullptr;
int StmtKind = 0;
if (const auto *CurrentIf = dyn_cast<IfStmt>(CurrentStmt)) {
StmtKind = 0;
Inner =
CurrentIf->getElse() ? CurrentIf->getElse() : CurrentIf->getThen();
} else if (const auto *CurrentFor = dyn_cast<ForStmt>(CurrentStmt)) {
StmtKind = 1;
Inner = CurrentFor->getBody();
} else if (const auto *CurrentWhile = dyn_cast<WhileStmt>(CurrentStmt)) {
StmtKind = 2;
Inner = CurrentWhile->getBody();
} else {
continue;
}
if (isa<CompoundStmt>(Inner))
continue;
SourceLocation InnerLoc = Inner->getBeginLoc();
SourceLocation OuterLoc = CurrentStmt->getBeginLoc();
if (InnerLoc.isInvalid() || InnerLoc.isMacroID() || OuterLoc.isInvalid() ||
OuterLoc.isMacroID())
continue;
if (SM.getExpansionLineNumber(InnerLoc) ==
SM.getExpansionLineNumber(OuterLoc))
continue;
const Stmt *NextStmt = CStmt->body_begin()[I + 1];
SourceLocation NextLoc = NextStmt->getBeginLoc();
if (NextLoc.isInvalid() || NextLoc.isMacroID())
continue;
if (!isAtStartOfLineIncludingEmptyMacro(NextLoc, SM, LangOpts))
continue;
if (SM.getExpansionColumnNumber(InnerLoc) ==
SM.getExpansionColumnNumber(NextLoc)) {
diag(NextLoc, "misleading indentation: statement is indented too deeply");
diag(OuterLoc, "did you mean this line to be inside this '%0'",
DiagnosticIDs::Note)
<< StmtNames[StmtKind];
}
}
}
void MisleadingIndentationCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
ifStmt(unless(hasThen(nullStmt())), hasElse(stmt())).bind("if"), this);
Finder->addMatcher(
compoundStmt(has(stmt(anyOf(ifStmt(), forStmt(), whileStmt()))))
.bind("compound"),
this);
}
void MisleadingIndentationCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *If = Result.Nodes.getNodeAs<IfStmt>("if"))
danglingElseCheck(*Result.SourceManager, Result.Context, If);
if (const auto *CStmt = Result.Nodes.getNodeAs<CompoundStmt>("compound"))
missingBracesCheck(*Result.SourceManager, CStmt,
Result.Context->getLangOpts());
}
} // namespace clang::tidy::readability
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