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| //===--- BracesAroundStatementsCheck.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 "BracesAroundStatementsCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace readability {
namespace {
tok::TokenKind getTokenKind(SourceLocation Loc, const SourceManager &SM,
const ASTContext *Context) {
Token Tok;
SourceLocation Beginning =
Lexer::GetBeginningOfToken(Loc, SM, Context->getLangOpts());
const bool Invalid =
Lexer::getRawToken(Beginning, Tok, SM, Context->getLangOpts());
assert(!Invalid && "Expected a valid token.");
if (Invalid)
return tok::NUM_TOKENS;
return Tok.getKind();
}
SourceLocation forwardSkipWhitespaceAndComments(SourceLocation Loc,
const SourceManager &SM,
const ASTContext *Context) {
assert(Loc.isValid());
for (;;) {
while (isWhitespace(*SM.getCharacterData(Loc)))
Loc = Loc.getLocWithOffset(1);
tok::TokenKind TokKind = getTokenKind(Loc, SM, Context);
if (TokKind == tok::NUM_TOKENS || TokKind != tok::comment)
return Loc;
// Fast-forward current token.
Loc = Lexer::getLocForEndOfToken(Loc, 0, SM, Context->getLangOpts());
}
}
SourceLocation findEndLocation(SourceLocation LastTokenLoc,
const SourceManager &SM,
const ASTContext *Context) {
SourceLocation Loc =
Lexer::GetBeginningOfToken(LastTokenLoc, SM, Context->getLangOpts());
// Loc points to the beginning of the last (non-comment non-ws) token
// before end or ';'.
assert(Loc.isValid());
bool SkipEndWhitespaceAndComments = true;
tok::TokenKind TokKind = getTokenKind(Loc, SM, Context);
if (TokKind == tok::NUM_TOKENS || TokKind == tok::semi ||
TokKind == tok::r_brace) {
// If we are at ";" or "}", we found the last token. We could use as well
// `if (isa<NullStmt>(S))`, but it wouldn't work for nested statements.
SkipEndWhitespaceAndComments = false;
}
Loc = Lexer::getLocForEndOfToken(Loc, 0, SM, Context->getLangOpts());
// Loc points past the last token before end or after ';'.
if (SkipEndWhitespaceAndComments) {
Loc = forwardSkipWhitespaceAndComments(Loc, SM, Context);
tok::TokenKind TokKind = getTokenKind(Loc, SM, Context);
if (TokKind == tok::semi)
Loc = Lexer::getLocForEndOfToken(Loc, 0, SM, Context->getLangOpts());
}
for (;;) {
assert(Loc.isValid());
while (isHorizontalWhitespace(*SM.getCharacterData(Loc))) {
Loc = Loc.getLocWithOffset(1);
}
if (isVerticalWhitespace(*SM.getCharacterData(Loc))) {
// EOL, insert brace before.
break;
}
tok::TokenKind TokKind = getTokenKind(Loc, SM, Context);
if (TokKind != tok::comment) {
// Non-comment token, insert brace before.
break;
}
SourceLocation TokEndLoc =
Lexer::getLocForEndOfToken(Loc, 0, SM, Context->getLangOpts());
SourceRange TokRange(Loc, TokEndLoc);
StringRef Comment = Lexer::getSourceText(
CharSourceRange::getTokenRange(TokRange), SM, Context->getLangOpts());
if (Comment.startswith("/*") && Comment.find('\n') != StringRef::npos) {
// Multi-line block comment, insert brace before.
break;
}
// else: Trailing comment, insert brace after the newline.
// Fast-forward current token.
Loc = TokEndLoc;
}
return Loc;
}
} // namespace
BracesAroundStatementsCheck::BracesAroundStatementsCheck(
StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
// Always add braces by default.
ShortStatementLines(Options.get("ShortStatementLines", 0U)) {}
void BracesAroundStatementsCheck::storeOptions(
ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "ShortStatementLines", ShortStatementLines);
}
void BracesAroundStatementsCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(ifStmt().bind("if"), this);
Finder->addMatcher(whileStmt().bind("while"), this);
Finder->addMatcher(doStmt().bind("do"), this);
Finder->addMatcher(forStmt().bind("for"), this);
Finder->addMatcher(cxxForRangeStmt().bind("for-range"), this);
}
void BracesAroundStatementsCheck::check(
const MatchFinder::MatchResult &Result) {
const SourceManager &SM = *Result.SourceManager;
const ASTContext *Context = Result.Context;
// Get location of closing parenthesis or 'do' to insert opening brace.
if (auto S = Result.Nodes.getNodeAs<ForStmt>("for")) {
checkStmt(Result, S->getBody(), S->getRParenLoc());
} else if (auto S = Result.Nodes.getNodeAs<CXXForRangeStmt>("for-range")) {
checkStmt(Result, S->getBody(), S->getRParenLoc());
} else if (auto S = Result.Nodes.getNodeAs<DoStmt>("do")) {
checkStmt(Result, S->getBody(), S->getDoLoc(), S->getWhileLoc());
} else if (auto S = Result.Nodes.getNodeAs<WhileStmt>("while")) {
SourceLocation StartLoc = findRParenLoc(S, SM, Context);
if (StartLoc.isInvalid())
return;
checkStmt(Result, S->getBody(), StartLoc);
} else if (auto S = Result.Nodes.getNodeAs<IfStmt>("if")) {
SourceLocation StartLoc = findRParenLoc(S, SM, Context);
if (StartLoc.isInvalid())
return;
if (ForceBracesStmts.erase(S))
ForceBracesStmts.insert(S->getThen());
bool BracedIf = checkStmt(Result, S->getThen(), StartLoc, S->getElseLoc());
const Stmt *Else = S->getElse();
if (Else && BracedIf)
ForceBracesStmts.insert(Else);
if (Else && !isa<IfStmt>(Else)) {
// Omit 'else if' statements here, they will be handled directly.
checkStmt(Result, Else, S->getElseLoc());
}
} else {
llvm_unreachable("Invalid match");
}
}
/// Find location of right parenthesis closing condition.
template <typename IfOrWhileStmt>
SourceLocation
BracesAroundStatementsCheck::findRParenLoc(const IfOrWhileStmt *S,
const SourceManager &SM,
const ASTContext *Context) {
// Skip macros.
if (S->getBeginLoc().isMacroID())
return SourceLocation();
SourceLocation CondEndLoc = S->getCond()->getEndLoc();
if (const DeclStmt *CondVar = S->getConditionVariableDeclStmt())
CondEndLoc = CondVar->getEndLoc();
if (!CondEndLoc.isValid()) {
return SourceLocation();
}
SourceLocation PastCondEndLoc =
Lexer::getLocForEndOfToken(CondEndLoc, 0, SM, Context->getLangOpts());
if (PastCondEndLoc.isInvalid())
return SourceLocation();
SourceLocation RParenLoc =
forwardSkipWhitespaceAndComments(PastCondEndLoc, SM, Context);
if (RParenLoc.isInvalid())
return SourceLocation();
tok::TokenKind TokKind = getTokenKind(RParenLoc, SM, Context);
if (TokKind != tok::r_paren)
return SourceLocation();
return RParenLoc;
}
/// Determine if the statement needs braces around it, and add them if it does.
/// Returns true if braces where added.
bool BracesAroundStatementsCheck::checkStmt(
const MatchFinder::MatchResult &Result, const Stmt *S,
SourceLocation InitialLoc, SourceLocation EndLocHint) {
// 1) If there's a corresponding "else" or "while", the check inserts "} "
// right before that token.
// 2) If there's a multi-line block comment starting on the same line after
// the location we're inserting the closing brace at, or there's a non-comment
// token, the check inserts "\n}" right before that token.
// 3) Otherwise the check finds the end of line (possibly after some block or
// line comments) and inserts "\n}" right before that EOL.
if (!S || isa<CompoundStmt>(S)) {
// Already inside braces.
return false;
}
if (!InitialLoc.isValid())
return false;
const SourceManager &SM = *Result.SourceManager;
const ASTContext *Context = Result.Context;
// Treat macros.
CharSourceRange FileRange = Lexer::makeFileCharRange(
CharSourceRange::getTokenRange(S->getSourceRange()), SM,
Context->getLangOpts());
if (FileRange.isInvalid())
return false;
// Convert InitialLoc to file location, if it's on the same macro expansion
// level as the start of the statement. We also need file locations for
// Lexer::getLocForEndOfToken working properly.
InitialLoc = Lexer::makeFileCharRange(
CharSourceRange::getCharRange(InitialLoc, S->getBeginLoc()),
SM, Context->getLangOpts())
.getBegin();
if (InitialLoc.isInvalid())
return false;
SourceLocation StartLoc =
Lexer::getLocForEndOfToken(InitialLoc, 0, SM, Context->getLangOpts());
// StartLoc points at the location of the opening brace to be inserted.
SourceLocation EndLoc;
std::string ClosingInsertion;
if (EndLocHint.isValid()) {
EndLoc = EndLocHint;
ClosingInsertion = "} ";
} else {
const auto FREnd = FileRange.getEnd().getLocWithOffset(-1);
EndLoc = findEndLocation(FREnd, SM, Context);
ClosingInsertion = "\n}";
}
assert(StartLoc.isValid());
assert(EndLoc.isValid());
// Don't require braces for statements spanning less than certain number of
// lines.
if (ShortStatementLines && !ForceBracesStmts.erase(S)) {
unsigned StartLine = SM.getSpellingLineNumber(StartLoc);
unsigned EndLine = SM.getSpellingLineNumber(EndLoc);
if (EndLine - StartLine < ShortStatementLines)
return false;
}
auto Diag = diag(StartLoc, "statement should be inside braces");
Diag << FixItHint::CreateInsertion(StartLoc, " {")
<< FixItHint::CreateInsertion(EndLoc, ClosingInsertion);
return true;
}
void BracesAroundStatementsCheck::onEndOfTranslationUnit() {
ForceBracesStmts.clear();
}
} // namespace readability
} // namespace tidy
} // namespace clang
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