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[clang-tidy] Add fix-its to readability-avoid-return-with-void-value check #81420

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Merged
merged 5 commits into from
Apr 7, 2024
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[clang-tidy] Add fix-its to readability-avoid-return-with-void-value check #81420

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4b7d4a4
[clang-tidy] Add fix-its to `avoid-return-with-void-value` check
SimplyDanny Feb 11, 2024
ebeefa6
Omit blocks for single statements
SimplyDanny Feb 20, 2024
3d36f81
Use findNextTerminator
SimplyDanny Feb 20, 2024
1571389
Reuse logic from existing check to insert braces around statements
SimplyDanny Mar 29, 2024
91db7ba
Avoid blank return when statement is last in a function body
SimplyDanny Mar 30, 2024
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44 changes: 33 additions & 11 deletions clang-tools-extra/clang-tidy/readability/AvoidReturnWithVoidValueCheck.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7,19 +7,18 @@
//===----------------------------------------------------------------------===//

#include "AvoidReturnWithVoidValueCheck.h"
#include "clang/AST/Stmt.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "../utils/BracesAroundStatement.h"
#include "../utils/LexerUtils.h"

using namespace clang::ast_matchers;

namespace clang::tidy::readability {

static constexpr auto IgnoreMacrosName = "IgnoreMacros";
static constexpr auto IgnoreMacrosDefault = true;
static constexpr char IgnoreMacrosName[] = "IgnoreMacros";
static const bool IgnoreMacrosDefault = true;

static constexpr auto StrictModeName = "StrictMode";
static constexpr auto StrictModeDefault = true;
static constexpr char StrictModeName[] = "StrictMode";
static const bool StrictModeDefault = true;

AvoidReturnWithVoidValueCheck::AvoidReturnWithVoidValueCheck(
StringRef Name, ClangTidyContext *Context)
Expand All @@ -32,7 +31,10 @@ void AvoidReturnWithVoidValueCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
returnStmt(
hasReturnValue(allOf(hasType(voidType()), unless(initListExpr()))),
optionally(hasParent(compoundStmt().bind("compound_parent"))))
optionally(hasParent(
compoundStmt(
optionally(hasParent(functionDecl().bind("function_parent"))))
.bind("compound_parent"))))
.bind("void_return"),
this);
}
Expand All @@ -42,10 +44,30 @@ void AvoidReturnWithVoidValueCheck::check(
const auto *VoidReturn = Result.Nodes.getNodeAs<ReturnStmt>("void_return");
if (IgnoreMacros && VoidReturn->getBeginLoc().isMacroID())
return;
if (!StrictMode && !Result.Nodes.getNodeAs<CompoundStmt>("compound_parent"))
const auto *SurroundingBlock =
Result.Nodes.getNodeAs<CompoundStmt>("compound_parent");
if (!StrictMode && !SurroundingBlock)
return;
diag(VoidReturn->getBeginLoc(), "return statement within a void function "
"should not have a specified return value");
DiagnosticBuilder Diag = diag(VoidReturn->getBeginLoc(),
"return statement within a void function "
"should not have a specified return value");
const SourceLocation SemicolonPos = utils::lexer::findNextTerminator(
VoidReturn->getEndLoc(), *Result.SourceManager, getLangOpts());
if (SemicolonPos.isInvalid())
return;
if (!SurroundingBlock) {
const auto BraceInsertionHints = utils::getBraceInsertionsHints(
VoidReturn, getLangOpts(), *Result.SourceManager,
VoidReturn->getBeginLoc());
if (BraceInsertionHints)
Diag << BraceInsertionHints.openingBraceFixIt()
<< BraceInsertionHints.closingBraceFixIt();
}
Diag << FixItHint::CreateRemoval(VoidReturn->getReturnLoc());
if (!Result.Nodes.getNodeAs<FunctionDecl>("function_parent") ||
SurroundingBlock->body_back() != VoidReturn)
Comment on lines +58 to +68
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Hi @SimplyDanny, we are getting a static verifier hit on this code now since there is a nullptr check of SurroundingBlock followed by a use of SurroundingBlock without a check.

It seems when there is a function parent SurroundingBlock won't be a nullptr since it will be set to the function's CompoundStmt, but that's not completely obvious to the reader of the code.

You might consider adding an assert to make it clear for anyone modifying in the future. Maybe:

const auto *FunctionParent =                                       
    Result.Nodes.getNodeAs<FunctionDecl>("function_parent");       
assert((!FunctionParent || SurroundingBlock) &&                    
       "missing surrounding block when function parent");          
if (!FunctionParent || SurroundingBlock->body_back() != VoidReturn)

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Addressing this in #90173.

Diag << FixItHint::CreateInsertion(SemicolonPos.getLocWithOffset(1),
" return;", true);
}

void AvoidReturnWithVoidValueCheck::storeOptions(
Expand Down
157 changes: 25 additions & 132 deletions clang-tools-extra/clang-tidy/readability/BracesAroundStatementsCheck.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//

#include "BracesAroundStatementsCheck.h"
#include "../utils/BracesAroundStatement.h"
#include "../utils/LexerUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchers.h"
Expand All @@ -17,12 +18,10 @@ using namespace clang::ast_matchers;
namespace clang::tidy::readability {

static tok::TokenKind getTokenKind(SourceLocation Loc, const SourceManager &SM,
const ASTContext *Context) {
const LangOptions &LangOpts) {
Token Tok;
SourceLocation Beginning =
Lexer::GetBeginningOfToken(Loc, SM, Context->getLangOpts());
const bool Invalid =
Lexer::getRawToken(Beginning, Tok, SM, Context->getLangOpts());
SourceLocation Beginning = Lexer::GetBeginningOfToken(Loc, SM, LangOpts);
const bool Invalid = Lexer::getRawToken(Beginning, Tok, SM, LangOpts);
assert(!Invalid && "Expected a valid token.");

if (Invalid)
Expand All @@ -33,64 +32,21 @@ static tok::TokenKind getTokenKind(SourceLocation Loc, const SourceManager &SM,

static SourceLocation
forwardSkipWhitespaceAndComments(SourceLocation Loc, const SourceManager &SM,
const ASTContext *Context) {
const LangOptions &LangOpts) {
assert(Loc.isValid());
for (;;) {
while (isWhitespace(*SM.getCharacterData(Loc)))
Loc = Loc.getLocWithOffset(1);

tok::TokenKind TokKind = getTokenKind(Loc, SM, Context);
tok::TokenKind TokKind = getTokenKind(Loc, SM, LangOpts);
if (TokKind != tok::comment)
return Loc;

// Fast-forward current token.
Loc = Lexer::getLocForEndOfToken(Loc, 0, SM, Context->getLangOpts());
Loc = Lexer::getLocForEndOfToken(Loc, 0, SM, LangOpts);
}
}

static SourceLocation findEndLocation(const Stmt &S, const SourceManager &SM,
const ASTContext *Context) {
SourceLocation Loc =
utils::lexer::getUnifiedEndLoc(S, SM, Context->getLangOpts());
if (!Loc.isValid())
return Loc;

// Start searching right after S.
Loc = Loc.getLocWithOffset(1);

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.starts_with("/*") && Comment.contains('\n')) {
// Multi-line block comment, insert brace before.
break;
}
// else: Trailing comment, insert brace after the newline.

// Fast-forward current token.
Loc = TokEndLoc;
}
return Loc;
}

BracesAroundStatementsCheck::BracesAroundStatementsCheck(
StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
Expand Down Expand Up @@ -124,7 +80,7 @@ void BracesAroundStatementsCheck::check(
} else if (const auto *S = Result.Nodes.getNodeAs<DoStmt>("do")) {
checkStmt(Result, S->getBody(), S->getDoLoc(), S->getWhileLoc());
} else if (const auto *S = Result.Nodes.getNodeAs<WhileStmt>("while")) {
SourceLocation StartLoc = findRParenLoc(S, SM, Context);
SourceLocation StartLoc = findRParenLoc(S, SM, Context->getLangOpts());
if (StartLoc.isInvalid())
return;
checkStmt(Result, S->getBody(), StartLoc);
Expand All @@ -133,7 +89,7 @@ void BracesAroundStatementsCheck::check(
if (S->isConsteval())
return;

SourceLocation StartLoc = findRParenLoc(S, SM, Context);
SourceLocation StartLoc = findRParenLoc(S, SM, Context->getLangOpts());
if (StartLoc.isInvalid())
return;
if (ForceBracesStmts.erase(S))
Expand All @@ -156,7 +112,7 @@ template <typename IfOrWhileStmt>
SourceLocation
BracesAroundStatementsCheck::findRParenLoc(const IfOrWhileStmt *S,
const SourceManager &SM,
const ASTContext *Context) {
const LangOptions &LangOpts) {
// Skip macros.
if (S->getBeginLoc().isMacroID())
return {};
Expand All @@ -170,14 +126,14 @@ BracesAroundStatementsCheck::findRParenLoc(const IfOrWhileStmt *S,
}

SourceLocation PastCondEndLoc =
Lexer::getLocForEndOfToken(CondEndLoc, 0, SM, Context->getLangOpts());
Lexer::getLocForEndOfToken(CondEndLoc, 0, SM, LangOpts);
if (PastCondEndLoc.isInvalid())
return {};
SourceLocation RParenLoc =
forwardSkipWhitespaceAndComments(PastCondEndLoc, SM, Context);
forwardSkipWhitespaceAndComments(PastCondEndLoc, SM, LangOpts);
if (RParenLoc.isInvalid())
return {};
tok::TokenKind TokKind = getTokenKind(RParenLoc, SM, Context);
tok::TokenKind TokKind = getTokenKind(RParenLoc, SM, LangOpts);
if (TokKind != tok::r_paren)
return {};
return RParenLoc;
Expand All @@ -188,86 +144,23 @@ BracesAroundStatementsCheck::findRParenLoc(const IfOrWhileStmt *S,
bool BracesAroundStatementsCheck::checkStmt(
const MatchFinder::MatchResult &Result, const Stmt *S,
SourceLocation StartLoc, SourceLocation EndLocHint) {

while (const auto *AS = dyn_cast<AttributedStmt>(S))
S = AS->getSubStmt();

const SourceManager &SM = *Result.SourceManager;
const ASTContext *Context = Result.Context;

// 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;
}

// When TreeTransform, Stmt in constexpr IfStmt will be transform to NullStmt.
// This NullStmt can be detected according to beginning token.
const SourceLocation StmtBeginLoc = S->getBeginLoc();
if (isa<NullStmt>(S) && StmtBeginLoc.isValid() &&
getTokenKind(StmtBeginLoc, SM, Context) == tok::l_brace)
return false;

if (StartLoc.isInvalid())
return false;

// Convert StartLoc 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.
StartLoc = Lexer::makeFileCharRange(
CharSourceRange::getCharRange(StartLoc, S->getBeginLoc()), SM,
Context->getLangOpts())
.getBegin();
if (StartLoc.isInvalid())
return false;
StartLoc =
Lexer::getLocForEndOfToken(StartLoc, 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 {
EndLoc = findEndLocation(*S, SM, Context);
ClosingInsertion = "\n}";
}

assert(StartLoc.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)
const auto BraceInsertionHints = utils::getBraceInsertionsHints(
S, Result.Context->getLangOpts(), *Result.SourceManager, StartLoc,
EndLocHint);
if (BraceInsertionHints) {
if (ShortStatementLines && !ForceBracesStmts.erase(S) &&
BraceInsertionHints.resultingCompoundLineExtent(*Result.SourceManager) <
ShortStatementLines)
return false;
auto Diag = diag(BraceInsertionHints.DiagnosticPos,
"statement should be inside braces");
if (BraceInsertionHints.offersFixIts())
Diag << BraceInsertionHints.openingBraceFixIt()
<< BraceInsertionHints.closingBraceFixIt();
}

auto Diag = diag(StartLoc, "statement should be inside braces");

// Change only if StartLoc and EndLoc are on the same macro expansion level.
// This will also catch invalid EndLoc.
// Example: LLVM_DEBUG( for(...) do_something() );
// In this case fix-it cannot be provided as the semicolon which is not
// visible here is part of the macro. Adding braces here would require adding
// another semicolon.
if (Lexer::makeFileCharRange(
CharSourceRange::getTokenRange(SourceRange(
SM.getSpellingLoc(StartLoc), SM.getSpellingLoc(EndLoc))),
SM, Context->getLangOpts())
.isInvalid())
return false;

Diag << FixItHint::CreateInsertion(StartLoc, " {")
<< FixItHint::CreateInsertion(EndLoc, ClosingInsertion);
return true;
}

Expand Down
2 changes: 1 addition & 1 deletion clang-tools-extra/clang-tidy/readability/BracesAroundStatementsCheck.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,7 @@ class BracesAroundStatementsCheck : public ClangTidyCheck {
SourceLocation EndLocHint = SourceLocation());
template <typename IfOrWhileStmt>
SourceLocation findRParenLoc(const IfOrWhileStmt *S, const SourceManager &SM,
const ASTContext *Context);
const LangOptions &LangOpts);
std::optional<TraversalKind> getCheckTraversalKind() const override {
return TK_IgnoreUnlessSpelledInSource;
}
Expand Down
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