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//===--- UppercaseLiteralSuffixCheck.cpp - clang-tidy ---------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "UppercaseLiteralSuffixCheck.h"
#include "../utils/ASTUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallString.h"
#include <cctype>
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace readability {
namespace {
struct IntegerLiteralCheck {
using type = clang::IntegerLiteral;
static constexpr llvm::StringLiteral Name = llvm::StringLiteral("integer");
// What should be skipped before looking for the Suffixes? (Nothing here.)
static constexpr llvm::StringLiteral SkipFirst = llvm::StringLiteral("");
// Suffix can only consist of 'u' and 'l' chars, and can be a complex number
// ('i', 'j'). In MS compatibility mode, suffixes like i32 are supported.
static constexpr llvm::StringLiteral Suffixes =
constexpr llvm::StringLiteral IntegerLiteralCheck::Name;
constexpr llvm::StringLiteral IntegerLiteralCheck::SkipFirst;
constexpr llvm::StringLiteral IntegerLiteralCheck::Suffixes;
struct FloatingLiteralCheck {
using type = clang::FloatingLiteral;
static constexpr llvm::StringLiteral Name =
llvm::StringLiteral("floating point");
// C++17 introduced hexadecimal floating-point literals, and 'f' is both a
// valid hexadecimal digit in a hex float literal and a valid floating-point
// literal suffix.
// So we can't just "skip to the chars that can be in the suffix".
// Since the exponent ('p'/'P') is mandatory for hexadecimal floating-point
// literals, we first skip everything before the exponent.
static constexpr llvm::StringLiteral SkipFirst = llvm::StringLiteral("pP");
// Suffix can only consist of 'f', 'l', "f16", 'h', 'q' chars,
// and can be a complex number ('i', 'j').
static constexpr llvm::StringLiteral Suffixes =
constexpr llvm::StringLiteral FloatingLiteralCheck::Name;
constexpr llvm::StringLiteral FloatingLiteralCheck::SkipFirst;
constexpr llvm::StringLiteral FloatingLiteralCheck::Suffixes;
struct NewSuffix {
SourceRange LiteralLocation;
StringRef OldSuffix;
llvm::Optional<FixItHint> FixIt;
llvm::Optional<SourceLocation> getMacroAwareLocation(SourceLocation Loc,
const SourceManager &SM) {
// Do nothing if the provided location is invalid.
if (Loc.isInvalid())
return llvm::None;
// Look where the location was *actually* written.
SourceLocation SpellingLoc = SM.getSpellingLoc(Loc);
if (SpellingLoc.isInvalid())
return llvm::None;
return SpellingLoc;
llvm::Optional<SourceRange> getMacroAwareSourceRange(SourceRange Loc,
const SourceManager &SM) {
llvm::Optional<SourceLocation> Begin =
getMacroAwareLocation(Loc.getBegin(), SM);
llvm::Optional<SourceLocation> End = getMacroAwareLocation(Loc.getEnd(), SM);
if (!Begin || !End)
return llvm::None;
return SourceRange(*Begin, *End);
getNewSuffix(llvm::StringRef OldSuffix,
const std::vector<std::string> &NewSuffixes) {
// If there is no config, just uppercase the entirety of the suffix.
if (NewSuffixes.empty())
return OldSuffix.upper();
// Else, find matching suffix, case-*insensitive*ly.
auto NewSuffix = llvm::find_if(
NewSuffixes, [OldSuffix](const std::string &PotentialNewSuffix) {
return OldSuffix.equals_insensitive(PotentialNewSuffix);
// Have a match, return it.
if (NewSuffix != NewSuffixes.end())
return *NewSuffix;
// Nope, I guess we have to keep it as-is.
return llvm::None;
template <typename LiteralType>
shouldReplaceLiteralSuffix(const Expr &Literal,
const std::vector<std::string> &NewSuffixes,
const SourceManager &SM, const LangOptions &LO) {
NewSuffix ReplacementDsc;
const auto &L = cast<typename LiteralType::type>(Literal);
// The naive location of the literal. Is always valid.
ReplacementDsc.LiteralLocation = L.getSourceRange();
// Was this literal fully spelled or is it a product of macro expansion?
bool RangeCanBeFixed =
utils::rangeCanBeFixed(ReplacementDsc.LiteralLocation, &SM);
// The literal may have macro expansion, we need the final expanded src range.
llvm::Optional<SourceRange> Range =
getMacroAwareSourceRange(ReplacementDsc.LiteralLocation, SM);
if (!Range)
return llvm::None;
if (RangeCanBeFixed)
ReplacementDsc.LiteralLocation = *Range;
// Else keep the naive literal location!
// Get the whole literal from the source buffer.
bool Invalid;
const StringRef LiteralSourceText = Lexer::getSourceText(
CharSourceRange::getTokenRange(*Range), SM, LO, &Invalid);
assert(!Invalid && "Failed to retrieve the source text.");
// Make sure the first character is actually a digit, instead of
// something else, like a non-type template parameter.
if (!std::isdigit(static_cast<unsigned char>(LiteralSourceText.front())))
return llvm::None;
size_t Skip = 0;
// Do we need to ignore something before actually looking for the suffix?
if (!LiteralType::SkipFirst.empty()) {
// E.g. we can't look for 'f' suffix in hexadecimal floating-point literals
// until after we skip to the exponent (which is mandatory there),
// because hex-digit-sequence may contain 'f'.
Skip = LiteralSourceText.find_first_of(LiteralType::SkipFirst);
// We could be in non-hexadecimal floating-point literal, with no exponent.
if (Skip == StringRef::npos)
Skip = 0;
// Find the beginning of the suffix by looking for the first char that is
// one of these chars that can be in the suffix, potentially starting looking
// in the exponent, if we are skipping hex-digit-sequence.
Skip = LiteralSourceText.find_first_of(LiteralType::Suffixes, /*From=*/Skip);
// We can't check whether the *Literal has any suffix or not without actually
// looking for the suffix. So it is totally possible that there is no suffix.
if (Skip == StringRef::npos)
return llvm::None;
// Move the cursor in the source range to the beginning of the suffix.
// And in our textual representation too.
ReplacementDsc.OldSuffix = LiteralSourceText.drop_front(Skip);
assert(!ReplacementDsc.OldSuffix.empty() &&
"We still should have some chars left.");
// And get the replacement suffix.
llvm::Optional<std::string> NewSuffix =
getNewSuffix(ReplacementDsc.OldSuffix, NewSuffixes);
if (!NewSuffix || ReplacementDsc.OldSuffix == *NewSuffix)
return llvm::None; // The suffix was already the way it should be.
if (RangeCanBeFixed)
ReplacementDsc.FixIt = FixItHint::CreateReplacement(*Range, *NewSuffix);
return ReplacementDsc;
} // namespace
StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
utils::options::parseStringList(Options.get("NewSuffixes", ""))),
IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {}
void UppercaseLiteralSuffixCheck::storeOptions(
ClangTidyOptions::OptionMap &Opts) {, "NewSuffixes",
utils::options::serializeStringList(NewSuffixes));, "IgnoreMacros", IgnoreMacros);
void UppercaseLiteralSuffixCheck::registerMatchers(MatchFinder *Finder) {
// Sadly, we can't check whether the literal has suffix or not.
// E.g. i32 suffix still results in 'BuiltinType::Kind::Int'.
// And such an info is not stored in the *Literal itself.
template <typename LiteralType>
bool UppercaseLiteralSuffixCheck::checkBoundMatch(
const MatchFinder::MatchResult &Result) {
const auto *Literal =
Result.Nodes.getNodeAs<typename LiteralType::type>(LiteralType::Name);
if (!Literal)
return false;
// We won't *always* want to diagnose.
// We might have a suffix that is already uppercase.
if (auto Details = shouldReplaceLiteralSuffix<LiteralType>(
*Literal, NewSuffixes, *Result.SourceManager, getLangOpts())) {
if (Details->LiteralLocation.getBegin().isMacroID() && IgnoreMacros)
return true;
auto Complaint = diag(Details->LiteralLocation.getBegin(),
"%0 literal has suffix '%1', which is not uppercase")
<< LiteralType::Name << Details->OldSuffix;
if (Details->FixIt) // Similarly, a fix-it is not always possible.
Complaint << *(Details->FixIt);
return true;
void UppercaseLiteralSuffixCheck::check(
const MatchFinder::MatchResult &Result) {
if (checkBoundMatch<IntegerLiteralCheck>(Result))
return; // If it *was* IntegerLiteral, don't check for FloatingLiteral.
} // namespace readability
} // namespace tidy
} // namespace clang