clang-tidy: write a lint for charptr_cast

This lets us ensure that nobody is putting in new reinterpret_cast
instances where they could safely use charptr_cast instead.

Change-Id: I6358a3934c8133c7150042635843bdbb6b9218d4
This commit is contained in:
Jade Lovelace 2024-08-04 22:02:53 -07:00
parent a85c4ce535
commit a5f0954c29
5 changed files with 88 additions and 1 deletions

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@ -22,6 +22,13 @@ Checks:
- cppcoreguidelines-avoid-capturing-lambda-coroutines
# crimes must be appropriately declared as crimes
- cppcoreguidelines-pro-type-cstyle-cast
- lix-*
# This can not yet be applied to Lix itself since we need to do source
# reorganization so that lix/ include paths work.
- -lix-fixincludes
# This lint is included as an example, but the lib function it replaces is
# already gone.
- -lix-hasprefixsuffix
CheckOptions:

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@ -0,0 +1,45 @@
#include "CharPtrCast.hh"
#include <clang/AST/ExprCXX.h>
#include <clang/Basic/Diagnostic.h>
#include <clang/Tooling/Transformer/SourceCode.h>
namespace nix::clang_tidy {
using namespace clang::ast_matchers;
using namespace clang;
void CharPtrCastCheck::registerMatchers(ast_matchers::MatchFinder *Finder) {
Finder->addMatcher(
traverse(clang::TK_IgnoreUnlessSpelledInSource,
cxxReinterpretCastExpr(allOf(
hasDestinationType(qualType(pointsTo(isAnyCharacter()))),
has(expr(hasType(qualType(pointsTo(isAnyCharacter()))))))))
.bind("reinterpret-cast-expr"),
this);
}
void CharPtrCastCheck::check(
const ast_matchers::MatchFinder::MatchResult &Result) {
const auto ReinterpretCastExpr =
Result.Nodes.getNodeAs<CXXReinterpretCastExpr>("reinterpret-cast-expr");
const auto ToTypeSpan = ReinterpretCastExpr->getAngleBrackets();
const auto & SM = Result.Context->getSourceManager();
auto Diag =
diag(ReinterpretCastExpr->getExprLoc(),
"reinterpret_cast used for trivially safe character pointer cast");
Diag << ReinterpretCastExpr->getSourceRange();
auto Inside = tooling::getText(*ReinterpretCastExpr->getSubExprAsWritten(),
*Result.Context);
Diag << Inserter.createIncludeInsertion(SM.getFileID(ReinterpretCastExpr->getExprLoc()), "charptr-cast.hh");
llvm::Twine Replacement =
"charptr_cast" +
tooling::getText(CharSourceRange(ToTypeSpan, true), *Result.Context) +
"(" + Inside + ")";
Diag << FixItHint::CreateReplacement(ReinterpretCastExpr->getSourceRange(),
Replacement.str());
}
} // namespace nix::clang_tidy

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@ -0,0 +1,32 @@
#pragma once
///@file
#include <clang-tidy/ClangTidyCheck.h>
#include <clang-tidy/utils/IncludeInserter.h>
#include <clang/ASTMatchers/ASTMatchFinder.h>
#include <llvm/ADT/StringRef.h>
namespace nix::clang_tidy {
using namespace clang;
using namespace clang::tidy;
class CharPtrCastCheck : public ClangTidyCheck {
tidy::utils::IncludeInserter Inserter{
Options.getLocalOrGlobal("IncludeStyle",
tidy::utils::IncludeSorter::IS_Google),
false};
public:
CharPtrCastCheck(StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context) {}
void registerPPCallbacks(const SourceManager &, Preprocessor *PP,
Preprocessor *) override {
Inserter.registerPreprocessor(PP);
}
void registerMatchers(ast_matchers::MatchFinder *Finder) override;
void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
};
} // namespace nix::clang_tidy

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@ -2,6 +2,7 @@
#include <clang-tidy/ClangTidyModuleRegistry.h>
#include "FixIncludes.hh"
#include "HasPrefixSuffix.hh"
#include "CharPtrCast.hh"
namespace nix::clang_tidy {
using namespace clang;
@ -12,6 +13,7 @@ class NixClangTidyChecks : public ClangTidyModule {
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
CheckFactories.registerCheck<HasPrefixSuffixCheck>("lix-hasprefixsuffix");
CheckFactories.registerCheck<FixIncludesCheck>("lix-fixincludes");
CheckFactories.registerCheck<CharPtrCastCheck>("lix-charptrcast");
}
};

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@ -5,9 +5,10 @@ project('lix-clang-tidy', ['cpp', 'c'],
llvm = dependency('Clang', version: '>= 17', modules: ['libclang'])
sources = files(
'CharPtrCast.cc',
'FixIncludes.cc',
'HasPrefixSuffix.cc',
'LixClangTidyChecks.cc',
'FixIncludes.cc',
)
lix_clang_tidy = shared_module('lix-clang-tidy', sources,