
Adds a flag to `ClangTidyContext` that is used to indicate to checks that fixes will only be applied one at a time. This is to indicate to checks that each fix emitted should not depend on any other fixes emitted across the translation unit. I've currently implemented the `IncludeInserter`, `LoopConvertCheck` and `PreferMemberInitializerCheck` to use these support these modes. Reasoning behind this is in use cases like `clangd` it's only possible to apply one fix at a time. For include inserter checks, the include is only added once for the first diagnostic that requires it, this will result in subsequent fixes not having the included needed. A similar issue is seen in the `PreferMemberInitializerCheck` where the `:` will only be added for the first member that needs fixing. Fixes emitted in `StandaloneDiagsMode` will likely result in malformed code if they are applied all together, conversely fixes currently emitted may result in malformed code if they are applied one at a time. For this reason invoking `clang-tidy` from the binary will always with `StandaloneDiagsMode` disabled, However using it as a library its possible to select the mode you wish to use, `clangd` always selects `StandaloneDiagsMode`. This is an example of the current behaviour failing ```lang=c++ struct Foo { int A, B; Foo(int D, int E) { A = D; B = E; // Fix Here } }; ``` Incorrectly transformed to: ```lang=c++ struct Foo { int A, B; Foo(int D, int E), B(E) { A = D; // Fix Here } }; ``` In `StandaloneDiagsMode`, it gets transformed to: ```lang=c++ struct Foo { int A, B; Foo(int D, int E) : B(E) { A = D; // Fix Here } }; ``` Reviewed By: sammccall Differential Revision: https://reviews.llvm.org/D97121
117 lines
4.0 KiB
C++
117 lines
4.0 KiB
C++
//===--- InitVariablesCheck.cpp - clang-tidy ------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "InitVariablesCheck.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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#include "clang/Lex/PPCallbacks.h"
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#include "clang/Lex/Preprocessor.h"
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using namespace clang::ast_matchers;
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namespace clang {
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namespace tidy {
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namespace cppcoreguidelines {
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namespace {
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AST_MATCHER(VarDecl, isLocalVarDecl) { return Node.isLocalVarDecl(); }
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} // namespace
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InitVariablesCheck::InitVariablesCheck(StringRef Name,
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ClangTidyContext *Context)
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: ClangTidyCheck(Name, Context),
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IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
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utils::IncludeSorter::IS_LLVM),
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areDiagsSelfContained()),
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MathHeader(Options.get("MathHeader", "<math.h>")) {}
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void InitVariablesCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
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Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
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Options.store(Opts, "MathHeader", MathHeader);
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}
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void InitVariablesCheck::registerMatchers(MatchFinder *Finder) {
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std::string BadDecl = "badDecl";
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Finder->addMatcher(
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varDecl(unless(hasInitializer(anything())), unless(isInstantiated()),
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isLocalVarDecl(), unless(isStaticLocal()), isDefinition(),
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unless(hasParent(cxxCatchStmt())),
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optionally(hasParent(declStmt(hasParent(
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cxxForRangeStmt(hasLoopVariable(varDecl().bind(BadDecl))))))),
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unless(equalsBoundNode(BadDecl)))
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.bind("vardecl"),
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this);
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}
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void InitVariablesCheck::registerPPCallbacks(const SourceManager &SM,
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Preprocessor *PP,
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Preprocessor *ModuleExpanderPP) {
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IncludeInserter.registerPreprocessor(PP);
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}
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void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
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const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl");
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const ASTContext &Context = *Result.Context;
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const SourceManager &Source = Context.getSourceManager();
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// We want to warn about cases where the type name
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// comes from a macro like this:
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//
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// TYPENAME_FROM_MACRO var;
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//
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// but not if the entire declaration comes from
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// one:
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//
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// DEFINE_SOME_VARIABLE();
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//
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// or if the definition comes from a macro like SWAP
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// that uses an internal temporary variable.
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//
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// Thus check that the variable name does
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// not come from a macro expansion.
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if (MatchedDecl->getEndLoc().isMacroID())
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return;
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QualType TypePtr = MatchedDecl->getType();
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llvm::Optional<const char *> InitializationString = llvm::None;
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bool AddMathInclude = false;
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if (TypePtr->isEnumeralType())
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InitializationString = nullptr;
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else if (TypePtr->isIntegerType())
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InitializationString = " = 0";
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else if (TypePtr->isFloatingType()) {
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InitializationString = " = NAN";
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AddMathInclude = true;
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} else if (TypePtr->isAnyPointerType()) {
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if (getLangOpts().CPlusPlus11)
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InitializationString = " = nullptr";
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else
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InitializationString = " = NULL";
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}
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if (InitializationString) {
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auto Diagnostic =
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diag(MatchedDecl->getLocation(), "variable %0 is not initialized")
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<< MatchedDecl;
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if (*InitializationString != nullptr)
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Diagnostic << FixItHint::CreateInsertion(
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MatchedDecl->getLocation().getLocWithOffset(
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MatchedDecl->getName().size()),
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*InitializationString);
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if (AddMathInclude) {
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Diagnostic << IncludeInserter.createIncludeInsertion(
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Source.getFileID(MatchedDecl->getBeginLoc()), MathHeader);
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}
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}
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}
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} // namespace cppcoreguidelines
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} // namespace tidy
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} // namespace clang
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