forked from OSchip/llvm-project
124 lines
4.7 KiB
C++
124 lines
4.7 KiB
C++
//===--- UnusedParametersCheck.cpp - clang-tidy----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "UnusedParametersCheck.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/Lexer.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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void UnusedParametersCheck::registerMatchers(MatchFinder *Finder) {
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Finder->addMatcher(functionDecl().bind("function"), this);
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}
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template <typename T>
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static CharSourceRange removeNode(const MatchFinder::MatchResult &Result,
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const T *PrevNode, const T *Node,
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const T *NextNode) {
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if (NextNode)
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return CharSourceRange::getCharRange(Node->getLocStart(),
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NextNode->getLocStart());
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if (PrevNode)
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return CharSourceRange::getTokenRange(
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Lexer::getLocForEndOfToken(PrevNode->getLocEnd(), 0,
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*Result.SourceManager,
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Result.Context->getLangOpts()),
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Node->getLocEnd());
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return CharSourceRange::getTokenRange(Node->getSourceRange());
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}
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static FixItHint removeParameter(const MatchFinder::MatchResult &Result,
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const FunctionDecl *Function, unsigned Index) {
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return FixItHint::CreateRemoval(removeNode(
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Result, Index > 0 ? Function->getParamDecl(Index - 1) : nullptr,
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Function->getParamDecl(Index),
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Index + 1 < Function->getNumParams() ? Function->getParamDecl(Index + 1)
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: nullptr));
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}
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static FixItHint removeArgument(const MatchFinder::MatchResult &Result,
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const CallExpr *Call, unsigned Index) {
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return FixItHint::CreateRemoval(removeNode(
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Result, Index > 0 ? Call->getArg(Index - 1) : nullptr,
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Call->getArg(Index),
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Index + 1 < Call->getNumArgs() ? Call->getArg(Index + 1) : nullptr));
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}
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void UnusedParametersCheck::warnOnUnusedParameter(
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const MatchFinder::MatchResult &Result, const FunctionDecl *Function,
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unsigned ParamIndex) {
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const auto *Param = Function->getParamDecl(ParamIndex);
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auto MyDiag = diag(Param->getLocation(), "parameter '%0' is unused")
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<< Param->getName();
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auto UsedByRef = [&] {
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return !ast_matchers::match(
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decl(hasDescendant(
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declRefExpr(to(equalsNode(Function)),
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unless(hasAncestor(
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callExpr(callee(equalsNode(Function)))))))),
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*Result.Context->getTranslationUnitDecl(), *Result.Context)
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.empty();
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};
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// Comment out parameter name for non-local functions.
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if (Function->isExternallyVisible() ||
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!Result.SourceManager->isInMainFile(Function->getLocation()) ||
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UsedByRef()) {
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SourceRange RemovalRange(Param->getLocation(), Param->getLocEnd());
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// Note: We always add a space before the '/*' to not accidentally create a
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// '*/*' for pointer types, which doesn't start a comment. clang-format will
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// clean this up afterwards.
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MyDiag << FixItHint::CreateReplacement(
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RemovalRange, (Twine(" /*") + Param->getName() + "*/").str());
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return;
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}
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// Fix all redeclarations.
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for (const FunctionDecl *FD : Function->redecls())
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if (FD->param_size())
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MyDiag << removeParameter(Result, FD, ParamIndex);
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// Fix all call sites.
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auto CallMatches = ast_matchers::match(
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decl(forEachDescendant(
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callExpr(callee(functionDecl(equalsNode(Function)))).bind("x"))),
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*Result.Context->getTranslationUnitDecl(), *Result.Context);
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for (const auto &Match : CallMatches)
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MyDiag << removeArgument(Result, Match.getNodeAs<CallExpr>("x"),
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ParamIndex);
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}
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void UnusedParametersCheck::check(const MatchFinder::MatchResult &Result) {
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const auto *Function = Result.Nodes.getNodeAs<FunctionDecl>("function");
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if (!Function->doesThisDeclarationHaveABody() ||
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!Function->hasWrittenPrototype() ||
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Function->isTemplateInstantiation())
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return;
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if (const auto *Method = dyn_cast<CXXMethodDecl>(Function))
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if (Method->isLambdaStaticInvoker())
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return;
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for (unsigned i = 0, e = Function->getNumParams(); i != e; ++i) {
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const auto *Param = Function->getParamDecl(i);
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if (Param->isUsed() || Param->isReferenced() || !Param->getDeclName() ||
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Param->hasAttr<UnusedAttr>())
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continue;
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warnOnUnusedParameter(Result, Function, i);
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}
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}
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} // namespace tidy
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} // namespace clang
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