diff --git a/clang-tools-extra/clang-tidy/llvm/AvoidCastInConditionalCheck.h b/clang-tools-extra/clang-tidy/llvm/AvoidCastInConditionalCheck.h new file mode 100644 --- /dev/null +++ b/clang-tools-extra/clang-tidy/llvm/AvoidCastInConditionalCheck.h @@ -0,0 +1,58 @@ +//===--- AvoidCastInConditionalCheck.h - clang-tidy -------------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_AVOIDCASTINCONDITIONALCHECK_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_AVOIDCASTINCONDITIONALCHECK_H + +#include "../ClangTidy.h" + +namespace clang { +namespace tidy { +namespace llvm { + +/// \brief Finds uses of ``cast<>`` in conditionals of ``if``, ``while`` or +/// ``do`` statements, which will assert rather than return a null pointer. It +/// also finds uses of ``dyn_cast<>`` in conditionals where the return value is +/// not captured. +/// +/// Finds cases like these: +/// \code +/// if (auto x = cast(y)) {} +/// // is replaced by: +/// if (auto x = dyn_cast(y)) {} +/// +/// if (cast(y)) {} +/// // is replaced by: +/// if (isa(y)) {} +/// +/// if (dyn_cast(y)) {} +/// // is replaced by: +/// if (isa(y)) {} +/// \endcode +/// +/// // These are ignored. +/// \code +/// if (auto f = cast(y)->foo()) {} +/// if (cast(y)->foo()) {} +/// \endcode +/// +/// For the user-facing documentation see: +/// http://clang.llvm.org/extra/clang-tidy/checks/llvm-avoid-cast-in-conditional.html +class AvoidCastInConditionalCheck : public ClangTidyCheck { +public: + AvoidCastInConditionalCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; +}; + +} // namespace llvm +} // namespace tidy +} // namespace clang + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_LLVM_AVOIDCASTINCONDITIONALCHECK_H diff --git a/clang-tools-extra/clang-tidy/llvm/AvoidCastInConditionalCheck.cpp b/clang-tools-extra/clang-tidy/llvm/AvoidCastInConditionalCheck.cpp new file mode 100644 --- /dev/null +++ b/clang-tools-extra/clang-tidy/llvm/AvoidCastInConditionalCheck.cpp @@ -0,0 +1,156 @@ +//===--- AvoidCastInConditionalCheck.cpp - clang-tidy ---------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "AvoidCastInConditionalCheck.h" +#include "clang/AST/ASTContext.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" + +using namespace clang::ast_matchers; + +namespace clang { +namespace tidy { +namespace llvm { + +void AvoidCastInConditionalCheck::registerMatchers(MatchFinder *Finder) { + if (!getLangOpts().CPlusPlus) + return; + + Finder->addMatcher( + stmt(anyOf( + ifStmt(anyOf( + hasConditionVariableStatement(declStmt(containsDeclaration( + 0, varDecl(hasInitializer( + callExpr(callee(namedDecl(hasName("cast")))) + .bind("cast-assign")))))), + hasCondition(implicitCastExpr(anyOf( + has(callExpr(callee(namedDecl(hasName("cast")))) + .bind("cast")), + has(callExpr(callee(namedDecl(hasName("dyn_cast")))) + .bind("dyn_cast"))))))), + whileStmt(anyOf( + has(declStmt(containsDeclaration( + 0, varDecl(hasInitializer( + callExpr(callee(namedDecl(hasName("cast")))) + .bind("cast-assign")))))), + hasCondition(implicitCastExpr(anyOf( + has(callExpr(callee(namedDecl(hasName("cast")))) + .bind("cast")), + has(callExpr(callee(namedDecl(hasName("dyn_cast")))) + .bind("dyn_cast"))))))), + doStmt(hasCondition(implicitCastExpr(anyOf( + has(callExpr(callee(namedDecl(hasName("cast")))).bind("cast")), + has(callExpr(callee(namedDecl(hasName("dyn_cast")))) + .bind("dyn_cast")))))), + binaryOperator( + allOf( + unless(isExpansionInFileMatching( + "llvm/include/llvm/Support/Casting.h")), + hasOperatorName("&&"), + hasLHS( + implicitCastExpr(has(cxxMemberCallExpr().bind("lhs")))), + hasRHS(anyOf( + callExpr( + allOf(hasArgument(0, cxxMemberCallExpr().bind("arg")), + callee(namedDecl(hasName("isa")).bind("func")))) + .bind("rhs"), + implicitCastExpr(has( + callExpr( + allOf(hasArgument( + 0, cxxMemberCallExpr().bind("arg")), + callee( + namedDecl( + anyOf(hasName("cast"), + hasName("dyn_cast"), + hasName("dyn_cast_or_null"))) + .bind("func")))) + .bind("rhs"))))))) + .bind("and"))), + this); +} + +void AvoidCastInConditionalCheck::check( + const MatchFinder::MatchResult &Result) { + if (const auto *MatchedDecl = + Result.Nodes.getNodeAs("cast-assign")) { + SourceLocation StartLoc = MatchedDecl->getCallee()->getExprLoc(); + SourceLocation EndLoc = + StartLoc.getLocWithOffset(StringRef("cast").size() - 1); + + if (StartLoc.isMacroID()) + return; + + diag(MatchedDecl->getBeginLoc(), + "cast<> in conditional will assert rather than return a null pointer") + << FixItHint::CreateReplacement(SourceRange(StartLoc, EndLoc), + "dyn_cast"); + } else if (const auto *MatchedDecl = + Result.Nodes.getNodeAs("cast")) { + SourceLocation StartLoc = MatchedDecl->getCallee()->getExprLoc(); + SourceLocation EndLoc = + StartLoc.getLocWithOffset(StringRef("cast").size() - 1); + + if (StartLoc.isMacroID()) + return; + + diag(MatchedDecl->getBeginLoc(), + "cast<> in conditional will assert rather than return a null pointer") + << FixItHint::CreateReplacement(SourceRange(StartLoc, EndLoc), "isa"); + } else if (const auto *MatchedDecl = + Result.Nodes.getNodeAs("dyn_cast")) { + SourceLocation StartLoc = MatchedDecl->getCallee()->getExprLoc(); + SourceLocation EndLoc = + StartLoc.getLocWithOffset(StringRef("dyn_cast").size() - 1); + + if (StartLoc.isMacroID()) + return; + + diag(MatchedDecl->getBeginLoc(), "return value from dyn_cast<> not used") + << FixItHint::CreateReplacement(SourceRange(StartLoc, EndLoc), "isa"); + } else if (const auto *MatchedDecl = + Result.Nodes.getNodeAs("and")) { + const auto *Arg = Result.Nodes.getNodeAs("arg"); + const auto *LHS = Result.Nodes.getNodeAs("lhs"); + const auto *RHS = Result.Nodes.getNodeAs("rhs"); + const auto *Func = Result.Nodes.getNodeAs("func"); + + if (RHS->getBeginLoc().isMacroID()) + return; + + CharSourceRange ArgRange = + CharSourceRange::getTokenRange(Arg->getSourceRange()); + std::string ArgString( + Lexer::getSourceText(ArgRange, *Result.SourceManager, getLangOpts())); + + CharSourceRange LHSRange = + CharSourceRange::getTokenRange(LHS->getSourceRange()); + std::string LHSString( + Lexer::getSourceText(LHSRange, *Result.SourceManager, getLangOpts())); + + if (ArgString != LHSString) + return; + + CharSourceRange RHSRange = + CharSourceRange::getTokenRange(RHS->getSourceRange()); + std::string RHSString( + Lexer::getSourceText(RHSRange, *Result.SourceManager, getLangOpts())); + + std::string Replacement("dyn_cast_or_null"); + Replacement += RHSString.substr(Func->getName().size()); + + diag(MatchedDecl->getBeginLoc(), + "method %0 is called twice and could be expensive") + << LHS->getMethodDecl() + << FixItHint::CreateReplacement(SourceRange(MatchedDecl->getBeginLoc(), + MatchedDecl->getEndLoc()), + Replacement); + } +} + +} // namespace llvm +} // namespace tidy +} // namespace clang diff --git a/clang-tools-extra/clang-tidy/llvm/CMakeLists.txt b/clang-tools-extra/clang-tidy/llvm/CMakeLists.txt --- a/clang-tools-extra/clang-tidy/llvm/CMakeLists.txt +++ b/clang-tools-extra/clang-tidy/llvm/CMakeLists.txt @@ -1,6 +1,7 @@ set(LLVM_LINK_COMPONENTS support) add_clang_library(clangTidyLLVMModule + AvoidCastInConditionalCheck.cpp HeaderGuardCheck.cpp IncludeOrderCheck.cpp LLVMTidyModule.cpp diff --git a/clang-tools-extra/clang-tidy/llvm/LLVMTidyModule.cpp b/clang-tools-extra/clang-tidy/llvm/LLVMTidyModule.cpp --- a/clang-tools-extra/clang-tidy/llvm/LLVMTidyModule.cpp +++ b/clang-tools-extra/clang-tidy/llvm/LLVMTidyModule.cpp @@ -10,6 +10,7 @@ #include "../ClangTidyModule.h" #include "../ClangTidyModuleRegistry.h" #include "../readability/NamespaceCommentCheck.h" +#include "AvoidCastInConditionalCheck.h" #include "HeaderGuardCheck.h" #include "IncludeOrderCheck.h" #include "TwineLocalCheck.h" @@ -21,6 +22,8 @@ class LLVMModule : public ClangTidyModule { public: void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override { + CheckFactories.registerCheck( + "llvm-avoid-cast-in-conditional"); CheckFactories.registerCheck("llvm-header-guard"); CheckFactories.registerCheck("llvm-include-order"); CheckFactories.registerCheck( diff --git a/clang-tools-extra/clang-tidy/utils/HeaderFileExtensionsUtils.h b/clang-tools-extra/clang-tidy/utils/HeaderFileExtensionsUtils.h --- a/clang-tools-extra/clang-tidy/utils/HeaderFileExtensionsUtils.h +++ b/clang-tools-extra/clang-tidy/utils/HeaderFileExtensionsUtils.h @@ -18,7 +18,7 @@ namespace tidy { namespace utils { -typedef llvm::SmallSet HeaderFileExtensionsSet; +using HeaderFileExtensionsSet = ::llvm::SmallSet; /// \brief Checks whether expansion location of \p Loc is in header file. bool isExpansionLocInHeaderFile( diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -130,6 +130,14 @@ ` now supports `OverrideSpelling` and `FinalSpelling` options. +- New :doc:`llvm-avoid-cast-in-conditional + ` check. + + Finds uses of ``cast<>`` in conditionals of ``if``, ``while`` or + ``do`` statements, which will assert rather than return a null + pointer. It also finds uses of ``dyn_cast<>`` in conditionals where + the return value is not captured. + - New :doc:`openmp-exception-escape ` check. diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst --- a/clang-tools-extra/docs/clang-tidy/checks/list.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst @@ -175,6 +175,7 @@ hicpp-use-nullptr (redirects to modernize-use-nullptr) hicpp-use-override (redirects to modernize-use-override) hicpp-vararg (redirects to cppcoreguidelines-pro-type-vararg) + llvm-avoid-cast-in-conditional llvm-header-guard llvm-include-order llvm-namespace-comment diff --git a/clang-tools-extra/docs/clang-tidy/checks/llvm-avoid-cast-in-conditional.rst b/clang-tools-extra/docs/clang-tidy/checks/llvm-avoid-cast-in-conditional.rst new file mode 100644 --- /dev/null +++ b/clang-tools-extra/docs/clang-tidy/checks/llvm-avoid-cast-in-conditional.rst @@ -0,0 +1,28 @@ +.. title:: clang-tidy - llvm-avoid-cast-in-conditional + +llvm-avoid-cast-in-conditional +============================== + + Finds uses of ``cast<>`` in conditionals of ``if``, ``while`` or + ``do`` statements, which will assert rather than return a null + pointer. It also finds uses of ``dyn_cast<>`` in conditionals where + the return value is not captured. + +.. code-block:: c++ + + // Finds these: + if (auto x = cast(y)) {} + // is replaced by: + if (auto x = dyn_cast(y)) {} + + if (cast(y)) {} + // is replaced by: + if (isa(y)) {} + + if (dyn_cast(y)) {} + // is replaced by: + if (isa(y)) {} + + // These are ignored. + if (auto f = cast(y)->foo()) {} + if (cast(y)->foo()) {} diff --git a/clang-tools-extra/test/clang-tidy/llvm-avoid-cast-in-conditional.cpp b/clang-tools-extra/test/clang-tidy/llvm-avoid-cast-in-conditional.cpp new file mode 100644 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/llvm-avoid-cast-in-conditional.cpp @@ -0,0 +1,118 @@ +// RUN: %check_clang_tidy %s llvm-avoid-cast-in-conditional %t + +#define CAST(T, Obj) cast(Obj) +#define ISA(T, Obj) isa(Obj) +#define ISA_OR_NULL(T, Obj) Obj &&isa(Obj) + +struct X; +struct Y; +struct Z { + int foo(); + X *bar(); +}; + +template +bool isa(Y *); +template +X *cast(Y *); +template +X *dyn_cast(Y *); +template +X *dyn_cast_or_null(Y *); + +bool foo(Y *y, Z *z) { + if (auto x = cast(y)) + return true; + // CHECK-MESSAGES: :[[@LINE-2]]:16: warning: {{cast<> in conditional .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: if (auto x = dyn_cast(y)) + + if (cast(y)) + return true; + // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: {{cast<> in conditional .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: if (isa(y)) + + if (dyn_cast(y)) + return true; + // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: {{.*dyn_cast<> not used .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: if (isa(y)) + + // These don't trigger a warning. + if (auto x = cast(y)->foo()) + return true; + if (cast(y)->foo()) + return true; + + while (auto x = cast(y)) + break; + // CHECK-MESSAGES: :[[@LINE-2]]:19: warning: {{cast<> in conditional .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: while (auto x = dyn_cast(y)) + + while (cast(y)) + break; + // CHECK-MESSAGES: :[[@LINE-2]]:10: warning: {{cast<> in conditional .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: while (isa(y)) + + while (dyn_cast(y)) + break; + // CHECK-MESSAGES: :[[@LINE-2]]:10: warning: {{.*dyn_cast<> not used .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: while (isa(y)) + + // These don't trigger a warning. + while (auto x = cast(y)->foo()) + break; + while (cast(y)->foo()) + break; + + do { + break; + } while (cast(y)); + // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: {{cast<> in conditional .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: while (isa(y)); + + do { + break; + } while (dyn_cast(y)); + // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: {{.*dyn_cast<> not used .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: while (isa(y)); + + if (z->bar() && isa(z->bar())) + return true; + // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: {{method .* is called twice .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: if (dyn_cast_or_null(z->bar())) + + if (z->bar() && cast(z->bar())) + return true; + // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: {{method .* is called twice .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: if (dyn_cast_or_null(z->bar())) + + if (z->bar() && dyn_cast(z->bar())) + return true; + // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: {{method .* is called twice .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: if (dyn_cast_or_null(z->bar())) + + if (z->bar() && dyn_cast_or_null(z->bar())) + return true; + // CHECK-MESSAGES: :[[@LINE-2]]:7: warning: {{method .* is called twice .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: if (dyn_cast_or_null(z->bar())) + + bool b = z->bar() && cast(z->bar()); + // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: {{method .* is called twice .*llvm-avoid-cast-in-conditional}} + // CHECK-FIXES: bool b = dyn_cast_or_null(z->bar()); + + // These don't trigger a warning. + if (auto x = CAST(X, y)) + return true; + if (z->bar() && ISA(Y, z->bar())) + return true; + if (ISA_OR_NULL(Y, z->bar())) + return true; + if (y && isa(y)) + return true; + if (y && cast(z->bar())) + return true; + if (z && cast(y)->foo()) + return true; + bool b2 = y && cast(z); + + return false; +}