From 35c3f61d749d78917ee572f672c89993692047b9 Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Tue, 18 Mar 2014 04:46:45 +0000 Subject: [PATCH] Add an argument comment checker to clang-tidy. This checks that parameters named in comments that appear before arguments in function and constructor calls match the parameter name used in the callee's declaration. For example: void f(int x, int y); void g() { f(/*y=*/0, /*z=*/0); } contains two violations of the policy, as the names 'x' and 'y' used in the declaration do not match names 'y' and 'z' used at the call site. I think there is significant value in being able to check/enforce this policy as a way of guarding against accidental API misuse and silent breakages caused by API changes. Although this pattern appears somewhat frequently in the LLVM codebase, this policy is not prescribed by the LLVM coding standards at the moment, so it lives under 'misc'. Differential Revision: http://llvm-reviews.chandlerc.com/D2914 llvm-svn: 204113 --- .../clang-tidy/misc/ArgumentCommentCheck.cpp | 166 ++++++++++++++++++ .../clang-tidy/misc/ArgumentCommentCheck.h | 40 +++++ .../clang-tidy/misc/CMakeLists.txt | 1 + .../clang-tidy/misc/MiscTidyModule.cpp | 4 + .../test/clang-tidy/arg-comments.cpp | 21 +++ .../unittests/clang-tidy/CMakeLists.txt | 4 +- .../unittests/clang-tidy/Makefile | 2 +- .../unittests/clang-tidy/MiscModuleTest.cpp | 41 +++++ 8 files changed, 277 insertions(+), 2 deletions(-) create mode 100644 clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.cpp create mode 100644 clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.h create mode 100644 clang-tools-extra/test/clang-tidy/arg-comments.cpp create mode 100644 clang-tools-extra/unittests/clang-tidy/MiscModuleTest.cpp diff --git a/clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.cpp b/clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.cpp new file mode 100644 index 000000000000..4ef9f8f1b821 --- /dev/null +++ b/clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.cpp @@ -0,0 +1,166 @@ +//===--- ArgumentCommentCheck.cpp - clang-tidy ----------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "ArgumentCommentCheck.h" +#include "../ClangTidy.h" +#include "../ClangTidyModule.h" +#include "../ClangTidyModuleRegistry.h" +#include "clang/AST/ASTContext.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/Lex/Lexer.h" +#include "clang/Lex/Token.h" + +using namespace clang::ast_matchers; + +namespace clang { +namespace tidy { + +void ArgumentCommentCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher(callExpr(unless(operatorCallExpr())).bind("expr"), this); + Finder->addMatcher(constructExpr().bind("expr"), this); +} + +std::vector> +ArgumentCommentCheck::getCommentsInRange(ASTContext *Ctx, SourceRange Range) { + std::vector> Comments; + auto &SM = Ctx->getSourceManager(); + std::pair BeginLoc = SM.getDecomposedLoc(Range.getBegin()), + EndLoc = SM.getDecomposedLoc(Range.getEnd()); + + if (BeginLoc.first != EndLoc.first) + return Comments; + + bool Invalid = false; + StringRef Buffer = SM.getBufferData(BeginLoc.first, &Invalid); + if (Invalid) + return Comments; + + const char *StrData = Buffer.data() + BeginLoc.second; + + Lexer TheLexer(SM.getLocForStartOfFile(BeginLoc.first), Ctx->getLangOpts(), + Buffer.begin(), StrData, Buffer.end()); + TheLexer.SetCommentRetentionState(true); + + while (true) { + Token Tok; + if (TheLexer.LexFromRawLexer(Tok)) + break; + if (Tok.getLocation() == Range.getEnd() || Tok.getKind() == tok::eof) + break; + + if (Tok.getKind() == tok::comment) { + std::pair CommentLoc = + SM.getDecomposedLoc(Tok.getLocation()); + assert(CommentLoc.first == BeginLoc.first); + Comments.emplace_back( + Tok.getLocation(), + StringRef(Buffer.begin() + CommentLoc.second, Tok.getLength())); + } + } + + return Comments; +} + +bool +ArgumentCommentCheck::isLikelyTypo(llvm::ArrayRef Params, + StringRef ArgName, unsigned ArgIndex) { + std::string ArgNameLower = ArgName.lower(); + unsigned UpperBound = (ArgName.size() + 2) / 3 + 1; + unsigned ThisED = StringRef(ArgNameLower).edit_distance( + Params[ArgIndex]->getIdentifier()->getName().lower(), + /*AllowReplacements=*/true, UpperBound); + if (ThisED >= UpperBound) + return false; + + for (const auto &Param : Params) { + if (&Param - Params.begin() == ArgIndex) + continue; + IdentifierInfo *II = Param->getIdentifier(); + if (!II) + continue; + + const unsigned Threshold = 2; + // Other parameters must be an edit distance at least Threshold more away + // from this parameter. This gives us greater confidence that this is a typo + // of this parameter and not one with a similar name. + unsigned OtherED = StringRef(ArgNameLower).edit_distance( + II->getName().lower(), + /*AllowReplacements=*/true, ThisED + Threshold); + if (OtherED < ThisED + Threshold) + return false; + } + + return true; +} + +void ArgumentCommentCheck::checkCallArgs(ASTContext *Ctx, + const FunctionDecl *Callee, + SourceLocation ArgBeginLoc, + llvm::ArrayRef Args) { + Callee = Callee->getFirstDecl(); + for (unsigned i = 0, + e = std::min(Args.size(), Callee->getNumParams()); + i != e; ++i) { + const ParmVarDecl *PVD = Callee->getParamDecl(i); + IdentifierInfo *II = PVD->getIdentifier(); + if (!II) + continue; + + SourceLocation BeginSLoc, EndSLoc = Args[i]->getLocStart(); + if (i == 0) + BeginSLoc = ArgBeginLoc; + else + BeginSLoc = Args[i - 1]->getLocEnd(); + if (BeginSLoc.isMacroID() || EndSLoc.isMacroID()) + continue; + + for (auto Comment : + getCommentsInRange(Ctx, SourceRange(BeginSLoc, EndSLoc))) { + llvm::SmallVector Matches; + if (IdentRE.match(Comment.second, &Matches)) { + if (Matches[2] != II->getName()) { + { + DiagnosticBuilder Diag = + diag(Comment.first, "argument name '%0' in comment does not " + "match parameter name %1") + << Matches[2] << II; + if (isLikelyTypo(Callee->parameters(), Matches[2], i)) { + Diag << FixItHint::CreateReplacement( + Comment.first, + (Matches[1] + II->getName() + Matches[3]).str()); + } + } + diag(PVD->getLocation(), "%0 declared here", DiagnosticIDs::Note) + << II; + } + } + } + } +} + +void ArgumentCommentCheck::check(const MatchFinder::MatchResult &Result) { + const Expr *E = Result.Nodes.getNodeAs("expr"); + if (auto Call = dyn_cast(E)) { + const FunctionDecl *Callee = Call->getDirectCallee(); + if (!Callee) + return; + + checkCallArgs(Result.Context, Callee, Call->getCallee()->getLocEnd(), + llvm::makeArrayRef(Call->getArgs(), Call->getNumArgs())); + } else { + auto Construct = cast(E); + checkCallArgs( + Result.Context, Construct->getConstructor(), + Construct->getParenOrBraceRange().getBegin(), + llvm::makeArrayRef(Construct->getArgs(), Construct->getNumArgs())); + } +} + +} // namespace tidy +} // namespace clang diff --git a/clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.h b/clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.h new file mode 100644 index 000000000000..8180a2ce9fdc --- /dev/null +++ b/clang-tools-extra/clang-tidy/misc/ArgumentCommentCheck.h @@ -0,0 +1,40 @@ +//===--- ArgumentCommentCheck.h - clang-tidy --------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_ARG_COMMENT_CHECK_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_ARG_COMMENT_CHECK_H + +#include "../ClangTidy.h" +#include "llvm/Support/Regex.h" + +namespace clang { +namespace tidy { + +/// \brief Checks that argument comments match parameter names. +class ArgumentCommentCheck : public ClangTidyCheck { +public: + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; + +private: + llvm::Regex IdentRE{ "^(/\\* *)([_A-Za-z][_A-Za-z0-9]*)( *= *\\*/)$" }; + + bool isLikelyTypo(llvm::ArrayRef Params, StringRef ArgName, + unsigned ArgIndex); + std::vector> + getCommentsInRange(ASTContext *Ctx, SourceRange Range); + void checkCallArgs(ASTContext *Ctx, const FunctionDecl *Callee, + SourceLocation ArgBeginLoc, + llvm::ArrayRef Args); +}; + +} // namespace tidy +} // namespace clang + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_ARG_COMMENT_CHECK_H diff --git a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt index 5a60a35dd6d6..8c9b5dd3c0bc 100644 --- a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt +++ b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt @@ -1,6 +1,7 @@ set(LLVM_LINK_COMPONENTS support) add_clang_library(clangTidyMiscModule + ArgumentCommentCheck.cpp MiscTidyModule.cpp LINK_LIBS diff --git a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp index e262dc356d09..f7f657addfa3 100644 --- a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp +++ b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp @@ -10,6 +10,7 @@ #include "../ClangTidy.h" #include "../ClangTidyModule.h" #include "../ClangTidyModuleRegistry.h" +#include "ArgumentCommentCheck.h" namespace clang { namespace tidy { @@ -17,6 +18,9 @@ namespace tidy { class MiscModule : public ClangTidyModule { public: void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override { + CheckFactories.addCheckFactory( + "misc-argument-comment", + new ClangTidyCheckFactory()); } }; diff --git a/clang-tools-extra/test/clang-tidy/arg-comments.cpp b/clang-tools-extra/test/clang-tidy/arg-comments.cpp new file mode 100644 index 000000000000..32b95767bd22 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/arg-comments.cpp @@ -0,0 +1,21 @@ +// RUN: clang-tidy --checks=misc-argument-comment %s -- | FileCheck %s + +// FIXME: clang-tidy should provide a -verify mode to make writing these checks +// easier and more accurate. + +// CHECK-NOT: warning + +void f(int x, int y); + +void ffff(int xxxx, int yyyy); + +void g() { + // CHECK: [[@LINE+5]]:5: warning: argument name 'y' in comment does not match parameter name 'x' + // CHECK: :8:12: note: 'x' declared here + // CHECK: [[@LINE+3]]:14: warning: argument name 'z' in comment does not match parameter name 'y' + // CHECK: :8:19: note: 'y' declared here + // CHECK-NOT: warning + f(/*y=*/0, /*z=*/0); +} + +// CHECK-NOT: warning diff --git a/clang-tools-extra/unittests/clang-tidy/CMakeLists.txt b/clang-tools-extra/unittests/clang-tidy/CMakeLists.txt index 2778571789d2..5d29b0f9e8f0 100644 --- a/clang-tools-extra/unittests/clang-tidy/CMakeLists.txt +++ b/clang-tools-extra/unittests/clang-tidy/CMakeLists.txt @@ -8,7 +8,8 @@ include_directories(${CLANG_LINT_SOURCE_DIR}) add_extra_unittest(ClangTidyTests LLVMModuleTest.cpp - GoogleModuleTest.cpp) + GoogleModuleTest.cpp + MiscModuleTest.cpp) target_link_libraries(ClangTidyTests clangAST @@ -18,5 +19,6 @@ target_link_libraries(ClangTidyTests clangTidy clangTidyGoogleModule clangTidyLLVMModule + clangTidyMiscModule clangTooling ) diff --git a/clang-tools-extra/unittests/clang-tidy/Makefile b/clang-tools-extra/unittests/clang-tidy/Makefile index c5b9823eb0f7..79832262c447 100644 --- a/clang-tools-extra/unittests/clang-tidy/Makefile +++ b/clang-tools-extra/unittests/clang-tidy/Makefile @@ -14,7 +14,7 @@ TESTNAME = ClangTidy LINK_COMPONENTS := asmparser bitreader support MC MCParser option \ TransformUtils USEDLIBS = clangTidy.a clangTidyLLVMModule.a clangTidyGoogleModule.a \ - clangTidy.a \ + clangTidyMiscModule.a clangTidy.a \ clangStaticAnalyzerFrontend.a clangStaticAnalyzerCheckers.a \ clangStaticAnalyzerCore.a \ clangFormat.a clangTooling.a clangFrontend.a clangSerialization.a \ diff --git a/clang-tools-extra/unittests/clang-tidy/MiscModuleTest.cpp b/clang-tools-extra/unittests/clang-tidy/MiscModuleTest.cpp new file mode 100644 index 000000000000..c26783dc7240 --- /dev/null +++ b/clang-tools-extra/unittests/clang-tidy/MiscModuleTest.cpp @@ -0,0 +1,41 @@ +#include "ClangTidyTest.h" +#include "google/GoogleTidyModule.h" +#include "misc/ArgumentCommentCheck.h" +#include "gtest/gtest.h" + +namespace clang { +namespace tidy { +namespace test { + +#define EXPECT_NO_CHANGES(Check, Code) \ + EXPECT_EQ(Code, runCheckOnCode(Code)) + +TEST(ArgumentCommentCheckTest, CorrectComments) { + EXPECT_NO_CHANGES(ArgumentCommentCheck, + "void f(int x, int y); void g() { f(/*x=*/0, /*y=*/0); }"); + EXPECT_NO_CHANGES(ArgumentCommentCheck, + "struct C { C(int x, int y); }; C c(/*x=*/0, /*y=*/0);"); +} + +TEST(ArgumentCommentCheckTest, ThisEditDistanceAboveThreshold) { + EXPECT_NO_CHANGES(ArgumentCommentCheck, + "void f(int xxx); void g() { f(/*xyz=*/0); }"); +} + +TEST(ArgumentCommentCheckTest, OtherEditDistanceAboveThreshold) { + EXPECT_EQ("void f(int xxx, int yyy); void g() { f(/*xxx=*/0, 0); }", + runCheckOnCode( + "void f(int xxx, int yyy); void g() { f(/*Xxx=*/0, 0); }")); + EXPECT_EQ("struct C { C(int xxx, int yyy); }; C c(/*xxx=*/0, 0);", + runCheckOnCode( + "struct C { C(int xxx, int yyy); }; C c(/*Xxx=*/0, 0);")); +} + +TEST(ArgumentCommentCheckTest, OtherEditDistanceBelowThreshold) { + EXPECT_NO_CHANGES(ArgumentCommentCheck, + "void f(int xxx, int yyy); void g() { f(/*xxy=*/0, 0); }"); +} + +} // namespace test +} // namespace tidy +} // namespace clang