Author: Congcong Cai Date: 2024-09-18T08:03:06+08:00 New Revision: 785624b28237bb75d4fa3b8e4219a5448b90eaac
URL: https://github.com/llvm/llvm-project/commit/785624b28237bb75d4fa3b8e4219a5448b90eaac DIFF: https://github.com/llvm/llvm-project/commit/785624b28237bb75d4fa3b8e4219a5448b90eaac.diff LOG: [clang-tidy]suggest use `std::span` as replacement of c array in C++20 for modernize-avoid-c-arrays (#108555) The incompleted C-Array in parameter does not own memory. Instead, It is equivalent to pointer. So we should not use `std::array` as recommended modern C++ replacement, but use `std::vector` and `std::span` in C++20 Added: clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp Modified: clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp clang-tools-extra/docs/ReleaseNotes.rst clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp Removed: ################################################################################ diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp index 89790ea70cf229..98778192dbd3ae 100644 --- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp +++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp @@ -9,6 +9,7 @@ #include "AvoidCArraysCheck.h" #include "clang/AST/ASTContext.h" #include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" using namespace clang::ast_matchers; @@ -60,6 +61,7 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) { Finder->addMatcher( typeLoc(hasValidBeginLoc(), hasType(arrayType()), + optionally(hasParent(parmVarDecl().bind("param_decl"))), unless(anyOf(hasParent(parmVarDecl(isArgvOfMain())), hasParent(varDecl(isExternC())), hasParent(fieldDecl( @@ -72,11 +74,28 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) { void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) { const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc"); - + const bool IsInParam = + Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr; + const bool IsVLA = ArrayType->getTypePtr()->isVariableArrayType(); + enum class RecommendType { Array, Vector, Span }; + llvm::SmallVector<const char *> RecommendTypes{}; + if (IsVLA) { + RecommendTypes.push_back("std::vector<>"); + } else if (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam) { + // in function parameter, we also don't know the size of + // IncompleteArrayType. + if (Result.Context->getLangOpts().CPlusPlus20) + RecommendTypes.push_back("std::span<>"); + else { + RecommendTypes.push_back("std::array<>"); + RecommendTypes.push_back("std::vector<>"); + } + } else { + RecommendTypes.push_back("std::array<>"); + } diag(ArrayType->getBeginLoc(), - "do not declare %select{C-style|C VLA}0 arrays, use " - "%select{std::array<>|std::vector<>}0 instead") - << ArrayType->getTypePtr()->isVariableArrayType(); + "do not declare %select{C-style|C VLA}0 arrays, use %1 instead") + << IsVLA << llvm::join(RecommendTypes, " or "); } } // namespace clang::tidy::modernize diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst index 79501b563b4e22..2370b594d22269 100644 --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -137,6 +137,11 @@ Changes in existing checks <clang-tidy/checks/misc/definitions-in-headers>` check by rewording the diagnostic note that suggests adding ``inline``. +- Improved :doc:`modernize-avoid-c-arrays + <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest using ``std::span`` + as a replacement for parameters of incomplete C array type in C++20 and + ``std::array`` or ``std::vector`` before C++20. + - Improved :doc:`modernize-use-std-format <clang-tidy/checks/modernize/use-std-format>` check to support replacing member function calls too. diff --git a/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst b/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst index 8f13ca4466a310..2d72352989ab94 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/modernize/avoid-c-arrays.rst @@ -10,6 +10,9 @@ modernize-avoid-c-arrays Finds C-style array types and recommend to use ``std::array<>`` / ``std::vector<>``. All types of C arrays are diagnosed. +For incomplete C-style array types appeared in parameters, It would be better to +use ``std::span`` / ``gsl::span`` as replacement. + However, fix-it are potentially dangerous in header files and are therefore not emitted right now. diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp new file mode 100644 index 00000000000000..e53cfeba0e4601 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp @@ -0,0 +1,11 @@ +// RUN: %check_clang_tidy -std=c++20 %s modernize-avoid-c-arrays %t + +int f1(int data[], int size) { + // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: do not declare C-style arrays, use std::span<> instead + int f4[] = {1, 2}; + // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead +} + +int f2(int data[100]) { + // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: do not declare C-style arrays, use std::array<> instead +} diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp index 6549422f393aaa..ad12b3d6f95b91 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-main.cpp @@ -1,7 +1,7 @@ -// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t +// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t int not_main(int argc, char *argv[]) { - // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> instead + // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead int f4[] = {1, 2}; // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead } @@ -11,7 +11,7 @@ int main(int argc, char *argv[]) { // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead auto not_main = [](int argc, char *argv[]) { - // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> instead + // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead int f6[] = {1, 2}; // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not declare C-style arrays, use std::array<> instead }; diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp index f6d64848f9e3a0..b607068f5b7c9c 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-strings.cpp @@ -1,4 +1,4 @@ -// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t -- \ +// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t -- \ // RUN: -config='{CheckOptions: { modernize-avoid-c-arrays.AllowStringArrays: true }}' const char name[] = "name"; @@ -6,4 +6,4 @@ const char array[] = {'n', 'a', 'm', 'e', '\0'}; // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays] void takeCharArray(const char name[]); -// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays] +// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead [modernize-avoid-c-arrays] diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp index 22a4016f79f4da..c04edf2b5aea08 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-ignores-three-arg-main.cpp @@ -1,8 +1,8 @@ -// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t +// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t int not_main(int argc, char *argv[], char *argw[]) { - // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> instead - // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: do not declare C-style arrays, use std::array<> instead + // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead + // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead int f4[] = {1, 2}; // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead } @@ -12,8 +12,8 @@ int main(int argc, char *argv[], char *argw[]) { // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: do not declare C-style arrays, use std::array<> instead auto not_main = [](int argc, char *argv[], char *argw[]) { - // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> instead - // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: do not declare C-style arrays, use std::array<> instead + // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead + // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead int f6[] = {1, 2}; // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: do not declare C-style arrays, use std::array<> instead }; diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp index ce99f0821b2230..b0aaa4962a8351 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays.cpp @@ -1,4 +1,4 @@ -// RUN: %check_clang_tidy %s modernize-avoid-c-arrays %t +// RUN: %check_clang_tidy -std=c++17 %s modernize-avoid-c-arrays %t int a[] = {1, 2}; // CHECK-MESSAGES: :[[@LINE-1]]:1: warning: do not declare C-style arrays, use std::array<> instead @@ -91,4 +91,4 @@ const char name[] = "Some string"; // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays] void takeCharArray(const char name[]); -// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> instead [modernize-avoid-c-arrays] +// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: do not declare C-style arrays, use std::array<> or std::vector<> instead [modernize-avoid-c-arrays] _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
