[clang-tools-extra] [clang-tidy]suggest use `std::span` as replacement of c array in C++20 for modernize-avoid-c-arrays (PR #108555)
Congcong Cai via cfe-commits
cfe-commits at lists.llvm.org
Fri Sep 13 08:08:15 PDT 2024
https://github.com/HerrCai0907 updated https://github.com/llvm/llvm-project/pull/108555
>From 35742b5f2f085b8f6626456cd0d21ebecbe8f831 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcong.cai at bmw.com>
Date: Thu, 12 Sep 2024 23:11:51 +0800
Subject: [PATCH 1/2] [clang-tidy]suggest use `std::span` as replacement of c
array in C++20 for modernize-avoid-c-arrays
---
.../modernize/AvoidCArraysCheck.cpp | 26 ++++++++++++++++---
clang-tools-extra/docs/ReleaseNotes.rst | 4 +++
.../modernize/avoid-c-arrays-c++20.cpp | 7 +++++
.../modernize/avoid-c-arrays-ignores-main.cpp | 6 ++---
.../avoid-c-arrays-ignores-strings.cpp | 4 +--
.../avoid-c-arrays-ignores-three-arg-main.cpp | 10 +++----
.../checkers/modernize/avoid-c-arrays.cpp | 4 +--
7 files changed, 46 insertions(+), 15 deletions(-)
create mode 100644 clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp
diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index 89790ea70cf229..9fd0259ed1aacf 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;
@@ -38,6 +39,13 @@ AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) {
return FD ? FD->isMain() : false;
}
+AST_MATCHER_P(clang::TypeLoc, alwaysTrue,
+ clang::ast_matchers::internal::Matcher<clang::TypeLoc>,
+ InnerMatcher) {
+ InnerMatcher.matches(Node, Finder, Builder);
+ return true;
+}
+
} // namespace
AvoidCArraysCheck::AvoidCArraysCheck(StringRef Name, ClangTidyContext *Context)
@@ -60,6 +68,7 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
typeLoc(hasValidBeginLoc(), hasType(arrayType()),
+ alwaysTrue(hasParent(parmVarDecl().bind("param_decl"))),
unless(anyOf(hasParent(parmVarDecl(isArgvOfMain())),
hasParent(varDecl(isExternC())),
hasParent(fieldDecl(
@@ -72,11 +81,22 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc");
-
+ bool const IsInParam =
+ Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr;
+ const bool IsVLA = ArrayType->getTypePtr()->isVariableArrayType();
+ // in function parameter, we also don't know the size of IncompleteArrayType.
+ const bool IsUnknownSize =
+ IsVLA || (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam);
+ enum class RecommendType { Array, Vector, Span };
+ const RecommendType RecommendType =
+ (IsInParam && Result.Context->getLangOpts().CPlusPlus20)
+ ? RecommendType::Span
+ : IsUnknownSize ? RecommendType::Vector
+ : RecommendType::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();
+ "%select{std::array<>|std::vector<>|std::span<>}1 instead")
+ << IsVLA << static_cast<int>(RecommendType);
}
} // namespace clang::tidy::modernize
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 1ad8cedc902cb5..c5a2b3c36d130f 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -111,6 +111,10 @@ Changes in existing checks
<clang-tidy/checks/bugprone/casting-through-void>` check to suggest replacing
the offending code with ``reinterpret_cast``, to more clearly express intent.
+- Improved :doc:`modernize-avoid-c-arrays
+ <clang-tidy/checks/modernize/avoid-c-arrays>` check to suggest use std::span
+ as replacement of c array in 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/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..a9298245feaaeb
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/avoid-c-arrays-c++20.cpp
@@ -0,0 +1,7 @@
+// RUN: %check_clang_tidy -std=c++20 %s modernize-avoid-c-arrays %t
+
+int foo(int data[], int size) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: 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
+}
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..f833a85164f333 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::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::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..c8277feb3958bf 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::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..ae2e0bc9c10035 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::vector<> instead
+ // CHECK-MESSAGES: :[[@LINE-2]]:38: warning: do not declare C-style arrays, use 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::vector<> instead
+ // CHECK-MESSAGES: :[[@LINE-2]]:46: warning: do not declare C-style arrays, use 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..15fc4d4954c867 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::vector<> instead [modernize-avoid-c-arrays]
>From 3912ba85d649730567c29bda91c735d3b4301186 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Fri, 13 Sep 2024 22:28:41 +0800
Subject: [PATCH 2/2] recommend std::array for fixed size parameter
---
.../modernize/AvoidCArraysCheck.cpp | 20 ++++++++++---------
.../modernize/avoid-c-arrays-c++20.cpp | 8 ++++++--
2 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
index 9fd0259ed1aacf..5db9df41ef2cb9 100644
--- a/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp
@@ -81,18 +81,20 @@ void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc");
- bool const IsInParam =
+ const bool IsInParam =
Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr;
const bool IsVLA = ArrayType->getTypePtr()->isVariableArrayType();
- // in function parameter, we also don't know the size of IncompleteArrayType.
- const bool IsUnknownSize =
- IsVLA || (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam);
enum class RecommendType { Array, Vector, Span };
- const RecommendType RecommendType =
- (IsInParam && Result.Context->getLangOpts().CPlusPlus20)
- ? RecommendType::Span
- : IsUnknownSize ? RecommendType::Vector
- : RecommendType::Array;
+ RecommendType RecommendType = RecommendType::Array;
+ if (IsVLA) {
+ RecommendType = RecommendType::Vector;
+ } else if (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam) {
+ // in function parameter, we also don't know the size of
+ // IncompleteArrayType.
+ RecommendType = Result.Context->getLangOpts().CPlusPlus20
+ ? RecommendType::Span
+ : RecommendType::Vector;
+ }
diag(ArrayType->getBeginLoc(),
"do not declare %select{C-style|C VLA}0 arrays, use "
"%select{std::array<>|std::vector<>|std::span<>}1 instead")
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
index a9298245feaaeb..e53cfeba0e4601 100644
--- 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
@@ -1,7 +1,11 @@
// RUN: %check_clang_tidy -std=c++20 %s modernize-avoid-c-arrays %t
-int foo(int data[], int size) {
- // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: do not declare C-style arrays, use std::span<> instead
+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
+}
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