[clang-tools-extra] c4f83a0 - [clang-tidy] new check misc-use-internal-linkage (#90830)
via cfe-commits
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Fri Jun 7 15:46:43 PDT 2024
Author: Congcong Cai
Date: 2024-06-08T06:46:39+08:00
New Revision: c4f83a004bf35bfc46fe89111fdca750bbc724da
URL: https://github.com/llvm/llvm-project/commit/c4f83a004bf35bfc46fe89111fdca750bbc724da
DIFF: https://github.com/llvm/llvm-project/commit/c4f83a004bf35bfc46fe89111fdca750bbc724da.diff
LOG: [clang-tidy] new check misc-use-internal-linkage (#90830)
Add new check misc-use-internal-linkage to detect variable and function
can be marked as static.
---------
Co-authored-by: Danny Mösch <danny.moesch at icloud.com>
Added:
clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.cpp
clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.h
clang-tools-extra/docs/clang-tidy/checks/misc/use-internal-linkage.rst
clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func.h
clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_cpp.inc
clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_h.inc
clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/var.h
clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-func.cpp
clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-var.cpp
Modified:
clang-tools-extra/clang-tidy/misc/CMakeLists.txt
clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
clang-tools-extra/docs/ReleaseNotes.rst
clang-tools-extra/docs/clang-tidy/checks/list.rst
Removed:
################################################################################
diff --git a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
index 36fcd8fc1b277..1c1d3b836ea1b 100644
--- a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
@@ -41,6 +41,7 @@ add_clang_library(clangTidyMiscModule
UnusedParametersCheck.cpp
UnusedUsingDeclsCheck.cpp
UseAnonymousNamespaceCheck.cpp
+ UseInternalLinkageCheck.cpp
LINK_LIBS
clangTidy
diff --git a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
index d8a88324ee63e..54bcebca7e186 100644
--- a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
@@ -31,6 +31,7 @@
#include "UnusedParametersCheck.h"
#include "UnusedUsingDeclsCheck.h"
#include "UseAnonymousNamespaceCheck.h"
+#include "UseInternalLinkageCheck.h"
namespace clang::tidy {
namespace misc {
@@ -78,6 +79,8 @@ class MiscModule : public ClangTidyModule {
"misc-unused-using-decls");
CheckFactories.registerCheck<UseAnonymousNamespaceCheck>(
"misc-use-anonymous-namespace");
+ CheckFactories.registerCheck<UseInternalLinkageCheck>(
+ "misc-use-internal-linkage");
}
};
diff --git a/clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.cpp b/clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.cpp
new file mode 100644
index 0000000000000..70d0281df28fa
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.cpp
@@ -0,0 +1,95 @@
+//===--- UseInternalLinkageCheck.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 "UseInternalLinkageCheck.h"
+#include "../utils/FileExtensionsUtils.h"
+#include "clang/AST/Decl.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/ASTMatchers/ASTMatchersMacros.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/Specifiers.h"
+#include "llvm/ADT/STLExtras.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::misc {
+
+namespace {
+
+AST_MATCHER(Decl, isFirstDecl) { return Node.isFirstDecl(); }
+
+static bool isInMainFile(SourceLocation L, SourceManager &SM,
+ const FileExtensionsSet &HeaderFileExtensions) {
+ for (;;) {
+ if (utils::isSpellingLocInHeaderFile(L, SM, HeaderFileExtensions))
+ return false;
+ if (SM.isInMainFile(L))
+ return true;
+ // not in header file but not in main file
+ L = SM.getIncludeLoc(SM.getFileID(L));
+ if (L.isValid())
+ continue;
+ // Conservative about the unknown
+ return false;
+ }
+}
+
+AST_MATCHER_P(Decl, isAllRedeclsInMainFile, FileExtensionsSet,
+ HeaderFileExtensions) {
+ return llvm::all_of(Node.redecls(), [&](const Decl *D) {
+ return isInMainFile(D->getLocation(),
+ Finder->getASTContext().getSourceManager(),
+ HeaderFileExtensions);
+ });
+}
+
+AST_POLYMORPHIC_MATCHER(isExternStorageClass,
+ AST_POLYMORPHIC_SUPPORTED_TYPES(FunctionDecl,
+ VarDecl)) {
+ return Node.getStorageClass() == SC_Extern;
+}
+
+} // namespace
+
+void UseInternalLinkageCheck::registerMatchers(MatchFinder *Finder) {
+ auto Common =
+ allOf(isFirstDecl(), isAllRedeclsInMainFile(HeaderFileExtensions),
+ unless(anyOf(
+ // 1. internal linkage
+ isStaticStorageClass(), isInAnonymousNamespace(),
+ // 2. explicit external linkage
+ isExternStorageClass(), isExternC(),
+ // 3. template
+ isExplicitTemplateSpecialization(),
+ // 4. friend
+ hasAncestor(friendDecl()))));
+ Finder->addMatcher(
+ functionDecl(Common, unless(cxxMethodDecl()), unless(isMain()))
+ .bind("fn"),
+ this);
+ Finder->addMatcher(varDecl(Common, hasGlobalStorage()).bind("var"), this);
+}
+
+static constexpr StringRef Message =
+ "%0 %1 can be made static or moved into an anonymous namespace "
+ "to enforce internal linkage";
+
+void UseInternalLinkageCheck::check(const MatchFinder::MatchResult &Result) {
+ if (const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>("fn")) {
+ diag(FD->getLocation(), Message) << "function" << FD;
+ return;
+ }
+ if (const auto *VD = Result.Nodes.getNodeAs<VarDecl>("var")) {
+ diag(VD->getLocation(), Message) << "variable" << VD;
+ return;
+ }
+ llvm_unreachable("");
+}
+
+} // namespace clang::tidy::misc
diff --git a/clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.h b/clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.h
new file mode 100644
index 0000000000000..a3c1c33965903
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/UseInternalLinkageCheck.h
@@ -0,0 +1,38 @@
+//===--- UseInternalLinkageCheck.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_MISC_USEINTERNALLINKAGECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_USEINTERNALLINKAGECHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang::tidy::misc {
+
+/// Detects variables and functions that can be marked as static or moved into
+/// an anonymous namespace to enforce internal linkage.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc/use-internal-linkage.html
+class UseInternalLinkageCheck : public ClangTidyCheck {
+public:
+ UseInternalLinkageCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ HeaderFileExtensions(Context->getHeaderFileExtensions()) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ std::optional<TraversalKind> getCheckTraversalKind() const override {
+ return TK_IgnoreUnlessSpelledInSource;
+ }
+
+private:
+ FileExtensionsSet HeaderFileExtensions;
+};
+
+} // namespace clang::tidy::misc
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_USEINTERNALLINKAGECHECK_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index da30aceb8d49d..277a6e75da2ac 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -148,6 +148,12 @@ New checks
to reading out-of-bounds data due to inadequate or incorrect string null
termination.
+- New :doc:`misc-use-internal-linkage
+ <clang-tidy/checks/misc/use-internal-linkage>` check.
+
+ Detects variables and functions that can be marked as static or moved into
+ an anonymous namespace to enforce internal linkage.
+
- New :doc:`modernize-min-max-use-initializer-list
<clang-tidy/checks/modernize/min-max-use-initializer-list>` check.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
index 85e4f0352ac22..87d3db20f7684 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -267,6 +267,7 @@ Clang-Tidy Checks
:doc:`misc-unused-parameters <misc/unused-parameters>`, "Yes"
:doc:`misc-unused-using-decls <misc/unused-using-decls>`, "Yes"
:doc:`misc-use-anonymous-namespace <misc/use-anonymous-namespace>`,
+ :doc:`misc-use-internal-linkage <misc/use-internal-linkage>`,
:doc:`modernize-avoid-bind <modernize/avoid-bind>`, "Yes"
:doc:`modernize-avoid-c-arrays <modernize/avoid-c-arrays>`,
:doc:`modernize-concat-nested-namespaces <modernize/concat-nested-namespaces>`, "Yes"
diff --git a/clang-tools-extra/docs/clang-tidy/checks/misc/use-internal-linkage.rst b/clang-tools-extra/docs/clang-tidy/checks/misc/use-internal-linkage.rst
new file mode 100644
index 0000000000000..e8e43a1fb3d63
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/misc/use-internal-linkage.rst
@@ -0,0 +1,27 @@
+.. title:: clang-tidy - misc-use-internal-linkage
+
+misc-use-internal-linkage
+=========================
+
+Detects variables and functions that can be marked as static or moved into
+an anonymous namespace to enforce internal linkage.
+
+Static functions and variables are scoped to a single file. Marking functions
+and variables as static helps to better remove dead code. In addition, it gives
+the compiler more information and allows for more aggressive optimizations.
+
+Example:
+
+.. code-block:: c++
+
+ int v1; // can be marked as static
+
+ void fn1(); // can be marked as static
+
+ namespace {
+ // already in anonymous namespace
+ int v2;
+ void fn2();
+ }
+ // already declared as extern
+ extern int v2;
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func.h b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func.h
new file mode 100644
index 0000000000000..0f2b576a126c4
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func.h
@@ -0,0 +1,5 @@
+#pragma once
+
+void func_header();
+
+#include "func_h.inc"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_cpp.inc b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_cpp.inc
new file mode 100644
index 0000000000000..97e026f0116e9
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_cpp.inc
@@ -0,0 +1 @@
+void func_cpp_inc();
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_h.inc b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_h.inc
new file mode 100644
index 0000000000000..1130f710edd7c
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/func_h.inc
@@ -0,0 +1 @@
+void func_h_inc();
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/var.h b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/var.h
new file mode 100644
index 0000000000000..37e4cfbafff14
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/Inputs/use-internal-linkage/var.h
@@ -0,0 +1,3 @@
+#pragma once
+
+extern int gloabl_header;
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-func.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-func.cpp
new file mode 100644
index 0000000000000..c6c513fe0b0c0
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-func.cpp
@@ -0,0 +1,37 @@
+// RUN: %check_clang_tidy %s misc-use-internal-linkage %t -- -- -I%S/Inputs/use-internal-linkage
+
+#include "func.h"
+
+void func() {}
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: function 'func'
+
+template<class T>
+void func_template() {}
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: function 'func_template'
+
+void func_cpp_inc();
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: function 'func_cpp_inc'
+
+#include "func_cpp.inc"
+
+void func_h_inc();
+
+struct S {
+ void method();
+};
+void S::method() {}
+
+void func_header();
+extern void func_extern();
+static void func_static();
+namespace {
+void func_anonymous_ns();
+} // namespace
+
+int main(int argc, const char*argv[]) {}
+
+extern "C" {
+void func_extern_c_1() {}
+}
+
+extern "C" void func_extern_c_2() {}
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-var.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-var.cpp
new file mode 100644
index 0000000000000..bd5ef5431de6c
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/use-internal-linkage-var.cpp
@@ -0,0 +1,40 @@
+// RUN: %check_clang_tidy %s misc-use-internal-linkage %t -- -- -I%S/Inputs/use-internal-linkage
+
+#include "var.h"
+
+int global;
+// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: variable 'global'
+
+template<class T>
+T global_template;
+// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: variable 'global_template'
+
+int gloabl_header;
+
+extern int global_extern;
+
+static int global_static;
+
+namespace {
+static int global_anonymous_ns;
+namespace NS {
+static int global_anonymous_ns;
+}
+}
+
+static void f(int para) {
+ int local;
+ static int local_static;
+}
+
+struct S {
+ int m1;
+ static int m2;
+};
+int S::m2;
+
+extern "C" {
+int global_in_extern_c_1;
+}
+
+extern "C" int global_in_extern_c_2;
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