[clang-tools-extra] [clang-tidy] Teach `cppcoreguidelines-interfaces-global-init` about `constinit` (PR #148334)
Victor Chernyakin via cfe-commits
cfe-commits at lists.llvm.org
Fri Jul 11 23:09:35 PDT 2025
https://github.com/localspook updated https://github.com/llvm/llvm-project/pull/148334
>From e6b9c9ab548986d26fe24a91ab360e7c0363817d Mon Sep 17 00:00:00 2001
From: Victor Chernyakin <chernyakin.victor.j at outlook.com>
Date: Fri, 11 Jul 2025 21:09:22 -0700
Subject: [PATCH 1/2] [clang-tidy] Teach
`cppcoreguidelines-interfaces-global-init` about `constinit`
---
.../InterfacesGlobalInitCheck.cpp | 2 +-
clang-tools-extra/docs/ReleaseNotes.rst | 4 +++
.../interfaces-global-init.cpp | 28 +++++++++++++++++--
3 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/InterfacesGlobalInitCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/InterfacesGlobalInitCheck.cpp
index e8a2e7b8ef86d..e9f0bd98cad16 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/InterfacesGlobalInitCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/InterfacesGlobalInitCheck.cpp
@@ -19,7 +19,7 @@ void InterfacesGlobalInitCheck::registerMatchers(MatchFinder *Finder) {
hasDeclContext(anyOf(translationUnitDecl(), // Global scope.
namespaceDecl(), // Namespace scope.
recordDecl())), // Class scope.
- unless(isConstexpr()));
+ unless(isConstexpr()), unless(isConstinit()));
const auto ReferencesUndefinedGlobalVar = declRefExpr(hasDeclaration(
varDecl(GlobalVarDecl, unless(isDefinition())).bind("referencee")));
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index ad869265a2db5..bff7cfa4fe525 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -212,6 +212,10 @@ Changes in existing checks
<clang-tidy/checks/cppcoreguidelines/avoid-goto>` check by adding the option
`IgnoreMacros` to ignore ``goto`` labels defined in macros.
+- Improved :doc:`cppcoreguidelines-interfaces-global-init
+ <clang-tidy/checks/cppcoreguidelines/interfaces-global-init>` check by
+ fixing false positives on uses of ``constinit`` variables.
+
- Improved :doc:`cppcoreguidelines-missing-std-forward
<clang-tidy/checks/cppcoreguidelines/missing-std-forward>` check by adding a
flag to specify the function used for forwarding instead of ``std::forward``.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp
index 51f79e522c0ca..38d02c6a7f186 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy %s cppcoreguidelines-interfaces-global-init %t
+// RUN: %check_clang_tidy -std=c++20 %s cppcoreguidelines-interfaces-global-init %t
constexpr int makesInt() { return 3; }
constexpr int takesInt(int i) { return i + 1; }
@@ -14,11 +14,19 @@ static int GlobalScopeBadInit3 = takesIntPtr(&ExternGlobal);
static int GlobalScopeBadInit4 = 3 * (ExternGlobal + 2);
// CHECK-MESSAGES: [[@LINE-1]]:12: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'ExternGlobal'
+extern constinit int ExternConstinitGlobal;
+static int GlobalScopeConstinit1 = ExternConstinitGlobal;
+static int GlobalScopeConstinit2 = takesInt(ExternConstinitGlobal);
+static int GlobalScopeConstinit3 = takesIntPtr(&ExternConstinitGlobal);
+static int GlobalScopeConstinit4 = 3 * (ExternConstinitGlobal + 2);
+
namespace ns {
static int NamespaceScope = makesInt();
static int NamespaceScopeBadInit = takesInt(ExternGlobal);
// CHECK-MESSAGES: [[@LINE-1]]:12: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'ExternGlobal'
+static int NamespaceScopeConstinit = takesInt(ExternConstinitGlobal);
+
struct A {
static int ClassScope;
static int ClassScopeBadInit;
@@ -29,6 +37,15 @@ int A::ClassScopeBadInit = takesInt(ExternGlobal);
static int FromClassBadInit = takesInt(A::ClassScope);
// CHECK-MESSAGES: [[@LINE-1]]:12: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'ClassScope'
+
+struct B {
+ static constinit int ClassScopeConstinit;
+ static int ClassScopeFromConstinit;
+};
+
+int B::ClassScopeFromConstinit = takesInt(ExternConstinitGlobal);
+static int FromClassScopeConstinit = takesInt(B::ClassScopeConstinit);
+
} // namespace ns
// "const int B::I;" is fine, it just ODR-defines B::I. See [9.4.3] Static
@@ -42,6 +59,14 @@ const int B1::J;
// CHECK-MESSAGES: [[@LINE-1]]:15: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'I'
const int B1::I;
+class D {
+ static const constinit int I = 0;
+ static const int J = I;
+};
+
+const int D::J;
+const int D::I;
+
void f() {
// This is fine, it's executed after dynamic initialization occurs.
static int G = takesInt(ExternGlobal);
@@ -81,4 +106,3 @@ class B2 {
};
const int B2::I;
const int B2::J;
-
>From 2a30a82c553b7ece9fc005a98c58187a0333b9a8 Mon Sep 17 00:00:00 2001
From: Victor Chernyakin <chernyakin.victor.j at outlook.com>
Date: Fri, 11 Jul 2025 23:09:05 -0700
Subject: [PATCH 2/2] Reenable for all modes
---
.../cppcoreguidelines/interfaces-global-init.cpp | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp
index 38d02c6a7f186..8ce42994e1172 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/interfaces-global-init.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy -std=c++20 %s cppcoreguidelines-interfaces-global-init %t
+// RUN: %check_clang_tidy %s cppcoreguidelines-interfaces-global-init %t
constexpr int makesInt() { return 3; }
constexpr int takesInt(int i) { return i + 1; }
@@ -14,18 +14,22 @@ static int GlobalScopeBadInit3 = takesIntPtr(&ExternGlobal);
static int GlobalScopeBadInit4 = 3 * (ExternGlobal + 2);
// CHECK-MESSAGES: [[@LINE-1]]:12: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'ExternGlobal'
+#if __cplusplus >= 202002L
extern constinit int ExternConstinitGlobal;
static int GlobalScopeConstinit1 = ExternConstinitGlobal;
static int GlobalScopeConstinit2 = takesInt(ExternConstinitGlobal);
static int GlobalScopeConstinit3 = takesIntPtr(&ExternConstinitGlobal);
static int GlobalScopeConstinit4 = 3 * (ExternConstinitGlobal + 2);
+#endif
namespace ns {
static int NamespaceScope = makesInt();
static int NamespaceScopeBadInit = takesInt(ExternGlobal);
// CHECK-MESSAGES: [[@LINE-1]]:12: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'ExternGlobal'
+#if __cplusplus >= 202002L
static int NamespaceScopeConstinit = takesInt(ExternConstinitGlobal);
+#endif
struct A {
static int ClassScope;
@@ -38,6 +42,7 @@ int A::ClassScopeBadInit = takesInt(ExternGlobal);
static int FromClassBadInit = takesInt(A::ClassScope);
// CHECK-MESSAGES: [[@LINE-1]]:12: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'ClassScope'
+#if __cplusplus >= 202002L
struct B {
static constinit int ClassScopeConstinit;
static int ClassScopeFromConstinit;
@@ -45,6 +50,7 @@ struct B {
int B::ClassScopeFromConstinit = takesInt(ExternConstinitGlobal);
static int FromClassScopeConstinit = takesInt(B::ClassScopeConstinit);
+#endif
} // namespace ns
@@ -59,6 +65,7 @@ const int B1::J;
// CHECK-MESSAGES: [[@LINE-1]]:15: warning: initializing non-local variable with non-const expression depending on uninitialized non-local variable 'I'
const int B1::I;
+#if __cplusplus >= 202002L
class D {
static const constinit int I = 0;
static const int J = I;
@@ -66,6 +73,7 @@ class D {
const int D::J;
const int D::I;
+#endif
void f() {
// This is fine, it's executed after dynamic initialization occurs.
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