[clang] [LifetimeSafety] Fix 'clang::lifetimebound' ignored on template method definition (PR #178000)
Baranov Victor via cfe-commits
cfe-commits at lists.llvm.org
Mon Jan 26 11:52:27 PST 2026
https://github.com/vbvictor updated https://github.com/llvm/llvm-project/pull/178000
>From 2c564fc48fc4c0409ecd6664cfde4fb9d57b4acb Mon Sep 17 00:00:00 2001
From: Victor Baranov <bar.victor.2002 at gmail.com>
Date: Mon, 26 Jan 2026 20:27:33 +0300
Subject: [PATCH 1/2] [Lifetime] Fix lifetimebound ignored on template method
definition
---
.../LifetimeSafety/LifetimeAnnotations.cpp | 17 ++++++++----
.../Sema/warn-lifetime-analysis-nocfg.cpp | 26 +++++++++++++++++--
2 files changed, 36 insertions(+), 7 deletions(-)
diff --git a/clang/lib/Analysis/LifetimeSafety/LifetimeAnnotations.cpp b/clang/lib/Analysis/LifetimeSafety/LifetimeAnnotations.cpp
index 93c7a86d0a57c..dd925d2b8fe6e 100644
--- a/clang/lib/Analysis/LifetimeSafety/LifetimeAnnotations.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/LifetimeAnnotations.cpp
@@ -74,11 +74,18 @@ bool implicitObjectParamIsLifetimeBound(const FunctionDecl *FD) {
FD = getDeclWithMergedLifetimeBoundAttrs(FD);
// Attribute merging doesn't work well with attributes on function types (like
// 'this' param). We need to check all redeclarations.
- for (const FunctionDecl *Redecl : FD->redecls()) {
- const TypeSourceInfo *TSI = Redecl->getTypeSourceInfo();
- if (TSI && getLifetimeBoundAttrFromFunctionType(*TSI))
- return true;
- }
+ auto CheckRedecls = [](const FunctionDecl *F) {
+ return llvm::any_of(F->redecls(), [](const FunctionDecl *Redecl) {
+ const TypeSourceInfo *TSI = Redecl->getTypeSourceInfo();
+ return TSI && getLifetimeBoundAttrFromFunctionType(*TSI);
+ });
+ };
+
+ if (CheckRedecls(FD))
+ return true;
+ if (const FunctionDecl *Pattern = FD->getTemplateInstantiationPattern();
+ Pattern && CheckRedecls(Pattern))
+ return true;
return isNormalAssignmentOperator(FD);
}
diff --git a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
index 99a796c360a7f..605479d4db372 100644
--- a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
+++ b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
@@ -1252,6 +1252,24 @@ inline const char* StringTemplateSpecC<char>::data() const [[clang::lifetimeboun
return buffer;
}
+template<typename T>
+class MemberFuncsTpl {
+public:
+ // Template Version A: Attribute on declaration only
+ const T* memberA(const T& x [[clang::lifetimebound]]);
+ // Template Version B: Attribute on definition only
+ const T* memberB(const T& x);
+ // Template Version C: Attribute on BOTH declaration and definition
+ const T* memberC(const T& x [[clang::lifetimebound]]);
+};
+
+template<typename T>
+const T* MemberFuncsTpl<T>::memberA(const T& x) { return &x; }
+template<typename T>
+const T* MemberFuncsTpl<T>::memberB(const T& x [[clang::lifetimebound]]) { return &x; }
+template<typename T>
+const T* MemberFuncsTpl<T>::memberC(const T& x [[clang::lifetimebound]]) { return &x; }
+
void test() {
// Non-templated tests
const auto ptrA = StringA().data(); // Declaration-only attribute // expected-warning {{temporary whose address is used}}
@@ -1260,13 +1278,17 @@ void test() {
// Templated tests (generic templates)
const auto ptrTA = StringTemplateA<char>().data(); // Declaration-only attribute // expected-warning {{temporary whose address is used}}
- // FIXME: Definition is not instantiated until the end of TU. The attribute is not merged when this call is processed.
- const auto ptrTB = StringTemplateB<char>().data(); // Definition-only attribute
+ const auto ptrTB = StringTemplateB<char>().data(); // Definition-only attribute // expected-warning {{temporary whose address is used}}
const auto ptrTC = StringTemplateC<char>().data(); // Both have attribute // expected-warning {{temporary whose address is used}}
// Template specialization tests
const auto ptrTSA = StringTemplateSpecA<char>().data(); // Declaration-only attribute // expected-warning {{temporary whose address is used}}
const auto ptrTSB = StringTemplateSpecB<char>().data(); // Definition-only attribute // expected-warning {{temporary whose address is used}}
const auto ptrTSC = StringTemplateSpecC<char>().data(); // Both have attribute // expected-warning {{temporary whose address is used}}
+
+ MemberFuncsTpl<int> mtf;
+ const int* pTMA = mtf.memberA(1); // Declaration-only attribute // expected-warning {{temporary whose address is used}}
+ const int* pTMB = mtf.memberB(2); // Definition-only attribute // FIXME: Definition-only attribute
+ const int* pTMC = mtf.memberC(3); // Both have attribute // expected-warning {{temporary whose address is used}}
}
} // namespace GH175391
>From 5eb6ef191ec4d0c8d81d531bf094c7c674cbc3c6 Mon Sep 17 00:00:00 2001
From: Victor Baranov <bar.victor.2002 at gmail.com>
Date: Mon, 26 Jan 2026 22:51:56 +0300
Subject: [PATCH 2/2] add new case
---
clang/test/Sema/warn-lifetime-safety.cpp | 43 +++++++++++++++++++++++-
1 file changed, 42 insertions(+), 1 deletion(-)
diff --git a/clang/test/Sema/warn-lifetime-safety.cpp b/clang/test/Sema/warn-lifetime-safety.cpp
index a3ff4cd99288b..2bad0960e7fed 100644
--- a/clang/test/Sema/warn-lifetime-safety.cpp
+++ b/clang/test/Sema/warn-lifetime-safety.cpp
@@ -1,5 +1,5 @@
// RUN: %clang_cc1 -fsyntax-only -Wlifetime-safety -Wno-dangling -verify=expected,function %s
-// RUN: %clang_cc1 -fsyntax-only -flifetime-safety-inference -fexperimental-lifetime-safety-tu-analysis -Wlifetime-safety -Wno-dangling -verify %s
+// RUN: %clang_cc1 -fsyntax-only -flifetime-safety-inference -fexperimental-lifetime-safety-tu-analysis -Wlifetime-safety -Wno-dangling -verify=expected,inference %s
#include "Inputs/lifetime-analysis.h"
@@ -1575,3 +1575,44 @@ std::string_view& refViewMemberReturnView2(RefMember a) { return a.view; } // ex
std::string_view refViewMemberReturnRefView1(RefMember a) { return a.view_ref; }
std::string_view& refViewMemberReturnRefView2(RefMember a) { return a.view_ref; }
} // namespace field_access
+
+namespace attr_on_template_params {
+struct MyObj {
+ ~MyObj();
+};
+
+template <typename T>
+struct MemberFuncsTpl {
+ ~MemberFuncsTpl();
+ // Template Version A: Attribute on declaration only
+ const T* memberA(const T& x [[clang::lifetimebound]]);
+ // Template Version B: Attribute on definition only
+ const T* memberB(const T& x);
+ // Template Version C: Attribute on BOTH declaration and definition
+ const T* memberC(const T& x [[clang::lifetimebound]]);
+};
+
+template <typename T>
+const T* MemberFuncsTpl<T>::memberA(const T& x) {
+ return &x;
+}
+template <typename T>
+const T* MemberFuncsTpl<T>::memberB(const T& x [[clang::lifetimebound]]) {
+ return &x;
+}
+template <typename T>
+const T* MemberFuncsTpl<T>::memberC(const T& x [[clang::lifetimebound]]) {
+ return &x;
+}
+
+void test() {
+ MemberFuncsTpl<MyObj> mtf;
+ const MyObj* pTMA = mtf.memberA(MyObj()); // expected-warning {{object whose reference is captured does not live long enough}} // expected-note {{destroyed here}}
+ const MyObj* pTMB = mtf.memberB(MyObj()); // inference-warning {{object whose reference is captured does not live long enough}} // inference-note {{destroyed here}}
+ const MyObj* pTMC = mtf.memberC(MyObj()); // expected-warning {{object whose reference is captured does not live long enough}} // expected-note {{destroyed here}}
+ (void)pTMA; // expected-note {{later used here}}
+ (void)pTMB; // inference-note {{later used here}}
+ (void)pTMC; // expected-note {{later used here}}
+}
+
+} // namespace attr_on_template_params
\ No newline at end of file
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