[clang] 3278ff7 - [LifetimeSafety] Fix 'clang::lifetimebound' ignored on template method definition (#178000)

[via cfe-commits]

Author: Baranov Victor
Date: 2026-01-27T10:17:53Z
New Revision: 3278ff7a4fa8f90c60081c88f3d441cf1468e84c

URL: https://github.com/llvm/llvm-project/commit/3278ff7a4fa8f90c60081c88f3d441cf1468e84c
DIFF: https://github.com/llvm/llvm-project/commit/3278ff7a4fa8f90c60081c88f3d441cf1468e84c.diff

LOG: [LifetimeSafety] Fix 'clang::lifetimebound' ignored on template method definition (#178000)

Closes https://github.com/llvm/llvm-project/issues/177798.

Same pattern with `getTemplateInstantiationPattern()` for attrs checking
is already used in other LLVM places, e.g.:


https://github.com/llvm/llvm-project/blob/b19238d0d0a7d026de8e2ad28775db57afccb01d/clang/lib/CodeGen/CodeGenModule.cpp#L2830-L2839

Added: 
    

Modified: 
    clang/lib/Analysis/LifetimeSafety/LifetimeAnnotations.cpp
    clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
    clang/test/Sema/warn-lifetime-safety.cpp

Removed: 
    


################################################################################
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..29554f5a98029 100644
--- a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
+++ b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
@@ -1260,8 +1260,7 @@ 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

diff  --git a/clang/test/Sema/warn-lifetime-safety.cpp b/clang/test/Sema/warn-lifetime-safety.cpp
index a3ff4cd99288b..d6064dea9e545 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,tu %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()); // tu-warning {{object whose reference is captured does not live long enough}} // tu-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; // tu-note {{later used here}}
+  (void)pTMC; // expected-note {{later used here}}
+}
+
+} // namespace attr_on_template_params