[clang] [clang] Fix false positive regression for lifetime analysis warning. (PR #127460)

[Haojian Wu via cfe-commits]

https://github.com/hokein updated 
https://github.com/llvm/llvm-project/pull/127460

>From 3601ae837475da3c473f5be9c17687c439495ded Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein...@gmail.com>
Date: Mon, 17 Feb 2025 10:08:14 +0100
Subject: [PATCH 1/3] [clang] Fix false positive regression for lifetime
 analysis warning.

---
 clang/lib/Sema/CheckExprLifetime.cpp          |  5 ++--
 clang/test/Sema/Inputs/lifetime-analysis.h    |  2 ++
 .../Sema/warn-lifetime-analysis-nocfg.cpp     | 24 +++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/CheckExprLifetime.cpp 
b/clang/lib/Sema/CheckExprLifetime.cpp
index 8963cad86dbca..3e0867343ccee 100644
--- a/clang/lib/Sema/CheckExprLifetime.cpp
+++ b/clang/lib/Sema/CheckExprLifetime.cpp
@@ -1239,11 +1239,12 @@ static AnalysisResult analyzePathForGSLPointer(const 
IndirectLocalPath &Path,
     }
     // Check the return type, e.g.
     //   const GSLOwner& func(const Foo& foo [[clang::lifetimebound]])
+    //   GSLOwner* func(cosnt Foo& foo [[clang::lifetimebound]])
     //   GSLPointer func(const Foo& foo [[clang::lifetimebound]])
     if (FD &&
-        ((FD->getReturnType()->isReferenceType() &&
+        ((FD->getReturnType()->isPointerOrReferenceType() &&
           isRecordWithAttr<OwnerAttr>(FD->getReturnType()->getPointeeType())) 
||
-         isPointerLikeType(FD->getReturnType())))
+          isGLSPointerType(FD->getReturnType())))
       return Report;
 
     return Abandon;
diff --git a/clang/test/Sema/Inputs/lifetime-analysis.h 
b/clang/test/Sema/Inputs/lifetime-analysis.h
index d318033ff0cc4..2072e4603cead 100644
--- a/clang/test/Sema/Inputs/lifetime-analysis.h
+++ b/clang/test/Sema/Inputs/lifetime-analysis.h
@@ -61,6 +61,7 @@ struct basic_string_view {
   basic_string_view();
   basic_string_view(const T *);
   const T *begin() const;
+  const T *data() const;
 };
 using string_view = basic_string_view<char>;
 
@@ -80,6 +81,7 @@ struct basic_string {
   const T *c_str() const;
   operator basic_string_view<T> () const;
   using const_iterator = iter<T>;
+  const T *data() const;
 };
 using string = basic_string<char>;
 
diff --git a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp 
b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
index 04bb1330ded4c..a65bb936ca8cb 100644
--- a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
+++ b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
@@ -852,3 +852,27 @@ struct Test {
 };
 
 } // namespace GH120543
+
+namespace GH127195 {
+template <typename T>
+struct StatusOr {
+  T* operator->() [[clang::lifetimebound]];
+  T* value() [[clang::lifetimebound]];
+};
+
+const char* foo() {
+  StatusOr<std::string> s;
+  return s->data(); // expected-warning {{address of stack memory associated 
with local variable}}
+  
+  StatusOr<std::string_view> s2;
+  return s2->data();
+
+  StatusOr<StatusOr<std::string_view>> s3;
+  return s3.value()->value()->data();
+
+  // would be nice to support the nested cases.
+  StatusOr<StatusOr<std::string>> s4;
+  return s4.value()->value()->data();
+}
+
+} // namespace GH127195

>From 29e49e18339c7c2f2e9694c37a859967922c89e8 Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein...@gmail.com>
Date: Mon, 17 Feb 2025 14:23:39 +0100
Subject: [PATCH 2/3] add FIXME

---
 clang/test/Sema/warn-lifetime-analysis-nocfg.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp 
b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
index a65bb936ca8cb..66a2a19ceb321 100644
--- a/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
+++ b/clang/test/Sema/warn-lifetime-analysis-nocfg.cpp
@@ -870,7 +870,7 @@ const char* foo() {
   StatusOr<StatusOr<std::string_view>> s3;
   return s3.value()->value()->data();
 
-  // would be nice to support the nested cases.
+  // FIXME: nested cases are not supported now.
   StatusOr<StatusOr<std::string>> s4;
   return s4.value()->value()->data();
 }

>From 3f102069a5af3bd777e827735ea46d158a042193 Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein...@gmail.com>
Date: Mon, 17 Feb 2025 14:27:57 +0100
Subject: [PATCH 3/3] clang-format

---
 clang/lib/Sema/CheckExprLifetime.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/lib/Sema/CheckExprLifetime.cpp 
b/clang/lib/Sema/CheckExprLifetime.cpp
index 3e0867343ccee..1f87001f35b57 100644
--- a/clang/lib/Sema/CheckExprLifetime.cpp
+++ b/clang/lib/Sema/CheckExprLifetime.cpp
@@ -1244,7 +1244,7 @@ static AnalysisResult analyzePathForGSLPointer(const 
IndirectLocalPath &Path,
     if (FD &&
         ((FD->getReturnType()->isPointerOrReferenceType() &&
           isRecordWithAttr<OwnerAttr>(FD->getReturnType()->getPointeeType())) 
||
-          isGLSPointerType(FD->getReturnType())))
+         isGLSPointerType(FD->getReturnType())))
       return Report;
 
     return Abandon;

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