[clang] [Sema] Fix assertion crash on section conflict with a non-identifier decl (PR #200873)

[via cfe-commits]

https://github.com/lijinpei-amd updated https://github.com/llvm/llvm-project/pull/200873

>From 38f79eb3acd6e16628459517ae285d177fed46f3 Mon Sep 17 00:00:00 2001
From: Li Jinpei <jinpli at amd.com>
Date: Tue, 2 Jun 2026 00:55:37 +0800
Subject: [PATCH 1/3] [Sema] Fix assertion crash on section conflict with a
 non-identifier decl

NamedDecl::getName() asserts the name is a simple identifier, so
UnifySection crashed when the conflicting section decl had a special
name such as a lambda's call operator.

Drop the argument: `note_declared_at` has no format placeholder,
so it was dead code. The error already prints the section decl.

Fixes https://github.com/llvm/llvm-project/issues/192264
---
 clang/lib/Sema/SemaAttr.cpp         |  6 ++----
 clang/test/SemaCXX/attr-section.cpp | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index ffd546138008a..67573c9f1c72a 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -853,8 +853,7 @@ bool Sema::UnifySection(StringRef SectionName, int SectionFlags,
     return false;
   Diag(Decl->getLocation(), diag::err_section_conflict) << Decl << Section;
   if (Section.Decl)
-    Diag(Section.Decl->getLocation(), diag::note_declared_at)
-        << Section.Decl->getName();
+    Diag(Section.Decl->getLocation(), diag::note_declared_at);
   if (PragmaLocation.isValid())
     Diag(PragmaLocation, diag::note_pragma_entered_here);
   if (Section.PragmaSectionLocation.isValid())
@@ -874,8 +873,7 @@ bool Sema::UnifySection(StringRef SectionName,
       Diag(PragmaSectionLocation, diag::err_section_conflict)
           << "this" << Section;
       if (Section.Decl)
-        Diag(Section.Decl->getLocation(), diag::note_declared_at)
-            << Section.Decl->getName();
+        Diag(Section.Decl->getLocation(), diag::note_declared_at);
       if (Section.PragmaSectionLocation.isValid())
         Diag(Section.PragmaSectionLocation, diag::note_pragma_entered_here);
       return true;
diff --git a/clang/test/SemaCXX/attr-section.cpp b/clang/test/SemaCXX/attr-section.cpp
index 1c07e3dd8bba2..35d38ec6e2be0 100644
--- a/clang/test/SemaCXX/attr-section.cpp
+++ b/clang/test/SemaCXX/attr-section.cpp
@@ -69,3 +69,18 @@ __attribute__((section("non_trivial_ctor"))) const t1 v1; // expected-note {{dec
 extern const t1 v2;
 __attribute__((section("non_trivial_ctor"))) const t1 v2{3}; // expected-error {{'v2' causes a section type conflict with 'v1'}}
 } // namespace non_trivial_ctor
+
+// Check that a section conflict with a decl whose name is not a simple
+// identifier (here, a lambda's call operator) is diagnosed without crashing.
+namespace lambda_call_operator {
+auto lambda = [](int val) __attribute__((section("lambda_op"))) { return val; }; // expected-note {{declared here}}
+__attribute__((section("lambda_op"))) int i{}; // expected-error {{'i' causes a section type conflict with 'operator()'}}
+} // namespace lambda_call_operator
+
+// Check that a section conflict with a decl whose name is not a simple
+// identifier (here, a lambda's call operator) is diagnosed without crashing.
+namespace lambda_call_operator_pragma {
+auto lambda = [](int val) __attribute__((section("lambda_op_pragma"))) { return val; }; // expected-note {{declared here}}
+#pragma clang section bss="lambda_op_pragma" // expected-error {{this causes a section type conflict with 'operator()'}}
+#pragma clang section bss=""
+} // namespace lambda_call_operator_pragma

>From c6a548b2a66b3d37ab8a2667451176f4718411a4 Mon Sep 17 00:00:00 2001
From: lijinpei-amd <jinpei.li at amd.com>
Date: Tue, 2 Jun 2026 16:58:04 +0800
Subject: [PATCH 2/3] Update clang/test/SemaCXX/attr-section.cpp

Co-authored-by: Corentin Jabot <corentinjabot at gmail.com>
---
 clang/test/SemaCXX/attr-section.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/test/SemaCXX/attr-section.cpp b/clang/test/SemaCXX/attr-section.cpp
index 35d38ec6e2be0..7252ef7694b27 100644
--- a/clang/test/SemaCXX/attr-section.cpp
+++ b/clang/test/SemaCXX/attr-section.cpp
@@ -72,7 +72,7 @@ __attribute__((section("non_trivial_ctor"))) const t1 v2{3}; // expected-error {
 
 // Check that a section conflict with a decl whose name is not a simple
 // identifier (here, a lambda's call operator) is diagnosed without crashing.
-namespace lambda_call_operator {
+namespace GH192264 {
 auto lambda = [](int val) __attribute__((section("lambda_op"))) { return val; }; // expected-note {{declared here}}
 __attribute__((section("lambda_op"))) int i{}; // expected-error {{'i' causes a section type conflict with 'operator()'}}
 } // namespace lambda_call_operator

>From efd9e1a237e5fc5375ff649661721da1738ed863 Mon Sep 17 00:00:00 2001
From: Li Jinpei <jinpli at amd.com>
Date: Tue, 2 Jun 2026 17:03:02 +0800
Subject: [PATCH 3/3] [Sema] Add release note for section-conflict crash fix

Address review: add a ReleaseNotes.rst entry referencing GH192264, and
fix a stale closing-namespace comment left by the GH192264 rename.
---
 clang/docs/ReleaseNotes.rst         | 3 +++
 clang/test/SemaCXX/attr-section.cpp | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index d1c58435ab399..c279e00758134 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -666,6 +666,9 @@ Bug Fixes to Attribute Support
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 - Fixed a behavioral discrepancy between deleted functions and private members when checking the ``enable_if`` attribute. (#GH175895)
 - Fixed ``init_priority`` attribute by delaying type checks until after the type is deduced.
+- Fixed a crash when a ``section`` attribute or ``#pragma clang section`` caused a
+  section type conflict with a declaration whose name is not a simple identifier,
+  such as a lambda's call operator. (#GH192264)
 
 Bug Fixes to C++ Support
 ^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/test/SemaCXX/attr-section.cpp b/clang/test/SemaCXX/attr-section.cpp
index 7252ef7694b27..95d4fc53ebe6c 100644
--- a/clang/test/SemaCXX/attr-section.cpp
+++ b/clang/test/SemaCXX/attr-section.cpp
@@ -75,7 +75,7 @@ __attribute__((section("non_trivial_ctor"))) const t1 v2{3}; // expected-error {
 namespace GH192264 {
 auto lambda = [](int val) __attribute__((section("lambda_op"))) { return val; }; // expected-note {{declared here}}
 __attribute__((section("lambda_op"))) int i{}; // expected-error {{'i' causes a section type conflict with 'operator()'}}
-} // namespace lambda_call_operator
+} // namespace GH192264
 
 // Check that a section conflict with a decl whose name is not a simple
 // identifier (here, a lambda's call operator) is diagnosed without crashing.