[clang] [Clang] skip warnings for constructors marked with the [[noreturn]] attribute (PR #115558)

[Oleksandr T. via cfe-commits]

https://github.com/a-tarasyuk created 
https://github.com/llvm/llvm-project/pull/115558

Fixes #63009

>From f63263a1aa4873a63918649ea92352eb5cfe66eb Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.taras...@outlook.com>
Date: Sat, 9 Nov 2024 00:41:13 +0200
Subject: [PATCH] [Clang] skip warnings for constructors marked with the
 [[noreturn]] attribute

---
 clang/docs/ReleaseNotes.rst                       |  2 ++
 clang/lib/Analysis/CFG.cpp                        | 15 ++++++++++-----
 .../CXX/dcl.dcl/dcl.attr/dcl.attr.noreturn/p1.cpp | 12 ++++++++++++
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c3424e0e6f34c9..11d0e35d12a786 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -527,6 +527,8 @@ Improvements to Clang's diagnostics
 
 - Clang now diagnoses ``[[deprecated]]`` attribute usage on local variables 
(#GH90073).
 
+- Clang now omits warnings for constructors marked with the ``[[noreturn]]`` 
attribute (#GH63009).
+
 Improvements to Clang's time-trace
 ----------------------------------
 
diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index f678ac6f2ff36a..4d83f04c23060a 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -4889,16 +4889,21 @@ CFGBlock 
*CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
   return Visit(E->getSubExpr(), asc);
 }
 
-CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
+CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *E,
                                                   AddStmtChoice asc) {
   // If the constructor takes objects as arguments by value, we need to 
properly
   // construct these objects. Construction contexts we find here aren't for the
   // constructor C, they're for its arguments only.
-  findConstructionContextsForArguments(C);
+  findConstructionContextsForArguments(E);
 
-  autoCreateBlock();
-  appendConstructor(Block, C);
-  return VisitChildren(C);
+  CXXConstructorDecl *C = E->getConstructor();
+  if (C && C->isNoReturn())
+    Block = createNoReturnBlock();
+  else
+    autoCreateBlock();
+
+  appendConstructor(Block, E);
+  return VisitChildren(E);
 }
 
 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.noreturn/p1.cpp 
b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.noreturn/p1.cpp
index 56920ea8e8cf20..a96224dd03e360 100644
--- a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.noreturn/p1.cpp
+++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.noreturn/p1.cpp
@@ -49,3 +49,15 @@ void check() {
   test_type(g);
   test_type(h); // expected-note {{instantiation}}
 }
+
+namespace GH63009 {
+struct S {
+  [[noreturn]] S() { throw int {}; }
+};
+
+int test_no_return_constructor() { S(); } // ok
+
+int main() {
+  test_no_return_constructor();
+}
+}

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