From 8bec57a00d3a20598746971dab9f81031f009a97 Mon Sep 17 00:00:00 2001
From: Vladimir Shiryaev <tagolog@users.noreply.github.com>
Date: Thu, 24 Sep 2026 17:43:40 -0700
Subject: [PATCH 1/2] [llvm][Support] Use ::closesocket for native sockets on
 Windows

Calling ::close on a Windows SOCKET that has not been converted with _open_osfhandle crashes and aborts the process instead of returning an error.

Use ::closesocket on Windows for those sockets, and keep ::close on POSIX.
---
 llvm/lib/Support/raw_socket_stream.cpp        | 33 +++++++++++++++----
 .../Support/raw_socket_stream_test.cpp        | 10 ++++++
 2 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Support/raw_socket_stream.cpp b/llvm/lib/Support/raw_socket_stream.cpp
index cdf793c8958f9..6e78a17a968e3 100644
--- a/llvm/lib/Support/raw_socket_stream.cpp
+++ b/llvm/lib/Support/raw_socket_stream.cpp
@@ -61,6 +61,20 @@ static std::error_code getLastSocketErrorCode() {
 #endif
 }
 
+#ifdef _WIN32
+using NativeSocket = SOCKET;
+#else
+using NativeSocket = int;
+#endif
+
+static int closeSocket(NativeSocket Socket) {
+#ifdef _WIN32
+  return ::closesocket(Socket);
+#else
+  return ::close(Socket);
+#endif
+}
+
 static Expected<sockaddr_un> setSocketAddr(StringRef SocketPath) {
   struct sockaddr_un Addr;
   memset(&Addr, 0, sizeof(Addr));
@@ -97,13 +111,16 @@ static Expected<int> getSocketFD(StringRef SocketPath) {
   setsockopt(Socket, SOL_SOCKET, SO_PEERCRED, NULL, 0);
 #endif
   Expected<struct sockaddr_un> Addr = setSocketAddr(SocketPath);
-  if (!Addr)
+  if (!Addr) {
+    closeSocket(Socket);
     return Addr.takeError();
+  }
 
   if (::connect(Socket, (struct sockaddr *)&*Addr, sizeof(*Addr)) == -1) {
-    ::close(Socket);
-    return llvm::make_error<StringError>(getLastSocketErrorCode(),
-                                         "Connect socket failed");
+    // Grab the error code before closing, which may overwrite it.
+    std::error_code EC = getLastSocketErrorCode();
+    closeSocket(Socket);
+    return llvm::make_error<StringError>(EC, "Connect socket failed");
   }
 
 #ifdef _WIN32
@@ -177,13 +194,15 @@ Expected<ListeningSocket> ListeningSocket::createUnix(StringRef SocketPath,
   setsockopt(Socket, SOL_SOCKET, SO_PEERCRED, NULL, 0);
 #endif
   Expected<struct sockaddr_un> Addr = setSocketAddr(SocketPath);
-  if (!Addr)
+  if (!Addr) {
+    closeSocket(Socket);
     return Addr.takeError();
+  }
 
   if (::bind(Socket, (struct sockaddr *)&*Addr, sizeof(*Addr)) == -1) {
-    // Grab error code from call to ::bind before calling ::close
+    // Grab error code from call to ::bind before closing the socket
     std::error_code EC = getLastSocketErrorCode();
-    ::close(Socket);
+    closeSocket(Socket);
     return llvm::make_error<StringError>(EC, "Bind error");
   }
 
diff --git a/llvm/unittests/Support/raw_socket_stream_test.cpp b/llvm/unittests/Support/raw_socket_stream_test.cpp
index 293be53a25d21..673ef4f6b3e9f 100644
--- a/llvm/unittests/Support/raw_socket_stream_test.cpp
+++ b/llvm/unittests/Support/raw_socket_stream_test.cpp
@@ -99,6 +99,16 @@ TEST_F(raw_socket_streamTest, ACCEPT_WITH_TIMEOUT) {
             std::errc::timed_out);
 }
 
+TEST_F(raw_socket_streamTest, CONNECT_FAILURE_RETURNS_ERROR) {
+  ServerListener->shutdown();
+
+  // Connecting to a closed or nonexistent socket should return an error,
+  // not terminate the process while cleaning up the temporary native socket.
+  Expected<std::unique_ptr<raw_socket_stream>> MaybeClient =
+      raw_socket_stream::createConnectedUnix(SocketPath);
+  ASSERT_THAT_EXPECTED(MaybeClient, llvm::Failed());
+}
+
 TEST_F(raw_socket_streamTest, ACCEPT_WITH_SHUTDOWN) {
   // Create a separate thread to close the socket after a delay. Simulates a
   // signal handler calling ServerListener::shutdown

From d2bb12ed27f4e0c92eaa00da776b17a71490bad4 Mon Sep 17 00:00:00 2001
From: Vladimir Shiryaev <tagolog@users.noreply.github.com>
Date: Fri, 25 Sep 2026 10:13:51 -0700
Subject: [PATCH 2/2] [llvm][Support] Unify NativeSocket creation around
 INVALID_SOCKET so socket creation and the failure check are no longer
 duplicated

---
 llvm/lib/Support/raw_socket_stream.cpp | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/llvm/lib/Support/raw_socket_stream.cpp b/llvm/lib/Support/raw_socket_stream.cpp
index 6e78a17a968e3..d708b35673c7c 100644
--- a/llvm/lib/Support/raw_socket_stream.cpp
+++ b/llvm/lib/Support/raw_socket_stream.cpp
@@ -65,6 +65,7 @@ static std::error_code getLastSocketErrorCode() {
 using NativeSocket = SOCKET;
 #else
 using NativeSocket = int;
+#define INVALID_SOCKET -1
 #endif
 
 static int closeSocket(NativeSocket Socket) {
@@ -90,13 +91,8 @@ static Expected<sockaddr_un> setSocketAddr(StringRef SocketPath) {
 }
 
 static Expected<int> getSocketFD(StringRef SocketPath) {
-#ifdef _WIN32
-  SOCKET Socket = socket(AF_UNIX, SOCK_STREAM, 0);
+  NativeSocket Socket = socket(AF_UNIX, SOCK_STREAM, 0);
   if (Socket == INVALID_SOCKET) {
-#else
-  int Socket = socket(AF_UNIX, SOCK_STREAM, 0);
-  if (Socket == -1) {
-#endif // _WIN32
     return llvm::make_error<StringError>(getLastSocketErrorCode(),
                                          "Create socket failed");
   }
@@ -175,12 +171,9 @@ Expected<ListeningSocket> ListeningSocket::createUnix(StringRef SocketPath,
 
 #ifdef _WIN32
   WSABalancer _;
-  SOCKET Socket = socket(AF_UNIX, SOCK_STREAM, 0);
+#endif // _WIN32
+  NativeSocket Socket = socket(AF_UNIX, SOCK_STREAM, 0);
   if (Socket == INVALID_SOCKET)
-#else
-  int Socket = socket(AF_UNIX, SOCK_STREAM, 0);
-  if (Socket == -1)
-#endif
     return llvm::make_error<StringError>(getLastSocketErrorCode(),
                                          "socket create failed");