https://github.com/royitaqi created
https://github.com/llvm/llvm-project/pull/156803
# Usage
```
--time-to-live <ttl> When using --connection, the number of milliseconds to
wait for new connections
at the beginning and after all clients have
disconnected. Not specifying this
argument or specifying non-positive values will wait
indefinitely.
```
# Benefits
Automatic release of resources when lldb-dap is no longer being used (e.g.
release memory used by module cache).
# Test
TBD. I will find a test file to add tests.
>From 9af1b0029e3e19b521d472d8c94596709f990166 Mon Sep 17 00:00:00 2001
From: Roy Shi <roy...@meta.com>
Date: Wed, 3 Sep 2025 22:23:20 -0700
Subject: [PATCH] [lldb-dap] Add optional TTL argument when using --connection
---
lldb/tools/lldb-dap/Options.td | 7 ++++
lldb/tools/lldb-dap/tool/lldb-dap.cpp | 53 ++++++++++++++++++++++++++-
2 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/lldb/tools/lldb-dap/Options.td b/lldb/tools/lldb-dap/Options.td
index 867753e9294a6..754b8c7d03568 100644
--- a/lldb/tools/lldb-dap/Options.td
+++ b/lldb/tools/lldb-dap/Options.td
@@ -61,3 +61,10 @@ def pre_init_command: S<"pre-init-command">,
def: Separate<["-"], "c">,
Alias<pre_init_command>,
HelpText<"Alias for --pre-init-command">;
+
+def time_to_live: S<"time-to-live">,
+ MetaVarName<"<ttl>">,
+ HelpText<"When using --connection, the number of milliseconds to wait "
+ "for new connections at the beginning and after all clients have "
+ "disconnected. Not specifying this argument or specifying "
+ "non-positive values will wait indefinitely.">;
diff --git a/lldb/tools/lldb-dap/tool/lldb-dap.cpp
b/lldb/tools/lldb-dap/tool/lldb-dap.cpp
index b74085f25f4e2..8b53e4d5cda83 100644
--- a/lldb/tools/lldb-dap/tool/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/tool/lldb-dap.cpp
@@ -258,7 +258,7 @@ validateConnection(llvm::StringRef conn) {
static llvm::Error
serveConnection(const Socket::SocketProtocol &protocol, const std::string
&name,
Log *log, const ReplMode default_repl_mode,
- const std::vector<std::string> &pre_init_commands) {
+ const std::vector<std::string> &pre_init_commands, int ttl) {
Status status;
static std::unique_ptr<Socket> listener = Socket::Create(protocol, status);
if (status.Fail()) {
@@ -283,6 +283,21 @@ serveConnection(const Socket::SocketProtocol &protocol,
const std::string &name,
g_loop.AddPendingCallback(
[](MainLoopBase &loop) { loop.RequestTermination(); });
});
+ static MainLoopBase::TimePoint ttl_time_point;
+ static std::mutex ttl_mutex;
+ if (ttl > 0) {
+ std::scoped_lock<std::mutex> lock(ttl_mutex);
+ MainLoopBase::TimePoint future =
+ std::chrono::steady_clock::now() + std::chrono::milliseconds(ttl);
+ ttl_time_point = future;
+ g_loop.AddCallback(
+ [future](MainLoopBase &loop) {
+ if (ttl_time_point == future) {
+ loop.RequestTermination();
+ }
+ },
+ future);
+ }
std::condition_variable dap_sessions_condition;
std::mutex dap_sessions_mutex;
std::map<MainLoop *, DAP *> dap_sessions;
@@ -291,6 +306,12 @@ serveConnection(const Socket::SocketProtocol &protocol,
const std::string &name,
&dap_sessions_mutex, &dap_sessions,
&clientCount](
std::unique_ptr<Socket> sock) {
+ if (ttl > 0) {
+ // Reset the keep alive timer, because we won't be killing the server
+ // while this connection is being served.
+ std::scoped_lock<std::mutex> lock(ttl_mutex);
+ ttl_time_point = MainLoopBase::TimePoint();
+ }
std::string client_name = llvm::formatv("client_{0}", clientCount++).str();
DAP_LOG(log, "({0}) client connected", client_name);
@@ -327,6 +348,23 @@ serveConnection(const Socket::SocketProtocol &protocol,
const std::string &name,
std::unique_lock<std::mutex> lock(dap_sessions_mutex);
dap_sessions.erase(&loop);
std::notify_all_at_thread_exit(dap_sessions_condition, std::move(lock));
+
+ if (ttl > 0) {
+ // Start the countdown to kill the server at the end of each
connection.
+ std::scoped_lock<std::mutex> lock(ttl_mutex);
+ MainLoopBase::TimePoint future =
+ std::chrono::steady_clock::now() + std::chrono::milliseconds(ttl);
+ // We don't need to take the max of `keep_alive_up_to` and `future`,
+ // because `future` must be the latest.
+ ttl_time_point = future;
+ g_loop.AddCallback(
+ [future](MainLoopBase &loop) {
+ if (ttl_time_point == future) {
+ loop.RequestTermination();
+ }
+ },
+ future);
+ }
});
client.detach();
});
@@ -509,6 +547,17 @@ int main(int argc, char *argv[]) {
}
if (!connection.empty()) {
+ int ttl = 0;
+ llvm::opt::Arg *time_to_live = input_args.getLastArg(OPT_time_to_live);
+ if (time_to_live) {
+ llvm::StringRef time_to_live_value = time_to_live->getValue();
+ if (time_to_live_value.getAsInteger(10, ttl)) {
+ llvm::errs() << "'" << time_to_live_value
+ << "' is not a valid time-to-live value\n";
+ return EXIT_FAILURE;
+ }
+ }
+
auto maybeProtoclAndName = validateConnection(connection);
if (auto Err = maybeProtoclAndName.takeError()) {
llvm::logAllUnhandledErrors(std::move(Err), llvm::errs(),
@@ -520,7 +569,7 @@ int main(int argc, char *argv[]) {
std::string name;
std::tie(protocol, name) = *maybeProtoclAndName;
if (auto Err = serveConnection(protocol, name, log.get(),
default_repl_mode,
- pre_init_commands)) {
+ pre_init_commands, ttl)) {
llvm::logAllUnhandledErrors(std::move(Err), llvm::errs(),
"Connection failed: ");
return EXIT_FAILURE;
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