[Lldb-commits] [lldb] [lldb] Support building lldbHost under Emscripten (PR #223206)

[Anutosh Bhat via lldb-commits]

https://github.com/anutosh491 updated https://github.com/llvm/llvm-project/pull/223206

>From 85fb29805254a659245e909b8b488b5a06b4b963 Mon Sep 17 00:00:00 2001
From: anutosh491 <andersonbhat491 at gmail.com>
Date: Sun, 13 Sep 2026 10:42:26 +0530
Subject: [PATCH] [lldb] Support building lldbHost under Emscripten

---
 lldb/source/Host/CMakeLists.txt      |  8 +++++++-
 lldb/source/Host/common/Host.cpp     |  6 +++---
 lldb/source/Host/emscripten/Host.cpp | 29 ++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 4 deletions(-)
 create mode 100644 lldb/source/Host/emscripten/Host.cpp

diff --git a/lldb/source/Host/CMakeLists.txt b/lldb/source/Host/CMakeLists.txt
index ef99c79deab82..45821aa410912 100644
--- a/lldb/source/Host/CMakeLists.txt
+++ b/lldb/source/Host/CMakeLists.txt
@@ -111,10 +111,15 @@ else()
     posix/LockFilePosix.cpp
     posix/MainLoopPosix.cpp
     posix/PipePosix.cpp
-    posix/ProcessLauncherPosixFork.cpp
     posix/Support.cpp
     )
 
+  if (NOT EMSCRIPTEN)
+    add_host_subdirectory(posix
+      posix/ProcessLauncherPosixFork.cpp
+      )
+  endif()
+
   if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
     add_subdirectory(macosx/objcxx)
     set(LLDBObjCLibs lldbHostMacOSXObjCXX)
@@ -137,6 +142,7 @@ else()
     endif()
   elseif (CMAKE_SYSTEM_NAME MATCHES "Emscripten")
     add_host_subdirectory(emscripten
+      emscripten/Host.cpp
       emscripten/HostInfoEmscripten.cpp
       )
   elseif (CMAKE_SYSTEM_NAME MATCHES "Linux|Android")
diff --git a/lldb/source/Host/common/Host.cpp b/lldb/source/Host/common/Host.cpp
index c4e1500fe68ab..fdf17db53ec3e 100644
--- a/lldb/source/Host/common/Host.cpp
+++ b/lldb/source/Host/common/Host.cpp
@@ -67,7 +67,7 @@
 #if defined(_WIN32)
 #include "lldb/Host/windows/ConnectionGenericFileWindows.h"
 #include "lldb/Host/windows/ProcessLauncherWindows.h"
-#else
+#elif !defined(__EMSCRIPTEN__)
 #include "lldb/Host/posix/ProcessLauncherPosixFork.h"
 #endif
 
@@ -581,7 +581,7 @@ Status Host::RunShellCommand(llvm::StringRef shell_path, const Args &args,
 
 // The functions below implement process launching for non-Apple-based
 // platforms
-#if !defined(__APPLE__)
+#if !defined(__APPLE__) && !defined(__EMSCRIPTEN__)
 Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
   std::unique_ptr<ProcessLauncher> delegate_launcher;
 #if defined(_WIN32)
@@ -600,7 +600,7 @@ Status Host::LaunchProcess(ProcessLaunchInfo &launch_info) {
 
   return error;
 }
-#endif // !defined(__APPLE__)
+#endif // !defined(__APPLE__) && !defined(__EMSCRIPTEN__)
 
 #ifndef _WIN32
 void Host::Kill(lldb::pid_t pid, int signo) { ::kill(pid, signo); }
diff --git a/lldb/source/Host/emscripten/Host.cpp b/lldb/source/Host/emscripten/Host.cpp
new file mode 100644
index 0000000000000..005a2f83f4ec7
--- /dev/null
+++ b/lldb/source/Host/emscripten/Host.cpp
@@ -0,0 +1,29 @@
+//===-- Host.cpp ---------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/Host.h"
+#include "lldb/Utility/Status.h"
+
+using namespace lldb_private;
+
+uint32_t Host::FindProcessesImpl(const ProcessInstanceInfoMatch &,
+                                 ProcessInstanceInfoList &) {
+  return 0;
+}
+
+bool Host::GetProcessInfo(lldb::pid_t, ProcessInstanceInfo &) { return false; }
+
+Status Host::LaunchProcess(ProcessLaunchInfo &) {
+  return Status::FromErrorString(
+      "launching a host process is not supported under Emscripten");
+}
+
+Status Host::ShellExpandArguments(ProcessLaunchInfo &) {
+  return Status::FromErrorString(
+      "shell expansion is not supported under Emscripten");
+}