[lldb] Fix FindProcessImpl() for iOS simulators (llvm#139174)

royitaqi · web-flow · commit f63bc84b0d2a · 2025-06-25T16:38:29.000-07:00
# Benefit This patch fixes: 1. After `platform select ios-simulator`, `platform process list` will now print processes which are running in the iOS simulator. Previously, no process will be listed. 2. After `platform select ios-simulator`, `platform attach --name <name>` will succeed. Previously, it will error out saying no process is found. # Several bugs that is being fixed 1. During the process listing, add `aarch64` to the list of CPU types for which iOS simulators are checked for. 2. Given a candidate process, when checking for simulators, the original code will find the desired environment variable (`SIMULATOR_UDID`) and set the OS to iOS, but then the immediate next environment variable will set it back to macOS. 3. For processes running on simulator, set the triple's `Environment` to `Simulator`, so that such processes can pass the filtering [in this line](https://fburl.com/8nivnrjx). The original code leave it as the default `UnknownEnvironment`. # Manual test **With this patch:** ``` royshi-mac-home ~/public_llvm/build % bin/lldb (lldb) platform select ios-simulator (lldb) platform process list 240 matching processes were found on "ios-simulator" PID PARENT USER TRIPLE NAME ====== ====== ========== ============================== ============================ 40511 28844 royshi arm64-apple-ios-simulator FocusPlayground // my toy iOS app running on simulator ... // omit 28844 1 royshi arm64-apple-ios-simulator launchd_sim (lldb) process attach --name FocusPlayground Process 40511 stopped * thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP frame #0: 0x0000000104e3cb70 libsystem_kernel.dylib`mach_msg2_trap + 8 libsystem_kernel.dylib`mach_msg2_trap: -> 0x104e3cb70 <+8>: ret ... // omit ``` **Without this patch:** ``` $ bin/lldb (lldb) platform select ios-simulator (lldb) platform process list error: no processes were found on the "ios-simulator" platform (lldb) process attach --name FocusPlayground error: attach failed: could not find a process named FocusPlayground ``` # Unittest See PR.
diff --git a/lldb/packages/Python/lldbsuite/test/lldbutil.py b/lldb/packages/Python/lldbsuite/test/lldbutil.py
@@ -7,6 +7,7 @@
 # System modules
 import errno
 import io
+import json
 import os
 import re
 import sys
@@ -1704,3 +1705,89 @@ def packetlog_get_dylib_info(log):
                 expect_dylib_info_response = True
 
     return dylib_info
+
+
+# ========================
+# Utilities for simulators
+# ========================
+
+
+def get_latest_apple_simulator(platform_name, log=None):
+    # Run simctl to list all simulators
+    cmd = ["xcrun", "simctl", "list", "-j", "devices"]
+    cmd_str = " ".join(cmd)
+    if log:
+        log(cmd_str)
+    sim_devices_str = subprocess.check_output(cmd).decode("utf-8")
+    sim_devices = json.loads(sim_devices_str)["devices"]
+
+    # Find an available simulator for the requested platform
+    device_uuid = None
+    device_runtime = None
+    for simulator in sim_devices:
+        if isinstance(simulator, dict):
+            runtime = simulator["name"]
+            devices = simulator["devices"]
+        else:
+            runtime = simulator
+            devices = sim_devices[simulator]
+        if not platform_name in runtime.lower():
+            continue
+        for device in devices:
+            if "availability" in device and device["availability"] != "(available)":
+                continue
+            if "isAvailable" in device and not device["isAvailable"]:
+                continue
+            if device_runtime and runtime < device_runtime:
+                continue
+            device_uuid = device["udid"]
+            device_runtime = runtime
+            # Stop searching in this runtime
+            break
+
+    return device_uuid
+
+
+def launch_exe_in_apple_simulator(
+    device_uuid,
+    exe_path,
+    exe_args=[],
+    stderr_lines_to_read=0,
+    stderr_patterns=[],
+    log=None,
+):
+    exe_path = os.path.realpath(exe_path)
+    cmd = [
+        "xcrun",
+        "simctl",
+        "spawn",
+        "-s",
+        device_uuid,
+        exe_path,
+    ] + exe_args
+    if log:
+        log(" ".join(cmd))
+    sim_launcher = subprocess.Popen(cmd, stderr=subprocess.PIPE)
+
+    # Read stderr to try to find matches.
+    # Each pattern will return the value of group[1] of the first match in the stderr.
+    # Will read at most stderr_lines_to_read lines.
+    # Will early terminate when all matches have been found.
+    total_patterns = len(stderr_patterns)
+    matches_found = 0
+    matched_strings = [None] * total_patterns
+    for _ in range(0, stderr_lines_to_read):
+        stderr = sim_launcher.stderr.readline().decode("utf-8")
+        if not stderr:
+            continue
+        for i, pattern in enumerate(stderr_patterns):
+            if matched_strings[i] is not None:
+                continue
+            match = re.match(pattern, stderr)
+            if match:
+                matched_strings[i] = str(match.group(1))
+                matches_found += 1
+        if matches_found == total_patterns:
+            break
+
+    return exe_path, matched_strings
diff --git a/lldb/source/Host/macosx/objcxx/Host.mm b/lldb/source/Host/macosx/objcxx/Host.mm
@@ -595,7 +595,9 @@ DataExtractor data(arg_data.GetBytes(), arg_data_size,
       const llvm::Triple::ArchType triple_arch = triple.getArch();
       const bool check_for_ios_simulator =
           (triple_arch == llvm::Triple::x86 ||
-           triple_arch == llvm::Triple::x86_64);
+           triple_arch == llvm::Triple::x86_64 ||
+           triple_arch == llvm::Triple::aarch64);
+
       const char *cstr = data.GetCStr(&offset);
       if (cstr) {
         process_info.GetExecutableFile().SetFile(cstr, FileSpec::Style::native);
@@ -621,21 +623,20 @@ DataExtractor data(arg_data.GetBytes(), arg_data_size,
           }
 
           Environment &proc_env = process_info.GetEnvironment();
-          while ((cstr = data.GetCStr(&offset))) {
-            if (cstr[0] == '\0')
-              break;
-
-            if (check_for_ios_simulator) {
-              if (strncmp(cstr, "SIMULATOR_UDID=", strlen("SIMULATOR_UDID=")) ==
-                  0)
-                process_info.GetArchitecture().GetTriple().setOS(
-                    llvm::Triple::IOS);
-              else
-                process_info.GetArchitecture().GetTriple().setOS(
-                    llvm::Triple::MacOSX);
-            }
-
-            proc_env.insert(cstr);
+          bool is_simulator = false;
+          llvm::StringRef env_var;
+          while (!(env_var = data.GetCStr(&offset)).empty()) {
+            if (check_for_ios_simulator &&
+                env_var.starts_with("SIMULATOR_UDID="))
+              is_simulator = true;
+            proc_env.insert(env_var);
+          }
+          llvm::Triple &triple = process_info.GetArchitecture().GetTriple();
+          if (is_simulator) {
+            triple.setOS(llvm::Triple::IOS);
+            triple.setEnvironment(llvm::Triple::Simulator);
+          } else {
+            triple.setOS(llvm::Triple::MacOSX);
           }
           return true;
         }
@@ -741,8 +742,8 @@ static bool GetMacOSXProcessUserAndGroup(ProcessInstanceInfo &process_info) {
         !match_info.ProcessIDsMatch(process_info))
       continue;
 
-    // Get CPU type first so we can know to look for iOS simulator is we have
-    // x86 or x86_64
+    // Get CPU type first so we can know to look for iOS simulator if we have
+    // a compatible type.
     if (GetMacOSXProcessCPUType(process_info)) {
       if (GetMacOSXProcessArgs(&match_info, process_info)) {
         if (match_info.Matches(process_info))
diff --git a/lldb/test/API/macosx/simulator/Makefile b/lldb/test/API/macosx/simulator/Makefile
@@ -1,3 +1,6 @@
-C_SOURCES := hello.c
+CFLAGS_EXTRAS := -D__STDC_LIMIT_MACROS -D__STDC_FORMAT_MACROS
+ENABLE_THREADS := YES
+CXX_SOURCES := hello.cpp
+MAKE_DSYM := NO
 
 include Makefile.rules
diff --git a/lldb/test/API/macosx/simulator/TestSimulatorPlatform.py b/lldb/test/API/macosx/simulator/TestSimulatorPlatform.py
@@ -39,7 +39,9 @@ def check_debugserver(self, log, expected_platform, expected_version):
         if expected_version:
             self.assertEqual(aout_info["min_version_os_sdk"], expected_version)
 
-    def run_with(self, arch, os, vers, env, expected_load_command):
+    def run_with(
+        self, arch, os, vers, env, expected_load_command, expected_platform=None
+    ):
         env_list = [env] if env else []
         triple = "-".join([arch, "apple", os + vers] + env_list)
         sdk = lldbutil.get_xcode_sdk(os, env)
@@ -72,12 +74,47 @@ def run_with(self, arch, os, vers, env, expected_load_command):
         log = self.getBuildArtifact("packets.log")
         self.expect("log enable gdb-remote packets -f " + log)
         lldbutil.run_to_source_breakpoint(
-            self, "break here", lldb.SBFileSpec("hello.c")
+            self, "break here", lldb.SBFileSpec("hello.cpp")
         )
         triple_re = "-".join([arch, "apple", os + vers + ".*"] + env_list)
         self.expect("image list -b -t", patterns=[r"a\.out " + triple_re])
         self.check_debugserver(log, os + env, vers)
 
+        if expected_platform is not None:
+            # Verify the platform name.
+            self.expect(
+                "platform status",
+                patterns=[r"Platform: " + expected_platform + "-simulator"],
+            )
+
+            # Launch exe in simulator and verify that `platform process list` can find the process.
+            # This separate launch is needed because the command ignores processes which are being debugged.
+            device_udid = lldbutil.get_latest_apple_simulator(
+                expected_platform, self.trace
+            )
+            _, matched_strings = lldbutil.launch_exe_in_apple_simulator(
+                device_udid,
+                self.getBuildArtifact("a.out"),
+                exe_args=[],
+                stderr_lines_to_read=1,  # in hello.cpp, the pid is printed first
+                stderr_patterns=[r"PID: (.*)"],
+                log=self.trace,
+            )
+
+            # Make sure we found the PID.
+            self.assertIsNotNone(matched_strings[0])
+            pid = int(matched_strings[0])
+
+            # Verify that processes on the platform can be listed.
+            self.expect(
+                "platform process list",
+                patterns=[
+                    r"\d+ matching processes were found on \"%s-simulator\""
+                    % expected_platform,
+                    r"%d .+ a.out" % pid,
+                ],
+            )
+
     @skipIfAsan
     @skipUnlessDarwin
     @skipIfDarwinEmbedded
@@ -90,6 +127,7 @@ def test_ios(self):
             vers="",
             env="simulator",
             expected_load_command="LC_BUILD_VERSION",
+            expected_platform="ios",
         )
 
     @skipIfAsan
diff --git a/lldb/test/API/macosx/simulator/hello.c b/lldb/test/API/macosx/simulator/hello.c
diff --git a/lldb/test/API/macosx/simulator/hello.cpp b/lldb/test/API/macosx/simulator/hello.cpp
@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <thread>
+#include <unistd.h>
+
+static void print_pid() { fprintf(stderr, "PID: %d\n", getpid()); }
+
+static void sleep() { std::this_thread::sleep_for(std::chrono::seconds(10)); }
+
+int main(int argc, char **argv) {
+  print_pid();
+  puts("break here\n");
+  sleep();
+  return 0;
+}
diff --git a/lldb/test/API/tools/lldb-server/TestAppleSimulatorOSType.py b/lldb/test/API/tools/lldb-server/TestAppleSimulatorOSType.py
@@ -14,40 +14,12 @@ class TestAppleSimulatorOSType(gdbremote_testcase.GdbRemoteTestCaseBase):
     READ_LINES = 10
 
     def check_simulator_ostype(self, sdk, platform_name, arch=platform.machine()):
-        cmd = ["xcrun", "simctl", "list", "-j", "devices"]
-        cmd_str = " ".join(cmd)
-        self.trace(cmd_str)
-        sim_devices_str = subprocess.check_output(cmd).decode("utf-8")
+        # Get simulator
+        deviceUDID = None
         try:
-            sim_devices = json.loads(sim_devices_str)["devices"]
+            deviceUDID = lldbutil.get_latest_apple_simulator(platform_name, self.trace)
         except json.decoder.JSONDecodeError:
-            self.fail(
-                "Could not parse '{}' output. Authorization denied?".format(cmd_str)
-            )
-        # Find an available simulator for the requested platform
-        deviceUDID = None
-        deviceRuntime = None
-        for simulator in sim_devices:
-            if isinstance(simulator, dict):
-                runtime = simulator["name"]
-                devices = simulator["devices"]
-            else:
-                runtime = simulator
-                devices = sim_devices[simulator]
-            if not platform_name in runtime.lower():
-                continue
-            for device in devices:
-                if "availability" in device and device["availability"] != "(available)":
-                    continue
-                if "isAvailable" in device and not device["isAvailable"]:
-                    continue
-                if deviceRuntime and runtime < deviceRuntime:
-                    continue
-                deviceUDID = device["udid"]
-                deviceRuntime = runtime
-                # Stop searching in this runtime
-                break
-
+            self.fail("Could not parse output. Authorization denied?")
         if not deviceUDID:
             self.skipTest(
                 "Could not find a simulator for {} ({})".format(platform_name, arch)
@@ -78,34 +50,20 @@ def check_simulator_ostype(self, sdk, platform_name, arch=platform.machine()):
             },
             compiler=clang,
         )
-        exe_path = os.path.realpath(self.getBuildArtifact(exe_name))
-        cmd = [
-            "xcrun",
-            "simctl",
-            "spawn",
-            "-s",
+
+        # Launch the executable in the simulator
+        exe_path, matched_groups = lldbutil.launch_exe_in_apple_simulator(
             deviceUDID,
-            exe_path,
-            "print-pid",
-            "sleep:10",
-        ]
-        self.trace(" ".join(cmd))
-        sim_launcher = subprocess.Popen(cmd, stderr=subprocess.PIPE)
-        # Get the PID from the process output
-        pid = None
-
-        # Read the first READ_LINES to try to find the PID.
-        for _ in range(0, self.READ_LINES):
-            stderr = sim_launcher.stderr.readline().decode("utf-8")
-            if not stderr:
-                continue
-            match = re.match(r"PID: (.*)", stderr)
-            if match:
-                pid = int(match.group(1))
-                break
+            self.getBuildArtifact(exe_name),
+            ["print-pid", "sleep:10"],
+            self.READ_LINES,
+            [r"PID: (.*)"],
+            self.trace,
+        )
 
         # Make sure we found the PID.
-        self.assertIsNotNone(pid)
+        self.assertIsNotNone(matched_groups[0])
+        pid = int(matched_groups[0])
 
         # Launch debug monitor attaching to the simulated process
         server = self.connect_to_debug_monitor(attach_pid=pid)
