From 5a722b0efa8afb173b3c16d46b826baf556ae8c5 Mon Sep 17 00:00:00 2001
From: Jake Turner <jake@evansturner.co.uk>
Date: Wed, 18 May 2022 08:18:19 +0100
Subject: [PATCH] Apple: cache debugger detection

Also added check if sysctl succeeded
---
 renderdoc/os/posix/apple/apple_process.cpp | 40 ++++++++++++++++------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/renderdoc/os/posix/apple/apple_process.cpp b/renderdoc/os/posix/apple/apple_process.cpp
index be5dd5c01..438b1f9d1 100644
--- a/renderdoc/os/posix/apple/apple_process.cpp
+++ b/renderdoc/os/posix/apple/apple_process.cpp
@@ -163,26 +163,44 @@ void ResumeProcess(pid_t childPid, uint32_t delay)
 {
 }
 
-void CacheDebuggerPresent()
-{
-}
+// Apple requires that this only be called in debug builds
+#define DEBUGGER_DETECTION (DISABLED(RDOC_RELEASE))
+
+// OSUtility::DebuggerPresent is called a lot
+// cache the value at startup as an optimisation
+#if DEBUGGER_DETECTION
+static bool s_debuggerPresent = false;
+static bool s_debuggerCached = false;
+#endif
 
 // from https://developer.apple.com/library/mac/qa/qa1361/_index.html on how to detect the debugger
-bool OSUtility::DebuggerPresent()
+void CacheDebuggerPresent()
 {
-// apple requires that this only be called in debug builds
-#if ENABLED(RDOC_RELEASE)
-  return false;
-#else
+#if DEBUGGER_DETECTION
   int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, getpid()};
   kinfo_proc info = {};
   size_t size = sizeof(info);
-  sysctl(mib, ARRAY_COUNT(mib), &info, &size, NULL, 0);
-
-  return info.kp_proc.p_flag & P_TRACED;
+  if(!sysctl(mib, ARRAY_COUNT(mib), &info, &size, NULL, 0))
+  {
+    s_debuggerPresent = (info.kp_proc.p_flag & P_TRACED);
+    s_debuggerCached = true;
+  }
 #endif
 }
 
+bool OSUtility::DebuggerPresent()
+{
+#if DEBUGGER_DETECTION
+  if(!s_debuggerCached)
+    CacheDebuggerPresent();
+  return s_debuggerPresent;
+#else
+  return false;
+#endif
+}
+
+#undef DEBUGGER_DETECTION
+
 rdcstr Process::GetEnvVariable(const rdcstr &name)
 {
   const char *val = getenv(name.c_str());