From eb3e935b9704c591be9a951df48c1bea0b428be1 Mon Sep 17 00:00:00 2001
From: Jonathan Chambers <joncham@gmail.com>
Date: Tue, 15 Dec 2020 13:49:41 -0500
Subject: [PATCH] Implement check for sufficient execution stack.

Enable across platforms and expose to embedding API.
---
 mono/metadata/icall.c   | 35 +----------------------------------
 mono/metadata/threads.c | 30 ++++++++++++++++++++++++++++++
 mono/metadata/threads.h |  2 ++
 3 files changed, 33 insertions(+), 34 deletions(-)

diff --git a/mono/metadata/icall.c b/mono/metadata/icall.c
index ffec0503c95..6dbd881b152 100644
--- a/mono/metadata/icall.c
+++ b/mono/metadata/icall.c
@@ -1017,40 +1017,7 @@ ves_icall_System_Runtime_CompilerServices_RuntimeHelpers_RunModuleConstructor (M
 ICALL_EXPORT MonoBoolean
 ves_icall_System_Runtime_CompilerServices_RuntimeHelpers_SufficientExecutionStack (void)
 {
-#if defined(TARGET_WIN32) || defined(HOST_WIN32)
-	// It does not work on win32
-#elif defined(TARGET_ANDROID) || defined(__linux__)
-	// No need for now
-#else
-	guint8 *stack_addr;
-	guint8 *current;
-	size_t stack_size;
-	int min_size;
-	MonoInternalThread *thread;
-
-	mono_thread_info_get_stack_bounds (&stack_addr, &stack_size);
-	/* if we have no info we are optimistic and assume there is enough room */
-	if (!stack_addr)
-		return TRUE;
-
-	thread = mono_thread_internal_current ();
-	// .net seems to check that at least 50% of stack is available
-	min_size = thread->stack_size / 2;
-
-	// TODO: It's not always set
-	if (!min_size)
-		return TRUE;
-
-	current = (guint8 *)&stack_addr;
-	if (current > stack_addr) {
-		if ((current - stack_addr) < min_size)
-			return FALSE;
-	} else {
-		if (current - (stack_addr - stack_size) < min_size)
-			return FALSE;
-	}
-#endif
-	return TRUE;
+	return mono_thread_has_sufficient_execution_stack ();
 }
 
 ICALL_EXPORT MonoObject *
diff --git a/mono/metadata/threads.c b/mono/metadata/threads.c
index 379c7a7c6bd..23b2835b27e 100644
--- a/mono/metadata/threads.c
+++ b/mono/metadata/threads.c
@@ -5678,3 +5678,33 @@ MonoException* mono_unity_thread_check_exception()
 	unlock_thread(thread);
 	return NULL;
 }
+
+mono_bool mono_thread_has_sufficient_execution_stack (void)
+{
+	guint8* stack_addr;
+	guint8* current;
+	size_t stack_size;
+	size_t min_size;
+
+	mono_thread_info_get_stack_bounds (&stack_addr, &stack_size);
+	/* if we have no info we are optimistic and assume there is enough room */
+	if (!stack_addr || !stack_size)
+		return TRUE;
+
+	min_size = stack_size / 2;
+
+	// TODO: It's not always set
+	if (!min_size)
+		return TRUE;
+
+	current = (guint8*)&stack_addr;
+	if (current > stack_addr) {
+		if ((current - stack_addr) < min_size)
+			return FALSE;
+	}
+	else {
+		if (current - (stack_addr - stack_size) < min_size)
+			return FALSE;
+	}
+	return TRUE;
+}
diff --git a/mono/metadata/threads.h b/mono/metadata/threads.h
index bad65287b58..b8cac2a1fd6 100644
--- a/mono/metadata/threads.h
+++ b/mono/metadata/threads.h
@@ -57,6 +57,8 @@ MONO_API mono_bool mono_thread_is_foreign (MonoThread *thread);
 
 extern MONO_API mono_bool mono_thread_detach_if_exiting (void);
 
+MONO_API mono_bool mono_thread_has_sufficient_execution_stack (void);
+
 MONO_END_DECLS
 
 #endif /* _MONO_METADATA_THREADS_H_ */
-- 
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