From acc877b3a7ec0e409247e8d8a39872285ec46469 Mon Sep 17 00:00:00 2001
From: Feoramund <161657516+Feoramund@users.noreply.github.com>
Date: Fri, 9 May 2025 17:34:33 -0400
Subject: [PATCH] Don't free virtual memory when ThreadSanitizer is active

This is a workaround for a lack of an ability to tell TSan that it
should clear any state it has about certain memory ranges to prevent
false positives.
---
 base/runtime/virtual_memory.odin | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/base/runtime/virtual_memory.odin b/base/runtime/virtual_memory.odin
index e8f676350..e4116d260 100644
--- a/base/runtime/virtual_memory.odin
+++ b/base/runtime/virtual_memory.odin
@@ -65,7 +65,19 @@ allocate_virtual_memory_aligned :: proc "contextless" (size: int, alignment: int
 Free virtual memory allocated by any of the `allocate_*` procs.
 */
 free_virtual_memory :: proc "contextless" (ptr: rawptr, size: int) {
-	_free_virtual_memory(ptr, size)
+	// TODO: There is currently no good way to tell ThreadSanitizer that we're
+	// done with a region of memory and to clear any information it has about
+	// it, so that when it's enabled, we simply do not release any memory back
+	// to the operating system.
+	//
+	// This prevents all false positive warnings when one thread inevitably
+	// gives up some of its memory that is then re-assigned to a different
+	// thread by the operating system.
+	//
+	// This is a workaround for the time being.
+	when .Thread not_in ODIN_SANITIZER_FLAGS {
+		_free_virtual_memory(ptr, size)
+	}
 }
 
 /*