From 492e38069c9ca4eb6132fac300532840e4880a02 Mon Sep 17 00:00:00 2001
From: Nikolay Nikolov <nickysn@gmail.com>
Date: Fri, 23 Aug 2024 12:07:21 +0300
Subject: [PATCH] + WebAssembly threads: introduced
 TWasmThread.ThreadHasFinished boolean

---
 rtl/wasi/systhrd.inc | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/rtl/wasi/systhrd.inc b/rtl/wasi/systhrd.inc
index 1ae66a75f5..ae7800b1c6 100644
--- a/rtl/wasi/systhrd.inc
+++ b/rtl/wasi/systhrd.inc
@@ -50,6 +50,7 @@ Type
   TWasmThread = Record
     InitialStackPointer : Pointer;
     InitTLSBase : Pointer;
+    ThreadHasFinished : Boolean;
     ID : LongInt; // Allocated by host
     ThreadFunction : TThreadFunc;
     ThreadFunctionArg : Pointer;
@@ -446,6 +447,16 @@ asm
   local.get 0  ;; tid
   local.get 1  ;; start_arg
   call $FPCWasmThreadStartPascal
+
+  ;; Set start_arg^.ThreadHasFinished to true.
+  ;; This is done from within inline asm, after the pascal code has finished
+  ;; executing, because it indicates that the thread no longer needs its TLS
+  ;; block and linear stack block, so this means it's safe to free them.
+  local.get 1  ;; start_arg
+  i32.const 8  ;; offset to ThreadHasFinished
+  i32.add
+  i32.const 1  ;; true
+  i32.atomic.store8
 end;
 
 exports wasi_thread_start;