From 16010570bbbc8d3f7560415ef0d994e6b716b5e7 Mon Sep 17 00:00:00 2001
From: ondrej <ondrej@idefix.freepascal.org>
Date: Wed, 4 Nov 2020 14:55:40 +0000
Subject: [PATCH] * lazy thread initialization support

git-svn-id: trunk@47308 -
(cherry picked from commit c64429cdd0465c60e775c77c41afa464ab0a527f)
---
 rtl/beos/bethreads.pp    |  2 ++
 rtl/inc/thread.inc       | 28 ++++++++++++++++++++++++++++
 rtl/inc/threadh.inc      |  4 ++++
 rtl/netware/systhrd.inc  |  2 ++
 rtl/netwlibc/systhrd.inc |  2 ++
 rtl/unix/cthreads.pp     |  7 ++++++-
 rtl/win/systhrd.inc      |  7 ++++++-
 7 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/rtl/beos/bethreads.pp b/rtl/beos/bethreads.pp
index fe437f0474..ee2c47c6e5 100644
--- a/rtl/beos/bethreads.pp
+++ b/rtl/beos/bethreads.pp
@@ -168,6 +168,8 @@ Uses
            pthread_key_create(@TLSKey,nil);
            InitThreadVars(@CRelocateThreadvar);
 {$endif HASTHREADVAR}
+          { lazy initialize thread support }
+           LazyInitThreading;
            IsMultiThread:=true;
          end;
         { the only way to pass data to the newly created thread
diff --git a/rtl/inc/thread.inc b/rtl/inc/thread.inc
index 94f8a602ef..8dec424044 100644
--- a/rtl/inc/thread.inc
+++ b/rtl/inc/thread.inc
@@ -342,6 +342,34 @@ begin
   currenttm.RTLEventWaitForTimeout(state,timeout);
 end;
 
+{ ---------------------------------------------------------------------
+    lazy thread initialization support
+  ---------------------------------------------------------------------}
+
+var
+  LazyInitThreadingProcs : array of TProcedure = nil;
+procedure RegisterLazyInitThreadingProc(const proc: TProcedure);
+begin
+  if IsMultiThread then
+    begin
+    { multithreading is already enabled - execute directly }
+    proc();
+    end
+  else
+    begin
+    SetLength(LazyInitThreadingProcs,Length(LazyInitThreadingProcs)+1);
+    LazyInitThreadingProcs[high(LazyInitThreadingProcs)]:=proc;
+    end;
+end;
+
+procedure LazyInitThreading;
+var
+  i: Integer;
+begin
+  for i:=0 to high(LazyInitThreadingProcs) do
+    LazyInitThreadingProcs[i]();
+end;
+
 { ---------------------------------------------------------------------
     ThreadManager which gives run-time error. Use if no thread support.
   ---------------------------------------------------------------------}
diff --git a/rtl/inc/threadh.inc b/rtl/inc/threadh.inc
index 0d0b626f28..4f23d029e8 100644
--- a/rtl/inc/threadh.inc
+++ b/rtl/inc/threadh.inc
@@ -182,3 +182,7 @@ procedure RTLEventResetEvent(state:pRTLEvent);
 procedure RTLEventWaitFor(state:pRTLEvent);
 procedure RTLEventWaitFor(state:pRTLEvent;timeout : longint);
 
+{ lazy thread initialization support }
+procedure RegisterLazyInitThreadingProc(const proc: TProcedure);
+{ do not call LazyInitThreading directly}
+procedure LazyInitThreading;
diff --git a/rtl/netware/systhrd.inc b/rtl/netware/systhrd.inc
index c362c59704..298fc0a9ff 100644
--- a/rtl/netware/systhrd.inc
+++ b/rtl/netware/systhrd.inc
@@ -156,6 +156,8 @@ function SysBeginThread(sa : Pointer;stacksize : SizeUInt;
      if not IsMultiThread then
      begin
        InitThreadVars(@SysRelocateThreadvar);
+      { lazy initialize thread support }
+       LazyInitThreading;
        IsMultithread:=true;
      end;
      { the only way to pass data to the newly created thread }
diff --git a/rtl/netwlibc/systhrd.inc b/rtl/netwlibc/systhrd.inc
index 5d12022fad..6a3b5232b0 100644
--- a/rtl/netwlibc/systhrd.inc
+++ b/rtl/netwlibc/systhrd.inc
@@ -133,6 +133,8 @@
           { We're still running in single thread mode, setup the TLS }
            pthread_key_create(@TLSKey,nil);
            InitThreadVars(@SysRelocateThreadvar);
+          { lazy initialize thread support }
+           LazyInitThreading;
            IsMultiThread:=true;
          end;
         { the only way to pass data to the newly created thread
diff --git a/rtl/unix/cthreads.pp b/rtl/unix/cthreads.pp
index 76bd636f52..2ee2d5a484 100644
--- a/rtl/unix/cthreads.pp
+++ b/rtl/unix/cthreads.pp
@@ -351,7 +351,12 @@ Type  PINTRTLEvent = ^TINTRTLEvent;
       { Initialize multithreading if not done }
       if not TLSInitialized then
         InitCTLS;
-      IsMultiThread:=true;
+      if not IsMultiThread then
+        begin
+          { We're still running in single thread mode, lazy initialize thread support }
+           LazyInitThreading;
+           IsMultiThread:=true;
+        end;
 
       { the only way to pass data to the newly created thread
         in a MT safe way, is to use the heap }
diff --git a/rtl/win/systhrd.inc b/rtl/win/systhrd.inc
index 10bb07fda4..1d366ece51 100644
--- a/rtl/win/systhrd.inc
+++ b/rtl/win/systhrd.inc
@@ -256,7 +256,12 @@ var
 {$endif DEBUG_MT}
         { Initialize multithreading if not done }
         SysInitTLS;
-        IsMultiThread:=true;
+        if not IsMultiThread then
+          begin
+           { lazy initialize thread support }
+            LazyInitThreading;
+            IsMultiThread:=true;
+          end;
 
         { the only way to pass data to the newly created thread
           in a MT safe way, is to use the heap }