Fix [44b34c6152]: Fix crash on exit due to faulty asm code in DllMain

Author: jan.nijtmans

changes

@@ -8325,4 +8325,6 @@ Tk Cocoa 2.0: More drawing internals refinements (culler,walzer)
 
 2025-11-04 (bug) [6da885]: Aqua: avoid use-after-free during RefocusGrabWindow() (chavez)
 
+2025-11-11 (bug) [[44b34]: Fix crash on exit due to faulty asm code in DllMain (fuentes)
+
 - (to be) Released 8.6.18, Apr ??, 2026 - https://core.tcl-lang.org/tk/ for details

win/tkWin32Dll.c

@@ -104,6 +104,7 @@ DllMain(
 #if defined(HAVE_NO_SEH) && !defined(__aarch64__)
     TCLEXCEPTION_REGISTRATION registration;
 #endif
+    (void)reserved;
 
     /*
      * If we are attaching to the DLL from a new process, tell Tk about the
@@ -148,13 +149,21 @@ DllMain(
 
 	    "movq	%%rdx,		%%gs:0"		"\n\t"
 
-	    /*
-	     * Call TkFinalize
-	     */
+	    :
+	    /* No outputs */
+	    :
+	    [registration]	"m"	(registration),
+	    [error]		"i"	(TCL_ERROR)
+	    :
+	    "%rax", "%rdx", "memory"
+	);
 
-	    "movq	$0x0,		0x0(%%rsp)"		"\n\t"
-	    "call	TkFinalize"			"\n\t"
+        /* Just do a regular C call so we don't need to worry about following
+         * the calling convention, specially the registers the function may
+         * clobber: */
+        TkFinalize(NULL);
 
+	__asm__ __volatile__ (
 	    /*
 	     * Come here on a normal exit. Recover the TCLEXCEPTION_REGISTRATION
 	     * and store a TCL_OK status
@@ -188,11 +197,9 @@ DllMain(
 	    :
 	    /* No outputs */
 	    :
-	    [registration]	"m"	(registration),
-	    [ok]		"i"	(TCL_OK),
-	    [error]		"i"	(TCL_ERROR)
+	    [ok]		"i"	(TCL_OK)
 	    :
-	    "%rax", "%rbx", "%rcx", "%rdx", "%rsi", "%rdi", "memory"
+	    "%rax", "%rdx", "%rbp", "memory"
 	);
 
 #   else
@@ -218,12 +225,18 @@ DllMain(
 
 	    "movl	%%edx,		%%fs:0"		"\n\t"
 
-	    /*
-	     * Call TkFinalize
-	     */
+	    :
+	    /* No outputs */
+	    :
+	    [registration]	"m"	(registration),
+	    [error]		"i"	(TCL_ERROR)
+	    :
+	    "%eax", "%ebx", "%edx", "memory"
+	);
+
+        TkFinalize(NULL);
 
-	    "movl	$0x0,		0x0(%%esp)"		"\n\t"
-	    "call	_TkFinalize"			"\n\t"
+	__asm__ __volatile__ (
 
 	    /*
 	     * Come here on a normal exit. Recover the TCLEXCEPTION_REGISTRATION
@@ -259,11 +272,9 @@ DllMain(
 	    :
 	    /* No outputs */
 	    :
-	    [registration]	"m"	(registration),
-	    [ok]		"i"	(TCL_OK),
-	    [error]		"i"	(TCL_ERROR)
+	    [ok]		"i"	(TCL_OK)
 	    :
-	    "%eax", "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory"
+	    "%eax", "%ebx", "%edx", "%ebp", "memory"
 	);
 
 #   endif