rt: Make __morestack work on win32

src/rt/arch/i386/morestack.S

@@ -21,7 +21,7 @@
 #define UPCALL_DEL_STACK        _upcall_del_stack
 #define RUST_GET_TASK           _rust_get_task
 #define UPCALL_CALL_C           _upcall_call_shim_on_c_stack
-#define MORESTACK               __morestack
+#define MORESTACK               ___morestack
 #endif
 #endif
 
@@ -44,7 +44,6 @@
 	.type MORESTACK,@function
 #endif
 
-#if defined(__linux__) || defined(__APPLE__)
 MORESTACK:
 #ifdef __linux__
 	.cfi_startproc
@@ -144,11 +143,6 @@ MORESTACK:
 	.cfi_endproc
 #endif
 
-#else
-MORESTACK:
-	ret
-#endif
-
 #ifdef __APPLE__
 
 	.section __IMPORT,__pointers,non_lazy_symbol_pointers

src/rt/arch/i386/record_sp.S

@@ -16,17 +16,21 @@ RECORD_SP:
 	movl 4(%esp), %eax
 	movl %eax, %gs:48
 	ret
-#else
+#endif
+
 #if defined(__APPLE__)
 RECORD_SP:
 	movl $0x48+90*4, %eax
 	movl 4(%esp), %ecx
 	movl %ecx, %gs:(%eax)
 	ret
-#else
-RECORD_SP:
-	ret
 #endif
+
+#if defined(_WIN32)
+RECORD_SP:
+	movl 4(%esp), %eax
+	movl %eax, %fs:0x14
+	ret
 #endif
 
 GET_SP:

src/rt/rust_scheduler.cpp

@@ -394,6 +394,7 @@ void
 rust_scheduler::place_task_in_tls(rust_task *task) {
     BOOL result = TlsSetValue(task_key, task);
     assert(result && "Couldn't place the task in TLS!");
+    task->record_stack_limit();
 }
 
 rust_task *