Merge pull request #263 from Vogtinator/newliboptimization

Some newlib-related optimizations

Author: Vogtinator

ndless-sdk/libsyscalls/stdlib.cpp

@@ -8,6 +8,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/times.h>
+#include <sys/reent.h>
 #include <limits.h>
 #include <nucleus.h>
 #include <libndls.h>
@@ -24,6 +25,10 @@ extern int errno;
 #include <syscall-list.h>
 #include "syscall.h"
 
+namespace __gnu_cxx {
+	extern __attribute__((weak)) void __freeres();
+}
+
 extern "C" {
 
 // The only macro, I swear
@@ -197,6 +202,17 @@ void _exit(int ret)
 		nio_free(&csl);
 	#endif
 
+	// Free memory allocated by libstdc++
+	if(__gnu_cxx::__freeres)
+		__gnu_cxx::__freeres();
+
+	// Newlib doesn't reclaim data from the statically allocated reent
+	// itself, so do it here. It needs a bit of "convincing".
+	// See https://sourceware.org/pipermail/newlib/2020/018173.html
+	struct _reent *global_reent = _impure_ptr;
+	_impure_ptr = nullptr;
+	_reclaim_reent(global_reent);
+
 	__crt0_exit(ret);
 
 	__builtin_unreachable();

ndless-sdk/system/crt0.S

@@ -5,7 +5,6 @@ _start: .global _start
 	str  sp, __crt0_savedsp
 	push {r0, r1}
 	bl initialise_monitor_handles /* Grab stdin, -out and -err, required for newlib */
-	bl _init_signal /* Required for newlibs atexit */
 	bl __cpp_init /* C++ static initializers */
 	pop {r0, r1}
 	bl   main

ndless-sdk/system/crtn.S

@@ -6,9 +6,6 @@
 exit: .weak exit /* If linked without newlib, used by crt0. Can't be defined in crt0, as newlibs exit is also weak */
 	bl __crt0_exit
 
-_init_signal: .weak _init_signal /* Same here */
-	bx lr
- 
 .section .init_array
 	.long -1 /* Terminating character for ctor list */