[PATCH] lib: define va_* for bootstrappable tcc in riscv

[Ekaitz Zarraga]

>From 925db8452301e1cae0db3b265791de626b736b2d Mon Sep 17 00:00:00 2001
From: Ekaitz Zarraga <ekaitz@elenq.tech>
Date: Wed, 11 Oct 2023 15:53:08 +0200
Subject: [PATCH] lib: define va_* for bootstrappable tcc in riscv

Bootstrappable TCC needs some extra definitions that upstream TCC
obtains from `tccdefs.h` in its codebase, which is also injected in the
binary using a weird trick (see `c2str` in tcc's codebase).

* include/stdarg.h: Add definitions for variable length arguments.
---
 include/stdarg.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/stdarg.h b/include/stdarg.h
index 090aebe1..98b168a9 100644
--- a/include/stdarg.h
+++ b/include/stdarg.h
@@ -32,6 +32,21 @@
 // GCC on RISC-V always passes arguments in registers. Implementing these 
macros without
 // the use of built-ins would be very involved.
 // TINYCC tries to be GCC compatible in this case.
+
+#if __TINYC__ < 928
+// Bootstrappable TINYCC (version < 928) needs some definitions in RISC-V
+typedef char *__builtin_va_list;
+#define __va_reg_size (__riscv_xlen >> 3)
+#define _tcc_align(addr,type) (((unsigned long)addr + __alignof__(type) - 1) \
+                              & -(__alignof__(type)))
+#define __builtin_va_arg(ap,type) (*(sizeof(type) > (2*__va_reg_size) ? *(type 
**)((ap += __va_reg_size) - __va_reg_size) : (ap = 
(va_list)(_tcc_align(ap,type) + (sizeof(type)+__va_reg_size - 1)& 
-__va_reg_size), (type *)(ap - ((sizeof(type)+ __va_reg_size - 1)& 
-__va_reg_size)))))
+
+#define __builtin_va_end(ap) (void)(ap)
+#ifndef __builtin_va_copy
+# define __builtin_va_copy(dest, src) (dest) = (src)
+#endif
+#endif
+
 typedef __builtin_va_list va_list;
 
 #define va_start(v,l)   __builtin_va_start(v,l)
-- 
2.41.0