v: add initial support for loongarch64 (#24343)

Author: tankf33der

vlib/v/gen/c/cheaders.v

@@ -171,6 +171,17 @@ static char __CLOSURE_GET_DATA_BYTES[] = {
 	0x66, 0x00, 0xc3, 0x7d,	// mfvsrd %r3, %f14
 	0x20, 0x00, 0x80, 0x4e,	// blr
 };
+#elif defined (__V_loongarch64)
+static char __closure_thunk[] = {
+	0x92, 0xFF, 0xFF, 0x1D,  // pcaddu12i t6, -4
+	0x48, 0x02, 0x80, 0x2B,  // fld.d     f8, t6, 0
+	0x51, 0x22, 0xC0, 0x28,  // ld.d      t5, t6, 8
+	0x20, 0x02, 0x00, 0x4C,  // jr        t5
+};
+static char __CLOSURE_GET_DATA_BYTES[] = {
+	0x04, 0xB9, 0x14, 0x01,  // movfr2gr.d a0, f8
+	0x20, 0x00, 0x00, 0x4C,  // ret
+};
 #endif
 
 static void*(*__CLOSURE_GET_DATA)(void) = 0;
@@ -357,6 +368,12 @@ const c_common_macros = '
 	#define __V_architecture 8
 #endif
 
+#if defined(__loongarch64)
+	#define __V_loongarch64  1
+	#undef __V_architecture
+	#define __V_architecture 9
+#endif
+
 // Using just __GNUC__ for detecting gcc, is not reliable because other compilers define it too:
 #ifdef __GNUC__
 	#define __V_GCC__
@@ -714,7 +731,7 @@ static void* g_live_info = NULL;
 
 const c_builtin_types = '
 //================================== builtin types ================================*/
-#if defined(__x86_64__) || defined(_M_AMD64) || defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64) || (defined(__riscv_xlen) && __riscv_xlen == 64) || defined(__s390x__) || (defined(__powerpc64__) && defined(__LITTLE_ENDIAN__))
+#if defined(__x86_64__) || defined(_M_AMD64) || defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64) || (defined(__riscv_xlen) && __riscv_xlen == 64) || defined(__s390x__) || (defined(__powerpc64__) && defined(__LITTLE_ENDIAN__)) || defined(__loongarch64)
 typedef int64_t vint_t;
 #else
 typedef int32_t vint_t;

vlib/v/gen/c/comptime.v

@@ -1302,6 +1302,9 @@ fn (mut g Gen) comptime_if_to_ifdef(name string, is_comptime_option bool) !strin
 		'ppc64le' {
 			return '__V_ppc64le'
 		}
+		'loongarch64' {
+			return '__V_loongarch64'
+		}
 		// bitness:
 		'x64' {
 			return 'TARGET_IS_64BIT'