From 472f0acc544660088248ea27cfc9c2105b4ca665 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Mon, 29 Jun 2026 01:51:50 +0300
Subject: [PATCH] v3: fix self host

---
 vlib/v3/gen/c/cleanc.v                        |  6 +++
 vlib/v3/gen/c/fn.v                            | 52 +++++++++++++++++++
 .../v3/tests/c_directive_order_codegen_test.v | 16 +++++-
 .../v3/tests/posix_wait_header_codegen_test.v |  1 +
 4 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/vlib/v3/gen/c/cleanc.v b/vlib/v3/gen/c/cleanc.v
index ec7c3e005..4d03431ab 100644
--- a/vlib/v3/gen/c/cleanc.v
+++ b/vlib/v3/gen/c/cleanc.v
@@ -766,6 +766,9 @@ fn c_preserved_system_include_declared_fns(include_arg string) []string {
 		'<dlfcn.h>' {
 			return ['dlopen', 'dlsym', 'dlclose', 'dlerror']
 		}
+		'<mach/mach_time.h>' {
+			return ['mach_absolute_time', 'mach_timebase_info']
+		}
 		else {
 			return []string{}
 		}
@@ -774,6 +777,9 @@ fn c_preserved_system_include_declared_fns(include_arg string) []string {
 
 fn c_preserved_system_include_struct_names(include_arg string) []string {
 	match include_arg.trim_space() {
+		'<mach/mach_time.h>' {
+			return ['mach_timebase_info_data_t']
+		}
 		'<X11/Xlib.h>', '<X11/Xutil.h>', '<X11/Xresource.h>', '<X11/XKBlib.h>',
 		'<X11/extensions/XInput2.h>', '<X11/Xcursor/Xcursor.h>' {
 			return c_x11_preserved_struct_names.clone()
diff --git a/vlib/v3/gen/c/fn.v b/vlib/v3/gen/c/fn.v
index 95294023b..6b7f1b436 100644
--- a/vlib/v3/gen/c/fn.v
+++ b/vlib/v3/gen/c/fn.v
@@ -3907,6 +3907,9 @@ fn (g &FlatGen) should_emit_c_extern_decl(cfn string) bool {
 	if cfn.contains('.') {
 		return false
 	}
+	if cfn in c_preamble_declared_extern_symbols {
+		return false
+	}
 	if cfn in c_static_helper_symbols {
 		return false
 	}
@@ -3919,6 +3922,55 @@ fn (g &FlatGen) should_emit_c_extern_decl(cfn string) bool {
 	return true
 }
 
+const c_preamble_declared_extern_symbols = {
+	'_exit':                 true
+	'__errno':               true
+	'__errno_location':      true
+	'__error':               true
+	'_errno':                true
+	'abort':                 true
+	'access':                true
+	'atexit':                true
+	'ceil':                  true
+	'ceilf':                 true
+	'close':                 true
+	'cos':                   true
+	'dup2':                  true
+	'execlp':                true
+	'execvp':                true
+	'fabs':                  true
+	'fcntl':                 true
+	'floor':                 true
+	'floorf':                true
+	'fmod':                  true
+	'fork':                  true
+	'getenv':                true
+	'ldexp':                 true
+	'memcmp':                true
+	'memcpy':                true
+	'memmove':               true
+	'memset':                true
+	'open':                  true
+	'pipe':                  true
+	'pow':                   true
+	'pthread_mutex_destroy': true
+	'pthread_mutex_init':    true
+	'pthread_mutex_lock':    true
+	'pthread_mutex_unlock':  true
+	'read':                  true
+	'realpath':              true
+	'setenv':                true
+	'signal':                true
+	'snprintf':              true
+	'sqrt':                  true
+	'strcmp':                true
+	'strlen':                true
+	'strncmp':               true
+	'strncpy':               true
+	'strrchr':               true
+	'strstr':                true
+}
+
 const c_static_helper_symbols = {
 	'EV_SET':                              true
 	'FD_ISSET':                            true
diff --git a/vlib/v3/tests/c_directive_order_codegen_test.v b/vlib/v3/tests/c_directive_order_codegen_test.v
index 34feb2ba7..367101a68 100644
--- a/vlib/v3/tests/c_directive_order_codegen_test.v
+++ b/vlib/v3/tests/c_directive_order_codegen_test.v
@@ -677,7 +677,18 @@ fn directive_order_gen_c_preserved_mach_headers(v3_bin string) string {
 #include <mach/mach.h>
 #include <mach/mach_time.h>
 
-fn main() {}
+@[typedef]
+struct C.mach_timebase_info_data_t {
+	numer u32
+	denom u32
+}
+
+fn C.mach_timebase_info(&C.mach_timebase_info_data_t)
+
+fn main() {
+	mut tb := C.mach_timebase_info_data_t{}
+	C.mach_timebase_info(&tb)
+}
 ')
 	c_out := os.join_path(os.temp_dir(), 'v3_c_directive_order_mach.c')
 	os.rm(c_out) or {}
@@ -1013,6 +1024,9 @@ fn test_preserved_mach_headers_are_wrapped_with_panic_alias() {
 	assert c_code.contains('#define panic mach_panic\n#include <mach/mach.h>\n#undef panic'), c_code
 	assert c_code.contains('#define panic mach_panic\n#include <mach/mach_time.h>\n#undef panic'), c_code
 	assert directive_order_index(c_code, '#undef panic') < preamble_idx, c_code
+	assert !c_code.contains('typedef struct mach_timebase_info_data_t mach_timebase_info_data_t;'), c_code
+
+	assert directive_order_count(c_code, 'mach_timebase_info(') == 1, c_code
 }
 
 fn test_stdarg_in_inlined_header_uses_headerless_va_defs() {
diff --git a/vlib/v3/tests/posix_wait_header_codegen_test.v b/vlib/v3/tests/posix_wait_header_codegen_test.v
index 44f6935da..04504609c 100644
--- a/vlib/v3/tests/posix_wait_header_codegen_test.v
+++ b/vlib/v3/tests/posix_wait_header_codegen_test.v
@@ -95,6 +95,7 @@ fn main() {
 	assert with_os.c_code.contains('void* memmove(void* dest, const void* src, size_t n);'), with_os.c_code
 	assert with_os.c_code.contains('int memcmp(const void* s1, const void* s2, size_t n);'), with_os.c_code
 	assert with_os.c_code.contains('size_t strlen(const char* s);'), with_os.c_code
+	assert !with_os.c_code.contains('i32 strlen(char* s);'), with_os.c_code
 	assert with_os.c_code.contains('int strcmp(const char* s1, const char* s2);'), with_os.c_code
 	assert with_os.c_code.contains('int strncmp(const char* s1, const char* s2, size_t n);'), with_os.c_code
 	assert with_os.c_code.contains('char* strncpy(char* dest, const char* src, size_t n);'), with_os.c_code
-- 
2.39.5