cgen: preserve standalone poll and native-cache helpers

vlib/v/driver/driver.v

@@ -8080,6 +8080,7 @@ const v3_cache_compiler_runtime_inputs = [
 	'vlib/builtin/segfault_handler_nix.c',
 	'vlib/builtin/segfault_handler_nix.h',
 	'vlib/v/driver/run_signals_nix.c',
+	'vlib/v/driver/native_object_cache_impl.c',
 	'vlib/builtin/core_windows.c',
 	'vlib/builtin/core_windows.h',
 	'vlib/time/ticks_windows.c',

vlib/v/driver/native_object_cache.h

@@ -22,46 +22,6 @@ long syscall(long, ...);
 #include <sys/syscall.h>
 #endif
 
-/* Use the syscall: Bionic's renameat2 wrapper is unavailable before API 30.
- * Keep these guards in C so a portable vc snapshot can build on other hosts. */
-static inline int v_native_object_cache_rename_noreplace(const char *source, const char *destination) {
-#if defined(__linux__) && defined(SYS_renameat2)
-	/* Linux AT_FDCWD is -100 and RENAME_NOREPLACE is 1. Avoid importing fcntl
-	 * types into headerless snapshots or requiring the flag in old headers. */
-	if (syscall(SYS_renameat2, -100, source, -100, destination, 1U) == 0) {
-		return 0;
-	}
-	return errno;
-#else
-	(void)source;
-	(void)destination;
-	return ENOSYS;
-#endif
-}
-
-static inline int v_native_object_cache_publish(const char *source, const char *destination) {
-#ifndef _WIN32
-#ifdef V_NATIVE_OBJECT_CACHE_HEADERLESS
-	if (link((char *)source, (char *)destination) == 0) {
-#else
-	if (link(source, destination) == 0) {
-#endif
-		return 0;
-	}
-	const int code = errno;
-#if defined(__linux__)
-	/* Android SELinux can forbid links in app-private storage; some filesystems
-	 * do not implement hard links. Neither prevents an atomic no-replace rename. */
-	if (code == EACCES || code == EPERM || code == EOPNOTSUPP) {
-		return v_native_object_cache_rename_noreplace(source, destination);
-	}
-#endif
-	return code;
-#else
-	(void)source;
-	(void)destination;
-	return ENOSYS;
-#endif
-}
+#include "native_object_cache_impl.c"
 
 #endif

vlib/v/driver/native_object_cache_impl.c

@@ -0,0 +1,84 @@
+/* Shared by the SDK-backed header and standalone compiler snapshots. */
+#ifndef V_NATIVE_OBJECT_CACHE_IMPL
+#define V_NATIVE_OBJECT_CACHE_IMPL
+
+#if defined(ENOSYS)
+#define V_NATIVE_OBJECT_CACHE_ENOSYS ENOSYS
+#elif defined(__linux__)
+#define V_NATIVE_OBJECT_CACHE_ENOSYS 38
+#elif defined(_WIN32)
+#define V_NATIVE_OBJECT_CACHE_ENOSYS 40
+#else
+#define V_NATIVE_OBJECT_CACHE_ENOSYS 78
+#endif
+
+#if defined(__linux__)
+#if defined(EOPNOTSUPP)
+#define V_NATIVE_OBJECT_CACHE_EOPNOTSUPP EOPNOTSUPP
+#else
+#define V_NATIVE_OBJECT_CACHE_EOPNOTSUPP 95
+#endif
+/* Linux UAPI syscall tables: x86, arm, asm-generic, powerpc and s390.
+ * Native headers remain authoritative when the SDK provides the number. */
+#if defined(SYS_renameat2)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 SYS_renameat2
+#elif defined(__x86_64__) && defined(__ILP32__)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 (0x40000000 + 316)
+#elif defined(__x86_64__)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 316
+#elif defined(__i386__)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 353
+#elif defined(__arm__)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 382
+#elif defined(__aarch64__) || defined(__riscv) || defined(__loongarch__)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 276
+#elif defined(__powerpc__)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 357
+#elif defined(__s390__)
+#define V_NATIVE_OBJECT_CACHE_RENAMEAT2 347
+#endif
+#endif
+
+/* Use the syscall: Bionic's renameat2 wrapper is unavailable before API 30.
+ * Keep these guards in C so a portable vc snapshot can build on other hosts. */
+static inline int v_native_object_cache_rename_noreplace(const char *source, const char *destination) {
+#if defined(__linux__) && defined(V_NATIVE_OBJECT_CACHE_RENAMEAT2)
+	/* Linux AT_FDCWD is -100 and RENAME_NOREPLACE is 1. Avoid importing fcntl
+	 * types into headerless snapshots or requiring the flag in old headers. */
+	if (syscall(V_NATIVE_OBJECT_CACHE_RENAMEAT2, -100, source, -100, destination, 1U) == 0) {
+		return 0;
+	}
+	return errno;
+#else
+	(void)source;
+	(void)destination;
+	return V_NATIVE_OBJECT_CACHE_ENOSYS;
+#endif
+}
+
+static inline int v_native_object_cache_publish(const char *source, const char *destination) {
+#ifndef _WIN32
+#ifdef V_NATIVE_OBJECT_CACHE_HEADERLESS
+	if (link((char *)source, (char *)destination) == 0) {
+#else
+	if (link(source, destination) == 0) {
+#endif
+		return 0;
+	}
+	const int code = errno;
+#if defined(__linux__)
+	/* Android SELinux can forbid links in app-private storage; some filesystems
+	 * do not implement hard links. Neither prevents an atomic no-replace rename. */
+	if (code == EACCES || code == EPERM || code == V_NATIVE_OBJECT_CACHE_EOPNOTSUPP) {
+		return v_native_object_cache_rename_noreplace(source, destination);
+	}
+#endif
+	return code;
+#else
+	(void)source;
+	(void)destination;
+	return V_NATIVE_OBJECT_CACHE_ENOSYS;
+#endif
+}
+
+#endif

vlib/v/gen/c/bootstrap_runtime.v

@@ -1,5 +1,24 @@
 module c
 
+// headerless_native_object_cache_helper supplies the shipped publication helper
+// without importing SDK headers into a standalone compiler translation unit.
+fn (mut g FlatGen) headerless_native_object_cache_helper() {
+	root := g.compiler_vroot.replace('\\', '/').trim_right('/')
+	if !g.core_header_directives.any(normalized_c_include_arg_path(it.directive.text.all_after('#include').trim_space()) == root + '/vlib/v/driver/native_object_cache.h') {
+		return
+	}
+	g.writeln('#define V_NATIVE_OBJECT_CACHE_HEADERLESS 1')
+	g.writeln('#ifndef _WIN32')
+	g.writeln(g.cpp_c_linkage('int link(char*, char*);'))
+	g.writeln('#if defined(__linux__)')
+	g.writeln(g.cpp_c_linkage('long syscall(long, ...);'))
+	g.writeln('#endif')
+	g.writeln('#endif')
+	g.write($embed_file('@VEXEROOT/vlib/v/driver/native_object_cache_impl.c').to_string())
+	g.collect_preserved_c_fns(['v_native_object_cache_publish', 'v_native_object_cache_rename_noreplace',
+		'link', 'syscall'])
+}
+
 // portable_windows_runtime_helpers embeds SDK-backed helpers without checkout-local objects.
 fn (mut g FlatGen) portable_windows_runtime_helpers() {
 	g.writeln('#ifdef _WIN32')
@@ -134,14 +153,21 @@ static inline int v_sync_thread_create_detached(void* start, void* arg) {
 }
 '
 
-// headerless_cmdexec_poll_helper replaces only the shipped poll header when the
+// headerless_cmdexec_poll_helper replaces the shipped poll headers when the
 // standalone ABI owns libc declarations; SDK-backed units keep the native helper.
 fn (mut g FlatGen) headerless_cmdexec_poll_helper() {
-	if g.target.os == 'windows' || !g.core_header_directives.any(it.directive.module == 'cmdexec') {
+	os_poll := g.core_header_directives.any(it.directive.module == 'os'
+		&& normalized_c_include_arg_path(it.directive.text.all_after('#include').trim_space()) == g.compiler_vroot.replace('\\', '/').trim_right('/') + '/vlib/os/fd_poll.h')
+	if g.target.os == 'windows'
+		|| (!os_poll && !g.core_header_directives.any(it.directive.module == 'cmdexec')) {
 		return
 	}
 	g.write(headerless_cmdexec_poll)
 	g.collect_preserved_c_fns(['v_cmdexec_poll_revents'])
+	if os_poll {
+		g.writeln('static inline short v_os_fd_poll_revents(int fd, short events) { return v_cmdexec_poll_revents(fd, events); }')
+		g.collect_preserved_c_fns(['v_os_fd_poll_revents'])
+	}
 }
 
 const headerless_cmdexec_poll = r'

vlib/v/gen/c/cleanc.v

@@ -6763,7 +6763,12 @@ fn (g &FlatGen) core_native_source_header_is_redeclared(root string, source stri
 				|| normalized_c_include_arg_path(include_arg) == root + '/vlib/builtin/core_windows.h'
 		}
 		'builtin/closure/closure_windows.c.v' { return include_arg == '<synchapi.h>' }
-		'os/fd.c.v' { return include_arg in ['<winsock2.h>', '<poll.h>'] }
+		'os/fd.c.v' {
+			return include_arg in ['<winsock2.h>', '<poll.h>']
+				|| (g.target.os in ['macos', 'linux', 'android', 'termux', 'freebsd', 'openbsd',
+					'dragonfly', 'ios']
+					&& normalized_c_include_arg_path(include_arg) == root + '/vlib/os/fd_poll.h')
+		}
 		'os/mmap_nix.c.v' {
 			return g.target.pointer_bits == 64 && g.target.os in ['macos', 'linux', 'android',
 				'termux', 'freebsd', 'openbsd', 'dragonfly']
@@ -6775,6 +6780,9 @@ fn (g &FlatGen) core_native_source_header_is_redeclared(root string, source stri
 		'v/driver/replace_file_windows.c.v' {
 			return include_arg == '<windows.h>'
 		}
+		'v/driver/native_object_cache.c.v' {
+			return normalized_c_include_arg_path(include_arg) == root + '/vlib/v/driver/native_object_cache.h'
+		}
 		'v/cmdexec/cmdexec_pipe.c.v' {
 			return include_arg == '<windows.h>'
 				|| (g.target.os in ['macos', 'linux', 'android', 'termux', 'freebsd', 'openbsd',
@@ -7127,7 +7135,10 @@ fn (mut g FlatGen) collect_c_directive_at(node_idx int, module_name string, node
 			}
 		}
 		include_dirs := c_flag_include_dirs(g.c_flags)
-		if node.value == 'include' && g.core_native_header_is_redeclared(source_file, include_arg) {
+		native_cache_insert := node.value == 'insert'
+			&& normalized_c_include_arg_path(include_arg) == g.compiler_vroot.replace('\\', '/').trim_right('/') + '/vlib/v/driver/native_object_cache.h'
+		if (node.value == 'include' || native_cache_insert)
+			&& g.core_native_header_is_redeclared(source_file, include_arg) {
 			// Native objects still compile against their SDK; only the generated V
 			// translation unit uses the bodyless declarations and ABI preamble.
 			g.add_native_source_context_directive(module_name, c_native_source_context_header_include(include_arg, g.compiler_vroot, source_file, include_dirs), before_import)
@@ -20716,6 +20727,7 @@ fn (mut g FlatGen) preamble() {
 	} else {
 		g.headerless_libc_preamble()
 		g.headerless_cmdexec_poll_helper()
+		g.headerless_native_object_cache_helper()
 		if g.headerless_compiler_bootstrap() {
 			g.portable_native_runtime_helpers()
 		}

vlib/v/gen/c/cpp_compat_test.v

@@ -291,3 +291,43 @@ int main() {
 		assert ran.exit_code == 0, ran.output
 	}
 }
+
+fn test_cpp_headerless_native_cache_libc_linkage() {
+	$if windows {
+		return
+	}
+	cpp := cpp_test_compiler() or { return }
+	root := os.join_path(os.vtmp_dir(), 'cpp_native_cache_${os.getpid()}')
+	os.mkdir_all(root)!
+	defer { os.rmdir_all(root) or {} }
+	mut g := cpp_test_gen()
+	g.compiler_vroot = @VEXEROOT
+	g.core_header_directives << DeferredCoreHeader{
+		source_file: os.join_path(@VEXEROOT, 'vlib/v/driver/native_object_cache.c.v')
+		directive:   CDirective{ module: 'driver', text: '#include "' + @VEXEROOT + '/vlib/v/driver/native_object_cache.h"' }
+	}
+	g.headerless_native_object_cache_helper()
+	source := os.join_path(root, 'main.cpp')
+	os.write_file(source, '#include <errno.h>
+${g.sb.str()}
+// Match the later gettid compatibility declaration in a compiler translation unit.
+#ifdef __linux__
+extern "C" { long syscall(long, ...); }
+#endif
+int main(int argc, char** argv) {
+ if (argc != 3) return 1;
+ if (v_native_object_cache_publish(argv[1], argv[2]) != ENOENT) return 2;
+#ifdef __linux__
+ if (v_native_object_cache_rename_noreplace(argv[1], argv[2]) != ENOENT) return 3;
+#endif
+ return 0;
+}
+')!
+	for standard in cpp_test_standards() {
+		binary := os.join_path(root, 'program')
+		built := cmdexec.run(cpp, ['-std=${standard}', source, '-o', binary])
+		assert built.exit_code == 0, built.output
+		ran := cmdexec.run(binary, [os.join_path(root, 'missing'), os.join_path(root, 'destination')])
+		assert ran.exit_code == 0, ran.output
+	}
+}

vlib/v/gen/c/mmap_headerless_test.v

@@ -84,10 +84,16 @@ fn test_mmap_header_ownership_holds_for_a_cached_header_of_the_whole_module() {
 	]
 	assert g.core_native_header_is_redeclared('/cache/cmdexec.vh', poll_h)
 	assert !g.core_native_header_is_redeclared('/cache/cmdexec.vh', '<poll.h>')
+	os_poll_h := '"/vroot/vlib/os/fd_poll.h"'
+	a.cached_header_module_sources['/cache/os.vh'] << '/vroot/vlib/os/fd.c.v'
+	assert g.core_native_header_is_redeclared('/cache/os.vh', os_poll_h)
+	assert !g.core_native_header_is_redeclared('/cache/other.vh', os_poll_h)
+	assert !g.core_native_header_is_redeclared('/project/os/fd.c.v', os_poll_h)
 	// The SDK modes keep every include of a cached header too.
 	g.no_builtin = true
 	assert !g.core_native_header_is_redeclared('/cache/os.vh', '<sys/mman.h>')
 	assert !g.core_native_header_is_redeclared('/cache/cmdexec.vh', poll_h)
+	assert !g.core_native_header_is_redeclared('/cache/os.vh', os_poll_h)
 	g.no_builtin = false
 	g.output_cross_c = true
 	assert !g.core_native_header_is_redeclared('/cache/os.vh', '<sys/mman.h>')