Initial project import

tools/v/vlib/builtin/gc_debugger_linux.h

@@ -0,0 +1,55 @@
+#ifndef V_BUILTIN_GC_DEBUGGER_LINUX_H
+#define V_BUILTIN_GC_DEBUGGER_LINUX_H
+
+#if defined(__linux__)
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+#pragma weak __data_start
+#pragma weak data_start
+#pragma weak _end
+
+extern int __data_start[];
+extern int data_start[];
+extern int _end[];
+
+static inline int v__gc_can_register_main_data_roots_linux(void) {
+	void* data_start_ptr = __data_start != NULL ? (void*)__data_start : (void*)data_start;
+	void* data_end_ptr = (void*)_end;
+	return data_start_ptr != NULL && data_end_ptr != NULL && data_start_ptr < data_end_ptr;
+}
+
+static inline int v__gc_debugger_present_linux(void) {
+	int fd = open("/proc/self/status", O_RDONLY);
+	if (fd < 0) {
+		return 0;
+	}
+	char buf[4096];
+	ssize_t n = read(fd, buf, sizeof(buf) - 1);
+	(void)close(fd);
+	if (n <= 0) {
+		return 0;
+	}
+	buf[n] = '\0';
+	char* tracer_pid = strstr(buf, "TracerPid:");
+	if (tracer_pid == NULL) {
+		return 0;
+	}
+	tracer_pid += sizeof("TracerPid:") - 1;
+	while (*tracer_pid == ' ' || *tracer_pid == '\t') {
+		++tracer_pid;
+	}
+	return *tracer_pid != '0' && *tracer_pid != '\n' && *tracer_pid != '\0';
+}
+
+static inline void v__gc_register_main_data_roots_linux(void) {
+	if (!v__gc_can_register_main_data_roots_linux()) {
+		return;
+	}
+	void* data_start_ptr = __data_start != NULL ? (void*)__data_start : (void*)data_start;
+	GC_add_roots(data_start_ptr, (void*)_end);
+}
+#endif
+
+#endif