[CoreCLR/NativeAOT] Migrate JNI reference logging to printf

src/native/clr/host/os-bridge.cc

@@ -1,4 +1,5 @@
-#include <ranges>
+#include <cstdarg>
+#include <cstdlib>
 
 #include <host/os-bridge.hh>
 #include <host/runtime-util.hh>
@@ -94,34 +95,40 @@ void OSBridge::_write_stack_trace (FILE *to, const char *const from, LogCategori
 		return;
 	}
 
-	const std::string_view trace { from };
+	std::string_view trace { from };
 	if (trace.empty ()) [[unlikely]] {
 		log_warn (category, "Empty stack trace passed by the managed runtime.");
 		return;
 	}
 
-	for (const auto segment : std::views::split (trace, '\n')) {
-		const std::string_view line { segment };
+	while (true) {
+		size_t line_end = trace.find ('\n');
+		size_t line_length = line_end == std::string_view::npos ? trace.length () : line_end;
+		std::string_view line { trace.data (), line_length };
 
 		if ((category == LOG_GREF && Logger::gref_to_logcat ()) ||
 			(category == LOG_LREF && Logger::lref_to_logcat ())) {
-				log_debug (category, "{}"sv, line);
+				log_debugf (category, "%.*s", static_cast<int>(line.length ()), line.data ());
 		}
 
-		if (to == nullptr) {
-			continue;
+		if (to != nullptr) {
+			fwrite (line.data (), sizeof (std::string_view::value_type), line.length (), to);
+			fputc ('\n', to);
+			fflush (to);
 		}
 
-		fwrite (line.data (), sizeof (std::string_view::value_type), line.length (), to);
-		fputc ('\n', to);
-		fflush (to);
+		if (line_end == std::string_view::npos) {
+			break;
+		}
+
+		trace.remove_prefix (line_end + 1);
 	}
 }
 
 void OSBridge::_monodroid_gref_log (const char *message) noexcept
 {
 	if (Logger::gref_to_logcat ()) {
-		log_debug (LOG_GREF, "{}"sv, optional_string (message));
+		log_debugf (LOG_GREF, "%s", optional_string (message));
 	}
 
 	if (Logger::gref_log () == nullptr) {
@@ -133,7 +140,7 @@ void OSBridge::_monodroid_gref_log (const char *message) noexcept
 }
 
 [[gnu::always_inline, gnu::flatten]]
-void OSBridge::log_it (LogCategories category, std::string const& line, FILE *to, const char *const from, bool logcat_enabled) noexcept
+void OSBridge::log_it (LogCategories category, std::string_view const& line, FILE *to, const char *const from, bool logcat_enabled) noexcept
 {
 	log_write (category, LogLevel::Info, line);
 
@@ -146,13 +153,31 @@ void OSBridge::log_it (LogCategories category, std::string const& line, FILE *to
 		return;
 	}
 
-	fwrite (line.c_str (), sizeof (std::string::value_type), line.length (), to);
+	fwrite (line.data (), sizeof (std::string_view::value_type), line.length (), to);
 	fputc ('\n', to);
 
 	_write_stack_trace (to, from, category);
 	fflush (to);
 }
 
+void OSBridge::log_itf (LogCategories category, FILE *to, const char *const from, bool logcat_enabled, const char *format, ...) noexcept
+{
+	const char *safe_format = format == nullptr ? "<null>" : format;
+	char *line = nullptr;
+	va_list args;
+	va_start (args, format);
+	int length = vasprintf (&line, safe_format, args);
+	va_end (args);
+
+	if (length < 0) [[unlikely]] {
+		log_it (category, safe_format, to, from, logcat_enabled);
+		return;
+	}
+
+	log_it (category, std::string_view { line, static_cast<size_t>(length) }, to, from, logcat_enabled);
+	std::free (line);
+}
+
 auto OSBridge::_monodroid_gref_log_new (jobject curHandle, char curType, jobject newHandle, char newType, const char *threadName, int threadId, const char *from) noexcept -> int
 {
 	int c = _monodroid_gref_inc ();
@@ -161,8 +186,12 @@ auto OSBridge::_monodroid_gref_log_new (jobject curHandle, char curType, jobject
 	}
 
 	int wc = __atomic_load_n (&gc_weak_gref_count, __ATOMIC_RELAXED);
-	const std::string log_line = std::format (
-		"+g+ grefc {} gwrefc {} obj-handle {:p}/{} -> new-handle {:p}/{} from thread '{}'({})"sv,
+	log_itf (
+		LOG_GREF,
+		Logger::gref_log (),
+		from,
+		Logger::gref_to_logcat (),
+		"+g+ grefc %d gwrefc %d obj-handle %p/%c -> new-handle %p/%c from thread '%s'(%d)",
 		c,
 		wc,
 		reinterpret_cast<void*>(curHandle),
@@ -172,8 +201,6 @@ auto OSBridge::_monodroid_gref_log_new (jobject curHandle, char curType, jobject
 		optional_string (threadName),
 		threadId
 	);
-
-	log_it (LOG_GREF, log_line, Logger::gref_log (), from, Logger::gref_to_logcat ());
 	return c;
 }
 
@@ -185,17 +212,19 @@ void OSBridge::_monodroid_gref_log_delete (jobject handle, char type, const char
 	}
 
 	int wc = __atomic_load_n (&gc_weak_gref_count, __ATOMIC_RELAXED);
-	const std::string log_line = std::format (
-		"-g- grefc {} gwrefc {} handle {:p}/{} from thread '{}'({})"sv,
+	log_itf (
+		LOG_GREF,
+		Logger::gref_log (),
+		from,
+		Logger::gref_to_logcat (),
+		"-g- grefc %d gwrefc %d handle %p/%c from thread '%s'(%d)",
 		c,
 		wc,
 		reinterpret_cast<void*>(handle),
 		type,
 		optional_string (threadName),
 		threadId
 	);
-
-	log_it (LOG_GREF, log_line, Logger::gref_log (), from, Logger::gref_to_logcat ());
 }
 
 void OSBridge::_monodroid_weak_gref_new (jobject curHandle, char curType, jobject newHandle, char newType, const char *threadName, int threadId, const char *from)
@@ -206,8 +235,12 @@ void OSBridge::_monodroid_weak_gref_new (jobject curHandle, char curType, jobjec
 	}
 
 	int gc = __atomic_load_n (&gc_gref_count, __ATOMIC_RELAXED);
-	const std::string log_line = std::format (
-		"+w+ grefc {} gwrefc {} obj-handle {:p}/{} -> new-handle {:p}/{} from thread '{}'({})"sv,
+	log_itf (
+		LOG_GREF,
+		Logger::gref_log (),
+		from,
+		Logger::gref_to_logcat (),
+		"+w+ grefc %d gwrefc %d obj-handle %p/%c -> new-handle %p/%c from thread '%s'(%d)",
 		gc,
 		c,
 		reinterpret_cast<void*>(curHandle),
@@ -217,8 +250,6 @@ void OSBridge::_monodroid_weak_gref_new (jobject curHandle, char curType, jobjec
 		optional_string (threadName),
 		threadId
 	);
-
-	log_it (LOG_GREF, log_line, Logger::gref_log (), from, Logger::gref_to_logcat ());
 }
 
 void
@@ -228,16 +259,18 @@ OSBridge::_monodroid_lref_log_new (int lrefc, jobject handle, char type, const c
 		return;
 	}
 
-	const std::string log_line = std::format (
-		"+l+ lrefc {} handle {:p}/{} from thread '{}'({})"sv,
+	log_itf (
+		LOG_LREF,
+		Logger::lref_log (),
+		from,
+		Logger::lref_to_logcat (),
+		"+l+ lrefc %d handle %p/%c from thread '%s'(%d)",
 		lrefc,
 		reinterpret_cast<void*>(handle),
 		type,
 		optional_string (threadName),
 		threadId
 	);
-
-	log_it (LOG_LREF, log_line, Logger::lref_log (), from, Logger::lref_to_logcat ());
 }
 
 void OSBridge::_monodroid_weak_gref_delete (jobject handle, char type, const char *threadName, int threadId, const char *from)
@@ -248,17 +281,19 @@ void OSBridge::_monodroid_weak_gref_delete (jobject handle, char type, const cha
 	}
 
 	int gc = __atomic_load_n (&gc_gref_count, __ATOMIC_RELAXED);
-	const std::string log_line = std::format (
-		"-w- grefc {} gwrefc {} handle {:p}/{} from thread '{}'({})"sv,
+	log_itf (
+		LOG_GREF,
+		Logger::gref_log (),
+		from,
+		Logger::gref_to_logcat (),
+		"-w- grefc %d gwrefc %d handle %p/%c from thread '%s'(%d)",
 		gc,
 		c,
 		reinterpret_cast<void*>(handle),
 		type,
 		optional_string (threadName),
 		threadId
 	);
-
-	log_it (LOG_GREF, log_line, Logger::gref_log (), from, Logger::gref_to_logcat ());
 }
 
 void OSBridge::_monodroid_lref_log_delete (int lrefc, jobject handle, char type, const char *threadName, int threadId, const char *from)
@@ -267,14 +302,16 @@ void OSBridge::_monodroid_lref_log_delete (int lrefc, jobject handle, char type,
 		return;
 	}
 
-	const std::string log_line = std::format (
-		"-l- lrefc {} handle {:p}/{} from thread '{}'({})"sv,
+	log_itf (
+		LOG_LREF,
+		Logger::lref_log (),
+		from,
+		Logger::lref_to_logcat (),
+		"-l- lrefc %d handle %p/%c from thread '%s'(%d)",
 		lrefc,
 		reinterpret_cast<void*>(handle),
 		type,
 		optional_string (threadName),
 		threadId
 	);
-
-	log_it (LOG_LREF, log_line, Logger::lref_log (), from, Logger::lref_to_logcat ());
 }

src/native/clr/include/host/os-bridge.hh

@@ -1,6 +1,8 @@
 #pragma once
 
+#include <cstdarg>
 #include <cstdio>
+#include <string_view>
 
 #include <jni.h>
 
@@ -57,7 +59,8 @@ namespace xamarin::android {
 
 	private:
 		static void _write_stack_trace (FILE *to, const char *const from, LogCategories = LOG_NONE) noexcept;
-		static void log_it (LogCategories category, std::string const& line, FILE *to, const char *const from, bool logcat_enabled) noexcept;
+		static void log_it (LogCategories category, std::string_view const& line, FILE *to, const char *const from, bool logcat_enabled) noexcept;
+		static void log_itf (LogCategories category, FILE *to, const char *const from, bool logcat_enabled, const char *format, ...) noexcept __attribute__ ((format (printf, 5, 6)));
 
 	private:
 		static inline JavaVM *jvm = nullptr;

src/native/clr/include/shared/log_types.hh

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdarg>
 #include <cstdint>
 #include <format>
 #include <string>
@@ -47,6 +48,12 @@ namespace xamarin::android {
 	// A slightly faster alternative to other log functions as it doesn't parse the message
 	// for format placeholders nor it uses variable arguments
 	void log_write (LogCategories category, LogLevel level, const char *message) noexcept;
+	void log_writev (LogCategories category, LogLevel level, const char *format, va_list args) noexcept;
+	void log_writef (LogCategories category, LogLevel level, const char *format, ...) noexcept __attribute__ ((format (printf, 3, 4)));
+	void log_debugf (LogCategories category, const char *format, ...) noexcept __attribute__ ((format (printf, 2, 3)));
+	void log_infof (LogCategories category, const char *format, ...) noexcept __attribute__ ((format (printf, 2, 3)));
+	void log_warnf (LogCategories category, const char *format, ...) noexcept __attribute__ ((format (printf, 2, 3)));
+	void log_errorf (LogCategories category, const char *format, ...) noexcept __attribute__ ((format (printf, 2, 3)));
 
 	[[gnu::always_inline]]
 	static inline void log_write (LogCategories category, LogLevel level, std::string_view const& message) noexcept

src/native/clr/shared/helpers.cc

@@ -1,4 +1,5 @@
 #include <cstdarg>
+#include <cstdio>
 #include <cstring>
 #include <android/set_abort_message.h>
 
@@ -7,11 +8,24 @@
 
 using namespace xamarin::android;
 
+[[noreturn]] void
+Helpers::abort_applicationf (LogCategories category, std::source_location sloc, const char *format, ...) noexcept
+{
+	char *message = nullptr;
+	const char *safe_format = format == nullptr ? "<null>" : format;
+	va_list args;
+	va_start (args, format);
+	int ret = vasprintf (&message, safe_format, args);
+	va_end (args);
+
+	abort_application (category, ret < 0 ? safe_format : message, true, sloc);
+}
+
 [[noreturn]] void
 Helpers::abort_application (LogCategories category, const char *message, bool log_location, std::source_location sloc) noexcept
 {
 	// Log it, but also...
-	log_fatal (category, "{}", message);
+	log_write (category, LogLevel::Fatal, message);
 
 	// ...let android include it in the tombstone, debuggerd output, stack trace etc
 	android_set_abort_message (message);
@@ -33,9 +47,10 @@ Helpers::abort_application (LogCategories category, const char *message, bool lo
 			}
 		}
 
-		log_fatal (
+		log_writef (
 			category,
-			"Abort at {}:{}:{} ('{}')",
+			LogLevel::Fatal,
+			"Abort at %s:%u:%u ('%s')",
 			file_name,
 			sloc.line (),
 			sloc.column (),