[common/logging] faster logging by avoiding constructing unused strings/results (and filtering first) (#2603)

basically std::string would be invoked even when the logging was filtered, then destroyed instantly, invoking malloc/free and polluting mem arenas for no good reason

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2603
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

src/common/logging/backend.cpp

@@ -39,9 +39,17 @@ namespace Common::Log {
 
 namespace {
 
-/**
- * Interface for logging backends.
- */
+/// @brief Trims up to and including the last of ../, ..\, src/, src\ in a string
+/// do not be fooled this isn't generating new strings on .rodata :)
+constexpr const char* TrimSourcePath(std::string_view source) {
+    const auto rfind = [source](const std::string_view match) {
+        return source.rfind(match) == source.npos ? 0 : (source.rfind(match) + match.size());
+    };
+    auto idx = (std::max)({rfind("src/"), rfind("src\\"), rfind("../"), rfind("..\\")});
+    return source.data() + idx;
+}
+
+/// @brief Interface for logging backends.
 class Backend {
 public:
     virtual ~Backend() = default;
@@ -53,9 +61,7 @@ public:
     virtual void Flush() = 0;
 };
 
-/**
- * Backend that writes to stderr and with color
- */
+/// @brief Backend that writes to stderr and with color
 class ColorConsoleBackend final : public Backend {
 public:
     explicit ColorConsoleBackend() = default;
@@ -84,9 +90,7 @@ private:
     std::atomic_bool enabled{false};
 };
 
-/**
- * Backend that writes to a file passed into the constructor
- */
+/// @brief Backend that writes to a file passed into the constructor
 class FileBackend final : public Backend {
 public:
     explicit FileBackend(const std::filesystem::path& filename) {
@@ -248,13 +252,14 @@ public:
         color_console_backend.SetEnabled(enabled);
     }
 
-    void PushEntry(Class log_class, Level log_level, const char* filename, unsigned int line_num,
-                   const char* function, std::string&& message) {
-        if (!filter.CheckMessage(log_class, log_level)) {
-            return;
+    bool CanPushEntry(Class log_class, Level log_level) const noexcept {
+        return filter.CheckMessage(log_class, log_level);
     }
+
+    void PushEntry(Class log_class, Level log_level, const char* filename, unsigned int line_num,
+                   const char* function, std::string&& message) noexcept {
         message_queue.EmplaceWait(
-            CreateEntry(log_class, log_level, filename, line_num, function, std::move(message)));
+            CreateEntry(log_class, log_level, TrimSourcePath(filename), line_num, function, std::move(message)));
     }
 
 private:
@@ -368,8 +373,9 @@ void FmtLogMessageImpl(Class log_class, Level log_level, const char* filename,
                        unsigned int line_num, const char* function, fmt::string_view format,
                        const fmt::format_args& args) {
     if (!initialization_in_progress_suppress_logging) {
-        Impl::Instance().PushEntry(log_class, log_level, filename, line_num, function,
-                                   fmt::vformat(format, args));
+        auto& instance = Impl::Instance();
+        if (instance.CanPushEntry(log_class, log_level))
+            instance.PushEntry(log_class, log_level, filename, line_num, function, fmt::vformat(format, args));
     }
 }
 } // namespace Common::Log

src/common/logging/filter.cpp

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: 2014 Citra Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -9,22 +12,20 @@ namespace Common::Log {
 namespace {
 template <typename It>
 Level GetLevelByName(const It begin, const It end) {
-    for (u8 i = 0; i < static_cast<u8>(Level::Count); ++i) {
-        const char* level_name = GetLevelName(static_cast<Level>(i));
-        if (Common::ComparePartialString(begin, end, level_name)) {
-            return static_cast<Level>(i);
-        }
+    for (u32 i = 0; i < u32(Level::Count); ++i) {
+        const char* level_name = GetLevelName(Level(i));
+        if (Common::ComparePartialString(begin, end, level_name))
+            return Level(i);
     }
     return Level::Count;
 }
 
 template <typename It>
 Class GetClassByName(const It begin, const It end) {
-    for (u8 i = 0; i < static_cast<u8>(Class::Count); ++i) {
-        const char* level_name = GetLogClassName(static_cast<Class>(i));
-        if (Common::ComparePartialString(begin, end, level_name)) {
-            return static_cast<Class>(i);
-        }
+    for (u32 i = 0; i < u32(Class::Count); ++i) {
+        const char* level_name = GetLogClassName(Class(i));
+        if (Common::ComparePartialString(begin, end, level_name))
+            return Class(i);
     }
     return Class::Count;
 }
@@ -229,13 +230,12 @@ void Filter::ParseFilterString(std::string_view filter_view) {
 }
 
 bool Filter::CheckMessage(Class log_class, Level level) const {
-    return static_cast<u8>(level) >=
-           static_cast<u8>(class_levels[static_cast<std::size_t>(log_class)]);
+    return u8(level) >= u8(class_levels[std::size_t(log_class)]);
 }
 
 bool Filter::IsDebug() const {
     return std::any_of(class_levels.begin(), class_levels.end(), [](const Level& l) {
-        return static_cast<u8>(l) <= static_cast<u8>(Level::Debug);
+        return u8(l) <= u8(Level::Debug);
     });
 }
 

src/common/logging/log.h

@@ -16,15 +16,6 @@
 
 namespace Common::Log {
 
-// trims up to and including the last of ../, ..\, src/, src\ in a string
-constexpr const char* TrimSourcePath(std::string_view source) {
-    const auto rfind = [source](const std::string_view match) {
-        return source.rfind(match) == source.npos ? 0 : (source.rfind(match) + match.size());
-    };
-    auto idx = (std::max)({rfind("src/"), rfind("src\\"), rfind("../"), rfind("..\\")});
-    return source.data() + idx;
-}
-
 /// Logs a message to the global logger, using fmt
 void FmtLogMessageImpl(Class log_class, Level log_level, const char* filename,
                        unsigned int line_num, const char* function, fmt::string_view format,
@@ -42,7 +33,7 @@ void FmtLogMessage(Class log_class, Level log_level, const char* filename, unsig
 #ifdef _DEBUG
 #define LOG_TRACE(log_class, ...)                                                                  \
     Common::Log::FmtLogMessage(Common::Log::Class::log_class, Common::Log::Level::Trace,           \
-                               Common::Log::TrimSourcePath(__FILE__), __LINE__, __func__,          \
+                               __FILE__, __LINE__, __func__,          \
                                __VA_ARGS__)
 #else
 #define LOG_TRACE(log_class, fmt, ...) (void(0))
@@ -50,21 +41,21 @@ void FmtLogMessage(Class log_class, Level log_level, const char* filename, unsig
 
 #define LOG_DEBUG(log_class, ...)                                                                  \
     Common::Log::FmtLogMessage(Common::Log::Class::log_class, Common::Log::Level::Debug,           \
-                               Common::Log::TrimSourcePath(__FILE__), __LINE__, __func__,          \
+                               __FILE__, __LINE__, __func__,          \
                                __VA_ARGS__)
 #define LOG_INFO(log_class, ...)                                                                   \
     Common::Log::FmtLogMessage(Common::Log::Class::log_class, Common::Log::Level::Info,            \
-                               Common::Log::TrimSourcePath(__FILE__), __LINE__, __func__,          \
+                               __FILE__, __LINE__, __func__,          \
                                __VA_ARGS__)
 #define LOG_WARNING(log_class, ...)                                                                \
     Common::Log::FmtLogMessage(Common::Log::Class::log_class, Common::Log::Level::Warning,         \
-                               Common::Log::TrimSourcePath(__FILE__), __LINE__, __func__,          \
+                               __FILE__, __LINE__, __func__,          \
                                __VA_ARGS__)
 #define LOG_ERROR(log_class, ...)                                                                  \
     Common::Log::FmtLogMessage(Common::Log::Class::log_class, Common::Log::Level::Error,           \
-                               Common::Log::TrimSourcePath(__FILE__), __LINE__, __func__,          \
+                               __FILE__, __LINE__, __func__,          \
                                __VA_ARGS__)
 #define LOG_CRITICAL(log_class, ...)                                                               \
     Common::Log::FmtLogMessage(Common::Log::Class::log_class, Common::Log::Level::Critical,        \
-                               Common::Log::TrimSourcePath(__FILE__), __LINE__, __func__,          \
+                               __FILE__, __LINE__, __func__,          \
                                __VA_ARGS__)

src/core/hle/service/ssl/ssl_backend_openssl.cpp

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -286,7 +289,7 @@ Result CheckOpenSSLErrors() {
             msg.append(data);
         }
         Common::Log::FmtLogMessage(Common::Log::Class::Service_SSL, Common::Log::Level::Error,
-                                   Common::Log::TrimSourcePath(file), line, func, "OpenSSL: {}",
+                                   file, line, func, "OpenSSL: {}",
                                    msg);
     }
     return ResultInternalError;