[native] Remove the libc++ dependencies from the CoreCLR host's timing

src/native/clr/host/assembly-store.cc

@@ -791,7 +791,7 @@ auto AssemblyStore::open_assembly (std::string_view const& name, int64_t &size)
 	return assembly_data;
 }
 
-void AssemblyStore::configure_from_payload (const void *payload_start, const std::function<std::string()>& get_full_store_path) noexcept
+void AssemblyStore::configure_from_payload (const void *payload_start, const char *store_path) noexcept
 {
 	auto header = static_cast<const AssemblyStoreHeader*>(payload_start);
 
@@ -800,7 +800,7 @@ void AssemblyStore::configure_from_payload (const void *payload_start, const std
 			LOG_ASSEMBLY,
 			std::source_location::current (),
 			"Assembly store '%s' is not a valid .NET for Android assembly store file",
-			get_full_store_path ().c_str ()
+			optional_string (store_path)
 		);
 	}
 
@@ -809,7 +809,7 @@ void AssemblyStore::configure_from_payload (const void *payload_start, const std
 			LOG_ASSEMBLY,
 			std::source_location::current (),
 			"Assembly store '%s' uses format version %x, instead of the expected %x",
-			get_full_store_path ().c_str (),
+			optional_string (store_path),
 			header->version,
 			ASSEMBLY_STORE_FORMAT_VERSION
 		);
@@ -841,5 +841,5 @@ void AssemblyStore::configure_from_payload (const void *payload_start, const std
 		names_cursor += name_length;
 	}
 
-	log_debugf (LOG_ASSEMBLY, "Mapped assembly store %s; content ID 0x%" PRIx64, get_full_store_path ().c_str (), assembly_store_content_id);
+	log_debugf (LOG_ASSEMBLY, "Mapped assembly store %s; content ID 0x%" PRIx64, optional_string (store_path), assembly_store_content_id);
 }

src/native/clr/host/host.cc

@@ -197,7 +197,7 @@ void Host::map_assembly_store_via_dlopen (const char *store_path) noexcept
 	}
 
 	log_debugf (LOG_ASSEMBLY, "Assembly store payload via dynamic symbol: %p (%s)", payload, optional_string (store_path));
-	AssemblyStore::configure_from_payload (payload, [store_path]() -> std::string { return std::string { store_path }; });
+	AssemblyStore::configure_from_payload (payload, store_path);
 	found_assembly_store = true;
 }
 
@@ -316,7 +316,6 @@ void Host::Java_mono_android_Runtime_initInternal (
 	FastTiming::initialize ((Logger::log_timing_categories() & LogTimingCategories::FastBare) != LogTimingCategories::FastBare);
 
 	if (FastTiming::enabled ()) [[unlikely]] {
-		_timing = std::make_shared<Timing> ();
 		internal_timing.start_event (TimingEventKind::TotalRuntimeInit);
 	}
 

src/native/clr/host/internal-pinvokes-clr.cc

@@ -41,15 +41,11 @@ _monodroid_lookup_replacement_method_info (const char *jniSourceType, const char
 
 managed_timing_sequence* monodroid_timing_start (const char *message)
 {
-	// Technically a reference here is against the idea of shared pointers, but
-	// in this instance it's fine since we know we won't be storing the pointer
-	// and this way things are slightly faster.
-	std::shared_ptr<Timing> const &timing = Host::get_timing ();
-	if (!timing) {
+	if (!FastTiming::enabled ()) [[likely]] {
 		return nullptr;
 	}
 
-	managed_timing_sequence *ret = timing->get_available_sequence ();
+	managed_timing_sequence *ret = Host::get_timing ().get_available_sequence ();
 	if (message != nullptr) {
 		log_write (LOG_TIMING, LogLevel::Info, message);
 	}
@@ -64,12 +60,7 @@ void monodroid_timing_stop (managed_timing_sequence *sequence, const char *messa
 		return;
 	}
 
-	std::shared_ptr<Timing> const &timing = Host::get_timing ();
-	if (!timing) [[unlikely]] {
-		return;
-	}
-
 	sequence->end = FastTiming::get_time ();
 	Timing::info (sequence, message == nullptr ? DEFAULT_MESSAGE.data () : message);
-	timing->release_sequence (sequence);
+	Host::get_timing ().release_sequence (sequence);
 }

src/native/clr/include/host/assembly-store.hh

@@ -1,7 +1,6 @@
 #pragma once
 
 #include <cstdint>
-#include <functional>
 #include <limits>
 #include <pthread.h>
 #include <string>
@@ -19,9 +18,9 @@ namespace xamarin::android {
 		// Configure the store directly from an in-memory payload pointer (obtained via
 		// dlopen()+dlsym() of the `_assembly_store` dynamic symbol). The payload is mapped
 		// read-only and is never modified, so it (and every pointer derived from it) is `const`.
-		// `get_full_store_path` is invoked only to build diagnostics if the payload turns out
-		// to be invalid.
-		static void configure_from_payload (const void *payload_start, const std::function<std::string()>& get_full_store_path) noexcept;
+		// `store_path` is used only in diagnostic messages and may be `nullptr` - every use of it
+		// goes through `optional_string ()`.
+		static void configure_from_payload (const void *payload_start, const char *store_path) noexcept;
 
 	private:
 		static void set_assembly_data_and_size (uint8_t* source_assembly_data, uint32_t source_assembly_data_size, uint8_t*& dest_assembly_data, uint32_t& dest_assembly_data_size) noexcept;

src/native/clr/include/host/host.hh

@@ -23,7 +23,7 @@ namespace xamarin::android {
 		static void Java_mono_android_Runtime_registerNatives (JNIEnv *env, jclass nativeClass) noexcept;
 		static void propagate_uncaught_exception (JNIEnv *env, jobject javaThread, jthrowable javaException) noexcept;
 
-		static auto get_timing () -> std::shared_ptr<Timing>
+		static auto get_timing () noexcept -> Timing&
 		{
 			return _timing;
 		}
@@ -54,7 +54,10 @@ namespace xamarin::android {
 	private:
 		static inline void *clr_host = nullptr;
 		static inline unsigned int domain_id = 0;
-		static inline std::shared_ptr<Timing> _timing{};
+		// Constant-initialized and live for the whole lifetime of the process, so there is
+		// nothing to allocate or free. Only used when fast timing is enabled, which callers
+		// check with `FastTiming::enabled ()`.
+		static inline Timing _timing {};
 		static inline bool found_assembly_store = false;
 		static inline jnienv_register_jni_natives_fn jnienv_register_jni_natives = nullptr;
 		static inline jnienv_propagate_uncaught_exception_fn jnienv_propagate_uncaught_exception = nullptr;

src/native/common/include/runtime-base/mainthread-dso-loader.hh

@@ -5,7 +5,6 @@
 #include <unistd.h>
 
 #include <array>
-#include <chrono>
 #include <semaphore>
 #include <string_view>