[mono] More domain cleanups (#50479)

* [mono] More domain cleanups.

* [mono] Move the storage of the loaded assemblies list to assembly-load-context.c.

Add a mono_alc_get_all_loaded_assemblies () helper function to return a
array of all the loaded assemblies. Use this instead of accessing
domain->loaded_assemblies directly.

* [mono] Move externally called domain related API functions to external-only.c.

* [mono] Simplify the domain creation code since there is only one domain.

* Remove domain argument from mono_domain_assembly_open_internal ().

* [mono] Make mono_domain_foreach () external only.

* Fix the build.

* [mono] Remove more unused 'domain' arguments.

Move functions from appdomain.c to more assembly-load-context.c/
extern-only.c.

src/mono/mono/metadata/appdomain.h

@@ -73,13 +73,13 @@ mono_domain_set_config (MonoDomain *domain, const char *base_dir, const char *co
 MONO_API MonoDomain *
 mono_domain_get            (void);
 
-MONO_API MonoDomain *
+MONO_API MONO_RT_EXTERNAL_ONLY MonoDomain *
 mono_domain_get_by_id      (int32_t domainid);
 
-MONO_API int32_t
+MONO_API MONO_RT_EXTERNAL_ONLY int32_t
 mono_domain_get_id         (MonoDomain *domain);
 
-MONO_API const char *
+MONO_API MONO_RT_EXTERNAL_ONLY const char *
 mono_domain_get_friendly_name (MonoDomain *domain);
 
 MONO_API MONO_RT_EXTERNAL_ONLY mono_bool
@@ -91,16 +91,16 @@ mono_domain_set_internal   (MonoDomain *domain);
 MONO_API MONO_RT_EXTERNAL_ONLY void
 mono_domain_unload (MonoDomain *domain);
 
-MONO_API void
+MONO_API MONO_RT_EXTERNAL_ONLY void
 mono_domain_try_unload (MonoDomain *domain, MonoObject **exc);
 
-MONO_API mono_bool
+MONO_API MONO_RT_EXTERNAL_ONLY mono_bool
 mono_domain_is_unloading   (MonoDomain *domain);
 
 MONO_API MONO_RT_EXTERNAL_ONLY MonoDomain *
 mono_domain_from_appdomain (MonoAppDomain *appdomain);
 
-MONO_API void
+MONO_API MONO_RT_EXTERNAL_ONLY void
 mono_domain_foreach        (MonoDomainFunc func, void* user_data);
 
 MONO_API MONO_RT_EXTERNAL_ONLY MonoAssembly *
@@ -112,7 +112,7 @@ mono_domain_ensure_entry_assembly (MonoDomain *domain, MonoAssembly *assembly);
 MONO_API MONO_RT_EXTERNAL_ONLY mono_bool
 mono_domain_finalize       (MonoDomain *domain, uint32_t timeout);
 
-MONO_API void
+MONO_API MONO_RT_EXTERNAL_ONLY void
 mono_domain_free           (MonoDomain *domain, mono_bool force);
 
 MONO_API mono_bool
@@ -130,13 +130,13 @@ mono_context_init 				   (MonoDomain *domain);
 MONO_API MONO_RT_EXTERNAL_ONLY void
 mono_context_set				   (MonoAppContext *new_context);
 
-MONO_API MonoAppContext * 
+MONO_API MONO_RT_EXTERNAL_ONLY MonoAppContext *
 mono_context_get				   (void);
 
-MONO_API int32_t
+MONO_API MONO_RT_EXTERNAL_ONLY int32_t
 mono_context_get_id         (MonoAppContext *context);
 
-MONO_API int32_t
+MONO_API MONO_RT_EXTERNAL_ONLY int32_t
 mono_context_get_domain_id  (MonoAppContext *context);
 
 MONO_API MonoJitInfo *

src/mono/mono/metadata/assembly-load-context.c

@@ -2,20 +2,25 @@
 #include "mono/utils/mono-compiler.h"
 
 #include "mono/metadata/assembly.h"
+#include "mono/metadata/assembly-internals.h"
 #include "mono/metadata/domain-internals.h"
 #include "mono/metadata/exception-internals.h"
 #include "mono/metadata/icall-decl.h"
 #include "mono/metadata/loader-internals.h"
 #include "mono/metadata/loaded-images-internals.h"
 #include "mono/metadata/mono-private-unstable.h"
+#include "mono/metadata/mono-debug.h"
 #include "mono/utils/mono-error-internals.h"
 #include "mono/utils/mono-logger-internals.h"
 
 GENERATE_GET_CLASS_WITH_CACHE (assembly_load_context, "System.Runtime.Loader", "AssemblyLoadContext");
+static GENERATE_GET_CLASS_WITH_CACHE (assembly, "System.Reflection", "Assembly");
 
 static GSList *alcs;
 static MonoAssemblyLoadContext *default_alc;
 static MonoCoopMutex alc_list_lock; /* Used when accessing 'alcs' */
+/* Protected by alc_list_lock */
+static GSList *loaded_assemblies;
 
 static inline void
 alcs_lock (void)
@@ -92,17 +97,18 @@ mono_alc_cleanup_assemblies (MonoAssemblyLoadContext *alc)
 	// The minimum refcount on assemblies is 2: one for the domain and one for the ALC. 
 	// The domain refcount might be less than optimal on netcore, but its removal is too likely to cause issues for now.
 	GSList *tmp;
-	MonoDomain *domain = mono_get_root_domain ();
 
-	// Remove the assemblies from domain_assemblies
-	mono_domain_assemblies_lock (domain);
+	// Remove the assemblies from loaded_assemblies
 	for (tmp = alc->loaded_assemblies; tmp; tmp = tmp->next) {
 		MonoAssembly *assembly = (MonoAssembly *)tmp->data;
-		domain->domain_assemblies = g_slist_remove (domain->domain_assemblies, assembly);
+
+		alcs_lock ();
+		loaded_assemblies = g_slist_remove (loaded_assemblies, assembly);
+		alcs_unlock ();
+
 		mono_assembly_decref (assembly);
-		mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_ASSEMBLY, "Unloading ALC [%p], removing assembly %s[%p] from domain_assemblies, ref_count=%d\n", alc, assembly->aname.name, assembly, assembly->ref_count);
+		mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_ASSEMBLY, "Unloading ALC [%p], removing assembly %s[%p] from loaded_assemblies, ref_count=%d\n", alc, assembly->aname.name, assembly, assembly->ref_count);
 	}
-	mono_domain_assemblies_unlock (domain);
 
 	// Release the GC roots
 	for (tmp = alc->loaded_assemblies; tmp; tmp = tmp->next) {
@@ -262,6 +268,135 @@ ves_icall_System_Runtime_Loader_AssemblyLoadContext_GetLoadContextForAssembly (M
 	return (gpointer)alc->gchandle;
 }
 
+static gboolean
+add_assembly_to_array (MonoArrayHandle dest, int dest_idx, MonoAssembly* assm, MonoError *error)
+{
+	HANDLE_FUNCTION_ENTER ();
+	error_init (error);
+	MonoReflectionAssemblyHandle assm_obj = mono_assembly_get_object_handle (assm, error);
+	goto_if_nok (error, leave);
+	MONO_HANDLE_ARRAY_SETREF (dest, dest_idx, assm_obj);
+leave:
+	HANDLE_FUNCTION_RETURN_VAL (is_ok (error));
+}
+
+MonoArrayHandle
+ves_icall_System_Runtime_Loader_AssemblyLoadContext_InternalGetLoadedAssemblies (MonoError *error)
+{
+	GPtrArray *assemblies = mono_alc_get_all_loaded_assemblies ();
+
+	MonoArrayHandle res = mono_array_new_handle (mono_class_get_assembly_class (), assemblies->len, error);
+	goto_if_nok (error, leave);
+	for (int i = 0; i < assemblies->len; ++i) {
+		if (!add_assembly_to_array (res, i, (MonoAssembly *)g_ptr_array_index (assemblies, i), error))
+			goto leave;
+	}
+
+leave:
+	g_ptr_array_free (assemblies, TRUE);
+	return res;
+}
+
+static
+MonoAssembly *
+mono_alc_load_file (MonoAssemblyLoadContext *alc, MonoStringHandle fname, MonoAssembly *executing_assembly, MonoAssemblyContextKind asmctx, MonoError *error)
+{
+	MonoAssembly *ass = NULL;
+	HANDLE_FUNCTION_ENTER ();
+	char *filename = NULL;
+	if (MONO_HANDLE_IS_NULL (fname)) {
+		mono_error_set_argument_null (error, "assemblyFile", "");
+		goto leave;
+	}
+
+	filename = mono_string_handle_to_utf8 (fname, error);
+	goto_if_nok (error, leave);
+
+	if (!g_path_is_absolute (filename)) {
+		mono_error_set_argument (error, "assemblyFile", "Absolute path information is required.");
+		goto leave;
+	}
+
+	MonoImageOpenStatus status;
+	MonoAssemblyOpenRequest req;
+	mono_assembly_request_prepare_open (&req, asmctx, alc);
+	req.requesting_assembly = executing_assembly;
+	ass = mono_assembly_request_open (filename, &req, &status);
+	if (!ass) {
+		if (status == MONO_IMAGE_IMAGE_INVALID)
+			mono_error_set_bad_image_by_name (error, filename, "Invalid Image: %s", filename);
+		else
+			mono_error_set_simple_file_not_found (error, filename);
+	}
+
+leave:
+	g_free (filename);
+	HANDLE_FUNCTION_RETURN_VAL (ass);
+}
+
+MonoReflectionAssemblyHandle
+ves_icall_System_Runtime_Loader_AssemblyLoadContext_InternalLoadFile (gpointer alc_ptr, MonoStringHandle fname, MonoStackCrawlMark *stack_mark, MonoError *error)
+{
+	MonoReflectionAssemblyHandle result = MONO_HANDLE_CAST (MonoReflectionAssembly, NULL_HANDLE);
+	MonoAssemblyLoadContext *alc = (MonoAssemblyLoadContext *)alc_ptr;
+
+	MonoAssembly *executing_assembly;
+	executing_assembly = mono_runtime_get_caller_from_stack_mark (stack_mark);
+	MonoAssembly *ass = mono_alc_load_file (alc, fname, executing_assembly, mono_alc_is_default (alc) ? MONO_ASMCTX_LOADFROM : MONO_ASMCTX_INDIVIDUAL, error);
+	goto_if_nok (error, leave);
+
+	result = mono_assembly_get_object_handle (ass, error);
+
+leave:
+	return result;
+}
+
+static MonoAssembly*
+mono_alc_load_raw_bytes (MonoAssemblyLoadContext *alc, guint8 *assembly_data, guint32 raw_assembly_len, guint8 *raw_symbol_data, guint32 raw_symbol_len, MonoError *error)
+{
+	MonoAssembly *ass = NULL;
+	MonoImageOpenStatus status;
+	MonoImage *image = mono_image_open_from_data_internal (alc, (char*)assembly_data, raw_assembly_len, TRUE, NULL, FALSE, NULL, NULL);
+
+	if (!image) {
+		mono_error_set_bad_image_by_name (error, "In memory assembly", "0x%p", assembly_data);
+		return ass;
+	}
+
+	if (raw_symbol_data)
+		mono_debug_open_image_from_memory (image, raw_symbol_data, raw_symbol_len);
+
+	MonoAssemblyLoadRequest req;
+	mono_assembly_request_prepare_load (&req, MONO_ASMCTX_INDIVIDUAL, alc);
+	ass = mono_assembly_request_load_from (image, "", &req, &status);
+
+	if (!ass) {
+		mono_image_close (image);
+		mono_error_set_bad_image_by_name (error, "In Memory assembly", "0x%p", assembly_data);
+		return ass;
+	}
+
+	/* Clear the reference added by mono_image_open_from_data_internal above */
+	mono_image_close (image);
+
+	return ass;
+}
+
+MonoReflectionAssemblyHandle
+ves_icall_System_Runtime_Loader_AssemblyLoadContext_InternalLoadFromStream (gpointer native_alc, gpointer raw_assembly_ptr, gint32 raw_assembly_len, gpointer raw_symbols_ptr, gint32 raw_symbols_len, MonoError *error)
+{
+	MonoAssemblyLoadContext *alc = (MonoAssemblyLoadContext *)native_alc;
+	MonoReflectionAssemblyHandle result = MONO_HANDLE_CAST (MonoReflectionAssembly, NULL_HANDLE);
+	MonoAssembly *assm = NULL;
+	assm = mono_alc_load_raw_bytes (alc, (guint8 *)raw_assembly_ptr, raw_assembly_len, (guint8 *)raw_symbols_ptr, raw_symbols_len, error);
+	goto_if_nok (error, leave);
+
+	result = mono_assembly_get_object_handle (assm, error);
+
+leave:
+	return result;
+}
+
 gboolean
 mono_alc_is_default (MonoAssemblyLoadContext *alc)
 {
@@ -420,3 +555,77 @@ mono_alc_invoke_resolve_using_resolve_satellite_nofail (MonoAssemblyLoadContext
 
 	return result;
 }
+
+void
+mono_alc_add_assembly (MonoAssemblyLoadContext *alc, MonoAssembly *ass)
+{
+	GSList *tmp;
+
+	g_assert (ass);
+
+	if (!ass->aname.name)
+		return;
+
+	mono_alc_assemblies_lock (alc);
+	for (tmp = alc->loaded_assemblies; tmp; tmp = tmp->next) {
+		if (tmp->data == ass) {
+			mono_alc_assemblies_unlock (alc);
+			return;
+		}
+	}
+
+	mono_assembly_addref (ass);
+	// Prepending here will break the test suite with frequent InvalidCastExceptions, so we have to append
+	alc->loaded_assemblies = g_slist_append (alc->loaded_assemblies, ass);
+	mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_ASSEMBLY, "Assembly %s[%p] added to ALC (%p), ref_count=%d", ass->aname.name, ass, (gpointer)alc, ass->ref_count);
+	mono_alc_assemblies_unlock (alc);
+
+	alcs_lock ();
+	loaded_assemblies = g_slist_append (loaded_assemblies, ass);
+	alcs_unlock ();
+}
+
+MonoAssembly*
+mono_alc_find_assembly (MonoAssemblyLoadContext *alc, MonoAssemblyName *aname)
+{
+	GSList *tmp;
+	MonoAssembly *ass;
+
+	const MonoAssemblyNameEqFlags eq_flags = MONO_ANAME_EQ_IGNORE_PUBKEY | MONO_ANAME_EQ_IGNORE_VERSION | MONO_ANAME_EQ_IGNORE_CASE;
+
+	mono_alc_assemblies_lock (alc);
+	for (tmp = alc->loaded_assemblies; tmp; tmp = tmp->next) {
+		ass = (MonoAssembly *)tmp->data;
+		g_assert (ass != NULL);
+		// FIXME: Can dynamic assemblies match here for netcore?
+		if (assembly_is_dynamic (ass) || !mono_assembly_names_equal_flags (aname, &ass->aname, eq_flags))
+			continue;
+
+		mono_alc_assemblies_unlock (alc);
+		return ass;
+	}
+	mono_alc_assemblies_unlock (alc);
+	return NULL;
+}
+
+/*
+ * mono_alc_get_all_loaded_assemblies:
+ *
+ *   Return a list of loaded assemblies in all appdomains.
+ */
+GPtrArray*
+mono_alc_get_all_loaded_assemblies (void)
+{
+	GSList *tmp;
+	GPtrArray *assemblies;
+	MonoAssembly *ass;
+
+	assemblies = g_ptr_array_new ();
+	alcs_lock ();
+	for (tmp = loaded_assemblies; tmp; tmp = tmp->next) {
+		ass = (MonoAssembly *)tmp->data;
+		g_ptr_array_add (assemblies, ass);
+	}
+	alcs_unlock ();
+	return assemblies;
+}

src/mono/mono/metadata/class-internals.h

@@ -1536,6 +1536,13 @@ m_field_get_offset (MonoClassField *field)
  * the lifetime of the image/class/method.
  */
 
+static inline MonoMemoryManager*
+mono_mem_manager_get_ambient (void)
+{
+	// FIXME: All callers should get a MemoryManager from their callers or context
+	return (MonoMemoryManager *)mono_alc_get_default ()->memory_manager;
+}
+
 static inline MonoMemoryManager*
 m_image_get_mem_manager (MonoImage *image)
 {
@@ -1582,7 +1589,7 @@ static inline MonoMemoryManager*
 m_method_get_mem_manager (MonoMethod *method)
 {
 	// FIXME:
-	return mono_domain_memory_manager (mono_get_root_domain ());
+	return (MonoMemoryManager *)mono_alc_get_default ()->memory_manager;
 }
 
 static inline void *