[llvmonly] Throw an ExecutionEngine exception with a helpful message when we try to execute a method which failed AOT compilation.

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Author: vargaz

src/mono/mono/metadata/jit-icall-reg.h

@@ -139,7 +139,7 @@ MONO_JIT_ICALL (mini_llvmonly_resolve_generic_virtual_iface_call) \
 MONO_JIT_ICALL (mini_llvmonly_resolve_iface_call_gsharedvt) \
 MONO_JIT_ICALL (mini_llvmonly_resolve_vcall_gsharedvt) \
 MONO_JIT_ICALL (mini_llvmonly_throw_nullref_exception) \
-MONO_JIT_ICALL (mini_llvmonly_throw_missing_method_exception) \
+MONO_JIT_ICALL (mini_llvmonly_throw_aot_failed_exception) \
 MONO_JIT_ICALL (mono_amd64_resume_unwind)	\
 MONO_JIT_ICALL (mono_amd64_start_gsharedvt_call)	\
 MONO_JIT_ICALL (mono_amd64_throw_corlib_exception)	\

src/mono/mono/mini/llvmonly-runtime.c

@@ -809,14 +809,11 @@ mini_llvmonly_throw_nullref_exception (void)
 	mono_llvm_throw_corlib_exception (ex_token_index);
 }
 
-static GENERATE_GET_CLASS_WITH_CACHE (missing_method, "System", "MissingMethodException")
-
 void
-mini_llvmonly_throw_missing_method_exception (void)
+mini_llvmonly_throw_aot_failed_exception (const char *name)
 {
-	MonoClass *klass = mono_class_get_missing_method_class ();
-
-	guint32 ex_token_index = m_class_get_type_token (klass) - MONO_TOKEN_TYPE_DEF;
-
-	mono_llvm_throw_corlib_exception (ex_token_index);
+	char *msg = g_strdup_printf ("AOT Compilation failed for method '%s'.", name);
+	MonoException *ex = mono_get_exception_execution_engine (msg);
+	g_free (msg);
+	mono_llvm_throw_exception ((MonoObject*)ex);
 }

src/mono/mono/mini/llvmonly-runtime.h

@@ -33,6 +33,6 @@ G_EXTERN_C void mini_llvm_init_method          (MonoAotFileInfo *info, gpointer
 
 G_EXTERN_C void mini_llvmonly_throw_nullref_exception (void);
 
-G_EXTERN_C void mini_llvmonly_throw_missing_method_exception (void);
+G_EXTERN_C void mini_llvmonly_throw_aot_failed_exception (const char *name);
 
 #endif

src/mono/mono/mini/mini-llvm.c

@@ -9542,10 +9542,22 @@ emit_method_inner (EmitContext *ctx)
 		ctx->builder = create_builder (ctx);
 		LLVMPositionBuilderAtEnd (ctx->builder, ctx->inited_bb);
 
+		char *name = mono_method_get_full_name (cfg->method);
+		int len = strlen (name);
+
+		LLVMTypeRef type = LLVMArrayType (LLVMInt8Type (), len + 1);
+		LLVMValueRef name_var = LLVMAddGlobal (ctx->lmodule, type, "missing_method_name");
+		LLVMSetVisibility (name_var, LLVMHiddenVisibility);
+		LLVMSetLinkage (name_var, LLVMInternalLinkage);
+		LLVMSetInitializer (name_var, mono_llvm_create_constant_data_array ((guint8*)name, len + 1));
+		mono_llvm_set_is_constant (name_var);
+		g_free (name);
+
 		if (!sig)
-			sig = LLVMFunctionType0 (LLVMVoidType (), FALSE);
-		LLVMValueRef callee = get_callee (ctx, sig, MONO_PATCH_INFO_JIT_ICALL_ADDR, GUINT_TO_POINTER (MONO_JIT_ICALL_mini_llvmonly_throw_missing_method_exception));
-		LLVMBuildCall (ctx->builder, callee, NULL, 0, "");
+			sig = LLVMFunctionType1 (LLVMVoidType (), ctx->module->ptr_type, FALSE);
+		LLVMValueRef callee = get_callee (ctx, sig, MONO_PATCH_INFO_JIT_ICALL_ADDR, GUINT_TO_POINTER (MONO_JIT_ICALL_mini_llvmonly_throw_aot_failed_exception));
+		LLVMValueRef args [] = { convert (ctx, name_var, ctx->module->ptr_type) };
+		LLVMBuildCall (ctx->builder, callee, args, 1, "");
 		LLVMBuildUnreachable (ctx->builder);
 	}
 

src/mono/mono/mini/mini-runtime.c

@@ -4672,7 +4672,7 @@ register_icalls (void)
 	register_icall (mini_llvmonly_init_delegate, mono_icall_sig_void_object, TRUE);
 	register_icall (mini_llvmonly_init_delegate_virtual, mono_icall_sig_void_object_object_ptr, TRUE);
 	register_icall (mini_llvmonly_throw_nullref_exception, mono_icall_sig_void, TRUE);
-	register_icall (mini_llvmonly_throw_missing_method_exception, mono_icall_sig_void, TRUE);
+	register_icall (mini_llvmonly_throw_aot_failed_exception, mono_icall_sig_void_ptr, TRUE);
 
 	register_icall (mono_get_assembly_object, mono_icall_sig_object_ptr, TRUE);
 	register_icall (mono_get_method_object, mono_icall_sig_object_ptr, TRUE);