YourWishes/jerryscript
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Cleanup code around JERRY_UNREACHABLEs (#2342)

Browse Source 
`JERRY_UNREACHABLE`s often signal code structure that could be
improved: they can usually either be rewritten to `JERRY_ASSERT`s
or eliminated by restructuring loops, `if`s or `#if`s. Roughly,
the only valid occurences are in default cases of `switch`es. And
even they can often be merged into non-default cases.

Moreover, it is dangerous to write meaningful code after
`JERRY_UNREACHABLE` because it pretends as if there was a way to
recover from an impossible situation.

This patch rewrites/eliminates `JERRY_UNREACHABLE`s where possible
and removes misleading code from after them.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu
This commit is contained in:
Akos Kiss
2018-05-25 07:27:30 +02:00
committed by GitHub
parent acb3e71436
commit 4779451284
24 changed files with 168 additions and 256 deletions
Download Patch File Download Diff File Expand all files Collapse all files
jerry-core/vm/vm-stack.c
+3 -6
View File
@@ -65,8 +65,10 @@ vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
vm_stack_top_p -= PARSER_TRY_CONTEXT_STACK_ALLOCATION;
break;
}
case VM_CONTEXT_FOR_IN:
default:
{
JERRY_ASSERT (VM_GET_CONTEXT_TYPE (vm_stack_top_p[-1]) == VM_CONTEXT_FOR_IN);
ecma_collection_chunk_t *chunk_p;
chunk_p = ECMA_GET_INTERNAL_VALUE_ANY_POINTER (ecma_collection_chunk_t, vm_stack_top_p[-2]);
uint32_t index = vm_stack_top_p[-3];
@@ -96,11 +98,6 @@ vm_stack_context_abort (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
vm_stack_top_p -= PARSER_FOR_IN_CONTEXT_STACK_ALLOCATION;
break;
}
default:
{
JERRY_UNREACHABLE ();
break;
}
}
return vm_stack_top_p;
jerry-core/vm/vm.c
+29 -35
View File
@@ -298,52 +298,26 @@ static ecma_value_t
vm_construct_literal_object (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
ecma_value_t lit_value) /**< literal */
{
#ifdef JERRY_ENABLE_SNAPSHOT_EXEC
ecma_compiled_code_t *bytecode_p;
#ifdef JERRY_ENABLE_SNAPSHOT_EXEC
if (JERRY_LIKELY (!(frame_ctx_p->bytecode_header_p->status_flags & CBC_CODE_FLAGS_STATIC_FUNCTION)))
{
#endif /* JERRY_ENABLE_SNAPSHOT_EXEC */
bytecode_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_compiled_code_t,
lit_value);
#ifdef JERRY_ENABLE_SNAPSHOT_EXEC
}
else
{
uint8_t *byte_p = ((uint8_t *) frame_ctx_p->bytecode_header_p) + lit_value;
bytecode_p = (ecma_compiled_code_t *) byte_p;
}
#else /* !JERRY_ENABLE_SNAPSHOT_EXEC */
ecma_compiled_code_t *bytecode_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_compiled_code_t,
lit_value);
#endif /* JERRY_ENABLE_SNAPSHOT_EXEC */
bool is_function = ((bytecode_p->status_flags & CBC_CODE_FLAGS_FUNCTION) != 0);
if (is_function)
{
ecma_object_t *func_obj_p;
#ifndef CONFIG_DISABLE_ES2015_ARROW_FUNCTION
if (!(bytecode_p->status_flags & CBC_CODE_FLAGS_ARROW_FUNCTION))
{
func_obj_p = ecma_op_create_function_object (frame_ctx_p->lex_env_p,
bytecode_p);
}
else
{
func_obj_p = ecma_op_create_arrow_function_object (frame_ctx_p->lex_env_p,
bytecode_p,
frame_ctx_p->this_binding);
}
#else /* CONFIG_DISABLE_ES2015_ARROW_FUNCTION */
func_obj_p = ecma_op_create_function_object (frame_ctx_p->lex_env_p,
bytecode_p);
#endif /* !CONFIG_DISABLE_ES2015_ARROW_FUNCTION */
return ecma_make_object_value (func_obj_p);
}
else
{
#ifndef CONFIG_DISABLE_REGEXP_BUILTIN
if (!(bytecode_p->status_flags & CBC_CODE_FLAGS_FUNCTION))
{
ecma_value_t ret_value;
ret_value = ecma_op_create_regexp_object_from_bytecode ((re_compiled_code_t *) bytecode_p);
@@ -354,10 +328,30 @@ vm_construct_literal_object (vm_frame_ctx_t *frame_ctx_p, /**< frame context */
}
return ret_value;
#else /* CONFIG_DISABLE_REGEXP_BUILTIN */
JERRY_UNREACHABLE (); /* Regular Expressions are not supported in the selected profile! */
#endif /* !CONFIG_DISABLE_REGEXP_BUILTIN */
}
#endif /* !CONFIG_DISABLE_REGEXP_BUILTIN */
JERRY_ASSERT (bytecode_p->status_flags & CBC_CODE_FLAGS_FUNCTION);
ecma_object_t *func_obj_p;
#ifndef CONFIG_DISABLE_ES2015_ARROW_FUNCTION
if (!(bytecode_p->status_flags & CBC_CODE_FLAGS_ARROW_FUNCTION))
{
#endif /* !CONFIG_DISABLE_ES2015_ARROW_FUNCTION */
func_obj_p = ecma_op_create_function_object (frame_ctx_p->lex_env_p,
bytecode_p);
#ifndef CONFIG_DISABLE_ES2015_ARROW_FUNCTION
}
else
{
func_obj_p = ecma_op_create_arrow_function_object (frame_ctx_p->lex_env_p,
bytecode_p,
frame_ctx_p->this_binding);
}
#endif /* !CONFIG_DISABLE_ES2015_ARROW_FUNCTION */
return ecma_make_object_value (func_obj_p);
} /* vm_construct_literal_object */
/**
@@ -853,6 +847,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
default:
{
JERRY_ASSERT (operands == VM_OC_GET_THIS_LITERAL);
right_value = left_value;
left_value = ecma_copy_value (frame_ctx_p->this_binding);
break;
@@ -2681,7 +2676,6 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
default:
{
JERRY_UNREACHABLE ();
continue;
}
}