Disassembler

Overview

Disassembler is a utility in the ArkTS toolchain designed to convert Ark bytecode files (*.abc) into human-readable assembly instructions. It is particularly useful when you want to analyze or debug issues related to Ark bytecode files.

Disassembler is released with the DevEco Studio SDK. For instance, on Windows, the tool can be found at: DevEco Studio/sdk/default/openharmony/toolchains/ark_disasm.exe.

Command-Line Instructions

To use Disassembler, run the following command:

ark_disasm.exe [options] input_file output_file

Parameters

Parameter	Optional	Description
[options]	Yes	Command options. For details, see Description of options below.
input_file	No	Path of the Ark bytecode file to be disassembled.
output_file	No	Path where the disassembled file will be saved.

Description of options

Option	Mandatory	Argument Carried	Description
--debug	No	No	Enables the function of outputting debugging information. By default, debugging information is output to the screen.
--debug-file	No	Yes	Specifies the output file of debugging information if --debug is enabled.
--help	No	No	Displays help information.
--skip-string-literals	No	No	Skips disassembly of string literals.
--quiet	No	No	Enables all options prefixed with --skip-.
--verbose	No	No	Enables the output of additional information (byte position, ARK bytecode format, and operation code).
--version	No	No	Displays the version of the Ark bytecode file and the minimum supported version.

Usage Example

Assume that the Ark bytecode file test.abc exists, with the following source code:

let i = 99;
function show(){return i;}
show();

Run the following command to generate a disassembled file named test.txt, which contains information such as the operation code and format:

ark_disasm.exe test.abc test.txt

Run the following command to view the content of the disassembled file:

cat test.txt

The file content is as follows:

# source binary: test.abc                                                    // Disassembled Ark bytecode file.

.language ECMAScript

# ====================
# LITERALS                                                                   // Literal data.

0 0x203 { 0 [
    MODULE_REQUEST_ARRAY: {
    };
]}

# ====================
# RECORDS                                                                    // Module definition data.

.record _ESConcurrentModuleRequestsAnnotation {                              // Data prefixed with _ is fixed module data.
}

.record test {                                                               // One JS file corresponds to one module. It contains the module information, for example, location in the ARK bytecode file and whether it is CommonJS.
    u8 isCommonjs = 0x0
    u32 moduleRecordIdx = 0x203
    ......
}

# ====================
# METHODS                                                                    // Method definition data.

L_ESSlotNumberAnnotation:
    u32 slotNumberIdx { 0x0 }
.function any test.#*#show(any a0, any a1, any a2) <static> {                // The show method in the source code. It belongs to the test module.
    ldlexvar 0x0, 0x0
    ......
}

L_ESSlotNumberAnnotation:
    u32 slotNumberIdx { 0x3 }
.function any test.func_main_0(any a0, any a1, any a2) <static> {            // The method is automatically generated. The entire JS file can be regarded as a method named func_main_0.
    newlexenv 0x1
    ......
}

# ====================
# STRING                                                                     // Symbol table information

[offset:0x88, name_value:i]

Use the --verbose parameter to print more details such as the offset.

ark_disasm.exe --verbose test.abc test.txt

Here are some examples of the output with --verbose:

.record _ESSlotNumberAnnotation { # offset: 0x00cd, size: 0x0026 (38)                                  // This prints the location and size of the module within the ARK bytecode file.
}

.record test { # offset: 0x00f3, size: 0x0098 (152)                                                    // This prints the location of the module within the ARK bytecode file.
    u32 moduleRecordIdx = 0x203 # offset: 0x0144                                                   // This prints the location of the module information.
}
......
.function any test.#*#show(any a0, any a1, any a2) <static> { # offset: 0x0153, code offset: 0x0245    // This prints the location of the method information and the location of the instruction in the method.
#   CODE:
    ldlexvar 0x0, 0x0 # offset: 0x0249, [IMM4_IMM4].........[0x3c 0x00]                            // This prints the location of each command.
    ......
}