mirror of
https://github.com/moparisthebest/fernflower
synced 2024-11-23 01:32:21 -05:00
89 lines
4.5 KiB
Plaintext
89 lines
4.5 KiB
Plaintext
1. About the decompiler
|
|
|
|
Fernflower is the first actually working analytical decompiler for Java and
|
|
probably for a high-level programming language in general. Naturally it is still
|
|
under development, please send your bug reports and improvement suggestions at
|
|
fernflower.decompiler@gmail.com
|
|
|
|
|
|
2. License
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
|
|
3. Running from the command line
|
|
|
|
java -jar fernflower.jar [-<option>=<value>]* [<source>]+ <destination>
|
|
|
|
* means 0 or more times
|
|
+ means 1 or more times
|
|
|
|
<source>: file or directory with files to be decompiled. Directories are recursively scanned. Allowed file extensions are class, zip and jar.
|
|
Sources prefixed with -e= mean "library" files that won't be decompiled, but taken into account when analysing relationships between
|
|
classes or methods. Especially renaming of identifiers (s. option 'ren') can benefit from information about external classes.
|
|
<destination>: destination directory
|
|
<option>,<value>: command line option with the corresponding value, see 4.
|
|
|
|
Examples:
|
|
|
|
java -jar fernflower.jar -hes=0 -hdc=0 c:\Temp\binary\ -e=c:\Java\rt.jar c:\Temp\source\
|
|
|
|
java -jar fernflower.jar -dgs=1 c:\Temp\binary\library.jar c:\Temp\binary\Boot.class c:\Temp\source\
|
|
|
|
|
|
4. Command line options
|
|
|
|
With the exception of mpm and urc the value of 1 means the option is activated, 0 - deactivated. Default
|
|
value, if any, is given between parentheses.
|
|
|
|
Typically, the following options will be changed by user, if any: hes, hdc, dgs, mpm, ren, urc
|
|
The rest of options can be left as they are: they are aimed at professional reverse engineers.
|
|
|
|
rbr (1): hide bridge methods
|
|
rsy (0): hide synthetic class members
|
|
din (1): decompile inner classes
|
|
dc4 (1): collapse 1.4 class references
|
|
das (1): decompile assertions
|
|
hes (1): hide empty super invocation
|
|
hdc (1): hide empty default constructor
|
|
dgs (0): decompile generic signatures
|
|
ner (1): assume return not throwing exceptions
|
|
den (1): decompile enumerations
|
|
rgn (1): remove getClass() invocation, when it is part of a qualified new statement
|
|
lit (0): output numeric literals "as-is"
|
|
asc (0): encode non-ASCII characters in string and character literals as Unicode escapes
|
|
bto (1): interpret int 1 as boolean true (workaround to a compiler bug)
|
|
nns (1): allow for not set synthetic attribute (workaround to a compiler bug)
|
|
uto (1): consider nameless types as java.lang.Object (workaround to a compiler architecture flaw)
|
|
udv (1): reconstruct variable names from debug information, if present
|
|
rer (1): remove empty exception ranges
|
|
fdi (1): de-inline finally structures
|
|
mpm (0): maximum allowed processing time per decompiled method, in seconds. 0 means no upper limit
|
|
ren (0): rename ambiguous (resp. obfuscated) classes and class elements
|
|
urc : full name of user-supplied class implementing IIdentifierRenamer. It is used to determine which class identifiers
|
|
should be renamed and provides new identifier names. For more information see section 5
|
|
inn (1): check for IntelliJ IDEA-specific @NotNull annotation and remove inserted code if found
|
|
lac (0): decompile lambda expressions to anonymous classes
|
|
nls (0): define new line character to be used for output. 0 - '\r\n' (Windows), 1 - '\n' (Linux), default is OS-dependent
|
|
ind : indentation string (default is " " (3 spaces))
|
|
|
|
The default logging level is INFO. This value can be overwritten by setting the option 'log' as follows:
|
|
log (INFO): possible values TRACE, INFO, WARN, ERROR
|
|
|
|
|
|
5. Renaming identifiers
|
|
|
|
Some obfuscators give classes and their member elements short, meaningless and above all ambiguous names. Recompiling of such
|
|
code leads to a great number of conflicts. Therefore it is advisable to let the decompiler rename elements in its turn,
|
|
ensuring uniqueness of each identifier.
|
|
|
|
Option 'ren' (i.e. -ren=1) activates renaming functionality. Default renaming strategy goes as follows:
|
|
- rename an element if its name is a reserved word or is shorter than 3 characters
|
|
- new names are built according to a simple pattern: (class|method|field)_<consecutive unique number>
|
|
You can overwrite this rules by providing your own implementation of the 4 key methods invoked by the decompiler while renaming. Simply
|
|
pass a class that implements org.jetbrains.java.decompiler.main.extern.IIdentifierRenamer in the option 'urc'
|
|
(e.g. -urc=com.mypackage.MyRenamer) to Fernflower. The class must be available on the application classpath.
|
|
|
|
The meaning of each method should be clear from naming: toBeRenamed determine whether the element will be renamed, while the other three
|
|
provide new names for classes, methods and fields respectively.
|