The new transformer uses a different approach to the old one. It starts
exploring the call graph from the entry points, recursively analysing
method calls. Methods are only re-analysed if their possible argument
values change, with the Unknown value being used if we can't identify a
single integer constant at a call site. This prevents us from recursing
infinitely if the client code does.
While this first pass does simplify branches in order to ignore dummy
method calls that are never evaluated at runtime, it operates on a copy
of the method (as we initially ignore more calls while the argument
value sets are smaller, ignoring fewer calls as they build up).
A separate second pass simplifies branches on the original method and
inlines singleton constants, paving the way for the UnusedArgTransformer
to actually remove the newly unused arguments.
This new approach has several benefits:
- It is much faster than the old approach, as we only re-analyse methods
as required by argument value changes, rather than re-analysing every
method during every pass.
- It doesn't require special cases for dealing with mutually recursive
dummy calls. The old approach hard-coded special cases for mutually
recursive calls involving groups of 1 and 2 methods. The code for this
wasn't clean. Furthermore, while it was just about good enough for the
HD client, the SD client contains a mutually recursive group of 3
methods. The new approach is capable of dealing with mutually
recursive groups of any size.
Finally, the new transformer has a much cleaner implementation.
Signed-off-by: Graham <gpe@openrs2.dev>
IDEA's test runner doesn't work very well with multi-module projects,
particularly where there are different versions of jars in the
classpath.
Signed-off-by: Graham <gpe@openrs2.dev>
We only need to check for the ACC_FINAL flag once at the start of
transformCode(), given the insn.owner == clazz.name condition. This
change also removes the redundant getNode() call - we already have a
reference to the ClassNode.
Signed-off-by: Graham <gpe@openrs2.dev>
As I'm splitting it up into smaller modules (e.g. compress and crypto) I
think util is a more appropriate name for the remainder.
Signed-off-by: Graham <gpe@openrs2.dev>
This is useful for checking the CRC-32 checksum of files used by the
loader. It outputs the checksum in signed decimal format, which is the
format used in the file name suffixes in the loader (e.g.
unpackclass_-1911426584.pack).
Signed-off-by: Graham <gpe@openrs2.dev>
These are useful for manipulating the files used by the loader, some of
which are compressed with DEFLATE or headerless gzip.
Signed-off-by: Graham <gpe@openrs2.dev>
The non-HD client appears to have been compiled with javac 1.1 or 1.2,
which compiles synchronized blocks differently to modern versions of
Java. For example, it uses a single try/catch block (modern versions use
two, the latter of which is recursive), subroutines (modern versions do
not) and the range of the try block is narrower.
Fernflower doesn't understand this old style of bytecode, and produces
empty synchronized blocks that do not cover the correct range.
The MONITORENTER sequence is also slightly different: it uses
ASTORE ALOAD MONITORENTER after pushing the monitor variable, rather
than DUP ASTORE MONITORENTER. This doesn't break Fernflower, but does
make it introduce a pointless assignment to a variable only used in the
synchronized() statement, rather than inlining the expression.
This commit introduces a transformer which fixes up Java 1.1-style
synchronized blocks just enough for Fernflower to be able to decompile
them cleanly. (It doesn't add a recursive try/catch, as Fernflower
ignores them.)
Signed-off-by: Graham <gpe@openrs2.dev>
The unsigned client has a Class.forName() method with two differences:
* The NoClassDefFoundError is created with a slightly different sequence
of instructions.
* The arms of the if/else statement for initializing the synthetic field
if it is null are swapped.
This commit adds support for translating Class.forName() methods with
either or both of these differences to the modern LDC form.
Signed-off-by: Graham <gpe@openrs2.dev>
game_unpacker.dat is the name of the file when downloaded in the
.jagex_cache_32/runescape directory. However, the other files containing
code are all named after the files on the web/JAGGRAB server.
This commit uses unpackclass.pack for consistency with all the other
files.
Signed-off-by: Graham <gpe@openrs2.dev>
