Add contributing and architecture

ARCHITECTURE.md

@@ -0,0 +1,27 @@
+# Architecture
+This file provides information on how FernFlower is structured, with descriptions of how each part of the codebase works.
+
+## Terms
+FernFlower uses a large amount of terms and shorthand names within its code, for which explanations are provided here.
+The first name is the full name and the names in parentheses are the shorthand names that are used throughout the code.
+* Exprent (expr, exp) Refers to an expression that FernFlower uses to create the java code, such as a constant or method invocation.
+* Statement (stat) Refers to a statement within the code used to structure the code, such as an if statement or a loop.
+
+## The decompilation process
+When a method gets decompiled, it passes through multiple stages through which it is converted from bytecode to java code.
+At a high level, this process consists of bytecode reading, instruction sequencing, control flow analysis, code structuring, and java writing.
+Each of these steps will be outlined in detail below.
+
+### Bytecode reading and instruction sequencing
+This is the simplest part of the process, as it just reads the bytecode bytes out of the code struct and initializing them. This takes place in `StructMethod#parseBytecode`.
+
+### Control Flow Analysis
+Control flow analysis is where the bytecode is analyzed into basic blocks, SSA is run, and the dominator tree is generated to help with analysis and code inference.
+Most of this processing happens in `MethodProcessorRunnable.codeToJava`.
+
+### Code structuring
+Right after the control flow analysis, the basic blocks are turned into structured code within the same `MethodProcessorRunnable.codeToJava` method. This creates an intermediate
+representation of the method that can be then turned into java code.
+
+### Java writing
+`ClassWriter#methodToJava` takes the intermediate representation (comprised of statements and exprents) and structures that into java code which is then written.

CONTRIBUTING.md

@@ -0,0 +1,39 @@
+# Contributing
+Welcome! Thank you for taking an interest in contributing to Quiltflower.
+
+## Before making a pull request
+* Please read the [Quilt Code Of Conduct](https://quiltmc.org/community/code-of-conduct.html) first!
+* The ARCHITECTURE.md file in the repository contains technical information on how Quiltflower is structured. Reading that will greatly help with familiarizing yourself with the codebase and with PR development.
+* It's highly recommended to talk about the changes you are making [on the Quilt toolchain discord](https://discord.quiltmc.org/toolchain) before submitting them.
+* Check out the issue tracker and roadmap! You can find good things to contribute there.
+
+## Good things to contribute
+* Improvements to the readability of the decompiled code.
+* New feature support for the decompiler.
+* Optimization, to make it run faster and use fewer resources.
+* Tests! Tests are always appreciated.
+
+## Code Style and guidelines
+While the code inherited from FernFlower varies with its style and syntax, it's expected that pull requests stick to our established code style.
+* We use UpperCamelCase for class names, camelCase for method, variable, local variable, and field names, and UPPER_SNAKE_CASE for static final fields. Please always qualify instance fields with a `this.` qualifier.
+* Please try to keep pull requests small and self-contained! It makes reviewing and maintaining the patch much easier.
+* FernFlower's code is barely documented, but patches should add documentation in a high level manner so that other devs can understand what is going on within the patch, and any idiosyncrasies within.
+* When submitting patches, it is also recommended to cite the relevant portion of the Java Language Specification for future reference and for getting a better understanding of the code that has to be generated by the patch.
+
+## Tests
+* Quiltflower uses a large and expansive test suite to ensure that patches don't cause any regressions. Please make sure that your patches don't break any of the tests!
+* In the case that you're adding a new feature to the decompiler, it's acceptable to modify failing tests to make them succeed. Please make a note of this in the pull request.
+* When contributing, you should add new tests that cover the area of code that you are targeting. Having more tests makes the decompiler more robust, so it's always appreciated.
+* Please also test your code changes against the Minecraft codebase to ensure that your change is properly applied on there too, and does not break any existing code.
+
+## Resources
+FernFlower is a very complex and involved bit of software, and there's a lot going on in a rather questionable structure. Naturally, understanding it all is a challenge so various resources are provided here to aid with the process.
+* Knowing how java bytecode works is essential. You can find the detailed description of all the opcodes [here](https://docs.oracle.com/javase/specs/jvms/se16/html/jvms-6.html#jvms-6.5) or a simple list of them [here.](https://en.wikipedia.org/wiki/Java_bytecode_instruction_listings)
+* Graph theory comes up frequently in the statement analysis portion of FernFlower. It's useful knowing about [Basic Blocks](https://en.wikipedia.org/wiki/Basic_block), [Control Flow Graphs](https://en.wikipedia.org/wiki/Control-flow_graph), and [Dominators.](https://en.wikipedia.org/wiki/Dominator_(graph_theory))
+* [Static Single Assignment Form](https://en.wikipedia.org/wiki/Static_single_assignment_form) is also used widely to track variables and their versions within the decompilation stages.
+* The [Java Language Specification](https://docs.oracle.com/javase/specs/jls/se16/html/), while dense, is a good source of information regarding language features.
+* The ARCHITECTURE.md file in the repository contains important information about how FernFlower is structured.
+* The [Discord server](https://discord.quiltmc.org/toolchain) contains many people who have worked with the code before, so any remaining questions are best asked there.
+
+## License
+* Quiltflower is licensed under Apache Version 2.0. By submitting a patch you are agreeing to license your code under it. Please do not submit pull requests containing code you do not have the rights to!

LICENSE.md

@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

README.md

@@ -9,6 +9,9 @@ Changes include:
 
 When pulling from upstream, use https://github.com/fesh0r/fernflower
 
+### Contributing
+To contribute, please check out CONTRIBUTING.md and ARCHITECTURE.md!
+
 #### Special Thanks
 * Jetbrains- For maintaining Fernflower
 * Forge Team- For maintaining ForgeFlower