Added development guide

docs/Development.md

@@ -0,0 +1,76 @@
+---
+layout: main
+title: Development Guide
+---
+
+# Development Guide
+
+- [Introduction](#introduction)
+- [Environment](#environment)
+- [Building](#building)
+- [Testing a Build](#testing-a-build)
+- [Debugging the Runtime](#debugging-the-runtime)
+
+## Introduction
+
+This document provides some basic instructions for developing Cyclone itself - the compiler, interpreter, and libraries. Some of this information may also be applicable when troubleshooting problems with the runtime and/or compiled programs.
+
+## Environment
+
+During development it is a good idea to clone the `cyclone-bootstrap` repository as well as the `cyclone` one. Place both directories in the same parent directory and you can use `sync.sh` to copy individual compiled files to `cyclone-bootstrap`, or `make bootstrap` to copy everything.
+
+## Building
+
+Please use cyclone-bootstrap if you are installing Cyclone on a machine for the first time. Otherwise, if you already have a copy of Cyclone installed you can build from Scheme source. 
+
+The following prerequisites are required:
+
+- libck (see install instructions)
+- make
+- gcc
+
+From the source directory, use the following commands to build and install:
+
+    $ make
+    $ make test
+    $ sudo make install
+    $ cyclone
+    
+By default everything is installed under `/usr/local`. This may be changed by passing a different `PREFIX`. For example:
+
+    make PREFIX=/home/me install
+
+## Testing a Build
+
+`make test` may be used to perform basic testing. 
+
+To make sure everything works, install a modified copy of Cyclone and run the following to rebuild the libraries, compiler, interpreter, and examples from source:
+
+    $ make clean
+    $ make
+    $ make test
+    $ make bootstrap
+
+This confirms that the compiler - with any changes - can still be built from source, and syncs any changes up to `cyclone-bootstrap`. Before checking in a set of changes or releasing a build it is also a good idea to do a rebuild of the bootstrap repo also, to make sure it still works.
+
+## Debugging the Runtime
+
+Cyclone should never segfault unless there is a bug in the runtime/compiler. To debug a segfault using the C compiler's tools, first rebuilt Cyclone with debugging turned on. With GCC, you can do this by changing two lines at the top of `Makefile.config` to use the `-g` option instead of `-O2`. 
+
+For example:
+
+    CFLAGS       ?= -g -Wall -Iinclude -L.
+    COMP_CFLAGS  ?= -g -Wall -I$(PREFIX)/include -L$(PREFIX)/lib
+
+Then rebuild/reinstall everything. This may be easiest to do using the [cyclone-bootstrap](https://github.com/justinethier/cyclone-bootstrap) repository; just modify `Makefile.config` and follow the install instructions.
+
+Now that the C compiler is producing debugging information, you can use `gdb` to debug the segfault directly:
+
+    $ gdb ./crashing-program
+    (gdb) run
+
+If you need to specify any command line arguments to the program:
+
+    (gdb) run arg1 arg2 ...
+
+At this point when the program crashes you should be able to see exactly where it failed. If it failed in `runtime.c` or one of the native C files, it should be straightforward to figure out the problem. If the crash is in a C file generated by Cyclone, the problem will be harder to debug, because likely the compiler either generated code incorrectly or the compiler did not catch an error (such as a missing function parameter) and generated bad code as a result.

index.md

@@ -50,6 +50,8 @@ Documentation
 
 - The [User Manual](docs/User-Manual) covers in detail how to use Cyclone, and provides information and API documentation on the Scheme language features implemented by Cyclone.
 
+- There is a [Development Guide](docs/Development.md) with instructions for common tasks when hacking on the compiler itself.
+
 - Cyclone's [Garbage Collector](docs/Garbage-Collector) is documented at a high-level. This document includes details on extending Cheney on the MTA to support multiple stacks and fusing that approach with a tri-color marking collector.
 
 - The [Benchmarks](docs/Benchmarks) page compares the performance of Cyclone with other R<sup>7</sup>RS Schemes using a common set of benchmarks.