How to start
How to start
Setup the developement environment
- Install the most recent FPC release for your operanting system, get it here
- Get the lastest FPC source via subversion, read here how to do so.
- Test your setup:
- Change to the directory fpc
- type make all and test see if it works without problems. If you've problems with the build, check the Build FAQ.
- If you wish to do so, you can install the newly generated compiler with make install.
Now you're ready to modify the compiler.
Directory layout of the compiler
The compiler sources are located in fpc/compiler and it's subdirectories.
- fpc/: the main directory
- compiler/: files common for all targets processors. The processor specific files are in subdirectories
- alpha/: The processor specific files for the alpha
- powerpc/: The processor specific files for the PowerPC
- ...
- sparc/: The processor specific files for the SPARC
- systems/: It contains the information files for the supported operating systems. [ 1 ]
- msg/: It contains the compiler messages in various languages.
- utils/: it contains mainly help programs for compiler development. The are usually not important in the beginning.
- compiler/: files common for all targets processors. The processor specific files are in subdirectories
Notes
[1]
The i_*.pas files contain the information which is necessary for either hosting or building a compiler compiling for this target.
The t_*.pas files contain the code which is necessary if a compiler is built for compiling for this particular target.
Building the compiler
To build the compiler only, a make in fpc/compiler is enough. However, if you want to test the generated compiler and you aren't building a cross compiler, better do a make cycle. This tests if the modified compiler can compile itself and the rtl.
Building a cross compiler
Building a cross compiler for another processor target is simple as well, just do a make CPU_TARGET=<processor target>. Possible processor targets are: arm, ia64, i386, powerpc, sparc and x86_64. Some of them might not work currently.
Testing changes
When doing changes, it is always good to test this changes. One possibilty to do so is running the testsuite.
Running the testsuite
cd fpc make clean all cd tests make clean all digest
You'll get something like at the end:
... /FPC/home/fpc/bin/digest output/i386-linux/log Total = 2975 (28:2947) Total number of compilations = 1692 (12:1680) Successfully compiled = 1361 Successfully failed = 319 Compilation failures = 12 Compilation that did not fail while they should = 0 Total number of runs = 1283 (16:1267) Successful runs = 1267 Failed runs = 16 ...
The important line is
Total = 2975 (28:2947)
It shows how much tests were run: 2975, how much failed: 28 and now much succeded: 2947. If you want to know what failed, see fpc/tests/output/<target>/longlog and fpc/tests/output/<target>/log.
Recommended readings
Unfortunately, there is no documentation about the internals of the 1.9.x compiler yet. However, there is a documentation of the internal of the 1.0.x which should give first clues: http://www.stack.nl/~marcov/comparch.pdf
Further, some information about the 1.9.x will be collected here: FPC internals