IDO matching decomp

Matching decompilation of the IRIX Development Option compiler.

The intention is to eventually match all the programs required to build C files to an unlinked binary, namely

• cc - compiler driver, runs everything else as appropriate
• cfe - "C frontend", preprocessor and runs the optimisation and code generation steps
• uopt - optimiser used by -O2
• ugen - code generator used for lower optimisation
• as1 - assembler for compiler-generated assembly

since this process is the most useful for other decompilation projects.

Lower priority but also of interest:

• as0 - assembler for handwritten assembly
• ld (linker) for outputting linked object files
• uld (ucode linker) and umerge (procedure merger) for -O3
• upas frontend for Pascal, possibly of interest since much of IDO is Pascal

Of these,

• cc, cfe, as0 are written in C, cfe also contains Yacc components.
• uopt, ugen, as1, uld, umerge, upas, are written in Pascal.
• ld is unknown at present

State of the repository

The following table specify if each binary has been matched or not, and if it has their functions matching or the whole binary/elf.

Program	5.3 functions	5.3 elf	7.1 functions	7.1 elf
cc	❌	❌	✔️	❌
cfe	❌	❌	❌	❌
uopt	❌	❌	❌	❌
ugen	❌	❌	❌	❌
as1	❌	❌	❌	❌
as0	✔️	❌	❌	❌
ld	❌	❌	❌	❌
uld	❌	❌	❌	❌
umerge	❌	❌	❌	❌
upas	❌	❌	❌	❌
ujoin	❌	❌	❌	❌
usplit	❌	❌	❌	❌

Build dependencies

TODO

python3 -m pip install -U -r requirements.txt

Setup

make setup
make disasm
make

Diff: ./diff.py -mwob --objfile build/src/7.1/cc/cc.o main

Sources

• lib/indy/dev/usr/lib/crt{1,n}.o are from IRISDevelopmentOption7.1.1forIRIX6.4_02-97_812-0625-002.iso