1. mmap all memory always, without explicit mmap calls in the program.
This makes lots of things much easier and removes lots of code.
Makes mmap not a special syscall and allows to fuzz without mmap enabled.
2. Change address assignment algorithm.
Current algorithm allocates unmapped addresses too frequently
and allows collisions between arguments of a single syscall.
The new algorithm analyzes actual allocations in the program
and places new arguments at unused locations.
This breaks circular dependency between:
sysgen -> sys/linux -> sys -> sysgen
With this circular dependency it is very difficult to
update format of generated descriptions because sysgen does not build.
Info about targets (like C arch/CFLAGS) is required in multiple places:
extract.sh
syz-extract
syz-sysgen
csource
vm/qemu
...
Consolidate it in one place and use that in syz-sysgen.
Large overhaul moves syscalls and arg types from sys to prog.
Sys package now depends on prog and contains only generated
descriptions of syscalls.
Introduce prog.Target type that encapsulates all targer properties,
like syscall list, ptr/page size, etc. Also moves OS-dependent pieces
like mmap call generation from prog to sys.
Update #191
All other types have optional underlying type as the last argument.
Proc have it as first. This creates very irregular syntax and
complicates parsing. Make type the last argument.
Note: this is a breaking change if you have descriptions on the side.
We currently use uintptr for all values.
This won't work for 32-bit archs.
Moreover in some cases we use uintptr but assume
that it is always 64-bits (e.g. in encodingexec).
Switch everything to uint64.
Update #324
