The only difference between "RTLIL" and "ILANG" is that the latter is
the text representation of the former, as opposed to the in-memory
graph representation. This distinction serves no purpose but confuses
people: it is not obvious that the ILANG backend writes RTLIL graphs.
Passes `write_ilang` and `read_ilang` are provided as aliases to
`write_rtlil` and `read_rtlil` for compatibility.
9dedac50 introduced this harmless but disconcerting warning, which was emitted
when abc/ did not yet exist and was about to be cloned:
/bin/sh: line 0: cd: abc: No such file or directory
This includes the following significant changes:
* Patching ezsat and minisat to disable resource limiting code
on WASM/WASI, since the POSIX functions they use are unavailable.
* Adding a new definition, YOSYS_DISABLE_SPAWN, present if platform
does not support spawning subprocesses (i.e. Emscripten or WASI).
This definition hides the definition of `run_command()`.
* Adding a new Makefile flag, DISABLE_SPAWN, present in the same
condition. This flag disables all passes that require spawning
subprocesses for their function.
By operating at a layer of abstraction over the rather clumsy Intel primitives,
we can avoid special hacks like `dffinit -highlow` in favour of simple techmapping.
This also makes the primitives much easier to manipulate, and more descriptive
(no more cyclonev_lcell_comb to mean anything from a LUT2 to a LUT6).
The make targets echo-yosys-ver, echo-git-ver and echo-abc-rev can be
used to programmatically extract contents of make variables for external
scripts. Unfortunately, when a Makefile.conf exists, its contents would
also be echoed, making the output almost unusable. This patch
selectively disables this functionality for these special targets.