Improvements to SAW Lab Proofs and Makefiles

[djmorel]

Features

• Updates the SAW labs based on @WeeknightMVP 's comments about relative paths for proofs and specifying targets for Makefiles.
  • Python proof scripts can now be called anywhere!
• Updates the python-saw CI to run SAW labs in a make prove -C format without the need to change directories via cd
• Updated the SAW lab Makefiles to be identical except for their LAB variables
• Updated the SAW.md documentation to reflect these changes

[weaversa]

Great work @djmorel! This makes the dual tasks of development and CI integration work together seamlessly, and provides some very nice examples others can build off of.

I'll approve but wait for @WeeknightMVP to have a say before merging, seeing as he submitted the original issue.

[WeeknightMVP]

Externalizing a LAB variable in Makefiles is nice, as it establishes a consistent process for SAW Remote API builds and proofs -- so consistent that their content after LAB=name is the same. (Except for rotl, where rotl.c would be renamed rotl1.c, and rotl3.c would be renamed rotl.c. Enumerating intermediate files and declaring the last one as the representative makes sense.) This suggests that each lab's Makefile could be DRYed to something like:

# labs/SAW/name/Makefile

LAB=name
# any other variables or rules specific to this lab

include "../prove.mk"  # Nested labs would require more `..`s

# labs/SAW/prove.mk

# Note: Makefile assumes user already started the SAW remote API
# $ start-saw-remote-api

# Variables to hold relative file paths
SRC=src
PROOF=proof
SPECS=specs
ARTIFACTS=artifacts

all: build

build: $(ARTIFACTS)/$(LAB).bc

prove: build
	python3 $(PROOF)/$(LAB).py

clean:
	rm -rf $(ARTIFACTS)

.PHONY: all build prove clean

$(ARTIFACTS)/$(LAB).bc: $(SRC)/$(LAB).c | $(ARTIFACTS)
	clang -c -g -emit-llvm -o $@ $<

$(ARTIFACTS):
	mkdir -p $(ARTIFACTS)

[djmorel]

I'm going to temporarily restore the relative-proofs branch to make the rotl lab use the new Makefile format. I'll also take the opportunity to update SAW.md so to reflect the naming changes @WeeknightMVP proposed.