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cxxrtl: opt also optimises the design with Yosys.

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This has a significant result on sim speed.
This commit is contained in:
Asherah Connor 2024-06-27 19:12:24 +03:00
parent 02e500d295
commit 7aa12417e6
1 changed files with 28 additions and 5 deletions
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33
niar/cxxrtl.py
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@ -105,24 +105,45 @@ def main(np: Project, args):
cr = CommandRunner(force=args.force)
with logtime(logging.DEBUG, "elaboration"):
il_path = np.path.build(f"{np.name}.il")
il_path = np.path.build(f"{np.name}.cc.il")
rtlil_text = rtlil.convert(design, name=np.name, platform=platform)
with open(il_path, "w") as f:
f.write(rtlil_text)
cxxrtl_cc_path = np.path.build(f"{np.name}.cc")
yosys_script_path = _make_absolute(np.path.build(f"{np.name}-cxxrtl.ys"))
yosys_script_path = _make_absolute(np.path.build(f"{np.name}.cc.ys"))
black_boxes = {}
with open(yosys_script_path, "w") as f:
for box_source in black_boxes.values():
f.write(f"read_rtlil <<rtlil\n{box_source}\nrtlil\n")
f.write(f"read_rtlil {_make_absolute(il_path)}\n")
# TODO: do we want to call any opt passes here?
if args.optimize.opt_rtl:
f.write("opt\n")
f.write(f"write_rtlil {_make_absolute(il_path)}.opt\n")
f.write(f"write_cxxrtl -header {_make_absolute(cxxrtl_cc_path)}\n")
def rtlil_to_cc():
yosys.run(["-q", yosys_script_path])
# "opt" without "proc" generates a bunch of warnings like:
#
# Warning: Ignoring module ili9341spi.initter because it contains
# processes (run 'proc' command first).
#
# Those passes warn and don't run (instead of removing things we
# care about), so just let them. We don't want to run "proc" --- it
# dovetails poorly with CXXRTL and the result is slower than had we
# done nothing at all. Note the following option taken by
# "write_cxxrtl":
#
# -noproc
#
# don't convert processes to netlists. in most designs,
# converting processes significantly improves evaluation
# performance at the cost of slight increase in compilation
# time.
#
# Presumably "proc" does it worse, for CXXRTL's purposes.
yosys.run(["-q", yosys_script_path], ignore_warnings=True)
cr.add_process(rtlil_to_cc,
infs=[il_path, yosys_script_path],
@ -198,7 +219,9 @@ def main(np: Project, args):
else:
cmd = [
"c++",
*cxxflags,
# Hard to imagine these flags having any effect.
*(["-O3"] if args.optimize.opt_app else ["-O0"]),
*(["-g"] if args.debug else []),
*cc_o_paths,
"-o",
exe_o_path,