ABC: read_lib args and placeholders #4343
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| @@ -849,6 +861,7 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin | |||
| for (size_t pos = abc_script.find("dretime;"); pos != std::string::npos; pos = abc_script.find("dretime;", pos+1)) | |||
| abc_script = abc_script.substr(0, pos) + "dretime; retime -o {D};" + abc_script.substr(pos+8); | |||
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| // replace placeholders in abc.script and user.script | |||
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Please factor out the substitution operation so that it's not open-coded many times
| } else { | ||
| // read in user script | ||
| std::ifstream ifs(script_file.c_str()); | ||
| if(ifs.is_open()) { |
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Please fix whitespace/indentation in this block
| @@ -876,6 +908,13 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin | |||
| fprintf(f, "%s\n", abc_script.c_str()); | |||
| fclose(f); | |||
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| buffer = stringf("%s/user.script", tempdir_name.c_str()); | |||
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Do we need the abc.script/user.script separation? Why not write both to the same file?
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The abc.script and user.script separation is how it currently works. It basically separates the setup (loading the network and library and later writing it out) from the actual optimization and mapping script.
A different approach (and the one I would like to move in) is to give an option to not use the abc.script part and instead expect it to be part of the custom user.script and then just replace the placeholders in user.script.
This would give full freedom in what people do with ABC, going as far as invoking multiple ABC scripts in parallel and selecting one based one some criteria before returning to Yosys.
| @@ -1743,6 +1782,10 @@ struct AbcPass : public Pass { | |||
| liberty_files.push_back(args[++argidx]); | |||
| continue; | |||
| } | |||
| if (arg == "-liberty_args" && argidx+1 < args.size()) { | |||
Adds a way to give read_lib additional arguments.
This can for example be used to define
-S <slew> -G <gain>so ABC will calculate its internal delay model from the standard cells liberty data. Without this it uses a unit delay model, which may produce worse results.An example use:
I changed it so the placeholders like
{D}are also replaced in user provided scripts. This seems reasonable to me as OpenLane, OpenROAD-flow-scripts etc currently use the same placeholders but have to replace it themself.Additionally, there is a new placeholder called
{tmpdir}, it contains the path to the yosys-abc directory currently being used. This allows users to temporarily store information from their user script.