From 00fba627118fb536686b3d30f3b81f71b513cd51 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Marcin=20Ko=C5=9Bcielnicki?= Date: Sat, 1 Feb 2020 10:21:19 +0100 Subject: [PATCH] json: remove the 32-bit parameter special case Before, the rules for encoding parameters in JSON were as follows: - if the parameter is not a string: - if it is exactly 32 bits long and there are no z or x bits, emit it as an int - otherwise, emit it as a string made of 0/1/x/z characters - if the parameter is a string: - if it contains only 0/1/x/z characters, append a space at the end to distinguish it from a non-string - otherwise, emit it directly However, this caused a problem in the json11 parser used in nextpnr: yosys emits unsigned ints, and nextpnr parses them as signed, using the value of INT_MIN for values that overflow the signed int range. This caused destruction of LUT5 initialization values. Since both nextpnr and yosys parser can also accept 32-bit parameters in the same encoding as other widths, let's just remove that special case. The old behavior is still left behind a `-compat-int` flag, in case someone relies on it. --- backends/json/json.cc | 38 ++++++++++++++++++++++++++++---------- 1 file changed, 28 insertions(+), 10 deletions(-) diff --git a/backends/json/json.cc b/backends/json/json.cc index 107009ee4..5c67cb857 100644 --- a/backends/json/json.cc +++ b/backends/json/json.cc @@ -33,6 +33,7 @@ struct JsonWriter std::ostream &f; bool use_selection; bool aig_mode; + bool compat_int_mode; Design *design; Module *module; @@ -42,8 +43,9 @@ struct JsonWriter dict sigids; pool aig_models; - JsonWriter(std::ostream &f, bool use_selection, bool aig_mode) : - f(f), use_selection(use_selection), aig_mode(aig_mode) { } + JsonWriter(std::ostream &f, bool use_selection, bool aig_mode, bool compat_int_mode) : + f(f), use_selection(use_selection), aig_mode(aig_mode), + compat_int_mode(compat_int_mode) { } string get_string(string str) { @@ -102,8 +104,7 @@ struct JsonWriter if (state < 2) str += " "; f << get_string(str); - } else - if (GetSize(value) == 32 && value.is_fully_def()) { + } else if (compat_int_mode && GetSize(value) == 32 && value.is_fully_def()) { if ((value.flags & RTLIL::ConstFlags::CONST_FLAG_SIGNED) != 0) f << stringf("%d", value.as_int()); else @@ -294,6 +295,10 @@ struct JsonBackend : public Backend { log(" -aig\n"); log(" include AIG models for the different gate types\n"); log("\n"); + log(" -compat-int\n"); + log(" emit 32-bit fully-defined parameter values directly\n"); + log(" as JSON numbers (for compatibility with old parsers)\n"); + log("\n"); log("\n"); log("The general syntax of the JSON output created by this command is as follows:\n"); log("\n"); @@ -368,10 +373,9 @@ struct JsonBackend : public Backend { log("connected to a constant driver are denoted as string \"0\", \"1\", \"x\", or\n"); log("\"z\" instead of a number.\n"); log("\n"); - log("Numeric 32-bit parameter and attribute values are written as decimal values.\n"); - log("Bit verctors of different sizes, or ones containing 'x' or 'z' bits, are written\n"); - log("as string holding the binary representation of the value. Strings are written\n"); - log("as strings, with an appended blank in cases of strings of the form /[01xz]* */.\n"); + log("Bit vectors (including integers) are written as string holding the binary"); + log("representation of the value. Strings are written as strings, with an appended"); + log("blank in cases of strings of the form /[01xz]* */.\n"); log("\n"); log("For example the following Verilog code:\n"); log("\n"); @@ -495,6 +499,7 @@ struct JsonBackend : public Backend { void execute(std::ostream *&f, std::string filename, std::vector args, RTLIL::Design *design) YS_OVERRIDE { bool aig_mode = false; + bool compat_int_mode = false; size_t argidx; for (argidx = 1; argidx < args.size(); argidx++) @@ -503,13 +508,17 @@ struct JsonBackend : public Backend { aig_mode = true; continue; } + if (args[argidx] == "-compat-int") { + compat_int_mode = true; + continue; + } break; } extra_args(f, filename, args, argidx); log_header(design, "Executing JSON backend.\n"); - JsonWriter json_writer(*f, false, aig_mode); + JsonWriter json_writer(*f, false, aig_mode, compat_int_mode); json_writer.write_design(design); } } JsonBackend; @@ -530,6 +539,10 @@ struct JsonPass : public Pass { log(" -aig\n"); log(" also include AIG models for the different gate types\n"); log("\n"); + log(" -compat-int\n"); + log(" emit 32-bit fully-defined parameter values directly\n"); + log(" as JSON numbers (for compatibility with old parsers)\n"); + log("\n"); log("See 'help write_json' for a description of the JSON format used.\n"); log("\n"); } @@ -537,6 +550,7 @@ struct JsonPass : public Pass { { std::string filename; bool aig_mode = false; + bool compat_int_mode = false; size_t argidx; for (argidx = 1; argidx < args.size(); argidx++) @@ -549,6 +563,10 @@ struct JsonPass : public Pass { aig_mode = true; continue; } + if (args[argidx] == "-compat-int") { + compat_int_mode = true; + continue; + } break; } extra_args(args, argidx, design); @@ -569,7 +587,7 @@ struct JsonPass : public Pass { f = &buf; } - JsonWriter json_writer(*f, true, aig_mode); + JsonWriter json_writer(*f, true, aig_mode, compat_int_mode); json_writer.write_design(design); if (!filename.empty()) { -- 2.30.2