Link PlusArg to emulator command line options

- adds a mutable singleton (PlusArgArtefacts) to store information
  about Rocket PlusArgs
- adds methods to PlusArgArtefacts to emit C snippets that are
  consumed by emulator.cc for correct argument parsing and help text
  generation
- emits snippets in $(CONFIG).plusArgs via BaseCoreplex-set
  ElaborationArtefacts
- modify emulator/Makefrag-verilator to include $(CONFIG).plusArgs
- cleanup help text (docstring) for existing PlusArgs

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@gmail.com>

csrc/emulator.cc

@@ -15,12 +15,20 @@
 #include <unistd.h>
 #include <getopt.h>
 
-//TODO: GENERATE THESE AUTOMATICALLY!
-static const char * verilog_plusargs [] = { "max-core-cycles",
-                                            "jtag_rbb_enable",
-                                            "tilelink_timeout",
-                                            0};
-
+// For option parsing, which is split across this file, Verilog, and
+// FESVR's HTIF, a few external files must be pulled in. The list of
+// files and what they provide is enumerated:
+//
+// $RISCV/include/fesvr/htif.h:
+//   defines:
+//     - HTIF_USAGE_OPTIONS
+//     - HTIF_LONG_OPTIONS_OPTIND
+//     - HTIF_LONG_OPTIONS
+// $(ROCKETCHIP_DIR)/generated-src(-debug)?/$(CONFIG).plusArgs:
+//   defines:
+//     - PLUSARG_USAGE_OPTIONS
+//   variables:
+//     - static const char * verilog_plusargs
 
 extern dtm_t* dtm;
 extern remote_bitbang_t * jtag;
@@ -66,7 +74,7 @@ EMULATOR OPTIONS\n\
 #if VM_TRACE == 0
   fputs("\
 \n\
-EMULATOR OPTIONS (only supported in debug build -- try `make debug`)\n",
+EMULATOR DEBUG OPTIONS (only supported in debug build -- try `make debug`)\n",
         stdout);
 #endif
   fputs("\
@@ -74,14 +82,7 @@ EMULATOR OPTIONS (only supported in debug build -- try `make debug`)\n",
   -x, --dump-start=CYCLE   Start VCD tracing at CYCLE\n\
        +dump-start\n\
 ", stdout);
-  fputs("\
-\n\
-VERILOG PLUSARGS (accepted by the Verilog itself):\n" , stdout);
-  const char ** vpa = &verilog_plusargs[0];
-  while (*vpa) {
-    fprintf(stdout, "  +%s=...\n", *vpa);
-    vpa ++;
-  }
+  fputs("\n" PLUSARG_USAGE_OPTIONS, stdout);
   fputs("\n" HTIF_USAGE_OPTIONS, stdout);
   printf("\n"
 "EXAMPLES\n"
@@ -95,7 +96,11 @@ VERILOG PLUSARGS (accepted by the Verilog itself):\n" , stdout);
 #endif
 "  - run an ELF (you wrote, called 'hello') using the proxy kernel:\n"
 "    %s pk hello\n",
-         program_name, program_name, program_name, program_name);
+         program_name, program_name, program_name
+#if VM_TRACE
+         , program_name
+#endif
+         );
 }
 
 int main(int argc, char** argv)
@@ -204,7 +209,8 @@ int main(int argc, char** argv)
             }
             htif_option++;
           }
-          std::cerr << argv[0] << ": invalid HTIF legacy plus-arg \"" << arg << "\"\n";
+          std::cerr << argv[0] << ": invalid plus-arg (Verilog or HTIF) \""
+                    << arg << "\"\n";
           c = '?';
         }
         goto retry;

emulator/Makefrag-verilator

@@ -60,7 +60,7 @@ VERILATOR_FLAGS := --top-module $(MODEL) \
   --output-split-cfuncs 20000 \
 	-Wno-STMTDLY --x-assign unique \
   -I$(base_dir)/vsrc \
-  -O3 -CFLAGS "$(CXXFLAGS) -DVERILATOR -DTEST_HARNESS=V$(MODEL) -include $(base_dir)/csrc/verilator.h"
+  -O3 -CFLAGS "$(CXXFLAGS) -DVERILATOR -DTEST_HARNESS=V$(MODEL) -include $(base_dir)/csrc/verilator.h -include $(generated_dir)/$(CONFIG).plusArgs"
 cppfiles = $(addprefix $(base_dir)/csrc/, $(addsuffix .cc, $(CXXSRCS)))
 headers = $(wildcard $(base_dir)/csrc/*.h)
 

src/main/scala/coreplex/BaseCoreplex.scala

@@ -21,6 +21,7 @@ abstract class BareCoreplexModule[+L <: BareCoreplex](_outer: L) extends LazyMod
   ElaborationArtefacts.add("graphml", outer.graphML)
   ElaborationArtefacts.add("dts", outer.dts)
   ElaborationArtefacts.add("json", outer.json)
+  ElaborationArtefacts.add("plusArgs", PlusArgArtefacts.serialize)
   println(outer.dts)
 }
 

src/main/scala/rocket/RocketCore.scala

@@ -724,7 +724,7 @@ class Rocket(implicit p: Parameters) extends CoreModule()(p)
 
   val max_core_cycles = PlusArg("max-core-cycles",
     default = 0,
-    docstring = "Maximum Core Clock cycles simulation may run before timeout. Ignored if 0 (Default).")
+    docstring = "Kill the emulation after INT rdtime cycles. Off if 0.")
   when (max_core_cycles > UInt(0)) {
     assert (csr.io.time < max_core_cycles, "Maximum Core Cycles reached.")
   }

src/main/scala/tilelink/Monitor.scala

@@ -442,7 +442,8 @@ class TLMonitor(args: TLMonitorArgs) extends TLMonitorBase(args)
     inflight := (inflight | a_set) & ~d_clr
 
     val watchdog = RegInit(UInt(0, width = 32))
-    val limit = PlusArg("tilelink_timeout")
+    val limit = PlusArg("tilelink_timeout",
+      docstring="Kill emulation after INT waiting TileLink cycles. Off if 0.")
     assert (!inflight.orR || limit === UInt(0) || watchdog < limit, "TileLink timeout expired" + extra)
 
     watchdog := watchdog + UInt(1)

src/main/scala/util/PlusArg.scala

@@ -4,6 +4,8 @@ package freechips.rocketchip.util
 
 import Chisel._
 
+case class PlusArgInfo(default: Int, docstring: String)
+
 class plusarg_reader(val format: String, val default: Int, val docstring: String) extends BlackBox(Map(
     "FORMAT"  -> chisel3.core.StringParam(format),
     "DEFAULT" -> chisel3.core.IntParam(default))) {
@@ -20,6 +22,42 @@ object PlusArg
   // Add a docstring to document the arg, which can be dumped in an elaboration
   // pass.
 
-  def apply(name: String, default: Int = 0, docstring: String = ""): UInt =
+  def apply(name: String, default: Int = 0, docstring: String = ""): UInt = {
+    PlusArgArtefacts.append(name, default, docstring)
     Module(new plusarg_reader(name + "=%d", default, docstring)).io.out
+  }
+}
+
+object PlusArgArtefacts {
+  private var artefacts: Map[String, PlusArgInfo] = Map.empty
+
+  /* Add a new PlusArg */
+  def append(name: String, default: Int, docstring: String): Unit =
+    artefacts = artefacts ++ Map(name -> PlusArgInfo(default, docstring))
+
+  /* From plus args, generate help text */
+  private def serializeHelp(tab: String = ""): String = artefacts
+    .map{ case(arg, PlusArgInfo(default, docstring)) =>
+      s"""|$tab+$arg=INT\\n\\
+          |$tab${" "*20}$docstring\\n\\
+          |$tab${" "*22}(default=$default)""".stripMargin }.toSeq
+    .mkString("\\n\\\n") ++ "\""
+
+  /* From plus args, generate a char array of their names */
+  private def serializeArray(tab: String = ""): String = {
+    val prettyTab = tab + " " * 44 // Length of 'static const ...'
+    s"${tab}static const char * verilog_plusargs [] = {\\\n" ++
+      artefacts
+        .map{ case(arg, _) => s"""$prettyTab"$arg",\\\n""" }
+        .mkString("")++
+    s"${prettyTab}0};"
+  }
+
+  /* Generate C code to be included in emulator.cc that helps with
+   * argument parsing based on available Verilog PlusArgs */
+  def serialize(): String =
+    s"""|#define PLUSARG_USAGE_OPTIONS \"EMULATOR VERILOG PLUSARGS\\n\\
+        |${serializeHelp(" "*7)}
+        |${serializeArray()}
+        |""".stripMargin
 }