Remove nprocs from cfg_t

Now we have hartids, we can remove nprocs so that we have a single
source of truth.

riscv/cfg.h

@@ -54,13 +54,12 @@ class cfg_t
 {
 public:
   cfg_t(std::pair<reg_t, reg_t> default_initrd_bounds,
-        const char *default_bootargs, size_t default_nprocs,
+        const char *default_bootargs,
         const char *default_isa, const char *default_priv,
         const std::vector<mem_cfg_t> &default_mem_layout,
         const std::vector<int> default_hartids)
     : initrd_bounds(default_initrd_bounds),
       bootargs(default_bootargs),
-      nprocs(default_nprocs),
       isa(default_isa),
       priv(default_priv),
       mem_layout(default_mem_layout),
@@ -70,13 +69,14 @@ public:
 
   cfg_arg_t<std::pair<reg_t, reg_t>> initrd_bounds;
   cfg_arg_t<const char *>            bootargs;
-  cfg_arg_t<size_t>                  nprocs;
   cfg_arg_t<const char *>            isa;
   cfg_arg_t<const char *>            priv;
   cfg_arg_t<std::vector<mem_cfg_t>>  mem_layout;
   std::optional<reg_t>               start_pc;
   cfg_arg_t<std::vector<int>>        hartids;
   bool                               explicit_hartids;
+
+  size_t nprocs() const { return hartids().size(); }
 };
 
 #endif

riscv/sim.cc

@@ -62,8 +62,6 @@ sim_t::sim_t(const cfg_t *cfg, const char* varch, bool halted, bool real_time_cl
     remote_bitbang(NULL),
     debug_module(this, dm_config)
 {
-  assert(cfg->hartids().size() == cfg->nprocs());
-
   signal(SIGINT, &handle_signal);
 
   sout_.rdbuf(std::cerr.rdbuf()); // debug output goes to stderr by default

spike_main/spike.cc

@@ -272,9 +272,10 @@ int main(int argc, char** argv)
     .support_haltgroups = true,
     .support_impebreak = true
   };
+  cfg_arg_t<size_t> nprocs(1);
+
   cfg_t cfg(/*default_initrd_bounds=*/std::make_pair((reg_t)0, (reg_t)0),
             /*default_bootargs=*/nullptr,
-            /*default_nprocs=*/1,
             /*default_isa=*/DEFAULT_ISA,
             /*default_priv=*/DEFAULT_PRIV,
             /*default_mem_layout=*/parse_mem_layout("2048"),
@@ -332,7 +333,7 @@ int main(int argc, char** argv)
 #ifdef HAVE_BOOST_ASIO
   parser.option('s', 0, 0, [&](const char* s){socket = true;});
 #endif
-  parser.option('p', 0, 1, [&](const char* s){cfg.nprocs = atoul_nonzero_safe(s);});
+  parser.option('p', 0, 1, [&](const char* s){nprocs = atoul_nonzero_safe(s);});
   parser.option('m', 0, 1, [&](const char* s){cfg.mem_layout = parse_mem_layout(s);});
   // I wanted to use --halted, but for some reason that doesn't work.
   parser.option('H', 0, 0, [&](const char* s){halted = true;});
@@ -462,11 +463,11 @@ int main(int argc, char** argv)
 #endif
 
   if (cfg.explicit_hartids) {
-    if (cfg.nprocs.overridden() && (cfg.nprocs() != cfg.hartids().size())) {
+    if (nprocs.overridden() && (nprocs() != cfg.nprocs())) {
       std::cerr << "Number of specified hartids ("
-                << cfg.hartids().size()
+                << cfg.nprocs()
                 << ") doesn't match specified number of processors ("
-                << cfg.nprocs() << ").\n";
+                << nprocs() << ").\n";
       exit(1);
     }
   } else {
@@ -474,8 +475,8 @@ int main(int argc, char** argv)
     // explicit_hartids flag (which means that downstream code can know that
     // we've only set the number of harts, not explicitly chosen their IDs).
     std::vector<int> default_hartids;
-    default_hartids.reserve(cfg.nprocs());
-    for (size_t i = 0; i < cfg.nprocs(); ++i) {
+    default_hartids.reserve(nprocs());
+    for (size_t i = 0; i < nprocs(); ++i) {
       default_hartids.push_back(i);
     }
     cfg.hartids = default_hartids;