Add --placer option and refactor placer selection

Signed-off-by: David Shah <dave@ds0.me>

common/command.cc

@@ -27,6 +27,7 @@
 #include "pybindings.h"
 #endif
 
+#include <boost/algorithm/string/join.hpp>
 #include <boost/filesystem/convenience.hpp>
 #include <boost/program_options.hpp>
 #include <fstream>
@@ -120,6 +121,13 @@ po::options_description CommandHandler::getGeneralOptions()
     general.add_options()("json", po::value<std::string>(), "JSON design file to ingest");
     general.add_options()("seed", po::value<int>(), "seed value for random number generator");
     general.add_options()("randomize-seed,r", "randomize seed value for random number generator");
+
+    general.add_options()(
+            "placer", po::value<std::string>(),
+            std::string("placer algorithm to use; available: " + boost::algorithm::join(Arch::availablePlacers, ", ") +
+                        "; default: " + Arch::defaultPlacer)
+                    .c_str());
+
     general.add_options()("slack_redist_iter", po::value<int>(), "number of iterations between slack redistribution");
     general.add_options()("cstrweight", po::value<float>(), "placer weighting for relative constraint satisfaction");
     general.add_options()("starttemp", po::value<float>(), "placer SA start temperature");
@@ -186,6 +194,17 @@ void CommandHandler::setupContext(Context *ctx)
         settings->set("timing/allowFail", true);
     }
 
+    if (vm.count("placer")) {
+        std::string placer = vm["placer"].as<std::string>();
+        if (std::find(Arch::availablePlacers.begin(), Arch::availablePlacers.end(), placer) ==
+            Arch::availablePlacers.end())
+            log_error("Placer algorithm '%s' is not supported (available options: %s)\n", placer.c_str(),
+                      boost::algorithm::join(Arch::availablePlacers, ", ").c_str());
+        settings->set("placer", placer);
+    } else {
+        settings->set("placer", Arch::defaultPlacer);
+    }
+
     if (vm.count("cstrweight")) {
         settings->set("placer1/constraintWeight", vm["cstrweight"].as<float>());
     }

common/settings.h

@@ -45,7 +45,13 @@ class Settings
         return defaultValue;
     }
 
-    template <typename T> void set(const char *name, T value)
+    template <typename T> void set(const char *name, T value);
+
+  private:
+    Context *ctx;
+};
+
+template <typename T> inline void Settings::set(const char *name, T value)
 {
     IdString id = ctx->id(name);
     auto pair = ctx->settings.emplace(id, std::to_string(value));
@@ -54,9 +60,14 @@ class Settings
     }
 }
 
-  private:
+template <> inline void Settings::set<std::string>(const char *name, std::string value)
-    Context *ctx;
+{
-};
+    IdString id = ctx->id(name);
+    auto pair = ctx->settings.emplace(id, value);
+    if (!pair.second) {
+        ctx->settings[pair.first->first] = value;
+    }
+}
 
 NEXTPNR_NAMESPACE_END
 

docs/archapi.md

@@ -490,3 +490,14 @@ a certain number of different clock signals allowed for a group of bels.
 
 Returns true if a bell in the current configuration is valid, i.e. if
 `isValidBelForCell()` would return true for the current mapping.
+
+
+### static const std::string defaultPlacer
+
+Name of the default placement algorithm for the architecture, if
+`--placer` isn't specified on the command line.
+
+### static const std::vector\<std::string\> availablePlacers
+
+Name of available placer algorithms for the architecture, used
+to provide help for and validate `--placer`.

ecp5/arch.cc

@@ -508,21 +508,21 @@ bool Arch::getBudgetOverride(const NetInfo *net_info, const PortRef &sink, delay
 
 bool Arch::place()
 {
-    // HeAP is the default unless overriden or not built
+    std::string placer = str_or_default(settings, id("placer"), defaultPlacer);
-#ifdef WITH_HEAP
+
-    if (bool_or_default(settings, id("sa_placer"), false)) {
+    if (placer == "heap") {
-#endif
-        if (!placer1(getCtx(), Placer1Cfg(getCtx())))
-            return false;
-#ifdef WITH_HEAP
-    } else {
         PlacerHeapCfg cfg(getCtx());
         cfg.criticalityExponent = 7;
         cfg.ioBufTypes.insert(id_TRELLIS_IO);
         if (!placer_heap(getCtx(), cfg))
             return false;
+    } else if (placer == "sa") {
+        if (!placer1(getCtx(), Placer1Cfg(getCtx())))
+            return false;
+    } else {
+        log_error("ECP5 architecture does not support placer '%s'\n", placer.c_str());
     }
-#endif
+
     permute_luts();
     return true;
 }
@@ -986,4 +986,16 @@ WireId Arch::getBankECLK(int bank, int eclk)
     return getWireByLocAndBasename(Location(0, 0), "G_BANK" + std::to_string(bank) + "ECLK" + std::to_string(eclk));
 }
 
+#ifdef WITH_HEAP
+const std::string Arch::defaultPlacer = "heap";
+#else
+const std::string Arch::defaultPlacer = "sa";
+#endif
+
+const std::vector<std::string> Arch::availablePlacers = {"sa",
+#ifdef WITH_HEAP
+                                                         "heap"
+#endif
+};
+
 NEXTPNR_NAMESPACE_END

ecp5/arch.h

@@ -1045,6 +1045,9 @@ struct Arch : BaseCtx
     IdString id_srmode, id_mode;
 
     mutable std::unordered_map<DelayKey, std::pair<bool, DelayInfo>> celldelay_cache;
+
+    static const std::string defaultPlacer;
+    static const std::vector<std::string> availablePlacers;
 };
 
 NEXTPNR_NAMESPACE_END

ecp5/main.cc

@@ -59,8 +59,6 @@ po::options_description ECP5CommandHandler::getArchOptions()
     specific.add_options()("um5g-45k", "set device type to LFE5UM5G-45F");
     specific.add_options()("um5g-85k", "set device type to LFE5UM5G-85F");
 
-    specific.add_options()("sa-placer", "use pure simulated annealing placer instead of HeAP analytic placer");
-
     specific.add_options()("package", po::value<std::string>(), "select device package (defaults to CABGA381)");
     specific.add_options()("speed", po::value<int>(), "select device speedgrade (6, 7 or 8)");
 
@@ -152,10 +150,6 @@ std::unique_ptr<Context> ECP5CommandHandler::createContext()
         }
     }
     auto ctx = std::unique_ptr<Context>(new Context(chipArgs));
-
-    if (vm.count("sa-placer"))
-        ctx->settings[ctx->id("sa_placer")] = "1";
-
     return ctx;
 }
 

generic/arch.cc

@@ -21,6 +21,7 @@
 #include "nextpnr.h"
 #include "placer1.h"
 #include "router1.h"
+#include "util.h"
 
 NEXTPNR_NAMESPACE_BEGIN
 
@@ -439,7 +440,16 @@ bool Arch::getBudgetOverride(const NetInfo *net_info, const PortRef &sink, delay
 
 // ---------------------------------------------------------------
 
-bool Arch::place() { return placer1(getCtx(), Placer1Cfg(getCtx())); }
+bool Arch::place()
+{
+    std::string placer = str_or_default(settings, id("placer"), defaultPlacer);
+    // FIXME: No HeAP because it needs a list of IO buffers
+    if (placer == "sa") {
+        return placer1(getCtx(), Placer1Cfg(getCtx()));
+    } else {
+        log_error("Generic architecture does not support placer '%s'\n", placer.c_str());
+    }
+}
 
 bool Arch::route() { return router1(getCtx(), Router1Cfg(getCtx())); }
 
@@ -476,4 +486,7 @@ TimingClockingInfo Arch::getPortClockingInfo(const CellInfo *cell, IdString port
 bool Arch::isValidBelForCell(CellInfo *cell, BelId bel) const { return true; }
 bool Arch::isBelLocationValid(BelId bel) const { return true; }
 
+const std::string Arch::defaultPlacer = "sa";
+const std::vector<std::string> Arch::availablePlacers = {"sa"};
+
 NEXTPNR_NAMESPACE_END

generic/arch.h

@@ -240,6 +240,9 @@ struct Arch : BaseCtx
 
     bool isValidBelForCell(CellInfo *cell, BelId bel) const;
     bool isBelLocationValid(BelId bel) const;
+
+    static const std::string defaultPlacer;
+    static const std::vector<std::string> availablePlacers;
 };
 
 NEXTPNR_NAMESPACE_END

ice40/arch.cc

@@ -671,14 +671,17 @@ bool Arch::getBudgetOverride(const NetInfo *net_info, const PortRef &sink, delay
 
 bool Arch::place()
 {
-    if (bool_or_default(settings, id("heap_placer"), false)) {
+    std::string placer = str_or_default(settings, id("placer"), defaultPlacer);
+    if (placer == "heap") {
         PlacerHeapCfg cfg(getCtx());
         cfg.ioBufTypes.insert(id_SB_IO);
         if (!placer_heap(getCtx(), cfg))
             return false;
-    } else {
+    } else if (placer == "sa") {
         if (!placer1(getCtx(), Placer1Cfg(getCtx())))
             return false;
+    } else {
+        log_error("iCE40 architecture does not support placer '%s'\n", placer.c_str());
     }
     if (bool_or_default(settings, id("opt_timing"), false)) {
         TimingOptCfg tocfg(getCtx());
@@ -1205,4 +1208,12 @@ void Arch::assignCellInfo(CellInfo *cell)
     }
 }
 
+const std::string Arch::defaultPlacer = "sa";
+
+const std::vector<std::string> Arch::availablePlacers = {"sa",
+#ifdef WITH_HEAP
+                                                         "heap"
+#endif
+};
+
 NEXTPNR_NAMESPACE_END

ice40/arch.h

@@ -897,6 +897,9 @@ struct Arch : BaseCtx
         IdString glb_net = getWireName(getBelPinWire(bel, id_GLOBAL_BUFFER_OUTPUT));
         return std::stoi(std::string("") + glb_net.str(this).back());
     }
+
+    static const std::string defaultPlacer;
+    static const std::vector<std::string> availablePlacers;
 };
 
 void ice40DelayFuzzerMain(Context *ctx);

ice40/main.cc

@@ -69,8 +69,6 @@ po::options_description Ice40CommandHandler::getArchOptions()
     specific.add_options()("promote-logic",
                            "enable promotion of 'logic' globals (in addition to clk/ce/sr by default)");
     specific.add_options()("no-promote-globals", "disable all global promotion");
-    specific.add_options()("heap-placer",
-                           "use HeAP analytic placer instead of simulated annealing (faster, experimental)");
     specific.add_options()("opt-timing", "run post-placement timing optimisation pass (experimental)");
     specific.add_options()("tmfuzz", "run path delay estimate fuzzer");
     specific.add_options()("pcf-allow-unconstrained", "don't require PCF to constrain all IO");
@@ -178,8 +176,6 @@ std::unique_ptr<Context> Ice40CommandHandler::createContext()
         ctx->settings[ctx->id("opt_timing")] = "1";
     if (vm.count("pcf-allow-unconstrained"))
         ctx->settings[ctx->id("pcf_allow_unconstrained")] = "1";
-    if (vm.count("heap-placer"))
-        ctx->settings[ctx->id("heap_placer")] = "1";
     return ctx;
 }