ecp5: Proof-of-concept using IdStringList for bel names

This uses the new IdStringList API to store bel names for the ECP5. Note
that other arches and the GUI do not yet build with this
proof-of-concept patch.

getBelByName still uses the old implementation and could be more
efficiently implemented with further development.

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

common/archcheck.cc

@@ -36,10 +36,10 @@ void archcheck_names(const Context *ctx)
 
     log_info("Checking bel names..\n");
     for (BelId bel : ctx->getBels()) {
-        IdString name = ctx->getBelName(bel);
+        IdStringList name = ctx->getBelName(bel);
         BelId bel2 = ctx->getBelByName(name);
         if (bel != bel2) {
-            log_error("bel != bel2, name = %s\n", name.c_str(ctx));
+            log_error("bel != bel2, name = %s\n", ctx->nameOfBel(bel));
         }
     }
 

common/nextpnr.cc

@@ -111,6 +111,14 @@ TimingConstrObjectId BaseCtx::timingWildcardObject()
     return id;
 }
 
+std::string &StrRingBuffer::next()
+{
+    std::string &s = buffer.at(index++);
+    if (index >= N)
+        index = 0;
+    return s;
+}
+
 TimingConstrObjectId BaseCtx::timingClockDomainObject(NetInfo *clockDomain)
 {
     NPNR_ASSERT(clockDomain->clkconstr != nullptr);
@@ -283,7 +291,9 @@ void BaseCtx::removeConstraint(IdString constrName)
 const char *BaseCtx::nameOfBel(BelId bel) const
 {
     const Context *ctx = getCtx();
-    return ctx->getBelName(bel).c_str(ctx);
+    std::string &s = ctx->log_strs.next();
+    ctx->getBelName(bel).build_str(ctx, s);
+    return s.c_str();
 }
 
 const char *BaseCtx::nameOfWire(WireId wire) const
@@ -304,6 +314,12 @@ const char *BaseCtx::nameOfGroup(GroupId group) const
     return ctx->getGroupName(group).c_str(ctx);
 }
 
+BelId BaseCtx::getBelByNameStr(const std::string &str)
+{
+    Context *ctx = getCtx();
+    return ctx->getBelByName(IdStringList::parse(ctx, str));
+}
+
 WireId Context::getNetinfoSourceWire(const NetInfo *net_info) const
 {
     if (net_info->driver.cell == nullptr)
@@ -655,7 +671,7 @@ void BaseCtx::archInfoToAttributes()
             if (ci->attrs.find(id("BEL")) != ci->attrs.end()) {
                 ci->attrs.erase(ci->attrs.find(id("BEL")));
             }
-            ci->attrs[id("NEXTPNR_BEL")] = getCtx()->getBelName(ci->bel).str(this);
+            ci->attrs[id("NEXTPNR_BEL")] = getCtx()->getBelName(ci->bel).str(getCtx());
             ci->attrs[id("BEL_STRENGTH")] = (int)ci->belStrength;
         }
         if (ci->constr_x != ci->UNCONSTR)
@@ -707,7 +723,7 @@ void BaseCtx::attributesToArchInfo()
             if (str != ci->attrs.end())
                 strength = (PlaceStrength)str->second.as_int64();
 
-            BelId b = getCtx()->getBelByName(id(val->second.as_string()));
+            BelId b = getCtx()->getBelByNameStr(val->second.as_string());
             getCtx()->bindBel(b, ci, strength);
         }
 

common/nextpnr.h

@@ -148,14 +148,13 @@ NEXTPNR_NAMESPACE_BEGIN
 // An small size optimised array that is statically allocated when the size is N or less; heap allocated otherwise
 template <typename T, size_t N> class SSOArray
 {
+  private:
     union
     {
         T data_static[N];
         T *data_heap;
     };
     size_t m_size;
-
-  private:
     inline bool is_heap() const { return (m_size > N); }
     void alloc()
     {
@@ -224,8 +223,8 @@ struct IdStringList
     SSOArray<IdString, 4> ids;
 
     IdStringList(){};
-    explicit IdStringList(size_t n) : ids(n, IdString()){};
+    IdStringList(size_t n) : ids(n, IdString()){};
-    explicit IdStringList(IdString id) : ids(1, id){};
+    IdStringList(IdString id) : ids(1, id){};
     template <typename Tlist> IdStringList(const Tlist &list) : ids(list){};
 
     static IdStringList parse(Context *ctx, const std::string &str);
@@ -238,6 +237,19 @@ struct IdStringList
     const IdString &operator[](size_t idx) const { return ids[idx]; }
 };
 
+// A ring buffer of strings, so we can return a simple const char * pointer for %s formatting - inspired by how logging
+// in Yosys works Let's just hope noone tries to log more than 100 things in one call....
+class StrRingBuffer
+{
+  private:
+    static const size_t N = 100;
+    std::array<std::string, N> buffer;
+    size_t index = 0;
+
+  public:
+    std::string &next();
+};
+
 struct GraphicElement
 {
     enum type_t
@@ -760,6 +772,9 @@ struct BaseCtx
     mutable std::unordered_map<std::string, int> *idstring_str_to_idx;
     mutable std::vector<const std::string *> *idstring_idx_to_str;
 
+    // Temporary string backing store for logging
+    mutable StrRingBuffer log_strs;
+
     // Project settings and config switches
     std::unordered_map<IdString, Property> settings;
 
@@ -875,6 +890,9 @@ struct BaseCtx
     const char *nameOfPip(PipId pip) const;
     const char *nameOfGroup(GroupId group) const;
 
+    // Overrides of arch functions that take a string and handle IdStringList parsing
+    BelId getBelByNameStr(const std::string &str);
+
     // --------------------------------------------------------------
 
     bool allUiReload = true;

common/place_common.cc

@@ -158,8 +158,7 @@ bool place_single_cell(Context *ctx, CellInfo *cell, bool require_legality)
             all_placed = true;
         }
         if (ctx->verbose)
-            log_info("   placed single cell '%s' at '%s'\n", cell->name.c_str(ctx),
+            log_info("   placed single cell '%s' at '%s'\n", cell->name.c_str(ctx), ctx->nameOfBel(best_bel));
-                     ctx->getBelName(best_bel).c_str(ctx));
         ctx->bindBel(best_bel, cell, STRENGTH_WEAK);
 
         cell = ripup_target;
@@ -375,7 +374,7 @@ class ConstraintLegaliseWorker
                             if (confl_cell != nullptr) {
                                 if (ctx->verbose)
                                     log_info("       '%s' already placed at '%s'\n", ctx->nameOf(confl_cell),
-                                             ctx->getBelName(confl_cell->bel).c_str(ctx));
+                                             ctx->nameOfBel(confl_cell->bel));
                                 NPNR_ASSERT(confl_cell->belStrength < STRENGTH_STRONG);
                                 ctx->unbindBel(target);
                                 rippedCells.insert(confl_cell->name);
@@ -489,7 +488,7 @@ class ConstraintLegaliseWorker
         for (auto cell : sorted(ctx->cells))
             if (get_constraints_distance(ctx, cell.second) != 0)
                 log_error("constraint satisfaction check failed for cell '%s' at Bel '%s'\n", cell.first.c_str(ctx),
-                          ctx->getBelName(cell.second->bel).c_str(ctx));
+                          ctx->nameOfBel(cell.second->bel));
         return score;
     }
 };

common/placer1.cc

@@ -154,7 +154,7 @@ class SAPlacer
                 auto loc = cell->attrs.find(ctx->id("BEL"));
                 if (loc != cell->attrs.end()) {
                     std::string loc_name = loc->second.as_string();
-                    BelId bel = ctx->getBelByName(ctx->id(loc_name));
+                    BelId bel = ctx->getBelByNameStr(loc_name);
                     if (bel == BelId()) {
                         log_error("No Bel named \'%s\' located for "
                                   "this chip (processing BEL attribute on \'%s\')\n",
@@ -409,18 +409,18 @@ class SAPlacer
                 if (ctx->force) {
                     log_warning("post-placement validity check failed for Bel '%s' "
                                 "(%s)\n",
-                                ctx->getBelName(bel).c_str(ctx), cell_text.c_str());
+                                ctx->nameOfBel(bel), cell_text.c_str());
                 } else {
                     log_error("post-placement validity check failed for Bel '%s' "
                               "(%s)\n",
-                              ctx->getBelName(bel).c_str(ctx), cell_text.c_str());
+                              ctx->nameOfBel(bel), cell_text.c_str());
                 }
             }
         }
         for (auto cell : sorted(ctx->cells))
             if (get_constraints_distance(ctx, cell.second) != 0)
                 log_error("constraint satisfaction check failed for cell '%s' at Bel '%s'\n", cell.first.c_str(ctx),
-                          ctx->getBelName(cell.second->bel).c_str(ctx));
+                          ctx->nameOfBel(cell.second->bel));
         timing_analysis(ctx);
         ctx->unlock();
         return true;

common/placer_heap.cc

@@ -305,7 +305,7 @@ class HeAPPlacer
             if (ctx->getBoundBelCell(cell.second->bel) != cell.second)
                 log_error("Found cell %s with mismatched binding\n", cell.first.c_str(ctx));
             if (ctx->debug)
-                log_info("AP soln: %s -> %s\n", cell.first.c_str(ctx), ctx->getBelName(cell.second->bel).c_str(ctx));
+                log_info("AP soln: %s -> %s\n", cell.first.c_str(ctx), ctx->nameOfBel(cell.second->bel));
         }
 
         ctx->unlock();
@@ -379,7 +379,7 @@ class HeAPPlacer
             auto loc = cell->attrs.find(ctx->id("BEL"));
             if (loc != cell->attrs.end()) {
                 std::string loc_name = loc->second.as_string();
-                BelId bel = ctx->getBelByName(ctx->id(loc_name));
+                BelId bel = ctx->getBelByNameStr(loc_name);
                 if (bel == BelId()) {
                     log_error("No Bel named \'%s\' located for "
                               "this chip (processing BEL attribute on \'%s\')\n",

common/timing_opt.cc

@@ -427,7 +427,7 @@ class TimingOptimiser
                         if (pn->users.at(i).cell == port->cell && pn->users.at(i).port == port->port)
                             crit = net_crit.at(pn->name).criticality.at(i);
                 log_info("    %s.%s at %s crit %0.02f\n", port->cell->name.c_str(ctx), port->port.c_str(ctx),
-                         ctx->getBelName(port->cell->bel).c_str(ctx), crit);
+                         ctx->nameOfBel(port->cell->bel), crit);
             }
             if (std::find(path_cells.begin(), path_cells.end(), port->cell->name) != path_cells.end())
                 continue;
@@ -472,10 +472,9 @@ class TimingOptimiser
 
         if (ctx->debug) {
             for (auto cell : path_cells) {
-                log_info("Candidate neighbours for %s (%s):\n", cell.c_str(ctx),
+                log_info("Candidate neighbours for %s (%s):\n", cell.c_str(ctx), ctx->nameOfBel(ctx->cells[cell]->bel));
-                         ctx->getBelName(ctx->cells[cell]->bel).c_str(ctx));
                 for (auto neigh : cell_neighbour_bels.at(cell)) {
-                    log_info("    %s\n", ctx->getBelName(neigh).c_str(ctx));
+                    log_info("    %s\n", ctx->nameOfBel(neigh));
                 }
             }
         }
@@ -597,7 +596,7 @@ class TimingOptimiser
                 CellInfo *cell = ctx->cells.at(rt_entry.first).get();
                 cell_swap_bel(cell, rt_entry.second);
                 if (ctx->debug)
-                    log_info("    %s at %s\n", rt_entry.first.c_str(ctx), ctx->getBelName(rt_entry.second).c_str(ctx));
+                    log_info("    %s at %s\n", rt_entry.first.c_str(ctx), ctx->nameOfBel(rt_entry.second));
             }
 
         } else {

ecp5/arch.cc

@@ -128,6 +128,11 @@ Arch::Arch(ArchArgs args) : args(args)
         bucket.name = bel_type;
         buckets.push_back(bucket);
     }
+
+    for (int i = 0; i < chip_info->width; i++)
+        x_ids.push_back(id(stringf("X%d", i)));
+    for (int i = 0; i < chip_info->height; i++)
+        y_ids.push_back(id(stringf("Y%d", i)));
 }
 
 // -----------------------------------------------------------------------
@@ -208,16 +213,18 @@ IdString Arch::archArgsToId(ArchArgs args) const
 
 // -----------------------------------------------------------------------
 
-BelId Arch::getBelByName(IdString name) const
+BelId Arch::getBelByName(IdStringList name) const
 {
+    // TODO: take advantage of IdStringList for fast parsing
     BelId ret;
+#if 0
     auto it = bel_by_name.find(name);
     if (it != bel_by_name.end())
         return it->second;
-
+#endif
     Location loc;
     std::string basename;
-    std::tie(loc.x, loc.y, basename) = split_identifier_name(name.str(this));
+    std::tie(loc.x, loc.y, basename) = split_identifier_name(name.str(getCtx()));
     ret.location = loc;
     const LocationTypePOD *loci = locInfo(ret);
     for (int i = 0; i < int(loci->bel_data.size()); i++) {
@@ -226,8 +233,10 @@ BelId Arch::getBelByName(IdString name) const
             break;
         }
     }
+#if 0
     if (ret.index >= 0)
         bel_by_name[name] = ret;
+#endif
     return ret;
 }
 

ecp5/arch.h

@@ -450,6 +450,9 @@ struct Arch : BaseCtx
     std::unordered_map<PipId, NetInfo *> pip_to_net;
     std::unordered_map<WireId, int> wire_fanout;
 
+    // fast access to  X and Y IdStrings for building object names
+    std::vector<IdString> x_ids, y_ids;
+
     ArchArgs args;
     Arch(ArchArgs args);
 
@@ -475,19 +478,19 @@ struct Arch : BaseCtx
 
     // -------------------------------------------------
 
-    BelId getBelByName(IdString name) const;
+    BelId getBelByName(IdStringList name) const;
 
     template <typename Id> const LocationTypePOD *locInfo(Id &id) const
     {
         return &(chip_info->locations[chip_info->location_type[id.location.y * chip_info->width + id.location.x]]);
     }
 
-    IdString getBelName(BelId bel) const
+    IdStringList getBelName(BelId bel) const
     {
         NPNR_ASSERT(bel != BelId());
-        std::stringstream name;
+        std::array<IdString, 3> ids{x_ids.at(bel.location.x), y_ids.at(bel.location.y),
-        name << "X" << bel.location.x << "/Y" << bel.location.y << "/" << locInfo(bel)->bel_data[bel.index].name.get();
+                                    id(locInfo(bel)->bel_data[bel.index].name.get())};
-        return id(name.str());
+        return IdStringList(ids);
     }
 
     uint32_t getBelChecksum(BelId bel) const { return bel.index; }

ecp5/arch_pybindings.h

@@ -30,7 +30,7 @@ namespace PythonConversion {
 
 template <> struct string_converter<BelId>
 {
-    BelId from_str(Context *ctx, std::string name) { return ctx->getBelByName(ctx->id(name)); }
+    BelId from_str(Context *ctx, std::string name) { return ctx->getBelByNameStr(name); }
 
     std::string to_str(Context *ctx, BelId id)
     {

ecp5/globals.cc

@@ -176,8 +176,8 @@ class Ecp5GlobalRouter
                 }
             }
             if (upstream.size() > 30000) {
-                log_error("failed to route HPBX%02d00 to %s.%s\n", global_index,
+                log_error("failed to route HPBX%02d00 to %s.%s\n", global_index, ctx->nameOfBel(user.cell->bel),
-                          ctx->getBelName(user.cell->bel).c_str(ctx), user.port.c_str(ctx));
+                          user.port.c_str(ctx));
             }
         }
         // Set all the pips we found along the way
@@ -300,7 +300,7 @@ class Ecp5GlobalRouter
         if (drv.cell == nullptr) {
             return 0;
         } else if (drv.cell->attrs.count(ctx->id("BEL"))) {
-            drv_bel = ctx->getBelByName(ctx->id(drv.cell->attrs.at(ctx->id("BEL")).as_string()));
+            drv_bel = ctx->getBelByNameStr(drv.cell->attrs.at(ctx->id("BEL")).as_string());
         } else {
             // Check if driver is a singleton
             BelId last_bel;

ecp5/pack.cc

@@ -522,7 +522,7 @@ class Ecp5Packer
                                       trio->name.c_str(ctx), pin.c_str(), ctx->args.package.c_str());
                         } else {
                             log_info("pin '%s' constrained to Bel '%s'.\n", trio->name.c_str(ctx),
-                                     ctx->getBelName(pinBel).c_str(ctx));
+                                     ctx->nameOfBel(pinBel));
                         }
                         trio->attrs[ctx->id("BEL")] = ctx->getBelName(pinBel).str(ctx);
                     }
@@ -1657,7 +1657,7 @@ class Ecp5Packer
                     CellInfo *dcu = clki->driver.cell;
                     if (!dcu->attrs.count(ctx->id("BEL")))
                         log_error("DCU must be constrained to a Bel!\n");
-                    BelId bel = ctx->getBelByName(ctx->id(dcu->attrs.at(ctx->id("BEL")).as_string()));
+                    BelId bel = ctx->getBelByNameStr(dcu->attrs.at(ctx->id("BEL")).as_string());
                     if (bel == BelId())
                         log_error("Invalid DCU bel '%s'\n", dcu->attrs.at(ctx->id("BEL")).c_str());
                     Loc loc = ctx->getBelLocation(bel);
@@ -1704,7 +1704,7 @@ class Ecp5Packer
         for (auto cell : sorted(ctx->cells)) {
             CellInfo *ci = cell.second;
             if (ci->type == id_EHXPLLL && ci->attrs.count(ctx->id("BEL")))
-                available_plls.erase(ctx->getBelByName(ctx->id(ci->attrs.at(ctx->id("BEL")).as_string())));
+                available_plls.erase(ctx->getBelByNameStr(ci->attrs.at(ctx->id("BEL")).as_string()));
         }
         // Place PLL connected to fixed drivers such as IO close to their source
         for (auto cell : sorted(ctx->cells)) {
@@ -1716,7 +1716,7 @@ class Ecp5Packer
                 const CellInfo *drivercell = drivernet->driver.cell;
                 if (!drivercell->attrs.count(ctx->id("BEL")))
                     continue;
-                BelId drvbel = ctx->getBelByName(ctx->id(drivercell->attrs.at(ctx->id("BEL")).as_string()));
+                BelId drvbel = ctx->getBelByNameStr(drivercell->attrs.at(ctx->id("BEL")).as_string());
                 Loc drvloc = ctx->getBelLocation(drvbel);
                 BelId closest_pll;
                 int closest_distance = std::numeric_limits<int>::max();
@@ -1848,8 +1848,8 @@ class Ecp5Packer
         WireId next;
         while (true) {
             if (upstream.empty() || upstream.size() > 30000)
-                log_error("failed to route bank %d ECLK%d to %s.%s\n", bank, found_eclk,
+                log_error("failed to route bank %d ECLK%d to %s.%s\n", bank, found_eclk, ctx->nameOfBel(usr_bel),
-                          ctx->getBelName(usr_bel).c_str(ctx), usr_port.name.c_str(ctx));
+                          usr_port.name.c_str(ctx));
             next = upstream.front();
             upstream.pop();
             if (ctx->debug)
@@ -1913,17 +1913,17 @@ class Ecp5Packer
                     log_error("DQSBUFM can only be used with a pin-constrained PIO connected to its DQSI input"
                               "(while processing '%s').\n",
                               ci->name.c_str(ctx));
-                BelId pio_bel = ctx->getBelByName(ctx->id(pio->attrs.at(ctx->id("BEL")).as_string()));
+                BelId pio_bel = ctx->getBelByNameStr(pio->attrs.at(ctx->id("BEL")).as_string());
                 NPNR_ASSERT(pio_bel != BelId());
                 Loc pio_loc = ctx->getBelLocation(pio_bel);
                 if (pio_loc.z != 0)
                     log_error("PIO '%s' does not appear to be a DQS site (expecting an 'A' pin).\n",
-                              ctx->getBelName(pio_bel).c_str(ctx));
+                              ctx->nameOfBel(pio_bel));
                 pio_loc.z = 8;
                 BelId dqsbuf = ctx->getBelByLocation(pio_loc);
                 if (dqsbuf == BelId() || ctx->getBelType(dqsbuf) != id_DQSBUFM)
                     log_error("PIO '%s' does not appear to be a DQS site (didn't find a DQSBUFM).\n",
-                              ctx->getBelName(pio_bel).c_str(ctx));
+                              ctx->nameOfBel(pio_bel));
                 ci->attrs[ctx->id("BEL")] = ctx->getBelName(dqsbuf).str(ctx);
                 bool got_dqsg = ctx->getPIODQSGroup(pio_bel, dqsbuf_dqsg[ci->name].first, dqsbuf_dqsg[ci->name].second);
                 NPNR_ASSERT(got_dqsg);
@@ -2078,15 +2078,14 @@ class Ecp5Packer
                 log_error("IOLOGIC functionality (DDR, DELAY, DQS, etc) can only be used with pin-constrained PIO "
                           "(while processing '%s').\n",
                           curr->name.c_str(ctx));
-            BelId bel = ctx->getBelByName(ctx->id(pio->attrs.at(ctx->id("BEL")).as_string()));
+            BelId bel = ctx->getBelByNameStr(pio->attrs.at(ctx->id("BEL")).as_string());
             NPNR_ASSERT(bel != BelId());
             return bel;
         };
 
         auto create_pio_iologic = [&](CellInfo *pio, CellInfo *curr) {
             BelId bel = get_pio_bel(pio, curr);
-            log_info("IOLOGIC component %s connected to PIO Bel %s\n", curr->name.c_str(ctx),
+            log_info("IOLOGIC component %s connected to PIO Bel %s\n", curr->name.c_str(ctx), ctx->nameOfBel(bel));
-                     ctx->getBelName(bel).c_str(ctx));
             Loc loc = ctx->getBelLocation(bel);
             bool s = false;
             if (loc.y == 0 || loc.y == (ctx->chip_info->height - 1))
@@ -2292,8 +2291,7 @@ class Ecp5Packer
                 replace_port(ci, ctx->id("D2"), iol, id_TXDATA2);
                 replace_port(ci, ctx->id("D3"), iol, id_TXDATA3);
                 if (ci->type == ctx->id("ODDR71B")) {
-                    Loc loc =
+                    Loc loc = ctx->getBelLocation(ctx->getBelByNameStr(pio->attrs.at(ctx->id("BEL")).as_string()));
-                            ctx->getBelLocation(ctx->getBelByName(ctx->id(pio->attrs.at(ctx->id("BEL")).as_string())));
                     if (loc.z % 2 == 1)
                         log_error("ODDR71B '%s' can only be used at 'A' or 'C' locations\n", ci->name.c_str(ctx));
                     replace_port(ci, ctx->id("D4"), iol, id_TXDATA4);
@@ -2326,8 +2324,7 @@ class Ecp5Packer
                 replace_port(ci, ctx->id("Q2"), iol, id_RXDATA2);
                 replace_port(ci, ctx->id("Q3"), iol, id_RXDATA3);
                 if (ci->type == ctx->id("IDDR71B")) {
-                    Loc loc =
+                    Loc loc = ctx->getBelLocation(ctx->getBelByNameStr(pio->attrs.at(ctx->id("BEL")).as_string()));
-                            ctx->getBelLocation(ctx->getBelByName(ctx->id(pio->attrs.at(ctx->id("BEL")).as_string())));
                     if (loc.z % 2 == 1)
                         log_error("IDDR71B '%s' can only be used at 'A' or 'C' locations\n", ci->name.c_str(ctx));
                     replace_port(ci, ctx->id("Q4"), iol, id_RXDATA4);
@@ -2579,7 +2576,7 @@ class Ecp5Packer
                         if (!user.cell->attrs.count(ctx->id("BEL")))
                             continue;
                         Loc user_loc = ctx->getBelLocation(
-                                ctx->getBelByName(ctx->id(user.cell->attrs.at(ctx->id("BEL")).as_string())));
+                                ctx->getBelByNameStr(user.cell->attrs.at(ctx->id("BEL")).as_string()));
                         for (auto bel : ctx->getBels()) {
                             if (ctx->getBelType(bel) != id_ECLKBRIDGECS)
                                 continue;
@@ -2594,8 +2591,8 @@ class Ecp5Packer
                         CellInfo *drv = input->driver.cell;
                         if (!drv->attrs.count(ctx->id("BEL")))
                             continue;
-                        Loc drv_loc = ctx->getBelLocation(
+                        Loc drv_loc =
-                                ctx->getBelByName(ctx->id(drv->attrs.at(ctx->id("BEL")).as_string())));
+                                ctx->getBelLocation(ctx->getBelByNameStr(drv->attrs.at(ctx->id("BEL")).as_string()));
                         BelId closest;
                         int closest_x = -1; // aim for same side of chip
                         for (auto bel : ctx->getBels()) {
@@ -2639,7 +2636,7 @@ class Ecp5Packer
             if (ci->type == id_IOLOGIC || ci->type == id_DQSBUFM) {
                 if (!ci->ports.count(id_ECLK) || ci->ports.at(id_ECLK).net == nullptr)
                     continue;
-                BelId bel = ctx->getBelByName(ctx->id(str_or_default(ci->attrs, ctx->id("BEL"))));
+                BelId bel = ctx->getBelByNameStr(str_or_default(ci->attrs, ctx->id("BEL")));
                 NPNR_ASSERT(bel != BelId());
                 Loc pioLoc = ctx->getBelLocation(bel);
                 if (ci->type == id_DQSBUFM)
@@ -2683,8 +2680,7 @@ class Ecp5Packer
                 const NetInfo *eclko = net_or_nullptr(ci, id_ECLKO);
                 if (eclki != nullptr && eclki->driver.cell != nullptr) {
                     if (eclki->driver.cell->type == id_ECLKBRIDGECS) {
-                        BelId bel =
+                        BelId bel = ctx->getBelByNameStr(eclki->driver.cell->attrs.at(ctx->id("BEL")).as_string());
-                                ctx->getBelByName(ctx->id(eclki->driver.cell->attrs.at(ctx->id("BEL")).as_string()));
                         Loc loc = ctx->getBelLocation(bel);
                         ci->attrs[ctx->id("BEL")] =
                                 ctx->getBelName(ctx->getBelByLocation(Loc(loc.x, loc.y, 15))).str(ctx);
@@ -2697,7 +2693,7 @@ class Ecp5Packer
                 for (auto user : eclko->users) {
                     if (user.cell->type == id_TRELLIS_ECLKBUF) {
                         Loc eckbuf_loc = ctx->getBelLocation(
-                                ctx->getBelByName(ctx->id(user.cell->attrs.at(ctx->id("BEL")).as_string())));
+                                ctx->getBelByNameStr(user.cell->attrs.at(ctx->id("BEL")).as_string()));
                         for (auto bel : ctx->getBels()) {
                             if (ctx->getBelType(bel) != id_ECLKSYNCB)
                                 continue;
@@ -2726,7 +2722,7 @@ class Ecp5Packer
                         const CellInfo *uc = usr.cell;
                         if (uc->type != id_DQSBUFM || !uc->attrs.count(ctx->id("BEL")))
                             continue;
-                        BelId dqsb_bel = ctx->getBelByName(ctx->id(uc->attrs.at(ctx->id("BEL")).as_string()));
+                        BelId dqsb_bel = ctx->getBelByNameStr(uc->attrs.at(ctx->id("BEL")).as_string());
                         Loc dqsb_loc = ctx->getBelLocation(dqsb_bel);
                         if (dqsb_loc.x > 15)
                             right_bank_users = true;
@@ -2809,7 +2805,7 @@ class Ecp5Packer
                 CellInfo *drv = clki->driver.cell;
                 if (drv->type != id_ECLKSYNCB || !drv->attrs.count(ctx->id("BEL")))
                     continue;
-                BelId bel = ctx->getBelByName(ctx->id(drv->attrs.at(ctx->id("BEL")).as_string()));
+                BelId bel = ctx->getBelByNameStr(drv->attrs.at(ctx->id("BEL")).as_string());
                 // Find a CLKDIVF that is routeable from the ECLKSYNC
                 std::queue<WireId> visit;
                 visit.push(ctx->getBelPinWire(bel, id_ECLKO));