diff --git a/ice40/arch_place.cc b/ice40/arch_place.cc
index 25044525..60fa928e 100644
--- a/ice40/arch_place.cc
+++ b/ice40/arch_place.cc
@@ -139,8 +139,8 @@ bool PlaceValidityChecker::isValidBelForCell(CellInfo *cell, BelId bel)
         return ctx->getBelPackagePin(bel) != "";
     } else if (cell->type == id_sb_gb) {
         bool is_reset = false, is_cen = false;
-        assert(cell->ports.at("GLOBAL_BUFFER_OUTPUT").net != nullptr);
-        for (auto user : cell->ports.at("GLOBAL_BUFFER_OUTPUT").net->users) {
+        assert(cell->ports.at(ctx->id("GLOBAL_BUFFER_OUTPUT")).net != nullptr);
+        for (auto user : cell->ports.at(ctx->id("GLOBAL_BUFFER_OUTPUT")).net->users) {
             if (is_reset_port(ctx, user))
                 is_reset = true;
             if (is_enable_port(ctx, user))
@@ -148,7 +148,7 @@ bool PlaceValidityChecker::isValidBelForCell(CellInfo *cell, BelId bel)
         }
         IdString glb_net = ctx->getWireName(
                 ctx->getWireBelPin(bel, PIN_GLOBAL_BUFFER_OUTPUT));
-        int glb_id = std::stoi(std::string("") + glb_net.str().back());
+        int glb_id = std::stoi(std::string("") + glb_net.str(ctx).back());
         if (is_reset && is_cen)
             return false;
         else if (is_reset)
diff --git a/ice40/bitstream.cc b/ice40/bitstream.cc
index 8e34335c..61bbe27d 100644
--- a/ice40/bitstream.cc
+++ b/ice40/bitstream.cc
@@ -441,7 +441,7 @@ void write_asc(const Context *ctx, std::ostream &out)
                             cell.second,
                             ctx->id(std::string("INIT_") + get_hexdigit(w)));
                     assert(init != "");
-                    for (int i = 0; i < init.size(); i++) {
+                    for (size_t i = 0; i < init.size(); i++) {
                         bool val = (init.at((init.size() - 1) - i) == '1');
                         bits.at(i) = val;
                     }
@@ -458,7 +458,7 @@ void write_asc(const Context *ctx, std::ostream &out)
     }
 
     // Write symbols
-    const bool write_symbols = 1;
+    //const bool write_symbols = 1;
     for (auto wire : ctx->getWires()) {
         IdString net = ctx->getWireNet(wire, false);
         if (net != IdString())
diff --git a/ice40/cells.cc b/ice40/cells.cc
index 0ae25e12..056c33f8 100644
--- a/ice40/cells.cc
+++ b/ice40/cells.cc
@@ -36,7 +36,7 @@ CellInfo *create_ice_cell(Context *ctx, IdString type, std::string name)
     static int auto_idx = 0;
     CellInfo *new_cell = new CellInfo();
     if (name.empty()) {
-        new_cell->name = IdString(ctx, "$nextpnr_" + type.str() + "_" +
+        new_cell->name = ctx->id( "$nextpnr_" + type.str(ctx) + "_" +
                                                std::to_string(auto_idx++));
     } else {
         new_cell->name = ctx->id(name);
@@ -132,13 +132,13 @@ CellInfo *create_ice_cell(Context *ctx, IdString type, std::string name)
 
 void lut_to_lc(const Context *ctx, CellInfo *lut, CellInfo *lc, bool no_dff)
 {
-    lc->params["LUT_INIT"] = lut->params["LUT_INIT"];
-    replace_port(lut, "I0", lc, "I0");
-    replace_port(lut, "I1", lc, "I1");
-    replace_port(lut, "I2", lc, "I2");
-    replace_port(lut, "I3", lc, "I3");
+    lc->params[ctx->id("LUT_INIT")] = lut->params[ctx->id("LUT_INIT")];
+    replace_port(lut, ctx->id("I0"), lc, ctx->id("I0"));
+    replace_port(lut, ctx->id("I1"), lc, ctx->id("I1"));
+    replace_port(lut, ctx->id("I2"), lc, ctx->id("I2"));
+    replace_port(lut, ctx->id("I3"), lc, ctx->id("I3"));
     if (no_dff) {
-        replace_port(lut, "O", lc, "O");
+        replace_port(lut, ctx->id("O"), lc, ctx->id("O"));
         lc->params[ctx->id("DFF_ENABLE")] = "0";
     }
 }
@@ -149,7 +149,7 @@ void dff_to_lc(const Context *ctx, CellInfo *dff, CellInfo *lc,
     lc->params[ctx->id("DFF_ENABLE")] = "1";
     std::string config = dff->type.str(ctx).substr(6);
     auto citer = config.begin();
-    replace_port(dff, "C", lc, "CLK");
+    replace_port(dff, ctx->id("C"), lc, ctx->id("CLK"));
 
     if (citer != config.end() && *citer == 'N') {
         lc->params[ctx->id("NEG_CLK")] = "1";
@@ -159,7 +159,7 @@ void dff_to_lc(const Context *ctx, CellInfo *dff, CellInfo *lc,
     }
 
     if (citer != config.end() && *citer == 'E') {
-        replace_port(dff, "E", lc, "CEN");
+        replace_port(dff, ctx->id("E"), lc, ctx->id("CEN"));
         ++citer;
     }
 
@@ -174,12 +174,12 @@ void dff_to_lc(const Context *ctx, CellInfo *dff, CellInfo *lc,
 
         if (*citer == 'S') {
             citer++;
-            replace_port(dff, "S", lc, "SR");
+            replace_port(dff, ctx->id("S"), lc, ctx->id("SR"));
             lc->params[ctx->id("SET_NORESET")] = "1";
         } else {
             assert(*citer == 'R');
             citer++;
-            replace_port(dff, "R", lc, "SR");
+            replace_port(dff, ctx->id("R"), lc, ctx->id("SR"));
             lc->params[ctx->id("SET_NORESET")] = "0";
         }
     }
@@ -188,28 +188,28 @@ void dff_to_lc(const Context *ctx, CellInfo *dff, CellInfo *lc,
 
     if (pass_thru_lut) {
         lc->params[ctx->id("LUT_INIT")] = "2";
-        replace_port(dff, "D", lc, "I0");
+        replace_port(dff, ctx->id("D"), lc, ctx->id("I0"));
     }
 
-    replace_port(dff, "Q", lc, "O");
+    replace_port(dff, ctx->id("Q"), lc, ctx->id("O"));
 }
 
 void nxio_to_sb(Context *ctx, CellInfo *nxio, CellInfo *sbio)
 {
     if (nxio->type == ctx->id("$nextpnr_ibuf")) {
         sbio->params[ctx->id("PIN_TYPE")] = "1";
-        auto pu_attr = nxio->attrs.find("PULLUP");
+        auto pu_attr = nxio->attrs.find(ctx->id("PULLUP"));
         if (pu_attr != nxio->attrs.end())
             sbio->params[ctx->id("PULLUP")] = pu_attr->second;
-        replace_port(nxio, "O", sbio, "D_IN_0");
+        replace_port(nxio, ctx->id("O"), sbio, ctx->id("D_IN_0"));
     } else if (nxio->type == ctx->id("$nextpnr_obuf")) {
         sbio->params[ctx->id("PIN_TYPE")] = "25";
-        replace_port(nxio, "I", sbio, "D_OUT_0");
+        replace_port(nxio, ctx->id("I"), sbio, ctx->id("D_OUT_0"));
     } else if (nxio->type == ctx->id("$nextpnr_iobuf")) {
         // N.B. tristate will be dealt with below
         sbio->params[ctx->id("PIN_TYPE")] = "25";
-        replace_port(nxio, "I", sbio, "D_OUT_0");
-        replace_port(nxio, "O", sbio, "D_IN_0");
+        replace_port(nxio, ctx->id("I"), sbio, ctx->id("D_OUT_0"));
+        replace_port(nxio, ctx->id("O"), sbio, ctx->id("D_IN_0"));
     } else {
         assert(false);
     }
@@ -219,11 +219,11 @@ void nxio_to_sb(Context *ctx, CellInfo *nxio, CellInfo *sbio)
                           [](const Context *ctx, const CellInfo *cell) {
                               return cell->type == ctx->id("$_TBUF_");
                           },
-                          "Y");
+                          ctx->id("Y"));
     if (tbuf) {
         sbio->params[ctx->id("PIN_TYPE")] = "41";
-        replace_port(tbuf, "A", sbio, "D_OUT_0");
-        replace_port(tbuf, "E", sbio, "OUTPUT_ENABLE");
+        replace_port(tbuf, ctx->id("A"), sbio, ctx->id("D_OUT_0"));
+        replace_port(tbuf, ctx->id("E"), sbio, ctx->id("OUTPUT_ENABLE"));
         ctx->nets.erase(donet->name);
         if (!donet->users.empty())
             log_error(
diff --git a/ice40/pack.cc b/ice40/pack.cc
index 5022fc59..868b0fd8 100644
--- a/ice40/pack.cc
+++ b/ice40/pack.cc
@@ -41,7 +41,7 @@ static void pack_lut_lutffs(Context *ctx)
             log_info("cell '%s' is of type '%s'\n", ci->name.c_str(ctx),
                      ci->type.c_str(ctx));
         if (is_lut(ctx, ci)) {
-            CellInfo *packed = create_ice_cell(ctx, "ICESTORM_LC",
+            CellInfo *packed = create_ice_cell(ctx, ctx->id("ICESTORM_LC"),
                                                ci->name.str(ctx) + "_LC");
             std::copy(ci->attrs.begin(), ci->attrs.end(),
                       std::inserter(packed->attrs, packed->attrs.begin()));
@@ -53,7 +53,7 @@ static void pack_lut_lutffs(Context *ctx)
             // See if we can pack into a DFF
             // TODO: LUT cascade
             NetInfo *o = ci->ports.at(ctx->id("O")).net;
-            CellInfo *dff = net_only_drives(ctx, o, is_ff, "D", true);
+            CellInfo *dff = net_only_drives(ctx, o, is_ff, ctx->id("D"), true);
             auto lut_bel = ci->attrs.find(ctx->id("BEL"));
             bool packed_dff = false;
             if (dff) {
@@ -100,7 +100,7 @@ static void pack_nonlut_ffs(Context *ctx)
     for (auto cell : sorted(ctx->cells)) {
         CellInfo *ci = cell.second;
         if (is_ff(ctx, ci)) {
-            CellInfo *packed = create_ice_cell(ctx, "ICESTORM_LC",
+            CellInfo *packed = create_ice_cell(ctx, ctx->id("ICESTORM_LC"),
                                                ci->name.str(ctx) + "_DFFLC");
             std::copy(ci->attrs.begin(), ci->attrs.end(),
                       std::inserter(packed->attrs, packed->attrs.begin()));
@@ -131,18 +131,18 @@ static void pack_carries(Context *ctx)
         CellInfo *ci = cell.second;
         if (is_carry(ctx, ci)) {
             packed_cells.insert(cell.first);
-            CellInfo *carry_ci_lc = net_only_drives(ctx, ci->ports.at("CI").net,
-                                                    is_lc, "I3", false);
-            if (!ci->ports.at("I0").net)
+            CellInfo *carry_ci_lc = net_only_drives(ctx, ci->ports.at(ctx->id("CI")).net,
+                                                    is_lc, ctx->id("I3"), false);
+            if (!ci->ports.at(ctx->id("I0")).net)
                 log_error("SB_CARRY '%s' has disconnected port I0\n",
                           cell.first.c_str(ctx));
-            if (!ci->ports.at("I1").net)
+            if (!ci->ports.at(ctx->id("I1")).net)
                 log_error("SB_CARRY '%s' has disconnected port I1\n",
                           cell.first.c_str(ctx));
 
             std::unordered_set<IdString> i0_matches, i1_matches;
-            auto &i0_usrs = ci->ports.at("I0").net->users;
-            auto &i1_usrs = ci->ports.at("I1").net->users;
+            auto &i0_usrs = ci->ports.at(ctx->id("I0")).net->users;
+            auto &i1_usrs = ci->ports.at(ctx->id("I1")).net->users;
             // Find logic cells connected to both I0 and I1
             for (auto usr : i0_usrs) {
                 if (is_lc(ctx, usr.cell) && usr.port == ctx->id("I1"))
@@ -173,8 +173,8 @@ static void pack_carries(Context *ctx)
                 carry_lc = ctx->cells.at(*carry_lcs.begin());
             }
             carry_lc->attrs[ctx->id("CARRY_ENABLE")] = "1";
-            replace_port(ci, "CI", carry_lc, "CIN");
-            replace_port(ci, "CO", carry_lc, "COUT");
+            replace_port(ci, ctx->id("CI"), carry_lc, ctx->id("CIN"));
+            replace_port(ci, ctx->id("CO"), carry_lc, ctx->id("COUT"));
 
             i0_usrs.erase(std::remove_if(i0_usrs.begin(), i0_usrs.end(),
                                          [ci, ctx](const PortRef &pr) {
@@ -205,29 +205,29 @@ static void pack_ram(Context *ctx)
     for (auto cell : sorted(ctx->cells)) {
         CellInfo *ci = cell.second;
         if (is_ram(ctx, ci)) {
-            CellInfo *packed = create_ice_cell(ctx, "ICESTORM_RAM",
+            CellInfo *packed = create_ice_cell(ctx, ctx->id("ICESTORM_RAM"),
                                                ci->name.str(ctx) + "_RAM");
             packed_cells.insert(ci->name);
             new_cells.push_back(packed);
             for (auto param : ci->params)
                 packed->params[param.first] = param.second;
-            packed->params["NEG_CLK_W"] =
+            packed->params[ctx->id("NEG_CLK_W")] =
                     std::to_string(ci->type == ctx->id("SB_RAM40_4KNW") ||
                                    ci->type == ctx->id("SB_RAM40_4KNRNW"));
-            packed->params["NEG_CLK_R"] =
+            packed->params[ctx->id("NEG_CLK_R")] =
                     std::to_string(ci->type == ctx->id("SB_RAM40_4KNR") ||
                                    ci->type == ctx->id("SB_RAM40_4KNRNW"));
             packed->type = ctx->id("ICESTORM_RAM");
             for (auto port : ci->ports) {
                 PortInfo &pi = port.second;
-                std::string newname = pi.name;
+                std::string newname = pi.name.str(ctx);
                 size_t bpos = newname.find('[');
                 if (bpos != std::string::npos) {
                     newname = newname.substr(0, bpos) + "_" +
                               newname.substr(bpos + 1,
                                              (newname.size() - bpos) - 2);
                 }
-                replace_port(ci, pi.name, packed, newname);
+                replace_port(ci, ctx->id(pi.name.c_str(ctx)), packed, ctx->id(newname));
             }
         }
     }
@@ -268,14 +268,14 @@ static void pack_constants(Context *ctx)
 {
     log_info("Packing constants..\n");
 
-    CellInfo *gnd_cell = create_ice_cell(ctx, "ICESTORM_LC", "$PACKER_GND");
+    CellInfo *gnd_cell = create_ice_cell(ctx, ctx->id("ICESTORM_LC"), "$PACKER_GND");
     gnd_cell->params[ctx->id("LUT_INIT")] = "0";
     NetInfo *gnd_net = new NetInfo;
-    gnd_net->name = "$PACKER_GND_NET";
+    gnd_net->name = ctx->id("$PACKER_GND_NET");
     gnd_net->driver.cell = gnd_cell;
     gnd_net->driver.port = ctx->id("O");
 
-    CellInfo *vcc_cell = create_ice_cell(ctx, "ICESTORM_LC", "$PACKER_VCC");
+    CellInfo *vcc_cell = create_ice_cell(ctx, ctx->id("ICESTORM_LC"), "$PACKER_VCC");
     vcc_cell->params[ctx->id("LUT_INIT")] = "1";
     NetInfo *vcc_net = new NetInfo;
     vcc_net->name = ctx->id("$PACKER_VCC_NET");
@@ -336,12 +336,12 @@ static void pack_io(Context *ctx)
             CellInfo *sb = nullptr;
             if (ci->type == ctx->id("$nextpnr_ibuf") ||
                 ci->type == ctx->id("$nextpnr_iobuf")) {
-                sb = net_only_drives(ctx, ci->ports.at("O").net, is_sb_io,
-                                     "PACKAGE_PIN", true, ci);
+                sb = net_only_drives(ctx, ci->ports.at(ctx->id("O")).net, is_sb_io,
+                                     ctx->id("PACKAGE_PIN"), true, ci);
 
             } else if (ci->type == ctx->id("$nextpnr_obuf")) {
-                sb = net_only_drives(ctx, ci->ports.at("I").net, is_sb_io,
-                                     "PACKAGE_PIN", true, ci);
+                sb = net_only_drives(ctx, ci->ports.at(ctx->id("I")).net, is_sb_io,
+                                     ctx->id("PACKAGE_PIN"), true, ci);
             }
             if (sb != nullptr) {
                 // Trivial case, SB_IO used. Just destroy the net and the
@@ -349,14 +349,14 @@ static void pack_io(Context *ctx)
                 log_info("%s feeds SB_IO %s, removing %s %s.\n",
                          ci->name.c_str(ctx), sb->name.c_str(ctx),
                          ci->type.c_str(ctx), ci->name.c_str(ctx));
-                NetInfo *net = sb->ports.at("PACKAGE_PIN").net;
+                NetInfo *net = sb->ports.at(ctx->id("PACKAGE_PIN")).net;
                 if (net != nullptr) {
                     ctx->nets.erase(net->name);
-                    sb->ports.at("PACKAGE_PIN").net = nullptr;
+                    sb->ports.at(ctx->id("PACKAGE_PIN")).net = nullptr;
                 }
             } else {
                 // Create a SB_IO buffer
-                sb = create_ice_cell(ctx, "SB_IO",
+                sb = create_ice_cell(ctx, ctx->id("SB_IO"),
                                      ci->name.str(ctx) + "$sb_io");
                 nxio_to_sb(ctx, ci, sb);
                 new_cells.push_back(sb);
@@ -379,7 +379,7 @@ static void insert_global(Context *ctx, NetInfo *net, bool is_reset,
 {
     std::string glb_name = net->name.str(ctx) + std::string("_$glb_") +
                            (is_reset ? "sr" : (is_cen ? "ce" : "clk"));
-    CellInfo *gb = create_ice_cell(ctx, "SB_GB", "$gbuf_" + glb_name);
+    CellInfo *gb = create_ice_cell(ctx, ctx->id("SB_GB"), "$gbuf_" + glb_name);
     gb->ports[ctx->id("USER_SIGNAL_TO_GLOBAL_BUFFER")].net = net;
     PortRef pr;
     pr.cell = gb;
@@ -496,16 +496,16 @@ static void pack_intosc(Context *ctx)
     for (auto cell : sorted(ctx->cells)) {
         CellInfo *ci = cell.second;
         if (is_sb_lfosc(ctx, ci)) {
-            CellInfo *packed = create_ice_cell(ctx, "ICESTORM_LFOSC",
+            CellInfo *packed = create_ice_cell(ctx, ctx->id("ICESTORM_LFOSC"),
                                                ci->name.str(ctx) + "_OSC");
             packed_cells.insert(ci->name);
             new_cells.push_back(packed);
-            replace_port(ci, "CLKLFEN", packed, "CLKLFEN");
-            replace_port(ci, "CLKLFPU", packed, "CLKLFPU");
-            if (bool_or_default(ci->attrs, "ROUTE_THROUGH_FABRIC")) {
-                replace_port(ci, "CLKLF", packed, "CLKLF_FABRIC");
+            replace_port(ci, ctx->id("CLKLFEN"), packed, ctx->id("CLKLFEN"));
+            replace_port(ci, ctx->id("CLKLFPU"), packed, ctx->id("CLKLFPU"));
+            if (bool_or_default(ci->attrs, ctx->id("ROUTE_THROUGH_FABRIC"))) {
+                replace_port(ci, ctx->id("CLKLF"), packed, ctx->id("CLKLF_FABRIC"));
             } else {
-                replace_port(ci, "CLKLF", packed, "CLKLF");
+                replace_port(ci, ctx->id("CLKLF"), packed, ctx->id("CLKLF"));
             }
         }
     }
diff --git a/ice40/pcf.cc b/ice40/pcf.cc
index 13fe199e..51f67364 100644
--- a/ice40/pcf.cc
+++ b/ice40/pcf.cc
@@ -52,7 +52,7 @@ bool apply_pcf(Context *ctx, std::istream &in)
                     args_end++;
                 std::string cell = words.at(args_end);
                 std::string pin = words.at(args_end + 1);
-                auto fnd_cell = ctx->cells.find(cell);
+                auto fnd_cell = ctx->cells.find(ctx->id(cell));
                 if (fnd_cell == ctx->cells.end()) {
                     log_warning("unmatched pcf constraint %s\n", cell.c_str());
                 } else {
@@ -60,10 +60,10 @@ bool apply_pcf(Context *ctx, std::istream &in)
                     if (pin_bel == BelId())
                         log_error("package does not have a pin named %s\n",
                                   pin.c_str());
-                    fnd_cell->second->attrs["BEL"] =
-                            ctx->getBelName(pin_bel).str();
+                    fnd_cell->second->attrs[ctx->id("BEL")] =
+                            ctx->getBelName(pin_bel).str(ctx);
                     log_info("constrained '%s' to bel '%s'\n", cell.c_str(),
-                             fnd_cell->second->attrs["BEL"].c_str());
+                             fnd_cell->second->attrs[ctx->id("BEL")].c_str());
                 }
             } else {
                 log_error("unsupported pcf command '%s'\n", cmd.c_str());