diff --git a/himbaechel/uarch/xilinx/xdc.cc b/himbaechel/uarch/xilinx/xdc.cc
index e6d76b59..1a16b9bd 100644
--- a/himbaechel/uarch/xilinx/xdc.cc
+++ b/himbaechel/uarch/xilinx/xdc.cc
@@ -39,9 +39,11 @@ void XilinxImpl::parse_xdc(const std::string &filename)
     std::ifstream in(filename);
     if (!in)
         log_error("failed to open XDC file '%s'\n", filename.c_str());
+    log_info("Parsing XDC file...\n");
     std::string line;
     std::string linebuf;
     int lineno = 0;
+    unsigned num_errors = 0;
 
     auto isempty = [](const std::string &str) {
         return std::all_of(str.begin(), str.end(), [](char c) { return std::isspace(c); });
@@ -109,8 +111,10 @@ void XilinxImpl::parse_xdc(const std::string &filename)
 
     auto get_nets = [&](std::string str) {
         std::vector<NetInfo *> tgt_nets;
-        if (str.empty() || str.front() != '[')
-            log_error("failed to parse target (on line %d)\n", lineno);
+        if (str.empty())
+            return tgt_nets;
+        if (str.front() != '[' || str.back() != ']')
+            log_error("failed to parse target '%s' (on line %d)\n", str.c_str(), lineno);
         str = str.substr(1, str.size() - 2);
         auto split = split_to_args(str, false);
         if (split.size() < 1)
@@ -141,12 +145,18 @@ void XilinxImpl::parse_xdc(const std::string &filename)
         std::string &cmd = arguments.front();
         if (cmd == "set_property") {
             std::vector<std::pair<std::string, std::string>> arg_pairs;
-            if (arguments.size() != 4)
-                log_error("expected four arguments to 'set_property' (on line %d)\n", lineno);
+            if (arguments.size() != 4) {
+                log_nonfatal_error("expected at four arguments to 'set_property' (on line %d)\n", lineno);
+                num_errors++;
+                goto nextline;
+            }
             else if (arguments.at(1) == "-dict") {
                 std::vector<std::string> dict_args = split_to_args(strip_quotes(arguments.at(2)), false);
-                if ((dict_args.size() % 2) != 0)
-                    log_error("expected an even number of argument for dictionary (on line %d)\n", lineno);
+                if ((dict_args.size() % 2) != 0) {
+                    log_nonfatal_error("expected an even number of argument for dictionary (on line %d)\n", lineno);
+                    num_errors++;
+                    goto nextline;
+                }
                 arg_pairs.reserve(dict_args.size() / 2);
                 for (int cursor = 0; cursor + 1 < int(dict_args.size()); cursor += 2) {
                     arg_pairs.emplace_back(std::move(dict_args.at(cursor)), std::move(dict_args.at(cursor + 1)));
@@ -154,8 +164,11 @@ void XilinxImpl::parse_xdc(const std::string &filename)
             } else {
                 arg_pairs.emplace_back(std::move(arguments.at(1)), std::move(arguments.at(2)));
             }
-            if (arg_pairs.size() == 1 && arg_pairs.front().first == "INTERNAL_VREF") // get_iobanks not supported
+            // Warning : ug835 has lowercase example, so probably supporting lowercase too is needed
+            if (arg_pairs.size() == 1 && arg_pairs.front().first == "INTERNAL_VREF") { // get_iobanks not supported
+                log_warning("INTERNAL_VREF isn't supported, ignoring (on line %d)\n", lineno);
                 continue;
+            }
             if (arguments.at(3).size() > 2 && arguments.at(3) == "[current_design]") {
                 log_warning("[current_design] isn't supported, ignoring (on line %d)\n", lineno);
                 continue;
@@ -170,32 +183,57 @@ void XilinxImpl::parse_xdc(const std::string &filename)
             int cursor = 1;
             for (cursor = 1; cursor < int(arguments.size()); cursor++) {
                 std::string opt = arguments.at(cursor);
-                if (opt == "-add")
-                    ;
-                else if (opt == "-name" || opt == "-waveform")
+                if (opt == "-add") {
+                    log_warning("ignoring unsupported XDC option '%s' (on line %d)\n", opt.c_str(), lineno);
+                }
+                else if (opt == "-name" || opt == "-waveform") {
+                    log_warning("ignoring unsupported XDC option '%s' (on line %d)\n", opt.c_str(), lineno);
                     cursor++;
+                }
                 else if (opt == "-period") {
                     cursor++;
                     period = std::stod(arguments.at(cursor));
                     got_period = true;
-                } else
+                }
+                else
                     break;
             }
-            if (!got_period)
-                log_error("found create_clock without period (on line %d)", lineno);
+            if (!got_period) {
+                log_nonfatal_error("found create_clock without period (on line %d)\n", lineno);
+                num_errors++;
+                goto nextline;
+            }
+            if (cursor >= int(arguments.size())) {
+                log_warning("found create_clock without designated nets (on line %d)\n", lineno);
+                goto nextline;
+            }
             std::vector<NetInfo *> dest = get_nets(arguments.at(cursor));
             for (auto n : dest) {
+                if (ctx->debug)
+                    log_info("applying clock period constraint on net '%s' (on line %d)\n", n->name.c_str(ctx), lineno);
+                if (n->clkconstr.get() != nullptr) {
+                    log_nonfatal_error("found multiple clock constraints on net '%s' (on line %d)\n", n->name.c_str(ctx), lineno);
+                    num_errors++;
+                }
                 n->clkconstr = std::unique_ptr<ClockConstraint>(new ClockConstraint);
                 n->clkconstr->period = DelayPair(ctx->getDelayFromNS(period));
                 n->clkconstr->high = DelayPair(ctx->getDelayFromNS(period / 2));
                 n->clkconstr->low = DelayPair(ctx->getDelayFromNS(period / 2));
             }
         } else {
-            log_info("ignoring unsupported XDC command '%s' (on line %d)\n", cmd.c_str(), lineno);
+            log_warning("ignoring unsupported XDC command '%s' (on line %d)\n", cmd.c_str(), lineno);
         }
+
+        nextline:
+        ;  // Phony statement to have something legal after the label
+    }
+    if (!isempty(linebuf)) {
+        log_nonfatal_error("unexpected end of XDC file\n");
+        num_errors++;
+    }
+    if (num_errors > 0) {
+        log_error("Stopping the program after %u errors found in XDC file\n", num_errors);
     }
-    if (!isempty(linebuf))
-        log_error("unexpected end of XDC file\n");
 }
 
 NEXTPNR_NAMESPACE_END