sdc: error on unknown getters

passes/cmds/sdc/graph-stubs.sdc

@@ -1,4 +1,21 @@
 proc unknown {args} {
+    # Check if it's a getter
+    if {[llength $args] > 0} {
+        set first_arg [lindex $args 0]
+        if {[string match "get_*" $first_arg]} {
+            # It's a getter, has it been redirected from specialized C++ code?
+            if {[llength $args] > 1} {
+                set second_arg [lindex $args 1]
+                if {$second_arg ne "-getter-validated"} {
+                    error "Unknown getter: $first_arg"
+                }
+            } else {
+                error "Unknown getter: $first_arg"
+            }
+        }
+    }
+    # TODO this safety feature could be optional via a global
+
     global sdc_call_index
     global sdc_calls
     if {![info exists sdc_call_index]} {
@@ -15,4 +32,11 @@ proc unknown {args} {
 }
 proc list {args} {
     return [unknown "list" {*}$args]
-}
+}
+proc get_clocks {args} {
+    # get_clocks isn't a design object getter
+    # because clocks aren't design objects, just aliases
+    # so the referred to clock pin already are being tracked
+    # as arguments of uninterpreted create_clock command or similar
+    return [unknown "get_clocks" "-getter-validated" {*}$args]
+}

passes/cmds/sdc/sdc.cc

@@ -344,9 +344,32 @@ static std::pair<bool, BitSelection> matches(std::string name, const std::string
 	}
 }
 
-static int graph_node(TclCall call) {
-	// TODO is that it?
-	return redirect_unknown(call);
+static int getter_graph_node(TclCall call) {
+	// Insert -getter-validated as first argument for passing to unknown
+	// to distinguish resolved and unknown getters.
+	// For example, if call is ["get_foo", "-bar"]
+	// then newCall is ["get_foo", "-getter-validated", "-bar"]
+    Tcl_Obj* validity_tag = Tcl_NewStringObj("-getter-validated", -1);
+    Tcl_IncrRefCount(validity_tag);
+	std::vector<Tcl_Obj*> newObjv(call.objc + 1);
+    log_assert(call.objc > 0);
+	newObjv[0] = call.objv[0];
+    newObjv[1] = validity_tag;
+    for (int i = 1; i < call.objc; ++i) {
+        newObjv[i + 1] = call.objv[i];
+    }
+	// Send the vector to the Tcl land
+    Tcl_Obj** allocatedObjv = new Tcl_Obj*[call.objc + 1];
+    for (int i = 0; i < call.objc + 1; ++i) {
+        allocatedObjv[i] = newObjv[i];
+    }
+	TclCall newCall {
+		.interp = call.interp,
+		.objc = call.objc + 1,
+		.objv = allocatedObjv
+	};
+	// Finally, redirect to unknown handler
+	return redirect_unknown(newCall);
 }
 
 static int redirect_unknown(TclCall call) {
@@ -610,7 +633,7 @@ static int sdc_get_pins_cmd(ClientData data, Tcl_Interp *interp, int objc, Tcl_O
 	const auto& pins = objects->design_pins;
 	resolved = find_matching<SdcObjects::CellPin, decltype(pins)>(pins, config, opts.patterns, "pin");
 
-	return graph_node(TclCall{interp, objc, objv});
+	return getter_graph_node(TclCall{interp, objc, objv});
 }
 
 static int sdc_get_ports_cmd(ClientData data, Tcl_Interp *interp, int objc, Tcl_Obj* const objv[])
@@ -631,7 +654,7 @@ static int sdc_get_ports_cmd(ClientData data, Tcl_Interp *interp, int objc, Tcl_
 			merge_or_init(std::make_pair(name, wire), objects->constrained_ports, matching_bits);
 	}
 
-	return graph_node(TclCall{interp, objc, objv});
+	return getter_graph_node(TclCall{interp, objc, objv});
 }
 
 static int sdc_get_nets_cmd(ClientData data, Tcl_Interp *interp, int objc, Tcl_Obj* const objv[])
@@ -652,7 +675,7 @@ static int sdc_get_nets_cmd(ClientData data, Tcl_Interp *interp, int objc, Tcl_O
 			merge_or_init(std::make_pair(name, wire), objects->constrained_nets, matching_bits);
 	}
 
-	return graph_node(TclCall{interp, objc, objv});
+	return getter_graph_node(TclCall{interp, objc, objv});
 }
 
 class SDCInterpreter

tests/sdc/get_foo.sdc

@@ -0,0 +1 @@
+get_foo -bar 1

tests/sdc/unknown-getter.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+! ../../yosys -p 'read_verilog alu_sub.v; proc; hierarchy -auto-top; sdc get_foo.sdc' 2>&1 | grep 'Unknown getter'