Support assignments of packed values to stream expressions on queues (v…

…erilator#4401)

include/verilated_funcs.h

@@ -1526,6 +1526,14 @@ static inline WDataOutP VL_STREAML_WWI(int lbits, WDataOutP owp, WDataInP const
     return owp;
 }
 
+template <typename T>
+static inline void VL_ASSIGN_DYN_Q(VlQueue<T>& q, int elem_size, int lbits, QData from) {
+    const int size = (lbits + elem_size - 1) / elem_size;
+    q.renew(size);
+    const QData mask = VL_MASK_Q(elem_size);
+    for (int i = 0; i < size; ++i) q.at(i) = (T)((from >> (i * elem_size)) & mask);
+}
+
 // Because concats are common and wide, it's valuable to always have a clean output.
 // Thus we specify inputs must be clean, so we don't need to clean the output.
 // Note the bit shifts are always constants, so the adds in these constify out.

src/V3AstNodeExpr.h

@@ -1013,6 +1013,20 @@ class AstConst final : public AstNodeExpr {
     // May return nullptr on parse failure.
     static AstConst* parseParamLiteral(FileLine* fl, const string& literal);
 };
+class AstCvtPackedToDynArray final : public AstNodeExpr {
+    // Cast from packed array to dynamic queue data type
+    // @astgen op1 := fromp : AstNodeExpr
+public:
+    AstCvtPackedToDynArray(FileLine* fl, AstNodeExpr* fromp, AstNodeDType* dtp)
+        : ASTGEN_SUPER_CvtPackedToDynArray(fl) {
+        this->fromp(fromp);
+        dtypeFrom(dtp);
+    }
+    ASTGEN_MEMBERS_AstCvtPackedToDynArray;
+    string emitVerilog() override { V3ERROR_NA_RETURN(""); }
+    string emitC() override { V3ERROR_NA_RETURN(""); }
+    bool cleanOut() const override { return true; }
+};
 class AstDot final : public AstNodeExpr {
     // A dot separating paths in an AstVarXRef, AstFuncRef or AstTaskRef
     // These are eliminated in the link stage

src/V3Const.cpp

@@ -2158,12 +2158,11 @@ class ConstVisitor final : public VNVisitor {
             return true;
         } else if (m_doV && VN_IS(nodep->lhsp(), StreamL)) {
             // Push the stream operator to the rhs of the assignment statement
-            const int dWidth = VN_AS(nodep->lhsp(), StreamL)->lhsp()->width();
-            const int sWidth = nodep->rhsp()->width();
-            // Unlink the stuff
-            AstNodeExpr* const dstp = VN_AS(nodep->lhsp(), StreamL)->lhsp()->unlinkFrBack();
-            AstNodeExpr* streamp = VN_AS(nodep->lhsp(), StreamL)->unlinkFrBack();
+            AstNodeExpr* streamp = nodep->lhsp()->unlinkFrBack();
+            AstNodeExpr* const dstp = VN_AS(streamp, StreamL)->lhsp()->unlinkFrBack();
             AstNodeExpr* const srcp = nodep->rhsp()->unlinkFrBack();
+            const int sWidth = srcp->width();
+            const int dWidth = dstp->width();
             // Connect the rhs to the stream operator and update its width
             VN_AS(streamp, StreamL)->lhsp(srcp);
             if (VN_IS(srcp->dtypep(), DynArrayDType) || VN_IS(srcp->dtypep(), QueueDType)
@@ -2172,26 +2171,27 @@ class ConstVisitor final : public VNVisitor {
             } else {
                 streamp->dtypeSetLogicUnsized(srcp->width(), srcp->widthMin(), VSigning::UNSIGNED);
             }
-            // Shrink the RHS if necessary
-            if (sWidth > dWidth) {
+            if (dWidth == 0) {
+                streamp = new AstCvtPackedToDynArray{nodep->fileline(), streamp, dstp->dtypep()};
+            } else if (sWidth > dWidth) {
                 streamp = new AstSel{streamp->fileline(), streamp, sWidth - dWidth, dWidth};
             }
-            // Link the nodes back in
             nodep->lhsp(dstp);
             nodep->rhsp(streamp);
             return true;
         } else if (m_doV && VN_IS(nodep->lhsp(), StreamR)) {
             // The right stream operator on lhs of assignment statement does
             // not reorder bits. However, if the rhs is wider than the lhs,
             // then we select bits from the left-most, not the right-most.
-            const int dWidth = VN_AS(nodep->lhsp(), StreamR)->lhsp()->width();
-            const int sWidth = nodep->rhsp()->width();
-            // Unlink the stuff
-            AstNodeExpr* const dstp = VN_AS(nodep->lhsp(), StreamR)->lhsp()->unlinkFrBack();
-            AstNode* const sizep = VN_AS(nodep->lhsp(), StreamR)->rhsp()->unlinkFrBack();
-            AstNodeExpr* const streamp = VN_AS(nodep->lhsp(), StreamR)->unlinkFrBack();
+            AstNodeExpr* const streamp = nodep->lhsp()->unlinkFrBack();
+            AstNodeExpr* const dstp = VN_AS(streamp, StreamR)->lhsp()->unlinkFrBack();
+            AstNode* const sizep = VN_AS(streamp, StreamR)->rhsp()->unlinkFrBack();
             AstNodeExpr* srcp = nodep->rhsp()->unlinkFrBack();
-            if (sWidth > dWidth) {
+            const int sWidth = srcp->width();
+            const int dWidth = dstp->width();
+            if (dWidth == 0) {
+                srcp = new AstCvtPackedToDynArray{nodep->fileline(), srcp, dstp->dtypep()};
+            } else if (sWidth > dWidth) {
                 srcp = new AstSel{streamp->fileline(), srcp, sWidth - dWidth, dWidth};
             }
             nodep->lhsp(dstp);

src/V3EmitCFunc.h

@@ -401,6 +401,19 @@ class EmitCFunc VL_NOT_FINAL : public EmitCConstInit {
             puts(cvtToStr(nodep->widthMin()) + ",");
             iterateAndNextConstNull(nodep->lhsp());
             puts(", ");
+        } else if (const AstCvtPackedToDynArray* const castp
+                   = VN_CAST(nodep->rhsp(), CvtPackedToDynArray)) {
+            puts("VL_ASSIGN_DYN_Q<");
+            putbs(castp->dtypep()->subDTypep()->cType("", false, false));
+            puts(">(");
+            iterateAndNextConstNull(nodep->lhsp());
+            puts(", ");
+            puts(cvtToStr(castp->dtypep()->subDTypep()->widthMin()));
+            puts(", ");
+            puts(cvtToStr(castp->fromp()->widthMin()));
+            puts(", ");
+            rhs = false;
+            iterateAndNextConstNull(castp->fromp());
         } else if (nodep->isWide() && VN_IS(nodep->lhsp(), VarRef)  //
                    && !VN_IS(nodep->rhsp(), CExpr)  //
                    && !VN_IS(nodep->rhsp(), CMethodHard)  //

src/V3Width.cpp

@@ -840,9 +840,13 @@ class WidthVisitor final : public VNVisitor {
             } else {
                 nodep->v3error("Slice size isn't a constant or basic data type.");
             }
-            if (VN_IS(nodep->lhsp()->dtypep(), DynArrayDType)
-                || VN_IS(nodep->lhsp()->dtypep(), QueueDType)
-                || VN_IS(nodep->lhsp()->dtypep(), UnpackArrayDType)) {
+            const AstNodeDType* const lhsDtypep = nodep->lhsp()->dtypep();
+            if (VN_IS(lhsDtypep, DynArrayDType) || VN_IS(lhsDtypep, QueueDType)) {
+                nodep->dtypeSetStream();
+            } else if (VN_IS(lhsDtypep, UnpackArrayDType) || lhsDtypep->isCompound()) {
+                nodep->v3warn(E_UNSUPPORTED,
+                              "Unsupported: Stream operation on a variable of a type "
+                                  << lhsDtypep->prettyDTypeNameQ());
                 nodep->dtypeSetStream();
             } else {
                 nodep->dtypeSetLogicUnsized(nodep->lhsp()->width(), nodep->lhsp()->widthMin(),

test_regress/t/t_stream_bad.out

@@ -6,4 +6,9 @@
                               : ... In instance t
    12 |    initial packed_data_32 = {<<$random{byte_in}};
       |                              ^~
+%Error-UNSUPPORTED: t/t_stream_bad.v:12:30: Unsupported: Stream operation on a variable of a type 'byte$[0:3]'
+                                          : ... In instance t
+   12 |    initial packed_data_32 = {<<$random{byte_in}};
+      |                              ^~
+                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
 %Error: Exiting due to

test_regress/t/t_stream_dynamic.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2020 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;

test_regress/t/t_stream_dynamic.v

@@ -0,0 +1,40 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2023 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+`define stop $stop
+`define checks(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got='%s' exp='%s'\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
+
+module t (/*AUTOARG*/);
+   initial begin
+      bit arr[];
+      bit [1:0] arr2[$];
+      bit [4:0] arr5[];
+      bit [5:0] arr6[$];
+      string v;
+      bit [5:0] bit6 = 6'b111000;
+
+      { >> bit {arr}} = bit6;
+      v = $sformatf("%p", arr); `checks(v, "'{'h0, 'h0, 'h0, 'h1, 'h1, 'h1} ");
+
+      { << bit {arr}} = bit6;
+      v = $sformatf("%p", arr); `checks(v, "'{'h1, 'h1, 'h1, 'h0, 'h0, 'h0} ");
+
+      { >> bit[1:0] {arr2}} = bit6;
+      v = $sformatf("%p", arr2); `checks(v, "'{'h0, 'h2, 'h3} ");
+
+      { << bit[1:0] {arr2}} = bit6;
+      v = $sformatf("%p", arr2); `checks(v, "'{'h3, 'h2, 'h0} ");
+
+      { >> bit [5:0] {arr6} } = bit6;
+      v = $sformatf("%p", arr6); `checks(v, "'{'h38} ");
+
+      { << bit [5:0] {arr6} } = bit6;
+      v = $sformatf("%p", arr6); `checks(v, "'{'h38} ");
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule