Support inside array constraints (#5448)

Signed-off-by: Arkadiusz Kozdra <akozdra@antmicro.com>

src/V3Randomize.cpp

@@ -557,6 +557,21 @@ class ConstraintExprVisitor final : public VNVisitor {
         return new AstSFormatF{fl, fmt.str(), false, exprsp};
     }
 
+    AstNodeExpr* newSel(FileLine* fl, AstNodeExpr* arrayp, AstNodeExpr* idxp) {
+        // similar to V3WidthSel.cpp
+        AstNodeDType* const arrDtp = arrayp->unlinkFrBack()->dtypep();
+        AstNodeExpr* selp = nullptr;
+        if (VN_IS(arrDtp, QueueDType) || VN_IS(arrDtp, DynArrayDType))
+            selp = new AstCMethodHard{fl, arrayp, "at", idxp};
+        else if (VN_IS(arrDtp, UnpackArrayDType))
+            selp = new AstArraySel{fl, arrayp, idxp};
+        else if (VN_IS(arrDtp, AssocArrayDType))
+            selp = new AstAssocSel{fl, arrayp, idxp};
+        UASSERT_OBJ(selp, arrayp, "Selecting from non-array?");
+        selp->dtypep(arrDtp->subDTypep());
+        return selp;
+    }
+
     // VISITORS
     void visit(AstNodeVarRef* nodep) override {
         AstVar* const varp = nodep->varp();
@@ -699,8 +714,7 @@ class ConstraintExprVisitor final : public VNVisitor {
                 new AstForeach{fl, nodep->arrayp()->unlinkFrBack(), new AstCStmt{fl, cstmtp}},
                 false, true});
             exprsp->addNext(
-                new AstText{fl, "return ret.empty() ? \"#b1\" : \"(bvand \" + ret + \")\";"});
+                new AstText{fl, "return ret.empty() ? \"#b1\" : \"(bvand\" + ret + \")\";})()"});
-            exprsp->addNext(new AstText{fl, "return ret + \")\"; })()"});
             AstNodeExpr* const newp = new AstCExpr{fl, exprsp};
             newp->dtypeSetString();
             nodep->replaceWith(new AstSFormatF{fl, "%@", false, newp});
@@ -741,18 +755,45 @@ class ConstraintExprVisitor final : public VNVisitor {
     }
     void visit(AstCMethodHard* nodep) override {
         if (editFormat(nodep)) return;
+        FileLine* const fl = nodep->fileline();
 
         if (nodep->name() == "at" && nodep->fromp()->user1()) {
             iterateChildren(nodep);
             AstNodeExpr* const argsp
                 = AstNode::addNext(nodep->fromp()->unlinkFrBack(), nodep->pinsp()->unlinkFrBack());
-            AstSFormatF* const newp
+            AstSFormatF* const newp = new AstSFormatF{fl, "(select %@ %@)", false, argsp};
-                = new AstSFormatF{nodep->fileline(), "(select %@ %@)", false, argsp};
             nodep->replaceWith(newp);
             VL_DO_DANGLING(nodep->deleteTree(), nodep);
             return;
         }
 
+        if (nodep->name() == "inside") {
+            bool randArr = nodep->fromp()->user1();
+
+            AstVar* const newVarp
+                = new AstVar{fl, VVarType::BLOCKTEMP, "__Vinside", nodep->findSigned32DType()};
+            AstNodeExpr* const idxRefp = new AstVarRef{nodep->fileline(), newVarp, VAccess::READ};
+            AstSelLoopVars* const arrayp
+                = new AstSelLoopVars{fl, nodep->fromp()->cloneTreePure(false), newVarp};
+            AstNodeExpr* const selp = newSel(nodep->fileline(), nodep->fromp(), idxRefp);
+            selp->user1(randArr);
+            AstNode* const itemp = new AstEq{fl, selp, nodep->pinsp()->unlinkFrBack()};
+            itemp->user1(true);
+            AstNode* const cstmtp = new AstText{fl, "ret += \" \" + "};
+            cstmtp->addNext(iterateSubtreeReturnEdits(itemp));
+            cstmtp->addNext(new AstText{fl, ";"});
+            AstNode* const exprsp = new AstText{fl, "([&]{ std::string ret;"};
+            exprsp->addNext(new AstBegin{
+                fl, "", new AstForeach{fl, arrayp, new AstCStmt{fl, cstmtp}}, false, true});
+            exprsp->addNext(
+                new AstText{fl, "return ret.empty() ? \"#b0\" : \"(bvor\" + ret + \")\";})()"});
+            AstNodeExpr* const newp = new AstCExpr{fl, exprsp};
+            newp->dtypeSetString();
+            nodep->replaceWith(new AstSFormatF{fl, "%@", false, newp});
+            VL_DO_DANGLING(nodep->deleteTree(), nodep);
+            return;
+        }
+
         nodep->v3warn(CONSTRAINTIGN,
                       "Unsupported: randomizing this expression, treating as state");
         nodep->user1(false);

test_regress/t/t_constraint_dist.v

@@ -20,12 +20,18 @@ begin \
 end
 
 class C;
-   rand int x, y;
+   rand int x, y, z, w;
+   int que[$] = '{3, 4, 5};
+   int arr[3] = '{5, 6, 7};
    constraint distrib {
       x dist { [1:3] := 0, [5:6], [9:15] :/ 0 };
       y dist { [1:3] := 0, 5, 6 := 8, [9:15] :/ 0 };
       x < 20;
    };
+   constraint distinside {
+       z dist {que};
+       w dist {arr};
+   };
 endclass
 
 module t;
@@ -33,6 +39,8 @@ module t;
       C c = new;
       `check_rand(c, c.x, 5 <= c.x && c.x <= 6);
       `check_rand(c, c.y, 5 <= c.y && c.y <= 6);
+      `check_rand(c, c.z, 3 <= c.z && c.z <= 5);
+      `check_rand(c, c.w, 5 <= c.w && c.w <= 7);
       $write("*-* All Finished *-*\n");
       $finish;
    end

test_regress/t/t_constraint_dist_unsup.out

@@ -1,17 +0,0 @@
-%Warning-CONSTRAINTIGN: t/t_constraint_dist_unsup.v:27:10: Constraint expression ignored (imperfect distribution)
-                                                         : ... note: In instance 't'
-   27 |        x dist {que};
-      |          ^~~~
-                        ... For warning description see https://verilator.org/warn/CONSTRAINTIGN?v=latest
-                        ... Use "/* verilator lint_off CONSTRAINTIGN */" and lint_on around source to disable this message.
-%Warning-CONSTRAINTIGN: t/t_constraint_dist_unsup.v:28:10: Constraint expression ignored (imperfect distribution)
-                                                         : ... note: In instance 't'
-   28 |        y dist {arr};
-      |          ^~~~
-%Warning-CONSTRAINTIGN: t/t_constraint_dist_unsup.v:27:10: Unsupported: randomizing this expression, treating as state
-   27 |        x dist {que};
-      |          ^~~~
-%Warning-CONSTRAINTIGN: t/t_constraint_dist_unsup.v:28:10: Unsupported: randomizing this expression, treating as state
-   28 |        y dist {arr};
-      |          ^~~~
-%Error: Exiting due to

test_regress/t/t_constraint_dist_unsup.py

@@ -1,16 +0,0 @@
-#!/usr/bin/env python3
-# DESCRIPTION: Verilator: Verilog Test driver/expect definition
-#
-# Copyright 2024 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
-
-import vltest_bootstrap
-
-test.scenarios('linter')
-
-test.lint(fails=test.vlt_all, expect_filename=test.golden_filename)
-
-test.passes()

test_regress/t/t_constraint_dist_unsup.v

@@ -1,40 +0,0 @@
-// DESCRIPTION: Verilator: Verilog Test module
-//
-// This file ONLY is placed under the Creative Commons Public Domain, for
-// any use, without warranty, 2024 by Antmicro Ltd.
-// SPDX-License-Identifier: CC0-1.0
-
-`define check_rand(cl, field, cond) \
-begin \
-   longint prev_result; \
-   int ok = 0; \
-   for (int i = 0; i < 10; i++) begin \
-      longint result; \
-      if (!bit'(cl.randomize())) $stop; \
-      result = longint'(field); \
-      if (!(cond)) $stop; \
-      if (i > 0 && result != prev_result) ok = 1; \
-      prev_result = result; \
-   end \
-   if (ok != 1) $stop; \
-end
-
-class C;
-   int que[$] = '{3, 4, 5};
-   int arr[3] = '{5, 6, 7};
-   rand int x, y;
-   constraint distrib {
-       x dist {que};
-       y dist {arr};
-   };
-endclass
-
-module t;
-   initial begin
-      C c = new;
-      `check_rand(c, c.x, 3 <= c.x && c.x <= 5);
-      `check_rand(c, c.y, 5 <= c.y && c.y <= 7);
-      $write("*-* All Finished *-*\n");
-      $finish;
-   end
-endmodule