Support NBAs in non-inlined functions/tasks

Signed-off-by: Krzysztof Bieganski <[email protected]>
antmicro · Oct 15, 2023 · d708b5b · d708b5b
1 parent d9564d3
commit d708b5b
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Showing 6 changed files with 142 additions and 32 deletions.
diff --git a/src/V3AstNodeOther.h b/src/V3AstNodeOther.h
@@ -1191,6 +1191,7 @@ class AstNetlist final : public AstNode {
     AstCFunc* m_evalNbap = nullptr;  // The '_eval__nba' function
     AstVarScope* m_dpiExportTriggerp = nullptr;  // The DPI export trigger variable
     AstVar* m_delaySchedulerp = nullptr;  // The delay scheduler variable
+    AstVarScope* m_nbaEventp = nullptr;  // The NBA event variable
     AstTopScope* m_topScopep = nullptr;  // The singleton AstTopScope under the top module
     VTimescale m_timeunit;  // Global time unit
     VTimescale m_timeprecision;  // Global time precision
@@ -1220,6 +1221,8 @@ class AstNetlist final : public AstNode {
     void dpiExportTriggerp(AstVarScope* varScopep) { m_dpiExportTriggerp = varScopep; }
     AstVar* delaySchedulerp() const { return m_delaySchedulerp; }
     void delaySchedulerp(AstVar* const varScopep) { m_delaySchedulerp = varScopep; }
+    AstVarScope* nbaEventp() const { return m_nbaEventp; }
+    void nbaEventp(AstVarScope* const varScopep) { m_nbaEventp = varScopep; }
     void stdPackagep(AstPackage* const packagep) { m_stdPackagep = packagep; }
     AstPackage* stdPackagep() const { return m_stdPackagep; }
     AstTopScope* topScopep() const { return m_topScopep; }

diff --git a/src/V3Delayed.cpp b/src/V3Delayed.cpp
@@ -527,8 +527,10 @@ class DelayedVisitor final : public VNVisitor {
         m_nextDlyp
             = VN_CAST(nodep->nextp(), AssignDly);  // Next assignment in same block, maybe nullptr.
         if (m_cfuncp) {
-            nodep->v3warn(E_UNSUPPORTED,
-                          "Unsupported: Delayed assignment inside public function/task");
+            if (v3Global.rootp()->nbaEventp()) return;
+            nodep->v3warn(
+                E_UNSUPPORTED,
+                "Unsupported: Delayed assignment in a non-inlined function/task without --timing");
         }
         UASSERT_OBJ(m_procp, nodep, "Delayed assignment not under process");
         const bool isArray = VN_IS(nodep->lhsp(), ArraySel)

diff --git a/src/V3Sched.cpp b/src/V3Sched.cpp
@@ -591,18 +591,27 @@ const TriggerKit createTriggers(AstNetlist* netlistp, AstCFunc* const initFuncp,
     return {vscp, funcp, dumpp, map};
 }
 
+//============================================================================
+// EvalLoop contains elements of an evaluation loop created by makeEvalLoop()
+
+struct EvalLoop {
+    // Loop iteration counter for enforcing the converge limit
+    AstVarScope* counterp = nullptr;
+    // The loop condition
+    AstVarScope* continuep = nullptr;
+    // The loop itself and statements around it
+    AstNodeStmt* stmtsp = nullptr;
+};
+
 //============================================================================
 // Helpers to construct an evaluation loop.
 
-AstNodeStmt* buildLoop(AstNetlist* netlistp, const string& name,
-                       const std::function<void(AstVarScope*, AstWhile*)>& build)  //
+AstNodeStmt* buildLoop(AstNetlist* netlistp, AstVarScope* const condp,
+                       const std::function<void(AstWhile*)>& build)  //
 {
     AstTopScope* const topScopep = netlistp->topScopep();
     AstScope* const scopeTopp = topScopep->scopep();
     FileLine* const flp = scopeTopp->fileline();
-    // Create the loop condition variable
-    AstVarScope* const condp = scopeTopp->createTemp("__V" + name + "Continue", 1);
-    condp->varp()->noReset(true);
     // Initialize the loop condition variable to true
     AstNodeStmt* const resp = setVar(condp, 1);
     // Add the loop
@@ -611,16 +620,15 @@ AstNodeStmt* buildLoop(AstNetlist* netlistp, const string& name,
     // Clear the loop condition variable in the loop
     loopp->addStmtsp(setVar(condp, 0));
     // Build the body
-    build(condp, loopp);
+    build(loopp);
     // Done
     return resp;
 };
 
-std::pair<AstVarScope*, AstNodeStmt*> makeEvalLoop(AstNetlist* netlistp, const string& tag,
-                                                   const string& name, AstVarScope* trigVscp,
-                                                   AstCFunc* trigDumpp,
-                                                   std::function<AstNodeStmt*()> computeTriggers,
-                                                   std::function<AstNodeStmt*()> makeBody) {
+EvalLoop makeEvalLoop(AstNetlist* netlistp, const string& tag, const string& name,
+                      AstVarScope* trigVscp, AstCFunc* trigDumpp,
+                      std::function<AstNodeStmt*()> computeTriggers,
+                      std::function<AstNodeStmt*()> makeBody) {
     UASSERT_OBJ(trigVscp->dtypep()->basicp()->isTriggerVec(), trigVscp, "Not TRIGGERVEC");
     AstTopScope* const topScopep = netlistp->topScopep();
     AstScope* const scopeTopp = topScopep->scopep();
@@ -629,8 +637,11 @@ std::pair<AstVarScope*, AstNodeStmt*> makeEvalLoop(AstNetlist* netlistp, const s
     AstVarScope* const counterp = scopeTopp->createTemp("__V" + tag + "IterCount", 32);
     counterp->varp()->noReset(true);
 
+    AstVarScope* const continuep = scopeTopp->createTemp("__V" + tag + "Continue", 1);
+    continuep->varp()->noReset(true);
+
     AstNodeStmt* nodep = setVar(counterp, 0);
-    nodep->addNext(buildLoop(netlistp, tag, [&](AstVarScope* continuep, AstWhile* loopp) {
+    nodep->addNext(buildLoop(netlistp, continuep, [&](AstWhile* loopp) {
         // Compute triggers
         loopp->addStmtsp(computeTriggers());
         // Invoke body if triggered
@@ -682,7 +693,7 @@ std::pair<AstVarScope*, AstNodeStmt*> makeEvalLoop(AstNetlist* netlistp, const s
         }
     }));
 
-    return {counterp, nodep};
+    return {counterp, continuep, nodep};
 }
 
 //============================================================================
@@ -727,7 +738,7 @@ void createSettle(AstNetlist* netlistp, AstCFunc* const initFuncp, SenExprBuilde
     splitCheck(stlFuncp);
 
     // Create the eval loop
-    const auto& pair = makeEvalLoop(
+    const auto& loop = makeEvalLoop(
         netlistp, "stl", "Settle", trig.m_vscp, trig.m_dumpp,
         [&]() {  // Trigger
             AstCCall* const callp = new AstCCall{stlFuncp->fileline(), trig.m_funcp};
@@ -741,10 +752,10 @@ void createSettle(AstNetlist* netlistp, AstCFunc* const initFuncp, SenExprBuilde
         });
 
     // Add the first iteration trigger to the trigger computation function
-    trig.addFirstIterationTriggerAssignment(pair.first, firstIterationTrigger);
+    trig.addFirstIterationTriggerAssignment(loop.counterp, firstIterationTrigger);
 
     // Add the eval loop to the top function
-    funcp->addStmtsp(pair.second);
+    funcp->addStmtsp(loop.stmtsp);
 }
 
 //============================================================================
@@ -816,7 +827,7 @@ AstNode* createInputCombLoop(AstNetlist* netlistp, AstCFunc* const initFuncp,
     splitCheck(icoFuncp);
 
     // Create the eval loop
-    const auto& pair = makeEvalLoop(
+    const auto& loop = makeEvalLoop(
         netlistp, "ico", "Input combinational", trig.m_vscp, trig.m_dumpp,
         [&]() {  // Trigger
             AstCCall* const callp = new AstCCall{icoFuncp->fileline(), trig.m_funcp};
@@ -830,10 +841,10 @@ AstNode* createInputCombLoop(AstNetlist* netlistp, AstCFunc* const initFuncp,
         });
 
     // Add the first iteration trigger to the trigger computation function
-    trig.addFirstIterationTriggerAssignment(pair.first, firstIterationTrigger);
+    trig.addFirstIterationTriggerAssignment(loop.counterp, firstIterationTrigger);
 
     // Return the eval loop itself
-    return pair.second;
+    return loop.stmtsp;
 }
 
 //============================================================================
@@ -927,11 +938,10 @@ void createEval(AstNetlist* netlistp,  //
                   }
 
                   return resultp;
-              })
-              .second;
+              }).stmtsp;
 
     // Create the NBA eval loop. This uses the Active eval loop in the trigger section.
-    AstNodeStmt* topEvalLoopp
+    const auto& nbaEvalLoop
         = makeEvalLoop(
               netlistp, "nba", "NBA", nbaKit.m_vscp, nbaKit.m_dumpp,
               [&]() {  // Trigger
@@ -952,8 +962,23 @@ void createEval(AstNetlist* netlistp,  //
                           resultp, createTriggerSetCall(flp, nextVscp, nbaKit.m_vscp));
                   }
                   return resultp;
-              })
-              .second;
+              });
+
+    // If the NBA event exists, trigger it in 'nba'
+    if (netlistp->nbaEventp()) {
+        AstCMethodHard* const triggeredp = new AstCMethodHard{
+            flp, new AstVarRef{flp, netlistp->nbaEventp(), VAccess::READ}, "isTriggered"};
+        triggeredp->dtypeSetBit();
+        AstIf* const ifp = new AstIf{flp, new AstLogNot{flp, triggeredp}};
+        ifp->addThensp(setVar(nbaEvalLoop.continuep, 1));
+        AstCMethodHard* const firep = new AstCMethodHard{
+            flp, new AstVarRef{flp, netlistp->nbaEventp(), VAccess::WRITE}, "fire"};
+        firep->dtypeSetVoid();
+        ifp->addThensp(firep->makeStmt());
+        nbaEvalLoop.stmtsp->addNext(ifp);
+    }
+
+    AstNodeStmt* topEvalLoopp = nbaEvalLoop.stmtsp;
 
     if (obsKit.m_funcp) {
         // Create the Observed eval loop. This uses the NBA eval loop in the trigger section.
@@ -978,7 +1003,7 @@ void createEval(AstNetlist* netlistp,  //
                       }
                       return resultp;
                   })
-                  .second;
+                  .stmtsp;
     }
 
     if (reactKit.m_funcp) {
@@ -997,7 +1022,7 @@ void createEval(AstNetlist* netlistp,  //
                                callp->dtypeSetVoid();
                                return callp->makeStmt();
                            })
-                           .second;
+                           .stmtsp;
     }
     funcp->addStmtsp(topEvalLoopp);
 

diff --git a/src/V3Timing.cpp b/src/V3Timing.cpp
@@ -409,6 +409,7 @@ class TimingControlVisitor final : public VNVisitor {
     AstBasicDType* m_trigSchedDtp = nullptr;  // Trigger scheduler type
 
     // Timing-related globals
+    AstVarScope* m_nbaEventp = nullptr;  // Event triggered in NBA region
     AstVarScope* m_delaySchedp = nullptr;  // Global delay scheduler
     AstVarScope* m_dynamicSchedp = nullptr;  // Global dynamic trigger scheduler
     AstSenTree* m_delaySensesp = nullptr;  // Domain to trigger if a delayed coroutine is resumed
@@ -518,6 +519,22 @@ class TimingControlVisitor final : public VNVisitor {
         m_netlistp->topScopep()->addSenTreesp(m_dynamicSensesp);
         return m_dynamicSensesp;
     }
+    // Creates the event variable to trigger in NBA region
+    AstEventControl* createNbaEventControl(FileLine* flp) {
+        if (!m_nbaEventp) {
+            auto* const nbaEventDtp = new AstBasicDType{m_scopeTopp->fileline(),
+                                                        VBasicDTypeKwd::EVENT, VSigning::UNSIGNED};
+            m_netlistp->typeTablep()->addTypesp(nbaEventDtp);
+            m_nbaEventp = m_scopeTopp->createTemp("__VnbaEvent", nbaEventDtp);
+            m_netlistp->nbaEventp(m_nbaEventp);
+            v3Global.setHasEvents();
+        }
+        return new AstEventControl{
+            flp,
+            new AstSenTree{flp, new AstSenItem{flp, VEdgeType::ET_EVENT,
+                                               new AstVarRef{flp, m_nbaEventp, VAccess::READ}}},
+            nullptr};
+    }
     // Returns true if we are under a class or the given tree has any references to locals. These
     // are cases where static, globally-evaluated triggers are not suitable.
     bool needDynamicTrigger(AstNode* const nodep) const {
@@ -922,17 +939,31 @@ class TimingControlVisitor final : public VNVisitor {
     void visit(AstNodeAssign* nodep) override {
         // Only process once to avoid infinite loops (due to the net delay)
         if (nodep->user1SetOnce()) return;
-        AstNode* const controlp = factorOutTimingControl(nodep);
-        if (!controlp) return;
-        // Handle the intra assignment timing control
         FileLine* const flp = nodep->fileline();
-        if (VN_IS(nodep, AssignDly)) {
+        AstNode* controlp = factorOutTimingControl(nodep);
+        const bool inAssignDly = VN_IS(nodep, AssignDly);
+        const bool nonInlined = !VN_IS(m_procp, NodeProcedure);
+        // Transform if:
+        // * there's a timing control in the assignment
+        // * the assignment is an AssignDly and it's in a non-inlined function
+        if (!controlp && !(inAssignDly && nonInlined)) return;
+        // Handle the intra assignment timing control
+        if (inAssignDly) {
             // If it's an NBA with an intra assignment delay, put it in a fork
             auto* const forkp = new AstFork{flp, "", nullptr};
             forkp->joinType(VJoinType::JOIN_NONE);
+            if (nonInlined) {
+                auto nbaEventControlp = createNbaEventControl(flp);
+                nodep->replaceWith(nbaEventControlp);
+                nbaEventControlp->addStmtsp(nodep);
+                if (!controlp) {
+                    controlp = nbaEventControlp;
+                }
+            }
             controlp->replaceWith(forkp);
             forkp->addStmtsp(controlp);
         }
+        UASSERT_OBJ(nodep, controlp, "Assignment should have timing control");
         // Insert new vars before the timing control if we're in a function; in a process we can't
         // do that. These intra-assignment vars will later be passed to forked processes by value.
         AstNode* const insertBeforep = m_classp ? controlp : nullptr;

diff --git a/test_regress/t/t_dynamic_nba.pl b/test_regress/t/t_dynamic_nba.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2019 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(
+    verilator_flags2 => ["--exe --main --timing"],
+    make_main => 0,
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_dynamic_nba.v b/test_regress/t/t_dynamic_nba.v
@@ -0,0 +1,26 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2023 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+class nba_waiter;
+    task wait_for_nba_region;
+      int nba;
+      int next_nba;
+      next_nba++;
+      nba <= next_nba;
+      @(nba);
+    endtask
+endclass
+
+module t;
+    nba_waiter waiter = new;
+    initial begin
+        waiter.wait_for_nba_region;
+        $write("*-* All Finished *-*\n");
+        $finish;
+    end
+endmodule
+
+