Add extra triggers for virtual interfaces

Signed-off-by: Krzysztof Bieganski <kbieganski@antmicro.com>

src/CMakeLists.txt

@@ -282,6 +282,7 @@ set(COMMON_SOURCES
     V3SchedPartition.cpp
     V3SchedReplicate.cpp
     V3SchedTiming.cpp
+    V3SchedVirtIface.cpp
     V3Scope.cpp
     V3Scoreboard.cpp
     V3Slice.cpp

src/Makefile_obj.in

@@ -274,6 +274,7 @@ RAW_OBJS_PCH_ASTNOMT = \
 	V3SchedPartition.o \
 	V3SchedReplicate.o \
 	V3SchedTiming.o \
+	V3SchedVirtIface.o \
 	V3Scope.o \
 	V3Scoreboard.o \
 	V3Slice.o \

src/V3AstNodeDType.h

@@ -834,6 +834,7 @@ class AstEnumDType final : public AstNodeDType {
 class AstIfaceRefDType final : public AstNodeDType {
     // Reference to an interface, either for a port, or inside parent cell
     // @astgen op1 := paramsp : List[AstPin]
+    bool m_virtual = false;  // True if virtual interface
     FileLine* m_modportFileline;  // Where modport token was
     string m_cellName;  // "" = no cell, such as when connects to 'input' iface
     string m_ifaceName;  // Interface name
@@ -876,6 +877,11 @@ class AstIfaceRefDType final : public AstNodeDType {
     bool similarDType(const AstNodeDType* samep) const override { return this == samep; }
     int widthAlignBytes() const override { return 1; }
     int widthTotalBytes() const override { return 1; }
+    void isVirtual(bool flag) {
+        m_virtual = flag;
+        if (flag) v3Global.setHasVirtIfaces();
+    }
+    bool isVirtual() const { return m_virtual; }
     FileLine* modportFileline() const { return m_modportFileline; }
     string cellName() const { return m_cellName; }
     void cellName(const string& name) { m_cellName = name; }

src/V3AstNodeOther.h

@@ -1727,6 +1727,7 @@ class AstVar final : public AstNode {
     VLifetime m_lifetime;  // Lifetime
     VVarAttrClocker m_attrClocker;
     MTaskIdSet m_mtaskIds;  // MTaskID's that read or write this var
+    AstIface* m_sensIfacep = nullptr;  // Interface type to which reads from this var are sensitive
     int m_pinNum = 0;  // For XML, if non-zero the connection pin number
     bool m_ansi : 1;  // Params or pins declared in the module header, rather than the body
     bool m_declTyped : 1;  // Declared as type (for dedup check)
@@ -1742,7 +1743,6 @@ class AstVar final : public AstNode {
     bool m_usedClock : 1;  // Signal used as a clock
     bool m_usedParam : 1;  // Parameter is referenced (on link; later signals not setup)
     bool m_usedLoopIdx : 1;  // Variable subject of for unrolling
-    bool m_usedVirtIface : 1;  // Signal used through a virtual interface
     bool m_funcLocal : 1;  // Local variable for a function
     bool m_funcLocalSticky : 1;  // As m_funcLocal but remains set if var is moved to a static
     bool m_funcReturn : 1;  // Return variable for a function
@@ -1784,7 +1784,6 @@ class AstVar final : public AstNode {
         m_usedClock = false;
         m_usedParam = false;
         m_usedLoopIdx = false;
-        m_usedVirtIface = false;
         m_sigPublic = false;
         m_sigModPublic = false;
         m_sigUserRdPublic = false;
@@ -1866,6 +1865,8 @@ class AstVar final : public AstNode {
         dtypeFrom(examplep);
     }
     ASTGEN_MEMBERS_AstVar;
+    void cloneRelink() override;
+    const char* broken() const override;
     void dump(std::ostream& str) const override;
     bool same(const AstNode* samep) const override;
     string name() const override VL_MT_STABLE VL_MT_SAFE { return m_name; }  // * = Var name
@@ -1913,6 +1914,7 @@ class AstVar final : public AstNode {
     }
     void ansi(bool flag) { m_ansi = flag; }
     void declTyped(bool flag) { m_declTyped = flag; }
+    void sensIfacep(AstIface* nodep) { m_sensIfacep = nodep; }
     void attrClocker(VVarAttrClocker flag) { m_attrClocker = flag; }
     void attrFileDescr(bool flag) { m_fileDescr = flag; }
     void attrScClocked(bool flag) { m_scClocked = flag; }
@@ -1923,7 +1925,6 @@ class AstVar final : public AstNode {
     void usedClock(bool flag) { m_usedClock = flag; }
     void usedParam(bool flag) { m_usedParam = flag; }
     void usedLoopIdx(bool flag) { m_usedLoopIdx = flag; }
-    void usedVirtIface(bool flag) { m_usedVirtIface = flag; }
     void sigPublic(bool flag) { m_sigPublic = flag; }
     void sigModPublic(bool flag) { m_sigModPublic = flag; }
     void sigUserRdPublic(bool flag) {
@@ -2016,7 +2017,6 @@ class AstVar final : public AstNode {
     bool isUsedClock() const { return m_usedClock; }
     bool isUsedParam() const { return m_usedParam; }
     bool isUsedLoopIdx() const { return m_usedLoopIdx; }
-    bool isUsedVirtIface() const { return m_usedVirtIface; }
     bool isSc() const VL_MT_SAFE { return m_sc; }
     bool isScQuad() const;
     bool isScBv() const;
@@ -2044,6 +2044,7 @@ class AstVar final : public AstNode {
     bool attrSFormat() const { return m_attrSFormat; }
     bool attrSplitVar() const { return m_attrSplitVar; }
     bool attrIsolateAssign() const { return m_attrIsolateAssign; }
+    AstIface* sensIfacep() const { return m_sensIfacep; }
     VVarAttrClocker attrClocker() const { return m_attrClocker; }
     string verilogKwd() const override;
     void lifetime(const VLifetime& flag) { m_lifetime = flag; }

src/V3AstNodes.cpp

@@ -2168,6 +2168,13 @@ int AstVarRef::instrCount() const {
     // Otherwise as a load/store
     return widthInstrs() * (access().isReadOrRW() ? INSTR_COUNT_LD : 1);
 }
+void AstVar::cloneRelink() {
+    if (m_sensIfacep && m_sensIfacep->clonep()) m_sensIfacep = m_sensIfacep->clonep();
+}
+const char* AstVar::broken() const {
+    BROKEN_RTN(m_sensIfacep && !m_sensIfacep->brokeExists());
+    return nullptr;
+}
 void AstVar::dump(std::ostream& str) const {
     this->AstNode::dump(str);
     if (isSc()) str << " [SC]";

src/V3Const.cpp

@@ -2691,7 +2691,7 @@ class ConstVisitor final : public VNVisitor {
                      && m_doNConst
                      && v3Global.opt.fConst()
                      // Default value, not a "known" constant for this usage
-                     && !nodep->varp()->isClassMember() && !nodep->varp()->isUsedVirtIface()
+                     && !nodep->varp()->isClassMember() && !nodep->varp()->sensIfacep()
                      && !(nodep->varp()->isFuncLocal() && nodep->varp()->isNonOutput())
                      && !nodep->varp()->noSubst() && !nodep->varp()->isSigPublic())
                     || nodep->varp()->isParam())) {

src/V3Dead.cpp

@@ -361,7 +361,7 @@ class DeadVisitor final : public VNVisitor {
     }
     bool mightElimVar(AstVar* nodep) const {
         if (nodep->isSigPublic()) return false;  // Can't elim publics!
-        if (nodep->isIO() || nodep->isClassMember() || nodep->isUsedVirtIface()) return false;
+        if (nodep->isIO() || nodep->isClassMember() || nodep->sensIfacep()) return false;
         if (nodep->isTemp() && !nodep->isTrace()) return true;
         return m_elimUserVars;  // Post-Trace can kill most anything
     }

src/V3Gate.cpp

@@ -163,7 +163,7 @@ class GateGraph final : public V3Graph {
             UINFO(6, "New vertex " << vscp << endl);
             vVtxp = new GateVarVertex{this, vscp};
             vscp->user1p(vVtxp);
-            if (vscp->varp()->isUsedVirtIface()) {
+            if (vscp->varp()->sensIfacep()) {
                 // Can be used in a class method, which cannot be tracked statically
                 vVtxp->clearReducibleAndDedupable("VirtIface");
                 vVtxp->setConsumed("VirtIface");

src/V3Global.h

@@ -112,6 +112,7 @@ class V3Global final {
     bool m_dpi = false;  // Need __Dpi include files
     bool m_hasEvents = false;  // Design uses SystemVerilog named events
     bool m_hasClasses = false;  // Design uses SystemVerilog classes
+    bool m_hasVirtIfaces = false;  // Design uses virtual interfaces
     bool m_usesProbDist = false;  // Uses $dist_*
     bool m_usesStdPackage = false;  // Design uses the std package
     bool m_usesTiming = false;  // Design uses timing constructs
@@ -162,6 +163,8 @@ class V3Global final {
     void setHasEvents() { m_hasEvents = true; }
     bool hasClasses() const { return m_hasClasses; }
     void setHasClasses() { m_hasClasses = true; }
+    bool hasVirtIfaces() const { return m_hasVirtIfaces; }
+    void setHasVirtIfaces() { m_hasVirtIfaces = true; }
     bool usesProbDist() const { return m_usesProbDist; }
     void setUsesProbDist() { m_usesProbDist = true; }
     bool usesStdPackage() const { return m_usesStdPackage; }

src/V3Life.cpp

@@ -137,7 +137,7 @@ class LifeBlock final {
     void checkRemoveAssign(const LifeMap::iterator& it) {
         const AstVar* const varp = it->first->varp();
         LifeVarEntry* const entp = &(it->second);
-        if (!varp->isSigPublic() && !varp->isUsedVirtIface()) {
+        if (!varp->isSigPublic() && !varp->sensIfacep()) {
             // Rather than track what sigs AstUCFunc/AstUCStmt may change,
             // we just don't optimize any public sigs
             // Check the var entry, and remove if appropriate
@@ -178,7 +178,7 @@ class LifeBlock final {
         const auto pair = m_map.emplace(nodep, LifeVarEntry::CONSUMED{});
         if (!pair.second) {
             if (AstConst* const constp = pair.first->second.constNodep()) {
-                if (!varrefp->varp()->isSigPublic() && !varrefp->varp()->isUsedVirtIface()) {
+                if (!varrefp->varp()->isSigPublic() && !varrefp->varp()->sensIfacep()) {
                     // Aha, variable is constant; substitute in.
                     // We'll later constant propagate
                     UINFO(4, "     replaceconst: " << varrefp << endl);

src/V3Localize.cpp

@@ -166,7 +166,7 @@ class LocalizeVisitor final : public VNVisitor {
             && !nodep->varp()->isFuncLocal()  // Not already a function local (e.g.: argument)
             && !nodep->varp()->isStatic()  // Not a static variable
             && !nodep->varp()->isClassMember()  // Statically exists in design hierarchy
-            && !nodep->varp()->isUsedVirtIface()  // Not used through a virtual interface
+            && !nodep->varp()->sensIfacep()  // Not sensitive to an interface
             && !nodep->varp()->valuep()  // Does not have an initializer
         ) {
             UINFO(4, "Consider for localization: " << nodep << endl);

src/V3Sched.cpp

@@ -508,16 +508,16 @@ struct TriggerKit {
         m_funcp->stmtsp()->addHereThisAsNext(callp->makeStmt());
     }
 
-    // Utility to set then clear the dpiExportTrigger trigger
-    void addDpiExportTriggerAssignment(AstVarScope* dpiExportTriggerVscp, uint32_t index) const {
-        FileLine* const flp = dpiExportTriggerVscp->fileline();
+    // Utility to set then clear an extra trigger
+    void addExtraTriggerAssignment(AstVarScope* extraTriggerVscp, uint32_t index) const {
+        FileLine* const flp = extraTriggerVscp->fileline();
         AstVarRef* const vrefp = new AstVarRef{flp, m_vscp, VAccess::WRITE};
         AstCMethodHard* const callp = new AstCMethodHard{flp, vrefp, "set"};
         callp->addPinsp(new AstConst{flp, index});
-        callp->addPinsp(new AstVarRef{flp, dpiExportTriggerVscp, VAccess::READ});
+        callp->addPinsp(new AstVarRef{flp, extraTriggerVscp, VAccess::READ});
         callp->dtypeSetVoid();
         AstNode* const stmtp = callp->makeStmt();
-        stmtp->addNext(new AstAssign{flp, new AstVarRef{flp, dpiExportTriggerVscp, VAccess::WRITE},
+        stmtp->addNext(new AstAssign{flp, new AstVarRef{flp, extraTriggerVscp, VAccess::WRITE},
                                      new AstConst{flp, AstConst::BitFalse{}}});
         m_funcp->stmtsp()->addHereThisAsNext(stmtp);
     }
@@ -576,6 +576,17 @@ class ExtraTriggers final {
     const string& description(size_t index) const { return m_descriptions[index]; }
 };
 
+//============================================================================
+// Helper that creates virtual interface trigger resets
+
+void addVirtIfaceTriggerAssignments(const VirtIfaceTriggers& virtIfaceTriggers,
+                                    size_t vifTriggerIndex, const TriggerKit& actTrig) {
+    for (const auto& p : virtIfaceTriggers) {
+        actTrig.addExtraTriggerAssignment(p.second, vifTriggerIndex);
+        ++vifTriggerIndex;
+    }
+}
+
 //============================================================================
 // Create a TRIGGERVEC and the related TriggerKit for the given AstSenTree vector
 
@@ -808,7 +819,8 @@ void createSettle(AstNetlist* netlistp, AstCFunc* const initFuncp, SenExprBuilde
 // Order the replicated combinational logic to create the 'ico' region
 
 AstNode* createInputCombLoop(AstNetlist* netlistp, AstCFunc* const initFuncp,
-                             SenExprBuilder& senExprBuilder, LogicByScope& logic) {
+                             SenExprBuilder& senExprBuilder, LogicByScope& logic,
+                             const VirtIfaceTriggers& virtIfaceTriggers) {
     // Nothing to do if no combinational logic is sensitive to top level inputs
     if (logic.empty()) return nullptr;
 
@@ -834,15 +846,20 @@ AstNode* createInputCombLoop(AstNetlist* netlistp, AstCFunc* const initFuncp,
     const size_t dpiExportTriggerIndex = dpiExportTriggerVscp
                                              ? extraTriggers.allocate("DPI export trigger")
                                              : std::numeric_limits<unsigned>::max();
+    const size_t firstVifTriggerIndex = extraTriggers.size();
+    for (const auto& p : virtIfaceTriggers) {
+        extraTriggers.allocate("virtual interface: " + p.first->name());
+    }
 
     // Gather the relevant sensitivity expressions and create the trigger kit
     const auto& senTreeps = getSenTreesUsedBy({&logic});
     const TriggerKit& trig
         = createTriggers(netlistp, initFuncp, senExprBuilder, senTreeps, "ico", extraTriggers);
 
     if (dpiExportTriggerVscp) {
-        trig.addDpiExportTriggerAssignment(dpiExportTriggerVscp, dpiExportTriggerIndex);
+        trig.addExtraTriggerAssignment(dpiExportTriggerVscp, dpiExportTriggerIndex);
     }
+    addVirtIfaceTriggerAssignments(virtIfaceTriggers, firstVifTriggerIndex, trig);
 
     // Remap sensitivities
     remapSensitivities(logic, trig.m_map);
@@ -859,6 +876,8 @@ AstNode* createInputCombLoop(AstNetlist* netlistp, AstCFunc* const initFuncp,
     AstSenTree* const dpiExportTriggered
         = dpiExportTriggerVscp ? createTriggerSenTree(netlistp, trig.m_vscp, dpiExportTriggerIndex)
                                : nullptr;
+    const auto& vifTriggered
+        = virtIfaceTriggers.makeIfaceToSensMap(netlistp, firstVifTriggerIndex, trig.m_vscp);
 
     // Create and Order the body function
     AstCFunc* const icoFuncp
@@ -869,6 +888,10 @@ AstNode* createInputCombLoop(AstNetlist* netlistp, AstCFunc* const initFuncp,
                                  out.push_back(inputChanged);
                              }
                              if (varp->isWrittenByDpi()) out.push_back(dpiExportTriggered);
+                             if (vscp->varp()->sensIfacep()) {
+                                 const auto it = vifTriggered.find(vscp->varp()->sensIfacep());
+                                 if (it != vifTriggered.end()) out.push_back(it->second);
+                             }
                          });
     splitCheck(icoFuncp);
 
@@ -1070,6 +1093,21 @@ void createEval(AstNetlist* netlistp,  //
 
 }  // namespace
 
+//============================================================================
+// Helper that builds virtual interface trigger sentrees
+
+VirtIfaceTriggers::IfaceSensMap
+VirtIfaceTriggers::makeIfaceToSensMap(AstNetlist* const netlistp, size_t vifTriggerIndex,
+                                      AstVarScope* trigVscp) const {
+    std::map<const AstIface*, AstSenTree*> ifaceToSensMap;
+    for (const auto& p : *this) {
+        ifaceToSensMap.emplace(
+            std::make_pair(p.first, createTriggerSenTree(netlistp, trigVscp, vifTriggerIndex)));
+        ++vifTriggerIndex;
+    }
+    return ifaceToSensMap;
+}
+
 //============================================================================
 // Top level entry-point to scheduling
 
@@ -1080,7 +1118,10 @@ void schedule(AstNetlist* netlistp) {
         V3Stats::addStat("Scheduling, " + name, size);
     };
 
-    // Step 0. Prepare timing-related logic and external domains
+    // Step 0. Prepare external domains for timing and virtual interfaces
+    // Create extra triggers for virtual interfaces
+    const auto& virtIfaceTriggers = makeVirtIfaceTriggers(netlistp);
+    // Prepare timing-related logic and external domains
     TimingKit timingKit = prepareTiming(netlistp);
 
     // Step 1. Gather and classify all logic in the design
@@ -1145,8 +1186,8 @@ void schedule(AstNetlist* netlistp) {
     }
 
     // Step 7: Create input combinational logic loop
-    AstNode* const icoLoopp
-        = createInputCombLoop(netlistp, initp, senExprBuilder, logicReplicas.m_ico);
+    AstNode* const icoLoopp = createInputCombLoop(netlistp, initp, senExprBuilder,
+                                                  logicReplicas.m_ico, virtIfaceTriggers);
     if (v3Global.opt.stats()) V3Stats::statsStage("sched-create-ico");
 
     // Step 8: Create the pre/act/nba triggers
@@ -1157,6 +1198,10 @@ void schedule(AstNetlist* netlistp) {
     const size_t dpiExportTriggerIndex = dpiExportTriggerVscp
                                              ? extraTriggers.allocate("DPI export trigger")
                                              : std::numeric_limits<unsigned>::max();
+    const size_t firstVifTriggerIndex = extraTriggers.size();
+    for (const auto& p : virtIfaceTriggers) {
+        extraTriggers.allocate("virtual interface: " + p.first->name());
+    }
 
     const auto& senTreeps = getSenTreesUsedBy({&logicRegions.m_pre,  //
                                                &logicRegions.m_act,  //
@@ -1171,8 +1216,9 @@ void schedule(AstNetlist* netlistp) {
     if (timingKit.m_postUpdates) actTrig.m_funcp->addStmtsp(timingKit.m_postUpdates);
 
     if (dpiExportTriggerVscp) {
-        actTrig.addDpiExportTriggerAssignment(dpiExportTriggerVscp, dpiExportTriggerIndex);
+        actTrig.addExtraTriggerAssignment(dpiExportTriggerVscp, dpiExportTriggerIndex);
     }
+    addVirtIfaceTriggerAssignments(virtIfaceTriggers, firstVifTriggerIndex, actTrig);
 
     AstVarScope* const actTrigVscp = actTrig.m_vscp;
     AstVarScope* const preTrigVscp = scopeTopp->createTempLike("__VpreTriggered", actTrigVscp);
@@ -1224,12 +1270,19 @@ void schedule(AstNetlist* netlistp) {
               ? createTriggerSenTree(netlistp, actTrig.m_vscp, dpiExportTriggerIndex)
               : nullptr;
 
+    const auto& vifTriggeredAct
+        = virtIfaceTriggers.makeIfaceToSensMap(netlistp, firstVifTriggerIndex, actTrig.m_vscp);
+
     AstCFunc* const actFuncp = V3Order::order(
         netlistp, {&logicRegions.m_pre, &logicRegions.m_act, &logicReplicas.m_act}, trigToSenAct,
         "act", false, false, [&](const AstVarScope* vscp, std::vector<AstSenTree*>& out) {
             auto it = actTimingDomains.find(vscp);
             if (it != actTimingDomains.end()) out = it->second;
             if (vscp->varp()->isWrittenByDpi()) out.push_back(dpiExportTriggeredAct);
+            if (vscp->varp()->sensIfacep()) {
+                const auto it = vifTriggeredAct.find(vscp->varp()->sensIfacep());
+                if (it != vifTriggeredAct.end()) out.push_back(it->second);
+            }
         });
     splitCheck(actFuncp);
     if (v3Global.opt.stats()) V3Stats::statsStage("sched-create-act");
@@ -1253,6 +1306,8 @@ void schedule(AstNetlist* netlistp) {
             = dpiExportTriggerVscp
                   ? createTriggerSenTree(netlistp, trigVscp, dpiExportTriggerIndex)
                   : nullptr;
+        const auto& vifTriggered
+            = virtIfaceTriggers.makeIfaceToSensMap(netlistp, firstVifTriggerIndex, trigVscp);
 
         const auto& timingDomains = timingKit.remapDomains(trigMap);
         AstCFunc* const funcp = V3Order::order(
@@ -1261,6 +1316,10 @@ void schedule(AstNetlist* netlistp) {
                 auto it = timingDomains.find(vscp);
                 if (it != timingDomains.end()) out = it->second;
                 if (vscp->varp()->isWrittenByDpi()) out.push_back(dpiExportTriggered);
+                if (vscp->varp()->sensIfacep()) {
+                    const auto it = vifTriggered.find(vscp->varp()->sensIfacep());
+                    if (it != vifTriggered.end()) out.push_back(it->second);
+                }
             });
 
         // Create the trigger dumping function, which is the same as act trigger