From e8ff191a17e6af6510699c197ce2e05941339746 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Mon, 20 Jan 2020 13:27:27 -0500
Subject: [PATCH] Internals: Prepare for hierarchical NodeModule's. No
 functional change intended.

---
 src/V3Assert.cpp      | 15 ++++++++------
 src/V3Ast.h           |  2 +-
 src/V3Begin.cpp       | 12 +++++------
 src/V3Cdc.cpp         |  9 +++++---
 src/V3Clean.cpp       |  9 +++++---
 src/V3Clock.cpp       |  9 +++++---
 src/V3Const.cpp       |  9 +++++---
 src/V3Coverage.cpp    | 16 +++++++++------
 src/V3Dead.cpp        | 13 +++++++-----
 src/V3Depth.cpp       | 11 ++++++----
 src/V3DepthBlock.cpp  | 11 ++++++----
 src/V3Descope.cpp     | 15 ++++++++------
 src/V3EmitCSyms.cpp   |  9 +++++---
 src/V3Gate.cpp        | 11 ++++++----
 src/V3Inline.cpp      |  9 ++++++--
 src/V3LinkJump.cpp    | 19 ++++++++++-------
 src/V3LinkParse.cpp   | 17 ++++++++-------
 src/V3LinkResolve.cpp | 22 +++++++++++++-------
 src/V3Name.cpp        |  9 +++++---
 src/V3Order.cpp       |  9 +++++---
 src/V3Premit.cpp      | 11 ++++++----
 src/V3Table.cpp       | 20 ++++++++++++------
 src/V3Task.cpp        | 15 +++++++++-----
 src/V3Tristate.cpp    | 48 ++++++++++++++++++++++++++-----------------
 src/V3Unknown.cpp     | 11 ++++++----
 25 files changed, 217 insertions(+), 124 deletions(-)

diff --git a/src/V3Assert.cpp b/src/V3Assert.cpp
index 953367966..5b158295e 100644
--- a/src/V3Assert.cpp
+++ b/src/V3Assert.cpp
@@ -356,12 +356,15 @@ private:
     }
 
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        m_modPastNum = 0;
-        //
-        iterateChildren(nodep);
-        // Reset defaults
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        unsigned origPastNum = m_modPastNum;
+        {
+            m_modp = nodep;
+            m_modPastNum = 0;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
+        m_modPastNum = origPastNum;
     }
     virtual void visit(AstBegin* nodep) {
         // This code is needed rather than a visitor in V3Begin,
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 8145a5213..ddd86aee2 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -2244,7 +2244,7 @@ public:
     AstActive* activesp() const { return VN_CAST(op3p(), Active); }  // op3 = List of i/sblocks
     // METHODS
     void addInlinesp(AstNode* nodep) { addOp1p(nodep); }
-    void addStmtp(AstNode* nodep) { addOp2p(nodep); }
+    void addStmtp(AstNode* nodep) { addNOp2p(nodep); }
     void addActivep(AstNode* nodep) { addOp3p(nodep); }
     // ACCESSORS
     virtual void name(const string& name) { m_name = name; }
diff --git a/src/V3Begin.cpp b/src/V3Begin.cpp
index ae4c4ef3f..44b8f12e6 100644
--- a/src/V3Begin.cpp
+++ b/src/V3Begin.cpp
@@ -72,7 +72,6 @@ private:
     AstNodeFTask*       m_ftaskp;       // Current function/task
     string              m_namedScope;   // Name of begin blocks above us
     string              m_unnamedScope; // Name of begin blocks, including unnamed blocks
-    int                 m_repeatNum;    // Repeat counter
     int                 m_ifDepth;      // Current if depth
 
     // METHODS
@@ -80,10 +79,12 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        m_repeatNum = 0;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstNodeFTask* nodep) {
         UINFO(8,"  "<<nodep<<endl);
@@ -232,7 +233,6 @@ public:
         m_statep = statep;
         m_modp = NULL;
         m_ftaskp = NULL;
-        m_repeatNum = 0;
         m_ifDepth = 0;
         iterate(nodep);
     }
diff --git a/src/V3Cdc.cpp b/src/V3Cdc.cpp
index 0e840947e..d23ca0706 100644
--- a/src/V3Cdc.cpp
+++ b/src/V3Cdc.cpp
@@ -609,9 +609,12 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstScope* nodep) {
         UINFO(4," SCOPE "<<nodep<<endl);
diff --git a/src/V3Clean.cpp b/src/V3Clean.cpp
index e59c909d7..963c6b2d1 100644
--- a/src/V3Clean.cpp
+++ b/src/V3Clean.cpp
@@ -177,9 +177,12 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstNodeUniop* nodep) {
         iterateChildren(nodep);
diff --git a/src/V3Clock.cpp b/src/V3Clock.cpp
index 39d6fc889..f2f311ae4 100644
--- a/src/V3Clock.cpp
+++ b/src/V3Clock.cpp
@@ -256,9 +256,12 @@ private:
     }
     virtual void visit(AstNodeModule* nodep) {
         //UINFO(4," MOD   "<<nodep<<endl);
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp= NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstScope* nodep) {
         //UINFO(4," SCOPE   "<<nodep<<endl);
diff --git a/src/V3Const.cpp b/src/V3Const.cpp
index 668fbb34c..3a383d057 100644
--- a/src/V3Const.cpp
+++ b/src/V3Const.cpp
@@ -1287,9 +1287,12 @@ private:
         iterateChildrenBackwards(nodep);
     }
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstCFunc* nodep) {
         // No ASSIGNW removals under funcs, we've long eliminated INITIALs
diff --git a/src/V3Coverage.cpp b/src/V3Coverage.cpp
index bdd8bb914..f09f8494e 100644
--- a/src/V3Coverage.cpp
+++ b/src/V3Coverage.cpp
@@ -150,12 +150,16 @@ private:
     }
     // VISITORS - BOTH
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        m_inModOff = nodep->isTop();  // Ignore coverage on top module; it's a shell we created
-        m_fileps.clear();
-        iterateChildren(nodep);
-        m_modp = NULL;
-        m_inModOff = true;
+        AstNodeModule* origModp = m_modp;
+        bool origInModOff = m_inModOff;
+        {
+            m_modp = nodep;
+            m_inModOff = nodep->isTop();  // Ignore coverage on top module; it's a shell we created
+            m_fileps.clear();
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
+        m_inModOff = origInModOff;
     }
 
     // VISITORS - TOGGLE COVERAGE
diff --git a/src/V3Dead.cpp b/src/V3Dead.cpp
index 921d18261..461b8a56d 100644
--- a/src/V3Dead.cpp
+++ b/src/V3Dead.cpp
@@ -134,12 +134,15 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        if (!nodep->dead()) {
-            iterateChildren(nodep);
-            checkAll(nodep);
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            if (!nodep->dead()) {
+                iterateChildren(nodep);
+                checkAll(nodep);
+            }
         }
-        m_modp = NULL;
+        m_modp = origModp;
     }
     virtual void visit(AstCFunc* nodep) {
         iterateChildren(nodep);
diff --git a/src/V3Depth.cpp b/src/V3Depth.cpp
index 51e1f07a0..9be333f81 100644
--- a/src/V3Depth.cpp
+++ b/src/V3Depth.cpp
@@ -84,10 +84,13 @@ private:
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
         UINFO(4," MOD   "<<nodep<<endl);
-        m_modp = nodep;
-        m_funcp = NULL;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            m_funcp = NULL;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstCFunc* nodep) {
         m_funcp = nodep;
diff --git a/src/V3DepthBlock.cpp b/src/V3DepthBlock.cpp
index 4a9abc27d..2e643e47e 100644
--- a/src/V3DepthBlock.cpp
+++ b/src/V3DepthBlock.cpp
@@ -73,10 +73,13 @@ private:
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
         UINFO(4," MOD   "<<nodep<<endl);
-        m_modp = nodep;
-        m_deepNum = 0;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            m_deepNum = 0;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstCFunc* nodep) {
         // We recurse into this.
diff --git a/src/V3Descope.cpp b/src/V3Descope.cpp
index 704896d75..a915c3840 100644
--- a/src/V3Descope.cpp
+++ b/src/V3Descope.cpp
@@ -228,12 +228,15 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        m_modFuncs.clear();
-        m_modSingleton = modIsSingleton(m_modp);
-        iterateChildren(nodep);
-        makePublicFuncWrappers();
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            m_modFuncs.clear();
+            m_modSingleton = modIsSingleton(m_modp);
+            iterateChildren(nodep);
+            makePublicFuncWrappers();
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstScope* nodep) {
         m_scopep = nodep;
diff --git a/src/V3EmitCSyms.cpp b/src/V3EmitCSyms.cpp
index f1d497a40..7ca26a7c4 100644
--- a/src/V3EmitCSyms.cpp
+++ b/src/V3EmitCSyms.cpp
@@ -270,9 +270,12 @@ class EmitCSyms : EmitCBaseVisitor {
     }
     virtual void visit(AstNodeModule* nodep) {
         nameCheck(nodep);
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstCellInline* nodep) {
         if (v3Global.opt.vpi()) {
diff --git a/src/V3Gate.cpp b/src/V3Gate.cpp
index 8f8f70d44..654aedda1 100644
--- a/src/V3Gate.cpp
+++ b/src/V3Gate.cpp
@@ -420,10 +420,13 @@ private:
         replaceAssigns();
     }
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        m_activeReducible = true;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            m_activeReducible = true;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstScope* nodep) {
         UINFO(4," SCOPE "<<nodep<<endl);
diff --git a/src/V3Inline.cpp b/src/V3Inline.cpp
index a38704c9c..ee613a254 100644
--- a/src/V3Inline.cpp
+++ b/src/V3Inline.cpp
@@ -101,6 +101,7 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
+        UASSERT_OBJ(!m_modp, nodep, "Unsupported: Recursive modules");
         m_modp = nodep;
         m_allMods.push_back(nodep);
         m_modp->user2(CIL_MAYBE);
@@ -525,8 +526,12 @@ private:
         }
     }
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        iterateChildren(nodep);
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstCell* nodep) {
         if (nodep->modp()->user1()) {  // Marked with inline request
diff --git a/src/V3LinkJump.cpp b/src/V3LinkJump.cpp
index ed97bb984..779e78b8d 100644
--- a/src/V3LinkJump.cpp
+++ b/src/V3LinkJump.cpp
@@ -49,7 +49,7 @@ private:
     AstNodeFTask*       m_ftaskp;       // Current function/task
     AstWhile*           m_loopp;        // Current loop
     bool                m_loopInc;      // In loop increment
-    int                 m_repeatNum;    // Repeat counter
+    int                 m_modRepeatNum;  // Repeat counter
     BeginStack          m_beginStack;   // All begin blocks above current node
 
     // METHODS
@@ -109,10 +109,15 @@ private:
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
         if (nodep->dead()) return;
-        m_modp = nodep;
-        m_repeatNum = 0;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        int origRepeatNum = m_modRepeatNum;
+        {
+            m_modp = nodep;
+            m_modRepeatNum = 0;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
+        m_modRepeatNum = origRepeatNum;
     }
     virtual void visit(AstNodeFTask* nodep) {
         m_ftaskp = nodep;
@@ -130,7 +135,7 @@ private:
         //    REPEAT(count,body) -> loop=count,WHILE(loop>0) { body, loop-- }
         // Note var can be signed or unsigned based on original number.
         AstNode* countp = nodep->countp()->unlinkFrBackWithNext();
-        string name = string("__Vrepeat")+cvtToStr(m_repeatNum++);
+        string name = string("__Vrepeat")+cvtToStr(m_modRepeatNum++);
         // Spec says value is integral, if negative is ignored
         AstVar* varp = new AstVar(nodep->fileline(), AstVarType::BLOCKTEMP, name,
                                   nodep->findSigned32DType());
@@ -254,7 +259,7 @@ public:
         m_ftaskp = NULL;
         m_loopp = NULL;
         m_loopInc = false;
-        m_repeatNum = 0;
+        m_modRepeatNum = 0;
         iterate(nodep);
     }
     virtual ~LinkJumpVisitor() {}
diff --git a/src/V3LinkParse.cpp b/src/V3LinkParse.cpp
index ce049fa8f..9ad4b66a1 100644
--- a/src/V3LinkParse.cpp
+++ b/src/V3LinkParse.cpp
@@ -446,14 +446,17 @@ private:
     virtual void visit(AstNodeModule* nodep) {
         V3Config::applyModule(nodep);
 
-        // Module: Create sim table for entire module and iterate
-        cleanFileline(nodep);
-        //
-        m_modp = nodep;
+        AstNodeModule* origModp = m_modp;
+        {
+            // Module: Create sim table for entire module and iterate
+            cleanFileline(nodep);
+            //
+            m_modp = nodep;
+            m_valueModp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
         m_valueModp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
-        m_valueModp = NULL;
     }
     void visitIterateNoValueMod(AstNode* nodep) {
         // Iterate a node which shouldn't have any local variables moved to an Initial
diff --git a/src/V3LinkResolve.cpp b/src/V3LinkResolve.cpp
index 122acc27a..30abedbb8 100644
--- a/src/V3LinkResolve.cpp
+++ b/src/V3LinkResolve.cpp
@@ -69,10 +69,15 @@ private:
         // Module: Create sim table for entire module and iterate
         UINFO(8,"MODULE "<<nodep<<endl);
         if (nodep->dead()) return;
-        m_modp = nodep;
-        m_senitemCvtNum = 0;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        int origSenitemCvtNum = m_senitemCvtNum;
+        {
+            m_modp = nodep;
+            m_senitemCvtNum = 0;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
+        m_senitemCvtNum = origSenitemCvtNum;
     }
     virtual void visit(AstInitial* nodep) {
         iterateChildren(nodep);
@@ -489,9 +494,12 @@ private:
         iterateChildrenBackwards(nodep);
     }
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstCell* nodep) {
         // Parent module inherits child's publicity
diff --git a/src/V3Name.cpp b/src/V3Name.cpp
index fc4694d82..aba43f7c2 100644
--- a/src/V3Name.cpp
+++ b/src/V3Name.cpp
@@ -74,9 +74,12 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     // Add __PVT__ to names of local signals
     virtual void visit(AstVar* nodep) {
diff --git a/src/V3Order.cpp b/src/V3Order.cpp
index 90356ddf1..6d4f3835c 100644
--- a/src/V3Order.cpp
+++ b/src/V3Order.cpp
@@ -1001,9 +1001,12 @@ private:
         AstNode::user4ClearTree();
     }
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstScope* nodep) {
         UINFO(4," SCOPE "<<nodep<<endl);
diff --git a/src/V3Premit.cpp b/src/V3Premit.cpp
index 93d2ec935..614c29864 100644
--- a/src/V3Premit.cpp
+++ b/src/V3Premit.cpp
@@ -199,10 +199,13 @@ private:
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
         UINFO(4," MOD   "<<nodep<<endl);
-        m_modp = nodep;
-        m_funcp = NULL;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            m_funcp = NULL;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstCFunc* nodep) {
         m_funcp = nodep;
diff --git a/src/V3Table.cpp b/src/V3Table.cpp
index 67817b87e..0d0b86e48 100644
--- a/src/V3Table.cpp
+++ b/src/V3Table.cpp
@@ -80,7 +80,8 @@ private:
     //  State cleared on each module
     AstNodeModule*      m_modp;         // Current MODULE
     int                 m_modTables;    // Number of tables created in this module
-    std::deque<AstVarScope*> m_modTableVscs;  // All tables created
+    typedef std::deque<AstVarScope*> ModTableVector;
+    ModTableVector m_modTableVscs;  // All tables created
 
     //  State cleared on each scope
     AstScope*   m_scopep;               // Current SCOPE
@@ -427,11 +428,18 @@ private:
         iterateChildren(nodep);
     }
     virtual void visit(AstNodeModule* nodep) {
-        m_modTables = 0;
-        m_modTableVscs.clear();
-        m_modp = nodep;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        int origModTables = m_modTables;
+        ModTableVector origModTableVscs = m_modTableVscs;
+        {
+            m_modp = nodep;
+            m_modTables = 0;
+            m_modTableVscs.clear();
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
+        m_modTables = origModTables;
+        m_modTableVscs = origModTableVscs;
     }
     virtual void visit(AstScope* nodep) {
         UINFO(4," SCOPE "<<nodep<<endl);
diff --git a/src/V3Task.cpp b/src/V3Task.cpp
index c3a171840..07256b07a 100644
--- a/src/V3Task.cpp
+++ b/src/V3Task.cpp
@@ -1128,11 +1128,16 @@ private:
 
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
-        m_modp = nodep;
-        m_insStmtp = NULL;
-        m_modNCalls = 0;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        int origNCalls = m_modNCalls;
+        {
+            m_modp = nodep;
+            m_insStmtp = NULL;
+            m_modNCalls = 0;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
+        m_modNCalls = origNCalls;
     }
     virtual void visit(AstTopScope* nodep) {
         m_topScopep = nodep;
diff --git a/src/V3Tristate.cpp b/src/V3Tristate.cpp
index 587aa572c..dd98f2f32 100644
--- a/src/V3Tristate.cpp
+++ b/src/V3Tristate.cpp
@@ -1306,28 +1306,38 @@ class TristateVisitor : public TristateBaseVisitor {
     }
 
     virtual void visit(AstNodeModule* nodep) {
-        UINFO(8, nodep<<endl);
-        UASSERT_OBJ(!m_graphing, nodep,
-                    "Modules under modules not supported");  // Lots of per-module state breaks
-        // Clear state
-        m_tgraph.clear();
-        m_unique = 0;
-        m_logicp = NULL;
-        m_lhsmap.clear();
-        m_modp = nodep;
-        // Walk the graph, finding all variables and tristate constructs
+        UINFO(8, nodep << endl);
+        AstNodeModule* origModp = m_modp;
+        bool origGraphing = m_graphing;
+        int origUnique = m_unique;
+        VarMap origLhsmap = m_lhsmap;
+        TristateGraph origTgraph = m_tgraph;
         {
-            m_graphing = true;
-            iterateChildren(nodep);
+            // Clear state
             m_graphing = false;
+            m_tgraph.clear();
+            m_unique = 0;
+            m_logicp = NULL;
+            m_lhsmap.clear();
+            m_modp = nodep;
+            // Walk the graph, finding all variables and tristate constructs
+            {
+                m_graphing = true;
+                iterateChildren(nodep);
+                m_graphing = false;
+            }
+            // Use graph to find tristate signals
+            m_tgraph.graphWalk(nodep);
+            // Build the LHS drivers map for this module
+            iterateChildren(nodep);
+            // Insert new logic for all tristates
+            insertTristates(nodep);
         }
-        // Use graph to find tristate signals
-        m_tgraph.graphWalk(nodep);
-        // Build the LHS drivers map for this module
-        iterateChildren(nodep);
-        // Insert new logic for all tristates
-        insertTristates(nodep);
-        m_modp = NULL;
+        m_modp = origModp;
+        m_graphing = origGraphing;
+        m_unique = origUnique;
+        m_lhsmap = origLhsmap;
+        m_tgraph = origTgraph;
     }
 
     virtual void visit(AstNodeFTask* nodep) {
diff --git a/src/V3Unknown.cpp b/src/V3Unknown.cpp
index 34d6cb2a7..c70cfdd56 100644
--- a/src/V3Unknown.cpp
+++ b/src/V3Unknown.cpp
@@ -147,10 +147,13 @@ private:
     // VISITORS
     virtual void visit(AstNodeModule* nodep) {
         UINFO(4," MOD   "<<nodep<<endl);
-        m_modp = nodep;
-        m_constXCvt = true;
-        iterateChildren(nodep);
-        m_modp = NULL;
+        AstNodeModule* origModp = m_modp;
+        {
+            m_modp = nodep;
+            m_constXCvt = true;
+            iterateChildren(nodep);
+        }
+        m_modp = origModp;
     }
     virtual void visit(AstAssignDly* nodep) {
         m_assigndlyp = nodep;