diff --git a/Changes b/Changes
index 6131c239e..cfdbffddf 100644
--- a/Changes
+++ b/Changes
@@ -5,16 +5,18 @@ indicates the contributor was also the author of the fix; Thanks!
 
 * Verilator 3.70**
 
+***  Add --debugi-<srcfile> option.  [Art Stamness]
+
 **** Fix compile issues with GCC 4.3, bug47.  [Lane Brooks]
 
 **** Fix VL_RANDom to better randomize bits.  [Art Stamness]
 
 * Verilator 3.700 2009/01/08
 
-**   Add limited support for tristate inouts.  Written by Lane Brooks.
-     This allows common pad ring and tristate-mux structures to be
-     Verilated.  See the documentation for more information on supported
-     constructs.
+**   Add limited support for tristate inouts.  Written by Lane Brooks,
+     under support by Ubixum Inc.  This allows common pad ring and
+     tristate-mux structures to be Verilated.  See the documentation for
+     more information on supported constructs.
 
 **   Add --coverage_toggle for toggle coverage analysis.
      Running coverage now requires SystemPerl 1.301 or newer.
diff --git a/bin/verilator b/bin/verilator
index 643335fc3..faf9a0e39 100755
--- a/bin/verilator
+++ b/bin/verilator
@@ -188,6 +188,8 @@ descriptions in the next sections for more information.
     -D<var>[=<value>]           Set preprocessor define
     --debug                     Enable debugging
     --debug-check               Enable debugging assertions
+    --debugi <level>            Enable debugging at a specified level
+    --debugi-<srcfile> <level>  Enable debugging a source file at a level
     --dump-tree                 Enable dumping .tree files
     -E                          Preprocess, but do not compile
     --error-limit <value>	Abort after this number of errors
@@ -375,6 +377,12 @@ internal assertions, debugging messages, and intermediate form dump files.
 Rarely needed.  Enable internal debugging assertion checks, without
 changing debug verbosity.  Enabled automatically when --debug specified.
 
+=item --debugi <level>
+=item --debugi-<srcfile> <level>
+
+Rarely needed - for developer use.  Set internal debugging level globally
+or on the specified source file to the specified level.
+
 =item --dump-tree
 
 Rarely needed.  Enable writing .tree debug files.  This is enabled with
diff --git a/src/V3Active.cpp b/src/V3Active.cpp
index cad1a7449..f9d841fd2 100644
--- a/src/V3Active.cpp
+++ b/src/V3Active.cpp
@@ -52,7 +52,11 @@
 
 class ActiveBaseVisitor : public AstNVisitor {
 protected:
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 class ActiveNamer : public ActiveBaseVisitor {
diff --git a/src/V3ActiveTop.cpp b/src/V3ActiveTop.cpp
index e53060cbd..fa7277663 100644
--- a/src/V3ActiveTop.cpp
+++ b/src/V3ActiveTop.cpp
@@ -56,7 +56,13 @@ private:
     // STATE
     AstTopScope*	m_topscopep;	// Top scope for adding sentrees under
     SenTreeFinder	m_finder;	// Find global sentree's and add them
-    //int debug() { return 9; }
+
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstTopScope* nodep, AstNUser*) {
diff --git a/src/V3AssertPre.cpp b/src/V3AssertPre.cpp
index 5d40138fd..d615bbcf5 100644
--- a/src/V3AssertPre.cpp
+++ b/src/V3AssertPre.cpp
@@ -48,9 +48,13 @@ private:
     // Reset each assertion:
     AstNodeSenItem*	m_senip;	// Last sensitivity
 
-    int debug() { return 0; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     AstSenTree* newSenTree(AstNode* nodep) {
 	// Create sentree based on clocked or default clock
 	// Return NULL for always
diff --git a/src/V3Begin.cpp b/src/V3Begin.cpp
index fc01f394b..79ad83056 100644
--- a/src/V3Begin.cpp
+++ b/src/V3Begin.cpp
@@ -47,7 +47,13 @@ private:
     AstModule*		m_modp;		// Current module
     AstNodeFTask* 	m_ftaskp;	// Current function/task
     string		m_beginScope;	// Name of begin blocks above us
-    //int debug() { return 9; }
+
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstModule* nodep, AstNUser*) {
diff --git a/src/V3Branch.cpp b/src/V3Branch.cpp
index 7521cb477..04b1ff0f2 100644
--- a/src/V3Branch.cpp
+++ b/src/V3Branch.cpp
@@ -43,9 +43,14 @@ private:
     // STATE
     int		m_likely;	// Excuses for branch likely taken
     int		m_unlikely;	// Excuses for branch likely not taken
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void reset() {
 	m_likely = false;
 	m_unlikely = false;
diff --git a/src/V3Case.cpp b/src/V3Case.cpp
index ef176e13e..4e0ff855b 100644
--- a/src/V3Case.cpp
+++ b/src/V3Case.cpp
@@ -58,7 +58,12 @@
 class CaseLintVisitor : public AstNVisitor {
 private:
     AstNodeCase* m_caseExprp;	// Under a CASE value node, if so the relevant case statement
-    //int debug() { return 9; }
+
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     virtual void visit(AstNodeCase* nodep, AstNUser*) {
 	// Detect multiple defaults
@@ -130,9 +135,13 @@ private:
     int		m_caseNoOverlapsAllCovered;	// Proven to be synopsys parallel_case compliant
     AstNode*	m_valueItem[1<<CASE_OVERLAP_WIDTH];  // For each possible value, the case branch we need
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     bool isCaseTreeFast(AstCase* nodep) {
 	int width = 0;
 	m_caseItems = 0;
diff --git a/src/V3Cast.cpp b/src/V3Cast.cpp
index 389c3c0e7..e4d73f7cf 100644
--- a/src/V3Cast.cpp
+++ b/src/V3Cast.cpp
@@ -63,9 +63,14 @@ private:
     AstUser1InUse	m_inuser1;
 
     // STATE
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void insertCast(AstNode* nodep, int needsize) {  // We'll insert ABOVE passed node
 	UINFO(4,"  NeedCast "<<nodep<<endl);
 	AstNRelinker relinkHandle;
diff --git a/src/V3Changed.cpp b/src/V3Changed.cpp
index d7813b561..0117721ba 100644
--- a/src/V3Changed.cpp
+++ b/src/V3Changed.cpp
@@ -57,9 +57,14 @@ private:
     AstModule*		m_topModp;	// Top module
     AstScope*		m_scopetopp;	// Scope under TOPSCOPE
     AstCFunc*		m_chgFuncp;	// Change function we're building
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void genChangeDet(AstVarScope* vscp) {
 #ifdef NEW_ORDERING
 	vscp->v3fatalSrc("Not applicable\n");
diff --git a/src/V3Clean.cpp b/src/V3Clean.cpp
index 9021a2bd9..ce438c671 100644
--- a/src/V3Clean.cpp
+++ b/src/V3Clean.cpp
@@ -50,14 +50,19 @@ private:
     AstUser1InUse	m_inuser1;
     AstUser2InUse	m_inuser2;
 
-    // STATE
-    AstModule* m_modp;
-    //int debug() { return 9; }
-
-    // ENUMS
+    // TYPES
     enum CleanState { UNKNOWN, CLEAN, DIRTY };
 
+    // STATE
+    AstModule* m_modp;
+
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     // Width resetting
     int  cppWidth(AstNode* nodep) {
 	if (nodep->width()<=VL_WORDSIZE) return VL_WORDSIZE;
diff --git a/src/V3ClkGater.cpp b/src/V3ClkGater.cpp
index 154b79f77..b8a4784bc 100644
--- a/src/V3ClkGater.cpp
+++ b/src/V3ClkGater.cpp
@@ -52,7 +52,11 @@
 
 class GaterBaseVisitor : public AstNVisitor {
 protected:
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
diff --git a/src/V3Clock.cpp b/src/V3Clock.cpp
index b27e1b987..e579c4630 100644
--- a/src/V3Clock.cpp
+++ b/src/V3Clock.cpp
@@ -71,9 +71,14 @@ private:
     AstSenTree*		m_lastSenp;	// Last sensitivity match, so we can detect duplicates.
     AstIf*		m_lastIfp;	// Last sensitivity if active to add more under
     int			m_stableNum;	// Number of each untilstable
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     AstVarScope* getCreateLastClk(AstVarScope* vscp) {
 	if (vscp->user1p()) return ((AstVarScope*)vscp->user1p());
 	AstVar* varp = vscp->varp();
diff --git a/src/V3Combine.cpp b/src/V3Combine.cpp
index 9bede2862..e5d74025d 100644
--- a/src/V3Combine.cpp
+++ b/src/V3Combine.cpp
@@ -58,8 +58,14 @@
 class CombBaseVisitor : public AstNVisitor {
 protected:
     // STATE
-    //int debug() { return 9; }
+
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     virtual ~CombBaseVisitor() {}
 
     //***** optimization levels
diff --git a/src/V3Const.cpp b/src/V3Const.cpp
index 24b2ad530..ee7b6f2e7 100644
--- a/src/V3Const.cpp
+++ b/src/V3Const.cpp
@@ -105,9 +105,14 @@ private:
     bool	m_expensive;	// Enable computationally expensive optimizations
     AstModule*	m_modp;		// Current module
     AstNode*	m_scopep;	// Current scope
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     bool operandConst (AstNode* nodep) {
 	return (nodep->castConst());
     }
diff --git a/src/V3Coverage.cpp b/src/V3Coverage.cpp
index 17801ed4b..b702f195f 100644
--- a/src/V3Coverage.cpp
+++ b/src/V3Coverage.cpp
@@ -54,9 +54,13 @@ private:
     FileMap	m_fileps;	// Column counts for each fileline
     string	m_beginHier;	// AstBegin hier name for user coverage points
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     const char* varIgnoreToggle(AstVar* nodep) {
 	// Return true if this shouldn't be traced
 	// See also similar rule in V3TraceDecl::varIgnoreTrace
diff --git a/src/V3CoverageJoin.cpp b/src/V3CoverageJoin.cpp
index ba1347f01..05016fe6c 100644
--- a/src/V3CoverageJoin.cpp
+++ b/src/V3CoverageJoin.cpp
@@ -53,9 +53,13 @@ private:
 
     V3Double0		m_statToggleJoins;	// Statistic tracking
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void detectDuplicates() {
 	UINFO(9,"Finding duplicates\n");
 	// Note uses user4
diff --git a/src/V3Dead.cpp b/src/V3Dead.cpp
index b15bace8b..9b4911860 100644
--- a/src/V3Dead.cpp
+++ b/src/V3Dead.cpp
@@ -81,9 +81,13 @@ private:
     AssignMap			m_assignMap;	// List of all simple assignments for each variable
     bool			m_elimUserVars;	// Allow removal of user's vars
     bool			m_sideEffect;	// Side effects discovered in assign RHS
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstCell* nodep, AstNUser*) {
diff --git a/src/V3Delayed.cpp b/src/V3Delayed.cpp
index 85f82348a..b5611f1d5 100644
--- a/src/V3Delayed.cpp
+++ b/src/V3Delayed.cpp
@@ -101,9 +101,14 @@ private:
     VarMap		m_modVarMap;	// Table of new var names created under module
     V3Double0		m_statSharedSet;// Statistic tracking
 
-    //static int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void markVarUsage(AstVar* nodep, uint32_t flags) {
 	//UINFO(4," MVU "<<flags<<" "<<nodep<<endl);
 	nodep->user1( nodep->user1() | flags );
diff --git a/src/V3Depth.cpp b/src/V3Depth.cpp
index f786308c8..ba41d75d6 100644
--- a/src/V3Depth.cpp
+++ b/src/V3Depth.cpp
@@ -51,9 +51,13 @@ private:
     int			m_depth;	// How deep in an expression
     int			m_maxdepth;	// Maximum depth in an expression
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void createDeepTemp(AstNode* nodep) {
 	UINFO(6,"  Deep  "<<nodep<<endl);
 	//if (debug()>=9) nodep->dumpTree(cout,"deep:");
diff --git a/src/V3DepthBlock.cpp b/src/V3DepthBlock.cpp
index f4b3a9c77..61b431e25 100644
--- a/src/V3DepthBlock.cpp
+++ b/src/V3DepthBlock.cpp
@@ -48,9 +48,13 @@ private:
     int			m_depth;	// How deep in an expression
     int			m_deepNum;	// How many functions made
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     AstCFunc* createDeepFunc(AstNode* nodep) {
 	AstNRelinker relinkHandle;
 	nodep->unlinkFrBack(&relinkHandle);
diff --git a/src/V3Descope.cpp b/src/V3Descope.cpp
index fea3fd56d..5d0d762ad 100644
--- a/src/V3Descope.cpp
+++ b/src/V3Descope.cpp
@@ -55,9 +55,14 @@ private:
     AstScope*		m_scopep;	// Current scope
     bool		m_needThis;	// Add thisp to function
     FuncMmap		m_modFuncs;	// Name of public functions added
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     string descopedName(AstScope* scopep, bool& hierThisr, AstVar* varp=NULL) {
 	UASSERT(scopep, "Var/Func not scoped\n");
 	hierThisr = true;
diff --git a/src/V3EmitC.cpp b/src/V3EmitC.cpp
index 5bb9dd275..3d165aa10 100644
--- a/src/V3EmitC.cpp
+++ b/src/V3EmitC.cpp
@@ -44,8 +44,14 @@ private:
     vector<AstVar*>		m_ctorVarsVec;		// All variables in constructor order
     int		m_splitSize;	// # of cfunc nodes placed into output file
     int		m_splitFilenum;	// File number being created, 0 = primary
+
 public:
-    //int debug() { return 9; }
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // ACCESSORS
     int	splitFilenum() { return m_splitFilenum; }
@@ -1680,8 +1686,7 @@ void EmitCImp::main(AstModule* modp, bool slow, bool fast) {
     string filenameNoExt = v3Global.opt.makeDir()+"/"+ modClassName(modp)+(m_fast ? "" : "__Slow");
 
     if (debug()>=5) {
-	for (int i=0;i<modp->level();i++) { cout<<"  "; }
-	UINFONL(0,"  Emitting "<<modClassName(modp)<<endl);
+	UINFO(0,"  Emitting "<<modClassName(modp)<<endl);
     }
 
     if (optSystemPerl()) {
diff --git a/src/V3EmitMk.cpp b/src/V3EmitMk.cpp
index 6b1f4e1c2..f4ffd0d0a 100644
--- a/src/V3EmitMk.cpp
+++ b/src/V3EmitMk.cpp
@@ -37,9 +37,14 @@
 
 class EmitMkVisitor : public EmitCBaseVisitor {
 public:
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void emitClassMake() {
 	// Generate the makefile
 	V3OutMkFile of (v3Global.opt.makeDir()+"/"+ v3Global.opt.prefix() + "_classes.mk");
diff --git a/src/V3EmitV.cpp b/src/V3EmitV.cpp
index 1fcc19054..139d27a3d 100644
--- a/src/V3EmitV.cpp
+++ b/src/V3EmitV.cpp
@@ -38,9 +38,14 @@
 class EmitVBaseVisitor : public EmitCBaseVisitor {
     // MEMBERS
     bool	m_suppressSemi;
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     virtual void puts(const string& str) = 0;
     virtual void putbs(const string& str) = 0;
     virtual void putsNoTracking(const string& str) = 0;
diff --git a/src/V3Expand.cpp b/src/V3Expand.cpp
index 4aeb9ad5a..6fd980972 100644
--- a/src/V3Expand.cpp
+++ b/src/V3Expand.cpp
@@ -50,9 +50,13 @@ private:
     // STATE
     AstNode*		m_stmtp;	// Current statement
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     int longOrQuadWidth (AstNode* nodep) {
 	// Return 32 or 64...
 	return (nodep->width()+(VL_WORDSIZE-1)) & ~(VL_WORDSIZE-1);
diff --git a/src/V3Gate.cpp b/src/V3Gate.cpp
index f03e66a18..9288a7e5c 100644
--- a/src/V3Gate.cpp
+++ b/src/V3Gate.cpp
@@ -48,7 +48,11 @@ typedef list<AstNodeVarRef*> GateVarRefList;
 
 class GateBaseVisitor : public AstNVisitor {
 public:
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
diff --git a/src/V3GenClk.cpp b/src/V3GenClk.cpp
index 3fe0b5a23..777a723b4 100644
--- a/src/V3GenClk.cpp
+++ b/src/V3GenClk.cpp
@@ -38,7 +38,11 @@
 
 class GenClkBaseVisitor : public AstNVisitor {
 protected:
-    //static int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
diff --git a/src/V3GraphAcyc.cpp b/src/V3GraphAcyc.cpp
index 070d184b2..062280cdf 100644
--- a/src/V3GraphAcyc.cpp
+++ b/src/V3GraphAcyc.cpp
@@ -106,7 +106,7 @@ private:
     V3EdgeFuncP		m_origEdgeFuncp;	// Function that says we follow this edge (in original graph)
     uint32_t		m_placeStep;		// Number that user() must be equal to to indicate processing
 
-    int debug() { return V3Graph::debug(); }
+    static int debug() { return V3Graph::debug(); }
 
     // METHODS
     void buildGraph (V3Graph* origGraphp);
diff --git a/src/V3GraphTest.cpp b/src/V3GraphTest.cpp
index f88fe95dc..49181da12 100644
--- a/src/V3GraphTest.cpp
+++ b/src/V3GraphTest.cpp
@@ -35,8 +35,12 @@
 class V3GraphTest {
 public:
     // ***These tests only run with DEBUG ON***
-    //static int debug() { return 9; }
-    static int debug() { return 0; }
+    static int debug() {
+	static int level = -1;
+	// Note setting just --debug will not enable this, as we exit when we run the test
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__, 0);
+	return level;
+    }
 
 protected:
     // MEMBERS
diff --git a/src/V3Hashed.cpp b/src/V3Hashed.cpp
index 5c264d3c0..8e4e39f31 100644
--- a/src/V3Hashed.cpp
+++ b/src/V3Hashed.cpp
@@ -53,7 +53,11 @@ private:
     // STATE
     V3Hash		m_lowerHash;	// Hash of the statement we're building
 
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // METHODS
     void hashNodeIterate(AstNode* nodep) {
diff --git a/src/V3Hashed.h b/src/V3Hashed.h
index 19d8dfe67..a453a55f3 100644
--- a/src/V3Hashed.h
+++ b/src/V3Hashed.h
@@ -42,7 +42,7 @@ public:
 private:
     // MEMBERS
     HashMmap		m_hashMmap;	// hashvalue -> nodes with that hash
-    int debug() { return 0; }
+
 public:
     // CONSTRUCTORS
     V3Hashed();
@@ -51,7 +51,13 @@ public:
     HashMmap& mmap() { return m_hashMmap; }	// Return map for iteration
     HashMmap::iterator begin() { return m_hashMmap.begin(); }
     HashMmap::iterator end() { return m_hashMmap.end(); }
+
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
     void clear() { m_hashMmap.clear(); }
     void hashAndInsert(AstNode* nodep);	// Hash the node, and insert into map
     bool sameNodes(AstNode* node1p, AstNode* node2p);	// After hashing, and tell if identical
diff --git a/src/V3Inline.cpp b/src/V3Inline.cpp
index 052f8a64f..f7c19f215 100644
--- a/src/V3Inline.cpp
+++ b/src/V3Inline.cpp
@@ -62,7 +62,11 @@ private:
     AstCell*		m_cellp;	// Cell being cloned
     V3Double0		m_statCells;	// Statistic tracking
 
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstNetlist* nodep, AstNUser*) {
diff --git a/src/V3Inst.cpp b/src/V3Inst.cpp
index 6f4554a56..c03a6e531 100644
--- a/src/V3Inst.cpp
+++ b/src/V3Inst.cpp
@@ -53,7 +53,11 @@ private:
     AstModule*	m_modp;		// Current module
     AstCell*	m_cellp;	// Current cell
 
-    //int debug() { return 8; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
     //int m_debug;  int debug() { return m_debug; }
 
     // VISITORS
@@ -147,7 +151,11 @@ private:
     int		m_instNum;	// Current instantiation number
     int		m_instLsb;	// Current instantiation number
 
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstCell* nodep, AstNUser*) {
diff --git a/src/V3Life.cpp b/src/V3Life.cpp
index cb08d2038..e9d27c492 100644
--- a/src/V3Life.cpp
+++ b/src/V3Life.cpp
@@ -270,7 +270,6 @@ private:
     // STATE
     LifeState*	m_statep;	// Current state
     bool	m_sideEffect;	// Side effects discovered in assign RHS
-    //static int debug() { return 9; }
 
     // LIFE MAP
     //  For each basic block, we'll make a new map of what variables that if/else is changing
@@ -278,6 +277,12 @@ private:
     LifeBlock*	m_lifep;	// Current active lifetime map for current scope
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     // VISITORS
     virtual void visit(AstVarRef* nodep, AstNUser*) {
 	// Consumption/generation of a variable,
diff --git a/src/V3LifePost.cpp b/src/V3LifePost.cpp
index 4ef200999..12e8725d0 100644
--- a/src/V3LifePost.cpp
+++ b/src/V3LifePost.cpp
@@ -44,7 +44,11 @@
 
 class LifePostBaseVisitor : public AstNVisitor {
 protected:
-//    static int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
diff --git a/src/V3Link.cpp b/src/V3Link.cpp
index ca7594522..c67444561 100644
--- a/src/V3Link.cpp
+++ b/src/V3Link.cpp
@@ -71,7 +71,11 @@ private:
     int		m_beginNum;	// Begin block number, 0=none seen
     vector<V3SymTable*> m_delSymps;	// Symbol tables to delete
 
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // METHODS
     void linkVarName (AstVarRef* nodep) {
diff --git a/src/V3LinkCells.cpp b/src/V3LinkCells.cpp
index 5ad9f0ea1..9d98240bd 100644
--- a/src/V3LinkCells.cpp
+++ b/src/V3LinkCells.cpp
@@ -96,7 +96,11 @@ private:
     LinkCellsGraph	m_graph;	// Linked graph of all cell interconnects
     LibraryVertex*	m_libVertexp;	// Vertex at root of all libraries
 
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // METHODS
     V3GraphVertex* vertex(AstModule* nodep) {
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index dcbbd557c..fe2914b7b 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -186,8 +186,12 @@ private:
     bool		m_forPrearray;		// Compress cell__[array] refs
     bool		m_forScopeCreation;	// Remove VarXRefs for V3Scope
 public:
-    static int debug() { return V3Error::debugDefault(); }
-//    static int debug() { return 9; }
+
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // CONSTRUCTORS
     LinkDotState(bool forPrearray, bool forScopeCreation) {
@@ -372,6 +376,7 @@ private:
     LinkDotBaseVertex*	m_inlineVxp;	// Vertex for current module, possibly a fake inlined one
     string		m_scope;	// Scope text
     AstBegin*		m_beginp;	// Current Begin/end block
+
     int debug() { return LinkDotState::debug(); }
 
     // VISITs
@@ -518,6 +523,7 @@ private:
     // STATE
     LinkDotState*	m_statep;	// State to pass between visitors, including symbol table
     LinkDotCellVertex*	m_cellVxp;	// Vertex for current module
+
     int debug() { return LinkDotState::debug(); }
 
     // VISITs
@@ -580,6 +586,7 @@ private:
     // STATE
     LinkDotState*	m_statep;	// State, including dotted symbol table
     LinkDotCellVertex*	m_cellVxp;	// Vertex for current module
+
     int debug() { return LinkDotState::debug(); }
 
     // METHODS
diff --git a/src/V3LinkLValue.cpp b/src/V3LinkLValue.cpp
index b1ee93d3d..d866d53ec 100644
--- a/src/V3LinkLValue.cpp
+++ b/src/V3LinkLValue.cpp
@@ -46,9 +46,12 @@ private:
     bool	m_setRefLvalue;	// Set VarRefs to lvalues for pin assignments
     AstNodeFTask* m_ftaskp;	// Function or task we're inside
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITs
     // Result handing
diff --git a/src/V3LinkParse.cpp b/src/V3LinkParse.cpp
index 58445bfde..64b9437f8 100644
--- a/src/V3LinkParse.cpp
+++ b/src/V3LinkParse.cpp
@@ -55,9 +55,13 @@ private:
     AstParseRefExp m_exp;	// Type of data we're looking for
     AstText*	m_baseTextp;	// Lowest TEXT node that needs replacement with varref
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void checkExpected(AstNode* nodep) {
 	if (m_exp != AstParseRefExp::NONE) {
 	    nodep->v3fatalSrc("Tree syntax error: Not expecting "<<nodep->type()<<" under a "<<nodep->backp()->type());
diff --git a/src/V3LinkResolve.cpp b/src/V3LinkResolve.cpp
index 5a341905b..d2971f9be 100644
--- a/src/V3LinkResolve.cpp
+++ b/src/V3LinkResolve.cpp
@@ -58,9 +58,13 @@ private:
     AstVAssert*	m_assertp;	// Current assertion
     int		m_senitemCvtNum; // Temporary signal counter
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     // VISITs
     virtual void visit(AstModule* nodep, AstNUser*) {
 	// Module: Create sim table for entire module and iterate
@@ -484,7 +488,13 @@ class LinkBotupVisitor : public AstNVisitor {
 private:
     // STATE
     AstModule*	m_modp;		// Current module
-    //int debug() { return 9; }
+
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITs
     virtual void visit(AstNetlist* nodep, AstNUser*) {
diff --git a/src/V3Localize.cpp b/src/V3Localize.cpp
index 6a08da47e..99ecc5058 100644
--- a/src/V3Localize.cpp
+++ b/src/V3Localize.cpp
@@ -49,7 +49,12 @@ protected:
     //  AstVar::user2()		-> VarFlags.  Flag state
     //  AstVar::user4()		-> AstVarRef*.  First place signal set; must be first assignment
 
-    //int debug() { return 9; }
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // TYPES
     union VarFlags {
diff --git a/src/V3Name.cpp b/src/V3Name.cpp
index e0b1038fa..64789d61c 100644
--- a/src/V3Name.cpp
+++ b/src/V3Name.cpp
@@ -53,7 +53,12 @@ private:
     // STATE
     AstModule*	m_modp;
 
-    //int debug() { return 9; }
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstModule* nodep, AstNUser*) {
diff --git a/src/V3Options.cpp b/src/V3Options.cpp
index 6261eefe4..8004ec222 100644
--- a/src/V3Options.cpp
+++ b/src/V3Options.cpp
@@ -532,7 +532,7 @@ void V3Options::parseOptsList(FileLine* fl, int argc, char** argv) {
 	    shift;
 	} // + options
 	else if (argv[i][0]=='-') {
-	    char *sw = argv[i];
+	    const char *sw = argv[i];
 	    bool flag = true;
 	    // Allow gnu -- switches
 	    if (sw[0]=='-' && sw[1]=='-') ++sw;
@@ -544,6 +544,11 @@ void V3Options::parseOptsList(FileLine* fl, int argc, char** argv) {
 		shift;
 		setDebugMode(atoi(argv[i]));
 	    }
+	    else if ( !strncmp (sw, "-debugi-", strlen("-debugi-"))) {
+		const char* src = sw+strlen("-debugi-");
+		shift;
+		setDebugSrcLevel(src, atoi(argv[i]));
+	    }
 	    else if ( !strcmp (sw, "-error-limit") ) {
 		shift;
 		m_inlineMult = atoi(argv[i]);
@@ -631,7 +636,7 @@ void V3Options::parseOptsList(FileLine* fl, int argc, char** argv) {
 	    else if ( onoff   (sw, "-underline-zero", flag/*ref*/) )	{ m_underlineZero = flag; }
 	    // Optimization
 	    else if ( !strncmp (sw, "-O", 2) ) {
-		for (char* cp=sw+strlen("-O"); *cp; ++cp) {
+		for (const char* cp=sw+strlen("-O"); *cp; ++cp) {
 		    flag = isupper(*cp);
 		    switch (tolower(*cp)) {
 		    case '0': optimize(0); break; // 0=all off
@@ -919,6 +924,27 @@ void V3Options::setDebugMode(int level) {
     cout << "Starting "<<version()<<endl;
 }
 
+void V3Options::setDebugSrcLevel(const string& srcfile, int level) {
+    DebugSrcMap::iterator iter = m_debugSrcs.find(srcfile);
+    if (iter!=m_debugSrcs.end()) {
+	iter->second = level;
+    } else {
+	m_debugSrcs.insert(make_pair(srcfile,level));
+    }
+}
+
+int V3Options::debugSrcLevel(const string& srcfile_path, int default_level) {
+    // For simplicity, calling functions can just use __FILE__ for srcfile.
+    // That means though we need to cleanup the filename from ../Foo.cpp -> Foo
+    string srcfile = V3Options::filenameNonDirExt(srcfile_path);
+    DebugSrcMap::iterator iter = m_debugSrcs.find(srcfile);
+    if (iter!=m_debugSrcs.end()) {
+	return iter->second;
+    } else {
+	return default_level;
+    }
+}
+
 void V3Options::optimize(int level) {
     // Set all optimizations to on/off
     bool flag = level > 0;
diff --git a/src/V3Options.h b/src/V3Options.h
index 1600f58fa..7a6c14218 100644
--- a/src/V3Options.h
+++ b/src/V3Options.h
@@ -26,6 +26,7 @@
 #include "verilatedos.h"
 #include <string>
 #include <vector>
+#include <map>
 #include <set>
 
 #include "V3Global.h"
@@ -75,6 +76,9 @@ typedef vector<string> V3StringList;
 typedef set<string> V3StringSet;
 
 class V3Options {
+    // TYPES
+    typedef map<string,int> DebugSrcMap;
+
     // MEMBERS (general options)
     V3OptionsImp*	m_impp;		// Slow hidden options
 
@@ -82,6 +86,7 @@ class V3Options {
     V3StringSet	m_futures;	// argument: -Wfuture- list
     V3StringSet	m_libraryFiles;	// argument: Verilog -v files
     V3StringList m_vFiles;	// argument: Verilog files to read
+    DebugSrcMap m_debugSrcs;	// argument: --debugi-<srcfile>=<level>
 
     bool	m_preprocOnly;	// main switch: -E
     bool	m_makeDepend;	// main switch: -MMD
@@ -170,6 +175,8 @@ class V3Options {
     V3Options();
     ~V3Options();
     void setDebugMode(int level);
+    void setDebugSrcLevel(const string& srcfile, int level);
+    int debugSrcLevel(const string& srcfile, int default_level=V3Error::debugDefault());
 
     // METHODS
     void addCppFile(const string& filename);
@@ -187,7 +194,7 @@ class V3Options {
     bool systemPerl() const { return m_systemPerl; }
     bool skipIdentical() const { return m_skipIdentical; }
     bool stats() const { return m_stats; }
-    bool assertOn() const { return m_assert; }  // assertOn as "assert" may be defined
+    bool assertOn() const { return m_assert; }  // assertOn as __FILE__ may be defined
     bool autoflush() const { return m_autoflush; }
     bool coverage() const { return m_coverageLine || m_coverageToggle || m_coverageUser; }
     bool coverageLine() const { return m_coverageLine; }
diff --git a/src/V3Order.cpp b/src/V3Order.cpp
index d44860ad2..678cf3e96 100644
--- a/src/V3Order.cpp
+++ b/src/V3Order.cpp
@@ -254,8 +254,6 @@ private:
     AstUser3InUse	m_inuser3;
     //AstUser4InUse	m_inuser4;	// Used only when building tree, so below
 
-    //int debug() { return 9; }
-
     // STATE
     OrderGraph		m_graph;	// Scoreboard of var usages/dependencies
     SenTreeFinder	m_finder;	// Find global sentree's and add them
@@ -296,6 +294,12 @@ private:
     enum VarUsage { VU_NONE=0, VU_CON=1, VU_GEN=2 };
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void iterateNewStmt(AstNode* nodep) {
 	if (m_scopep) {
 	    UINFO(4,"   STMT "<<nodep<<endl);
diff --git a/src/V3Param.cpp b/src/V3Param.cpp
index ac82bfcda..3caf682dd 100644
--- a/src/V3Param.cpp
+++ b/src/V3Param.cpp
@@ -70,9 +70,13 @@ private:
     LongMap	m_longMap;	// Hash of very long names to unique identity number
     int		m_longId;
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void makeSmallNames(AstModule* modp) {
 	vector<int> usedLetter; usedLetter.resize(256);
 	// Pass 1, assign first letter to each gparam's name
diff --git a/src/V3PreShell.cpp b/src/V3PreShell.cpp
index 6259a9a4f..946459d73 100644
--- a/src/V3PreShell.cpp
+++ b/src/V3PreShell.cpp
@@ -43,11 +43,15 @@ protected:
     static V3PreShellImp s_preImp;
     static V3PreProc*	s_preprocp;
 
-    //int debug() { return 9; }
-
     //---------------------------------------
     // METHODS
 
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void boot(char** env) {
 	// Create the implementation pointer
 	if (env) {}
diff --git a/src/V3Premit.cpp b/src/V3Premit.cpp
index 1c8c41cd8..8e7cd334e 100644
--- a/src/V3Premit.cpp
+++ b/src/V3Premit.cpp
@@ -60,9 +60,13 @@ private:
     AstTraceInc*	m_inTracep;	// Inside while loop, special statement additions
     bool		m_assignLhs;	// Inside assignment lhs, don't breakup extracts
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     bool assignNoTemp(AstNodeAssign* nodep) {
 	return (nodep->lhsp()->castVarRef()
 		&& !nodep->lhsp()->castVarRef()->varp()->isSc()
diff --git a/src/V3Read.h b/src/V3Read.h
index 4202fbba9..559919734 100644
--- a/src/V3Read.h
+++ b/src/V3Read.h
@@ -51,6 +51,8 @@ class V3Read {
     deque<V3Number*> m_numberps;	// Created numbers for later cleanup
     deque<FileLine>  m_lintState;	// Current lint state for save/restore
     deque<string> m_ppBuffers;		// Preprocessor->lex buffer of characters to process
+
+    // Options isn't visible, so not using debugSrcLevel
     //int debug() { return 9; }
 
 protected:
diff --git a/src/V3Scope.cpp b/src/V3Scope.cpp
index e3f34e69a..e5dd17011 100644
--- a/src/V3Scope.cpp
+++ b/src/V3Scope.cpp
@@ -56,7 +56,12 @@ private:
     AstCell*	m_aboveCellp;	// Cell that instantiates this module
     AstScope*	m_aboveScopep;	// Scope that instantiates this scope
 
-    //int debug() { return 9; }
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstNetlist* nodep, AstNUser*) {
@@ -250,9 +255,13 @@ private:
     // STATE
     AstScope*	m_scopep;	// Current scope we are building
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     // VISITORS
     virtual void visit(AstScope* nodep, AstNUser*) {
 	// Want to ignore blocks under it
diff --git a/src/V3SenTree.h b/src/V3SenTree.h
index 2054d146e..35737ed9b 100644
--- a/src/V3SenTree.h
+++ b/src/V3SenTree.h
@@ -55,8 +55,14 @@ private:
     // STATE
     AstTopScope*	m_topscopep;		// Top scope to add statement to
     vector<AstSenTree*>	m_treesp;	// List of sensitive blocks, for folding
-    //int debug() { return 9; }
+
     // VISITORS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     virtual void visit(AstModule* nodep, AstNUser*) {
 	// Only do the top
 	if (nodep->isTop()) {
diff --git a/src/V3Split.cpp b/src/V3Split.cpp
index 5fc6922bd..2f9ec017c 100644
--- a/src/V3Split.cpp
+++ b/src/V3Split.cpp
@@ -235,9 +235,13 @@ private:
     uint32_t		m_stepNum;	// Step number we need to ignore a edge in
     V3Double0		m_statSplits;	// Statistic tracking
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void scoreboardClear() {
 	//VV*****  We reset user1p() and user2p on each block!!!
 	m_inDly = false;
diff --git a/src/V3SplitAs.cpp b/src/V3SplitAs.cpp
index 5432ef5de..65e872731 100644
--- a/src/V3SplitAs.cpp
+++ b/src/V3SplitAs.cpp
@@ -44,7 +44,11 @@
 class SplitAsBaseVisitor : public AstNVisitor {
 public:
     // METHODS
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
diff --git a/src/V3Subst.cpp b/src/V3Subst.cpp
index 310becaa9..f5fa2c777 100644
--- a/src/V3Subst.cpp
+++ b/src/V3Subst.cpp
@@ -45,8 +45,11 @@
 
 class SubstBaseVisitor : public AstNVisitor {
 public:
-    static int debug() { return V3Error::debugDefault(); }
-//    static int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
@@ -80,6 +83,7 @@ class SubstVarEntry {
     SubstVarWord	m_whole;	// Data for whole vector used at once
     vector<SubstVarWord> m_words;	// Data for every word, if multi word variable
     int debug() { return SubstBaseVisitor::debug(); }
+
 public:
     // CONSTRUCTORS
     SubstVarEntry (AstVar* varp) {	// Construction for when a var is used
diff --git a/src/V3Table.cpp b/src/V3Table.cpp
index 143545cd6..a8001970d 100644
--- a/src/V3Table.cpp
+++ b/src/V3Table.cpp
@@ -54,8 +54,11 @@ class TableVisitor;
 class TableBaseVisitor : public AstNVisitor {
 public:
     // Note level 8&9 include debugging each simulation value
-//    int debug() { return 7; }
-//    int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
diff --git a/src/V3Task.cpp b/src/V3Task.cpp
index e658057f5..1e147ac7c 100644
--- a/src/V3Task.cpp
+++ b/src/V3Task.cpp
@@ -314,9 +314,14 @@ private:
     InsertMode	m_insMode;	// How to insert
     AstNode*	m_insStmtp;	// Where to insert statement
     int		m_modNCalls;	// Incrementing func # for making symbols
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     AstVarScope* createVarScope(AstVar* invarp, const string& name) {
 	// We could create under either the ref's scope or the ftask's scope.
 	// It shouldn't matter, as they are only local variables.
diff --git a/src/V3Trace.cpp b/src/V3Trace.cpp
index 3d46aed88..9b6a9d958 100644
--- a/src/V3Trace.cpp
+++ b/src/V3Trace.cpp
@@ -189,9 +189,13 @@ private:
     V3Double0		m_statUniqSigs;	// Statistic tracking
     V3Double0		m_statUniqCodes;// Statistic tracking
 
-    //int debug() { return 9; }
-
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     void detectDuplicates() {
 	UINFO(9,"Finding duplicates\n");
 	// Note uses user4
diff --git a/src/V3TraceDecl.cpp b/src/V3TraceDecl.cpp
index 2aab12de1..e5c6c2c4c 100644
--- a/src/V3TraceDecl.cpp
+++ b/src/V3TraceDecl.cpp
@@ -54,9 +54,14 @@ private:
 
     V3Double0		m_statSigs;	// Statistic tracking
     V3Double0		m_statIgnSigs;	// Statistic tracking
-    //int debug() { return 9; }
 
     // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
+
     const char* varIgnoreTrace(AstVar* nodep) {
 	// Return true if this shouldn't be traced
 	// See also similar rule in V3Coverage::varIgnoreToggle
diff --git a/src/V3Tristate.cpp b/src/V3Tristate.cpp
index 1ac0800fd..66d95b89d 100644
--- a/src/V3Tristate.cpp
+++ b/src/V3Tristate.cpp
@@ -68,7 +68,11 @@ typedef std::map<AstVar*, RefVec*> VarMap;
 
 class TristateBaseVisitor : public AstNVisitor {
 public:
-    //int debug() { return 9; }
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 };
 
 //######################################################################
diff --git a/src/V3Unknown.cpp b/src/V3Unknown.cpp
index 62a5ce9a4..c439fabe8 100644
--- a/src/V3Unknown.cpp
+++ b/src/V3Unknown.cpp
@@ -58,7 +58,12 @@ private:
     bool	m_constXCvt;	// Convert X's
     V3Double0	m_statUnkVars;	// Statistic tracking
 
-    //int debug() { return 9; }
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstModule* nodep, AstNUser*) {
diff --git a/src/V3Unroll.cpp b/src/V3Unroll.cpp
index a8c036875..839822842 100644
--- a/src/V3Unroll.cpp
+++ b/src/V3Unroll.cpp
@@ -59,7 +59,12 @@ private:
     V3Double0		m_statLoops;		// Statistic tracking
     V3Double0		m_statIters;		// Statistic tracking
 
-    //int debug() { return 9; }
+    // METHODS
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
     virtual void visit(AstModule* nodep, AstNUser*) {
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 3b459333e..860f8664c 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -81,15 +81,18 @@ private:
     AstRange*	m_cellRangep;	// Range for arrayed instantiations, NULL for normal instantiations
     AstNodeCase* m_casep;	// Current case statement CaseItem is under
 
-    //int debug() { return 9; }
-
     // CLASSES
 #define ANYSIZE 0
 
     // METHODS
-    //   Naming:  width_{output size rule}_{lhs rule}_{rhs rule}
+    static int debug() {
+	static int level = -1;
+	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
+	return level;
+    }
 
     // VISITORS
+    //   Naming:  width_{output size rule}_{lhs rule}_{rhs rule}
     // Widths: 1 bit out, lhs 1 bit
     void width_O1_L1(AstNode* nodep, AstNUser* vup);
     virtual void visit(AstLogNot* nodep, AstNUser* vup) {	width_O1_L1(nodep,vup); }
diff --git a/test_regress/driver.pl b/test_regress/driver.pl
index f97d8bf38..cdeb3fdf3 100755
--- a/test_regress/driver.pl
+++ b/test_regress/driver.pl
@@ -1,17 +1,5 @@
 #!/usr/bin/perl -w
-######################################################################
-#
-# This program is Copyright 2003-2009 by Wilson Snyder.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of either the GNU General Public License or the
-# Perl Artistic License.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
+# See copyright, etc in below POD section.
 ######################################################################
 
 require 5.006_001;
@@ -60,6 +48,9 @@ my $opt_gdb;
 my $opt_jobs = 1;
 my $opt_verbose;
 my $Opt_Verilated_Debug;
+our @Opt_Driver_Verilator_Flags;
+
+Getopt::Long::config ("pass_through");
 if (! GetOptions (
 		  "help"	=> \&usage,
 		  "debug"	=> \&debug,
@@ -75,7 +66,7 @@ if (! GetOptions (
 		  "verbose!"	=> \$opt_verbose,
 		  "<>"		=> \&parameter,
 		  )) {
-    usage();
+    die "%Error: Bad usage, try '$0 --help'\n";
 }
 
 $opt_jobs = calc_jobs() if defined $opt_jobs && $opt_jobs==0;
@@ -155,14 +146,28 @@ sub usage {
 
 sub debug {
     $Debug = 1;
+    push @Opt_Driver_Verilator_Flags, "--debug";
 }
 
+our $_Parameter_Next_Level;
+
 sub parameter {
     my $param = shift;
-    if ($param =~ /\.pl/) {
+    if ($_Parameter_Next_Level) {
+	($param =~ /^(\d+)$/)
+	    or die "%Error: Expected number following $_Parameter_Next_Level: $param\n";
+	push @Opt_Driver_Verilator_Flags, $param;
+	$_Parameter_Next_Level	= undef;
+    }
+    elsif ($param =~ /\.pl/) {
 	push @opt_tests, $param;
-    } else {
-	die "%Error: Unknown parameter: $param\n";
+    }
+    elsif ($param =~ /^--debugi/) {
+	push @Opt_Driver_Verilator_Flags, $param;
+	$_Parameter_Next_Level = $param;
+    }
+    else {
+	warn "%Error: Unknown parameter: $param\n";
     }
 }
 
@@ -379,7 +384,7 @@ sub compile {
 	$opt_gdb="gdbrun" if defined $opt_gdb;
 	my @verilator_flags = @{$param{verilator_flags}};
 	unshift @verilator_flags, "--gdb $opt_gdb" if $opt_gdb;
-	unshift @verilator_flags, "--debug" if $::Debug;
+	unshift @verilator_flags, @Opt_Driver_Verilator_Flags;
 	unshift @verilator_flags, "--x-assign unique";  # More likely to be buggy
 #	unshift @verilator_flags, "--trace";
 	if (defined $opt_optimize) {
@@ -1057,12 +1062,22 @@ Command to use to invoke VCS.
 
 =back
 
-=head1 SEE ALSO
+=head1 DISTRIBUTION
+
+The latest version is available from L<http://www.veripool.org/>.
+
+Copyright 2003-2009 by Wilson Snyder.  Verilator is free software; you can
+redistribute it and/or modify it under the terms of either the GNU Lesser
+General Public License or the Perl Artistic License.
 
 =head1 AUTHORS
 
 Wilson Snyder <wsnyder@wsnyder.org>
 
+=head1 SEE ALSO
+
+L<verilator>
+
 =cut
 
 ######################################################################