Version bump

git-svn-id: file://localhost/svn/verilator/trunk/verilator@753 77ca24e4-aefa-0310-84f0-b9a241c72d87

src/V3Dead.cpp

@@ -0,0 +1,148 @@
+// $Id$
+//*************************************************************************
+// DESCRIPTION: Verilator: Dead code elimination
+//
+// Code available from: http://www.veripool.com/verilator
+//
+// AUTHORS: Wilson Snyder with Paul Wasson, Duane Gabli
+//
+//*************************************************************************
+//
+// Copyright 2003-2006 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.
+//
+// Verilator 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.
+//
+//*************************************************************************
+// DEAD TRANSFORMATIONS:
+//	Remove any unreferenced modules
+//	Remove any unreferenced variables
+//	    
+//*************************************************************************
+
+#include "config.h"
+#include <stdio.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <vector>
+
+#include "V3Global.h"
+#include "V3Dead.h"
+#include "V3Ast.h"
+
+//######################################################################
+// Dead state, as a visitor of each AstNode
+
+class DeadVisitor : public AstNVisitor {
+private:
+    // NODE STATE
+    // Entire Netlist:
+    //  AstModule::user()	-> int. Count of number of cells referencing this module.
+    //  AstVar::user()		-> int. Count of number of references
+    //  AstVarScope::user()	-> int. Count of number of references
+
+    // STATE
+    vector<AstVar*>		m_varsp;	// List of all encountered to avoid another loop through three
+    vector<AstVarScope*>	m_vscsp;	// List of all encountered to avoid another loop through three
+    bool			m_elimUserVars;	// Allow removal of user's vars
+    //int debug() { return 9; }
+
+    // METHODS
+
+    // VISITORS
+    virtual void visit(AstCell* nodep, AstNUser*) {
+	nodep->iterateChildren(*this);
+	nodep->modp()->user(nodep->modp()->user() + 1);
+    }
+    virtual void visit(AstNodeVarRef* nodep, AstNUser*) {
+	nodep->iterateChildren(*this);
+	if (nodep->varScopep()) {
+	    nodep->varScopep()->user(nodep->varScopep()->user() + 1);
+	    nodep->varScopep()->varp()->user(nodep->varScopep()->varp()->user() + 1);
+	}
+	if (nodep->varp()) {
+	    nodep->varp()->user(nodep->varp()->user() + 1);
+	}
+    }
+    virtual void visit(AstVarScope* nodep, AstNUser*) {
+	nodep->iterateChildren(*this);
+	m_vscsp.push_back(nodep);
+    }
+    virtual void visit(AstVar* nodep, AstNUser*) {
+	nodep->iterateChildren(*this);
+	m_varsp.push_back(nodep);
+    }
+
+    //-----
+    virtual void visit(AstNode* nodep, AstNUser*) {
+	nodep->iterateChildren(*this);
+    }
+
+    // METHODS
+    void deadCheckMod() {
+	// Kill any unused modules
+	for (bool retry=true; retry; ) {
+	    retry=false;
+	    AstModule* nextmodp;
+	    for (AstModule* modp = v3Global.rootp()->modulesp(); modp; modp=nextmodp) {
+		nextmodp = modp->nextp()->castModule();
+		if (modp->level()>2	&& modp->user()==0) {
+		    // > 2 because L1 is the wrapper, L2 is the top user module
+		    UINFO(4,"  Dead module "<<modp<<endl);
+		    // And its children may now be killable too....
+		    for (AstNode* nodep = modp->stmtsp(); nodep; nodep=nodep->nextp()) {
+			if (AstCell* cellp=nodep->castCell()) {
+			    cellp->modp()->user( cellp->modp()->user() - 1);
+			    retry = true;
+			}
+		    }
+		    modp->unlinkFrBack()->deleteTree(); modp=NULL;
+		}
+	    }
+	}
+    }
+    bool canElim(AstVar* nodep) {
+	return (!nodep->isSigPublic()	// Can't elim publics!
+		&& (nodep->isTemp() || nodep->isParam() || m_elimUserVars));
+    }
+    void deadCheckVar() {
+	// Delete any unused varscopes
+	for (vector<AstVarScope*>::iterator it = m_vscsp.begin(); it!=m_vscsp.end(); ++it) {
+	    if ((*it)->user() == 0 && canElim((*it)->varp())) {
+		UINFO(4,"  Dead "<<(*it)<<endl);
+		(*it)->unlinkFrBack()->deleteTree(); (*it)=NULL;
+	    }
+	}
+	for (vector<AstVar*>::iterator it = m_varsp.begin(); it!=m_varsp.end(); ++it) {
+	    if ((*it)->user() == 0 && canElim((*it))) {
+		UINFO(4,"  Dead "<<(*it)<<endl);
+		(*it)->unlinkFrBack()->deleteTree(); (*it)=NULL;
+	    }
+	}
+    }
+
+public:
+    // CONSTRUCTORS
+    DeadVisitor(AstNetlist* nodep, bool elimUserVars) {
+	m_elimUserVars = elimUserVars;
+	// Operate on whole netlist
+	AstNode::userClearTree();	// userp() used on entire tree
+	nodep->accept(*this);
+	deadCheckVar();
+	// Modules after vars, because might be vars we delete inside a mod we delete
+	deadCheckMod();
+    }
+    virtual ~DeadVisitor() {}
+};
+
+//######################################################################
+// Dead class functions
+
+void V3Dead::deadifyAll(AstNetlist* nodep, bool elimUserVars) {
+    UINFO(2,__FUNCTION__<<": "<<endl);
+    DeadVisitor visitor (nodep, elimUserVars);
+}