verilator/src/V3Descope.cpp

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Rename scope references to module-local references
//
// Code available from: http://www.veripool.org/verilator
//
//*************************************************************************
//
// Copyright 2003-2013 by Wilson Snyder.  This program is free software; you can
// redistribute it and/or modify it under the terms of either the GNU
// Lesser General Public License Version 3 or the Perl Artistic License
// Version 2.0.
//
// 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.
//
//*************************************************************************
// DESCOPE TRANSFORMATIONS:
//	All modules:
//	    Each VARREF/FUNCCALL
//		Change varref name() to be relative to current module
//		Remove varScopep()
//	    This allows for better V3Combine'ing.
//
//*************************************************************************

#include "config_build.h"
#include "verilatedos.h"
#include <cstdio>
#include <cstdarg>
#include <unistd.h>
#include <map>

#include "V3Global.h"
#include "V3Descope.h"
#include "V3Ast.h"
#include "V3EmitCBase.h"

//######################################################################

class DescopeVisitor : public AstNVisitor {
private:
    // NODE STATE
    //  Cleared entire netlist
    //   AstCFunc::user()		// bool.  Indicates processing completed
    AstUser1InUse	m_inuser1;

    // TYPES
    typedef multimap<string,AstCFunc*>	FuncMmap;

    // STATE
    AstNodeModule*	m_modp;		// Current module
    AstScope*		m_scopep;	// Current scope
    bool		m_needThis;	// Add thisp to function
    FuncMmap		m_modFuncs;	// Name of public functions added

    // 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;
	if (varp && varp->isFuncLocal()) {
	    return "";  // Relative to function, not in this
	} else if (scopep == m_scopep && m_modp->isTop()) {
	    //return "";  // Reference to scope we're in, no need to HIER-> it
	    return "vlTOPp->";
	} else if (scopep == m_scopep && !m_modp->isTop()
		   && 0) {	// We no longer thisp-> as still get ambiguation problems
	    m_needThis = true;
	    return "thisp->";  // this-> but with restricted aliasing
	} else if (scopep->aboveScopep() && scopep->aboveScopep()==m_scopep
		   && 0  // DISABLED: GCC considers the pointers ambiguous, so goes ld/store crazy
	    ) {
	    // Reference to scope of cell directly under this module, can just "cell->"
	    string name = scopep->name();
	    string::size_type pos;
	    if ((pos = name.rfind(".")) != string::npos) {
		name.erase(0,pos+1);
	    }
	    hierThisr = false;
	    return name+"->";
	} else {
	    // Reference to something else, use global variable
	    UINFO(8,"      Descope "<<scopep<<endl);
	    UINFO(8,"           to "<<scopep->name()<<endl);
	    UINFO(8,"        under "<<m_scopep->name()<<endl);
	    hierThisr = false;
	    if (!scopep->aboveScopep()) { // Top
		return "vlTOPp->";	// == "vlSymsp->TOPp->", but GCC would suspect aliases
	    } else {
		return scopep->nameVlSym()+".";
	    }
	}
    }

    void makePublicFuncWrappers() {
	// We recorded all public functions in m_modFuncs.
	// If for any given name only one function exists, we can use that function directly.
	// If multiple functions exist, we need to select the appropriate scope.
	for (FuncMmap::iterator it = m_modFuncs.begin(); it!=m_modFuncs.end(); ++it) {
	    string name = it->first;
	    AstCFunc* topFuncp = it->second;
	    FuncMmap::iterator nextIt1 = it; ++nextIt1;
	    bool moreOfSame1 =  (nextIt1!=m_modFuncs.end() && nextIt1->first == name);
	    if (moreOfSame1) {
		// Multiple functions under this name, need a wrapper function
		UINFO(6,"  Wrapping "<<name<<" multifuncs\n");
		AstCFunc* newfuncp = topFuncp->cloneTree(false);
		if (newfuncp->initsp())  newfuncp->initsp()->unlinkFrBackWithNext()->deleteTree();
		if (newfuncp->stmtsp())  newfuncp->stmtsp()->unlinkFrBackWithNext()->deleteTree();
		if (newfuncp->finalsp()) newfuncp->finalsp()->unlinkFrBackWithNext()->deleteTree();
		newfuncp->name(name);
		newfuncp->isStatic(false);
		newfuncp->addInitsp(
		    new AstCStmt(newfuncp->fileline(),
				 EmitCBaseVisitor::symClassVar()+" = this->__VlSymsp;\n"));
		newfuncp->addInitsp(new AstCStmt(newfuncp->fileline(), EmitCBaseVisitor::symTopAssign()+"\n"));
		topFuncp->addNextHere(newfuncp);
		// In the body, call each function if it matches the given scope
		for (FuncMmap::iterator eachIt = it; eachIt!=m_modFuncs.end() && eachIt->first==name; ++eachIt) {
		    it = eachIt;
		    AstCFunc* funcp = eachIt->second;
		    FuncMmap::iterator nextIt2 = eachIt; ++nextIt2;
		    bool moreOfSame =  (nextIt2!=m_modFuncs.end() && nextIt2->first == name);
		    if (!funcp->scopep()) funcp->v3fatalSrc("Not scoped");

		    UINFO(6,"     Wrapping "<<name<<" "<<funcp<<endl);
		    UINFO(6,"  at "<<newfuncp->argTypes()<<" und "<<funcp->argTypes()<<endl);
		    funcp->declPrivate(true);
		    AstNode* argsp = NULL;
		    for (AstNode* stmtp = newfuncp->argsp(); stmtp; stmtp=stmtp->nextp()) {
			if (AstVar* portp = stmtp->castVar()) {
			    if (portp->isIO() && !portp->isFuncReturn()) {
				argsp = argsp->addNextNull(new AstVarRef(portp->fileline(), portp,
									 portp->isOutput()));
			    }
			}
		    }

		    AstNode* returnp = new AstCReturn (funcp->fileline(),
						       new AstCCall (funcp->fileline(),
								     funcp,
								     argsp));

		    if (moreOfSame) {
			AstIf* ifp = new AstIf (funcp->fileline(),
						new AstEq(funcp->fileline(),
							  new AstCMath(funcp->fileline(),
								       "this", 64),
							  new AstCMath(funcp->fileline(),
								       string("&(")
								       +funcp->scopep()->nameVlSym()
								       +")", 64)),
						returnp, NULL);
			newfuncp->addStmtsp(ifp);
		    } else {
			newfuncp->addStmtsp(returnp);
		    }
		}
		// Not really any way the user could do this, and we'd need to come up with some return value
		//newfuncp->addStmtsp(new AstDisplay (newfuncp->fileline(), AstDisplayType::DT_DISPLAY,
		//				      string("%%Error: ")+name+"() called with bad scope", NULL));
		//newfuncp->addStmtsp(new AstStop (newfuncp->fileline()));
		if (debug()>=9) newfuncp->dumpTree(cout,"   newfunc: ");
	    } else {
		// Only a single function under this name, we can simply rename it
		UINFO(6,"  Wrapping "<<name<<" just one "<<topFuncp<<endl);
		topFuncp->name(name);
	    }
	}
    }

    // VISITORS
    virtual void visit(AstNodeModule* nodep, AstNUser*) {
	m_modp = nodep;
	m_modFuncs.clear();
	nodep->iterateChildren(*this);
	makePublicFuncWrappers();
	m_modp = NULL;
    }
    virtual void visit(AstScope* nodep, AstNUser*) {
	m_scopep = nodep;
	nodep->iterateChildren(*this);
	m_scopep = NULL;
    }
    virtual void visit(AstVarScope* nodep, AstNUser*) {
	// Delete the varscope when we're finished
	nodep->unlinkFrBack();
	pushDeletep(nodep);
    }
    virtual void visit(AstNodeVarRef* nodep, AstNUser*) {
	nodep->iterateChildren(*this);
	// Convert the hierch name
	if (!m_scopep) nodep->v3fatalSrc("Node not under scope");
	bool hierThis;
	nodep->hiername(descopedName(nodep->varScopep()->scopep(), hierThis/*ref*/, nodep->varScopep()->varp()));
	nodep->hierThis(hierThis);
	nodep->varScopep(NULL);
    }
    virtual void visit(AstCCall* nodep, AstNUser*) {
	//UINFO(9,"       "<<nodep<<endl);
	nodep->iterateChildren(*this);
	// Convert the hierch name
	if (!m_scopep) nodep->v3fatalSrc("Node not under scope");
	if (!nodep->funcp()->scopep()) nodep->v3fatalSrc("CFunc not under scope");
	bool hierThis;
	nodep->hiername(descopedName(nodep->funcp()->scopep(), hierThis/*ref*/));
	// Can't do this, as we may have more calls later
	// nodep->funcp()->scopep(NULL);
    }
    virtual void visit(AstCFunc* nodep, AstNUser*) {
	if (!nodep->user1()) {
	    m_needThis = false;
	    nodep->iterateChildren(*this);
	    nodep->user1(true);
	    if (m_needThis) {
		nodep->v3fatalSrc("old code");
		// Really we should have more node types for backend optimization of this stuff
		string text = v3Global.opt.modPrefix() + "_" + m_modp->name()
		    +"* thisp = &("+m_scopep->nameVlSym()+");\n";
		nodep->addInitsp(new AstCStmt(nodep->fileline(), text));
	    }
	    // If it's under a scope, move it up to the top
	    if (m_scopep) {
		nodep->unlinkFrBack();
		m_modp->addStmtp(nodep);

		if (nodep->funcPublic()) {
		    // There may be multiple public functions by the same name;
		    // record for later correction or making of shells
		    m_modFuncs.insert(make_pair(nodep->name(), nodep));
		    nodep->name(m_scopep->nameDotless() +"__" + nodep->name());
		}
	    }
	}
    }
    virtual void visit(AstVar*, AstNUser*) {}
    virtual void visit(AstNode* nodep, AstNUser*) {
	nodep->iterateChildren(*this);
    }
public:
    // CONSTRUCTORS
    DescopeVisitor(AstNetlist* nodep) {
	m_modp = NULL;
	m_scopep = NULL;
	m_needThis = false;
	nodep->accept(*this);
    }
    virtual ~DescopeVisitor() {}
};

//######################################################################
// Descope class functions

void V3Descope::descopeAll(AstNetlist* nodep) {
    UINFO(2,__FUNCTION__<<": "<<endl);
    DescopeVisitor visitor (nodep);
}