verilator/src/V3LinkLevel.cpp

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Resolve module/signal name references
//
// Code available from: http://www.veripool.org/verilator
//
//*************************************************************************
//
// Copyright 2003-2018 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.
//
//*************************************************************************
// LINKTOP TRANSFORMATIONS:
//	Utility functions
//	    Sort cells by depth
//	    Create new MODULE TOP with connections to below signals
//*************************************************************************

#include "config_build.h"
#include "verilatedos.h"

#include "V3Global.h"
#include "V3LinkLevel.h"
#include "V3Ast.h"

#include <algorithm>
#include <cstdarg>
#include <map>
#include <vector>

//######################################################################
// Levelizing class functions

struct CmpLevel {
    inline bool operator() (const AstNodeModule* lhsp, const AstNodeModule* rhsp) const {
	return lhsp->level() < rhsp->level();
    }
};

void V3LinkLevel::modSortByLevel() {
    // Sort modules by levels, root down to lowest children
    // Calculate levels again in case we added modules
    UINFO(2,"modSortByLevel()\n");

    // level() was computed for us in V3LinkCells

    typedef std::vector<AstNodeModule*> ModVec;

    ModVec vec;
    AstNodeModule* topp = NULL;
    for (AstNodeModule* nodep = v3Global.rootp()->modulesp(); nodep; nodep=VN_CAST(nodep->nextp(), NodeModule)) {
	if (nodep->level()<=2) {
	    if (topp) {
		nodep->v3warn(E_MULTITOP, "Unsupported: Multiple top level modules: "
			      <<nodep->prettyName()<<" and "<<topp->prettyName());
		nodep->v3warn(E_MULTITOP, "Fix, or use --top-module option to select which you want.");
	    }
	    topp = nodep;
	}
	vec.push_back(nodep);
    }
    stable_sort(vec.begin(), vec.end(), CmpLevel()); // Sort the vector
    UINFO(9,"modSortByLevel() sorted\n");  // Comment required for gcc4.6.3 / bug666
    for (ModVec::iterator it = vec.begin(); it != vec.end(); ++it) {
	AstNodeModule* nodep = *it;
	nodep->clearIter();  // Because we didn't iterate to find the node pointers, may have a stale m_iterp() needing cleanup
	nodep->unlinkFrBack();
    }
    if (v3Global.rootp()->modulesp()) v3Global.rootp()->v3fatalSrc("Unlink didn't work");
    for (ModVec::iterator it = vec.begin(); it != vec.end(); ++it) {
	AstNodeModule* nodep = *it;
	v3Global.rootp()->addModulep(nodep);
    }
    UINFO(9,"modSortByLevel() done\n");  // Comment required for gcc4.6.3 / bug666
    V3Global::dumpCheckGlobalTree("cells", false, v3Global.opt.dumpTreeLevel(__FILE__) >= 3);
}

//######################################################################
// Wrapping

void V3LinkLevel::wrapTop(AstNetlist* rootp) {
    UINFO(2,__FUNCTION__<<": "<<endl);
    // We do ONLY the top module
    AstNodeModule* oldmodp = rootp->modulesp();
    if (!oldmodp) rootp->v3fatalSrc("No module found to process");
    AstNodeModule* newmodp = new AstModule(oldmodp->fileline(), string("TOP_")+oldmodp->name());
    // Make the new module first in the list
    oldmodp->unlinkFrBackWithNext();
    newmodp->addNext(oldmodp);
    newmodp->level(1);
    newmodp->modPublic(true);
    rootp->addModulep(newmodp);

    // TODO the module creation above could be done after linkcells, but
    // the rest must be done after data type resolution
    wrapTopCell(rootp);
    wrapTopPackages(rootp);
}

void V3LinkLevel::wrapTopCell(AstNetlist* rootp) {
    AstNodeModule* newmodp = rootp->modulesp();
    if (!newmodp || !newmodp->isTop()) rootp->v3fatalSrc("No TOP module found to process");
    AstNodeModule* oldmodp = VN_CAST(newmodp->nextp(), NodeModule);
    if (!oldmodp) rootp->v3fatalSrc("No module found to process");

    // Add instance
    AstCell* cellp = new AstCell(newmodp->fileline(),
				 ((v3Global.opt.l2Name()!="") ? v3Global.opt.l2Name() : oldmodp->name()),
				 oldmodp->name(),
				 NULL, NULL, NULL);
    cellp->modp(oldmodp);
    newmodp->addStmtp(cellp);

    // Add pins
    for (AstNode* subnodep=oldmodp->stmtsp(); subnodep; subnodep = subnodep->nextp()) {
        if (AstVar* oldvarp=VN_CAST(subnodep, Var)) {
	    UINFO(8,"VARWRAP "<<oldvarp<<endl);
	    if (oldvarp->isIO()) {
		AstVar* varp = oldvarp->cloneTree(false);
		newmodp->addStmtp(varp);
		varp->sigPublic(true);	// User needs to be able to get to it...
                if (oldvarp->isIO()) {
                    oldvarp->primaryIO(false);
                    varp->primaryIO(true);
                }
                if (varp->direction().isRefOrConstRef()) {
                    varp->v3error("Unsupported: ref/const ref as primary input/output: "
                                  <<varp->prettyName());
                }
		if (varp->isIO() && v3Global.opt.systemC()) {
		    varp->sc(true);
		    // User can see trace one level down from the wrapper
		    // Avoids packing & unpacking SC signals a second time
		    varp->trace(false);
		}

		AstPin* pinp = new AstPin(oldvarp->fileline(),0,oldvarp->name(),
                                          new AstVarRef(varp->fileline(),
                                                        varp, oldvarp->isWritable()));
                // Skip length and width comp; we know it's a direct assignment
		pinp->modVarp(oldvarp);
		cellp->addPinsp(pinp);
	    }
	}
    }
}

void V3LinkLevel::wrapTopPackages(AstNetlist* rootp) {
    // Instantiate all packages under the top wrapper
    // This way all later SCOPE based optimizations can ignore packages
    AstNodeModule* newmodp = rootp->modulesp();
    if (!newmodp || !newmodp->isTop()) rootp->v3fatalSrc("No TOP module found to process");
    for (AstNodeModule* modp = rootp->modulesp(); modp; modp=VN_CAST(modp->nextp(), NodeModule)) {
        if (VN_IS(modp, Package)) {
	    AstCell* cellp = new AstCell(modp->fileline(),
					 // Could add __03a__03a="::" to prevent conflict
					 // with module names/"v"
					 modp->name(),
					 modp->name(),
					 NULL, NULL, NULL);
	    cellp->modp(modp);
	    newmodp->addStmtp(cellp);
	}
    }
}