verilator/src/V3WidthCommit.h

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Cleanup stage in V3Width
//
// Code available from: https://verilator.org
//
//*************************************************************************
//
// Copyright 2003-2020 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.
//
//*************************************************************************

#ifndef _V3WIDTHCOMMIT_H_
#define _V3WIDTHCOMMIT_H_ 1

#include "config_build.h"
#include "verilatedos.h"

#include "V3Error.h"
#include "V3Ast.h"

#ifndef _V3WIDTH_CPP_
# error "V3WidthCommit for V3Width internal use only"
#endif

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

/// Remove all $signed, $unsigned, we're done with them.
/// This step is only called on real V3Width, not intermediate e.g. widthParams

class WidthRemoveVisitor : public AstNVisitor {
private:
    // VISITORS
    virtual void visit(AstSigned* nodep) {
        VL_DO_DANGLING(replaceWithSignedVersion(nodep, nodep->lhsp()->unlinkFrBack()), nodep);
    }
    virtual void visit(AstUnsigned* nodep) {
        VL_DO_DANGLING(replaceWithSignedVersion(nodep, nodep->lhsp()->unlinkFrBack()), nodep);
    }
    virtual void visit(AstNode* nodep) {
        iterateChildren(nodep);
    }
    void replaceWithSignedVersion(AstNode* nodep, AstNode* newp) {
        UINFO(6," Replace "<<nodep<<" w/ "<<newp<<endl);
        nodep->replaceWith(newp);
        newp->dtypeFrom(nodep);
        VL_DO_DANGLING(pushDeletep(nodep), nodep);
    }
public:
    // CONSTRUCTORS
    WidthRemoveVisitor() {}
    virtual ~WidthRemoveVisitor() {}
    AstNode* mainAcceptEdit(AstNode* nodep) {
        return iterateSubtreeReturnEdits(nodep);
    }
};

//######################################################################
// Now that all widthing is complete,
// Copy all width() to widthMin().  V3Const expects this

class WidthCommitVisitor : public AstNVisitor {
    // NODE STATE
    // AstVar::user1p           -> bool, processed
    AstUser1InUse       m_inuser1;

public:
    // METHODS
    static AstConst* newIfConstCommitSize(AstConst* nodep) {
        if (((nodep->dtypep()->width() != nodep->num().width())
             || !nodep->num().sized())
            && !nodep->num().isString()) {  // Need to force the number from unsized to sized
            V3Number num (nodep, nodep->dtypep()->width());
            num.opAssign(nodep->num());
            num.isSigned(nodep->isSigned());
            AstConst* newp = new AstConst(nodep->fileline(), num);
            newp->dtypeFrom(nodep);
            return newp;
        } else {
            return NULL;
        }
    }

private:
    // METHODS
    void editDType(AstNode* nodep) {
        // Edit dtypes for this node
        nodep->dtypep(editOneDType(nodep->dtypep()));
    }
    AstNodeDType* editOneDType(AstNodeDType* nodep) {
        // See if the dtype/refDType can be converted to a standard one
        // This reduces the number of dtypes in the system, and since
        // dtypep() figures into sameTree() results in better optimizations
        if (!nodep) return NULL;
        // Recurse to handle the data type, as may change the size etc of this type
        if (!nodep->user1()) iterate(nodep);
        // Look for duplicate
        if (AstBasicDType* bdtypep = VN_CAST(nodep, BasicDType)) {
            AstBasicDType* newp = nodep->findInsertSameDType(bdtypep);
            if (newp != bdtypep && debug()>=9) {
                UINFO(9,"dtype replacement "); nodep->dumpSmall(cout);
                cout<<"  ---->  "; newp->dumpSmall(cout); cout<<endl;
            }
            return newp;
        }
        return nodep;
    }
    // VISITORS
    virtual void visit(AstConst* nodep) {
        UASSERT_OBJ(nodep->dtypep(), nodep, "No dtype");
        iterate(nodep->dtypep());  // Do datatype first
        if (AstConst* newp = newIfConstCommitSize(nodep)) {
            nodep->replaceWith(newp);
            AstNode* oldp = nodep; nodep = newp;
            //if (debug()>4) oldp->dumpTree(cout, "  fixConstSize_old: ");
            //if (debug()>4) newp->dumpTree(cout, "              _new: ");
            VL_DO_DANGLING(pushDeletep(oldp), oldp);
        }
        editDType(nodep);
    }
    virtual void visit(AstNodeDType* nodep) {
        visitIterateNodeDType(nodep);
    }
    virtual void visit(AstNodeUOrStructDType* nodep) {
        if (nodep->user1SetOnce()) return;  // Process once
        visitIterateNodeDType(nodep);
        nodep->clearCache();
    }
    virtual void visit(AstParamTypeDType* nodep) {
        if (nodep->user1SetOnce()) return;  // Process once
        visitIterateNodeDType(nodep);
        // Move to type table as all dtype pointers must resolve there
        nodep->unlinkFrBack();  // Make non-child
        v3Global.rootp()->typeTablep()->addTypesp(nodep);
    }
    void visitIterateNodeDType(AstNodeDType* nodep) {
        // Rather than use dtypeChg which may make new nodes, we simply edit in place,
        // as we don't need to preserve any widthMin's, and every dtype with the same width
        // gets an identical edit.
        if (nodep->user1SetOnce()) return;  // Process once
        nodep->widthMinFromWidth();
        // Too late to any unspecified sign to be anything but unsigned
        if (nodep->numeric().isNosign()) nodep->numeric(AstNumeric::UNSIGNED);
        iterateChildren(nodep);
        nodep->virtRefDTypep(editOneDType(nodep->virtRefDTypep()));
        nodep->virtRefDType2p(editOneDType(nodep->virtRefDType2p()));
    }
    virtual void visit(AstNodePreSel* nodep) {  // LCOV_EXCL_LINE
        // This check could go anywhere after V3Param
        nodep->v3fatalSrc("Presels should have been removed before this point");
    }
    virtual void visit(AstNode* nodep) {
        iterateChildren(nodep);
        editDType(nodep);
    }
public:
    // CONSTRUCTORS
    explicit WidthCommitVisitor(AstNetlist* nodep) {
        // Were changing widthMin's, so the table is now somewhat trashed
        nodep->typeTablep()->clearCache();
        iterate(nodep);
        // Don't want to repairCache, as all needed nodes have been added back in
        // a repair would prevent dead nodes from being detected
    }
    virtual ~WidthCommitVisitor() {}
};

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

#endif  // Guard