verilator/src/V3Begin.cpp

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Removal of named begin blocks
//
// Code available from: http://www.veripool.org/verilator
//
//*************************************************************************
//
// Copyright 2003-2016 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.
//
//*************************************************************************
// V3Begin's Transformations:
//
// Each module:
//	Look for BEGINs
//	    BEGIN(VAR...) -> VAR ... {renamed}
//	FOR -> WHILEs
//
// There are two scopes; named BEGINs change %m and variable scopes.
// Unnamed BEGINs change only variable, not $display("%m") scope.
//
//*************************************************************************

#include "config_build.h"
#include "verilatedos.h"
#include <cstdio>
#include <cstdarg>
#include <unistd.h>
#include <algorithm>
#include <vector>

#include "V3Global.h"
#include "V3Begin.h"
#include "V3Inst.h"
#include "V3Ast.h"

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

class BeginState {
private:
    // NODE STATE
    //Entire netlist:
    // AstNodeFTask::user1	-> bool, 1=processed
    AstUser1InUse	m_inuser1;
    bool		m_anyFuncInBegin;
public:
    BeginState() {
	m_anyFuncInBegin = false;
    }
    ~BeginState() {}
    void userMarkChanged(AstNode* nodep) {
	nodep->user1(true);
	m_anyFuncInBegin = true;
    }
    bool anyFuncInBegin() const { return m_anyFuncInBegin; }
};

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

class BeginVisitor : public AstNVisitor {
private:
    // STATE
    BeginState*		m_statep;	// Current global state
    AstNodeModule*	m_modp;		// Current module
    AstNodeFTask* 	m_ftaskp;	// Current function/task
    string		m_namedScope;	// Name of begin blocks above us
    string		m_unnamedScope;	// Name of begin blocks, including unnamed blocks
    int			m_repeatNum;	// Repeat counter
    int			m_ifDepth;	// Current if depth

    // METHODS
    static int debug() {
	static int level = -1;
	if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
	return level;
    }

    // VISITORS
    virtual void visit(AstNodeModule* nodep) {
	m_modp = nodep;
	m_repeatNum = 0;
	nodep->iterateChildren(*this);
	m_modp = NULL;
    }
    virtual void visit(AstNodeFTask* nodep) {
	UINFO(8,"  "<<nodep<<endl);
	// Rename it
	if (m_unnamedScope != "") {
	    nodep->name(m_unnamedScope+"__DOT__"+nodep->name());
	    UINFO(8,"     rename to "<<nodep->name()<<endl);
	    m_statep->userMarkChanged(nodep);
	}
	// BEGIN wrapping a function rename that function, but don't affect the inside function's variables
	// We then restart with empty naming; so that any begin's inside the function will rename inside the function
	// Process children
	string oldScope = m_namedScope;
	string oldUnnamed = m_unnamedScope;
	{
	    m_namedScope = "";
	    m_unnamedScope = "";
	    m_ftaskp = nodep;
	    nodep->iterateChildren(*this);
	    m_ftaskp = NULL;
	}
	m_namedScope = oldScope;
	m_unnamedScope = oldUnnamed;
    }
    virtual void visit(AstBegin* nodep) {
	// Begin blocks were only useful in variable creation, change names and delete
	UINFO(8,"  "<<nodep<<endl);
	string oldScope = m_namedScope;
	string oldUnnamed = m_unnamedScope;
	{
	    UINFO(8,"nname "<<m_namedScope<<endl);
	    if (nodep->name() != "") {  // Else unneeded unnamed block
		// Create data for dotted variable resolution
		string dottedname = nodep->name() + "__DOT__";  // So always found
		string::size_type pos;
		while ((pos=dottedname.find("__DOT__")) != string::npos) {
		    string ident = dottedname.substr(0,pos);
		    dottedname = dottedname.substr(pos+strlen("__DOT__"));
		    if (!nodep->unnamed()) {
			if (m_namedScope=="") m_namedScope = ident;
			else m_namedScope = m_namedScope + "__DOT__"+ident;
		    }
		    if (m_unnamedScope=="") m_unnamedScope = ident;
		    else m_unnamedScope = m_unnamedScope + "__DOT__"+ident;
		    // Create CellInline for dotted var resolution
		    if (!m_ftaskp) {
			AstCellInline* inlinep = new AstCellInline(nodep->fileline(),
								   m_unnamedScope, "__BEGIN__");
			m_modp->addInlinesp(inlinep);  // Must be parsed before any AstCells
		    }
		}
	    }

	    // Remap var names and replace lower Begins
	    nodep->stmtsp()->iterateAndNext(*this);
	    if (nodep->genforp()) nodep->v3fatalSrc("GENFORs should have been expanded earlier");
	}
	m_namedScope = oldScope;
	m_unnamedScope = oldUnnamed;

	// Cleanup
	AstNode* addsp = NULL;
	if (AstNode* stmtsp = nodep->stmtsp()) {
	    stmtsp->unlinkFrBackWithNext();
	    if (addsp) { addsp = addsp->addNextNull(stmtsp); } else { addsp = stmtsp; }
	}
	if (addsp) {
	    nodep->replaceWith(addsp);
	} else {
	    nodep->unlinkFrBack();
	}
	pushDeletep(nodep); VL_DANGLING(nodep);
    }
    virtual void visit(AstVar* nodep) {
	if (m_unnamedScope != "") {
	    // Rename it
	    nodep->name(m_unnamedScope+"__DOT__"+nodep->name());
	    m_statep->userMarkChanged(nodep);
	    // Move to module
	    nodep->unlinkFrBack();
	    if (m_ftaskp) m_ftaskp->addStmtsp(nodep);   // Begins under funcs just move into the func
	    else m_modp->addStmtp(nodep);
	}
    }
    virtual void visit(AstCell* nodep) {
	UINFO(8,"   CELL "<<nodep<<endl);
	if (m_namedScope != "") {
	    m_statep->userMarkChanged(nodep);
	    // Rename it
	    nodep->name(m_namedScope+"__DOT__"+nodep->name());
	    UINFO(8,"     rename to "<<nodep->name()<<endl);
	    // Move to module
	    nodep->unlinkFrBack();
	    m_modp->addStmtp(nodep);
	}
	nodep->iterateChildren(*this);
    }
    virtual void visit(AstVarXRef* nodep) {
	UINFO(9, "   VARXREF "<<nodep<<endl);
	if (m_namedScope != "" && nodep->inlinedDots() == "") {
	    nodep->inlinedDots(m_namedScope);
	    UINFO(9, "    rescope to "<<nodep<<endl);
	}
    }
    virtual void visit(AstScopeName* nodep) {
	// If there's a %m in the display text, we add a special node that will contain the name()
	// Similar code in V3Inline
	if (nodep->user1SetOnce()) return;  // Don't double-add text's
	if (m_namedScope != "") {
	    // To keep correct visual order, must add before other Text's
	    AstNode* afterp = nodep->scopeAttrp();
	    if (afterp) afterp->unlinkFrBackWithNext();
	    nodep->scopeAttrp(new AstText(nodep->fileline(), (string)"__DOT__"+m_namedScope));
	    if (afterp) nodep->scopeAttrp(afterp);
	}
	nodep->iterateChildren(*this);
    }
    virtual void visit(AstCoverDecl* nodep) {
	// Don't need to fix path in coverage statements, they're not under
	// any BEGINs, but V3Coverage adds them all under the module itself.
	nodep->iterateChildren(*this);
    }
    // VISITORS - LINT CHECK
    virtual void visit(AstIf* nodep) { // Note not AstNodeIf; other types don't get covered
	// Check IFDEPTH warning - could be in other transform files if desire
	int prevIfDepth = m_ifDepth;
	if (m_ifDepth == -1 || v3Global.opt.ifDepth()<1) { // Turned off
	} else if (nodep->uniquePragma() || nodep->unique0Pragma() || nodep->priorityPragma()) {
	    m_ifDepth = -1;
	} else if (++m_ifDepth > v3Global.opt.ifDepth()) {
	    nodep->v3warn(IFDEPTH,"Deep 'if' statement; suggest unique/priority to avoid slow logic");
	    nodep->fileline()->modifyWarnOff(V3ErrorCode::IFDEPTH, true);  // Warn only once
	    m_ifDepth = -1;
	}
	nodep->iterateChildren(*this);
	m_ifDepth = prevIfDepth;
    }
    virtual void visit(AstNode* nodep) {
	nodep->iterateChildren(*this);
    }
public:
    // CONSTUCTORS
    BeginVisitor(AstNetlist* nodep, BeginState* statep) {
	m_statep = statep;
	m_modp = NULL;
	m_ftaskp = NULL;
	m_repeatNum = 0;
	m_ifDepth = 0;
	nodep->accept(*this);
    }
    virtual ~BeginVisitor() {}
};

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

class BeginRelinkVisitor : public AstNVisitor {
    // Replace tasks with new pointer
private:
    // NODE STATE
    //  Input:
    //   AstNodeFTask::user1p		// Node replaced, rename it

    // VISITORS
    virtual void visit(AstNodeFTaskRef* nodep) {
	if (nodep->taskp()->user1()) { // It was converted
	    UINFO(9, "    relinkFTask "<<nodep<<endl);
	    nodep->name(nodep->taskp()->name());
	}
	nodep->iterateChildren(*this);
    }
    virtual void visit(AstVarRef* nodep) {
	if (nodep->varp()->user1()) { // It was converted
	    UINFO(9, "    relinVarRef "<<nodep<<endl);
	    nodep->name(nodep->varp()->name());
	}
	nodep->iterateChildren(*this);
    }
    virtual void visit(AstIfaceRefDType* nodep) {
	// May have changed cell names
	// TypeTable is always after all modules, so names are stable
	UINFO(8,"   IFACEREFDTYPE "<<nodep<<endl);
	if (nodep->cellp()) nodep->cellName(nodep->cellp()->name());
	UINFO(8,"       rename to "<<nodep<<endl);
	nodep->iterateChildren(*this);
    }
    //--------------------
    virtual void visit(AstNode* nodep) {
	nodep->iterateChildren(*this);
    }
public:
    // CONSTUCTORS
    BeginRelinkVisitor(AstNetlist* nodep, BeginState*) {
	nodep->accept(*this);
    }
    virtual ~BeginRelinkVisitor() {}
};

//######################################################################
// Task class functions

void V3Begin::debeginAll(AstNetlist* nodep) {
    UINFO(2,__FUNCTION__<<": "<<endl);
    BeginState state;
    { BeginVisitor bvisitor (nodep,&state); }
    if (state.anyFuncInBegin()) {
	BeginRelinkVisitor brvisitor (nodep,&state);
    }
    V3Global::dumpCheckGlobalTree("begin.tree", 0, v3Global.opt.dumpTreeLevel(__FILE__) >= 3);
}