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457 lines
17 KiB
C++
457 lines
17 KiB
C++
// -*- mode: C++; c-file-style: "cc-mode" -*-
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//*************************************************************************
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// DESCRIPTION: Verilator: Clocking POS/NEGEDGE insertion
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//
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// Code available from: http://www.veripool.org/verilator
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//
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//*************************************************************************
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//
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// Copyright 2003-2018 by Wilson Snyder. This program is free software; you can
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// redistribute it and/or modify it under the terms of either the GNU
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// Lesser General Public License Version 3 or the Perl Artistic License
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// Version 2.0.
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//
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// Verilator is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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//*************************************************************************
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// V3Clock's Transformations:
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//
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// Top Scope:
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// Check created ACTIVEs
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// Compress adjacent ACTIVEs with same sensitivity list
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// Form master _eval function
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// Add around the SENTREE a (IF POSEDGE(..))
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// Add a __Vlast_{clock} for the comparison
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// Set the __Vlast_{clock} at the end of the block
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// Replace UNTILSTABLEs with loops until specified signals become const.
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// Create global calling function for any per-scope functions. (For FINALs).
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//
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//*************************************************************************
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#include "config_build.h"
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#include "verilatedos.h"
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#include "V3Global.h"
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#include "V3Clock.h"
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#include "V3Ast.h"
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#include "V3EmitCBase.h"
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#include <algorithm>
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#include <cstdarg>
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//######################################################################
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// Clock state, as a visitor of each AstNode
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class ClockVisitor : public AstNVisitor {
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private:
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// NODE STATE
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// Cleared each Module:
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// AstVarScope::user1p() -> AstVarScope*. Temporary signal that was created.
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AstUser1InUse m_inuser1;
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// TYPES
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enum { DOUBLE_OR_RATE = 10 }; // How many | per ||, Determined experimentally as best
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// STATE
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AstNodeModule* m_modp; // Current module
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AstTopScope* m_topScopep; // Current top scope
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AstScope* m_scopep; // Current scope
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AstCFunc* m_evalFuncp; // Top eval function we are creating
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AstCFunc* m_initFuncp; // Top initial function we are creating
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AstCFunc* m_finalFuncp; // Top final function we are creating
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AstCFunc* m_settleFuncp; // Top settlement function we are creating
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AstSenTree* m_lastSenp; // Last sensitivity match, so we can detect duplicates.
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AstIf* m_lastIfp; // Last sensitivity if active to add more under
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AstMTaskBody* m_mtaskBodyp; // Current mtask body
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// METHODS
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VL_DEBUG_FUNC; // Declare debug()
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AstVarScope* getCreateLastClk(AstVarScope* vscp) {
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if (vscp->user1p()) return static_cast<AstVarScope*>(vscp->user1p());
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AstVar* varp = vscp->varp();
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if (!varp->width1()) varp->v3error("Unsupported: Clock edge on non-single bit signal: "<<varp->prettyName());
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string newvarname = (string("__Vclklast__")+vscp->scopep()->nameDotless()+"__"+varp->name());
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AstVar* newvarp = new AstVar(vscp->fileline(), AstVarType::MODULETEMP, newvarname, VFlagLogicPacked(), 1);
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newvarp->noReset(true); // Reset by below assign
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m_modp->addStmtp(newvarp);
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AstVarScope* newvscp = new AstVarScope(vscp->fileline(), m_scopep, newvarp);
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vscp->user1p(newvscp);
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m_scopep->addVarp(newvscp);
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// Add init
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AstNode* fromp = new AstVarRef(newvarp->fileline(), vscp, false);
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if (v3Global.opt.xInitialEdge()) fromp = new AstNot(fromp->fileline(), fromp);
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AstNode* newinitp = new AstAssign(vscp->fileline(),
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new AstVarRef(newvarp->fileline(), newvscp, true),
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fromp);
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addToInitial(newinitp);
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// At bottom, assign them
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AstAssign* finalp
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= new AstAssign(vscp->fileline(),
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new AstVarRef(vscp->fileline(), newvscp, true),
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new AstVarRef(vscp->fileline(), vscp, false));
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m_evalFuncp->addFinalsp(finalp);
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//
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UINFO(4,"New Last: "<<newvscp<<endl);
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return newvscp;
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}
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AstNode* createSenItemEquation(AstSenItem* nodep) {
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// We know the var is clean, and one bit, so we use binary ops
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// for speed instead of logical ops.
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// POSEDGE: var & ~var_last
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// NEGEDGE: ~var & var_last
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// BOTHEDGE: var ^ var_last
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// HIGHEDGE: var
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// LOWEDGE: ~var
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AstNode* newp = NULL;
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if (nodep->edgeType()==AstEdgeType::ET_ILLEGAL) {
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if (!v3Global.opt.bboxUnsup()) {
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nodep->v3error("Unsupported: Complicated event expression in sensitive activity list");
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}
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return NULL;
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}
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AstVarScope* clkvscp = nodep->varrefp()->varScopep();
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if (nodep->edgeType()==AstEdgeType::ET_POSEDGE) {
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AstVarScope* lastVscp = getCreateLastClk(clkvscp);
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newp = new AstAnd(nodep->fileline(),
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new AstVarRef(nodep->fileline(),
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nodep->varrefp()->varScopep(), false),
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new AstNot(nodep->fileline(),
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new AstVarRef(nodep->fileline(),
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lastVscp, false)));
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} else if (nodep->edgeType()==AstEdgeType::ET_NEGEDGE) {
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AstVarScope* lastVscp = getCreateLastClk(clkvscp);
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newp = new AstAnd(nodep->fileline(),
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new AstNot(nodep->fileline(),
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new AstVarRef(nodep->fileline(),
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nodep->varrefp()->varScopep(), false)),
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new AstVarRef(nodep->fileline(), lastVscp, false));
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} else if (nodep->edgeType()==AstEdgeType::ET_BOTHEDGE) {
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AstVarScope* lastVscp = getCreateLastClk(clkvscp);
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newp = new AstXor(nodep->fileline(),
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new AstVarRef(nodep->fileline(),
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nodep->varrefp()->varScopep(), false),
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new AstVarRef(nodep->fileline(), lastVscp, false));
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} else if (nodep->edgeType()==AstEdgeType::ET_HIGHEDGE) {
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newp = new AstVarRef(nodep->fileline(),
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clkvscp, false);
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} else if (nodep->edgeType()==AstEdgeType::ET_LOWEDGE) {
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newp = new AstNot(nodep->fileline(),
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new AstVarRef(nodep->fileline(),
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clkvscp, false));
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} else {
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nodep->v3fatalSrc("Bad edge type");
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}
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return newp;
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}
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AstNode* createSenGateEquation(AstSenGate* nodep) {
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AstNode* newp = new AstAnd(nodep->fileline(),
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createSenseEquation(nodep->sensesp()),
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nodep->rhsp()->cloneTree(true));
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return newp;
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}
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AstNode* createSenseEquation(AstNodeSenItem* nodesp) {
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// Nodep may be a list of elements; we need to walk it
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AstNode* senEqnp = NULL;
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for (AstNodeSenItem* senp = nodesp; senp; senp=VN_CAST(senp->nextp(), NodeSenItem)) {
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AstNode* senOnep = NULL;
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if (AstSenItem* itemp = VN_CAST(senp, SenItem)) {
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senOnep = createSenItemEquation(itemp);
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} else if (AstSenGate* itemp = VN_CAST(senp, SenGate)) {
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senOnep = createSenGateEquation(itemp);
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} else {
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senp->v3fatalSrc("Strange node under sentree");
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}
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if (senEqnp) {
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// Add new OR to the sensitivity list equation
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senEqnp = new AstOr(senp->fileline(), senEqnp, senOnep);
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} else {
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senEqnp = senOnep;
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}
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}
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return senEqnp;
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}
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AstIf* makeActiveIf(AstSenTree* sensesp) {
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AstNode* senEqnp = createSenseEquation(sensesp->sensesp());
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if (!senEqnp) sensesp->v3fatalSrc("No sense equation, shouldn't be in sequent activation.");
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AstIf* newifp = new AstIf(sensesp->fileline(), senEqnp, NULL, NULL);
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return (newifp);
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}
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void clearLastSen() {
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m_lastSenp = NULL;
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m_lastIfp = NULL;
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}
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// VISITORS
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virtual void visit(AstTopScope* nodep) {
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UINFO(4," TOPSCOPE "<<nodep<<endl);
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m_topScopep=nodep;
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m_scopep = nodep->scopep();
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if (!m_scopep) nodep->v3fatalSrc("No scope found on top level, perhaps you have no statements?");
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//VV***** We reset all user1p()
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AstNode::user1ClearTree();
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// Make top functions
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{
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AstCFunc* funcp = new AstCFunc(nodep->fileline(), "_eval", m_scopep);
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funcp->argTypes(EmitCBaseVisitor::symClassVar());
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funcp->dontCombine(true);
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funcp->symProlog(true);
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funcp->isStatic(true);
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funcp->entryPoint(true);
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m_scopep->addActivep(funcp);
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m_evalFuncp = funcp;
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}
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{
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AstCFunc* funcp = new AstCFunc(nodep->fileline(), "_eval_initial", m_scopep);
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funcp->argTypes(EmitCBaseVisitor::symClassVar());
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funcp->dontCombine(true);
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funcp->slow(true);
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funcp->symProlog(true);
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funcp->isStatic(true);
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funcp->entryPoint(true);
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m_scopep->addActivep(funcp);
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m_initFuncp = funcp;
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}
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{
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AstCFunc* funcp = new AstCFunc(nodep->fileline(), "final", m_scopep);
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funcp->skipDecl(true);
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funcp->dontCombine(true);
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funcp->slow(true);
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funcp->isStatic(false);
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funcp->entryPoint(true);
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funcp->addInitsp(new AstCStmt(nodep->fileline(),
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EmitCBaseVisitor::symClassVar()+" = this->__VlSymsp;\n"));
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funcp->addInitsp(new AstCStmt(nodep->fileline(), EmitCBaseVisitor::symTopAssign()+"\n"));
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m_scopep->addActivep(funcp);
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m_finalFuncp = funcp;
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}
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{
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AstCFunc* funcp = new AstCFunc(nodep->fileline(), "_eval_settle", m_scopep);
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funcp->argTypes(EmitCBaseVisitor::symClassVar());
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funcp->dontCombine(true);
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funcp->slow(true);
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funcp->isStatic(true);
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funcp->symProlog(true);
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funcp->entryPoint(true);
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m_scopep->addActivep(funcp);
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m_settleFuncp = funcp;
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}
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// Process the activates
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iterateChildren(nodep);
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// Done, clear so we can detect errors
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UINFO(4," TOPSCOPEDONE "<<nodep<<endl);
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clearLastSen();
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m_topScopep=NULL;
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m_scopep = NULL;
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}
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virtual void visit(AstNodeModule* nodep) {
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//UINFO(4," MOD "<<nodep<<endl);
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m_modp = nodep;
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iterateChildren(nodep);
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m_modp= NULL;
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}
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virtual void visit(AstScope* nodep) {
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//UINFO(4," SCOPE "<<nodep<<endl);
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m_scopep = nodep;
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iterateChildren(nodep);
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if (AstNode* movep = nodep->finalClksp()) {
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if (!m_topScopep) nodep->v3fatalSrc("Final clocks under non-top scope");
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movep->unlinkFrBackWithNext();
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m_evalFuncp->addFinalsp(movep);
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}
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m_scopep = NULL;
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}
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virtual void visit(AstAlways* nodep) {
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AstNode* cmtp = new AstComment(nodep->fileline(), nodep->typeName());
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nodep->replaceWith(cmtp);
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if (AstNode* stmtsp = nodep->bodysp()) {
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stmtsp->unlinkFrBackWithNext();
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cmtp->addNextHere(stmtsp);
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}
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nodep->deleteTree(); VL_DANGLING(nodep);
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}
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virtual void visit(AstAlwaysPost* nodep) {
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AstNode* cmtp = new AstComment(nodep->fileline(), nodep->typeName());
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nodep->replaceWith(cmtp);
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if (AstNode* stmtsp = nodep->bodysp()) {
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stmtsp->unlinkFrBackWithNext();
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cmtp->addNextHere(stmtsp);
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}
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nodep->deleteTree(); VL_DANGLING(nodep);
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}
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virtual void visit(AstCoverToggle* nodep) {
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//nodep->dumpTree(cout,"ct:");
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//COVERTOGGLE(INC, ORIG, CHANGE) ->
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// IF(ORIG ^ CHANGE) { INC; CHANGE = ORIG; }
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AstNode* incp = nodep->incp()->unlinkFrBack();
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AstNode* origp = nodep->origp()->unlinkFrBack();
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AstNode* changep = nodep->changep()->unlinkFrBack();
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AstIf* newp = new AstIf(nodep->fileline(),
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new AstXor(nodep->fileline(),
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origp,
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changep),
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incp, NULL);
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// We could add another IF to detect posedges, and only increment if so.
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// It's another whole branch though verus a potential memory miss.
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// We'll go with the miss.
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newp->addIfsp(new AstAssign(nodep->fileline(),
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changep->cloneTree(false),
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origp->cloneTree(false)));
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nodep->replaceWith(newp); nodep->deleteTree(); VL_DANGLING(nodep);
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}
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virtual void visit(AstInitial* nodep) {
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AstNode* cmtp = new AstComment(nodep->fileline(), nodep->typeName());
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nodep->replaceWith(cmtp);
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if (AstNode* stmtsp = nodep->bodysp()) {
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stmtsp->unlinkFrBackWithNext();
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cmtp->addNextHere(stmtsp);
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}
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nodep->deleteTree(); VL_DANGLING(nodep);
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}
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virtual void visit(AstCFunc* nodep) {
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iterateChildren(nodep);
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// Link to global function
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if (nodep->formCallTree()) {
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UINFO(4, " formCallTree "<<nodep<<endl);
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AstCCall* callp = new AstCCall(nodep->fileline(), nodep);
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callp->argTypes("vlSymsp");
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m_finalFuncp->addStmtsp(callp);
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}
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}
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virtual void visit(AstSenTree* nodep) {
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// Delete it later; Actives still pointing to it
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nodep->unlinkFrBack();
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pushDeletep(nodep);
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}
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void addToEvalLoop(AstNode* stmtsp) {
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m_evalFuncp->addStmtsp(stmtsp); // add to top level function
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}
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void addToSettleLoop(AstNode* stmtsp) {
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m_settleFuncp->addStmtsp(stmtsp); // add to top level function
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}
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void addToInitial(AstNode* stmtsp) {
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m_initFuncp->addStmtsp(stmtsp); // add to top level function
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}
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virtual void visit(AstActive* nodep) {
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// Careful if adding variables here, ACTIVES can be under other ACTIVES
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// Need to save and restore any member state in AstUntilStable block
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if (!m_topScopep || !nodep->stmtsp()) {
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// Not at the top or empty block...
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// Only empty blocks should be leftover on the non-top. Killem.
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if (nodep->stmtsp()) nodep->v3fatalSrc("Non-empty lower active");
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nodep->unlinkFrBack()->deleteTree(); VL_DANGLING(nodep);
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} else if (m_mtaskBodyp) {
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UINFO(4," TR ACTIVE "<<nodep<<endl);
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AstNode* stmtsp = nodep->stmtsp()->unlinkFrBackWithNext();
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if (nodep->hasClocked()) {
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if (nodep->hasInitial()) nodep->v3fatalSrc("Initial block should not have clock sensitivity");
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if (m_lastSenp && nodep->sensesp()->sameTree(m_lastSenp)) {
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UINFO(4," sameSenseTree\n");
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} else {
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clearLastSen();
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m_lastSenp = nodep->sensesp();
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// Make a new if statement
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m_lastIfp = makeActiveIf(m_lastSenp);
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m_mtaskBodyp->addStmtsp(m_lastIfp);
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}
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// Move statements to if
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m_lastIfp->addIfsp(stmtsp);
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} else if (nodep->hasInitial() || nodep->hasSettle()) {
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nodep->v3fatalSrc("MTask should not include initial/settle logic.");
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} else {
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// Combo logic. Move statements to mtask func.
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clearLastSen();
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m_mtaskBodyp->addStmtsp(stmtsp);
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}
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nodep->unlinkFrBack()->deleteTree(); VL_DANGLING(nodep);
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} else {
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UINFO(4," ACTIVE "<<nodep<<endl);
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AstNode* stmtsp = nodep->stmtsp()->unlinkFrBackWithNext();
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if (nodep->hasClocked()) {
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// Remember the latest sensitivity so we can compare it next time
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if (nodep->hasInitial()) nodep->v3fatalSrc("Initial block should not have clock sensitivity");
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if (m_lastSenp && nodep->sensesp()->sameTree(m_lastSenp)) {
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UINFO(4," sameSenseTree\n");
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} else {
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clearLastSen();
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m_lastSenp = nodep->sensesp();
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// Make a new if statement
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m_lastIfp = makeActiveIf(m_lastSenp);
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addToEvalLoop(m_lastIfp);
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}
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// Move statements to if
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m_lastIfp->addIfsp(stmtsp);
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} else if (nodep->hasInitial()) {
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// Don't need to: clearLastSen();, as we're adding it to different cfunc
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// Move statements to function
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addToInitial(stmtsp);
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} else if (nodep->hasSettle()) {
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// Don't need to: clearLastSen();, as we're adding it to different cfunc
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// Move statements to function
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addToSettleLoop(stmtsp);
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} else {
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// Combo
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clearLastSen();
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// Move statements to function
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addToEvalLoop(stmtsp);
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}
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nodep->unlinkFrBack()->deleteTree(); VL_DANGLING(nodep);
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}
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}
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virtual void visit(AstExecGraph* nodep) {
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for (m_mtaskBodyp = VN_CAST(nodep->op1p(), MTaskBody);
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m_mtaskBodyp;
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m_mtaskBodyp = VN_CAST(m_mtaskBodyp->nextp(), MTaskBody)) {
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clearLastSen();
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iterate(m_mtaskBodyp);
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}
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clearLastSen();
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// Move the ExecGraph into _eval. Its location marks the
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// spot where the graph will execute, relative to other
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// (serial) logic in the cycle.
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nodep->unlinkFrBack();
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addToEvalLoop(nodep);
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}
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//--------------------
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// Default: Just iterate
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virtual void visit(AstNode* nodep) {
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iterateChildren(nodep);
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}
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public:
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// CONSTUCTORS
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explicit ClockVisitor(AstNetlist* nodep) {
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m_modp = NULL;
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m_evalFuncp = NULL;
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m_initFuncp = NULL;
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m_finalFuncp = NULL;
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m_settleFuncp = NULL;
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m_topScopep = NULL;
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m_lastSenp = NULL;
|
||
m_lastIfp = NULL;
|
||
m_scopep = NULL;
|
||
m_mtaskBodyp = NULL;
|
||
//
|
||
iterate(nodep);
|
||
// Allow downstream modules to find _eval()
|
||
// easily without iterating through the tree.
|
||
nodep->evalp(m_evalFuncp);
|
||
}
|
||
virtual ~ClockVisitor() {}
|
||
};
|
||
|
||
//######################################################################
|
||
// Clock class functions
|
||
|
||
void V3Clock::clockAll(AstNetlist* nodep) {
|
||
UINFO(2,__FUNCTION__<<": "<<endl);
|
||
{
|
||
ClockVisitor visitor (nodep);
|
||
} // Destruct before checking
|
||
V3Global::dumpCheckGlobalTree("clock", 0, v3Global.opt.dumpTreeLevel(__FILE__) >= 3);
|
||
}
|