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269 lines
9.5 KiB
C++
269 lines
9.5 KiB
C++
//*************************************************************************
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// DESCRIPTION: Verilator: Replace return/continue with jumps
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//
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// Code available from: http://www.veripool.org/verilator
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//
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// AUTHORS: Wilson Snyder with Paul Wasson, Duane Gabli
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//
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//*************************************************************************
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//
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// Copyright 2003-2012 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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// V3LinkJump's Transformations:
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//
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// Each module:
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// Look for BEGINs
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// BEGIN(VAR...) -> VAR ... {renamed}
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// FOR -> WHILEs
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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 <cstdio>
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#include <cstdarg>
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#include <unistd.h>
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#include <algorithm>
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#include <vector>
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#include "V3Global.h"
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#include "V3LinkJump.h"
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#include "V3Ast.h"
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//######################################################################
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class LinkJumpVisitor : public AstNVisitor {
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private:
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// TYPES
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typedef vector<AstBegin*> BeginStack;
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// STATE
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AstNodeModule* m_modp; // Current module
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AstNodeFTask* m_ftaskp; // Current function/task
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AstWhile* m_loopp; // Current loop
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bool m_loopInc; // In loop increment
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int m_repeatNum; // Repeat counter
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BeginStack m_beginStack; // All begin blocks above current node
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// METHODS
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static int debug() {
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static int level = -1;
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if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
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return level;
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}
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AstJumpLabel* findAddLabel(AstNode* nodep, bool endOfIter) {
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// Put label under given node, and if WHILE optionally at end of iteration
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UINFO(4,"Create label for "<<nodep<<endl);
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if (nodep->castJumpLabel()) return nodep->castJumpLabel(); // Done
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AstNode* underp = NULL;
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bool under_and_next = true;
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if (nodep->castBegin()) underp = nodep->castBegin()->stmtsp();
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else if (nodep->castNodeFTask()) underp = nodep->castNodeFTask()->stmtsp();
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else if (nodep->castWhile()) {
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if (endOfIter) {
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// Note we jump to end of bodysp; a FOR loop has its increment under incsp() which we don't skip
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underp = nodep->castWhile()->bodysp();
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} else {
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underp = nodep; under_and_next=false; // IE we skip the entire while
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}
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}
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else {
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nodep->v3fatalSrc("Unknown jump point for break/disable/continue");
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return NULL;
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}
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// Skip over variables as we'll just move them in a momement
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// Also this would otherwise prevent us from using a label twice
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// see t_func_return test.
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while (underp && underp->castVar()) underp = underp->nextp();
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if (underp) UINFO(5," Underpoint is "<<underp<<endl);
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if (!underp) {
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nodep->v3fatalSrc("Break/disable/continue not under expected statement");
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return NULL;
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} else if (underp->castJumpLabel()) {
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return underp->castJumpLabel();
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} else { // Move underp stuff to be under a new label
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AstJumpLabel* labelp = new AstJumpLabel(nodep->fileline(), NULL);
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AstNRelinker repHandle;
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if (under_and_next) underp->unlinkFrBackWithNext(&repHandle);
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else underp->unlinkFrBack(&repHandle);
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repHandle.relink(labelp);
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labelp->addStmtsp(underp);
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// Keep any AstVars under the function not under the new JumpLabel
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for (AstNode* nextp, *varp=underp; varp; varp = nextp) {
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nextp = varp->nextp();
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if (varp->castVar()) {
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labelp->addPrev(varp->unlinkFrBack());
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}
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}
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return labelp;
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}
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}
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// VISITORS
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virtual void visit(AstNodeModule* nodep, AstNUser*) {
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m_modp = nodep;
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m_repeatNum = 0;
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nodep->iterateChildren(*this);
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m_modp = NULL;
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}
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virtual void visit(AstNodeFTask* nodep, AstNUser*) {
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m_ftaskp = nodep;
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nodep->iterateChildren(*this);
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m_ftaskp = NULL;
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}
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virtual void visit(AstBegin* nodep, AstNUser*) {
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UINFO(8," "<<nodep<<endl);
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m_beginStack.push_back(nodep);
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nodep->iterateChildren(*this);
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m_beginStack.pop_back();
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}
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virtual void visit(AstRepeat* nodep, AstNUser*) {
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// So later optimizations don't need to deal with them,
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// REPEAT(count,body) -> loop=count,WHILE(loop>0) { body, loop-- }
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// Note var can be signed or unsigned based on original number.
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AstNode* countp = nodep->countp()->unlinkFrBackWithNext();
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string name = string("__Vrepeat")+cvtToStr(m_repeatNum++);
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// Spec says value is integral, if negative is ignored
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AstVar* varp = new AstVar(nodep->fileline(), AstVarType::BLOCKTEMP, name,
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AstBitPacked(), 32);
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varp->numeric(AstNumeric::SIGNED);
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varp->dtypep()->numeric(AstNumeric::SIGNED);
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varp->usedLoopIdx(true);
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m_modp->addStmtp(varp);
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AstNode* initsp = new AstAssign(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, true),
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countp);
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AstNode* decp = new AstAssign(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, true),
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new AstSub(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, false),
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new AstConst(nodep->fileline(), 1)));
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V3Number zero (nodep->fileline(), 32, 0); zero.isSigned(true);
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AstNode* zerosp = new AstConst(nodep->fileline(), zero);
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AstNode* condp = new AstGtS(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, false),
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zerosp);
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AstNode* bodysp = nodep->bodysp(); if (bodysp) bodysp->unlinkFrBackWithNext();
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AstNode* newp = new AstWhile(nodep->fileline(),
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condp,
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bodysp,
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decp);
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initsp = initsp->addNext(newp);
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newp = initsp;
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nodep->replaceWith(newp);
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nodep->deleteTree(); nodep=NULL;
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}
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virtual void visit(AstWhile* nodep, AstNUser*) {
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// Don't need to track AstRepeat/AstFor as they have already been converted
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AstWhile* lastLoopp = m_loopp;
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bool lastInc = m_loopInc;
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m_loopp = nodep;
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m_loopInc = false;
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nodep->precondsp()->iterateAndNext(*this);
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nodep->condp()->iterateAndNext(*this);
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nodep->bodysp()->iterateAndNext(*this);
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m_loopInc = true;
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nodep->incsp()->iterateAndNext(*this);
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m_loopInc = lastInc;
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m_loopp = lastLoopp;
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}
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virtual void visit(AstReturn* nodep, AstNUser*) {
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nodep->iterateChildren(*this);
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AstFunc* funcp = m_ftaskp->castFunc();
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if (!m_ftaskp) { nodep->v3error("Return isn't underneath a task or function"); }
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else if (funcp && !nodep->lhsp()) { nodep->v3error("Return underneath a function should have return value"); }
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else if (!funcp && nodep->lhsp()) { nodep->v3error("Return underneath a task shouldn't have return value"); }
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else {
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if (funcp && nodep->lhsp()) {
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// Set output variable to return value
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nodep->addPrev(new AstAssign(nodep->fileline(),
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new AstVarRef(nodep->fileline(), funcp->fvarp()->castVar(), true),
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nodep->lhsp()->unlinkFrBackWithNext()));
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}
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// Jump to the end of the function call
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AstJumpLabel* labelp = findAddLabel(m_ftaskp, false);
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nodep->addPrev(new AstJumpGo(nodep->fileline(), labelp));
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}
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nodep->unlinkFrBack(); pushDeletep(nodep); nodep=NULL;
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}
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virtual void visit(AstBreak* nodep, AstNUser*) {
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nodep->iterateChildren(*this);
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if (!m_loopp) { nodep->v3error("break isn't underneath a loop"); }
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else {
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// Jump to the end of the loop
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AstJumpLabel* labelp = findAddLabel(m_loopp, false);
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nodep->addNextHere(new AstJumpGo(nodep->fileline(), labelp));
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}
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nodep->unlinkFrBack(); pushDeletep(nodep); nodep=NULL;
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}
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virtual void visit(AstContinue* nodep, AstNUser*) {
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nodep->iterateChildren(*this);
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if (!m_loopp) { nodep->v3error("continue isn't underneath a loop"); }
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else {
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// Jump to the end of this iteration
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// If a "for" loop then need to still do the post-loop increment
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AstJumpLabel* labelp = findAddLabel(m_loopp, true);
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nodep->addNextHere(new AstJumpGo(nodep->fileline(), labelp));
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}
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nodep->unlinkFrBack(); pushDeletep(nodep); nodep=NULL;
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}
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virtual void visit(AstDisable* nodep, AstNUser*) {
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UINFO(8," DISABLE "<<nodep<<endl);
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nodep->iterateChildren(*this);
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AstBegin* beginp = NULL;
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for (BeginStack::reverse_iterator it = m_beginStack.rbegin(); it != m_beginStack.rend(); ++it) {
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UINFO(9," UNDERBLK "<<*it<<endl);
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if ((*it)->name() == nodep->name()) {
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beginp = *it;
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break;
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}
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}
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//if (debug()>=9) { UINFO(0,"\n"); beginp->dumpTree(cout," labeli: "); }
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if (!beginp) { nodep->v3error("disable isn't underneath a begin with name: "<<nodep->name()); }
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else {
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// Jump to the end of the named begin
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AstJumpLabel* labelp = findAddLabel(beginp, false);
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nodep->addNextHere(new AstJumpGo(nodep->fileline(), labelp));
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}
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nodep->unlinkFrBack(); pushDeletep(nodep); nodep=NULL;
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//if (debug()>=9) { UINFO(0,"\n"); beginp->dumpTree(cout," labelo: "); }
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}
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virtual void visit(AstVarRef* nodep, AstNUser*) {
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if (m_loopInc && nodep->varp()) nodep->varp()->usedLoopIdx(true);
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}
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virtual void visit(AstConst* nodep, AstNUser*) {}
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virtual void visit(AstNode* nodep, AstNUser*) {
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nodep->iterateChildren(*this);
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}
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public:
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// CONSTUCTORS
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LinkJumpVisitor(AstNetlist* nodep) {
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m_modp = NULL;
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m_ftaskp = NULL;
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m_loopp = NULL;
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m_loopInc = false;
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m_repeatNum = 0;
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nodep->accept(*this);
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}
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virtual ~LinkJumpVisitor() {}
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};
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//######################################################################
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// Task class functions
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void V3LinkJump::linkJump(AstNetlist* nodep) {
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UINFO(2,__FUNCTION__<<": "<<endl);
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LinkJumpVisitor bvisitor (nodep);
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}
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