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https://github.com/verilator/verilator.git
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87e8736823
Adds dtype() to every node, keep global table of dtypes and remove duplicates. Final merge from dtype branch.
390 lines
16 KiB
C++
390 lines
16 KiB
C++
// -*- mode: C++; c-file-style: "cc-mode" -*-
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//*************************************************************************
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// DESCRIPTION: Verilator: Expression width calculations
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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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// V3WidthSel's Transformations:
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// Top down traversal:
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// Replace SELPLUS/SELMINUS with SEL
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// Replace SELEXTRACT with SEL
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// Replace SELBIT with SEL or ARRAYSEL
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//
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// This code was once in V3LinkResolve, but little endian bit vectors won't
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// work that early. It was considered for V3Width and V3Param, but is
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// fairly ugly both places as the nodes change in too strongly
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// interconnected ways.
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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 "V3Global.h"
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#include "V3Width.h"
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#include "V3Const.h"
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//######################################################################
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// Width state, as a visitor of each AstNode
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class WidthSelVisitor : public AstNVisitor {
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private:
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// IMPORTANT
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//**** This is not a normal visitor, in that all iteration is instead
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// done by the caller (V3Width). This avoids duplicating much of the
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// complicated GenCase/GenFor/Cell/Function call logic that all depends
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// on if widthing top-down or just for parameters.
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#define iterateChildren DO_NOT_iterateChildern_IN_V3WidthSel
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//
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// NODE STATE
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// isBelowSeled() used insead of userp, as we're out of
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// non-conflicting users, and having a persistent variable means this
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// code can be skipped during most later stage constification calls.
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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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void checkConstantOrReplace(AstNode* nodep, const string& message) {
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// Note can't call V3Const::constifyParam(nodep) here, as constify may change nodep on us!
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if (!nodep->castConst()) {
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nodep->v3error(message);
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nodep->replaceWith(new AstConst(nodep->fileline(), AstConst::Unsized32(), 1));
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pushDeletep(nodep); nodep=NULL;
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}
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}
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AstNodeDType* dtypeForExtractp(AstNode* nodep, AstNode* basefromp, int dimension, bool rangedSelect) {
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// Perform error checks on the node
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AstVar* varp = varFromBasefrom(basefromp);
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//UINFO(9,"SCD\n"); if (debug()>=9) varp->dumpTree(cout,"-dtfexvar: ");
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// This may be called on dotted variables before we've completed widthing of the dotted var.
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AstNodeDType* ddtypep = varp->dtypep() ? varp->dtypep() : varp->childDTypep();
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if (!ddtypep) nodep->v3fatalSrc("No datatype found for variable in select");
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ddtypep = ddtypep->dtypeDimensionp(dimension);
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if (debug()>=9 &&ddtypep) ddtypep->dumpTree(cout,"-ddtypep: ");
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if (AstArrayDType* adtypep = ddtypep->castArrayDType()) {
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return adtypep;
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}
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else if (AstBasicDType* adtypep = ddtypep->castBasicDType()) {
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if (!adtypep->isRanged()) {
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nodep->v3error("Illegal bit select; variable does not have a bit range, or bad dimension: "<<varp->prettyName());
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return NULL;
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}
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return adtypep;
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}
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else {
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nodep->v3error("Illegal bit or array select; variable already selected, or bad dimension: "<<varp->prettyName());
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}
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return NULL;
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}
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AstNode* newSubNeg(AstNode* lhsp, vlsint32_t rhs) {
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// Return lhs-rhs, but if rhs is negative use an add, so we won't
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// have to deal with signed math and related 32bit sign extension problems
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if (rhs == 0) {
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return lhsp;
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} else if (lhsp->castConst()) {
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// Optional vs just making add/sub below, but saves constification some work
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V3Number num (lhsp->fileline(), lhsp->width());
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num.opSub(lhsp->castConst()->num(), V3Number(lhsp->fileline(), 32, rhs));
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num.isSigned(lhsp->isSigned());
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AstNode* newp = new AstConst(lhsp->fileline(), num);
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return newp;
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} else if (rhs > 0) {
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AstNode* newp = new AstSub(lhsp->fileline(), lhsp,
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new AstConst(lhsp->fileline(), AstConst::Unsized32(), rhs));
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// We must make sure sub gets sign of original value, not from the constant
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newp->dtypeFrom(lhsp);
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return newp;
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} else { // rhs < 0;
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AstNode* newp = new AstAdd(lhsp->fileline(), lhsp,
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new AstConst(lhsp->fileline(), AstConst::Unsized32(), -rhs));
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// We must make sure sub gets sign of original value, not from the constant
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newp->dtypeFrom(lhsp);
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return newp;
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}
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}
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AstNode* newSubNeg(vlsint32_t lhs, AstNode* rhsp) {
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// Return lhs-rhs
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// We must make sure sub gets sign of original value
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AstNode* newp = new AstSub(rhsp->fileline(),
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new AstConst(rhsp->fileline(), AstConst::Unsized32(), lhs),
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rhsp);
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newp->dtypeFrom(rhsp); // Important as AstSub default is lhs's sign
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return newp;
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}
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AstVar* varFromBasefrom(AstNode* basefromp) {
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AstNodeVarRef* varrefp = basefromp->castNodeVarRef();
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if (!varrefp) basefromp->v3fatalSrc("Bit/array selection of non-variable");
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AstVar* varp = varrefp->varp(); if (!varp) varrefp->v3fatalSrc("Signal not linked");
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return varp;
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}
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AstNode* newSubLsbOf(AstNode* underp, AstNode* basefromp) {
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// Account for a variable's LSB in bit selections
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// Will likely become SUB(underp, lsb_of_signal)
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// Don't report WIDTH warnings etc here, as may be inside a generate branch that will be deleted
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AstVar* varp = varFromBasefrom(basefromp);
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// SUB #'s Not needed when LSB==0 and MSB>=0 (ie [0:-13] must still get added!)
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if (!varp->basicp()->isRanged()) {
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// vector without range, or 0 lsb is ok, for example a INTEGER x; y = x[21:0];
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return underp;
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} else {
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if (varp->basicp()->rangep()
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&& (!varp->basicp()->rangep()->msbp()->castConst()
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|| !varp->basicp()->rangep()->lsbp()->castConst()))
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varp->v3fatalSrc("Non-constant variable range; errored earlier"); // in constifyParam(varp)
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if (varp->basicp()->littleEndian()) {
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// reg [1:3] was swapped to [3:1] (lsbEndianedp==3) and needs a SUB(3,under)
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AstNode* newp = newSubNeg(varp->basicp()->msb(), underp);
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return newp;
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} else {
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// reg [3:1] needs a SUB(under,1)
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AstNode* newp = newSubNeg(underp, varp->basicp()->lsb());
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return newp;
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}
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}
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}
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// VISITORS
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// If adding new visitors, insure V3Width's visit(TYPE) calls into here
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virtual void visit(AstRange* nodep, AstNUser*) {
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// Convert all range values to constants
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UINFO(6,"RANGE "<<nodep<<endl);
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V3Const::constifyParamsEdit(nodep->msbp()); // May relink pointed to node
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V3Const::constifyParamsEdit(nodep->lsbp()); // May relink pointed to node
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checkConstantOrReplace(nodep->msbp(), "MSB of bit range isn't a constant");
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checkConstantOrReplace(nodep->lsbp(), "LSB of bit range isn't a constant");
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int msb = nodep->msbConst();
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int lsb = nodep->lsbConst();
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if (msb<lsb) {
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// If it's an array, ok to have either ordering, we'll just correct
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// So, see if we're sitting under a variable's arrayp.
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AstNode* huntbackp = nodep;
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while (huntbackp->backp()->castRange()) huntbackp=huntbackp->backp();
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if (huntbackp->backp()->castArrayDType()) {
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} else {
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// Little endian bits are legal, just remember to swap
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// Warning is in V3Width to avoid false warnings when in "off" generate if's
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nodep->littleEndian(!nodep->littleEndian());
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}
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// Internally we'll always have msb() be the greater number
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// We only need to correct when doing [] AstSel extraction,
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// and when tracing the vector.
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nodep->msbp()->swapWith(nodep->lsbp());
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}
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}
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virtual void visit(AstSelBit* nodep, AstNUser*) {
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UINFO(6,"SELBIT "<<nodep<<endl);
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if (debug()>=9) nodep->backp()->dumpTree(cout,"-vsbin(-1): ");
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// lhsp/rhsp do not need to be constant
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AstNode* basefromp = AstArraySel::baseFromp(nodep->attrp());
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int dimension = AstArraySel::dimension(nodep->fromp()); // Not attrp as need hierarchy
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AstNodeDType* ddtypep = dtypeForExtractp(nodep, basefromp, dimension, false);
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AstNode* fromp = nodep->lhsp()->unlinkFrBack();
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AstNode* bitp = nodep->rhsp()->unlinkFrBack();
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if (debug()>=9) ddtypep->dumpTree(cout,"-ddtypep: ");
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if (debug()>=9) nodep->dumpTree(cout,"-vsbmd: ");
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if (AstArrayDType* adtypep = ddtypep->castArrayDType()) {
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// SELBIT(array, index) -> ARRAYSEL(array, index)
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AstNode* subp = bitp;
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if (adtypep->lsb()!=0 || adtypep->msb()<0) {
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subp = newSubNeg (subp, adtypep->lsb());
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}
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AstArraySel* newp = new AstArraySel (nodep->fileline(),
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fromp, subp);
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UINFO(6," newd"<<dimension<<" "<<newp<<endl);
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nodep->replaceWith(newp); pushDeletep(nodep); nodep=NULL;
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}
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else if (AstBasicDType* adtypep = ddtypep->castBasicDType()) {
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if (adtypep) {} // unused
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// SELBIT(range, index) -> SEL(array, index, 1)
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AstSel* newp = new AstSel (nodep->fileline(),
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fromp,
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newSubLsbOf(bitp, basefromp),
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// Unsized so width from user
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new AstConst (nodep->fileline(),AstConst::Unsized32(),1));
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UINFO(6," new "<<newp<<endl); if (debug()>=9) newp->dumpTree(cout,"-vsbnw: ");
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nodep->replaceWith(newp); pushDeletep(nodep); nodep=NULL;
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}
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else { // NULL=bad extract, or unknown node type
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nodep->v3error("Illegal bit or array select; variable already selected, or bad dimension");
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// How to recover? We'll strip a dimension.
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nodep->replaceWith(fromp); pushDeletep(nodep); nodep=NULL;
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}
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}
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virtual void visit(AstSelExtract* nodep, AstNUser*) {
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// SELEXTRACT(from,msb,lsb) -> SEL(from, lsb, 1+msb-lsb)
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UINFO(6,"SELEXTRACT "<<nodep<<endl);
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//if (debug()>=9) nodep->dumpTree(cout,"--SLEX0: ");
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// Below 2 lines may change nodep->widthp()
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V3Const::constifyParamsEdit(nodep->lsbp()); // May relink pointed to node
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V3Const::constifyParamsEdit(nodep->msbp()); // May relink pointed to node
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//if (debug()>=9) nodep->dumpTree(cout,"--SLEX3: ");
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checkConstantOrReplace(nodep->lsbp(), "First value of [a:b] isn't a constant, maybe you want +: or -:");
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checkConstantOrReplace(nodep->msbp(), "Second value of [a:b] isn't a constant, maybe you want +: or -:");
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AstNode* basefromp = AstArraySel::baseFromp(nodep->attrp());
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int dimension = AstArraySel::dimension(nodep->fromp()); // Not attrp as need hierarchy
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AstNode* fromp = nodep->lhsp()->unlinkFrBack();
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AstNode* msbp = nodep->rhsp()->unlinkFrBack();
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AstNode* lsbp = nodep->thsp()->unlinkFrBack();
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AstVar* varp = varFromBasefrom(basefromp);
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vlsint32_t msb = msbp->castConst()->toSInt();
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vlsint32_t lsb = lsbp->castConst()->toSInt();
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AstNodeDType* ddtypep = dtypeForExtractp(nodep, basefromp, dimension, msb!=lsb);
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if (AstArrayDType* adtypep = ddtypep->castArrayDType()) {
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if (adtypep) {}
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if (msb!=lsb) {
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AstArraySel* newp = new AstArraySel (nodep->fileline(), fromp, lsbp);
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newp->start(lsb);
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newp->length((msb - lsb) + 1);
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nodep->replaceWith(newp); pushDeletep(nodep); nodep=NULL;
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} else {
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nodep->v3error("Illegal bit select; can't bit extract from arrayed dimension: "<<varp->prettyName());
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}
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} else if (AstBasicDType* adtypep = ddtypep->castBasicDType()) {
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if (adtypep) {} // Unused
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if (varp->basicp()->littleEndian()) {
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// Below code assumes big bit endian; just works out if we swap
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int x = msb; msb = lsb; lsb = x;
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}
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if (lsb > msb) {
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nodep->v3error("["<<msb<<":"<<lsb<<"] Range extract has backward bit ordering, perhaps you wanted ["<<lsb<<":"<<msb<<"]");
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int x = msb; msb = lsb; lsb = x;
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}
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AstNode* widthp = new AstConst (msbp->fileline(), AstConst::Unsized32(), // Unsized so width from user
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msb +1-lsb);
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AstSel* newp = new AstSel (nodep->fileline(),
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fromp,
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newSubLsbOf(lsbp, basefromp),
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widthp);
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UINFO(6," new "<<newp<<endl);
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//if (debug()>=9) newp->dumpTree(cout,"--SLEXnew: ");
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nodep->replaceWith(newp); pushDeletep(nodep); nodep=NULL;
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pushDeletep(msbp); msbp=NULL;
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}
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else { // NULL=bad extract, or unknown node type
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nodep->v3error("Illegal range select; variable already selected, or bad dimension");
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// How to recover? We'll strip a dimension.
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nodep->replaceWith(fromp); pushDeletep(nodep); nodep=NULL;
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}
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}
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void replaceSelPlusMinus(AstNodePreSel* nodep) {
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UINFO(6,"SELPLUS/MINUS "<<nodep<<endl);
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// Below 2 lines may change nodep->widthp()
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V3Const::constifyParamsEdit(nodep->thsp()); // May relink pointed to node
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checkConstantOrReplace(nodep->thsp(), "Width of :+ or :- bit extract isn't a constant");
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// Now replace it with a AstSel
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AstNode* basefromp = AstArraySel::baseFromp(nodep->attrp());
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int dimension = AstArraySel::dimension(nodep->fromp()); // Not attrp as need hierarchy
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AstNode* fromp = nodep->lhsp()->unlinkFrBack();
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AstNode* rhsp = nodep->rhsp()->unlinkFrBack();
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AstNode* widthp = nodep->thsp()->unlinkFrBack();
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int width = widthp->castConst()->toSInt();
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//AstVar* varp = varFromBasefrom(basefromp);
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if (width > (1<<28)) nodep->v3error("Width of :+ or :- is huge; vector of over 1billion bits: "<<widthp->prettyName());
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if (width<0) nodep->v3error("Width of :+ or :- is < 0: "<<widthp->prettyName());
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AstNodeDType* ddtypep = dtypeForExtractp(nodep, basefromp, dimension, width!=1);
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if (AstBasicDType* adtypep = ddtypep->castBasicDType()) {
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AstSel* newp = NULL;
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if (nodep->castSelPlus()) {
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if (adtypep->littleEndian()) {
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// SELPLUS(from,lsb,width) -> SEL(from, (vector_msb-width+1)-sel, width)
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newp = new AstSel (nodep->fileline(),
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fromp,
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newSubNeg((adtypep->msb()-width+1), rhsp),
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widthp);
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} else {
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// SELPLUS(from,lsb,width) -> SEL(from, lsb-vector_lsb, width)
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newp = new AstSel (nodep->fileline(),
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fromp,
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newSubLsbOf(rhsp, basefromp),
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widthp);
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}
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} else if (nodep->castSelMinus()) {
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if (adtypep->littleEndian()) {
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// SELMINUS(from,msb,width) -> SEL(from, msb-[bit])
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newp = new AstSel (nodep->fileline(),
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fromp,
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newSubNeg(adtypep->msb(), rhsp),
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widthp);
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} else {
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// SELMINUS(from,msb,width) -> SEL(from, msb-(width-1)-lsb#)
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newp = new AstSel (nodep->fileline(),
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fromp,
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newSubNeg(rhsp, adtypep->lsb()+(width-1)),
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widthp);
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}
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} else {
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nodep->v3fatalSrc("Bad Case");
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}
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UINFO(6," new "<<newp<<endl);
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nodep->replaceWith(newp); pushDeletep(nodep); nodep=NULL;
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}
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else { // NULL=bad extract, or unknown node type
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nodep->v3error("Illegal +: or -: select; variable already selected, or bad dimension");
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// How to recover? We'll strip a dimension.
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nodep->replaceWith(fromp); pushDeletep(nodep); nodep=NULL;
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}
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}
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virtual void visit(AstSelPlus* nodep, AstNUser*) {
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replaceSelPlusMinus(nodep);
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}
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virtual void visit(AstSelMinus* nodep, AstNUser*) {
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replaceSelPlusMinus(nodep);
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}
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// If adding new visitors, insure V3Width's visit(TYPE) calls into here
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//--------------------
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// Default
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virtual void visit(AstNode* nodep, AstNUser*) {
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// See notes above; we never iterate
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}
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public:
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// CONSTUCTORS
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WidthSelVisitor() {}
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AstNode* mainAcceptEdit(AstNode* nodep) {
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return nodep->acceptSubtreeReturnEdits(*this);
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}
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virtual ~WidthSelVisitor() {}
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};
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//######################################################################
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// Width class functions
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AstNode* V3Width::widthSelNoIterEdit(AstNode* nodep) {
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WidthSelVisitor visitor;
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nodep = visitor.mainAcceptEdit(nodep);
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return nodep;
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}
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#undef iterateChildren
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