verilator/src/V3Slice.cpp
2014-01-06 19:28:57 -05:00

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// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Parse module/signal name references
//
// Code available from: http://www.veripool.org/verilator
//
//*************************************************************************
//
// Copyright 2003-2014 by Wilson Snyder. This program is free software; you can
// redistribute it and/or modify it under the terms of either the GNU
// Lesser General Public License Version 3 or the Perl Artistic License
// Version 2.0.
//
// Verilator is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
//*************************************************************************
// Slice TRANSFORMATIONS:
// Top-down traversal (SliceVisitor):
// NODEASSIGN
// ARRAYSEL
// Compare the dimensions to the Var to check for implicit slices.
// Using ->length() calculate the number of clones needed.
// VARREF
// Check the dimensions of the Var for an implicit slice.
// Replace with ArraySel nodes if needed.
// SEL, EXTEND
// We might be assigning a 1-D packed array to a 2-D packed array,
// this is unsupported.
// SliceCloneVisitor (called if this node is a slice):
// NODEASSIGN
// Clone and iterate the clone:
// ARRAYSEL
// Modify bitp() for the new value and set ->length(1)
//*************************************************************************
#include "config_build.h"
#include "verilatedos.h"
#include <cstdio>
#include <cstdarg>
#include <unistd.h>
#include "V3Global.h"
#include "V3Slice.h"
#include "V3Ast.h"
#include <vector>
class SliceCloneVisitor : public AstNVisitor {
// NODE STATE
// Inputs:
// AstArraySel::user1p() -> AstVarRef. The VarRef that the final ArraySel points to
// AstNodeAssign::user2() -> int. The number of clones needed for this assign
// AstArraySel::user3() -> bool. Error detected
// STATE
vector<vector<unsigned> > m_selBits; // Indexes of the ArraySel we are expanding
int m_vecIdx; // Current vector index
unsigned m_depth; // Number of ArraySel's from the VarRef
AstVarRef* m_refp; // VarRef under this ArraySel
// METHODS
static int debug() {
static int level = -1;
if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
return level;
}
// VISITORS
virtual void visit(AstArraySel* nodep, AstNUser*) {
if (!nodep->backp()->castArraySel()) {
// This is the top of an ArraySel, setup
m_refp = nodep->user1p()->castNode()->castVarRef();
m_vecIdx += 1;
if (m_vecIdx == (int)m_selBits.size()) {
m_selBits.push_back(vector<unsigned>());
AstVar* varp = m_refp->varp();
pair<uint32_t,uint32_t> arrDim = varp->dtypep()->dimensions(false);
uint32_t dimensions = arrDim.second;
for (uint32_t i = 0; i < dimensions; ++i) {
m_selBits[m_vecIdx].push_back(0);
}
}
}
nodep->iterateChildren(*this);
if (nodep->fromp()->castVarRef()) {
m_depth = 0;
} else {
++m_depth;
}
// Check if m_selBits has overflowed
if (m_selBits[m_vecIdx][m_depth] >= nodep->length()) {
m_selBits[m_vecIdx][m_depth] = 0;
if (m_depth + 1 < m_selBits[m_vecIdx].size())
m_selBits[m_vecIdx][m_depth+1] += 1;
}
// Reassign the bitp()
if (nodep->length() > 1) {
if (AstConst* bitp = nodep->bitp()->castConst()) {
unsigned idx = nodep->start() + m_selBits[m_vecIdx][m_depth];
AstNode* constp = new AstConst(bitp->fileline(), V3Number(bitp->fileline(), bitp->castConst()->num().width(), idx));
bitp->replaceWith(constp);
} else {
nodep->v3error("Unsupported: Only constants supported in slices");
}
}
if (!nodep->backp()->castArraySel()) {
// Top ArraySel, increment m_selBits
m_selBits[m_vecIdx][0] += 1;
}
nodep->length(1);
}
virtual void visit(AstNodeAssign* nodep, AstNUser*) {
if (nodep->user2() < 2) return; // Don't need clones
m_selBits.clear();
UINFO(4, "Cloning "<<nodep->user2()<<" times: "<<nodep<<endl);
for (int i = 0; i < nodep->user2(); ++i) {
// Clone the node and iterate over the clone
m_vecIdx = -1;
AstNodeAssign* clonep = nodep->cloneTree(false)->castNodeAssign();
clonep->iterateChildren(*this);
nodep->addNextHere(clonep);
}
nodep->unlinkFrBack()->deleteTree(); nodep = NULL;
}
// Not all Uniop nodes should be cloned down to a single bit
void cloneUniop(AstNodeUniop* nodep) {
if (nodep->user2() < 2) return; // Don't need clones
m_selBits.clear();
UINFO(4, "Cloning "<<nodep->user2()<<" times: "<<nodep<<endl);
AstNode* lhsp = NULL;
AstNode* rhsp = NULL;
for (int i = 0; i < nodep->user2(); ++i) {
// Clone the node and iterate over the clone
m_vecIdx = -1;
AstNodeUniop* clonep = nodep->cloneTree(false)->castNodeUniop();
clonep->iterateChildren(*this);
if (!lhsp) lhsp = clonep;
else rhsp = clonep;
if (lhsp && rhsp) {
switch (nodep->type()) {
case AstType::atREDOR:
lhsp = new AstOr(nodep->fileline(), lhsp, rhsp);
break;
case AstType::atREDAND:
lhsp = new AstAnd(nodep->fileline(), lhsp, rhsp);
break;
case AstType::atREDXOR:
lhsp = new AstXor(nodep->fileline(), lhsp, rhsp);
break;
case AstType::atREDXNOR:
lhsp = new AstXnor(nodep->fileline(), lhsp, rhsp);
break;
default:
nodep->v3fatalSrc("Unsupported: Unary operation on multiple packed dimensions");
break;
}
rhsp = NULL;
}
}
nodep->addNextHere(lhsp);
nodep->unlinkFrBack()->deleteTree(); nodep = NULL;
}
virtual void visit(AstRedOr* nodep, AstNUser*) {
cloneUniop(nodep);
}
virtual void visit(AstRedAnd* nodep, AstNUser*) {
cloneUniop(nodep);
}
virtual void visit(AstRedXor* nodep, AstNUser*) {
cloneUniop(nodep);
}
virtual void visit(AstRedXnor* nodep, AstNUser*) {
cloneUniop(nodep);
}
virtual void visit(AstNode* nodep, AstNUser*) {
// Default: Just iterate
nodep->iterateChildren(*this);
}
public:
// CONSTUCTORS
SliceCloneVisitor(AstNode* assignp) {
assignp->accept(*this);
}
virtual ~SliceCloneVisitor() {}
};
//*************************************************************************
class SliceVisitor : public AstNVisitor {
// NODE STATE
// Cleared on netlist
// AstNodeAssign::user1() -> bool. True if find is complete
// AstUniop::user1() -> bool. True if find is complete
// AstArraySel::user1p() -> AstVarRef. The VarRef that the final ArraySel points to
// AstNode::user2() -> int. The number of clones needed for this node
AstUser1InUse m_inuser1;
AstUser2InUse m_inuser2;
AstUser3InUse m_inuser3;
// TYPEDEFS
typedef pair<uint32_t, uint32_t> ArrayDimensions; // Array Dimensions (packed, unpacked)
// STATE
AstNode* m_assignp; // Assignment we are under
AstNodeVarRef* m_lhsVarRefp; // Var on the LHS
bool m_extend; // We have found an extend node
bool m_assignError; // True if the current assign already has an error
// METHODS
static int debug() {
static int level = -1;
if (VL_UNLIKELY(level < 0)) level = v3Global.opt.debugSrcLevel(__FILE__);
return level;
}
// Find out how many explicit dimensions are in a given ArraySel.
unsigned explicitDimensions(AstArraySel* nodep) {
unsigned dim = 0;
AstNode* fromp = nodep;
AstArraySel* selp;
do {
selp = fromp->castArraySel();
if (!selp) {
nodep->user1p(fromp->castVarRef());
selp = NULL;
break;
} else {
fromp = selp->fromp();
if (fromp) ++dim;
}
} while (fromp && selp);
if (!nodep->user1p()) nodep->v3fatalSrc("Couldn't find VarRef under the ArraySel");
return dim;
}
AstArraySel* insertImplicit(AstNode* nodep, unsigned start, unsigned count) {
// Insert any implicit slices as explicit slices (ArraySel nodes).
// Return a new pointer to replace nodep() in the ArraySel.
UINFO(9," insertImplicit "<<nodep<<endl);
AstVarRef* refp = nodep->user1p()->castNode()->castVarRef();
if (!refp) nodep->v3fatalSrc("No VarRef in user1 of node "<<nodep);
AstVar* varp = refp->varp();
AstNode* topp = nodep;
for (unsigned i = start; i < start + count; ++i) {
AstNodeDType* dtypep = varp->dtypep()->dtypeDimensionp(i-1);
AstUnpackArrayDType* adtypep = dtypep->castUnpackArrayDType();
if (!adtypep) nodep->v3fatalSrc("insertImplicit tried to expand an array without an ArrayDType");
vlsint32_t msb = adtypep->msb();
vlsint32_t lsb = adtypep->lsb();
if (lsb > msb) {
// Below code assumes big bit endian; just works out if we swap
int x = msb; msb = lsb; lsb = x;
}
UINFO(9," ArraySel-child: "<<topp<<endl);
AstArraySel* newp = new AstArraySel(nodep->fileline(), topp, new AstConst(nodep->fileline(),lsb));
if (!newp->dtypep()) {
newp->v3fatalSrc("ArraySel dtyping failed when resolving slice"); // see ArraySel constructor
}
newp->user1p(refp);
newp->start(lsb);
newp->length(msb - lsb + 1);
topp = newp->castNode();
}
return topp->castArraySel();
}
int countClones(AstArraySel* nodep) {
// Count how many clones we need to make from this ArraySel
int clones = 1;
AstNode* fromp = nodep;
AstArraySel* selp;
do {
selp = fromp->castArraySel();
fromp = (selp) ? selp->fromp() : NULL;
if (fromp && selp) clones *= selp->length();
} while (fromp && selp);
return clones;
}
// VISITORS
virtual void visit(AstVarRef* nodep, AstNUser*) {
// The LHS/RHS of an Assign may be to a Var that is an array. In this
// case we need to create a slice accross the entire Var
if (m_assignp && !nodep->backp()->castArraySel()) {
pair<uint32_t,uint32_t> arrDim = nodep->varp()->dtypep()->dimensions(false);
uint32_t dimensions = arrDim.second; // unpacked only
if (dimensions > 0) {
AstVarRef* clonep = nodep->cloneTree(false);
clonep->user1p(nodep);
AstNode* newp = insertImplicit(clonep, 1, dimensions);
nodep->replaceWith(newp); nodep = NULL;
newp->accept(*this);
}
}
}
virtual void visit(AstExtend* nodep, AstNUser*) {
m_extend = true;
if (m_assignp && m_assignp->user2() > 1 && !m_assignError) {
m_assignp->v3error("Unsupported: Assignment between unpacked arrays of different dimensions");
m_assignError = true;
}
nodep->iterateChildren(*this);
}
virtual void visit(AstConst* nodep, AstNUser*) {
m_extend = true;
if (m_assignp && m_assignp->user2() > 1 && !m_assignError) {
m_assignp->v3error("Unsupported: Assignment between a constant and an array slice");
m_assignError = true;
}
}
virtual void visit(AstArraySel* nodep, AstNUser*) {
if (!m_assignp) return;
if (nodep->user3()) return; // Prevent recursion on just created nodes
unsigned dim = explicitDimensions(nodep);
AstVarRef* refp = nodep->user1p()->castNode()->castVarRef();
pair<uint32_t,uint32_t> arrDim = refp->varp()->dtypep()->dimensions(false);
uint32_t implicit = (arrDim.second) - dim;
if (implicit > 0) {
AstArraySel* newp = insertImplicit(nodep->cloneTree(false), dim+1, implicit);
nodep->replaceWith(newp); nodep = newp;
nodep->user3(true);
}
int clones = countClones(nodep);
if (m_assignp->user2() > 0 && m_assignp->user2() != clones) {
m_assignp->v3error("Slices of arrays in assignments must have the same unpacked dimensions");
} else if (!m_assignp->user2()) {
if (m_extend && clones > 1 && !m_assignError) {
m_assignp->v3error("Unsupported: Assignment between unpacked arrays of different dimensions");
m_assignError = true;
}
if (clones > 1 && !refp->lvalue() && refp->varp() == m_lhsVarRefp->varp()
&& !m_assignp->castAssignDly() && !m_assignError) {
// LHS Var != RHS Var for a non-delayed assignment
m_assignp->v3error("Unsupported: Slices in a non-delayed assignment with the same Var on both sides");
m_assignError = true;
}
m_assignp->user2(clones);
}
}
virtual void visit(AstSel* nodep, AstNUser*) {
m_extend = true;
if (m_assignp && m_assignp->user2() > 1 && !m_assignError) {
m_assignp->v3error("Unsupported: Assignment between unpacked arrays of different dimensions");
m_assignError = true;
}
nodep->iterateChildren(*this);
}
virtual void visit(AstNodeCond* nodep, AstNUser*) {
// The conditional must be a single bit so only look at the expressions
nodep->expr1p()->accept(*this);
nodep->expr2p()->accept(*this);
}
// Return the first AstVarRef under the node
AstVarRef* findVarRefRecurse(AstNode* nodep) {
AstVarRef* refp = nodep->castVarRef();
if (refp) return refp;
if (nodep->op1p()) {
refp = findVarRefRecurse(nodep->op1p());
if (refp) return refp;
}
if (nodep->op2p()) {
refp = findVarRefRecurse(nodep->op2p());
if (refp) return refp;
}
if (nodep->op3p()) {
refp = findVarRefRecurse(nodep->op3p());
if (refp) return refp;
}
if (nodep->op3p()) {
refp = findVarRefRecurse(nodep->op3p());
if (refp) return refp;
}
if (nodep->nextp()) {
refp = findVarRefRecurse(nodep->nextp());
if (refp) return refp;
}
return NULL;
}
void findImplicit(AstNodeAssign* nodep) {
if (m_assignp) nodep->v3fatalSrc("Found a NodeAssign under another NodeAssign");
m_assignp = nodep;
m_assignError = false;
m_extend = false;
nodep->user1(true);
// Record the LHS Var so we can check if the Var on the RHS is the same
m_lhsVarRefp = findVarRefRecurse(nodep->lhsp());
if (!m_lhsVarRefp) nodep->v3fatalSrc("Couldn't find a VarRef on the LHSP of an Assign");
// Iterate children looking for ArraySel nodes. From that we get the number of elements
// in the array so we know how many times we need to clone this assignment.
nodep->iterateChildren(*this);
if (nodep->user2() > 1) SliceCloneVisitor scv(nodep);
m_assignp = NULL;
}
virtual void visit(AstNodeAssign* nodep, AstNUser*) {
if (!nodep->user1()) {
// Hasn't been searched for implicit slices yet
findImplicit(nodep);
}
}
void expandUniOp(AstNodeUniop* nodep) {
nodep->user1(true);
unsigned dim = 0;
if (AstArraySel* selp = nodep->lhsp()->castArraySel()) {
// We have explicit dimensions, either packed or unpacked
dim = explicitDimensions(selp);
}
if (dim == 0 && !nodep->lhsp()->castVarRef()) {
// No ArraySel or VarRef, not something we can expand
nodep->iterateChildren(*this);
} else {
AstVarRef* refp = findVarRefRecurse(nodep->lhsp());
ArrayDimensions varDim = refp->varp()->dtypep()->dimensions(false);
if ((int)(dim - varDim.second) < 0) {
// Unpacked dimensions are referenced first, make sure we have them all
nodep->v3error("Unary operator used across unpacked dimensions");
} else if ((int)(dim - (varDim.second)) < 0) {
// Implicit packed dimensions are allowed, make them explicit
uint32_t newDim = (varDim.second) - dim;
AstNode* clonep = nodep->lhsp()->cloneTree(false);
clonep->user1p(refp);
AstNode* newp = insertImplicit(clonep, dim+1, newDim);
nodep->lhsp()->replaceWith(newp); refp = NULL;
int clones = countClones(nodep->lhsp()->castArraySel());
nodep->user2(clones);
SliceCloneVisitor scv(nodep);
}
}
}
virtual void visit(AstRedOr* nodep, AstNUser*) {
if (!nodep->user1()) {
expandUniOp(nodep);
}
}
virtual void visit(AstRedAnd* nodep, AstNUser*) {
if (!nodep->user1()) {
expandUniOp(nodep);
}
}
virtual void visit(AstRedXor* nodep, AstNUser*) {
if (!nodep->user1()) {
expandUniOp(nodep);
}
}
virtual void visit(AstRedXnor* nodep, AstNUser*) {
if (!nodep->user1()) {
expandUniOp(nodep);
}
}
virtual void visit(AstNode* nodep, AstNUser*) {
// Default: Just iterate
nodep->iterateChildren(*this);
}
public:
// CONSTUCTORS
SliceVisitor(AstNetlist* rootp) {
m_assignp = NULL;
m_lhsVarRefp = NULL;
rootp->accept(*this);
}
virtual ~SliceVisitor() {}
};
//######################################################################
// Link class functions
void V3Slice::sliceAll(AstNetlist* rootp) {
UINFO(2,__FUNCTION__<<": "<<endl);
SliceVisitor visitor(rootp);
}