llvm-6502/utils/TableGen/SetTheory.cpp
2011-12-20 02:50:00 +00:00

281 lines
8.6 KiB
C++

//===- SetTheory.cpp - Generate ordered sets from DAG expressions ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the SetTheory class that computes ordered sets of
// Records from DAG expressions.
//
//===----------------------------------------------------------------------===//
#include "SetTheory.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/Support/Format.h"
using namespace llvm;
// Define the standard operators.
namespace {
typedef SetTheory::RecSet RecSet;
typedef SetTheory::RecVec RecVec;
// (add a, b, ...) Evaluate and union all arguments.
struct AddOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts) {
ST.evaluate(Expr->arg_begin(), Expr->arg_end(), Elts);
}
};
// (sub Add, Sub, ...) Set difference.
struct SubOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts) {
if (Expr->arg_size() < 2)
throw "Set difference needs at least two arguments: " +
Expr->getAsString();
RecSet Add, Sub;
ST.evaluate(*Expr->arg_begin(), Add);
ST.evaluate(Expr->arg_begin() + 1, Expr->arg_end(), Sub);
for (RecSet::iterator I = Add.begin(), E = Add.end(); I != E; ++I)
if (!Sub.count(*I))
Elts.insert(*I);
}
};
// (and S1, S2) Set intersection.
struct AndOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts) {
if (Expr->arg_size() != 2)
throw "Set intersection requires two arguments: " + Expr->getAsString();
RecSet S1, S2;
ST.evaluate(Expr->arg_begin()[0], S1);
ST.evaluate(Expr->arg_begin()[1], S2);
for (RecSet::iterator I = S1.begin(), E = S1.end(); I != E; ++I)
if (S2.count(*I))
Elts.insert(*I);
}
};
// SetIntBinOp - Abstract base class for (Op S, N) operators.
struct SetIntBinOp : public SetTheory::Operator {
virtual void apply2(SetTheory &ST, DagInit *Expr,
RecSet &Set, int64_t N,
RecSet &Elts) =0;
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts) {
if (Expr->arg_size() != 2)
throw "Operator requires (Op Set, Int) arguments: " + Expr->getAsString();
RecSet Set;
ST.evaluate(Expr->arg_begin()[0], Set);
IntInit *II = dynamic_cast<IntInit*>(Expr->arg_begin()[1]);
if (!II)
throw "Second argument must be an integer: " + Expr->getAsString();
apply2(ST, Expr, Set, II->getValue(), Elts);
}
};
// (shl S, N) Shift left, remove the first N elements.
struct ShlOp : public SetIntBinOp {
void apply2(SetTheory &ST, DagInit *Expr,
RecSet &Set, int64_t N,
RecSet &Elts) {
if (N < 0)
throw "Positive shift required: " + Expr->getAsString();
if (unsigned(N) < Set.size())
Elts.insert(Set.begin() + N, Set.end());
}
};
// (trunc S, N) Truncate after the first N elements.
struct TruncOp : public SetIntBinOp {
void apply2(SetTheory &ST, DagInit *Expr,
RecSet &Set, int64_t N,
RecSet &Elts) {
if (N < 0)
throw "Positive length required: " + Expr->getAsString();
if (unsigned(N) > Set.size())
N = Set.size();
Elts.insert(Set.begin(), Set.begin() + N);
}
};
// Left/right rotation.
struct RotOp : public SetIntBinOp {
const bool Reverse;
RotOp(bool Rev) : Reverse(Rev) {}
void apply2(SetTheory &ST, DagInit *Expr,
RecSet &Set, int64_t N,
RecSet &Elts) {
if (Reverse)
N = -N;
// N > 0 -> rotate left, N < 0 -> rotate right.
if (Set.empty())
return;
if (N < 0)
N = Set.size() - (-N % Set.size());
else
N %= Set.size();
Elts.insert(Set.begin() + N, Set.end());
Elts.insert(Set.begin(), Set.begin() + N);
}
};
// (decimate S, N) Pick every N'th element of S.
struct DecimateOp : public SetIntBinOp {
void apply2(SetTheory &ST, DagInit *Expr,
RecSet &Set, int64_t N,
RecSet &Elts) {
if (N <= 0)
throw "Positive stride required: " + Expr->getAsString();
for (unsigned I = 0; I < Set.size(); I += N)
Elts.insert(Set[I]);
}
};
// (sequence "Format", From, To) Generate a sequence of records by name.
struct SequenceOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts) {
if (Expr->arg_size() != 3)
throw "Bad args to (sequence \"Format\", From, To): " +
Expr->getAsString();
std::string Format;
if (StringInit *SI = dynamic_cast<StringInit*>(Expr->arg_begin()[0]))
Format = SI->getValue();
else
throw "Format must be a string: " + Expr->getAsString();
int64_t From, To;
if (IntInit *II = dynamic_cast<IntInit*>(Expr->arg_begin()[1]))
From = II->getValue();
else
throw "From must be an integer: " + Expr->getAsString();
if (From < 0 || From >= (1 << 30))
throw "From out of range";
if (IntInit *II = dynamic_cast<IntInit*>(Expr->arg_begin()[2]))
To = II->getValue();
else
throw "From must be an integer: " + Expr->getAsString();
if (To < 0 || To >= (1 << 30))
throw "To out of range";
RecordKeeper &Records =
dynamic_cast<DefInit&>(*Expr->getOperator()).getDef()->getRecords();
int Step = From <= To ? 1 : -1;
for (To += Step; From != To; From += Step) {
std::string Name;
raw_string_ostream OS(Name);
OS << format(Format.c_str(), unsigned(From));
Record *Rec = Records.getDef(OS.str());
if (!Rec)
throw "No def named '" + Name + "': " + Expr->getAsString();
// Try to reevaluate Rec in case it is a set.
if (const RecVec *Result = ST.expand(Rec))
Elts.insert(Result->begin(), Result->end());
else
Elts.insert(Rec);
}
}
};
// Expand a Def into a set by evaluating one of its fields.
struct FieldExpander : public SetTheory::Expander {
StringRef FieldName;
FieldExpander(StringRef fn) : FieldName(fn) {}
void expand(SetTheory &ST, Record *Def, RecSet &Elts) {
ST.evaluate(Def->getValueInit(FieldName), Elts);
}
};
} // end anonymous namespace
void SetTheory::Operator::anchor() { }
void SetTheory::Expander::anchor() { }
SetTheory::SetTheory() {
addOperator("add", new AddOp);
addOperator("sub", new SubOp);
addOperator("and", new AndOp);
addOperator("shl", new ShlOp);
addOperator("trunc", new TruncOp);
addOperator("rotl", new RotOp(false));
addOperator("rotr", new RotOp(true));
addOperator("decimate", new DecimateOp);
addOperator("sequence", new SequenceOp);
}
void SetTheory::addOperator(StringRef Name, Operator *Op) {
Operators[Name] = Op;
}
void SetTheory::addExpander(StringRef ClassName, Expander *E) {
Expanders[ClassName] = E;
}
void SetTheory::addFieldExpander(StringRef ClassName, StringRef FieldName) {
addExpander(ClassName, new FieldExpander(FieldName));
}
void SetTheory::evaluate(Init *Expr, RecSet &Elts) {
// A def in a list can be a just an element, or it may expand.
if (DefInit *Def = dynamic_cast<DefInit*>(Expr)) {
if (const RecVec *Result = expand(Def->getDef()))
return Elts.insert(Result->begin(), Result->end());
Elts.insert(Def->getDef());
return;
}
// Lists simply expand.
if (ListInit *LI = dynamic_cast<ListInit*>(Expr))
return evaluate(LI->begin(), LI->end(), Elts);
// Anything else must be a DAG.
DagInit *DagExpr = dynamic_cast<DagInit*>(Expr);
if (!DagExpr)
throw "Invalid set element: " + Expr->getAsString();
DefInit *OpInit = dynamic_cast<DefInit*>(DagExpr->getOperator());
if (!OpInit)
throw "Bad set expression: " + Expr->getAsString();
Operator *Op = Operators.lookup(OpInit->getDef()->getName());
if (!Op)
throw "Unknown set operator: " + Expr->getAsString();
Op->apply(*this, DagExpr, Elts);
}
const RecVec *SetTheory::expand(Record *Set) {
// Check existing entries for Set and return early.
ExpandMap::iterator I = Expansions.find(Set);
if (I != Expansions.end())
return &I->second;
// This is the first time we see Set. Find a suitable expander.
try {
const std::vector<Record*> &SC = Set->getSuperClasses();
for (unsigned i = 0, e = SC.size(); i != e; ++i)
if (Expander *Exp = Expanders.lookup(SC[i]->getName())) {
// This breaks recursive definitions.
RecVec &EltVec = Expansions[Set];
RecSet Elts;
Exp->expand(*this, Set, Elts);
EltVec.assign(Elts.begin(), Elts.end());
return &EltVec;
}
} catch (const std::string &Error) {
throw TGError(Set->getLoc(), Error);
}
// Set is not expandable.
return 0;
}