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//===- SetTheory.cpp - Generate ordered sets from DAG expressions ---------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the SetTheory class that computes ordered sets of
// Records from DAG expressions.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/SMLoc.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/SetTheory.h"
#include <algorithm>
#include <cstdint>
#include <string>
#include <utility>
using namespace llvm;
// Define the standard operators.
namespace {
using RecSet = SetTheory::RecSet;
using RecVec = SetTheory::RecVec;
// (add a, b, ...) Evaluate and union all arguments.
struct AddOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts,
ArrayRef<SMLoc> Loc) override {
ST.evaluate(Expr->arg_begin(), Expr->arg_end(), Elts, Loc);
}
};
// (sub Add, Sub, ...) Set difference.
struct SubOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts,
ArrayRef<SMLoc> Loc) override {
if (Expr->arg_size() < 2)
PrintFatalError(Loc, "Set difference needs at least two arguments: " +
Expr->getAsString());
RecSet Add, Sub;
ST.evaluate(*Expr->arg_begin(), Add, Loc);
ST.evaluate(Expr->arg_begin() + 1, Expr->arg_end(), Sub, Loc);
for (const auto &I : Add)
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,
ArrayRef<SMLoc> Loc) override {
if (Expr->arg_size() != 2)
PrintFatalError(Loc, "Set intersection requires two arguments: " +
Expr->getAsString());
RecSet S1, S2;
ST.evaluate(Expr->arg_begin()[0], S1, Loc);
ST.evaluate(Expr->arg_begin()[1], S2, Loc);
for (const auto &I : S1)
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, ArrayRef<SMLoc> Loc) = 0;
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts,
ArrayRef<SMLoc> Loc) override {
if (Expr->arg_size() != 2)
PrintFatalError(Loc, "Operator requires (Op Set, Int) arguments: " +
Expr->getAsString());
RecSet Set;
ST.evaluate(Expr->arg_begin()[0], Set, Loc);
IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[1]);
if (!II)
PrintFatalError(Loc, "Second argument must be an integer: " +
Expr->getAsString());
apply2(ST, Expr, Set, II->getValue(), Elts, Loc);
}
};
// (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, ArrayRef<SMLoc> Loc) override {
if (N < 0)
PrintFatalError(Loc, "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, ArrayRef<SMLoc> Loc) override {
if (N < 0)
PrintFatalError(Loc, "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, ArrayRef<SMLoc> Loc) override {
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, ArrayRef<SMLoc> Loc) override {
if (N <= 0)
PrintFatalError(Loc, "Positive stride required: " +
Expr->getAsString());
for (unsigned I = 0; I < Set.size(); I += N)
Elts.insert(Set[I]);
}
};
// (interleave S1, S2, ...) Interleave elements of the arguments.
struct InterleaveOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts,
ArrayRef<SMLoc> Loc) override {
// Evaluate the arguments individually.
SmallVector<RecSet, 4> Args(Expr->getNumArgs());
unsigned MaxSize = 0;
for (unsigned i = 0, e = Expr->getNumArgs(); i != e; ++i) {
ST.evaluate(Expr->getArg(i), Args[i], Loc);
MaxSize = std::max(MaxSize, unsigned(Args[i].size()));
}
// Interleave arguments into Elts.
for (unsigned n = 0; n != MaxSize; ++n)
for (unsigned i = 0, e = Expr->getNumArgs(); i != e; ++i)
if (n < Args[i].size())
Elts.insert(Args[i][n]);
}
};
// (sequence "Format", From, To) Generate a sequence of records by name.
struct SequenceOp : public SetTheory::Operator {
void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts,
ArrayRef<SMLoc> Loc) override {
int Step = 1;
if (Expr->arg_size() > 4)
PrintFatalError(Loc, "Bad args to (sequence \"Format\", From, To): " +
Expr->getAsString());
else if (Expr->arg_size() == 4) {
if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[3])) {
Step = II->getValue();
} else
PrintFatalError(Loc, "Stride must be an integer: " +
Expr->getAsString());
}
std::string Format;
if (StringInit *SI = dyn_cast<StringInit>(Expr->arg_begin()[0]))
Format = std::string(SI->getValue());
else
PrintFatalError(Loc, "Format must be a string: " + Expr->getAsString());
int64_t From, To;
if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[1]))
From = II->getValue();
else
PrintFatalError(Loc, "From must be an integer: " + Expr->getAsString());
if (From < 0 || From >= (1 << 30))
PrintFatalError(Loc, "From out of range");
if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[2]))
To = II->getValue();
else
PrintFatalError(Loc, "To must be an integer: " + Expr->getAsString());
if (To < 0 || To >= (1 << 30))
PrintFatalError(Loc, "To out of range");
RecordKeeper &Records =
cast<DefInit>(Expr->getOperator())->getDef()->getRecords();
Step *= From <= To ? 1 : -1;
while (true) {
if (Step > 0 && From > To)
break;
else if (Step < 0 && From < To)
break;
std::string Name;
raw_string_ostream OS(Name);
OS << format(Format.c_str(), unsigned(From));
Record *Rec = Records.getDef(OS.str());
if (!Rec)
PrintFatalError(Loc, "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);
From += Step;
}
}
};
// 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) override {
ST.evaluate(Def->getValueInit(FieldName), Elts, Def->getLoc());
}
};
} // end anonymous namespace
// Pin the vtables to this file.
void SetTheory::Operator::anchor() {}
void SetTheory::Expander::anchor() {}
SetTheory::SetTheory() {
addOperator("add", std::make_unique<AddOp>());
addOperator("sub", std::make_unique<SubOp>());
addOperator("and", std::make_unique<AndOp>());
addOperator("shl", std::make_unique<ShlOp>());
addOperator("trunc", std::make_unique<TruncOp>());
addOperator("rotl", std::make_unique<RotOp>(false));
addOperator("rotr", std::make_unique<RotOp>(true));
addOperator("decimate", std::make_unique<DecimateOp>());
addOperator("interleave", std::make_unique<InterleaveOp>());
addOperator("sequence", std::make_unique<SequenceOp>());
}
void SetTheory::addOperator(StringRef Name, std::unique_ptr<Operator> Op) {
Operators[Name] = std::move(Op);
}
void SetTheory::addExpander(StringRef ClassName, std::unique_ptr<Expander> E) {
Expanders[ClassName] = std::move(E);
}
void SetTheory::addFieldExpander(StringRef ClassName, StringRef FieldName) {
addExpander(ClassName, std::make_unique<FieldExpander>(FieldName));
}
void SetTheory::evaluate(Init *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
// A def in a list can be a just an element, or it may expand.
if (DefInit *Def = dyn_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 = dyn_cast<ListInit>(Expr))
return evaluate(LI->begin(), LI->end(), Elts, Loc);
// Anything else must be a DAG.
DagInit *DagExpr = dyn_cast<DagInit>(Expr);
if (!DagExpr)
PrintFatalError(Loc, "Invalid set element: " + Expr->getAsString());
DefInit *OpInit = dyn_cast<DefInit>(DagExpr->getOperator());
if (!OpInit)
PrintFatalError(Loc, "Bad set expression: " + Expr->getAsString());
auto I = Operators.find(OpInit->getDef()->getName());
if (I == Operators.end())
PrintFatalError(Loc, "Unknown set operator: " + Expr->getAsString());
I->second->apply(*this, DagExpr, Elts, Loc);
}
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.
ArrayRef<std::pair<Record *, SMRange>> SC = Set->getSuperClasses();
for (const auto &SCPair : SC) {
// Skip unnamed superclasses.
if (!isa<StringInit>(SCPair.first->getNameInit()))
continue;
auto I = Expanders.find(SCPair.first->getName());
if (I != Expanders.end()) {
// This breaks recursive definitions.
RecVec &EltVec = Expansions[Set];
RecSet Elts;
I->second->expand(*this, Set, Elts);
EltVec.assign(Elts.begin(), Elts.end());
return &EltVec;
}
}
// Set is not expandable.
return nullptr;
}