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llvm-mirror/utils/TableGen/GICombinerEmitter.cpp
Daniel Sanders a5cc32cb61 [gicombiner] Allow disable-rule option to disable all-except-... 
Summary:
Adds two features to the generated rule disable option:
- '*' - Disable all rules
- '!<foo>' - Re-enable rule(s)
  - '!foo' - Enable rule named 'foo'
  - '!5' - Enable rule five
  - '!4-9' - Enable rule four to nine
  - '!foo-bar' - Enable rules from 'foo' to (and including) 'bar'
(the '!' is available to the generated disable option but is not part of the underlying and determines whether to call setRuleDisabled() or setRuleEnabled())

This is intended to support unit testing of combine rules so
that you can do:
  GeneratedCfg.setRuleDisabled("*")
  GeneratedCfg.setRuleEnabled("foo")
to ensure only a specific rule is in effect. The rule is still
required to be included in a combiner though

Also added --...-only-enable-rule=X,Y which is effectively an
alias for --...-disable-rule=*,!X,!Y and as such interacts
properly with disable-rule.

Reviewers: aditya_nandakumar, bogner, volkan, aemerson, paquette, arsenm

Subscribers: wdng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81889
2020-06-16 16:57:16 -07:00

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//===- GlobalCombinerEmitter.cpp - Generate a combiner --------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
/// \file Generate a combiner implementation for GlobalISel from a declarative
/// syntax
///
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ScopedPrinter.h"
#include "llvm/Support/Timer.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/StringMatcher.h"
#include "llvm/TableGen/TableGenBackend.h"
#include "CodeGenTarget.h"
#include "GlobalISel/CodeExpander.h"
#include "GlobalISel/CodeExpansions.h"
#include "GlobalISel/GIMatchDag.h"
#include "GlobalISel/GIMatchTree.h"
#include <cstdint>
using namespace llvm;
#define DEBUG_TYPE "gicombiner-emitter"
// FIXME: Use ALWAYS_ENABLED_STATISTIC once it's available.
unsigned NumPatternTotal = 0;
STATISTIC(NumPatternTotalStatistic, "Total number of patterns");
cl::OptionCategory
GICombinerEmitterCat("Options for -gen-global-isel-combiner");
static cl::list<std::string>
SelectedCombiners("combiners", cl::desc("Emit the specified combiners"),
cl::cat(GICombinerEmitterCat), cl::CommaSeparated);
static cl::opt<bool> ShowExpansions(
"gicombiner-show-expansions",
cl::desc("Use C++ comments to indicate occurence of code expansion"),
cl::cat(GICombinerEmitterCat));
static cl::opt<bool> StopAfterParse(
"gicombiner-stop-after-parse",
cl::desc("Stop processing after parsing rules and dump state"),
cl::cat(GICombinerEmitterCat));
static cl::opt<bool> StopAfterBuild(
"gicombiner-stop-after-build",
cl::desc("Stop processing after building the match tree"),
cl::cat(GICombinerEmitterCat));
namespace {
typedef uint64_t RuleID;
// We're going to be referencing the same small strings quite a lot for operand
// names and the like. Make their lifetime management simple with a global
// string table.
StringSet<> StrTab;
StringRef insertStrTab(StringRef S) {
if (S.empty())
return S;
return StrTab.insert(S).first->first();
}
class format_partition_name {
const GIMatchTree &Tree;
unsigned Idx;
public:
format_partition_name(const GIMatchTree &Tree, unsigned Idx)
: Tree(Tree), Idx(Idx) {}
void print(raw_ostream &OS) const {
Tree.getPartitioner()->emitPartitionName(OS, Idx);
}
};
raw_ostream &operator<<(raw_ostream &OS, const format_partition_name &Fmt) {
Fmt.print(OS);
return OS;
}
/// Declares data that is passed from the match stage to the apply stage.
class MatchDataInfo {
/// The symbol used in the tablegen patterns
StringRef PatternSymbol;
/// The data type for the variable
StringRef Type;
/// The name of the variable as declared in the generated matcher.
std::string VariableName;
public:
MatchDataInfo(StringRef PatternSymbol, StringRef Type, StringRef VariableName)
: PatternSymbol(PatternSymbol), Type(Type), VariableName(VariableName) {}
StringRef getPatternSymbol() const { return PatternSymbol; };
StringRef getType() const { return Type; };
StringRef getVariableName() const { return VariableName; };
};
class RootInfo {
StringRef PatternSymbol;
public:
RootInfo(StringRef PatternSymbol) : PatternSymbol(PatternSymbol) {}
StringRef getPatternSymbol() const { return PatternSymbol; }
};
class CombineRule {
public:
using const_matchdata_iterator = std::vector<MatchDataInfo>::const_iterator;
struct VarInfo {
const GIMatchDagInstr *N;
const GIMatchDagOperand *Op;
const DagInit *Matcher;
public:
VarInfo(const GIMatchDagInstr *N, const GIMatchDagOperand *Op,
const DagInit *Matcher)
: N(N), Op(Op), Matcher(Matcher) {}
};
protected:
/// A unique ID for this rule
/// ID's are used for debugging and run-time disabling of rules among other
/// things.
RuleID ID;
/// A unique ID that can be used for anonymous objects belonging to this rule.
/// Used to create unique names in makeNameForAnon*() without making tests
/// overly fragile.
unsigned UID = 0;
/// The record defining this rule.
const Record &TheDef;
/// The roots of a match. These are the leaves of the DAG that are closest to
/// the end of the function. I.e. the nodes that are encountered without
/// following any edges of the DAG described by the pattern as we work our way
/// from the bottom of the function to the top.
std::vector<RootInfo> Roots;
GIMatchDag MatchDag;
/// A block of arbitrary C++ to finish testing the match.
/// FIXME: This is a temporary measure until we have actual pattern matching
const CodeInit *MatchingFixupCode = nullptr;
/// The MatchData defined by the match stage and required by the apply stage.
/// This allows the plumbing of arbitrary data from C++ predicates between the
/// stages.
///
/// For example, suppose you have:
/// %A = <some-constant-expr>
/// %0 = G_ADD %1, %A
/// you could define a GIMatchPredicate that walks %A, constant folds as much
/// as possible and returns an APInt containing the discovered constant. You
/// could then declare:
/// def apint : GIDefMatchData<"APInt">;
/// add it to the rule with:
/// (defs root:$root, apint:$constant)
/// evaluate it in the pattern with a C++ function that takes a
/// MachineOperand& and an APInt& with:
/// (match [{MIR %root = G_ADD %0, %A }],
/// (constantfold operand:$A, apint:$constant))
/// and finally use it in the apply stage with:
/// (apply (create_operand
/// [{ MachineOperand::CreateImm(${constant}.getZExtValue());
/// ]}, apint:$constant),
/// [{MIR %root = FOO %0, %constant }])
std::vector<MatchDataInfo> MatchDataDecls;
void declareMatchData(StringRef PatternSymbol, StringRef Type,
StringRef VarName);
bool parseInstructionMatcher(const CodeGenTarget &Target, StringInit *ArgName,
const Init &Arg,
StringMap<std::vector<VarInfo>> &NamedEdgeDefs,
StringMap<std::vector<VarInfo>> &NamedEdgeUses);
bool parseWipMatchOpcodeMatcher(const CodeGenTarget &Target,
StringInit *ArgName, const Init &Arg);
public:
CombineRule(const CodeGenTarget &Target, GIMatchDagContext &Ctx, RuleID ID,
const Record &R)
: ID(ID), TheDef(R), MatchDag(Ctx) {}
CombineRule(const CombineRule &) = delete;
bool parseDefs();
bool parseMatcher(const CodeGenTarget &Target);
RuleID getID() const { return ID; }
unsigned allocUID() { return UID++; }
StringRef getName() const { return TheDef.getName(); }
const Record &getDef() const { return TheDef; }
const CodeInit *getMatchingFixupCode() const { return MatchingFixupCode; }
size_t getNumRoots() const { return Roots.size(); }
GIMatchDag &getMatchDag() { return MatchDag; }
const GIMatchDag &getMatchDag() const { return MatchDag; }
using const_root_iterator = std::vector<RootInfo>::const_iterator;
const_root_iterator roots_begin() const { return Roots.begin(); }
const_root_iterator roots_end() const { return Roots.end(); }
iterator_range<const_root_iterator> roots() const {
return llvm::make_range(Roots.begin(), Roots.end());
}
iterator_range<const_matchdata_iterator> matchdata_decls() const {
return make_range(MatchDataDecls.begin(), MatchDataDecls.end());
}
/// Export expansions for this rule
void declareExpansions(CodeExpansions &Expansions) const {
for (const auto &I : matchdata_decls())
Expansions.declare(I.getPatternSymbol(), I.getVariableName());
}
/// The matcher will begin from the roots and will perform the match by
/// traversing the edges to cover the whole DAG. This function reverses DAG
/// edges such that everything is reachable from a root. This is part of the
/// preparation work for flattening the DAG into a tree.
void reorientToRoots() {
SmallSet<const GIMatchDagInstr *, 5> Roots;
SmallSet<const GIMatchDagInstr *, 5> Visited;
SmallSet<GIMatchDagEdge *, 20> EdgesRemaining;
for (auto &I : MatchDag.roots()) {
Roots.insert(I);
Visited.insert(I);
}
for (auto &I : MatchDag.edges())
EdgesRemaining.insert(I);
bool Progressed = false;
SmallSet<GIMatchDagEdge *, 20> EdgesToRemove;
while (!EdgesRemaining.empty()) {
for (auto EI = EdgesRemaining.begin(), EE = EdgesRemaining.end();
EI != EE; ++EI) {
if (Visited.count((*EI)->getFromMI())) {
if (Roots.count((*EI)->getToMI()))
PrintError(TheDef.getLoc(), "One or more roots are unnecessary");
Visited.insert((*EI)->getToMI());
EdgesToRemove.insert(*EI);
Progressed = true;
}
}
for (GIMatchDagEdge *ToRemove : EdgesToRemove)
EdgesRemaining.erase(ToRemove);
EdgesToRemove.clear();
for (auto EI = EdgesRemaining.begin(), EE = EdgesRemaining.end();
EI != EE; ++EI) {
if (Visited.count((*EI)->getToMI())) {
(*EI)->reverse();
Visited.insert((*EI)->getToMI());
EdgesToRemove.insert(*EI);
Progressed = true;
}
for (GIMatchDagEdge *ToRemove : EdgesToRemove)
EdgesRemaining.erase(ToRemove);
EdgesToRemove.clear();
}
if (!Progressed) {
LLVM_DEBUG(dbgs() << "No progress\n");
return;
}
Progressed = false;
}
}
};
/// A convenience function to check that an Init refers to a specific def. This
/// is primarily useful for testing for defs and similar in DagInit's since
/// DagInit's support any type inside them.
static bool isSpecificDef(const Init &N, StringRef Def) {
if (const DefInit *OpI = dyn_cast<DefInit>(&N))
if (OpI->getDef()->getName() == Def)
return true;
return false;
}
/// A convenience function to check that an Init refers to a def that is a
/// subclass of the given class and coerce it to a def if it is. This is
/// primarily useful for testing for subclasses of GIMatchKind and similar in
/// DagInit's since DagInit's support any type inside them.
static Record *getDefOfSubClass(const Init &N, StringRef Cls) {
if (const DefInit *OpI = dyn_cast<DefInit>(&N))
if (OpI->getDef()->isSubClassOf(Cls))
return OpI->getDef();
return nullptr;
}
/// A convenience function to check that an Init refers to a dag whose operator
/// is a specific def and coerce it to a dag if it is. This is primarily useful
/// for testing for subclasses of GIMatchKind and similar in DagInit's since
/// DagInit's support any type inside them.
static const DagInit *getDagWithSpecificOperator(const Init &N,
StringRef Name) {
if (const DagInit *I = dyn_cast<DagInit>(&N))
if (I->getNumArgs() > 0)
if (const DefInit *OpI = dyn_cast<DefInit>(I->getOperator()))
if (OpI->getDef()->getName() == Name)
return I;
return nullptr;
}
/// A convenience function to check that an Init refers to a dag whose operator
/// is a def that is a subclass of the given class and coerce it to a dag if it
/// is. This is primarily useful for testing for subclasses of GIMatchKind and
/// similar in DagInit's since DagInit's support any type inside them.
static const DagInit *getDagWithOperatorOfSubClass(const Init &N,
StringRef Cls) {
if (const DagInit *I = dyn_cast<DagInit>(&N))
if (I->getNumArgs() > 0)
if (const DefInit *OpI = dyn_cast<DefInit>(I->getOperator()))
if (OpI->getDef()->isSubClassOf(Cls))
return I;
return nullptr;
}
StringRef makeNameForAnonInstr(CombineRule &Rule) {
return insertStrTab(to_string(
format("__anon%" PRIu64 "_%u", Rule.getID(), Rule.allocUID())));
}
StringRef makeDebugName(CombineRule &Rule, StringRef Name) {
return insertStrTab(Name.empty() ? makeNameForAnonInstr(Rule) : StringRef(Name));
}
StringRef makeNameForAnonPredicate(CombineRule &Rule) {
return insertStrTab(to_string(
format("__anonpred%" PRIu64 "_%u", Rule.getID(), Rule.allocUID())));
}
void CombineRule::declareMatchData(StringRef PatternSymbol, StringRef Type,
StringRef VarName) {
MatchDataDecls.emplace_back(PatternSymbol, Type, VarName);
}
bool CombineRule::parseDefs() {
NamedRegionTimer T("parseDefs", "Time spent parsing the defs", "Rule Parsing",
"Time spent on rule parsing", TimeRegions);
DagInit *Defs = TheDef.getValueAsDag("Defs");
if (Defs->getOperatorAsDef(TheDef.getLoc())->getName() != "defs") {
PrintError(TheDef.getLoc(), "Expected defs operator");
return false;
}
for (unsigned I = 0, E = Defs->getNumArgs(); I < E; ++I) {
// Roots should be collected into Roots
if (isSpecificDef(*Defs->getArg(I), "root")) {
Roots.emplace_back(Defs->getArgNameStr(I));
continue;
}
// Subclasses of GIDefMatchData should declare that this rule needs to pass
// data from the match stage to the apply stage, and ensure that the
// generated matcher has a suitable variable for it to do so.
if (Record *MatchDataRec =
getDefOfSubClass(*Defs->getArg(I), "GIDefMatchData")) {
declareMatchData(Defs->getArgNameStr(I),
MatchDataRec->getValueAsString("Type"),
llvm::to_string(llvm::format("MatchData%" PRIu64, ID)));
continue;
}
// Otherwise emit an appropriate error message.
if (getDefOfSubClass(*Defs->getArg(I), "GIDefKind"))
PrintError(TheDef.getLoc(),
"This GIDefKind not implemented in tablegen");
else if (getDefOfSubClass(*Defs->getArg(I), "GIDefKindWithArgs"))
PrintError(TheDef.getLoc(),
"This GIDefKindWithArgs not implemented in tablegen");
else
PrintError(TheDef.getLoc(),
"Expected a subclass of GIDefKind or a sub-dag whose "
"operator is of type GIDefKindWithArgs");
return false;
}
if (Roots.empty()) {
PrintError(TheDef.getLoc(), "Combine rules must have at least one root");
return false;
}
return true;
}
// Parse an (Instruction $a:Arg1, $b:Arg2, ...) matcher. Edges are formed
// between matching operand names between different matchers.
bool CombineRule::parseInstructionMatcher(
const CodeGenTarget &Target, StringInit *ArgName, const Init &Arg,
StringMap<std::vector<VarInfo>> &NamedEdgeDefs,
StringMap<std::vector<VarInfo>> &NamedEdgeUses) {
if (const DagInit *Matcher =
getDagWithOperatorOfSubClass(Arg, "Instruction")) {
auto &Instr =
Target.getInstruction(Matcher->getOperatorAsDef(TheDef.getLoc()));
StringRef Name = ArgName ? ArgName->getValue() : "";
GIMatchDagInstr *N =
MatchDag.addInstrNode(makeDebugName(*this, Name), insertStrTab(Name),
MatchDag.getContext().makeOperandList(Instr));
N->setOpcodeAnnotation(&Instr);
const auto &P = MatchDag.addPredicateNode<GIMatchDagOpcodePredicate>(
makeNameForAnonPredicate(*this), Instr);
MatchDag.addPredicateDependency(N, nullptr, P, &P->getOperandInfo()["mi"]);
unsigned OpIdx = 0;
for (const auto &NameInit : Matcher->getArgNames()) {
StringRef Name = insertStrTab(NameInit->getAsUnquotedString());
if (Name.empty())
continue;
N->assignNameToOperand(OpIdx, Name);
// Record the endpoints of any named edges. We'll add the cartesian
// product of edges later.
const auto &InstrOperand = N->getOperandInfo()[OpIdx];
if (InstrOperand.isDef()) {
NamedEdgeDefs.try_emplace(Name);
NamedEdgeDefs[Name].emplace_back(N, &InstrOperand, Matcher);
} else {
NamedEdgeUses.try_emplace(Name);
NamedEdgeUses[Name].emplace_back(N, &InstrOperand, Matcher);
}
if (InstrOperand.isDef()) {
if (find_if(Roots, [&](const RootInfo &X) {
return X.getPatternSymbol() == Name;
}) != Roots.end()) {
N->setMatchRoot();
}
}
OpIdx++;
}
return true;
}
return false;
}
// Parse the wip_match_opcode placeholder that's temporarily present in lieu of
// implementing macros or choices between two matchers.
bool CombineRule::parseWipMatchOpcodeMatcher(const CodeGenTarget &Target,
StringInit *ArgName,
const Init &Arg) {
if (const DagInit *Matcher =
getDagWithSpecificOperator(Arg, "wip_match_opcode")) {
StringRef Name = ArgName ? ArgName->getValue() : "";
GIMatchDagInstr *N =
MatchDag.addInstrNode(makeDebugName(*this, Name), insertStrTab(Name),
MatchDag.getContext().makeEmptyOperandList());
if (find_if(Roots, [&](const RootInfo &X) {
return ArgName && X.getPatternSymbol() == ArgName->getValue();
}) != Roots.end()) {
N->setMatchRoot();
}
const auto &P = MatchDag.addPredicateNode<GIMatchDagOneOfOpcodesPredicate>(
makeNameForAnonPredicate(*this));
MatchDag.addPredicateDependency(N, nullptr, P, &P->getOperandInfo()["mi"]);
// Each argument is an opcode that will pass this predicate. Add them all to
// the predicate implementation
for (const auto &Arg : Matcher->getArgs()) {
Record *OpcodeDef = getDefOfSubClass(*Arg, "Instruction");
if (OpcodeDef) {
P->addOpcode(&Target.getInstruction(OpcodeDef));
continue;
}
PrintError(TheDef.getLoc(),
"Arguments to wip_match_opcode must be instructions");
return false;
}
return true;
}
return false;
}
bool CombineRule::parseMatcher(const CodeGenTarget &Target) {
NamedRegionTimer T("parseMatcher", "Time spent parsing the matcher",
"Rule Parsing", "Time spent on rule parsing", TimeRegions);
StringMap<std::vector<VarInfo>> NamedEdgeDefs;
StringMap<std::vector<VarInfo>> NamedEdgeUses;
DagInit *Matchers = TheDef.getValueAsDag("Match");
if (Matchers->getOperatorAsDef(TheDef.getLoc())->getName() != "match") {
PrintError(TheDef.getLoc(), "Expected match operator");
return false;
}
if (Matchers->getNumArgs() == 0) {
PrintError(TheDef.getLoc(), "Matcher is empty");
return false;
}
// The match section consists of a list of matchers and predicates. Parse each
// one and add the equivalent GIMatchDag nodes, predicates, and edges.
for (unsigned I = 0; I < Matchers->getNumArgs(); ++I) {
if (parseInstructionMatcher(Target, Matchers->getArgName(I),
*Matchers->getArg(I), NamedEdgeDefs,
NamedEdgeUses))
continue;
if (parseWipMatchOpcodeMatcher(Target, Matchers->getArgName(I),
*Matchers->getArg(I)))
continue;
// Parse arbitrary C++ code we have in lieu of supporting MIR matching
if (const CodeInit *CodeI = dyn_cast<CodeInit>(Matchers->getArg(I))) {
assert(!MatchingFixupCode &&
"Only one block of arbitrary code is currently permitted");
MatchingFixupCode = CodeI;
MatchDag.setHasPostMatchPredicate(true);
continue;
}
PrintError(TheDef.getLoc(),
"Expected a subclass of GIMatchKind or a sub-dag whose "
"operator is either of a GIMatchKindWithArgs or Instruction");
PrintNote("Pattern was `" + Matchers->getArg(I)->getAsString() + "'");
return false;
}
// Add the cartesian product of use -> def edges.
bool FailedToAddEdges = false;
for (const auto &NameAndDefs : NamedEdgeDefs) {
if (NameAndDefs.getValue().size() > 1) {
PrintError(TheDef.getLoc(),
"Two different MachineInstrs cannot def the same vreg");
for (const auto &NameAndDefOp : NameAndDefs.getValue())
PrintNote("in " + to_string(*NameAndDefOp.N) + " created from " +
to_string(*NameAndDefOp.Matcher) + "");
FailedToAddEdges = true;
}
const auto &Uses = NamedEdgeUses[NameAndDefs.getKey()];
for (const VarInfo &DefVar : NameAndDefs.getValue()) {
for (const VarInfo &UseVar : Uses) {
MatchDag.addEdge(insertStrTab(NameAndDefs.getKey()), UseVar.N, UseVar.Op,
DefVar.N, DefVar.Op);
}
}
}
if (FailedToAddEdges)
return false;
// If a variable is referenced in multiple use contexts then we need a
// predicate to confirm they are the same operand. We can elide this if it's
// also referenced in a def context and we're traversing the def-use chain
// from the def to the uses but we can't know which direction we're going
// until after reorientToRoots().
for (const auto &NameAndUses : NamedEdgeUses) {
const auto &Uses = NameAndUses.getValue();
if (Uses.size() > 1) {
const auto &LeadingVar = Uses.front();
for (const auto &Var : ArrayRef<VarInfo>(Uses).drop_front()) {
// Add a predicate for each pair until we've covered the whole
// equivalence set. We could test the whole set in a single predicate
// but that means we can't test any equivalence until all the MO's are
// available which can lead to wasted work matching the DAG when this
// predicate can already be seen to have failed.
//
// We have a similar problem due to the need to wait for a particular MO
// before being able to test any of them. However, that is mitigated by
// the order in which we build the DAG. We build from the roots outwards
// so by using the first recorded use in all the predicates, we are
// making the dependency on one of the earliest visited references in
// the DAG. It's not guaranteed once the generated matcher is optimized
// (because the factoring the common portions of rules might change the
// visit order) but this should mean that these predicates depend on the
// first MO to become available.
const auto &P = MatchDag.addPredicateNode<GIMatchDagSameMOPredicate>(
makeNameForAnonPredicate(*this));
MatchDag.addPredicateDependency(LeadingVar.N, LeadingVar.Op, P,
&P->getOperandInfo()["mi0"]);
MatchDag.addPredicateDependency(Var.N, Var.Op, P,
&P->getOperandInfo()["mi1"]);
}
}
}
return true;
}
class GICombinerEmitter {
StringRef Name;
const CodeGenTarget &Target;
Record *Combiner;
std::vector<std::unique_ptr<CombineRule>> Rules;
GIMatchDagContext MatchDagCtx;
std::unique_ptr<CombineRule> makeCombineRule(const Record &R);
void gatherRules(std::vector<std::unique_ptr<CombineRule>> &ActiveRules,
const std::vector<Record *> &&RulesAndGroups);
public:
explicit GICombinerEmitter(RecordKeeper &RK, const CodeGenTarget &Target,
StringRef Name, Record *Combiner);
~GICombinerEmitter() {}
StringRef getClassName() const {
return Combiner->getValueAsString("Classname");
}
void run(raw_ostream &OS);
/// Emit the name matcher (guarded by #ifndef NDEBUG) used to disable rules in
/// response to the generated cl::opt.
void emitNameMatcher(raw_ostream &OS) const;
void generateDeclarationsCodeForTree(raw_ostream &OS, const GIMatchTree &Tree) const;
void generateCodeForTree(raw_ostream &OS, const GIMatchTree &Tree,
StringRef Indent) const;
};
GICombinerEmitter::GICombinerEmitter(RecordKeeper &RK,
const CodeGenTarget &Target,
StringRef Name, Record *Combiner)
: Name(Name), Target(Target), Combiner(Combiner) {}
void GICombinerEmitter::emitNameMatcher(raw_ostream &OS) const {
std::vector<std::pair<std::string, std::string>> Cases;
Cases.reserve(Rules.size());
for (const CombineRule &EnumeratedRule : make_pointee_range(Rules)) {
std::string Code;
raw_string_ostream SS(Code);
SS << "return " << EnumeratedRule.getID() << ";\n";
Cases.push_back(
std::make_pair(std::string(EnumeratedRule.getName()), SS.str()));
}
OS << "static Optional<uint64_t> getRuleIdxForIdentifier(StringRef "
"RuleIdentifier) {\n"
<< " uint64_t I;\n"
<< " // getAtInteger(...) returns false on success\n"
<< " bool Parsed = !RuleIdentifier.getAsInteger(0, I);\n"
<< " if (Parsed)\n"
<< " return I;\n\n"
<< "#ifndef NDEBUG\n";
StringMatcher Matcher("RuleIdentifier", Cases, OS);
Matcher.Emit();
OS << "#endif // ifndef NDEBUG\n\n"
<< " return None;\n"
<< "}\n";
}
std::unique_ptr<CombineRule>
GICombinerEmitter::makeCombineRule(const Record &TheDef) {
std::unique_ptr<CombineRule> Rule =
std::make_unique<CombineRule>(Target, MatchDagCtx, NumPatternTotal, TheDef);
if (!Rule->parseDefs())
return nullptr;
if (!Rule->parseMatcher(Target))
return nullptr;
Rule->reorientToRoots();
LLVM_DEBUG({
dbgs() << "Parsed rule defs/match for '" << Rule->getName() << "'\n";
Rule->getMatchDag().dump();
Rule->getMatchDag().writeDOTGraph(dbgs(), Rule->getName());
});
if (StopAfterParse)
return Rule;
// For now, don't support traversing from def to use. We'll come back to
// this later once we have the algorithm changes to support it.
bool EmittedDefToUseError = false;
for (const auto &E : Rule->getMatchDag().edges()) {
if (E->isDefToUse()) {
if (!EmittedDefToUseError) {
PrintError(
TheDef.getLoc(),
"Generated state machine cannot lookup uses from a def (yet)");
EmittedDefToUseError = true;
}
PrintNote("Node " + to_string(*E->getFromMI()));
PrintNote("Node " + to_string(*E->getToMI()));
PrintNote("Edge " + to_string(*E));
}
}
if (EmittedDefToUseError)
return nullptr;
// For now, don't support multi-root rules. We'll come back to this later
// once we have the algorithm changes to support it.
if (Rule->getNumRoots() > 1) {
PrintError(TheDef.getLoc(), "Multi-root matches are not supported (yet)");
return nullptr;
}
return Rule;
}
/// Recurse into GICombineGroup's and flatten the ruleset into a simple list.
void GICombinerEmitter::gatherRules(
std::vector<std::unique_ptr<CombineRule>> &ActiveRules,
const std::vector<Record *> &&RulesAndGroups) {
for (Record *R : RulesAndGroups) {
if (R->isValueUnset("Rules")) {
std::unique_ptr<CombineRule> Rule = makeCombineRule(*R);
if (Rule == nullptr) {
PrintError(R->getLoc(), "Failed to parse rule");
continue;
}
ActiveRules.emplace_back(std::move(Rule));
++NumPatternTotal;
} else
gatherRules(ActiveRules, R->getValueAsListOfDefs("Rules"));
}
}
void GICombinerEmitter::generateCodeForTree(raw_ostream &OS,
const GIMatchTree &Tree,
StringRef Indent) const {
if (Tree.getPartitioner() != nullptr) {
Tree.getPartitioner()->generatePartitionSelectorCode(OS, Indent);
for (const auto &EnumChildren : enumerate(Tree.children())) {
OS << Indent << "if (Partition == " << EnumChildren.index() << " /* "
<< format_partition_name(Tree, EnumChildren.index()) << " */) {\n";
generateCodeForTree(OS, EnumChildren.value(), (Indent + " ").str());
OS << Indent << "}\n";
}
return;
}
bool AnyFullyTested = false;
for (const auto &Leaf : Tree.possible_leaves()) {
OS << Indent << "// Leaf name: " << Leaf.getName() << "\n";
const CombineRule *Rule = Leaf.getTargetData<CombineRule>();
const Record &RuleDef = Rule->getDef();
OS << Indent << "// Rule: " << RuleDef.getName() << "\n"
<< Indent << "if (!RuleConfig->isRuleDisabled(" << Rule->getID()
<< ")) {\n";
CodeExpansions Expansions;
for (const auto &VarBinding : Leaf.var_bindings()) {
if (VarBinding.isInstr())
Expansions.declare(VarBinding.getName(),
"MIs[" + to_string(VarBinding.getInstrID()) + "]");
else
Expansions.declare(VarBinding.getName(),
"MIs[" + to_string(VarBinding.getInstrID()) +
"]->getOperand(" +
to_string(VarBinding.getOpIdx()) + ")");
}
Rule->declareExpansions(Expansions);
DagInit *Applyer = RuleDef.getValueAsDag("Apply");
if (Applyer->getOperatorAsDef(RuleDef.getLoc())->getName() !=
"apply") {
PrintError(RuleDef.getLoc(), "Expected apply operator");
return;
}
OS << Indent << " if (1\n";
// Attempt to emit code for any untested predicates left over. Note that
// isFullyTested() will remain false even if we succeed here and therefore
// combine rule elision will not be performed. This is because we do not
// know if there's any connection between the predicates for each leaf and
// therefore can't tell if one makes another unreachable. Ideally, the
// partitioner(s) would be sufficiently complete to prevent us from having
// untested predicates left over.
for (const GIMatchDagPredicate *Predicate : Leaf.untested_predicates()) {
if (Predicate->generateCheckCode(OS, (Indent + " ").str(),
Expansions))
continue;
PrintError(RuleDef.getLoc(),
"Unable to test predicate used in rule");
PrintNote(SMLoc(),
"This indicates an incomplete implementation in tablegen");
Predicate->print(errs());
errs() << "\n";
OS << Indent
<< "llvm_unreachable(\"TableGen did not emit complete code for this "
"path\");\n";
break;
}
if (Rule->getMatchingFixupCode() &&
!Rule->getMatchingFixupCode()->getValue().empty()) {
// FIXME: Single-use lambda's like this are a serious compile-time
// performance and memory issue. It's convenient for this early stage to
// defer some work to successive patches but we need to eliminate this
// before the ruleset grows to small-moderate size. Last time, it became
// a big problem for low-mem systems around the 500 rule mark but by the
// time we grow that large we should have merged the ISel match table
// mechanism with the Combiner.
OS << Indent << " && [&]() {\n"
<< Indent << " "
<< CodeExpander(Rule->getMatchingFixupCode()->getValue(), Expansions,
Rule->getMatchingFixupCode()->getLoc(), ShowExpansions)
<< "\n"
<< Indent << " return true;\n"
<< Indent << " }()";
}
OS << ") {\n" << Indent << " ";
if (const CodeInit *Code = dyn_cast<CodeInit>(Applyer->getArg(0))) {
OS << CodeExpander(Code->getAsUnquotedString(), Expansions,
Code->getLoc(), ShowExpansions)
<< "\n"
<< Indent << " return true;\n"
<< Indent << " }\n";
} else {
PrintError(RuleDef.getLoc(), "Expected apply code block");
return;
}
OS << Indent << "}\n";
assert(Leaf.isFullyTraversed());
// If we didn't have any predicates left over and we're not using the
// trap-door we have to support arbitrary C++ code while we're migrating to
// the declarative style then we know that subsequent leaves are
// unreachable.
if (Leaf.isFullyTested() &&
(!Rule->getMatchingFixupCode() ||
Rule->getMatchingFixupCode()->getValue().empty())) {
AnyFullyTested = true;
OS << Indent
<< "llvm_unreachable(\"Combine rule elision was incorrect\");\n"
<< Indent << "return false;\n";
}
}
if (!AnyFullyTested)
OS << Indent << "return false;\n";
}
static void emitAdditionalHelperMethodArguments(raw_ostream &OS,
Record *Combiner) {
for (Record *Arg : Combiner->getValueAsListOfDefs("AdditionalArguments"))
OS << ",\n " << Arg->getValueAsString("Type")
<< Arg->getValueAsString("Name");
}
void GICombinerEmitter::run(raw_ostream &OS) {
gatherRules(Rules, Combiner->getValueAsListOfDefs("Rules"));
if (StopAfterParse) {
MatchDagCtx.print(errs());
PrintNote(Combiner->getLoc(),
"Terminating due to -gicombiner-stop-after-parse");
return;
}
if (ErrorsPrinted)
PrintFatalError(Combiner->getLoc(), "Failed to parse one or more rules");
LLVM_DEBUG(dbgs() << "Optimizing tree for " << Rules.size() << " rules\n");
std::unique_ptr<GIMatchTree> Tree;
{
NamedRegionTimer T("Optimize", "Time spent optimizing the combiner",
"Code Generation", "Time spent generating code",
TimeRegions);
GIMatchTreeBuilder TreeBuilder(0);
for (const auto &Rule : Rules) {
bool HadARoot = false;
for (const auto &Root : enumerate(Rule->getMatchDag().roots())) {
TreeBuilder.addLeaf(Rule->getName(), Root.index(), Rule->getMatchDag(),
Rule.get());
HadARoot = true;
}
if (!HadARoot)
PrintFatalError(Rule->getDef().getLoc(), "All rules must have a root");
}
Tree = TreeBuilder.run();
}
if (StopAfterBuild) {
Tree->writeDOTGraph(outs());
PrintNote(Combiner->getLoc(),
"Terminating due to -gicombiner-stop-after-build");
return;
}
NamedRegionTimer T("Emit", "Time spent emitting the combiner",
"Code Generation", "Time spent generating code",
TimeRegions);
OS << "#ifdef " << Name.upper() << "_GENCOMBINERHELPER_DEPS\n"
<< "#include \"llvm/ADT/SparseBitVector.h\"\n"
<< "namespace llvm {\n"
<< "extern cl::OptionCategory GICombinerOptionCategory;\n"
<< "} // end namespace llvm\n"
<< "#endif // ifdef " << Name.upper() << "_GENCOMBINERHELPER_DEPS\n\n";
OS << "#ifdef " << Name.upper() << "_GENCOMBINERHELPER_H\n"
<< "class " << getClassName() << "RuleConfig {\n"
<< " SparseBitVector<> DisabledRules;\n"
<< "\n"
<< "public:\n"
<< " bool parseCommandLineOption();\n"
<< " bool isRuleDisabled(unsigned ID) const;\n"
<< " bool setRuleEnabled(StringRef RuleIdentifier);\n"
<< " bool setRuleDisabled(StringRef RuleIdentifier);\n"
<< "\n"
<< "};\n"
<< "\n"
<< "class " << getClassName();
StringRef StateClass = Combiner->getValueAsString("StateClass");
if (!StateClass.empty())
OS << " : public " << StateClass;
OS << " {\n"
<< " const " << getClassName() << "RuleConfig *RuleConfig;\n"
<< "\n"
<< "public:\n"
<< " template<typename ... Args>" << getClassName() << "(const "
<< getClassName() << "RuleConfig &RuleConfig, Args &&... args) : ";
if (!StateClass.empty())
OS << StateClass << "(std::forward<Args>(args)...), ";
OS << "RuleConfig(&RuleConfig) {}\n"
<< "\n"
<< " bool tryCombineAll(\n"
<< " GISelChangeObserver &Observer,\n"
<< " MachineInstr &MI,\n"
<< " MachineIRBuilder &B";
emitAdditionalHelperMethodArguments(OS, Combiner);
OS << ") const;\n";
OS << "};\n\n";
emitNameMatcher(OS);
OS << "static Optional<std::pair<uint64_t, uint64_t>> "
"getRuleRangeForIdentifier(StringRef RuleIdentifier) {\n"
<< " std::pair<StringRef, StringRef> RangePair = "
"RuleIdentifier.split('-');\n"
<< " if (!RangePair.second.empty()) {\n"
<< " const auto First = "
"getRuleIdxForIdentifier(RangePair.first);\n"
<< " const auto Last = "
"getRuleIdxForIdentifier(RangePair.second);\n"
<< " if (!First.hasValue() || !Last.hasValue())\n"
<< " return None;\n"
<< " if (First >= Last)\n"
<< " report_fatal_error(\"Beginning of range should be before "
"end of range\");\n"
<< " return {{ *First, *Last + 1 }};\n"
<< " } else if (RangePair.first == \"*\") {\n"
<< " return {{ 0, " << Rules.size() << " }};\n"
<< " } else {\n"
<< " const auto I = getRuleIdxForIdentifier(RangePair.first);\n"
<< " if (!I.hasValue())\n"
<< " return None;\n"
<< " return {{*I, *I + 1}};\n"
<< " }\n"
<< " return None;\n"
<< "}\n\n";
for (bool Enabled : {true, false}) {
OS << "bool " << getClassName() << "RuleConfig::setRule"
<< (Enabled ? "Enabled" : "Disabled") << "(StringRef RuleIdentifier) {\n"
<< " auto MaybeRange = getRuleRangeForIdentifier(RuleIdentifier);\n"
<< " if(!MaybeRange.hasValue())\n"
<< " return false;\n"
<< " for (auto I = MaybeRange->first; I < MaybeRange->second; ++I)\n"
<< " DisabledRules." << (Enabled ? "reset" : "set") << "(I);\n"
<< " return true;\n"
<< "}\n\n";
}
OS << "bool " << getClassName()
<< "RuleConfig::isRuleDisabled(unsigned RuleID) const {\n"
<< " return DisabledRules.test(RuleID);\n"
<< "}\n";
OS << "#endif // ifdef " << Name.upper() << "_GENCOMBINERHELPER_H\n\n";
OS << "#ifdef " << Name.upper() << "_GENCOMBINERHELPER_CPP\n"
<< "\n"
<< "std::vector<std::string> " << Name << "Option;\n"
<< "cl::list<std::string> " << Name << "DisableOption(\n"
<< " \"" << Name.lower() << "-disable-rule\",\n"
<< " cl::desc(\"Disable one or more combiner rules temporarily in "
<< "the " << Name << " pass\"),\n"
<< " cl::CommaSeparated,\n"
<< " cl::Hidden,\n"
<< " cl::cat(GICombinerOptionCategory),\n"
<< " cl::callback([](const std::string &Str) {\n"
<< " " << Name << "Option.push_back(Str);\n"
<< " }));\n"
<< "cl::list<std::string> " << Name << "OnlyEnableOption(\n"
<< " \"" << Name.lower() << "-only-enable-rule\",\n"
<< " cl::desc(\"Disable all rules in the " << Name
<< " pass then re-enable the specified ones\"),\n"
<< " cl::Hidden,\n"
<< " cl::cat(GICombinerOptionCategory),\n"
<< " cl::callback([](const std::string &CommaSeparatedArg) {\n"
<< " StringRef Str = CommaSeparatedArg;\n"
<< " " << Name << "Option.push_back(\"*\");\n"
<< " do {\n"
<< " auto X = Str.split(\",\");\n"
<< " " << Name << "Option.push_back((\"!\" + X.first).str());\n"
<< " Str = X.second;\n"
<< " } while (!Str.empty());\n"
<< " }));\n"
<< "\n"
<< "bool " << getClassName() << "RuleConfig::parseCommandLineOption() {\n"
<< " for (StringRef Identifier : " << Name << "Option) {\n"
<< " bool Enabled = Identifier.consume_front(\"!\");\n"
<< " if (Enabled && !setRuleEnabled(Identifier))\n"
<< " return false;\n"
<< " if (!Enabled && !setRuleDisabled(Identifier))\n"
<< " return false;\n"
<< " }\n"
<< " return true;\n"
<< "}\n\n";
OS << "bool " << getClassName() << "::tryCombineAll(\n"
<< " GISelChangeObserver &Observer,\n"
<< " MachineInstr &MI,\n"
<< " MachineIRBuilder &B";
emitAdditionalHelperMethodArguments(OS, Combiner);
OS << ") const {\n"
<< " MachineBasicBlock *MBB = MI.getParent();\n"
<< " MachineFunction *MF = MBB->getParent();\n"
<< " MachineRegisterInfo &MRI = MF->getRegInfo();\n"
<< " SmallVector<MachineInstr *, 8> MIs = { &MI };\n\n"
<< " (void)MBB; (void)MF; (void)MRI; (void)RuleConfig;\n\n";
OS << " // Match data\n";
for (const auto &Rule : Rules)
for (const auto &I : Rule->matchdata_decls())
OS << " " << I.getType() << " " << I.getVariableName() << ";\n";
OS << "\n";
OS << " int Partition = -1;\n";
generateCodeForTree(OS, *Tree, " ");
OS << "\n return false;\n"
<< "}\n"
<< "#endif // ifdef " << Name.upper() << "_GENCOMBINERHELPER_CPP\n";
}
} // end anonymous namespace
//===----------------------------------------------------------------------===//
namespace llvm {
void EmitGICombiner(RecordKeeper &RK, raw_ostream &OS) {
CodeGenTarget Target(RK);
emitSourceFileHeader("Global Combiner", OS);
if (SelectedCombiners.empty())
PrintFatalError("No combiners selected with -combiners");
for (const auto &Combiner : SelectedCombiners) {
Record *CombinerDef = RK.getDef(Combiner);
if (!CombinerDef)
PrintFatalError("Could not find " + Combiner);
GICombinerEmitter(RK, Target, Combiner, CombinerDef).run(OS);
}
NumPatternTotalStatistic = NumPatternTotal;
}
} // namespace llvm
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