[PATCH] D127283: [pseudo] Simplify the glrReduce implementation.
Haojian Wu via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Wed Jun 8 03:11:30 PDT 2022
hokein created this revision.
hokein added a reviewer: sammccall.
Herald added a project: All.
hokein requested review of this revision.
Herald added a subscriber: alextsao1999.
Herald added a project: clang-tools-extra.
glrReduce maintains two priority queues (one for bases, and the other
for Sequence), these queues are in parallel with each other, corresponding to a
single family. They can be folded into one.
This patch removes the bases priority queue, which improves the glrParse by
10%.
ASTReader.cpp: 2.03M/s (before) vs 2.26M/s (after)
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D127283
Files:
clang-tools-extra/pseudo/lib/GLR.cpp
Index: clang-tools-extra/pseudo/lib/GLR.cpp
===================================================================
--- clang-tools-extra/pseudo/lib/GLR.cpp
+++ clang-tools-extra/pseudo/lib/GLR.cpp
@@ -259,18 +259,19 @@
}
};
- // The base nodes are the heads after popping the GSS nodes we are reducing.
- // We don't care which rule yielded each base. If Family.Symbol is S, the
- // base includes an item X := ... • S ... and since the grammar is
- // context-free, *all* parses of S are valid here.
- // FIXME: reuse the queues across calls instead of reallocating.
- KeyedQueue<Family, const GSS::Node *> Bases;
-
// A sequence is the ForestNode payloads of the GSS nodes we are reducing.
// These are the RHS of the rule, the RuleID is stored in the Family.
// They specify a sequence ForestNode we may build (but we dedup first).
using Sequence = llvm::SmallVector<const ForestNode *, Rule::MaxElements>;
- KeyedQueue<Family, Sequence> Sequences;
+ struct SeqNodeSpec {
+ // The base nodes are the heads after popping the GSS nodes we are reducing.
+ // We don't care which rule yielded each base. If Family.Symbol is S, the
+ // base includes an item X := ... • S ... and since the grammar is
+ // context-free, *all* parses of S are valid here.
+ const GSS::Node* Base = nullptr;
+ Sequence Seq;
+ };
+ KeyedQueue<Family, SeqNodeSpec> Sequences;
Sequence TempSequence;
// Pop walks up the parent chain(s) for a reduction from Head by to Rule.
@@ -283,9 +284,8 @@
auto DFS = [&](const GSS::Node *N, unsigned I, auto &DFS) {
if (I == Rule.Size) {
F.Start = TempSequence.front()->startTokenIndex();
- Bases.emplace(F, N);
LLVM_DEBUG(llvm::dbgs() << " --> base at S" << N->State << "\n");
- Sequences.emplace(F, TempSequence);
+ Sequences.emplace(F, SeqNodeSpec{N, TempSequence});
return;
}
TempSequence[Rule.Size - 1 - I] = N->Payload;
@@ -311,20 +311,23 @@
// - process one family at a time, forming a forest node
// - produces new GSS heads which may enable more pops
PopPending();
- while (!Bases.empty()) {
- // We should always have bases and sequences for the same families.
- Family F = Bases.top().first;
- assert(!Sequences.empty());
- assert(Sequences.top().first == F);
+ while (!Sequences.empty()) {
+ Family F = Sequences.top().first;
LLVM_DEBUG(llvm::dbgs() << " Push " << Params.G.symbolName(F.Symbol)
<< " from token " << F.Start << "\n");
- // Grab the sequences for this family.
+ // Grab the sequences and bases for this family.
FamilySequences.clear();
+ FamilyBases.clear();
do {
FamilySequences.emplace_back(Sequences.top().first.Rule,
- Sequences.top().second);
+ Sequences.top().second.Seq);
+ FamilyBases.emplace_back(
+ Params.Table.getGoToState(Sequences.top().second.Base->State,
+ F.Symbol),
+ Sequences.top().second.Base);
+
Sequences.pop();
} while (!Sequences.empty() && Sequences.top().first == F);
// Build a forest node for each unique sequence.
@@ -341,15 +344,7 @@
: &Params.Forest.createAmbiguous(F.Symbol, SequenceNodes);
LLVM_DEBUG(llvm::dbgs() << " --> " << Parsed->dump(Params.G) << "\n");
- // Grab the bases for this family.
- // As well as deduplicating them, we'll group by the goto state.
- FamilyBases.clear();
- do {
- FamilyBases.emplace_back(
- Params.Table.getGoToState(Bases.top().second->State, F.Symbol),
- Bases.top().second);
- Bases.pop();
- } while (!Bases.empty() && Bases.top().first == F);
+ // Bases for this family, deduplicate them, and group by the goTo State.
sortAndUnique(FamilyBases);
// Create a GSS node for each unique goto state.
llvm::ArrayRef<decltype(FamilyBases)::value_type> BasesLeft = FamilyBases;
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