diff --git a/llvm/include/llvm/ADT/CombinationGenerator.h b/llvm/include/llvm/ADT/CombinationGenerator.h new file mode 100644 --- /dev/null +++ b/llvm/include/llvm/ADT/CombinationGenerator.h @@ -0,0 +1,148 @@ +//===-- llvm/ADT/CombinationGenerator.h ------------------------*- C++ -*--===// +// +// 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 +/// Combination generator. +/// +/// Example: given input {{0, 1}, {2}, {3, 4}} it will produce the following +/// combinations: {0, 2, 3}, {0, 2, 4}, {1, 2, 3}, {1, 2, 4}. +/// +/// It is useful to think of input as vector-of-vectors, where the +/// outer vector is the variable space, and inner vector is choice space. +/// The number of choices for each variable can be different. +/// +/// As for implementation, it is useful to think of this as a weird number, +/// where each digit (==variable) may have different base (==number of choices). +/// Thus modelling of 'produce next combination' is exactly analogous to the +/// incrementing of an number - increment lowest digit (pick next choice for the +/// variable), and if it wrapped to the beginning then increment next digit. +/// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ADT_COMBINATIONGENERATOR_H +#define LLVM_ADT_COMBINATIONGENERATOR_H + +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallVector.h" +#include +#include + +namespace llvm { + +template +class CombinationGenerator { + template struct WrappingIterator { + using value_type = T; + + const ArrayRef Range; + typename decltype(Range)::const_iterator Position; + + // Rewind the tape, placing the position to again point at the beginning. + void rewind() { Position = Range.begin(); } + + // Advance position forward, possibly wrapping to the beginning. + // Returns whether the wrap happened. + bool advance() { + ++Position; + bool Wrapped = Position == Range.end(); + if (Wrapped) + rewind(); + return Wrapped; + } + + // Get the value at which we are currently pointing. + const value_type &operator*() const { return *Position; } + + WrappingIterator(ArrayRef Range_) : Range(Range_) { + assert(!Range.empty() && "The range must not be empty."); + rewind(); + } + }; + + const ArrayRef VariablesChoices; + + void performGeneration( + const function_ref)> Callback) const { + SmallVector, variable_smallsize> + VariablesState; + + // 'increment' of the the whole VariablesState is defined identically to the + // increment of a number: starting from the least significant element, + // increment it, and if it wrapped, then propagate that carry by also + // incrementing next (more significant) element. + auto IncrementState = + [](MutableArrayRef> VariablesState) + -> bool { + for (WrappingIterator &Variable : + llvm::reverse(VariablesState)) { + bool Wrapped = Variable.advance(); + if (!Wrapped) + return false; // There you go, next combination is ready. + // We have carry - increment more significant variable next.. + } + return true; // MSB variable wrapped, no more unique combinations. + }; + + // Initialize the per-variable state to refer to the possible choices for + // that variable. + VariablesState.reserve(VariablesChoices.size()); + for (ArrayRef VC : VariablesChoices) + VariablesState.emplace_back(VC); + + // Temporary buffer to store each combination before performing Callback. + SmallVector CurrentCombination; + CurrentCombination.resize(VariablesState.size()); + + while (true) { + // Gather the currently-selected variable choices into a vector. + for (auto I : llvm::zip(VariablesState, CurrentCombination)) + std::get<1>(I) = *std::get<0>(I); + // And pass the new combination into callback, as intended. + if (/*Abort=*/Callback(CurrentCombination)) + return; + // And tick the state to next combination, which will be unique. + if (IncrementState(VariablesState)) + return; // All combinations produced. + } + }; + +public: + CombinationGenerator(ArrayRef VariablesChoices_) + : VariablesChoices(VariablesChoices_) { +#ifndef NDEBUG + assert(!VariablesChoices.empty() && "There should be some variables."); + llvm::for_each(VariablesChoices, [](ArrayRef VariableChoices) { + assert(!VariableChoices.empty() && + "There must always be some choice, at least a placeholder one."); + }); +#endif + } + + // How many combinations can we produce, max? + // This is at most how many times the callback will be called. + size_t numCombinations() const { + size_t NumVariants = 1; + for (ArrayRef VariableChoices : VariablesChoices) + NumVariants *= VariableChoices.size(); + assert(NumVariants >= 1 && + "We should always end up producing at least one combination"); + return NumVariants; + } + + // Actually perform exhaustive combination generation. + // Each result will be passed into the callback. + void generate(const function_ref)> Callback) { + performGeneration(Callback); + } +}; + +} // namespace llvm + +#endif diff --git a/llvm/tools/llvm-exegesis/lib/SnippetGenerator.h b/llvm/tools/llvm-exegesis/lib/SnippetGenerator.h --- a/llvm/tools/llvm-exegesis/lib/SnippetGenerator.h +++ b/llvm/tools/llvm-exegesis/lib/SnippetGenerator.h @@ -21,6 +21,7 @@ #include "LlvmState.h" #include "MCInstrDescView.h" #include "RegisterAliasing.h" +#include "llvm/ADT/CombinationGenerator.h" #include "llvm/MC/MCInst.h" #include "llvm/Support/Error.h" #include @@ -102,128 +103,6 @@ const BitVector &ForbiddenRegs, InstructionTemplate &IT); -// Combination generator. -// -// Example: given input {{0, 1}, {2}, {3, 4}} it will produce the following -// combinations: {0, 2, 3}, {0, 2, 4}, {1, 2, 3}, {1, 2, 4}. -// -// It is important to think of input as vector-of-vectors, where the -// outer vector is the variable space, and inner vector is choice space. -// The number of choices for each variable can be different. -// -// As for implementation, it is useful to think of this as a weird number, -// where each digit (==variable) may have different base (==number of choices). -// Thus modelling of 'produce next combination' is exactly analogous to the -// incrementing of an number - increment lowest digit (pick next choice for the -// variable), and if it wrapped to the beginning then increment next digit. -template -class CombinationGenerator { - template struct WrappingIterator { - using value_type = T; - - const ArrayRef Range; - typename decltype(Range)::const_iterator Position; - - // Rewind the tape, placing the position to again point at the beginning. - void rewind() { Position = Range.begin(); } - - // Advance position forward, possibly wrapping to the beginning. - // Returns whether the wrap happened. - bool operator++() { - ++Position; - bool Wrapped = Position == Range.end(); - if (Wrapped) - rewind(); - return Wrapped; - } - - // Get the value at which we are currently pointing. - operator const value_type &() const { return *Position; } - - WrappingIterator(ArrayRef Range_) : Range(Range_) { - assert(!Range.empty() && "The range must not be empty."); - rewind(); - } - }; - - const ArrayRef VariablesChoices; - - void performGeneration( - const function_ref)> Callback) const { - SmallVector, variable_smallsize> - VariablesState; - - // 'increment' of the the whole VariablesState is defined identically to the - // increment of a number: starting from the least significant element, - // increment it, and if it wrapped, then propagate that carry by also - // incrementing next (more significant) element. - auto IncrementState = - [](MutableArrayRef> VariablesState) - -> bool { - for (WrappingIterator &Variable : - llvm::reverse(VariablesState)) { - bool Wrapped = ++Variable; - if (!Wrapped) - return false; // There you go, next combination is ready. - // We have carry - increment more significant variable next.. - } - return true; // MSB variable wrapped, no more unique combinations. - }; - - // Initialize the per-variable state to refer to the possible choices for - // that variable. - VariablesState.reserve(VariablesChoices.size()); - for (ArrayRef VC : VariablesChoices) - VariablesState.emplace_back(VC); - - // Temporary buffer to store each combination before performing Callback. - SmallVector CurrentCombination; - CurrentCombination.resize(VariablesState.size()); - - while (true) { - // Gather the currently-selected variable choices into a vector. - for (auto I : llvm::zip(VariablesState, CurrentCombination)) - std::get<1>(I) = std::get<0>(I); - // And pass the new combination into callback, as intended. - if (/*Abort=*/Callback(CurrentCombination)) - return; - // And tick the state to next combination, which will be unique. - if (IncrementState(VariablesState)) - return; // All combinations produced. - } - }; - -public: - CombinationGenerator(ArrayRef VariablesChoices_) - : VariablesChoices(VariablesChoices_) { -#ifndef NDEBUG - assert(!VariablesChoices.empty() && "There should be some variables."); - llvm::for_each(VariablesChoices, [](ArrayRef VariableChoices) { - assert(!VariableChoices.empty() && - "There must always be some choice, at least a placeholder one."); - }); -#endif - } - - // How many combinations can we produce, max? - // This is at most how many times the callback will be called. - size_t numCombinations() const { - size_t NumVariants = 1; - for (ArrayRef VariableChoices : VariablesChoices) - NumVariants *= VariableChoices.size(); - assert(NumVariants >= 1 && - "We should always end up producing at least one combination"); - return NumVariants; - } - - // Actually perform exhaustive combination generation. - // Each result will be passed into the callback. - void generate(const function_ref)> Callback) { - performGeneration(Callback); - } -}; - } // namespace exegesis } // namespace llvm diff --git a/llvm/unittests/ADT/CMakeLists.txt b/llvm/unittests/ADT/CMakeLists.txt --- a/llvm/unittests/ADT/CMakeLists.txt +++ b/llvm/unittests/ADT/CMakeLists.txt @@ -15,6 +15,7 @@ BreadthFirstIteratorTest.cpp BumpPtrListTest.cpp CoalescingBitVectorTest.cpp + CombinationGeneratorTest.cpp DAGDeltaAlgorithmTest.cpp DeltaAlgorithmTest.cpp DenseMapTest.cpp diff --git a/llvm/unittests/tools/llvm-exegesis/SnippetGeneratorTest.cpp b/llvm/unittests/ADT/CombinationGeneratorTest.cpp rename from llvm/unittests/tools/llvm-exegesis/SnippetGeneratorTest.cpp rename to llvm/unittests/ADT/CombinationGeneratorTest.cpp --- a/llvm/unittests/tools/llvm-exegesis/SnippetGeneratorTest.cpp +++ b/llvm/unittests/ADT/CombinationGeneratorTest.cpp @@ -1,4 +1,4 @@ -//===-- SnippetGeneratorTest.cpp --------------------------------*- C++ -*-===// +//===- llvm/unittest/ADT/CombinationGeneratorTest.cpp ---------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. @@ -6,13 +6,21 @@ // //===----------------------------------------------------------------------===// -#include "SnippetGenerator.h" +#include "llvm/ADT/CombinationGenerator.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/STLForwardCompat.h" +#include "llvm/ADT/iterator_range.h" +#include "llvm/Support/ErrorHandling.h" #include "gmock/gmock.h" #include "gtest/gtest.h" -#include +#include +#include +#include +#include +#include -namespace llvm { -namespace exegesis { +using namespace llvm; namespace { @@ -170,6 +178,4 @@ ASSERT_THAT(Variants, ::testing::ContainerEq(ExpectedVariants)); } -} // namespace -} // namespace exegesis -} // namespace llvm +} // end anonymous namespace diff --git a/llvm/unittests/tools/llvm-exegesis/CMakeLists.txt b/llvm/unittests/tools/llvm-exegesis/CMakeLists.txt --- a/llvm/unittests/tools/llvm-exegesis/CMakeLists.txt +++ b/llvm/unittests/tools/llvm-exegesis/CMakeLists.txt @@ -15,7 +15,6 @@ ClusteringTest.cpp PerfHelperTest.cpp RegisterValueTest.cpp - SnippetGeneratorTest.cpp ) set(exegesis_link_libraries LLVMExegesis)