110 lines
3.8 KiB
C++
110 lines
3.8 KiB
C++
//===-- SnippetGenerator.h --------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// Defines the abstract SnippetGenerator class for generating code that allows
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/// measuring a certain property of instructions (e.g. latency).
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TOOLS_LLVM_EXEGESIS_SNIPPETGENERATOR_H
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#define LLVM_TOOLS_LLVM_EXEGESIS_SNIPPETGENERATOR_H
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#include "Assembler.h"
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#include "BenchmarkCode.h"
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#include "CodeTemplate.h"
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#include "LlvmState.h"
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#include "MCInstrDescView.h"
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#include "RegisterAliasing.h"
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#include "llvm/ADT/CombinationGenerator.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/Support/Error.h"
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#include <cstdlib>
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#include <memory>
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#include <vector>
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namespace llvm {
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namespace exegesis {
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std::vector<CodeTemplate> getSingleton(CodeTemplate &&CT);
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// Generates code templates that has a self-dependency.
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Expected<std::vector<CodeTemplate>>
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generateSelfAliasingCodeTemplates(InstructionTemplate Variant);
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// Generates code templates without assignment constraints.
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Expected<std::vector<CodeTemplate>>
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generateUnconstrainedCodeTemplates(const InstructionTemplate &Variant,
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StringRef Msg);
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// A class representing failures that happened during Benchmark, they are used
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// to report informations to the user.
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class SnippetGeneratorFailure : public StringError {
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public:
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SnippetGeneratorFailure(const Twine &S);
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};
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// Common code for all benchmark modes.
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class SnippetGenerator {
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public:
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struct Options {
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unsigned MaxConfigsPerOpcode = 1;
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};
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explicit SnippetGenerator(const LLVMState &State, const Options &Opts);
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virtual ~SnippetGenerator();
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// Calls generateCodeTemplate and expands it into one or more BenchmarkCode.
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Error generateConfigurations(const InstructionTemplate &Variant,
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std::vector<BenchmarkCode> &Benchmarks,
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const BitVector &ExtraForbiddenRegs) const;
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// Given a snippet, computes which registers the setup code needs to define.
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std::vector<RegisterValue> computeRegisterInitialValues(
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const std::vector<InstructionTemplate> &Snippet) const;
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protected:
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const LLVMState &State;
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const Options Opts;
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private:
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// API to be implemented by subclasses.
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virtual Expected<std::vector<CodeTemplate>>
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generateCodeTemplates(InstructionTemplate Variant,
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const BitVector &ForbiddenRegisters) const = 0;
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};
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// A global Random Number Generator to randomize configurations.
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// FIXME: Move random number generation into an object and make it seedable for
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// unit tests.
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std::mt19937 &randomGenerator();
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// Picks a random unsigned integer from 0 to Max (inclusive).
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size_t randomIndex(size_t Max);
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// Picks a random bit among the bits set in Vector and returns its index.
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// Precondition: Vector must have at least one bit set.
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size_t randomBit(const BitVector &Vector);
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// Picks a random configuration, then selects a random def and a random use from
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// it and finally set the selected values in the provided InstructionInstances.
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void setRandomAliasing(const AliasingConfigurations &AliasingConfigurations,
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InstructionTemplate &DefIB, InstructionTemplate &UseIB);
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// Assigns a Random Value to all Variables in IT that are still Invalid.
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// Do not use any of the registers in `ForbiddenRegs`.
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Error randomizeUnsetVariables(const LLVMState &State,
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const BitVector &ForbiddenRegs,
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InstructionTemplate &IT);
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} // namespace exegesis
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} // namespace llvm
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#endif // LLVM_TOOLS_LLVM_EXEGESIS_SNIPPETGENERATOR_H
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