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Summary: Currently, we only have nice exploration for LEA instruction, while for the rest, we rely on `randomizeUnsetVariables()` to sometimes generate something interesting. While that works, it isn't very reliable in coverage :) Here, i'm making an assumption that while we may want to explore multi-instruction configs, we are most interested in the characteristics of the main instruction we were asked about. Which we can do, by taking the existing `randomizeMCOperand()`, and turning it on it's head - instead of relying on it to randomly fill one of the interesting values, let's pregenerate all the possible interesting values for the variable, and then generate as much `InstructionTemplate` combinations of these possible values for variables as needed/possible. Of course, that requires invasive changes to no longer pass just the naked `Instruction`, but sometimes partially filled `InstructionTemplate`. As it can be seen from the test, this allows us to explore `X86::OperandType::OPERAND_COND_CODE` for instructions that take such an operand. I'm hoping this will greatly simplify exploration. Reviewers: courbet, gchatelet Reviewed By: gchatelet Subscribers: orodley, mgorny, sdardis, tschuett, jrtc27, atanasyan, mstojanovic, andreadb, RKSimon, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D74156
66 lines
2.2 KiB
C++
66 lines
2.2 KiB
C++
//===-- ParallelSnippetGenerator.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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/// A SnippetGenerator implementation to create parallel instruction snippets.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TOOLS_LLVM_EXEGESIS_PARALLELSNIPPETGENERATOR_H
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#define LLVM_TOOLS_LLVM_EXEGESIS_PARALLELSNIPPETGENERATOR_H
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#include "SnippetGenerator.h"
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namespace llvm {
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namespace exegesis {
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class ParallelSnippetGenerator : public SnippetGenerator {
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public:
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using SnippetGenerator::SnippetGenerator;
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~ParallelSnippetGenerator() override;
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Expected<std::vector<CodeTemplate>>
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generateCodeTemplates(InstructionTemplate Variant,
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const BitVector &ForbiddenRegisters) const override;
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static constexpr const size_t kMinNumDifferentAddresses = 6;
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private:
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// Instantiates memory operands within a snippet.
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// To make computations as parallel as possible, we generate independant
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// memory locations for instructions that load and store. If there are less
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// than kMinNumDifferentAddresses in the original snippet, we duplicate
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// instructions until there are this number of instructions.
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// For example, assuming kMinNumDifferentAddresses=5 and
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// getMaxMemoryAccessSize()=64, if the original snippet is:
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// mov eax, [memory]
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// we might generate:
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// mov eax, [rdi]
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// mov eax, [rdi + 64]
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// mov eax, [rdi + 128]
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// mov eax, [rdi + 192]
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// mov eax, [rdi + 256]
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// If the original snippet is:
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// mov eax, [memory]
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// add eax, [memory]
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// we might generate:
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// mov eax, [rdi]
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// add eax, [rdi + 64]
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// mov eax, [rdi + 128]
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// add eax, [rdi + 192]
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// mov eax, [rdi + 256]
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void instantiateMemoryOperands(
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unsigned ScratchSpaceReg,
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std::vector<InstructionTemplate> &SnippetTemplate) const;
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};
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} // namespace exegesis
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} // namespace llvm
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#endif // LLVM_TOOLS_LLVM_EXEGESIS_PARALLELSNIPPETGENERATOR_H
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