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https://github.com/c64scene-ar/llvm-6502.git
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fc1a161d76
Refactor the TableGen'erated fixed length disassemblmer to use a table-driven state machine rather than a massive set of nested switch() statements. As a result, the ARM Disassembler (ARMDisassembler.cpp) builds much more quickly and generates a smaller end result. For a Release+Asserts build on a 16GB 3.4GHz i7 iMac w/ SSD: Time to compile at -O2 (averaged w/ hot caches): Previous: 35.5s New: 8.9s TEXT size: Previous: 447,251 New: 297,661 Builds in 25% of the time previously required and generates code 66% of the size. Execution time of the disassembler is only slightly slower (7% disassembling 10 million ARM instructions, 19.6s vs 21.0s). The new implementation has not yet been tuned, however, so the performance should almost certainly be recoverable should it become a concern. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161888 91177308-0d34-0410-b5e6-96231b3b80d8
33 lines
1.2 KiB
C++
33 lines
1.2 KiB
C++
//===-- llvm/MC/MCFixedLenDisassembler.h - Decoder driver -------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// Fixed length disassembler decoder state machine driver.
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//===----------------------------------------------------------------------===//
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#ifndef MCFIXEDLENDISASSEMBLER_H
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#define MCFIXEDLENDISASSEMBLER_H
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namespace llvm {
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namespace MCD {
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// Disassembler state machine opcodes.
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enum DecoderOps {
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OPC_ExtractField = 1, // OPC_ExtractField(uint8_t Start, uint8_t Len)
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OPC_FilterValue, // OPC_FilterValue(uleb128 Val, uint16_t NumToSkip)
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OPC_CheckField, // OPC_CheckField(uint8_t Start, uint8_t Len,
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// uleb128 Val, uint16_t NumToSkip)
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OPC_CheckPredicate, // OPC_CheckPredicate(uleb128 PIdx, uint16_t NumToSkip)
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OPC_Decode, // OPC_Decode(uleb128 Opcode, uleb128 DIdx)
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OPC_SoftFail, // OPC_SoftFail(uleb128 PMask, uleb128 NMask)
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OPC_Fail // OPC_Fail()
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};
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} // namespace MCDecode
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} // namespace llvm
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#endif
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