llvm社区BOLT aarch64插桩功能回合17.0.6

## 分析
llvm社区llvmorg-18.1.0版本是社区第一个支持aarch插桩功能的版本，以下内容基于该版本给出分析。
梳理llvmorg-17.0.6至llvmorg-18.1.0之间和插桩有关的commit如下：

| index | commit | commit time | type | pick | info |
| ----- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------- | ---- | ---- | ------------------------------------------------------------------------------- |
| 1 | [[BOLT] Fix instrumenting conditional tail calls](https://github.com/llvm/llvm-project/commit/70e76e0982a9dc27b8c252353609e3a778c2bec0) 70e76e0982a9dc27b8c252353609e3a778c2bec0 | 2023.8.1 | 功能修复 | yes | 插桩功能修复（尾调用） |
| 2 | [[BOLT] fix the endless loop of --iterative-guess](https://github.com/llvm/llvm-project/commit/892305adb116552caf826557f9786e5773e27e37) 892305adb116552caf826557f9786e5773e27e37 | 2023.8.4 | 功能修复 | yes | 插桩参数--iterative-guess功能修复 |
| 3 | [[BOLT] Consider Code Fragments during regreassign](https://github.com/llvm/llvm-project/commit/a37e8a4bdc4feab14d44eb043a2dfda0c64335ba) a37e8a4bdc4feab14d44eb043a2dfda0c64335ba | 2023.8.14 | 功能修复 | | 仅 --reg-reassign且PGO场景有问题，和插桩无关 |
| 4 | [[BOLT][Instrumentation] Keep profile open in WatchProcess](https://github.com/llvm/llvm-project/commit/a799298152e3ef08b4919cdaac7a614f7cca9bc6) a799298152e3ef08b4919cdaac7a614f7cca9bc6 | 2023.8.24 | 功能 | | 插桩参数--instrumentation-sleep-time and instrumentation-wait-forks优化 已包含在17.0.6 |
| 5 | [[BOLT][Instrumentation] Fix indirect call profile in PIE](https://github.com/llvm/llvm-project/commit/a86dd9ae60662cfe9f9fb709a33c71d6fec66dfb) a86dd9ae60662cfe9f9fb709a33c71d6fec66dfb | 2023.8.24 | 功能修复 | | 插桩功能修复（PIE场景） 已包含在17.0.6 |
| 6 | [[BOLT][Instrumentation] Add test for append-pid option](https://github.com/llvm/llvm-project/commit/dfc759929644ed1ea3224ab30e1086f7acc60da6) dfc759929644ed1ea3224ab30e1086f7acc60da6 | 2023.8.24 | 测试 | | 上一条的测试 已包含在17.0.6 |
| 7 | [[BOLT] Fix trap value for non-X86](https://github.com/llvm/llvm-project/commit/28fd2ca142462c3ed9a9dca43a3dfd98edbd4151) 28fd2ca142462c3ed9a9dca43a3dfd98edbd4151 | 2023.8.24 | 功能修复 | yes | 功能修复 |
| 8 | [[BOLT][Instrumentation] Initial instrumentation support for AArch64](https://github.com/llvm/llvm-project/commit/6e4c230525fb66ddf4310c53bb621b5ccc579444) 6e4c230525fb66ddf4310c53bb621b5ccc579444 | 2023.8.25 | 功能 | yes | aarch64插桩核心功能 |
| 9 | [[BOLT][Instrumentation] Add support for MacOS counters](https://github.com/llvm/llvm-project/commit/70405a0bf70fe1b16691fc24bae65eb0c9ff0151) 70405a0bf70fe1b16691fc24bae65eb0c9ff0151 | 2023.8.25 | 功能 | yes | MacOS适配（实际aarch64下就需要） |
| 10 | [[BOLT][Instrumentation] AArch64 instrumentation support in runtime](https://github.com/llvm/llvm-project/commit/87e9c42495aa4d290b04fa2866ec0e627a54842a) 87e9c42495aa4d290b04fa2866ec0e627a54842a | 2023.8.25 | 功能 | yes | aarch64插桩runtime适配 |
| 11 | [[BOLT][Instrumentation][test] Fix tests](https://github.com/llvm/llvm-project/commit/83cb541f806dc7745361ba80ddfe4d0a000bd366) 83cb541f806dc7745361ba80ddfe4d0a000bd366 | 2023.8.25 | 测试 | yes | aarch64插桩配套测试 |
| 12 | [[BOLT][test] Enable exceptions_split tests for AArch64](https://github.com/llvm/llvm-project/commit/777e268b8168b326db54ecacb62733ee926bb781) 777e268b8168b326db54ecacb62733ee926bb781 | 2023.9.1 | 测试 | yes | [BOLT] Fix trap value for non-X86的测试 |
| 13 | [[BOLT][test] Fix cross-compilation tests after D151920](https://github.com/llvm/llvm-project/commit/6678f602c243fe8a9c9db9d02b162f02ecec5173) 6678f602c243fe8a9c9db9d02b162f02ecec5173 | 2023.9.8 | 功能修复 | yes | 交叉编译修复 |
| 14 | [[BOLT] Fix deadloop bug in taildup](https://github.com/llvm/llvm-project/commit/de6a919f77f2a63f9e7f86ec51cf8a508fedf188) de6a919f77f2a63f9e7f86ec51cf8a508fedf188 | 2023.9.15 | 功能修复 | yes | 修复了插桩优化后出现死循环的问题 |
| 15 | [[BOLT][AArch64] Fix instrumentation deadloop](https://github.com/llvm/llvm-project/commit/846eb76761c858cbfc75700bf68445e0e3ade48e) 846eb76761c858cbfc75700bf68445e0e3ade48e | 2023.9.22 | 功能修复 | yes | 插桩功能修复 |
| 16 | [[BOLT] Implement '--assume-abi' option for AArch64](https://github.com/llvm/llvm-project/commit/2d902d0f880498145f70e41a265c1adecb05d089) 2d902d0f880498145f70e41a265c1adecb05d089 | 2023.9.26 | 功能 | yes | 插桩参数--assume-abi功能实现 |

## 验证
插桩版本和优化版本构建打印

```shell
1. 插桩版本构建
[root@DC1-20-001 build]# /data/wrf/rpmbuild/BUILD/llvm-project-17.0.6.src.instrumentation/build/bin/llvm-bolt /home/wrf/install/mysql/bin/mysqld -instrument -o /home/wrf/install/mysql/bin/mysqld.inst -instrumentation-file=/home/wrf/install/mysqld.inst.fdata --instrumentation-wait-forks -instrumentation-sleep-time=2 -instrumentation-no-counters-clear --instrumentation-binpath=/home/wrf/install/mysql/bin/mysqld.inst
BOLT-INFO: Target architecture: aarch64
BOLT-INFO: BOLT version: <unknown>
BOLT-INFO: first alloc address is 0x400000
BOLT-INFO: creating new program header table at address 0x3e00000, offset 0x3a00000
BOLT-WARNING: debug info will be stripped from the binary. Use -update-debug-sections to keep it.
BOLT-INFO: enabling relocation mode
BOLT-INFO: forcing -jump-tables=move for instrumentation
BOLT-INFO: disabling -align-macro-fusion on non-x86 platform
BOLT-INFO: number of removed linker-inserted veneers: 0
BOLT-INFO: 0 out of 60792 functions in the binary (0.0%) have non-empty execution profile
BOLT-INSTRUMENTER: Number of indirect call site descriptors: 32138
BOLT-INSTRUMENTER: Number of indirect call target descriptors: 59690
BOLT-INSTRUMENTER: Number of function descriptors: 59689
BOLT-INSTRUMENTER: Number of branch counters: 510956
BOLT-INSTRUMENTER: Number of ST leaf node counters: 314667
BOLT-INSTRUMENTER: Number of direct call counters: 250716
BOLT-INSTRUMENTER: Total number of counters: 1076339
BOLT-INSTRUMENTER: Total size of counters: 8610712 bytes (static alloc memory)
BOLT-INSTRUMENTER: Total size of string table emitted: 6611882 bytes in file
BOLT-INSTRUMENTER: Total size of descriptors: 59403936 bytes in file
BOLT-INSTRUMENTER: Profile will be saved to file /home/wrf/install/mysqld.inst.fdata
BOLT-INFO: removed 6550 empty blocks
BOLT-INFO: Starting stub-insertion pass
BOLT-INFO: Inserted 2 stubs in the hot area and 0 stubs in the cold area. Shared 0 times, iterated 2 times.
BOLT-INFO: padding code to 0x8400000 to accommodate hot text
BOLT-INFO: output linked against instrumentation runtime library, lib entry point is 0x94771e4
BOLT-INFO: clear procedure is 0x9475ea0
BOLT-INFO: setting _end to 0x956e774
BOLT-INFO: setting _end to 0x956e774
BOLT-INFO: setting __hot_start to 0x4000000
BOLT-INFO: setting __hot_end to 0x822e380
BOLT-INFO: patched build-id (flipped last bit)

2. 优化版本构建
[root@DC1-20-001 build]# /data/wrf/rpmbuild/BUILD/llvm-project-17.0.6.src.instrumentation/build/bin/llvm-bolt /home/wrf/install/mysql/bin/mysqld -o /home/wrf/install/mysql/bin/mysqld.opt -data=/home/wrf/install/mysqld.inst.fdata --infer-fall-throughs -reorder-blocks=ext-tsp -reorder-functions=hfsort+ -split-functions -split-all-cold -dyno-stats -icf=1 -use-gnu-stack --peepholes=useless-branches --simplify-conditional-tail-calls --simplify-rodata-loads --indirect-call-promotion-use-mispredicts --elim-link-veneers --eliminate-unreachable --fix-block-counts --fix-func-counts --sctc-mode=preserve --align-blocks --cg-use-split-hot-size --tail-duplication=aggressive --iterative-guess --assume-abi
BOLT-INFO: Target architecture: aarch64
BOLT-INFO: BOLT version: <unknown>
BOLT-INFO: first alloc address is 0x400000
BOLT-WARNING: debug info will be stripped from the binary. Use -update-debug-sections to keep it.
BOLT-INFO: enabling relocation mode
BOLT-INFO: disabling -align-macro-fusion on non-x86 platform
BOLT-INFO: pre-processing profile using branch profile reader
BOLT-INFO: number of removed linker-inserted veneers: 0
BOLT-INFO: 9552 out of 60792 functions in the binary (15.7%) have non-empty execution profile
BOLT-INFO: 81 functions with profile could not be optimized
BOLT-INFO: profile for 1 objects was ignored
BOLT-INFO: removed 8021 empty blocks
BOLT-INFO: ICF folded 16161 out of 61560 functions in 7 passes. 0 functions had jump tables.
BOLT-INFO: Removing all identical functions will save 1999.18 KB of code space. Folded functions were called 1091911514 times based on profile.
BOLT-INFO: simplified 0 out of 0 loads from a statically computed address.
BOLT-INFO: dynamic loads simplified: 0
BOLT-INFO: dynamic loads found: 0
BOLT-INFO: basic block reordering modified layout of 4374 functions (45.79% of profiled, 9.63% of total)
BOLT-INFO: 92 Functions were reordered by LoopInversionPass
BOLT-INFO: tail duplication modified 47 (0.10%) functions; duplicated 55 blocks (928 bytes) responsible for 5888932 dynamic executions (0.01% of all block executions)
BOLT-INFO: hfsort+ reduced the number of chains from 7905 to 4529
BOLT-INFO: program-wide dynostats after all optimizations before SCTC and FOP:
BOLT-INFO: Peephole: 0 double jumps patched.
BOLT-INFO: Peephole: 0 tail call traps inserted.
BOLT-INFO: Peephole: 0 useless conditional branches removed.
BOLT-INFO: Starting stub-insertion pass
BOLT-INFO: Inserted 20677 stubs in the hot area and 14824 stubs in the cold area. Shared 0 times, iterated 3 times.
BOLT-INFO: setting _end to 0x5b0be4c
BOLT-INFO: setting _end to 0x5b0be4c
BOLT-INFO: setting __hot_start to 0x3e00000
BOLT-INFO: setting __hot_end to 0x41055a4
BOLT-INFO: patched build-id (flipped last bit)
```

| 测试场景 | 基线 | BOLT采样优化 | BOLT插桩优化 |
| ----------------------------------------- | ---- | -------- | -------- |
| 16C sysbench SELECT测试(tps) 测试前预热一次，60s | 2725 | 3646 | 4123 |

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