[llvm] [TableGen] Introduce MatcherList to manage a linked list of Matchers. NFC (PR #177875)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu` running on `sie-linux-worker3` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/31625

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
...
8.592 [1693/34/87] Building AArch64GenPostLegalizeGICombiner.inc...
8.720 [1692/34/88] Building AArch64GenAsmWriter1.inc...
8.748 [1691/34/89] Building AArch64GenRegisterBank.inc...
8.815 [1690/34/90] Building AArch64GenAsmWriter.inc...
8.966 [1689/34/91] Building AArch64GenSystemOperands.inc...
9.192 [1688/34/92] Building R600GenAsmWriter.inc...
9.371 [1687/34/93] Building R600GenCallingConv.inc...
9.409 [1686/34/94] Building AArch64GenAsmMatcher.inc...
9.522 [1685/34/95] Building R600GenSubtargetInfo.inc...
9.625 [1684/34/96] Building R600GenDAGISel.inc...
FAILED: lib/Target/AMDGPU/R600GenDAGISel.inc /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/AMDGPU/R600GenDAGISel.inc 
cd /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/AMDGPU && /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen -gen-dag-isel -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/AMDGPU -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/include -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/include -I /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target -omit-comments /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/R600.td --write-if-changed -o R600GenDAGISel.inc -d R600GenDAGISel.inc.d && /usr/bin/cmake/bin/cmake -E cmake_transform_depfile Ninja gccdepfile /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/AMDGPU /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/AMDGPU /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/AMDGPU/R600GenDAGISel.inc.d /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/CMakeFiles/d/db6744c91c35d060b619fee256e317aa5670a6341086552fb40a50a090cb3c5d.d
llvm-tblgen: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp:391: unsigned int {anonymous}::MatcherTableEmitter::SizeMatcher(llvm::Matcher*, llvm::raw_ostream&): Assertion `ChildSize != 0 && "Matcher cannot have child of size 0"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0.	Program arguments: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen -gen-dag-isel -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/AMDGPU -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/include -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/include -I /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target -omit-comments /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/AMDGPU/R600.td --write-if-changed -o R600GenDAGISel.inc -d R600GenDAGISel.inc.d
 #0 0x0000556328905d7f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen+0x3a1d7f)
 #1 0x0000556328902d14 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #2 0x00007f7c93aa7420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #3 0x00007f7c9359200b raise /build/glibc-B3wQXB/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
 #4 0x00007f7c93571859 abort /build/glibc-B3wQXB/glibc-2.31/stdlib/abort.c:81:7
 #5 0x00007f7c93571729 get_sysdep_segment_value /build/glibc-B3wQXB/glibc-2.31/intl/loadmsgcat.c:509:8
 #6 0x00007f7c93571729 _nl_load_domain /build/glibc-B3wQXB/glibc-2.31/intl/loadmsgcat.c:970:34
 #7 0x00007f7c93582fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x000055632875ee51 (anonymous namespace)::MatcherTableEmitter::SizeMatcher(llvm::Matcher*, llvm::raw_ostream&) DAGISelMatcherEmitter.cpp:0:0
 #9 0x00005563287638d7 llvm::EmitMatcherTable(llvm::MatcherList&, llvm::CodeGenDAGPatterns const&, llvm::raw_ostream&) (/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen+0x1ff8d7)
#10 0x0000556328748c38 llvm::TableGen::Emitter::OptClass<(anonymous namespace)::DAGISelEmitter>::run(llvm::StringRef, llvm::RecordKeeper const&) DAGISelEmitter.cpp:0:0
#11 0x0000556328941a11 llvm::TableGen::Emitter::ApplyCallback(llvm::RecordKeeper const&, llvm::TableGenOutputFiles&, llvm::StringRef) (/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen+0x3dda11)
#12 0x00005563289105fb llvm::TableGenMain(char const*, llvm::function_ref<bool (llvm::TableGenOutputFiles&, llvm::RecordKeeper const&)>) (/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen+0x3ac5fb)
#13 0x00005563285d1c05 tblgen_main(int, char**) (/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen+0x6dc05)
#14 0x00007f7c93573083 __libc_start_main /build/glibc-B3wQXB/glibc-2.31/csu/../csu/libc-start.c:342:3
#15 0x00005563285842ce _start (/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen+0x202ce)
Aborted (core dumped)
9.662 [1684/33/97] Building R600GenDFAPacketizer.inc...
10.152 [1684/32/98] Building R600GenInstrInfo.inc...
10.184 [1681/31/99] Building HexagonGenDisassemblerTables.inc...
10.388 [1681/30/100] Building HexagonGenDFAPacketizer.inc...
10.456 [1681/29/101] Building ARMGenAsmWriter.inc...
10.586 [1681/28/102] Building ARMGenAsmMatcher.inc...
10.602 [1681/27/103] Building ARMGenCallingConv.inc...
10.741 [1681/26/104] Building AArch64GenFastISel.inc...
10.829 [1681/25/105] Building ARMGenDisassemblerTables.inc...
11.909 [1681/24/106] Building ARMGenDAGISel.inc...
FAILED: lib/Target/ARM/ARMGenDAGISel.inc /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/ARM/ARMGenDAGISel.inc 
cd /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/ARM && /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen -gen-dag-isel -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/ARM -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/include -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/include -I /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target -omit-comments /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/ARM/ARM.td --write-if-changed -o ARMGenDAGISel.inc -d ARMGenDAGISel.inc.d && /usr/bin/cmake/bin/cmake -E cmake_transform_depfile Ninja gccdepfile /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/ARM /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/ARM /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/ARM/ARMGenDAGISel.inc.d /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/CMakeFiles/d/0b78c933fc13a3acd976dd266c0b091d27bee2a017cc34380d2b3cac30259b87.d
llvm-tblgen: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/include/llvm/Support/Casting.h:109: static bool llvm::isa_impl_cl<To, const From*>::doit(const From*) [with To = llvm::ScopeMatcher; From = llvm::Matcher]: Assertion `Val && "isa<> used on a null pointer"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0.	Program arguments: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/llvm-tblgen -gen-dag-isel -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/ARM -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/include -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/include -I /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target -omit-comments /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/ARM/ARM.td --write-if-changed -o ARMGenDAGISel.inc -d ARMGenDAGISel.inc.d

```

</details>

https://github.com/llvm/llvm-project/pull/177875