[clang] [flang] [llvm] [mlir] [polly] [CMake][LLVM] Add PCH infrastructure and LLVMSupport PCH (PR #176420)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-aarch64-darwin` running on `doug-worker-4` while building `flang,llvm,polly` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/36885

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang Tools :: clang-tidy/infrastructure/custom-query-check.cpp' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 5
sed -e "s:INPUT_DIR:/Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/Inputs/custom-query-check:g" -e "s:OUT_DIR:/Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp:g" -e "s:MAIN_FILE:/Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/custom-query-check.cpp:g" /Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/Inputs/custom-query-check/vfsoverlay.yaml > /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp.yaml
# executed command: sed -e s:INPUT_DIR:/Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/Inputs/custom-query-check:g -e s:OUT_DIR:/Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp:g -e s:MAIN_FILE:/Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/custom-query-check.cpp:g /Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/Inputs/custom-query-check/vfsoverlay.yaml
# note: command had no output on stdout or stderr
# RUN: at line 6
clang-tidy --experimental-custom-checks /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp/main.cpp -checks='-*,custom-*' -vfsoverlay /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp.yaml | FileCheck /Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/custom-query-check.cpp --check-prefix=CHECK-SAME-DIR
# executed command: clang-tidy --experimental-custom-checks /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp/main.cpp '-checks=-*,custom-*' -vfsoverlay /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp.yaml
# .---command stderr------------
# | 1 error generated.
# | Error while processing /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/tools/extra/test/clang-tidy/infrastructure/Output/custom-query-check.cpp.tmp/main.cpp.
# | Found compiler error(s).
# `-----------------------------
# error: command failed with exit status: 1
# executed command: FileCheck /Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/custom-query-check.cpp --check-prefix=CHECK-SAME-DIR
# .---command stderr------------
# | /Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/custom-query-check.cpp:16:20: error: CHECK-SAME-DIR: expected string not found in input
# | // CHECK-SAME-DIR: [[@LINE-1]]:1: warning: use 'int' instead of 'long' [custom-avoid-long-type]
# |                    ^
# | <stdin>:1:1: note: scanning from here
# | error: PCH file '/Users/buildbot/buildbot-root/aarch64-darwin/build/lib/Support/CMakeFiles/LLVMSupport.dir/cmake_pch_arm64.hxx.pch' uses an older format that is no longer supported [clang-diagnostic-error]
# | ^
# | <stdin>:1:1: note: with "@LINE-1" equal to "15"
# | error: PCH file '/Users/buildbot/buildbot-root/aarch64-darwin/build/lib/Support/CMakeFiles/LLVMSupport.dir/cmake_pch_arm64.hxx.pch' uses an older format that is no longer supported [clang-diagnostic-error]
# | ^
# | 
# | Input file: <stdin>
# | Check file: /Users/buildbot/buildbot-root/llvm-project/clang-tools-extra/test/clang-tidy/infrastructure/custom-query-check.cpp
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             1: error: PCH file '/Users/buildbot/buildbot-root/aarch64-darwin/build/lib/Support/CMakeFiles/LLVMSupport.dir/cmake_pch_arm64.hxx.pch' uses an older format that is no longer supported [clang-diagnostic-error] 
# | check:16'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# | check:16'1                                                                                                                                                                                                                    with "@LINE-1" equal to "15"
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/176420