[GHA] Cancel intermediate builds on PRs

[vchuravy]

Summary

Setup GHA to skip runs when subsequent pushes to a PR occur.

[tstellar]

What is the motivation for this change, do you not want GitHub actions to run in your fork of llvm-project?

[vchuravy]

We are starting to use a Github fork to manage our (yet to upstream) patch-set. I am expecting contributors to open PRs to add new patches that we accumulate.
This reduces resource usage when users force-push or add multiple commits to a branch.

[tstellar]

In D111499#3055633, @vchuravy wrote:

We are starting to use a Github fork to manage our (yet to upstream) patch-set. I am expecting contributors to open PRs to add new patches that we accumulate.
This reduces resource usage when users force-push or add multiple commits to a branch.

So, you don't mind having the GitHub Actions running in your fork?

[tstellar]

Merged to release/13.x as 449f3049b5075ace277748595a1495bbaa8c8d55.

.github/workflows/clang-tests.yml

 name: Clang Tests
 
 on:
   push:
     branches:
       - 'release/**'
     paths:
       - 'clang/**'
       - 'llvm/**'
       - '.github/workflows/clang-tests.yml'
   pull_request:
     paths:
       - 'clang/**'
       - 'llvm/**'
       - '.github/workflows/clang-tests.yml'
 
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
+
 jobs:
   build_clang:
     name: clang check-all
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         os:

.github/workflows/libclang-abi-tests.yml

 name: libclang ABI Tests
 
 on:
   push:
     branches:
       - 'release/**'
     paths:
       - 'clang/**'
       - '.github/workflows/libclang-abi-tests.yml'
   pull_request:
     paths:
       - 'clang/**'
       - '.github/workflows/libclang-abi-tests.yml'
 
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
+
+
 jobs:
   abi-dump-setup:
     runs-on: ubuntu-latest
     outputs:
       BASELINE_REF: ${{ steps.vars.outputs.BASELINE_REF }}
       ABI_HEADERS: ${{ steps.vars.outputs.ABI_HEADERS }}
       ABI_LIBS: ${{ steps.vars.outputs.ABI_LIBS }}
       BASELINE_VERSION_MAJOR: ${{ steps.vars.outputs.BASELINE_VERSION_MAJOR }}

.github/workflows/libclc-tests.yml

paths:
       - '.github/workflows/libclc-tests.yml'
   pull_request:
     paths:
       - 'clang/**'
       - 'llvm/**'
       - 'libclc/**'
       - '.github/workflows/libclc-tests.yml'
 
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
+
+
 jobs:
   build_libclc:
     name: libclc test
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         os:

.github/workflows/lld-tests.yml

 name: LLD Tests
 
 on:
   push:
     branches:
       - 'release/**'
     paths:
       - 'lld/**'
       - 'llvm/**'
       - '.github/workflows/lld-tests.yml'
   pull_request:
     paths:
       - 'lld/**'
       - 'llvm/**'
       - '.github/workflows/lld-tests.yml'
 
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
+
 jobs:
   build_lld:
     name: lld check-all
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         os:

.github/workflows/lldb-tests.yml

paths:
       - '.github/workflows/lldb-tests.yml'
   pull_request:
     paths:
       - 'clang/**'
       - 'llvm/**'
       - 'lldb/**'
       - '.github/workflows/lldb-tests.yml'
 
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
+
+
 jobs:
   build_lldb:
     name: lldb build
     runs-on: ${{ matrix.os }}
     # Workaround for build faliure on Mac OS X: llvm.org/PR46190, https://github.com/actions/virtual-environments/issues/2274
     env:
       CPLUS_INCLUDE_PATH: /usr/local/opt/llvm/include/c++/v1:/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include
     strategy:

.github/workflows/llvm-tests.yml

 name: LLVM Tests
 
 on:
   push:
     branches:
       - 'release/**'
     paths:
       - 'llvm/**'
       - '.github/workflows/llvm-tests.yml'
   pull_request:
     paths:
       - 'llvm/**'
       - '.github/workflows/llvm-tests.yml'
 
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
+
+
 jobs:
   build_llvm:
     name: llvm check-all
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         os: