[build] Turn TI_LLVM_15 on by default (taichi-dev#6649)

For taichi devs, if you hit any issues with this option, please turn it
off temporarily and open an issue.

Issue: taichi-dev#6447

### Brief Summary

There're a few followup cleanups after PR but let's turn it on by
default to shake out all the problems.

.github/workflows/release.yml

@@ -188,16 +188,10 @@ jobs:
           . .github/workflows/scripts/common-utils.sh
           prepare-build-cache
 
-      - name: Download Pre-Built LLVM 10.0.0
-        run: python misc/ci_download.py
-        env:
-          CI_PLATFORM: macos
-
       - name: Create Python Wheel
         run: |
           # Use the molten-vk v1.1.10 downloaded from taichi assets
           brew uninstall molten-vk -f
-          export PATH=$(pwd)/taichi-llvm/bin/:$PATH
           .github/workflows/scripts/unix-build.sh
         env:
           PROJECT_NAME: ${{ matrix.name }}
@@ -293,7 +287,7 @@ jobs:
         shell: pwsh
         if: ${{ needs.check_files.outputs.run_job != 'false' }}
         run: |
-          .\.github\workflows\scripts\win_build.ps1 -llvmVer 10 -installVulkan -libsDir "$env:LocalAppData/buildbot"
+          .\.github\workflows\scripts\win_build.ps1 -llvmVer 15 -installVulkan -libsDir "$env:LocalAppData/buildbot"
         env:
           PY: ${{ matrix.python }}
           PROJECT_NAME: ${{ matrix.name }}

.github/workflows/scripts/check_clang_tidy.sh

@@ -1,9 +1,14 @@
 #!/bin/bash
 
-CI_SETUP_CMAKE_ARGS=$1
+# TODO: move inside docker
+wget https://github.com/taichi-dev/taichi_assets/releases/download/llvm15/taichi-llvm-15-linux.zip
+unzip taichi-llvm-15-linux.zip && rm taichi-llvm-15-linux.zip
+export LLVM_DIR="$PWD/taichi-llvm-15"
 
-cd taichi
+pushd taichi
 python3 -m pip install -r requirements_dev.txt
 
+CI_SETUP_CMAKE_ARGS=$1
 export CI_SETUP_CMAKE_ARGS
 python3 ./scripts/run_clang_tidy.py $PWD/taichi -clang-tidy-binary clang-tidy-10 -header-filter=$PWD/taichi -j2
+popd

.github/workflows/scripts/unix-build.sh

@@ -6,24 +6,35 @@ set -ex
 
 [[ "$IN_DOCKER" == "true" ]] && cd taichi
 
-# TODO: Move llvm installation from container image to here
-if [[ "$LLVM_VERSION" == "15" ]]; then
-  if [[ $OSTYPE == "linux-"* ]]; then
-    wget https://github.com/ailzhang/torchhub_example/releases/download/0.2/taichi-llvm-15-linux.zip
+if [[ $OSTYPE == "linux-"* ]]; then
+  if [ ! -d ~/taichi-llvm-15 ]; then
+    pushd ~
+    wget https://github.com/taichi-dev/taichi_assets/releases/download/llvm15/taichi-llvm-15-linux.zip
     unzip taichi-llvm-15-linux.zip && rm taichi-llvm-15-linux.zip
-    export PATH="$PWD/taichi-llvm-15/bin:$PATH"
-  elif [ "$(uname -s):$(uname -m)" == "Darwin:arm64" ]; then
-    # The following commands are done manually to save time.
-    #wget https://github.com/ailzhang/torchhub_example/releases/download/0.2/taichi-llvm-15-m1.zip
-    #unzip taichi-llvm-15-m1.zip && rm taichi-llvm-15-m1.zip
-    export PATH="/Users/github/taichi-llvm-15-m1/bin:$PATH"
-  elif [ "$(uname -s):$(uname -m)" == "Darwin:x86_64" ]; then
-    # The following commands are done manually to save time.
-    #wget https://github.com/ailzhang/torchhub_example/releases/download/0.2/llvm-15-macos10.15.zip
-    #unzip llvm-15-macos10.15.zip && rm llvm-15-macos10.15.zip
-    export LLVM_DIR="~/llvm-15-mac10.15/"
+    popd
   fi
-  export TAICHI_CMAKE_ARGS="$TAICHI_CMAKE_ARGS -DTI_LLVM_15:BOOL=ON"
+
+  export LLVM_DIR="$HOME/taichi-llvm-15"
+elif [ "$(uname -s):$(uname -m)" == "Darwin:arm64" ]; then
+  # The following commands are done manually to save time.
+  if [ ! -d ~/taichi-llvm-15-m1 ]; then
+    pushd ~
+    wget https://github.com/taichi-dev/taichi_assets/releases/download/llvm15/taichi-llvm-15-m1.zip
+    unzip taichi-llvm-15-m1.zip && rm taichi-llvm-15-m1.zip
+    popd
+  fi
+
+  export LLVM_DIR="$HOME/taichi-llvm-15-m1"
+elif [ "$(uname -s):$(uname -m)" == "Darwin:x86_64" ]; then
+  # The following commands are done manually to save time.
+  if [ ! -d ~/llvm-15-mac10.15 ]; then
+    pushd ~
+    wget https://github.com/taichi-dev/taichi_assets/releases/download/llvm15/llvm-15-mac10.15.zip
+    unzip llvm-15-mac10.15.zip && rm llvm-15-mac10.15.zip
+    popd
+  fi
+
+  export LLVM_DIR="$HOME/llvm-15-mac10.15/"
 fi
 
 build_taichi_wheel() {

.github/workflows/testing.yml

@@ -149,7 +149,6 @@ jobs:
             -DTI_WITH_VULKAN:BOOL=ON
             -DTI_WITH_C_API=ON
             -DTI_BUILD_TESTS:BOOL=${{ matrix.with_cpp_tests }}
-          LLVM_VERSION: 15
 
       # [DEBUG] Copy this step around to enable debugging inside Github Action instances.
       #- name: Setup tmate session
@@ -214,7 +213,6 @@ jobs:
             -DTI_WITH_VULKAN:BOOL=ON
             -DTI_BUILD_TESTS:BOOL=ON
             -DTI_WITH_C_API=ON
-          LLVM_VERSION: 15
 
       - name: Test
         id: test
@@ -356,7 +354,6 @@ jobs:
             -DTI_WITH_VULKAN:BOOL=ON
             -DTI_BUILD_TESTS:BOOL=ON
             -DTI_WITH_C_API=ON
-          LLVM_VERSION: 15
 
       - name: Test
         id: test

cmake/TaichiCore.cmake

@@ -1,6 +1,6 @@
 option(USE_STDCPP "Use -stdlib=libc++" OFF)
 option(TI_WITH_LLVM "Build with LLVM backends" ON)
-option(TI_LLVM_15 "Switch to LLVM 15" OFF)
+option(TI_LLVM_15 "Switch to LLVM 15" ON)
 option(TI_WITH_METAL "Build with the Metal backend" ON)
 option(TI_WITH_CUDA "Build with the CUDA backend" ON)
 option(TI_WITH_CUDA_TOOLKIT "Build with the CUDA toolkit" OFF)