test-release.sh: Add support for cross-compiling

[tstellar]

Summary

To enable cross-compiling, pass a CMake toolchain file to the script using
the -toolchain-file option.

For example:
./test-release.sh -release 16.0.0 -final -toolchain-file pwd/aarch64-redhat-linux.cmake -triple aarch64-redhat-linux -use-ninja

[thieta]

Looks fine to me. But I am unsure if we need to have the toolchain file checked into LLVM. Wouldn't that be up to the person cross-compiling? Going to be hard to assume stuff there?

[barannikov88]

llvm/utils/release/aarch64-redhat-linux.cmake

5

How about splitting this into
CMAKE_SYSROOT and CMAKE_<LANG>_COMPILER_TARGET?
(This is what the CMake documentation suggests, I don't know if it works).

[thieta]

llvm/utils/release/aarch64-redhat-linux.cmake

5

Yeah that totally works and is the right way to handle that for sure.

Compared with my internal toolchain files this one seems very short and missing stuff. But I am not convinced that we should have one of these files in the LLVM repo in the first place.

[barannikov88]

But I am not convinced that we should have one of these files in the LLVM repo in the first place.

It could serve as an example. There is a bunch of CMake cache files in clang/cmake/caches and those are quite helpful in understanding how to build a toolchain.
It would be nice if this is mentioned in documentation, however.

llvm/utils/release/aarch64-redhat-linux.cmake

5

It might serve as an example.
Maybe in different directory though

[tstellar]

In D151385#4371866, @thieta wrote:

Looks fine to me. But I am unsure if we need to have the toolchain file checked into LLVM. Wouldn't that be up to the person cross-compiling? Going to be hard to assume stuff there?

I wanted to add cross-compile support so that we could build 'official' binaries using GitHub actions for other arches besides x86_64. For this scenario, I think it makes sense to have the toolchain file somewhere in tree, so that it is easy to reproduce the builds. This specific file works with a container image that I created with all the necessary cross-libs, which I would also like to put in tree somewhere.

[thieta]

In D151385#4371979, @tstellar wrote:

In D151385#4371866, @thieta wrote:

Looks fine to me. But I am unsure if we need to have the toolchain file checked into LLVM. Wouldn't that be up to the person cross-compiling? Going to be hard to assume stuff there?

I wanted to add cross-compile support so that we could build 'official' binaries using GitHub actions for other arches besides x86_64. For this scenario, I think it makes sense to have the toolchain file somewhere in tree, so that it is easy to reproduce the builds. This specific file works with a container image that I created with all the necessary cross-libs, which I would also like to put in tree somewhere.

I guess this makes sense for that use. I wonder if we shouldn't start putting these files (all files related to release management) in a new top-level directory like release or utils instead of shoving them under the llvm directory. I think it might make more sense and be easier to understand that they are universal instead of just related to the llvm sub-project.

llvm/utils/release/aarch64-redhat-linux.cmake

+set(CMAKE_SYSTEM_NAME Linux)
+
+set(TRIPLE "aarch64-redhat-linux")
+
+set(COMMON_COMPILE_FLAGS "-target ${TRIPLE} --sysroot=/usr/${TRIPLE}/")
+set(COMMON_LINK_FLAGS "-fuse-ld=lld")
+
+set(CMAKE_CXX_FLAGS ${COMMON_COMPILE_FLAGS})
+set(CMAKE_C_FLAGS ${COMMON_COMPILE_FLAGS})
+set(CMAKE_EXE_LINKER_FLAGS ${COMMON_LINK_FLAGS})
+set(CMAKE_MODULE_LINKER_FLAGS ${COMMON_LINK_FLAGS})
+set(CMAKE_SHARED_LINKER_FLAGS ${COMMON_LINK_FLAGS})
+
+set(LLVM_HOST_TRIPLE ${TRIPLE} CACHE STRING "Host on which LLVM binaries will run")

llvm/utils/release/test-release.sh

 #!/usr/bin/env bash
 #===-- test-release.sh - Test the LLVM release candidates ------------------===#
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===------------------------------------------------------------------------===#
 #
 # Download, build, and test the release candidate for an LLVM release.
 #
+# dnf install -y file clang ninja-build cmake chrpath
+# CXX=/usr/lib64/ccache/clang++ ./test-release.sh -no-libunwind -no-lldb -no-polly -no-mlir -no-flang -release 16.0.0 -final -toolchain-file `pwd`/aarch64-redhat-linux.cmake  -triple arch64-redhat-linux -use-ninja
 #===------------------------------------------------------------------------===#
 
 System=`uname -s`
 Machine=`uname -m`
 if [ "$System" = "FreeBSD" ]; then
     MAKE=gmake
 else
     MAKE=make

 do_polly="yes"
 do_mlir="yes"
 do_flang="yes"
 do_silent_log="no"
 BuildDir="`pwd`"
 ExtraConfigureFlags=""
 ExportBranch=""
 git_ref=""
+toolchain_file=""
 
 do_bolt="no"
 if [ "$System" = "Linux" ]; then
     case $Machine in
         x86_64 | arm64 | aarch64 )
             do_bolt="yes"
             ;;
     esac
function usage() {
     echo " -no-openmp           Disable check-out & build libomp"
     echo " -no-lld              Disable check-out & build lld"
     echo " -lldb                Enable check-out & build lldb"
     echo " -no-lldb             Disable check-out & build lldb (default)"
     echo " -no-polly            Disable check-out & build Polly"
     echo " -no-mlir             Disable check-out & build MLIR"
     echo " -no-flang            Disable check-out & build Flang"
     echo " -silent-log          Don't output build logs to stdout"
+    echo " -toolchain-file FILE Path to toolchain file to use for cross-compiling stage3."
 }
 
 while [ $# -gt 0 ]; do
     case $1 in
         -release | --release )
             shift
             Release="$1"
             Release_no_dot="`echo $1 | sed -e 's,\.,,g'`"
case $1 in
             do_mlir="no"
             ;;
         -no-flang )
             do_flang="no"
             ;;
         -silent-log )
             do_silent_log="yes"
             ;;
+        -toolchain-file )
+            shift
+            toolchain_file="$1"
+            do_compare="no"
+            # Disable libunwind build due to configure error:
+            #   Compiler doesn't support generation of unwind tables if exception support
+            #   is disabled.  Building libunwind DSO with runtime dependency on C++ ABI
+            #   library is not supported.
+            do_libunwind="no"
+            # --sysroot option is not passed to libcxxabi builds.
+            do_libcxxabi="no"
+            do_libs="no"
+
+            ;;
         -help | --help | -h | --h | -\? )
             usage
             exit 0
             ;;
         * )
             echo "unknown option: $1"
             usage
             exit 1
function configure_llvmCore() {
     # since this phase is only meant to get a clang compiler, capable of
     # building itself and any selected runtimes in the second phase.
     if [ "$Phase" -lt "2" ]; then
       runtime_list=""
     else
       runtime_list="$runtimes"
     fi
 
+    if [ "$Phase" -eq "3" ] && [ -n "$toolchain_file" ]; then
+      ExtraConfigureFlags="$ExtraConfigureFlags -DCMAKE_TOOLCHAIN_FILE=$toolchain_file"
+    fi
     echo "# Using C compiler: $c_compiler"
     echo "# Using C++ compiler: $cxx_compiler"
 
     cd $ObjDir
     echo "# Configuring llvm $Release-$RC $Flavor"
 
     echo "#" env CC="$c_compiler" CXX="$cxx_compiler" \
         cmake -G "$generator" \
build_llvmCore 3 $Flavor \
         $llvmCore_phase3_objdir $llvmCore_phase3_destdir
     clean_RPATH $llvmCore_phase3_destdir/usr/local
 
     ########################################################################
     # Testing: Test phase 3
     c_compiler=$llvmCore_phase3_destdir/usr/local/bin/clang
     cxx_compiler=$llvmCore_phase3_destdir/usr/local/bin/clang++
     echo "# Testing - built with clang"
+    # Disable tests if we are cross-compiling
+    if [ -z "$toolchain_file" ]; then
       test_llvmCore 3 $Flavor $llvmCore_phase3_objdir
+    fi
 
     ########################################################################
     # Compare .o files between Phase2 and Phase3 and report which ones
     # differ.
     if [ "$do_compare" = "yes" ]; then
         echo
         echo "# Comparing Phase 2 and Phase 3 files"
         for p2 in `find $llvmCore_phase2_objdir -name '*.o'` ; do