CI/CD: Add aarch64-unknown-linux-gnu test code coverage.

aarch64-unknown-linux-musl doesn't have profiler_builtins enabled so
use aarch64-unknown-linux-gnu instead.

Work around an issue where the "%m" feature of the LLVM source-based code
coverage doesn't work within QEMU.

Author: briansmith

.github/workflows/ci.yml

@@ -265,6 +265,7 @@ jobs:
 
         # TODO: targets
         target:
+          - aarch64-unknown-linux-gnu
           - i686-unknown-linux-gnu
           - x86_64-unknown-linux-musl
 
@@ -277,6 +278,9 @@ jobs:
 
         # TODO: targets
         include:
+          - target: aarch64-unknown-linux-gnu
+            host_os: ubuntu-18.04
+
           - target: i686-unknown-linux-gnu
             host_os: ubuntu-18.04
 

mk/cargo.sh

@@ -45,8 +45,9 @@ case $target in
     export CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER=$android_tools/aarch64-linux-android21-clang
     ;;
   aarch64-unknown-linux-gnu)
-    export CC_aarch64_unknown_linux_gnu=aarch64-linux-gnu-gcc
-    export AR_aarch64_unknown_linux_gnu=aarch64-linux-gnu-gcc-ar
+    export CC_aarch64_unknown_linux_gnu=clang-10
+    export AR_aarch64_unknown_linux_gnu=llvm-ar-10
+    export CFLAGS_aarch64_unknown_linux_gnu="--sysroot=/usr/aarch64-linux-gnu"
     export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER=aarch64-linux-gnu-gcc
     export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUNNER="$qemu_aarch64"
     ;;
@@ -107,7 +108,9 @@ if [ -n "${RING_COVERAGE-}" ]; then
   export RING_BUILD_EXECUTABLE_LIST="$coverage_dir/executables"
   truncate --size=0 "$RING_BUILD_EXECUTABLE_LIST"
 
-  export LLVM_PROFILE_FILE="$coverage_dir/%m.profraw"
+  # This doesn't work when profiling under QEMU. Instead mk/runner does
+  # something similar but different.
+  # export LLVM_PROFILE_FILE="$coverage_dir/%m.profraw"
 
   # ${target} with hyphens replaced by underscores, lowercase and uppercase.
   target_lower=${target//-/_}

mk/install-build-tools.sh

@@ -38,6 +38,8 @@ esac
 
 case $target in
 --target=aarch64-unknown-linux-gnu)
+  # Clang is needed for code coverage.
+  use_clang=1
   install_packages \
     qemu-user \
     gcc-aarch64-linux-gnu \

mk/runner

@@ -2,8 +2,20 @@
 set -eux -o pipefail
 IFS=$'\n\t'
 
+for arg in $*; do
+  # There can be some arguments prefixed in front of the executable, e.g.
+  # when qemu-user is used. There can be arguments after the executable,
+  # e.g. `cargo test` arguments like `TESTNAME`.
+  if [[ $arg = */deps/* ]]; then
+    executable=$arg
+    break
+  fi
+done
+
+export LLVM_PROFILE_FILE=$(dirname "$RING_BUILD_EXECUTABLE_LIST")/$(basename "$executable").profraw
+
 if [ -n "$RING_BUILD_EXECUTABLE_LIST" ]; then
-  echo $1 >> "$RING_BUILD_EXECUTABLE_LIST"
+  echo "$executable" >> "$RING_BUILD_EXECUTABLE_LIST"
 fi
 
 $*