ci: use cross for musl x86_64 builds

This is necessary because jemalloc + musl + Ubuntu 16.04 is apparently
broken.

Moreover, jemalloc doesn't support i686, so we accept the performance
regression there.

See also: gnzlbg/jemallocator#124

Author: BurntSushi

Cargo.toml

@@ -61,7 +61,7 @@ version = "2.32.0"
 default-features = false
 features = ["suggestions"]
 
-[target.'cfg(target_env = "musl")'.dependencies.jemallocator]
+[target.'cfg(all(target_env = "musl", target_pointer_width = "64"))'.dependencies.jemallocator]
 version = "0.3.0"
 
 [build-dependencies]

ci/before_deploy.sh

@@ -8,12 +8,13 @@ set -ex
 
 # Generate artifacts for release
 mk_artifacts() {
+    CARGO="$(builder)"
     if is_arm; then
-        cargo build --target "$TARGET" --release
+        "$CARGO" build --target "$TARGET" --release
     else
         # Technically, MUSL builds will force PCRE2 to get statically compiled,
         # but we also want PCRE2 statically build for macOS binaries.
-        PCRE2_SYS_STATIC=1 cargo build --target "$TARGET" --release --features 'pcre2'
+        PCRE2_SYS_STATIC=1 "$CARGO" build --target "$TARGET" --release --features 'pcre2'
     fi
 }
 

ci/script.sh

@@ -7,11 +7,13 @@ set -ex
 . "$(dirname $0)/utils.sh"
 
 main() {
+    CARGO="$(builder)"
+
     # Test a normal debug build.
     if is_arm; then
-        cargo build --target "$TARGET" --verbose
+        "$CARGO" build --target "$TARGET" --verbose
     else
-        cargo build --target "$TARGET" --verbose --all --features 'pcre2'
+        "$CARGO" build --target "$TARGET" --verbose --all --features 'pcre2'
     fi
 
     # Show the output of the most recent build.rs stderr.
@@ -44,7 +46,7 @@ main() {
     "$(dirname "${0}")/test_complete.sh"
 
     # Run tests for ripgrep and all sub-crates.
-    cargo test --target "$TARGET" --verbose --all --features 'pcre2'
+    "$CARGO" test --target "$TARGET" --verbose --all --features 'pcre2'
 }
 
 main

ci/utils.sh

@@ -55,13 +55,27 @@ gcc_prefix() {
     esac
 }
 
+is_musl() {
+    case "$TARGET" in
+        *-musl) return 0 ;;
+        *)      return 1 ;;
+    esac
+}
+
 is_x86() {
     case "$(architecture)" in
       amd64|i386) return 0 ;;
       *)          return 1 ;;
     esac
 }
 
+is_x86_64() {
+    case "$(architecture)" in
+      amd64) return 0 ;;
+      *)          return 1 ;;
+    esac
+}
+
 is_arm() {
     case "$(architecture)" in
         armhf) return 0 ;;
@@ -82,3 +96,12 @@ is_osx() {
         *)   return 1 ;;
     esac
 }
+
+builder() {
+    if is_musl && is_x86_64; then
+        cargo install cross
+        echo "cross"
+    else
+        echo "cargo"
+    fi
+}

src/main.rs

@@ -35,7 +35,10 @@ mod subject;
 // We don't unconditionally use jemalloc because it can be nice to use the
 // system's default allocator by default. Moreover, jemalloc seems to increase
 // compilation times by a bit.
-#[cfg(target_env = "musl")]
+//
+// Moreover, we only do this on 64-bit systems since jemalloc doesn't support
+// i686.
+#[cfg(all(target_env = "musl", target_pointer_width = "64"))]
 #[global_allocator]
 static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;