Improve android-ndk property interface

config.example.toml

@@ -30,7 +30,7 @@
 #
 # If `change-id` does not match the version that is currently running,
 # `x.py` will prompt you to update it and check the related PR for more details.
-change-id = 115898
+change-id = 116998
 
 # =============================================================================
 # Tweaking how LLVM is compiled
@@ -377,6 +377,9 @@ change-id = 115898
 # this is not intended to be used during local development.
 #metrics = false
 
+# Specify the location of the Android NDK. Used when targeting Android.
+#android-ndk = "/path/to/android-ndk-r25b"
+
 # =============================================================================
 # General install configuration options
 # =============================================================================
@@ -756,12 +759,6 @@ change-id = 115898
 # it must link to `libgcc_eh.a` to get a working output, and this option have no effect.
 #llvm-libunwind = 'no' if Linux, 'in-tree' if Fuchsia
 
-# If this target is for Android, this option will be required to specify where
-# the NDK for the target lives. This is used to find the C compiler to link and
-# build native code.
-# See `src/bootstrap/cc_detect.rs` for details.
-#android-ndk = <none> (path)
-
 # Build the sanitizer runtimes for this target.
 # This option will override the same option under [build] section.
 #sanitizers = build.sanitizers (bool)

src/bootstrap/bootstrap_test.py

@@ -103,7 +103,7 @@ class GenerateAndParseConfig(unittest.TestCase):
     """Test that we can serialize and deserialize a config.toml file"""
     def test_no_args(self):
         build = serialize_and_parse([])
-        self.assertEqual(build.get_toml("change-id"), '115898')
+        self.assertEqual(build.get_toml("change-id"), '116998')
         self.assertEqual(build.get_toml("profile"), 'dist')
         self.assertIsNone(build.get_toml("llvm.download-ci-llvm"))
 

src/bootstrap/configure.py

@@ -97,20 +97,7 @@ def v(*args):
 v("llvm-config", None, "set path to llvm-config")
 v("llvm-filecheck", None, "set path to LLVM's FileCheck utility")
 v("python", "build.python", "set path to python")
-v("android-cross-path", "target.arm-linux-androideabi.android-ndk",
-  "Android NDK standalone path (deprecated)")
-v("i686-linux-android-ndk", "target.i686-linux-android.android-ndk",
-  "i686-linux-android NDK standalone path")
-v("arm-linux-androideabi-ndk", "target.arm-linux-androideabi.android-ndk",
-  "arm-linux-androideabi NDK standalone path")
-v("armv7-linux-androideabi-ndk", "target.armv7-linux-androideabi.android-ndk",
-  "armv7-linux-androideabi NDK standalone path")
-v("thumbv7neon-linux-androideabi-ndk", "target.thumbv7neon-linux-androideabi.android-ndk",
-  "thumbv7neon-linux-androideabi NDK standalone path")
-v("aarch64-linux-android-ndk", "target.aarch64-linux-android.android-ndk",
-  "aarch64-linux-android NDK standalone path")
-v("x86_64-linux-android-ndk", "target.x86_64-linux-android.android-ndk",
-  "x86_64-linux-android NDK standalone path")
+v("android-ndk", "build.android-ndk", "set path to Android NDK")
 v("musl-root", "target.x86_64-unknown-linux-musl.musl-root",
   "MUSL root installation directory (deprecated)")
 v("musl-root-x86_64", "target.x86_64-unknown-linux-musl.musl-root",

src/bootstrap/src/core/config/config.rs

@@ -21,7 +21,6 @@ use std::str::FromStr;
 use crate::core::build_steps::compile::CODEGEN_BACKEND_PREFIX;
 use crate::core::config::flags::{Color, Flags, Warnings};
 use crate::utils::cache::{Interned, INTERNER};
-use crate::utils::cc_detect::{ndk_compiler, Language};
 use crate::utils::channel::{self, GitInfo};
 use crate::utils::helpers::{exe, output, t};
 use build_helper::exit;
@@ -142,6 +141,7 @@ pub struct Config {
     pub color: Color,
     pub patch_binaries_for_nix: Option<bool>,
     pub stage0_metadata: Stage0Metadata,
+    pub android_ndk: Option<PathBuf>,
 
     pub stdout_is_tty: bool,
     pub stderr_is_tty: bool,
@@ -521,7 +521,6 @@ pub struct Target {
     pub ranlib: Option<PathBuf>,
     pub default_linker: Option<PathBuf>,
     pub linker: Option<PathBuf>,
-    pub ndk: Option<PathBuf>,
     pub sanitizers: Option<bool>,
     pub profiler: Option<StringOrBool>,
     pub rpath: Option<bool>,
@@ -799,6 +798,7 @@ define_config! {
         patch_binaries_for_nix: Option<bool> = "patch-binaries-for-nix",
         // NOTE: only parsed by bootstrap.py, `--feature build-metrics` enables metrics unconditionally
         metrics: Option<bool> = "metrics",
+        android_ndk: Option<PathBuf> = "android-ndk",
     }
 }
 
@@ -1039,7 +1039,6 @@ define_config! {
         llvm_has_rust_patches: Option<bool> = "llvm-has-rust-patches",
         llvm_filecheck: Option<String> = "llvm-filecheck",
         llvm_libunwind: Option<String> = "llvm-libunwind",
-        android_ndk: Option<String> = "android-ndk",
         sanitizers: Option<bool> = "sanitizers",
         profiler: Option<StringOrBool> = "profiler",
         rpath: Option<bool> = "rpath",
@@ -1320,6 +1319,7 @@ impl Config {
         config.python = build.python.map(PathBuf::from);
         config.reuse = build.reuse.map(PathBuf::from);
         config.submodules = build.submodules;
+        config.android_ndk = build.android_ndk;
         set(&mut config.low_priority, build.low_priority);
         set(&mut config.compiler_docs, build.compiler_docs);
         set(&mut config.library_docs_private_items, build.library_docs_private_items);
@@ -1600,18 +1600,11 @@ impl Config {
                     .llvm_libunwind
                     .as_ref()
                     .map(|v| v.parse().expect("failed to parse rust.llvm-libunwind"));
-                if let Some(ref s) = cfg.android_ndk {
-                    target.ndk = Some(config.src.join(s));
-                }
                 if let Some(s) = cfg.no_std {
                     target.no_std = s;
                 }
-                target.cc = cfg.cc.map(PathBuf::from).or_else(|| {
-                    target.ndk.as_ref().map(|ndk| ndk_compiler(Language::C, &triple, ndk))
-                });
-                target.cxx = cfg.cxx.map(PathBuf::from).or_else(|| {
-                    target.ndk.as_ref().map(|ndk| ndk_compiler(Language::CPlusPlus, &triple, ndk))
-                });
+                target.cc = cfg.cc.map(PathBuf::from);
+                target.cxx = cfg.cxx.map(PathBuf::from);
                 target.ar = cfg.ar.map(PathBuf::from);
                 target.ranlib = cfg.ranlib.map(PathBuf::from);
                 target.linker = cfg.linker.map(PathBuf::from);

src/bootstrap/src/lib.rs

@@ -78,7 +78,7 @@ const LLD_FILE_NAMES: &[&str] = &["ld.lld", "ld64.lld", "lld-link", "wasm-ld"];
 ///
 /// If you make any major changes (such as adding new values or changing default values), please
 /// ensure that the associated PR ID is added to the end of this list.
-pub const CONFIG_CHANGE_HISTORY: &[usize] = &[115898];
+pub const CONFIG_CHANGE_HISTORY: &[usize] = &[115898, 116998];
 
 /// Extra --check-cfg to add when building
 /// (Mode restriction, config name, config values (if any))

src/bootstrap/src/utils/cc_detect.rs

@@ -26,7 +26,7 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::{env, iter};
 
-use crate::core::config::{Target, TargetSelection};
+use crate::core::config::TargetSelection;
 use crate::utils::helpers::output;
 use crate::{Build, CLang, GitRepo};
 
@@ -107,10 +107,11 @@ pub fn find(build: &Build) {
 pub fn find_target(build: &Build, target: TargetSelection) {
     let mut cfg = new_cc_build(build, target);
     let config = build.config.target_config.get(&target);
-    if let Some(cc) = config.and_then(|c| c.cc.as_ref()) {
+    if let Some(cc) = config
+        .and_then(|c| c.cc.clone())
+        .or_else(|| default_compiler(&mut cfg, Language::C, target, build))
+    {
         cfg.compiler(cc);
-    } else {
-        set_compiler(&mut cfg, Language::C, target, config, build);
     }
 
     let compiler = cfg.get_compiler();
@@ -127,12 +128,12 @@ pub fn find_target(build: &Build, target: TargetSelection) {
     // We'll need one anyways if the target triple is also a host triple
     let mut cfg = new_cc_build(build, target);
     cfg.cpp(true);
-    let cxx_configured = if let Some(cxx) = config.and_then(|c| c.cxx.as_ref()) {
+    let cxx_configured = if let Some(cxx) = config
+        .and_then(|c| c.cxx.clone())
+        .or_else(|| default_compiler(&mut cfg, Language::CPlusPlus, target, build))
+    {
         cfg.compiler(cxx);
         true
-    } else if build.hosts.contains(&target) || build.build == target {
-        set_compiler(&mut cfg, Language::CPlusPlus, target, config, build);
-        true
     } else {
         // Use an auto-detected compiler (or one configured via `CXX_target_triple` env vars).
         cfg.try_get_compiler().is_ok()
@@ -161,68 +162,70 @@ pub fn find_target(build: &Build, target: TargetSelection) {
     }
 }
 
-fn set_compiler(
+fn default_compiler(
     cfg: &mut cc::Build,
     compiler: Language,
     target: TargetSelection,
-    config: Option<&Target>,
     build: &Build,
-) {
+) -> Option<PathBuf> {
     match &*target.triple {
         // When compiling for android we may have the NDK configured in the
         // config.toml in which case we look there. Otherwise the default
         // compiler already takes into account the triple in question.
-        t if t.contains("android") => {
-            if let Some(ndk) = config.and_then(|c| c.ndk.as_ref()) {
-                cfg.compiler(ndk_compiler(compiler, &*target.triple, ndk));
-            }
-        }
+        t if t.contains("android") => build
+            .config
+            .android_ndk
+            .as_ref()
+            .map(|ndk| ndk_compiler(compiler, &*target.triple, ndk)),
 
         // The default gcc version from OpenBSD may be too old, try using egcc,
         // which is a gcc version from ports, if this is the case.
         t if t.contains("openbsd") => {
             let c = cfg.get_compiler();
             let gnu_compiler = compiler.gcc();
             if !c.path().ends_with(gnu_compiler) {
-                return;
+                return None;
             }
 
             let output = output(c.to_command().arg("--version"));
-            let i = match output.find(" 4.") {
-                Some(i) => i,
-                None => return,
-            };
+            let i = output.find(" 4.")?;
             match output[i + 3..].chars().next().unwrap() {
                 '0'..='6' => {}
-                _ => return,
+                _ => return None,
             }
             let alternative = format!("e{gnu_compiler}");
             if Command::new(&alternative).output().is_ok() {
-                cfg.compiler(alternative);
+                Some(PathBuf::from(alternative))
+            } else {
+                None
             }
         }
 
-        "mips-unknown-linux-musl" => {
+        "mips-unknown-linux-musl" if compiler == Language::C => {
             if cfg.get_compiler().path().to_str() == Some("gcc") {
-                cfg.compiler("mips-linux-musl-gcc");
+                Some(PathBuf::from("mips-linux-musl-gcc"))
+            } else {
+                None
             }
         }
-        "mipsel-unknown-linux-musl" => {
+        "mipsel-unknown-linux-musl" if compiler == Language::C => {
             if cfg.get_compiler().path().to_str() == Some("gcc") {
-                cfg.compiler("mipsel-linux-musl-gcc");
+                Some(PathBuf::from("mipsel-linux-musl-gcc"))
+            } else {
+                None
             }
         }
 
-        t if t.contains("musl") => {
+        t if t.contains("musl") && compiler == Language::C => {
             if let Some(root) = build.musl_root(target) {
                 let guess = root.join("bin/musl-gcc");
-                if guess.exists() {
-                    cfg.compiler(guess);
-                }
+                if guess.exists() { Some(guess) } else { None }
+            } else {
+                None
             }
         }
 
-        _ => {}
+        _ => None,
     }
 }
 
@@ -243,10 +246,22 @@ pub(crate) fn ndk_compiler(compiler: Language, triple: &str, ndk: &Path) -> Path
     let api_level =
         if triple.contains("aarch64") || triple.contains("x86_64") { "21" } else { "19" };
     let compiler = format!("{}{}-{}", triple_translated, api_level, compiler.clang());
-    ndk.join("bin").join(compiler)
+    let host_tag = if cfg!(target_os = "macos") {
+        // The NDK uses universal binaries, so this is correct even on ARM.
+        "darwin-x86_64"
+    } else if cfg!(target_os = "windows") {
+        "windows-x86_64"
+    } else {
+        // NDK r25b only has official releases for macOS, Windows and Linux.
+        // Try the Linux directory everywhere else, on the assumption that the OS has an
+        // emulation layer that can cope (e.g. BSDs).
+        "linux-x86_64"
+    };
+    ndk.join("toolchains").join("llvm").join("prebuilt").join(host_tag).join("bin").join(compiler)
 }
 
 /// The target programming language for a native compiler.
+#[derive(PartialEq)]
 pub(crate) enum Language {
     /// The compiler is targeting C.
     C,

src/ci/docker/host-x86_64/arm-android/Dockerfile

@@ -30,7 +30,7 @@ ENV PATH=$PATH:/android/sdk/platform-tools
 
 ENV TARGETS=arm-linux-androideabi
 
-ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/
+ENV RUST_CONFIGURE_ARGS --android-ndk=/android/ndk/
 
 ENV SCRIPT python3 ../x.py --stage 2 test --host='' --target $TARGETS
 

src/ci/docker/host-x86_64/dist-android/Dockerfile

@@ -19,12 +19,7 @@ ENV TARGETS=$TARGETS,x86_64-linux-android
 ENV RUST_CONFIGURE_ARGS \
       --enable-extended \
       --enable-profiler \
-      --arm-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
-      --armv7-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
-      --thumbv7neon-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
-      --i686-linux-android-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
-      --aarch64-linux-android-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
-      --x86_64-linux-android-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
+      --android-ndk=/android/ndk/ \
       --disable-docs
 
 ENV SCRIPT python3 ../x.py dist --host='' --target $TARGETS