Rollup merge of rust-lang#56947 - hsivonen:neon, r=alexcrichton

Add targets thumbv7neon-linux-androideabi and thumbv7neon-unknown-linux-gnueabihf

These two targets enable both thumb-mode and NEON for ARMv7 CPUs.

This another attempt at rust-lang#49902, which cannot be reopened. Between that PR and this one, some subrepos with C code whose build systems were failing went away.

Author: pietroalbini

src/bootstrap/cc_detect.rs

@@ -143,7 +143,10 @@ fn set_compiler(cfg: &mut cc::Build,
         // 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()) {
-                let target = target.replace("armv7", "arm");
+                let target = target.replace("armv7neon", "arm")
+                                   .replace("armv7", "arm")
+                                   .replace("thumbv7neon", "arm")
+                                   .replace("thumbv7", "arm");
                 let compiler = format!("{}-{}", target, compiler.clang());
                 cfg.compiler(ndk.join("bin").join(compiler));
             }

src/bootstrap/configure.py

@@ -107,6 +107,8 @@ def v(*args):
   "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",

src/ci/docker/dist-android/Dockerfile

@@ -16,6 +16,7 @@ RUN . /scripts/android-ndk.sh && \
 # env
 ENV TARGETS=arm-linux-androideabi
 ENV TARGETS=$TARGETS,armv7-linux-androideabi
+ENV TARGETS=$TARGETS,thumbv7neon-linux-androideabi
 ENV TARGETS=$TARGETS,i686-linux-android
 ENV TARGETS=$TARGETS,aarch64-linux-android
 ENV TARGETS=$TARGETS,x86_64-linux-android
@@ -24,6 +25,7 @@ ENV RUST_CONFIGURE_ARGS \
       --enable-extended \
       --arm-linux-androideabi-ndk=/android/ndk/arm-14 \
       --armv7-linux-androideabi-ndk=/android/ndk/arm-14 \
+      --thumbv7neon-linux-androideabi-ndk=/android/ndk/arm-14 \
       --i686-linux-android-ndk=/android/ndk/x86-14 \
       --aarch64-linux-android-ndk=/android/ndk/arm64-21 \
       --x86_64-linux-android-ndk=/android/ndk/x86_64-21 \

src/librustc_target/spec/armv7_linux_androideabi.rs

@@ -10,6 +10,11 @@
 
 use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
+// This target if is for the baseline of the Android v7a ABI
+// in thumb mode. It's named armv7-* instead of thumbv7-*
+// for historical reasons. See the thumbv7neon variant for
+// enabling NEON.
+
 // See https://developer.android.com/ndk/guides/abis.html#v7a
 // for target ABI requirements.
 

src/librustc_target/spec/armv7_unknown_linux_gnueabihf.rs

@@ -10,6 +10,9 @@
 
 use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
+// This target is for glibc Linux on ARMv7 without NEON or
+// thumb-mode. See the thumbv7neon variant for enabling both.
+
 pub fn target() -> TargetResult {
     let base = super::linux_base::opts();
     Ok(Target {

src/librustc_target/spec/armv7_unknown_linux_musleabihf.rs

@@ -10,6 +10,8 @@
 
 use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
+// This target is for musl Linux on ARMv7 without thumb-mode or NEON.
+
 pub fn target() -> TargetResult {
     let base = super::linux_musl_base::opts();
     Ok(Target {

src/librustc_target/spec/mod.rs

@@ -314,6 +314,7 @@ supported_targets! {
     ("armv5te-unknown-linux-gnueabi", armv5te_unknown_linux_gnueabi),
     ("armv5te-unknown-linux-musleabi", armv5te_unknown_linux_musleabi),
     ("armv7-unknown-linux-gnueabihf", armv7_unknown_linux_gnueabihf),
+    ("thumbv7neon-unknown-linux-gnueabihf", thumbv7neon_unknown_linux_gnueabihf),
     ("armv7-unknown-linux-musleabihf", armv7_unknown_linux_musleabihf),
     ("aarch64-unknown-linux-gnu", aarch64_unknown_linux_gnu),
 
@@ -331,6 +332,7 @@ supported_targets! {
     ("x86_64-linux-android", x86_64_linux_android),
     ("arm-linux-androideabi", arm_linux_androideabi),
     ("armv7-linux-androideabi", armv7_linux_androideabi),
+    ("thumbv7neon-linux-androideabi", thumbv7neon_linux_androideabi),
     ("aarch64-linux-android", aarch64_linux_android),
 
     ("aarch64-unknown-freebsd", aarch64_unknown_freebsd),

src/librustc_target/spec/thumbv7neon_linux_androideabi.rs

@@ -0,0 +1,44 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+
+// This target if is for the Android v7a ABI in thumb mode with
+// NEON unconditionally enabled and, therefore, with 32 FPU registers
+// enabled as well. See section A2.6.2 on page A2-56 in
+// https://static.docs.arm.com/ddi0406/cd/DDI0406C_d_armv7ar_arm.pdf
+
+// See https://developer.android.com/ndk/guides/abis.html#v7a
+// for target ABI requirements.
+
+pub fn target() -> TargetResult {
+    let mut base = super::android_base::opts();
+    base.features = "+v7,+thumb-mode,+thumb2,+vfp3,+neon".to_string();
+    base.max_atomic_width = Some(64);
+    base.pre_link_args
+        .get_mut(&LinkerFlavor::Gcc).unwrap().push("-march=armv7-a".to_string());
+
+    Ok(Target {
+        llvm_target: "armv7-none-linux-android".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "32".to_string(),
+        target_c_int_width: "32".to_string(),
+        data_layout: "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
+        arch: "arm".to_string(),
+        target_os: "android".to_string(),
+        target_env: "".to_string(),
+        target_vendor: "unknown".to_string(),
+        linker_flavor: LinkerFlavor::Gcc,
+        options: TargetOptions {
+            abi_blacklist: super::arm_base::abi_blacklist(),
+            .. base
+        },
+    })
+}

src/librustc_target/spec/thumbv7neon_unknown_linux_gnueabihf.rs

@@ -0,0 +1,42 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+
+// This target is for glibc Linux on ARMv7 with thumb mode enabled
+// (for consistency with Android and Debian-based distributions)
+// and with NEON unconditionally enabled and, therefore, with 32 FPU
+// registers enabled as well. See section A2.6.2 on page A2-56 in
+// https://static.docs.arm.com/ddi0406/cd/DDI0406C_d_armv7ar_arm.pdf
+
+pub fn target() -> TargetResult {
+    let base = super::linux_base::opts();
+    Ok(Target {
+        llvm_target: "armv7-unknown-linux-gnueabihf".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "32".to_string(),
+        target_c_int_width: "32".to_string(),
+        data_layout: "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
+        arch: "arm".to_string(),
+        target_os: "linux".to_string(),
+        target_env: "gnu".to_string(),
+        target_vendor: "unknown".to_string(),
+        linker_flavor: LinkerFlavor::Gcc,
+
+        options: TargetOptions {
+            // Info about features at https://wiki.debian.org/ArmHardFloatPort
+            features: "+v7,+thumb-mode,+thumb2,+vfp3,+neon".to_string(),
+            cpu: "generic".to_string(),
+            max_atomic_width: Some(64),
+            abi_blacklist: super::arm_base::abi_blacklist(),
+            .. base
+        }
+    })
+}

src/test/run-make-fulldeps/atomic-lock-free/Makefile

@@ -18,6 +18,8 @@ ifeq ($(filter arm,$(LLVM_COMPONENTS)),arm)
 	nm "$(TMPDIR)/libatomic_lock_free.rlib" | $(CGREP) -v __atomic_fetch_add
 	$(RUSTC) --target=armv7-unknown-linux-gnueabihf atomic_lock_free.rs
 	nm "$(TMPDIR)/libatomic_lock_free.rlib" | $(CGREP) -v __atomic_fetch_add
+	$(RUSTC) --target=thumbv7neon-unknown-linux-gnueabihf atomic_lock_free.rs
+	nm "$(TMPDIR)/libatomic_lock_free.rlib" | $(CGREP) -v __atomic_fetch_add
 endif
 ifeq ($(filter aarch64,$(LLVM_COMPONENTS)),aarch64)
 	$(RUSTC) --target=aarch64-unknown-linux-gnu atomic_lock_free.rs

src/tools/build-manifest/src/main.rs

@@ -61,7 +61,9 @@ static TARGETS: &'static [&'static str] = &[
     "armv5te-unknown-linux-musleabi",
     "armv7-apple-ios",
     "armv7-linux-androideabi",
+    "thumbv7neon-linux-androideabi",
     "armv7-unknown-linux-gnueabihf",
+    "thumbv7neon-unknown-linux-gnueabihf",
     "armv7-unknown-linux-musleabihf",
     "armebv7r-none-eabi",
     "armebv7r-none-eabihf",

src/tools/compiletest/src/runtest.rs

@@ -168,7 +168,10 @@ pub fn make_diff(expected: &str, actual: &str, context_size: usize) -> Vec<Misma
 
 pub fn run(config: Config, testpaths: &TestPaths, revision: Option<&str>) {
     match &*config.target {
-        "arm-linux-androideabi" | "armv7-linux-androideabi" | "aarch64-linux-android" => {
+        "arm-linux-androideabi"
+        | "armv7-linux-androideabi"
+        | "thumbv7neon-linux-androideabi"
+        | "aarch64-linux-android" => {
             if !config.adb_device_status {
                 panic!("android device not available");
             }