rust: add support for armv6l-linux and armv7l-linux

pkgs/build-support/rust/build-rust-crate/build-crate.nix

···
-{ lib, stdenv, echo_build_heading, noisily, makeDeps }:
+{ lib, stdenv, echo_build_heading, noisily, makeDeps, rust }:
 { crateName,
   dependencies,
   crateFeatures, crateRenames, libName, release, libPath,
···
         (if release then "-C opt-level=3" else "-C debuginfo=2")
         (["-C codegen-units=$NIX_BUILD_CORES"] ++ extraRustcOpts);
     rustcMeta = "-C metadata=${metadata} -C extra-filename=-${metadata}";
-
-    # Some platforms have different names for rustc.
-    rustPlatform =
-      with stdenv.hostPlatform.parsed;
-      let cpu_ = if cpu.name == "armv7a" then "armv7"
-                 else cpu.name;
-          vendor_ = vendor.name;
-          kernel_ = kernel.name;
-          abi_ = abi.name;
-      in
-      "${cpu_}-${vendor_}-${kernel_}-${abi_}";
   in ''
     runHook preBuild
     norm=""
···
         ${crateFeatures} --out-dir target/bin --emit=dep-info,link -L dependency=target/deps \
         $LINK ${deps}$EXTRA_LIB --cap-lints allow \
         $BUILD_OUT_DIR $EXTRA_BUILD $EXTRA_FEATURES --color ${colors} \
-        ${if stdenv.hostPlatform != stdenv.buildPlatform then "--target ${rustPlatform} -C linker=${stdenv.hostPlatform.config}-gcc" else ""}
+        ${if stdenv.hostPlatform != stdenv.buildPlatform then "--target ${rust.toRustTarget stdenv.hostPlatform} -C linker=${stdenv.hostPlatform.config}-gcc" else ""}
       if [ "$crate_name_" != "$crate_name" ]; then
         mv target/bin/$crate_name_ target/bin/$crate_name
       fi

pkgs/build-support/rust/build-rust-crate/default.nix

···
 # This can be useful for deploying packages with NixOps, and to share
 # binary dependencies between projects.
 
-{ lib, stdenv, defaultCrateOverrides, fetchCrate, rustc }:
+{ lib, stdenv, defaultCrateOverrides, fetchCrate, rustc, rust }:
 
 let
     # This doesn't appear to be officially documented anywhere yet.
···
     '';
 
     configureCrate = import ./configure-crate.nix { inherit lib stdenv echo_build_heading noisily makeDeps; };
-    buildCrate = import ./build-crate.nix { inherit lib stdenv echo_build_heading noisily makeDeps; };
+    buildCrate = import ./build-crate.nix { inherit lib stdenv echo_build_heading noisily makeDeps rust; };
     installCrate = import ./install-crate.nix;
 
     in

pkgs/build-support/rust/default.nix

···
-{ stdenv, cacert, git, cargo, rustc, fetchcargo, buildPackages, windows }:
+{ stdenv, cacert, git, rust, cargo, rustc, fetchcargo, buildPackages, windows }:
 
 { name ? "${args.pname}-${args.version}"
 , cargoSha256 ? "unset"
···
       cargoDepsCopy="$sourceRoot/${cargoVendorDir}"
     '';
 
-  hostConfig = stdenv.hostPlatform.config;
-
-  rustHostConfig = {
-    x86_64-pc-mingw32 = "x86_64-pc-windows-gnu";
-  }.${hostConfig} or hostConfig;
-  rustTarget = if target == null then rustHostConfig else target;
+  rustTarget = if target == null then rust.toRustTarget stdenv.hostPlatform else target;
 
   ccForBuild="${buildPackages.stdenv.cc}/bin/${buildPackages.stdenv.cc.targetPrefix}cc";
   cxxForBuild="${buildPackages.stdenv.cc}/bin/${buildPackages.stdenv.cc.targetPrefix}c++";
···
       --subst-var-by vendor "$(pwd)/$cargoDepsCopy"
 
     cat >> .cargo/config <<'EOF'
-    [target."${stdenv.buildPlatform.config}"]
+    [target."${rust.toRustTarget stdenv.buildPlatform}"]
     "linker" = "${ccForBuild}"
     ${stdenv.lib.optionalString (stdenv.buildPlatform.config != stdenv.hostPlatform.config) ''
     [target."${rustTarget}"]
···
     (
     set -x
     env \
-      "CC_${stdenv.buildPlatform.config}"="${ccForBuild}" \
-      "CXX_${stdenv.buildPlatform.config}"="${cxxForBuild}" \
-      "CC_${stdenv.hostPlatform.config}"="${ccForHost}" \
-      "CXX_${stdenv.hostPlatform.config}"="${cxxForHost}" \
+      "CC_${rust.toRustTarget stdenv.buildPlatform}"="${ccForBuild}" \
+      "CXX_${rust.toRustTarget stdenv.buildPlatform}"="${cxxForBuild}" \
+      "CC_${rust.toRustTarget stdenv.hostPlatform}"="${ccForHost}" \
+      "CXX_${rust.toRustTarget stdenv.hostPlatform}"="${cxxForHost}" \
       cargo build \
         ${stdenv.lib.optionalString (buildType == "release") "--release"} \
         --target ${rustTarget} \

pkgs/development/compilers/rust/1_38_0.nix

···
   bootstrapHashes = {
     i686-unknown-linux-gnu = "74510e0e52a55e65a9f716673c2cda4d2bd427e2453541c6993c77c3ec04acf9";
     x86_64-unknown-linux-gnu = "cb573229bfd32928177c3835fdeb62d52da64806b844bc1095c6225b0665a1cb";
+    arm-unknown-linux-gnueabihf = "272739fbb23cf6c2040c1813af9c8c7f386cac37d9de638f22a1816eb96bc0ae";
     armv7-unknown-linux-gnueabihf = "5b87b877f0ed20c6a09ce26e7a15d8c61b26b62484b97e78a51099d0efefec98";
     aarch64-unknown-linux-gnu = "263ef98fa3a6b2911b56f89c06615cdebf6ef676eb9b2493ad1539602f79b6ba";
     i686-apple-darwin = "e45d0c4d882fc6c404ffa6fe790294f4ea96384a2b48804adbf723f3635477a8";

pkgs/development/compilers/rust/1_39_0.nix

···
   bootstrapHashes = {
     i686-unknown-linux-gnu = "41aed8a350e24a0cac1444ed99b3dd24a90bc581dd88cb420c6e547d6b5f57af";
     x86_64-unknown-linux-gnu = "adda26b3f0609dbfbdc2019da4a20101879b9db2134fae322a4e863a069ec221";
+    arm-unknown-linux-gnueabihf = "0603a3d3d16ae8f3b3b117eb699e8f3ef7532a6f6d3c29d13e7d4614fc3c9e7a";
     armv7-unknown-linux-gnueabihf = "8b1bf1680a61a643d6b5c7a3b1a1ce88448652756395e20ba5846739cbd085c4";
     aarch64-unknown-linux-gnu = "06afd6d525326cea95c3aa658aaa8542eab26f44235565bb16913ac9d12b7bda";
     i686-apple-darwin = "cdbf2807774bed350a3af6f41d7f7dd7ceff28777cde310c3ba90033188eb2f8";

pkgs/development/compilers/rust/bootstrap.nix

···
-{ stdenv, fetchurl, callPackage, version, hashes }:
+{ stdenv, fetchurl, rust, callPackage, version, hashes }:
 
 let
-  platform =
-    if stdenv.hostPlatform.system == "i686-linux"
-    then "i686-unknown-linux-gnu"
-    else if stdenv.hostPlatform.system == "x86_64-linux"
-    then "x86_64-unknown-linux-gnu"
-    else if stdenv.hostPlatform.system == "armv7l-linux"
-    then "armv7-unknown-linux-gnueabihf"
-    else if stdenv.hostPlatform.system == "aarch64-linux"
-    then "aarch64-unknown-linux-gnu"
-    else if stdenv.hostPlatform.system == "i686-darwin"
-    then "i686-apple-darwin"
-    else if stdenv.hostPlatform.system == "x86_64-darwin"
-    then "x86_64-apple-darwin"
-    else throw "missing bootstrap url for platform ${stdenv.hostPlatform.system}";
+  platform = rust.toRustTarget stdenv.hostPlatform;
 
   src = fetchurl {
      url = "https://static.rust-lang.org/dist/rust-${version}-${platform}.tar.gz";
-     sha256 = hashes.${platform};
+     sha256 = hashes.${platform} or (throw "missing bootstrap url for platform ${platform}");
   };
 
 in callPackage ./binary.nix

pkgs/development/compilers/rust/default.nix

···
 , llvmPackages_5
 , pkgsBuildTarget, pkgsBuildBuild
 }: rec {
+  toRustTarget = platform: with platform.parsed; let
+    cpu_ = {
+      "armv7a" = "armv7";
+      "armv7l" = "armv7";
+      "armv6l" = "arm";
+    }.${cpu.name} or cpu.name;
+  in "${cpu_}-${vendor.name}-${kernel.name}${lib.optionalString (abi.name != "unknown") "-${abi.name}"}";
+
   makeRustPlatform = { rustc, cargo, ... }: {
     rust = {
       inherit rustc cargo;

pkgs/development/compilers/rust/print-hashes.sh

···
 PLATFORMS=(
   i686-unknown-linux-gnu
   x86_64-unknown-linux-gnu
+  arm-unknown-linux-gnueabihf
   armv7-unknown-linux-gnueabihf
   aarch64-unknown-linux-gnu
   i686-apple-darwin

pkgs/development/compilers/rust/rustc.nix

···
 { stdenv, removeReferencesTo, pkgsBuildBuild, pkgsBuildHost, pkgsBuildTarget
 , fetchurl, file, python2
-, llvm_9, darwin, git, cmake, rustPlatform
+, llvm_9, darwin, git, cmake, rust, rustPlatform
 , pkgconfig, openssl
 , which, libffi
 , withBundledLLVM ? false
···
   # We need rust to build rust. If we don't provide it, configure will try to download it.
   # Reference: https://github.com/rust-lang/rust/blob/master/src/bootstrap/configure.py
   configureFlags = let
-    setBuild  = "--set=target.${stdenv.buildPlatform.config}";
-    setHost   = "--set=target.${stdenv.hostPlatform.config}";
-    setTarget = "--set=target.${stdenv.targetPlatform.config}";
+    setBuild  = "--set=target.${rust.toRustTarget stdenv.buildPlatform}";
+    setHost   = "--set=target.${rust.toRustTarget stdenv.hostPlatform}";
+    setTarget = "--set=target.${rust.toRustTarget stdenv.targetPlatform}";
     ccForBuild  = "${pkgsBuildBuild.targetPackages.stdenv.cc}/bin/${pkgsBuildBuild.targetPackages.stdenv.cc.targetPrefix}cc";
     cxxForBuild = "${pkgsBuildBuild.targetPackages.stdenv.cc}/bin/${pkgsBuildBuild.targetPackages.stdenv.cc.targetPrefix}c++";
     ccForHost  = "${pkgsBuildHost.targetPackages.stdenv.cc}/bin/${pkgsBuildHost.targetPackages.stdenv.cc.targetPrefix}cc";
···
     "--set=build.cargo=${rustPlatform.rust.cargo}/bin/cargo"
     "--enable-rpath"
     "--enable-vendor"
-    "--build=${stdenv.buildPlatform.config}"
-    "--host=${stdenv.hostPlatform.config}"
-    "--target=${stdenv.targetPlatform.config}"
+    "--build=${rust.toRustTarget stdenv.buildPlatform}"
+    "--host=${rust.toRustTarget stdenv.hostPlatform}"
+    "--target=${rust.toRustTarget stdenv.targetPlatform}"
 
     "${setBuild}.cc=${ccForBuild}"
     "${setHost}.cc=${ccForHost}"