rust-cross: don't actually build a compiler

Instead of building a full compiler, we can use rust-native to
cross-compile.  All we need is a cross-compiled standard library, which
libstd-rs builds, and a compiler spec file.  rust-cross is now just used
to generate the json spec file for cross-compiling, which is naturally
much faster.

classes/cargo_util.bbclass

@@ -12,7 +12,7 @@ export CARGO_HOME = "${WORKDIR}/cargo_home"
 BASEDEPENDS_append = " cargo-native"
 
 # Ensure we get the right rust variant
-DEPENDS_append_class-target = " virtual/${TARGET_PREFIX}rust"
+DEPENDS_append_class-target = " virtual/${TARGET_PREFIX}rust ${RUSTLIB_DEP}"
 
 # Cargo only supports in-tree builds at the moment
 B = "${S}"

classes/rust-vars.bbclass

@@ -2,3 +2,7 @@ export rustlibdir = "${libdir}/rust"
 FILES_${PN} += "${rustlibdir}/*.so"
 FILES_${PN}-dev += "${rustlibdir}/*.rlib"
 FILES_${PN}-dbg += "${rustlibdir}/.debug"
+
+RUSTLIB = "-L ${STAGING_LIBDIR}/rust"
+RUSTFLAGS += "-C rpath -C crate_hash=${BB_TASKHASH} ${RUSTLIB}"
+RUSTLIB_DEP ?= "libstd-rs"

classes/rust.bbclass

@@ -2,11 +2,8 @@ inherit rust-vars
 
 RUSTC = "rustc"
 
-# FIXME: --sysroot might be needed
-RUSTFLAGS += "-C rpath -C crate_hash=${BB_TASKHASH}"
 RUSTC_ARCHFLAGS += "--target=${TARGET_SYS} ${RUSTFLAGS}"
 
-RUSTLIB_DEP ?= "rustlib"
 def rust_base_dep(d):
     # Taken from meta/classes/base.bbclass `base_dep_prepend` and modified to
     # use rust instead of gcc

recipes-devtools/rust/rust-cross.bb

@@ -10,6 +10,7 @@ INHIBIT_DEFAULT_RUST_DEPS = "1"
 # the bits we need explicitly.
 DEPENDS += "rust-llvm-native"
 DEPENDS += "virtual/${TARGET_PREFIX}gcc virtual/${TARGET_PREFIX}compilerlibs virtual/libc"
+DEPENDS += "rust-native"
 
 PROVIDES = "virtual/${TARGET_PREFIX}rust"
 PN = "rust-cross-${TARGET_ARCH}"
@@ -31,14 +32,18 @@ BUILD_POST_LINK_ARGS_append = " -Wl,-rpath=../../lib"
 # We need the same thing for the calls to the compiler when building the runtime crap
 TARGET_CC_ARCH_append = " --sysroot=${STAGING_DIR_TARGET}"
 
-# cross.bbclass is "helpful" and overrides our do_install. Tell it not to.
+do_configure () {
-do_install () {
-	rust_do_install
 }
 
-# using host-strip on target .so files generated by this recipie causes build errors.
+do_compile () {
-# for now, disable stripping.
+}
-# A better (but more complex) approach would be to mimic gcc-runtime and build
+
-# the target.so files in a seperate .bb file.
+do_install () {
-INHIBIT_PACKAGE_STRIP = "1"
+	mkdir -p ${D}${prefix}/${baselib}/rustlib
-INHIBIT_SYSROOT_STRIP = "1"
+	cp ${WORKDIR}/targets/${TARGET_ARCH}* ${D}${prefix}/${baselib}/rustlib
+}
+
+rust_cross_sysroot_preprocess() {
+    sysroot_stage_dir ${D}${prefix}/${baselib}/rustlib ${SYSROOT_DESTDIR}${prefix}/${baselib}/rustlib
+}
+SYSROOT_PREPROCESS_FUNCS += "rust_cross_sysroot_preprocess"

recipes-devtools/rust/rust.bb

@@ -1,3 +1,4 @@
+inherit rust-installer
 require rust.inc
 
 DEPENDS += "rust-llvm"

recipes-devtools/rust/rust.inc

@@ -1,6 +1,5 @@
 # ex: sts=4 et sw=4 ts=8
 inherit rust
-inherit rust-installer
 require rust-shared-source.inc
 require rust-snapshot-2016-05-24.inc
 

recipes-devtools/rust/rustlib.bb

@@ -1,26 +0,0 @@
-SUMMARY = "Rust runtime libaries"
-HOMEPAGE = "http://www.rust-lang.org"
-SECTION = "devel"
-LICENSE = "MIT | Apache-2.0"
-
-inherit rust-bin
-
-DEPENDS += "virtual/${TARGET_PREFIX}rust"
-RUSTLIB_DEP = ""
-
-do_install () {
-	for f in ${STAGING_DIR_NATIVE}/${rustlib_src}/*; do
-		echo Installing $f
-		install -D -m 755 $f ${D}/${rustlib}/$(basename $f)
-	done
-}
-
-# This has no license file
-python do_qa_configure() {
-        return True
-}
-
-FILES_${PN} += "${rustlib}/*.so"
-FILES_${PN}-dev += "${rustlib}/*.rlib"
-FILES_${PN}-staticdev += "${rustlib}/*.a"
-FILES_${PN}-dbg += "${rustlib}/.debug"