Improvements to Rust's Installation (#15395)

* Add sources and resources for each version of Rust

* install bootstrapping compiler into stage

* Add libgit2

* Install bootstrapping compiler correctly

* implement full rust bootstrap

* Remove support for Rust pre-1.14

Also add lots of comments

* Support only Rust 1.17 and newer

* Remove < 1.23 versions of Rust

* Change the layout of rust_releases for maintainability

* Remove LLVM variant

* Address flake8 issues

* Make libgit2 curl variant default False, conflict 0.28 and newer

* Remove binutils dependency

* Add ARM64 while we're at it

* flake8

* use the 'python' routine rather than relying on the correct python to be picked up

2 files changed, 513 insertions, 46 deletions

diff --git a/var/spack/repos/builtin/packages/libgit2/package.py b/var/spack/repos/builtin/packages/libgit2/package.py
index 58ea638de0..222075ffdb 100644
--- a/var/spack/repos/builtin/packages/libgit2/package.py
+++ b/var/spack/repos/builtin/packages/libgit2/package.py
@@ -16,8 +16,79 @@ class Libgit2(CMakePackage):
     homepage = "https://libgit2.github.com/"
     url      = "https://github.com/libgit2/libgit2/archive/v0.26.0.tar.gz"
 
-    version('0.28.2', sha256='42b5f1e9b9159d66d86fff0394215c5733b6ef8f9b9d054cdd8c73ad47177fc3')
-    version('0.26.0', sha256='6a62393e0ceb37d02fe0d5707713f504e7acac9006ef33da1e88960bd78b6eac')
+    version('0.99.0',  sha256='174024310c1563097a6613a0d3f7539d11a9a86517cd67ce533849065de08a11')
+    version('0.28.4',  sha256='30f3877469d09f2e4a21be933b4e2800560d16646028dd800744dc5f7fb0c749')
+    version('0.28.3',  sha256='ee5344730fe11ce7c86646e19c2d257757be293f5a567548d398fb3af8b8e53b')
+    version('0.28.2',  sha256='42b5f1e9b9159d66d86fff0394215c5733b6ef8f9b9d054cdd8c73ad47177fc3')
+    version('0.28.1',  sha256='0ca11048795b0d6338f2e57717370208c2c97ad66c6d5eac0c97a8827d13936b')
+    version('0.28.0',  sha256='9d60d64dc77085e8e530e5c66314057eafe0c06e4a7a61149a70ff3e0688f284')
+    version('0.27.10', sha256='f6fd26378ff71bd7a4b17b576c82c774a2e9c2d6b74b24718a8fb29551e1c4a5')
+    version('0.27.9',  sha256='adf17310b590e6e7618f070c742b5ee028aeeed2c60099bc4190c386b5060de1')
+    version('0.27.8',  sha256='8313873d49dc01e8b880ec334d7430ae67496a89aaa8c6e7bbd3affb47a00c76')
+    version('0.27.7',  sha256='1a5435a483759b1cd96feb12b11abb5231b0688016db506ce5947178f6ba2531')
+    version('0.27.6',  sha256='d98db2ed11ec82fee94dce4819b466524613852c2c9c3426d351c57729ec49da')
+    version('0.27.5',  sha256='15f2775f4f325951d9139ed906502b6c71fee6787cada9b045f5994072ccbd33')
+    version('0.27.4',  sha256='0b7ca31cb959ff1b22afa0da8621782afe61f99242bf716c403802ffbdb21d51')
+    version('0.27.3',  sha256='50a57bd91f57aa310fb7d5e2a340b3779dc17e67b4e7e66111feac5c2432f1a5')
+    version('0.27.2',  sha256='ffacdbd5588aeb03e98e3866a7e2ceace468723a439bdc9bb01362fe140fa9e5')
+    version('0.27.1',  sha256='837b11927bc5f64e7f9ab0376f57cfe3ca5aa52ffd2007ac41184b21124fb086')
+    version('0.27.0',  sha256='545b0458292c786aba334f1bf1c8f73600ae73dd7205a7bb791a187ee48ab8d2')
+    version('0.26.8',  sha256='0f20d7e239be030db33d7350bab38ada2830b3bffab5539730074e71b0267796')
+    version('0.26.7',  sha256='65584ac1f4de2c3ab8491351c8629eb68bad2d65e67f6411bf0333b8976dc4ef')
+    version('0.26.6',  sha256='7669dd47ebdab86ced8888816c552596ec923b6e126704a3445b2081cb0e5662')
+    version('0.26.5',  sha256='52e28a5166564bc4365a2e4112f5e5c6e334708dbf13596241b2fd34efc1b0a9')
+    version('0.26.4',  sha256='292fa2600bbb4e52641793cfcc1c19ffc0bf97b5fd8378d422a6bfe7afffcb97')
+    version('0.26.3',  sha256='0da4e211dfb63c22e5f43f2a4a5373e86a140afa88a25ca6ba3cc2cae58263d2')
+    version('0.26.2',  sha256='747b47d5b02a2387ff81301c694763785181b895690b6eb91ed1ae4b7904307b')
+    version('0.26.1',  sha256='68cd0f8ee9e0ca84dcf0f0267d0a8297471d3365622d22d3da67c57165bb0722')
+    version('0.26.0',  sha256='6a62393e0ceb37d02fe0d5707713f504e7acac9006ef33da1e88960bd78b6eac')
 
-    depends_on('cmake@2.8:', type='build')
-    depends_on('libssh2')
+    # Backends
+    variant(
+        'https', default='system', description='HTTPS support',
+        values=('system', 'openssl', 'none'), multi=False)
+    variant('ssh', default=True, description='Enable SSH support')
+    variant('curl', default=False, description='Enable libcurl support (only supported through v0.27)')
+
+    # Build Dependencies
+    depends_on('cmake@2.8:', type='build', when="@:0.28")
+    depends_on('cmake@3.5:', type='build', when="@0.99:")
+
+    # Runtime Dependencies
+    depends_on('libssh2', when='+ssh')
+    depends_on('openssl', when='https=system platform=linux')
+    depends_on('openssl', when='https=system platform=cray')
+    depends_on('openssl', when='https=openssl')
+    depends_on('curl', when='+curl')
+
+    conflicts('+curl', when='@0.28:')
+
+    def cmake_args(self):
+        args = []
+        if 'https=system' in self.spec:
+            if 'platform=linux' in self.spec or 'platform=cray' in self.spec:
+                args.append('-DUSE_HTTPS=OpenSSL')
+            elif 'platform=darwin' in self.spec:
+                args.append('-DUSE_HTTPS=SecureTransport')
+            else:
+                # Let CMake try to find an HTTPS implementation. Mileage on
+                # your platform may vary
+                args.append('-DUSE_HTTPS=ON')
+        elif 'https=openssl' in self.spec:
+            args.append('-DUSE_HTTPS=OpenSSL')
+        else:
+            args.append('-DUSE_HTTPS=OFF')
+
+        args.append(
+            '-DUSE_SSH={0}'.format('ON' if '+ssh' in self.spec else 'OFF'))
+
+        # The curl backed is not supported after 0.27.x
+        if '@:0.27 +curl' in self.spec:
+            args.append(
+                '-DCURL={0}'.format('ON' if '+curl' in self.spec else 'OFF'))
+
+        # Control tests
+        args.append(
+            '-DBUILD_CLAR={0}'.format('ON' if self.run_tests else 'OFF'))
+
+        return args
diff --git a/var/spack/repos/builtin/packages/rust/package.py b/var/spack/repos/builtin/packages/rust/package.py
index 2ae30b5c03..59e827f67d 100644
--- a/var/spack/repos/builtin/packages/rust/package.py
+++ b/var/spack/repos/builtin/packages/rust/package.py
@@ -4,59 +4,455 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 from spack import *
+from six import iteritems
 
 
 class Rust(Package):
-    """The rust programming language toolchain"""
+    """The Rust programming language toolchain
 
-    homepage = "http://www.rust-lang.org"
-    git      = "https://github.com/rust-lang/rust.git"
+    This package can bootstrap any version of the Rust compiler since Rust
+    1.23. It does this by downloading the platform-appropriate binary
+    distribution of the desired version of the rust compiler, and then building
+    that compiler from source.
+    """
 
-    version('develop', branch='master')
-    version('1.41.0', tag='1.41.0')
-    version('1.34.0', tag='1.34.0')
-    version('1.32.0', tag='1.32.0')
-    version('1.31.1', tag='1.31.1')
-    version('1.31.0', tag='1.31.0')  # "Rust 2018" edition
-    version('1.30.1', tag='1.30.1')
+    homepage = "https://www.rust-lang.org"
+    url = "https://static.rust-lang.org/dist/rustc-1.42.0-src.tar.gz"
+
+    maintainers = ["AndrewGaspar"]
+
+    phases = ['configure', 'build', 'install']
 
     extendable = True
 
-    # Rust
-    depends_on("llvm")
-    depends_on("curl")
-    depends_on("git")
-    depends_on("cmake")
-    depends_on("binutils")
-    depends_on("python@:2.8")
+    variant(
+        'rustfmt',
+        default=True,
+        description='Formatting tool for Rust code'
+    )
+
+    variant(
+        'analysis',
+        default=True,
+        description='Outputs code analysis that can be consumed by other tools'
+    )
+
+    variant(
+        'clippy',
+        default=True,
+        description='Linting tool for Rust'
+    )
+
+    variant(
+        'rls',
+        default=False,
+        description='The Rust Language Server can be used for IDE integration'
+    )
+
+    variant(
+        'src',
+        default=True,
+        description='Install Rust source files'
+    )
+
+    depends_on('cmake', type='build')
+    depends_on('python@:2.8', type='build')
+    depends_on('openssl')
+    depends_on('libssh2')
+    depends_on('libgit2')
+
+    # Version Notes:
+    # Here's some information on why your favorite Rust version may be missing.
+    #
+    # < 1.23:
+    # Rust seems to eagerly search for ar next to cc. Spack makes wrappers for
+    # cc and c++, but not for ar, so no ar is found. In future versions, ar
+    # can be specified in the config.
+    #
+    # < 1.17:
+    # The `x.py` bootstrapping script did not exist prior to Rust 1.17. It
+    # would be possible to support both, but for simplicitly, we only support
+    # Rust 1.17 and newer
+    version('1.42.0', sha256='d2e8f931d16a0539faaaacd801e0d92c58df190269014b2360c6ab2a90ee3475')
+    version('1.41.1', sha256='38c93d016e6d3e083aa15e8f65511d3b4983072c0218a529f5ee94dd1de84573')
+    version('1.41.0', sha256='5546822c09944c4d847968e9b7b3d0e299f143f307c00fa40e84a99fabf8d74b')
+    version('1.40.0', sha256='dd97005578defc10a482bff3e4e728350d2099c60ffcf1f5e189540c39a549ad')
+    version('1.39.0', sha256='b4a1f6b6a93931f270691aba4fc85eee032fecda973e6b9c774cd06857609357')
+    version('1.38.0', sha256='644263ca7c7106f8ee8fcde6bb16910d246b30668a74be20b8c7e0e9f4a52d80')
+    version('1.37.0', sha256='120e7020d065499cc6b28759ff04153bfdc2ac9b5adeb252331a4eb87cbe38c3')
+    version('1.36.0', sha256='04c4e4d7213d036d6aaed392841496d272146312c0290f728b7400fccd15bb1b')
+    version('1.35.0', sha256='5a4d637a716bac18d085f44dd87ef48b32195f71b967d872d80280b38cff712d')
+    version('1.34.2', sha256='c69a4a85a1c464368597df8878cb9e1121aae93e215616d45ad7d23af3052f56')
+    version('1.34.1', sha256='b0c785264d17e1dac4598627c248a2d5e07dd39b6666d1881fcfc8e2cf4c40a7')
+    version('1.34.0', sha256='7ac85acffd79dd3a7c44305d9eaabd1f1e7116e2e6e11e770e4bf5f92c0f1f59')
+    version('1.33.0', sha256='5a01a8d7e65126f6079042831385e77485fa5c014bf217e9f3e4aff36a485d94')
+    version('1.32.0', sha256='4c594c7712a0e7e8eae6526c464bf6ea1d82f77b4f61717c3fc28fb27ba2224a')
+    version('1.31.1', sha256='91d2fc22f08d986adab7a54eb3a6a9b99e490f677d2d092e5b9e4e069c23686a')
+    version('1.30.1', sha256='36a38902dbd9a3e1240d46ab0f2ca40d2fd07c2ab6508ed7970c6c4c036b5b29')
+    version('1.30.0', sha256='cd0ba83fcca55b64c0c9f23130fe731dfc1882b73ae21bef96be8f2362c108ee')
+    version('1.29.2', sha256='5088e796aa2e47478cdf41e7243fc5443fafab0a7c70a11423e57c80c04167c9')
+    version('1.29.1', sha256='f1b0728b66ce6bce6d72bbe5ea9e3a24ea22a045665da2ed8fcdfad14f61a349')
+    version('1.29.0', sha256='a4eb34ffd47f76afe2abd813f398512d5a19ef00989d37306217c9c9ec2f61e9')
+    version('1.28.0', sha256='1d5a81729c6f23a0a23b584dd249e35abe9c6f7569cee967cc42b1758ecd6486')
+    version('1.27.2', sha256='9a818c50cdb7880abeaa68b3d97792711e6c64c1cdfb6efdc23f75b8ced0e15d')
+    version('1.27.1', sha256='2133beb01ddc3aa09eebc769dd884533c6cfb08ce684f042497e097068d733d1')
+    version('1.27.0', sha256='2cb9803f690349c9fd429564d909ddd4676c68dc48b670b8ddf797c2613e2d21')
+    version('1.26.2', sha256='fb9ecf304488c9b56600ab20cfd1937482057f7e5db7899fddb86e0774548700')
+    version('1.26.1', sha256='70a7961bd8ec43b2c01e9896e90b0a06804a7fbe0a5c05acc7fd6fed19500df0')
+    version('1.26.0', sha256='4fb09bc4e233b71dcbe08a37a3f38cabc32219745ec6a628b18a55a1232281dd')
+    version('1.25.0', sha256='eef63a0aeea5147930a366aee78cbde248bb6e5c6868801bdf34849152965d2d')
+    version('1.24.1', sha256='3ea53d45e8d2e9a41afb3340cf54b9745f845b552d802d607707cf04450761ef')
+    version('1.24.0', sha256='bb8276f6044e877e447f29f566e4bbf820fa51fea2f912d59b73233ffd95639f')
+    version('1.23.0', sha256='7464953871dcfdfa8afcc536916a686dd156a83339d8ec4d5cb4eb2fe146cb91')
+
+    # The Rust bootstrapping process requires a bootstrapping compiler. The
+    # easiest way to do this is to download the binary distribution of the
+    # same version of the compiler and build with that.
+    #
+    # This dictionary contains a version: hash dictionary for each supported
+    # Rust target.
+    rust_releases = {
+        '1.42.0': {
+            'x86_64-unknown-linux-gnu':      '7d1e07ad9c8a33d8d039def7c0a131c5917aa3ea0af3d0cc399c6faf7b789052',
+            'powerpc64le-unknown-linux-gnu': '805b08fa1e0aad4d706301ca1f13e2d80810d385cece2c15070360b3c4bd6e4a',
+            'aarch64-unknown-linux-gnu':     'fdd39f856a062af265012861949ff6654e2b7103be034d046bec84ebe46e8d2d',
+            'x86_64-apple-darwin':           'db1055c46e0d54b99da05e88c71fea21b3897e74a4f5ff9390e934f3f050c0a8'
+        },
+        '1.41.1': {
+            'x86_64-unknown-linux-gnu':      'a6d5a3b3f574aafc8f787fea37aad9fb8a7946b383ae5348146927192ff0bef0',
+            'powerpc64le-unknown-linux-gnu': 'f9b53ca636625b3a2dd87600b6274223c11f866c9b5a34b638ea0013186659d3',
+            'aarch64-unknown-linux-gnu':     'd54c0f9165b86216b6f1b499f451141407939c5dc6b36c89a3772895a1370242',
+            'x86_64-apple-darwin':           '16615288cf74239783de1b435d329f3d56ed13803c7c10cd4b207d7c8ffa8f67'
+        },
+        '1.41.0': {
+            'x86_64-unknown-linux-gnu':      '343ba8ef7397eab7b3bb2382e5e4cb08835a87bff5c8074382c0b6930a41948b',
+            'powerpc64le-unknown-linux-gnu': 'ba231b0d8273d6928f61e2be3456e816a1de8050135e20c0623dc7a6ea03ba68',
+            'aarch64-unknown-linux-gnu':     '79ddfb5e2563d0ee09a567fbbe121a2aed3c3bc61255b2787f2dd42183a10f27',
+            'x86_64-apple-darwin':           'b6504003ab70b11f278e0243a43ba9d6bf75e8ad6819b4058a2b6e3991cc8d7a'
+        },
+        '1.40.0': {
+            'x86_64-unknown-linux-gnu':      'fc91f8b4bd18314e83a617f2389189fc7959146b7177b773370d62592d4b07d0',
+            'powerpc64le-unknown-linux-gnu': 'b1a23e35c383f99e647df6a9239b1dc9313e293deb70a76ba58e8ebe55ef623b',
+            'aarch64-unknown-linux-gnu':     '639271f59766d291ebdade6050e7d05d61cb5c822a3ef9a1e2ab185fed68d729',
+            'x86_64-apple-darwin':           '749ca5e0b94550369cc998416b8854c13157f5d11d35e9b3276064b6766bcb83'
+        },
+        '1.39.0': {
+            'x86_64-unknown-linux-gnu':      'b10a73e5ba90034fe51f0f02cb78f297ed3880deb7d3738aa09dc5a4d9704a25',
+            'powerpc64le-unknown-linux-gnu': '53b3fd942c52709f7e6fe11ea572d086e315a57a40b84b9b3290ac0ec8c7c84a',
+            'aarch64-unknown-linux-gnu':     'e27dc8112fe577012bd88f30e7c92dffd8c796478ce386c49465c03b6db8209f',
+            'x86_64-apple-darwin':           '3736d49c5e9592844e1a5d5452883aeaf8f1e25d671c1bc8f01e81c1766603b5'
+        },
+        '1.38.0': {
+            'x86_64-unknown-linux-gnu':      'adda26b3f0609dbfbdc2019da4a20101879b9db2134fae322a4e863a069ec221',
+            'powerpc64le-unknown-linux-gnu': 'f9ed1bb6525abdd4dd6ef10782ad45d2f71496e0c3c88e806b510c81a91c4ff7',
+            'aarch64-unknown-linux-gnu':     '06afd6d525326cea95c3aa658aaa8542eab26f44235565bb16913ac9d12b7bda',
+            'x86_64-apple-darwin':           'bd301b78ddcd5d4553962b115e1dca5436dd3755ed323f86f4485769286a8a5a'
+        },
+        '1.37.0': {
+            'x86_64-unknown-linux-gnu':      'cb573229bfd32928177c3835fdeb62d52da64806b844bc1095c6225b0665a1cb',
+            'powerpc64le-unknown-linux-gnu': '27c59ec40e9e9f71490dc00bf165156ae3ea77c20ffa4b5e5fd712e67527b477',
+            'aarch64-unknown-linux-gnu':     '263ef98fa3a6b2911b56f89c06615cdebf6ef676eb9b2493ad1539602f79b6ba',
+            'x86_64-apple-darwin':           'b2310c97ffb964f253c4088c8d29865f876a49da2a45305493af5b5c7a3ca73d'
+        },
+        '1.36.0': {
+            'x86_64-unknown-linux-gnu':      '15e592ec52f14a0586dcebc87a957e472c4544e07359314f6354e2b8bd284c55',
+            'powerpc64le-unknown-linux-gnu': '654a7a18d881811c09f630b0c917825b586e94a6142eceaede6b8046718e4054',
+            'aarch64-unknown-linux-gnu':     'db78c24d93756f9fe232f081dbc4a46d38f8eec98353a9e78b9b164f9628042d',
+            'x86_64-apple-darwin':           '91f151ec7e24f5b0645948d439fc25172ec4012f0584dd16c3fb1acb709aa325'
+        },
+        '1.35.0': {
+            'x86_64-unknown-linux-gnu':      'cf600e2273644d8629ed57559c70ca8db4023fd0156346facca9ab3ad3e8f86c',
+            'powerpc64le-unknown-linux-gnu': 'a933955adec386d75d126e78df5b9941936e156acb3353fc44b85995a81c7bb2',
+            'aarch64-unknown-linux-gnu':     '31e6da56e67838fd2874211ae896a433badf67c13a7b68481f1d5f7dedcc5952',
+            'x86_64-apple-darwin':           'ac14b1c7dc330dcb53d8641d74ebf9b32aa8b03b9d650bcb9258030d8b10dbd6'
+        },
+        '1.34.2': {
+            'x86_64-unknown-linux-gnu':      '2bf6622d980a52832bae141304e96f317c8a1ccd2dfd69a134a14033e6e43c0f',
+            'powerpc64le-unknown-linux-gnu': '4ddd55014bbd954b3499859bfa3146bff471de21c1d73fc6e7cccde290fc1918',
+            'aarch64-unknown-linux-gnu':     '15fc6b7ec121df9d4e42483dd12c677203680bec8c69b6f4f62e5a35a07341a8',
+            'x86_64-apple-darwin':           '6fdd4bf7fe26dded0cd57b41ab5f0500a5a99b7bc770523a425e9e34f63d0fd8'
+        },
+        '1.34.1': {
+            'x86_64-unknown-linux-gnu':      '8e2eead11bd5bf61409e29018d007c6fc874bcda2ff54db3d04d1691e779c14e',
+            'powerpc64le-unknown-linux-gnu': '94ac92d08afcfa2d77ae207e91b57c00cb48ff7ba08a27ed3deb2493f33e8fb1',
+            'aarch64-unknown-linux-gnu':     '0565e50dae58759a3a5287abd61b1a49dfc086c4d6acf2ce604fe1053f704e53',
+            'x86_64-apple-darwin':           'f4e46b9994ccfab4a84059298d1dc8fd446b1bbb7449462e0459948f7debea0e'
+        },
+        '1.34.0': {
+            'x86_64-unknown-linux-gnu':      '170647ed41b497dc937a6b2556700210bc4be187b1735029ef9ccf52e2cb5ab8',
+            'powerpc64le-unknown-linux-gnu': '3027e87802e161cce6f3a23d961f6d73b9ed6e829b2cd7af5dfccf6e1207e552',
+            'aarch64-unknown-linux-gnu':     '370c3a8fb9a69df36d645a95e622fb59ac5b513baecddde706cedaf20defa269',
+            'x86_64-apple-darwin':           'e6bea8d865cc7341c17fa3b8f25f7989e6b04f53e9da24878addc524f3a32664'
+        },
+        '1.33.0': {
+            'x86_64-unknown-linux-gnu':      '6623168b9ee9de79deb0d9274c577d741ea92003768660aca184e04fe774393f',
+            'powerpc64le-unknown-linux-gnu': 'db885aa4c2c6896c85257be2ade5c9edea660ca6878970683e8d5796618329b5',
+            'aarch64-unknown-linux-gnu':     'a308044e4076b62f637313ea803fa0a8f340b0f1b53136856f2c43afcabe5387',
+            'x86_64-apple-darwin':           '864e7c074a0b88e38883c87c169513d072300bb52e1d320a067bd34cf14f66bd'
+        },
+        '1.32.0': {
+            'x86_64-unknown-linux-gnu':      'e024698320d76b74daf0e6e71be3681a1e7923122e3ebd03673fcac3ecc23810',
+            'powerpc64le-unknown-linux-gnu': 'd6d5c9154f4459465d68ebd4fa1e17bad4b6cfe219667dddd9123c3bfb5dd839',
+            'aarch64-unknown-linux-gnu':     '60def40961728212da4b3a9767d5a2ddb748400e150a5f8a6d5aa0e1b8ba1cee',
+            'x86_64-apple-darwin':           'f0dfba507192f9b5c330b5984ba71d57d434475f3d62bd44a39201e36fa76304'
+        },
+        '1.31.1': {
+            'x86_64-unknown-linux-gnu':      'a64685535d0c457f49a8712a096a5c21564cd66fd2f7da739487f028192ebe3c',
+            'powerpc64le-unknown-linux-gnu': 'a6f61b7a8a06a2b0a785391cc3e6bb8004aa72095eea80db1561039f5bb3e975',
+            'aarch64-unknown-linux-gnu':     '29a7c6eb536fefd0ca459e48dfaea006aa8bff8a87aa82a9b7d483487033632a',
+            'x86_64-apple-darwin':           '8398b1b303bdf0e7605d08b87070a514a4f588797c6fb3593718cb9cec233ad6'
+        },
+        '1.30.1': {
+            'x86_64-unknown-linux-gnu':      'a01a493ed8946fc1c15f63e74fc53299b26ebf705938b4d04a388a746dfdbf9e',
+            'powerpc64le-unknown-linux-gnu': 'a7d4806e6702bdbad5017eeddc62f7ff7eb2438b1b9c39cbc90c2b1207f8e65f',
+            'aarch64-unknown-linux-gnu':     '6d87d81561285abd6c1987e07b60b2d723936f037c4b46eedcc12e8566fd3874',
+            'x86_64-apple-darwin':           '3ba1704a7defe3d9a6f0c1f68792c084da83bcba85e936d597bac0c019914b94'
+        },
+        '1.30.0': {
+            'x86_64-unknown-linux-gnu':      'f620e3125cc505c842150bd873c0603432b6cee984cdae8b226cf92c8aa1a80f',
+            'powerpc64le-unknown-linux-gnu': '0b53e257dc3d9f3d75cd97be569d3bf456d2c0af57ed0bd5e7a437227d8f465a',
+            'aarch64-unknown-linux-gnu':     '9690c7c50eba5a8461184ee4138b4c284bad31ccc4aa1f2ddeec58b253e6363e',
+            'x86_64-apple-darwin':           '07008d90932712282bc599f1e9a226e97879c758dc1f935e6e2675e45694cc1b'
+        },
+        '1.29.2': {
+            'x86_64-unknown-linux-gnu':      'e9809825c546969a9609ff94b2793c9107d7d9bed67d557ed9969e673137e8d8',
+            'powerpc64le-unknown-linux-gnu': '344003b808c20424c4699c9452bd37cdee23857dd4aa125e67d1d6e4bc992091',
+            'aarch64-unknown-linux-gnu':     'e11461015ca7106ef8ebf00859842bf4be518ee170226cb8eedaaa666946509f',
+            'x86_64-apple-darwin':           '63f54e3013406b39fcb5b84bcf5e8ce85860d0b97a1e156700e467bf5fb5d5f2'
+        },
+        '1.29.1': {
+            'x86_64-unknown-linux-gnu':      'b36998aea6d58525f25d89f1813b6bfd4cad6ff467e27bd11e761a20dde43745',
+            'powerpc64le-unknown-linux-gnu': '26a6d652ade6b6a96e6af18e846701ee28f912233372dfe15432139252f88958',
+            'aarch64-unknown-linux-gnu':     '2685224f67b2ef951e0e8b48829f786cbfed95e19448ba292ac33af719843dbe',
+            'x86_64-apple-darwin':           '07b07fbd6fab2390e19550beb8008745a8626cc5e97b72dc659061c1c3b3d008'
+        },
+        '1.29.0': {
+            'x86_64-unknown-linux-gnu':      '09f99986c17b1b6b1bfbc9dd8785e0e4693007c5feb67915395d115c1a3aea9d',
+            'powerpc64le-unknown-linux-gnu': 'd6954f1da53f7b3618fba3284330d99b6142bb25d9febba6dbfedad59ca53329',
+            'aarch64-unknown-linux-gnu':     '0ed3be0fd9f847afeb4e587fff61f6769ea61b53719d3ea999326284e8975b36',
+            'x86_64-apple-darwin':           '28a0473637585742f6d80ccd8afd88b6b400e65d623c33cb892412759444da93'
+        },
+        '1.28.0': {
+            'x86_64-unknown-linux-gnu':      '2a1390340db1d24a9498036884e6b2748e9b4b057fc5219694e298bdaa37b810',
+            'powerpc64le-unknown-linux-gnu': '255818156ec1f795ed808a44b4fdb8019187d5ebb7f837ae8f55a1ca40862bb6',
+            'aarch64-unknown-linux-gnu':     '9b6fbcee73070332c811c0ddff399fa31965bec62ef258656c0c90354f6231c1',
+            'x86_64-apple-darwin':           '5d7a70ed4701fe9410041c1eea025c95cad97e5b3d8acc46426f9ac4f9f02393'
+        },
+        '1.27.2': {
+            'x86_64-unknown-linux-gnu':      '5028a18e913ef3eb53e8d8119d2cc0594442725e055a9361012f8e26f754f2bf',
+            'powerpc64le-unknown-linux-gnu': '11034d150e811d4903b09fd42f0cb76d467a6365a158101493405fff1054572f',
+            'aarch64-unknown-linux-gnu':     'cf84da70269c0e50bb3cc3d248bae1ffcd70ee69dc5a4e3513b54fefc6685fb4',
+            'x86_64-apple-darwin':           '30c5cc58759caa4efdf2ea7d8438633139c98bee3408beb29ceb26985f3f5f70'
+        },
+        '1.27.1': {
+            'x86_64-unknown-linux-gnu':      '435778a837af764da2a7a7fb4d386b7b78516c7dfc732d892858e9a8a539989b',
+            'powerpc64le-unknown-linux-gnu': 'a08e6b6fed3329fcd1220b2ee4cd7a311d99121cf780fb6e1c6353bfeddfb176',
+            'aarch64-unknown-linux-gnu':     'd1146b240e6f628224c3a67e3aae2a57e6c25d544115e5ece9ce91861ec92b3a',
+            'x86_64-apple-darwin':           '475be237962d6aef1038a2faada26fda1e0eaea5d71d6950229a027a9c2bfe08'
+        },
+        '1.27.0': {
+            'x86_64-unknown-linux-gnu':      '235ad78e220b10a2d0267aea1e2c0f19ef5eaaff53ad6ff8b12c1d4370dec9a3',
+            'powerpc64le-unknown-linux-gnu': '847774a751e848568215739d384e3baf4d6ec37d27fb3add7a8789208c213aff',
+            'aarch64-unknown-linux-gnu':     'e74ebc33dc3fc19e501a677a87b619746efdba2901949a0319176352f556673a',
+            'x86_64-apple-darwin':           'a1d48190992e01aac1a181bce490c80cb2c1421724b4ff0e2fb7e224a958ce0f'
+        },
+        '1.26.2': {
+            'x86_64-unknown-linux-gnu':      'd2b4fb0c544874a73c463993bde122f031c34897bb1eeb653d2ba2b336db83e6',
+            'powerpc64le-unknown-linux-gnu': 'ea045869074ae3617eeb51207ce183e6915784b9ed615ecb92ce082ddb86ec1f',
+            'aarch64-unknown-linux-gnu':     '3dfad0dc9c795f7ee54c2099c9b7edf06b942adbbf02e9ed9e5d4b5e3f1f3759',
+            'x86_64-apple-darwin':           'f193705d4c0572a358670dbacbf0ffadcd04b3989728b442f4680fa1e065fa72'
+        },
+        '1.26.1': {
+            'x86_64-unknown-linux-gnu':      'b7e964bace1286696d511c287b945f3ece476ba77a231f0c31f1867dfa5080e0',
+            'powerpc64le-unknown-linux-gnu': 'ad8b2f6dd8c5cca1251d65b75ed2120aae3c5375d2c8ed690259cf4a652d7d3c',
+            'aarch64-unknown-linux-gnu':     'd4a369053c2dfd5f457de6853557dab563944579fa4bb55bc919bacf259bff6d',
+            'x86_64-apple-darwin':           'ebf898b9fa7e2aafc53682a41f18af5ca6660ebe82dd78f28cd9799fe4dc189a'
+        },
+        '1.26.0': {
+            'x86_64-unknown-linux-gnu':      '13691d7782577fc9f110924b26603ade1990de0b691a3ce2dc324b4a72a64a68',
+            'powerpc64le-unknown-linux-gnu': '3ba3a4905730ec01007ca1096d9fc3780f4e81f71139a619e1f526244301b7f4',
+            'aarch64-unknown-linux-gnu':     'e12dc84bdb569cdb382268a5fe6ae6a8e2e53810cb890ec3a7133c20ba8451ac',
+            'x86_64-apple-darwin':           '38708803c3096b8f101d1919ee2d7e723b0adf1bc1bb986b060973b57d8c7c28'
+        },
+        '1.25.0': {
+            'x86_64-unknown-linux-gnu':      '06fb45fb871330a2d1b32a27badfe9085847fe824c189ddc5204acbe27664f5e',
+            'powerpc64le-unknown-linux-gnu': '79eeb2a7fafa2e0f65f29a1dc360df69daa725347e4b6a533684f1c07308cc6e',
+            'aarch64-unknown-linux-gnu':     '19a43451439e515a216d0a885d14203f9a92502ee958abf86bf7000a7d73d73d',
+            'x86_64-apple-darwin':           'fcd0302b15e857ba4a80873360cf5453275973c64fa82e33bfbed02d88d0ad17'
+        },
+        '1.24.1': {
+            'x86_64-unknown-linux-gnu':      '4567e7f6e5e0be96e9a5a7f5149b5452828ab6a386099caca7931544f45d5327',
+            'powerpc64le-unknown-linux-gnu': '6f6c4bebbd7d6dc9989bf372c512dea55af8f56a1a0cfe97784667f0ac5430ee',
+            'aarch64-unknown-linux-gnu':     '64bb25a9689b18ddadf025b90d9bdb150b809ebfb74432dc69cc2e46120adbb2',
+            'x86_64-apple-darwin':           '9d4aacdb5849977ea619d399903c9378163bd9c76ea11dac5ef6eca27849f501'
+        },
+        '1.24.0': {
+            'x86_64-unknown-linux-gnu':      '336cf7af6c857cdaa110e1425719fa3a1652351098dc73f156e5bf02ed86443c',
+            'powerpc64le-unknown-linux-gnu': '25d9b965a63ad2f345897028094d4c7eafa432237b478754ccbcc299f80629c8',
+            'aarch64-unknown-linux-gnu':     'a981de306164b47f3d433c1d53936185260642849c79963af7e07d36b063a557',
+            'x86_64-apple-darwin':           '1aecba7cab4bc1a9e0e931c04aa00849e930b567d243da7b676ede8f527a2992'
+        },
+        '1.23.0': {
+            'x86_64-unknown-linux-gnu':      '9a34b23a82d7f3c91637e10ceefb424539dcfa327c2dcd292ff10c047b1fdc7e',
+            'powerpc64le-unknown-linux-gnu': '60f1a1cc182c516de08c1f42ada01604a3d94383e9dded6b237ae2233999437b',
+            'aarch64-unknown-linux-gnu':     '38379fbd976d2286cb73f21466db40a636a583b9f8a80af5eea73617c7912bc7',
+            'x86_64-apple-darwin':           '9274e977322bb4b153f092255ac9bd85041142c73eaabf900cb2ef3d3abb2eba'
+        }
+    }
+
+    # This dictionary maps Rust target architectures to Spack constraints that
+    # match that target.
+    rust_archs = {
+        'x86_64-unknown-linux-gnu': [
+            {'platform': 'linux', 'target': 'x86_64:'},
+            {'platform': 'cray', 'target': 'x86_64:'}
+        ],
+        'powerpc64le-unknown-linux-gnu': [
+            {'platform': 'linux', 'target': 'ppc64le:'},
+            {'platform': 'cray', 'target': 'ppc64le:'}
+        ],
+        'aarch64-unknown-linux-gnu': [
+            {'platform': 'linux', 'target': 'aarch64:'},
+            {'platform': 'cray', 'target': 'aarch64:'}
+        ],
+        'x86_64-apple-darwin': [
+            {'platform': 'darwin', 'target': 'x86_64:'}
+        ]
+    }
 
-    # Cargo
-    depends_on("openssl")
+    # This loop generates resources for each binary distribution, and maps
+    # them to the version of the compiler they bootstrap. This is in place
+    # of listing each resource explicitly, which would be potentially even
+    # more verbose.
+    #
+    # NOTE: This loop should technically specify the architecture to be the
+    # _host_ architecture, not the target architecture, in order to support
+    # cross compiling. I'm not sure Spack provides a way to specify a
+    # distinction in the when clause, though.
+    for rust_version, rust_targets in iteritems(rust_releases):
+        for rust_target, rust_sha256 in iteritems(rust_targets):
+            for rust_arch in rust_archs[rust_target]:
+                resource(
+                    name='rust-{version}-{target}'.format(
+                        version=rust_version,
+                        target=rust_target
+                    ),
+                    url='https://static.rust-lang.org/dist/rust-{version}-{target}.tar.gz'.format(
+                        version=rust_version,
+                        target=rust_target
+                    ),
+                    sha256=rust_sha256,
+                    destination='spack_bootstrap_stage',
+                    when='@{version} platform={platform} target={target}'\
+                        .format(
+                            version=rust_version,
+                            platform=rust_arch['platform'],
+                            target=rust_arch['target']
+                        )
+                )
 
-    phases = ['configure', 'install']
+    # This routine returns the target architecture we intend to build for.
+    def get_rust_target(self):
+        if 'platform=linux' in self.spec or 'platform=cray' in self.spec:
+            if 'target=x86_64:' in self.spec:
+                return 'x86_64-unknown-linux-gnu'
+            elif 'target=ppc64le:' in self.spec:
+                return 'powerpc64le-unknown-linux-gnu'
+            elif 'target=aarch64:' in self.spec:
+                return 'aarch64-unknown-linux-gnu'
+        elif 'platform=darwin target=x86_64:' in self.spec:
+            return 'x86_64-apple-darwin'
+
+        raise InstallError(
+            "rust is not supported for '{0}'".format(
+                self.spec.architecture
+            ))
 
     def configure(self, spec, prefix):
-        configure_args = [
-          '--prefix=%s' % prefix,
-          '--llvm-root=' + spec['llvm'].prefix,
-          # Workaround for "FileCheck does not exist" error
-          '--disable-codegen-tests',
-          # Includes Cargo in the build
-          # https://github.com/rust-lang/cargo/issues/3772#issuecomment-283109482
-          '--enable-extended',
-          # Prevent build from writing bash completion into system path
-          '--sysconfdir=%s' % join_path(prefix, 'etc/')
-          ]
-
-        configure(*configure_args)
-
-        # Build system defaults to searching in the same path as Spack's
-        # compiler wrappers which causes the build to fail
-        filter_file(
-            '#ar = "ar"',
-            'ar = "%s"' % join_path(spec['binutils'].prefix.bin, 'ar'),
-            'config.toml')
+        target = self.get_rust_target()
+        # See the NOTE above the resource loop - should be host architecture,
+        # not target aarchitecture if we're to support cross-compiling.
+        bootstrapping_install = Executable(
+            './spack_bootstrap_stage/rust-{version}-{target}/install.sh'
+            .format(
+                version=spec.version,
+                target=target
+            )
+        )
+        # install into the staging area
+        bootstrapping_install('--prefix={0}'.format(
+            join_path(self.stage.source_path, 'spack_bootstrap')
+        ))
+
+        boot_bin = join_path(self.stage.source_path, 'spack_bootstrap/bin')
+
+        # Always build rustc and cargo
+        tools = ['rustc', 'cargo']
+        # Only make additional components available in 'rust-bootstrap'
+        if '+rustfmt' in self.spec:
+            tools.append('rustfmt')
+        if '+analysis' in self.spec:
+            tools.append('analysis')
+        if '@1.33: +clippy' in self.spec:
+            tools.append('clippy')
+        if '+rls' in self.spec:
+            tools.append('rls')
+        if '+src' in self.spec:
+            tools.append('src')
+
+        ar = which('ar', required=True)
+
+        # build.tools was introduced in Rust 1.25
+        tools_spec = 'tools={0}'.format(tools) if '@1.25:' in self.spec else ''
+        # This is a temporary fix due to rust 1.42 breaking self bootstrapping
+        # See: https://github.com/rust-lang/rust/issues/69953
+        #
+        # In general, this should be safe because bootstrapping typically
+        # ensures everything but the bootstrapping script is warning free for
+        # the latest set of warning.
+        deny_warnings_spec = \
+            'deny-warnings = false' if '@1.42.0' in self.spec else ''
+
+        with open('config.toml', 'w') as out_file:
+            out_file.write("""\
+[build]
+cargo = "{cargo}"
+rustc = "{rustc}"
+docs = false
+vendor = true
+extended = true
+verbose = 2
+{tools_spec}
+
+[rust]
+channel = "stable"
+rpath = true
+{deny_warnings_spec}
+
+[target.{target}]
+ar = "{ar}"
+
+[install]
+prefix = "{prefix}"
+sysconfdir = "etc"
+""".format(
+                cargo=join_path(boot_bin, 'cargo'),
+                rustc=join_path(boot_bin, 'rustc'),
+                prefix=prefix,
+                target=target,
+                deny_warnings_spec=deny_warnings_spec,
+                ar=ar.path,
+                tools_spec=tools_spec
+            )
+            )
+
+    def build(self, spec, prefix):
+        python('./x.py', 'build', extra_env={
+            # vendored libgit2 wasn't correctly building (couldn't find the
+            # vendored libssh2), so let's just have spack build it
+            'LIBSSH2_SYS_USE_PKG_CONFIG': '1',
+            'LIBGIT2_SYS_USE_PKG_CONFIG': '1'
+        })
 
     def install(self, spec, prefix):
-        make()
-        make("install")
+        python('./x.py', 'install')