gnu: Add mrustc.

* gnu/packages/rust.scm (mrustc): New variable.

gnu/packages/rust.scm

@@ -6,6 +6,7 @@
 ;;; Copyright © 2017, 2018 Nikolai Merinov <nikolai.merinov@member.fsf.org>
 ;;; Copyright © 2017 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2018 Tobias Geerinckx-Rice <me@tobias.gr>
+;;; Copyright © 2018 Danny Milosavljevic <dannym+a@scratchpost.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -46,6 +47,7 @@
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system trivial)
   #:use-module (guix download)
+  #:use-module (guix git-download)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
   #:use-module ((guix build utils) #:select (alist-replace))
@@ -250,6 +252,92 @@ safety and thread safety guarantees.")
                     (alist-replace "rustc-bootstrap" (list base-rust)
                                    (package-native-inputs base-rust))))))
 
+(define-public mrustc
+  (let ((commit "1a16def28935548e29be0fe5a632e25c83045924")
+        (revision "0")
+        (rustc-version "1.19.0"))
+    (package
+      (name "mrustc")
+      (version (git-version "0.0.0" revision commit))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                      (url "https://github.com/thepowersgang/mrustc.git")
+                      (commit commit)))
+                (file-name (git-file-name name version))
+                (sha256
+                 (base32
+                  "0i5kqnzsd1rkj8qm147jx934nyn9sd1fz2b4achj9z0r00h84dh6"))))
+      (outputs '("out" "cargo"))
+      (build-system gnu-build-system)
+      (inputs
+       `(("llvm" ,llvm-3.9.1)))
+      (native-inputs
+       `(("bison" ,bison)
+         ("flex" ,flex)
+         ;; Required for the libstd sources.
+         ("rustc"
+          ,(rust-source "1.19.0" "0l8c14qsf42rmkqy92ahij4vf356dbyspxcips1aswpvad81y8qm"))))
+      (arguments
+       `(#:tests? #f
+         #:make-flags (list (string-append "LLVM_CONFIG="
+                                           (assoc-ref %build-inputs "llvm")
+                                           "/bin/llvm-config"))
+         #:phases
+         (modify-phases %standard-phases
+           (add-after 'unpack 'unpack-target-compiler
+             (lambda* (#:key inputs outputs #:allow-other-keys)
+               (substitute* "minicargo.mk"
+                 ;; Don't try to build LLVM.
+                 (("^[$][(]LLVM_CONFIG[)]:") "xxx:")
+                 ;; Build for the correct target architecture.
+                 (("^RUSTC_TARGET := x86_64-unknown-linux-gnu")
+                  (string-append "RUSTC_TARGET := "
+                                 ,(or (%current-target-system)
+                                      (nix-system->gnu-triplet
+                                       (%current-system))))))
+               (invoke "tar" "xf" (assoc-ref inputs "rustc"))
+               (chdir "rustc-1.19.0-src")
+               (invoke "patch" "-p0" "../rust_src.patch")
+               (chdir "..")
+               #t))
+           (delete 'configure)
+           (add-after 'build 'build-minicargo
+             (lambda _
+               (for-each (lambda (target)
+                           (invoke "make" "-f" "minicargo.mk" target))
+                         '("output/libstd.hir" "output/libpanic_unwind.hir"
+                           "output/libproc_macro.hir" "output/libtest.hir"))
+               ;; Technically the above already does it - but we want to be clear.
+               (invoke "make" "-C" "tools/minicargo")))
+           (replace 'install
+             (lambda* (#:key inputs outputs #:allow-other-keys)
+               (let* ((out (assoc-ref outputs "out"))
+                      (bin (string-append out "/bin"))
+                      (tools-bin (string-append out "/tools/bin"))
+                      (cargo-out (assoc-ref outputs "cargo"))
+                      (cargo-bin (string-append cargo-out "/bin"))
+                      (lib (string-append out "/lib"))
+                      (lib/rust (string-append lib "/mrust"))
+                      (gcc (assoc-ref inputs "gcc")))
+                 ;; These files are not reproducible.
+                 (for-each delete-file (find-files "output" "\\.txt$"))
+                 (mkdir-p lib)
+                 (copy-recursively "output" lib/rust)
+                 (mkdir-p bin)
+                 (mkdir-p tools-bin)
+                 (install-file "bin/mrustc" bin)
+                 ;; minicargo uses relative paths to resolve mrustc.
+                 (install-file "tools/bin/minicargo" tools-bin)
+                 (install-file "tools/bin/minicargo" cargo-bin)
+                 #t))))))
+      (synopsis "Compiler for the Rust progamming language")
+      (description "Rust is a systems programming language that provides memory
+safety and thread safety guarantees.")
+      (home-page "https://github.com/thepowersgang/mrustc")
+      ;; Dual licensed.
+      (license (list license:asl2.0 license:expat)))))
+
 (define-public rust-1.23
   (package
     (inherit rust-1.19)