From 7d3c2a54ad66d5c4b2aa96eb946537fac1a5ae75 Mon Sep 17 00:00:00 2001
From: Pierre Langlois <pierre.langlois@gmx.com>
Date: Sun, 16 Jan 2022 16:55:59 +0000
Subject: [PATCH] gnu: Add wasm32-wasi-clang-toolchain.

WIP
---
 gnu/local.mk          |   1 +
 gnu/packages/llvm.scm |   1 +
 gnu/packages/wasm.scm | 273 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 275 insertions(+)
 create mode 100644 gnu/packages/wasm.scm

diff --git a/gnu/local.mk b/gnu/local.mk
index b7339ff472..952786827f 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -603,6 +603,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/packages/vpn.scm				\
   %D%/packages/vulkan.scm			\
   %D%/packages/w3m.scm				\
+  %D%/packages/wasm.scm			\
   %D%/packages/wdiff.scm			\
   %D%/packages/web.scm				\
   %D%/packages/web-browsers.scm			\
diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
index eb949bed1b..8821b2b6a7 100644
--- a/gnu/packages/llvm.scm
+++ b/gnu/packages/llvm.scm
@@ -74,6 +74,7 @@ (define-module (gnu packages llvm)
   #:use-module (srfi srfi-1)
   #:use-module (ice-9 match)
   #:export (make-lld-wrapper
+            clang-from-llvm
             system->llvm-target))
 
 (define* (system->llvm-target #:optional
diff --git a/gnu/packages/wasm.scm b/gnu/packages/wasm.scm
new file mode 100644
index 0000000000..f9f73505ef
--- /dev/null
+++ b/gnu/packages/wasm.scm
@@ -0,0 +1,273 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2021 Pierre Langlois <pierre.langlois@gmx.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu packages wasm)
+  #:use-module (guix gexp)
+  #:use-module (guix packages)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix download)
+  #:use-module (guix git-download)
+  #:use-module (guix utils)
+  #:use-module (guix build-system cmake)
+  #:use-module (guix build-system gnu)
+  #:use-module (guix build-system trivial)
+  #:use-module (gnu packages base)
+  #:use-module (gnu packages bash)
+  #:use-module (gnu packages compression)
+  #:use-module (gnu packages llvm)
+  #:use-module (gnu packages python))
+
+(define-public wasi-libc
+  (let ((commit "ad5133410f66b93a2381db5b542aad5e0964db96")
+        (revision "1"))
+    (package
+      (name "wasi-libc")
+      (version (git-version "0.1-alpha" revision commit))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                      (url "https://github.com/WebAssembly/wasi-libc")
+                      (commit commit)
+                      (recursive? #t)))
+                (file-name (git-file-name name version))
+                (sha256
+                 (base32
+                  "146jamq2q24vxjfpcwlqj84wzc80cbpbg0ns2wimyvzbanah48j6"))))
+      (build-system gnu-build-system)
+      (native-inputs (list clang-13))
+      (arguments
+       (list #:tests? #f ;No test suite
+             #:phases
+             #~(modify-phases %standard-phases
+                 (delete 'configure)
+                 (add-before 'build 'set-sysroot-include
+                   (lambda _
+                     (setenv "C_INCLUDE_PATH"
+                             (string-append (getcwd) "/sysroot/include"))))
+                 (add-before 'install 'set-install-dir
+                   (lambda _
+                     (setenv "INSTALL_DIR"
+                             (string-append #$output "/wasm32-wasi")))))))
+      (home-page "https://wasi.dev")
+      (synopsis "WASI libc implementation for WebAssembly")
+      (description
+       "WASI Libc is a libc for WebAssembly programs built on top of WASI
+system calls.  It provides a wide array of POSIX-compatible C APIs, including
+support for standard I/O, file I/O, filesystem manipulation, memory
+management, time, string, environment variables, program startup, and many
+other APIs.")
+      (license (list
+                ;; For wasi-libc, with LLVM exceptions
+                license:asl2.0
+                ;; For malloc.c.
+                license:cc0
+                ;; For cloudlibc.
+                license:bsd-2
+                ;; For wasi-libc and musl-libc.
+                license:expat)))))
+
+(define-public wasm32-wasi-clang-runtime
+  (package (inherit clang-runtime-13)
+    (native-inputs
+     (list clang-13 wasi-libc))
+    (inputs (list llvm-13))
+    (arguments
+     (list
+      #:build-type "Release"
+      #:tests? #f
+      ;; Stripping binaries breaks wasm linking, resulting in the following
+      ;; error: "archive has no index; run ranlib to add one".
+      #:strip-binaries? #f
+      #:configure-flags
+      #~(list "-DCMAKE_C_COMPILER=clang"
+              "-DCMAKE_C_COMPILER_TARGET=wasm32-wasi"
+              (string-append
+               "-DCMAKE_SYSROOT=" #$wasi-libc "/wasm32-wasi")
+              (string-append
+               "-DCMAKE_C_FLAGS=-I " #$wasi-libc "/wasm32-wasi/include")
+
+              "-DCOMPILER_RT_OS_DIR=wasi"
+
+              "-DCOMPILER_RT_BAREMETAL_BUILD=On"
+              "-DCOMPILER_RT_DEFAULT_TARGET_ONLY=On"
+
+              ;; WASM only needs libclang_rt.builtins-wasm32.a from
+              ;; compiler-rt.
+              (string-append "../compiler-rt-"
+                             #$(package-version clang-runtime-13)
+                             ".src/lib/builtins"))))))
+
+;; FIXME: Ideally we wouldn't need to build a separate compiler because clang
+;; can support multiple targets at runtime.  However Guix patches the default
+;; clang with a specific clang-runtime package.  It would be good to improve
+;; upstream Guix's support for cross-compiling with clang.
+
+(define clang-from-llvm (@@ (gnu packages llvm) clang-from-llvm))
+
+(define-public wasm32-wasi-clang
+  (let ((base (clang-from-llvm llvm-13 wasm32-wasi-clang-runtime
+                               "1j8pr5kk8iqyb4jds3yl7c6x672617h4ngkpl4575j7mk4nrwykq")))
+    (package (inherit base)
+      (name "wasm32-wasi-clang")
+      (inputs
+       (modify-inputs (package-inputs base)
+         (prepend wasi-libc)))
+      (arguments
+       (substitute-keyword-arguments (package-arguments base)
+         ((#:configure-flags flags)
+          #~(list "-DCLANG_INCLUDE_TESTS=True"
+                  ;; Use a sane default include directory.
+                  (string-append "-DC_INCLUDE_DIRS="
+                                 #$wasi-libc
+                                 "/wasm32-wasi/include")))
+         ((#:phases phases)
+          `(modify-phases ,phases
+             (delete 'symlink-cfi_ignorelist))))))))
+
+(define-public wasm32-wasi-libcxx
+  (package
+    (name "wasm32-wasi-libcxx")
+    (version "13.0.0")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/llvm/llvm-project")
+             (commit (string-append "llvmorg-" version))))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32
+         "0cjl0vssi4y2g4nfr710fb6cdhxmn5r0vis15sf088zsc5zydfhw"))))
+    (build-system cmake-build-system)
+    (arguments
+     (list
+      #:configure-flags
+      #~(list (string-append "-S ../source/runtimes")
+
+              "-DLLVM_ENABLE_RUNTIMES=libcxx;libcxxabi"
+
+              (string-append
+               "-DCMAKE_SYSROOT=" #$wasi-libc "/wasm32-wasi")
+
+              (string-append
+               "-DCMAKE_INCLUDE_PATH=" #$wasi-libc "/wasm32-wasi/include")
+
+              (string-append
+               "-DCMAKE_STAGING_PREFIX=" #$output "/wasm32-wasi")
+
+              "-DCMAKE_C_COMPILER=clang"
+              "-DCMAKE_C_COMPILER_WORKS=ON"
+              "-DCMAKE_CXX_COMPILER=clang++"
+              "-DCMAKE_CXX_COMPILER_WORKS=ON"
+              "-DCMAKE_C_COMPILER_TARGET=wasm32-wasi"
+              "-DCMAKE_CXX_COMPILER_TARGET=wasm32-wasi"
+
+              "-DLIBCXX_LIBDIR_SUFFIX=/wasm32-wasi"
+
+              "-DLIBCXX_ENABLE_EXCEPTIONS=OFF"
+              "-DLIBCXX_ENABLE_SHARED=OFF"
+              "-DLIBCXX_ENABLE_THREADS=OFF"
+              "-DLIBCXX_ENABLE_FILESYSTEM=OFF"
+
+              "-DLIBCXXABI_LIBDIR_SUFFIX=/wasm32-wasi"
+
+              "-DLIBCXXABI_ENABLE_EXCEPTIONS=OFF"
+              "-DLIBCXXABI_ENABLE_SHARED=OFF"
+              "-DLIBCXXABI_ENABLE_THREADS=OFF"
+              "-DLIBCXXABI_ENABLE_FILESYSTEM=OFF")
+      #:tests? #f
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-after 'set-paths 'adjust-CPLUS_INCLUDE_PATH
+            (lambda _
+              (setenv "CPLUS_INCLUDE_PATH"
+                      (string-append #$wasi-libc "/wasm32-wasi/include:"
+                                     (getenv "CPLUS_INCLUDE_PATH"))))))))
+    (native-inputs
+     (list wasm32-wasi-clang lld python))
+    (inputs
+     (list wasi-libc))
+    (home-page "https://libcxx.llvm.org")
+    (synopsis "C++ standard library, for WebAssembly")
+    (description
+     "This package provides an implementation of the C++ standard library for
+use with Clang, targeting C++11, C++14 and above.  This package targets
+WebAssembly with WASI.")
+    (license license:expat)))
+
+(define-public wasm32-wasi-clang-toolchain
+  (package
+    (name "wasm32-wasi-clang-toolchain")
+    (version (package-version wasm32-wasi-clang))
+    (source #f)
+    (build-system trivial-build-system)
+    (arguments
+     (list
+      #:builder
+      (with-imported-modules '((guix build union)
+                               (guix build utils))
+        #~(begin
+            (use-modules (guix build union)
+                         (guix build utils))
+            (union-build #$output
+                         (list #$wasm32-wasi-clang-runtime
+                               #$wasi-libc
+                               #$wasm32-wasi-libcxx))
+            (mkdir-p (string-append #$output "/bin"))
+
+            ;; We provide clang and clang++ via a wrapped program that sets
+            ;; include paths correctly so that it does not include paths from
+            ;; the host.
+
+            ;; FIXME: Review how we can provide better support for
+            ;; cross-compiling with clang in Guix, maybe adding support for
+            ;; the CROSS_C_INCLUDE_PATH and CROSS_CPLUS_INCLUDE_PATH
+            ;; environment variables like GCC.
+
+            (for-each
+             (lambda (bin)
+               (symlink (string-append #$wasm32-wasi-clang bin)
+                        (string-append #$output bin))
+               (wrap-program (string-append #$output bin)
+                 #:sh (string-append #$bash-minimal "/bin/bash")
+                 `("C_INCLUDE_PATH" ":" =
+                   (,(string-append #$output "/wasm32-wasi/include")))
+                 `("CPLUS_INCLUDE_PATH" ":" =
+                   ;; Make sure inclure/c++/v1 comes first for #include_next
+                   ;; to work.
+                   (,(string-append #$output "/wasm32-wasi/include/c++/v1")
+                    ,(string-append #$output "/wasm32-wasi/include")))))
+             '("/bin/clang" "/bin/clang++"))
+
+            (symlink (string-append #$lld "/bin/wasm-ld")
+                     (string-append #$output "/bin/wasm-ld"))))))
+    (inputs
+     (list bash-minimal
+           lld
+           wasm32-wasi-clang
+           wasm32-wasi-clang-runtime
+           wasi-libc
+           wasm32-wasi-libcxx))
+    (license (cons
+              (package-license wasm32-wasi-clang)
+              (package-license wasi-libc)))
+    (home-page "https://clang.llvm.org")
+    (synopsis "Complete Clang toolchain for C/C++ development, for WebAssembly.")
+    (description "This package provides a complete Clang toolchain for C/C++
+development targeting WebAssembly with WASI.  This includes Clang, as well as
+libc, libc++ and wasm-ld.")))
-- 
2.34.0

