;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2022-2023 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 base32)
  #:use-module (guix gexp)
  #:use-module (guix packages)
  #:use-module ((guix licenses) #:prefix license:)
  #:use-module (guix utils)
  #:use-module (guix git-download)
  #:use-module (guix build-system cmake)
  #:use-module (guix build-system gnu)
  #:use-module (guix build-system trivial)
  #:use-module (gnu packages bash)
  #:use-module (gnu packages llvm)
  #:use-module (gnu packages python))

(define-public wasi-libc
  (package
    (name "wasi-libc")
    (version "sdk-19")
    (source
     (origin
       (method git-fetch)
       (uri (git-reference
             (url "https://github.com/WebAssembly/wasi-libc")
             (commit (string-append "wasi-" version))
             (recursive? #t)))
       (file-name (git-file-name name version))
       (sha256
        (base32 "0bnpz8wk9wiic938296gxp4vz820bvpi1w41jksjzz5552hql169"))))
    (build-system gnu-build-system)
    (native-inputs (list clang-15))
    (arguments
     (list
      #:tests? #f ;No test suite
      ;; Firefox uses wasm2c to compile WebAssembly to C code, and it
      ;; does not support the memory.copy opcode.
      ;; See https://bugzilla.mozilla.org/show_bug.cgi?id=1773200#c4
      #:make-flags ''("BULK_MEMORY_SOURCES=")
      #: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-15)
    (native-inputs
     (list clang-15
           wasi-libc))
    (inputs (list llvm-15))
    (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.
              "../source/compiler-rt/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 llvm-monorepo (@@ (gnu packages llvm) llvm-monorepo))

(define-public wasm32-wasi-clang
  (let ((base (clang-from-llvm llvm-15 wasm32-wasi-clang-runtime)))
    (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 (package-version llvm-15))
    (source
     (llvm-monorepo version))
    (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 lld python wasm32-wasi-clang))
    (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
                  wasi-libc
                  wasm32-wasi-clang
                  wasm32-wasi-clang-runtime
                  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.")))