Hello WebAssembly! (MVP implementation)

.github/workflows/smoke.yml

@@ -45,8 +45,9 @@ jobs:
         target:
           - aarch64-darwin
           - arm-linux-gnueabihf
-          - i386-linux-musl
           - i386-linux-gnu
+          - i386-linux-musl
+          - wasm32-unknown-wasi
           - x86_64-dragonfly
           - x86_64-freebsd
           - x86_64-netbsd
@@ -56,5 +57,9 @@ jobs:
       - name: Download Crystal source
         uses: actions/checkout@v2
 
+      - name: Make compiler (special case only for wasm32, until next release).
+        if: ${{ matrix.target == 'wasm32-unknown-wasi' }}
+        run: bin/ci with_build_env make
+
       - name: Run smoke test
         run: bin/ci with_build_env make smoke_test target=${{ matrix.target }}

spec/compiler/ffi/ffi_spec.cr

@@ -1,4 +1,4 @@
-{% skip_file if !flag?(:unix) || flag?(:without_ffi) %}
+{% skip_file if !flag?(:unix) || flag?(:without_ffi) || flag?(:wasm32) %}
 
 require "../spec_helper"
 require "compiler/crystal/ffi"

spec/compiler/loader/unix_spec.cr

@@ -1,4 +1,4 @@
-{% skip_file unless flag?(:unix) %}
+{% skip_file if !flag?(:unix) || flag?(:wasm32) %}
 
 require "./spec_helper"
 require "../spec_helper"

spec/std/process_spec.cr

@@ -1,3 +1,5 @@
+{% skip_file if flag?(:wasm32) %}
+
 require "spec"
 require "process"
 require "./spec_helper"

spec/std/signal_spec.cr

@@ -1,3 +1,5 @@
+{% skip_file if flag?(:wasm32) %}
+
 require "spec"
 require "signal"
 

spec/std/socket/addrinfo_spec.cr

@@ -74,8 +74,8 @@ describe Socket::Addrinfo, tags: "network" do
   end
 
   describe "Error" do
-    {% unless flag?(:win32) %}
-      # This method is not available on windows because windows support was introduced after deprecation.
+    {% unless flag?(:win32) || flag?(:wasm32) %}
+      # This method is not available on windows/wasm because windows/wasm support was introduced after deprecation.
       it ".new (deprecated)" do
         error = Socket::Addrinfo::Error.new(LibC::EAI_NONAME, "No address found", "foobar.com")
         error.os_error.should eq Errno.new(LibC::EAI_NONAME)

spec/std/socket/tcp_server_spec.cr

@@ -1,3 +1,5 @@
+{% skip_file if flag?(:wasm32) %}
+
 require "./spec_helper"
 require "../../support/win32"
 

spec/std/socket/tcp_socket_spec.cr

@@ -1,3 +1,5 @@
+{% skip_file if flag?(:wasm32) %}
+
 require "./spec_helper"
 require "../../support/win32"
 

spec/std/string_spec.cr

@@ -2719,12 +2719,14 @@ describe "String" do
     string.should be(clone)
   end
 
-  it "allocates buffer of correct size when UInt8 is given to new (#3332)" do
-    String.new(255_u8) do |buffer|
-      LibGC.size(buffer).should be >= 255
-      {255, 0}
+  {% unless flag?(:wasm32) %}
+    it "allocates buffer of correct size when UInt8 is given to new (#3332)" do
+      String.new(255_u8) do |buffer|
+        LibGC.size(buffer).should be >= 255
+        {255, 0}
+      end
     end
-  end
+  {% end %}
 
   it "raises on String.new if returned bytesize is greater than capacity" do
     expect_raises ArgumentError, "Bytesize out of capacity bounds" do

src/compiler/crystal/codegen/link.cr

@@ -100,7 +100,11 @@ module Crystal
 
   class Program
     def object_extension
-      has_flag?("windows") ? ".obj" : ".o"
+      case
+      when has_flag?("windows") then ".obj"
+      when has_flag?("wasm32")  then ".wasm"
+      else                           ".o"
+      end
     end
 
     def lib_flags

src/compiler/crystal/codegen/target.cr

@@ -96,12 +96,16 @@ class Crystal::Codegen::Target
     @environment.starts_with?("linux")
   end
 
+  def wasi?
+    @environment.starts_with?("wasi")
+  end
+
   def bsd?
     freebsd? || netbsd? || openbsd? || dragonfly?
   end
 
   def unix?
-    macos? || bsd? || linux?
+    macos? || bsd? || linux? || wasi?
   end
 
   def gnu?
@@ -144,6 +148,8 @@ class Crystal::Codegen::Target
       if cpu.empty? && !features.includes?("fp") && armhf?
         features += "+vfp2"
       end
+    when "wasm32"
+      LLVM.init_webassembly
     else
       raise Target::Error.new("Unsupported architecture for target triple: #{self}")
     end

src/compiler/crystal/command.cr

@@ -247,7 +247,7 @@ class Crystal::Command
       begin
         elapsed = Time.measure do
           Process.run(output_filename, args: run_args, input: Process::Redirect::Inherit, output: Process::Redirect::Inherit, error: Process::Redirect::Inherit) do |process|
-            {% unless flag?(:win32) %}
+            {% unless flag?(:win32) || flag?(:wasm32) %}
               # Ignore the signal so we don't exit the running process
               # (the running process can still handle this signal)
               ::Signal::INT.ignore # do

src/compiler/crystal/compiler.cr

@@ -394,6 +394,9 @@ module Crystal
         end
 
         {cmd, nil}
+      elsif program.has_flag? "wasm32"
+        link_flags = @link_flags || ""
+        { %(wasm-ld "${@}" -o #{Process.quote_posix(output_filename)} #{link_flags} -lc #{program.lib_flags}), object_names }
       else
         link_flags = @link_flags || ""
         link_flags += " -rdynamic"

src/crystal/system.cr

@@ -8,7 +8,10 @@ module Crystal::System
   # def self.cpu_count
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./system/wasi/hostname"
+  require "./system/wasi/cpucount"
+{% elsif flag?(:unix) %}
   require "./system/unix/hostname"
 
   {% if flag?(:bsd) %}

src/crystal/system/dir.cr

@@ -51,7 +51,9 @@ module Crystal::System::Dir
   # def self.delete(path : String) : Nil
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/dir"
+{% elsif flag?(:unix) %}
   require "./unix/dir"
 {% elsif flag?(:win32) %}
   require "./win32/dir"

src/crystal/system/event_loop.cr

@@ -28,7 +28,9 @@ struct Crystal::Event
   # def add(time_span : Time::Span?) : Nil
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/event_loop"
+{% elsif flag?(:unix) %}
   require "./unix/event_loop_libevent"
 {% elsif flag?(:win32) %}
   require "./win32/event_loop_iocp"

src/crystal/system/fiber.cr

@@ -9,7 +9,9 @@ module Crystal::System::Fiber
   # def self.main_fiber_stack(stack_bottom : Void*) : Void*
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/fiber"
+{% elsif flag?(:unix) %}
   require "./unix/fiber"
 {% elsif flag?(:win32) %}
   require "./win32/fiber"

src/crystal/system/file.cr

@@ -49,7 +49,9 @@ module Crystal::System::File
   # def file_descriptor_close
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/file"
+{% elsif flag?(:unix) %}
   require "./unix/file"
 {% elsif flag?(:win32) %}
   require "./win32/file"

src/crystal/system/file_descriptor.cr

@@ -1,4 +1,6 @@
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/file_descriptor"
+{% elsif flag?(:unix) %}
   require "./unix/file_descriptor"
 {% elsif flag?(:win32) %}
   require "./win32/file_descriptor"

src/crystal/system/group.cr

@@ -1,4 +1,6 @@
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/group"
+{% elsif flag?(:unix) %}
   require "./unix/group"
 {% else %}
   {% raise "No Crystal::System::Group implementation available" %}

src/crystal/system/path.cr

@@ -3,7 +3,9 @@ module Crystal::System::Path
   # def self.home : String
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/path"
+{% elsif flag?(:unix) %}
   require "./unix/path"
 {% elsif flag?(:win32) %}
   require "./win32/path"

src/crystal/system/process.cr

@@ -70,7 +70,9 @@ module Crystal::System
   ORIGINAL_STDERR = IO::FileDescriptor.new(2, blocking: true)
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/process"
+{% elsif flag?(:unix) %}
   require "./unix/process"
 {% elsif flag?(:win32) %}
   require "./win32/process"

src/crystal/system/random.cr

@@ -10,7 +10,9 @@ module Crystal::System::Random
   # def self.next_u
 end
 
-{% if flag?(:linux) %}
+{% if flag?(:wasi) %}
+  require "./wasi/random"
+{% elsif flag?(:linux) %}
   require "./unix/getrandom"
 {% elsif flag?(:openbsd) || flag?(:netbsd) %}
   require "./unix/arc4random"

src/crystal/system/socket.cr

@@ -76,7 +76,9 @@ module Crystal::System::Socket
   # private def system_tcp_keepalive_count=(val : Int)
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/socket"
+{% elsif flag?(:unix) %}
   require "./unix/socket"
 {% elsif flag?(:win32) %}
   require "./win32/socket"

src/crystal/system/thread.cr

@@ -28,7 +28,9 @@ end
 
 require "./thread_linked_list"
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/thread"
+{% elsif flag?(:unix) %}
   require "./unix/pthread"
   require "./unix/pthread_condition_variable"
 {% elsif flag?(:win32) %}

src/crystal/system/thread_mutex.cr

@@ -17,7 +17,9 @@ class Thread
   end
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/thread_mutex"
+{% elsif flag?(:unix) %}
   require "./unix/pthread_mutex"
 {% elsif flag?(:win32) %}
   require "./win32/thread_mutex"

src/crystal/system/user.cr

@@ -1,4 +1,6 @@
-{% if flag?(:unix) %}
+{% if flag?(:wasi) %}
+  require "./wasi/user"
+{% elsif flag?(:unix) %}
   require "./unix/user"
 {% else %}
   {% raise "No Crystal::System::User implementation available" %}

src/crystal/system/wasi/cpucount.cr

@@ -0,0 +1,6 @@
+module Crystal::System
+  def self.cpu_count
+    # TODO: There isn't a good way to get the number of CPUs on WebAssembly
+    1
+  end
+end