Hello WebAssembly! (MVP implementation)

.github/workflows/smoke.yml

@@ -46,6 +46,7 @@ jobs:
           - aarch64-darwin
           - arm-linux-gnueabihf
           - i386-linux-musl
+          - wasm32-unknown-wasi
           - x86_64-dragonfly
           - x86_64-freebsd
           - x86_64-netbsd
@@ -55,5 +56,9 @@ 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/std/string_spec.cr

@@ -2646,12 +2646,14 @@ 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/target.cr

@@ -96,6 +96,10 @@ class Crystal::Codegen::Target
     @environment.starts_with?("linux")
   end
 
+  def wasm?
+    @architecture.starts_with?("wasm")
+  end
+
   def bsd?
     freebsd? || netbsd? || openbsd? || dragonfly?
   end
@@ -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/crystal/system.cr

@@ -19,6 +19,9 @@ end
 {% elsif flag?(:win32) %}
   require "./system/win32/hostname"
   require "./system/win32/cpucount"
+{% elsif flag?(:wasm32) %}
+  require "./system/wasm/hostname"
+  require "./system/wasm/cpucount"
 {% else %}
   {% raise "No Crystal::System implementation available" %}
 {% end %}

src/crystal/system/dir.cr

@@ -51,7 +51,7 @@ module Crystal::System::Dir
   # def self.delete(path : String) : Nil
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:unix) || flag?(:wasm32) %}
   require "./unix/dir"
 {% elsif flag?(:win32) %}
   require "./win32/dir"

src/crystal/system/env.cr

@@ -12,8 +12,10 @@ module Crystal::System::Env
   # def self.each(&block : String, String ->)
 end
 
-{% if flag?(:win32) %}
+{% if flag?(:unix) || flag?(:wasm32) %}
+  require "./unix/env"
+{% elsif flag?(:win32) %}
   require "./win32/env"
 {% else %}
-  require "./unix/env"
+  {% raise "No implementation of Crystal::System::Env available" %}
 {% end %}

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?(:wasm32) %}
+  require "./wasm/event_loop"
+{% elsif flag?(:unix) %}
   require "./unix/event_loop_libevent"
 {% elsif flag?(:win32) %}
   require "./win32/event_loop_iocp"

src/crystal/system/fiber.cr

@@ -13,6 +13,8 @@ end
   require "./unix/fiber"
 {% elsif flag?(:win32) %}
   require "./win32/fiber"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/fiber"
 {% else %}
   {% raise "fiber not supported" %}
 {% end %}

src/crystal/system/file.cr

@@ -49,7 +49,7 @@ module Crystal::System::File
   # def file_descriptor_close
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:unix) || flag?(:wasm32) %}
   require "./unix/file"
 {% elsif flag?(:win32) %}
   require "./win32/file"

src/crystal/system/file_descriptor.cr

@@ -1,5 +1,9 @@
-{% if flag?(:win32) %}
+{% if flag?(:unix) %}
+  require "./unix/file_descriptor"
+{% elsif flag?(:win32) %}
   require "./win32/file_descriptor"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/file_descriptor"
 {% else %}
-  require "./unix/file_descriptor"
+  {% raise "No Crystal::System::FileDescriptor implementation available" %}
 {% end %}

src/crystal/system/file_info.cr

@@ -1,4 +1,4 @@
-{% if flag?(:unix) %}
+{% if flag?(:unix) || flag?(:wasm32) %}
   require "./unix/file_info"
 {% elsif flag?(:win32) %}
   require "./win32/file_info"

src/crystal/system/group.cr

@@ -1,5 +1,7 @@
 {% if flag?(:unix) %}
   require "./unix/group"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/group"
 {% else %}
   {% raise "No Crystal::System::Group implementation available" %}
 {% end %}

src/crystal/system/mime.cr

@@ -7,6 +7,8 @@ end
   require "./unix/mime"
 {% elsif flag?(:win32) %}
   require "./win32/mime"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/mime"
 {% else %}
   {% raise "No Crystal::System::Mime implementation available" %}
 {% end %}

src/crystal/system/process.cr

@@ -74,6 +74,8 @@ end
   require "./unix/process"
 {% elsif flag?(:win32) %}
   require "./win32/process"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/process"
 {% else %}
   {% raise "No Crystal::System::Process implementation available" %}
 {% end %}

src/crystal/system/random.cr

@@ -12,6 +12,8 @@ end
 
 {% if flag?(:linux) %}
   require "./unix/getrandom"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/getentropy"
 {% elsif flag?(:openbsd) || flag?(:netbsd) %}
   require "./unix/arc4random"
 {% elsif flag?(:unix) %}

src/crystal/system/socket.cr

@@ -76,7 +76,7 @@ module Crystal::System::Socket
   # private def system_tcp_keepalive_count=(val : Int)
 end
 
-{% if flag?(:unix) %}
+{% if flag?(:unix) || flag?(:wasm32) %}
   require "./unix/socket"
 {% else %}
   {% raise "No Crystal::System::Socket implementation available" %}

src/crystal/system/thread.cr

@@ -33,6 +33,8 @@ require "./thread_linked_list"
   require "./unix/pthread_condition_variable"
 {% elsif flag?(:win32) %}
   require "./win32/thread"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/thread"
 {% else %}
   {% raise "thread not supported" %}
 {% end %}

src/crystal/system/thread_mutex.cr

@@ -21,6 +21,8 @@ end
   require "./unix/pthread_mutex"
 {% elsif flag?(:win32) %}
   require "./win32/thread_mutex"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/thread_mutex"
 {% else %}
   {% raise "thread not supported" %}
 {% end %}

src/crystal/system/time.cr

@@ -12,8 +12,10 @@ module Crystal::System::Time
   # def self.load_localtime : ::Time::Location?
 end
 
-{% if flag?(:win32) %}
+{% if flag?(:unix) || flag?(:wasm32) %}
+  require "./unix/time"
+{% elsif flag?(:win32) %}
   require "./win32/time"
 {% else %}
-  require "./unix/time"
+  {% raise "No implementation of Crystal::System::Time available" %}
 {% end %}

src/crystal/system/user.cr

@@ -1,5 +1,7 @@
 {% if flag?(:unix) %}
   require "./unix/user"
+{% elsif flag?(:wasm32) %}
+  require "./wasm/user"
 {% else %}
   {% raise "No Crystal::System::User implementation available" %}
 {% end %}

src/crystal/system/wasm/cpucount.cr

@@ -0,0 +1,5 @@
+module Crystal::System
+  def self.cpu_count
+    1
+  end
+end

src/crystal/system/wasm/event_loop.cr

@@ -0,0 +1,40 @@
+# :nodoc:
+module Crystal::EventLoop
+  # Runs the event loop.
+  def self.run_once
+  end
+
+  # Create a new resume event for a fiber.
+  def self.create_resume_event(fiber : Fiber) : Crystal::Event
+    Crystal::Event.new
+  end
+
+  # Creates a timeout_event.
+  def self.create_timeout_event(fiber) : Crystal::Event
+    Crystal::Event.new
+  end
+
+  # Creates a write event for a file descriptor.
+  def self.create_fd_write_event(io : IO::Evented, edge_triggered : Bool = false) : Crystal::Event
+    Crystal::Event.new
+  end
+
+  # Creates a read event for a file descriptor.
+  def self.create_fd_read_event(io : IO::Evented, edge_triggered : Bool = false) : Crystal::Event
+    Crystal::Event.new
+  end
+end
+
+struct Crystal::Event
+  def add(timeout : LibC::Timeval? = nil)
+  end
+
+  def add(timeout : Time::Span)
+  end
+
+  def free
+  end
+
+  def delete
+  end
+end

src/crystal/system/wasm/fiber.cr

@@ -0,0 +1,10 @@
+require "c/sys/mman"
+
+module Crystal::System::Fiber
+  def self.allocate_stack(stack_size) : Void*
+    raise RuntimeError.new("Cannot allocate new fiber stack")
+  end
+
+  def self.free_stack(stack : Void*, stack_size) : Nil
+  end
+end

src/crystal/system/wasm/file_descriptor.cr

@@ -0,0 +1,8 @@
+require "../unix/file_descriptor"
+
+# :nodoc:
+module Crystal::System::FileDescriptor
+  def self.from_stdio(fd)
+    return IO::FileDescriptor.new(fd).tap(&.flush_on_newline=(true))
+  end
+end

src/crystal/system/wasm/getentropy.cr

@@ -0,0 +1,72 @@
+require "c/unistd"
+
+lib LibC
+  fun getentropy(buffer : Void*, len : SizeT) : Int
+end
+
+module Crystal::System::Random
+  @@initialized = false
+  @@getentropy_available = false
+  @@urandom : ::File?
+
+  private def self.init
+    @@initialized = true
+
+    if LibC.getentropy(Bytes.new(16), 16) >= 0
+      @@getentropy_available = true
+    else
+      urandom = ::File.open("/dev/urandom", "r")
+      return unless urandom.info.type.character_device?
+
+      urandom.close_on_exec = true
+      urandom.sync = true # don't buffer bytes
+      @@urandom = urandom
+    end
+  end
+
+  # Reads n random bytes using the Linux `getentropy(2)` syscall.
+  def self.random_bytes(buf : Bytes) : Nil
+    init unless @@initialized
+
+    if @@getentropy_available
+      getentropy(buf)
+    elsif urandom = @@urandom
+      urandom.read_fully(buf)
+    else
+      raise "Failed to access secure source to generate random bytes!"
+    end
+  end
+
+  def self.next_u : UInt8
+    init unless @@initialized
+
+    if @@getentropy_available
+      buf = uninitialized UInt8[1]
+      getentropy(buf.to_slice)
+      buf.unsafe_as(UInt8)
+    elsif urandom = @@urandom
+      urandom.read_byte.not_nil!
+    else
+      raise "Failed to access secure source to generate random bytes!"
+    end
+  end
+
+  # Reads n random bytes using the Linux `getentropy(2)` syscall.
+  private def self.getentropy(buf)
+    # getentropy(2) may only read up to 256 bytes at once without being
+    # interrupted or returning early
+    chunk_size = 256
+
+    while buf.size > 0
+      if buf.size < chunk_size
+        chunk_size = buf.size
+      end
+
+      ret = LibC.getentropy(buf, chunk_size)
+
+      raise RuntimeError.from_errno("getentropy") if ret == -1
+
+      buf += chunk_size
+    end
+  end
+end

src/crystal/system/wasm/group.cr

@@ -0,0 +1,9 @@
+module Crystal::System::Group
+  private def from_name?(groupname : String)
+    nil
+  end
+
+  private def from_id?(groupid : String)
+    nil
+  end
+end

src/crystal/system/wasm/hostname.cr

@@ -0,0 +1,5 @@
+module Crystal::System
+  def self.hostname
+    ""
+  end
+end

src/crystal/system/wasm/mime.cr

@@ -0,0 +1,4 @@
+module Crystal::System::MIME
+  def self.load
+  end
+end