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How can I use a binary WASM file in Perl's Wasm::Wasmtime?

Time:04-15

I have the following code which run as expected on Perl

use Wasm::Wasmtime;
 
my $store = Wasm::Wasmtime::Store->new;
my $module = Wasm::Wasmtime::Module->new( $store->engine, wat => q{
  (module
   (func (export "add") (param i32 i32) (result i32)
     local.get 0
     local.get 1
     i32.add)
  )
});
 
my $instance = Wasm::Wasmtime::Instance->new($module, $store);
my $add = $instance->exports->add;
print $add->call(1,2), "\n";  # 3

but i have binary wasm file how can i point to it instead of WAT text , inside the ->new any idea?

CodePudding user response:

As Keith alluded in his comment, the trick is to just give a file argument rather than a wat one to Wasm::Wasmtime::Module->new. This snippet turns your provided WAT into a disk .wasm file, then loads and runs it. If you have the .wasm file already, then obviously you don't need to use the little wat2file function shown:

use Wasm::Wasmtime;

my $filename = 'myfile.wasm';

# this is just to make your WAT text into a disk WASM file, making this self-contained
# don't use it if you already have a .wasm file already!
my $wat = q{
  (module
   (func (export "add") (param i32 i32) (result i32)
     local.get 0
     local.get 1
     i32.add)
  )
};
wat2file($filename, $wat);

my $store = Wasm::Wasmtime::Store->new;
my $module = Wasm::Wasmtime::Module->new($store->engine, file => $filename);
my $instance = Wasm::Wasmtime::Instance->new($module, $store);
my $add = $instance->exports->add;
print $add->call(1,2), "\n";  # 3

sub wat2file {
  my ($filename, $wat) = @_;
  require Wasm::Wasmtime::Wat2Wasm;
  open my $fh, '>', $filename;
  print $fh Wasm::Wasmtime::Wat2Wasm::wat2wasm($wat);
}
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