Files
wasmtime/lib/simplejit/examples/simplejit-minimal.rs
Dan Gohman 91477d21c8 Add an as_u32() member to entity_impl types.
This allows us to avoid a lot of casting indices back to u32.
2018-12-11 15:40:24 -05:00

83 lines
2.6 KiB
Rust

extern crate cranelift;
extern crate cranelift_module;
extern crate cranelift_simplejit;
use cranelift::prelude::*;
use cranelift_module::{Linkage, Module};
use cranelift_simplejit::{SimpleJITBackend, SimpleJITBuilder};
use std::mem;
fn main() {
let mut module: Module<SimpleJITBackend> = Module::new(SimpleJITBuilder::new());
let mut ctx = module.make_context();
let mut func_ctx = FunctionBuilderContext::new();
let mut sig_a = module.make_signature();
sig_a.params.push(AbiParam::new(types::I32));
sig_a.returns.push(AbiParam::new(types::I32));
let mut sig_b = module.make_signature();
sig_b.returns.push(AbiParam::new(types::I32));
let func_a = module
.declare_function("a", Linkage::Local, &sig_a)
.unwrap();
let func_b = module
.declare_function("b", Linkage::Local, &sig_b)
.unwrap();
ctx.func.signature = sig_a;
ctx.func.name = ExternalName::user(0, func_a.as_u32());
{
let mut bcx: FunctionBuilder = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
let ebb = bcx.create_ebb();
bcx.switch_to_block(ebb);
bcx.append_ebb_params_for_function_params(ebb);
let param = bcx.ebb_params(ebb)[0];
let cst = bcx.ins().iconst(types::I32, 37);
let add = bcx.ins().iadd(cst, param);
bcx.ins().return_(&[add]);
bcx.seal_all_blocks();
bcx.finalize();
}
module.define_function(func_a, &mut ctx).unwrap();
module.clear_context(&mut ctx);
ctx.func.signature = sig_b;
ctx.func.name = ExternalName::user(0, func_b.as_u32());
{
let mut bcx: FunctionBuilder = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
let ebb = bcx.create_ebb();
bcx.switch_to_block(ebb);
let local_func = module.declare_func_in_func(func_a, &mut bcx.func);
let arg = bcx.ins().iconst(types::I32, 5);
let call = bcx.ins().call(local_func, &[arg]);
let value = {
let results = bcx.inst_results(call);
assert_eq!(results.len(), 1);
results[0].clone()
};
bcx.ins().return_(&[value]);
bcx.seal_all_blocks();
bcx.finalize();
}
module.define_function(func_b, &mut ctx).unwrap();
module.clear_context(&mut ctx);
// Perform linking.
module.finalize_definitions();
// Get a raw pointer to the generated code.
let code_b = module.get_finalized_function(func_b);
// Cast it to a rust function pointer type.
let ptr_b = unsafe { mem::transmute::<_, fn() -> u32>(code_b) };
// Call it!
let res = ptr_b();
assert_eq!(res, 42);
}