d2943ec32d
This minimally demonstrates usage of the API, and serves as a very small testcase to test that the basic JIT mechanisms are working.
59 lines
1.8 KiB
Rust
59 lines
1.8 KiB
Rust
extern crate cranelift;
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extern crate cranelift_module;
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extern crate cranelift_simplejit;
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use cranelift::prelude::*;
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use cranelift_module::{Linkage, Module};
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use cranelift_simplejit::{SimpleJITBackend, SimpleJITBuilder};
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use std::mem;
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fn main() {
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let mut module: Module<SimpleJITBackend> = Module::new(SimpleJITBuilder::new());
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let mut ctx = module.make_context();
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let mut func_ctx = FunctionBuilderContext::new();
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let sig = module.make_signature();
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let func_a = module.declare_function("a", Linkage::Local, &sig).unwrap();
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let func_b = module.declare_function("b", Linkage::Local, &sig).unwrap();
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ctx.func.name = ExternalName::user(0, func_a.index() as u32);
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{
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let mut bcx: FunctionBuilder = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
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let ebb = bcx.create_ebb();
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bcx.switch_to_block(ebb);
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bcx.ins().return_(&[]);
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bcx.seal_all_blocks();
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bcx.finalize();
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}
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module.define_function(func_a, &mut ctx).unwrap();
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module.clear_context(&mut ctx);
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ctx.func.name = ExternalName::user(0, func_b.index() as u32);
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{
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let mut bcx: FunctionBuilder = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
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let ebb = bcx.create_ebb();
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bcx.switch_to_block(ebb);
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let local_func = module.declare_func_in_func(func_a, &mut bcx.func);
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bcx.ins().call(local_func, &[]);
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bcx.ins().return_(&[]);
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bcx.seal_all_blocks();
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bcx.finalize();
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}
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module.define_function(func_b, &mut ctx).unwrap();
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module.clear_context(&mut ctx);
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// Perform linking.
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module.finalize_all();
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// Get a raw pointer to the generated code.
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let code_b = module.get_finalized_function(func_b);
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// Cast it to a rust function pointer type.
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let ptr_b = unsafe { mem::transmute::<_, fn()>(code_b) };
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// Call it!
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ptr_b();
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}
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