387426e7f4
* cranelift: improve syscall error/oom handling in JIT module The JIT module has several places where it `expect`s or `panic`s on syscall or allocator errors. For example, `mmap` and `mprotect` can fail if Linux `vm.max_map_count` is not high enough, and some users may wish to handle this error rather than immediately crashing. This commit plumbs these errors upward as new `ModuleError` types, so that callers of jit module functions like `finalize_definitions` and `define_function` can handle them (or just `unwrap()`, as desired). * cranelift: Remove ModuleError::Syscall variant Syscall errors can just be folded into the generic Backend error, which is an anyhow::Error * cranelift-jit: return io::ErrorKind::OutOfMemory for alloc failure Just using `io::Error::last_os_error()` is not correct as global allocator impls are not required to set errno
94 lines
3.1 KiB
Rust
94 lines
3.1 KiB
Rust
use codegen::ir::UserFuncName;
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use cranelift::prelude::*;
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use cranelift_codegen::settings::{self, Configurable};
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use cranelift_jit::{JITBuilder, JITModule};
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use cranelift_module::{default_libcall_names, Linkage, Module};
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use std::mem;
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fn main() {
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let mut flag_builder = settings::builder();
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flag_builder.set("use_colocated_libcalls", "false").unwrap();
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// FIXME set back to true once the x64 backend supports it.
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flag_builder.set("is_pic", "false").unwrap();
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let isa_builder = cranelift_native::builder().unwrap_or_else(|msg| {
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panic!("host machine is not supported: {}", msg);
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});
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let isa = isa_builder
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.finish(settings::Flags::new(flag_builder))
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.unwrap();
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let mut module = JITModule::new(JITBuilder::with_isa(isa, default_libcall_names()));
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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 mut sig_a = module.make_signature();
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sig_a.params.push(AbiParam::new(types::I32));
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sig_a.returns.push(AbiParam::new(types::I32));
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let mut sig_b = module.make_signature();
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sig_b.returns.push(AbiParam::new(types::I32));
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let func_a = module
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.declare_function("a", Linkage::Local, &sig_a)
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.unwrap();
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let func_b = module
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.declare_function("b", Linkage::Local, &sig_b)
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.unwrap();
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ctx.func.signature = sig_a;
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ctx.func.name = UserFuncName::user(0, func_a.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 block = bcx.create_block();
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bcx.switch_to_block(block);
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bcx.append_block_params_for_function_params(block);
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let param = bcx.block_params(block)[0];
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let cst = bcx.ins().iconst(types::I32, 37);
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let add = bcx.ins().iadd(cst, param);
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bcx.ins().return_(&[add]);
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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.signature = sig_b;
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ctx.func.name = UserFuncName::user(0, func_b.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 block = bcx.create_block();
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bcx.switch_to_block(block);
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let local_func = module.declare_func_in_func(func_a, &mut bcx.func);
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let arg = bcx.ins().iconst(types::I32, 5);
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let call = bcx.ins().call(local_func, &[arg]);
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let value = {
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let results = bcx.inst_results(call);
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assert_eq!(results.len(), 1);
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results[0].clone()
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};
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bcx.ins().return_(&[value]);
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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_definitions().unwrap();
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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() -> u32>(code_b) };
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// Call it!
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let res = ptr_b();
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assert_eq!(res, 42);
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}
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