6 use cranelift_codegen::binemit::{NullStackMapSink, NullTrapSink};
7 use rustc_ast::expand::allocator::{AllocatorKind, AllocatorTy, ALLOCATOR_METHODS};
9 /// Returns whether an allocator shim was created
10 pub(crate) fn codegen(
12 module: &mut impl Module,
13 unwind_context: &mut UnwindContext,
15 let any_dynamic_crate = tcx.dependency_formats(()).iter().any(|(_, list)| {
16 use rustc_middle::middle::dependency_format::Linkage;
17 list.iter().any(|&linkage| linkage == Linkage::Dynamic)
19 if any_dynamic_crate {
21 } else if let Some(kind) = tcx.allocator_kind(()) {
22 codegen_inner(module, unwind_context, kind, tcx.lang_items().oom().is_some());
30 module: &mut impl Module,
31 unwind_context: &mut UnwindContext,
33 has_alloc_error_handler: bool,
35 let usize_ty = module.target_config().pointer_type();
37 for method in ALLOCATOR_METHODS {
38 let mut arg_tys = Vec::with_capacity(method.inputs.len());
39 for ty in method.inputs.iter() {
41 AllocatorTy::Layout => {
42 arg_tys.push(usize_ty); // size
43 arg_tys.push(usize_ty); // align
45 AllocatorTy::Ptr => arg_tys.push(usize_ty),
46 AllocatorTy::Usize => arg_tys.push(usize_ty),
48 AllocatorTy::ResultPtr | AllocatorTy::Unit => panic!("invalid allocator arg"),
51 let output = match method.output {
52 AllocatorTy::ResultPtr => Some(usize_ty),
53 AllocatorTy::Unit => None,
55 AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
56 panic!("invalid allocator output")
61 call_conv: CallConv::triple_default(module.isa().triple()),
62 params: arg_tys.iter().cloned().map(AbiParam::new).collect(),
63 returns: output.into_iter().map(AbiParam::new).collect(),
66 let caller_name = format!("__rust_{}", method.name);
67 let callee_name = kind.fn_name(method.name);
69 let func_id = module.declare_function(&caller_name, Linkage::Export, &sig).unwrap();
71 let callee_func_id = module.declare_function(&callee_name, Linkage::Import, &sig).unwrap();
73 let mut ctx = Context::new();
74 ctx.func = Function::with_name_signature(ExternalName::user(0, 0), sig.clone());
76 let mut func_ctx = FunctionBuilderContext::new();
77 let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
79 let block = bcx.create_block();
80 bcx.switch_to_block(block);
83 .map(|ty| bcx.append_block_param(block, ty))
84 .collect::<Vec<Value>>();
86 let callee_func_ref = module.declare_func_in_func(callee_func_id, &mut bcx.func);
87 let call_inst = bcx.ins().call(callee_func_ref, &args);
88 let results = bcx.inst_results(call_inst).to_vec(); // Clone to prevent borrow error
90 bcx.ins().return_(&results);
91 bcx.seal_all_blocks();
95 .define_function(func_id, &mut ctx, &mut NullTrapSink {}, &mut NullStackMapSink {})
97 unwind_context.add_function(func_id, &ctx, module.isa());
100 let sig = Signature {
101 call_conv: CallConv::triple_default(module.isa().triple()),
102 params: vec![AbiParam::new(usize_ty), AbiParam::new(usize_ty)],
106 let callee_name = if has_alloc_error_handler { "__rg_oom" } else { "__rdl_oom" };
109 module.declare_function("__rust_alloc_error_handler", Linkage::Export, &sig).unwrap();
111 let callee_func_id = module.declare_function(callee_name, Linkage::Import, &sig).unwrap();
113 let mut ctx = Context::new();
114 ctx.func = Function::with_name_signature(ExternalName::user(0, 0), sig);
116 let mut func_ctx = FunctionBuilderContext::new();
117 let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
119 let block = bcx.create_block();
120 bcx.switch_to_block(block);
121 let args = (&[usize_ty, usize_ty])
123 .map(|&ty| bcx.append_block_param(block, ty))
124 .collect::<Vec<Value>>();
126 let callee_func_ref = module.declare_func_in_func(callee_func_id, &mut bcx.func);
127 bcx.ins().call(callee_func_ref, &args);
129 bcx.ins().trap(TrapCode::UnreachableCodeReached);
130 bcx.seal_all_blocks();
134 .define_function(func_id, &mut ctx, &mut NullTrapSink {}, &mut NullStackMapSink {})
136 unwind_context.add_function(func_id, &ctx, module.isa());