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|
//! Allocator shim
// Adapted from rustc
use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
use rustc_ast::expand::allocator::{
ALLOCATOR_METHODS, AllocatorKind, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE,
alloc_error_handler_name, default_fn_name, global_fn_name,
};
use rustc_codegen_ssa::base::allocator_kind_for_codegen;
use rustc_session::config::OomStrategy;
use rustc_symbol_mangling::mangle_internal_symbol;
use crate::prelude::*;
/// Returns whether an allocator shim was created
pub(crate) fn codegen(tcx: TyCtxt<'_>, module: &mut dyn Module) -> bool {
let Some(kind) = allocator_kind_for_codegen(tcx) else { return false };
codegen_inner(
tcx,
module,
kind,
tcx.alloc_error_handler_kind(()).unwrap(),
tcx.sess.opts.unstable_opts.oom,
);
true
}
fn codegen_inner(
tcx: TyCtxt<'_>,
module: &mut dyn Module,
kind: AllocatorKind,
alloc_error_handler_kind: AllocatorKind,
oom_strategy: OomStrategy,
) {
let usize_ty = module.target_config().pointer_type();
if kind == AllocatorKind::Default {
for method in ALLOCATOR_METHODS {
let mut arg_tys = Vec::with_capacity(method.inputs.len());
for input in method.inputs.iter() {
match input.ty {
AllocatorTy::Layout => {
arg_tys.push(usize_ty); // size
arg_tys.push(usize_ty); // align
}
AllocatorTy::Ptr => arg_tys.push(usize_ty),
AllocatorTy::Usize => arg_tys.push(usize_ty),
AllocatorTy::ResultPtr | AllocatorTy::Unit => panic!("invalid allocator arg"),
}
}
let output = match method.output {
AllocatorTy::ResultPtr => Some(usize_ty),
AllocatorTy::Unit => None,
AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => {
panic!("invalid allocator output")
}
};
let sig = Signature {
call_conv: module.target_config().default_call_conv,
params: arg_tys.iter().cloned().map(AbiParam::new).collect(),
returns: output.into_iter().map(AbiParam::new).collect(),
};
crate::common::create_wrapper_function(
module,
sig,
&mangle_internal_symbol(tcx, &global_fn_name(method.name)),
&mangle_internal_symbol(tcx, &default_fn_name(method.name)),
);
}
}
let sig = Signature {
call_conv: module.target_config().default_call_conv,
params: vec![AbiParam::new(usize_ty), AbiParam::new(usize_ty)],
returns: vec![],
};
crate::common::create_wrapper_function(
module,
sig,
&mangle_internal_symbol(tcx, "__rust_alloc_error_handler"),
&mangle_internal_symbol(tcx, alloc_error_handler_name(alloc_error_handler_kind)),
);
{
let sig = Signature {
call_conv: module.target_config().default_call_conv,
params: vec![],
returns: vec![AbiParam::new(types::I8)],
};
let func_id = module
.declare_function(
&mangle_internal_symbol(tcx, OomStrategy::SYMBOL),
Linkage::Export,
&sig,
)
.unwrap();
let mut ctx = Context::new();
ctx.func.signature = sig;
{
let mut func_ctx = FunctionBuilderContext::new();
let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
let block = bcx.create_block();
bcx.switch_to_block(block);
let value = bcx.ins().iconst(types::I8, oom_strategy.should_panic() as i64);
bcx.ins().return_(&[value]);
bcx.seal_all_blocks();
bcx.finalize();
}
module.define_function(func_id, &mut ctx).unwrap();
}
{
let sig = Signature {
call_conv: module.target_config().default_call_conv,
params: vec![],
returns: vec![],
};
let func_id = module
.declare_function(
&mangle_internal_symbol(tcx, NO_ALLOC_SHIM_IS_UNSTABLE),
Linkage::Export,
&sig,
)
.unwrap();
let mut ctx = Context::new();
ctx.func.signature = sig;
let mut func_ctx = FunctionBuilderContext::new();
let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
let block = bcx.create_block();
bcx.switch_to_block(block);
bcx.ins().return_(&[]);
bcx.seal_all_blocks();
bcx.finalize();
module.define_function(func_id, &mut ctx).unwrap();
}
}
|
