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Eval const values

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This commit is contained in:
bjorn3 2018-07-21 18:44:34 +02:00
parent 4fad0f714f
commit e40d025843
2 changed files with 28 additions and 8 deletions
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6
example.rs
View File

@ -170,3 +170,9 @@ fn use_size_of() -> usize {
let copy2 = &copy::<u8>;
copy2(src, dst, 1);
}*/
const Abc: u8 = 6 * 7;
fn use_const() -> u8 {
Abc
}

30
src/constant.rs
View File

@ -1,11 +1,11 @@
use prelude::*;
use rustc::mir::interpret::{GlobalId, AllocId, read_target_uint};
use rustc::mir::interpret::{ConstValue, GlobalId, AllocId, read_target_uint};
use rustc_mir::interpret::{CompileTimeEvaluator, Memory, MemoryKind};
use cranelift_module::*;
pub fn trans_constant<'a, 'tcx: 'a>(fx: &mut FunctionCx<'a, 'tcx>, const_: &Constant<'tcx>) -> CValue<'tcx> {
let value = match const_.literal {
Literal::Value { value } => value,
let const_val = match const_.literal {
Literal::Value { value } => fx.monomorphize(&value),
Literal::Promoted { index } => fx
.tcx
.const_eval(ParamEnv::reveal_all().and(GlobalId {
@ -14,21 +14,35 @@ pub fn trans_constant<'a, 'tcx: 'a>(fx: &mut FunctionCx<'a, 'tcx>, const_: &Cons
}))
.unwrap(),
};
fx.tcx.sess.warn(&format!("const: {:?}", value));
let const_ = match const_val.val {
ConstValue::Unevaluated(def_id, ref substs) => {
let param_env = ParamEnv::reveal_all();
let instance = Instance::resolve(fx.tcx, param_env, def_id, substs).unwrap();
let cid = GlobalId {
instance,
promoted: None,
};
fx.tcx.const_eval(param_env.and(cid)).unwrap()
},
_ => const_val,
};
fx.tcx.sess.warn(&format!("const_val: {:?} const_: {:?}", const_val, const_));
let ty = fx.monomorphize(&const_.ty);
let layout = fx.layout_of(ty);
match ty.sty {
TypeVariants::TyBool => {
let bits = value.to_scalar().unwrap().to_bits(layout.size).unwrap();
let bits = const_.val.to_bits(layout.size).unwrap();
CValue::const_val(fx, ty, bits as u64 as i64)
}
TypeVariants::TyUint(_) => {
let bits = value.to_scalar().unwrap().to_bits(layout.size).unwrap();
let bits = const_.val.to_bits(layout.size).unwrap();
CValue::const_val(fx, ty, bits as u64 as i64)
}
TypeVariants::TyInt(_) => {
let bits = value.to_scalar().unwrap().to_bits(layout.size).unwrap();
let bits = const_.val.to_bits(layout.size).unwrap();
CValue::const_val(fx, ty, bits as i128 as i64)
}
TypeVariants::TyFnDef(def_id, substs) => {
@ -42,7 +56,7 @@ pub fn trans_constant<'a, 'tcx: 'a>(fx: &mut FunctionCx<'a, 'tcx>, const_: &Cons
return CValue::ByRef(fx.bcx.ins().iconst(types::I64, 0), layout);
}
let mut memory = Memory::<CompileTimeEvaluator>::new(fx.tcx.at(DUMMY_SP), ());
let alloc = fx.tcx.const_value_to_allocation(value);
let alloc = fx.tcx.const_value_to_allocation(const_);
//println!("const value: {:?} allocation: {:?}", value, alloc);
let alloc_id = memory.allocate_value(alloc.clone(), MemoryKind::Stack).unwrap();
let data_id = get_global_for_alloc_id(fx, &memory, alloc_id);