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|
//! Defines [`Pointer`] which is used to improve the quality of the generated clif ir for pointer
//! operations.
use crate::prelude::*;
use rustc_target::abi::Align;
use cranelift_codegen::ir::immediates::Offset32;
/// A pointer pointing either to a certain address, a certain stack slot or nothing.
#[derive(Copy, Clone, Debug)]
pub(crate) struct Pointer {
base: PointerBase,
offset: Offset32,
}
#[derive(Copy, Clone, Debug)]
pub(crate) enum PointerBase {
Addr(Value),
Stack(StackSlot),
Dangling(Align),
}
impl Pointer {
pub(crate) fn new(addr: Value) -> Self {
Pointer { base: PointerBase::Addr(addr), offset: Offset32::new(0) }
}
pub(crate) fn stack_slot(stack_slot: StackSlot) -> Self {
Pointer { base: PointerBase::Stack(stack_slot), offset: Offset32::new(0) }
}
pub(crate) fn dangling(align: Align) -> Self {
Pointer { base: PointerBase::Dangling(align), offset: Offset32::new(0) }
}
pub(crate) fn debug_base_and_offset(self) -> (PointerBase, Offset32) {
(self.base, self.offset)
}
pub(crate) fn get_addr(self, fx: &mut FunctionCx<'_, '_, '_>) -> Value {
match self.base {
PointerBase::Addr(base_addr) => {
let offset: i64 = self.offset.into();
if offset == 0 { base_addr } else { fx.bcx.ins().iadd_imm(base_addr, offset) }
}
PointerBase::Stack(stack_slot) => {
fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, self.offset)
}
PointerBase::Dangling(align) => {
fx.bcx.ins().iconst(fx.pointer_type, i64::try_from(align.bytes()).unwrap())
}
}
}
pub(crate) fn offset(self, fx: &mut FunctionCx<'_, '_, '_>, extra_offset: Offset32) -> Self {
self.offset_i64(fx, extra_offset.into())
}
pub(crate) fn offset_i64(self, fx: &mut FunctionCx<'_, '_, '_>, extra_offset: i64) -> Self {
if let Some(new_offset) = self.offset.try_add_i64(extra_offset) {
Pointer { base: self.base, offset: new_offset }
} else {
let base_offset: i64 = self.offset.into();
if let Some(new_offset) = base_offset.checked_add(extra_offset) {
let base_addr = match self.base {
PointerBase::Addr(addr) => addr,
PointerBase::Stack(stack_slot) => {
fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0)
}
PointerBase::Dangling(align) => {
fx.bcx.ins().iconst(fx.pointer_type, i64::try_from(align.bytes()).unwrap())
}
};
let addr = fx.bcx.ins().iadd_imm(base_addr, new_offset);
Pointer { base: PointerBase::Addr(addr), offset: Offset32::new(0) }
} else {
panic!(
"self.offset ({}) + extra_offset ({}) not representable in i64",
base_offset, extra_offset
);
}
}
}
pub(crate) fn offset_value(self, fx: &mut FunctionCx<'_, '_, '_>, extra_offset: Value) -> Self {
match self.base {
PointerBase::Addr(addr) => Pointer {
base: PointerBase::Addr(fx.bcx.ins().iadd(addr, extra_offset)),
offset: self.offset,
},
PointerBase::Stack(stack_slot) => {
let base_addr = fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, self.offset);
Pointer {
base: PointerBase::Addr(fx.bcx.ins().iadd(base_addr, extra_offset)),
offset: Offset32::new(0),
}
}
PointerBase::Dangling(align) => {
let addr =
fx.bcx.ins().iconst(fx.pointer_type, i64::try_from(align.bytes()).unwrap());
Pointer {
base: PointerBase::Addr(fx.bcx.ins().iadd(addr, extra_offset)),
offset: self.offset,
}
}
}
}
pub(crate) fn load(self, fx: &mut FunctionCx<'_, '_, '_>, ty: Type, flags: MemFlags) -> Value {
match self.base {
PointerBase::Addr(base_addr) => fx.bcx.ins().load(ty, flags, base_addr, self.offset),
PointerBase::Stack(stack_slot) => fx.bcx.ins().stack_load(ty, stack_slot, self.offset),
PointerBase::Dangling(_align) => unreachable!(),
}
}
pub(crate) fn store(self, fx: &mut FunctionCx<'_, '_, '_>, value: Value, flags: MemFlags) {
match self.base {
PointerBase::Addr(base_addr) => {
fx.bcx.ins().store(flags, value, base_addr, self.offset);
}
PointerBase::Stack(stack_slot) => {
fx.bcx.ins().stack_store(value, stack_slot, self.offset);
}
PointerBase::Dangling(_align) => unreachable!(),
}
}
}
|
