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cranelift: Add stack support to the interpreter with virtual addresses (#3187)

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* cranelift: Add stack support to the interpreter

We also change the approach for heap loads and stores.

Previously we would use the offset as the address to the heap. However,
this approach does not allow using the load/store instructions to
read/write from both the heap and the stack.

This commit changes the addressing mechanism of the interpreter. We now
return the real addresses from the addressing instructions
(stack_addr/heap_addr), and instead check if the address passed into
the load/store instructions points to an area in the heap or the stack.

* cranelift: Add virtual addresses to cranelift interpreter

Adds a  Virtual Addressing scheme that was discussed as a better
alternative to returning the real addresses.

The virtual addresses are split into 4 regions (stack, heap, tables and
global values), and the address itself is composed of an `entry` field
and an `offset` field. In general the `entry` field corresponds to the
instance of the resource (e.g. table5 is entry 5) and the `offset` field
is a byte offset inside that entry.

There is one exception to this which is the stack, where due to only
having one stack, the whole address is an offset field.

The number of bits in entry vs offset fields is variable with respect to
the `region` and the address size (32bits vs 64bits). This is done
because with 32 bit addresses we would have to compromise on heap size,
or have a small number of global values / tables. With 64 bit addresses
we do not have to compromise on this, but we need to support 32 bit
addresses.

* cranelift: Remove interpreter trap codes

* cranelift: Calculate frame_offset when entering or exiting a frame

* cranelift: Add safe read/write interface to DataValue

* cranelift: DataValue write full 128bit slot for booleans

* cranelift: Use DataValue accessors for trampoline.
This commit is contained in:
Afonso Bordado
2021-08-24 17:29:11 +01:00
committed by GitHub
parent f4ff7c350a
commit 2776074dfc
13 changed files with 1094 additions and 157 deletions
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27
cranelift/interpreter/src/value.rs
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@@ -92,7 +92,7 @@ impl Display for ValueTypeClass {
}
}
#[derive(Debug)]
#[derive(Debug, Clone)]
pub enum ValueConversionKind {
/// Throw a [ValueError] if an exact conversion to [Type] is not possible; e.g. in `i32` to
/// `i16`, convert `0x00001234` to `0x1234`.
@@ -234,6 +234,7 @@ impl Value for DataValue {
ValueConversionKind::Exact(ty) => match (self, ty) {
// TODO a lot to do here: from bmask to ireduce to raw_bitcast...
(DataValue::I64(n), types::I32) => DataValue::I32(i32::try_from(n)?),
(DataValue::I64(n), types::I64) => DataValue::I64(n),
(DataValue::B(b), t) if t.is_bool() => DataValue::B(b),
(dv, _) => unimplemented!("conversion: {} -> {:?}", dv.ty(), kind),
},
@@ -273,14 +274,17 @@ impl Value for DataValue {
(types::I32, types::I64) => unimplemented!(),
_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
},
ValueConversionKind::ZeroExtend(ty) => match (self.ty(), ty) {
(types::I8, types::I16) => unimplemented!(),
(types::I8, types::I32) => unimplemented!(),
(types::I8, types::I64) => unimplemented!(),
(types::I16, types::I32) => unimplemented!(),
(types::I16, types::I64) => unimplemented!(),
(types::I32, types::I64) => unimplemented!(),
_ => unimplemented!("conversion: {} -> {:?}", self.ty(), kind),
ValueConversionKind::ZeroExtend(ty) => match (self, ty) {
(DataValue::I8(_), types::I16) => unimplemented!(),
(DataValue::I8(_), types::I32) => unimplemented!(),
(DataValue::I8(_), types::I64) => unimplemented!(),
(DataValue::I16(_), types::I32) => unimplemented!(),
(DataValue::I16(_), types::I64) => unimplemented!(),
(DataValue::U32(n), types::I64) => DataValue::U64(n as u64),
(DataValue::I32(n), types::I64) => DataValue::I64(n as u32 as i64),
(DataValue::U64(n), types::I64) => DataValue::U64(n),
(DataValue::I64(n), types::I64) => DataValue::I64(n),
(dv, _) => unimplemented!("conversion: {} -> {:?}", dv.ty(), kind),
},
ValueConversionKind::ToUnsigned => match self {
DataValue::I8(n) => DataValue::U8(n as u8),
@@ -340,7 +344,8 @@ impl Value for DataValue {
}
fn add(self, other: Self) -> ValueResult<Self> {
binary_match!(wrapping_add(&self, &other); [I8, I16, I32, I64, I128]) // TODO: floats must handle NaNs, +/-0
// TODO: floats must handle NaNs, +/-0
binary_match!(wrapping_add(&self, &other); [I8, I16, I32, I64, I128, U8, U16, U32, U64, U128])
}
fn sub(self, other: Self) -> ValueResult<Self> {
@@ -396,7 +401,7 @@ impl Value for DataValue {
}
fn and(self, other: Self) -> ValueResult<Self> {
binary_match!(&(&self, &other); [I8, I16, I32, I64])
binary_match!(&(&self, &other); [B, I8, I16, I32, I64])
}
fn or(self, other: Self) -> ValueResult<Self> {