Refactor Instr and move definition to translator::utils submodule (#1541)

* replace {into,from}_u32 methods with From impls

* refactor Instr::{from,into}_usize

* update Instr docs

* move Instr to translator utils

Author: Robbepop

crates/wasmi/src/engine/translator/func/control_frame.rs

@@ -1,6 +1,6 @@
 use super::LabelRef;
 use crate::{
-    engine::{translator::Instr, BlockType, TranslationError},
+    engine::{translator::utils::Instr, BlockType, TranslationError},
     ir::{BoundedRegSpan, RegSpan},
     Engine,
     Error,

crates/wasmi/src/engine/translator/func/instr_encoder.rs

@@ -18,7 +18,13 @@ use crate::{
             ValueStack,
         },
         relink_result::RelinkResult as _,
-        utils::{BumpFuelConsumption as _, FuelInfo, IsInstructionParameter as _, WasmInteger},
+        utils::{
+            BumpFuelConsumption as _,
+            FuelInfo,
+            Instr,
+            IsInstructionParameter as _,
+            WasmInteger,
+        },
         visit_register::VisitInputRegisters as _,
     },
     ir::{
@@ -38,53 +44,6 @@ use crate::{
 use alloc::vec::{Drain, Vec};
 use core::mem;
 
-/// A reference to an instruction of the partially
-/// constructed function body of the [`InstrEncoder`].
-#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub struct Instr(u32);
-
-impl Instr {
-    /// Creates an [`Instr`] from the given `usize` value.
-    ///
-    /// # Note
-    ///
-    /// This intentionally is an API intended for test purposes only.
-    ///
-    /// # Panics
-    ///
-    /// If the `value` exceeds limitations for [`Instr`].
-    pub fn from_usize(value: usize) -> Self {
-        let value = value.try_into().unwrap_or_else(|error| {
-            panic!("invalid index {value} for instruction reference: {error}")
-        });
-        Self(value)
-    }
-
-    /// Returns an `usize` representation of the instruction index.
-    pub fn into_usize(self) -> usize {
-        self.0 as usize
-    }
-
-    /// Creates an [`Instr`] form the given `u32` value.
-    pub fn from_u32(value: u32) -> Self {
-        Self(value)
-    }
-
-    /// Returns an `u32` representation of the instruction index.
-    pub fn into_u32(self) -> u32 {
-        self.0
-    }
-
-    /// Returns the absolute distance between `self` and `other`.
-    ///
-    /// - Returns `0` if `self == other`.
-    /// - Returns `1` if `self` is adjacent to `other` in the sequence of instructions.
-    /// - etc..
-    pub fn distance(self, other: Self) -> u32 {
-        self.0.abs_diff(other.0)
-    }
-}
-
 /// Encodes Wasmi bytecode instructions to an [`Instruction`] stream.
 #[derive(Debug, Default)]
 pub struct InstrEncoder {
@@ -150,10 +109,9 @@ impl InstrSequence {
     /// If there are too many instructions in the instruction sequence.
     fn push_before(&mut self, instr: Instr, instruction: Instruction) -> Result<Instr, Error> {
         self.instrs.insert(instr.into_usize(), instruction);
-        let shifted_instr = instr
-            .into_u32()
+        let shifted_instr = u32::from(instr)
             .checked_add(1)
-            .map(Instr::from_u32)
+            .map(Instr::from)
             .unwrap_or_else(|| panic!("pushed to many instructions to a single function"));
         Ok(shifted_instr)
     }

crates/wasmi/src/engine/translator/func/mod.rs

@@ -15,7 +15,7 @@ mod simd;
 pub use self::{
     control_frame::ControlFrame,
     control_stack::ControlStack,
-    instr_encoder::{Instr, InstrEncoder},
+    instr_encoder::InstrEncoder,
     stack::TypedProvider,
 };
 use self::{
@@ -38,7 +38,7 @@ use crate::{
         code_map::CompiledFuncEntity,
         translator::{
             labels::{LabelRef, LabelRegistry},
-            utils::{FuelInfo, WasmFloat, WasmInteger, Wrap},
+            utils::{FuelInfo, Instr, WasmFloat, WasmInteger, Wrap},
             WasmTranslator,
         },
         BlockType,
@@ -224,7 +224,7 @@ impl WasmTranslator<'_> for FuncTranslator {
             //       the compiled function.
             // Note: The function enclosing block fuel instruction is always
             //       the instruction at the 0th index if fuel metering is enabled.
-            let fuel_instr = Instr::from_u32(0);
+            let fuel_instr = Instr::from(0_u32);
             let fuel_info = FuelInfo::some(fuel_costs.clone(), fuel_instr);
             self.instr_encoder
                 .bump_fuel_consumption(&fuel_info, |costs| {

crates/wasmi/src/engine/translator/labels.rs

@@ -1,4 +1,4 @@
-use crate::{engine::translator::Instr, ir::BranchOffset, Error};
+use crate::{engine::translator::utils::Instr, ir::BranchOffset, Error};
 use alloc::vec::Vec;
 use core::{
     fmt::{self, Display},
@@ -147,7 +147,7 @@ impl LabelRegistry {
     ) -> Result<BranchOffset, Error> {
         let offset = match *self.get_label(label) {
             Label::Pinned(target) => {
-                BranchOffset::from_src_to_dst(user.into_u32(), target.into_u32())?
+                BranchOffset::from_src_to_dst(u32::from(user), u32::from(target))?
             }
             Label::Unpinned => {
                 self.users.push(LabelUser::new(label, user));
@@ -206,7 +206,7 @@ impl Iterator for ResolvedUserIter<'_> {
             .resolve_label(next.label)
             .unwrap_or_else(|err| panic!("failed to resolve user: {err}"));
         let offset =
-            BranchOffset::from_src_to_dst(src.into_u32(), dst.into_u32()).map_err(Into::into);
+            BranchOffset::from_src_to_dst(u32::from(src), u32::from(dst)).map_err(Into::into);
         Some((src, offset))
     }
 }

crates/wasmi/src/engine/translator/mod.rs

@@ -18,7 +18,7 @@ use crate::Engine;
 pub use self::{
     driver::FuncTranslationDriver,
     error::TranslationError,
-    func::{FuncTranslator, FuncTranslatorAllocations, Instr},
+    func::{FuncTranslator, FuncTranslatorAllocations},
 };
 use super::code_map::CompiledFuncEntity;
 use crate::{

crates/wasmi/src/engine/translator/utils.rs

@@ -1,4 +1,3 @@
-use super::Instr;
 use crate::{
     core::{FuelCostsProvider, Typed, TypedVal, ValType},
     ir::{Const16, Instruction, Sign},
@@ -215,3 +214,56 @@ impl IsInstructionParameter for Instruction {
         )
     }
 }
+
+/// A reference to an encoded [`Instruction`].
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Instr(u32);
+
+impl From<u32> for Instr {
+    fn from(index: u32) -> Self {
+        Self(index)
+    }
+}
+
+impl From<Instr> for u32 {
+    fn from(instr: Instr) -> Self {
+        instr.0
+    }
+}
+
+impl Instr {
+    /// Creates an [`Instr`] from the given `usize` value.
+    ///
+    /// # Note
+    ///
+    /// This intentionally is an API intended for test purposes only.
+    ///
+    /// # Panics
+    ///
+    /// If the `value` exceeds limitations for [`Instr`].
+    pub fn from_usize(value: usize) -> Self {
+        let Ok(index) = u32::try_from(value) else {
+            panic!("out of bounds index {value} for `Instr`")
+        };
+        Self(index)
+    }
+
+    /// Returns an `usize` representation of the instruction index.
+    pub fn into_usize(self) -> usize {
+        match usize::try_from(self.0) {
+            Ok(index) => index,
+            Err(error) => {
+                panic!("out of bound index {} for `Instr`: {error}", self.0)
+            }
+        }
+    }
+
+    /// Returns the absolute distance between `self` and `other`.
+    ///
+    /// - Returns `0` if `self == other`.
+    /// - Returns `1` if `self` is adjacent to `other` in the sequence of instructions.
+    /// - etc..
+    pub fn distance(self, other: Self) -> u32 {
+        self.0.abs_diff(other.0)
+    }
+}