Refactor type checks when popping refs#1730
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fitzgen merged 1 commit intobytecodealliance:mainfrom Aug 21, 2024
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This commit refactors users of `pop_ref` during validation to be able to pass in an expected type. This removes the need for a few manual `is_subtype` checks and helps centralize type-checking in one location.
alexcrichton
commented
Aug 20, 2024
Comment on lines
1133
to
1135
| /// instructions. Returns the given `heap_type` as a `ValType`. | ||
| fn check_downcast( | ||
| &mut self, | ||
| nullable: bool, | ||
| mut heap_type: HeapType, | ||
| inst_name: &str, | ||
| ) -> Result<ValType> { | ||
| fn check_downcast(&mut self, nullable: bool, mut heap_type: HeapType) -> Result<RefType> { | ||
| self.resources | ||
| .check_heap_type(&mut heap_type, self.offset)?; | ||
|
|
||
| let sub_ty = RefType::new(nullable, heap_type) | ||
| .map(ValType::from) | ||
| .ok_or_else(|| { | ||
| BinaryReaderError::new("implementation limit: type index too large", self.offset) | ||
| })?; | ||
|
|
||
| let sup_ty = self.pop_ref()?.unwrap_or_else(|| { | ||
| sub_ty | ||
| .as_reference_type() | ||
| .expect("we created this as a reference just above") | ||
| }); | ||
| let sup_ty = RefType::new(true, self.resources.top_type(&sup_ty.heap_type())) | ||
| let sub_ty = RefType::new(nullable, heap_type).ok_or_else(|| { | ||
| BinaryReaderError::new("implementation limit: type index too large", self.offset) | ||
| })?; | ||
| let sup_ty = RefType::new(true, self.resources.top_type(&heap_type)) | ||
| .expect("can't panic with non-concrete heap types"); | ||
|
|
||
| if !self.resources.is_subtype(sub_ty, sup_ty.into()) { | ||
| bail!( | ||
| self.offset, | ||
| "{inst_name}'s heap type must be a sub type of the type on the stack: \ | ||
| {sub_ty} is not a sub type of {sup_ty}" | ||
| ); | ||
| } | ||
|
|
||
| self.pop_ref(Some(sup_ty))?; | ||
| Ok(sub_ty) | ||
| } |
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@fitzgen asking for your review on this PR, and in particular for the changes in this function. I don't believe I'm preserving the precise shape of what was here previously but I think I'm maintaining the spec still, but wanted to confirm.
fitzgen
approved these changes
Aug 21, 2024
Comment on lines
1133
to
1135
| /// instructions. Returns the given `heap_type` as a `ValType`. | ||
| fn check_downcast( | ||
| &mut self, | ||
| nullable: bool, | ||
| mut heap_type: HeapType, | ||
| inst_name: &str, | ||
| ) -> Result<ValType> { | ||
| fn check_downcast(&mut self, nullable: bool, mut heap_type: HeapType) -> Result<RefType> { | ||
| self.resources | ||
| .check_heap_type(&mut heap_type, self.offset)?; | ||
|
|
||
| let sub_ty = RefType::new(nullable, heap_type) | ||
| .map(ValType::from) | ||
| .ok_or_else(|| { | ||
| BinaryReaderError::new("implementation limit: type index too large", self.offset) | ||
| })?; | ||
|
|
||
| let sup_ty = self.pop_ref()?.unwrap_or_else(|| { | ||
| sub_ty | ||
| .as_reference_type() | ||
| .expect("we created this as a reference just above") | ||
| }); | ||
| let sup_ty = RefType::new(true, self.resources.top_type(&sup_ty.heap_type())) | ||
| let sub_ty = RefType::new(nullable, heap_type).ok_or_else(|| { | ||
| BinaryReaderError::new("implementation limit: type index too large", self.offset) | ||
| })?; | ||
| let sup_ty = RefType::new(true, self.resources.top_type(&heap_type)) | ||
| .expect("can't panic with non-concrete heap types"); | ||
|
|
||
| if !self.resources.is_subtype(sub_ty, sup_ty.into()) { | ||
| bail!( | ||
| self.offset, | ||
| "{inst_name}'s heap type must be a sub type of the type on the stack: \ | ||
| {sub_ty} is not a sub type of {sup_ty}" | ||
| ); | ||
| } | ||
|
|
||
| self.pop_ref(Some(sup_ty))?; | ||
| Ok(sub_ty) | ||
| } |
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This commit refactors users of
pop_refduring validation to be able to pass in an expected type. This removes the need for a few manualis_subtypechecks and helps centralize type-checking in one location.