36 lines
958 B
Rust
36 lines
958 B
Rust
//! A basic `Variable` implementation.
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//!
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//! Frontends can use any indexing scheme they see fit and
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//! generate the appropriate `Variable` instances.
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//!
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//! Note: The `Variable` is used by Cranelift to index into densely allocated
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//! arrays containing information about your mutable variables
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//! Thus, make sure that Variable's indexes are allocated contiguously and
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//! starting at `0`.
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use core::u32;
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use cranelift_codegen::entity::EntityRef;
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///! An opaque reference to a variable.
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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pub struct Variable(u32);
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impl Variable {
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/// Create a new Variable with the given index.
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pub fn with_u32(index: u32) -> Self {
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debug_assert!(index < u32::MAX);
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Self(index)
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}
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}
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impl EntityRef for Variable {
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fn new(index: usize) -> Self {
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debug_assert!(index < (u32::MAX as usize));
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Self(index as u32)
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}
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fn index(self) -> usize {
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self.0 as usize
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}
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}
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