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Addressed more review comments.

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This commit is contained in:
Chris Fallin
2021-08-30 17:51:55 -07:00
parent 6d313f2b56
commit 3a18564e98
6 changed files with 150 additions and 30 deletions
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15
src/checker.rs
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@@ -17,6 +17,16 @@
//! conceptually generates a symbolic value "Vn" when storing to (or
//! modifying) a virtual register.
//!
//! These symbolic values are precise but partial: in other words, if
//! a physical register is described as containing a virtual register
//! at a program point, it must actually contain the value of this
//! register (modulo any analysis bugs); but it may resolve to
//! `Conflicts` even in cases where one *could* statically prove that
//! it contains a certain register, because the analysis is not
//! perfectly path-sensitive or value-sensitive. However, all
//! assignments *produced by our register allocator* should be
//! analyzed fully precisely.
//!
//! Operand constraints (fixed register, register, any) are also checked
//! at each operand.
//!
@@ -24,7 +34,8 @@
//!
//! - map of: Allocation -> lattice value (top > Vn symbols (unordered) > bottom)
//!
//! And the transfer functions for instructions are:
//! And the transfer functions for instructions are (where `A` is the
//! above map from allocated physical registers to symbolic values):
//!
//! - `Edit::Move` inserted by RA: [ alloc_d := alloc_s ]
//!
@@ -36,7 +47,7 @@
//! machine code, but we include their allocations so that this
//! checker can work)
//!
//! A[A_i] := meet(A_j, A_k, ...)
//! A[A_i] := meet(A[A_j], A[A_k], ...)
//!
//! - statement in pre-regalloc function [ V_i := op V_j, V_k, ... ]
//! with allocated form [ A_i := op A_j, A_k, ... ]