57 lines
1.6 KiB
Lean4
57 lines
1.6 KiB
Lean4
import Spa.Language.Base
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import Spa.Language.Semantics
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import Spa.Language.Graphs
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import Mathlib.Data.Finset.Sort
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import Mathlib.Data.String.Basic
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namespace Spa
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structure Program where
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rootStmt : Stmt
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/-- A memoized copy of the control-flow graph. This field is an
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implementation detail to avoid re-computing `Graph.wrap` and `Stmt.cfg`
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every time the program's control flow graph is needed -/
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cfgCache : Thunk Graph := Thunk.mk fun _ => Graph.wrap rootStmt.cfg
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namespace Program
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variable (p : Program)
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-- Runtime implementation of `cfg`: read the memoized graph.
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private def cfgImpl : Graph := p.cfgCache.get
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@[implemented_by cfgImpl]
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def cfg : Graph := Graph.wrap p.rootStmt.cfg
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abbrev State : Type := p.cfg.Index
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def vars : List String := p.rootStmt.vars.sort (· ≤ ·)
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lemma vars_nodup : p.vars.Nodup := Finset.sort_nodup _ _
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def states : List p.State := p.cfg.indices
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lemma states_complete (s : p.State) : s ∈ p.states := p.cfg.mem_indices s
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lemma states_nodup : p.states.Nodup := p.cfg.nodup_indices
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def code (st : p.State) : Option BasicStmt := p.cfg.nodes st
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def incoming (s : p.State) : List p.State := p.cfg.predecessors s
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def initialState : p.State := Graph.wrapInput p.rootStmt.cfg
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def finalState : p.State := Graph.wrapOutput p.rootStmt.cfg
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lemma mem_incoming_of_edge {s₁ s₂ : p.State}
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(h : (s₁, s₂) ∈ p.cfg.edges) : s₁ ∈ p.incoming s₂ :=
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p.cfg.mem_predecessors_of_edge h
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lemma incoming_initialState_eq_nil : p.incoming p.initialState = [] :=
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GGraph.wrap_predecessors_eq_nil p.rootStmt.cfg p.initialState
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(by rw [Graph.wrap_inputs]; exact List.mem_singleton_self _)
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end Program
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end Spa
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