lean4-htt/src/Lean/Compiler/Util.lean
2020-10-27 18:29:19 -07:00

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/-
Copyright (c) 2019 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
import Lean.Environment
namespace Lean.Compiler
def neutralExpr : Expr := mkConst `_neutral
def unreachableExpr : Expr := mkConst `_unreachable
def objectType : Expr := mkConst `_obj
def voidType : Expr := mkConst `_void
def mkLcProof (pred : Expr) := mkApp (mkConst `lcProof []) pred
namespace atMostOnce
structure AtMostOnceData :=
(found result : Bool)
def Visitor := AtMostOnceData → AtMostOnceData
@[inline] def seq (f g : Visitor) : Visitor := fun d =>
match f d with
| ⟨found, false⟩ => ⟨found, false⟩
| other => g other
instance : AndThen Visitor := ⟨seq⟩
@[inline] def skip : Visitor := id
@[inline] def visitFVar (x y : Name) : Visitor
| d@{result := false, ..} => d
| {found := false, result := true} => {found := x == y, result := true}
| {found := true, result := true} => {found := true, result := x != y}
def visit (x : Name) : Expr → Visitor
| Expr.fvar y _ => visitFVar y x
| Expr.app f a _ => visit x a >> visit x f
| Expr.lam _ d b _ => visit x d >> visit x b
| Expr.forallE _ d b _ => visit x d >> visit x b
| Expr.letE _ t v b _ => visit x t >> visit x v >> visit x b
| Expr.mdata _ e _ => visit x e
| Expr.proj _ _ e _ => visit x e
| _ => skip
end atMostOnce
open atMostOnce (visit) in
/-- Return true iff the free variable with id `x` occurs at most once in `e` -/
@[export lean_at_most_once]
def atMostOnce (e : Expr) (x : Name) : Bool :=
let {result := result, ..} := visit x e {found := false, result := true}
result
/- Helper functions for creating auxiliary names used in compiler passes. -/
@[export lean_mk_eager_lambda_lifting_name]
def mkEagerLambdaLiftingName (n : Name) (idx : Nat) : Name :=
mkNameStr n ("_elambda_" ++ toString idx)
@[export lean_is_eager_lambda_lifting_name]
def isEagerLambdaLiftingName : Name → Bool
| Name.str p s _ => "_elambda".isPrefixOf s || isEagerLambdaLiftingName p
| Name.num p _ _ => isEagerLambdaLiftingName p
| _ => false
/-- Return the name of new definitions in the a given declaration.
Here we consider only declarations we generate code for.
We use this definition to implement `add_and_compile`. -/
@[export lean_get_decl_names_for_code_gen]
private def getDeclNamesForCodeGen : Declaration → List Name
| Declaration.defnDecl { name := n, .. } => [n]
| Declaration.mutualDefnDecl defs => defs.map fun d => d.name
| Declaration.opaqueDecl { name := n, .. } => [n]
| _ => []
def checkIsDefinition (env : Environment) (n : Name) : Except String Unit :=
match env.find? n with
| (some (ConstantInfo.defnInfo _)) => Except.ok ()
| (some (ConstantInfo.opaqueInfo _)) => Except.ok ()
| none => Except.error s!"unknow declaration '{n}'"
| _ => Except.error s!"declaration is not a definition '{n}'"
/--
We generate auxiliary unsafe definitions for regular recursive definitions.
The auxiliary unsafe definition has a clear runtime cost execution model.
This function returns the auxiliary unsafe definition name for the given name. -/
@[export lean_mk_unsafe_rec_name]
def mkUnsafeRecName (declName : Name) : Name :=
mkNameStr declName "_unsafe_rec"
/-- Return `some _` if the given name was created using `mkUnsafeRecName` -/
@[export lean_is_unsafe_rec_name]
def isUnsafeRecName? : Name → Option Name
| Name.str n "_unsafe_rec" _ => some n
| _ => none
end Lean.Compiler