lean4-htt/src/Lean/Compiler/InlineAttrs.lean

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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
-/
prelude
import Lean.Attributes
namespace Lean.Compiler
inductive InlineAttributeKind where
| inline | noinline | macroInline | inlineIfReduce | alwaysInline
deriving Inhabited, BEq, Hashable
/--
This is an approximate test for testing whether `declName` can be annotated with the `[macro_inline]` attribute or not.
-/
private def isValidMacroInline (declName : Name) : CoreM Bool := do
let .defnInfo info ← getConstInfo declName
| return false
unless info.all.length = 1 do
-- We do not allow `[macro_inline]` attributes at mutual recursive definitions
return false
let env ← getEnv
let isRec (declName' : Name) : Bool :=
isBRecOnRecursor env declName' ||
declName' == ``WellFounded.fix ||
declName' == declName ++ `_unary -- Auxiliary declaration created by `WF` module
if Option.isSome <| info.value.find? fun e => e.isConst && isRec e.constName! then
-- It contains a `brecOn` or `WellFounded.fix` application. So, it should be recursvie
return false
return true
/--
Changes the inlining behavior. This attribute comes in several variants:
- `@[inline]`: marks the definition to be inlined when it is appropriate.
- `@[inline_if_reduce]`: marks the definition to be inlined if an application of it after inlining
and applying reduction isn't a `match` expression. This attribute can be used for inlining
structurally recursive functions.
- `@[noinline]`: marks the definition to never be inlined.
- `@[always_inline]`: marks the definition to always be inlined.
- `@[macro_inline]`: marks the definition to always be inlined at the beginning of compilation.
This makes it possible to define functions that evaluate some of their parameters lazily.
Example:
```
@[macro_inline]
def test (x y : Nat) : Nat :=
if x = 42 then x else y
#eval test 42 (2^1000000000000) -- doesn't compute 2^1000000000000
```
Only non-recursive functions may be marked `@[macro_inline]`.
-/
@[builtin_doc]
builtin_initialize inlineAttrs : EnumAttributes InlineAttributeKind ←
registerEnumAttributes
[(`inline, "mark definition to be inlined", .inline),
(`inline_if_reduce, "mark definition to be inlined when resultant term after reduction is not a `cases_on` application", .inlineIfReduce),
(`noinline, "mark definition to never be inlined", .noinline),
(`macro_inline, "mark definition to always be inlined before ANF conversion", .macroInline),
(`always_inline, "mark definition to be always inlined", .alwaysInline)]
fun declName kind => do
ofExcept <| checkIsDefinition (← getEnv) declName
if kind matches .macroInline then
unless (← isValidMacroInline declName) do
throwError "invalid use of `[macro_inline]` attribute at `{declName}`, it is not supported in this kind of declaration, declaration must be a non-recursive definition"
def setInlineAttribute (env : Environment) (declName : Name) (kind : InlineAttributeKind) : Except String Environment :=
inlineAttrs.setValue env declName kind
def getInlineAttribute? (env : Environment) (declName : Name) : Option InlineAttributeKind :=
inlineAttrs.getValue env declName
private def hasInlineAttrCore (env : Environment) (kind : InlineAttributeKind) (declName : Name) : Bool :=
match inlineAttrs.getValue env declName with
| some k => kind == k
| _ => false
abbrev hasInlineAttribute (env : Environment) (declName : Name) : Bool :=
hasInlineAttrCore env .inline declName
def hasInlineIfReduceAttribute (env : Environment) (declName : Name) : Bool :=
hasInlineAttrCore env .inlineIfReduce declName
def hasNoInlineAttribute (env : Environment) (declName : Name) : Bool :=
hasInlineAttrCore env .noinline declName
def hasMacroInlineAttribute (env : Environment) (declName : Name) : Bool :=
hasInlineAttrCore env .macroInline declName
abbrev hasAlwaysInlineAttribute (env : Environment) (declName : Name) : Bool :=
hasInlineAttrCore env .alwaysInline declName
end Lean.Compiler