62 lines
2.3 KiB
Text
62 lines
2.3 KiB
Text
/-
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Copyright (c) 2021 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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module
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prelude
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public import Init.System.IO
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public section
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namespace Lean
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private builtin_initialize importingRef : IO.Ref Bool ← IO.mkRef false
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private builtin_initialize runInitializersRef : IO.Ref Bool ← IO.mkRef false
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/--
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By default the `initialize` code is not executed when importing .olean files.
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When this flag is set to `true`, the initializers are executed.
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This method is meant to be used by the Lean frontend only.
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Remark: it is not safe to run `initialize` code when using multiple threads.
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Remark: Any loaded native Lean code must match its imported version. In particular,
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no two versions of the same module may be loaded when this flag is set.
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No native code may be loaded after its module has been imported.
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Remark: Compacted module regions must not be freed when using this flag as the
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cached initializer results may reference objects in them.
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Remark: The Lean frontend executes this method at startup time.
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-/
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@[export lean_enable_initializer_execution]
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unsafe def enableInitializersExecution : IO Unit :=
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runInitializersRef.set true
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def isInitializerExecutionEnabled : IO Bool :=
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runInitializersRef.get
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/--
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We say Lean is "initializing" when it is executing `builtin_initialize` declarations or importing modules.
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Recall that Lean executes `initialize` declarations while importing modules.
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-/
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def initializing : IO Bool :=
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IO.initializing <||> importingRef.get
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/--
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Execute `x` with "importing" flag turned on.
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When the "importing" flag is set to true, we allow user-extensions defined with
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the `initialize` command to update global references.
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IMPORTANT: There is no semaphore controlling the access to these global references.
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We assume these global references are updated by a single execution thread.
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This is true in the Lean frontend where we process the `import` commands at the beginning
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of the execution only. Users must make sure that when `importModules` is used, there is only
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one execution thread accessing the global references.
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-/
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def withImporting (x : IO α) : IO α :=
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try
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importingRef.set true
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x
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finally
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importingRef.set false
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runInitializersRef.set false
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end Lean
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