diff options
| -rw-r--r-- | compiler/main/StaticPtrTable.hs | 6 | ||||
| -rw-r--r-- | compiler/rename/RnExpr.hs | 6 | ||||
| -rw-r--r-- | compiler/typecheck/TcRnTypes.hs | 4 | ||||
| -rw-r--r-- | docs/users_guide/glasgow_exts.rst | 7 | ||||
| -rw-r--r-- | libraries/base/GHC/StaticPtr.hs | 5 |
5 files changed, 20 insertions, 8 deletions
diff --git a/compiler/main/StaticPtrTable.hs b/compiler/main/StaticPtrTable.hs index 23d02f81ec..47547fca5b 100644 --- a/compiler/main/StaticPtrTable.hs +++ b/compiler/main/StaticPtrTable.hs @@ -60,13 +60,13 @@ Here is a running example: in ...(static k)... * The renamer looks for out-of-scope names in the body of the static - form, as always If all names are in scope, the free variables of the + form, as always. If all names are in scope, the free variables of the body are stored in AST at the location of the static form. * The typechecker verifies that all free variables occurring in the static form are floatable to top level (see Note [Meaning of - IdBindingInfo] in TcRnTypes). In our example, 'k' is floatable, even - though it is bound in a nested let, we are fine. + IdBindingInfo] in TcRnTypes). In our example, 'k' is floatable. + Even though it is bound in a nested let, we are fine. * The desugarer replaces the static form with an application of the function 'makeStatic' (defined in module GHC.StaticPtr.Internal of diff --git a/compiler/rename/RnExpr.hs b/compiler/rename/RnExpr.hs index 8f719c4b0c..22e474b481 100644 --- a/compiler/rename/RnExpr.hs +++ b/compiler/rename/RnExpr.hs @@ -371,9 +371,9 @@ rnExpr e@(ELazyPat {}) = patSynErr e empty * * ************************************************************************ -For the static form we check that the free variables are all top-level -value bindings. This is done by checking that the name is external or -wired-in. See the Notes about the NameSorts in Name.hs. +For the static form we check that it is not used in splices. +We also collect the free variables of the term which come from +this module. See Note [Grand plan for static forms] in StaticPtrTable. -} rnExpr e@(HsStatic _ expr) = do diff --git a/compiler/typecheck/TcRnTypes.hs b/compiler/typecheck/TcRnTypes.hs index f2309c8b9e..7e347ffe2c 100644 --- a/compiler/typecheck/TcRnTypes.hs +++ b/compiler/typecheck/TcRnTypes.hs @@ -1176,8 +1176,8 @@ ClosedLet means that - For the ClosedTypeId field see Note [Bindings with closed types] For (static e) to be valid, we need for every 'x' free in 'e', -x's binding must be floatable to top level. Specifically: - * x's RhsNames must be non-empty +that x's binding is floatable to the top level. Specifically: + * x's RhsNames must be empty * x's type has no free variables See Note [Grand plan for static forms] in StaticPtrTable.hs. This test is made in TcExpr.checkClosedInStaticForm. diff --git a/docs/users_guide/glasgow_exts.rst b/docs/users_guide/glasgow_exts.rst index ab92375c52..3edb8d657f 100644 --- a/docs/users_guide/glasgow_exts.rst +++ b/docs/users_guide/glasgow_exts.rst @@ -12937,6 +12937,13 @@ While the following definitions are rejected: :: entered on the REPL may not. This is a limitation of GHCi; see :ghc-ticket:`12356` for details. +.. note:: + + The set of keys used for locating static pointers in the Static Pointer + Table is not guaranteed to remain stable for different program binaries. + Or in other words, only processes launched from the same program binary + are guaranteed to use the same set of keys. + .. _typechecking-static-pointers: Static semantics of static pointers diff --git a/libraries/base/GHC/StaticPtr.hs b/libraries/base/GHC/StaticPtr.hs index 65ec483577..92829acb73 100644 --- a/libraries/base/GHC/StaticPtr.hs +++ b/libraries/base/GHC/StaticPtr.hs @@ -28,6 +28,11 @@ -- table is known as the Static Pointer Table. The reference can then be -- dereferenced to obtain the value. -- +-- The various communicating processes need to aggree on the keys used to refer +-- to the values in the Static Pointer Table, or lookups will fail. Only +-- processes launched from the same program binary are guaranteed to use the +-- same set of keys. +-- ----------------------------------------------------------------------------- module GHC.StaticPtr |