From 4e2bf823d13edfcd3e76e2b4754f83021adb13ce Mon Sep 17 00:00:00 2001
From: simonm <unknown>
Date: Thu, 4 Dec 1997 14:57:39 +0000
Subject: [PATCH] [project @ 1997-12-04 14:57:34 by simonm] Pull runST and
unsafeInterleaveST into UnsafeST to avoid recursive dependencies. Grrrrr.
---
ghc/lib/ghc/ArrBase.lhs | 2 +-
ghc/lib/ghc/PackBase.lhs | 1 +
ghc/lib/ghc/Unsafe.lhs | 52 ------------------------------
ghc/lib/ghc/UnsafeST.lhs | 68 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 70 insertions(+), 53 deletions(-)
create mode 100644 ghc/lib/ghc/UnsafeST.lhs
diff --git a/ghc/lib/ghc/ArrBase.lhs b/ghc/lib/ghc/ArrBase.lhs
index 558d54c5ec91..4686421b8af6 100644
--- a/ghc/lib/ghc/ArrBase.lhs
+++ b/ghc/lib/ghc/ArrBase.lhs
@@ -18,7 +18,7 @@ import STBase
import PrelBase
import CCall
import Addr
-import Unsafe ( runST )
+import UnsafeST ( runST )
import GHC
infixl 9 !, //
diff --git a/ghc/lib/ghc/PackBase.lhs b/ghc/lib/ghc/PackBase.lhs
index eaf4d6dbd051..dc0a835b62f2 100644
--- a/ghc/lib/ghc/PackBase.lhs
+++ b/ghc/lib/ghc/PackBase.lhs
@@ -46,6 +46,7 @@ import PrelList ( length )
import STBase
import ArrBase
import Addr
+import UnsafeST ( runST )
\end{code}
diff --git a/ghc/lib/ghc/Unsafe.lhs b/ghc/lib/ghc/Unsafe.lhs
index 1da8e25c4ea0..1a145af090d0 100644
--- a/ghc/lib/ghc/Unsafe.lhs
+++ b/ghc/lib/ghc/Unsafe.lhs
@@ -13,16 +13,13 @@ them to be inlined.
module Unsafe
( unsafePerformIO,
unsafeInterleaveIO,
- unsafeInterleaveST,
trace,
- runST
) where
\end{code}
\begin{code}
import PrelBase
import IOBase
-import STBase
import Addr
import {-# SOURCE #-} Error ( error )
\end{code}
@@ -59,52 +56,3 @@ trace string expr
sTDERR = (``stderr'' :: Addr)
\end{code}
-\begin{code}
-unsafeInterleaveST :: ST s a -> ST s a
-unsafeInterleaveST (ST m) = ST ( \ s ->
- let
- STret _ r = m s
- in
- STret s r)
-
-\end{code}
-
-Definition of runST
-~~~~~~~~~~~~~~~~~~~
-
-SLPJ 95/04: Why @runST@ must not have an unfolding; consider:
-\begin{verbatim}
-f x =
- runST ( \ s -> let
- (a, s') = newArray# 100 [] s
- (_, s'') = fill_in_array_or_something a x s'
- in
- freezeArray# a s'' )
-\end{verbatim}
-If we inline @runST@, we'll get:
-\begin{verbatim}
-f x = let
- (a, s') = newArray# 100 [] realWorld#{-NB-}
- (_, s'') = fill_in_array_or_something a x s'
- in
- freezeArray# a s''
-\end{verbatim}
-And now the @newArray#@ binding can be floated to become a CAF, which
-is totally and utterly wrong:
-\begin{verbatim}
-f = let
- (a, s') = newArray# 100 [] realWorld#{-NB-} -- YIKES!!!
- in
- \ x ->
- let (_, s'') = fill_in_array_or_something a x s' in
- freezeArray# a s''
-\end{verbatim}
-All calls to @f@ will share a {\em single} array! End SLPJ 95/04.
-
-\begin{code}
-runST :: (All s => ST s a) -> a
-runST st =
- case st of
- ST m -> case m realWorld# of
- STret _ r -> r
-\end{code}
diff --git a/ghc/lib/ghc/UnsafeST.lhs b/ghc/lib/ghc/UnsafeST.lhs
new file mode 100644
index 000000000000..5565178033a6
--- /dev/null
+++ b/ghc/lib/ghc/UnsafeST.lhs
@@ -0,0 +1,68 @@
+%
+% (c) The AQUA Project, Glasgow University, 1994-1996
+%
+
+\section[UnsafeST]{Module @UnsafeST@}
+
+These functions have their own module because we definitely don't want
+them to be inlined.
+
+\begin{code}
+{-# OPTIONS -fno-implicit-prelude #-}
+
+module UnsafeST (unsafeInterleaveST, runST) where
+
+import STBase
+import PrelBase
+\end{code}
+
+\begin{code}
+unsafeInterleaveST :: ST s a -> ST s a
+unsafeInterleaveST (ST m) = ST ( \ s ->
+ let
+ STret _ r = m s
+ in
+ STret s r)
+
+\end{code}
+
+Definition of runST
+~~~~~~~~~~~~~~~~~~~
+
+SLPJ 95/04: Why @runST@ must not have an unfolding; consider:
+\begin{verbatim}
+f x =
+ runST ( \ s -> let
+ (a, s') = newArray# 100 [] s
+ (_, s'') = fill_in_array_or_something a x s'
+ in
+ freezeArray# a s'' )
+\end{verbatim}
+If we inline @runST@, we'll get:
+\begin{verbatim}
+f x = let
+ (a, s') = newArray# 100 [] realWorld#{-NB-}
+ (_, s'') = fill_in_array_or_something a x s'
+ in
+ freezeArray# a s''
+\end{verbatim}
+And now the @newArray#@ binding can be floated to become a CAF, which
+is totally and utterly wrong:
+\begin{verbatim}
+f = let
+ (a, s') = newArray# 100 [] realWorld#{-NB-} -- YIKES!!!
+ in
+ \ x ->
+ let (_, s'') = fill_in_array_or_something a x s' in
+ freezeArray# a s''
+\end{verbatim}
+All calls to @f@ will share a {\em single} array! End SLPJ 95/04.
+
+\begin{code}
+runST :: (All s => ST s a) -> a
+runST st =
+ case st of
+ ST m -> case m realWorld# of
+ STret _ r -> r
+\end{code}
+
--
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