X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fiface%2FMkIface.lhs;h=f972a91f3d8c6182acf2a15e68767842598f8159;hb=2509cf09915f514d8a77f21c0564137af618af76;hp=c0b9717c64d98afa0ff8dadcc168e45307d3b2d3;hpb=23e4e1039c16bb30fec04b5006bfc0f4989239d9;p=ghc-hetmet.git

diff --git a/compiler/iface/MkIface.lhs b/compiler/iface/MkIface.lhs
index c0b9717..f972a91 100644
--- a/compiler/iface/MkIface.lhs
+++ b/compiler/iface/MkIface.lhs
@@ -131,7 +131,7 @@ We produce a line for every module B below the module, A, currently being
 compiled:
 	import B <n> ;
 to record the fact that A does import B indirectly.  This is used to decide
-to look to look for B.hi rather than B.hi-boot when compiling a module that
+to look for B.hi rather than B.hi-boot when compiling a module that
 imports A.  This line says that A imports B, but uses nothing in it.
 So we'll get an early bale-out when compiling A if B's version changes.
 
@@ -181,6 +181,10 @@ code of A, and thereby haul in all the stuff reachable from it.
 haul in all the unfoldings for B, in case the module that imports A *is*
 compiled with -O.  I think this is the case.]
 
+SimonM [30/11/2007]: I believe the above is all out of date; the
+current implementation doesn't do it this way.  Instead, when any of
+the dependencies of a declaration changes, the version of the
+declaration itself changes.
 
 \begin{code}
 #include "HsVersions.h"
@@ -704,17 +708,23 @@ computeChangedOccs ver_fn this_module old_usages eq_info
     -- return True if an external name has changed
     name_changed :: Name -> Bool
     name_changed nm
-        | Just ents <- lookupUFM usg_modmap (moduleName mod) 
-        = case lookupUFM ents parent_occ of
-                Nothing -> pprPanic "computeChangedOccs" (ppr nm)
-                Just v  -> v < new_version
+        | Just ents <- lookupUFM usg_modmap (moduleName mod),
+          Just v    <- lookupUFM ents parent_occ
+        = v < new_version
+        | modulePackageId mod == this_pkg
+        = WARN(True, ptext SLIT("computeChangedOccs") <+> ppr nm) True
+        -- should really be a panic, see #1959.  The problem is that the usages doesn't
+        -- contain all the names that might be referred to by unfoldings.  So as a
+        -- conservative workaround we just assume these names have changed.
         | otherwise = False -- must be in another package
       where
          mod = nameModule nm
          (parent_occ, new_version) = ver_fn nm
 
+    this_pkg = modulePackageId this_module
+
     -- Turn the usages from the old ModIface into a mapping
-    usg_modmap = listToUFM [ (usg_mod usg, listToUFM (usg_entities usg))
+    usg_modmap = listToUFM [ (usg_name usg, listToUFM (usg_entities usg))
                            | usg <- old_usages ]
 
     get_local_eq_info :: GenIfaceEq NameSet -> GenIfaceEq OccSet
@@ -749,6 +759,11 @@ computeChangedOccs ver_fn this_module old_usages eq_info
 
 type OccIfaceEq = GenIfaceEq OccSet
 
+instance Outputable OccIfaceEq where
+  ppr Equal          = ptext SLIT("Equal")
+  ppr NotEqual       = ptext SLIT("NotEqual")
+  ppr (EqBut occset) = ptext SLIT("EqBut") <+> ppr (occSetElts occset)
+
 changedWrt :: OccSet -> OccIfaceEq -> Bool
 changedWrt so_far Equal        = False
 changedWrt so_far NotEqual     = True