FIX #1466 (partly), which was causing concprog001(ghci) to fail

[ghc-hetmet.git] / compiler / ghci / ByteCodeGen.lhs

diff --git a/compiler/ghci/ByteCodeGen.lhs b/compiler/ghci/ByteCodeGen.lhs
index 3138e8e..846737e 100644 (file)
--- a/compiler/ghci/ByteCodeGen.lhs
+++ b/compiler/ghci/ByteCodeGen.lhs
@@ -9,7 +9,7 @@ ByteCodeGen: Generate bytecode from Core
 -- The above warning supression flag is a temporary kludge.
 -- While working on this module you are encouraged to remove it and fix
 -- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/CodingStyle#Warnings
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
 -- for details
 
 module ByteCodeGen ( UnlinkedBCO, byteCodeGen, coreExprToBCOs ) where
@@ -178,17 +178,19 @@ mkProtoBCO nm instrs_ordlist origin arity bitmap_size bitmap is_ret mallocd_bloc
         -- (hopefully rare) cases when the (overestimated) stack use
         -- exceeds iNTERP_STACK_CHECK_THRESH.
         maybe_with_stack_check
-          | is_ret = peep_d
-               -- don't do stack checks at return points;
+          | is_ret && stack_usage < aP_STACK_SPLIM = peep_d
+               -- don't do stack checks at return points,
                -- everything is aggregated up to the top BCO
-               -- (which must be a function)
-           | stack_overest >= iNTERP_STACK_CHECK_THRESH
-           = STKCHECK stack_overest : peep_d
+               -- (which must be a function).
+                -- That is, unless the stack usage is >= AP_STACK_SPLIM,
+                -- see bug #1466.
+           | stack_usage >= iNTERP_STACK_CHECK_THRESH
+           = STKCHECK stack_usage : peep_d
            | otherwise
            = peep_d    -- the supposedly common case
              
         -- We assume that this sum doesn't wrap
-        stack_overest = sum (map bciStackUse peep_d)
+        stack_usage = sum (map bciStackUse peep_d)
 
         -- Merge local pushes
         peep_d = peep (fromOL instrs_ordlist)