SPARC NCG: HpLim is now always stored on the stack, not in a register

   This fixes the out of memory errors we were getting on sparc
   after the following patch:

     Fri Mar 13 03:45:16 PDT 2009  Simon Marlow <marlowsd@gmail.com>
     * Instead of a separate context-switch flag, set HpLim to zero
     Ignore-this: 6c5bbe1ce2c5ef551efe98f288483b0
     This reduces the latency between a context-switch being triggered and
     the thread returning to the scheduler, which in turn should reduce the
     cost of the GC barrier when there are many cores.

diff --git a/compiler/nativeGen/SPARC/Regs.hs b/compiler/nativeGen/SPARC/Regs.hs
index 7911958..b129d44 100644 (file)
--- a/compiler/nativeGen/SPARC/Regs.hs
+++ b/compiler/nativeGen/SPARC/Regs.hs
@@ -188,12 +188,14 @@ freeReg regno
        -- %l6(r22) - %l7(r23) are allocable --------------
        
        -- %i0(r24) - %i5(r29)
-       --      are STG regs Sp, Base, SpLim, Hp, HpLim, R6
+       --      are STG regs Sp, Base, SpLim, Hp, R6
        24      -> fastBool False
        25      -> fastBool False
        26      -> fastBool False
        27      -> fastBool False
-       28      -> fastBool False
+
+       -- %i5(r28) is allocable --------------------------
+
        29      -> fastBool False
        
        -- %i6(r30) 
@@ -263,7 +265,6 @@ globalRegMaybe gg
        Sp              -> Just (RealReg 24)    -- %i0
        SpLim           -> Just (RealReg 26)    -- %i2
        Hp              -> Just (RealReg 27)    -- %i3
-       HpLim           -> Just (RealReg 28)    -- %i4
 
        BaseReg         -> Just (RealReg 25)    -- %i1
                

diff --git a/includes/MachRegs.h b/includes/MachRegs.h
index f51f782..593989d 100644 (file)
--- a/includes/MachRegs.h
+++ b/includes/MachRegs.h
@@ -543,6 +543,10 @@
 /* -----------------------------------------------------------------------------
    The Sun SPARC register mapping
 
+   !! IMPORTANT: if you change this register mapping you must also update
+                 compiler/nativeGen/SPARC/Regs.hs. That file handles the
+                 mapping for the NCG. This one only affects via-c code.
+
    The SPARC register (window) story: Remember, within the Haskell
    Threaded World, we essentially ``shut down'' the register-window
    mechanism---the window doesn't move at all while in this World.  It
@@ -590,11 +594,11 @@
      %i1        Base
      %i2        SpLim
      %i3        Hp
+     %i4        alloc
      %i5        R6
      %i6                    C frame ptr
      %i7                    C ret addr
      
-
    The paired nature of the floating point registers causes complications for
    the native code generator.  For convenience, we pretend that the first 22
    fp regs %f0 .. %f21 are actually 11 double regs, and the remaining 10 are