Some code cleanup & fixed problem of used bdefore definitions

[fw/sdcc] / src / SDCClrange.c

diff --git a/src/SDCClrange.c b/src/SDCClrange.c
index eea9a0751f7958277bc042ed43411a5be17ccc35..7c71b130b3c4396277055e44c45302df25effd82 100644 (file)
--- a/src/SDCClrange.c
+++ b/src/SDCClrange.c
@@ -24,6 +24,7 @@
 -------------------------------------------------------------------------*/
 
 #include "common.h"
+#include "limits.h"
 
 int iCodeSeq = 0 ;
 hTab *liveRanges = NULL;
@@ -185,6 +186,85 @@ void setToRange (operand *op,int to, bool check)
        OP_LIVETO(op) = to;
 }
 
+/*-----------------------------------------------------------------*/
+/* firstDeOf - finds the first definition in seq for op            */
+/*-----------------------------------------------------------------*/
+static iCode *firstDefOf (operand *op)
+{
+    int i;
+    iCode *ric=NULL,*lic=NULL;
+    int fSeq = INT_MAX;
+
+    if (!OP_DEFS(op))
+       return NULL;
+
+    for (i=0; i < OP_DEFS(op)->size ;i++) {
+       if (bitVectBitValue(OP_DEFS(op),i) &&
+           (lic = hTabItemWithKey(iCodehTab,i)) &&
+           lic->seq < fSeq) {
+
+           fSeq = lic->seq ;
+           ric = lic;
+       }
+    }
+    return ric;
+}
+/*-----------------------------------------------------------------*/
+/* useDefLoopCheck - check for uses before init inside loops       */
+/*-----------------------------------------------------------------*/
+static void useDefLoopCheck(operand *op,iCode *ic)
+{
+    /* this is for situations like the following
+       int a,b;
+
+       while (...) {
+            a = ... ;
+            ...
+            _some_usage_of_b_;
+           ...
+           b = ... ;
+           } 
+       in this case the definition of 'b' will flow to the usages
+       but register allocator cannot handle these situations.so
+       will mark as spilt */
+
+    int i =0, fdSeq ;
+    int er=0;
+    iCode *tic ;
+    
+    /* get the first definition */
+    if (!(tic = firstDefOf(op)))
+       return ;
+    
+    fdSeq = tic->seq;
+    /* now go thru the usages & make sure they follow
+       the first definition */
+    for (i=0; i <= OP_USES(op)->size;i++ ) {
+       if (bitVectBitValue(OP_USES(op),i) &&
+           (tic = hTabItemWithKey(iCodehTab,i)) &&
+           tic->seq < fdSeq){
+           er = 1;
+           break;
+       }
+    }
+
+    /* found a usage without definition */
+    if (er) {
+       if (OP_SYMBOL(op)->isreqv && SPIL_LOC(op) ) {
+           
+           werror(W_LOCAL_NOINIT,                          
+                  SPIL_LOC(op)->name,                     
+                  ic->filename,ic->lineno);
+       } else {
+           
+           werror(W_LOCAL_NOINIT,                         
+                  OP_SYMBOL(op)->name,                   
+                  ic->filename,ic->lineno); 
+       }
+       OP_SYMBOL(op)->isspilt = 1;
+    }
+}
+
 
 /*-----------------------------------------------------------------*/
 /* operandLUse - check and set the last use for a given operand    */
@@ -213,10 +293,12 @@ operand *operandLUse (operand *op, eBBlock **ebbs,
     }  
     ic->uses = bitVectSetBit(ic->uses,op->key);
     
+    if (!OP_SYMBOL(op)->udChked)
     {
        link *type = operandType(op);
        link *etype = getSpec(type);
-
+       
+       OP_SYMBOL(op)->udChked = 1;
        /* good place to check if unintialised */
        if ((IS_TRUE_SYMOP(op)  || OP_SYMBOL(op)->isreqv) &&
            OP_SYMBOL(op)->islocal    &&
@@ -240,56 +322,18 @@ operand *operandLUse (operand *op, eBBlock **ebbs,
                           OP_SYMBOL(op)->name,                   
                           ic->filename,ic->lineno); 
                }
-           } 
-       }
+           } else {
+               if (ebp->depth && op->usesDefs && 
+                   !OP_SYMBOL(op)->_isparm) {
+                   /* check non-inits inside loops */
+                   useDefLoopCheck(op,ic);
+               }
+           }
+       }       
     }
     return op;
 }
 
-/*-----------------------------------------------------------------*/
-/* compLastUse - computes the last usage with certainty            */
-/*-----------------------------------------------------------------*/
-void compLastUse ()
-{
-    symbol *sym;
-    int key;
-    /* the strategy here is to look for live ranges that are not
-       induction variables, and find out the usage icode with the
-       highest sequence number then set the to range to that icode
-       sequence */
-    /* once fully tested we can use only this routine to mark the
-       to range that will reduce a lot of computations in the 
-       markLiveRanges routine */
-    for (sym = hTabFirstItem(liveRanges,&key) ; sym;
-        sym = hTabNextItem(liveRanges,&key)) {
-
-       int i ;
-       int maxKey = 0 ;
-
-       if (sym->isind)
-           continue ;
-
-       if (!sym->uses)
-           continue ;
-
-       /* go thru all the usages of this live range and find out
-          the maximum sequence number of the icode that used it */
-       for (i = 0 ; i < sym->uses->size ; i++ ) {
-           iCode *uic ;
-
-           if (!bitVectBitValue(sym->uses,i))
-               continue ;
-           
-           if ((uic = hTabItemWithKey(iCodehTab,i)))
-               maxKey = ( uic->seq > maxKey ? uic->seq : maxKey );         
-       }
-
-       /* got it */
-       if (maxKey)
-           sym->liveTo = maxKey;
-    }
-}
-
 /*-----------------------------------------------------------------*/
 /* killAllAlive - mark all the definitions living with this seq    */
 /*-----------------------------------------------------------------*/
@@ -499,7 +543,6 @@ void computeLiveRanges (eBBlock **ebbs, int count )
     for ( i = 0 ; i < count; i++ ) 
        markLiveRanges (ebbs[i],ebbs,count);
     
-/*     compLastUse(); */
     /* mark the ranges live for each point */
     rlivePoint (ebbs,count);
 }