Fix for gtpin when stackcall is enabled. rera pass is off, free GRFs are

not computed.

Change-Id: I210e3de74838b90bdedbfa96612a9639755ae62e

Author: pratikashar

visa/FlowGraph.cpp

@@ -6900,19 +6900,24 @@ void* gtPinData::getGTPinInfoBuffer(unsigned int &bufferSize)
     gtpin::igc::igc_init_t t;
     std::vector<unsigned char> buffer;
     unsigned int numTokens = 0;
+    auto stackABI = kernel.fg.getIsStackCallFunc() || kernel.fg.getHasStackCalls();
     bufferSize = 0;
 
     memset(&t, 0, sizeof(t));
 
     t.version = gtpin::igc::GTPIN_IGC_INTERFACE_VERSION;
     if (gtpin_init->grf_info)
     {
-        t.grf_info = 1;
+        if (!stackABI)
+            t.grf_info = 1;
         numTokens++;
     }
 
     if (gtpin_init->re_ra)
-        t.re_ra = 1;
+    {
+        if(!stackABI)
+            t.re_ra = 1;
+    }
 
     if (gtpin_init->srcline_mapping && kernel.getOptions()->getOption(vISA_GenerateDebugInfo))
         t.srcline_mapping = 1;

visa/GraphColor.cpp

@@ -9540,14 +9540,17 @@ int GlobalRA::coloringRegAlloc()
             jitInfo->spillMemUsed =
                 (builder.kernel.fg.paramOverflowAreaOffset +
                     builder.kernel.fg.paramOverflowAreaSize) * 16 - globalScratchOffset;
+
+            // reserve spillMemUsed #bytes before 8kb boundary
+            kernel.getGTPinData()->setScratchNextFree(8*1024 - (kernel.getGTPinData()->getGTPinInit() ?
+                kernel.getGTPinData()->getGTPinInit()->scratch_area_size : 0));
         } else {
             jitInfo->spillMemUsed = spillMemUsed;
+            kernel.getGTPinData()->setScratchNextFree(spillMemUsed);
         }
         jitInfo->numGRFSpillFill = GRFSpillFillCount;
     }
 
-    kernel.getGTPinData()->setScratchNextFree(spillMemUsed);
-
     if (builder.getOption(vISA_LocalDeclareSplitInGlobalRA))
     {
         removeSplitDecl();

visa/Optimizer.cpp

@@ -858,6 +858,10 @@ bool Optimizer::isCopyPropProfitable(G4_INST* movInst) const
 
 void Optimizer::reRAPostSchedule()
 {
+    // No rera for stackcall functions
+    if (kernel.fg.getHasStackCalls() || kernel.fg.getIsStackCallFunc())
+        return;
+
     std::vector<Assignment> assignments;
     auto finalizerInfo = *builder.getJitInfo();
     auto oldRAType = kernel.getRAType();