Split warm and cold blocks

- identify last warm instruction during instruction selection - the code is only enabled if -Xjit:splitWarmAndColdBlocks option is on
eclipse-openj9 · May 21, 2024 · 17bed20 · 17bed20
1 parent e2fa955
commit 17bed20
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Showing 2 changed files with 34 additions and 3 deletions.
diff --git a/runtime/compiler/codegen/J9CodeGenerator.cpp b/runtime/compiler/codegen/J9CodeGenerator.cpp
@@ -1707,6 +1707,12 @@ J9::CodeGenerator::doInstructionSelection()
 
    bool fixedUpBlock = false;
 
+   if (self()->comp()->getOption(TR_SplitWarmAndColdBlocks) &&
+       !self()->comp()->compileRelocatableCode())
+      {
+      setInstructionSelectionInWarmCodeCache();
+      }
+
    for (TR::TreeTop *tt = self()->comp()->getStartTree(); tt; tt = self()->getCurrentEvaluationTreeTop()->getNextTreeTop())
       {
       if(traceLiveMon)
@@ -2166,6 +2172,26 @@ J9::CodeGenerator::doInstructionSelection()
       if (doEvaluation)
          self()->evaluate(node);
 
+      if (self()->comp()->getOption(TR_SplitWarmAndColdBlocks) &&
+          opCode == TR::BBEnd)
+         {
+         TR::Block *b = self()->getCurrentEvaluationBlock();
+
+         if (b->isLastWarmBlock())
+            {
+            resetInstructionSelectionInWarmCodeCache();
+            // Mark the split point between warm and cold instructions, so they
+            // can be allocated in different code sections.
+            //
+            TR::Instruction *lastInstr = b->getLastInstruction();
+
+            if (self()->comp()->getOption(TR_TraceCG))
+               traceMsg(self()->comp(), "%s Last warm instruction is %p\n", SPLIT_WARM_COLD_STRING, lastInstr);
+
+            lastInstr->setLastWarmInstruction(true);
+            self()->setLastWarmInstruction(lastInstr);
+            }
+         }
 
       if (self()->comp()->getOption(TR_TraceCG) || debug("traceGRA"))
          {
@@ -5008,7 +5034,7 @@ void
 J9::CodeGenerator::trimCodeMemoryToActualSize()
    {
    uint8_t *bufferStart = self()->getBinaryBufferStart();
-   size_t actualCodeLengthInBytes = self()->getCodeEnd() - bufferStart;
+   size_t actualCodeLengthInBytes = self()->getWarmCodeEnd() - bufferStart;
 
    TR::VMAccessCriticalSection trimCodeMemoryAllocation(self()->comp());
    self()->getCodeCache()->trimCodeMemoryAllocation(bufferStart, actualCodeLengthInBytes);

diff --git a/runtime/compiler/runtime/MetaData.cpp b/runtime/compiler/runtime/MetaData.cpp
@@ -1494,8 +1494,13 @@ createMethodMetaData(
 
    data->startPC = (UDATA)comp->cg()->getCodeStart();
    data->endPC = (UDATA)comp->cg()->getCodeEnd();
-   data->startColdPC = (UDATA)0;
-   data->endWarmPC = data->endPC;
+   data->startColdPC = (UDATA)comp->cg()->getColdCodeStart();
+
+   if (data->startColdPC)
+      data->endWarmPC = (UDATA)comp->cg()->getWarmCodeEnd();
+   else
+      data->endWarmPC = data->endPC;
+
    data->codeCacheAlloc = (UDATA)comp->cg()->getBinaryBufferStart();
 
    if (fourByteOffsets)