From dbf3288add6bde0d04fd16aabe4958d97d72a71d Mon Sep 17 00:00:00 2001
From: Marius Pirvu <mpirvu@ca.ibm.com>
Date: Wed, 18 Dec 2024 08:14:02 -0800
Subject: [PATCH] Remember whether dltOptLevel= is specified in a subset

The command line option -Xjit:dltOptLevel=... existed,
but it was inspected in the OpenJ9 downstream project
only when the `TR_DebugDLT` env var was set. The reason
is that we have to account for the possibility of specifying
the option in a subset and retrieving options from
subsets is relatively expensive and not something that we
may want to do too often.
This commit remembers whether `dltOptLevel=` is specified
in any subset by setting a flag in the JIT command line options.
Then, in OpenJ9 we can first check if this flag is set and
only then proceed to find the correct subset for the method
in question. This should eliminate the overhead when
-Xjit:dltOptLevel= is not specified in a subset, which is
the common case.

Signed-off-by: Marius Pirvu <mpirvu@ca.ibm.com>
---
 compiler/control/OMROptions.cpp | 14 +++++++++++++-
 compiler/control/OMROptions.hpp | 11 ++++++++---
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/compiler/control/OMROptions.cpp b/compiler/control/OMROptions.cpp
index b1e99731814..1ab22341773 100644
--- a/compiler/control/OMROptions.cpp
+++ b/compiler/control/OMROptions.cpp
@@ -3723,11 +3723,23 @@ OMR::Options::processOption(
          }
       }
    else
+      {
       processingMethod = opt->fcn;
+      }
 
    // Process this entry
    //
-   return processingMethod(option + opt->length, base, opt);
+   const char *retVal = processingMethod(option + opt->length, base, opt);
+
+   // Check to see whether the dltOptLevel option is specified in a subset
+   // and remember that information in the global JIT cmdLineOptions
+   if (optionSet)
+      {
+      if (optionSet->getOptions()->getDLTOptLevel() != -1)
+         _jitCmdLineOptions->setAnOptionSetContainsADltOptLevel(true);
+      }
+
+   return retVal;
    }
 
 
diff --git a/compiler/control/OMROptions.hpp b/compiler/control/OMROptions.hpp
index 42af02eabec..fe6a228d7de 100644
--- a/compiler/control/OMROptions.hpp
+++ b/compiler/control/OMROptions.hpp
@@ -1421,6 +1421,7 @@ class OMR_EXTENSIBLE Options
       _osVersionString = NULL;
       _allowRecompilation = false;
       _anOptionSetContainsACountValue = false;
+      _anOptionSetContainsADltOptLevel = false;
       _numInterfaceCallCacheSlots = 0;
       _numInterfaceCallStaticSlots = 0;
       _storeSinkingLastOpt = 0;
@@ -1434,9 +1435,9 @@ class OMR_EXTENSIBLE Options
       _maxStaticPICSlots = 0;
       _hotMaxStaticPICSlots = 0;
       _newAotrtDebugLevel = 0;
-      _disableDLTBytecodeIndex = 0;
-      _enableDLTBytecodeIndex = 0;
-      _dltOptLevel = 0;
+      _disableDLTBytecodeIndex = -1;
+      _enableDLTBytecodeIndex = -1;
+      _dltOptLevel = -1;
       _profilingCount = 0;
       _profilingFrequency = 0;
       _counterBucketGranularity = 0;
@@ -1665,6 +1666,9 @@ class OMR_EXTENSIBLE Options
 
    bool      anOptionSetContainsACountValue()          {return _anOptionSetContainsACountValue; }
    void      setAnOptionSetContainsACountValue(bool b) { _anOptionSetContainsACountValue = b; }
+
+   bool      anOptionSetContainsADltOptLevel()          {return _anOptionSetContainsADltOptLevel; }
+   void      setAnOptionSetContainsADltOptLevel(bool b) { _anOptionSetContainsADltOptLevel = b; }
    int32_t   getEnableDLTBytecodeIndex()       {return _enableDLTBytecodeIndex;}
    int32_t   getDisableDLTBytecodeIndex()      {return _disableDLTBytecodeIndex;}
    int32_t   getDLTOptLevel()                  {return _dltOptLevel;}
@@ -2440,6 +2444,7 @@ class OMR_EXTENSIBLE Options
    char *                      _osVersionString;
    bool                        _allowRecompilation;
    bool                        _anOptionSetContainsACountValue;
+   bool                        _anOptionSetContainsADltOptLevel;
    int32_t                     _numInterfaceCallCacheSlots;
    int32_t                     _numInterfaceCallStaticSlots;
    int32_t                     _storeSinkingLastOpt;