From ba0986ac66e3a22d211ad3707ad037fdc10910af Mon Sep 17 00:00:00 2001
From: Martin Neupauer <xmaton@messengeruser.com>
Date: Mon, 15 May 2023 16:50:05 +0000
Subject: SERVER-76896 Add direct access for two common slot accessors

---
 src/mongo/db/exec/sbe/values/slot.h     |  5 +++++
 src/mongo/db/exec/sbe/vm/vm.cpp         | 30 +++++++++++++++++++++++++++++-
 src/mongo/db/exec/sbe/vm/vm.h           |  6 ++++++
 src/mongo/db/exec/sbe/vm/vm_printer.cpp |  2 ++
 4 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/mongo/db/exec/sbe/values/slot.h b/src/mongo/db/exec/sbe/values/slot.h
index fdbf99605b7..3b07477a921 100644
--- a/src/mongo/db/exec/sbe/values/slot.h
+++ b/src/mongo/db/exec/sbe/values/slot.h
@@ -70,6 +70,11 @@ public:
      * make a deep copy. The returned value is owned by the caller.
      */
     virtual std::pair<TypeTags, Value> copyOrMoveValue() = 0;
+
+    template <typename T>
+    bool is() const {
+        return dynamic_cast<const T*>(this) != nullptr;
+    }
 };
 
 /**
diff --git a/src/mongo/db/exec/sbe/vm/vm.cpp b/src/mongo/db/exec/sbe/vm/vm.cpp
index 5bdcc7496a2..2f7c1bee391 100644
--- a/src/mongo/db/exec/sbe/vm/vm.cpp
+++ b/src/mongo/db/exec/sbe/vm/vm.cpp
@@ -33,6 +33,7 @@
 #include "mongo/platform/basic.h"
 
 #include "mongo/db/exec/sbe/expressions/expression.h"
+#include "mongo/db/exec/sbe/expressions/runtime_environment.h"
 #include "mongo/db/exec/sbe/vm/vm.h"
 #include "mongo/db/exec/sbe/vm/vm_printer.h"
 
@@ -77,6 +78,8 @@ namespace vm {
 int Instruction::stackOffset[Instruction::Tags::lastInstruction] = {
     1,   // pushConstVal
     1,   // pushAccessVal
+    1,   // pushOwnedAccessorVal
+    1,   // pushEnvAccessorVal
     1,   // pushMoveVal
     1,   // pushLocalVal
     1,   // pushMoveLocalVal
@@ -480,8 +483,15 @@ void CodeFragment::appendConstVal(value::TypeTags tag, value::Value val) {
 
 void CodeFragment::appendAccessVal(value::SlotAccessor* accessor) {
     Instruction i;
-    i.tag = Instruction::pushAccessVal;
+    i.tag = [](value::SlotAccessor* accessor) {
+        if (accessor->is<value::OwnedValueAccessor>()) {
+            return Instruction::pushOwnedAccessorVal;
+        } else if (accessor->is<RuntimeEnvironment::Accessor>()) {
+            return Instruction::pushEnvAccessorVal;
+        }
 
+        return Instruction::pushAccessVal;
+    }(accessor);
     auto offset = allocateSpace(sizeof(Instruction) + sizeof(accessor));
 
     offset += writeToMemory(offset, i);
@@ -7247,6 +7257,24 @@ void ByteCode::runInternal(const CodeFragment* code, int64_t position) {
 
                 break;
             }
+            case Instruction::pushOwnedAccessorVal: {
+                auto accessor = readFromMemory<value::OwnedValueAccessor*>(pcPointer);
+                pcPointer += sizeof(accessor);
+
+                auto [tag, val] = accessor->getViewOfValue();
+                pushStack(false, tag, val);
+
+                break;
+            }
+            case Instruction::pushEnvAccessorVal: {
+                auto accessor = readFromMemory<RuntimeEnvironment::Accessor*>(pcPointer);
+                pcPointer += sizeof(accessor);
+
+                auto [tag, val] = accessor->getViewOfValue();
+                pushStack(false, tag, val);
+
+                break;
+            }
             case Instruction::pushMoveVal: {
                 auto accessor = readFromMemory<value::SlotAccessor*>(pcPointer);
                 pcPointer += sizeof(accessor);
diff --git a/src/mongo/db/exec/sbe/vm/vm.h b/src/mongo/db/exec/sbe/vm/vm.h
index 2f43bdf5bb6..17b3eb29b7f 100644
--- a/src/mongo/db/exec/sbe/vm/vm.h
+++ b/src/mongo/db/exec/sbe/vm/vm.h
@@ -265,6 +265,8 @@ struct Instruction {
     enum Tags {
         pushConstVal,
         pushAccessVal,
+        pushOwnedAccessorVal,
+        pushEnvAccessorVal,
         pushMoveVal,
         pushLocalVal,
         pushMoveLocalVal,
@@ -433,6 +435,10 @@ struct Instruction {
                 return "pushConstVal";
             case pushAccessVal:
                 return "pushAccessVal";
+            case pushOwnedAccessorVal:
+                return "pushOwnedAccessorVal";
+            case pushEnvAccessorVal:
+                return "pushEnvAccessorVal";
             case pushMoveVal:
                 return "pushMoveVal";
             case pushLocalVal:
diff --git a/src/mongo/db/exec/sbe/vm/vm_printer.cpp b/src/mongo/db/exec/sbe/vm/vm_printer.cpp
index 921463cab28..e545136cb56 100644
--- a/src/mongo/db/exec/sbe/vm/vm_printer.cpp
+++ b/src/mongo/db/exec/sbe/vm/vm_printer.cpp
@@ -296,6 +296,8 @@ public:
                         .writeValueToStream(tag, val);
                     break;
                 }
+                case Instruction::pushOwnedAccessorVal:
+                case Instruction::pushEnvAccessorVal:
                 case Instruction::pushAccessVal:
                 case Instruction::pushMoveVal: {
                     auto accessor = readFromMemory<value::SlotAccessor*>(pcPointer);
-- 
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