From 060071604bc715951ddf940a51ced1da48b3dd10 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Thu, 29 Oct 2020 10:21:07 -0700
Subject: Generate `switch` based dynamic dispatch logic. (#1591)

Co-authored-by: Tim Foley <tim.foley.is@gmail.com>
---
 source/slang/slang-emit-cpp.cpp | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

(limited to 'source/slang/slang-emit-cpp.cpp')

diff --git a/source/slang/slang-emit-cpp.cpp b/source/slang/slang-emit-cpp.cpp
index 6a82815a9..d1250357a 100644
--- a/source/slang/slang-emit-cpp.cpp
+++ b/source/slang/slang-emit-cpp.cpp
@@ -1651,35 +1651,27 @@ void CPPSourceEmitter::_emitWitnessTableDefinitions()
         m_writer->emit(getName(witnessTable));
         m_writer->emit(" = {\n");
         m_writer->indent();
-        bool isFirstEntry = true;
+        auto seqIdDecoration = witnessTable->findDecoration<IRSequentialIDDecoration>();
+        SLANG_ASSERT(seqIdDecoration);
+        m_writer->emit((UInt)seqIdDecoration->getSequentialID());
         for (Index i = 0; i < sortedWitnessTableEntries.getCount(); i++)
         {
             auto entry = sortedWitnessTableEntries[i];
             if (auto funcVal = as<IRFunc>(entry->satisfyingVal.get()))
             {
-                if (!isFirstEntry)
-                    m_writer->emit(",\n");
-                else
-                    isFirstEntry = false;
-
+                m_writer->emit(",\n");
                 m_writer->emit(getName(funcVal));
             }
             else if (auto witnessTableVal = as<IRWitnessTable>(entry->getSatisfyingVal()))
             {
-                if (!isFirstEntry)
-                    m_writer->emit(",\n");
-                else
-                    isFirstEntry = false;
+                m_writer->emit(",\n");
                 m_writer->emit("&");
                 m_writer->emit(getName(witnessTableVal));
             }
             else if (entry->getSatisfyingVal() &&
                      isPointerOfType(entry->getSatisfyingVal()->getDataType(), kIROp_RTTIType))
             {
-                if (!isFirstEntry)
-                    m_writer->emit(",\n");
-                else
-                    isFirstEntry = false;
+                m_writer->emit(",\n");
                 emitInstExpr(entry->getSatisfyingVal(), getInfo(EmitOp::General));
             }
             else
@@ -1704,6 +1696,7 @@ void CPPSourceEmitter::emitInterface(IRInterfaceType* interfaceType)
     emitSimpleType(interfaceType);
     m_writer->emit("\n{\n");
     m_writer->indent();
+    m_writer->emit("uint32_t sequentialID;\n");
     for (UInt i = 0; i < interfaceType->getOperandCount(); i++)
     {
         auto entry = as<IRInterfaceRequirementEntry>(interfaceType->getOperand(i));
@@ -2196,6 +2189,12 @@ bool CPPSourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inOut
             m_writer->emit(getName(inst->getOperand(1)));
             return true;
         }
+        case kIROp_GetSequentialID:
+        {
+            emitInstExpr(inst->getOperand(0), inOuterPrec);
+            m_writer->emit("->sequentialID");
+            return true;
+        }
         case kIROp_WitnessTable:
         {
             m_writer->emit("(&");
-- 
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