From e5a75563a1ba2e378353af8b937b8b7bb0fe2c2b Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Tue, 21 Jun 2022 14:55:59 -0700
Subject: Lower throwing COM interface method. (#2282)

* Lower throwing COM interface method.

* Fix.

* Fix warnings.

Co-authored-by: Yong He <yhe@nvidia.com>
---
 source/slang/slang-ir-lower-com-methods.cpp | 138 ++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 source/slang/slang-ir-lower-com-methods.cpp

(limited to 'source/slang/slang-ir-lower-com-methods.cpp')

diff --git a/source/slang/slang-ir-lower-com-methods.cpp b/source/slang/slang-ir-lower-com-methods.cpp
new file mode 100644
index 000000000..6c3a3f289
--- /dev/null
+++ b/source/slang/slang-ir-lower-com-methods.cpp
@@ -0,0 +1,138 @@
+// slang-ir-lower-com-methods.cpp
+
+#include "slang-ir-lower-com-methods.h"
+
+#include "slang-ir.h"
+#include "slang-ir-insts.h"
+#include "slang-ir-marshal-native-call.h"
+#include "slang-ir-inst-pass-base.h"
+
+namespace Slang
+{
+
+struct ComMethodLoweringContext : public InstPassBase
+{
+    DiagnosticSink* diagnosticSink = nullptr;
+
+    NativeCallMarshallingContext marshal;
+
+    OrderedHashSet<IRLookupWitnessMethod*> comCallees;
+
+    ComMethodLoweringContext(IRModule* inModule)
+        : InstPassBase(inModule)
+    {}
+
+    void processComCall(IRCall* comCall)
+    {
+        IRBuilder builder(&sharedBuilderStorage);
+        builder.setInsertBefore(comCall);
+        auto callee = as<IRLookupWitnessMethod>(comCall->getCallee());
+        SLANG_ASSERT(callee);
+
+        comCallees.Add(callee);
+        
+        auto calleeType = as<IRFuncType>(comCall->getCallee()->getDataType());
+        SLANG_ASSERT(calleeType);
+
+        auto nativeFuncType = marshal.getNativeFuncType(builder, calleeType);
+        ShortList<IRInst*> args;
+        for (UInt i = 0; i < comCall->getArgCount(); i++)
+            args.add(comCall->getArg(i));
+        auto currentBlock = builder.getBlock();
+        auto nextInst = comCall->getNextInst();
+        auto newResult = marshal.marshalNativeCall(
+            builder,
+            calleeType,
+            nativeFuncType,
+            comCall->getCallee(),
+            args.getCount(),
+            args.getArrayView().getBuffer());
+
+        comCall->replaceUsesWith(newResult);
+        if (builder.getBlock() != currentBlock)
+        {
+            // `marshalNativeCall` may have replaced the original call with branch insts.
+            // If this is the case, we need to move all insts after the original call in the original
+            // basic block to the new basic block.
+            while (nextInst)
+            {
+                auto next = nextInst->getNextInst();
+                nextInst->removeFromParent();
+                nextInst->insertAtEnd(builder.getBlock());
+                nextInst = next;
+            }
+        }
+        comCall->removeAndDeallocate();
+    }
+
+    void processCall(IRCall* inst)
+    {
+        auto funcValue = inst->getOperand(0);
+
+        // Detect if this is a call into a COM interface method.
+        if (funcValue->getOp() == kIROp_lookup_interface_method)
+        {
+            const auto operand0TypeOp = funcValue->getOperand(0)->getDataType();
+            if (auto tableType = as<IRWitnessTableTypeBase>(operand0TypeOp))
+            {
+                if (tableType->getConformanceType()->findDecoration<IRComInterfaceDecoration>())
+                {
+                    processComCall(inst);
+                    return;
+                }
+            }
+        }
+    }
+
+    void processInterfaceType(IRInterfaceType* interfaceType)
+    {
+        if (!interfaceType->findDecoration<IRComInterfaceDecoration>())
+            return;
+        IRBuilder builder(&sharedBuilderStorage);
+        for (UInt i = 0; i < interfaceType->getOperandCount(); i++)
+        {
+            auto entry = as<IRInterfaceRequirementEntry>(interfaceType->getOperand(i));
+            if (!entry)
+                continue;
+            if (auto funcType = as<IRFuncType>(entry->getRequirementVal()))
+            {
+                builder.setInsertBefore(funcType);
+                entry->setRequirementVal(marshal.getNativeFuncType(builder, funcType));
+            }
+        }
+    }
+
+    void processModule()
+    {
+        sharedBuilderStorage.init(module);
+
+        // Deduplicate equivalent types.
+        sharedBuilderStorage.deduplicateAndRebuildGlobalNumberingMap();   
+
+        // Translate all Calls to interface methods.
+        processInstsOfType<IRCall>(kIROp_Call, [this](IRCall* inst) { processCall(inst); });
+
+        // Update functypes of com callees.
+        for (auto callee : comCallees)
+        {
+            IRBuilder builder(&sharedBuilderStorage);
+            builder.setInsertBefore(callee);
+            auto nativeType = marshal.getNativeFuncType(builder, as<IRFuncType>(callee->getDataType()));
+            callee->setFullType(nativeType);
+        }
+
+        // Update func types of COM interfaces.
+        processInstsOfType<IRInterfaceType>(kIROp_InterfaceType, [this](IRInterfaceType* inst) { processInterfaceType(inst); });
+
+    }
+};
+
+void lowerComMethods(IRModule* module, DiagnosticSink* sink)
+{
+    ComMethodLoweringContext context(module);
+    context.diagnosticSink = sink;
+    context.marshal.diagnosticSink = sink;
+
+    return context.processModule();
+}
+}
-- 
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