PIX: Educate type system about samplers and resources, base classes (#4937)

These fixes were the result of a single shader from a well-known game engine, all of which resulted in mismatched offsets between PIX's offsets-into-fake-allocas and the offsets into aggregates for dbg.value statements.
-Base class sizes weren't being added to derived classes
-Samplers+Resources weren't being given any size at all
-Raygen payloads (referred to by pointer) were triggering an assert
Added a new set of tests for the type system to exercise these.

Author: jeffnn

lib/DxilDia/DxilDiaSymbolManager.cpp

@@ -607,6 +607,7 @@ class SymbolManagerInit {
     void Embed(const TypeInfo &TI);
 
     void AddBasicType(llvm::DIBasicType *BT);
+    void AppendSize(uint64_t baseSize);
 
   private:
     DWORD m_dwTypeID;
@@ -1151,6 +1152,12 @@ void dxil_dia::hlsl_symbols::SymbolManagerInit::TypeInfo::Embed(const TypeInfo &
   m_dwCurrentSizeInBytes += TI.m_dwCurrentSizeInBytes;
 }
 
+void dxil_dia::hlsl_symbols::SymbolManagerInit::TypeInfo::AppendSize(
+    uint64_t baseSize) {
+  static constexpr DWORD kNumBitsPerByte = 8;
+  m_dwCurrentSizeInBytes += baseSize / kNumBitsPerByte;
+}
+
 void dxil_dia::hlsl_symbols::SymbolManagerInit::TypeInfo::AddBasicType(llvm::DIBasicType *BT) {
   m_Layout.emplace_back(BT);
 
@@ -1439,6 +1446,33 @@ HRESULT dxil_dia::hlsl_symbols::SymbolManagerInit::CreateBasicType(DWORD dwParen
   return S_OK;
 }
 
+static uint64_t getBaseClassSize(llvm::DIType * Ty)
+{
+    uint64_t sizeInBits = Ty->getSizeInBits();
+    auto *DerivedTy = llvm::dyn_cast<llvm::DIDerivedType>(Ty);
+    if (DerivedTy != nullptr) {
+      // Working around a bug where byte size is stored instead of bit size
+      if (sizeInBits == 4 && Ty->getSizeInBits() == 32) {
+        sizeInBits = 32;
+      }
+      if (sizeInBits == 0) {
+        const llvm::DITypeIdentifierMap EmptyMap;
+        switch (DerivedTy->getTag()) {
+        case llvm::dwarf::DW_TAG_restrict_type:
+        case llvm::dwarf::DW_TAG_reference_type:
+        case llvm::dwarf::DW_TAG_const_type:
+        case llvm::dwarf::DW_TAG_typedef: {
+          llvm::DIType *baseType = DerivedTy->getBaseType().resolve(EmptyMap);
+          if (baseType != nullptr) {
+            return getBaseClassSize(baseType);
+          }
+        }
+        }
+      }
+    }
+    return sizeInBits;
+}
+
 HRESULT dxil_dia::hlsl_symbols::SymbolManagerInit::CreateCompositeType(DWORD dwParentID, llvm::DICompositeType *CT, DWORD *pNewTypeID) {
   switch (CT->getTag()) {
   case llvm::dwarf::DW_TAG_array_type: {
@@ -1529,13 +1563,27 @@ HRESULT dxil_dia::hlsl_symbols::SymbolManagerInit::CreateCompositeType(DWORD dwP
   TypeInfo *udtTI;
   IFR(GetTypeInfo(CT, &udtTI));
   auto udtScope = BeginUDTScope(udtTI);
-  for (llvm::DINode *N : CT->getElements()) {
-    if (auto *Field = llvm::dyn_cast<llvm::DIType>(N)) {
-      DWORD dwUnusedFieldID;
-      IFR(CreateType(Field, &dwUnusedFieldID));
+  if (CT->getElements().size() == 0) {
+    // "Resources" (textures, samplers, etc.) are composite types without any elements,
+    // but they do have a size.
+    udtTI->AppendSize(CT->getSizeInBits());
+  } else {
+    for (llvm::DINode *N : CT->getElements()) {
+      if (auto *Field = llvm::dyn_cast<llvm::DIType>(N)) {
+        DWORD dwUnusedFieldID;
+        IFR(CreateType(Field, &dwUnusedFieldID));
+        if (Field->getTag() == llvm::dwarf::DW_TAG_inheritance) {
+          // The base class is a type of its own, so will have contributed to
+          // its own TypeInfo. But we still need to remember the size that it
+          // contributed to this type:
+          auto *DerivedType = llvm::cast<llvm::DIDerivedType>(Field);
+          const llvm::DITypeIdentifierMap EmptyMap;
+          llvm::DIType *BaseType = DerivedType->getBaseType().resolve(EmptyMap);
+          udtTI->AppendSize(getBaseClassSize(BaseType));
+        }
+      }
     }
   }
-
   return S_OK;
 }
 

lib/DxilPIXPasses/DxilDbgValueToDbgDeclare.cpp

@@ -365,7 +365,8 @@ static OffsetInBits SplitValue(
   else
   {
     assert(VTy->isFloatTy() || VTy->isDoubleTy() || VTy->isHalfTy() ||
-           VTy->isIntegerTy(32) || VTy->isIntegerTy(64) || VTy->isIntegerTy(16));
+           VTy->isIntegerTy(32) || VTy->isIntegerTy(64) || VTy->isIntegerTy(16) ||
+           VTy->isPointerTy());
     Values->emplace_back(ValueAndOffset{V, CurrentOffset});
     CurrentOffset += VTy->getScalarSizeInBits();
   }