From 7758625d3fea67e55e98e7e4103d56c9918365be Mon Sep 17 00:00:00 2001
From: ArielG-NV <159081215+ArielG-NV@users.noreply.github.com>
Date: Fri, 29 Aug 2025 15:52:34 -0700
Subject: [CBP] Pointer frontend changes + groupshared pointer support (#7848)

Resolves #7628
Resolves: #8197

Primary Goals:
1. Add `Access` to pointer
2. AddressSpace::GroupShared support for pointers (SPIR-V)
3. Add `__getAddress()` to replace `&`
* `&` is not updated to `require(cpu)` since slangpy uses `&`. This
means we must: (1) merge PR; (2) replace `&` with `__getAddress()`; (3)
add `require(cpu)` to `&`

Changes:
* Added to `Ptr` the `Access` generic argument & logic (for
`Access::Read`).
* Moved the generic argument `AddressSpace` from `Ptr` to the end of the
type.
* Added pointer casting support between any `Ptr` as long as the
`AddressSpace` is the same
* Disallow globallycoherent T* and coherent T*
* Disallow const T*, T const*, and const T*
* Fixed .natvis display of `ConstantValue` `ValOperandNode`
* Support generic resolution of type-casted integers
* Added `VariablePointer` emitting for spirv + other minor logic needed
for groupshared pointers

Breaking Changes:
* Anyone using the `AddressSpace` of `Ptr` will now have to account for
the `Access` argument
* we disallow various syntax paired with `Ptr` and `T*`

---------

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>
---
 source/slang/slang-emit-spirv.cpp | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

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

diff --git a/source/slang/slang-emit-spirv.cpp b/source/slang/slang-emit-spirv.cpp
index 2127141bd..5036333c1 100644
--- a/source/slang/slang-emit-spirv.cpp
+++ b/source/slang/slang-emit-spirv.cpp
@@ -1844,7 +1844,8 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
                             (IRPtrTypeBase*)inst))
                         emitOpTypeForwardPointer(resultSpvType, storageClass);
                 }
-                if (storageClass == SpvStorageClassPhysicalStorageBuffer)
+                if (storageClass == SpvStorageClassPhysicalStorageBuffer ||
+                    storageClass == SpvStorageClassStorageBuffer)
                 {
                     if (m_decoratedSpvInsts.add(getID(resultSpvType)))
                     {
@@ -3271,6 +3272,7 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
             builder.getPtrType(
                 kIROp_PtrType,
                 spvAsmBuiltinVar->getDataType(),
+                AccessQualifier::ReadWrite,
                 AddressSpace::BuiltinInput),
             kind,
             spvAsmBuiltinVar);
@@ -3868,20 +3870,24 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
         return spvDebugLocalVar;
     }
 
-    bool isLegalType(IRInst* type)
+    // Returns true if the given type is allowed to emit for a `DebugVar`.
+    // Other types may not be illegal, but Slang currently does not support
+    // emitting these other DebugVar types.
+    bool isAllowedDebugVarType(IRInst* type)
     {
         switch (type->getOp())
         {
         case kIROp_UnsizedArrayType:
             return false;
         case kIROp_ArrayType:
-            return isLegalType(as<IRArrayType>(type)->getElementType());
+            return isAllowedDebugVarType(as<IRArrayType>(type)->getElementType());
         case kIROp_VectorType:
         case kIROp_StructType:
         case kIROp_MatrixType:
             return true;
         case kIROp_PtrType:
-            return as<IRPtrTypeBase>(type)->getAddressSpace() == AddressSpace::UserPointer;
+            return as<IRPtrTypeBase>(type)->getAddressSpace() == AddressSpace::UserPointer ||
+                   as<IRPtrTypeBase>(type)->getAddressSpace() == AddressSpace::GroupShared;
         default:
             if (as<IRBasicType>(type))
                 return true;
@@ -3899,7 +3905,7 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
         builder.setInsertBefore(debugVar);
         auto varType = tryGetPointedToType(&builder, debugVar->getDataType());
 
-        if (!isLegalType(varType))
+        if (!isAllowedDebugVarType(varType))
             return nullptr;
 
         IRSizeAndAlignment sizeAlignment;
@@ -9473,10 +9479,16 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex
     {
         if (auto ptrType = as<IRPtrTypeBase>(type))
         {
-            if (ptrType->getAddressSpace() == AddressSpace::StorageBuffer)
+            switch (ptrType->getAddressSpace())
             {
+            case AddressSpace::StorageBuffer:
+                ensureExtensionDeclaration(UnownedStringSlice("SPV_KHR_variable_pointers"));
+                requireSPIRVCapability(SpvCapabilityVariablePointersStorageBuffer);
+                break;
+            case AddressSpace::GroupShared:
                 ensureExtensionDeclaration(UnownedStringSlice("SPV_KHR_variable_pointers"));
                 requireSPIRVCapability(SpvCapabilityVariablePointers);
+                break;
             }
         }
     }
-- 
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