dcompute: Prepare pointer ABI rewrite for Vulkan support

Author: gnavdev28

gen/dcompute/abi-rewrites.h

@@ -15,6 +15,10 @@
 
 #include "gen/abi/generic.h"
 
+#include "ir/irfuncty.h"
+
+#include "llvm/IR/IntrinsicsSPIRV.h"
+
 struct DComputePointerRewrite : ABIRewrite {
   LLValue *put(DValue *v, bool isLValueExp, bool) override {
     LLValue *address = DtoLVal(v);
@@ -23,12 +27,47 @@ struct DComputePointerRewrite : ABIRewrite {
 
   LLValue *getLVal(Type *dty, LLValue *v) override {
     LLValue *mem = DtoAlloca(dty, ".DComputePointerRewrite_param_storage");
-    DtoStore(v, mem);
+    LLType *realStructTy = DtoMemType(dty);
+    LLValue *field = DtoGEP(realStructTy, mem, 0u, 0u);
+    
+    if (gIR && gIR->dcomputetarget &&
+        gIR->dcomputetarget->target == DComputeTarget::ID::Vulkan) {
+      auto ptrOpt = toDcomputePointer(static_cast<TypeStruct *>(dty)->sym);
+      assert(ptrOpt && "DComputePointerRewrite expects ldc.dcompute.Pointer");
+      const auto &ptr = *ptrOpt;
+      llvm::Type *elemTy = DtoType(ptr.type);
+      int realAS = gIR->dcomputetarget->mapping[ptr.addrspace];
+      
+      llvm::Value *ofType = llvm::PoisonValue::get(elemTy);
+      llvm::Metadata *md = llvm::ValueAsMetadata::get(ofType);
+      llvm::Value *mdVal = llvm::MetadataAsValue::get(gIR->context(), md);
+      
+#if LLVM_VERSION_MAJOR >= 20
+      llvm::Function *assignFn = llvm::Intrinsic::getOrInsertDeclaration(
+          &gIR->module, llvm::Intrinsic::spv_assign_ptr_type, {v->getType()});
+#else
+      llvm::Function *assignFn = llvm::Intrinsic::getDeclaration(
+          &gIR->module, llvm::Intrinsic::spv_assign_ptr_type, {v->getType()});
+#endif
+      gIR->ir->CreateCall(assignFn->getFunctionType(), assignFn,
+                          {v, mdVal, llvm::ConstantInt::get(llvm::Type::getInt32Ty(gIR->context()), realAS)});
+    }
+    
+    DtoStore(v, field);
     return mem;
   }
 
   LLType *type(Type *t) override {
-    auto ptr = toDcomputePointer(static_cast<TypeStruct *>(t)->sym);
-    return ptr->toLLVMType(true);
+    auto ptrOpt = toDcomputePointer(static_cast<TypeStruct *>(t)->sym);
+    assert(ptrOpt && "DComputePointerRewrite expects ldc.dcompute.Pointer");
+    return ptrOpt->toLLVMType(true);
+  }
+
+  void applyTo(IrFuncTyArg &arg, LLType *finalLType = nullptr) override {
+    arg.rewrite = this;
+    arg.ltype = finalLType ? finalLType : this->type(arg.type);
+    arg.byref = false;
+    arg.attrs.removeAttribute(llvm::Attribute::Dereferenceable);
+    arg.attrs.removeAttribute(llvm::Attribute::NonNull);
   }
 };

gen/dcompute/target.h

@@ -28,7 +28,7 @@ class DComputeTarget {
 public:
   llvm::LLVMContext &ctx;
   int tversion; // OpenCL or CUDA CC version:major*100 + minor*10
-  enum class ID { Host = 0, OpenCL = 1, CUDA = 2 };
+  enum class ID { Host = 0, OpenCL = 1, CUDA = 2, Vulkan = 3 };
   ID target;    // ID for codegen time conditional compilation.
   const char *short_name;
   const char *binSuffix;

runtime/druntime/src/ldc/dcompute.d

@@ -14,6 +14,7 @@ enum ReflectTarget : uint
     Host = 0,
     OpenCL = 1,
     CUDA = 2,
+    Vulkan = 3,
 }
 /**
  * The pseudo conditional compilation function.