[HLSL] Global resource arrays element access (#152454)

Adds support for accessing individual resources from fixed-size global resource arrays.

Design proposal:
https://github.com/llvm/wg-hlsl/blob/main/proposals/0028-resource-arrays.md

Enables indexing into globally scoped, fixed-size resource arrays to retrieve individual resources. The initialization logic is primarily handled during codegen. When a global resource array is indexed, the
codegen translates the `ArraySubscriptExpr` AST node into a constructor call for the corresponding resource record type and binding.

To support this behavior, Sema needs to ensure that:
- The constructor for the specific resource type is instantiated.
- An implicit binding attribute is added to resource arrays that lack explicit bindings (#152452).

Closes #145424

1 files changed, 9 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 4146876..677d8bc 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -5796,11 +5796,16 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
       (D->getType()->isCUDADeviceBuiltinSurfaceType() ||
        D->getType()->isCUDADeviceBuiltinTextureType());
   if (getLangOpts().CUDA &&
-      (IsCUDASharedVar || IsCUDAShadowVar || IsCUDADeviceShadowVar))
+      (IsCUDASharedVar || IsCUDAShadowVar || IsCUDADeviceShadowVar)) {
     Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
-  else if (D->hasAttr<LoaderUninitializedAttr>())
+  } else if (getLangOpts().HLSL &&
+             (D->getType()->isHLSLResourceRecord() ||
+              D->getType()->isHLSLResourceRecordArray())) {
+    Init = llvm::PoisonValue::get(getTypes().ConvertType(ASTTy));
+    NeedsGlobalCtor = D->getType()->isHLSLResourceRecord();
+  } else if (D->hasAttr<LoaderUninitializedAttr>()) {
     Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
-  else if (!InitExpr) {
+  } else if (!InitExpr) {
     // This is a tentative definition; tentative definitions are
     // implicitly initialized with { 0 }.
     //
@@ -5821,11 +5826,7 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
       if (D->getType()->isReferenceType())
         T = D->getType();
 
-      if (getLangOpts().HLSL &&
-          D->getType().getTypePtr()->isHLSLResourceRecord()) {
-        Init = llvm::PoisonValue::get(getTypes().ConvertType(ASTTy));
-        NeedsGlobalCtor = true;
-      } else if (getLangOpts().CPlusPlus) {
+      if (getLangOpts().CPlusPlus) {
         Init = EmitNullConstant(T);
         if (!IsDefinitionAvailableExternally)
           NeedsGlobalCtor = true;