[HLSL] Add Buffer def to frontend (#141086)

Fixes #138902

Defines the `Buffer<>` type in the clang frontend. Lowering from
IR->Target Machine is already handled by other code

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/lib/Sema/HLSLExternalSemaSource.cpp b/clang/lib/Sema/HLSLExternalSemaSource.cpp
index 38bde7c..726581d 100644
--- a/clang/lib/Sema/HLSLExternalSemaSource.cpp
+++ b/clang/lib/Sema/HLSLExternalSemaSource.cpp
@@ -266,6 +266,19 @@ void HLSLExternalSemaSource::defineHLSLTypesWithForwardDeclarations() {
       *SemaPtr, HLSLNamespace, /*isTypedBuffer*/ true);
   ConceptDecl *StructuredBufferConcept = constructBufferConceptDecl(
       *SemaPtr, HLSLNamespace, /*isTypedBuffer*/ false);
+
+  Decl = BuiltinTypeDeclBuilder(*SemaPtr, HLSLNamespace, "Buffer")
+             .addSimpleTemplateParams({"element_type"}, TypedBufferConcept)
+             .finalizeForwardDeclaration();
+
+  onCompletion(Decl, [this](CXXRecordDecl *Decl) {
+    setupBufferType(Decl, *SemaPtr, ResourceClass::SRV, /*IsROV=*/false,
+                    /*RawBuffer=*/false)
+        .addArraySubscriptOperators()
+        .addLoadMethods()
+        .completeDefinition();
+  });
+
   Decl = BuiltinTypeDeclBuilder(*SemaPtr, HLSLNamespace, "RWBuffer")
              .addSimpleTemplateParams({"element_type"}, TypedBufferConcept)
              .finalizeForwardDeclaration();