1 files changed, 16 insertions, 30 deletions

diff --git a/clang/lib/CodeGen/CGHLSLRuntime.cpp b/clang/lib/CodeGen/CGHLSLRuntime.cpp
index e392a12..4bdba9b 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.cpp
+++ b/clang/lib/CodeGen/CGHLSLRuntime.cpp
@@ -261,12 +261,12 @@ static std::optional<llvm::Value *> initializeLocalResourceArray(
 
 llvm::Type *
 CGHLSLRuntime::convertHLSLSpecificType(const Type *T,
-                                       SmallVector<int32_t> *Packoffsets) {
+                                       const CGHLSLOffsetInfo &OffsetInfo) {
   assert(T->isHLSLSpecificType() && "Not an HLSL specific type!");
 
   // Check if the target has a specific translation for this type first.
   if (llvm::Type *TargetTy =
-          CGM.getTargetCodeGenInfo().getHLSLType(CGM, T, Packoffsets))
+          CGM.getTargetCodeGenInfo().getHLSLType(CGM, T, OffsetInfo))
     return TargetTy;
 
   llvm_unreachable("Generic handling of HLSL types is not supported.");
@@ -357,25 +357,14 @@ createBufferHandleType(const HLSLBufferDecl *BufDecl) {
   return cast<HLSLAttributedResourceType>(QT.getTypePtr());
 }
 
-// Iterates over all declarations in the HLSL buffer and based on the
-// packoffset or register(c#) annotations it fills outs the Layout
-// vector with the user-specified layout offsets.
-// The buffer offsets can be specified 2 ways:
-// 1. declarations in cbuffer {} block can have a packoffset annotation
-//    (translates to HLSLPackOffsetAttr)
-// 2. default constant buffer declarations at global scope can have
-//    register(c#) annotations (translates to HLSLResourceBindingAttr with
-//    RegisterType::C)
-// It is not guaranteed that all declarations in a buffer have an annotation.
-// For those where it is not specified a -1 value is added to the Layout
-// vector. In the final layout these declarations will be placed at the end
-// of the HLSL buffer after all of the elements with specified offset.
-static void fillPackoffsetLayout(const HLSLBufferDecl *BufDecl,
-                                 SmallVector<int32_t> &Layout) {
-  assert(Layout.empty() && "expected empty vector for layout");
-  assert(BufDecl->hasValidPackoffset());
+CGHLSLOffsetInfo CGHLSLOffsetInfo::fromDecl(const HLSLBufferDecl &BufDecl) {
+  CGHLSLOffsetInfo Result;
 
-  for (Decl *D : BufDecl->buffer_decls()) {
+  // If we don't have packoffset info, just return an empty result.
+  if (!BufDecl.hasValidPackoffset())
+    return Result;
+
+  for (Decl *D : BufDecl.buffer_decls()) {
     if (isa<CXXRecordDecl, EmptyDecl>(D) || isa<FunctionDecl>(D)) {
       continue;
     }
@@ -384,11 +373,11 @@ static void fillPackoffsetLayout(const HLSLBufferDecl *BufDecl,
       continue;
 
     if (!VD->hasAttrs()) {
-      Layout.push_back(-1);
+      Result.Offsets.push_back(Unspecified);
       continue;
     }
 
-    int32_t Offset = -1;
+    uint32_t Offset = Unspecified;
     for (auto *Attr : VD->getAttrs()) {
       if (auto *POA = dyn_cast<HLSLPackOffsetAttr>(Attr)) {
         Offset = POA->getOffsetInBytes();
@@ -401,8 +390,9 @@ static void fillPackoffsetLayout(const HLSLBufferDecl *BufDecl,
         break;
       }
     }
-    Layout.push_back(Offset);
+    Result.Offsets.push_back(Offset);
   }
+  return Result;
 }
 
 // Codegen for HLSLBufferDecl
@@ -419,13 +409,9 @@ void CGHLSLRuntime::addBuffer(const HLSLBufferDecl *BufDecl) {
     return;
 
   // create global variable for the constant buffer
-  SmallVector<int32_t> Layout;
-  if (BufDecl->hasValidPackoffset())
-    fillPackoffsetLayout(BufDecl, Layout);
-
-  llvm::TargetExtType *TargetTy =
-      cast<llvm::TargetExtType>(convertHLSLSpecificType(
-          ResHandleTy, BufDecl->hasValidPackoffset() ? &Layout : nullptr));
+  CGHLSLOffsetInfo OffsetInfo = CGHLSLOffsetInfo::fromDecl(*BufDecl);
+  llvm::TargetExtType *TargetTy = cast<llvm::TargetExtType>(
+      convertHLSLSpecificType(ResHandleTy, OffsetInfo));
   llvm::GlobalVariable *BufGV = new GlobalVariable(
       TargetTy, /*isConstant*/ false,
       GlobalValue::LinkageTypes::ExternalLinkage, PoisonValue::get(TargetTy),