[llvm-branch-commits] [clang] [HLSL] Add binding attributes to resources from structs (PR #184731)

[Helena Kotas via llvm-branch-commits]

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@@ -4448,13 +4475,99 @@ void SemaHLSL::deduceAddressSpace(VarDecl *Decl) {
 
 namespace {
 
+// Helper class for assigning bindings to resources declared within a struct.
+// It keeps track of all binding attributes declared on a struct instance, and
+// the offsets for each register type that have been assigned so far.
+// Handles both explicit and implicit bindings.
+class StructBindingContext {
+  // Bindings and offsets per register type. We only need to support four
+  // register types - SRV (u), UAV (t), CBuffer (c), and Sampler (s).
+  HLSLResourceBindingAttr *RegBindingsAttrs[4];
+  unsigned RegBindingOffset[4];
+
+  // Vulkan binding attribute does not vary by register type.
+  HLSLVkBindingAttr *VkBindingAttr;
+  unsigned VkBindingOffset;
+
+public:
+  // Constructor: gather all binding attributes on a struct instance and
+  // initialize offsets.
+  StructBindingContext(VarDecl *VD) {
+    for (unsigned i = 0; i < 4; ++i) {
+      RegBindingsAttrs[i] = nullptr;
+      RegBindingOffset[i] = 0;
+    }
+    VkBindingAttr = nullptr;
+    VkBindingOffset = 0;
+
+    ASTContext &AST = VD->getASTContext();
+    bool IsSpirv = AST.getTargetInfo().getTriple().isSPIRV();
+
+    for (Attr *A : VD->attrs()) {
+      if (auto *RBA = dyn_cast<HLSLResourceBindingAttr>(A)) {
+        RegisterType RegType = RBA->getRegisterType();
+        unsigned RegTypeIdx = static_cast<unsigned>(RegType);
+        // Ignore unsupported register annotations, such as 'c' or 'i'.
+        if (RegTypeIdx < 4)
+          RegBindingsAttrs[RegTypeIdx] = RBA;
+        continue;
+      }
+      // Gather the Vulkan binding attributes only if the target is SPIR-V.
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hekota wrote:

No, we still need to collect those because if the target is SPIR-V, and there is no `HLSLVkBindingAttr` attribute, the compiler falls back to the `HLSLResourceBindingAttrs` values for the binding.

https://github.com/llvm/llvm-project/pull/184731