[SemaHLSL] Correct descriptor range overflow validation

clang/lib/Sema/SemaHLSL.cpp

@@ -1361,6 +1361,7 @@ bool SemaHLSL::handleRootSignatureElements(
       bool HasAnySampler = false;
       bool HasAnyNonSampler = false;
       uint32_t Offset = 0;
+      bool Unbound = false;
       for (const auto &[Clause, ClauseElem] : UnboundClauses) {
         SourceLocation Loc = ClauseElem->getLocation();
         if (Clause->Type == llvm::dxil::ResourceClass::Sampler)
@@ -1381,22 +1382,24 @@ bool SemaHLSL::handleRootSignatureElements(
             llvm::hlsl::rootsig::DescriptorTableOffsetAppend) {
           // Manually specified the offset
           Offset = Clause->Offset;
+        } else if (Unbound) {
+          // Trying to append onto unbound offset
+          Diag(Loc, diag::err_hlsl_appending_onto_unbound);
         }
 
         uint64_t RangeBound = llvm::hlsl::rootsig::computeRangeBound(
             Offset, Clause->NumDescriptors);
 
-        if (!llvm::hlsl::rootsig::verifyBoundOffset(Offset)) {
-          // Trying to append onto unbound offset
-          Diag(Loc, diag::err_hlsl_appending_onto_unbound);
-        } else if (!llvm::hlsl::rootsig::verifyNoOverflowedOffset(RangeBound)) {
+        if (!llvm::hlsl::rootsig::verifyNoOverflowedOffset(RangeBound)) {
           // Upper bound overflows maximum offset
           Diag(Loc, diag::err_hlsl_offset_overflow) << Offset << RangeBound;
         }
 
         Offset = RangeBound == llvm::hlsl::rootsig::NumDescriptorsUnbounded
                      ? uint32_t(RangeBound)
                      : uint32_t(RangeBound + 1);
+        Unbound = Clause->NumDescriptors ==
+                  llvm::hlsl::rootsig::NumDescriptorsUnbounded;
 
         // Compute the register bounds and track resource binding
         uint32_t LowerBound(Clause->Reg.Number);

clang/test/SemaHLSL/RootSignature-resource-ranges-err.hlsl

@@ -141,4 +141,8 @@ void append_offset_overflow_signature() {}
 
 // expected-error@+1 {{descriptor range offset overflows [4294967292, 4294967296]}}
 [RootSignature("DescriptorTable(CBV(b0, offset = 4294967292, numDescriptors = 5))")]
-void offset_() {}
+void offset_overflow() {}
+
+// expected-error@+1 {{descriptor range offset overflows [4294967295, 4294967296]}}
+[RootSignature("DescriptorTable(CBV(b0, offset = 4294967294), CBV(b1, numDescriptors = 2))")]
+void appended_offset_overflow() {}

clang/test/SemaHLSL/RootSignature-resource-ranges.hlsl

@@ -25,3 +25,6 @@ void valid_root_signature_6() {}
 
 [RootSignature("DescriptorTable(CBV(b0, offset = 4294967292), CBV(b1, numDescriptors = 3))")]
 void valid_root_signature_7() {}
+
+[RootSignature("DescriptorTable(CBV(b0, offset = 4294967294), CBV(b1))")]
+void valid_root_signature_8() {}

llvm/include/llvm/Frontend/HLSL/RootSignatureValidations.h

@@ -38,7 +38,6 @@ LLVM_ABI bool verifyMipLODBias(float MipLODBias);
 LLVM_ABI bool verifyMaxAnisotropy(uint32_t MaxAnisotropy);
 LLVM_ABI bool verifyLOD(float LOD);
 
-LLVM_ABI bool verifyBoundOffset(uint32_t Offset);
 LLVM_ABI bool verifyNoOverflowedOffset(uint64_t Offset);
 LLVM_ABI uint64_t computeRangeBound(uint32_t Offset, uint32_t Size);
 

llvm/lib/Frontend/HLSL/RootSignatureValidations.cpp

@@ -125,10 +125,6 @@ bool verifyMaxAnisotropy(uint32_t MaxAnisotropy) {
 
 bool verifyLOD(float LOD) { return !std::isnan(LOD); }
 
-bool verifyBoundOffset(uint32_t Offset) {
-  return Offset != NumDescriptorsUnbounded;
-}
-
 bool verifyNoOverflowedOffset(uint64_t Offset) {
   return Offset <= std::numeric_limits<uint32_t>::max();
 }