add basic integer range validations

Author: inbelic

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -13077,6 +13077,8 @@ def err_invalid_hlsl_resource_type: Error<
 def err_hlsl_spirv_only: Error<"%0 is only available for the SPIR-V target">;
 def err_hlsl_vk_literal_must_contain_constant: Error<"the argument to vk::Literal must be a vk::integral_constant">;
 
+def err_hlsl_invalid_rootsig_value : Error<"value must be in the range [%0, %1]">;
+
 def subst_hlsl_format_ranges: TextSubstitution<
   "%select{t|u|b|s}0[%1;%select{%3]|unbounded)}2">;
 

clang/lib/Sema/SemaHLSL.cpp

@@ -44,6 +44,7 @@
 #include "llvm/Support/DXILABI.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/TargetParser/Triple.h"
+#include <cmath>
 #include <cstddef>
 #include <iterator>
 #include <utility>
@@ -1083,6 +1084,63 @@ void SemaHLSL::ActOnFinishRootSignatureDecl(
 
 bool SemaHLSL::handleRootSignatureElements(
     ArrayRef<hlsl::RootSignatureElement> Elements) {
+  // Define some common error handling functions
+  bool HadError = false;
+  auto ReportError = [this, &HadError](SourceLocation Loc, uint32_t LowerBound,
+                                       uint32_t UpperBound) {
+    HadError = true;
+    this->Diag(Loc, diag::err_hlsl_invalid_rootsig_value)
+        << LowerBound << UpperBound;
+  };
+
+  auto VerifyRegister = [ReportError](SourceLocation Loc, uint32_t Register) {
+    if (!llvm::hlsl::rootsig::verifyRegisterValue(Register))
+      ReportError(Loc, 0, 0xfffffffe);
+  };
+
+  auto VerifySpace = [ReportError](SourceLocation Loc, uint32_t Space) {
+    if (!llvm::hlsl::rootsig::verifyRegisterSpace(Space))
+      ReportError(Loc, 0, 0xffffffef);
+  };
+
+  // Iterate through the elements and do basic validations
+  for (const hlsl::RootSignatureElement &RootSigElem : Elements) {
+    SourceLocation Loc = RootSigElem.getLocation();
+    const llvm::hlsl::rootsig::RootElement &Elem = RootSigElem.getElement();
+    if (const auto *Descriptor =
+            std::get_if<llvm::hlsl::rootsig::RootDescriptor>(&Elem)) {
+      VerifyRegister(Loc, Descriptor->Reg.Number);
+      VerifySpace(Loc, Descriptor->Space);
+    } else if (const auto *Constants =
+                   std::get_if<llvm::hlsl::rootsig::RootConstants>(&Elem)) {
+      VerifyRegister(Loc, Constants->Reg.Number);
+      VerifySpace(Loc, Constants->Space);
+    } else if (const auto *Sampler =
+                   std::get_if<llvm::hlsl::rootsig::StaticSampler>(&Elem)) {
+      VerifyRegister(Loc, Sampler->Reg.Number);
+      VerifySpace(Loc, Sampler->Space);
+
+      assert(!std::isnan(Sampler->MaxLOD) && !std::isnan(Sampler->MinLOD) &&
+             "By construction, parseFloatParam can't produce a NaN from a "
+             "float_literal token");
+
+      if (16 < Sampler->MaxAnisotropy)
+        ReportError(Loc, 0, 16);
+    } else if (const auto *Clause =
+                   std::get_if<llvm::hlsl::rootsig::DescriptorTableClause>(
+                       &Elem)) {
+      VerifyRegister(Loc, Clause->Reg.Number);
+      VerifySpace(Loc, Clause->Space);
+
+      if (!llvm::hlsl::rootsig::verifyNumDescriptors(Clause->NumDescriptors)) {
+        // NumDescriptor could techincally be ~0u but that is reserved for
+        // unbounded, so the diagnostic will not report that as a valid int
+        // value
+        ReportError(Loc, 1, 0xfffffffe);
+      }
+    }
+  }
+
   using RangeInfo = llvm::hlsl::rootsig::RangeInfo;
   using OverlappingRanges = llvm::hlsl::rootsig::OverlappingRanges;
 
@@ -1136,7 +1194,10 @@ bool SemaHLSL::handleRootSignatureElements(
                        &Elem)) {
       RangeInfo Info;
       Info.LowerBound = Clause->Reg.Number;
-      assert(0 < Clause->NumDescriptors && "Verified as part of TODO(#129940)");
+      // Relevant error will have already been reported above and needs to be
+      // fixed before we can conduct range analysis, so shortcut error return
+      if (Clause->NumDescriptors == 0)
+        return true;
       Info.UpperBound = Clause->NumDescriptors == RangeInfo::Unbounded
                             ? RangeInfo::Unbounded
                             : Info.LowerBound + Clause->NumDescriptors -

clang/test/SemaHLSL/RootSignature-err.hlsl

@@ -38,3 +38,34 @@ void bad_root_signature_6() {}
 // expected-error@+1 {{expected end of stream to denote end of parameters, or, another valid parameter of RootSignature}}
 [RootSignature("RootFlags() RootConstants(b0, num32BitConstants = 1))")]
 void bad_root_signature_7() {}
+
+// Basic validation of register value and space
+
+// expected-error@+2 {{value must be in the range [0, 4294967294]}}
+// expected-error@+1 {{value must be in the range [0, 4294967279]}}
+[RootSignature("CBV(b4294967295, space = 4294967280)")]
+void basic_validation_0() {}
+
+// expected-error@+2 {{value must be in the range [0, 4294967294]}}
+// expected-error@+1 {{value must be in the range [0, 4294967279]}}
+[RootSignature("RootConstants(b4294967295, space = 4294967280, num32BitConstants = 1)")]
+void basic_validation_1() {}
+
+// expected-error@+2 {{value must be in the range [0, 4294967294]}}
+// expected-error@+1 {{value must be in the range [0, 4294967279]}}
+[RootSignature("StaticSampler(s4294967295, space = 4294967280)")]
+void basic_validation_2() {}
+
+// expected-error@+2 {{value must be in the range [0, 4294967294]}}
+// expected-error@+1 {{value must be in the range [0, 4294967279]}}
+[RootSignature("DescriptorTable(SRV(t4294967295, space = 4294967280))")]
+void basic_validation_3() {}
+
+// expected-error@+2 {{value must be in the range [1, 4294967294]}}
+// expected-error@+1 {{value must be in the range [1, 4294967294]}}
+[RootSignature("DescriptorTable(UAV(u0, numDescriptors = 0), Sampler(s0, numDescriptors = 0))")]
+void basic_validation_4() {}
+
+// expected-error@+1 {{value must be in the range [0, 16]}}
+[RootSignature("StaticSampler(s0, maxAnisotropy = 17, mipLODBias = -16.000001)")]
+void basic_validation_5() {}