spirv-val: SBT Index for OpExecuteCallableKHR (#4900)

source/val/validate_ray_tracing.cpp

diff --git a/source/val/validate_ray_tracing.cpp b/source/val/validate_ray_tracing.cpp
index 81fa593..78bac19 100644
--- a/source/val/validate_ray_tracing.cpp
+++ b/source/val/validate_ray_tracing.cpp
@@ -174,6 +174,13 @@
             return true;
           });
 
+      const uint32_t sbt_index = _.GetOperandTypeId(inst, 0);
+      if (!_.IsUnsignedIntScalarType(sbt_index) ||
+          _.GetBitWidth(sbt_index) != 32) {
+        return _.diag(SPV_ERROR_INVALID_DATA, inst)
+               << "SBT Index must be a 32-bit unsigned int scalar";
+      }
+
       const auto callable_data = _.FindDef(inst->GetOperandAs<uint32_t>(1));
       if (callable_data->opcode() != SpvOpVariable) {
         return _.diag(SPV_ERROR_INVALID_DATA, inst)

test/val/val_ray_tracing.cpp

diff --git a/test/val/val_ray_tracing.cpp b/test/val/val_ray_tracing.cpp
index 9486777..58b9356 100644
--- a/test/val/val_ray_tracing.cpp
+++ b/test/val/val_ray_tracing.cpp
@@ -334,6 +334,34 @@
                         "or IncomingCallableDataKHR"));
 }
 
+TEST_F(ValidateRayTracing, ExecuteCallableSbtIndex) {
+  const std::string body = R"(
+OpCapability RayTracingKHR
+OpExtension "SPV_KHR_ray_tracing"
+OpMemoryModel Logical GLSL450
+OpEntryPoint CallableKHR %main "main"
+OpName %main "main"
+%void = OpTypeVoid
+%func = OpTypeFunction %void
+%int = OpTypeInt 32 1
+%uint = OpTypeInt 32 0
+%uint_0 = OpConstant %uint 0
+%int_1 = OpConstant %int 1
+%data_ptr = OpTypePointer CallableDataKHR %int
+%data = OpVariable %data_ptr CallableDataKHR
+%main = OpFunction %void None %func
+%label = OpLabel
+OpExecuteCallableKHR %int_1 %data
+OpReturn
+OpFunctionEnd
+)";
+
+  CompileSuccessfully(body.c_str());
+  EXPECT_EQ(SPV_ERROR_INVALID_DATA, ValidateInstructions());
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("SBT Index must be a 32-bit unsigned int scalar"));
+}
+
 std::string GenerateRayTraceCode(
     const std::string& body,
     const std::string execution_model = "RayGenerationKHR") {