Validate sign of int types. (#2549)

Fixes https://crbug.com/959011.

source/val/validate_type.cpp

diff --git a/source/val/validate_type.cpp b/source/val/validate_type.cpp
index ad72a37..edfede8 100644
--- a/source/val/validate_type.cpp
+++ b/source/val/validate_type.cpp
@@ -14,11 +14,10 @@
 
 // Ensures type declarations are unique unless allowed by the specification.
 
-#include "source/val/validate.h"
-
 #include "source/opcode.h"
 #include "source/spirv_target_env.h"
 #include "source/val/instruction.h"
+#include "source/val/validate.h"
 #include "source/val/validation_state.h"
 
 namespace spvtools {
@@ -67,6 +66,16 @@
   return SPV_SUCCESS;
 }
 
+spv_result_t ValidateTypeInt(ValidationState_t& _, const Instruction* inst) {
+  const auto signedness_index = 2;
+  const auto signedness = inst->GetOperandAs<uint32_t>(signedness_index);
+  if (signedness != 0 && signedness != 1) {
+    return _.diag(SPV_ERROR_INVALID_VALUE, inst)
+           << "OpTypeInt has invalid signedness:";
+  }
+  return SPV_SUCCESS;
+}
+
 spv_result_t ValidateTypeVector(ValidationState_t& _, const Instruction* inst) {
   const auto component_index = 1;
   const auto component_id = inst->GetOperandAs<uint32_t>(component_index);
@@ -439,6 +448,9 @@
   if (auto error = ValidateUniqueness(_, inst)) return error;
 
   switch (inst->opcode()) {
+    case SpvOpTypeInt:
+      if (auto error = ValidateTypeInt(_, inst)) return error;
+      break;
     case SpvOpTypeVector:
       if (auto error = ValidateTypeVector(_, inst)) return error;
       break;

test/val/val_literals_test.cpp

diff --git a/test/val/val_literals_test.cpp b/test/val/val_literals_test.cpp
index 4ef6186..6eadf32 100644
--- a/test/val/val_literals_test.cpp
+++ b/test/val/val_literals_test.cpp
@@ -85,6 +85,16 @@
   ASSERT_EQ(SPV_SUCCESS, ValidateInstructions());
 }
 
+TEST_F(ValidateLiterals, InvalidInt) {
+  std::string str = GenerateShaderCode() + R"(
+%11 = OpTypeInt 32 90
+  )";
+  CompileSuccessfully(str);
+  EXPECT_EQ(SPV_ERROR_INVALID_VALUE, ValidateInstructions());
+  EXPECT_THAT(getDiagnosticString(),
+              HasSubstr("OpTypeInt has invalid signedness:"));
+}
+
 TEST_P(ValidateLiteralsShader, LiteralsShaderBad) {
   std::string str = GenerateShaderCode() + GetParam();
   std::string inst_id = "11";