spirv-opt: Fix crash if shader uses linkage decoration (KhronosGroup#6191)

As for some optimization pass, which will get all operands of decoration
and add these to type. We assume that these operands are always one
word. As for linkage attributes decoration, it's an error because one of
operand is literal string, that means that operand is variable length
word.

Author: GinShio

source/opt/type_manager.cpp

@@ -1067,7 +1067,11 @@ void TypeManager::AttachDecoration(const Instruction& inst, Type* type) {
       const auto count = inst.NumOperands();
       std::vector<uint32_t> data;
       for (uint32_t i = 1; i < count; ++i) {
-        data.push_back(inst.GetSingleWordOperand(i));
+        // LinkageAttributes has a literal string as an operand, which is a
+        // varible length word. We cannot assume that all operands are single
+        // word.
+        const Operand::OperandData& words = inst.GetOperand(i).words;
+        data.insert(data.end(), words.begin(), words.end());
       }
       type->AddDecoration(std::move(data));
     } break;

test/opt/type_manager_test.cpp

@@ -1248,6 +1248,35 @@ TEST(TypeManager, CircularPointerToStruct) {
   EXPECT_EQ(id, 1201);
 }
 
+TEST(TypeManager, AttachLinkageDecoration) {
+  const std::string text = R"(
+      OpCapability Shader
+      OpCapability Linkage
+      OpMemoryModel Logical GLSL450
+      OpDecorate %1000 LinkageAttributes "_1000" Export
+       %800 = OpTypeInt 32 0
+      %1000 = OpTypeStruct %800
+      %1200 = OpTypeStruct %800
+  )";
+
+  std::unique_ptr<IRContext> context =
+      BuildModule(SPV_ENV_UNIVERSAL_1_5, nullptr, text,
+                  SPV_TEXT_TO_BINARY_OPTION_PRESERVE_NUMERIC_IDS);
+  TypeManager manager(nullptr, context.get());
+
+  constexpr uint32_t source_id = 1000u;
+  constexpr uint32_t target_id = 1200u;
+  std::vector<Instruction*> decorations =
+      context->get_decoration_mgr()->GetDecorationsFor(source_id, true);
+  Type* type = context->get_type_mgr()->GetType(target_id);
+  for (auto dec : decorations) {
+    manager.AttachDecoration(*dec, type);
+  }
+  EXPECT_FALSE(type->decoration_empty());
+  EXPECT_TRUE(
+      type->HasSameDecorations(context->get_type_mgr()->GetType(source_id)));
+}
+
 }  // namespace
 }  // namespace analysis
 }  // namespace opt