Get real value for typeAdapter (#6762)

* Get real value for typeAdapter

When the type is mismatch and typeAdapter is used, get the real value
from typeAdapter so that we don't get nullptr for irValue.

This fixes the assert if uint is used for SV_VertexID, which is an int
in the system binding semantic.

Fixes: #6525

* Add test case; add nullptr check

1 files changed, 9 insertions, 0 deletions

diff --git a/source/slang/slang-ir-glsl-legalize.cpp b/source/slang/slang-ir-glsl-legalize.cpp
index 455c924ca..802fc1eb4 100644
--- a/source/slang/slang-ir-glsl-legalize.cpp
+++ b/source/slang/slang-ir-glsl-legalize.cpp
@@ -3541,6 +3541,15 @@ void legalizeEntryPointParameterForGLSL(
                         if (elem.key == key)
                         {
                             realGlobalVar = elem.val.irValue;
+                            if (!realGlobalVar &&
+                                ScalarizedVal::Flavor::typeAdapter == elem.val.flavor)
+                            {
+                                if (auto typeAdapterVal =
+                                        as<ScalarizedTypeAdapterValImpl>(elem.val.impl))
+                                {
+                                    realGlobalVar = typeAdapterVal->val.irValue;
+                                }
+                            }
                             break;
                         }
                     }