Allow Link time constant array length sizing, warn on unsupported functionality (#7067)

* Add link time array layout test

* Add link time constant array size compilation test

* Link time constant array size test

* Allow getting link time array size

Closes https://github.com/shader-slang/slang/issues/6753

* format

* Switch to SIMPLE test and check output

* Implement without binary api changes

* diagnose on link time constant sized array

* fix test

---------

Co-authored-by: Yong He <yonghe@outlook.com>

2 files changed, 18 insertions, 3 deletions

diff --git a/include/slang-deprecated.h b/include/slang-deprecated.h
index 2ae91c6d8..f210e8c48 100644
--- a/include/slang-deprecated.h
+++ b/include/slang-deprecated.h
@@ -478,9 +478,19 @@ extern "C"
 
     If the size of a type cannot be statically computed, perhaps because it depends on
     a generic parameter that has not been bound to a specific value, this function returns zero.
+
+    Use spReflectionType_GetSpecializedElementCount if the size is dependent on
+    a link time constant
     */
     SLANG_API size_t spReflectionType_GetElementCount(SlangReflectionType* type);
 
+    /** The same as spReflectionType_GetElementCount except it takes into account specialization
+     * information from the given reflection info
+     */
+    SLANG_API size_t spReflectionType_GetSpecializedElementCount(
+        SlangReflectionType* type,
+        SlangReflection* reflection);
+
     SLANG_API SlangReflectionType* spReflectionType_GetElementType(SlangReflectionType* type);
 
     SLANG_API unsigned int spReflectionType_GetRowCount(SlangReflectionType* type);
diff --git a/include/slang.h b/include/slang.h
index 782c4a082..4a3af7de1 100644
--- a/include/slang.h
+++ b/include/slang.h
@@ -2291,9 +2291,9 @@ struct TypeReflection
     }
 
     // only useful if `getKind() == Kind::Array`
-    size_t getElementCount()
+    size_t getElementCount(SlangReflection* reflection = nullptr)
     {
-        return spReflectionType_GetElementCount((SlangReflectionType*)this);
+        return spReflectionType_GetSpecializedElementCount((SlangReflectionType*)this, reflection);
     }
 
     size_t getTotalArrayElementCount()
@@ -2454,6 +2454,8 @@ enum class BindingType : SlangBindingTypeIntegral
     ExtMask = SLANG_BINDING_TYPE_EXT_MASK,
 };
 
+struct ShaderReflection;
+
 struct TypeLayoutReflection
 {
     TypeReflection* getType()
@@ -2543,7 +2545,10 @@ struct TypeLayoutReflection
     }
 
     // only useful if `getKind() == Kind::Array`
-    size_t getElementCount() { return getType()->getElementCount(); }
+    size_t getElementCount(ShaderReflection* reflection = nullptr)
+    {
+        return getType()->getElementCount((SlangReflection*)reflection);
+    }
 
     size_t getTotalArrayElementCount() { return getType()->getTotalArrayElementCount(); }