Fix metadata of register space and varying params. (#5906)

5 files changed, 69 insertions, 33 deletions

diff --git a/examples/reflection-api/README.md b/examples/reflection-api/README.md
index 9dc5f1745..f37ec4b69 100644
--- a/examples/reflection-api/README.md
+++ b/examples/reflection-api/README.md
@@ -4,3 +4,6 @@ Slang Reflection API Example
 This example shows basic usage of the Slang reflection API to
 traverse the parameters of a program, including type and
 layout information.
+
+This example is a companion Slang reflection API documentation:
+https://shader-slang.org/slang/user-guide/compiling.html
diff --git a/examples/reflection-api/main.cpp b/examples/reflection-api/main.cpp
index 9d773fffd..5c157b797 100644
--- a/examples/reflection-api/main.cpp
+++ b/examples/reflection-api/main.cpp
@@ -7,9 +7,8 @@
 // This example uses the Slang reflection API to travserse the structure
 // of the parameters of a Slang program and their types.
 //
-// This program is a companion to a document on the Slang reflection API.
-// Once that document is published, this paragraph will be updated to
-// properly link to that document.
+// This program is a companion Slang reflection API documentation:
+// https://shader-slang.org/slang/user-guide/compiling.html
 //
 // Boilerplate
 // -----------
diff --git a/source/compiler-core/slang-artifact-associated-impl.h b/source/compiler-core/slang-artifact-associated-impl.h
index 8a89f865b..0418b2018 100644
--- a/source/compiler-core/slang-artifact-associated-impl.h
+++ b/source/compiler-core/slang-artifact-associated-impl.h
@@ -163,6 +163,9 @@ struct ShaderBindingRange
         case slang::UnorderedAccess:
         case slang::SamplerState:
         case slang::DescriptorTableSlot:
+        case slang::VaryingInput:
+        case slang::VaryingOutput:
+        case slang::SpecializationConstant:
             return true;
         default:
             return false;
diff --git a/source/slang/slang-ir-metadata.cpp b/source/slang/slang-ir-metadata.cpp
index 7f0c82471..7348c06fd 100644
--- a/source/slang/slang-ir-metadata.cpp
+++ b/source/slang/slang-ir-metadata.cpp
@@ -43,6 +43,41 @@ static void _insertBinding(
     ranges.add(newRange);
 }
 
+void collectMetadataFromInst(IRInst* param, ArtifactPostEmitMetadata& outMetadata)
+{
+    auto layoutDecoration = param->findDecoration<IRLayoutDecoration>();
+    if (!layoutDecoration)
+        return;
+
+    auto varLayout = as<IRVarLayout>(layoutDecoration->getLayout());
+    if (!varLayout)
+        return;
+
+    for (auto sizeAttr : varLayout->getTypeLayout()->getSizeAttrs())
+    {
+        auto kind = sizeAttr->getResourceKind();
+
+        // Only track resource types that we can reliably track, such as textures.
+        // Do not track individual uniforms, for example.
+        if (!ShaderBindingRange::isUsageTracked(kind))
+            continue;
+
+        if (auto offsetAttr = varLayout->findOffsetAttr(kind))
+        {
+            // Get the binding information from this attribute and insert it into the list
+            auto spaceIndex = offsetAttr->getSpace();
+            if (auto spaceAttr = varLayout->findOffsetAttr(LayoutResourceKind::RegisterSpace))
+            {
+                spaceIndex += spaceAttr->getOffset();
+            }
+            auto registerIndex = offsetAttr->getOffset();
+            auto size = sizeAttr->getSize();
+            auto count = size.isFinite() ? size.getFiniteValue() : 0;
+            _insertBinding(outMetadata.m_usedBindings, kind, spaceIndex, registerIndex, count);
+        }
+    }
+}
+
 // Collects the metadata from the provided IR module, saves it in outMetadata.
 void collectMetadata(const IRModule* irModule, ArtifactPostEmitMetadata& outMetadata)
 {
@@ -57,39 +92,18 @@ void collectMetadata(const IRModule* irModule, ArtifactPostEmitMetadata& outMeta
                 auto name = func->findDecoration<IRExportDecoration>()->getMangledName();
                 outMetadata.m_exportedFunctionMangledNames.add(name);
             }
+
+            // Collect metadata from entrypoint params.
+            for (auto param : func->getParams())
+            {
+                collectMetadataFromInst(param, outMetadata);
+            }
         }
 
         auto param = as<IRGlobalParam>(inst);
         if (!param)
             continue;
-
-        auto layoutDecoration = param->findDecoration<IRLayoutDecoration>();
-        if (!layoutDecoration)
-            continue;
-
-        auto varLayout = as<IRVarLayout>(layoutDecoration->getLayout());
-        if (!varLayout)
-            continue;
-
-        for (auto sizeAttr : varLayout->getTypeLayout()->getSizeAttrs())
-        {
-            auto kind = sizeAttr->getResourceKind();
-
-            // Only track resource types that we can reliably track, such as textures.
-            // Do not track individual uniforms, for example.
-            if (!ShaderBindingRange::isUsageTracked(kind))
-                continue;
-
-            if (auto offsetAttr = varLayout->findOffsetAttr(kind))
-            {
-                // Get the binding information from this attribute and insert it into the list
-                auto spaceIndex = offsetAttr->getSpace();
-                auto registerIndex = offsetAttr->getOffset();
-                auto size = sizeAttr->getSize();
-                auto count = size.isFinite() ? size.getFiniteValue() : 0;
-                _insertBinding(outMetadata.m_usedBindings, kind, spaceIndex, registerIndex, count);
-            }
-        }
+        collectMetadataFromInst(param, outMetadata);
     }
 }
 
diff --git a/tools/slang-unit-test/unit-test-parameter-usage-reflection.cpp b/tools/slang-unit-test/unit-test-parameter-usage-reflection.cpp
index ce9df5a42..e4a89a277 100644
--- a/tools/slang-unit-test/unit-test-parameter-usage-reflection.cpp
+++ b/tools/slang-unit-test/unit-test-parameter-usage-reflection.cpp
@@ -18,10 +18,15 @@ SLANG_UNIT_TEST(isParameterLocationUsedReflection)
     // Source for a module that contains an undecorated entrypoint.
     const char* userSourceBody = R"(
         Texture2D g_tex : register(t0);
+        struct Params {
+            Texture2D tex2;
+            Texture2D tex3;
+        };
+        ParameterBlock<Params> gParams;
         [shader("fragment")]
-        float4 fragMain(float4 pos:SV_Position) : SV_Target
+        float4 fragMain(float4 pos:SV_Position, float unused:COLOR0, float4 used:COLOR1) : SV_Target
         {
-            return g_tex.Load(int3(0, 0, 0));
+            return g_tex.Load(int3(0, 0, 0)) + gParams.tex3.Load(int3(0)) + used;
         }
         )";
 
@@ -75,4 +80,16 @@ SLANG_UNIT_TEST(isParameterLocationUsedReflection)
 
     metadata->isParameterLocationUsed(SLANG_PARAMETER_CATEGORY_DESCRIPTOR_TABLE_SLOT, 0, 1, isUsed);
     SLANG_CHECK(!isUsed);
+
+    metadata->isParameterLocationUsed(SLANG_PARAMETER_CATEGORY_DESCRIPTOR_TABLE_SLOT, 1, 0, isUsed);
+    SLANG_CHECK(!isUsed);
+
+    metadata->isParameterLocationUsed(SLANG_PARAMETER_CATEGORY_DESCRIPTOR_TABLE_SLOT, 1, 1, isUsed);
+    SLANG_CHECK(isUsed);
+
+    metadata->isParameterLocationUsed(SLANG_PARAMETER_CATEGORY_VARYING_INPUT, 0, 0, isUsed);
+    SLANG_CHECK(!isUsed);
+
+    metadata->isParameterLocationUsed(SLANG_PARAMETER_CATEGORY_VARYING_INPUT, 0, 1, isUsed);
+    SLANG_CHECK(isUsed);
 }