From 0c15582efcec6c7b163ae3a20c04e1aee958d24a Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Mon, 12 Feb 2024 13:19:35 -0800
Subject: Fix lowering of static consts in a generic function. (#3573)

* Fix lowering of static consts in a generic function.

* Fix.

* Fix.

* Fix lowering of shading rate builtin.
---
 source/slang/slang-ir-glsl-legalize.cpp |  9 ++++-
 source/slang/slang-lower-to-ir.cpp      | 69 +++++++++++++++++----------------
 2 files changed, 43 insertions(+), 35 deletions(-)

(limited to 'source')

diff --git a/source/slang/slang-ir-glsl-legalize.cpp b/source/slang/slang-ir-glsl-legalize.cpp
index dd165769c..0f9e88d20 100644
--- a/source/slang/slang-ir-glsl-legalize.cpp
+++ b/source/slang/slang-ir-glsl-legalize.cpp
@@ -929,7 +929,14 @@ GLSLSystemValueInfo* getGLSLSystemValueInfo(
     }
     else if (semanticName == "sv_shadingrate")
     {
-        name = "gl_PrimitiveShadingRateEXT";
+        if (kind == LayoutResourceKind::VaryingInput)
+        {
+            name = "gl_ShadingRateEXT";
+        }
+        else
+        {
+            name = "gl_PrimitiveShadingRateEXT";
+        }
     }
 
     if( name )
diff --git a/source/slang/slang-lower-to-ir.cpp b/source/slang/slang-lower-to-ir.cpp
index f5d743bb1..8fef6f535 100644
--- a/source/slang/slang-lower-to-ir.cpp
+++ b/source/slang/slang-lower-to-ir.cpp
@@ -724,6 +724,31 @@ LoweredValInfo emitDeclRef(
     DeclRef<Decl>   declRef,
     IRType*         type);
 
+
+bool isFunctionVarDecl(VarDeclBase* decl)
+{
+    // The immediate parent of a function-scope variable
+    // declaration will be a `ScopeDecl`.
+    //
+    // TODO: right now the parent links for scopes are *not*
+    // set correctly, so we can't just scan up and look
+    // for a function in the parent chain...
+    auto parent = decl->parentDecl;
+    if (as<ScopeDecl>(parent))
+    {
+        return true;
+    }
+    return false;
+}
+
+bool isFunctionStaticVarDecl(VarDeclBase* decl)
+{
+    // Only a variable marked `static` can be static.
+    if (!decl->findModifier<HLSLStaticModifier>())
+        return false;
+    return isFunctionVarDecl(decl);
+}
+
 IRInst* getSimpleVal(IRGenContext* context, LoweredValInfo lowered);
 
 int32_t getIntrinsicOp(
@@ -7439,25 +7464,22 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         NestedContext nested(this);
         auto subBuilder = nested.getBuilder();
         auto subContext = nested.getContext();
-        IRGeneric* outerGeneric = emitOuterGenerics(subContext, decl, decl);
 
-        // TODO(JS): Is this right? 
-        //
-        // If we *are* in a generic, then outputting this in the (current) generic scope would be correct.
-        // If we *aren't* we want to go the level above for insertion
-        //
-        // Just inserting into the parent doesn't work with a generic that holds a function that has a static const
-        // variable.
-        // 
+        IRGeneric* outerGeneric = nullptr;
+
+        // If we are static, then we need to insert the declaration before the parent.
         // This tries to match the behavior of previous `lowerFunctionStaticConstVarDecl` functionality
-        if (!outerGeneric && isFunctionStaticVarDecl(decl))
+        if (isFunctionStaticVarDecl(decl))
         {
             // We need to insert the constant at a level above
             // the function being emitted. This will usually
             // be the global scope, but it might be an outer
             // generic if we are lowering a generic function.
-
-            subBuilder->setInsertInto(subBuilder->getFunc()->getParent());
+            subBuilder->setInsertBefore(subBuilder->getFunc());
+        }
+        else if (!isFunctionVarDecl(decl))
+        {
+            outerGeneric = emitOuterGenerics(subContext, decl, decl);
         }
 
         auto initExpr = decl->initExpr;
@@ -7613,27 +7635,6 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         return globalVal;
     }
 
-    bool isFunctionStaticVarDecl(VarDeclBase* decl)
-    {
-        // Only a variable marked `static` can be static.
-        if(!decl->findModifier<HLSLStaticModifier>())
-            return false;
-
-        // The immediate parent of a function-scope variable
-        // declaration will be a `ScopeDecl`.
-        //
-        // TODO: right now the parent links for scopes are *not*
-        // set correctly, so we can't just scan up and look
-        // for a function in the parent chain...
-        auto parent = decl->parentDecl;
-        if( as<ScopeDecl>(parent) )
-        {
-            return true;
-        }
-
-        return false;
-    }
-
     struct NestedContext
     {
         IRGenEnv        subEnvStorage;
@@ -9782,7 +9783,7 @@ bool canDeclLowerToAGeneric(Decl* decl)
     {
         if (varDecl->hasModifier<HLSLStaticModifier>() && varDecl->hasModifier<ConstModifier>())
         {
-            return true;
+            return !isFunctionVarDecl(varDecl);
         }
     }
     
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