Do not zero-initialize groupshared and rayquery variables (#4838)

* Do not zero-initialize groupshared and rayquery variables

Fixes: #4824

`-zero-initialize` option will explicitly not:
1. Set any groupshared values to defaults
2. Set any rayQuery object to a default state (currently invalid code generation)

* grammer

* disallow groupshared initializers

disallow groupshared initializers & adjust tests accordingly

* remove disallowed groupshared-init expression

* do not default init if non-copyable

---------

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

2 files changed, 54 insertions, 0 deletions

diff --git a/source/slang/slang-check-decl.cpp b/source/slang/slang-check-decl.cpp
index 7211565dd..2e5e13360 100644
--- a/source/slang/slang-check-decl.cpp
+++ b/source/slang/slang-check-decl.cpp
@@ -1922,10 +1922,59 @@ namespace Slang
         checkVisibility(classDecl);
     }
 
+    bool DiagnoseIsAllowedInitExpr(VarDeclBase* varDecl, DiagnosticSink* sink)
+    {
+        // find groupshared modifier
+        if (varDecl->findModifier<HLSLGroupSharedModifier>())
+        {
+            if (sink && varDecl->initExpr)
+                sink->diagnose(varDecl, Diagnostics::cannotHaveInitializer, varDecl, "groupshared");
+            return false;
+        }
+
+        return true;
+    }
+
+    bool isDefaultInitializable(VarDeclBase* varDecl)
+    {
+        if (!DiagnoseIsAllowedInitExpr(varDecl, nullptr))
+            return false;
+
+        // Find struct and modifiers associated with varDecl
+        StructDecl* structDecl = as<StructDecl>(varDecl);
+        if (auto declRefType = as<DeclRefType>(varDecl->getType()))
+        {
+            if (auto genericAppRefDecl = as<GenericAppDeclRef>(declRefType->getDeclRefBase()))
+            {
+                auto baseGenericRefType = genericAppRefDecl->getBase()->getDecl();
+                if (auto baseTypeStruct = as<StructDecl>(baseGenericRefType))
+                {
+                    structDecl = baseTypeStruct;
+                }
+                else if (auto genericDecl = as<GenericDecl>(baseGenericRefType))
+                {
+                    if(auto innerTypeStruct = as<StructDecl>(genericDecl->inner))
+                        structDecl = innerTypeStruct;
+                }
+            }
+        }
+        if (structDecl)
+        {
+            // find if a type is non-copyable
+            if (structDecl->findModifier<NonCopyableTypeAttribute>())
+                return false;
+        }
+
+        return true;
+    }
+
     static Expr* constructDefaultInitExprForVar(SemanticsVisitor* visitor, VarDeclBase* varDecl)
     {
         if (!varDecl->type || !varDecl->type.type)
             return nullptr;
+        
+        if (!isDefaultInitializable(varDecl))
+            return nullptr;
 
         ConstructorDecl* defaultCtor = nullptr;
         auto declRefType = as<DeclRefType>(varDecl->type.type);
@@ -1951,8 +2000,11 @@ namespace Slang
             return defaultCall;
         }
     }
+
     void SemanticsDeclBodyVisitor::checkVarDeclCommon(VarDeclBase* varDecl)
     {
+        DiagnoseIsAllowedInitExpr(varDecl, getSink());
+
         // if zero initialize is true, set everything to a default
         if (getOptionSet().hasOption(CompilerOptionName::ZeroInitialize) 
             && !varDecl->initExpr
diff --git a/source/slang/slang-diagnostic-defs.h b/source/slang/slang-diagnostic-defs.h
index 44e8aa13d..03e8efbc0 100644
--- a/source/slang/slang-diagnostic-defs.h
+++ b/source/slang/slang-diagnostic-defs.h
@@ -520,6 +520,8 @@ DIAGNOSTIC(30504, Error, cannotUseInitializerListForType, "cannot use initialize
 // 3062x: variables
 DIAGNOSTIC(30620, Error, varWithoutTypeMustHaveInitializer, "a variable declaration without an initial-value expression must be given an explicit type")
 DIAGNOSTIC(30622, Error, ambiguousDefaultInitializerForType, "more than one default initializer was found for type '$0'")
+DIAGNOSTIC(30623, Error, cannotHaveInitializer, "'$0' cannot have an initializer because it is $1")
+
 
 // 307xx: parameters
 DIAGNOSTIC(30700, Error, outputParameterCannotHaveDefaultValue, "an 'out' or 'inout' parameter cannot have a default-value expression")