From ce879112cb16e3def1b8673104e7123b8b17ee2a Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Sun, 21 Jan 2018 07:09:55 -0500
Subject: Improvements and bug fixes for global type parameters

1. allow spReflection_FindTypeByName to accept arbitrary type expression string
2. allow const int generic value to be used as expression value, and as array size
3. various bug fixes in witness table specialization / function cloning during specializeIRForEntryPoint to avoid creating duplicate global values, not copying the right definition of a function from the other module, not cloning witness tables that are required by specializeGenerics etc.
---
 source/slang/lower-to-ir.cpp | 49 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 41 insertions(+), 8 deletions(-)

(limited to 'source/slang/lower-to-ir.cpp')

diff --git a/source/slang/lower-to-ir.cpp b/source/slang/lower-to-ir.cpp
index 5e7e05a23..5d710725a 100644
--- a/source/slang/lower-to-ir.cpp
+++ b/source/slang/lower-to-ir.cpp
@@ -1021,6 +1021,7 @@ RefPtr<IRFuncType> getFuncType(
     return funcType;
 }
 
+SubstitutionSet lowerSubstitutions(IRGenContext* context, SubstitutionSet subst);
 //
 
 struct ValLoweringVisitor : ValVisitor<ValLoweringVisitor, LoweredValInfo, LoweredTypeInfo>
@@ -1080,8 +1081,6 @@ struct ValLoweringVisitor : ValVisitor<ValLoweringVisitor, LoweredValInfo, Lower
         // TODO: actually test what module the type is coming from.
 
         lowerDecl(context, type->declRef);
-
-
         return LoweredTypeInfo(type);
     }
 
@@ -3006,6 +3005,11 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         return globalVal;
     }
 
+    LoweredValInfo visitGenericValueParamDecl(GenericValueParamDecl* decl)
+    {
+        return LoweredValInfo::simple(context->irBuilder->getDeclRefVal(DeclRefBase(decl)));
+    }
+
     LoweredValInfo visitVarDeclBase(VarDeclBase* decl)
     {
         // Detect global (or effectively global) variables
@@ -3733,7 +3737,10 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         if (auto innerFuncDecl = genDecl->inner->As<FuncDecl>())
             return lowerFuncDecl(innerFuncDecl);
         else if (auto innerStructDecl = genDecl->inner->As<StructDecl>())
+        {
+            visitAggTypeDecl(innerStructDecl);
             return LoweredValInfo();
+        }
         SLANG_RELEASE_ASSERT(false);
         UNREACHABLE_RETURN(LoweredValInfo());
     }
@@ -3910,6 +3917,32 @@ RefPtr<GenericSubstitution> lowerGenericSubstitutions(
     return result;
 }
 
+RefPtr<GlobalGenericParamSubstitution> lowerGlobalGenericSubstitutions(
+    IRGenContext*   context,
+    GlobalGenericParamSubstitution*  genSubst)
+{
+    if (!genSubst)
+        return nullptr;
+    RefPtr<GlobalGenericParamSubstitution> result;
+    RefPtr<GlobalGenericParamSubstitution> newSubst = new GlobalGenericParamSubstitution();
+    newSubst->actualType = lowerSubstitutionArg(context, genSubst->actualType);
+    newSubst->paramDecl = genSubst->paramDecl;
+    for (auto & tbl : genSubst->witnessTables)
+    {
+        auto ntbl = tbl;
+        ntbl.Value = lowerSubstitutionArg(context, tbl.Value);
+        newSubst->witnessTables.Add(ntbl);
+    }
+    result = newSubst;
+    if (genSubst->outer)
+    {
+        result->outer = lowerGlobalGenericSubstitutions(
+            context,
+            genSubst->outer);
+    }
+    return result;
+}
+
 RefPtr<ThisTypeSubstitution> lowerThisTypeSubstitution(
     IRGenContext*   context,
     ThisTypeSubstitution*  thisSubst)
@@ -3926,7 +3959,7 @@ SubstitutionSet lowerSubstitutions(IRGenContext* context, SubstitutionSet subst)
     SubstitutionSet rs;
     rs.genericSubstitutions = lowerGenericSubstitutions(context, subst.genericSubstitutions);
     rs.thisTypeSubstitution = lowerThisTypeSubstitution(context, subst.thisTypeSubstitution);
-    rs.globalGenParamSubstitutions = subst.globalGenParamSubstitutions;
+    rs.globalGenParamSubstitutions = lowerGlobalGenericSubstitutions(context, subst.globalGenParamSubstitutions);
     return rs;
 }
 
@@ -3973,10 +4006,10 @@ LoweredValInfo maybeEmitSpecializeInst(IRGenContext*   context,
     // need to walk through those and replace things in
     // cases where the `Val`s used for substitution should
     // lower to something other than their original form.
-    auto lowedNewSubst = lowerGenericSubstitutions(context, newSubst);
-    DeclRef<Decl> newDeclRef = DeclRef<Decl>(declRef.decl, 
-        SubstitutionSet(lowedNewSubst, declRef.substitutions.thisTypeSubstitution, 
-            declRef.substitutions.globalGenParamSubstitutions));
+    SubstitutionSet oldSubst = declRef.substitutions;
+    oldSubst.genericSubstitutions = newSubst;
+    auto lowedNewSubst = lowerSubstitutions(context, oldSubst);
+    DeclRef<Decl> newDeclRef = DeclRef<Decl>(declRef.decl, lowedNewSubst);
 
     RefPtr<Type> type;
     if (auto declType = val->getType())
@@ -4014,9 +4047,9 @@ static void lowerEntryPointToIR(
         return;
     }
     // we need to lower all global type arguments as well
+    auto loweredEntryPointFunc = ensureDecl(context, entryPointFuncDecl);
     for (auto arg : entryPointRequest->genericParameterTypes)
         lowerType(context, arg);
-    auto loweredEntryPointFunc = ensureDecl(context, entryPointFuncDecl);
 }
 
 #if 0
-- 
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