Support generic interface methods (shader-slang#251)

* improve diagnostic messages and prevent fatal errors from crashing the compiler.

* fix top level exception catching.

* spelling fix

* change wording of invalidSwizzleExpr diagnostic

* add speculative GenericsApp expr parsing

* add new test case of cascading generics call.

* Fixing bugs in compiling cascaded generic function calls.

Add implementation of DeclaredSubTypeWitness::SubstituteImpl()

This is not needed by the type checker, but needed by IR specialization. When input source contains cascading generic function call, the arguments to `specialize` instruction is currently represented as a substitution. The arg values of this subsittution can be a `DeclaredSubTypeWitness` when a generic function uses one of its generic parameter to specialize another generic function. When the top level generics function is being specialized, this substitution argument, which is a `DeclaredSubTypeWitness`, needs to be substituted with the witness that used to specialize the top level function in the specialized specialize instruction as well.

* add a test case for cascading generic function call.

* parser bug fix

* fixes shader-slang#255

* add test case for issue shader-slang#255

* Generate missing `specialize` instruction when calling a generic method from an interface constraint.

When calling a generic method via an interface, we should be generating the following ir:
...
f = lookup_interface_method(...)
f_s = specailize(f, declRef)
...

This commit fixes this  `emitFuncRef` function to emit the needed `specialize` instruction.

* fixes shader-slang#260

This fix follows the second apporach in the disucssion. It generated mangled name for specialized functions by appending new substitution type names to the original mangled name.

* Disabling removing and re-inserting specailized functions in getSpecalizeFunc()

I am not sure why it is needed, it seems HLSL and GLSL backends are generating forward declarations anyways, so the order of functions in IRModule shouldn't matter.

* cleanup and complete test cases.

* fix warnings

Author: csyonghe

source/core/exception.h

@@ -121,6 +121,17 @@ namespace Slang
 		{
 		}
 	};
+
+    class AbortCompilationException : public Exception
+    {
+    public:
+        AbortCompilationException()
+        {}
+        AbortCompilationException(const String & message)
+            : Exception(message)
+        {
+        }
+    };
 }
 
 #endif

source/slang/check.cpp

@@ -1588,6 +1588,44 @@ namespace Slang
             return true;
         }
 
+        bool doesGenericSignatureMatchRequirement(
+            GenericDecl * genDecl,
+            DeclRef<GenericDecl> requirementGenDecl)
+        {
+            // TODO: genDecl should be a DeclRef to capture the environment generic variables needed to get 
+            // a concrete type for a generic constraint super type (e.g. when this member belongs to a generic type)
+
+            if (genDecl->Members.Count() != requirementGenDecl.getDecl()->Members.Count())
+                return false;
+            for (UInt i = 0; i < genDecl->Members.Count(); i++)
+            {
+                auto genMbr = genDecl->Members[i];
+                auto requiredGenMbr = genDecl->Members[i];
+                if (auto genTypeMbr = genMbr.As<GenericTypeParamDecl>())
+                {
+                    if (auto requiredGenTypeMbr = requiredGenMbr.As<GenericTypeParamDecl>())
+                    {
+                    }
+                    else
+                        return false;
+                }
+                else if (auto genTypeConstraintMbr = genMbr.As<GenericTypeConstraintDecl>())
+                {
+                    if (auto requiredTypeConstraintMbr = requiredGenMbr.As<GenericTypeConstraintDecl>())
+                    {
+                        if (!genTypeConstraintMbr->sup->Equals(requiredTypeConstraintMbr->sup))
+                        {
+                            return false;
+                        }
+                    }
+                    else
+                        return false;
+                }
+            }
+            return doesMemberSatisfyRequirement(genDecl->inner.Ptr(),
+                DeclRef<Decl>(requirementGenDecl.getDecl()->inner.Ptr(), requirementGenDecl.substitutions));
+        }
+
         // Does the given `memberDecl` work as an implementation
         // to satisfy the requirement `requiredMemberDeclRef`
         // from an interface?
@@ -1634,6 +1672,13 @@ namespace Slang
                         requiredInitDecl);
                 }
             }
+            else if (auto genDecl = dynamic_cast<GenericDecl*>(memberDecl))
+            {
+                if (auto requiredGenDeclRef = requiredMemberDeclRef.As<GenericDecl>())
+                {
+                    return doesGenericSignatureMatchRequirement(genDecl, requiredGenDeclRef);
+                }
+            }
             else if (auto subStructTypeDecl = dynamic_cast<AggTypeDecl*>(memberDecl))
             {
                 // this is a sub type (e.g. nested struct declaration) in an aggregate type
@@ -4462,9 +4507,13 @@ namespace Slang
 
             DeclRef<Decl> innerDeclRef(GetInner(baseGenericRef), subst);
 
+            RefPtr<Expr> base;
+            if (auto mbrExpr = baseExpr.As<MemberExpr>())
+                base = mbrExpr->BaseExpression;
+
             return ConstructDeclRefExpr(
                 innerDeclRef,
-                nullptr,
+                base,
                 originalExpr->loc);
         }
 
@@ -5738,7 +5787,6 @@ namespace Slang
             // declarations with the same name, so this becomes a specialized case of
             // overload resolution.
 
-
             // Start by checking the base expression and arguments.
             auto& baseExpr = genericAppExpr->FunctionExpr;
             baseExpr = CheckTerm(baseExpr);
@@ -6095,9 +6143,9 @@ namespace Slang
                 case 'w': case 'a': elementIndex = 3; break;
                 default:
                     // An invalid character in the swizzle is an error
-                    if (!isRewriteMode())
+                    if (!isRewriteMode() && !anyError)
                     {
-                        getSink()->diagnose(swizExpr, Diagnostics::unimplemented, "invalid component name for swizzle");
+                        getSink()->diagnose(swizExpr, Diagnostics::invalidSwizzleExpr, swizzleText, baseElementType->ToString());
                     }
                     anyError = true;
                     continue;
@@ -6109,9 +6157,9 @@ namespace Slang
                 // Make sure the index is in range for the source type
                 if (elementIndex >= limitElement)
                 {
-                    if (!isRewriteMode())
+                    if (!isRewriteMode() && !anyError)
                     {
-                        getSink()->diagnose(swizExpr, Diagnostics::unimplemented, "swizzle component out of range for type");
+                        getSink()->diagnose(swizExpr, Diagnostics::invalidSwizzleExpr, swizzleText, baseElementType->ToString());
                     }
                     anyError = true;
                     continue;

source/slang/diagnostic-defs.h

@@ -191,6 +191,7 @@ DIAGNOSTIC(30035, Error, componentOverloadTypeMismatch, "'$0': type of overloade
 DIAGNOSTIC(30041, Error, bitOperationNonIntegral, "bit operation: operand must be integral type.")
 DIAGNOSTIC(30047, Error, argumentExpectedLValue, "argument passed to parameter '$0' must be l-value.")
 DIAGNOSTIC(30051, Error, invalidValueForArgument, "invalid value for argument '$0'")
+DIAGNOSTIC(30052, Error, invalidSwizzleExpr, "invalid swizzle pattern '$0' on type '$1'")
 DIAGNOSTIC(33070, Error, expectedFunction, "expression preceding parenthesis of apparent call must have function type.")
 
 // 303xx: interfaces and associated types

source/slang/diagnostics.cpp

@@ -209,7 +209,7 @@ void DiagnosticSink::diagnoseImpl(SourceLoc const& pos, DiagnosticInfo const& in
     if (diagnostic.severity >= Severity::Fatal)
     {
         // TODO: figure out a better policy for aborting compilation
-        throw InvalidOperationException();
+        throw AbortCompilationException();
     }
 }
 

source/slang/emit.cpp

@@ -4754,7 +4754,7 @@ emitDeclImpl(decl, nullptr);
         void readSimpleIntVal()
         {
             int c = peek();
-            if(isDigit(c))
+            if(isDigit((char)c))
             {
                 get();
             }

source/slang/ir-legalize-types.cpp

@@ -469,12 +469,12 @@ static LegalVal legalizeFieldAddress(
                 }
             }
             SLANG_UNEXPECTED("didn't find tuple element");
-            return LegalVal();
+            UNREACHABLE_RETURN(LegalVal());
         }
 
     default:
         SLANG_UNEXPECTED("unhandled");
-        return LegalVal();
+        UNREACHABLE_RETURN(LegalVal());
     }
 }
 

source/slang/ir.cpp

@@ -55,15 +55,15 @@ namespace Slang
         }
     }
 
-    void IRUse::set(IRValue* usedValue)
+    void IRUse::set(IRValue* usedVal)
     {
         // clear out the old value
-        if (usedValue)
+        if (usedVal)
         {
             *prevLink = nextUse;
         }
 
-        init(user, usedValue);
+        init(user, usedVal);
     }
 
     void IRUse::clear()
@@ -3750,8 +3750,6 @@ namespace Slang
     {
         if( auto subtypeWitness = dynamic_cast<SubtypeWitness*>(val) )
         {
-            // We need to look up the IR value that represents the
-            // given subtype witness.
             String mangledName = getMangledNameForConformanceWitness(
                 subtypeWitness->sub,
                 subtypeWitness->sup);
@@ -3948,8 +3946,11 @@ namespace Slang
         // has already been made. To do that we will need to
         // compute the mangled name of the specialized function,
         // so that we can look for existing declarations.
-
-        String specMangledName = getMangledName(specDeclRef);
+        String specMangledName;
+        if (genericFunc->genericDecl == specDeclRef.decl)
+            specMangledName = getMangledName(specDeclRef);
+        else
+            specMangledName = mangleSpecializedFuncName(genericFunc->mangledName, specDeclRef.substitutions);
 
         // TODO: This is a terrible linear search, and we should
         // avoid it by building a dictionary ahead of time,
@@ -3992,8 +3993,8 @@ namespace Slang
         //
         // TODO: This shouldn't be needed, if we introduce a sorting
         // step before we emit code.
-        specFunc->removeFromParent();
-        specFunc->insertAfter(genericFunc);
+        //specFunc->removeFromParent();
+        //specFunc->insertAfter(genericFunc);
 
         // At this point we've created a new non-generic function,
         // which means we should add it to our work list for
@@ -4026,8 +4027,20 @@ namespace Slang
             auto keyDeclRef = ((IRDeclRef*) requirementKey)->declRef;
 
             // If the keys don't match, continue with the next entry.
-            if(!keyDeclRef.Equals(requirementDeclRef))
-                continue;
+            if (!keyDeclRef.Equals(requirementDeclRef))
+            {
+                // requirementDeclRef may be pointing to the inner decl of a generic decl
+                // in this case we compare keyDeclRef against the parent decl of requiredDeclRef
+                if (auto genRequiredDeclRef = requirementDeclRef.GetParent().As<GenericDecl>())
+                {
+                    if (!keyDeclRef.Equals(genRequiredDeclRef))
+                    {
+                        continue;
+                    }
+                }
+                else
+                    continue;
+            }
 
             // If the keys matched, then we use the value from
             // this entry.
@@ -4178,7 +4191,6 @@ namespace Slang
                             // Use the witness table to look up the value that
                             // satisfies the requirement.
                             auto satisfyingVal = findWitnessVal(witnessTable, requirementDeclRef);
-
                             // We expect to always find something, but lets just
                             // be careful here.
                             if(!satisfyingVal)

source/slang/lower-to-ir.cpp

@@ -314,6 +314,13 @@ LoweredValInfo emitDeclRef(
     IRGenContext*   context,
     DeclRef<Decl>   declRef);
 
+// Emit necessary `specialize` instruction needed by a declRef.
+// This is currently used by emitDeclRef() and emitFuncRef()
+LoweredValInfo maybeEmitSpecializeInst(IRGenContext*   context, 
+    LoweredValInfo loweredDecl,  // the lowered value of the inner decl
+    DeclRef<Decl>   declRef      // the full decl ref containing substitutions
+);
+
 
 IRValue* getSimpleVal(IRGenContext* context, LoweredValInfo lowered);
 
@@ -488,10 +495,11 @@ LoweredValInfo emitFuncRef(
 
                 RefPtr<Type> type = funcExpr->type;
 
-                return LoweredValInfo::simple(context->irBuilder->emitLookupInterfaceMethodInst(
+                auto loweredVal = LoweredValInfo::simple(context->irBuilder->emitLookupInterfaceMethodInst(
                     type,
                     baseMemberDeclRef,
                     funcDeclRef));
+                return maybeEmitSpecializeInst(context, loweredVal, funcDeclRef);
             }
         }
     }
@@ -2893,6 +2901,13 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         return LoweredValInfo::simple(irFunc);
     }
 
+    LoweredValInfo visitGenericDecl(GenericDecl * genDecl)
+    {
+        if (auto innerFuncDecl = genDecl->inner->As<FuncDecl>())
+            return lowerFuncDecl(innerFuncDecl);
+        SLANG_RELEASE_ASSERT(false);
+        UNREACHABLE_RETURN(LoweredValInfo());
+    }
 
     LoweredValInfo visitFunctionDeclBase(FunctionDeclBase* decl)
     {
@@ -2997,6 +3012,11 @@ RefPtr<Val> lowerSubstitutionArg(
     }
     else if (auto declaredSubtypeWitness = dynamic_cast<DeclaredSubtypeWitness*>(val))
     {
+        // We do not have a concrete witness table yet for a GenericTypeConstraintDecl witness
+
+        if (declaredSubtypeWitness->declRef.As<GenericTypeConstraintDecl>())
+            return val;
+
         // We need to look up the IR-level representation of the witness
         // (which is a witness table).
 
@@ -3073,9 +3093,16 @@ LoweredValInfo emitDeclRef(
     // unspecialized declaration.
     LoweredValInfo loweredDecl = ensureDecl(context, declRef.getDecl());
 
+    return maybeEmitSpecializeInst(context, loweredDecl, declRef);
+}
+
+LoweredValInfo maybeEmitSpecializeInst(IRGenContext*   context,
+    LoweredValInfo loweredDecl,
+    DeclRef<Decl>   declRef)
+{
     // If this declaration reference doesn't involve any specializations,
     // then we are done at this point.
-    if(!hasGenericSubstitutions(declRef.substitutions))
+    if (!hasGenericSubstitutions(declRef.substitutions))
         return loweredDecl;
 
     auto val = getSimpleVal(context, loweredDecl);
@@ -3089,7 +3116,7 @@ LoweredValInfo emitDeclRef(
 
 
     RefPtr<Type> type;
-    if(auto declType = val->getType())
+    if (auto declType = val->getType())
     {
         type = declType->Substitute(declRef.substitutions).As<Type>();
     }
@@ -3102,6 +3129,7 @@ LoweredValInfo emitDeclRef(
         declRef));
 }
 
+
 static void lowerEntryPointToIR(
     IRGenContext*       context,
     EntryPointRequest*  entryPointRequest)

source/slang/mangle.cpp

@@ -350,6 +350,24 @@ namespace Slang
             DeclRef<Decl>(declRef.decl, declRef.substitutions));
     }
 
+    String mangleSpecializedFuncName(String baseName, RefPtr<Substitutions> subst)
+    {
+        ManglingContext context;
+        emitRaw(&context, baseName.Buffer());
+        emitRaw(&context, "_G");
+        while (subst)
+        {
+            if (auto genSubst = subst.As<GenericSubstitution>())
+            {
+                for (auto a : genSubst->args)
+                    emitVal(&context, a);
+                break;
+            }
+            subst = subst->outer;
+        }
+        return context.sb.ProduceString();
+    }
+
     String getMangledName(Decl* decl)
     {
         return getMangledName(makeDeclRef(decl));

source/slang/mangle.h

@@ -11,7 +11,7 @@ namespace Slang
     String getMangledName(Decl* decl);
     String getMangledName(DeclRef<Decl> const & declRef);
     String getMangledName(DeclRefBase const & declRef);
-
+    String mangleSpecializedFuncName(String baseName, RefPtr<Substitutions> subst);
     String getMangledNameForConformanceWitness(
         Type* sub,
         Type* sup);