Replace DtoIsTemplateInstance() by Dsymbol::isInstantiated()

The semantics were almost identical, except for DtoIsTemplateInstance()
checking the specified Dsymbol and its parents, while isInstantiated()
starts from its parent and ignores the symbol itself.

After a quick glance, we seem to have fed it with {Aggregate,Func,Var}
Declarations only, so should be fine with the default front-end variant.

gen/functions.cpp

@@ -578,18 +578,21 @@ void DtoDeclareFunction(FuncDeclaration *fdecl, const bool willDefine) {
   bool defineAtEnd = false;
   bool defineAsAvailableExternally = false;
   if (willDefine) {
+    // will be defined anyway after declaration
   } else if (defineOnDeclare(fdecl)) {
+    Logger::println("Function is inside a linkonce_odr template, will be "
+                    "defined after declaration.");
     if (fdecl->semanticRun < PASSsemantic3done) {
+      // this can e.g. happen for special __xtoHash member functions
+      Logger::println("Function hasn't had sema3 run yet, running it now.");
       const bool semaSuccess = fdecl->functionSemantic3();
       assert(semaSuccess);
       Module::runDeferredSemantic3();
     }
-    IF_LOG Logger::println("Function is inside a linkonce_odr template, will "
-                           "be defined after declaration.");
     defineAtEnd = true;
   } else if (defineAsExternallyAvailable(*fdecl)) {
-    IF_LOG Logger::println("Function is an externally_available inline "
-                           "candidate, will be defined after declaration.");
+    Logger::println("Function is an externally_available inline candidate, "
+                    "will be defined after declaration.");
     defineAtEnd = true;
     defineAsAvailableExternally = true;
   }

gen/llvmhelpers.cpp

@@ -795,18 +795,8 @@ DValue *DtoPaintType(Loc &loc, DValue *val, Type *to) {
  * TEMPLATE HELPERS
  ******************************************************************************/
 
-TemplateInstance *DtoIsTemplateInstance(Dsymbol *s) {
-  for (; s; s = s->parent) {
-    if (auto ti = s->isTemplateInstance()) {
-      if (!ti->isTemplateMixin())
-        return ti;
-    }
-  }
-  return nullptr;
-}
-
 bool defineOnDeclare(Dsymbol* s) {
-  return global.params.linkonceTemplates && DtoIsTemplateInstance(s);
+  return global.params.linkonceTemplates && s->isInstantiated();
 }
 
 /******************************************************************************

gen/llvmhelpers.h

@@ -101,8 +101,6 @@ DValue *DtoCast(Loc &loc, DValue *val, Type *to);
 // otherwise returns a new DValue
 DValue *DtoPaintType(Loc &loc, DValue *val, Type *to);
 
-// is template instance check, returns module where instantiated
-TemplateInstance *DtoIsTemplateInstance(Dsymbol *s);
 /// Returns true if the specified symbol is to be defined on declaration, for
 /// -linkonce-templates.
 bool defineOnDeclare(Dsymbol *s);

gen/naked.cpp

@@ -170,7 +170,7 @@ void DtoDefineNakedFunction(FuncDeclaration *fd) {
     asmstr << "\t.section\t__TEXT,__text,regular,pure_instructions"
            << std::endl;
     asmstr << "\t.globl\t" << mangle << std::endl;
-    if (DtoIsTemplateInstance(fd)) {
+    if (fd->isInstantiated()) {
       asmstr << "\t.weak_definition\t" << mangle << std::endl;
     }
     asmstr << "\t.p2align\t4, 0x90" << std::endl;
@@ -198,7 +198,7 @@ void DtoDefineNakedFunction(FuncDeclaration *fd) {
     asmstr << "\t.type\t32;" << std::endl;
     asmstr << "\t.endef" << std::endl;
 
-    if (DtoIsTemplateInstance(fd)) {
+    if (fd->isInstantiated()) {
       asmstr << "\t.section\t.text,\"xr\",discard," << mangle << std::endl;
     } else {
       asmstr << "\t.text" << std::endl;
@@ -207,7 +207,7 @@ void DtoDefineNakedFunction(FuncDeclaration *fd) {
     asmstr << "\t.p2align\t4, 0x90" << std::endl;
     asmstr << mangle << ":" << std::endl;
   } else {
-    if (DtoIsTemplateInstance(fd)) {
+    if (fd->isInstantiated()) {
       asmstr << "\t.section\t.text." << mangle << ",\"axG\",@progbits,"
              << mangle << ",comdat" << std::endl;
       asmstr << "\t.weak\t" << mangle << std::endl;

gen/tollvm.cpp

@@ -221,7 +221,7 @@ LinkageWithCOMDAT DtoLinkage(Dsymbol *sym) {
   }
   // Function (incl. delegate) literals are emitted into each referencing
   // compilation unit; use template linkage to prevent conflicts.
-  else if (sym->isFuncLiteralDeclaration() || DtoIsTemplateInstance(sym)) {
+  else if (sym->isFuncLiteralDeclaration() || sym->isInstantiated()) {
     linkage = templateLinkage;
   } else {
     linkage = LLGlobalValue::ExternalLinkage;

ir/iraggr.cpp

@@ -83,8 +83,8 @@ LLConstant *IrAggr::getInitSymbol(bool define) {
 
     init = initGlobal;
 
-    if (!define && defineOnDeclare(aggrdecl))
-      define = true;
+    if (!define)
+      define = defineOnDeclare(aggrdecl);
   }
 
   if (define) {

ir/irclass.cpp

@@ -72,8 +72,8 @@ LLGlobalVariable *IrClass::getVtblSymbol(bool define) {
     vtbl = declareGlobal(aggrdecl->loc, gIR->module, vtblTy, irMangle,
                          /*isConstant=*/true);
 
-    if (!define && defineOnDeclare(aggrdecl))
-      define = true;
+    if (!define)
+      define = defineOnDeclare(aggrdecl);
   }
 
   if (define) {
@@ -131,8 +131,8 @@ LLGlobalVariable *IrClass::getClassInfoSymbol(bool define) {
           gIR->context(), llvm::makeArrayRef(mdVals, CD_NumFields)));
     }
 
-    if (!define && defineOnDeclare(aggrdecl))
-      define = true;
+    if (!define)
+      define = defineOnDeclare(aggrdecl);
   }
 
   if (define) {
@@ -473,8 +473,8 @@ llvm::GlobalVariable *IrClass::getInterfaceVtblSymbol(BaseClass *b,
     // insert into the vtbl map
     interfaceVtblMap.insert({{b->sym, interfaces_index}, gvar});
 
-    if (!define && defineOnDeclare(aggrdecl))
-      define = true;
+    if (!define)
+      define = defineOnDeclare(aggrdecl);
   }
 
   if (define && !gvar->hasInitializer()) {

ir/irstruct.cpp

@@ -54,8 +54,8 @@ LLGlobalVariable* IrStruct::getTypeInfoSymbol(bool define) {
 
     emitTypeInfoMetadata(typeInfo, aggrdecl->type);
 
-    if (!define && defineOnDeclare(aggrdecl))
-      define = true;
+    if (!define)
+      define = defineOnDeclare(aggrdecl);
   }
 
   if (define) {

ir/irvar.cpp

@@ -28,8 +28,8 @@ LLValue *IrGlobal::getValue(bool define) {
   if (!value) {
     declare();
 
-    if (!define && defineOnDeclare(V))
-      define = true;
+    if (!define)
+      define = defineOnDeclare(V);
   }
 
   if (define && !(V->storage_class & STCextern)) {