[NFC] Check that SILGen doesn’t use ABI-only decls

Adds assertions in various places where properties that can vary between ABI-only decls and their counterparts—particularly function and parameter attributes—are handled in SILGen, ensuring that we don’t accidentally end up processing ABI-only decls there.

Author: beccadax

lib/SIL/IR/SILDeclRef.cpp

@@ -451,6 +451,7 @@ static LinkageLimit getLinkageLimit(SILDeclRef constant) {
   using Kind = SILDeclRef::Kind;
 
   auto *d = constant.getDecl();
+  ASSERT(ABIRoleInfo(d).providesAPI() && "getLinkageLimit() for ABI decl?");
 
   // Back deployment thunks and fallbacks are emitted into the client.
   if (constant.backDeploymentKind != SILDeclRef::BackDeploymentKind::None)
@@ -1267,6 +1268,9 @@ std::string SILDeclRef::mangle(ManglingKind MKind) const {
     if (auto *ACE = getAbstractClosureExpr())
       return mangler.mangleClosureEntity(ACE, SKind);
 
+    ASSERT(ABIRoleInfo(getDecl()).providesAPI()
+              && "SILDeclRef mangling ABI decl directly?");
+
     // As a special case, functions can have manually mangled names.
     // Use the SILGen name only for the original non-thunked, non-curried entry
     // point.

lib/SIL/IR/SILFunctionBuilder.cpp

@@ -377,6 +377,9 @@ SILFunction *SILFunctionBuilder::getOrCreateFunction(
     if (auto *accessor = dyn_cast<AccessorDecl>(decl)) {
       auto *storage = accessor->getStorage();
       // Add attributes for e.g. computed properties.
+      ASSERT(ABIRoleInfo(storage).providesAPI()
+                && "addFunctionAttributes() on ABI-only accessor?");
+
       addFunctionAttributes(F, storage->getAttrs(), mod,
                             getOrCreateDeclaration);
 
@@ -395,6 +398,8 @@ SILFunction *SILFunctionBuilder::getOrCreateFunction(
         F->setInlineStrategy(NoInline);
       }
     }
+    ASSERT(ABIRoleInfo(decl).providesAPI()
+              && "addFunctionAttributes() on ABI-only decl?");
     addFunctionAttributes(F, decl->getAttrs(), mod, getOrCreateDeclaration,
                           constant);
   }

lib/SIL/IR/SILSymbolVisitor.cpp

@@ -491,6 +491,9 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
 
     addFunction(SILDeclRef(AFD));
 
+    ASSERT(ABIRoleInfo(AFD).providesAPI()
+              && "SILSymbolVisitorImpl visiting ABI-only decl?");
+
     if (auto dynKind = getDynamicKind(AFD)) {
       // Add the global function pointer for a dynamically replaceable function.
       Visitor.addDynamicFunction(AFD, *dynKind);

lib/SILGen/SILGen.cpp

@@ -1439,6 +1439,9 @@ void SILGenModule::emitAbstractFuncDecl(AbstractFunctionDecl *AFD) {
   // Emit default arguments and property wrapper initializers.
   emitArgumentGenerators(AFD, AFD->getParameters());
 
+  ASSERT(ABIRoleInfo(AFD).providesAPI()
+            && "emitAbstractFuncDecl() on ABI-only decl?");
+
   // If the declaration is exported as a C function, emit its native-to-foreign
   // thunk too, if it wasn't already forced.
   if (AFD->getAttrs().hasAttribute<CDeclAttr>()) {