Make inlinability non-ABI for @abi

Inlinability doesn’t affect the mangling except in function specializations, which are applied after the fact and should never mangle in information from an ABI-only decl. That means we can simply ban these from `@abi` instead of inferring them.

Also adds some assertions to help double-check that SIL never tries to directly mangle or retrieve inlinability info from an ABI-only decl.

Author: beccadax

Diff for: include/swift/AST/DeclAttr.def

@@ -163,7 +163,7 @@ SIMPLE_DECL_ATTR(unsafe_no_objc_tagged_pointer, UnsafeNoObjCTaggedPointer,
 
 DECL_ATTR(inline, Inline,
   OnVar | OnSubscript | OnAbstractFunction,
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   20)
 
 DECL_ATTR(_semantics, Semantics,
@@ -193,7 +193,7 @@ CONTEXTUAL_SIMPLE_DECL_ATTR(postfix, Postfix,
 
 SIMPLE_DECL_ATTR(_transparent, Transparent,
   OnFunc | OnAccessor | OnConstructor | OnVar | OnDestructor,
-  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  UserInaccessible | ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   26)
 
 SIMPLE_DECL_ATTR(requires_stored_property_inits, RequiresStoredPropertyInits,
@@ -216,7 +216,7 @@ SIMPLE_DECL_ATTR(_fixed_layout, FixedLayout,
 
 SIMPLE_DECL_ATTR(inlinable, Inlinable,
   OnVar | OnSubscript | OnAbstractFunction,
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   32)
 
 DECL_ATTR(_specialize, Specialize,
@@ -465,7 +465,7 @@ DECL_ATTR(_private, PrivateImport,
 
 SIMPLE_DECL_ATTR(_alwaysEmitIntoClient, AlwaysEmitIntoClient,
   OnVar | OnSubscript | OnAbstractFunction,
-  UserInaccessible | ABIBreakingToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | InferredInABIAttr,
+  UserInaccessible | ABIBreakingToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove | ForbiddenInABIAttr,
   83)
 
 SIMPLE_DECL_ATTR(_implementationOnly, ImplementationOnly,

Diff for: lib/SIL/IR/SILDeclRef.cpp

@@ -883,6 +883,9 @@ SerializedKind_t SILDeclRef::getSerializedKind() const {
 
   auto *d = getDecl();
 
+  ASSERT(ABIRoleInfo(d).providesAPI()
+            && "should not get serialization info from ABI-only decl");
+
   // Default and property wrapper argument generators are serialized if the
   // containing declaration is public.
   if (isDefaultArgGenerator() || (isPropertyWrapperBackingInitializer() &&
@@ -1021,6 +1024,9 @@ bool SILDeclRef::isNoinline() const {
     return false;
 
   auto *decl = getDecl();
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "should not get inline attr from ABI-only decl");
+
   if (auto *attr = decl->getAttrs().getAttribute<InlineAttr>())
     if (attr->getKind() == InlineKind::Never)
       return true;
@@ -1051,6 +1057,9 @@ bool SILDeclRef::isAlwaysInline() const {
     return false;
   }
 
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "should not get inline attr from ABI-only decl");
+
   if (auto attr = decl->getAttrs().getAttribute<InlineAttr>())
     if (attr->getKind() == InlineKind::Always)
       return true;
@@ -1070,6 +1079,10 @@ bool SILDeclRef::isBackDeployed() const {
     return false;
 
   auto *decl = getDecl();
+
+  ASSERT(ABIRoleInfo(decl).providesAPI()
+            && "should not get backDeployed from ABI-only decl");
+
   if (auto afd = dyn_cast<AbstractFunctionDecl>(decl))
     return afd->isBackDeployed(getASTContext());
 
@@ -1198,6 +1211,9 @@ static std::string mangleClangDecl(Decl *decl, bool isForeign) {
 }
 
 std::string SILDeclRef::mangle(ManglingKind MKind) const {
+  ASSERT(!hasDecl() || ABIRoleInfo(getDecl()).providesAPI()
+            && "SILDeclRef mangling ABI decl directly?");
+
   using namespace Mangle;
   ASTMangler mangler(getASTContext());
 
@@ -1268,9 +1284,6 @@ 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.

Diff for: test/attr/attr_abi.swift

@@ -1869,45 +1869,48 @@ func section2() {}
 @abi(func section3())
 @_section("fnord") func section3() {}
 
-// @inlinable -- automatically cloned into @abi
-@abi(@inlinable func inlinable1())
+// @inlinable -- banned in @abi
+// Although the inlining *does* occasionally get mangled, it's only done in the
+// SpecializationManglers, which shouldn't get their serialization from an ABI
+// attribute.
+@abi(@inlinable func inlinable1()) // expected-error {{unused 'inlinable' attribute in '@abi'}} {{6-16=}}
 @inlinable func inlinable1() {}
 
-@abi(@inlinable func inlinable2()) // expected-error {{extra 'inlinable' attribute in '@abi'}} {{6-16=}}
+@abi(@inlinable func inlinable2()) // expected-error {{unused 'inlinable' attribute in '@abi'}} {{6-16=}}
 func inlinable2() {}
 
-@abi(func inlinable3()) // expected-remark {{inferred '@inlinable' in '@abi' to match attribute on API}}
-@inlinable func inlinable3() {} // expected-note {{matches attribute here}}
+@abi(func inlinable3())
+@inlinable func inlinable3() {}
 
-// @inline -- automatically cloned into @abi
-@abi(@inline(never) func inline1())
+// @inlinable -- banned in @abi
+@abi(@inline(never) func inline1()) // expected-error {{unused 'inline(never)' attribute in '@abi'}} {{6-20=}}
 @inline(never) func inline1() {}
 
-@abi(@inline(never) func inline2()) // expected-error {{extra 'inline(never)' attribute in '@abi'}} {{6-20=}}
+@abi(@inline(never) func inline2()) // expected-error {{unused 'inline(never)' attribute in '@abi'}} {{6-20=}}
 func inline2() {}
 
-@abi(func inline3()) // expected-remark {{inferred '@inline(never)' in '@abi' to match attribute on API}}
-@inline(never) func inline3() {} // expected-note {{matches attribute here}}
+@abi(func inline3())
+@inline(never) func inline3() {}
 
-// @_transparent -- automatically cloned into @abi
-@abi(@_transparent func transparent1())
+// @_transparent -- banned in @abi
+@abi(@_transparent func transparent1()) // expected-error {{unused '_transparent' attribute in '@abi'}} {{6-19=}}
 @_transparent func transparent1() {}
 
-@abi(@_transparent func transparent2()) // expected-error {{extra '_transparent' attribute in '@abi'}} {{6-19=}}
+@abi(@_transparent func transparent2()) // expected-error {{unused '_transparent' attribute in '@abi'}} {{6-19=}}
 func transparent2() {}
 
-@abi(func transparent3()) // expected-remark {{inferred '@_transparent' in '@abi' to match attribute on API}}
-@_transparent func transparent3() {} // expected-note {{matches attribute here}}
+@abi(func transparent3())
+@_transparent func transparent3() {}
 
-// @_alwaysEmitIntoClient -- automatically cloned into @abi
-@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient1())
+// @_alwaysEmitIntoClient -- banned in @abi
+@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient1()) // expected-error {{unused '_alwaysEmitIntoClient' attribute in '@abi'}} {{6-28=}}
 @_alwaysEmitIntoClient func alwaysEmitIntoClient1() {}
 
-@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient2()) // expected-error {{extra '_alwaysEmitIntoClient' attribute in '@abi'}} {{6-28=}}
+@abi(@_alwaysEmitIntoClient func alwaysEmitIntoClient2()) // expected-error {{unused '_alwaysEmitIntoClient' attribute in '@abi'}} {{6-28=}}
 func alwaysEmitIntoClient2() {}
 
-@abi(func alwaysEmitIntoClient3()) // expected-remark {{inferred '@_alwaysEmitIntoClient' in '@abi' to match attribute on API}}
-@_alwaysEmitIntoClient func alwaysEmitIntoClient3() {} // expected-note {{matches attribute here}}
+@abi(func alwaysEmitIntoClient3())
+@_alwaysEmitIntoClient func alwaysEmitIntoClient3() {}
 
 // @_optimize(none) -- banned in @abi
 @abi(@_optimize(none) func optimize1()) // expected-error {{unused '_optimize(none)' attribute in '@abi'}} {{6-22=}}