[clang] [Parser][ObjC] Add -Wobjc-prefix-length warning option. (PR #97597)
Alastair Houghton via cfe-commits
cfe-commits at lists.llvm.org
Wed Jul 3 09:03:35 PDT 2024
https://github.com/al45tair created https://github.com/llvm/llvm-project/pull/97597
This lets clang generate warnings automatically if it sees Objective-C names that don't have the correct prefix length.
rdar://131055157
>From 02f7c5ef71b382866e02037ce82c85fa6fcbb394 Mon Sep 17 00:00:00 2001
From: Alastair Houghton <ahoughton at apple.com>
Date: Wed, 3 Jul 2024 17:00:51 +0100
Subject: [PATCH] [Parser][ObjC] Add -Wobjc-prefix-length warning option.
This lets clang generate warnings automatically if it sees Objective-C
names that don't have the correct prefix length.
rdar://131055157
---
clang/include/clang/Basic/DiagnosticGroups.td | 1 +
.../clang/Basic/DiagnosticParseKinds.td | 7 ++
clang/include/clang/Basic/LangOptions.def | 2 +
clang/include/clang/Driver/Options.td | 7 ++
clang/include/clang/Parse/Parser.h | 1 +
clang/lib/Driver/ToolChains/Clang.cpp | 1 +
clang/lib/Parse/ParseObjc.cpp | 65 +++++++++++++++++++
clang/test/Parser/objc-prefixes.m | 62 ++++++++++++++++++
8 files changed, 146 insertions(+)
create mode 100644 clang/test/Parser/objc-prefixes.m
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 9431eea1f6be2..0d944434cda38 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -598,6 +598,7 @@ def ObjCPointerIntrospect : DiagGroup<"deprecated-objc-pointer-introspection", [
def ObjCMultipleMethodNames : DiagGroup<"objc-multiple-method-names">;
def ObjCFlexibleArray : DiagGroup<"objc-flexible-array">;
def ObjCBoxing : DiagGroup<"objc-boxing">;
+def ObjCPrefixLength : DiagGroup<"objc-prefix-length">;
def CompletionHandler : DiagGroup<"completion-handler">;
def CalledOnceParameter : DiagGroup<"called-once-parameter", [CompletionHandler]>;
def OpenCLUnsupportedRGBA: DiagGroup<"opencl-unsupported-rgba">;
diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 12aab09f28556..7e26bd13f9c7b 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -563,6 +563,13 @@ def err_declaration_does_not_declare_param : Error<
"declaration does not declare a parameter">;
def err_no_matching_param : Error<"parameter named %0 is missing">;
+def warn_objc_unprefixed_class_name : Warning<
+ "un-prefixed Objective-C class name">,
+ InGroup<ObjCPrefixLength>;
+def warn_objc_unprefixed_protocol_name : Warning<
+ "un-prefixed Objective-C protocol name">,
+ InGroup<ObjCPrefixLength>;
+
/// Objective-C++ parser diagnostics
def err_expected_token_instead_of_objcxx_keyword : Error<
"expected %0; %1 is a keyword in Objective-C++">;
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index 491759e2fcdbb..9df19b01f0b22 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -351,6 +351,8 @@ LANGOPT(ObjCAutoRefCount , 1, 0, "Objective-C automated reference counting")
LANGOPT(ObjCWeakRuntime , 1, 0, "__weak support in the ARC runtime")
LANGOPT(ObjCWeak , 1, 0, "Objective-C __weak in ARC and MRC files")
LANGOPT(ObjCSubscriptingLegacyRuntime , 1, 0, "Subscripting support in legacy ObjectiveC runtime")
+BENIGN_LANGOPT(ObjCPrefixLength, 32, 0,
+ "if non-zero, warn about Objective-C classes or protocols with names that do not have a prefix of the specified length.")
BENIGN_LANGOPT(CompatibilityQualifiedIdBlockParamTypeChecking, 1, 0,
"compatibility mode for type checking block parameters "
"involving qualified id types")
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 1ede75d3782cd..829efafd03a2c 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3418,6 +3418,13 @@ defm objc_exceptions : BoolFOption<"objc-exceptions",
PosFlag<SetTrue, [], [ClangOption, CC1Option],
"Enable Objective-C exceptions">,
NegFlag<SetFalse>>;
+def Wobjc_prefix_length_EQ:
+ Joined<["-"], "Wobjc-prefix-length=">,
+ Visibility<[ClangOption, CC1Option]>,
+ MetaVarName<"<N>">,
+ HelpText<"Warn if Objective-C class or protocol names do not start with a prefix of the specified length">,
+ MarshallingInfoInt<LangOpts<"ObjCPrefixLength">>;
+
defm application_extension : BoolFOption<"application-extension",
LangOpts<"AppExt">, DefaultFalse,
PosFlag<SetTrue, [], [ClangOption, CC1Option],
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 6880fa4bb0b03..0e2fdc44321b5 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -1704,6 +1704,7 @@ class Parser : public CodeCompletionHandler {
// Objective-C External Declarations
void MaybeSkipAttributes(tok::ObjCKeywordKind Kind);
+ bool isValidObjCPublicName(StringRef name);
DeclGroupPtrTy ParseObjCAtDirectives(ParsedAttributes &DeclAttrs,
ParsedAttributes &DeclSpecAttrs);
DeclGroupPtrTy ParseObjCAtClassDeclaration(SourceLocation atLoc);
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 27c451c565f2b..c66914b0686c8 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -6291,6 +6291,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
}
Args.AddAllArgs(CmdArgs, options::OPT_Wsystem_headers_in_module_EQ);
+ Args.AddLastArg(CmdArgs, options::OPT_Wobjc_prefix_length_EQ);
if (Args.hasFlag(options::OPT_pedantic, options::OPT_no_pedantic, false))
CmdArgs.push_back("-pedantic");
diff --git a/clang/lib/Parse/ParseObjc.cpp b/clang/lib/Parse/ParseObjc.cpp
index 6a2088a73c55b..006328140d0eb 100644
--- a/clang/lib/Parse/ParseObjc.cpp
+++ b/clang/lib/Parse/ParseObjc.cpp
@@ -204,6 +204,57 @@ void Parser::CheckNestedObjCContexts(SourceLocation AtLoc)
Diag(Decl->getBeginLoc(), diag::note_objc_container_start) << (int)ock;
}
+/// An Objective-C public name (a class name or protocol name) is
+/// expected to have a prefix as all names are in a single global
+/// namespace.
+///
+/// If the -Wobjc-prefix-length is set to N, the name must start
+/// with N+1 capital letters, which must be followed by a character
+/// that is not a capital letter.
+///
+/// For instance, for N set to 2, the following are valid:
+///
+/// NSString
+/// NSArray
+///
+/// but these are not:
+///
+/// MyString
+/// NSKString
+/// NSnotAString
+///
+/// We make a special exception for NSCF things when the prefix is set
+/// to length 2, because that's an unusual special case in the implementation
+/// of the Cocoa frameworks.
+///
+/// Names that start with underscores are exempt from this check, but
+/// are reserved for the system and should not be used by user code.
+bool Parser::isValidObjCPublicName(StringRef name) {
+ size_t nameLen = name.size();
+ size_t requiredUpperCase = getLangOpts().ObjCPrefixLength + 1;
+
+ if (name.starts_with('_'))
+ return true;
+
+ // Special case for NSCF when prefix length is 2
+ if (requiredUpperCase == 3 && nameLen > 4 && name.starts_with("NSCF") &&
+ isUppercase(name[4]) && (nameLen == 5 || !isUppercase(name[5])))
+ return true;
+
+ if (nameLen < requiredUpperCase)
+ return false;
+
+ for (size_t n = 0; n < requiredUpperCase; ++n) {
+ if (!isUppercase(name[n]))
+ return false;
+ }
+
+ if (nameLen > requiredUpperCase && isUppercase(name[requiredUpperCase]))
+ return false;
+
+ return true;
+}
+
///
/// objc-interface:
/// objc-class-interface-attributes[opt] objc-class-interface
@@ -319,6 +370,14 @@ Decl *Parser::ParseObjCAtInterfaceDeclaration(SourceLocation AtLoc,
return CategoryType;
}
+
+ // Not a category - we are declaring a class
+ if (getLangOpts().ObjCPrefixLength &&
+ !PP.getSourceManager().isInSystemHeader(nameLoc) &&
+ !isValidObjCPublicName(nameId->getName())) {
+ Diag(nameLoc, diag::warn_objc_unprefixed_class_name);
+ }
+
// Parse a class interface.
IdentifierInfo *superClassId = nullptr;
SourceLocation superClassLoc;
@@ -2081,6 +2140,12 @@ Parser::ParseObjCAtProtocolDeclaration(SourceLocation AtLoc,
IdentifierInfo *protocolName = Tok.getIdentifierInfo();
SourceLocation nameLoc = ConsumeToken();
+ if (getLangOpts().ObjCPrefixLength &&
+ !PP.getSourceManager().isInSystemHeader(nameLoc) &&
+ !isValidObjCPublicName(protocolName->getName())) {
+ Diag(nameLoc, diag::warn_objc_unprefixed_protocol_name);
+ }
+
if (TryConsumeToken(tok::semi)) { // forward declaration of one protocol.
IdentifierLocPair ProtoInfo(protocolName, nameLoc);
return Actions.ObjC().ActOnForwardProtocolDeclaration(AtLoc, ProtoInfo,
diff --git a/clang/test/Parser/objc-prefixes.m b/clang/test/Parser/objc-prefixes.m
new file mode 100644
index 0000000000000..32c8448f93fbe
--- /dev/null
+++ b/clang/test/Parser/objc-prefixes.m
@@ -0,0 +1,62 @@
+// RUN: %clang_cc1 %s -Wobjc-prefix-length=2 -fsyntax-only -verify
+
+// Test prefix length rules for ObjC interfaces and protocols
+
+// -- Plain interfaces --------------------------------------------------------
+
+ at interface _Foo
+ at end
+
+ at interface Foo // expected-warning {{un-prefixed Objective-C class name}}
+ at end
+
+ at interface NSFoo
+ at end
+
+// Special case for prefix-length 2
+ at interface NSCFFoo
+ at end
+
+ at interface NSCFXFoo // expected-warning {{un-prefixed Objective-C class name}}
+ at end
+
+ at interface NSXFoo // expected-warning {{un-prefixed Objective-C class name}}
+ at end
+
+// -- Categories --------------------------------------------------------------
+
+// Categories don't trigger these warnings
+
+ at interface Foo (Bar)
+ at end
+
+ at interface NSFoo (Bar)
+ at end
+
+ at interface NSCFFoo (Bar)
+ at end
+
+ at interface NSXFoo (Bar)
+ at end
+
+// -- Protocols ---------------------------------------------------------------
+
+ at protocol _FooProtocol
+ at end
+
+ at protocol FooProtocol // expected-warning {{un-prefixed Objective-C protocol name}}
+ at end
+
+ at protocol NSFooProtocol
+ at end
+
+// Special case for prefix-length 2
+ at protocol NSCFFooProtocol
+ at end
+
+ at protocol NSCFXFooProtocol // expected-warning {{un-prefixed Objective-C protocol name}}
+ at end
+
+ at protocol NSXFooProtocol // expected-warning {{un-prefixed Objective-C protocol name}}
+ at end
+
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