Automatic Reference Counting.
Language-design credit goes to a lot of people, but I particularly want
to single out Blaine Garst and Patrick Beard for their contributions.
Compiler implementation credit goes to Argyrios, Doug, Fariborz, and myself,
in no particular order.
llvm-svn: 133103
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 147a8df..f1e1d47 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -221,6 +221,125 @@
ConstSuffix);
}
+/// \brief Add definitions required for a smooth interaction between
+/// Objective-C++ automatic reference counting and libc++.
+static void AddObjCXXARCLibcxxDefines(const LangOptions &LangOpts,
+ MacroBuilder &Builder) {
+ Builder.defineMacro("_LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF");
+
+ std::string Result;
+ {
+ // Provide overloads of the function std::__1::addressof() that accept
+ // references to lifetime-qualified objects. libc++'s (more general)
+ // std::__1::addressof() template fails to instantiate with such types,
+ // because it attempts to convert the object to a char& before
+ // dereferencing.
+ llvm::raw_string_ostream Out(Result);
+
+ Out << "#pragma clang diagnostic push\n"
+ << "#pragma clang diagnostic ignored \"-Wc++0x-extensions\"\n"
+ << "namespace std { inline namespace __1 {\n"
+ << "\n";
+
+ Out << "template <class _Tp>\n"
+ << "inline __attribute__ ((__visibility__(\"hidden\"), "
+ << "__always_inline__))\n"
+ << "__attribute__((objc_lifetime(strong))) _Tp*\n"
+ << "addressof(__attribute__((objc_lifetime(strong))) _Tp& __x) {\n"
+ << " return &__x;\n"
+ << "}\n"
+ << "\n";
+
+ if (!LangOpts.ObjCNoAutoRefCountRuntime) {
+ Out << "template <class _Tp>\n"
+ << "inline __attribute__ ((__visibility__(\"hidden\"),"
+ << "__always_inline__))\n"
+ << "__attribute__((objc_lifetime(weak))) _Tp*\n"
+ << "addressof(__attribute__((objc_lifetime(weak))) _Tp& __x) {\n"
+ << " return &__x;\n"
+ << "};\n"
+ << "\n";
+ }
+
+ Out << "template <class _Tp>\n"
+ << "inline __attribute__ ((__visibility__(\"hidden\"),"
+ << "__always_inline__))\n"
+ << "__attribute__((objc_lifetime(autoreleasing))) _Tp*\n"
+ << "addressof(__attribute__((objc_lifetime(autoreleasing))) _Tp& __x) "
+ << "{\n"
+ << " return &__x;\n"
+ << "}\n"
+ << "\n";
+
+ Out << "template <class _Tp>\n"
+ << "inline __attribute__ ((__visibility__(\"hidden\"), "
+ << "__always_inline__))\n"
+ << "__unsafe_unretained _Tp* addressof(__unsafe_unretained _Tp& __x)"
+ << " {\n"
+ << " return &__x;\n"
+ << "}\n";
+
+ Out << "\n"
+ << "} }\n"
+ << "#pragma clang diagnostic pop\n"
+ << "\n";
+ }
+ Builder.append(Result);
+}
+
+/// \brief Add definitions required for a smooth interaction between
+/// Objective-C++ automated reference counting and libstdc++ (4.2).
+static void AddObjCXXARCLibstdcxxDefines(const LangOptions &LangOpts,
+ MacroBuilder &Builder) {
+ Builder.defineMacro("_GLIBCXX_PREDEFINED_OBJC_ARC_IS_SCALAR");
+
+ std::string Result;
+ {
+ // Provide specializations for the __is_scalar type trait so that
+ // lifetime-qualified objects are not considered "scalar" types, which
+ // libstdc++ uses as an indicator of the presence of trivial copy, assign,
+ // default-construct, and destruct semantics (none of which hold for
+ // lifetime-qualified objects in ARC).
+ llvm::raw_string_ostream Out(Result);
+
+ Out << "namespace std {\n"
+ << "\n"
+ << "struct __true_type;\n"
+ << "struct __false_type;\n"
+ << "\n";
+
+ Out << "template<typename _Tp> struct __is_scalar;\n"
+ << "\n";
+
+ Out << "template<typename _Tp>\n"
+ << "struct __is_scalar<__attribute__((objc_lifetime(strong))) _Tp> {\n"
+ << " enum { __value = 0 };\n"
+ << " typedef __false_type __type;\n"
+ << "};\n"
+ << "\n";
+
+ if (!LangOpts.ObjCNoAutoRefCountRuntime) {
+ Out << "template<typename _Tp>\n"
+ << "struct __is_scalar<__attribute__((objc_lifetime(weak))) _Tp> {\n"
+ << " enum { __value = 0 };\n"
+ << " typedef __false_type __type;\n"
+ << "};\n"
+ << "\n";
+ }
+
+ Out << "template<typename _Tp>\n"
+ << "struct __is_scalar<__attribute__((objc_lifetime(autoreleasing)))"
+ << " _Tp> {\n"
+ << " enum { __value = 0 };\n"
+ << " typedef __false_type __type;\n"
+ << "};\n"
+ << "\n";
+
+ Out << "}\n";
+ }
+ Builder.append(Result);
+}
+
static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
const LangOptions &LangOpts,
const FrontendOptions &FEOpts,
@@ -560,6 +679,7 @@
const PreprocessorOptions &InitOpts,
const HeaderSearchOptions &HSOpts,
const FrontendOptions &FEOpts) {
+ const LangOptions &LangOpts = PP.getLangOptions();
std::string PredefineBuffer;
PredefineBuffer.reserve(4080);
llvm::raw_string_ostream Predefines(PredefineBuffer);
@@ -575,10 +695,27 @@
Builder.append("# 1 \"<built-in>\" 3");
// Install things like __POWERPC__, __GNUC__, etc into the macro table.
- if (InitOpts.UsePredefines)
- InitializePredefinedMacros(PP.getTargetInfo(), PP.getLangOptions(),
- FEOpts, Builder);
+ if (InitOpts.UsePredefines) {
+ InitializePredefinedMacros(PP.getTargetInfo(), LangOpts, FEOpts, Builder);
+ // Install definitions to make Objective-C++ ARC work well with various
+ // C++ Standard Library implementations.
+ if (LangOpts.ObjC1 && LangOpts.CPlusPlus && LangOpts.ObjCAutoRefCount) {
+ switch (InitOpts.ObjCXXARCStandardLibrary) {
+ case ARCXX_nolib:
+ break;
+
+ case ARCXX_libcxx:
+ AddObjCXXARCLibcxxDefines(LangOpts, Builder);
+ break;
+
+ case ARCXX_libstdcxx:
+ AddObjCXXARCLibstdcxxDefines(LangOpts, Builder);
+ break;
+ }
+ }
+ }
+
// Even with predefines off, some macros are still predefined.
// These should all be defined in the preprocessor according to the
// current language configuration.