[libc++] Fix deployment target Lit features (llvm#94791)

We were not making any distinction between e.g. the "Apple-flavored"
libc++ built from trunk and the system-provided standard library on
Apple platforms. For example, any test that would be XFAILed on a
back-deployment target would unexpectedly pass when run on that
deployment target against the tip of trunk Apple-flavored libc++. In
reality, that test would be expected to pass because we're running
against the latest libc++, even if it is Apple-flavored.

To solve this issue, we introduce a new feature that describes whether
the Standard Library in use is the one provided by the system by
default, and that notion is different from the underlying standard
library flavor. We also refactor the existing Lit features to make a
distinction between availability markup and the library we're running
against at runtime, which otherwise limit the flexibility of what we can
express in the test suite. Finally, we refactor some of the
back-deployment versions that were incorrect (such as thinking that LLVM
10 was introduced in macOS 11, when in reality macOS 11 was synced with
LLVM 11).

Fixes llvm#82107

Author: ldionne

libcxx/include/__configuration/availability.h

@@ -95,8 +95,8 @@
 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_PUSH /* nothing */
 #  define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_POP  /* nothing */
 
-#  define _LIBCPP_INTRODUCED_IN_LLVM_10 1
-#  define _LIBCPP_INTRODUCED_IN_LLVM_10_ATTRIBUTE /* nothing */
+#  define _LIBCPP_INTRODUCED_IN_LLVM_11 1
+#  define _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE /* nothing */
 
 #  define _LIBCPP_INTRODUCED_IN_LLVM_12 1
 #  define _LIBCPP_INTRODUCED_IN_LLVM_12_ATTRIBUTE /* nothing */
@@ -159,22 +159,22 @@
 #    define _LIBCPP_INTRODUCED_IN_LLVM_9_ATTRIBUTE_POP  /* nothing */
 #  endif
 
-// LLVM 10
+// LLVM 11
 // clang-format off
 #  if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 110000) ||   \
       (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 140000) || \
       (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 140000) ||         \
       (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 70000)
 // clang-format on
-#    define _LIBCPP_INTRODUCED_IN_LLVM_10 0
-#    define _LIBCPP_INTRODUCED_IN_LLVM_10_ATTRIBUTE                                                                    \
+#    define _LIBCPP_INTRODUCED_IN_LLVM_11 0
+#    define _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE                                                                    \
       __attribute__((availability(macos, strict, introduced = 11.0)))                                                  \
       __attribute__((availability(ios, strict, introduced = 14.0)))                                                    \
       __attribute__((availability(tvos, strict, introduced = 14.0)))                                                   \
       __attribute__((availability(watchos, strict, introduced = 7.0)))
 #  else
-#    define _LIBCPP_INTRODUCED_IN_LLVM_10 1
-#    define _LIBCPP_INTRODUCED_IN_LLVM_10_ATTRIBUTE /* nothing */
+#    define _LIBCPP_INTRODUCED_IN_LLVM_11 1
+#    define _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE /* nothing */
 #  endif
 
 // LLVM 12
@@ -290,8 +290,8 @@
 // which requires shared library support for various operations
 // (see libcxx/src/atomic.cpp). This includes <barier>, <latch>,
 // <semaphore>, and notification functions on std::atomic.
-#define _LIBCPP_AVAILABILITY_HAS_SYNC _LIBCPP_INTRODUCED_IN_LLVM_10
-#define _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INTRODUCED_IN_LLVM_10_ATTRIBUTE
+#define _LIBCPP_AVAILABILITY_HAS_SYNC _LIBCPP_INTRODUCED_IN_LLVM_11
+#define _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INTRODUCED_IN_LLVM_11_ATTRIBUTE
 
 // Enable additional explicit instantiations of iostreams components. This
 // reduces the number of weak definitions generated in programs that use

libcxx/lib/abi/CHANGELOG.TXT

@@ -577,7 +577,7 @@ Version 12.0
   Symbol added: ___cxa_free_dependent_exception
 
 ------------
-Version 10.0
+Version 11.0
 ------------
 
 * 54fa9ecd3088 - [libc++] Implementation of C++20's P1135R6 for libcxx

libcxx/test/configs/apple-libc++-backdeployment.cfg.in

@@ -55,6 +55,7 @@ config.substitutions.append(('%{exec}',
 ))
 
 config.stdlib = 'apple-libc++'
+config.using_system_stdlib = True
 
 libcxx.test.config.configure(
     libcxx.test.params.DEFAULT_PARAMETERS + BACKDEPLOYMENT_PARAMETERS,

libcxx/test/libcxx/atomics/atomics.syn/wait.pass.cpp

@@ -5,10 +5,14 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
+
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: no-threads
-// This bug was first fixed in LLVM 19
+
+// This bug was first fixed in LLVM 19. This can't be XFAIL because
+// the test is a no-op (and would XPASS) on some targets.
 // UNSUPPORTED: using-built-library-before-llvm-19
+
 // XFAIL: availability-synchronization_library-missing
 
 #include <atomic>

libcxx/test/libcxx/input.output/iostreams.base/ios.base/ios.base.cons/dtor.uninitialized.pass.cpp

@@ -10,7 +10,7 @@
 
 // The fix for issue 57964 requires an updated dylib due to explicit
 // instantiations. That means Apple backdeployment targets remain broken.
-// UNSUPPORTED: using-built-library-before-llvm-19
+// XFAIL: using-built-library-before-llvm-19
 
 // <ios>
 

libcxx/test/libcxx/language.support/cxa_deleted_virtual.pass.cpp

@@ -11,7 +11,7 @@
 // Test exporting the symbol: "__cxa_deleted_virtual" in macosx
 // But don't expect the symbol to be exported in previous versions.
 //
-// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx10.{{9|10|11|12|13}}
+// XFAIL: stdlib=system && target={{.+}}-apple-macosx10.{{13|14}}
 
 struct S { virtual void f() = delete; virtual ~S() {} };
 int main(int, char**) {

libcxx/test/libcxx/strings/basic.string/string.capacity/PR53170.pass.cpp

@@ -22,7 +22,7 @@
 // Reported as https://llvm.org/PR53170.
 
 // reserve(n) used to shrink the string until https://llvm.org/D117332 was shipped.
-// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx{{10.9|10.10|10.11|10.12|10.13|10.14|10.15|11.0|12.0}}
+// XFAIL: stdlib=system && target={{.+}}-apple-macosx{{10.9|10.10|10.11|10.12|10.13|10.14|10.15|11.0|12.0}}
 
 #include <string>
 #include <stdexcept>

libcxx/test/libcxx/strings/basic.string/string.capacity/allocation_size.pass.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx{{10.13|10.15|11.0}}
+// XFAIL: stdlib=system && target={{.+}}-apple-macosx{{10.13|10.14|10.15|11.0}}
 
 // <string>
 

libcxx/test/libcxx/thread/thread.condition/PR30202_notify_from_pthread_created_thread.pass.cpp

@@ -14,7 +14,7 @@
 // UNSUPPORTED: c++03
 
 // PR30202 was fixed starting in macosx10.13.
-// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx10.{{9|10|11|12}}
+// XFAIL: stdlib=system && target={{.+}}-apple-macosx10.{{9|10|11|12}}
 
 // <condition_variable>
 

libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.pass.cpp

@@ -11,7 +11,7 @@
 // Until 58a0a70fb2f1, this_thread::sleep_for could sometimes get interrupted
 // by signals and this test would fail spuriously. Disable the test on the
 // corresponding system libraries.
-// XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx10.{{9|10|11}}
+// XFAIL: stdlib=system && target={{.+}}-apple-macosx10.{{9|10|11}}
 
 // ALLOW_RETRIES: 3