release/20.x: [libc++][format] Disables the FTM on older MacOS versions. (#126547) #127232

llvmbot · 2025-02-14T17:41:03Z

Backport fbd92d0

Requested by: @mordante

llvmbot · 2025-02-14T17:41:10Z

@ldionne What do you think about merging this PR to the release branch?

llvmbot · 2025-02-14T17:41:39Z

@llvm/pr-subscribers-libcxx

Author: None (llvmbot)

Changes

Backport fbd92d0

Requested by: @mordante

Full diff: https://github.com/llvm/llvm-project/pull/127232.diff

6 Files Affected:

(modified) libcxx/include/version (+6-2)
(modified) libcxx/test/std/language.support/support.limits/support.limits.general/format.version.compile.pass.cpp (+33-15)
(modified) libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.compile.pass.cpp (+22-10)
(modified) libcxx/test/std/language.support/support.limits/support.limits.general/print.version.compile.pass.cpp (+22-10)
(modified) libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp (+55-25)
(modified) libcxx/utils/generate_feature_test_macro_components.py (+10)

diff --git a/libcxx/include/version b/libcxx/include/version
index 29a71ed574e56..c5966b90c061d 100644
--- a/libcxx/include/version
+++ b/libcxx/include/version
@@ -417,7 +417,9 @@ __cpp_lib_void_t                                        201411L <type_traits>
 # define __cpp_lib_erase_if                             202002L
 # undef  __cpp_lib_execution
 // # define __cpp_lib_execution                            201902L
-# define __cpp_lib_format                               202110L
+# if _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   define __cpp_lib_format                             202110L
+# endif
 # define __cpp_lib_format_uchar                         202311L
 # define __cpp_lib_generic_unordered_lookup             201811L
 # define __cpp_lib_int_pow2                             202002L
@@ -499,7 +501,9 @@ __cpp_lib_void_t                                        201411L <type_traits>
 # undef  __cpp_lib_optional
 # define __cpp_lib_optional                             202110L
 # define __cpp_lib_out_ptr                              202106L
-# define __cpp_lib_print                                202207L
+# if _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   define __cpp_lib_print                              202207L
+# endif
 # undef  __cpp_lib_ranges
 # define __cpp_lib_ranges                               202406L
 // # define __cpp_lib_ranges_as_const                      202207L
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/format.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/format.version.compile.pass.cpp
index 7bb2fa399b094..6a96325661346 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/format.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/format.version.compile.pass.cpp
@@ -68,11 +68,17 @@
 
 #elif TEST_STD_VER == 20
 
-# ifndef __cpp_lib_format
-#   error "__cpp_lib_format should be defined in c++20"
-# endif
-# if __cpp_lib_format != 202110L
-#   error "__cpp_lib_format should have the value 202110L in c++20"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_format
+#     error "__cpp_lib_format should be defined in c++20"
+#   endif
+#   if __cpp_lib_format != 202110L
+#     error "__cpp_lib_format should have the value 202110L in c++20"
+#   endif
+# else
+#   ifdef __cpp_lib_format
+#     error "__cpp_lib_format should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # ifdef __cpp_lib_format_ranges
@@ -88,11 +94,17 @@
 
 #elif TEST_STD_VER == 23
 
-# ifndef __cpp_lib_format
-#   error "__cpp_lib_format should be defined in c++23"
-# endif
-# if __cpp_lib_format != 202110L
-#   error "__cpp_lib_format should have the value 202110L in c++23"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_format
+#     error "__cpp_lib_format should be defined in c++23"
+#   endif
+#   if __cpp_lib_format != 202110L
+#     error "__cpp_lib_format should have the value 202110L in c++23"
+#   endif
+# else
+#   ifdef __cpp_lib_format
+#     error "__cpp_lib_format should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # ifndef __cpp_lib_format_ranges
@@ -111,11 +123,17 @@
 
 #elif TEST_STD_VER > 23
 
-# ifndef __cpp_lib_format
-#   error "__cpp_lib_format should be defined in c++26"
-# endif
-# if __cpp_lib_format != 202110L
-#   error "__cpp_lib_format should have the value 202110L in c++26"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_format
+#     error "__cpp_lib_format should be defined in c++26"
+#   endif
+#   if __cpp_lib_format != 202110L
+#     error "__cpp_lib_format should have the value 202110L in c++26"
+#   endif
+# else
+#   ifdef __cpp_lib_format
+#     error "__cpp_lib_format should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # ifndef __cpp_lib_format_ranges
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.compile.pass.cpp
index 2a42ca080612d..61d7747e4b6d1 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/ostream.version.compile.pass.cpp
@@ -89,11 +89,17 @@
 #   endif
 # endif
 
-# ifndef __cpp_lib_print
-#   error "__cpp_lib_print should be defined in c++23"
-# endif
-# if __cpp_lib_print != 202207L
-#   error "__cpp_lib_print should have the value 202207L in c++23"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_print
+#     error "__cpp_lib_print should be defined in c++23"
+#   endif
+#   if __cpp_lib_print != 202207L
+#     error "__cpp_lib_print should have the value 202207L in c++23"
+#   endif
+# else
+#   ifdef __cpp_lib_print
+#     error "__cpp_lib_print should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 #elif TEST_STD_VER > 23
@@ -111,11 +117,17 @@
 #   endif
 # endif
 
-# ifndef __cpp_lib_print
-#   error "__cpp_lib_print should be defined in c++26"
-# endif
-# if __cpp_lib_print != 202207L
-#   error "__cpp_lib_print should have the value 202207L in c++26"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_print
+#     error "__cpp_lib_print should be defined in c++26"
+#   endif
+#   if __cpp_lib_print != 202207L
+#     error "__cpp_lib_print should have the value 202207L in c++26"
+#   endif
+# else
+#   ifdef __cpp_lib_print
+#     error "__cpp_lib_print should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 #endif // TEST_STD_VER > 23
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/print.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/print.version.compile.pass.cpp
index f4ccea4e86304..c9743cf41ef1e 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/print.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/print.version.compile.pass.cpp
@@ -50,20 +50,32 @@
 
 #elif TEST_STD_VER == 23
 
-# ifndef __cpp_lib_print
-#   error "__cpp_lib_print should be defined in c++23"
-# endif
-# if __cpp_lib_print != 202207L
-#   error "__cpp_lib_print should have the value 202207L in c++23"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_print
+#     error "__cpp_lib_print should be defined in c++23"
+#   endif
+#   if __cpp_lib_print != 202207L
+#     error "__cpp_lib_print should have the value 202207L in c++23"
+#   endif
+# else
+#   ifdef __cpp_lib_print
+#     error "__cpp_lib_print should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 #elif TEST_STD_VER > 23
 
-# ifndef __cpp_lib_print
-#   error "__cpp_lib_print should be defined in c++26"
-# endif
-# if __cpp_lib_print != 202207L
-#   error "__cpp_lib_print should have the value 202207L in c++26"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_print
+#     error "__cpp_lib_print should be defined in c++26"
+#   endif
+#   if __cpp_lib_print != 202207L
+#     error "__cpp_lib_print should have the value 202207L in c++26"
+#   endif
+# else
+#   ifdef __cpp_lib_print
+#     error "__cpp_lib_print should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 #endif // TEST_STD_VER > 23
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
index 8f5788d2bed20..137d6cb428930 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
@@ -3685,11 +3685,17 @@
 #   error "__cpp_lib_flat_set should not be defined before c++23"
 # endif
 
-# ifndef __cpp_lib_format
-#   error "__cpp_lib_format should be defined in c++20"
-# endif
-# if __cpp_lib_format != 202110L
-#   error "__cpp_lib_format should have the value 202110L in c++20"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_format
+#     error "__cpp_lib_format should be defined in c++20"
+#   endif
+#   if __cpp_lib_format != 202110L
+#     error "__cpp_lib_format should have the value 202110L in c++20"
+#   endif
+# else
+#   ifdef __cpp_lib_format
+#     error "__cpp_lib_format should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # ifdef __cpp_lib_format_path
@@ -5146,11 +5152,17 @@
 #   endif
 # endif
 
-# ifndef __cpp_lib_format
-#   error "__cpp_lib_format should be defined in c++23"
-# endif
-# if __cpp_lib_format != 202110L
-#   error "__cpp_lib_format should have the value 202110L in c++23"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_format
+#     error "__cpp_lib_format should be defined in c++23"
+#   endif
+#   if __cpp_lib_format != 202110L
+#     error "__cpp_lib_format should have the value 202110L in c++23"
+#   endif
+# else
+#   ifdef __cpp_lib_format
+#     error "__cpp_lib_format should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # ifdef __cpp_lib_format_path
@@ -5679,11 +5691,17 @@
 #   endif
 # endif
 
-# ifndef __cpp_lib_print
-#   error "__cpp_lib_print should be defined in c++23"
-# endif
-# if __cpp_lib_print != 202207L
-#   error "__cpp_lib_print should have the value 202207L in c++23"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_print
+#     error "__cpp_lib_print should be defined in c++23"
+#   endif
+#   if __cpp_lib_print != 202207L
+#     error "__cpp_lib_print should have the value 202207L in c++23"
+#   endif
+# else
+#   ifdef __cpp_lib_print
+#     error "__cpp_lib_print should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # if !defined(_LIBCPP_VERSION) || _LIBCPP_HAS_LOCALIZATION
@@ -6853,11 +6871,17 @@
 #   endif
 # endif
 
-# ifndef __cpp_lib_format
-#   error "__cpp_lib_format should be defined in c++26"
-# endif
-# if __cpp_lib_format != 202110L
-#   error "__cpp_lib_format should have the value 202110L in c++26"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_format
+#     error "__cpp_lib_format should be defined in c++26"
+#   endif
+#   if __cpp_lib_format != 202110L
+#     error "__cpp_lib_format should have the value 202110L in c++26"
+#   endif
+# else
+#   ifdef __cpp_lib_format
+#     error "__cpp_lib_format should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # if !defined(_LIBCPP_VERSION)
@@ -7557,11 +7581,17 @@
 #   endif
 # endif
 
-# ifndef __cpp_lib_print
-#   error "__cpp_lib_print should be defined in c++26"
-# endif
-# if __cpp_lib_print != 202207L
-#   error "__cpp_lib_print should have the value 202207L in c++26"
+# if !defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT
+#   ifndef __cpp_lib_print
+#     error "__cpp_lib_print should be defined in c++26"
+#   endif
+#   if __cpp_lib_print != 202207L
+#     error "__cpp_lib_print should have the value 202207L in c++26"
+#   endif
+# else
+#   ifdef __cpp_lib_print
+#     error "__cpp_lib_print should not be defined when the requirement '!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT' is not met!"
+#   endif
 # endif
 
 # if !defined(_LIBCPP_VERSION) || _LIBCPP_HAS_LOCALIZATION
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
index 58ecd79cf7469..00318c2d2a3cd 100755
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -529,6 +529,11 @@ def add_version_header(tc):
             # 202305 P2757R3 Type-checking format args
             # 202306 P2637R3 Member Visit
             "headers": ["format"],
+            # Trying to use `std::format` where to_chars floating-point is not
+            # available causes compilation errors, even with non floating-point types.
+            # https://github.com/llvm/llvm-project/issues/125353
+            "test_suite_guard": "!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT",
+            "libcxx_guard": "_LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT",
         },
         {
             "name": "__cpp_lib_format_path",
@@ -1004,6 +1009,11 @@ def add_version_header(tc):
                 # "c++26": 202406, # P3235R3 std::print more types faster with less memory
             },
             "headers": ["ostream", "print"],
+            # Trying to use `std::print` where to_chars floating-point is not
+            # available causes compilation errors, even with non floating-point types.
+            # https://github.com/llvm/llvm-project/issues/125353
+            "test_suite_guard": "!defined(_LIBCPP_VERSION) || _LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT",
+            "libcxx_guard": "_LIBCPP_AVAILABILITY_HAS_TO_CHARS_FLOATING_POINT",
         },
         {
             "name": "__cpp_lib_quoted_string_io",

On older MacOS versions where `std::to_chars` for floating-point types is not available the format library can't be used. Due to some issue with the availability macro used to disable format on MacOS the issue triggers regardless of the type being formatted. The print library has the same issue. Fixes: llvm#125353 (cherry picked from commit fbd92d0)

github-actions · 2025-02-16T06:11:47Z

@mordante (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.

llvmbot requested a review from a team as a code owner February 14, 2025 17:41

llvmbot added this to the LLVM 20.X Release milestone Feb 14, 2025

llvmbot requested a review from ldionne February 14, 2025 17:41

llvmbot mentioned this pull request Feb 14, 2025

[libc++][format] Disables the FTM on older MacOS versions. #126547

Merged

llvmbot added the libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi. label Feb 14, 2025

ldionne approved these changes Feb 15, 2025

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llvmbot force-pushed the issue126547 branch from 0ee16ae to 8b73dad Compare February 16, 2025 06:10

tstellar merged commit 8b73dad into llvm:release/20.x Feb 16, 2025
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release/20.x: [libc++][format] Disables the FTM on older MacOS versions. (#126547) #127232

release/20.x: [libc++][format] Disables the FTM on older MacOS versions. (#126547) #127232

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release/20.x: [libc++][format] Disables the FTM on older MacOS versions. (#126547) #127232

release/20.x: [libc++][format] Disables the FTM on older MacOS versions. (#126547) #127232

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