[clang] [C23] Fixed the value of BOOL_WIDTH (PR #117364)
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Mon Nov 25 04:21:43 PST 2024
https://github.com/AaronBallman updated https://github.com/llvm/llvm-project/pull/117364
>From 37923ec9c6a0bbabd2640f7e95549bf560974e59 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Fri, 22 Nov 2024 14:18:33 -0500
Subject: [PATCH 1/2] [C23] Fixed the value of BOOL_WIDTH
---
clang/docs/ReleaseNotes.rst | 2 ++
clang/lib/Frontend/InitPreprocessor.cpp | 10 ++++++++-
clang/test/C/C23/n2412.c | 27 ++++++++++++++++++++++++
clang/test/Preprocessor/init-aarch64.c | 4 ++--
clang/test/Preprocessor/init-loongarch.c | 4 ++--
clang/test/Preprocessor/init.c | 2 +-
6 files changed, 43 insertions(+), 6 deletions(-)
create mode 100644 clang/test/C/C23/n2412.c
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8bd06fadfdc984..ff8c2f92e875f8 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -332,6 +332,8 @@ C23 Feature Support
- Clang now supports `N3029 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3029.htm>`_ Improved Normal Enumerations.
- Clang now officially supports `N3030 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3030.htm>`_ Enhancements to Enumerations. Clang already supported it as an extension, so there were no changes to compiler behavior.
+- Fixed the value of ``BOOL_WIDTH`` in ``<limits.h>`` to return ``1``
+ explicitly, as mandated by the standard.
Non-comprehensive list of changes in this release
-------------------------------------------------
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 9a0fdb175ff29e..6ecb201fd46970 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1103,7 +1103,15 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
assert(TI.getCharWidth() == 8 && "Only support 8-bit char so far");
Builder.defineMacro("__CHAR_BIT__", Twine(TI.getCharWidth()));
- Builder.defineMacro("__BOOL_WIDTH__", Twine(TI.getBoolWidth()));
+ // The macro is specifying the number of bits in the value representation,
+ // not the number of bits in the object representation, which is what
+ // getBoolWidth() will return. For the bool/_Bool data type, there is only
+ // ever one bit in the value representation. See C23 6.2.6.2p2 for the rules
+ // in C. Note that [basic.fundamental]p10 allows an implementation-defined
+ // value representation for bool; Clang represents bool as an i1 when
+ // lowering to LLVM, so this value is also correct for C++ for our
+ // implementation.
+ Builder.defineMacro("__BOOL_WIDTH__", "1");
Builder.defineMacro("__SHRT_WIDTH__", Twine(TI.getShortWidth()));
Builder.defineMacro("__INT_WIDTH__", Twine(TI.getIntWidth()));
Builder.defineMacro("__LONG_WIDTH__", Twine(TI.getLongWidth()));
diff --git a/clang/test/C/C23/n2412.c b/clang/test/C/C23/n2412.c
new file mode 100644
index 00000000000000..7d4f32ae68a734
--- /dev/null
+++ b/clang/test/C/C23/n2412.c
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -verify -std=c23 -ffreestanding %s
+
+/* WG14 N2412: Clang 14
+ * Two's complement sign representation
+ */
+// expected-no-diagnostics
+
+#include <limits.h>
+
+// GH117348 -- BOOL_WIDTH was accidentally expanding to the number of bits in
+// the object representation (8) rather than the number of bits in the value
+// representation (1).
+static_assert(BOOL_WIDTH == 1);
+
+// Validate the other macro requirements.
+static_assert(CHAR_WIDTH == SCHAR_WIDTH);
+static_assert(CHAR_WIDTH == UCHAR_WIDTH);
+static_assert(CHAR_WIDTH == CHAR_BIT);
+
+static_assert(USHRT_WIDTH >= 16);
+static_assert(UINT_WIDTH >= 16);
+static_assert(ULONG_WIDTH >= 32);
+static_assert(ULLONG_WIDTH >= 64);
+static_assert(BITINT_MAXWIDTH >= ULLONG_WIDTH);
+
+static_assert(MB_LEN_MAX >= 1);
+
diff --git a/clang/test/Preprocessor/init-aarch64.c b/clang/test/Preprocessor/init-aarch64.c
index c52c49a94e016e..8ee6c6ba60af43 100644
--- a/clang/test/Preprocessor/init-aarch64.c
+++ b/clang/test/Preprocessor/init-aarch64.c
@@ -44,7 +44,7 @@
// AARCH64: #define __BIGGEST_ALIGNMENT__ 16
// AARCH64_BE-NEXT: #define __BIG_ENDIAN__ 1
// AARCH64-NEXT: #define __BITINT_MAXWIDTH__ 128
-// AARCH64-NEXT: #define __BOOL_WIDTH__ 8
+// AARCH64-NEXT: #define __BOOL_WIDTH__ 1
// AARCH64_BE-NEXT: #define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__
// AARCH64_LE-NEXT: #define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
// AARCH64-NEXT: #define __CHAR16_TYPE__ unsigned short
@@ -785,7 +785,7 @@
// ARM64EC-MSVC: #define __ATOMIC_SEQ_CST 5
// ARM64EC-MSVC: #define __BIGGEST_ALIGNMENT__ 16
// ARM64EC-MSVC: #define __BITINT_MAXWIDTH__ 128
-// ARM64EC-MSVC: #define __BOOL_WIDTH__ 8
+// ARM64EC-MSVC: #define __BOOL_WIDTH__ 1
// ARM64EC-MSVC: #define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
// ARM64EC-MSVC: #define __CHAR16_TYPE__ unsigned short
// ARM64EC-MSVC: #define __CHAR32_TYPE__ unsigned int
diff --git a/clang/test/Preprocessor/init-loongarch.c b/clang/test/Preprocessor/init-loongarch.c
index 0eb6977a2553c9..0e3320f01b328c 100644
--- a/clang/test/Preprocessor/init-loongarch.c
+++ b/clang/test/Preprocessor/init-loongarch.c
@@ -25,7 +25,7 @@
// LA32-NEXT: #define __ATOMIC_SEQ_CST 5
// LA32: #define __BIGGEST_ALIGNMENT__ 16
// LA32: #define __BITINT_MAXWIDTH__ 128
-// LA32: #define __BOOL_WIDTH__ 8
+// LA32: #define __BOOL_WIDTH__ 1
// LA32: #define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
// LA32: #define __CHAR16_TYPE__ unsigned short
// LA32: #define __CHAR32_TYPE__ unsigned int
@@ -346,7 +346,7 @@
// LA64-NEXT: #define __ATOMIC_SEQ_CST 5
// LA64: #define __BIGGEST_ALIGNMENT__ 16
// LA64: #define __BITINT_MAXWIDTH__ 128
-// LA64: #define __BOOL_WIDTH__ 8
+// LA64: #define __BOOL_WIDTH__ 1
// LA64: #define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
// LA64: #define __CHAR16_TYPE__ unsigned short
// LA64: #define __CHAR32_TYPE__ unsigned int
diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
index c177975114332a..05225c120b13de 100644
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -1617,7 +1617,7 @@
// WEBASSEMBLY-NEXT:#define __ATOMIC_SEQ_CST 5
// WEBASSEMBLY-NEXT:#define __BIGGEST_ALIGNMENT__ 16
// WEBASSEMBLY-NEXT:#define __BITINT_MAXWIDTH__ 128
-// WEBASSEMBLY-NEXT:#define __BOOL_WIDTH__ 8
+// WEBASSEMBLY-NEXT:#define __BOOL_WIDTH__ 1
// WEBASSEMBLY-NEXT:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
// WEBASSEMBLY-NEXT:#define __CHAR16_TYPE__ unsigned short
// WEBASSEMBLY-NEXT:#define __CHAR32_TYPE__ unsigned int
>From b5b4d4eed1ee430fa6c23905b44c81d137c86570 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Fri, 22 Nov 2024 14:21:06 -0500
Subject: [PATCH 2/2] Update release note to mention this fixes a user-reported
issue
---
clang/docs/ReleaseNotes.rst | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index ff8c2f92e875f8..d26e1739213d09 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -333,7 +333,7 @@ C23 Feature Support
- Clang now supports `N3029 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3029.htm>`_ Improved Normal Enumerations.
- Clang now officially supports `N3030 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3030.htm>`_ Enhancements to Enumerations. Clang already supported it as an extension, so there were no changes to compiler behavior.
- Fixed the value of ``BOOL_WIDTH`` in ``<limits.h>`` to return ``1``
- explicitly, as mandated by the standard.
+ explicitly, as mandated by the standard. Fixes #GH117348
Non-comprehensive list of changes in this release
-------------------------------------------------
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