[clang] 0077048 - [C23] Fixed the value of BOOL_WIDTH (#117364)
via cfe-commits
cfe-commits at lists.llvm.org
Mon Nov 25 10:01:29 PST 2024
Author: Aaron Ballman
Date: 2024-11-25T13:01:25-05:00
New Revision: 00770489e4299fe6ab99b1772127d84dfe222ffc
URL: https://github.com/llvm/llvm-project/commit/00770489e4299fe6ab99b1772127d84dfe222ffc
DIFF: https://github.com/llvm/llvm-project/commit/00770489e4299fe6ab99b1772127d84dfe222ffc.diff
LOG: [C23] Fixed the value of BOOL_WIDTH (#117364)
The standard mandates that this returns the width of the type, which is
the number of bits in the value. For bool, that's required to be `1`
explicitly.
Fixes #117348
Added:
clang/test/C/C23/n2412.c
Modified:
clang/docs/ReleaseNotes.rst
clang/lib/Frontend/InitPreprocessor.cpp
clang/test/Preprocessor/init-aarch64.c
clang/test/Preprocessor/init-loongarch.c
clang/test/Preprocessor/init.c
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index b9986434d09d24..954fe61f3d1d69 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. Fixes #GH117348
Non-comprehensive list of changes in this release
-------------------------------------------------
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 9a0fdb175ff29e..9b611bfcc9e637 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 width, not the number of
+ // bits the object requires for its in-memory representation, which is what
+ // getBoolWidth() will return. The bool/_Bool data type is only ever one bit
+ // wide. See C23 6.2.6.2p2 for the rules in C. Note that
+ // C++23 [basic.fundamental]p10 allows an implementation-defined value
+ // representation for bool; when lowering to LLVM, Clang represents bool as an
+ // i8 in memory but as an i1 when the value is needed, so '1' is also correct
+ // for C++.
+ 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
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