[PATCH v4 2/6] compiler.h: Introduce TYPEOF_UNQUAL() macro
From: Uros Bizjak <hidden>
Date: 2025-01-27 16:07:25
Also in:
linux-arch, linux-bcachefs, linux-mm, lkml
Subsystem:
clang/llvm build support, sparse checker, the rest · Maintainers:
Nathan Chancellor, Chris Li, Linus Torvalds
Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof operator
when available, to return unqualified type of the expression.
Current version of sparse doesn't know anything about __typeof_unqual__()
operator. Avoid the usage of __typeof_unqual__() when sparse checking
is active to prevent sparse errors with unknowing keyword.
Signed-off-by: Uros Bizjak <redacted>
Cc: Thomas Gleixner <redacted>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <redacted>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <redacted>
Cc: Denys Vlasenko <redacted>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
v2: - Add comment to remove test for __CHECKER__ once sparse learns
about __typeof_unqual__.
v4: - Do not auto-detect compiler support for __typeof_unqual__()
---
include/linux/compiler-clang.h | 8 ++++++++
include/linux/compiler-gcc.h | 8 ++++++++
include/linux/compiler.h | 20 ++++++++++++++++++++
3 files changed, 36 insertions(+)
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 2e7c2c282f3a..4fc8e26914ad 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h@@ -128,3 +128,11 @@ */ #define ASM_INPUT_G "ir" #define ASM_INPUT_RM "r" + +/* + * Declare compiler support for __typeof_unqual__() operator. + * + * Bindgen uses LLVM even if our C compiler is GCC, so we cannot + * rely on the auto-detected CONFIG_CC_HAS_TYPEOF_UNQUAL. + */ +#define CC_HAS_TYPEOF_UNQUAL (__clang_major__ >= 19)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index c9b58188ec61..32048052c64a 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h@@ -137,3 +137,11 @@ #if GCC_VERSION < 90100 #undef __alloc_size__ #endif + +/* + * Declare compiler support for __typeof_unqual__() operator. + * + * Bindgen uses LLVM even if our C compiler is GCC, so we cannot + * rely on the auto-detected CONFIG_CC_HAS_TYPEOF_UNQUAL. + */ +#define CC_HAS_TYPEOF_UNQUAL (__GNUC__ >= 14)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index b087de2f3e94..a892c89ac28a 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h@@ -191,6 +191,26 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, __v; \ }) +/* + * Use __typeof_unqual__() when available. + * + * XXX: Remove test for __CHECKER__ once + * sparse learns about __typeof_unqual__(). + */ +#if CC_HAS_TYPEOF_UNQUAL && !defined(__CHECKER__) +# define USE_TYPEOF_UNQUAL 1 +#endif + +/* + * Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof + * operator when available, to return an unqualified type of the exp. + */ +#if defined(USE_TYPEOF_UNQUAL) +# define TYPEOF_UNQUAL(exp) __typeof_unqual__(exp) +#else +# define TYPEOF_UNQUAL(exp) __typeof__(exp) +#endif + #endif /* __KERNEL__ */ /**
--
2.42.0