From d44b7b7d312b1d4b920042cac35b86e4f089cd04 Mon Sep 17 00:00:00 2001 From: Daniel Golle Date: Fri, 1 Jun 2018 15:25:42 +0200 Subject: [PATCH] uboot-oxnas: fix build with newer GCC Signed-off-by: Daniel Golle --- .../patches/410-gcc-6-compiler.patch | 306 ++++++++++++++++++ .../patches/420-gcc-7-compiler.patch | 287 ++++++++++++++++ 2 files changed, 593 insertions(+) create mode 100644 package/boot/uboot-oxnas/patches/410-gcc-6-compiler.patch create mode 100644 package/boot/uboot-oxnas/patches/420-gcc-7-compiler.patch diff --git a/package/boot/uboot-oxnas/patches/410-gcc-6-compiler.patch b/package/boot/uboot-oxnas/patches/410-gcc-6-compiler.patch new file mode 100644 index 0000000000..00d0657bd6 --- /dev/null +++ b/package/boot/uboot-oxnas/patches/410-gcc-6-compiler.patch @@ -0,0 +1,306 @@ +From: Hans de Goede +Date: Sat, 7 Feb 2015 21:52:40 +0000 (+0100) +Subject: Add linux/compiler-gcc6.h to fix builds with gcc6 +X-Git-Tag: v2015.04-rc2~31 +X-Git-Url: http://git.denx.de/?p=u-boot.git;a=commitdiff_plain;h=478b02f1a7043b673565075ea5016376f3293b23 + +Add linux/compiler-gcc6.h to fix builds with gcc6 + +Add linux/compiler-gcc6/h from the kernel sources at: + +commit 5631b8fba640a4ab2f8a954f63a603fa34eda96b +Author: Steven Noonan +Date: Sat Oct 25 15:09:42 2014 -0700 + + compiler/gcc4+: Remove inaccurate comment about 'asm goto' miscompiles + +Signed-off-by: Hans de Goede +--- + +--- /dev/null ++++ b/include/linux/compiler-gcc6.h +@@ -0,0 +1,284 @@ ++#ifndef __LINUX_COMPILER_H ++#error "Please don't include directly, include instead." ++#endif ++ ++/* ++ * Common definitions for all gcc versions go here. ++ */ ++#define GCC_VERSION (__GNUC__ * 10000 \ ++ + __GNUC_MINOR__ * 100 \ ++ + __GNUC_PATCHLEVEL__) ++ ++/* Optimization barrier */ ++ ++/* The "volatile" is due to gcc bugs */ ++#define barrier() __asm__ __volatile__("": : :"memory") ++/* ++ * This version is i.e. to prevent dead stores elimination on @ptr ++ * where gcc and llvm may behave differently when otherwise using ++ * normal barrier(): while gcc behavior gets along with a normal ++ * barrier(), llvm needs an explicit input variable to be assumed ++ * clobbered. The issue is as follows: while the inline asm might ++ * access any memory it wants, the compiler could have fit all of ++ * @ptr into memory registers instead, and since @ptr never escaped ++ * from that, it proofed that the inline asm wasn't touching any of ++ * it. This version works well with both compilers, i.e. we're telling ++ * the compiler that the inline asm absolutely may see the contents ++ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 ++ */ ++#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") ++ ++/* ++ * This macro obfuscates arithmetic on a variable address so that gcc ++ * shouldn't recognize the original var, and make assumptions about it. ++ * ++ * This is needed because the C standard makes it undefined to do ++ * pointer arithmetic on "objects" outside their boundaries and the ++ * gcc optimizers assume this is the case. In particular they ++ * assume such arithmetic does not wrap. ++ * ++ * A miscompilation has been observed because of this on PPC. ++ * To work around it we hide the relationship of the pointer and the object ++ * using this macro. ++ * ++ * Versions of the ppc64 compiler before 4.1 had a bug where use of ++ * RELOC_HIDE could trash r30. The bug can be worked around by changing ++ * the inline assembly constraint from =g to =r, in this particular ++ * case either is valid. ++ */ ++#define RELOC_HIDE(ptr, off) \ ++({ \ ++ unsigned long __ptr; \ ++ __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ ++ (typeof(ptr)) (__ptr + (off)); \ ++}) ++ ++/* Make the optimizer believe the variable can be manipulated arbitrarily. */ ++#define OPTIMIZER_HIDE_VAR(var) \ ++ __asm__ ("" : "=r" (var) : "0" (var)) ++ ++#ifdef __CHECKER__ ++#define __must_be_array(a) 0 ++#else ++/* &a[0] degrades to a pointer: a different type from an array */ ++#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) ++#endif ++ ++/* ++ * Force always-inline if the user requests it so via the .config, ++ * or if gcc is too old: ++ */ ++#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ ++ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) ++#define inline inline __attribute__((always_inline)) notrace ++#define __inline__ __inline__ __attribute__((always_inline)) notrace ++#define __inline __inline __attribute__((always_inline)) notrace ++#else ++/* A lot of inline functions can cause havoc with function tracing */ ++#define inline inline notrace ++#define __inline__ __inline__ notrace ++#define __inline __inline notrace ++#endif ++ ++#define __always_inline inline __attribute__((always_inline)) ++#define noinline __attribute__((noinline)) ++ ++#define __deprecated __attribute__((deprecated)) ++#define __packed __attribute__((packed)) ++#define __weak __attribute__((weak)) ++#define __alias(symbol) __attribute__((alias(#symbol))) ++ ++/* ++ * it doesn't make sense on ARM (currently the only user of __naked) ++ * to trace naked functions because then mcount is called without ++ * stack and frame pointer being set up and there is no chance to ++ * restore the lr register to the value before mcount was called. ++ * ++ * The asm() bodies of naked functions often depend on standard calling ++ * conventions, therefore they must be noinline and noclone. ++ * ++ * GCC 4.[56] currently fail to enforce this, so we must do so ourselves. ++ * See GCC PR44290. ++ */ ++#define __naked __attribute__((naked)) noinline __noclone notrace ++ ++#define __noreturn __attribute__((noreturn)) ++ ++/* ++ * From the GCC manual: ++ * ++ * Many functions have no effects except the return value and their ++ * return value depends only on the parameters and/or global ++ * variables. Such a function can be subject to common subexpression ++ * elimination and loop optimization just as an arithmetic operator ++ * would be. ++ * [...] ++ */ ++#define __pure __attribute__((pure)) ++#define __aligned(x) __attribute__((aligned(x))) ++#define __printf(a, b) __attribute__((format(printf, a, b))) ++#define __scanf(a, b) __attribute__((format(scanf, a, b))) ++#define __attribute_const__ __attribute__((__const__)) ++#define __maybe_unused __attribute__((unused)) ++#define __always_unused __attribute__((unused)) ++ ++/* gcc version specific checks */ ++ ++#if GCC_VERSION < 30200 ++# error Sorry, your compiler is too old - please upgrade it. ++#endif ++ ++#if GCC_VERSION < 30300 ++# define __used __attribute__((__unused__)) ++#else ++# define __used __attribute__((__used__)) ++#endif ++ ++#ifdef CONFIG_GCOV_KERNEL ++# if GCC_VERSION < 30400 ++# error "GCOV profiling support for gcc versions below 3.4 not included" ++# endif /* __GNUC_MINOR__ */ ++#endif /* CONFIG_GCOV_KERNEL */ ++ ++#if GCC_VERSION >= 30400 ++#define __must_check __attribute__((warn_unused_result)) ++#define __malloc __attribute__((__malloc__)) ++#endif ++ ++#if GCC_VERSION >= 40000 ++ ++/* GCC 4.1.[01] miscompiles __weak */ ++#ifdef __KERNEL__ ++# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 ++# error Your version of gcc miscompiles the __weak directive ++# endif ++#endif ++ ++#define __used __attribute__((__used__)) ++#define __compiler_offsetof(a, b) \ ++ __builtin_offsetof(a, b) ++ ++#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 ++# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) ++#endif ++ ++#if GCC_VERSION >= 40300 ++/* Mark functions as cold. gcc will assume any path leading to a call ++ * to them will be unlikely. This means a lot of manual unlikely()s ++ * are unnecessary now for any paths leading to the usual suspects ++ * like BUG(), printk(), panic() etc. [but let's keep them for now for ++ * older compilers] ++ * ++ * Early snapshots of gcc 4.3 don't support this and we can't detect this ++ * in the preprocessor, but we can live with this because they're unreleased. ++ * Maketime probing would be overkill here. ++ * ++ * gcc also has a __attribute__((__hot__)) to move hot functions into ++ * a special section, but I don't see any sense in this right now in ++ * the kernel context ++ */ ++#define __cold __attribute__((__cold__)) ++ ++#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) ++ ++#ifndef __CHECKER__ ++# define __compiletime_warning(message) __attribute__((warning(message))) ++# define __compiletime_error(message) __attribute__((error(message))) ++#endif /* __CHECKER__ */ ++#endif /* GCC_VERSION >= 40300 */ ++ ++#if GCC_VERSION >= 40500 ++/* ++ * Mark a position in code as unreachable. This can be used to ++ * suppress control flow warnings after asm blocks that transfer ++ * control elsewhere. ++ * ++ * Early snapshots of gcc 4.5 don't support this and we can't detect ++ * this in the preprocessor, but we can live with this because they're ++ * unreleased. Really, we need to have autoconf for the kernel. ++ */ ++#define unreachable() __builtin_unreachable() ++ ++/* Mark a function definition as prohibited from being cloned. */ ++#define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) ++ ++#endif /* GCC_VERSION >= 40500 */ ++ ++#if GCC_VERSION >= 40600 ++/* ++ * When used with Link Time Optimization, gcc can optimize away C functions or ++ * variables which are referenced only from assembly code. __visible tells the ++ * optimizer that something else uses this function or variable, thus preventing ++ * this. ++ */ ++#define __visible __attribute__((externally_visible)) ++#endif ++ ++ ++#if GCC_VERSION >= 40900 && !defined(__CHECKER__) ++/* ++ * __assume_aligned(n, k): Tell the optimizer that the returned ++ * pointer can be assumed to be k modulo n. The second argument is ++ * optional (default 0), so we use a variadic macro to make the ++ * shorthand. ++ * ++ * Beware: Do not apply this to functions which may return ++ * ERR_PTRs. Also, it is probably unwise to apply it to functions ++ * returning extra information in the low bits (but in that case the ++ * compiler should see some alignment anyway, when the return value is ++ * massaged by 'flags = ptr & 3; ptr &= ~3;'). ++ */ ++#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) ++#endif ++ ++/* ++ * GCC 'asm goto' miscompiles certain code sequences: ++ * ++ * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 ++ * ++ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. ++ * ++ * (asm goto is automatically volatile - the naming reflects this.) ++ */ ++#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) ++ ++#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP ++#if GCC_VERSION >= 40400 ++#define __HAVE_BUILTIN_BSWAP32__ ++#define __HAVE_BUILTIN_BSWAP64__ ++#endif ++#if GCC_VERSION >= 40800 ++#define __HAVE_BUILTIN_BSWAP16__ ++#endif ++#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ ++ ++#if GCC_VERSION >= 50000 ++#define KASAN_ABI_VERSION 4 ++#elif GCC_VERSION >= 40902 ++#define KASAN_ABI_VERSION 3 ++#endif ++ ++#if GCC_VERSION >= 40902 ++/* ++ * Tell the compiler that address safety instrumentation (KASAN) ++ * should not be applied to that function. ++ * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 ++ */ ++#define __no_sanitize_address __attribute__((no_sanitize_address)) ++#endif ++ ++#endif /* gcc version >= 40000 specific checks */ ++ ++#if !defined(__noclone) ++#define __noclone /* not needed */ ++#endif ++ ++#if !defined(__no_sanitize_address) ++#define __no_sanitize_address ++#endif ++ ++/* ++ * A trick to suppress uninitialized variable warning without generating any ++ * code ++ */ ++#define uninitialized_var(x) x = x diff --git a/package/boot/uboot-oxnas/patches/420-gcc-7-compiler.patch b/package/boot/uboot-oxnas/patches/420-gcc-7-compiler.patch new file mode 100644 index 0000000000..0951629642 --- /dev/null +++ b/package/boot/uboot-oxnas/patches/420-gcc-7-compiler.patch @@ -0,0 +1,287 @@ +--- /dev/null ++++ b/include/linux/compiler-gcc7.h +@@ -0,0 +1,284 @@ ++#ifndef __LINUX_COMPILER_H ++#error "Please don't include directly, include instead." ++#endif ++ ++/* ++ * Common definitions for all gcc versions go here. ++ */ ++#define GCC_VERSION (__GNUC__ * 10000 \ ++ + __GNUC_MINOR__ * 100 \ ++ + __GNUC_PATCHLEVEL__) ++ ++/* Optimization barrier */ ++ ++/* The "volatile" is due to gcc bugs */ ++#define barrier() __asm__ __volatile__("": : :"memory") ++/* ++ * This version is i.e. to prevent dead stores elimination on @ptr ++ * where gcc and llvm may behave differently when otherwise using ++ * normal barrier(): while gcc behavior gets along with a normal ++ * barrier(), llvm needs an explicit input variable to be assumed ++ * clobbered. The issue is as follows: while the inline asm might ++ * access any memory it wants, the compiler could have fit all of ++ * @ptr into memory registers instead, and since @ptr never escaped ++ * from that, it proofed that the inline asm wasn't touching any of ++ * it. This version works well with both compilers, i.e. we're telling ++ * the compiler that the inline asm absolutely may see the contents ++ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495 ++ */ ++#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory") ++ ++/* ++ * This macro obfuscates arithmetic on a variable address so that gcc ++ * shouldn't recognize the original var, and make assumptions about it. ++ * ++ * This is needed because the C standard makes it undefined to do ++ * pointer arithmetic on "objects" outside their boundaries and the ++ * gcc optimizers assume this is the case. In particular they ++ * assume such arithmetic does not wrap. ++ * ++ * A miscompilation has been observed because of this on PPC. ++ * To work around it we hide the relationship of the pointer and the object ++ * using this macro. ++ * ++ * Versions of the ppc64 compiler before 4.1 had a bug where use of ++ * RELOC_HIDE could trash r30. The bug can be worked around by changing ++ * the inline assembly constraint from =g to =r, in this particular ++ * case either is valid. ++ */ ++#define RELOC_HIDE(ptr, off) \ ++({ \ ++ unsigned long __ptr; \ ++ __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ ++ (typeof(ptr)) (__ptr + (off)); \ ++}) ++ ++/* Make the optimizer believe the variable can be manipulated arbitrarily. */ ++#define OPTIMIZER_HIDE_VAR(var) \ ++ __asm__ ("" : "=r" (var) : "0" (var)) ++ ++#ifdef __CHECKER__ ++#define __must_be_array(a) 0 ++#else ++/* &a[0] degrades to a pointer: a different type from an array */ ++#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) ++#endif ++ ++/* ++ * Force always-inline if the user requests it so via the .config, ++ * or if gcc is too old: ++ */ ++#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ ++ !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4) ++#define inline inline __attribute__((always_inline)) notrace ++#define __inline__ __inline__ __attribute__((always_inline)) notrace ++#define __inline __inline __attribute__((always_inline)) notrace ++#else ++/* A lot of inline functions can cause havoc with function tracing */ ++#define inline inline notrace ++#define __inline__ __inline__ notrace ++#define __inline __inline notrace ++#endif ++ ++#define __always_inline inline __attribute__((always_inline)) ++#define noinline __attribute__((noinline)) ++ ++#define __deprecated __attribute__((deprecated)) ++#define __packed __attribute__((packed)) ++#define __weak __attribute__((weak)) ++#define __alias(symbol) __attribute__((alias(#symbol))) ++ ++/* ++ * it doesn't make sense on ARM (currently the only user of __naked) ++ * to trace naked functions because then mcount is called without ++ * stack and frame pointer being set up and there is no chance to ++ * restore the lr register to the value before mcount was called. ++ * ++ * The asm() bodies of naked functions often depend on standard calling ++ * conventions, therefore they must be noinline and noclone. ++ * ++ * GCC 4.[56] currently fail to enforce this, so we must do so ourselves. ++ * See GCC PR44290. ++ */ ++#define __naked __attribute__((naked)) noinline __noclone notrace ++ ++#define __noreturn __attribute__((noreturn)) ++ ++/* ++ * From the GCC manual: ++ * ++ * Many functions have no effects except the return value and their ++ * return value depends only on the parameters and/or global ++ * variables. Such a function can be subject to common subexpression ++ * elimination and loop optimization just as an arithmetic operator ++ * would be. ++ * [...] ++ */ ++#define __pure __attribute__((pure)) ++#define __aligned(x) __attribute__((aligned(x))) ++#define __printf(a, b) __attribute__((format(printf, a, b))) ++#define __scanf(a, b) __attribute__((format(scanf, a, b))) ++#define __attribute_const__ __attribute__((__const__)) ++#define __maybe_unused __attribute__((unused)) ++#define __always_unused __attribute__((unused)) ++ ++/* gcc version specific checks */ ++ ++#if GCC_VERSION < 30200 ++# error Sorry, your compiler is too old - please upgrade it. ++#endif ++ ++#if GCC_VERSION < 30300 ++# define __used __attribute__((__unused__)) ++#else ++# define __used __attribute__((__used__)) ++#endif ++ ++#ifdef CONFIG_GCOV_KERNEL ++# if GCC_VERSION < 30400 ++# error "GCOV profiling support for gcc versions below 3.4 not included" ++# endif /* __GNUC_MINOR__ */ ++#endif /* CONFIG_GCOV_KERNEL */ ++ ++#if GCC_VERSION >= 30400 ++#define __must_check __attribute__((warn_unused_result)) ++#define __malloc __attribute__((__malloc__)) ++#endif ++ ++#if GCC_VERSION >= 40000 ++ ++/* GCC 4.1.[01] miscompiles __weak */ ++#ifdef __KERNEL__ ++# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 ++# error Your version of gcc miscompiles the __weak directive ++# endif ++#endif ++ ++#define __used __attribute__((__used__)) ++#define __compiler_offsetof(a, b) \ ++ __builtin_offsetof(a, b) ++ ++#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 ++# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) ++#endif ++ ++#if GCC_VERSION >= 40300 ++/* Mark functions as cold. gcc will assume any path leading to a call ++ * to them will be unlikely. This means a lot of manual unlikely()s ++ * are unnecessary now for any paths leading to the usual suspects ++ * like BUG(), printk(), panic() etc. [but let's keep them for now for ++ * older compilers] ++ * ++ * Early snapshots of gcc 4.3 don't support this and we can't detect this ++ * in the preprocessor, but we can live with this because they're unreleased. ++ * Maketime probing would be overkill here. ++ * ++ * gcc also has a __attribute__((__hot__)) to move hot functions into ++ * a special section, but I don't see any sense in this right now in ++ * the kernel context ++ */ ++#define __cold __attribute__((__cold__)) ++ ++#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) ++ ++#ifndef __CHECKER__ ++# define __compiletime_warning(message) __attribute__((warning(message))) ++# define __compiletime_error(message) __attribute__((error(message))) ++#endif /* __CHECKER__ */ ++#endif /* GCC_VERSION >= 40300 */ ++ ++#if GCC_VERSION >= 40500 ++/* ++ * Mark a position in code as unreachable. This can be used to ++ * suppress control flow warnings after asm blocks that transfer ++ * control elsewhere. ++ * ++ * Early snapshots of gcc 4.5 don't support this and we can't detect ++ * this in the preprocessor, but we can live with this because they're ++ * unreleased. Really, we need to have autoconf for the kernel. ++ */ ++#define unreachable() __builtin_unreachable() ++ ++/* Mark a function definition as prohibited from being cloned. */ ++#define __noclone __attribute__((__noclone__, __optimize__("no-tracer"))) ++ ++#endif /* GCC_VERSION >= 40500 */ ++ ++#if GCC_VERSION >= 40600 ++/* ++ * When used with Link Time Optimization, gcc can optimize away C functions or ++ * variables which are referenced only from assembly code. __visible tells the ++ * optimizer that something else uses this function or variable, thus preventing ++ * this. ++ */ ++#define __visible __attribute__((externally_visible)) ++#endif ++ ++ ++#if GCC_VERSION >= 40900 && !defined(__CHECKER__) ++/* ++ * __assume_aligned(n, k): Tell the optimizer that the returned ++ * pointer can be assumed to be k modulo n. The second argument is ++ * optional (default 0), so we use a variadic macro to make the ++ * shorthand. ++ * ++ * Beware: Do not apply this to functions which may return ++ * ERR_PTRs. Also, it is probably unwise to apply it to functions ++ * returning extra information in the low bits (but in that case the ++ * compiler should see some alignment anyway, when the return value is ++ * massaged by 'flags = ptr & 3; ptr &= ~3;'). ++ */ ++#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) ++#endif ++ ++/* ++ * GCC 'asm goto' miscompiles certain code sequences: ++ * ++ * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 ++ * ++ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. ++ * ++ * (asm goto is automatically volatile - the naming reflects this.) ++ */ ++#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) ++ ++#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP ++#if GCC_VERSION >= 40400 ++#define __HAVE_BUILTIN_BSWAP32__ ++#define __HAVE_BUILTIN_BSWAP64__ ++#endif ++#if GCC_VERSION >= 40800 ++#define __HAVE_BUILTIN_BSWAP16__ ++#endif ++#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ ++ ++#if GCC_VERSION >= 50000 ++#define KASAN_ABI_VERSION 4 ++#elif GCC_VERSION >= 40902 ++#define KASAN_ABI_VERSION 3 ++#endif ++ ++#if GCC_VERSION >= 40902 ++/* ++ * Tell the compiler that address safety instrumentation (KASAN) ++ * should not be applied to that function. ++ * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 ++ */ ++#define __no_sanitize_address __attribute__((no_sanitize_address)) ++#endif ++ ++#endif /* gcc version >= 40000 specific checks */ ++ ++#if !defined(__noclone) ++#define __noclone /* not needed */ ++#endif ++ ++#if !defined(__no_sanitize_address) ++#define __no_sanitize_address ++#endif ++ ++/* ++ * A trick to suppress uninitialized variable warning without generating any ++ * code ++ */ ++#define uninitialized_var(x) x = x -- 2.25.1