From f29831828441318c7916ae28e6e16e4a1c4a6795 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 18 Jan 2017 22:02:53 +0200 Subject: compiler: drop ; after BUILD_BUG_ON All users include the trailing ; anyway, let's require that - it seems cleaner. Signed-off-by: Michael S. Tsirkin Reviewed-by: Eric Blake Reviewed-by: Markus Armbruster --- include/qemu/compiler.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/qemu/compiler.h') diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 157698bfa9..75120826c1 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -86,7 +86,8 @@ #define type_check(t1,t2) ((t1*)0 - (t2*)0) #define QEMU_BUILD_BUG_ON(x) \ - typedef char glue(qemu_build_bug_on__,__LINE__)[(x)?-1:1] __attribute__((unused)); + typedef char glue(qemu_build_bug_on__, __LINE__)[(x) ? -1 : 1] \ + __attribute__((unused)) #if defined __GNUC__ # if !QEMU_GNUC_PREREQ(4, 4) -- cgit 1.4.1 From 60abf0a5e05134187e274ce5f32524ccf0cae1a6 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Tue, 31 Jan 2017 16:29:51 +0200 Subject: QEMU_BUILD_BUG_ON: use __COUNTER__ Some headers use QEMU_BUILD_BUG_ON. This causes a problem if the C file including that header happens to have QEMU_BUILD_BUG_ON at the same line number. Fix using a widely available extension: __COUNTER__. If unavailable, provide a stub. Signed-off-by: Michael S. Tsirkin Reviewed-by: Markus Armbruster Reviewed-by: Eric Blake --- include/qemu/compiler.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include/qemu/compiler.h') diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 75120826c1..77b9ce3979 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -85,9 +85,13 @@ #define typeof_field(type, field) typeof(((type *)0)->field) #define type_check(t1,t2) ((t1*)0 - (t2*)0) +#ifdef __COUNTER__ #define QEMU_BUILD_BUG_ON(x) \ - typedef char glue(qemu_build_bug_on__, __LINE__)[(x) ? -1 : 1] \ + typedef char glue(qemu_build_bug_on__, __COUNTER__)[(x) ? -1 : 1] \ __attribute__((unused)) +#else +#define QEMU_BUILD_BUG_ON(x) +#endif #if defined __GNUC__ # if !QEMU_GNUC_PREREQ(4, 4) -- cgit 1.4.1 From f291887e8eef5d37d31484638f6e62401b4b99a2 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 19 Jan 2017 22:56:14 +0200 Subject: compiler: rework BUG_ON using a struct There are theoretical concerns that some compilers might not trigger build failures on attempts to define an array of size (x ? -1 : 1) where x is a variable and make it a variable sized array instead. Let rewrite using a struct with a negative bit field size instead as there are no dynamic bit field sizes. This is similar to what Linux does. Signed-off-by: Michael S. Tsirkin Reviewed-by: Eric Blake Reviewed-by: Markus Armbruster --- include/qemu/compiler.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'include/qemu/compiler.h') diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 77b9ce3979..057639af43 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -85,10 +85,14 @@ #define typeof_field(type, field) typeof(((type *)0)->field) #define type_check(t1,t2) ((t1*)0 - (t2*)0) +#define QEMU_BUILD_BUG_ON_STRUCT(x) \ + struct { \ + int:(x) ? -1 : 1; \ + } + #ifdef __COUNTER__ -#define QEMU_BUILD_BUG_ON(x) \ - typedef char glue(qemu_build_bug_on__, __COUNTER__)[(x) ? -1 : 1] \ - __attribute__((unused)) +#define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \ + glue(qemu_build_bug_on__, __COUNTER__) __attribute__((unused)) #else #define QEMU_BUILD_BUG_ON(x) #endif -- cgit 1.4.1 From d757573e69f2ef58a4a7b41f6c55d65fa1e1c5c2 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 18 Jan 2017 22:05:15 +0200 Subject: compiler: expression version of QEMU_BUILD_BUG_ON QEMU_BUILD_BUG_ON uses a typedef in order to be safe to use outside functions, but sometimes it's useful to have a version that can be used within an expression. Following what Linux does, introduce QEMU_BUILD_BUG_ON_ZERO that return zero after checking condition at build time. Signed-off-by: Michael S. Tsirkin Reviewed-by: Eric Blake Reviewed-by: Markus Armbruster --- include/qemu/compiler.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/qemu/compiler.h') diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 057639af43..e0ce9ffb28 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -97,6 +97,9 @@ #define QEMU_BUILD_BUG_ON(x) #endif +#define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \ + sizeof(QEMU_BUILD_BUG_ON_STRUCT(x))) + #if defined __GNUC__ # if !QEMU_GNUC_PREREQ(4, 4) /* gcc versions before 4.4.x don't support gnu_printf, so use printf. */ -- cgit 1.4.1