threads / patch / 39707

patchFix definition of ARRAY_SIZE for non-gcc builds

Subject: [PATCH] Fix definition of ARRAY_SIZE for non-gcc builds

## tl;dr

3 messages between Jun 24, 2015 and Jun 24, 2015. Diffs are folded; open one to read it.

replies: 2people: 1as markdown or json

Charles Bailey· Jun 24, 2015, 07:44 UTC · lore

From: Charles Bailey <cbailey32@bloomberg.net>

The improved ARRAY_SIZE macro uses BARF_UNLESS_AN_ARRAY which is expands to a valid check for recent gcc versions and to 0 for older gcc versions but is not defined on non-gcc builds.

Non-gcc builds need this macro to expand to 0 as well. The current outer test (defined(__GNUC__) && (__GNUC__)) is a strictly weaker condition than the inner test (GIT_GNUC_PREREQ(3, 1)) so we can omit the outer test and cause the BARF_UNLESS_AN_ARRAY macro to be defined correctly on non-gcc builds as well as gcc builds with older versions.

Signed-off-by: Charles Bailey <cbailey32@bloomberg.net>
---

This fixes a build regression introduced in v2.4.4 so this patch is based off that tag.

 git-compat-util.h | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

Show changes to git-compat-util.h +3 −5

diff --git a/git-compat-util.h b/git-compat-util.h
index b45c75f..8c2b7aa 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -58,15 +58,13 @@
 #define BUILD_ASSERT_OR_ZERO(cond) \
 	(sizeof(char [1 - 2*!(cond)]) - 1)
 
-#if defined(__GNUC__) && (__GNUC__ >= 3)
-# if GIT_GNUC_PREREQ(3, 1)
+#if GIT_GNUC_PREREQ(3, 1)
  /* &arr[0] degrades to a pointer: a different type from an array */
 # define BARF_UNLESS_AN_ARRAY(arr)						\
 	BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
 							   __typeof__(&(arr)[0])))
-# else
-#  define BARF_UNLESS_AN_ARRAY(arr) 0
-# endif
+#else
+# define BARF_UNLESS_AN_ARRAY(arr) 0
 #endif
 /*
  * ARRAY_SIZE - get the number of elements in a visible array

-- 
2.4.0.53.g8440f74

Charles Bailey· Jun 24, 2015, 22:12 UTC · re: Charles Bailey · lore

[PATCH v2] Fix definition of ARRAY_SIZE for non-gcc builds

From: Charles Bailey <cbailey32@bloomberg.net>

The improved ARRAY_SIZE macro uses BARF_UNLESS_AN_ARRAY which is expands to a valid check for recent gcc versions and to 0 for older gcc versions but is not defined on non-gcc builds.

Non-gcc builds need this macro to expand to 0 as well. The current outer test (defined(__GNUC__) && (__GNUC__ >= 3)) is a strictly weaker condition than the inner test (GIT_GNUC_PREREQ(3, 1)) so we can omit the outer test and cause the BARF_UNLESS_AN_ARRAY macro to be defined correctly on non-gcc builds as well as gcc builds with older versions.

Signed-off-by: Charles Bailey <cbailey32@bloomberg.net>
---

This resend fixes a copy and paste error in the outer test in the commit message. The patch remains the same.

This fixes a build regression introduced in v2.4.4 so this patch is based off maint.

 git-compat-util.h | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

Show changes to git-compat-util.h +3 −5

diff --git a/git-compat-util.h b/git-compat-util.h
index b45c75f..8c2b7aa 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -58,15 +58,13 @@
 #define BUILD_ASSERT_OR_ZERO(cond) \
 	(sizeof(char [1 - 2*!(cond)]) - 1)
 
-#if defined(__GNUC__) && (__GNUC__ >= 3)
-# if GIT_GNUC_PREREQ(3, 1)
+#if GIT_GNUC_PREREQ(3, 1)
  /* &arr[0] degrades to a pointer: a different type from an array */
 # define BARF_UNLESS_AN_ARRAY(arr)						\
 	BUILD_ASSERT_OR_ZERO(!__builtin_types_compatible_p(__typeof__(arr), \
 							   __typeof__(&(arr)[0])))
-# else
-#  define BARF_UNLESS_AN_ARRAY(arr) 0
-# endif
+#else
+# define BARF_UNLESS_AN_ARRAY(arr) 0
 #endif
 /*
  * ARRAY_SIZE - get the number of elements in a visible array

-- 
2.4.0.53.g8440f74

Charles Bailey· Jun 24, 2015, 22:19 UTC · re: Charles Bailey · lore

Re: [PATCH v2] Fix definition of ARRAY_SIZE for non-gcc builds

On Wed, Jun 24, 2015 at 11:12:07PM +0100, Charles Bailey wrote:

Show 5 quoted lines

> From: Charles Bailey <cbailey32@bloomberg.net>
> 
> The improved ARRAY_SIZE macro uses BARF_UNLESS_AN_ARRAY which is expands
> to a valid check for recent gcc versions and to 0 for older gcc
> versions but is not defined on non-gcc builds.

 
Actually hitting send is a sure fire way to get me spot other errors:
s/which is expands/which expands/