[PATCH 1/2] fix clang -Wconstant-conversion with bit fields
clang incorrectly reports a constant conversion warning (implicit
truncation to bit field) when using the flag = ~FLAG form, because
~FLAG needs to be truncated.
Convert this form to flag = flag ~FLAG fixes the issue as
the right operand now fits into the bit field.
Signed-off-by: Antoine Pelisse apeli...@gmail.com
---
I'm sorry about this fix, it really seems bad, yet it's one step closer
to warning-free clang compilation.
It seems quite clear to me that it's a bug in clang.
bisect.c | 2 +-
builtin/checkout.c | 2 +-
builtin/reflog.c | 4 ++--
commit.c | 4 ++--
revision.c | 8
upload-pack.c | 4 ++--
6 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/bisect.c b/bisect.c
index bd1b7b5..34ac01d 100644
--- a/bisect.c
+++ b/bisect.c
@@ -63,7 +63,7 @@ static void clear_distance(struct commit_list *list)
{
while (list) {
struct commit *commit = list-item;
- commit-object.flags = ~COUNTED;
+ commit-object.flags = commit-object.flags ~COUNTED;
list = list-next;
}
}
diff --git a/builtin/checkout.c b/builtin/checkout.c
index a9c1b5a..2c83234 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -717,7 +717,7 @@ static void orphaned_commit_warning(struct commit *old,
struct commit *new)
init_revisions(revs, NULL);
setup_revisions(0, NULL, revs, NULL);
- object-flags = ~UNINTERESTING;
+ object-flags = object-flags ~UNINTERESTING;
add_pending_object(revs, object, sha1_to_hex(object-sha1));
for_each_ref(add_pending_uninteresting_ref, revs);
diff --git a/builtin/reflog.c b/builtin/reflog.c
index b3c9e27..3079c81 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -170,7 +170,7 @@ static int commit_is_complete(struct commit *commit)
}
/* clear flags from the objects we traversed */
for (i = 0; i found.nr; i++)
- found.objects[i].item-flags = ~STUDYING;
+ found.objects[i].item-flags = found.objects[i].item-flags
~STUDYING;
if (is_incomplete)
commit-object.flags |= INCOMPLETE;
else {
@@ -229,7 +229,7 @@ static void mark_reachable(struct expire_reflog_cb *cb)
struct commit_list *leftover = NULL;
for (pending = cb-mark_list; pending; pending = pending-next)
- pending-item-object.flags = ~REACHABLE;
+ pending-item-object.flags = pending-item-object.flags
~REACHABLE;
pending = cb-mark_list;
while (pending) {
diff --git a/commit.c b/commit.c
index e8eb0ae..800779d 100644
--- a/commit.c
+++ b/commit.c
@@ -883,7 +883,7 @@ struct commit_list *reduce_heads(struct commit_list *heads)
/* Uniquify */
for (p = heads; p; p = p-next)
- p-item-object.flags = ~STALE;
+ p-item-object.flags = p-item-object.flags ~STALE;
for (p = heads, num_head = 0; p; p = p-next) {
if (p-item-object.flags STALE)
continue;
@@ -894,7 +894,7 @@ struct commit_list *reduce_heads(struct commit_list *heads)
for (p = heads, i = 0; p; p = p-next) {
if (p-item-object.flags STALE) {
array[i++] = p-item;
- p-item-object.flags = ~STALE;
+ p-item-object.flags = p-item-object.flags ~STALE;
}
}
num_head = remove_redundant(array, num_head);
diff --git a/revision.c b/revision.c
index d7562ee..ed1c16d 100644
--- a/revision.c
+++ b/revision.c
@@ -787,9 +787,9 @@ static void limit_to_ancestry(struct commit_list *bottom,
struct commit_list *li
/* We are done with the TMP_MARK */
for (p = list; p; p = p-next)
- p-item-object.flags = ~TMP_MARK;
+ p-item-object.flags = p-item-object.flags ~TMP_MARK;
for (p = bottom; p; p = p-next)
- p-item-object.flags = ~TMP_MARK;
+ p-item-object.flags = p-item-object.flags ~TMP_MARK;
free_commit_list(rlist);
}
@@ -1948,7 +1948,7 @@ static int remove_duplicate_parents(struct commit *commit)
/* count them while clearing the temporary mark */
surviving_parents = 0;
for (p = commit-parents; p; p = p-next) {
- p-item-object.flags = ~TMP_MARK;
+ p-item-object.flags = p-item-object.flags ~TMP_MARK;
surviving_parents++;
}
return surviving_parents;
@@ -2378,7 +2378,7 @@ static struct commit *get_revision_1(struct rev_info
*revs)
if (revs-reflog_info) {
fake_reflog_parent(revs-reflog_info, commit);
- commit-object.flags = ~(ADDED | SEEN | SHOWN);
+ commit-object.flags = commit-object.flags ~(ADDED |
SEEN | SHOWN);
}
/*
diff --git a/upload-pack.c b/upload-pack.c
index 7c05b15..74d8f0e 100644
---
Re: [PATCH 1/2] fix clang -Wconstant-conversion with bit fields
On Wed, Jan 16, 2013 at 11:47:22PM +0100, Antoine Pelisse wrote: clang incorrectly reports a constant conversion warning (implicit truncation to bit field) when using the flag = ~FLAG form, because ~FLAG needs to be truncated. Convert this form to flag = flag ~FLAG fixes the issue as the right operand now fits into the bit field. Signed-off-by: Antoine Pelisse apeli...@gmail.com --- I'm sorry about this fix, it really seems bad, yet it's one step closer to warning-free clang compilation. It seems quite clear to me that it's a bug in clang. Which version of clang did you see this with? I don't get these warnings with clang 3.2. John -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/2] fix clang -Wconstant-conversion with bit fields
On Thu, Jan 17, 2013 at 12:08 AM, John Keeping j...@keeping.me.uk wrote: On Wed, Jan 16, 2013 at 11:47:22PM +0100, Antoine Pelisse wrote: clang incorrectly reports a constant conversion warning (implicit truncation to bit field) when using the flag = ~FLAG form, because ~FLAG needs to be truncated. Which version of clang did you see this with? I don't get these warnings with clang 3.2. Ubuntu clang version 3.0-6ubuntu3 (tags/RELEASE_30/final) (based on LLVM 3.0) It's good to know it's been fixed ! -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/2] fix clang -Wconstant-conversion with bit fields
So I guess we should drop this patch, it's probably not worth it, especially if it's been fixed already by clang. On Thu, Jan 17, 2013 at 12:09 AM, Antoine Pelisse apeli...@gmail.com wrote: On Thu, Jan 17, 2013 at 12:08 AM, John Keeping j...@keeping.me.uk wrote: On Wed, Jan 16, 2013 at 11:47:22PM +0100, Antoine Pelisse wrote: clang incorrectly reports a constant conversion warning (implicit truncation to bit field) when using the flag = ~FLAG form, because ~FLAG needs to be truncated. Which version of clang did you see this with? I don't get these warnings with clang 3.2. Ubuntu clang version 3.0-6ubuntu3 (tags/RELEASE_30/final) (based on LLVM 3.0) It's good to know it's been fixed ! -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 1/2] fix clang -Wconstant-conversion with bit fields
Antoine Pelisse apeli...@gmail.com writes:
clang incorrectly reports a constant conversion warning (implicit
truncation to bit field) when using the flag = ~FLAG form, because
~FLAG needs to be truncated.
Convert this form to flag = flag ~FLAG fixes the issue as
the right operand now fits into the bit field.
If the clang incorrectly reports is already recognised by clang
folks as a bug to be fixed in clang, I'd rather not to take this
patch.
I do not think it is reasonable to expect people to remember that
they have to write flags = ~TO_DROP in a longhand whenever they
are adding new code that needs to do bit-fields, so even if this
patch makes clang silent for the _current_ code, it will not stay
that way. Something like
#define FLIP_BIT_CLR(fld,bit) do { \
typeof(fld) *x = (fld); \
*x = *x (~(bit)); \
} while (0)
may be more palapable but not by a large margin.
Yuck.
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Re: [PATCH 1/2] fix clang -Wconstant-conversion with bit fields
Junio C Hamano gits...@pobox.com writes:
Antoine Pelisse apeli...@gmail.com writes:
clang incorrectly reports a constant conversion warning (implicit
truncation to bit field) when using the flag = ~FLAG form, because
~FLAG needs to be truncated.
Convert this form to flag = flag ~FLAG fixes the issue as
the right operand now fits into the bit field.
If the clang incorrectly reports is already recognised by clang
folks as a bug to be fixed in clang, I'd rather not to take this
patch.
I do not think it is reasonable to expect people to remember that
they have to write flags = ~TO_DROP in a longhand whenever they
are adding new code that needs to do bit-fields, so even if this
patch makes clang silent for the _current_ code, it will not stay
that way. Something like
#define FLIP_BIT_CLR(fld,bit) do { \
typeof(fld) *x = (fld); \
*x = *x (~(bit)); \
} while (0)
may be more palapable but not by a large margin.
Yuck.
Double yuck. I meant palatable.
In any case, I see somebody reports that more recent clang does not
have this bug in the near-by message, so let's forget about this
issue.
Thanks.
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