[PATCH 1/2] coccinelle: remove parentheses that become unnecessary

René Scharfe· Oct 1, 2017, 15:12 UTC · lore

Transformations that hide multiplications can end up with an pair of parentheses that is no longer needed. E.g. with a rule like this:

  @@
  expression E;
  @@
  - E * 2
  + double(E)

... we might get a patch like this:

  -	x = (a + b) * 2;
  +	x = double((a + b));

Add a pair of parentheses to the preimage side of such rules. Coccinelle will generate patches that remove them if they are present, and it will still match expressions that lack them.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 contrib/coccinelle/array.cocci | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Show changes to contrib/coccinelle/array.cocci +5 −5

diff --git a/contrib/coccinelle/array.cocci b/contrib/coccinelle/array.cocci
index c61d1ca8dc..01586821dc 100644
--- a/contrib/coccinelle/array.cocci
+++ b/contrib/coccinelle/array.cocci
@@ -4,7 +4,7 @@ T *dst;
 T *src;
 expression n;
 @@
-- memcpy(dst, src, n * sizeof(*dst));
+- memcpy(dst, src, (n) * sizeof(*dst));
 + COPY_ARRAY(dst, src, n);
 
 @@
@@ -13,7 +13,7 @@ T *dst;
 T *src;
 expression n;
 @@
-- memcpy(dst, src, n * sizeof(*src));
+- memcpy(dst, src, (n) * sizeof(*src));
 + COPY_ARRAY(dst, src, n);
 
 @@
@@ -22,7 +22,7 @@ T *dst;
 T *src;
 expression n;
 @@
-- memcpy(dst, src, n * sizeof(T));
+- memcpy(dst, src, (n) * sizeof(T));
 + COPY_ARRAY(dst, src, n);
 
 @@
@@ -47,7 +47,7 @@ type T;
 T *ptr;
 expression n;
 @@
-- ptr = xmalloc(n * sizeof(*ptr));
+- ptr = xmalloc((n) * sizeof(*ptr));
 + ALLOC_ARRAY(ptr, n);
 
 @@
@@ -55,5 +55,5 @@ type T;
 T *ptr;
 expression n;
 @@
-- ptr = xmalloc(n * sizeof(T));
+- ptr = xmalloc((n) * sizeof(T));
 + ALLOC_ARRAY(ptr, n);

-- 
2.14.2

René Scharfe· Oct 1, 2017, 15:14 UTC · re: René Scharfe · lore

[PATCH 2/2] run-command: use ALLOC_ARRAY

Use the macro ALLOC_ARRAY to allocate an array. This is shorter and eaasier, as it automatically infers the size of elements.

Patch generated with Coccinelle and contrib/coccinelle/array.cocci.

Signeg-off-by: Rene Scharfe <l.s.r@web.de>
---
 run-command.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Show changes to run-command.c +1 −1

diff --git a/run-command.c b/run-command.c
index b5e6eb37c0..014b2165b5 100644
--- a/run-command.c
+++ b/run-command.c
@@ -452,7 +452,7 @@ static char **prep_childenv(const char *const *deltaenv)
 	}
 
 	/* Create an array of 'char *' to be used as the childenv */
-	childenv = xmalloc((env.nr + 1) * sizeof(char *));
+	ALLOC_ARRAY(childenv, env.nr + 1);
 	for (i = 0; i < env.nr; i++)
 		childenv[i] = env.items[i].util;
 	childenv[env.nr] = NULL;

-- 
2.14.2

Stefan Beller· Oct 2, 2017, 19:20 UTC · re: René Scharfe · lore

Re: [PATCH 2/2] run-command: use ALLOC_ARRAY

On Sun, Oct 1, 2017 at 8:14 AM, René Scharfe <l.s.r@web.de> wrote:

> Use the macro ALLOC_ARRAY to allocate an array.  This is shorter and
> eaasier, as it automatically infers the size of elements.

easier

Thanks, Stefan

patch, 2 partscoccinelle: remove parentheses that become unnecessary