git/contrib/coccinelle/swap.cocci

@@
type T;
identifier tmp;
T a, b;
@@
- T tmp = a;
+ T tmp;
+ tmp = a;
  a = b;
  b = tmp;

@ swap @
type T;
T tmp, a, b;
@@
- tmp = a;
- a = b;
- b = tmp;
+ SWAP(a, b);

@ extends swap @
identifier unused;
@@
  {
  ...
- T unused;
  ... when != unused
  }
cocci rules: remove <id>'s from rules that don't need them The <id> in the <rulename> part of the coccinelle syntax[1] is for our purposes there to declares if we have inter-dependencies between different rules. But such <id>'s must be unique within a given semantic patch file. As we'll be processing a concatenated version of our rules in the subsequent commit let's remove these names. They weren't being used for the semantic patches themselves, and equated to a short comment about the rule. Both the filename and context of the rules makes it clear what they're doing, so we're not gaining anything from keeping these. Retaining them goes against recommendations that "contrib/coccinelle/README" will be making in the subsequent commit. This leaves only one named rule in our sources, where it's needed for a "<id> <-> <extends> <id>" relationship: $ git -P grep '^@ ' -- contrib/coccinelle/ contrib/coccinelle/swap.cocci:@ swap @ contrib/coccinelle/swap.cocci:@ extends swap @ 1. https://coccinelle.gitlabpages.inria.fr/website/docs/main_grammar.html Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> 2022-11-01 22:35:53 +00:00			`@@`
add SWAP macro Add a macro for exchanging the values of variables. It allows users to avoid repetition and takes care of the temporary variable for them. It also makes sure that the storage sizes of its two parameters are the same. Its memcpy(1) calls are optimized away by current compilers. Also add a conservative semantic patch for transforming only swaps of variables of the same type. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com> 2017-01-28 21:38:21 +00:00			`type T;`
			`identifier tmp;`
			`T a, b;`
			`@@`
			`- T tmp = a;`
			`+ T tmp;`
			`+ tmp = a;`
			`a = b;`
			`b = tmp;`

			`@ swap @`
			`type T;`
			`T tmp, a, b;`
			`@@`
			`- tmp = a;`
			`- a = b;`
			`- b = tmp;`
			`+ SWAP(a, b);`

			`@ extends swap @`
			`identifier unused;`
			`@@`
			`{`
			`...`
			`- T unused;`
			`... when != unused`
			`}`