Anyway, you may also want to consider cases where the result of the function is
assigned to a variable that is unused.
I would like to extend the suggested example. But I see the next challenges
besides variable assignment chains.
How can the following use cases be efficiently specified for the semantic patch
language?
A function return value or a corresponding variable is not used in ...
1. ... a conditional expression.
2. ... a function call parameter.
Would it be needed to filter the source code with positive checks and apply a
negation in the last analysis step like in the following approach?
@is_assigned@
identifier x, y;
@@
y = x(...)
@is_checked1@
identifier is_assigned.y;
@@
(
if (<+... y ...+>)
|
(<+... y ...+>) ? ... : ...
)
@is_checked2@
identifier f;
@@
(
if (<+... f(...) ...+>)
|
(<+... f(...) ...+>) ? ... : ...
)
@is_forwarded@
identifier c, f, assign.y;
@@
(
c(..., y, ...)
|
f(...)
{<+...
c(..., y, ...);
...+>}
)
@depends on !is_void && !(is_checked1 && is_checked2 && is_forwarded)@
identifier r.f, g;
@@
g(...)
{<+...
* f(...);
...+>}
Will it also be needed here to distinguish the used identifiers between names
for function and preprocessor macro calls?
Regards,
Markus
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