Clang fails to diagnose:
```
void test() {
int j = 0;
for (int i = 0; i < 1000; i++)
j++;
return;
}
```
Reason: Missing support for UnaryOperator.
We should not warn with volatile variables... so add check for it.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D122271
For the following code,
void test() {
volatile int j = 0;
for (int i = 0; i < 1000; i++)
j += 1;
return;
}
If compiled with
clang -g -Wall -Werror -S -emit-llvm test.c
we will see the following error:
test.c:2:6: error: variable 'j' set but not used [-Werror,-Wunused-but-set-variable]
volatile int j = 0;
^
This is not quite right since 'j' is indeed used due to '+=' operator.
gcc doesn't emit error either in this case.
Also if we change 'j += 1' to 'j++', the warning will disappear
with latest clang.
Note that clang will issue the warning if the volatile declaration
involves only simple assignment (var = ...).
To fix the issue, in function MaybeDecrementCount(), if the
operator is a compound assignment (i.e., +=, -=, etc.) and the
variable is volatile, the count for RefsMinusAssignments will be
decremented, similar to 'j++' case.
Differential Revision: https://reviews.llvm.org/D121715
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the third batch of tests being updated (there are a significant
number of other tests left to be updated).
This applies to -Wunused-but-set-variable and
-Wunused-but-set-parameter.
This addresses bug 51865.
Differential Revision: https://reviews.llvm.org/D109862
These are intended to mimic warnings available in gcc.
-Wunused-but-set-variable is triggered in the case of a variable which
appears on the LHS of an assignment but not otherwise used.
For instance:
void f() {
int x;
x = 0;
}
-Wunused-but-set-parameter works similarly, but for function parameters
instead of variables.
In C++, they are triggered only for scalar types; otherwise, they are
triggered for all types. This is gcc's behavior.
-Wunused-but-set-parameter is controlled by -Wextra, while
-Wunused-but-set-variable is controlled by -Wunused. This is slightly
different from gcc's behavior, but seems most consistent with clang's
behavior for -Wunused-parameter and -Wunused-variable.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D100581
Dávid Bolvanský