[PATCH] D140179: [WIP][-Wunsafe-buffer-usage] Add unsafe buffer checking opt-out pragmas

[Ziqing Luo via Phabricator via cfe-commits]

ziqingluo-90 added inline comments.


================
Comment at: clang/lib/Analysis/UnsafeBufferUsage.cpp:551-555
+        allOf(declStmt().bind("any_ds"), notInSafeBufferOptOut())
+        // We match all DREs regardless of whether they are in safe-buffer
+        // opt-out region. Because an unclaimed DRE 'd', regardless of where it is,
+        // should prevent a Fixable associated to the same variable as 'd'
+        // from being emitting.
----------------
NoQ wrote:
> ziqingluo-90 wrote:
> > NoQ wrote:
> > > I think we should match all DeclStmts as well, because otherwise we may be unable to find the variable to fix.
> > In case we are unable to find the variable to fix,  it means that the variable declaration is in an opt-out zone.  So we don't fix the variable anyway, right?
> > 
> > Or do you mean that a variable may still get fixed even if its declaration is in an opt-out zone?   I could imagine it is possible if the variable is involved in some assignments that we want to fix.
> > do you mean that a variable may still get fixed even if its declaration is in an opt-out zone?
> 
> Yes I think that's the case. We do have tests about this right?:
> ```lang=c++
> #pragma clang unsafe_buffer_usage begin
>   ...
>   int *p3 = new int[10]; // expected-warning{{'p3' is an unsafe pointer used for buffer access}}
> 
> #pragma clang unsafe_buffer_usage end
>   ...
>   p3[5]; //expected-note{{used in buffer access here}}
> ```
> And I think it's safe to assume that every time we emit a warning, we also want to emit a fixit.
> 
> If only we had any fixits implemented, this code would have been much easier to refactor because we'd have some actual tests covering it 🤔
sorry I didn't think it through when I reply the comments.  You are right.
Fixables and variable declarations should be irrelevant to opt-out regions.

I'll rebase this patch w.r.t. https://reviews.llvm.org/D139737 so that we will have tests covering it.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D140179/new/

https://reviews.llvm.org/D140179