================
@@ -4022,8 +4169,36 @@ LValue CodeGenFunction::EmitArraySubscriptExpr(const
ArraySubscriptExpr *E,
ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true);
else
ArrayLV = EmitLValue(Array);
+
auto *Idx = EmitIdxAfterBase(/*Promote*/true);
+ if (SanOpts.has(SanitizerKind::ArrayBounds)) {
----------------
bwendling wrote:
I have checks in place to make sure that I can find the correct enclosing type.
For instance, if I have something like:
```
struct B {
int count;
int arr[] __counted_by(count);
};
struct A {
int count;
struct B *b;
};
```
when looking at `someA->b->arr[idx]`, it only cares about looking at the
`count` in `struct B`. The `count` in `struct A` won't be seen. This is because
we're looking for the most-enclosing struct of `arr`, which is `struct B`. Now
if I have something like:
```
struct A {
int count;
struct B {
int count;
int arr[] __counted_by(count);
} *ptr;
};
```
This could get hairy, because it might not see the `count` in `struct B`. BUT
if it's not a pointer:
```
struct A {
int count;
struct B {
int count;
int arr[] __counted_by(count);
} z;
};
```
Then I *do* want it to reference the `count` in `struct A`. Hilarious, I know!
:-) The "pointer" example should work exactly as if `struct B` was defined
outside of `struct A`. I'll need to make sure to document that very carefully.
As for other `-fbounds-safety` checks, I haven't seen any that do quite what
we're doing here. When I looked through the attributes, few of them seemed to
reference other fields within structures, or even external variables. (I know
some exist, but they're not quite the same as what we're doing here.) Then
again, I may quite well have not noticed one of the bounds safety code paths.
https://github.com/llvm/llvm-project/pull/73730
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