================
@@ -206,12 +206,14 @@ llvm::MDNode *CodeGenTBAA::getTypeInfoHelper(const Type
*Ty) {
if (!CodeGenOpts.PointerTBAA)
return AnyPtr;
// Compute the depth of the pointer and generate a tag of the form
"p<depth>
- // <base type tag>".
+ // <base type tag>". Look through pointer and array types to determine the
+ // base type.
----------------
rjmccall wrote:
Suggestion as a replacement for the comment:
```
// C++ [basic.lval]p11 permits objects to accessed through an l-value
// of similar type. Two types are similar under C++ [conv.qual]p2
// if the decomposition of the types into pointers, member pointers,
// and arrays has the same structure when ignoring cv-qualifiers at
// each level of the decomposition. Meanwhile, C makes T(*)[] and
// T(*)[N] compatible, which would really complicate any attempt to
// distinguish pointers to arrays by their bounds. It's simpler, and
// much easier to explain to users, to simply treat all pointers to
// arrays as pointers to their element type for aliasing purposes.
// So when creating a TBAA tag for a pointer type, we recursively
// ignore both qualifiers and array types when decomposing
// the pointee type. The only meaningful remaining structure is the
// number of pointer types we encountered along the way, so we
// just produce the tag "p<depth> <base type tag>". If we do find a
// member pointer type, for now we just conservatively bail out
// with AnyPtr (below) rather than trying to create a tag that
// honors the similar-type rules while still distinguishing different
// kinds of member pointer.
```
https://github.com/llvm/llvm-project/pull/116991
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
