[clang] [Clang] Implement labelled type filtering for overflow/truncation sanitizers w/ SSCLs (PR #107332)

[Justin Stitt via cfe-commits]

================
@@ -831,6 +831,28 @@ ASTContext::getCanonicalTemplateTemplateParmDecl(
   return CanonTTP;
 }
 
+/// Check if a type can have its sanitizer instrumentation elided.
+/// Determine this by its presence in a SCL alongside its specified categories.
+/// For example:
+/// ignorelist.txt>
+/// [{unsigned-integer-overflow,signed-integer-overflow}]
+/// type:*=no_sanitize
+/// type:size_t=sanitize
+/// <ignorelist.txt
+/// Supplying the above ignorelist.txt will disable overflow sanitizer
+/// instrumentation for all types except "size_t".
+bool ASTContext::isTypeIgnoredBySanitizer(const SanitizerMask &Mask,
+                                          const QualType &Ty) const {
+  bool sanitizeType =
+      NoSanitizeL->containsType(Mask, Ty.getAsString(), "sanitize");
+
+  bool noSanitizeType =
----------------
JustinStitt wrote:

> Can you add a test to control that? with current patch canonical works.

For the purposes of the overflow sanitizers, we want to support both canonical and typedef types.


e.g.:
```
type:int=sanitize
... or ...
type:my_int=sanitize
```

The current tests sort of already test for both canonical and typedef types implicitly. Do we think a more explicit test is required?

https://github.com/llvm/llvm-project/pull/107332