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

[Vitaly Buka via cfe-commits]

================
@@ -48,6 +49,59 @@ Example
   $ clang -fsanitize=address -fsanitize-ignorelist=ignorelist.txt foo.c ; ./a.out
   # No error report here.
 
+Usage with UndefinedBehaviorSanitizer
+=====================================
+
+The arithmetic overflow sanitizers ``unsigned-integer-overflow`` and
+``signed-integer-overflow`` as well as the implicit integer truncation
+sanitizers ``implicit-signed-integer-truncation`` and
+``implicit-unsigned-integer-truncation`` support the ability to adjust
+instrumentation based on type.
+
+.. code-block:: bash
+
+  $ cat foo.c
+  void foo() {
+    int a = 2147483647; // INT_MAX
+    ++a;                // Normally, an overflow with -fsanitize=signed-integer-overflow
+  }
+  $ cat ignorelist.txt
+  [signed-integer-overflow]
+  type:int
+  $ clang -fsanitize=signed-integer-overflow -fsanitize-ignorelist=ignorelist.txt foo.c ; ./a.out
+  # no signed-integer-overflow error
+
+For example, supplying the above ``ignorelist.txt`` to
+``-fsanitize-ignorelist=ignorelist.txt`` disables overflow sanitizer
+instrumentation for arithmetic operations containing values of type ``int``.
+
+The following SCL categories are supported: ``=no_sanitize`` and ``=sanitize``.
+The ``no_sanitize`` category is the default for any entry within an ignorelist
----------------
vitalybuka wrote:

Actually 'SpecialCaseList::inSectionBlame' supports linenumber
So we can make it work, with some refactoring, in future patches.

Maybe put comment here that order if undefined?

SpecialCaseList supports multiple files as input, comparing linenumber between them is not helpfull, should be a pair <> of numbers.

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