[clang] [llvm] Make sanitizer special case list slash-agnostic (PR #149886)

[Vitaly Buka via llvm-commits]

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@@ -196,6 +196,23 @@ tool-specific docs.
     [{cfi-vcall,cfi-icall}]
     fun:*BadCfiCall
 
+
+.. note::
+
+  By default, ``src`` and ``mainfile`` are matched against the filename as seen
+  by LLVM. On Windows, this might involve a mix of forward and backslashes as
+  file separators, and writing patterns to match both variants can be
+  inconvenient.
+  
+  If the special case list file begins with ``#!canonical-paths``, then paths
+  will be canonicalized before patterns are matched against them. This involves
+  stripping any leading dots and slashes, and (on Windows only) converting all
+  backslashes to forward slashes.
+
+  If the file uses both ``#!special-case-list-v1`` and ``#!canonical-paths``,
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vitalybuka wrote:

Let's just do '#!special-case-list-v2' for current behavior, 
and we will garbage collect v1, v2 in future.

#!special-case-list-v1 is just for transition, maybe it's already time to remove it.

If we do opt-in with #!canonical-paths, then we just delaying transition for later and it does not make it easier.

https://github.com/llvm/llvm-project/pull/149886