[clang] Warning Libc functions (PR #101583)

[Artem Dergachev via cfe-commits]

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@@ -443,6 +448,368 @@ AST_MATCHER(ArraySubscriptExpr, isSafeArraySubscript) {
   return false;
 }
 
+namespace libc_fun_disjoint_inner_matchers {
+// `libc_fun_disjoint_inner_matchers` covers a set of matchers that match
+// disjoint node sets.   They all take a `CoreName`, which is the substring of a
+// function name after `ignoreLibcPrefixAndSuffix`.  They are suppose to be used
+// as an inner matcher of `ignoreLibcPrefixAndSuffix` to deal with different
+// libc function calls.
+
+// Matches a function call node such that
+//  1. It's name, after stripping off predefined prefix and suffix, is
+//     `CoreName`; and
+//  2. `CoreName` or `CoreName[str/wcs]` is one of the `PredefinedNames`, which
+//     is a set of libc function names.
+//
+//  Note: For predefined prefix and suffix, see `ignoreLibcPrefixAndSuffix`.
+//  And, the notation `CoreName[str/wcs]` means a new name obtained from replace
+//  string "wcs" with "str" in `CoreName`.
+//
+//  Also note, the set of predefined function names does not include `printf`
+//  functions, they are checked exclusively with other matchers below.
+//  Maintaining the invariant that all matchers under
+//  `libc_fun_disjoint_inner_matchers` are disjoint.
+AST_MATCHER_P(CallExpr, predefinedUnsafeLibcFunCall, StringRef, CoreName) {
+  static const std::set<StringRef> PredefinedNames{
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haoNoQ wrote:

We can't have nice things because of https://llvm.org/docs/CodingStandards.html#do-not-use-static-constructors - if we need this to store this as a set (and I think we do because of the sheer size of it), we have to store it as a raw pointer and lazy-initialize it on first use.

https://github.com/llvm/llvm-project/pull/101583