[NFC][clang-tidy] Disable test for bugprone-unsafe-functions for PlayStation

As discussed in [D91000](http://reviews.llvm.org/D91000) with @dyung, the
PlayStation-specific targets are using some custom standard library for
which the current written tests are not appropriate. Even though the
test code defines the `__STDC_LIB_EXT1__` and `__STDC_WANT_LIB_EXT1__`
macros and expected *Annex K.* support, the actual Clang
parser/preprocessor will report these macros as not existing, and thus
fail the tests.

The check reports the **non**-Annex K. functions as suggestions, such as
`fgets()` instead of `gets_s()` to replace `gets()`, so some safe
library suggestions are still there.

This patch is primarily done to unblock the relevant buildbot
[`llvm-clang-x86_64-sie-ubuntu-fast`](http://lab.llvm.org/buildbot/#/builders/139).

This commit partially reverts ed740e7,
as the changes to the "caching logic" was not fixing anything.

Author: whisperity

clang-tools-extra/clang-tidy/bugprone/UnsafeFunctionsCheck.cpp

@@ -226,6 +226,10 @@ void UnsafeFunctionsCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP,
     Preprocessor * /*ModuleExpanderPP*/) {
   this->PP = PP;
+}
+
+void UnsafeFunctionsCheck::onEndOfTranslationUnit() {
+  this->PP = nullptr;
   IsAnnexKAvailable.reset();
 }
 

clang-tools-extra/clang-tidy/bugprone/UnsafeFunctionsCheck.h

@@ -32,6 +32,7 @@ class UnsafeFunctionsCheck : public ClangTidyCheck {
 
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
+  void onEndOfTranslationUnit() override;
 
 private:
   /// If true, additional functions from widely used API-s (such as POSIX) are

clang-tools-extra/test/clang-tidy/checkers/bugprone/unsafe-functions.c

@@ -1,3 +1,10 @@
+// This test fails on "x86_64-sie" buildbot and "x86_64-scei-ps4" target.
+// According to @dyung, something related to the kind of standard library
+// availability is causing the failure. Even though we explicitly define
+// the relevant macros the check is hunting for in the invocation, the real
+// parsing and preprocessor state will not have that case.
+// UNSUPPORTED: target={{.*-(ps4|ps5)}}
+//
 // RUN: %check_clang_tidy -check-suffix=WITH-ANNEX-K            %s bugprone-unsafe-functions %t -- -- -D__STDC_LIB_EXT1__=1 -D__STDC_WANT_LIB_EXT1__=1
 // RUN: %check_clang_tidy -check-suffix=WITHOUT-ANNEX-K         %s bugprone-unsafe-functions %t -- -- -U__STDC_LIB_EXT1__   -U__STDC_WANT_LIB_EXT1__
 // RUN: %check_clang_tidy -check-suffix=WITHOUT-ANNEX-K         %s bugprone-unsafe-functions %t -- -- -D__STDC_LIB_EXT1__=1 -U__STDC_WANT_LIB_EXT1__
@@ -16,8 +23,11 @@ size_t wcslen(const wchar_t *S);
 void f1(char *S) {
   gets(S);
   // CHECK-MESSAGES-WITH-ANNEX-K:           :[[@LINE-1]]:3: warning: function 'gets' is insecure, was deprecated and removed in C11 and C++14; 'gets_s' should be used instead [bugprone-unsafe-functions]
-  // CHECK-MESSAGES-WITH-ANNEX-K-CERT-ONLY: :[[@LINE-2]]:3: warning: function 'gets' is insecure, was deprecated and removed in C11 and C++14; 'gets_s' should be used instead
-  // CHECK-MESSAGES-WITHOUT-ANNEX-K:        :[[@LINE-3]]:3: warning: function 'gets' is insecure, was deprecated and removed in C11 and C++14; 'fgets' should be used instead
+  // FIXME(?): On target=x86_64-scie-ps4, the above warning in the
+  // "-WITH-ANNEX-K" case will still report the suggestion to use 'fgets'
+  // instead of the expected 'get_s', as if "Annex K" was not available.
+  // CHECK-MESSAGES-WITH-ANNEX-K-CERT-ONLY: :[[@LINE-5]]:3: warning: function 'gets' is insecure, was deprecated and removed in C11 and C++14; 'gets_s' should be used instead
+  // CHECK-MESSAGES-WITHOUT-ANNEX-K:        :[[@LINE-6]]:3: warning: function 'gets' is insecure, was deprecated and removed in C11 and C++14; 'fgets' should be used instead
 
   strlen(S);
   // CHECK-MESSAGES-WITH-ANNEX-K:           :[[@LINE-1]]:3: warning: function 'strlen' is not bounds-checking; 'strnlen_s' should be used instead