[analyzer] StdLibraryFunctionsChecker: Add overload for adding the same summary for different names

[martong]

Summary

Adding a convenience function for makeing it easier to add the same summary for functions with different names.
E.g. we are going to use the same summary for

char * strchr(const char *cs, int c);
char * strrchr(const char * str, int character);

[balazske]

clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp

672

Theoretically it is possible to have a multiple names-multiple summaries case (multiple function names that have the same overloads)?

[xazax.hun]

I'd prefer to have this functionality committed together its first actual use with tests.

I also agree with @balazske, we should diagnose the cases when we have multiple summaries for the same function.

[martong]

In D79425#2022245, @xazax.hun wrote:

I'd prefer to have this functionality committed together its first actual use with tests.

Okay, at the current state we add a summary individually for each name, that makes it easier to modify a summary for each function without effecting other functions.

I also agree with @balazske, we should diagnose the cases when we have multiple summaries for the same function.

We already handle these cases with an assertion:

auto Res = Map.insert({FD->getCanonicalDecl(), S});
assert(Res.second && "Function already has a summary set!");
(void)Res;

clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp

672

I think yes, that would be possible.

[martong]

At the current state we add a summary individually for each name, that makes it easier to modify a summary for each function without effecting other functions. I'll add this functionality in the future when a real use cases comes up, if that really comes up.

clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp

void operator()(StringRef Name, const Summary &S) {
         }
       }
     }
     // Add several summaries for the given name.
     void operator()(StringRef Name, const std::vector<Summary> &Summaries) {
       for (const Summary &S : Summaries)
         operator()(Name, S);
     }
+    // Add the same summary for different names.
+    void operator()(std::vector<StringRef> Names, Summary S) {
+      for (StringRef Name : Names)
+        operator()(Name, S);
+    }
   } addToFunctionSummaryMap(ACtx, FunctionSummaryMap);
 
   // We are finally ready to define specifications for all supported functions.
   //
   // The signature needs to have the correct number of arguments.
   // However, we insert `Irrelevant' when the type is insignificant.
   //
   // Argument ranges should always cover all variants. If return value