[analyzer] Don't allow hidden checkers to emit diagnostics

Hidden checkers (those marked with Hidden in Checkers.td) are meant for
development purposes only, and are only displayed under
-analyzer-checker-help-developer, so users shouldn't see reports from them.

I moved StdLibraryFunctionsArg checker to the unix package from apiModeling as
it violated this rule. I believe this change doesn't deserve a different
revision because it is in alpha, and the name is so bad anyways I don't
immediately care where it is, because we'll have to revisit it soon enough.

Differential Revision: https://reviews.llvm.org/D81750

clang/include/clang/StaticAnalyzer/Checkers/Checkers.td

@@ -375,18 +375,6 @@ def TrustNonnullChecker : Checker<"TrustNonnull">,
 
 } // end "apiModeling"
 
-let ParentPackage = APIModelingAlpha in {
-
-def StdCLibraryFunctionArgsChecker : Checker<"StdCLibraryFunctionArgs">,
-  HelpText<"Check constraints of arguments of C standard library functions, "
-           "such as whether the parameter of isalpha is in the range [0, 255] "
-           "or is EOF.">,
-  Dependencies<[StdCLibraryFunctionsChecker]>,
-  WeakDependencies<[NonNullParamChecker]>,
-  Documentation<NotDocumented>;
-
-} // end "alpha.apiModeling"
-
 //===----------------------------------------------------------------------===//
 // Evaluate "builtin" functions.
 //===----------------------------------------------------------------------===//
@@ -545,6 +533,14 @@ def BlockInCriticalSectionChecker : Checker<"BlockInCriticalSection">,
   HelpText<"Check for calls to blocking functions inside a critical section">,
   Documentation<HasAlphaDocumentation>;
 
+def StdCLibraryFunctionArgsChecker : Checker<"StdCLibraryFunctionArgs">,
+  HelpText<"Check constraints of arguments of C standard library functions, "
+           "such as whether the parameter of isalpha is in the range [0, 255] "
+           "or is EOF.">,
+  Dependencies<[StdCLibraryFunctionsChecker]>,
+  WeakDependencies<[NonNullParamChecker]>,
+  Documentation<NotDocumented>;
+
 } // end "alpha.unix"
 
 //===----------------------------------------------------------------------===//

clang/lib/StaticAnalyzer/Core/BugReporter.cpp

@@ -2108,8 +2108,8 @@ void BuiltinBug::anchor() {}
 // Methods for BugReport and subclasses.
 //===----------------------------------------------------------------------===//
 
-static bool isDependency(const CheckerRegistryData &Registry,
-                         StringRef CheckerName) {
+LLVM_ATTRIBUTE_USED static bool
+isDependency(const CheckerRegistryData &Registry, StringRef CheckerName) {
   for (const std::pair<StringRef, StringRef> &Pair : Registry.Dependencies) {
     if (Pair.second == CheckerName)
       return true;
@@ -2117,6 +2117,17 @@ static bool isDependency(const CheckerRegistryData &Registry,
   return false;
 }
 
+LLVM_ATTRIBUTE_USED static bool isHidden(const CheckerRegistryData &Registry,
+                                         StringRef CheckerName) {
+  for (const CheckerInfo &Checker : Registry.Checkers) {
+    if (Checker.FullName == CheckerName)
+      return Checker.IsHidden;
+  }
+  llvm_unreachable(
+      "Checker name not found in CheckerRegistry -- did you retrieve it "
+      "correctly from CheckerManager::getCurrentCheckerName?");
+}
+
 PathSensitiveBugReport::PathSensitiveBugReport(
     const BugType &bt, StringRef shortDesc, StringRef desc,
     const ExplodedNode *errorNode, PathDiagnosticLocation LocationToUnique,
@@ -2132,6 +2143,16 @@ PathSensitiveBugReport::PathSensitiveBugReport(
          "Some checkers depend on this one! We don't allow dependency "
          "checkers to emit warnings, because checkers should depend on "
          "*modeling*, not *diagnostics*.");
+
+  assert(
+      bt.getCheckerName().startswith("debug") ||
+      !isHidden(ErrorNode->getState()
+                    ->getAnalysisManager()
+                    .getCheckerManager()
+                    ->getCheckerRegistryData(),
+                bt.getCheckerName()) &&
+          "Hidden checkers musn't emit diagnostics as they are by definition "
+          "non-user facing!");
 }
 
 void PathSensitiveBugReport::addVisitor(

clang/test/Analysis/std-c-library-functions-arg-constraints.c

@@ -2,7 +2,7 @@
 // RUN: %clang_analyze_cc1 %s \
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
-// RUN:   -analyzer-checker=alpha.apiModeling.StdCLibraryFunctionArgs \
+// RUN:   -analyzer-checker=alpha.unix.StdCLibraryFunctionArgs \
 // RUN:   -analyzer-checker=debug.StdCLibraryFunctionsTester \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -triple x86_64-unknown-linux-gnu \
@@ -12,7 +12,7 @@
 // RUN: %clang_analyze_cc1 %s \
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
-// RUN:   -analyzer-checker=alpha.apiModeling.StdCLibraryFunctionArgs \
+// RUN:   -analyzer-checker=alpha.unix.StdCLibraryFunctionArgs \
 // RUN:   -analyzer-checker=debug.StdCLibraryFunctionsTester \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -triple x86_64-unknown-linux-gnu \

clang/test/Analysis/std-c-library-functions-arg-constraints.cpp

@@ -1,7 +1,7 @@
 // RUN: %clang_analyze_cc1 %s \
 // RUN:   -analyzer-checker=core \
 // RUN:   -analyzer-checker=apiModeling.StdCLibraryFunctions \
-// RUN:   -analyzer-checker=alpha.apiModeling.StdCLibraryFunctionArgs \
+// RUN:   -analyzer-checker=alpha.unix.StdCLibraryFunctionArgs \
 // RUN:   -analyzer-checker=debug.StdCLibraryFunctionsTester \
 // RUN:   -analyzer-checker=debug.ExprInspection \
 // RUN:   -analyzer-config eagerly-assume=false \

clang/test/Analysis/weak-dependencies.c

@@ -1,5 +1,5 @@
 // RUN: %clang_analyze_cc1 %s -verify \
-// RUN:   -analyzer-checker=alpha.apiModeling.StdCLibraryFunctionArgs \
+// RUN:   -analyzer-checker=alpha.unix.StdCLibraryFunctionArgs \
 // RUN:   -analyzer-checker=core
 
 typedef __typeof(sizeof(int)) size_t;