[clang-tidy] cert-err58-cpp should not apply to function scope objects

[malcolm.parsons]

Summary

https://www.securecoding.cert.org/confluence/display/cplusplus/ERR58-CPP.+Constructors+of+objects+with+static+or+thread+storage+duration+must+not+throw+exceptions says:
Exceptions thrown in destructors of objects with static storage duration or in
constructors of namespace scope objects with static storage duration are not
caught by a function-try-block on main() . Exceptions thrown in destructors of
objects with thread storage duration or in constructors of namespace-scope
objects with thread storage duration are not caught by a function-try-block on
the initial function of the thread.

Function scope static objects are constructed when required by the function, so
exceptions can be caught from main().

Change cert-err58-cpp check to not apply to function/method scope objects.
Update tests.

[aaron.ballman]

LGTM!

Good catch, I will fix up the CERT rule to match the check accordingly. Thank you for this!

[malcolm.parsons]

I don't have commit access, so please commit it for me.
Thanks.

[aaron.ballman]

Commit in r282409

clang-tidy/cert/StaticObjectExceptionCheck.cpp

 void StaticObjectExceptionCheck::registerMatchers(MatchFinder *Finder) {
   if (!getLangOpts().CPlusPlus)
     return;
 
   // Match any static or thread_local variable declaration that is initialized
   // with a constructor that can throw.
   Finder->addMatcher(
       varDecl(anyOf(hasThreadStorageDuration(), hasStaticStorageDuration()),
+              unless(hasAncestor(functionDecl())),
               hasInitializer(cxxConstructExpr(hasDeclaration(
-                  cxxConstructorDecl(unless(isNoThrow()))
-                      .bind("ctor")))))
+                  cxxConstructorDecl(unless(isNoThrow())).bind("ctor")))))
           .bind("var"),
       this);
 }
 
 void StaticObjectExceptionCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *VD = Result.Nodes.getNodeAs<VarDecl>("var");
   const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor");
 

test/clang-tidy/cert-static-object-exception.cpp

 T t; // ok
 U u;
 // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: construction of 'u' with static storage duration may throw an exception that cannot be caught
 // CHECK-MESSAGES: 12:3: note: possibly throwing constructor declared here
 V v("v");
 // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: construction of 'v' with static storage duration may throw an exception that cannot be caught
 // CHECK-MESSAGES: 16:12: note: possibly throwing constructor declared here
 
+thread_local S s3;
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: construction of 's3' with thread_local storage duration may throw an exception that cannot be caught
+thread_local T t3; // ok
+thread_local U u3;
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: construction of 'u3' with thread_local storage duration may throw an exception that cannot be caught
+thread_local V v3("v");
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: construction of 'v3' with thread_local storage duration may throw an exception that cannot be caught
+
 void f(S s1, T t1, U u1, V v1) { // ok, ok, ok, ok
   S s2; // ok
   T t2; // ok
   U u2; // ok
   V v2("v"); // ok
 
-  thread_local S s3;
-  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: construction of 's3' with thread_local storage duration may throw an exception that cannot be caught
-  thread_local T t3; // ok
-  thread_local U u3;
-  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: construction of 'u3' with thread_local storage duration may throw an exception that cannot be caught
-  thread_local V v3("v");
-  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: construction of 'v3' with thread_local storage duration may throw an exception that cannot be caught
+  thread_local S s3; // ok
+  thread_local T t3; // ok
+  thread_local U u3; // ok
+  thread_local V v3("v"); // ok
+
+  static S s4; // ok
+  static T t4; // ok
+  static U u4; // ok
+  static V v4("v"); // ok
+}
+
+namespace {
+S s;
+// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: construction of 's' with static storage duration may throw an exception that cannot be caught [cert-err58-cpp]
+// CHECK-MESSAGES: 4:3: note: possibly throwing constructor declared here
+T t; // ok
+U u;
+// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: construction of 'u' with static storage duration may throw an exception that cannot be caught
+// CHECK-MESSAGES: 12:3: note: possibly throwing constructor declared here
+V v("v");
+// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: construction of 'v' with static storage duration may throw an exception that cannot be caught
+// CHECK-MESSAGES: 16:12: note: possibly throwing constructor declared here
+
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: construction of 's3' with thread_local storage duration may throw an exception that cannot be caught
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: construction of 'u3' with thread_local storage duration may throw an exception that cannot be caught
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: construction of 'v3' with thread_local storage duration may throw an exception that cannot be caught
+};
+
+class Statics {
+  static S s;
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 's' with static storage duration may throw an exception that cannot be caught [cert-err58-cpp]
+  // CHECK-MESSAGES: 4:3: note: possibly throwing constructor declared here
+  static T t; // ok
+  static U u;
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 'u' with static storage duration may throw an exception that cannot be caught
+  // CHECK-MESSAGES: 12:3: note: possibly throwing constructor declared here
+  static V v;
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 'v' with static storage duration may throw an exception that cannot be caught
+  // CHECK-MESSAGES: 16:12: note: possibly throwing constructor declared here
 
-  static S s4;
-  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 's4' with static storage duration may throw an exception that cannot be caught
-  static T t4; // ok
-  static U u4;
-  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 'u4' with static storage duration may throw an exception that cannot be caught
-  static V v4("v");
-  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 'v4' with static storage duration may throw an exception that cannot be caught
+  void f(S s, T t, U u, V v) {
+    S s2;      // ok
+    T t2;      // ok
+    U u2;      // ok
+    V v2("v"); // ok
+
+    thread_local S s3;      // ok
+    thread_local T t3;      // ok
+    thread_local U u3;      // ok
+    thread_local V v3("v"); // ok
+
+    static S s4;      // ok
+    static T t4;      // ok
+    static U u4;      // ok
+    static V v4("v"); // ok
   }
+};
+
+S Statics::s;
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 's' with static storage duration may throw an exception that cannot be caught [cert-err58-cpp]
+// CHECK-MESSAGES: 4:3: note: possibly throwing constructor declared here
+T Statics::t;
+U Statics::u;
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 'u' with static storage duration may throw an exception that cannot be caught
+// CHECK-MESSAGES: 12:3: note: possibly throwing constructor declared here
+V Statics::v("v");
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: construction of 'v' with static storage duration may throw an exception that cannot be caught
+// CHECK-MESSAGES: 16:12: note: possibly throwing constructor declared here