Add missing boundary checks to variable completion.

[teemperor]

Summary

Stopgap patch to at least stop all the crashes I get from this code.

[teemperor]

• Fixed formatting.

[jingham]

One trivial fix to the test case.

packages/Python/lldbsuite/test/functionalities/completion/TestCompletion.py

def test_at(self):
         self.complete_from_to('at', 'attach ')
 
     @skipIfFreeBSD  # timing out on the FreeBSD buildbot
     def test_de(self):
         """Test that 'de' completes to 'detach '."""
         self.complete_from_to('de', 'detach ')
 
     @skipIfFreeBSD  # timing out on the FreeBSD buildbot
+    def test_frame_variable(self):
+        self.build()
+        self.main_source = "main.cpp"
+        self.main_source_spec = lldb.SBFileSpec(self.main_source)
+        self.dbg.CreateTarget(self.getBuildArtifact("a.out"))
+
+        (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(self,
+                                          '// Break here', self.main_source_spec)
+        self.assertEquals(process.GetState(), lldb.eStateStopped)
+        # FIXME: This pulls in the debug information to make the completions work,
+        # but the completions should also work without.
+        self.runCmd("frame variable fooo")
+
+        self.complete_from_to('frame variable fo',
+                              'frame variable fooo')
+        self.complete_from_to('frame variable fooo.',
+                              'frame variable fooo.')
+        self.complete_from_to('frame variable fooo.dd',
+                              'frame variable fooo.dd')
+
+        self.complete_from_to('frame variable ptr_fooo->',
+                              'frame variable ptr_fooo->')
+        self.complete_from_to('frame variable ptr_fooo->dd',
+                              'frame variable ptr_fooo->dd')
+
+        self.complete_from_to('frame variable cont',
+                              'frame variable container')
+        self.complete_from_to('frame variable container.',
+                              'frame variable container.MemberVar')
+        self.complete_from_to('frame variable container.Mem',
+                              'frame variable container.MemberVar')
+
+        self.complete_from_to('frame variable ptr_cont',
+                              'frame variable ptr_container')
+        self.complete_from_to('frame variable ptr_container->',
+                              'frame variable ptr_container->MemberVar')
+        self.complete_from_to('frame variable ptr_container->Mem',
+                              'frame variable ptr_container->MemberVar')
+
+    @skipIfFreeBSD  # timing out on the FreeBSD buildbot
     def test_process_attach_dash_dash_con(self):
         """Test that 'process attach --con' completes to 'process attach --continue '."""
         self.complete_from_to(
             'process attach --con',
             'process attach --continue ')
 
     # <rdar://problem/11052829>
     @skipIfFreeBSD  # timing out on the FreeBSD buildbot

packages/Python/lldbsuite/test/functionalities/completion/main.cpp

 class Foo
 {
 public:
     int Bar(int x, int y)
     {
         return x + y;
     }
 };
 
+struct Container { int MemberVar; };
+
 int main()
 {
-    Foo f;
-    f.Bar(1, 2);
+    Foo fooo;
+    Foo *ptr_fooo = &fooo;
+    fooo.Bar(1, 2);
+
+    Container container;
+    Container *ptr_container = &container;
+    return container.MemberVar = 3; // Break here
 }

source/Symbol/Variable.cpp

if (partial_path.empty()) {
     case '&':
       if (prefix_path.isTriviallyEmpty()) {
         PrivateAutoComplete(frame, partial_path.substr(1), std::string("&"),
                             compiler_type, matches, word_complete);
       }
       break;
 
     case '-':
-      if (partial_path[1] == '>' && !prefix_path.str().empty()) {
+      if (partial_path.size() > 1 && partial_path[1] == '>' &&
+          !prefix_path.str().empty()) {
         switch (type_class) {
         case lldb::eTypeClassPointer: {
           CompilerType pointee_type(compiler_type.GetPointeeType());
-          if (partial_path[2]) {
+          if (partial_path.size() > 2 && partial_path[2]) {
             // If there is more after the "->", then search deeper
             PrivateAutoComplete(
                 frame, partial_path.substr(2), prefix_path + "->",
                 pointee_type.GetCanonicalType(), matches, word_complete);
           } else {
             // Nothing after the "->", so list all members
             PrivateAutoCompleteMembers(
                 frame, std::string(), std::string(), prefix_path + "->",
                 pointee_type.GetCanonicalType(), matches, word_complete);
           }
         } break;
         default:
           break;
         }
       }
       break;
 
     case '.':
       if (compiler_type.IsValid()) {
         switch (type_class) {
         case lldb::eTypeClassUnion:
         case lldb::eTypeClassStruct:
         case lldb::eTypeClassClass:
-          if (partial_path[1]) {
+          if (partial_path.size() > 1 && partial_path[1]) {
             // If there is more after the ".", then search deeper
             PrivateAutoComplete(frame, partial_path.substr(1),
                                 prefix_path + ".", compiler_type, matches,
                                 word_complete);
 
           } else {
             // Nothing after the ".", so list all members
             PrivateAutoCompleteMembers(frame, std::string(), partial_path,