[analyzer] Fix trackNullOrUndef when tracking args that have nil receivers.

There were actually two bugs here:
- if we decided to look for an interesting lvalue or call expression, we
  wouldn't go find its node if we also knew we were at a (different) call.
- if we looked through one message send with a  nil receiver, we thought we
  were still looking at an argument to the original call.

Put together, this kept us from being able to track the right values, which
means sub-par diagnostics and worse false-positive suppression.

Noticed by inspection.

llvm-svn: 180996

1 files changed, 342 insertions, 0 deletions

diff --git a/clang/test/Analysis/inlining/path-notes.m b/clang/test/Analysis/inlining/path-notes.m
index d660973ce19..74f088a382b 100644
--- a/clang/test/Analysis/inlining/path-notes.m
+++ b/clang/test/Analysis/inlining/path-notes.m
@@ -65,6 +65,31 @@ int testDispatchSyncInliningNoPruning(int coin) {
 }
 
 
+@interface PointerWrapper
+- (int *)getPtr;
+@end
+
+id getNil() {
+  return 0;
+}
+
+void testNilReceiverHelper(int *x) {
+  *x = 1; // expected-warning {{Dereference of null pointer}}
+  // expected-note@-1 {{Dereference of null pointer (loaded from variable 'x')}}
+}
+
+void testNilReceiver(id *x) {
+  if (*x) {
+    // expected-note@-1 {{Taking false branch}}
+    return;
+  }
+  testNilReceiverHelper([*x getPtr]);
+  // expected-note@-1 {{'getPtr' not called because the receiver is nil}}
+  // expected-note@-2 {{Passing null pointer value via 1st parameter 'x'}}
+  // expected-note@-3 {{Calling 'testNilReceiverHelper'}}
+}
+
+
 // CHECK:  <key>diagnostics</key>
 // CHECK-NEXT:  <array>
 // CHECK-NEXT:   <dict>
@@ -1012,4 +1037,321 @@ int testDispatchSyncInliningNoPruning(int coin) {
 // CHECK-NEXT:    <key>file</key><integer>0</integer>
 // CHECK-NEXT:   </dict>
 // CHECK-NEXT:   </dict>
+// CHECK-NEXT:   <dict>
+// CHECK-NEXT:    <key>path</key>
+// CHECK-NEXT:    <array>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>control</string>
+// CHECK-NEXT:      <key>edges</key>
+// CHECK-NEXT:       <array>
+// CHECK-NEXT:        <dict>
+// CHECK-NEXT:         <key>start</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>82</integer>
+// CHECK-NEXT:            <key>col</key><integer>3</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>82</integer>
+// CHECK-NEXT:            <key>col</key><integer>4</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:         <key>end</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>3</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>23</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:        </dict>
+// CHECK-NEXT:       </array>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>control</string>
+// CHECK-NEXT:      <key>edges</key>
+// CHECK-NEXT:       <array>
+// CHECK-NEXT:        <dict>
+// CHECK-NEXT:         <key>start</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>3</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>23</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:         <key>end</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>26</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>26</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:        </dict>
+// CHECK-NEXT:       </array>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>event</string>
+// CHECK-NEXT:      <key>location</key>
+// CHECK-NEXT:      <dict>
+// CHECK-NEXT:       <key>line</key><integer>86</integer>
+// CHECK-NEXT:       <key>col</key><integer>26</integer>
+// CHECK-NEXT:       <key>file</key><integer>0</integer>
+// CHECK-NEXT:      </dict>
+// CHECK-NEXT:      <key>ranges</key>
+// CHECK-NEXT:      <array>
+// CHECK-NEXT:        <array>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>86</integer>
+// CHECK-NEXT:          <key>col</key><integer>26</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>86</integer>
+// CHECK-NEXT:          <key>col</key><integer>27</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:        </array>
+// CHECK-NEXT:      </array>
+// CHECK-NEXT:      <key>depth</key><integer>0</integer>
+// CHECK-NEXT:      <key>extended_message</key>
+// CHECK-NEXT:      <string>&apos;getPtr&apos; not called because the receiver is nil</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>&apos;getPtr&apos; not called because the receiver is nil</string>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>control</string>
+// CHECK-NEXT:      <key>edges</key>
+// CHECK-NEXT:       <array>
+// CHECK-NEXT:        <dict>
+// CHECK-NEXT:         <key>start</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>26</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>26</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:         <key>end</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>25</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>86</integer>
+// CHECK-NEXT:            <key>col</key><integer>25</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:        </dict>
+// CHECK-NEXT:       </array>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>event</string>
+// CHECK-NEXT:      <key>location</key>
+// CHECK-NEXT:      <dict>
+// CHECK-NEXT:       <key>line</key><integer>86</integer>
+// CHECK-NEXT:       <key>col</key><integer>25</integer>
+// CHECK-NEXT:       <key>file</key><integer>0</integer>
+// CHECK-NEXT:      </dict>
+// CHECK-NEXT:      <key>ranges</key>
+// CHECK-NEXT:      <array>
+// CHECK-NEXT:        <array>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>86</integer>
+// CHECK-NEXT:          <key>col</key><integer>25</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>86</integer>
+// CHECK-NEXT:          <key>col</key><integer>35</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:        </array>
+// CHECK-NEXT:      </array>
+// CHECK-NEXT:      <key>depth</key><integer>0</integer>
+// CHECK-NEXT:      <key>extended_message</key>
+// CHECK-NEXT:      <string>Passing null pointer value via 1st parameter &apos;x&apos;</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>Passing null pointer value via 1st parameter &apos;x&apos;</string>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>event</string>
+// CHECK-NEXT:      <key>location</key>
+// CHECK-NEXT:      <dict>
+// CHECK-NEXT:       <key>line</key><integer>86</integer>
+// CHECK-NEXT:       <key>col</key><integer>3</integer>
+// CHECK-NEXT:       <key>file</key><integer>0</integer>
+// CHECK-NEXT:      </dict>
+// CHECK-NEXT:      <key>ranges</key>
+// CHECK-NEXT:      <array>
+// CHECK-NEXT:        <array>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>86</integer>
+// CHECK-NEXT:          <key>col</key><integer>3</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>86</integer>
+// CHECK-NEXT:          <key>col</key><integer>36</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:        </array>
+// CHECK-NEXT:      </array>
+// CHECK-NEXT:      <key>depth</key><integer>0</integer>
+// CHECK-NEXT:      <key>extended_message</key>
+// CHECK-NEXT:      <string>Calling &apos;testNilReceiverHelper&apos;</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>Calling &apos;testNilReceiverHelper&apos;</string>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>event</string>
+// CHECK-NEXT:      <key>location</key>
+// CHECK-NEXT:      <dict>
+// CHECK-NEXT:       <key>line</key><integer>76</integer>
+// CHECK-NEXT:       <key>col</key><integer>1</integer>
+// CHECK-NEXT:       <key>file</key><integer>0</integer>
+// CHECK-NEXT:      </dict>
+// CHECK-NEXT:      <key>depth</key><integer>1</integer>
+// CHECK-NEXT:      <key>extended_message</key>
+// CHECK-NEXT:      <string>Entered call from &apos;testNilReceiver&apos;</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>Entered call from &apos;testNilReceiver&apos;</string>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>control</string>
+// CHECK-NEXT:      <key>edges</key>
+// CHECK-NEXT:       <array>
+// CHECK-NEXT:        <dict>
+// CHECK-NEXT:         <key>start</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>76</integer>
+// CHECK-NEXT:            <key>col</key><integer>1</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>76</integer>
+// CHECK-NEXT:            <key>col</key><integer>4</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:         <key>end</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>77</integer>
+// CHECK-NEXT:            <key>col</key><integer>3</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>77</integer>
+// CHECK-NEXT:            <key>col</key><integer>3</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:        </dict>
+// CHECK-NEXT:       </array>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>control</string>
+// CHECK-NEXT:      <key>edges</key>
+// CHECK-NEXT:       <array>
+// CHECK-NEXT:        <dict>
+// CHECK-NEXT:         <key>start</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>77</integer>
+// CHECK-NEXT:            <key>col</key><integer>3</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>77</integer>
+// CHECK-NEXT:            <key>col</key><integer>3</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:         <key>end</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>77</integer>
+// CHECK-NEXT:            <key>col</key><integer>6</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>77</integer>
+// CHECK-NEXT:            <key>col</key><integer>6</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:        </dict>
+// CHECK-NEXT:       </array>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>event</string>
+// CHECK-NEXT:      <key>location</key>
+// CHECK-NEXT:      <dict>
+// CHECK-NEXT:       <key>line</key><integer>77</integer>
+// CHECK-NEXT:       <key>col</key><integer>6</integer>
+// CHECK-NEXT:       <key>file</key><integer>0</integer>
+// CHECK-NEXT:      </dict>
+// CHECK-NEXT:      <key>ranges</key>
+// CHECK-NEXT:      <array>
+// CHECK-NEXT:        <array>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>77</integer>
+// CHECK-NEXT:          <key>col</key><integer>4</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>77</integer>
+// CHECK-NEXT:          <key>col</key><integer>4</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:        </array>
+// CHECK-NEXT:      </array>
+// CHECK-NEXT:      <key>depth</key><integer>1</integer>
+// CHECK-NEXT:      <key>extended_message</key>
+// CHECK-NEXT:      <string>Dereference of null pointer (loaded from variable &apos;x&apos;)</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>Dereference of null pointer (loaded from variable &apos;x&apos;)</string>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:    </array>
+// CHECK-NEXT:    <key>description</key><string>Dereference of null pointer (loaded from variable &apos;x&apos;)</string>
+// CHECK-NEXT:    <key>category</key><string>Logic error</string>
+// CHECK-NEXT:    <key>type</key><string>Dereference of null pointer</string>
+// CHECK-NEXT:   <key>issue_context_kind</key><string>function</string>
+// CHECK-NEXT:   <key>issue_context</key><string>testNilReceiverHelper</string>
+// CHECK-NEXT:   <key>issue_hash</key><string>1</string>
+// CHECK-NEXT:   <key>location</key>
+// CHECK-NEXT:   <dict>
+// CHECK-NEXT:    <key>line</key><integer>77</integer>
+// CHECK-NEXT:    <key>col</key><integer>6</integer>
+// CHECK-NEXT:    <key>file</key><integer>0</integer>
+// CHECK-NEXT:   </dict>
+// CHECK-NEXT:   </dict>
 // CHECK-NEXT:  </array>