[analyzer] Gain more precision retrieving the right SVal by specifying the type of the expression.

Thanks to Jordan for suggesting the fix.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179732 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 157 insertions, 1 deletions

diff --git a/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp b/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
index 11a1727645..7a0d370b81 100644
--- a/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
+++ b/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
@@ -997,7 +997,13 @@ bool bugreporter::trackNullOrUndefValue(const ExplodedNode *N,
   if (Optional<loc::MemRegionVal> L = V.getAs<loc::MemRegionVal>()) {
     // At this point we are dealing with the region's LValue.
     // However, if the rvalue is a symbolic region, we should track it as well.
-    SVal RVal = state->getSVal(L->getRegion());
+    // Try to use the correct type when looking up the value.
+    SVal RVal;
+    if (const Expr *E = dyn_cast<Expr>(S))
+      RVal = state->getRawSVal(L.getValue(), E->getType());
+    else
+      RVal = state->getSVal(L->getRegion());
+
     const MemRegion *RegionRVal = RVal.getAsRegion();
     report.addVisitor(new UndefOrNullArgVisitor(L->getRegion()));
 
diff --git a/test/Analysis/inlining/path-notes.c b/test/Analysis/inlining/path-notes.c
index d4fa461e5e..ff88f8203a 100644
--- a/test/Analysis/inlining/path-notes.c
+++ b/test/Analysis/inlining/path-notes.c
@@ -133,6 +133,13 @@ void test(struct Outer *wrapperPtr) {
                             // expected-note@-1 {{Dereference of null pointer (loaded from field 'p')}}
 }
 
+void test4(int **p) {
+  if (*p) return; // expected-note {{Taking false branch}}
+                  // expected-note@-1 {{Assuming pointer value is null}}
+  **p = 1; // expected-warning {{Dereference of null pointer}}
+           // expected-note@-1 {{Dereference of null pointer}}
+}
+
 // CHECK:  <key>diagnostics</key>
 // CHECK-NEXT:  <array>
 // CHECK-NEXT:   <dict>
@@ -3021,4 +3028,147 @@ void test(struct Outer *wrapperPtr) {
 // 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>137</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>137</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>137</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>137</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</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>137</integer>
+// CHECK-NEXT:       <key>col</key><integer>7</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>137</integer>
+// CHECK-NEXT:          <key>col</key><integer>7</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>137</integer>
+// CHECK-NEXT:          <key>col</key><integer>8</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>Assuming pointer value is null</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>Assuming pointer value is null</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>137</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>137</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</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>139</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>139</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>event</string>
+// CHECK-NEXT:      <key>location</key>
+// CHECK-NEXT:      <dict>
+// CHECK-NEXT:       <key>line</key><integer>139</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>139</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>139</integer>
+// CHECK-NEXT:          <key>col</key><integer>9</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>Dereference of null pointer</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>Dereference of null pointer</string>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:    </array>
+// CHECK-NEXT:    <key>description</key><string>Dereference of null pointer</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>test4</string>
+// CHECK-NEXT:   <key>issue_hash</key><string>3</string>
+// CHECK-NEXT:   <key>location</key>
+// CHECK-NEXT:   <dict>
+// CHECK-NEXT:    <key>line</key><integer>139</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:  </array>