[analyzer] Fix hidden node traversal in exploded graph dumps.

The joined nodes now actually have the same state. That was intended
from the start but the original implementation turned out to be buggy.

Differential Revision: https://reviews.llvm.org/D69150

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@375278 91177308-0d34-0410-b5e6-96231b3b80d8

lib/StaticAnalyzer/Core/ExprEngine.cpp

@@ -3030,22 +3030,16 @@ struct DOTGraphTraits<ExplodedGraph*> : public DefaultDOTGraphTraits {
       llvm::function_ref<void(const ExplodedNode *)> PreCallback,
       llvm::function_ref<void(const ExplodedNode *)> PostCallback,
       llvm::function_ref<bool(const ExplodedNode *)> Stop) {
-    const ExplodedNode *FirstHiddenNode = N;
-    while (FirstHiddenNode->pred_size() == 1 &&
-           isNodeHidden(*FirstHiddenNode->pred_begin())) {
-      FirstHiddenNode = *FirstHiddenNode->pred_begin();
-    }
-    const ExplodedNode *OtherNode = FirstHiddenNode;
     while (true) {
-      PreCallback(OtherNode);
-      if (Stop(OtherNode))
+      PreCallback(N);
+      if (Stop(N))
         return true;
 
-      if (OtherNode == N)
+      if (N->succ_size() != 1 || !isNodeHidden(N->getFirstSucc()))
         break;
-      PostCallback(OtherNode);
+      PostCallback(N);
 
-      OtherNode = *OtherNode->succ_begin();
+      N = N->getFirstSucc();
     }
     return false;
   }

test/Analysis/dump_egraph.c

@@ -18,10 +18,30 @@ int foo() {
   return *x + *y;
 }
 
-// CHECK: \"program_points\": [\l    \{ \"kind\": \"Edge\", \"src_id\": 2, \"dst_id\": 1, \"terminator\": null, \"term_kind\": null, \"tag\": null, \"node_id\": 1, \"is_sink\": 0, \"has_report\": 0 \}\l  ],\l  \"program_state\": null
-
-// CHECK: \"program_points\": [\l    \{ \"kind\": \"BlockEntrance\", \"block_id\": 1
-
+// CHECK: \"program_points\": [\l
+// CHECK-SAME: \{ \"kind\": \"Edge\", \"src_id\": 2, \"dst_id\": 1,
+// CHECK-SAME:    \"terminator\": null, \"term_kind\": null, \"tag\": null,
+// CHECK-SAME:    \"node_id\": 1, \"is_sink\": 0, \"has_report\": 0
+// CHECK-SAME: \},
+// CHECK-SAME: \{ \"kind\": \"BlockEntrance\", \"block_id\": 1, \"tag\": null,
+// CHECK-SAME:    \"node_id\": 2, \"is_sink\": 0, \"has_report\": 0
+// CHECK-SAME: \},
+// CHECK-SAME: \{ \"kind\": \"Statement\", \"stmt_kind\": \"IntegerLiteral\",
+// CHECK-SAME:    \"stmt_id\": 597, \"pointer\": \"0x{{[0-9a-f]*}}\",
+// CHECK-SAME:    \"pretty\": \"0\", \"location\": \{
+// CHECK-SAME:        \"line\": 15, \"column\": 12, \"file\":
+// CHECK-SAME:    \}, \"stmt_point_kind\": \"PreStmtPurgeDeadSymbols\",
+// CHECK-SAME:    \"tag\": \"ExprEngine : Clean Node\", \"node_id\": 3,
+// CHECK-SAME:    \"is_sink\": 0, \"has_report\": 0
+// CHECK-SAME: \},
+// CHECK-SAME: \{ \"kind\": \"Statement\", \"stmt_kind\": \"IntegerLiteral\",
+// CHECK-SAME:    \"stmt_id\": 597, \"pointer\": \"0x{{[0-9a-f]*}}\",
+// CHECK-SAME:    \"pretty\": \"0\", \"location\": \{
+// CHECK-SAME:        \"line\": 15, \"column\": 12, \"file\":
+// CHECK-SAME:    \}, \"stmt_point_kind\": \"PostStmt\", \"tag\": null,
+// CHECK-SAME:    \"node_id\": 4, \"is_sink\": 0, \"has_report\": 0
+// CHECK-SAME: \}
+// CHECK-SAME: ]
 
 // CHECK: \"pretty\": \"*x\", \"location\": \{ \"line\": 18, \"column\": 10, \"file\": \"{{(.+)}}dump_egraph.c\" \}