[PATCH] D58067: [Analyzer] Crash fix for FindLastStoreBRVisitor

[Balogh , Ádám via Phabricator via cfe-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rC353943: [Analyzer] Crash fix for FindLastStoreBRVisitor 
(authored by baloghadamsoftware, committed by ).

Changed prior to commit:
  https://reviews.llvm.org/D58067?vs=186470&id=186625#toc

Repository:
  rC Clang

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D58067/new/

https://reviews.llvm.org/D58067

Files:
  lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
  test/Analysis/PR40625.cpp
  test/Analysis/uninit-vals.m


Index: lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
===================================================================
--- lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
+++ lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
@@ -153,6 +153,32 @@
   return E;
 }
 
+/// Comparing internal representations of symbolic values (via
+/// SVal::operator==()) is a valid way to check if the value was updated,
+/// unless it's a LazyCompoundVal that may have a different internal
+/// representation every time it is loaded from the state. In this function we
+/// do an approximate comparison for lazy compound values, checking that they
+/// are the immediate snapshots of the tracked region's bindings within the
+/// node's respective states but not really checking that these snapshots
+/// actually contain the same set of bindings.
+bool hasVisibleUpdate(const ExplodedNode *LeftNode, SVal LeftVal,
+                      const ExplodedNode *RightNode, SVal RightVal) {
+  if (LeftVal == RightVal)
+    return true;
+
+  const auto LLCV = LeftVal.getAs<nonloc::LazyCompoundVal>();
+  if (!LLCV)
+    return false;
+
+  const auto RLCV = RightVal.getAs<nonloc::LazyCompoundVal>();
+  if (!RLCV)
+    return false;
+
+  return LLCV->getRegion() == RLCV->getRegion() &&
+    LLCV->getStore() == LeftNode->getState()->getStore() &&
+    RLCV->getStore() == RightNode->getState()->getStore();
+}
+
 //===----------------------------------------------------------------------===//
 // Definitions for bug reporter visitors.
 //===----------------------------------------------------------------------===//
@@ -1177,7 +1203,7 @@
     if (Succ->getState()->getSVal(R) != V)
       return nullptr;
 
-    if (Pred->getState()->getSVal(R) == V) {
+    if (hasVisibleUpdate(Pred, Pred->getState()->getSVal(R), Succ, V)) {
       Optional<PostStore> PS = Succ->getLocationAs<PostStore>();
       if (!PS || PS->getLocationValue() != R)
         return nullptr;
@@ -1198,6 +1224,7 @@
     // UndefinedVal.)
     if (Optional<CallEnter> CE = Succ->getLocationAs<CallEnter>()) {
       if (const auto *VR = dyn_cast<VarRegion>(R)) {
+
         const auto *Param = cast<ParmVarDecl>(VR->getDecl());
 
         ProgramStateManager &StateMgr = BRC.getStateManager();
Index: test/Analysis/PR40625.cpp
===================================================================
--- test/Analysis/PR40625.cpp
+++ test/Analysis/PR40625.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_analyze_cc1 -std=c++11 -analyzer-checker=core,alpha.core.CallAndMessageUnInitRefArg  %s -verify
+
+void f(const int *end);
+
+void g(const int (&arrr)[10]) {
+  f(arrr+sizeof(arrr)); // expected-warning{{1st function call argument is a pointer to uninitialized value}}
+  // FIXME: This is a false positive that should be fixed. Until then this
+  //        tests the crash fix in FindLastStoreBRVisitor (beside
+  //        uninit-vals.m).
+}
+
+void h() {
+  int arr[10];
+
+  g(arr);
+}
Index: test/Analysis/uninit-vals.m
===================================================================
--- test/Analysis/uninit-vals.m
+++ test/Analysis/uninit-vals.m
@@ -394,11 +394,11 @@
   struct {
     int : 4;
     int y : 4;
-  } a, b, c;
+  } a, b, c; // expected-note{{'c' initialized here}}
 
   a.y = 2;
 
-  b = a; // expected-note{{Value assigned to 'c'}}
+  b = a;
   clang_analyzer_eval(b.y == 2); // expected-warning{{TRUE}}
                                  // expected-note@-1{{TRUE}}
 
@@ -411,11 +411,11 @@
   struct {
     int x : 4;
     int : 4;
-  } a, b, c;
+  } a, b, c; // expected-note{{'c' initialized here}}
 
   a.x = 1;
 
-  b = a; // expected-note{{Value assigned to 'c'}}
+  b = a;
   clang_analyzer_eval(b.x == 1); // expected-warning{{TRUE}}
                                  // expected-note@-1{{TRUE}}
 

_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits