[PATCH] D102240: [analyzer][solver] Prevent use of a null state

[Valeriy Savchenko via Phabricator via cfe-commits]

vsavchenko created this revision.
vsavchenko added reviewers: NoQ, martong, steakhal.
Herald added subscribers: ASDenysPetrov, dkrupp, donat.nagy, Szelethus, mikhail.ramalho, a.sidorin, rnkovacs, szepet, baloghadamsoftware, xazax.hun.
vsavchenko requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

rdar://77686137


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D102240

Files:
  clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
  clang/test/Analysis/PR50268.c


Index: clang/test/Analysis/PR50268.c
===================================================================
--- /dev/null
+++ clang/test/Analysis/PR50268.c
@@ -0,0 +1,12 @@
+// RUN: %clang_analyze_cc1 -w -analyzer-checker=core -verify %s
+
+// expected-no-diagnostics
+
+unsigned long a, c;
+int b;
+void d() {
+  c -= a;
+  0 >= b;
+  c != b;
+  c ? 0 : 2; // expected no crash
+}
Index: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
+++ clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp
@@ -1487,15 +1487,18 @@
       // This is an infeasible assumption.
       return nullptr;
 
-    ProgramStateRef NewState = setConstraint(State, Sym, NewConstraint);
-    if (auto Equality = EqualityInfo::extract(Sym, Int, Adjustment)) {
-      // If the original assumption is not Sym + Adjustment !=/</> Int,
-      // we should invert IsEquality flag.
-      Equality->IsEquality = Equality->IsEquality != EQ;
-      return track(NewState, *Equality);
+    if (ProgramStateRef NewState = setConstraint(State, Sym, NewConstraint)) {
+      if (auto Equality = EqualityInfo::extract(Sym, Int, Adjustment)) {
+        // If the original assumption is not Sym + Adjustment !=/</> Int,
+        // we should invert IsEquality flag.
+        Equality->IsEquality = Equality->IsEquality != EQ;
+        return track(NewState, *Equality);
+      }
+
+      return NewState;
     }
 
-    return NewState;
+    return nullptr;
   }
 
   ProgramStateRef track(ProgramStateRef State, EqualityInfo ToTrack) {


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