[PATCH] D113754: [Analyzer][Core] Simplify IntSym in SValBuilder

[Gabor Marton via Phabricator via cfe-commits]

martong created this revision.
martong added reviewers: steakhal, ASDenysPetrov, NoQ, Szelethus.
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Make the SimpleSValBuilder capable to simplify existing IntSym
expressions based on a newly added constraint on the sub-expression.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D113754

Files:
  clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
  clang/test/Analysis/svalbuilder-simplify-intsym.cpp


Index: clang/test/Analysis/svalbuilder-simplify-intsym.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/svalbuilder-simplify-intsym.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_analyze_cc1 %s \
+// RUN:   -analyzer-checker=core \
+// RUN:   -analyzer-checker=debug.ExprInspection \
+// RUN:   -analyzer-config eagerly-assume=false \
+// RUN:   -verify
+
+// Here we test whether the SValBuilder is capable to simplify existing
+// IntSym expressions based on a newly added constraint on the sub-expression.
+
+void clang_analyzer_eval(bool);
+
+void test_SValBuilder_simplifies_IntSym(int x, int y) {
+  // Most IntSym BinOps are transformed to SymInt in SimpleSValBuilder.
+  // Division is one exception.
+  x = 77 / y;
+  if (y != 1)
+    return;
+  clang_analyzer_eval(x == 77);         // expected-warning{{TRUE}}
+  (void)(x * y);
+}
Index: clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -1183,6 +1183,19 @@
           S, SVB.evalBinOp(State, S->getOpcode(), LHS, RHS, S->getType()));
     }
 
+    SVal VisitIntSymExpr(const IntSymExpr *S) {
+      auto I = Cached.find(S);
+      if (I != Cached.end())
+        return I->second;
+
+      SVal RHS = Visit(S->getRHS());
+      if (isUnchanged(S->getRHS(), RHS))
+        return skip(S);
+      SVal LHS = SVB.makeIntVal(S->getLHS());
+      return cache(
+          S, SVB.evalBinOp(State, S->getOpcode(), LHS, RHS, S->getType()));
+    }
+
     SVal VisitSymSymExpr(const SymSymExpr *S) {
       auto I = Cached.find(S);
       if (I != Cached.end())


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