[clang] ffc32ef - [Analyzer][Core] Simplify IntSym in SValBuilder

[Gabor Marton via cfe-commits]

Author: Gabor Marton
Date: 2021-11-22T17:33:43+01:00
New Revision: ffc32efd1cd6a34659e2c559e9ba6ee923b1637a

URL: https://github.com/llvm/llvm-project/commit/ffc32efd1cd6a34659e2c559e9ba6ee923b1637a
DIFF: https://github.com/llvm/llvm-project/commit/ffc32efd1cd6a34659e2c559e9ba6ee923b1637a.diff

LOG: [Analyzer][Core] Simplify IntSym in SValBuilder

Make the SimpleSValBuilder capable to simplify existing IntSym
expressions based on a newly added constraint on the sub-expression.

Differential Revision: https://reviews.llvm.org/D113754

Added: 
    clang/test/Analysis/svalbuilder-simplify-intsym.cpp

Modified: 
    clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
index 681a1f64eadc..54a2386fc2ff 100644
--- a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -1183,6 +1183,19 @@ SVal SimpleSValBuilder::simplifySVal(ProgramStateRef State, SVal V) {
           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())

diff  --git a/clang/test/Analysis/svalbuilder-simplify-intsym.cpp b/clang/test/Analysis/svalbuilder-simplify-intsym.cpp
new file mode 100644
index 000000000000..8a58b797c86e
--- /dev/null
+++ b/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);
+}