[PATCH] D95799: [analyzer] Symbolicate float values with integral casting

[Denys Petrov via Phabricator via cfe-commits]

ASDenysPetrov updated this revision to Diff 321585.
ASDenysPetrov added a comment.

Updated. Moved comments as well.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D95799/new/

https://reviews.llvm.org/D95799

Files:
  clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
  clang/lib/StaticAnalyzer/Core/Store.cpp
  clang/test/Analysis/svalbuilder-float-cast.c


Index: clang/test/Analysis/svalbuilder-float-cast.c
===================================================================
--- clang/test/Analysis/svalbuilder-float-cast.c
+++ clang/test/Analysis/svalbuilder-float-cast.c
@@ -4,17 +4,23 @@
 
 void SymbolCast_of_float_type_aux(int *p) {
   *p += 0;
-  // FIXME: Ideally, all unknown values should be symbolicated.
-  clang_analyzer_denote(*p, "$x"); // expected-warning{{Not a symbol}}
+  clang_analyzer_denote(*p, "$x");
 
   *p += 1;
-  // This should NOT be (float)$x + 1. Symbol $x was never casted to float.
-  // FIXME: Ideally, this should be $x + 1.
-  clang_analyzer_express(*p); // expected-warning{{Not a symbol}}
+  // expected-warning at +3{{(float)$x + 1}}
+  // expected-warning at +2{{(double)$x + 1}}
+  // expected-warning at +1{{(long double)$x + 1}}
+  clang_analyzer_express(*p);
 }
 
 void SymbolCast_of_float_type() {
-  extern float x;
+  extern float x1;
+  extern double x2;
+  extern long double x3;
+
   void (*f)() = SymbolCast_of_float_type_aux;
-  f(&x);
+
+  f(&x1);
+  f(&x2);
+  f(&x3);
 }
Index: clang/lib/StaticAnalyzer/Core/Store.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/Store.cpp
+++ clang/lib/StaticAnalyzer/Core/Store.cpp
@@ -407,17 +407,6 @@
   if (castTy.isNull() || V.isUnknownOrUndef())
     return V;
 
-  // The dispatchCast() call below would convert the int into a float.
-  // What we want, however, is a bit-by-bit reinterpretation of the int
-  // as a float, which usually yields nothing garbage. For now skip casts
-  // from ints to floats.
-  // TODO: What other combinations of types are affected?
-  if (castTy->isFloatingType()) {
-    SymbolRef Sym = V.getAsSymbol();
-    if (Sym && !Sym->getType()->isFloatingType())
-      return UnknownVal();
-  }
-
   // When retrieving symbolic pointer and expecting a non-void pointer,
   // wrap them into element regions of the expected type if necessary.
   // SValBuilder::dispatchCast() doesn't do that, but it is necessary to
Index: clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
+++ clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
@@ -501,8 +501,13 @@
   if (getContext().getTypeSize(castTy) >= getContext().getTypeSize(originalTy))
     return evalCast(val, castTy, originalTy);
 
+  // The code call below would convert the int into a float.
+  // What we want, however, is a bit-by-bit reinterpretation of the int
+  // as a float, which usually yields nothing garbage.
+  // TODO: What other combinations of types are affected?
+  // Let evalCast handle non symbolic expressions and float symbols.
   SymbolRef se = val.getAsSymbol();
-  if (!se) // Let evalCast handle non symbolic expressions.
+  if (!se || se->getType()->isFloatingType())
     return evalCast(val, castTy, originalTy);
 
   // Find the maximum value of the target type.


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