[PATCH] D124239: [analyzer] Fix ValistChecker false-positive involving symbolic pointers

Bal√°zs Benics via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Fri Apr 22 07:45:33 PDT 2022


steakhal updated this revision to Diff 424478.
steakhal added a comment.

fix test


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124239/new/

https://reviews.llvm.org/D124239

Files:
  clang/lib/StaticAnalyzer/Checkers/ValistChecker.cpp
  clang/test/Analysis/valist-uninitialized-no-undef.c


Index: clang/test/Analysis/valist-uninitialized-no-undef.c
===================================================================
--- clang/test/Analysis/valist-uninitialized-no-undef.c
+++ clang/test/Analysis/valist-uninitialized-no-undef.c
@@ -16,11 +16,20 @@
 
 void f6(va_list *fst, ...) {
   va_start(*fst, fst);
-  // FIXME: There should be no warning for this.
-  (void)va_arg(*fst, int); // expected-warning{{va_arg() is called on an uninitialized va_list}}
-  // expected-note at -1{{va_arg() is called on an uninitialized va_list}}
+  (void)va_arg(*fst, int);
   va_end(*fst);
-} 
+}
+
+int va_list_get_int(va_list *va) {
+  return va_arg(*va, int); // no-warning
+}
+
+struct MyVaList {
+  va_list l;
+};
+int va_list_get_int2(struct MyVaList *va) {
+  return va_arg(va->l, int); // no-warning
+}
 
 void call_vprintf_bad(int isstring, ...) {
   va_list va;
Index: clang/lib/StaticAnalyzer/Checkers/ValistChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/ValistChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/ValistChecker.cpp
@@ -178,7 +178,7 @@
     if (isa<ParmVarDecl>(DeclReg->getDecl()))
       Reg = C.getState()->getSVal(SV.castAs<Loc>()).getAsRegion();
   }
-  IsSymbolic = Reg && Reg->getAs<SymbolicRegion>();
+  IsSymbolic = Reg && Reg->getBaseRegion()->getAs<SymbolicRegion>();
   // Some VarRegion based VA lists reach here as ElementRegions.
   const auto *EReg = dyn_cast_or_null<ElementRegion>(Reg);
   return (EReg && VaListModelledAsArray) ? EReg->getSuperRegion() : Reg;


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