[cfe-commits] r126305 - in /cfe/trunk: lib/Analysis/CFG.cpp test/Sema/exprs.c
Ted Kremenek
kremenek at apple.com
Tue Feb 22 21:11:46 PST 2011
Author: kremenek
Date: Tue Feb 22 23:11:46 2011
New Revision: 126305
URL: http://llvm.org/viewvc/llvm-project?rev=126305&view=rev
Log:
Teach CFGBuilder about null pointer constants in conditionals, and how they can be used to prune branches. Fixes false null pointer dereference warning in PR 8183.
Modified:
cfe/trunk/lib/Analysis/CFG.cpp
cfe/trunk/test/Sema/exprs.c
Modified: cfe/trunk/lib/Analysis/CFG.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/CFG.cpp?rev=126305&r1=126304&r2=126305&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/CFG.cpp (original)
+++ cfe/trunk/lib/Analysis/CFG.cpp Tue Feb 22 23:11:46 2011
@@ -17,6 +17,7 @@
#include "clang/AST/DeclCXX.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/AST/PrettyPrinter.h"
+#include "clang/AST/CharUnits.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Format.h"
@@ -413,9 +414,16 @@
Expr::EvalResult Result;
if (!S->isTypeDependent() && !S->isValueDependent() &&
- S->Evaluate(Result, *Context) && Result.Val.isInt())
- return Result.Val.getInt().getBoolValue();
-
+ S->Evaluate(Result, *Context)) {
+ if (Result.Val.isInt())
+ return Result.Val.getInt().getBoolValue();
+ if (Result.Val.isLValue()) {
+ Expr *e = Result.Val.getLValueBase();
+ const CharUnits &c = Result.Val.getLValueOffset();
+ if (!e && c.isZero())
+ return false;
+ }
+ }
return TryResult();
}
};
Modified: cfe/trunk/test/Sema/exprs.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/exprs.c?rev=126305&r1=126304&r2=126305&view=diff
==============================================================================
--- cfe/trunk/test/Sema/exprs.c (original)
+++ cfe/trunk/test/Sema/exprs.c Tue Feb 22 23:11:46 2011
@@ -18,6 +18,14 @@
return 0;
}
+// PR 8183 - Handle null pointer constants on the left-side of the '&&', and reason about
+// this when determining the reachability of the null pointer dereference on the right side.
+void pr8183(unsigned long long test)
+{
+ (void)((((void*)0)) && (*((unsigned long long*)(((void*)0))) = ((unsigned long long)((test)) % (unsigned long long)((1000000000))))); // no-warning
+ (*((unsigned long long*)(((void*)0))) = ((unsigned long long)((test)) % (unsigned long long)((1000000000)))); // expected-warning {{indirection of non-volatile null pointer will be deleted, not trap}} expected-note {{consider using __builtin_trap() or qualifying pointer with 'volatile'}}
+}
+
// PR1966
_Complex double test1() {
return __extension__ 1.0if;
More information about the cfe-commits
mailing list