On Nov 13, 2008, at 3:27 PM, Zhongxing Xu <[EMAIL PROTECTED]> wrote:
On Thu, Nov 13, 2008 at 11:03 PM, Ted Kremenek <[EMAIL PROTECTED]>
wrote:
On Nov 13, 2008, at 1:15 AM, Zhongxing Xu wrote:
Author: zhongxingxu
Date: Thu Nov 13 03:15:14 2008
New Revision: 59238
URL: http://llvm.org/viewvc/llvm-project?rev=59238&view=rev
Log:
Array index might be unsigned. We have to generate a temporary
signed value for
it to be evaluated by APSInt::operators.
Modified:
cfe/trunk/lib/Analysis/RegionStore.cpp
Modified: cfe/trunk/lib/Analysis/RegionStore.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/RegionStore.cpp?rev=59238&r1=59237&r2=59238&view=diff
===
===
===
=====================================================================
--- cfe/trunk/lib/Analysis/RegionStore.cpp (original)
+++ cfe/trunk/lib/Analysis/RegionStore.cpp Thu Nov 13 03:15:14 2008
@@ -197,6 +197,18 @@
// Only handle integer indices for now.
if ((CI1 = dyn_cast<nonloc::ConcreteInt>(&Idx)) &&
(CI2 = dyn_cast<nonloc::ConcreteInt>(&Offset))) {
+
+ // Temporary SVal to hold a potential signed APSInt.
+ SVal SignedInt;
+
+ // Index might be unsigned. We have to convert it to signed.
+ if (CI2->getValue().isUnsigned()) {
+ llvm::APSInt SI = CI2->getValue();
+ SI.setIsSigned(true);
+ SignedInt = nonloc::ConcreteInt(getBasicVals().getValue(SI));
+ CI2 = cast<nonloc::ConcreteInt>(&SignedInt);
+ }
+
Hi Zhongxing,
I'm not saying this isn't needed, but is there a particular
justification for the signed -> unsigned conversion? (I actually
don't know by just looking at your patch). It seems like things
like this should go in GRExprEngine, not the Store.
Consistent signedness is required by llvm::APSInt. So we should find
a place to handle this. May be we should ensure all ConcreteInt be
signed in GRExprEngine?
One question I have is whether or not this conversion is specified in
the C standard. I would like to have a clean way of handling pointer
arithmetic and integer overflow (which affects array indexing) and
that probably should be handled in GRExprEngine. GRExprEngine of
course could delegate specific micro-operations to Store/
ConstraintManager/etc as we already do now for various things.
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