[cfe-commits] r61419 - /cfe/trunk/lib/Analysis/RegionStore.cpp
Ted Kremenek
kremenek at apple.com
Tue Dec 23 23:46:34 PST 2008
Author: kremenek
Date: Wed Dec 24 01:46:32 2008
New Revision: 61419
URL: http://llvm.org/viewvc/llvm-project?rev=61419&view=rev
Log:
Add a bunch of comments and FIXMEs.
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=61419&r1=61418&r2=61419&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/RegionStore.cpp (original)
+++ cfe/trunk/lib/Analysis/RegionStore.cpp Wed Dec 24 01:46:32 2008
@@ -124,10 +124,21 @@
const GRState* BindCompoundLiteral(const GRState* St,
const CompoundLiteralExpr* CL, SVal V);
+ /// getLValueString - Returns an SVal representing the lvalue of a
+ /// StringLiteral. Within RegionStore a StringLiteral has an
+ /// associated StringRegion, and the lvalue of a StringLiteral is
+ /// the lvalue of that region.
SVal getLValueString(const GRState* St, const StringLiteral* S);
+ /// getLValueCompoundLiteral - Returns an SVal representing the
+ /// lvalue of a compound literal. Within RegionStore a compound
+ /// literal has an associated region, and the lvalue of the
+ /// compound literal is the lvalue of that region.
SVal getLValueCompoundLiteral(const GRState* St, const CompoundLiteralExpr*);
+ /// getLValueVar - Returns an SVal that represents the lvalue of a
+ /// variable. Within RegionStore a variable has an associated
+ /// VarRegion, and the lvalue of the variable is the lvalue of that region.
SVal getLValueVar(const GRState* St, const VarDecl* VD);
SVal getLValueIvar(const GRState* St, const ObjCIvarDecl* D, SVal Base);
@@ -138,6 +149,12 @@
SVal getSizeInElements(const GRState* St, const MemRegion* R);
+ /// ArrayToPointer - Emulates the "decay" of an array to a pointer
+ /// type. 'Array' represents the lvalue of the array being decayed
+ /// to a pointer, and the returned SVal represents the decayed
+ /// version of that lvalue (i.e., a pointer to the first element of
+ /// the array). This is called by GRExprEngine when evaluating
+ /// casts from arrays to pointers.
SVal ArrayToPointer(SVal Array);
/// CastRegion - Used by GRExprEngine::VisitCast to handle casts from
@@ -232,17 +249,30 @@
return new RegionStoreManager(StMgr);
}
+
+/// getLValueString - Returns an SVal representing the lvalue of a
+/// StringLiteral. Within RegionStore a StringLiteral has an
+/// associated StringRegion, and the lvalue of a StringLiteral is the
+/// lvalue of that region.
SVal RegionStoreManager::getLValueString(const GRState* St,
const StringLiteral* S) {
return loc::MemRegionVal(MRMgr.getStringRegion(S));
}
+/// getLValueVar - Returns an SVal that represents the lvalue of a
+/// variable. Within RegionStore a variable has an associated
+/// VarRegion, and the lvalue of the variable is the lvalue of that region.
SVal RegionStoreManager::getLValueVar(const GRState* St, const VarDecl* VD) {
return loc::MemRegionVal(MRMgr.getVarRegion(VD));
}
-SVal RegionStoreManager::getLValueCompoundLiteral(const GRState* St,
- const CompoundLiteralExpr* CL) {
+/// getLValueCompoundLiteral - Returns an SVal representing the lvalue
+/// of a compound literal. Within RegionStore a compound literal
+/// has an associated region, and the lvalue of the compound literal
+/// is the lvalue of that region.
+SVal
+RegionStoreManager::getLValueCompoundLiteral(const GRState* St,
+ const CompoundLiteralExpr* CL) {
return loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL));
}
@@ -403,9 +433,15 @@
assert(0 && "Other regions are not supported yet.");
}
-// Cast 'pointer to array' to 'pointer to the first element of array'.
-
+/// ArrayToPointer - Emulates the "decay" of an array to a pointer
+/// type. 'Array' represents the lvalue of the array being decayed
+/// to a pointer, and the returned SVal represents the decayed
+/// version of that lvalue (i.e., a pointer to the first element of
+/// the array). This is called by GRExprEngine when evaluating casts
+/// from arrays to pointers.
SVal RegionStoreManager::ArrayToPointer(SVal Array) {
+ // FIXME: This should be factored into GRExprEngine. This allows
+ // us to pass a "loc" instead of an "SVal" for "Array".
if (Array.isUnknownOrUndef())
return Array;
@@ -437,7 +473,14 @@
if (Ta == Tb)
return CastResult(state, R);
}
-
+
+ // FIXME: We should handle the case when we are casting *back* to a
+ // previous type. For example:
+ //
+ // void* x = ...;
+ // char* y = (char*) x;
+ // void* z = (void*) y; // <-- we should get the same region that is
+ // bound to 'x'
const MemRegion* ViewR = MRMgr.getAnonTypedRegion(CastToTy, R);
return CastResult(AddRegionView(state, ViewR, R), ViewR);
}
@@ -446,18 +489,37 @@
assert(!isa<UnknownVal>(L) && "location unknown");
assert(!isa<UndefinedVal>(L) && "location undefined");
+ // FIXME: What does loc::SymbolVal represent? It represents the value
+ // of a location but that value is not known. In the future we should
+ // handle potential aliasing relationships; e.g. a loc::SymbolVal could
+ // be an alias for a particular region.
if (isa<loc::SymbolVal>(L))
return UnknownVal();
+ // FIXME: Is this even possible? Shouldn't this be treated as a null
+ // dereference at a higher level?
if (isa<loc::ConcreteInt>(L))
return UndefinedVal();
+ // FIXME: Should this be refactored into GRExprEngine or GRStateManager?
+ // It seems that all StoreManagers would do the same thing here.
if (isa<loc::FuncVal>(L))
return L;
+ // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
+ // instead of 'Loc', and have the other Loc cases handled at a higher level.
const MemRegion* R = cast<loc::MemRegionVal>(L).getRegion();
assert(R && "bad region");
+ // FIXME: We should eventually handle funny addressing. e.g.:
+ //
+ // int x = ...;
+ // int *p = &x;
+ // char *q = (char*) p;
+ // char c = *q; // returns the first byte of 'x'.
+ //
+ // Such funny addressing will occur due to layering of regions.
+
if (const TypedRegion* TR = dyn_cast<TypedRegion>(R))
if (TR->getRValueType(getContext())->isStructureType())
return RetrieveStruct(St, TR);
@@ -468,25 +530,40 @@
// Check if the region has a binding.
if (V)
return *V;
+
+ GRStateRef state(St, StateMgr);
+ // FIXME: Do we even need a killset? If 'Unknown' is explicitly
+ // bound to to a region won't this be enough? (that's basically
+ // what a killset is). RemoveDeadBindings should only remove
+ // bindings that are no longer accessible, which means that won't
+ // ever be read.
+
// Check if the region is in killset.
- GRStateRef state(St, StateMgr);
if (state.contains<RegionKills>(R))
return UnknownVal();
- // The location is not initialized.
-
- // We treat parameters as symbolic values.
+ // The location does not have a bound value. This means that it has
+ // the value it had upon its creation and/or entry to the analyzed
+ // function/method. These are either symbolic values or 'undefined'.
+
+ // We treat function parameters as symbolic values.
if (const VarRegion* VR = dyn_cast<VarRegion>(R))
if (isa<ParmVarDecl>(VR->getDecl()))
return SVal::MakeSymbolValue(getSymbolManager(), VR,
VR->getRValueType(getContext()));
- if (MRMgr.onStack(R) || MRMgr.onHeap(R))
+ if (MRMgr.onStack(R) || MRMgr.onHeap(R)) {
+ // All stack variables are considered to have undefined values
+ // upon creation. All heap allocated blocks are considered to
+ // have undefined values as well unless they are explicitly bound
+ // to specific values.
return UndefinedVal();
- else
- return SVal::MakeSymbolValue(getSymbolManager(), R,
- cast<TypedRegion>(R)->getRValueType(getContext()));
+ }
+
+ // All other values are symbolic.
+ return SVal::MakeSymbolValue(getSymbolManager(), R,
+ cast<TypedRegion>(R)->getRValueType(getContext()));
// FIXME: consider default values for elements and fields.
}
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