[cfe-commits] r42067 - in /cfe/trunk/Analysis: DataflowSolver.h UninitializedValues.cpp
Ted Kremenek
kremenek at apple.com
Mon Sep 17 14:59:09 PDT 2007
Author: kremenek
Date: Mon Sep 17 16:59:08 2007
New Revision: 42067
URL: http://llvm.org/viewvc/llvm-project?rev=42067&view=rev
Log:
Bug fix to merging of data flow values (merge incorrectly made values
too "conservative").
Several revisions to UninitializedValues checker after testing. We
now appear to be working correctly (probably some bugs still, but main
functionality appears to be there). Implemented careful emitting of
warnings so that we wouldn't get a cascade of warnings for simply not
defining a single variable and using it everywhere. This way the
warnings point closer to the root cause rather than "symptoms" from
using values derived from uninitialized variables.
Modified:
cfe/trunk/Analysis/DataflowSolver.h
cfe/trunk/Analysis/UninitializedValues.cpp
Modified: cfe/trunk/Analysis/DataflowSolver.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/Analysis/DataflowSolver.h?rev=42067&r1=42066&r2=42067&view=diff
==============================================================================
--- cfe/trunk/Analysis/DataflowSolver.h (original)
+++ cfe/trunk/Analysis/DataflowSolver.h Mon Sep 17 16:59:08 2007
@@ -85,6 +85,9 @@
/// only be used for querying the dataflow values within a block with
/// and Observer object.
void runOnBlock(const CFGBlock* B) {
+ if (D.getBlockDataMap().find(B) == D.getBlockDataMap().end())
+ return;
+
TransferFuncsTy TF (D.getAnalysisData());
ProcessBlock(B,TF,AnalysisDirTag());
}
@@ -118,14 +121,6 @@
I != E; ++I)
WorkList.enqueue(*I);
}
-
- // For blocks that have no associated dataflow value, instantiate a
- // default value.
- BlockDataMapTy& M = D.getBlockDataMap();
-
- for (CFG::const_iterator I=cfg.begin(), E=cfg.end(); I!=E; ++I)
- if (M.find(&*I) == M.end())
- M[&*I].resetValues(D.getAnalysisData());
}
/// SolveDataflowEquations (BACKWARD ANALYSIS) - Perform the actual
@@ -155,7 +150,7 @@
/// ProcessBlock (FORWARD ANALYSIS) - Process the transfer functions
/// for a given block based on a forward analysis.
- bool ProcessBlock(const CFGBlock* B, TransferFuncsTy& TF,
+ bool ProcessBlock(const CFGBlock* B, TransferFuncsTy& TF,
dataflow::forward_analysis_tag) {
ValTy& V = TF.getVal();
@@ -164,9 +159,21 @@
V.resetValues(D.getAnalysisData());
MergeOperatorTy Merge;
+ BlockDataMapTy& M = D.getBlockDataMap();
+ bool firstMerge = true;
+
for (CFGBlock::const_pred_iterator I=B->pred_begin(),
- E=B->pred_end(); I!=E; ++I)
- Merge(V,D.getBlockData(*I));
+ E=B->pred_end(); I!=E; ++I) {
+ typename BlockDataMapTy::iterator BI = M.find(*I);
+ if (BI != M.end()) {
+ if (firstMerge) {
+ firstMerge = false;
+ V.copyValues(BI->second);
+ }
+ else
+ Merge(V,BI->second);
+ }
+ }
// Process the statements in the block in the forward direction.
for (CFGBlock::const_iterator I=B->begin(), E=B->end(); I!=E; ++I)
@@ -186,9 +193,21 @@
V.resetValues(D.getAnalysisData());
MergeOperatorTy Merge;
+ BlockDataMapTy& M = D.getBlockDataMap();
+ bool firstMerge = true;
+
for (CFGBlock::const_succ_iterator I=B->succ_begin(),
- E=B->succ_end(); I!=E; ++I)
- Merge(V,D.getBlockData(*I));
+ E=B->succ_end(); I!=E; ++I) {
+ typename BlockDataMapTy::iterator BI = M.find(*I);
+ if (BI != M.end()) {
+ if (firstMerge) {
+ firstMerge = false;
+ V.copyValues(BI->second);
+ }
+ else
+ Merge(V,BI->second);
+ }
+ }
// Process the statements in the block in the forward direction.
for (CFGBlock::const_reverse_iterator I=B->begin(), E=B->end(); I!=E; ++I)
Modified: cfe/trunk/Analysis/UninitializedValues.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/Analysis/UninitializedValues.cpp?rev=42067&r1=42066&r2=42067&view=diff
==============================================================================
--- cfe/trunk/Analysis/UninitializedValues.cpp (original)
+++ cfe/trunk/Analysis/UninitializedValues.cpp Mon Sep 17 16:59:08 2007
@@ -75,8 +75,8 @@
R.BlockStmt_Visit(*BI);
// Initialize the values of the last block.
- UninitializedValues::ValTy& V = getBlockDataMap()[&cfg.getEntry()];
- V.resetValues(getAnalysisData());
+// UninitializedValues::ValTy& V = getBlockDataMap()[&cfg.getEntry()];
+// V.resetValues(getAnalysisData());
}
//===----------------------------------------------------------------------===//
@@ -88,8 +88,11 @@
class TransferFuncs : public CFGStmtVisitor<TransferFuncs,bool> {
UninitializedValues::ValTy V;
UninitializedValues::AnalysisDataTy& AD;
+ bool InitWithAssigns;
public:
- TransferFuncs(UninitializedValues::AnalysisDataTy& ad) : AD(ad) {
+ TransferFuncs(UninitializedValues::AnalysisDataTy& ad,
+ bool init_with_assigns=true) :
+ AD(ad), InitWithAssigns(init_with_assigns) {
V.resetValues(AD);
}
@@ -134,9 +137,21 @@
else if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(S))
if (BlockVarDecl* VD = dyn_cast<BlockVarDecl>(DR->getDecl())) {
assert ( AD.VMap.find(VD) != AD.VMap.end() && "Unknown VarDecl.");
- return V.DeclBV[ AD.VMap[VD] ] = Visit(B->getRHS());
+
+ if(InitWithAssigns) {
+ // Pseudo-hack to prevent cascade of warnings. If the RHS uses
+ // an uninitialized value, then we are already going to flag a warning
+ // related to the "cause". Thus, propogating uninitialized doesn't
+ // make sense, since we are just adding extra messages that don't
+ // contribute to diagnosing the bug. In InitWithAssigns mode
+ // we unconditionally set the assigned variable to Initialized to
+ // prevent Uninitialized propogation.
+ return V.DeclBV[AD.VMap[VD]] = Initialized();
+ }
+ else
+ return V.DeclBV[ AD.VMap[VD] ] = Visit(B->getRHS());
}
-
+
break;
}
}
@@ -154,7 +169,8 @@
AD.EMap.end() && "Unknown Expr.");
assert ( AD.VMap.find(VD) != AD.VMap.end() && "Unknown VarDecl.");
- x = V.DeclBV[ AD.VMap[VD] ] = V.ExprBV[ AD.EMap[cast<Expr>(I)] ];
+ x = V.ExprBV[ AD.EMap[cast<Expr>(I)] ];
+ V.DeclBV[ AD.VMap[VD] ] = x;
}
return x;
@@ -246,7 +262,7 @@
assert (Dst.ExprBV.size() == Src.ExprBV.size()
&& "Bitvector sizes do not match.");
- Dst.ExprBV |= Src.ExprBV;
+ Dst.ExprBV &= Src.ExprBV;
}
};
} // end anonymous namespace
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