[cfe-commits] r139027 - in /cfe/trunk: lib/Analysis/UninitializedValues.cpp test/Sema/uninit-variables.c
Ted Kremenek
kremenek at apple.com
Fri Sep 2 12:39:27 PDT 2011
Author: kremenek
Date: Fri Sep 2 14:39:26 2011
New Revision: 139027
URL: http://llvm.org/viewvc/llvm-project?rev=139027&view=rev
Log:
-Wuninitialized: fix insidious bug resulting from interplay of blocks and dead code. Fixes <rdar://problem/10060250>.
Modified:
cfe/trunk/lib/Analysis/UninitializedValues.cpp
cfe/trunk/test/Sema/uninit-variables.c
Modified: cfe/trunk/lib/Analysis/UninitializedValues.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/UninitializedValues.cpp?rev=139027&r1=139026&r2=139027&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/UninitializedValues.cpp (original)
+++ cfe/trunk/lib/Analysis/UninitializedValues.cpp Fri Sep 2 14:39:26 2011
@@ -330,7 +330,6 @@
const CFG &cfg;
AnalysisContext ∾
UninitVariablesHandler *handler;
- const bool flagBlockUses;
/// The last DeclRefExpr seen when analyzing a block. Used to
/// cheat when detecting cases when the address of a variable is taken.
@@ -349,10 +348,9 @@
public:
TransferFunctions(CFGBlockValues &vals, const CFG &cfg,
AnalysisContext &ac,
- UninitVariablesHandler *handler,
- bool flagBlockUses)
+ UninitVariablesHandler *handler)
: vals(vals), cfg(cfg), ac(ac), handler(handler),
- flagBlockUses(flagBlockUses), lastDR(0), lastLoad(0),
+ lastDR(0), lastLoad(0),
skipProcessUses(false) {}
void reportUninit(const DeclRefExpr *ex, const VarDecl *vd,
@@ -424,14 +422,10 @@
}
void TransferFunctions::VisitBlockExpr(BlockExpr *be) {
- if (!flagBlockUses || !handler)
- return;
const BlockDecl *bd = be->getBlockDecl();
for (BlockDecl::capture_const_iterator i = bd->capture_begin(),
e = bd->capture_end() ; i != e; ++i) {
const VarDecl *vd = i->getVariable();
- if (!vd->hasLocalStorage())
- continue;
if (!isTrackedVar(vd))
continue;
if (i->isByRef()) {
@@ -439,7 +433,7 @@
continue;
}
Value v = vals[vd];
- if (isUninitialized(v))
+ if (handler && isUninitialized(v))
handler->handleUseOfUninitVariable(be, vd, isAlwaysUninit(v));
}
}
@@ -610,8 +604,7 @@
static bool runOnBlock(const CFGBlock *block, const CFG &cfg,
AnalysisContext &ac, CFGBlockValues &vals,
llvm::BitVector &wasAnalyzed,
- UninitVariablesHandler *handler = 0,
- bool flagBlockUses = false) {
+ UninitVariablesHandler *handler = 0) {
wasAnalyzed[block->getBlockID()] = true;
@@ -645,11 +638,14 @@
bool isFirst = true;
for (CFGBlock::const_pred_iterator I = block->pred_begin(),
E = block->pred_end(); I != E; ++I) {
- vals.mergeIntoScratch(vals.getValueVector(*I, block), isFirst);
- isFirst = false;
+ const CFGBlock *pred = *I;
+ if (wasAnalyzed[pred->getBlockID()]) {
+ vals.mergeIntoScratch(vals.getValueVector(pred, block), isFirst);
+ isFirst = false;
+ }
}
// Apply the transfer function.
- TransferFunctions tf(vals, cfg, ac, handler, flagBlockUses);
+ TransferFunctions tf(vals, cfg, ac, handler);
for (CFGBlock::const_iterator I = block->begin(), E = block->end();
I != E; ++I) {
if (const CFGStmt *cs = dyn_cast<CFGStmt>(&*I)) {
@@ -691,6 +687,7 @@
llvm::BitVector previouslyVisited(cfg.getNumBlockIDs());
worklist.enqueueSuccessors(&cfg.getEntry());
llvm::BitVector wasAnalyzed(cfg.getNumBlockIDs(), false);
+ wasAnalyzed[cfg.getEntry().getBlockID()] = true;
while (const CFGBlock *block = worklist.dequeue()) {
// Did the block change?
@@ -703,9 +700,9 @@
// Run through the blocks one more time, and report uninitialized variabes.
for (CFG::const_iterator BI = cfg.begin(), BE = cfg.end(); BI != BE; ++BI) {
- if (wasAnalyzed[(*BI)->getBlockID()]) {
- runOnBlock(*BI, cfg, ac, vals, wasAnalyzed, &handler,
- /* flagBlockUses */ true);
+ const CFGBlock *block = *BI;
+ if (wasAnalyzed[block->getBlockID()]) {
+ runOnBlock(block, cfg, ac, vals, wasAnalyzed, &handler);
++stats.NumBlockVisits;
}
}
Modified: cfe/trunk/test/Sema/uninit-variables.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/uninit-variables.c?rev=139027&r1=139026&r2=139027&view=diff
==============================================================================
--- cfe/trunk/test/Sema/uninit-variables.c (original)
+++ cfe/trunk/test/Sema/uninit-variables.c Fri Sep 2 14:39:26 2011
@@ -381,3 +381,13 @@
double (*memory)[2][x] = malloc(sizeof(*memory)); // no-warning
}
+// Test absurd case of deadcode + use of blocks. This previously was a false positive
+// due to an analysis bug.
+int test_block_and_dead_code() {
+ __block int x;
+ ^{ x = 1; }();
+ if (0)
+ return x;
+ return x; // no-warning
+}
+
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