PR16054: Slight strengthening for -Wsometimes-uninitialized: if we use a
variable uninitialized every time we reach its (reachable) declaration, or
every time we call the surrounding function, promote the warning from
-Wmaybe-uninitialized to -Wsometimes-uninitialized.
This is still slightly weaker than desired: we should, in general, warn
if a use is uninitialized the first time it is evaluated.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@190623 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/UninitializedValues.cpp b/lib/Analysis/UninitializedValues.cpp
index 6c6804f..332c02c 100644
--- a/lib/Analysis/UninitializedValues.cpp
+++ b/lib/Analysis/UninitializedValues.cpp
@@ -527,12 +527,28 @@
SuccsVisited[block->getBlockID()] = block->succ_size();
while (!Queue.empty()) {
const CFGBlock *B = Queue.pop_back_val();
+
+ // If the use is always reached from the entry block, make a note of that.
+ if (B == &cfg.getEntry())
+ Use.setUninitAfterCall();
+
for (CFGBlock::const_pred_iterator I = B->pred_begin(), E = B->pred_end();
I != E; ++I) {
const CFGBlock *Pred = *I;
- if (vals.getValue(Pred, B, vd) == Initialized)
+ Value AtPredExit = vals.getValue(Pred, B, vd);
+ if (AtPredExit == Initialized)
// This block initializes the variable.
continue;
+ if (AtPredExit == MayUninitialized &&
+ vals.getValue(B, 0, vd) == Uninitialized) {
+ // This block declares the variable (uninitialized), and is reachable
+ // from a block that initializes the variable. We can't guarantee to
+ // give an earlier location for the diagnostic (and it appears that
+ // this code is intended to be reachable) so give a diagnostic here
+ // and go no further down this path.
+ Use.setUninitAfterDecl();
+ continue;
+ }
unsigned &SV = SuccsVisited[Pred->getBlockID()];
if (!SV) {