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Reset killed bounds for in-scope variables only #926

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Merged
merged 2 commits into from
Oct 23, 2020
Merged

Reset killed bounds for in-scope variables only #926

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4700203
Only reset variables in scope at S to normalized declared bounds
Oct 22, 2020
4712aa6
Add test for out-of-scope killed variable
Oct 22, 2020
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9 changes: 6 additions & 3 deletions clang/lib/Sema/SemaBounds.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2266,10 +2266,13 @@ namespace {

// KilledBounds stores a mapping of statements to all variables whose
// bounds are killed by each statement. Here we reset the bounds of all
// variables killed by the statement S to the normalized declared bounds.
// variables that are in scope at the statement S and whose bounds are
// killed by S to the normalized declared bounds.
for (const VarDecl *V : I->second) {
if (BoundsExpr *Bounds = S.NormalizeBounds(V))
State.ObservedBounds[V] = Bounds;
if (State.ObservedBounds.find(V) != State.ObservedBounds.end()) {
if (BoundsExpr *Bounds = S.NormalizeBounds(V))
State.ObservedBounds[V] = Bounds;
}
}
}

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28 changes: 28 additions & 0 deletions clang/test/CheckedC/inferred-bounds/widened-bounds.c
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Expand Up @@ -1266,3 +1266,31 @@ void f34(_Nt_array_ptr<char> p : count(i), int i, int flag) {
// CHECK: 2: *(p + i + 1)
// CHECK: upper_bound(p) = 1
}

void f35(void) {
int i, j;
for (;;) {
i = 1;
j = 2;
_Nt_array_ptr<char> p : count(i + j) = 0;
if (p[i + j]) {
return;
}
}

// CHECK: In function: f35
// CHECK: [B5]
// CHECK: 1: int i;
// CHECK: 2: int j;
// CHECK: [B4]
// CHECK: T: for (; ; )
// CHECK: [B3]
// CHECK: 1: i = 1
// CHECK: 2: j = 2
// CHECK: 3: _Nt_array_ptr<char> p : count(i + j) = 0;
// CHECK: 4: p[i + j] (ImplicitCastExpr, LValueToRValue, char)
// CHECK: T: if [B3.4]
// CHECK: [B2]
// CHECK: 1: return;
// CHECK: upper_bound(p) = 1
}