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Merge pull request #6745 from andersfugmann/handle_overflow_for_upperbound

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C++: Handle overflow for upperbound
This commit is contained in:
Jonas Jensen
2021-09-27 10:32:49 +02:00
committed by GitHub
parent 8debae1a3b aebde189f8
commit 06b36f742e
4 changed files with 19 additions and 1 deletions
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3
cpp/ql/lib/semmle/code/cpp/rangeanalysis/SimpleRangeAnalysis.qll
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@@ -1549,7 +1549,8 @@ private float getGuardedUpperBound(VariableAccess guardedAccess) {
// that there is one predecessor, albeit somewhat conservative.
exists(unique(BasicBlock b | b = def.(BasicBlock).getAPredecessor())) and
guardedAccess = def.getAUse(v) and
result = max(float ub | upperBoundFromGuard(guard, guardVa, ub, branch))
result = max(float ub | upperBoundFromGuard(guard, guardVa, ub, branch)) and
not convertedExprMightOverflow(guard.getAChild+())
)
}

4
cpp/ql/test/library-tests/rangeanalysis/SimpleRangeAnalysis/lowerBound.expected
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@@ -599,6 +599,10 @@
| test.c:675:7:675:7 | y | -2147483648 |
| test.c:684:7:684:7 | x | -2147483648 |
| test.c:689:7:689:7 | x | -2147483648 |
| test.c:696:8:696:8 | x | 2147483647 |
| test.c:696:12:696:12 | y | 256 |
| test.c:697:9:697:9 | x | 2147483647 |
| test.c:698:9:698:9 | y | 256 |
| test.cpp:10:7:10:7 | b | -2147483648 |
| test.cpp:11:5:11:5 | x | -2147483648 |
| test.cpp:13:10:13:10 | x | -2147483648 |

9
cpp/ql/test/library-tests/rangeanalysis/SimpleRangeAnalysis/test.c
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@@ -689,3 +689,12 @@ label:
out(x);
goto label;
}
void test_overflow() {
const int x = 2147483647; // 2^31-1
const int y = 256;
if ((x + y) <= 512) {
out(x);
out(y);
}
}

4
cpp/ql/test/library-tests/rangeanalysis/SimpleRangeAnalysis/upperBound.expected
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@@ -599,6 +599,10 @@
| test.c:675:7:675:7 | y | 2147483647 |
| test.c:684:7:684:7 | x | 2147483647 |
| test.c:689:7:689:7 | x | 15 |
| test.c:696:8:696:8 | x | 2147483647 |
| test.c:696:12:696:12 | y | 256 |
| test.c:697:9:697:9 | x | 2147483647 |
| test.c:698:9:698:9 | y | 256 |
| test.cpp:10:7:10:7 | b | 2147483647 |
| test.cpp:11:5:11:5 | x | 2147483647 |
| test.cpp:13:10:13:10 | x | 2147483647 |