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C++: Fix SimpleRangeAnalysis for AssignOperation

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The range analysis wasn't producing useful bounds for `AssignOperation`s
(`+=`, `-=`) unless their RHS involved a variable. This is because a
shortcut was made in the `analyzableDef` predicate, which used to
specify that an analyzable definition was one for which we'd specified
the dependencies. But we can't distinguish between having _no
dependencies_ and having _no specification of the dependencies_.

The fix is to be more explicit about which definitions are analyzable.
To avoid too much repetition I'm still calling out to `analyzableExpr`
in the new code.
This commit is contained in:
Jonas Jensen
2020-08-14 14:05:27 +02:00
parent 8cbd4974ae
commit f90d779122
4 changed files with 19 additions and 11 deletions
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8
cpp/ql/test/library-tests/rangeanalysis/SimpleRangeAnalysis/lowerBound.expected
View File

@@ -427,10 +427,10 @@
| test.c:408:7:408:7 | i | 10 |
| test.c:410:3:410:3 | i | -2147483648 |
| test.c:411:3:411:3 | i | 10 |
| test.c:412:7:412:7 | i | -2147483648 |
| test.c:412:7:412:7 | i | 20 |
| test.c:414:3:414:3 | i | -2147483648 |
| test.c:415:3:415:3 | i | 40 |
| test.c:416:7:416:7 | i | -2147483648 |
| test.c:416:7:416:7 | i | 30 |
| test.c:418:3:418:3 | i | -2147483648 |
| test.c:418:7:418:7 | j | -2147483648 |
| test.c:419:7:419:7 | i | 40 |
@@ -438,8 +438,8 @@
| test.c:421:8:421:8 | j | 40 |
| test.c:422:7:422:7 | i | 50 |
| test.c:424:3:424:3 | i | -2147483648 |
| test.c:424:13:424:13 | j | -2147483648 |
| test.c:425:7:425:7 | i | -2147483648 |
| test.c:424:13:424:13 | j | 50 |
| test.c:425:7:425:7 | i | 60 |
| test.c:432:12:432:12 | a | 0 |
| test.c:432:17:432:17 | a | 3 |
| test.c:432:33:432:33 | b | 0 |

2
cpp/ql/test/library-tests/rangeanalysis/SimpleRangeAnalysis/test.c
View File

@@ -422,7 +422,7 @@ void test17() {
out(i); // 50
i = 20 + (j -= 10);
out(i); // 60 [BUG: the analysis thinks it's 2^-31 .. 2^31-1]
out(i); // 60
}
// Tests for unsigned multiplication.

8
cpp/ql/test/library-tests/rangeanalysis/SimpleRangeAnalysis/upperBound.expected
View File

@@ -427,10 +427,10 @@
| test.c:408:7:408:7 | i | 10 |
| test.c:410:3:410:3 | i | 2147483647 |
| test.c:411:3:411:3 | i | 10 |
| test.c:412:7:412:7 | i | 2147483647 |
| test.c:412:7:412:7 | i | 20 |
| test.c:414:3:414:3 | i | 2147483647 |
| test.c:415:3:415:3 | i | 40 |
| test.c:416:7:416:7 | i | 2147483647 |
| test.c:416:7:416:7 | i | 30 |
| test.c:418:3:418:3 | i | 2147483647 |
| test.c:418:7:418:7 | j | 2147483647 |
| test.c:419:7:419:7 | i | 40 |
@@ -438,8 +438,8 @@
| test.c:421:8:421:8 | j | 40 |
| test.c:422:7:422:7 | i | 50 |
| test.c:424:3:424:3 | i | 2147483647 |
| test.c:424:13:424:13 | j | 2147483647 |
| test.c:425:7:425:7 | i | 2147483647 |
| test.c:424:13:424:13 | j | 50 |
| test.c:425:7:425:7 | i | 60 |
| test.c:432:12:432:12 | a | 4294967295 |
| test.c:432:17:432:17 | a | 4294967295 |
| test.c:432:33:432:33 | b | 4294967295 |