C++: Improvements to "Declaration hides parameter"#751
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geoffw0 merged 4 commits intogithub:masterfrom Jan 11, 2019
Merged
C++: Improvements to "Declaration hides parameter"#751geoffw0 merged 4 commits intogithub:masterfrom
geoffw0 merged 4 commits intogithub:masterfrom
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Bad magic ended up in `LocalVariable.getFunction` and effectively
created a Cartesian product. Before this change, the timing looked like
this:
Variable::LocalVariable::getFunction_dispred#bb ... 50.1s
#select#cpe#123#fff ............................... 20.6s
After this change, those predicates become much faster:
Variable::LocalVariable::getFunction_dispred#ff ... 121ms
DeclarationHidesParameter::localVariableNames#fff . 77ms
#select#cpe#123#fff ............................... 28ms
Introducing the predicate `localVariableNames` ensures that we can do
the main join on two columns simultaneously, so that's a change we
should keep even if we remove the `pragma[nomagic]` later.
This change suppresses results from "Declaration hides parameter" where the ParameterDeclarationEntry does not link up to the right FunctionDeclarationEntry.
geoffw0
reviewed
Jan 11, 2019
| // We also exclude names from functions that have multiple definitions. | ||
| // This should not happen in a single application but since we | ||
| // have a system wide view it is likely to happen for instance for | ||
| // the main function. |
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The forum post https://discuss.lgtm.com/t/please-help-me-understand-this-issue-local-variable-buffer-hides-a-parameter-of-the-same-name/1662 prompted me to look at this query. I auto-formatted the query and fixed a performance bug, and then I worked around the issue that was causing false positives. I think it's an extractor bug, and I've filed CPP-331 to track it.
I wasn't able to create a unit test that demonstrates the problem, but you can see how the results change on the jx_application_framework project: before and after.