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path: root/clang/lib/StaticAnalyzer/Checkers/CloneChecker.cpp
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* [analyzer] Increase minimum complexity filter of the CloneChecker.Raphael Isemann2017-09-041-1/+1
| | | | | | | | | | | | | | | Summary: So far we used a value of 10 which was useful for testing but produces many false-positives in real programs. The usual suspicious clones we find seem to be at around a complexity value of 70 and for normal clone-reporting everything above 50 seems to be a valid normal clone for users, so let's just go with 50 for now and set this as the new default value. This patch also explicitly sets the complexity value for the regression tests as they serve more of a regression testing/debugging purpose and shouldn't really be reported by default in real programs. I'll add more tests that reflect actual found bugs that then need to pass with the default setting in the future. Reviewers: NoQ Subscribers: cfe-commits, javed.absar, xazax.hun, v.g.vassilev Differential Revision: https://reviews.llvm.org/D34178 llvm-svn: 312468
* [analyzer] Performance optimizations for the CloneCheckerRaphael Isemann2017-08-311-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This patch aims at optimizing the CloneChecker for larger programs. Before this patch we took around 102 seconds to analyze sqlite3 with a complexity value of 50. After this patch we now take 2.1 seconds to analyze sqlite3. The biggest performance optimization is that we now put the constraint for group size before the constraint for the complexity. The group size constraint is much faster in comparison to the complexity constraint as it only does a simple integer comparison. The complexity constraint on the other hand actually traverses each Stmt and even checks the macro stack, so it is obviously not able to handle larger amounts of incoming clones. The new order filters out all the single-clone groups that the type II constraint generates in a faster way before passing the fewer remaining clones to the complexity constraint. This reduced runtime by around 95%. The other change is that we also delay the verification part of the type II clones back in the chain of constraints. This required to split up the constraint into two parts - a verification and a hash constraint (which is also making it more similar to the original design of the clone detection algorithm). The reasoning for this is the same as before: The verification constraint has to traverse many statements and shouldn't be at the start of the constraint chain. However, as the type II hashing has to be the first step in our algorithm, we have no other choice but split this constrain into two different ones. Now our group size and complexity constrains filter out a chunk of the clones before they reach the slow verification step, which reduces the runtime by around 8%. I also kept the full type II constraint around - that now just calls it's two sub-constraints - in case someone doesn't care about the performance benefits of doing this. Reviewers: NoQ Reviewed By: NoQ Subscribers: klimek, v.g.vassilev, xazax.hun, cfe-commits Differential Revision: https://reviews.llvm.org/D34182 llvm-svn: 312222
* [analyzer] Teach CloneDetection about Qt Meta-Object Compiler to filter auto ↵Leslie Zhai2017-06-201-1/+1
| | | | | | | | | | | | generated files Reviewers: v.g.vassilev, teemperor Reviewed By: teemperor Differential Revision: https://reviews.llvm.org/D34353 llvm-svn: 305774
* [analyzer] Teach CloneDetection about Qt Meta-Object CompilerLeslie Zhai2017-06-191-1/+6
| | | | | | | | | | Reviewers: v.g.vassilev, zaks.anna, NoQ, teemperor Reviewed By: v.g.vassilev, zaks.anna, NoQ, teemperor Differential Revision: https://reviews.llvm.org/D31320 llvm-svn: 305659
* [analyzer] Reland r299544 "Add a modular constraint system to the CloneDetector"Artem Dergachev2017-04-061-31/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | Hopefully fix crashes by unshadowing the variable. Original commit message: A big part of the clone detection code is functionality for filtering clones and clone groups based on different criteria. So far this filtering process was hardcoded into the CloneDetector class, which made it hard to understand and, ultimately, to extend. This patch splits the CloneDetector's logic into a sequence of reusable constraints that are used for filtering clone groups. These constraints can be turned on and off and reodreder at will, and new constraints are easy to implement if necessary. Unit tests are added for the new constraint interface. This is a refactoring patch - no functional change intended. Patch by Raphael Isemann! Differential Revision: https://reviews.llvm.org/D23418 llvm-svn: 299653
* Revert "[analyzer] Add a modular constraint system to the CloneDetector"Artem Dergachev2017-04-051-69/+31
| | | | | | | | This reverts commit r299544. Crashes on tests on some buildbots. llvm-svn: 299550
* [analyzer] Add a modular constraint system to the CloneDetectorArtem Dergachev2017-04-051-31/+69
| | | | | | | | | | | | | | | | | | | | | | A big part of the clone detection code is functionality for filtering clones and clone groups based on different criteria. So far this filtering process was hardcoded into the CloneDetector class, which made it hard to understand and, ultimately, to extend. This patch splits the CloneDetector's logic into a sequence of reusable constraints that are used for filtering clone groups. These constraints can be turned on and off and reodreder at will, and new constraints are easy to implement if necessary. Unit tests are added for the new constraint interface. This is a refactoring patch - no functional change intended. Patch by Raphael Isemann! Differential Revision: https://reviews.llvm.org/D23418 llvm-svn: 299544
* [analyzer] Re-apply r283094 "Improve CloneChecker diagnostics"Artem Dergachev2016-10-081-50/+56
| | | | | | The parent commit (r283092) was reverted before and now finally landed. llvm-svn: 283661
* Revert "[analyzer] Improve CloneChecker diagnostics" as its depends on ↵Vitaly Buka2016-10-041-56/+50
| | | | | | | | reverted r283092 This reverts commit r283094. llvm-svn: 283182
* [analyzer] Improve CloneChecker diagnosticsArtem Dergachev2016-10-031-50/+56
| | | | | | | | | | | | | | | | | | Highlight code clones referenced by the warning message with the help of the extra notes feature recently introduced in r283092. Change warning text to more clang-ish. Remove suggestions from the copy-paste error checker diagnostics, because currently our suggestions are strictly 50% wrong (we do not know which of the two code clones contains the error), and for that reason we should not sound as if we're actually suggesting this. Hopefully a better solution would bring them back. Make sure the suspicious clone pair structure always mentions the correct variable for the second clone. Differential Revision: https://reviews.llvm.org/D24916 llvm-svn: 283094
* [analyzer] Use faster hashing (MD5) in CloneDetector.Artem Dergachev2016-08-201-9/+0
| | | | | | | | | | | | | | | This replaces the old approach of fingerprinting every AST node into a string, which avoided collisions and was simple to implement, but turned out to be extremely ineffective with respect to both performance and memory. The collisions are now dealt with in a separate pass, which no longer causes performance problems because collisions are rare. Patch by Raphael Isemann! Differential Revision: https://reviews.llvm.org/D22515 llvm-svn: 279378
* [analyzer] Teach CloneDetector to find clones that look like copy-paste errors.Artem Dergachev2016-08-181-2/+70
| | | | | | | | | | | | | | | | | | | The original clone checker tries to find copy-pasted code that is exactly identical to the original code, up to minor details. As an example, if the copy-pasted code has all references to variable 'a' replaced with references to variable 'b', it is still considered to be an exact clone. The new check finds copy-pasted code in which exactly one variable seems out of place compared to the original code, which likely indicates a copy-paste error (a variable was forgotten to be renamed in one place). Patch by Raphael Isemann! Differential Revision: https://reviews.llvm.org/D23314 llvm-svn: 279056
* [analyzer] Hotfix for build failure due to declaration shadowing in r276782.Artem Dergachev2016-07-261-3/+3
| | | | | | | CloneDetector member variable is shadowing the class with the same name, which causes build failures on some platforms. llvm-svn: 276791
* [analyzer] Add basic capabilities to detect source code clones.Artem Dergachev2016-07-261-0/+96
This patch adds the CloneDetector class which allows searching source code for clones. For every statement or group of statements within a compound statement, CloneDetector computes a hash value, and finds clones by detecting identical hash values. This initial patch only provides a simple hashing mechanism that hashes the kind of each sub-statement. This patch also adds CloneChecker - a simple static analyzer checker that uses CloneDetector to report copy-pasted code. Patch by Raphael Isemann! Differential Revision: https://reviews.llvm.org/D20795 llvm-svn: 276782
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