Commit Graph

7 Commits

Author SHA1 Message Date
Artem Dergachev 4eca0de7b7 [analyzer] Re-apply r283094 "Improve CloneChecker diagnostics"
The parent commit (r283092) was reverted before and now finally landed.

llvm-svn: 283661
2016-10-08 10:54:30 +00:00
Vitaly Buka 1a8d52d1ae Revert "[analyzer] Improve CloneChecker diagnostics" as its depends on reverted r283092
This reverts commit r283094.

llvm-svn: 283182
2016-10-04 02:40:35 +00:00
Artem Dergachev c87d2a613e [analyzer] Improve CloneChecker diagnostics
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
2016-10-03 08:11:50 +00:00
Artem Dergachev 5657486854 [analyzer] Use faster hashing (MD5) in CloneDetector.
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
2016-08-20 17:35:53 +00:00
Artem Dergachev 2fc1985db3 [analyzer] Teach CloneDetector to find clones that look like copy-paste errors.
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
2016-08-18 12:29:41 +00:00
Artem Dergachev 96034ca10e [analyzer] Hotfix for build failure due to declaration shadowing in r276782.
CloneDetector member variable is shadowing the class with the same name,
which causes build failures on some platforms.

llvm-svn: 276791
2016-07-26 19:05:22 +00:00
Artem Dergachev ba816326f3 [analyzer] Add basic capabilities to detect source code clones.
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
2016-07-26 18:13:12 +00:00