[PATCH] D13126: New static analyzer checker for loss of sign/precision

[Daniel Marjamäki via cfe-commits]

danielmarjamaki updated this revision to Diff 40505.
danielmarjamaki added a comment.

I have problems with the "default" handling of expressions.

I want to warn about loss of precision for such code:

  unsigned int x = 256;
  unsigned char c;
  c = x;

The analyser tells me that the RHS value is 0 instead of 256 in the assignment "c = x". Here is the dump of the ProgramState:

Store (direct and default bindings), 0x0 :

Expressions:
 (0x7b9bd30,0x7b458d8) c : &c
 (0x7b9bd30,0x7b45940) x : 0 U8b
Ranges are empty.

This patch is a quick proof-of-concept where I track variable values myself using ProgramState. It gives me better results when I scan projects.

I wonder if you think I should continue working on this proof-of-concept method. Or if you have some tip how I can see the untruncated rhs value in a assignment.


http://reviews.llvm.org/D13126

Files:
  lib/StaticAnalyzer/Checkers/CMakeLists.txt
  lib/StaticAnalyzer/Checkers/Checkers.td
  lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
  test/Analysis/conversion.c

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