Commit Graph

34 Commits

Author SHA1 Message Date
Valeriy Savchenko 73c120a989 [analyzer] Introduce reasoning about symbolic remainder operator
Summary:
New logic tries to narrow possible result values of the remainder operation
based on its operands and their ranges.  It also tries to be conservative
with negative operands because according to the standard the sign of
the result is implementation-defined.

rdar://problem/44978988

Differential Revision: https://reviews.llvm.org/D80117
2020-05-28 18:56:38 +03:00
Valeriy Savchenko 2a09daff0f [analyzer] Generalize bitwise AND rules for ranges
Summary:
Previously the current solver started reasoning about bitwise AND
expressions only when one of the operands is a constant.  However,
very similar logic could be applied to ranges.  This commit addresses
this shortcoming.  Additionally, it refines how we deal with negative
operands.

rdar://problem/54359410

Differential Revision: https://reviews.llvm.org/D79434
2020-05-28 18:55:49 +03:00
Valeriy Savchenko 47c4b8bd68 [analyzer] Generalize bitwise OR rules for ranges
Summary:
Previously the current solver started reasoning about bitwise OR
expressions only when one of the operands is a constant.  However,
very similar logic could be applied to ranges.  This commit addresses
this shortcoming.  Additionally, it refines how we deal with negative
operands.

Differential Revision: https://reviews.llvm.org/D79336
2020-05-28 18:55:22 +03:00
Valeriy Savchenko 1f57d76a8d [analyzer] Refactor range inference for symbolic expressions
Summary:
This change introduces a new component to unite all of the reasoning
we have about operations on ranges in the analyzer's solver.
In many cases, we might conclude that the range for a symbolic operation
is much more narrow than the type implies.  While reasoning about
runtime conditions (especially in loops), we need to support more and
more of those little pieces of logic.  The new component mostly plays
a role of an organizer for those, and allows us to focus on the actual
reasoning about ranges and not dispatching manually on the types of the
nested symbolic expressions.

Differential Revision: https://reviews.llvm.org/D79232
2020-05-28 18:54:52 +03:00
George Karpenkov a393e68b27 [analyzer] Move analyzer-eagerly-assume to AnalyzerOptions, enable by default
Differential Revision: https://reviews.llvm.org/D51251

llvm-svn: 340963
2018-08-29 20:29:17 +00:00
Vlad Tsyrklevich a7d25d5934 [Analyzer][Z3] Test fixes for Z3 constraint manager
Summary:
Since Z3 tests have been not been running [1] some tests needed to be
updated. I also added a regression test for [1].

[1] https://reviews.llvm.org/D47722

Reviewers: george.karpenkov, NoQ, ddcc

Reviewed By: george.karpenkov

Subscribers: mikhail.ramalho, dcoughlin, xazax.hun, szepet, zzheng, a.sidorin, cfe-commits

Differential Revision: https://reviews.llvm.org/D47726

llvm-svn: 334067
2018-06-06 06:25:51 +00:00
George Karpenkov bbb66ad7b2 [analyzer] assume bitwise arithmetic axioms
Patches the solver to assume that bitwise OR of an unsigned value with a
constant always produces a value larger-or-equal than the constant, and
bitwise AND with a constant always produces a value less-or-equal than
the constant.

This patch is especially useful in the context of using bitwise
arithmetic for error code encoding: the analyzer would be able to state
that the error code produced using a bitwise OR is non-zero.

Differential Revision: https://reviews.llvm.org/D39707

llvm-svn: 317820
2017-11-09 19:06:22 +00:00
Dominic Chen 184c6242fa Reland 4: [analyzer] NFC: Update test infrastructure to support multiple constraint managers
Summary: Replace calls to %clang/%clang_cc1 with %clang_analyze_cc1 when invoking static analyzer, and perform runtime substitution to select the appropriate constraint manager, per D28952.

Reviewers: xazax.hun, NoQ, zaks.anna, dcoughlin

Subscribers: mgorny, rgov, mikhail.ramalho, a.sidorin, cfe-commits

Differential Revision: https://reviews.llvm.org/D30373

llvm-svn: 296895
2017-03-03 18:02:02 +00:00
Dominic Chen 09d66f7528 Revert "Reland 3: [analyzer] NFC: Update test infrastructure to support multiple constraint managers"
This reverts commit ea36f1406e1f36bf456c3f3929839b024128e468.

llvm-svn: 296841
2017-03-02 23:30:53 +00:00
Dominic Chen feaf9ff5ee Reland 3: [analyzer] NFC: Update test infrastructure to support multiple constraint managers
Summary: Replace calls to %clang/%clang_cc1 with %clang_analyze_cc1 when invoking static analyzer, and perform runtime substitution to select the appropriate constraint manager, per D28952.

Reviewers: xazax.hun, NoQ, zaks.anna, dcoughlin

Subscribers: mgorny, rgov, mikhail.ramalho, a.sidorin, cfe-commits

Differential Revision: https://reviews.llvm.org/D30373

llvm-svn: 296837
2017-03-02 23:05:45 +00:00
Dominic Chen 4a90bf8c3f Revert "Reland 2: [analyzer] NFC: Update test infrastructure to support multiple constraint managers"
This reverts commit f93343c099fff646a2314cc7f4925833708298b1.

llvm-svn: 296836
2017-03-02 22:58:06 +00:00
Dominic Chen 1cb0256a3c Reland 2: [analyzer] NFC: Update test infrastructure to support multiple constraint managers
Summary: Replace calls to %clang/%clang_cc1 with %clang_analyze_cc1 when invoking static analyzer, and perform runtime substitution to select the appropriate constraint manager, per D28952.

Reviewers: xazax.hun, NoQ, zaks.anna, dcoughlin

Subscribers: mgorny, rgov, mikhail.ramalho, a.sidorin, cfe-commits

Differential Revision: https://reviews.llvm.org/D30373

llvm-svn: 296835
2017-03-02 22:45:24 +00:00
Dominic Chen 00355a51d0 Revert "Reland: [analyzer] NFC: Update test infrastructure to support multiple constraint managers"
This reverts commit 1b28d0b10e1c8feccb971abb6ef7a18bee589830.

llvm-svn: 296422
2017-02-28 01:50:23 +00:00
Dominic Chen 59cd893320 Reland: [analyzer] NFC: Update test infrastructure to support multiple constraint managers
Summary: Replace calls to %clang/%clang_cc1 with %clang_analyze_cc1 when invoking static analyzer, and perform runtime substitution to select the appropriate constraint manager, per D28952.

Reviewers: xazax.hun, NoQ, zaks.anna, dcoughlin

Subscribers: mgorny, rgov, mikhail.ramalho, a.sidorin, cfe-commits

Differential Revision: https://reviews.llvm.org/D30373

llvm-svn: 296414
2017-02-28 00:02:36 +00:00
Dominic Chen 8589e10c30 Revert "[analyzer] NFC: Update test infrastructure to support multiple constraint managers"
This reverts commit 8e7780b9e59ddaad1800baf533058d2c064d4787.

llvm-svn: 296317
2017-02-27 03:29:25 +00:00
Dominic Chen 02064a3076 [analyzer] NFC: Update test infrastructure to support multiple constraint managers
Summary: Replace calls to %clang/%clang_cc1 with %clang_analyze_cc1 when invoking static analyzer, and perform runtime substitution to select the appropriate constraint manager, per D28952.

Reviewers: xazax.hun, NoQ, zaks.anna, dcoughlin

Subscribers: mgorny, rgov, mikhail.ramalho, a.sidorin, cfe-commits

Differential Revision: https://reviews.llvm.org/D30373

llvm-svn: 296312
2017-02-27 02:36:15 +00:00
Jordy Rose 6d5a8caac3 [analyzer] Convert many existing tests to use clang_analyzer_eval.
llvm-svn: 156920
2012-05-16 16:01:10 +00:00
Jordy Rose 54569448f8 [analyzer] Reduce parallel code paths in SimpleSValBuilder::evalBinOpNN, and handle mixed-type operations more generally.
The logical change is that the integers in SymIntExprs may not have the same type as the symbols they are paired with. This was already the case with taint-propagation expressions created by SValBuilder::makeSymExprValNN, but I think those integers may never have been used. SimpleSValBuilder should be able to handle mixed-integer-type SymIntExprs fine now, though, and the constraint managers were already being defensive (though not entirely correct). All existing tests pass.

The logic in evalBinOpNN has been simplified so that conversion is done as late as possible. As a result, most of the switch cases have been reduced to do the minimal amount of work, delegating to another case when they can by substituting ConcreteInts and (as before) reversing the left and right arguments when useful.

Comparisons require special handling in two places (building SymIntExprs and evaluating constant-constant operations) because we don't /know/ the best type for comparing the two values. I've approximated the rules in Sema [C99 6.3.1.8]  but it'd be nice to refactor Sema's actual algorithm into ASTContext.

This is also groundwork for handling mixed-type constraints better than we do now.

llvm-svn: 156270
2012-05-06 23:40:02 +00:00
Ted Kremenek 3f955e6d89 [analyzer] rename all experimental checker packages to have 'experimental' be the common root package.
llvm-svn: 136835
2011-08-03 23:14:55 +00:00
Argyrios Kyrtzidis a9b630e4d7 Emit a -Wnull-dereference warning for "*null" not just "*null = something". Addresses rdar://9269271.
llvm-svn: 130207
2011-04-26 17:41:22 +00:00
Ted Kremenek 49c79790de Rework checker "packages" and groups to be more hierarchical.
llvm-svn: 128187
2011-03-24 00:28:47 +00:00
Argyrios Kyrtzidis 9eb02dfa89 [analyzer] Remove '-analyzer-check-objc-mem' flag, the nominee for best misnomer award.
llvm-svn: 126676
2011-02-28 19:49:42 +00:00
Argyrios Kyrtzidis 2c49ec7f1d [analyzer] Migrate NSErrorChecker and DereferenceChecker to CheckerV2.
They cooperate in that NSErrorChecker listens for ImplicitNullDerefEvent events that
DereferenceChecker can dispatch.
ImplicitNullDerefEvent is when we dereferenced a location that may be null.

llvm-svn: 126659
2011-02-28 17:36:18 +00:00
Argyrios Kyrtzidis 21c9423ef4 [analyzer] Remove '-analyzer-experimental-checks' flag.
llvm-svn: 126607
2011-02-28 01:26:43 +00:00
Argyrios Kyrtzidis b388f77ad9 [analyzer] Remove '-analyzer-experimental-internal-checks' flag, it doesn't have any checkers associated with it anymore.
llvm-svn: 126440
2011-02-24 21:43:08 +00:00
Argyrios Kyrtzidis 2d3905ffac [analyzer] Use the new registration mechanism on some of the experimental checks. These are:
CStringChecker
   ChrootChecker
   MallocChecker
   PthreadLockChecker
   StreamChecker
   UnreachableCodeChecker

MallocChecker creates implicit dependencies between checkers and needs to be handled differently.

llvm-svn: 125598
2011-02-15 21:25:03 +00:00
John McCall 57cdd88897 Do lvalue-to-rvalue conversions on the LHS of a shift operator.
Fixes rdar://problem/8776586.

llvm-svn: 121992
2010-12-16 19:28:59 +00:00
Ted Kremenek 8219b82125 Start migration of static analyzer to using the
implicit lvalue-to-rvalue casts that John McCall
recently introduced.  This causes a whole bunch
of logic in the analyzer for handling lvalues
to vanish.  It does, however, raise a few issues
in the analyzer w.r.t to modeling various constructs
(e.g., field accesses to compound literals).

The .c/.m analysis test cases that fail are
due to a missing lvalue-to-rvalue cast that
will get introduced into the AST.  The .cpp
failures were more than I could investigate in
one go, and the patch was already getting huge.
I have XFAILED some of these tests, and they
should obviously be further investigated.

Some highlights of this patch include:

- CFG no longer requires an lvalue bit for
  CFGElements
- StackFrameContext doesn't need an 'asLValue'
  flag
- The "VisitLValue" path from GRExprEngine has
  been eliminated.

Besides the test case failures (XFAILed), there
are surely other bugs that are fallout from
this change.

llvm-svn: 121960
2010-12-16 07:46:53 +00:00
Tom Care b9933f365e Added psuedo-constant analysis and integrated it into the false positive reduction stage in IdempotentOperationChecker.
- Renamed IdempotentOperationChecker::isConstant to isConstantOrPseudoConstant to better reflect the function
- Changed IdempotentOperationChecker::PreVisitBinaryOperator to only run 'CanVary' once on undefined assumptions
- Created new PsuedoConstantAnalysis class and added it to AnalysisContext
- Changed IdempotentOperationChecker to exploit the new analysis
- Updated tests with psuedo-constants
- Added check to IdempotentOperationChecker to see if a Decl is const qualified

llvm-svn: 111426
2010-08-18 21:17:24 +00:00
Tom Care 29a6250bf0 Added some false positive checking to UnreachableCodeChecker
- Allowed reporting of dead macros
- Added path walking function to search for false positives in conditional statements
- Updated some affected tests
- Added some false positive test cases

llvm-svn: 109561
2010-07-27 23:30:21 +00:00
Ted Kremenek 83b598c14f Finesse 'idempotent operations' analyzer issues to include the opcode of the binary operator for clearer error reporting. Also remove the 'Idempotent operation' prefix in messages; it's redundant since the bug type is the same.
llvm-svn: 109527
2010-07-27 18:49:08 +00:00
Tom Care 826e6b4023 Improved false positive rate for the idempotent operations checker and moved it into the default path-sensitive analysis options.
- Added checks for static local variables, self assigned parameters, and truncating/extending self assignments
- Removed command line option (now default with --analyze)
- Updated test cases to pass with idempotent operation warnings

llvm-svn: 108550
2010-07-16 20:41:41 +00:00
Jordy Rose 61176897ba Pointer comparisons (and pointer-pointer subtraction). Basically filling in SimpleSValuator::EvalBinOpLL().
llvm-svn: 106992
2010-06-28 08:26:15 +00:00
Jordy Rose 895c899142 Adds analyzer support for idempotent and tautological binary operations such as "a*0" and "a+0". This is not very powerful, but does make the analyzer look a little smarter than it actually is.
llvm-svn: 106402
2010-06-20 04:56:29 +00:00