Commit Graph

63 Commits

Author SHA1 Message Date
Kirstóf Umann e4e1080a58 [analyzer][Nullability] Don't emit under the checker name NullabilityBase
Differential Revision: https://reviews.llvm.org/D78122
2020-05-19 17:04:06 +02:00
Valeriy Savchenko 09a1f09050 [analyzer] Do not report NSError null dereference for _Nonnull params.
We want to trust user type annotations and stop assuming pointers declared
as _Nonnull still can be null. This functionality is implemented as part
of NullabilityChecker as it already tracks non-null types.

Patch by Valeriy Savchenko!

Differential Revision: https://reviews.llvm.org/D77722
2020-04-20 12:33:01 +03:00
Nico Weber 7ea64ae3af [analyzer] Use IgnoreImpCasts() instead of reimplementing it.
No intended behavior change.

Differential Revision: https://reviews.llvm.org/D77022
2020-03-31 19:32:55 -04:00
Kirstóf Umann bda3dd0d98 [analyzer][NFC] Change LangOptions to CheckerManager in the shouldRegister* functions
Some checkers may not only depend on language options but also analyzer options.
To make this possible this patch changes the parameter of the shouldRegister*
function to CheckerManager to be able to query the analyzer options when
deciding whether the checker should be registered.

Differential Revision: https://reviews.llvm.org/D75271
2020-03-27 14:34:09 +01:00
Artem Dergachev 57adc37fe5 [analyzer] Nullability: Don't infer nullable when passing as nullable parameter.
You can't really infer anything from that.
2019-11-08 18:27:14 -08:00
Kristof Umann 72649423c0 [analyzer][NFC] Fix inconsistent references to checkers as "checks"
Traditionally, clang-tidy uses the term check, and the analyzer uses checker,
but in the very early years, this wasn't the case, and code originating from the
early 2010's still incorrectly refer to checkers as checks.

This patch attempts to hunt down most of these, aiming to refer to checkers as
checkers, but preserve references to callback functions (like checkPreCall) as
checks.

Differential Revision: https://reviews.llvm.org/D67140

llvm-svn: 371760
2019-09-12 19:09:24 +00:00
Artem Dergachev 6b85f8e99b [analyzer] NFC: Move getStmt() and createEndOfPath() out of PathDiagnostic.
These static functions deal with ExplodedNodes which is something we don't want
the PathDiagnostic interface to know anything about, as it's planned to be
moved out of libStaticAnalyzerCore.

Differential Revision: https://reviews.llvm.org/D67382

llvm-svn: 371659
2019-09-11 20:54:21 +00:00
Artem Dergachev 8535b8ecf2 [analyzer] NFC: Re-implement stack hints as a side map in BugReport.
That's one of the few random entities in the PathDiagnostic interface that
are specific to the Static Analyzer. By moving them out we could let
everybody use path diagnostics without linking against Static Analyzer.

Differential Revision: https://reviews.llvm.org/D67381

llvm-svn: 371658
2019-09-11 20:54:17 +00:00
Artem Dergachev 2f169e7cdd [analyzer] NFC: Introduce sub-classes for path-sensitive and basic reports.
Checkers are now required to specify whether they're creating a
path-sensitive report or a path-insensitive report by constructing an
object of the respective type.

This makes BugReporter more independent from the rest of the Static Analyzer
because all Analyzer-specific code is now in sub-classes.

Differential Revision: https://reviews.llvm.org/D66572

llvm-svn: 371450
2019-09-09 20:34:40 +00:00
Jonas Devlieghere 2b3d49b610 [Clang] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368942
2019-08-14 23:04:18 +00:00
Kristof Umann 6d716ef181 [analyzer][NFC] Refactoring BugReporter.cpp P3.: std::shared_pointer<PathDiagnosticPiece> -> PathDiagnosticPieceRef
find clang/ -type f -exec sed -i 's/std::shared_ptr<PathDiagnosticPiece>/PathDiagnosticPieceRef/g' {} \;
git diff -U3 --no-color HEAD^ | clang-format-diff-6.0 -p1 -i

Just as C++ is meant to be refactored, right?

Differential Revision: https://reviews.llvm.org/D65381

llvm-svn: 368717
2019-08-13 16:45:48 +00:00
Rui Ueyama 49a3ad21d6 Fix parameter name comments using clang-tidy. NFC.
This patch applies clang-tidy's bugprone-argument-comment tool
to LLVM, clang and lld source trees. Here is how I created this
patch:

$ git clone https://github.com/llvm/llvm-project.git
$ cd llvm-project
$ mkdir build
$ cd build
$ cmake -GNinja -DCMAKE_BUILD_TYPE=Debug \
    -DLLVM_ENABLE_PROJECTS='clang;lld;clang-tools-extra' \
    -DCMAKE_EXPORT_COMPILE_COMMANDS=On -DLLVM_ENABLE_LLD=On \
    -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ ../llvm
$ ninja
$ parallel clang-tidy -checks='-*,bugprone-argument-comment' \
    -config='{CheckOptions: [{key: StrictMode, value: 1}]}' -fix \
    ::: ../llvm/lib/**/*.{cpp,h} ../clang/lib/**/*.{cpp,h} ../lld/**/*.{cpp,h}

llvm-svn: 366177
2019-07-16 04:46:31 +00:00
Kristof Umann 83cc1b35d1 [analyzer] Remove the default value arg from getChecker*Option
Since D57922, the config table contains every checker option, and it's default
value, so having it as an argument for getChecker*Option is redundant.

By the time any of the getChecker*Option function is called, we verified the
value in CheckerRegistry (after D57860), so we can confidently assert here, as
any irregularities detected at this point must be a programmer error. However,
in compatibility mode, verification won't happen, so the default value must be
restored.

This implies something else, other than adding removing one more potential point
of failure -- debug.ConfigDumper will always contain valid values for
checker/package options!

Differential Revision: https://reviews.llvm.org/D59195

llvm-svn: 361042
2019-05-17 15:52:13 +00:00
Kristof Umann 088b1c9cdc [analyzer] Enable subcheckers to possess checker options
Under the term "subchecker", I mean checkers that do not have a checker class on
their own, like unix.MallocChecker to unix.DynamicMemoryModeling.

Since a checker object was required in order to retrieve checker options,
subcheckers couldn't possess options on their own.

This patch is also an excuse to change the argument order of getChecker*Option,
it always bothered me, now it resembles the actual command line argument
(checkername:option=value).

Differential Revision: https://reviews.llvm.org/D57579

llvm-svn: 355297
2019-03-04 00:28:16 +00:00
Fangrui Song 524b3c1810 Fix file headers. NFC
llvm-svn: 355176
2019-03-01 06:49:51 +00:00
Kristof Umann 204bf2bbb2 [analyzer] Add CheckerManager::getChecker, make sure that a registry function registers no more than 1 checker
This patch effectively fixes the almost decade old checker naming issue.
The solution is to assert when CheckerManager::getChecker is called on an
unregistered checker, and assert when CheckerManager::registerChecker is called
on a checker that is already registered.

Differential Revision: https://reviews.llvm.org/D55429

llvm-svn: 352292
2019-01-26 21:41:50 +00:00
Kristof Umann 8fd74ebfc0 [analyzer] Reimplement dependencies between checkers
Unfortunately, up until now, the fact that certain checkers depended on one
another was known, but how these actually unfolded was hidden deep within the
implementation. For example, many checkers (like RetainCount, Malloc or CString)
modelled a certain functionality, and exposed certain reportable bug types to
the user. For example, while MallocChecker models many many different types of
memory handling, the actual "unix.MallocChecker" checker the user was exposed to
was merely and option to this modeling part.

Other than this being an ugly mess, this issue made resolving the checker naming
issue almost impossible. (The checker naming issue being that if a checker
registered more than one checker within its registry function, both checker
object recieved the same name) Also, if the user explicitly disabled a checker
that was a dependency of another that _was_ explicitly enabled, it implicitly,
without "telling" the user, reenabled it.

Clearly, changing this to a well structured, declarative form, where the
handling of dependencies are done on a higher level is very much preferred.

This patch, among the detailed things later, makes checkers declare their
dependencies within the TableGen file Checkers.td, and exposes the same
functionality to plugins and statically linked non-generated checkers through
CheckerRegistry::addDependency. CheckerRegistry now resolves these dependencies,
makes sure that checkers are added to CheckerManager in the correct order,
and makes sure that if a dependency is disabled, so will be every checker that
depends on it.

In detail:

* Add a new field to the Checker class in CheckerBase.td called Dependencies,
which is a list of Checkers.
* Move unix checkers before cplusplus, as there is no forward declaration in
tblgen :/
* Add the following new checkers:
  - StackAddrEscapeBase
  - StackAddrEscapeBase
  - CStringModeling
  - DynamicMemoryModeling (base of the MallocChecker family)
  - IteratorModeling (base of the IteratorChecker family)
  - ValistBase
  - SecuritySyntaxChecker (base of bcmp, bcopy, etc...)
  - NSOrCFErrorDerefChecker (base of NSErrorChecker and  CFErrorChecker)
  - IvarInvalidationModeling (base of IvarInvalidation checker family)
  - RetainCountBase (base of RetainCount and OSObjectRetainCount)
* Clear up and registry functions in MallocChecker, happily remove old FIXMEs.
* Add a new addDependency function to CheckerRegistry.
* Neatly format RUN lines in files I looked at while debugging.

Big thanks to Artem Degrachev for all the guidance through this project!

Differential Revision: https://reviews.llvm.org/D54438

llvm-svn: 352287
2019-01-26 20:06:54 +00:00
Kristof Umann 058a7a450a [analyzer] Supply all checkers with a shouldRegister function
Introduce the boolean ento::shouldRegister##CHECKERNAME(const LangOptions &LO)
function very similarly to ento::register##CHECKERNAME. This will force every
checker to implement this function, but maybe it isn't that bad: I saw a lot of
ObjC or C++ specific checkers that should probably not register themselves based
on some LangOptions (mine too), but they do anyways.

A big benefit of this is that all registry functions now register their checker,
once it is called, registration is guaranteed.

This patch is a part of a greater effort to reinvent checker registration, more
info here: D54438#1315953

Differential Revision: https://reviews.llvm.org/D55424

llvm-svn: 352277
2019-01-26 14:23:08 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Kristof Umann 76a21502fd [analyzer][NFC] Move CheckerRegistry from the Core directory to Frontend
ClangCheckerRegistry is a very non-obvious, poorly documented, weird concept.
It derives from CheckerRegistry, and is placed in lib/StaticAnalyzer/Frontend,
whereas it's base is located in lib/StaticAnalyzer/Core. It was, from what I can
imagine, used to circumvent the problem that the registry functions of the
checkers are located in the clangStaticAnalyzerCheckers library, but that
library depends on clangStaticAnalyzerCore. However, clangStaticAnalyzerFrontend
depends on both of those libraries.

One can make the observation however, that CheckerRegistry has no place in Core,
it isn't used there at all! The only place where it is used is Frontend, which
is where it ultimately belongs.

This move implies that since
include/clang/StaticAnalyzer/Checkers/ClangCheckers.h only contained a single function:

class CheckerRegistry;

void registerBuiltinCheckers(CheckerRegistry &registry);

it had to re purposed, as CheckerRegistry is no longer available to
clangStaticAnalyzerCheckers. It was renamed to BuiltinCheckerRegistration.h,
which actually describes it a lot better -- it does not contain the registration
functions for checkers, but only those generated by the tblgen files.

Differential Revision: https://reviews.llvm.org/D54436

llvm-svn: 349275
2018-12-15 16:23:51 +00:00
Raphael Isemann b23ccecbb0 Misc typos fixes in ./lib folder
Summary: Found via `codespell -q 3 -I ../clang-whitelist.txt -L uint,importd,crasher,gonna,cant,ue,ons,orign,ned`

Reviewers: teemperor

Reviewed By: teemperor

Subscribers: teemperor, jholewinski, jvesely, nhaehnle, whisperity, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D55475

llvm-svn: 348755
2018-12-10 12:37:46 +00:00
Artem Dergachev cf439eda2d Re-apply r347954 "[analyzer] Nullability: Don't detect post factum violation..."
Buildbot failures were caused by an unrelated UB that was introduced in r347943
and fixed in r347970.

Also the revision was incorrectly specified as r344580 during revert.

Differential Revision: https://reviews.llvm.org/D54017

llvm-svn: 348188
2018-12-03 21:04:30 +00:00
Artem Dergachev c076907384 Revert r344580 "[analyzer] Nullability: Don't detect post factum violation..."
Fails under ASan!

llvm-svn: 347956
2018-11-30 04:26:17 +00:00
Artem Dergachev 34d3576736 [analyzer] Nullability: Don't detect post factum violation on concrete values.
The checker suppresses warnings on paths on which a nonnull value is assumed
to be nullable. This probably deserves a warning, but it's a separate story.

Now, because dead symbol collection fires in pretty random moments,
there sometimes was a situation when dead symbol collection fired after
computing a parameter but before actually evaluating call enter into the
function, which triggered the suppression when the argument was null
in the first place earlier than the obvious warning for null-to-nonnull
was emitted, causing false negatives.

Only trigger the suppression for symbols, not for concrete values.

It is impossible to constrain a concrete value post-factum because
it is impossible to constrain a concrete value at all.

This covers all the necessary cases because by the time we reach the call,
symbolic values should be either not constrained to null, or already collapsed
into concrete null values. Which in turn happens because they are passed through
the Store, and the respective collapse is implemented as part of getSVal(),
which is also weird.

Differential Revision: https://reviews.llvm.org/D54017

llvm-svn: 347954
2018-11-30 03:39:58 +00:00
Artem Dergachev bbc6d68297 [analyzer] Fix the "Zombie Symbols" bug.
It's an old bug that consists in stale references to symbols remaining in the
GDM if they disappear from other program state sections as a result of any
operation that isn't the actual dead symbol collection. The most common example
here is:

   FILE *fp = fopen("myfile.txt", "w");
   fp = 0; // leak of file descriptor

In this example the leak were not detected previously because the symbol
disappears from the public part of the program state due to evaluating
the assignment. For that reason the checker never receives a notification
that the symbol is dead, and never reports a leak.

This patch not only causes leak false negatives, but also a number of other
problems, including false positives on some checkers.

What's worse, even though the program state contains a finite number of symbols,
the set of symbols that dies is potentially infinite. This means that is
impossible to compute the set of all dead symbols to pass off to the checkers
for cleaning up their part of the GDM.

No longer compute the dead set at all. Disallow iterating over dead symbols.
Disallow querying if any symbols are dead. Remove the API for marking symbols
as dead, as it is no longer necessary. Update checkers accordingly.

Differential Revision: https://reviews.llvm.org/D18860

llvm-svn: 347953
2018-11-30 03:27:50 +00:00
Kristof Umann 0a1f91c80c [analyzer] Restrict AnalyzerOptions' interface so that non-checker objects have to be registered
One of the reasons why AnalyzerOptions is so chaotic is that options can be
retrieved from the command line whenever and wherever. This allowed for some
options to be forgotten for a looooooong time. Have you ever heard of
"region-store-small-struct-limit"? In order to prevent this in the future, I'm
proposing to restrict AnalyzerOptions' interface so that only checker options
can be retrieved without special getters. I would like to make every option be
accessible only through a getter, but checkers from plugins are a thing, so I'll
have to figure something out for that.

This also forces developers who'd like to add a new option to register it
properly in the .def file.

This is done by

* making the third checker pointer parameter non-optional, and checked by an
  assert to be non-null.
* I added new, but private non-checkers option initializers, meant only for
  internal use,
* Renamed these methods accordingly (mind the consistent name for once with
  getBooleanOption!):
  - getOptionAsString -> getCheckerStringOption,
  - getOptionAsInteger -> getCheckerIntegerOption
* The 3 functions meant for initializing data members (with the not very
  descriptive getBooleanOption, getOptionAsString and getOptionAsUInt names)
  were renamed to be overloads of the getAndInitOption function name.
* All options were in some way retrieved via getCheckerOption. I removed it, and
  moved the logic to getStringOption and getCheckerStringOption. This did cause
  some code duplication, but that's the only way I could do it, now that checker
  and non-checker options are separated. Note that the non-checker version
  inserts the new option to the ConfigTable with the default value, but the
  checker version only attempts to find already existing entries. This is how
  it always worked, but this is clunky and I might end reworking that too, so we
  can eventually get a ConfigTable that contains the entire configuration of the
  analyzer.

Differential Revision: https://reviews.llvm.org/D53483

llvm-svn: 346113
2018-11-05 03:50:37 +00:00
George Karpenkov b2cf0063d0 [analyzer] Rename trackNullOrUndefValue to trackExpressionValue
trackNullOrUndefValue is a long and confusing name,
and it does not actually reflect what the function is doing.
Give a function a new name, with a relatively clear semantics.

Also remove some dead code.

Differential Revision: https://reviews.llvm.org/D52758

llvm-svn: 345064
2018-10-23 18:24:53 +00:00
George Karpenkov c82d457db5 [analyzer] [NFC] Remove unused parameters, as found by -Wunused-parameter
Differential Revision: https://reviews.llvm.org/D52640

llvm-svn: 343353
2018-09-28 18:49:41 +00:00
Stephen Kelly f2ceec4811 Port getLocStart -> getBeginLoc
Reviewers: teemperor!

Subscribers: jholewinski, whisperity, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D50350

llvm-svn: 339385
2018-08-09 21:08:08 +00:00
George Karpenkov 70ec1dd14d [analyzer] Do not run visitors until the fixpoint, run only once.
In the current implementation, we run visitors until the fixed point is
reached.
That is, if a visitor adds another visitor, the currently processed path
is destroyed, all diagnostics is discarded, and it is regenerated again,
until it's no longer modified.
This pattern has a few negative implications:

 - This loop does not even guarantee to terminate.
   E.g. just imagine two visitors bouncing a diagnostics around.
 - Performance-wise, e.g. for sqlite3 all visitors are being re-run at
   least 10 times for some bugs.
   We have already seen a few reports where it leads to timeouts.
 - If we want to add more computationally intense visitors, this will
   become worse.
 - From architectural standpoint, the current layout requires copying
   visitors, which is conceptually wrong, and can be annoying (e.g. no
   unique_ptr on visitors allowed).

The proposed change is a much simpler architecture: the outer loop
processes nodes upwards, and whenever the visitor is added it only
processes current nodes and above, thus guaranteeing termination.

Differential Revision: https://reviews.llvm.org/D47856

llvm-svn: 335666
2018-06-26 21:12:08 +00:00
Alexander Kornienko 2a8c18d991 Fix typos in clang
Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:

  archtype
  cas
  classs
  checkk
  compres
  definit
  frome
  iff
  inteval
  ith
  lod
  methode
  nd
  optin
  ot
  pres
  statics
  te
  thru

Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)

Differential revision: https://reviews.llvm.org/D44188

llvm-svn: 329399
2018-04-06 15:14:32 +00:00
George Karpenkov 2301c5ab4d [analyzer] Trust _Nonnull annotations for system framework
Changes the analyzer to believe that methods annotated with _Nonnull
from system frameworks indeed return non null objects.
Local methods with such annotation are still distrusted.
rdar://24291919

Differential Revision: https://reviews.llvm.org/D44341

llvm-svn: 328282
2018-03-23 00:16:03 +00:00
George Karpenkov d703ec94a9 [analyzer] introduce getSVal(Stmt *) helper on ExplodedNode, make sure the helper is used consistently
In most cases using
`N->getState()->getSVal(E, N->getLocationContext())`
is ugly, verbose, and also opens up more surface area for bugs if an
inconsistent location context is used.

This patch introduces a helper on an exploded node, and ensures
consistent usage of either `ExplodedNode::getSVal` or
`CheckContext::getSVal` across the codebase.
As a result, a large number of redundant lines is removed.

Differential Revision: https://reviews.llvm.org/D42155

llvm-svn: 322753
2018-01-17 20:27:29 +00:00
Artem Dergachev fbe891ee05 [analyzer] Nullability: fix notes around synthesized ObjC property accessors.
Nullable-to-nonnull checks used to crash when the custom bug visitor was trying
to add its notes to autosynthesized accessors of Objective-C properties.

Now we avoid this, mostly automatically outside of checker control, by
moving the diagnostic to the parent stack frame where the accessor has been
called.

Differential revision: https://reviews.llvm.org/D32437

llvm-svn: 304710
2017-06-05 12:40:03 +00:00
Artem Dergachev b6a513d1b2 [analyzer] Fix memory error bug category capitalization.
It was written as "Memory Error" in most places and as "Memory error" in a few
other places, however it is the latter that is more consistent with
other categories (such as "Logic error").

rdar://problem/31718115

Differential Revision: https://reviews.llvm.org/D32702

llvm-svn: 302016
2017-05-03 11:47:13 +00:00
Simon Pilgrim 2c51880a82 Spelling mistakes in comments. NFCI. (PR27635)
llvm-svn: 299083
2017-03-30 14:13:19 +00:00
David Blaikie 0a0c275ffd Migrate PathDiagnosticPiece to std::shared_ptr
Simplifies and makes explicit the memory ownership model rather than
implicitly passing/acquiring ownership.

llvm-svn: 291143
2017-01-05 17:26:53 +00:00
Anna Zaks 6d4e76b988 [analyzer] Refine the diagnostics in the nullability checker to differentiate between nil and null
This is a big deal for ObjC, where nullability annotations are extensively
used. I've also changed "Null" -> "null" and removed "is" as this is the
pattern that Sema is using.

Differential Revision: https://reviews.llvm.org/D27600

llvm-svn: 289885
2016-12-15 22:55:15 +00:00
Devin Coughlin c894ac8163 [analyzer] Fix typo in nullability checker diagnostic
'infered' --> 'inferred'

llvm-svn: 288922
2016-12-07 17:36:27 +00:00
Devin Coughlin e4224cc9f7 [analyzer] Fix crash in NullabilityChecker calling block with too few arguments
Fix a crash when checking parameter nullability on a block invocation
with fewer arguments than the block declaration requires.

rdar://problem/29237566

llvm-svn: 286901
2016-11-14 22:46:02 +00:00
Gabor Horvath 6ee4f905dc [analyzer] Small cleanups when checkers retrieving statements from exploded
nodes.

Differential Revision: https://reviews.llvm.org/D23550

llvm-svn: 279037
2016-08-18 07:54:50 +00:00
Devin Coughlin 4ac12425ba [analyzer] Nullability: Suppress diagnostic on bind with cast.
Update the nullability checker to allow an explicit cast to nonnull to
suppress a warning on an assignment of nil to a nonnull:

id _Nonnull x = (id _Nonnull)nil; // no-warning

This suppression as already possible for diagnostics on returns and
function/method arguments.

rdar://problem/25381178

llvm-svn: 266219
2016-04-13 17:59:24 +00:00
Devin Coughlin b2d2a018d6 [analyzer] Nullability: Treat nil _Nonnull ivar as invariant violation.
Treat a _Nonnull ivar that is nil as an invariant violation in a similar
fashion to how a nil _Nonnull parameter is treated as a precondition violation.

This avoids warning on defensive returns of nil on defensive internal
checks, such as the following common idiom:

@class InternalImplementation
@interface PublicClass {
  InternalImplementation * _Nonnull _internal;
}
-(id _Nonnull)foo;
@end

@implementation PublicClass
-(id _Nonnull)foo {
  if (!_internal)
    return nil; // no-warning

  return [_internal foo];
}
@end

rdar://problem/24485171

llvm-svn: 266157
2016-04-13 00:41:54 +00:00
Devin Coughlin 49bd58f1eb [analyzer] Nullability: Suppress return diagnostics in inlined functions.
The nullability checker can sometimes miss detecting nullability precondition
violations in inlined functions because the binding for the parameter
that violated the precondition becomes dead before the return:

int * _Nonnull callee(int * _Nonnull p2) {
  if (!p2)
    // p2 becomes dead here, so binding removed.
    return 0; // warning here because value stored in p2 is symbolic.
  else
   return p2;
}

int *caller(int * _Nonnull p1) {
  return callee(p1);
}

The fix, which is quite blunt, is to not warn about null returns in inlined
methods/functions. This won’t lose much coverage for ObjC because the analyzer
always analyzes each ObjC method at the top level in addition to inlined. It
*will* lose coverage for C — but there aren’t that many codebases with C
nullability annotations.

rdar://problem/25615050

llvm-svn: 266109
2016-04-12 19:29:52 +00:00
Devin Coughlin 77942db0b8 [analyzer] Nullability: Don't warn along paths where null returned from non-null.
Change the nullability checker to not warn along paths where null is returned from
a method with a non-null return type, even when the diagnostic for this return
has been suppressed. This prevents warning from methods with non-null return types
that inline methods that themselves return nil but that suppressed the diagnostic.

Also change the PreconditionViolated state component to be called "InvariantViolated"
because it is set when a post-condition is violated, as well.

rdar://problem/25393539

llvm-svn: 264647
2016-03-28 20:30:25 +00:00
Devin Coughlin a1d9d75a88 [analyzer] Nullability: add option to not report on calls to system headers.
Add an -analyzer-config 'nullability:NoDiagnoseCallsToSystemHeaders' option to
the nullability checker. When enabled, this option causes the analyzer to not
report about passing null/nullable values to functions and methods declared
in system headers.

This option is motivated by the observation that large projects may have many
nullability warnings. These projects may find warnings about nullability
annotations that they have explicitly added themselves higher priority to fix
than warnings on calls to system libraries.

llvm-svn: 262763
2016-03-05 01:32:43 +00:00
Anna Zaks ad9e7ea6d7 [analyzer] Improve Nullability checker diagnostics
- Include the position of the argument on which the nullability is violated
- Differentiate between a 'method' and a 'function' in the message wording
- Test for the error message text in the tests
- Fix a bug with setting 'IsDirectDereference' which resulted in regular dereferences assumed to have call context.

llvm-svn: 259221
2016-01-29 18:43:15 +00:00
Devin Coughlin 134de6ffd8 [analyzer] NullabilityChecker: Remove unused isReturnSelf() function.
Remove the now-unused isReturnSelf() function so we don't get a compiler
warning. Apologies for not doing this in r259099.

llvm-svn: 259118
2016-01-28 23:34:13 +00:00
Devin Coughlin de21767a4d [analyzer] Suppress nullability warnings in copy, mutableCopy, and init families.
There are multiple, common idioms of defensive nil-checks in copy,
mutableCopy, and init methods in ObjC. The analyzer doesn't currently have the
capability to distinguish these idioms from true positives, so suppress all
warnings about returns in those families. This is a pretty blunt suppression
that we should improve later.

rdar://problem/24395811

llvm-svn: 259099
2016-01-28 22:23:34 +00:00
Devin Coughlin 4a330201ff [analyzer] Suppress nullability warning for defensive super initializer idiom.
A common idiom in Objective-C initializers is for a defensive nil-check on the
result of a call to a super initializer:
  if (self = [super init]) {
     ...
  }
  return self;

To avoid warning on this idiom, the nullability checker now suppress diagnostics
for returns of nil on syntactic 'return self' even in initializers with non-null
return types.

llvm-svn: 258461
2016-01-22 01:01:11 +00:00