139 Commits

Author SHA1 Message Date
Balazs Benics
18f219c5ac
[analyzer][NFC] Cleanup BugType lazy-init patterns (#76655)
Cleanup most of the lazy-init `BugType` legacy.
Some will be preserved, as those are slightly more complicated to
refactor.

Notice, that the default category for `BugType` is `LogicError`. I
omitted setting this explicitly where I could.

Please, actually have a look at the diff. I did this manually, and we
rarely check the bug type descriptions and stuff in tests, so the
testing might be shallow on this one.
2024-01-01 18:53:36 +01:00
Kazu Hirata
77604d2a84 [StaticAnalyzer] Modernize ObjCNonNilReturnValueChecker (NFC) 2023-09-04 13:35:25 -07:00
Kazu Hirata
cccdf5b71d [StaticAnalyzer] Modernize ObjCLoopChecker (NFC) 2023-09-02 09:32:38 -07:00
Kazu Hirata
760e0c3537 [StaticAnalyzer] Modernize CFNumberChecker (NFC) 2023-08-20 22:08:01 -07:00
Balazs Benics
5c23e27ba1 [analyzer][NFC] Move away from using raw-for loops inside StaticAnalyzer
I'm involved with the Static Analyzer for the most part.
I think we should embrace newer language standard features and gradually
move forward.

Differential Revision: https://reviews.llvm.org/D154325
2023-07-05 08:56:13 +02:00
tripleCC
fa6b7dd520 [StaticAnalyzer] Fix false negative on NilArgChecker when creating literal object
Fix false negative on NilArgChecker when creating literal object, such
as @[nullableObject].

Patch By tripleCC!

Differential Revision: https://reviews.llvm.org/D152269
2023-06-08 16:48:24 +02:00
Piotr Fusik
898b5c9f5e [NFC] Fix "form/from" typos
Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D142007
2023-01-22 20:05:51 +01:00
Kazu Hirata
6ad0788c33 [clang] Use std::optional instead of llvm::Optional (NFC)
This patch replaces (llvm::|)Optional< with std::optional<.  I'll post
a separate patch to remove #include "llvm/ADT/Optional.h".

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-14 12:31:01 -08:00
serge-sans-paille
d9ab3e82f3
[clang] Use a StringRef instead of a raw char pointer to store builtin and call information
This avoids recomputing string length that is already known at compile time.

It has a slight impact on preprocessing / compile time, see

https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u

This a recommit of e953ae5bbc313fd0cc980ce021d487e5b5199ea4 and the subsequent fixes caa713559bd38f337d7d35de35686775e8fb5175 and 06b90e2e9c991e211fecc97948e533320a825470.

The above patchset caused some version of GCC to take eons to compile clang/lib/Basic/Targets/AArch64.cpp, as spotted in aa171833ab0017d9732e82b8682c9848ab25ff9e.
The fix is to make BuiltinInfo tables a compilation unit static variable, instead of a private static variable.

Differential Revision: https://reviews.llvm.org/D139881
2022-12-27 09:55:19 +01:00
Vitaly Buka
aa171833ab Revert "[clang] Use a StringRef instead of a raw char pointer to store builtin and call information"
Revert "Fix lldb option handling since e953ae5bbc313fd0cc980ce021d487e5b5199ea4 (part 2)"
Revert "Fix lldb option handling since e953ae5bbc313fd0cc980ce021d487e5b5199ea4"

GCC build hangs on this bot https://lab.llvm.org/buildbot/#/builders/37/builds/19104
compiling CMakeFiles/obj.clangBasic.dir/Targets/AArch64.cpp.d

The bot uses GNU 11.3.0, but I can reproduce locally with gcc (Debian 12.2.0-3) 12.2.0.

This reverts commit caa713559bd38f337d7d35de35686775e8fb5175.
This reverts commit 06b90e2e9c991e211fecc97948e533320a825470.
This reverts commit e953ae5bbc313fd0cc980ce021d487e5b5199ea4.
2022-12-25 23:12:47 -08:00
serge-sans-paille
e953ae5bbc
[clang] Use a StringRef instead of a raw char pointer to store builtin and call information
This avoids recomputing string length that is already known at compile
time.

It has a slight impact on preprocessing / compile time, see

https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u

This is a recommit of 719d98dfa841c522d8d452f0685e503538415a53 that into
account a GGC issue (probably
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92181) when dealing with
intiailizer_list and constant expressions.

Workaround this by avoiding initializer list, at the expense of a
temporary plain old array.

Differential Revision: https://reviews.llvm.org/D139881
2022-12-24 10:25:06 +01:00
serge-sans-paille
07d9ab9aa5
Revert "[clang] Use a StringRef instead of a raw char pointer to store builtin and call information"
There are still remaining issues with GCC 12, see for instance

https://lab.llvm.org/buildbot/#/builders/93/builds/12669

This reverts commit 5ce4e92264102de21760c94db9166afe8f71fcf6.
2022-12-23 13:29:21 +01:00
serge-sans-paille
5ce4e92264
[clang] Use a StringRef instead of a raw char pointer to store builtin and call information
This avoids recomputing string length that is already known at compile
time.

It has a slight impact on preprocessing / compile time, see

https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u

This is a recommit of 719d98dfa841c522d8d452f0685e503538415a53 with a
change to llvm/utils/TableGen/OptParserEmitter.cpp to cope with GCC bug
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108158

Differential Revision: https://reviews.llvm.org/D139881
2022-12-23 12:48:17 +01:00
serge-sans-paille
b7065a31b5
Revert "[clang] Use a StringRef instead of a raw char pointer to store builtin and call information"
Failing builds: https://lab.llvm.org/buildbot#builders/9/builds/19030
This is GCC specific and has been reported upstream: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108158

This reverts commit 719d98dfa841c522d8d452f0685e503538415a53.
2022-12-23 11:36:56 +01:00
serge-sans-paille
719d98dfa8
[clang] Use a StringRef instead of a raw char pointer to store builtin and call information
This avoids recomputing string length that is already known at compile
time.

It has a slight impact on preprocessing / compile time, see

https://llvm-compile-time-tracker.com/compare.php?from=3f36d2d579d8b0e8824d9dd99bfa79f456858f88&to=e49640c507ddc6615b5e503144301c8e41f8f434&stat=instructions:u

Differential Revision: https://reviews.llvm.org/D139881
2022-12-23 10:31:47 +01:00
Fangrui Song
21c4dc7997 std::optional::value => operator*/operator->
value() has undesired exception checking semantics and calls
__throw_bad_optional_access in libc++. Moreover, the API is unavailable without
_LIBCPP_NO_EXCEPTIONS on older Mach-O platforms (see
_LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS).

This fixes clang.
2022-12-17 00:42:05 +00:00
Kazu Hirata
9ddc8af97f [Checkers] Use std::optional in BasicObjCFoundationChecks.cpp (NFC)
This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-10 07:58:36 -08:00
Kazu Hirata
180600660b [StaticAnalyzer] Use std::nullopt instead of None (NFC)
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-03 11:34:24 -08:00
Kazu Hirata
cb2c8f694d [clang] Use value instead of getValue (NFC) 2022-07-13 23:39:33 -07:00
Kazu Hirata
97afce08cb [clang] Don't use Optional::hasValue (NFC)
This patch replaces Optional::hasValue with the implicit cast to bool
in conditionals only.
2022-06-25 22:26:24 -07:00
Kazu Hirata
3b7c3a654c Revert "Don't use Optional::hasValue (NFC)"
This reverts commit aa8feeefd3ac6c78ee8f67bf033976fc7d68bc6d.
2022-06-25 11:56:50 -07:00
Kazu Hirata
aa8feeefd3 Don't use Optional::hasValue (NFC) 2022-06-25 11:55:57 -07:00
Balazs Benics
96ccb690a0 [analyzer][NFC] Prefer using isa<> instead getAs<> in conditions
Depends on D125709

Reviewed By: martong

Differential Revision: https://reviews.llvm.org/D127742
2022-06-15 16:58:13 +02:00
Balazs Benics
f1b18a79b7 [analyzer][NFC] Remove dead code and modernize surroundings
Thanks @kazu for helping me clean these parts in D127799.

I'm leaving the dump methods, along with the unused visitor handlers and
the forwarding methods.

The dead parts actually helped to uncover two bugs, to which I'm going
to post separate patches.

Reviewed By: martong

Differential Revision: https://reviews.llvm.org/D127836
2022-06-15 16:50:12 +02:00
Balazs Benics
de6ba9704d [analyzer][Casting] Support isa, cast, dyn_cast of SVals
This change specializes the LLVM RTTI mechanism for SVals.
After this change, we can use the well-known `isa`, `cast`, `dyn_cast`.

Examples:

  // SVal V = ...;
  // Loc MyLoc = ...;

  bool IsInteresting = isa<loc::MemRegionVal, loc::GotoLabel>(MyLoc);
  auto MRV = cast<loc::MemRegionVal>(MyLoc);
  Optional<loc::MemRegionVal> MaybeMRV = dyn_cast<loc::MemRegionVal>(V)

The current `SVal::getAs` and `castAs` member functions are redundant at
this point, but I believe that they are still handy.

The member function version is terse and reads left-to-right, which IMO
is a great plus. However, we should probably add a variadic `isa` member
function version to have the same casting API in both cases.

Thanks for the extensive TMP help @bzcheeseman!

Reviewed By: bzcheeseman

Differential Revision: https://reviews.llvm.org/D125709
2022-06-14 13:43:04 +02:00
Balazs Benics
9ad0a90baa [analyzer][NFC] Demonstrate the use of CallDescriptionSet
Reviewed By: martong, xazax.hun

Differential Revision: https://reviews.llvm.org/D113592
2021-11-19 18:32:13 +01:00
Balazs Benics
f18da190b0 [analyzer][NFC] Switch to using CallDescription::matches() instead of isCalled()
This patch replaces each use of the previous API with the new one.
In variadic cases, it will use the ADL `matchesAny(Call, CDs...)`
variadic function.
Also simplifies some code involving such operations.

Reviewed By: martong, xazax.hun

Differential Revision: https://reviews.llvm.org/D113591
2021-11-19 18:32:13 +01:00
Balazs Benics
0b9d3a6e53 [analyzer][NFC] Separate CallDescription from CallEvent
`CallDescriptions` deserve its own translation unit.
This patch simply moves the corresponding parts.
Also includes the `CallDescription.h` where it's necessary.

Reviewed By: martong, xazax.hun, Szelethus

Differential Revision: https://reviews.llvm.org/D113587
2021-11-15 19:10:46 +01:00
Kristóf Umann
b9bca883c9 [analyzer][NFC] Don't bind values to ObjCForCollectionStmt, replace it with a GDM trait
Based on the discussion in D82598#2171312. Thanks @NoQ!

D82598 is titled "Get rid of statement liveness, because such a thing doesn't
exist", and indeed, expressions express a value, non-expression statements
don't.

if (a && get() || []{ return true; }())
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ has a value
    ~ has a value
    ~~~~~~~~~~ has a value
                  ~~~~~~~~~~~~~~~~~~~~ has a value
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ doesn't have a value

That is simple enough, so it would only make sense if we only assigned symbolic
values to expressions in the static analyzer. Yet the interface checkers can
access presents, among other strange things, the following two methods:

ProgramState::BindExpr(const Stmt *S, const LocationContext *LCtx, SVal V,
                       bool Invalidate=true)
ProgramState::getSVal(const Stmt *S, const LocationContext *LCtx)

So, what gives? Turns out, we make an exception for ReturnStmt (which we'll
leave for another time) and ObjCForCollectionStmt. For any other loops, in order
to know whether we should analyze another iteration, among other things, we
evaluate it's condition. Which is a problem for ObjCForCollectionStmt, because
it simply doesn't have one (CXXForRangeStmt has an implicit one!). In its
absence, we assigned the actual statement with a concrete 1 or 0 to indicate
whether there are any more iterations left. However, this is wildly incorrect,
its just simply not true that the for statement has a value of 1 or 0, we can't
calculate its liveness because that doesn't make any sense either, so this patch
turns it into a GDM trait.

Fixing this allows us to reinstate the assert removed in
https://reviews.llvm.org/rG032b78a0762bee129f33e4255ada6d374aa70c71.

Differential Revision: https://reviews.llvm.org/D86736
2020-09-11 15:58:48 +02:00
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
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
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
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
Artem Dergachev
5a3beea0e3 [analyzer] CFRetainReleaseChecker: Don't check C++ methods with the same name.
Don't try to understand what's going on when there's a C++ method called eg.
CFRetain().

Refactor the checker a bit, to use more modern APIs.

Differential Revision: https://reviews.llvm.org/D50866

llvm-svn: 340982
2018-08-29 22:39:20 +00:00
George Karpenkov
efef49cd2f [analyzer] [NFC] Split up RetainSummaryManager from RetainCountChecker - try #2
Turns out it can't be removed from the analyzer since it relies on CallEvent.

Moving to staticAnalyzer/core

Differential Revision: https://reviews.llvm.org/D51023

llvm-svn: 340247
2018-08-21 03:09:02 +00:00
Bruno Cardoso Lopes
bb3b7cff96 Revert "[analyzer] [NFC] Split up RetainSummaryManager from RetainCountChecker"
This reverts commit a786521fa66c72edd308baff0c08961b6d964fb1.

Bots haven't caught up yet, but broke modules build with:

../tools/clang/include/clang/StaticAnalyzer/Checkers/MPIFunctionClassifier.h:18:10:
fatal error: cyclic dependency in module 'Clang_StaticAnalyzer_Core':
Clang_StaticAnalyzer_Core -> Clang_Analysis ->
Clang_StaticAnalyzer_Checkers -> Clang_StaticAnalyzer_Core
         ^

llvm-svn: 340117
2018-08-18 03:22:11 +00:00
George Karpenkov
0ac54fad53 [analyzer] [NFC] Split up RetainSummaryManager from RetainCountChecker
ARCMigrator is using code from RetainCountChecker, which is a layering
violation (and it also does it badly, by using a different header, and
then relying on implementation being present in a header file).

This change splits up RetainSummaryManager into a separate library in
lib/Analysis, which can be used independently of a checker.

Differential Revision: https://reviews.llvm.org/D50934

llvm-svn: 340114
2018-08-18 01:45:50 +00:00
Artem Dergachev
3ccf14eb8e [analyzer] Add support for constructors of arguments.
Once CFG-side support for argument construction contexts landed in r338436,
the analyzer could make use of them to evaluate argument constructors properly.

When evaluated as calls, constructors of arguments now use the variable region
of the parameter as their target. The corresponding stack frame does not yet
exist when the parameter is constructed, and this stack frame is created
eagerly.

Construction of functions whose body is unavailable and of virtual functions
is not yet supported. Part of the reason is the analyzer doesn't consistently
use canonical declarations o identify the function in these cases, and every
re-declaration or potential override comes with its own set of parameter
declarations. Also it is less important because if the function is not
inlined, there's usually no benefit in inlining the argument constructor.

Differential Revision: https://reviews.llvm.org/D49443

llvm-svn: 339745
2018-08-15 00:33:55 +00:00
Adrian Prantl
9fc8faf9e6 Remove \brief commands from doxygen comments.
This is similar to the LLVM change https://reviews.llvm.org/D46290.

We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46320

llvm-svn: 331834
2018-05-09 01:00:01 +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
Serge Guelton
1d993270b3 Suppress all uses of LLVM_END_WITH_NULL. NFC.
Use variadic templates instead of relying on <cstdarg> + sentinel.

This enforces better type checking and makes code more readable.

Differential revision: https://reviews.llvm.org/D32550

llvm-svn: 302572
2017-05-09 19:31:30 +00:00
Anna Zaks
5b2b39065c [analyzer] Report CFNumberGetValue API misuse
This patch contains 2 improvements to the CFNumber checker:
 - Checking of CFNumberGetValue misuse.
 - Treating all CFNumber API misuse errors as non-fatal. (Previously we treated errors that could cause uninitialized memory as syncs and the truncation errors as non-fatal.)

This implements a subset of functionality from https://reviews.llvm.org/D17954.

Differential Revision: https://reviews.llvm.org/D25876

llvm-svn: 285253
2016-10-26 22:51:47 +00:00
Eugene Zelenko
0a4f3f4373 Fix some Clang-tidy readability-redundant-control-flow warnings; other minor fixes.
Differential revision: http://reviews.llvm.org/D17060

llvm-svn: 260414
2016-02-10 19:11:58 +00:00
Alexander Kornienko
9c10490efe Refactor: Simplify boolean conditional return statements in lib/StaticAnalyzer/Checkers
Summary: Use clang-tidy to simplify boolean conditional return values

Reviewers: dcoughlin, krememek

Subscribers: krememek, cfe-commits

Patch by Richard Thomson!

Differential Revision: http://reviews.llvm.org/D10021

llvm-svn: 256491
2015-12-28 13:06:58 +00:00
Anna Zaks
de14eb5b4e [static analyzer] Don't flag nil storage into NSMutableDictionary.
This is now allowed and has the behavior of removing the mapping.

llvm-svn: 252679
2015-11-11 00:49:22 +00:00
Devin Coughlin
e39bd407ba [analyzer] Add generateErrorNode() APIs to CheckerContext.
The analyzer trims unnecessary nodes from the exploded graph before reporting
path diagnostics. However, in some cases it can trim all nodes (including the
error node), leading to an assertion failure (see
https://llvm.org/bugs/show_bug.cgi?id=24184).

This commit addresses the issue by adding two new APIs to CheckerContext to
explicitly create error nodes. Unless the client provides a custom tag, these
APIs tag the node with the checker's tag -- preventing it from being trimmed.
The generateErrorNode() method creates a sink error node, while
generateNonFatalErrorNode() creates an error node for a path that should
continue being explored.

The intent is that one of these two methods should be used whenever a checker
creates an error node.

This commit updates the checkers to use these APIs. These APIs
(unlike addTransition() and generateSink()) do not take an explicit Pred node.
This is because there are not any error nodes in the checkers that were created
with an explicit different than the default (the CheckerContext's Pred node).

It also changes generateSink() to require state and pred nodes (previously
these were optional) to reduce confusion.

Additionally, there were several cases where checkers did check whether a
generated node could be null; we now explicitly check for null in these places.

This commit also includes a test case written by Ying Yi as part of
http://reviews.llvm.org/D12163 (that patch originally addressed this issue but
was reverted because it introduced false positive regressions).

Differential Revision: http://reviews.llvm.org/D12780

llvm-svn: 247859
2015-09-16 22:03:05 +00:00