Commit Graph

3760 Commits

Author SHA1 Message Date
Artem Dergachev ef0aab3138 [analyzer] Add a prunable note for skipping vbase inits in subclasses.
When initialization of virtual base classes is skipped, we now tell the user
about it, because this aspect of C++ isn't very well-known.

The implementation is based on the new "note tags" feature (r358781).
In order to make use of it, allow note tags to produce prunable notes,
and move the note tag factory to CoreEngine.

Differential Revision: https://reviews.llvm.org/D61817

llvm-svn: 361682
2019-05-24 23:37:11 +00:00
Artem Dergachev 192a7474d6 [CFG] Add branch to skip vbase inits when they're handled by superclass.
This patch adds the run-time CFG branch that would skip initialization of
virtual base classes depending on whether the constructor is called from a
superclass constructor or not. Previously the Static Analyzer was already
skipping virtual base-class initializers in such constructors, but it wasn't
skipping their arguments and their potential side effects, which was causing
pr41300 (and was generally incorrect). The previous skipping behavior is
now replaced with a hard assertion that we're not even getting there due
to how our CFG works.

The new CFG element is under a CFG build option so that not to break other
consumers of the CFG by this change. Static Analyzer support for this change
is implemented.

Differential Revision: https://reviews.llvm.org/D61816

llvm-svn: 361681
2019-05-24 23:37:08 +00:00
Mandeep Singh Grang 0cdc5dddca [Analyzer] Checker for non-determinism caused by iteration of unordered container of pointers
Summary: Added a checker for non-determinism caused by iterating unordered containers like std::unordered_set containing pointer elements.

Reviewers: NoQ, george.karpenkov, whisperity, Szelethus, baloghadamsoftware

Reviewed By: Szelethus

Subscribers: mgorny, xazax.hun, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, jdoerfert, Charusso, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D59279

llvm-svn: 361664
2019-05-24 19:24:08 +00:00
Artem Dergachev 4e53032d9b [CFG] NFC: Remove implicit conversion from CFGTerminator to Stmt *.
Turn it into a variant class instead. This conversion does indeed save some code
but there's a plan to add support for more kinds of terminators that aren't
necessarily based on statements, and with those in mind it becomes more and more
confusing to have CFGTerminators implicitly convertible to a Stmt *.

Differential Revision: https://reviews.llvm.org/D61814

llvm-svn: 361586
2019-05-24 01:34:22 +00:00
Kristof Umann ac95c86511 [analyzer] List checker/plugin options in 3 categories: released, alpha, developer
Same patch as D62093, but for checker/plugin options, the only
difference being that options for alpha checkers are implicitly marked
as alpha.

Differential Revision: https://reviews.llvm.org/D62093

llvm-svn: 361566
2019-05-23 22:52:09 +00:00
Kristof Umann 7e55ed84d0 [analyzer] Hide developer-only checker/package options by default
These options are now only visible under
-analyzer-checker-option-help-developer.

Differential Revision: https://reviews.llvm.org/D61839

llvm-svn: 361561
2019-05-23 22:07:16 +00:00
Kristof Umann 5bc40d9b18 [analyzer] List checkers in 3 categories: released, alpha, developer
Previously, the only way to display the list of available checkers was
to invoke the analyzer with -analyzer-checker-help frontend flag. This
however wasn't really great from a maintainer standpoint: users came
across checkers meant strictly for development purposes that weren't to
be tinkered with, or those that were still in development. This patch
creates a clearer division in between these categories.

From now on, we'll have 3 flags to display the list checkers. These
lists are mutually exclusive and can be used in any combination (for
example to display both stable and alpha checkers).

-analyzer-checker-help: Displays the list for stable, production ready
                        checkers.

-analyzer-checker-help-alpha: Displays the list for in development
                              checkers. Enabling is discouraged
                              for non-development purposes.

-analyzer-checker-help-developer: Modeling and debug checkers. Modeling
                                  checkers shouldn't be enabled/disabled
                                  by hand, and debug checkers shouldn't
                                  be touched by users.

Differential Revision: https://reviews.llvm.org/D62093

llvm-svn: 361558
2019-05-23 21:46:51 +00:00
Kristof Umann e8df27d925 [analyzer] Add a new frontend flag to display all checker options
Add the new frontend flag -analyzer-checker-option-help to display all
checker/package options.

Differential Revision: https://reviews.llvm.org/D57858

llvm-svn: 361552
2019-05-23 20:47:28 +00:00
Adam Balogh 33160c4424 [Analyzer] Refactor begin and end symbol creation
This patch refactors begin and end symbol creation by moving symbol
conjuration into the `create...` functions. This way the functions'
responsibilities are clearer and makes possible to add more functions
handling these symbols (e.g. functions for handling the container's
size) without code multiplication.

Differential Revision: https://reviews.llvm.org/D61136

llvm-svn: 361141
2019-05-20 11:04:27 +00:00
Simon Pilgrim 3e95568dcf MIGChecker - assert we have a non-null LocationContext. NFCI.
Fixes scan-build warning.

llvm-svn: 361097
2019-05-18 11:42:19 +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 85cf76e783 [analyzer] Validate checker option names and values
Validate whether the option exists, and also whether the supplied value is of
the correct type. With this patch, invoking the analyzer should be, at least
in the frontend mode, a lot safer.

Differential Revision: https://reviews.llvm.org/D57860

llvm-svn: 361011
2019-05-17 09:51:59 +00:00
Kristof Umann 30b2307da8 [analyzer] Insert checker options into AnalyzerOption::ConfigTable
The more entries we have in AnalyzerOptions::ConfigTable, the more helpful
debug.ConfigDumper is. With this patch, I'm pretty confident that it'll now emit
the entire state of the analyzer, minus the frontend flags.

It would be nice to reserve the config table specifically to checker options
only, as storing the regular analyzer configs is kinda redundant.

Differential Revision: https://reviews.llvm.org/D57922

llvm-svn: 361006
2019-05-17 09:29:44 +00:00
Eric Fiselier 708afb56c1 Implement __builtin_LINE() et. al. to support source location capture.
Summary:
This patch implements the source location builtins `__builtin_LINE(), `__builtin_FUNCTION()`, `__builtin_FILE()` and `__builtin_COLUMN()`. These builtins are needed to implement [`std::experimental::source_location`](https://rawgit.com/cplusplus/fundamentals-ts/v2/main.html#reflection.src_loc.creation).

With the exception of `__builtin_COLUMN`, GCC also implements these builtins, and Clangs behavior is intended to match as closely as possible. 

Reviewers: rsmith, joerg, aaron.ballman, bogner, majnemer, shafik, martong

Reviewed By: rsmith

Subscribers: rnkovacs, loskutov, riccibruno, mgorny, kunitoki, alexr, majnemer, hfinkel, cfe-commits

Differential Revision: https://reviews.llvm.org/D37035

llvm-svn: 360937
2019-05-16 21:04:15 +00:00
Artem Dergachev 07c7257cdc [analyzer] RetainCount: Fix os_returns_retained_on_zero with weird return types.
The checker was crashing when it was trying to assume a structure
to be null or non-null so that to evaluate the effect of the annotation.

Differential Revision: https://reviews.llvm.org/D61958

llvm-svn: 360790
2019-05-15 18:41:32 +00:00
Artem Dergachev e41ae14581 [analyzer] MIGChecker: Fix redundant semicolon.
llvm-svn: 360739
2019-05-15 01:36:41 +00:00
Artem Dergachev 70b654fa9b [analyzer] MIGChecker: Add support for os_ref_retain().
Suppress MIG checker false positives that occur when the programmer increments
the reference count before calling a MIG destructor, and the MIG destructor
literally boils down to decrementing the reference count.

Differential Revision: https://reviews.llvm.org/D61925

llvm-svn: 360737
2019-05-15 01:19:19 +00:00
Artem Dergachev b3fc9df481 [analyzer] Fix a crash when doing RVO from within blocks.
When looking for the location context of the call site, unwrap block invocation
contexts because they are attached to the current AnalysisDeclContext
while what we need is the previous AnalysisDeclContext.

Differential Revision: https://reviews.llvm.org/D61545

llvm-svn: 360202
2019-05-07 22:33:13 +00:00
Richard Smith b9fb121a62 [c++20] Implement P1009R2: allow omitting the array bound in an array
new expression.

This was voted into C++20 as a defect report resolution, so we
retroactively apply it to all prior language modes (though it can never
actually be used before C++11 mode).

llvm-svn: 360006
2019-05-06 03:47:15 +00:00
Kristof Umann aa9d2623a0 [analyzer][UninitializedObjectChecker] PR41741: Regard all scalar types as primitive.
https://bugs.llvm.org/show_bug.cgi?id=41741

Pretty much the same as D61246 and D61106, this time for __complex__ types. Upon
further investigation, I realized that we should regard all types
Type::isScalarType returns true for as primitive, so I merged 
isMemberPointerType(), isBlockPointerType() and isAnyComplexType()` into that
instead.

I also stumbled across yet another bug,
https://bugs.llvm.org/show_bug.cgi?id=41753, but it seems to be unrelated to
this checker.

Differential Revision: https://reviews.llvm.org/D61569

llvm-svn: 359998
2019-05-05 19:42:33 +00:00
Kristof Umann 9f7fc9838a [analyzer] Don't display implementation checkers under -analyzer-checker-help, but do under the new flag -analyzer-checker-help-hidden
During my work on analyzer dependencies, I created a great amount of new
checkers that emitted no diagnostics at all, and were purely modeling some
function or another.

However, the user shouldn't really disable/enable these by hand, hence this
patch, which hides these by default. I intentionally chose not to hide alpha
checkers, because they have a scary enough name, in my opinion, to cause no
surprise when they emit false positives or cause crashes.

The patch introduces the Hidden bit into the TableGen files (you may remember
it before I removed it in D53995), and checkers that are either marked as
hidden, or are in a package that is marked hidden won't be displayed under
-analyzer-checker-help. -analyzer-checker-help-hidden, a new flag meant for
developers only, displays the full list.

Differential Revision: https://reviews.llvm.org/D60925

llvm-svn: 359720
2019-05-01 19:56:47 +00:00
Kristof Umann c21ec00d28 [analyzer][UninitializedObjectChecker] PR41611: Regard vector types as primitive
https://bugs.llvm.org/show_bug.cgi?id=41611

Similarly to D61106, the checker ran over an llvm_unreachable for vector types:

struct VectorSizeLong {
  VectorSizeLong() {}
  __attribute__((__vector_size__(16))) long x;
};

void __vector_size__LongTest() {
  VectorSizeLong v;
}
Since, according to my short research,

"The vector_size attribute is only applicable to integral and float scalars,
although arrays, pointers, and function return values are allowed in conjunction
with this construct."
[src: https://gcc.gnu.org/onlinedocs/gcc-4.6.1/gcc/Vector-Extensions.html#Vector-Extensions]

vector types are safe to regard as primitive.

Differential Revision: https://reviews.llvm.org/D61246

llvm-svn: 359539
2019-04-30 08:47:56 +00:00
Artem Dergachev ab7747b727 [analyzer] Treat functions without run-time branches as "small".
Currently we always inline functions that have no branches, i.e. have exactly
three CFG blocks: ENTRY, some code, EXIT. This makes sense because when there
are no branches, it means that there's no exponential complexity introduced
by inlining such function. Such functions also don't trigger various fundamental
problems with our inlining mechanism, such as the problem of inlined
defensive checks.

Sometimes the CFG may contain more blocks, but in practice it still has
linear structure because all directions (except, at most, one) of all branches
turned out to be unreachable. When this happens, still treat the function
as "small". This is useful, in particular, for dealing with C++17 if constexpr.

Differential Revision: https://reviews.llvm.org/D61051

llvm-svn: 359531
2019-04-30 03:01:02 +00:00
Artem Dergachev eb71c0c961 [analyzer] SmartPtrModeling: Fix a null dereference.
Don't crash when trying to model a call in which the callee is unknown
in compile time, eg. a pointer-to-member call.

Differential Revision: https://reviews.llvm.org/D61285

llvm-svn: 359530
2019-04-30 03:00:57 +00:00
Adam Balogh d538b70b44 [Analyzer] Iterator Checkers - Do an early return after handling calls
This patch is more of a fix than a real improvement: in checkPostCall()
we should return immediately after finding the right call and handling
it. This both saves unnecessary processing and double-handling calls by
mistake.

Differential Revision: https://reviews.llvm.org/D61134

llvm-svn: 359283
2019-04-26 07:30:07 +00:00
Artem Dergachev e264ac6ae1 [analyzer] RetainCount: Allow offsets in return values.
Because RetainCountChecker has custom "local" reasoning about escapes,
it has a separate facility to deal with tracked symbols at end of analysis
and check them for leaks regardless of whether they're dead or not.
This facility iterates over the list of tracked symbols and reports
them as leaks, but it needs to treat the return value specially.

Some custom allocators tend to return the value with an offset, storing
extra metadata at the beginning of the buffer. In this case the return value
would be a non-base region. In order to avoid false positives, we still need to
find the original symbol within the return value, otherwise it'll be unable
to match it to the item in the list of tracked symbols.

Differential Revision: https://reviews.llvm.org/D60991

llvm-svn: 359263
2019-04-26 02:05:15 +00:00
Artem Dergachev b591845f4b [analyzer] Fix crash when returning C++ objects from ObjC messages-to-nil.
the assertion is in fact incorrect: there is a cornercase in Objective-C++
in which a C++ object is not constructed with a constructor, but merely
zero-initialized. Namely, this happens when an Objective-C message is sent
to a nil and it is supposed to return a C++ object.

Differential Revision: https://reviews.llvm.org/D60988

llvm-svn: 359262
2019-04-26 02:05:12 +00:00
Artem Dergachev ecefce6a49 [analyzer] Add FIXMEs for alpha.unix.cstring.OutOfBounds false positives.
Caused by incorrect strlcat() modeling in r332303,
cf. https://bugs.llvm.org/show_bug.cgi?id=37687#c8

llvm-svn: 359237
2019-04-25 20:30:14 +00:00
Kristof Umann f46c58e0c6 [analyzer][UninitializedObjectChecker] PR41590: Regard _Atomic types as primitive
https://bugs.llvm.org/show_bug.cgi?id=41590

For the following code snippet, UninitializedObjectChecker crashed:

struct MyAtomicInt {
  _Atomic(int) x;
  MyAtomicInt() {}
};

void entry() {
  MyAtomicInt b;
}

The problem was that _Atomic types were not regular records, unions,
dereferencable or primitive, making the checker hit the llvm_unreachable at
lib/StaticAnalyzer/Checkers/UninitializedObject/UninitializedObjectChecker.cpp:347.
The solution is to regard these types as primitive as well. The test case shows
that with this addition, not only are we able to get rid of the crash, but we
can identify x as uninitialized.

Differential Revision: https://reviews.llvm.org/D61106

llvm-svn: 359230
2019-04-25 20:00:51 +00:00
Artem Dergachev a746f2b73c [analyzer] Fix macro names in diagnostics within bigger macros.
If macro "CHECK_X(x)" expands to something like "if (x != NULL) ...",
the "Assuming..." note no longer says "Assuming 'x' is equal to CHECK_X".

Differential Revision: https://reviews.llvm.org/D59121

llvm-svn: 359037
2019-04-23 21:30:30 +00:00
Adam Balogh d2e2e20de3 [Analyzer] Second fix for last commit for IteratorChecker
A variable was redeclared instead of assigned in an internal
block, leaving the original uninitialized. This is fixed now.

llvm-svn: 358971
2019-04-23 11:18:50 +00:00
Rafael Stahl 850361f6c1 [analyzer][CrossTU] Extend CTU to VarDecls with initializer
Summary:
The existing CTU mechanism imports `FunctionDecl`s where the definition is available in another TU. This patch extends that to VarDecls, to bind more constants.

- Add VarDecl importing functionality to CrossTranslationUnitContext
- Import Decls while traversing them in AnalysisConsumer
- Add VarDecls to CTU external mappings generator
- Name changes from "external function map" to "external definition map"

Reviewers: NoQ, dcoughlin, xazax.hun, george.karpenkov, martong

Reviewed By: xazax.hun

Subscribers: Charusso, baloghadamsoftware, mikhail.ramalho, Szelethus, donat.nagy, dkrupp, george.karpenkov, mgorny, whisperity, szepet, rnkovacs, a.sidorin, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D46421

llvm-svn: 358968
2019-04-23 11:04:41 +00:00
Adam Balogh 8f8827014d [Analyzer] Fix for previous commit
A compilation warning was in my previous commit which broke the buildbot
because it is using `-Werror` for compilation. This patch fixes this
issue.

llvm-svn: 358955
2019-04-23 07:45:10 +00:00
Adam Balogh 54976e76e6 [Analyzer] Instead of recording comparisons in interator checkers do an eager state split
Currently iterator checkers record comparison of iterator positions
and process them for keeping track the distance between them (e.g.
whether a position is the same as the end position). However this
makes some processing unnecessarily complex and it is not needed at
all: we only need to keep track between the abstract symbols stored
in these iterator positions. This patch changes this and opens the
path to comparisons to the begin() and end() symbols between the
container (e.g. size, emptiness) which are stored as symbols, not
iterator positions. The functionality of the checker is unchanged.

Differential Revision: https://reviews.llvm.org/D53701

llvm-svn: 358951
2019-04-23 07:15:55 +00:00
Artem Dergachev 727d6ca3f0 [analyzer] Unbreak body farms in presence of multiple declarations.
When growing a body on a body farm, it's essential to use the same redeclaration
of the function that's going to be used during analysis. Otherwise our
ParmVarDecls won't match the ones that are used to identify argument regions.

This boils down to trusting the reasoning in AnalysisDeclContext. We shouldn't
canonicalize the declaration before farming the body because it makes us not
obey the sophisticated decision-making process of AnalysisDeclContext.

Differential Revision: https://reviews.llvm.org/D60899

llvm-svn: 358946
2019-04-23 02:56:00 +00:00
Artem Dergachev e2a8e43160 [analyzer] PR41335: Fix crash when no-store event is in a body-farmed function.
Stuffing invalid source locations (such as those in functions produced by
body farms) into path diagnostics causes crashes.

Fix a typo in a nearby function name.

Differential Revision: https://reviews.llvm.org/D60808

llvm-svn: 358945
2019-04-23 02:50:38 +00:00
Artem Dergachev 8c6119a442 [analyzer] PR41269: Add a bit of C++ smart pointer modeling.
Implement cplusplus.SmartPtrModeling, a new checker that doesn't
emit any warnings but models methods of smart pointers more precisely.

For now the only thing it does is make `(bool) P` return false when `P`
is a freshly moved pointer. This addresses a false positive in the
use-after-move-checker.

Differential Revision: https://reviews.llvm.org/D60796

llvm-svn: 358944
2019-04-23 02:45:42 +00:00
Kristof Umann 85e0ff752c [analyzer] Move UninitializedObjectChecker out of alpha
Moved UninitializedObjectChecker from the 'alpha.cplusplus' to the
'optin.cplusplus' package.

Differential Revision: https://reviews.llvm.org/D58573

llvm-svn: 358797
2019-04-19 23:33:50 +00:00
Artem Dergachev 0a7dd5a2a4 Reapply "[analyzer] Introduce a simplified API for adding custom path notes."
This reapplies commit r357323, fixing memory leak found by LSan.

Differential Revision: https://reviews.llvm.org/D58367

llvm-svn: 358781
2019-04-19 20:23:29 +00:00
Kristof Umann b4788b26e2 [analyzer][NFC] Reimplement checker options
TL;DR:

* Add checker and package options to the TableGen files
* Added a new class called CmdLineOption, and both Package and Checker recieved
   a list<CmdLineOption> field.
* Added every existing checker and package option to Checkers.td.
* The CheckerRegistry class
  * Received some comments to most of it's inline classes
  * Received the CmdLineOption and PackageInfo inline classes, a list of
     CmdLineOption was added to CheckerInfo and PackageInfo
  * Added addCheckerOption and addPackageOption
  * Added a new field called Packages, used in addPackageOptions, filled up in
     addPackage

Detailed description:

In the last couple months, a lot of effort was put into tightening the
analyzer's command line interface. The main issue is that it's spectacularly
easy to mess up a lenghty enough invocation of the analyzer, and the user was
given no warnings or errors at all in that case.

We can divide the effort of resolving this into several chapters:

* Non-checker analyzer configurations:
    Gather every analyzer configuration into a dedicated file. Emit errors for
    non-existent configurations or incorrect values. Be able to list these
    configurations. Tighten AnalyzerOptions interface to disallow making such
    a mistake in the future.

* Fix the "Checker Naming Bug" by reimplementing checker dependencies:
    When cplusplus.InnerPointer was enabled, it implicitly registered
    unix.Malloc, which implicitly registered some sort of a modeling checker
    from the CStringChecker family. This resulted in all of these checker
    objects recieving the name "cplusplus.InnerPointer", making AnalyzerOptions
    asking for the wrong checker options from the command line:
      cplusplus.InnerPointer:Optimisic
    istead of
      unix.Malloc:Optimistic.
    This was resolved by making CheckerRegistry responsible for checker
    dependency handling, instead of checkers themselves.

* Checker options: (this patch included!)
    Same as the first item, but for checkers.

(+ minor fixes here and there, and everything else that is yet to come)

There were several issues regarding checker options, that non-checker
configurations didn't suffer from: checker plugins are loaded runtime, and they
could add new checkers and new options, meaning that unlike for non-checker
configurations, we can't collect every checker option purely by generating code.
Also, as seen from the "Checker Naming Bug" issue raised above, they are very
rarely used in practice, and all sorts of skeletons fell out of the closet while
working on this project.

They were extremely problematic for users as well, purely because of how long
they were. Consider the following monster of a checker option:

  alpha.cplusplus.UninitializedObject:CheckPointeeInitialization=false

While we were able to verify whether the checker itself (the part before the
colon) existed, any errors past that point were unreported, easily resulting
in 7+ hours of analyses going to waste.

This patch, similarly to how dependencies were reimplemented, uses TableGen to
register checker options into Checkers.td, so that Checkers.inc now contains
entries for both checker and package options. Using the preprocessor,
Checkers.inc is converted into code in CheckerRegistry, adding every builtin
(checkers and packages that have an entry in the Checkers.td file) checker and
package option to the registry. The new addPackageOption and addCheckerOption
functions expose the same functionality to statically-linked non-builtin and
plugin checkers and packages as well.

Emitting errors for incorrect user input, being able to list these options, and
some other functionalies will land in later patches.

Differential Revision: https://reviews.llvm.org/D57855

llvm-svn: 358752
2019-04-19 12:32:10 +00:00
Kristof Umann cd3f147439 [analyzer] Fix an assertion failure if plugins added dependencies
Ideally, there is no reason behind not being able to depend on checkers that
come from a different plugin (or on builtin checkers) -- however, this is only
possible if all checkers are added to the registry before resolving checker
dependencies. Since I used a binary search in my addDependency method, this also
resulted in an assertion failure (due to CheckerRegistry::Checkers not being
sorted), since the function used by plugins to register their checkers
(clang_registerCheckers) calls addDependency.

This patch resolves this issue by only noting which dependencies have to
established when addDependency is called, and resolves them at a later stage
when no more checkers are added to the registry, by which point
CheckerRegistry::Checkers is already sorted.

Differential Revision: https://reviews.llvm.org/D59461

llvm-svn: 358750
2019-04-19 11:01:35 +00:00
Fangrui Song 9206335e9d [analyzer] Fix -Wunused-local-typedef after rC358695
llvm-svn: 358729
2019-04-19 01:54:36 +00:00
Artem Dergachev 9b02a9b401 [analyzer] Make default bindings to variables actually work.
Default RegionStore bindings represent values that can be obtained by loading
from anywhere within the region, not just the specific offset within the region
that they are said to be bound to. For example, default-binding a character \0
to an int (eg., via memset()) means that the whole int is 0, not just
that its lower byte is 0.

Even though memset and bzero were modeled this way, it didn't work correctly
when applied to simple variables. Eg., in

  int x;
  memset(x, 0, sizeof(x));

we did produce a default binding, but were unable to read it later, and 'x'
was perceived as an uninitialized variable even after memset.

At the same time, if we replace 'x' with a variable of a structure or array
type, accessing fields or elements of such variable was working correctly,
which was enough for most cases. So this was only a problem for variables of
simple integer/enumeration/floating-point/pointer types.

Fix loading default bindings from RegionStore for regions of simple variables.

Add a unit test to document the API contract as well.

Differential Revision: https://reviews.llvm.org/D60742

llvm-svn: 358722
2019-04-18 23:35:56 +00:00
Kristof Umann 640f7b5875 [analyzer][NFC] Prefer binary searches in CheckerRegistry
Differential Revision: https://reviews.llvm.org/D59459

llvm-svn: 358695
2019-04-18 17:34:45 +00:00
Kristof Umann a57d4ea33f [analyzer][NFC] Clang-format CheckerRegistry
Differential Revision: https://reviews.llvm.org/D59458

llvm-svn: 358694
2019-04-18 17:32:51 +00:00
Kristof Umann b9bc7ec304 [analyzer][NFC] Use capital variable names, move methods out-of-line, rename some in CheckerRegistry
There are barely any lines I haven't changed in these files, so I think I could
might as well leave it in an LLVM coding style conforming state. I also renamed
2 functions and moved addDependency out of line to ease on followup patches.

Differential Revision: https://reviews.llvm.org/D59457

llvm-svn: 358676
2019-04-18 15:19:16 +00:00
Kristof Umann 25e592e522 [analyzer] PR41185: Fix regression where __builtin_* functions weren't recognized
For the following code snippet:

void builtin_function_call_crash_fixes(char *c) {
  __builtin_strncpy(c, "", 6);
  __builtin_memset(c, '\0', (0));
  __builtin_memcpy(c, c, 0);
}
security.insecureAPI.DeprecatedOrUnsafeBufferHandling caused a regression, as it
didn't recognize functions starting with __builtin_. Fixed exactly that.

I wanted to modify an existing test file, but the two I found didn't seem like
perfect candidates. While I was there, I prettified their RUN: lines.

Differential Revision: https://reviews.llvm.org/D59812

llvm-svn: 358609
2019-04-17 19:56:40 +00:00
Artem Dergachev 7d4694547a [analyzer] Escape pointers stored into top-level parameters with destructors.
Writing stuff into an argument variable is usually equivalent to writing stuff
to a local variable: it will have no effect outside of the function.
There's an important exception from this rule: if the argument variable has
a non-trivial destructor, the destructor would be invoked on
the parent stack frame, exposing contents of the otherwise dead
argument variable to the caller.

If such argument is the last place where a pointer is stored before the function
exits and the function is the one we've started our analysis from (i.e., we have
no caller context for it), we currently diagnose a leak. This is incorrect
because the destructor of the argument still has access to the pointer.
The destructor may deallocate the pointer or even pass it further.

Treat writes into such argument regions as "escapes" instead, suppressing
spurious memory leak reports but not messing with dead symbol removal.

Differential Revision: https://reviews.llvm.org/D60112

llvm-svn: 358321
2019-04-13 02:01:45 +00:00
Artem Dergachev 5c6fc36de8 [analyzer] NoStoreFuncVisitor: Suppress reports with no-store in system headers.
The idea behind this heuristic is that normally the visitor is there to
inform the user that a certain function may fail to initialize a certain
out-parameter. For system header functions this is usually dictated by the
contract, and it's unlikely that the header function has accidentally
forgot to put the value into the out-parameter; it's more likely
that the user has intentionally skipped the error check.

Warnings on skipped error checks are more like security warnings;
they aren't necessarily useful for all users, and they should instead
be introduced on a per-API basis.

Differential Revision: https://reviews.llvm.org/D60107

llvm-svn: 357810
2019-04-05 20:18:53 +00:00
Nico Weber 04347d848d Make SourceManager::createFileID(UnownedTag, ...) take a const llvm::MemoryBuffer*
Requires making the llvm::MemoryBuffer* stored by SourceManager const,
which in turn requires making the accessors for that return const
llvm::MemoryBuffer*s and updating all call sites.

The original motivation for this was to use it and fix the TODO in
CodeGenAction.cpp's ConvertBackendLocation() by using the UnownedTag
version of createFileID, and since llvm::SourceMgr* hands out a const
llvm::MemoryBuffer* this is required. I'm not sure if fixing the TODO
this way actually works, but this seems like a good change on its own
anyways.

No intended behavior change.

Differential Revision: https://reviews.llvm.org/D60247

llvm-svn: 357724
2019-04-04 21:06:41 +00:00