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
In r256567 I changed the nullability checker to suppress warnings about returning a null
value from a function/method with a non-null return type when the type of the returned
expression is itself nonnull. This enables the programmer to silence nullability warnings
by casting to _Nonnull:
return (SomeObject * _Nonnull)nil;
Unfortunately, under ObjC automated reference counting, Sema adds implicit casts to
_Nonnull to return expressions of nullable or unspecified types in functions with
non-null function/method return types. With r256567, these casts cause all nullability
warnings for returns of reference-counted types to be suppressed under ARC, leading to
false negatives.
This commit updates the nullability checker to look through implicit casts before
determining the type of the returned expression. It also updates the tests to turn on
ARC for the nullability_nullonly.mm testfile and adds a new testfile to test when ARC
is turned off.
rdar://problem/24200117
llvm-svn: 258061
Update NullabilityChecker so that it checks return statements in ObjC methods.
Previously it was returning early because methods do not have a function type.
Also update detection of violated parameter _Nonnull preconditions to handle
ObjC methods.
rdar://problem/24200560
llvm-svn: 257938
Provide separate visitor templates for the three hierarchies, and also
the `FullSValVisitor' class, which is a union of all three visitors.
Additionally, add a particular example visitor, `SValExplainer', in order to
test the visitor templates. This visitor is capable of explaining the SVal,
SymExpr, or MemRegion in a natural language.
Compared to the reverted r257605, this fixes the test that used to fail
on some triples, and fixes build failure under -fmodules.
Differential Revision: http://reviews.llvm.org/D15448
llvm-svn: 257893
This reverts commit r257605.
The test fails on architectures that use unsigned int as size_t.
SymbolManager.h fails with compile errors on some platforms.
llvm-svn: 257608
Provide separate visitor templates for the three hierarchies, and also
the `FullSValVisitor' class, which is a union of all three visitors.
Additionally, add a particular example visitor, `SValExplainer', in order to
test the visitor templates. This visitor is capable of explaining the SVal,
SymExpr, or MemRegion in a natural language.
Differential Revision: http://reviews.llvm.org/D15448
llvm-svn: 257605
The purpose of these changes is to simplify introduction of definition files
for the three hierarchies.
1. For every sub-class C of these classes, its kind in the relevant enumeration
is changed to "CKind" (or C##Kind in preprocessor-ish terms), eg:
MemRegionKind -> MemRegionValKind
RegionValueKind -> SymbolRegionValueKind
CastSymbolKind -> SymbolCastKind
SymIntKind -> SymIntExprKind
2. MemSpaceRegion used to be inconsistently used as both an abstract base and
a particular region. This region class is now an abstract base and no longer
occupies GenericMemSpaceRegionKind. Instead, a new class, CodeSpaceRegion,
is introduced for handling the unique use case for MemSpaceRegion as
"the generic memory space" (when it represents a memory space that holds all
executable code).
3. BEG_ prefixes in memory region kind ranges are renamed to BEGIN_ for
consisitency with symbol kind ranges.
4. FunctionTextRegion and BlockTextRegion are renamed to FunctionCodeRegion and
BlockCodeRegion, respectively. The term 'code' is less jargony than 'text' and
we already refer to BlockTextRegion as a 'code region' in BlockDataRegion.
Differential Revision: http://reviews.llvm.org/D16062
llvm-svn: 257598
Android's assert can call both the __assert and __assert2 functions under the cover, but
the NoReturnFunctionChecker does not handle the latter. This commit fixes that.
A patch by Yury Gribov!
Differential Revision: http://reviews.llvm.org/D15810
llvm-svn: 256605
Prevent the analyzer from warning when a _Nonnnull local variable is implicitly
zero-initialized because of Objective-C automated reference counting. This avoids false
positives in cases where a _Nonnull local variable cannot be initialized with an
initialization expression, such as:
NSString * _Nonnull s; // no-warning
@autoreleasepool {
s = ...;
}
The nullability checker will still warn when a _Nonnull local variable is explicitly
initialized with nil.
This suppression introduces the potential for false negatives if the local variable
is used before it is assigned a _Nonnull value. Based on a discussion with Anna Zaks,
Jordan Rose, and John McCall, I've added a FIXME to treat implicitly zero-initialized
_Nonnull locals as uninitialized in Sema's UninitializedValues analysis to avoid these
false negatives.
rdar://problem/23522311
llvm-svn: 256603
The nullability checker currently allows casts to suppress warnings when a nil
literal is passed as an argument to a parameter annotated as _Nonnull:
foo((NSString * _Nonnull)nil); // no-warning
It does so by suppressing the diagnostic when the *type* of the argument expression
is _Nonnull -- even when the symbolic value returned is known to be nil.
This commit updates the nullability checker to similarly honor such casts in the analogous
scenario when nil is returned from a function with a _Nonnull return type:
return (NSString * _Nonnull)nil; // no-warning
This commit also normalizes variable naming between the parameter and return cases and
adds several tests demonstrating the limitations of this suppression mechanism (such as
when nil is cast to _Nonnull and then stored into a local variable without a nullability
qualifier). These tests are marked with FIXMEs.
rdar://problem/23176782
llvm-svn: 256567
The intent of this checker is to generate a report for any class / structure
that could reduce its padding by reordering the fields. This results in a very
noisy checker. To reduce the noise, this checker will currently only warn when
the number of bytes over "optimal" is more than 24. This value is configurable
with -analyzer-config performance.Padding:AllowedPad=N. Small values of
AllowedPad have the potential to generate hundreds of reports, and gigabytes
of HTML reports.
The checker searches for padding violations in two main ways. First, it goes
record by record. A report is generated if the fields could be reordered in a
way that reduces the padding by more than AllowedPad bytes. Second, the
checker will generate a report if an array will cause more than AllowedPad
padding bytes to be generated.
The record checker currently skips many ABI specific cases. Classes with base
classes are skipped because base class tail padding is ABI specific. Bitfields
are just plain hard, and duplicating that code seems like a bad idea. VLAs are
both uncommon and non-trivial to fix.
The array checker isn't very thorough right now. It only checks to see if the
element type's fields could be reordered, and it doesn't recursively check to
see if any of the fields' fields could be reordered. At some point in the
future, it would be nice if "arrays" could also look at array new usages and
malloc patterns that appear to be creating arrays.
llvm-svn: 255545
SymbolReaper was destroying the symbol too early when it was referenced only
from an index SVal of a live ElementRegion.
In order to test certain aspects of this patch, extend the debug.ExprInspection
checker to allow testing SymbolReaper in a direct manner.
Differential Revision: http://reviews.llvm.org/D12726
llvm-svn: 255236
Don't warn about addresses of stack-allocated blocks escaping if the block
region was cast with CK_CopyAndAutoreleaseBlockObject. These casts, which
are introduced in the implicit conversion operator for lambda-to-block
conversions, cause the block to be copied to the heap -- so the warning is
spurious.
llvm-svn: 254639
The nullability checker was not suppressing false positives resulting from
inlined defensive checks when null was bound to a nonnull variable because it
was passing the entire bind statement rather than the value expression to
trackNullOrUndefValue().
This commit changes that checker to synactically match on the bind statement to
extract the value expression so it can be passed to trackNullOrUndefValue().
rdar://problem/23575439
llvm-svn: 254007
The analyzer currently reports dead store false positives when a local variable
is captured by reference in a C++ lambda.
For example:
int local = 0; auto lambda = [&local]() {
local++;
};
local = 7; // False Positive: Value stored to 'local' is never read
lambda();
In this case, the assignment setting `local` to 7 is not a dead store because
the called lambda will later read that assigned value.
This commit silences this source of false positives by treating locals captured
by reference in C++ lambdas as escaped, similarly to how the DeadStoresChecker
deals with locals whose address is taken.
rdar://problem/22165179
llvm-svn: 253630
This checker looks for unsafe constructs in vforked process:
function calls (excluding whitelist), memory write and returns.
This was originally motivated by a vfork-related bug in xtables package.
Patch by Yury Gribov.
Differential revision: http://reviews.llvm.org/D14014
llvm-svn: 252285
This commit creates a new 'optin' top-level checker package and moves several of
the localizability checkers into it.
This package is for checkers that are not alpha and that would normally be on by
default but where the driver does not have enough information to determine when
they are applicable. The localizability checkers fit this criterion because the
driver cannot determine whether a project is localized or not -- this is best
determined at the IDE or build-system level.
This new package is *not* intended for checkers that are too noisy to be on by
default.
The hierarchy under 'optin' mirrors that in 'alpha': checkers under 'optin'
should be organized in the hierarchy they would have had if they were truly top
level (e.g., optin.osx.cocoa.MyOptInChecker).
Differential Revision: http://reviews.llvm.org/D14303
llvm-svn: 252080
This patch should add support for almost all command-line options and
driver tinkering necessary to produce a correct "clang -cc1"
invocation for watchOS and tvOS.
llvm-svn: 251706
The analyzer assumes that system functions will not free memory or modify the
arguments in other ways, so we assume that arguments do not escape when
those are called. However, this may lead to false positive leak errors. For
example, in code like this where the pointers added to the rb_tree are freed
later on:
struct alarm_event *e = calloc(1, sizeof(*e));
<snip>
rb_tree_insert_node(&alarm_tree, e);
Add a heuristic to assume that calls to system functions taking void*
arguments allow for pointer escape.
llvm-svn: 251449
This patch adds hashes to the plist and html output to be able to identfy bugs
for suppressing false positives or diff results against a baseline. This hash
aims to be resilient for code evolution and is usable to identify bugs in two
different snapshots of the same software. One missing piece however is a
permanent unique identifier of the checker that produces the warning. Once that
issue is resolved, the hashes generated are going to change. Until that point
this feature is marked experimental, but it is suitable for early adoption.
Differential Revision: http://reviews.llvm.org/D10305
Original patch by: Bence Babati!
llvm-svn: 251011
Summary: It breaks the build for the ASTMatchers
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D13893
llvm-svn: 250827
Change the analyzer's modeling of memcpy to be more precise when copying into fixed-size
array fields. With this change, instead of invalidating the entire containing region the
analyzer now invalidates only offsets for the array itself when it can show that the
memcpy stays within the bounds of the array.
This addresses false positive memory leak warnings of the kind reported by
krzysztof in https://llvm.org/bugs/show_bug.cgi?id=22954
(This is the second attempt, now with assertion failures resolved.)
A patch by Pierre Gousseau!
Differential Revision: http://reviews.llvm.org/D12571
llvm-svn: 248516
StringRefs always point to immutable memory so the const doesn't add value
here. Also quiets clang's -Wrange-loop-analysis which warns about the implicit
copying.
llvm-svn: 248496
This patch ignores malloc-overflow bug in two cases:
Case1:
x = a/b; where n < b
malloc (x*n); Then x*n will not overflow.
Case2:
x = a; // when 'a' is a known value.
malloc (x*n);
Also replaced isa with dyn_cast.
Reject multiplication by zero cases in MallocOverflowSecurityChecker
Currently MallocOverflowSecurityChecker does not catch cases like:
malloc(n * 0 * sizeof(int));
This patch rejects such cases.
Two test cases added. malloc-overflow2.c has an example inspired from a code
in linux kernel where the current checker flags a warning while it should not.
A patch by Aditya Kumar!
Differential Revision: http://reviews.llvm.org/D9924
llvm-svn: 248446
Various improvements to the localization checker:
* Adjusted copy to be consistent with diagnostic text in other Apple
API checkers.
* Added in ~150 UIKit / AppKit methods that require localized strings in
UnlocalizedStringsChecker.
* UnlocalizedStringChecker now checks for UI methods up the class hierarchy and
UI methods that conform for a certain Objective-C protocol.
* Added in alpha version of PluralMisuseChecker and some regression tests. False
positives are still not ideal.
(This is the second attempt, with the memory issues on Linux resolved.)
A patch by Kulpreet Chilana!
Differential Revision: http://reviews.llvm.org/D12417
llvm-svn: 248432
Various improvements to the localization checker:
* Adjusted copy to be consistent with diagnostic text in other Apple
API checkers.
* Added in ~150 UIKit / AppKit methods that require localized strings in
UnlocalizedStringsChecker.
* UnlocalizedStringChecker now checks for UI methods up the class hierarchy and
UI methods that conform for a certain Objective-C protocol.
* Added in alpha version of PluralMisuseChecker and some regression tests. False
positives are still not ideal.
A patch by Kulpreet Chilana!
Differential Revision: http://reviews.llvm.org/D12417
llvm-svn: 248350
Currently realloc(ptr, 0) is treated as free() which seems to be not correct. C
standard (N1570) establishes equivalent behavior for malloc(0) and realloc(ptr,
0): "7.22.3 Memory management functions calloc, malloc, realloc: If the size of
the space requested is zero, the behavior is implementation-defined: either a
null pointer is returned, or the behavior is as if the size were some nonzero
value, except that the returned pointer shall not be used to access an object."
The patch equalizes the processing of malloc(0) and realloc(ptr,0). The patch
also enables unix.Malloc checker to detect references to zero-allocated memory
returned by realloc(ptr,0) ("Use of zero-allocated memory" warning).
A patch by Антон Ярцев!
Differential Revision: http://reviews.llvm.org/D9040
llvm-svn: 248336
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
In Objective-C, method calls with nil receivers are essentially no-ops. They
do not fault (although the returned value may be garbage depending on the
declared return type and architecture). Programmers are aware of this
behavior and will complain about a false alarm when the analyzer
diagnoses API violations for method calls when the receiver is known to
be nil.
Rather than require each individual checker to be aware of this behavior
and suppress a warning when the receiver is nil, this commit
changes ExprEngineObjC so that VisitObjCMessage skips calling checker
pre/post handlers when the receiver is definitely nil. Instead, it adds a
new event, ObjCMessageNil, that is only called in that case.
The CallAndMessageChecker explicitly cares about this case, so I've changed it
to add a callback for ObjCMessageNil and moved the logic in PreObjCMessage
that handles nil receivers to the new callback.
rdar://problem/18092611
Differential Revision: http://reviews.llvm.org/D12123
llvm-svn: 247653
This patch depends on r246688 (D12341).
The goal is to make LLVM generate different code for these functions for a target that
has cheap branches (see PR23827 for more details):
int foo();
int normal(int x, int y, int z) {
if (x != 0 && y != 0) return foo();
return 1;
}
int crazy(int x, int y) {
if (__builtin_unpredictable(x != 0 && y != 0)) return foo();
return 1;
}
Differential Revision: http://reviews.llvm.org/D12458
llvm-svn: 246699
Change the analyzer's modeling of memcpy to be more precise when copying into fixed-size
array fields. With this change, instead of invalidating the entire containing region the
analyzer now invalidates only offsets for the array itself when it can show that the
memcpy stays within the bounds of the array.
This addresses false positive memory leak warnings of the kind reported by
krzysztof in https://llvm.org/bugs/show_bug.cgi?id=22954
A patch by Pierre Gousseau!
Differential Revision: http://reviews.llvm.org/D11832
llvm-svn: 246345
Adds parsing/sema analysis/serialization/deserialization for array sections in OpenMP constructs (introduced in OpenMP 4.0).
Currently it is allowed to use array sections only in OpenMP clauses that accepts list of expressions.
Differential Revision: http://reviews.llvm.org/D10732
llvm-svn: 245937
Add checkers that detect code-level localizability issues for OS X / iOS:
- A path sensitive checker that warns about uses of non-localized
NSStrings passed to UI methods expecting localized strings.
- A syntax checker that warns against not including a comment in
NSLocalizedString macros.
A patch by Kulpreet Chilana!
(This is the second attempt with the compilation issue on Windows and
the random test failures resolved.)
llvm-svn: 245093
Make the copy/move ctors defaulted in the base class and make the
derived classes final to avoid any intermediate hierarchy slicing if
these types were further derived.
llvm-svn: 244979
(return by value is in ExprEngine::processPointerEscapedOnBind and any
other call to the scanReachableSymbols function template used there)
Protect the special members in the base class to avoid slicing, and make
derived classes final so these special members don't accidentally become
public on an intermediate base which would open up the possibility of
slicing again.
llvm-svn: 244975
After r244870 flush() will only compare two null pointers and return,
doing nothing but wasting run time. The call is not required any more
as the stream and its SmallString are always in sync.
Thanks to David Blaikie for reviewing.
llvm-svn: 244928
This reverts commit fc885033a30b6e30ccf82398ae7c30e646727b10.
Revert all localization checker commits until the proper fix is implemented.
llvm-svn: 244394
This reverts commit 57a46a75b408245cf4154a838fe13ad702065745.
Revert all localization checker commits until the proper fix is implemented.
llvm-svn: 244393
Add checkers that detect code-level localizability issues for OS X / iOS:
- A path sensitive checker that warns about uses of non-localized
NSStrings passed to UI methods expecting localized strings.
- A syntax checker that warns against not including a comment in
NSLocalizedString macros.
A patch by Kulpreet Chilana!
llvm-svn: 244389
The ObjCSuperCallChecker issues alarms for various Objective-C APIs that require
a subclass to call to its superclass's version of a method when overriding it.
So, for example, it raises an alarm when the -viewDidLoad method in a subclass
of UIViewController does not call [super viewDidLoad].
This patch fixes a false alarm where the analyzer erroneously required the
implementation of the superclass itself (e.g., UIViewController) to call
super.
rdar://problem/18416944
Differential Revision: http://reviews.llvm.org/D11842
llvm-svn: 244386
The patch is generated using this command:
$ tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
work/llvm/tools/clang
To reduce churn, not touching namespaces spanning less than 10 lines.
llvm-svn: 240270
Includes a simple static analyzer check and not much else, but we'll also
be able to take advantage of this in Swift.
This feature can be tested for using __has_feature(cf_returns_on_parameters).
This commit also contains two fixes:
- Look through non-typedef sugar when deciding whether something is a CF type.
- When (cf|ns)_returns(_not)?_retained is applied to invalid properties,
refer to "property" instead of "method" in the error message.
rdar://problem/18742441
llvm-svn: 240185
Update ObjCContainersChecker to be notified when pointers escape so it can
remove size information for escaping CFMutableArrayRefs. When such pointers
escape, un-analyzed code could mutate the array and cause the size information
to be incorrect.
rdar://problem/19406485
llvm-svn: 239709
TODO: support realloc(). Currently it is not possible due to the present realloc() handling. Currently RegionState is not being attached to realloc() in case of a zero Size argument.
llvm-svn: 234889
This is imitating a pre-r228174 state where ivars are not considered tracked by
default, but with the addition that even ivars /with/ retain count information
(e.g. "[_ivar retain]; [ivar _release];") are not being tracked as well. This is
to ensure that we don't regress on values accessed through both properties and
ivars, which is what r228174 was trying to fix.
The issue occurs in code like this:
[_contentView retain];
[_contentView removeFromSuperview];
[self addSubview:_contentView]; // invalidates 'self'
[_contentView release];
In this case, the call to -addSubview: may change the value of self->_contentView,
and so the analyzer can't be sure that we didn't leak the original _contentView.
This is a correct conservative view of the world, but not a useful one. Until we
have a heuristic that allows us to not consider this a leak, not emitting a
diagnostic is our best bet.
This commit disables all of the ivar-related retain count tests, but does not
remove them to ensure that we don't crash trying to evaluate either valid or
erroneous code. The next commit will add a new test for the example above so
that this commit (and the previous one) can be reverted wholesale when a better
solution is implemented.
Rest of rdar://problem/20335433
llvm-svn: 233592
Give up this checking in order to continue tracking that these values came from
direct ivar access, which will be important in the next commit.
Part of rdar://problem/20335433
llvm-svn: 233591
Similarly, don't assume +0 if the property's setter is manually implemented.
In both cases, if the property's ownership is explicitly written, then we /do/
assume the ivar has the same ownership.
rdar://problem/20218183
llvm-svn: 232849
Devin Coughlin