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
Use getRedeclContext() instead of a manually-written loop and fix a comment.
A patch by Aleksei Sidorin!
Differential Revision: http://reviews.llvm.org/D15794
llvm-svn: 256524
When the analyzer evaluates a CXXConstructExpr, it looks ahead in the CFG for
the current block to detect what region the object should be constructed into.
If the constructor was directly constructed into a local variable or field
region then there is no need to explicitly bind the constructed value to
the local or field when analyzing the DeclStmt or CXXCtorInitializer that
called the constructor.
Unfortunately, there were situations in which the CXXConstructExpr was
constructed into a temporary region but when evaluating the corresponding
DeclStmt or CXXCtorInitializer the analyzer assumed the object was constructed
into the local or field. This led to spurious warnings about uninitialized
values (PR25777).
To avoid these false positives, this commit factors out the logic for
determining when a CXXConstructExpr will be directly constructed into existing
storage, adds the inverse logic to detect when the corresponding later bind can
be safely skipped, and adds assertions to make sure these two checks are in
sync.
rdar://problem/21947725
llvm-svn: 255859
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
When a C++ lambda captures a variable-length array, it creates a capture
field to store the size of the array. The initialization expression for this
capture is null, which led the analyzer to crash when initializing the field.
To avoid this, use the size expression from the VLA type to determine the
initialization value.
rdar://problem/23748072
llvm-svn: 254962
This commit prevents MemRegion::getAsOffset() from crashing when the analyzed
program casts a symbolic region of a non-record type to some derived type and
then attempts to access a field of the base type.
rdar://problem/23458069
llvm-svn: 254806
clang converts C++ lambdas to blocks with an implicit user-defined conversion
operator method on the lambda record. This method returns a block that captures a copy
of the lambda. To inline a lambda-converted block, the analyzer now calls the lambda
records's call operator method on the lambda captured by the block.
llvm-svn: 254702
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
MSVC supports 'property' attribute and allows to apply it to the declaration of an empty array in a class or structure definition.
For example:
```
__declspec(property(get=GetX, put=PutX)) int x[];
```
The above statement indicates that x[] can be used with one or more array indices. In this case, i=p->x[a][b] will be turned into i=p->GetX(a, b), and p->x[a][b] = i will be turned into p->PutX(a, b, i);
Differential Revision: http://reviews.llvm.org/D13336
llvm-svn: 254067
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
Conversions between unrelated pointer types (e.g. char * and void *) involve
bitcasts which were not properly modeled in case of static initializers. The
patch fixes this problem.
The problem was originally spotted by Artem Dergachev. Patched by Yuri Gribov!
Differential Revision: http://reviews.llvm.org/D14652
llvm-svn: 253532
Since we don't check functions in dependent contexts, we should skip blocks
in those contexts as well. This avoids an assertion failure when the
DeadStoresChecker attempts to evaluate an array subscript expression with
a dependent name type.
rdar://problem/23564220
llvm-svn: 253516
The analyzer incorrectly treats captures as references if either the original
captured variable is a reference or the variable is captured by reference.
This causes the analyzer to crash when capturing a reference type by copy
(PR24914). Fix this by refering solely to the capture field to determine when a
DeclRefExpr for a lambda capture should be treated as a reference type.
https://llvm.org/bugs/show_bug.cgi?id=24914
rdar://problem/23524412
llvm-svn: 253157
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
Update RegionStoreManager::getBinding() to return UnknownVal when trying to get
the binding for a BlockDataRegion. Previously, getBinding() would try to cast the
BlockDataRegion to a TypedValueRegion and crash. This happened when a block
was passed as a parameter to an inlined function for which
StackHintGeneratorForSymbol::getMessage() tried to generate a stack hint message.
rdar://problem/21291971
llvm-svn: 252185
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
Summary:
Dear All,
We have been looking at the following problem, where any code after the constant bound loop is not analyzed because of the limit on how many times the same block is visited, as described in bugzillas #7638 and #23438. This problem is of interest to us because we have identified significant bugs that the checkers are not locating. We have been discussing a solution involving ranges as a longer term project, but I would like to propose a patch to improve the current implementation.
Example issue:
```
for (int i = 0; i < 1000; ++i) {...something...}
int *p = 0;
*p = 0xDEADBEEF;
```
The proposal is to go through the first and last iterations of the loop. The patch creates an exploded node for the approximate last iteration of constant bound loops, before the max loop limit / block visit limit is reached. It does this by identifying the variable in the loop condition and finding the value which is “one away” from the loop being false. For example, if the condition is (x < 10), then an exploded node is created where the value of x is 9. Evaluating the loop body with x = 9 will then result in the analysis continuing after the loop, providing x is incremented.
The patch passes all the tests, with some modifications to coverage.c, in order to make the ‘function_which_gives_up’ continue to give up, since the changes allowed the analysis to progress past the loop.
This patch does introduce possible false positives, as a result of not knowing the state of variables which might be modified in the loop. I believe that, as a user, I would rather have false positives after loops than do no analysis at all. I understand this may not be the common opinion and am interested in hearing your views. There are also issues regarding break statements, which are not considered. A more advanced implementation of this approach might be able to consider other conditions in the loop, which would allow paths leading to breaks to be analyzed.
Lastly, I have performed a study on large code bases and I think there is little benefit in having “max-loop” default to 4 with the patch. For variable bound loops this tends to result in duplicated analysis after the loop, and it makes little difference to any constant bound loop which will do more than a few iterations. It might be beneficial to lower the default to 2, especially for the shallow analysis setting.
Please let me know your opinions on this approach to processing constant bound loops and the patch itself.
Regards,
Sean Eveson
SN Systems - Sony Computer Entertainment Group
Reviewers: jordan_rose, krememek, xazax.hun, zaks.anna, dcoughlin
Subscribers: krememek, xazax.hun, cfe-commits
Differential Revision: http://reviews.llvm.org/D12358
llvm-svn: 251621
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
Devin Coughlin