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
Make sure that we do not add SymbolCast at the very boundary of
the range in which the cast would not certainly happen.
Differential Revision: http://reviews.llvm.org/D16178
llvm-svn: 258039
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
This fix a bug in RangeSet::pin causing single value ranges to be considered non conventionally ordered.
Differential Revision: http://reviews.llvm.org/D12901
llvm-svn: 257467
The current workaround for truncations not being modelled is that the evaluation of integer to integer casts are simply bypassed and so the original symbol is used as the new casted symbol (cf SimpleSValBuilder::evalCastFromNonLoc).
This lead to the issue described in PR25078, as the RangeConstraintManager associates ranges with symbols.
The new evalIntegralCast method added by this patch wont bypass the cast if it finds the range of the symbol to be greater than the maximum value of the target type.
The fix to RangeSet::pin mentioned in the initial review will be committed separately.
Differential Revision: http://reviews.llvm.org/D12901
llvm-svn: 257464
visited decls.
Due to redeclarations, the function may have different declarations used
in CallExpr and in the definition. However, we need to use a unique
declaration for both store and lookup in VisitedCallees. This patch
fixes issues with analysis in topological order. A simple test is
included.
Patch by Alex Sidorin!
Differential Revision: http://reviews.llvm.org/D15410
llvm-svn: 257318
The analyzer reports a shift by a negative value in the constructor. The bug can
be easily triggered by calling std::random_shuffle on a vector
(<rdar://problem/19658126>).
(The shift by a negative value is reported because __w0_ gets constrained to
63 by the conditions along the path:__w0_ < _WDt && __w0_ >= _WDt-1,
where _WDt is 64. In normal execution, __w0_ is not 63, it is 1 and there is
no overflow. The path is infeasible, but the analyzer does not know about that.)
llvm-svn: 256886
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
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
error: 'warning' diagnostics expected but not seen:
File clang/test/Analysis/padding_c.c Line 194 (directive at clang/test/Analysis/padding_c.c:193): Excessive padding in 'struct DefaultAttrAlign'
1 error generated.
llvm-svn: 255636
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
Add tests demonstrating that the analyzer supports generalized lambda capture. This
support falls out naturally from the work Gábor Horváth did adding C++11 lambdas to
the analyzer.
llvm-svn: 254114
This prevents spurious dead store warnings when a C++ lambda is casted to a block.
I've also added several tests documenting our still-incomplete support for lambda-to-block
casts.
rdar://problem/22236293
llvm-svn: 254107
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
When calling a ObjC method on super from inside a C++ lambda, look at the
captures to find "self". This mirrors how the analyzer handles calling super in
an ObjC block and fixes an assertion failure.
rdar://problem/23550077
llvm-svn: 253176
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
Summary:
VisitReturnStmt would create a new block with including Dtors, so the Dtors created
in VisitCompoundStmts would be in an unreachable block.
Example:
struct S {
~S();
};
void f()
{
S s;
return;
}
void g()
{
S s;
}
Before this patch, f has one additional unreachable block containing just the
destructor of S. With this patch, both f and g have the same blocks.
Reviewers: krememek
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D13973
llvm-svn: 253107
Function__builtin_signbit returns wrong value for type ppcf128 on big endian
machines. This patch fixes how value is generated in that case.
Patch by Aleksandar Beserminji.
Differential Revision: http://reviews.llvm.org/D14149
llvm-svn: 252307
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
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
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
Prevent invalidation of `this' when a method is const; fixing PR 21606.
A patch by Sean Eveson!
Differential Revision: http://reviews.llvm.org/D13099
llvm-svn: 250237
These test updates almost exclusively around the change in behavior
around enum: enums without a definition are considered incomplete except
when targeting MSVC ABIs. Since these tests are interested in the
'incomplete-enum' behavior, restrict them to %itanium_abi_triple.
llvm-svn: 249660
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
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
This fixes PR16833, in which the analyzer was using large amounts of memory
for switch statements with large case ranges.
rdar://problem/14685772
A patch by Aleksei Sidorin!
Differential Revision: http://reviews.llvm.org/D5102
llvm-svn: 248318
Summary:
`TypeTraitExpr`s are not supported by the ExprEngine today. Analyzer
creates a sink, and aborts the block. Therefore, certain bugs that
involve type traits intrinsics cannot be detected (see PR24710).
This patch creates boolean `SVal`s for `TypeTraitExpr`s, which are
evaluated by the compiler.
Test within the patch is a summary of PR24710.
Reviewers: zaks.anna, dcoughlin, krememek
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D12482
llvm-svn: 248314
Summary:
Name `Out` refers to the parameter. It is moved into the member `Out`
in ctor-init. Dereferencing null pointer will crash clang, if user
passes '-analyzer-viz-egraph-ubigraph' argument.
Reviewers: zaks.anna, krememek
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D12119
llvm-svn: 248050
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
Add an option (-analyzer-config min-blocks-for-inline-large=14) to control the function
size the inliner considers as large, in relation to "max-times-inline-large". The option
defaults to the original hard coded behaviour, which I believe should be adjustable with
the other inlining settings.
The analyzer-config test has been modified so that the analyzer will reach the
getMinBlocksForInlineLarge() method and store the result in the ConfigTable, to ensure it
is dumped by the debug checker.
A patch by Sean Eveson!
Differential Revision: http://reviews.llvm.org/D12406
llvm-svn: 247463
This is making our internal build bot fail because it results in extra warnings being
emitted past what should be sink nodes. (There is actually an example of this in the
updated malloc.c test in the reverted commit.)
I'm working on a patch to fix the original issue by adding a new checker API to explicitly
create error nodes. This API will ensure that error nodes are always tagged in order to
prevent them from being reclaimed.
This reverts commit r246188.
llvm-svn: 247103
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
The assertion is caused by reusing a “filler” ExplodedNode as an error node.
The “filler” nodes are only used for intermediate processing and are not
essential for analyzer history, so they can be reclaimed when the
ExplodedGraph is trimmed by the “collectNode” function. When a checker finds a
bug, they generate a new transition in the ExplodedGraph. The analyzer will
try to reuse the existing predecessor node. If it cannot, it creates a new
ExplodedNode, which always has a tag to uniquely identify the creation site.
The assertion is caused when the analyzer reuses a “filler” node.
In the test case, some “filler” nodes were reused and then reclaimed later
when the ExplodedGraph was trimmed. This caused an assertion because the node
was needed to generate the report. The “filler” nodes should not be reused as
error nodes. The patch adds a constraint to prevent this happening, which
solves the problem and makes the test cases pass.
Differential Revision: http://reviews.llvm.org/D11433
Patch by Ying Yi!
llvm-svn: 246188
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
This reverts commit fc885033a30b6e30ccf82398ae7c30e646727b10.
Revert all localization checker commits until the proper fix is implemented.
llvm-svn: 244394
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
BlockDecl has a poor AST representation because it doesn't carry its type
with it. Instead, the containing BlockExpr has the full type. This almost
never matters for the analyzer, but if the block decl contains static
local variables we need to synthesize a region to put them in, and this
region will necessarily not have the right type.
Even /that/ doesn't matter, unless
(1) the block calls the function or method containing the block, and
(2) the value of the block expr is used in some interesting way.
In this case, we actually end up needing the type of the block region,
and it will be set to our synthesized type. It turns out we've been doing
a terrible job faking that type -- it wasn't a block pointer type at all.
This commit fixes that to at least guarantee a block pointer type, using
the signature written by the user if there is one.
This is not really a correct answer because the block region's type will
/still/ be wrong, but further efforts to make this right in the analyzer
would probably be silly. We should just change the AST.
rdar://problem/21698099
llvm-svn: 241944
A patch by Karthik Bhat!
This patch fixes a regression introduced by r224398. Prior to r224398
we were able to analyze the following code in test-include.c and report
a null deref in this case. But post r224398 this analysis is being skipped.
E.g.
// test-include.c
#include "test-include.h"
void test(int * data) {
data = 0;
*data = 1;
}
// test-include.h
void test(int * data);
This patch uses the function body (instead of its declaration) as the location
of the function when deciding if the Decl should be analyzed with path-sensitive
analysis. (Prior to r224398, the call graph was guaranteed to have a definition
when available.)
llvm-svn: 240800
Addresses a conflict with glibc's __nonnull macro by renaming the type
nullability qualifiers as follows:
__nonnull -> _Nonnull
__nullable -> _Nullable
__null_unspecified -> _Null_unspecified
This is the major part of rdar://problem/21530726, but does not yet
provide the Darwin-specific behavior for the old names.
llvm-svn: 240596
That is,
void cf2(CFTypeRef * __nullable p CF_RETURNS_NOT_RETAINED);
is equivalent to
void cf2(CFTypeRef __nullable * __nullable p CF_RETURNS_NOT_RETAINED);
More rdar://problem/18742441
llvm-svn: 240186
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
Based on previous discussion on the mailing list, clang currently lacks support
for C99 partial re-initialization behavior:
Reference: http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-April/029188.html
Reference: http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_253.htm
This patch attempts to fix this problem.
Given the following code snippet,
struct P1 { char x[6]; };
struct LP1 { struct P1 p1; };
struct LP1 l = { .p1 = { "foo" }, .p1.x[2] = 'x' };
// this example is adapted from the example for "struct fred x[]" in DR-253;
// currently clang produces in l: { "\0\0x" },
// whereas gcc 4.8 produces { "fox" };
// with this fix, clang will also produce: { "fox" };
Differential Review: http://reviews.llvm.org/D5789
llvm-svn: 239446
Emit warning when operand to `delete` is allocated with `new[]` or
operand to `delete[]` is allocated with `new`.
rev 2 update:
`getNewExprFromInitListOrExpr` should return `dyn_cast_or_null`
instead of `dyn_cast`, since `E` might be null.
Reviewers: rtrieu, jordan_rose, rsmith
Subscribers: majnemer, cfe-commits
Differential Revision: http://reviews.llvm.org/D4661
llvm-svn: 237608
This reverts commit 742dc9b6c9686ab52860b7da39c3a126d8a97fbc.
This is generating multiple segfaults in our internal builds.
Test case coming up shortly.
llvm-svn: 237391
Emit warning when operand to `delete` is allocated with `new[]` or
operand to `delete[]` is allocated with `new`.
Reviewers: rtrieu, jordan_rose, rsmith
Subscribers: majnemer, cfe-commits
Differential Revision: http://reviews.llvm.org/D4661
llvm-svn: 237368
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
Again, this is being applied in a separate commit so that the previous commit
can be reverted while leaving the test in place.
rdar://problem/20335433
llvm-svn: 233593
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
Fixes https://llvm.org/bugs/show_bug.cgi?id=20744
struct A {
A() = default;
};
Previously the source range of the declaration of A ended at the ')'. It should
include the '= default' part as well. The same for '= delete'.
Note: this will break one of the clang-tidy fixers, which is going to be
addessed in a follow-up patch.
Differential Revision: http://reviews.llvm.org/D8465
llvm-svn: 233028
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
CloudABI also supports the arc4random() function. We can enable compiler
warnings for rand(), random() and *rand48() on this system as well.
llvm-svn: 231914
In theory we could assume a CF property is stored at +0 if there's not a custom
setter, but that's not really worth the complexity. What we do know is that a
CF property can't have ownership attributes, and so we shouldn't assume anything
about the ownership of the ivar.
rdar://problem/20076963
llvm-svn: 231553
Modules and Tooling tests in particular tend to want to change the cwd,
so we were missing test coverage in this area on Windows. It should now
be easier to write such portable tests.
llvm-svn: 231029
We expect in general that any nil value has no retain count information
associated with it; violating this results in unexpected state unification
/later/ when we decide to throw the information away. Unexpectedly caching
out can lead to an assertion failure or crash.
rdar://problem/19862648
llvm-svn: 229934
+ separate bug report for "Free alloca()" error to be able to customize checkers responsible for this error.
+ Muted "Free alloca()" error for NewDelete checker that is not responsible for c-allocated memory, turned on for unix.MismatchedDeallocator checker.
+ RefState for alloca() - to be able to detect usage of zero-allocated memory by upcoming ZeroAllocDereference checker.
+ AF_Alloca family to handle alloca() consistently - keep proper family in RefState, handle 'alloca' by getCheckIfTracked() facility, etc.
+ extra tests.
llvm-svn: 229850
PrettyStackTrace now requires the ENABLE_BACKTRACES option. We need to check for that here or these tests fail llvm-lit.
Reviewed by chandlerc
llvm-svn: 228735
to the plist output. This check_name field does not guaranteed to be the
same as the name of the checker in the future.
Reviewer: Anna Zaks
Differential Revision: http://reviews.llvm.org/D6841
llvm-svn: 228624
The analyzer thinks that ArraySubscriptExpr cannot be an r-value (ever).
However, it can be in some corner cases. Specifically, C forbids expressions
of unqualified void type from being l-values.
Note, the analyzer will keep modeling the subscript expr as an l-value. The
analyzer should be treating void* as a char array
(https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gcc/Pointer-Arith.html).
llvm-svn: 228249
Instead of handling edge cases (mostly involving blocks), where we have difficulty finding
an allocation statement, allow the allocation site to be in a parent node.
Previously we assumed that the allocation site can always be found in the same frame
as allocation, but there are scenarios in which an element is leaked in a child
frame but is allocated in the parent.
llvm-svn: 228247
A refinement of r204730, itself a refinement of r198953, to better handle
cases where an object is accessed both through a property getter and
through direct ivar access. An object accessed through a property should
always be treated as +0, i.e. not owned by the caller. However, an object
accessed through an ivar may be at +0 or at +1, depending on whether the
ivar is a strong reference. Outside of ARC, we don't always have that
information.
The previous attempt would clear out the +0 provided by a getter, but only
if that +0 hadn't already participated in other retain counting operations.
(That is, "self.foo" is okay, but "[[self.foo retain] autorelease]" is
problematic.) This turned out to not be good enough when our synthesized
getters get involved.
This commit drops the notion of "overridable" reference counting and instead
just tracks whether a value ever came from a (strong) ivar. If it has, we
allow one more release than we otherwise would. This has the added benefit
of being able to catch /some/ overreleases of instance variables, though
it's not likely to come up in practice.
We do still get some false negatives because we currently throw away
refcount state upon assigning a value into an ivar. We should probably
improve on that in the future, especially once we synthesize setters as
well as getters.
rdar://problem/18075108
llvm-svn: 228174
A patch by Daniel DeFreez!
We were previously dropping edges on re-declarations. Store the
canonical declarations in the graph to ensure that different
references to the same function end up reflected with the same call graph
node.
(Note, this might lead to performance fluctuation because call graph
is used to determine the function analysis order.)
llvm-svn: 224398
This suppresses a common false positive when analyzing libc++.
Along the way, introduce some tests to show this checker actually
works with C++ static_cast<>.
llvm-svn: 220160
The return value of mempcpy is only correct when the destination type is
one byte in size. This patch casts the argument to a char* so the
calculation is also correct for structs, ints etc.
A patch by Daniel Fahlgren!
llvm-svn: 219024
in the super class, do not issue the warning about property
in current class's protocol will not be auto synthesized.
// rdar://18179833
llvm-svn: 216769
People have been incorrectly using "-analyzer-disable-checker" to
silence analyzer warnings on a file, when analyzing a project. Add
the "-analyzer-disable-all-checks" option, which would allow the
suppression and suggest it as part of the error message for
"-analyzer-disable-checker". The idea here is to compose this with
"--analyze" so that users can selectively opt out specific files from
static analysis.
llvm-svn: 216763
Do not warn when property declared in class's protocol will be auto-synthesized
by its uper class implementation because super class has also declared this
property while this class has not. Continue to warn if current class
has declared the property also (because this declaration will not result
in a 2nd synthesis).
rdar://18152478
llvm-svn: 216753
Currently the analyzer lazily models some functions using 'BodyFarm',
which constructs a fake function implementation that the analyzer
can simulate that approximates the semantics of the function when
it is called. BodyFarm does this by constructing the AST for
such definitions on-the-fly. One strength of BodyFarm
is that all symbols and types referenced by synthesized function
bodies are contextual adapted to the containing translation unit.
The downside is that these ASTs are hardcoded in Clang's own
source code.
A more scalable model is to allow these models to be defined as source
code in separate "model" files and have the analyzer use those
definitions lazily when a function body is needed. Among other things,
it will allow more customization of the analyzer for specific APIs
and platforms.
This patch provides the initial infrastructure for this feature.
It extends BodyFarm to use an abstract API 'CodeInjector' that can be
used to synthesize function bodies. That 'CodeInjector' is
implemented using a new 'ModelInjector' in libFrontend, which lazily
parses a model file and injects the ASTs into the current translation
unit.
Models are currently found by specifying a 'model-path' as an
analyzer option; if no path is specified the CodeInjector is not
used, thus defaulting to the current behavior in the analyzer.
Models currently contain a single function definition, and can
be found by finding the file <function name>.model. This is an
initial starting point for something more rich, but it bootstraps
this feature for future evolution.
This patch was contributed by Gábor Horváth as part of his
Google Summer of Code project.
Some notes:
- This introduces the notion of a "model file" into
FrontendAction and the Preprocessor. This nomenclature
is specific to the static analyzer, but possibly could be
generalized. Essentially these are sources pulled in
exogenously from the principal translation.
Preprocessor gets a 'InitializeForModelFile' and
'FinalizeForModelFile' which could possibly be hoisted out
of Preprocessor if Preprocessor exposed a new API to
change the PragmaHandlers and some other internal pieces. This
can be revisited.
FrontendAction gets a 'isModelParsingAction()' predicate function
used to allow a new FrontendAction to recycle the Preprocessor
and ASTContext. This name could probably be made something
more general (i.e., not tied to 'model files') at the expense
of losing the intent of why it exists. This can be revisited.
- This is a moderate sized patch; it has gone through some amount of
offline code review. Most of the changes to the non-analyzer
parts are fairly small, and would make little sense without
the analyzer changes.
- Most of the analyzer changes are plumbing, with the interesting
behavior being introduced by ModelInjector.cpp and
ModelConsumer.cpp.
- The new functionality introduced by this change is off-by-default.
It requires an analyzer config option to enable.
llvm-svn: 216550
Also, make it slightly clearer what's being tested by only differentiating integer
literals based on their suffix, rather than using a very large constant.
llvm-svn: 216133
Yet more problems due to the missing CXXBindTemporaryExpr in the CFG for
default arguments.
Unfortunately we cannot just switch off inserting temporaries for the
corresponding default arguments, as that breaks existing tests
(test/SemaCXX/return-noreturn.cpp:245).
llvm-svn: 215554
In cases like:
struct C { ~C(); }
void f(C c = C());
void t() {
f();
}
We currently do not add the CXXBindTemporaryExpr for the temporary (the
code mentions that as the default parameter expressions are owned by
the declaration, we'd otherwise add the same expression multiple times),
but we add the temporary destructor pointing to the CXXBindTemporaryExpr.
We need to fix that before we can re-enable the assertion.
llvm-svn: 215357
Changes to the original patch:
- model the CFG for temporary destructors in conditional operators so that
the destructors of the true and false branch are always exclusive. This
is necessary because we must not have impossible paths for the path
based analysis to work.
- add multiple regression tests with ternary operators
Original description:
Fix modelling of non-lifetime-extended temporary destructors in the
analyzer.
Changes to the CFG:
When creating the CFG for temporary destructors, we create a structure
that mirrors the branch structure of the conditionally executed
temporary constructors in a full expression.
The branches we create use a CXXBindTemporaryExpr as terminator which
corresponds to the temporary constructor which must have been executed
to enter the destruction branch.
2. Changes to the Analyzer:
When we visit a CXXBindTemporaryExpr we mark the CXXBindTemporaryExpr as
executed in the state; when we reach a branch that contains the
corresponding CXXBindTemporaryExpr as terminator, we branch out
depending on whether the corresponding CXXBindTemporaryExpr was marked
as executed.
llvm-svn: 215096
This reverts commit r214962 because after the change the
following code doesn't compile with -Wreturn-type -Werror.
#include <cstdlib>
class NoReturn {
public:
~NoReturn() __attribute__((noreturn)) { exit(1); }
};
int check() {
true ? NoReturn() : NoReturn();
}
llvm-svn: 214998
1. Changes to the CFG:
When creating the CFG for temporary destructors, we create a structure
that mirrors the branch structure of the conditionally executed
temporary constructors in a full expression.
The branches we create use a CXXBindTemporaryExpr as terminator which
corresponds to the temporary constructor which must have been executed
to enter the destruction branch.
2. Changes to the Analyzer:
When we visit a CXXBindTemporaryExpr we mark the CXXBindTemporaryExpr as
executed in the state; when we reach a branch that contains the
corresponding CXXBindTemporaryExpr as terminator, we branch out
depending on whether the corresponding CXXBindTemporaryExpr was marked
as executed.
llvm-svn: 214962
MaterializeTemporaryExpr already contains information about the lifetime
of the temporary; if the lifetime is not the full statement, we do not
want to emit a destructor at the end of the full statement for it.
llvm-svn: 214292
This new checker, alpha.core.TestAfterDivZero, catches issues like this:
int sum = ...
int avg = sum / count; // potential division by zero...
if (count == 0) { ... } // ...caught here
Because the analyzer does not necessarily explore /all/ paths through a program,
this check is restricted to only work on zero checks that immediately follow a
division operation (/ % /= %=). This could later be expanded to handle checks
dominated by a division operation but not necessarily in the same CFG block.
Patch by Anders Rönnholm! (with very minor modifications by me)
llvm-svn: 212731
This silences false positives (leaks, use of uninitialized value) in simple
code that uses containers such as std::vector and std::list. The analyzer
cannot reason about the internal invariances of those data structures which
leads to false positives. Until we come up with a better solution to that
problem, let's just not inline the methods of the containers and allow objects
to escape whenever such methods are called.
This just extends an already existing flag "c++-container-inlining" and applies
the heuristic not only to constructors and destructors of the containers, but
to all of their methods.
We have a bunch of distinct user reports all related to this issue
(radar://16058651, radar://16580751, radar://16384286, radar://16795491
[PR19637]).
llvm-svn: 211832
When adding the implicit compound statement (required for Codegen?), the
end location was previously overridden by the start location, probably
based on the assumptions:
* The location of the compound statement should be the member's location
* The compound statement if present is the last element of a FunctionDecl
This patch changes the location of the compound statement to the
member's end location.
Code review: http://reviews.llvm.org/D4175
llvm-svn: 211344
Doing this caused us to mistakenly think we'd seen a particular state before
when we actually hadn't, which resulted in false negatives. Credit to
Rafael Auler for discovering this issue!
llvm-svn: 211209
Fixes a crash in Retain Count checker error reporting logic by handing
the allocation statement retrieval from a BlockEdge program point.
Also added a simple CFG dump routine for debugging.
llvm-svn: 210960
This applies to __attribute__((pure)) as well, but 'const' is more interesting
because many of our builtins are marked 'const'.
PR19661
llvm-svn: 208154
The assignment needs to be before the destruction of the temporary.
This patch calls out to addStmt, which invokes VisitDeclStmt, which has
all the correct logic for handling temporaries.
llvm-svn: 207985
Document and simplify ResolveCondition.
1. Introduce a temporary special case for temporary desctructors when resolving
the branch condition - in an upcoming patch, alexmc will change temporary
destructor conditions to not run through this logic, in which case we can remove
this (marked as FIXME); this currently fixes a crash.
2. Simplify ResolveCondition; while documenting the function, I noticed that it
always returns the last statement - either that statement is the condition
itself (in which case the condition was returned anyway), or the rightmost
leaf is returned; for correctness, the rightmost leaf must be evaluated anyway
(which the CFG does in the last statement), thus we can just return the last
statement in that case, too. Added an assert to verify the invariant.
llvm-svn: 207957
The constructor that comes right before a variable declaration in the CFG might
not be the initialization of that variable. Previously, we just checked that
the variable's initializer expression was different from the construction
expression, but forgot to see whether the variable had an initializer expression
at all.
Thanks for the prompting, David.
llvm-svn: 207562
While we don't model pointer-to-member operators yet (neither .* nor ->*),
CallAndMessageChecker still checks to make sure the 'this' object is not
null or undefined first. However, it also expects that the object should
always have a valid MemRegion, something that's generally important elsewhere
in the analyzer as well. Ensure this is true ahead of time, just like we do
for member access.
PR19531
llvm-svn: 207561
This also includes some infrastructure to make it easier to build multi-argument
selectors, rather than trying to use string matching on each piece. There's a bit
more setup code, but less cost at runtime.
PR18908
llvm-svn: 205827
Fixes a false positive when temporary destructors are enabled where a temporary
is destroyed after a variable is constructed but before the VarDecl itself is
processed, which occurs when the variable is in the condition of an if or while.
Patch by Alex McCarthy, with an extra test from me.
llvm-svn: 205661
For namespaces, this is consistent with mangling and GCC's debug info
behavior. For structs, GCC uses <anonymous struct> but we prefer
consistency between all anonymous entities but don't want to confuse
them with template arguments, etc, so we'll just go with parens in all
cases.
llvm-svn: 205398
If we're trying to get the zero element region of something that's not a region,
we should be returning UnknownVal, which is what ProgramState::getLValue will
do for us.
Patch by Alex McCarthy!
llvm-svn: 205327
Add M_ZERO awareness to malloc() static analysis in Clang for FreeBSD,
NetBSD, and OpenBSD in a similar fashion to O_CREAT for open(2).
These systems have a three-argument malloc() in the kernel where the
third argument contains flags; the M_ZERO flag will zero-initialize the
allocated buffer.
This should reduce the number of false positives when running static
analysis on BSD kernels.
Additionally, add kmalloc() (Linux kernel malloc()) and treat __GFP_ZERO
like M_ZERO on Linux.
Future work involves a better method of checking for named flags without
hardcoding values.
Patch by Conrad Meyer, with minor modifications by me.
llvm-svn: 204832
A refinement of r198953 to handle cases where an object is accessed both through
a property getter and through direct ivar access. An object accessed through a
property should always be treated as +0, i.e. not owned by the caller. However,
an object accessed through an ivar may be at +0 or at +1, depending on whether
the ivar is a strong reference. Outside of ARC, we don't have that information,
so we just don't track objects accessed through ivars.
With this change, accessing an ivar directly will deliberately override the +0
provided by a getter, but only if the +0 hasn't participated in other retain
counting yet. That isn't perfect, but it's already unusual for people to be
mixing property access with direct ivar access. (The primary use case for this
is in setters, init methods, and -dealloc.)
Thanks to Ted for spotting a few mistakes in private review.
<rdar://problem/16333368>
llvm-svn: 204730
Passing a pointer to an uninitialized memory buffer is normally okay,
but if the function is declared to take a pointer-to-const then it's
very unlikely it will be modifying the buffer. In this case the analyzer
should warn that there will likely be a read of uninitialized memory.
This doesn't check all elements of an array, only the first one.
It also doesn't yet check Objective-C methods, only C functions and
C++ methods.
This is controlled by a new check: alpha.core.CallAndMessageUnInitRefArg.
Patch by Per Viberg!
llvm-svn: 203822
Like the binary operator check of r201702, this actually checks the
condition of every if in a chain against every other condition, an
O(N^2) operation. In most cases N should be small enough to make this
practical, and checking all cases like this makes it much more likely
to catch a copy-paste error within the same series of branches.
Part of IdenticalExprChecker; patch by Daniel Fahlgren!
llvm-svn: 203585
null comparison when the pointer is known to be non-null.
This catches the array to pointer decay, function to pointer decay and
address of variables. This does not catch address of function since this
has been previously used to silence a warning.
Pointer to bool conversion is under -Wbool-conversion.
Pointer to null comparison is under -Wtautological-pointer-compare, a sub-group
of -Wtautological-compare.
void foo() {
int arr[5];
int x;
// warn on these conditionals
if (foo);
if (arr);
if (&x);
if (foo == null);
if (arr == null);
if (&x == null);
if (&foo); // no warning
}
llvm-svn: 202216
For now, just ignore them. Later, we could try looking through LazyCompoundVals,
but we at least shouldn't crash.
<rdar://problem/16153464>
llvm-svn: 202212
Somehow both Daniel and I missed the fact that while loops are only identical
if they have identical bodies.
Patch by Daniel Fahlgren!
llvm-svn: 201829
IdenticalExprChecker now warns if any expressions in a logical or bitwise
chain (&&, ||, &, |, or ^) are the same. Unlike the previous patch, this
actually checks all subexpressions against each other (an O(N^2) operation,
but N is likely to be small).
Patch by Daniel Fahlgren!
llvm-svn: 201702
This extends the checks for identical expressions to handle identical
statements, and compares the consequent and alternative ("then" and "else")
branches of an if-statement to see if they are identical, treating a single
statement surrounded by braces as equivalent to one without braces.
This does /not/ check subsequent branches in an if/else chain, let alone
branches that are not consecutive. This may improve in a future patch, but
it would certainly take more work.
Patch by Daniel Fahlgren!
llvm-svn: 201701
This will let us stage in the modeling of operator new. The -analyzer-config
opton 'c++-inline-allocators' is currently off by default.
Patch by Karthik Bhat!
llvm-svn: 201122
This means always walking the whole call stack for the end path node, but
we'll assume that's always fairly tractable.
<rdar://problem/15952973>
llvm-svn: 200980
redeclaration, not just when looking them up for a use -- we need the implicit
declaration to appropriately check various properties of them (notably, whether
they're deleted).
llvm-svn: 200729
Due to statement expressions supported as GCC extension, it is possible
to put 'break' or 'continue' into a loop/switch statement but outside
its body, for example:
for ( ; ({ if (first) { first = 0; continue; } 0; }); )
This code is rejected by GCC if compiled in C mode but is accepted in C++
code. GCC bug 44715 tracks this discrepancy. Clang used code generation
that differs from GCC in both modes: only statement of the third
expression of 'for' behaves as if it was inside loop body.
This change makes code generation more close to GCC, considering 'break'
or 'continue' statement in condition and increment expressions of a
loop as it was inside the loop body. It also adds error for the cases
when 'break'/'continue' appear outside loop due to this syntax. If
code generation differ from GCC, warning is issued.
Differential Revision: http://llvm-reviews.chandlerc.com/D2518
llvm-svn: 199897
If there are non-trivially-copyable types /other/ than C++ records, we
won't have a synthesized copy expression, but we can't just use a simple
load/return.
Also, add comments and shore up tests, making sure to test in both ARC
and non-ARC.
llvm-svn: 199869
Citation: C++11 [expr.shift]p1 (and the equivalent text in C11).
This fixes PR18073, but the right thing to do (as noted in the FIXME) is to
have a real checker for too-large shifts.
llvm-svn: 199405
test the CC1 layer.
This actually uncovered that the test semes to no longer be passing for
the reasons intended. =[ The name of the test would lead me to believe
that it should be testing the semantics of noreturn in the static
analyzer.... but there are in fact no -verify assertions about noreturn
that i can find. And the noreturn checker is no longer in 'alpha.core'.
It is in 'core.builtins'. The test *does* have one assertion for a null
dereference warning. This *also* isn't in 'alpha.core', but the driver
inserts a pile of other checker packages, including 'core' which has
this warning.
So I have switch the RUN line to actually do the minimal thing that this
test currently exercises, but someone who works on the static analyzer
should probably look at this and either nuke it or move it to actually
check the noreturn behavior.
llvm-svn: 199307
In preparation for making the Win32 triple imply MS ABI mode,
make all tests pass in this mode, or make them use the Itanium
mode explicitly.
Differential Revision: http://llvm-reviews.chandlerc.com/D2401
llvm-svn: 199130
In an expression like "new (a, b) Foo(x, y)", two things happen:
- Memory is allocated by calling a function named 'operator new'.
- The memory is initialized using the constructor for 'Foo'.
Currently the analyzer only models the second event, though it has special
cases for both the default and placement forms of operator new. This patch
is the first step towards properly modeling both events: it changes the CFG
so that the above expression now generates the following elements.
1. a
2. b
3. (CFGNewAllocator)
4. x
5. y
6. Foo::Foo
The analyzer currently ignores the CFGNewAllocator element, but the next
step is to treat that as a call like any other.
The CFGNewAllocator element is not added to the CFG for analysis-based
warnings, since none of them take advantage of it yet.
llvm-svn: 199123
...by synthesizing their body to be "return self->_prop;", with an extra
nudge to RetainCountChecker to still treat the value as +0 if we have no
other information.
This doesn't handle weak properties, but that's mostly correct anyway,
since they can go to nil at any time. This also doesn't apply to properties
whose implementations we can't see, since they may not be backed by an
ivar at all. And finally, this doesn't handle properties of C++ class type,
because we can't invoke the copy constructor. (Sema has actually done this
work already, but the AST it synthesizes is one the analyzer doesn't quite
handle -- it has an rvalue DeclRefExpr.)
Modeling setters is likely to be more difficult (since it requires
handling strong/copy), but not impossible.
<rdar://problem/11956898>
llvm-svn: 198953
...rather somewhere in the destructor when we try to access something and
realize the object has already been deleted. This is necessary because
the destructor is processed before the 'delete' itself.
Patch by Karthik Bhat!
llvm-svn: 198779
...even though the argument is declared "const void *", because this is
just a way to pass pointers around as objects. (Though NSData is often
a better one.)
PR18262
llvm-svn: 198710
This checker has not been updated to work with interprocedural analysis,
and actually contains both logical correctness issues but also
memory bugs. We can resuscitate it from version control once there
is focused interest in making it a real viable checker again.
llvm-svn: 198476
We have assertions for this, but a few edge cases had snuck through where
we were still unconditionally using 'int'.
<rdar://problem/15703011>
llvm-svn: 197733
Fixes <rdar://problem/15584219> and <rdar://problem/12241361>.
This change looks large, but all it does is reuse and consolidate
the delayed diagnostic logic for deprecation warnings with unavailability
warnings. By doing so, it showed various inconsistencies between the
diagnostics, which were close, but not consistent. It also revealed
some missing "note:"'s in the deprecated diagnostics that were showing
up in the unavailable diagnostics, etc.
This change also changes the wording of the core deprecation diagnostics.
Instead of saying "function has been explicitly marked deprecated"
we now saw "'X' has been been explicitly marked deprecated". It
turns out providing a bit more context is useful, and often we
got the actual term wrong or it was not very precise
(e.g., "function" instead of "destructor"). By just saying the name
of the thing that is deprecated/deleted/unavailable we define
this issue away. This diagnostic can likely be further wordsmithed
to be shorter.
llvm-svn: 197627
cstring, converted to NSString, produce the
matching AST for it. This also required some
refactoring of the previous code. // rdar://14106083
llvm-svn: 197605
This patch was submitted to the list for review and didn't receive a LGTM.
(In fact one explicit objection and one query were raised.)
This reverts commit r197295.
llvm-svn: 197299
Previously, a line like
// expected-error-re {{foo}}
treats the entirety of foo as a regex. This is inconvenient when matching type
names containing regex characters. For example, to match
"void *(class test8::A::*)(void)" inside such a regex, one would have to type
"void \*\(class test8::A::\*\)\(void\)".
This patch changes the semantics of expected-error-re to only treat the parts
of the directive wrapped in double curly braces as regexes. This avoids the
escaping problem and leads to nicer patterns for those cases; see e.g. the
change to test/Sema/format-strings-scanf.c.
(The balanced search for closing }} of a directive also makes us handle the
full directive in test\SemaCXX\constexpr-printing.cpp:41 and :53.)
Differential Revision: http://llvm-reviews.chandlerc.com/D2388
llvm-svn: 197092
Warn if both result expressions of a ternary operator (? :) are the same.
Because only one of them will be executed, this warning will fire even if
the expressions have side effects.
Patch by Anders Rönnholm and Per Viberg!
llvm-svn: 196937
This is another regression fixed by reverting r189090.
In this case, the problem is not live variables but the approach that was taken in r189090. This regression was caused by explicitly binding "true" to the condition when we take the true branch. Normally that's okay, but in this case we're planning to reuse that condition as the value of the expression.
llvm-svn: 196599
This reverts commit r189090.
The original patch introduced regressions (see the added live-variables.* tests). The patch depends on the correctness of live variable analyses, which are not computed correctly. I've opened PR18159 to track the proper resolution to this problem.
The patch was a stepping block to r189746. This is why part of the patch reverts temporary destructor tests that started crashing. The temporary destructors feature is disabled by default.
llvm-svn: 196593
New rules of invalidation/escape of the source buffer of memcpy: the source buffer contents is invalidated and escape while the source buffer region itself is neither invalidated, nor escape.
In the current modeling of memcpy the information about allocation state of regions, accessible through the source buffer, is not copied to the destination buffer and we can not track the allocation state of those regions anymore. So we invalidate/escape the source buffer indirect regions in anticipation of their being invalidated for real later. This eliminates false-positive leaks reported by the unix.Malloc and alpha.cplusplus.NewDeleteLeaks checkers for the cases like
char *f() {
void *x = malloc(47);
char *a;
memcpy(&a, &x, sizeof a);
return a;
}
llvm-svn: 194953
This is similar to r194004: because we can't reason about the data structure
invariants of std::basic_string, the analyzer decides it's possible for an
allocator to be used to deallocate the string's inline storage. Just ignore
this by walking up the stack, skipping past methods in classes with
"allocator" in the name, and seeing if we reach std::basic_string that way.
PR17866
llvm-svn: 194764
This syntactic checker looks for expressions on both sides of comparison
operators that are structurally the same. As a special case, the
floating-point idiom "x != x" for "isnan(x)" is left alone.
Currently this only checks comparison operators, but in the future we could
extend this to include logical operators or chained if-conditionals.
Checker by Per Viberg!
llvm-svn: 194236
An Objective-C for-in loop will have zero iterations if the collection is
empty. Previously, we could only detect this case if the program asked for
the collection's -count /before/ the for-in loop. Now, the analyzer
distinguishes for-in loops that had zero iterations from those with at
least one, and can use this information to constrain the result of calling
-count after the loop.
In order to make this actually useful, teach the checker that methods on
NSArray, NSDictionary, and the other immutable collection classes don't
change the count.
<rdar://problem/14992886>
llvm-svn: 194235
The path note that says "Loop body executed 0 times" has been changed to
"Loop body skipped when range is empty" for C++11 for-range loops, and to
"Loop body skipped when collection is empty" for Objective-C for-in loops.
Part of <rdar://problem/14992886>
llvm-svn: 194234
We could certainly be more precise in many of our diagnostics, but before we
were printing "Assuming x is && y", which is just ridiculous.
<rdar://problem/15167979>
llvm-svn: 193455
This ensures that variables accessible through a union are invalidated when
the union value is passed to a function. We still don't fully handle union
values, but this should at least quiet some false positives.
PR16596
llvm-svn: 193265
This patch wasn't reviewed, and isn't correctly preserving the behaviors
relied upon by QT. I don't have a direct example of fallout, but it
should go through the standard code review process. For example, it
should never have removed the QT test case that was added when fixing
those users.
llvm-svn: 193174
Due to statement expressions supported as GCC extension, it is possible
to put 'break' or 'continue' into a loop/switch statement but outside its
body, for example:
for ( ; ({ if (first) { first = 0; continue; } 0; }); )
Such usage must be diagnosed as an error, GCC rejects it. To recognize
this and similar patterns the flags BreakScope and ContinueScope are
temporarily turned off while parsing condition expression.
Differential Revision: http://llvm-reviews.chandlerc.com/D1762
llvm-svn: 193073
Since these aren't lexically in the constructor, drawing arrows would
be a horrible jump across the body of the class. We could still do
better here by skipping over unimportant initializers, but this at least
keeps everything within the body of the constructor.
<rdar://problem/14960554>
llvm-svn: 192818
This will emit a warning if a call to clang_analyzer_warnIfReached is
executed, printing REACHABLE. This is a more explicit way to declare
expected reachability than using clang_analyzer_eval or triggering
a bug (divide-by-zero or null dereference), and unlike the former will
work the same in inlined functions and top-level functions. Like the
other debug helpers, it is part of the debug.ExprInspection checker.
Patch by Jared Grubb!
llvm-svn: 191909
Also add some tests that there is actually a message and that the bug is
actually a hard error. This actually behaved correctly before, because:
- addTransition() doesn't actually add a transition if the new state is null;
it assumes you want to propagate the predecessor forward and does nothing.
- generateSink() is called in order to emit a bug report.
- If at least one new node has been generated, the predecessor node is /not/
propagated forward.
But now it's spelled out explicitly.
Found by Richard Mazorodze, who's working on a patch that may require this.
llvm-svn: 191805
...rather than trying to figure it out from the call site, and having
people complain that we guessed wrong and that a prototype-less call is
the same as a variadic call on their system. More importantly, fix a
crash when there's no decl at the call site (though we could have just
returned a default value).
<rdar://problem/15037033>
llvm-svn: 191599
Now that the CFG includes nodes for the destructors in a delete-expression,
process them in the analyzer using the same common destructor interface
currently used for local, member, and base destructors. Also, check for when
the value is known to be null, in which case no destructor is actually run.
This does not yet handle destructors for deleted /arrays/, which may need
more CFG work. It also causes a slight regression in the location of
double delete warnings; the double delete is detected at the destructor
call, which is implicit, and so is reported on the first access within the
destructor instead of at the 'delete' statement. This will be fixed soon.
Patch by Karthik Bhat!
llvm-svn: 191381
We now have symbols with floating-point type to make sure that
(double)x == (double)x comes out true, but we still can't do much with
these. For now, don't even bother trying to create a floating-point zero
value; just give up on conversion to bool.
PR14634, C++ edition.
llvm-svn: 190953
"+method_name: cannot take ownership of memory allocated by 'new'."
instead of the old
"Memory allocated by 'new' should be deallocated by 'delete', not +method_name"
llvm-svn: 190800
variable uninitialized every time we reach its (reachable) declaration, or
every time we call the surrounding function, promote the warning from
-Wmaybe-uninitialized to -Wsometimes-uninitialized.
This is still slightly weaker than desired: we should, in general, warn
if a use is uninitialized the first time it is evaluated.
llvm-svn: 190623
RegionStore tries to protect against accidentally initializing the same
region twice, but it doesn't take subregions into account very well. If
the outer region being initialized is a struct with an empty base class,
the offset of the first field in the struct will be 0. When we initialize
the base class, we may invalidate the contents of the struct by providing
a default value of Unknown (or some new symbol). We then go to initialize
the member with a zeroing constructor, only to find that the region at
that offset in the struct already has a value. The best we can do here is
to invalidate that value and continue; neither the old default value nor
the new 0 is correct for the entire struct after the member constructor call.
The correct solution for this is to track region extents in the store.
<rdar://problem/14914316>
llvm-svn: 190530
Summary:
If a noreturn destructor is executed while returning a value from a function,
the resulting CFG has had two edges to the exit block. This crashed the analyzer,
because it expects that blocks with no terminators have only one outgoing edge.
I added code to avoid creating the second edge in this case.
PS: The crashes did not manifest themselves always, as usually the
NoReturnFunctionChecker would stop program evaluation before the analyzer hit
the assertion, but in the case of lifetime extended temporaries, the checker
failed to do that (which is a separate bug in itself).
Reviewers: jordan_rose
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1513
llvm-svn: 190125
Summary:
I've had a test failure here while experimenting and I've found that it's
impossible to find what is wrong with the previous structure of the file. So I
have grouped the expected output with the function that produces it, to make
searching for discrepancies more obvious.
Reviewers: jordan_rose
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1595
llvm-svn: 190037
This paves the way for adding support for modeling the destructor of a
region before it is deleted. The statement "delete <expr>" now generates
this series of CFG elements:
1. <expr>
2. [B1.1]->~Foo() (Implicit destructor)
3. delete [B1.1]
Patch by Karthik Bhat!
llvm-svn: 189828
This is an improved version of r186498. It enables ExprEngine to reason about
temporary object destructors. However, these destructor calls are never
inlined, since this feature is still broken. Still, this is sufficient to
properly handle noreturn temporary destructors.
Now, the analyzer correctly handles expressions like "a || A()", and executes the
destructor of "A" only on the paths where "a" evaluted to false.
Temporary destructor processing is still off by default and one has to
explicitly request it by setting cfg-temporary-dtors=true.
Reviewers: jordan_rose
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1259
llvm-svn: 189746
This will never happen in the analyzed code code, but can happen for checkers
that over-eagerly dereference pointers without checking that it's safe.
UnknownVal is a harmless enough value to get back.
Fixes an issue added in r189590, caught by our internal buildbot.
llvm-svn: 189688
Summary:
Previously, Sema was reusing parts of the AST when synthesizing an assignment
operator, turning it into a AS-dag. This caused problems for the static
analyzer, which assumed an expression appears in the tree only once.
Here I make sure to always create a fresh Expr, when inserting something into
the AST, fixing PR16745 in the process.
Reviewers: doug.gregor
CC: cfe-commits, jordan_rose
Differential Revision: http://llvm-reviews.chandlerc.com/D1425
llvm-svn: 189659
Summary:
RegionStoreManager had an optimization which replaces references to empty
structs with UnknownVal. Unfortunately, this check didn't take into account
possible field members in base classes.
To address this, I changed this test to "is empty and has no base classes". I
don't consider it worth the trouble to go through base classes and check if all
of them are empty.
Reviewers: jordan_rose
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1547
llvm-svn: 189590
When casting the address of a FunctionTextRegion to bool, or when adding
constraints to such an address, use a stand-in symbol to represent the
presence or absence of the function if the function is weakly linked.
This is groundwork for possible simple availability testing checks, and
can already catch mistakes involving inverted null checks for
weakly-linked functions.
Currently, the implementation reuses the "extent" symbols, originally created
for tracking the size of a malloc region. Since FunctionTextRegions cannot
be dereferenced, the extent symbol will never be used for anything else.
Still, this probably deserves a refactoring in the future.
This patch does not attempt to support testing the presence of weak
/variables/ (global variables), which would likely require much more of
a change and a generalization of "region structure metadata", like the
current "extents", vs. "region contents metadata", like CStringChecker's
"string length".
Patch by Richard <tarka.t.otter@googlemail.com>!
llvm-svn: 189492
Summary:
-fno-exceptions does not implicitly attach a nothrow specifier to every operator
new. Even in this mode, non-nothrow new must not return a null pointer. Failure
to allocate memory can be signalled by other means, or just by killing the
program. This behaviour is consistent with the compiler - even with
-fno-exceptions, the generated code never tests for null (and would segfault if
the opeator actually happened to return null).
Reviewers: jordan_rose
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1528
llvm-svn: 189452
Summary:
Instead of digging through the ExplodedGraph, to figure out which edge brought
us here, I compute the value of conditional expression by looking at the
sub-expression values.
To do this, I needed to change the liveness algorithm a bit -- now, the full
conditional expression also depends on all atomic sub-expressions, not only the
outermost ones.
Reviewers: jordan_rose
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1340
llvm-svn: 189090
This is still an alpha checker, but we use it in certain tests to make sure
something is not being executed.
This should fix the buildbots.
llvm-svn: 188682
This keeps the analyzer from making silly assumptions, like thinking
strlen(foo)+1 could wrap around to 0. This fixes PR16558.
Patch by Karthik Bhat!
llvm-svn: 188680
This builtin does not actually evaluate its arguments for side effects,
so we shouldn't include them in the CFG. In the analyzer, rely on the
constant expression evaluator to get the proper semantics, at least for
now. (In the future, we could get ambitious and try to provide path-
sensitive size values.)
In theory, this does pose a problem for liveness analysis: a variable can
be used within the __builtin_object_size argument expression but not show
up as live. However, it is very unlikely that such a value would be used
to compute the object size and not used to access the object in some way.
<rdar://problem/14760817>
llvm-svn: 188679
This once again restores notes to following their associated warnings
in -analyzer-output=text mode. (This is still only intended for use as a
debugging aid.)
One twist is that the warning locations in "regular" analysis output modes
(plist, multi-file-plist, html, and plist-html) are reported at a different
location on the command line than in the output file, since the command
line has no path context. This commit makes -analyzer-output=text behave
like a normal output format, which means that the *command line output
will be different* in -analyzer-text mode. Again, since -analyzer-text is
a debugging aid and lo-fi stand-in for a regular output mode, this change
makes sense.
Along the way, remove a few pieces of stale code related to the path
diagnostic consumers.
llvm-svn: 188514
When a region is realloc()ed, MallocChecker records whether it was known
to be allocated or not. If it is, and the reallocation fails, the original
region has to be freed. Previously, when an allocated region escaped,
MallocChecker completely stopped tracking it, so a failed reallocation
still (correctly) wouldn't require freeing the original region. Recently,
however, MallocChecker started tracking escaped symbols, so that if it were
freed we could check that the deallocator matched the allocator. This
broke the reallocation model for whether or not a symbol was allocated.
Now, MallocChecker will actually check if a symbol is owned, and only
require freeing after a failed reallocation if it was owned before.
PR16730
llvm-svn: 188468
Various tests had sprung up over the years which had --check-prefix=ABC on the
RUN line, but "CHECK-ABC:" later on. This happened to work before, but was
strictly incorrect. FileCheck is getting stricter soon though.
Patch by Ron Ofir.
llvm-svn: 188174
Summary:
ExprEngine had code which specificaly disabled using CXXTempObjectRegions in
InitListExprs. This was a hack put in r168757 to silence a false positive.
The underlying problem seems to have been fixed in the mean time, as removing
this code doesn't seem to break anything. Therefore I propose to remove it and
solve PR16629 in the process.
Reviewers: jordan_rose
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1325
llvm-svn: 188059
We process autorelease counts when we exit functions, but if there's an
issue in a synthesized body the report will get dropped. Just skip the
processing for now and let it get handled when the caller gets around to
processing autoreleases.
(This is still suboptimal: objects autoreleased in the caller context
should never be warned about when exiting a callee context, synthesized
or not.)
Second half of <rdar://problem/14611722>
llvm-svn: 187625
Much of our diagnostic machinery is set up to assume that the report
end path location is valid. Moreover, the user may be quite confused
when something goes wrong in our BodyFarm-synthesized function bodies,
which may be simplified or modified from the real implementations.
Rather than try to make this all work somehow, just drop the report so
that we don't try to go on with an invalid source location.
Note that we still handle reports whose /paths/ go through invalid
locations, just not those that are reported in one.
We do have to be careful not to lose warnings because of this.
The impetus for this change was an autorelease being processed within
the synthesized body, and there may be other possible issues that are
worth reporting in some way. We'll take these as they come, however.
<rdar://problem/14611722>
llvm-svn: 187624
Devin Coughlin