This is faster for the analyzer to process than inlining the constructor
and performing a member-wise copy, and it also solves the problem of
warning when a partially-initialized POD struct is copied.
Before:
CGPoint p;
p.x = 0;
CGPoint p2 = p; <-- assigned value is garbage or undefined
After:
CGPoint p;
p.x = 0;
CGPoint p2 = p; // no-warning
This matches our behavior in C, where we don't see a field-by-field copy.
<rdar://problem/12305288>
llvm-svn: 173951
When the analyzer sees an initializer, it checks if the initializer
contains a CXXConstructExpr. If so, it trusts that the CXXConstructExpr
does the necessary work to initialize the object, and performs no further
initialization.
This patch looks through any implicit wrapping expressions like
ExprWithCleanups to find the CXXConstructExpr inside.
Fixes PR15070.
llvm-svn: 173557
The idea is to introduce a higher level "user mode" option for
different use scenarios. For example, if one wants to run the analyzer
for a small project each time the code is built, they would use
the "shallow" mode.
The user mode option will influence the default settings for the
lower-level analyzer options. For now, this just influences the ipa
modes, but we plan to find more optimal settings for them.
llvm-svn: 173386
The idea is to eventually place all analyzer options under
"analyzer-config". In addition, this lays the ground for introduction of
a high-level analyzer mode option, which will influence the
default setting for IPAMode.
llvm-svn: 173385
Before:
Calling implicit default constructor for 'Foo' (where Foo is constructed)
Entered call from 'test' (at "=default" or 'Foo' declaration)
Calling default constructor for 'Bar' (at "=default" or 'Foo' declaration)
After:
Calling implicit default constructor for 'Foo' (where Foo is constructed)
Calling default constructor for 'Bar' (at "=default" or 'Foo' declaration)
This only affects the plist diagnostics; this note is never shown in the
other diagnostics.
llvm-svn: 172915
Suppress the warning by just not emitting the report. The sink node
would get generated, which is fine since we did reach a bad state.
Motivation
Due to the way code is structured in some of these macros, we do not
reason correctly about it and report false positives. Specifically, the
following loop reports a use-after-free. Because of the way the code is
structured inside of the macro, the analyzer assumes that the list can
have cycles, so you end up with use-after-free in the loop, that is
safely deleting elements of the list. (The user does not have a way to
teach the analyzer about shape of data structures.)
SLIST_FOREACH_SAFE(item, &ctx->example_list, example_le, tmpitem) {
if (item->index == 3) { // if you remove each time, no complaints
assert((&ctx->example_list)->slh_first == item);
SLIST_REMOVE(&ctx->example_list, item, example_s, example_le);
free(item);
}
}
llvm-svn: 172883
The issue here is that if we have 2 leaks reported at the same line for
which we cannot print the corresponding region info, they will get
treated as the same by issue_hash+description. We need to AUGMENT the
issue_hash with the allocation info to differentiate the two issues.
Add the "hash" (offset from the beginning of a function) representing
allocation site to solve the issue.
We might want to generalize solution in the future when we decide to
track more than just the 2 locations from the diagnostics.
llvm-svn: 171825
Instead of using several callbacks to identify the pointer escape event,
checkers now can register for the checkPointerEscape.
Converted the Malloc checker to use the new callback.
SimpleStreamChecker will be converted next.
llvm-svn: 170625
performance heuristic
After inlining a function with more than 13 basic blocks 32 times, we
are not going to inline it anymore. The idea is that inlining large
functions leads to drastic performance implications. Since the function
has already been inlined, we know that we've analyzed it in many
contexts.
The following metrics are used:
- Large function is a function with more than 13 basic blocks (we
should switch to another metric, like cyclomatic complexity)
- We consider that we've inlined a function many times if it's been
inlined 32 times. This number is configurable with -analyzer-config
max-times-inline-large=xx
This heuristic addresses a performance regression introduced with
inlining on one benchmark. The analyzer on this benchmark became 60
times slower with inlining turned on. The heuristic allows us to analyze
it in 24% of the time. The performance improvements on the other
benchmarks I've tested with are much lower - under 10%, which is
expected.
llvm-svn: 170361
We don't handle array destructors correctly yet, but we now apply the same
hack (explicitly destroy the first element, implicitly invalidate the rest)
for multidimensional arrays that we already use for linear arrays.
<rdar://problem/12858542>
llvm-svn: 170000
top level.
This heuristic is already turned on for non-ObjC methods
(inlining-mode=noredundancy). If a method has been previously analyzed,
while being inlined inside of another method, do not reanalyze it as top
level.
This commit applies it to ObjCMethods as well. The main caveat here is
that to catch the retain release errors, we are still going to reanalyze
all the ObjC methods but without inlining turned on.
Gives 21% performance increase on one heavy ObjC benchmark, which
suffered large performance regressions due to ObjC inlining.
llvm-svn: 169639
This is the case where the analyzer tries to print out source locations
for code within a synthesized function body, which of course does not have
a valid source location. The previous fix attempted to do this during
diagnostic path pruning, but some diagnostics have pruning disabled, and
so any diagnostic with a path that goes through a synthesized body will
either hit an assertion or emit invalid output.
<rdar://problem/12657843> (again)
llvm-svn: 169631
This reduces analysis time by 1.2% on one test case (Objective-C), but
also cleans up some of the code conceptually as well. We can possible
just make RegionBindingsRef -> RegionBindings, but I wanted to stage
things.
After this, we should revisit Jordan's optimization of not canonicalizing
the immutable AVL trees for the cluster bindings as well.
llvm-svn: 169571
Previously we would search for the last statement, then back up to the
entrance of the block that contained that statement. Now, while we're
scanning for the statement, we just keep track of which blocks are being
exited (in reverse order).
llvm-svn: 169526
This doesn't seem to make much of a difference in practice, but it does
have the potential to avoid a trip through the constraint manager.
llvm-svn: 169524
Whenever we touch a single bindings cluster multiple times, we can delay
canonicalizing it until the final access. This has some interesting
implications, in particular that we shouldn't remove an /empty/ cluster
from the top-level map until canonicalization.
This is good for a 2% speedup or so on the test case in
<rdar://problem/12810842>
llvm-svn: 169523
This feature was probably intended to improve diagnostics, but was currently
only used when dumping the Environment. It shows what location a given value
was loaded from, e.g. when evaluating an LValueToRValue cast.
llvm-svn: 169522
uncovered.
This required manually correcting all of the incorrect main-module
headers I could find, and running the new llvm/utils/sort_includes.py
script over the files.
I also manually added quite a few missing headers that were uncovered by
shuffling the order or moving headers up to be main-module-headers.
llvm-svn: 169237
The stop-gap here is to just drop such objects when processing the InitListExpr.
We still need a better solution.
Fixes <rdar://problem/12755044>.
llvm-svn: 168757
This was also covered by <rdar://problem/12753384>. The static analyzer
evaluates a CXXConstructExpr within an initializer expression and
RegionStore doesn't know how to handle the resulting CXXTempObjectRegion
that gets created. We need a better solution than just dropping the
value, but we need to better understand how to implement the right
semantics here.
Thanks to Jordan for his help diagnosing the behavior here.
llvm-svn: 168741
The AllocaRegion did not have the superRegion (based on LocationContext)
as part of it's hash. As a consequence, the AllocaRegions from
different frames were uniqued to be the same region.
llvm-svn: 168599
In code like this:
void foo() {
bar();
baz();
}
...the location for the call to 'bar()' was being used as a backup location
for the call to 'baz()'. This is fine unless the call to 'bar()' is deemed
uninteresting and that part of the path deleted.
(This looks like a logic error as well, but in practice the only way 'baz()'
could have an invalid location is if the entire body of 'foo()' is
synthesized, meaning the call to 'bar()' will be using the location of the
call to 'foo()' anyway. Nevertheless, the new version better matches the
intent of the code.)
Found by Matt Beaumont-Gay using ASan. Thanks, Matt!
llvm-svn: 168080
This fixes a few cases where we'd emit path notes like this:
+---+
1| v
p = malloc(len);
^ |2
+---+
In general this should make path notes more consistent and more correct,
especially in cases where the leak happens on the false branch of an if
that jumps directly to the end of the function. There are a couple places
where the leak is reported farther away from the cause; these are usually
cases where there are several levels of nested braces before the end of
the function. This still matches our current behavior for when there /is/
a statement after all the braces, though.
llvm-svn: 168070
This allows us to properly remove dead bindings at the end of the top-level
stack frame, using the ReturnStmt, if there is one, to keep the return value
live. This in turn removes the need for a check::EndPath callback in leak
checkers.
This does cause some changes in the path notes for leak checkers. Previously,
a leak would be reported at the location of the closing brace in a function.
Now, it gets reported at the last statement. This matches the way leaks are
currently reported for inlined functions, but is less than ideal for both.
llvm-svn: 168066
We do this by using the "most recent" good location: if a synthesized
function 'A' calls another function 'B', the path notes for the call to 'B'
will be placed at the same location as the path note for calling 'A'.
Similarly, the call to 'A' will have a note saying "Entered call from...",
and now we just don't emit that (since the user doesn't have a body to look
at anyway).
Previously, we were doing this for the "Calling..." notes, but not for the
"Entered call from..." or "Returning to caller". This caused a crash when
the path entered and then exiting a call within a synthesized body.
<rdar://problem/12657843>
llvm-svn: 168019
conditions.
The adjustment is needed only in case of dynamic dispatch performed by
the analyzer - when the runtime declaration is different from the static
one.
Document this explicitly in the code (by adding a helper). Also, use
canonical Decls to avoid matching against the case where the definition
is different from found declaration.
This fix suppresses the testcase I added in r167762, so add another
testcase to make sure we do test commit r167762.
llvm-svn: 167780
Suppresses a leak false positive (radar://12663777).
In addition, we'll need to rewrite the adjustReturnValue() method not to
return UnknownVal by default, but rather assert in cases we cannot
handle. To make it possible, we need to correctly handle some of the
edge cases we already know about.
llvm-svn: 167762
Previously, RegionStore was being VERY conservative in saying that because
p[i].x and p[i].y have a concrete base region of 'p', they might overlap.
Now, we check the chain of fields back up to the base object and check if
they match.
This only kicks in when dealing with symbolic offset regions because
RegionStore's "base+offset" representation of concrete offset regions loses
all information about fields. In cases where all offsets are concrete
(s.x and s.y), RegionStore will already do the right thing, but mixing
concrete and symbolic offsets can cause bindings to be invalidated that
are known to not overlap (e.g. p[0].x and p[i].y).
This additional refinement is tracked by <rdar://problem/12676180>.
<rdar://problem/12530149>
llvm-svn: 167654
As Anna pointed out, ProgramStateTrait.h is a relatively obscure header,
and checker writers may not know to look there to add their own custom
state.
The base macro that specializes the template remains in ProgramStateTrait.h
(REGISTER_TRAIT_WITH_PROGRAMSTATE), which allows the analyzer core to keep
using it.
llvm-svn: 167385
This will simplify checkers that need to register for leaks. Currently,
they have to register for both: check dead and check end of path.
I've modified the SymbolReaper to consider everything on the stack dead
if the input StackLocationContext is 0.
(This is a bit disruptive, so I'd like to flash out all the issues
asap.)
llvm-svn: 167352
These are CallEvent-equivalents of helpers already accessible in
CheckerContext, as part of making it easier for new checkers to be written
using CallEvent rather than raw CallExprs.
llvm-svn: 167338
Also, move the REGISTER_*_WITH_PROGRAMSTATE macros to ProgramStateTrait.h.
This doesn't get rid of /all/ explicit uses of ProgramStatePartialTrait,
but it does get a lot of them.
llvm-svn: 167276
Previously, every call to a ConstraintManager's isNull would do a full
assumeDual to test feasibility. Now, ConstraintManagers can override
checkNull if they have a cheaper way to do the same thing.
RangeConstraintManager can do this in less than half the work.
<rdar://problem/12608209>
llvm-svn: 167138
Our one basic suppression heuristic is to assume that functions do not
usually return NULL. However, when one of the arguments is NULL it is
suddenly much more likely that NULL is a valid return value. In this case,
we don't suppress the report here, but we do attach /another/ visitor to
go find out if this NULL argument also comes from an inlined function's
error path.
This new behavior, controlled by the 'avoid-suppressing-null-argument-paths'
analyzer-config option, is turned off by default. Turning it on produced
two false positives and no new true positives when running over LLVM/Clang.
This is one of the possible refinements to our suppression heuristics.
<rdar://problem/12350829>
llvm-svn: 166941
Additionally, don't collect PostStore nodes -- they are often used in
path diagnostics.
Previously, we tried to track null arguments in the same way as any other
null values, but in many cases the necessary nodes had already been
collected (a memory optimization in ExplodedGraph). Now, we fall back to
using the value of the argument at the time of the call, which may not
always match the actual contents of the region, but often will.
This is a precursor to improving our suppression heuristic.
<rdar://problem/12350829>
llvm-svn: 166940
path notes for cases where a value may be assumed to be null, etc.
Instead of having redundant diagnostics, do a pass over the generated
PathDiagnostic pieces and remove notes from TrackConstraintBRVisitor
that are already covered by ConditionBRVisitor, whose notes tend
to be better.
Fixes <rdar://problem/12252783>
llvm-svn: 166728
After every 1000 CFGElements processed, the ExplodedGraph trims out nodes
that satisfy a number of criteria for being "boring" (single predecessor,
single successor, and more). Rather than controlling this with a cc1 option,
which can only disable this behavior, we now have an analyzer-config option,
'graph-trim-interval', which can change this interval from 1000 to something
else. Setting the value to 0 disables reclamation.
The next commit relies on this behavior to actually test anything.
llvm-svn: 166528
This is actually required by the C++ standard in
[basic.stc.dynamic.allocation]p3:
If an allocation function declared with a non-throwing
exception-specification fails to allocate storage, it shall return a
null pointer. Any other allocation function that fails to allocate
storage shall indicate failure only by throwing an exception of a type
that would match a handler of type std::bad_alloc.
We don't bother checking for the specific exception type, but just go off
the operator new prototype. This should help with a certain class of lazy
initalization false positives.
<rdar://problem/12115221>
llvm-svn: 166363
This actually looks through several kinds of expression, such as
OpaqueValueExpr and ExprWithCleanups. The idea is that binding and lookup
should be consistent, and so if the environment needs to be modified later,
the code doing the modification will not have to manually look through these
"transparent" expressions to find the real binding to change.
This is necessary for proper updating of struct rvalues as described in
the previous commit.
llvm-svn: 166121
In C++, rvalues that need to have their address taken (for example, to be
passed to a function by const reference) will be wrapped in a
MaterializeTemporaryExpr, which lets CodeGen know to create a temporary
region to store this value. However, MaterializeTemporaryExprs are /not/
created when a method is called on an rvalue struct, even though the 'this'
pointer needs a valid value. CodeGen works around this by creating a
temporary region anyway; now, so does the analyzer.
The analyzer also does this when accessing a field of a struct rvalue.
This is a little unfortunate, since the rest of the struct will soon be
thrown away, but it does make things consistent with the rest of the
analyzer.
This allows us to bring back the assumption that all known 'this' values
are Locs. This is a revised version of r164828-9, reverted in r164876-7.
<rdar://problem/12137950>
llvm-svn: 166120
This was only used by OSAtomicChecker and makes it more
difficult to update values for expressions that the environment
may look through instead (it's not the same as IgnoreParens).
With this gone, we can have bindExpr bind to the inner
expression that getSVal will find.
Groundwork for <rdar://problem/12137950>
llvm-svn: 165866
I believe the removed assert in CheckerManager says it best:
InlineCall is a special hacky callback to allow intrusive
evaluation of the call (which simulates inlining). It is
currently only used by OSAtomicChecker and should go away
at some point.
OSAtomicChecker has gone away; inlineCall can now go away as well!
llvm-svn: 165865
This time, actually uncomment the code that's supposed to fix the problem.
This reverts r165671 / 8ceb837585ed973dc36fba8dfc57ef60fc8f2735.
llvm-svn: 165676
Author: Jordan Rose <jordan_rose@apple.com>
Date: Wed Oct 10 21:31:21 2012 +0000
[analyzer] Treat fields of unions as having symbolic offsets.
This allows only one field to be active at a time in RegionStore.
This isn't quite the correct behavior for unions, but it at least
would handle the case of "value goes in, value comes out" from the
same field.
RegionStore currently has a number of places where any access to a union
results in UnknownVal being returned. However, it is clearly missing
some cases, or the original issue wouldn't have occurred. It is probably
now safe to remove those changes, but that's a potentially destabilizing
change that should wait for more thorough testing.
Fixes PR14054.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@165660 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit cf9030e480f77ab349672f00ad302e216c26c92c.
llvm-svn: 165671
This allows only one field to be active at a time in RegionStore.
This isn't quite the correct behavior for unions, but it at least
would handle the case of "value goes in, value comes out" from the
same field.
RegionStore currently has a number of places where any access to a union
results in UnknownVal being returned. However, it is clearly missing
some cases, or the original issue wouldn't have occurred. It is probably
now safe to remove those changes, but that's a potentially destabilizing
change that should wait for more thorough testing.
Fixes PR14054.
llvm-svn: 165660
Some implicit statements, such as the implicit 'self' inserted for "free"
Objective-C ivar access, have invalid source locations. If one of these
statements is the location where an issue is reported, we'll now look at
the enclosing statements for a valid source location.
<rdar://problem/12446776>
llvm-svn: 165354
In C++, overriding virtual methods are allowed to specify a covariant
return type -- that is, if the return type of the base method is an
object pointer type (or reference type), the overriding method's return
type can be a pointer to a subclass of the original type. The analyzer
was failing to take this into account when devirtualizing a method call,
and anything that relied on the return value having the proper type later
would crash.
In Objective-C, overriding methods are allowed to specify ANY return type,
meaning we can NEVER be sure that devirtualizing will give us a "safe"
return value. Of course, a program that does this will most likely crash
at runtime, but the analyzer at least shouldn't crash.
The solution is to check and see if the function/method being inlined is
the function that static binding would have picked. If not, check that
the return value has the same type. If the types don't match, see if we
can fix it with a derived-to-base cast (the C++ case). If we can't,
return UnknownVal to avoid crashing later.
<rdar://problem/12409977>
llvm-svn: 165079
These functions are store-agnostic, and would benefit from information in
DynamicTypeInfo but gain nothing from the store type.
No intended functionality change.
llvm-svn: 165078
table, making it printable with the ConfigDump checker. Along the
way, fix a really serious bug where the value was getting parsed
from the string in code that was in an assert() call. This means
in a Release-Asserts build this code wouldn't work as expected.
llvm-svn: 165041
By analogy with C structs, this seems to be legal, if probably discouraged.
It's only if the ivar is read from or written to that there's a problem.
Running a program that gets the "address" of an instance variable does in
fact return the offset when the base "object" is nil.
This isn't a full revert because r164442 includes some diagnostic tweaks
as well; those have been kept.
This partially reverts r164442 / 08965091770c9b276c238bac2f716eaa4da2dca4.
llvm-svn: 164960
The original intent of this commit was to catch potential null dereferences
early, but it breaks the common "home-grown offsetof" idiom (PR13927):
(((struct Foo *)0)->member - ((struct foo *)0))
As it turns out, this appears to be legal in C, per a footnote in
C11 6.5.3.2: "Thus, &*E is equivalent to E (even if E is a null pointer)".
In C++ this issue is still open:
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#232
We'll just have to make sure we have good path notes in the future.
This reverts r164441 / 9be016dcd1ca3986873a7b66bd4bc027309ceb59.
llvm-svn: 164958
string in the config table so that it can be dumped as part of the
config dumper. Add a test to show that these options are sticking
and can be cross-checked using FileCheck.
llvm-svn: 164954
This is related to but not blocked by <rdar://problem/12137950>
("Return-by-value structs do not have associated regions")
This reverts r164875 / 3278d41e17749dbedb204a81ef373499f10251d7.
llvm-svn: 164952
It is possible and valid to have a state manager and associated objects
without having a SubEngine or checkers.
Patch by Olaf Krzikalla!
llvm-svn: 164947
Previously the analyzer treated all inlined constructors like lvalues,
setting the value of the CXXConstructExpr to the newly-constructed
region. However, some CXXConstructExprs behave like rvalues -- in
particular, the implicit copy constructor into a pass-by-value argument.
In this case, we want only the /contents/ of a temporary object to be
passed, so that we can use the same "copy each argument into the
parameter region" algorithm that we use for scalar arguments.
This may change when we start modeling destructors of temporaries,
but for now this is the last part of <rdar://problem/12137950>.
llvm-svn: 164830
An rvalue has no address, but calling a C++ member function requires a
'this' pointer. This commit makes the analyzer create a temporary region
in which to store the struct rvalue and use as a 'this' pointer whenever
a member function is called on an rvalue, which is essentially what
CodeGen does.
More of <rdar://problem/12137950>. The last part is tracking down the
C++ FIXME in array-struct-region.cpp.
llvm-svn: 164829
Struct rvalues are represented in the analyzer by CompoundVals,
LazyCompoundVals, or plain ConjuredSymbols -- none of which have associated
regions. If the entire structure is going to persist, this is not a
problem -- either the rvalue will be assigned to an existing region, or
a MaterializeTemporaryExpr will be present to create a temporary region.
However, if we just need a field from the struct, we need to create the
temporary region ourselves.
This is inspired by the way CodeGen handles calls to temporaries;
support for that in the analyzer is coming next.
Part of <rdar://problem/12137950>
llvm-svn: 164828
Previously, we'd just keep constraints around forever, which means we'd
never be able to merge paths that differed only in constraints on dead
symbols.
Because we now allow constraints on symbolic expressions, not just single
symbols, this requires changing SymExpr::symbol_iterator to include
intermediate symbol nodes in its traversal, not just the SymbolData leaf
nodes.
This depends on the previous commit to be correct. Originally applied in
r163444, reverted in r164275, now being re-applied.
llvm-svn: 164622
No tests, but this allows the optimization of removing dead constraints.
We can then add tests that we don't do this prematurely.
<rdar://problem/12333297>
Note: the added FIXME to investigate SymbolRegionValue liveness is
tracked by <rdar://problem/12368183>. This patch does not change the
existing behavior.
llvm-svn: 164621
This is a heuristic intended to greatly reduce the number of false
positives resulting from inlining, particularly inlining of generic,
defensive C++ methods that live in header files. The suppression is
triggered in the cases where we ask to track where a null pointer came
from, and it turns out that the source of the null pointer was an inlined
function call.
This change brings the number of bug reports in LLVM from ~1500 down to
around ~300, a much more manageable number. Yes, some true positives may
be hidden as well, but from what I looked at the vast majority of silenced
reports are false positives, and many of the true issues found by the
analyzer are still reported.
I'm hoping to improve this heuristic further by adding some exceptions
next week (cases in which a bug should still be reported).
llvm-svn: 164449
Before, PathDiagnosticConsumers that did not support actual path output
would (sensibly) cause the generation of the full path to be skipped.
However, BugReporterVisitors may want to see the path in order to mark a
BugReport as invalid.
Now, even for a path generation scheme of 'None' we will still create a
trimmed graph and walk backwards through the bug path, doing no work other
than passing the nodes to the BugReporterVisitors. This isn't cheap, but
it's necessary to properly do suppression when the first path consumer does
not support path notes.
In the future, we should try only generating the path and visitor-provided
path notes once, or at least only creating the trimmed graph once.
llvm-svn: 164447
This is intended to allow visitors to make decisions about whether a
BugReport is likely a false positive. Currently there are no visitors
making use of this feature, so there are no tests.
When a BugReport is marked invalid, the invalidator must provide a key
that identifies the invaliation (intended to be the visitor type and a
context pointer of some kind). This allows us to reverse the decision
later on. Being able to reverse a decision about invalidation gives us more
flexibility, and allows us to formulate conditions like "this report is
invalid UNLESS the original argument is 'foo'". We can use this to
fine-tune our false-positive suppression (coming soon).
llvm-svn: 164446
Rather than saying "Null pointer value stored to 'foo'", we now say
"Passing null pointer value via Nth parameter 'foo'", which is much better.
The note is also now on the argument expression as well, rather than the
entire call.
This paves the way for continuing to track arguments back to their sources.
<rdar://problem/12211490>
llvm-svn: 164444
Like with struct fields, we want to catch cases like this early,
so that we can produce better diagnostics and path notes:
PointObj *p = nil;
int *px = &p->_x; // should warn here
*px = 1;
llvm-svn: 164442
We want to catch cases like this early, so that we can produce better
diagnostics and path notes:
Point *p = 0;
int *px = &p->x; // should warn here
*px = 1;
llvm-svn: 164441
their implementations are unavailable. Start by simulating dispatch_sync().
This change is largely a bunch of plumbing around something very simple. We
use AnalysisDeclContext to conjure up a fake function body (using the
current ASTContext) when one does not exist. This is controlled
under the analyzer-config option "faux-bodies", which is off by default.
The plumbing in this patch is largely to pass the necessary machinery
around. CallEvent needs the AnalysisDeclContextManager to get
the function definition, as one may get conjured up lazily.
BugReporter and PathDiagnosticLocation needed to be relaxed to handle
invalid locations, as the conjured body has no real source locations.
We do some primitive recovery in diagnostic generation to generate
some reasonable locations (for arrows and events), but it can be
improved.
llvm-svn: 164339
While we definitely want this optimization in the future, we're not
currently handling constraints on symbolic /expressions/ correctly.
These should stay live even if the SymExpr itself is no longer referenced
because could recreate an identical SymExpr later. Only once the SymExpr
can no longer be recreated -- i.e. a component symbol is dead -- can we
safely remove the constraints on it.
This liveness issue is tracked by <rdar://problem/12333297>.
This reverts r163444 / 24c7f98828e039005cff3bd847e7ab404a6a09f8.
llvm-svn: 164275
in ObjCMethods.
Extend FunctionTextRegion to represent ObjC methods as well as
functions. Note, it is not clear what type ObjCMethod region should
return. Since the type of the FunctionText region is not currently used,
defer solving this issue.
llvm-svn: 164046
in NSException to a helper object in libAnalysis that can also
be used by Sema. Not sure if the predicate name 'isImplicitNoReturn'
is the best one, but we can massage that later.
No functionality change.
llvm-svn: 163759
Again, GCC is more aggressive about reusing temporary space than we are,
leading to Release build crashes for this undefined behavior.
PR13710 (though it may not be the only problem there)
llvm-svn: 163747
Currently we don't update the dynamic type of a C++ object when it is
cast. This can cause the situation above, where the static type of the
region is now known to be a subclass of the dynamic type.
Once we start updating DynamicTypeInfo in response to the various kinds
of casts in C++, we can re-add this assert to make sure we don't miss
any cases. This work is tracked by <rdar://problem/12287087>.
In -Asserts builds, we will simply not return any runtime definition
when our DynamicTypeInfo is known to be incorrect like this.
llvm-svn: 163745
Using the static type may be inconsistent with later calls. We should just
report that there is no inlining definition available if the static type is
better than the dynamic type. See next commit.
This reverts r163644 / 19d5886d1704e24282c86217b09d5c6d35ba604d.
llvm-svn: 163744
While PR13724 is still an issue, it's not actually an issue in the STL.
We can keep this option around in case there turn out to be widespread
false positives due to poor modeling of the C++ standard library functions,
but for now we'd like to get more data.
This reverts r163633 / c6baadceec1d5148c20ee6c902a102233c547f62.
llvm-svn: 163647
reinterpret_cast does not provide any of the usual type information that
static_cast or dynamic_cast provide -- only the new type. This can get us
in a situation where the dynamic type info for an object is actually a
superclass of the static type, which does not match what CodeGen does at all.
In these cases, just fall back to the static type as the best possible type
for devirtualization.
Should fix the crashes on our internal buildbot.
llvm-svn: 163644
C++11 [expr.call]p1: ...If the selected function is non-virtual, or if the
id-expression in the class member access expression is a qualified-id,
that function is called. Otherwise, its final overrider in the dynamic type
of the object expression is called.
<rdar://problem/12255556>
llvm-svn: 163577
The option allows to always inline very small functions, whose size (in
number of basic blocks) is set using -analyzer-config
ipa-always-inline-size option.
llvm-svn: 163558
This is a (heavy-handed) solution to PR13724 -- until we know we can do
a good job inlining the STL, it's best to be consistent and not generate
more false positives than we did before. We can selectively whitelist
certain parts of the 'std' namespace that are known to be safe.
This is controlled by analyzer config option 'c++-stdlib-inlining', which
can be set to "true" or "false".
This commit also adds control for whether or not to inline any templated
functions (member or non-member), under the config option
'c++-template-inlining'. This option is currently on by default.
llvm-svn: 163548
I need to see how this breaks on other platforms when I fix the issue
that Benjamin Kramer pointed out.
This includes r163489 and r163490, plus a two line change.
llvm-svn: 163512
r163489, "Take another crack at stabilizing the emission order of analyzer"
r163490, "Use isBeforeInTranslationUnitThan() instead of operator<."
llvm-svn: 163497
diagnostics without using FoldingSetNodeIDs. This is done
by doing a complete recursive comparison of the PathDiagnostics.
Note that the previous method of comparing FoldingSetNodeIDs did
not end up relying on unstable things such as pointer addresses, so
I suspect this may still have some issues on various buildbots because
I'm not sure if the true source of non-determinism has been eliminated.
The tests pass for me, so the only way to know is to commit this change
and see what happens.
llvm-svn: 163489
ObjCSelfInitChecker stashes information in the GDM to persist it across
function calls; it is stored in pre-call checks and retrieved post-call.
The post-call check is supposed to clear out the stored state, but was
failing to do so in cases where the call did not have a symbolic return
value.
This was actually causing the inappropriate cache-out from r163361.
Per discussion with Anna, we should never actually cache out when
assuming the receiver of an Objective-C message is non-nil, because
we guarded that node generation by checking that the state has changed.
Therefore, the only states that could reach this exact ExplodedNode are
ones that should have merged /before/ making this assumption.
r163361 has been reverted and the test case removed, since it won't
actually test anything interesting now.
llvm-svn: 163449
Previously, we'd just keep constraints around forever, which means we'd
never be able to merge paths that differed only in constraints on dead
symbols.
Because we now allow constraints on symbolic expressions, not just single
symbols, this requires changing SymExpr::symbol_iterator to include
intermediate symbol nodes in its traversal, not just the SymbolData leaf
nodes.
llvm-svn: 163444
RegionStoreManager was only treating a SymbolicRegion's symbel as live
if there was a binding referring to the region itself.
No test case because constraints are currently not being cleaned out
of the constraint manager at all (even if the symbol is legitimately dead).
llvm-svn: 163443
This is necessary because further analysis will assume that the SVal's
type matches the AST type. This caused a crash when trying to perform
a derived-to-base cast on a C++ object that had been new'd to be another
object type.
Yet another crash in PR13763.
llvm-svn: 163442
with at least one subtle bug in MacOSXKeyChainAPIChecker where the
calling the method was a substitute for assuming a symbolic value
was null (which is not the case).
We still keep ConstraintManager::getSymVal(), but we use that as
an optimization in SValBuilder and ProgramState::getSVal() to
constant-fold SVals. This is only if the ConstraintManager can
provide us with that information, which is no longer a requirement.
As part of this, introduce a default implementation of
ConstraintManager::getSymVal() which returns null.
For Checkers, introduce ConstraintManager::isNull(), which queries
the state to see if the symbolic value is constrained to be a null
value. It does this without assuming it has been implicitly constant
folded.
llvm-svn: 163428
When adding the next statement to the CoreEngine's work list, we take care
of all the special cases first. We certainly shouldn't be building
PostStmts with null statements (the diagnostics machinery assumes such
StmtPoints do not exist), and we should find out sooner if we're missing
a special case.
A refinement of r163402 that should help prevent further issues like PR13760.
llvm-svn: 163409
GCC destroys temporary objects more aggressively than clang, so this
results in incorrect behavior when compiling GCC Release builds.
We could avoid this issue under C++11 by preventing getAs from being
called when 'this' is an rvalue:
template<class ElemTy> const ElemTy *getAs() const & { ... }
template<class ElemTy> const ElemTy *getAs() const && = delete;
Unfortunately, we do not have compatibility macros for this behavior yet.
This will hopefully fix PR13760 and PR13762.
llvm-svn: 163402
(as this previously was the case before this was refactored). We also shouldn't
need to specially handle BinaryOperators since the eagerly-assume heuristic tags
such nodes.
llvm-svn: 163374
implicit pointer-to-boolean conversions in condition expressions. This would
result in inconsistent diagnostic emission between C and C++.
A consequence of this is now ConditionBRVisitor and TrackConstraintBRVisitor may
emit redundant diagnostics, for example:
"Assuming pointer value is null" (TrackConstraintBRVisitor)
"Assuming 'p' is null" (ConditionBRVisitor)
We need to reconcile the two, and perhaps prefer one over the other in some
cases.
llvm-svn: 163372
With some particularly evil casts, we can get an object whose dynamic type
is not actually a subclass of its static type. In this case, we won't even
find the statically-resolved method as a devirtualization candidate.
Rather than assert that this situation cannot occur, we now simply check
that the dynamic type is not an ancestor or descendent of the static type,
and leave it at that.
This error actually occurred analyzing LLVM: CallEventManager uses a
BumpPtrAllocator to allocate a concrete subclass of CallEvent
(FunctionCall), but then casts it to the actual subclass requested
(such as ObjCMethodCall) to perform the constructor.
Yet another crash in PR13763.
llvm-svn: 163367
A bizarre series of coincidences led us to generate a previously-seen
node in the middle of processing an Objective-C message, where we assume
the receiver is non-nil. We were assuming that such an assumption would
never "cache out" like this, and blithely went on using a null ExplodedNode
as the predecessor for the next step in evaluation.
Although the test case committed here is complicated, this could in theory
happen in other ways as well, so the correct fix is just to test if the
non-nil assumption results in an ExplodedNode we've seen before.
<rdar://problem/12243648>
llvm-svn: 163361
CXXDestructorCall now has a flag for when it is a base destructor call.
Other kinds of destructor calls (locals, fields, temporaries, and 'delete')
all behave as "whole-object" destructors and do not behave differently
from one another (specifically, in these cases we /should/ try to
devirtualize a call to a virtual destructor).
This was causing crashes in both our internal buildbot, the crash still
being tracked in PR13765, and some of the crashes being tracked in PR13763,
due to a assertion failure. (The behavior under -Asserts happened to be
correct anyway.)
Adding this knowledge also allows our DynamicTypePropagation checker to do
a bit less work; the special rules about virtual method calls during a
destructor only require extra handling during base destructors.
llvm-svn: 163348
While destructors will continue to not be inlined (unless the analyzer
config option 'c++-inlining' is set to 'destructors'), leaving them out
of the CFG is an incomplete model of the behavior of an object, and
can cause false positive warnings (like PR13751, now working).
Destructors for temporaries are still not on by default, since
(a) we haven't actually checked this code to be sure it's fully correct
(in particular, we probably need to be very careful with regard to
lifetime-extension when a temporary is bound to a reference,
C++11 [class.temporary]p5), and
(b) ExprEngine doesn't actually do anything when it sees a temporary
destructor in the CFG -- not even invalidate the object region.
To enable temporary destructors, set the 'cfg-temporary-dtors' analyzer
config option to '1'. The old -cfg-add-implicit-dtors cc1 option, which
controlled all implicit destructors, has been removed.
llvm-svn: 163264
If a region is binded to a symbolic value, we should track the symbol.
(The code I changed was not previously exercised by the regression
tests.)
llvm-svn: 163261
The problem is that the value of 'this' in a C++ member function call
should always be a region (or NULL). However, if the object is an rvalue,
it has no associated region (only a conjured symbol or LazyCompoundVal).
For now, we handle this in two ways:
1) Actually respect MaterializeTemporaryExpr. Before, it was relying on
CXXConstructExpr to create temporary regions for all struct values.
Now it just does the right thing: if the value is not in a temporary
region, create one.
2) Have CallEvent recognize the case where its 'this' pointer is a
non-region, and just return UnknownVal to keep from confusing clients.
The long-term problem is being tracked internally in <rdar://problem/12137950>,
but this makes many test cases pass.
llvm-svn: 163220
This turned out to have many implications, but what eventually seemed to
make it unworkable was the fact that we can get struct values (as
LazyCompoundVals) from other places besides return-by-value function calls;
that is, we weren't actually able to "treat all struct values as regions"
consistently across the entire analyzer core.
Hopefully we'll be able to come up with an alternate solution soon.
This reverts r163066 / 02df4f0aef142f00d4637cd851e54da2a123ca8e.
llvm-svn: 163218
SimpleSValBuilder processes a couple trivial identities, including 'x - x'
and 'x ^ x' (both 0). However, the former could appear with arguments of
floating-point type, and we weren't checking for that. This started
triggering an assert with r163069, which checks that a constant value is
actually going to be used as an integer or pointer.
llvm-svn: 163159
All clients of BasicValueFactory should be using QualTypes instead, and
indeed it seems they are. This caught the (fortunately harmless) bug
fixed in the previous commit.
No intended functionality change.
llvm-svn: 163069
The current logic would actually create a float- or double-sized signed
integer value of 1, which is not at all the same.
No test because the value would be swallowed by an Unknown as soon as it
gets added or subtracted to the original value, but it enables the cleanup
in the next patch.
llvm-svn: 163068
This allows us to correctly symbolicate the fields of structs returned by
value, as well as get the proper 'this' value for when methods are called
on structs returned by value.
This does require a moderately ugly hack in the StoreManager: if we assign
a "struct value" to a struct region, that now appears as a Loc value being
bound to a region of struct type. We handle this by simply "dereferencing"
the struct value region, which should create a LazyCompoundVal.
This should fix recent crashes analyzing LLVM and on our internal buildbot.
<rdar://problem/12137950>
llvm-svn: 163066
Previously, we preferred to get a result type by looking at the callee's
declared result type. This allowed us to handlereferences, which are
represented in the AST as lvalues of their pointee type. (That is, a call
to a function returning 'int &' has type 'int' and value kind 'lvalue'.)
However, this results in us preferring the original type of a function
over a casted type. This is a problem when a function pointer is casted
to another type, because the conjured result value will have the wrong
type. AdjustedReturnValueChecker is supposed to handle this, but still
doesn't handle the case where there is no "original function" at all,
i.e. where the callee is unknown.
Now, we instead look at the call expression's value kind (lvalue, xvalue,
or prvalue), and adjust the expr's type accordingly. This will have no
effect when the function is inlined, and will conjure the value that will
actually be used when it is not.
This makes AdjustedReturnValueChecker /nearly/ unnecessary; unfortunately,
the cases where it would still be useful are where we need to cast the
result of an inlined function or a checker-evaluated function, and in these
cases we don't know what we're casting /from/ by the time we can do post-
call checks. In light of that, remove AdjustedReturnValueChecker, which
was already not checking quite a few calls.
llvm-svn: 163065
Anna Zaks