This commits sets the grounds for more aggressive use after free
checking. We will use the Relinquished sate to denote that someone
else is now responsible for releasing the memory.
llvm-svn: 158850
Specifically, although the bitmap context does not take ownership of the
buffer (unlike CGBitmapContextCreateWithData), the data buffer can be extracted
out of the created CGContextRef. Thus the buffer is not leaked even if its
original pointer goes out of scope, as long as
- the context escapes, or
- it is retrieved via CGBitmapContextGetData and freed.
Actually implementing that logic is beyond the current scope of MallocChecker,
so for now CGBitmapContextCreate goes on our system function exception list.
llvm-svn: 158579
Add a concept of symbolic memory region belonging to heap memory space.
When comparing symbolic regions allocated on the heap, assume that they
do not alias.
Use symbolic heap region to suppress a common false positive pattern in
the malloc checker, in code that relies on malloc not returning the
memory aliased to other malloc allocations, stack.
llvm-svn: 158136
We report a leak at a point a leaked variable is no longer accessible.
The statement that happens to be at that point is not relevant to the
leak diagnostic and, thus, should not be highlighted.
radar://11178519
llvm-svn: 156530
(Applied changes to CStringAPI, Malloc, and Taint.)
This might almost never happen, but we should not crash even if it does.
This fixes a crash on the internal analyzer buildbot, where postgresql's
configure was redefining memmove (radar://11219852).
llvm-svn: 154451
Fixes a false positive (radar://11152419). The current solution of
adding the info into 3 places is quite ugly. Pending a generic pointer
escapes callback.
llvm-svn: 153731
This required adding a change count token to BugReport, but also allowed us to ditch ImmutableList as the BugReporterVisitor data type.
Also, remove the hack from MallocChecker, now that visitors appear in the opposite order. This is not exactly a fix, but the common case -- custom diagnostics after generic ones -- is now the default behavior.
llvm-svn: 153369
Specifically, we use the last store of the leaked symbol in the leak diagnostic.
(No support for struct fields since the malloc checker doesn't track those
yet.)
+ Infrastructure to track the regions used in store evaluations.
This approach is more precise than iterating the store to
obtain the region bound to the symbol, which is used in RetainCount
checker. The region corresponds to what is uttered in the code in the
last store and we do not rely on the store implementation to support
this functionality.
llvm-svn: 153212
This is accomplished by calling markInteresting /during/ path diagnostic generation, and as such relies on deterministic ordering of BugReporterVisitors -- namely, that BugReporterVisitors are run in /reverse/ order from how they are added. (Right now that's a consequence of storing visitors in an ImmutableList, where new items are added to the front.) It's a little hacky, but it works for now.
I think this is the best we can do without storing the relation between the old and new symbols, and that would be a hit whether or not there ends up being an error.
llvm-svn: 153010
The symbol-aware stack hint combines the checker-provided message
with the information about how the symbol was passed to the callee: as
a parameter or a return value.
For malloc, the generated messages look like this :
"Returning from 'foo'; released memory via 1st parameter"
"Returning from 'foo'; allocated memory via 1st parameter"
"Returning from 'foo'; allocated memory returned"
"Returning from 'foo'; reallocation of 1st parameter failed"
(We are yet to handle cases when the symbol is a field in a struct or
an array element.)
llvm-svn: 152962
BugVisitor DiagnosticPieces.
When checkers create a DiagnosticPieceEvent, they can supply an extra
string, which will be concatenated with the call exit message for every
call on the stack between the diagnostic event and the final bug report.
(This is a simple version, which could be/will be further enhanced.)
For example, this is used in Malloc checker to produce the ",
which allocated memory" in the following example:
static char *malloc_wrapper() { // 2. Entered call from 'use'
return malloc(12); // 3. Memory is allocated
}
void use() {
char *v;
v = malloc_wrapper(); // 1. Calling 'malloc_wrappers'
// 4. Returning from 'malloc_wrapper', which allocated memory
} // 5. Memory is never released; potential
memory leak
llvm-svn: 152837
Essentially, a bug centers around a story for various symbols and regions. We should only include
the path diagnostic events that relate to those symbols and regions.
The pruning is done by associating a set of interesting symbols and regions with a BugReporter, which
can be modified at BugReport creation or by BugReporterVisitors.
This patch reduces the diagnostics emitted in several of our test cases. I've vetted these as
having desired behavior. The only regression is a missing null check diagnostic for the return
value of realloc() in test/Analysis/malloc-plist.c. This will require some investigation to fix,
and I have added a FIXME to the test case.
llvm-svn: 152361
funopen, setvbuf.
Teach the checker and the engine about these APIs to resolve malloc
false positives. As I am adding more of these APIs, it is clear that all
this should be factored out into a separate callback (for example,
region escapes). Malloc, KeyChainAPI and RetainRelease checkers could
all use it.
llvm-svn: 151737
When allocated buffer is passed to CF/NS..NoCopy functions, the
ownership is transfered unless the deallocator argument is set to
'kCFAllocatorNull'.
llvm-svn: 151608
Assume none of the ObjC messages defined in system headers free memory,
except for the ones containing 'freeWhenDone' selector. Currently, just
assume that the region escapes to the messages with 'freeWhenDone'
(ideally, we want to treat it as 'free()').
For now, always assume that regions escape when passed to C++ methods.
llvm-svn: 151410
When we find two leak reports with the same allocation site, report only
one of them.
Provide a helper method to BugReporter to facilitate this.
llvm-svn: 151287
Make this call an exception in ExprEngine::invalidateArguments:
'int pthread_setspecific(ptheread_key k, const void *)' stores
a value into thread local storage. The value can later be retrieved
with 'void *ptheread_getspecific(pthread_key)'. So even thought the
parameter is 'const void *', the region escapes through the
call.
(Here we just blacklist the call in the ExprEngine's default
logic. Another option would be to add a checker which evaluates
the call and triggers the call to invalidate regions.)
Teach the Malloc Checker, which treats all system calls as safe about
the API.
llvm-svn: 151220
- We should not evaluate strdup in the Malloc Checker, it's the job of
CString checker, so just update the RefState to reflect allocated
memory.
- Refactor to reduce LOC: remove some wrapper auxiliary functions, make
all functions return the state and add the transition in one place
(instead of in each auxiliary function).
llvm-svn: 151188
it aware of CString APIs that return the input parameter.
Malloc Checker needs to know how the 'strcpy' function is
evaluated. Introduce the dependency on CStringChecker for that.
CStringChecker knows all about these APIs.
Addresses radar://10864450
llvm-svn: 150846
We are not properly handling the memory regions that escape into struct
fields, which led to a bunch of false positives. Be conservative here
and give up when a pointer escapes into a struct.
llvm-svn: 150658
(In response of Ted's review of r150112.)
This moves the logic which checked if a symbol escapes through a
parameter to invalidateRegionCallback (instead of post CallExpr visit.)
To accommodate the change, added a CallOrObjCMessage parameter to
checkRegionChanges callback.
llvm-svn: 150513
in realloc map.
If there is no dependency, the reallocated ptr will get garbage
collected before we know that realloc failed, which would lead us to
missing a memory leak warning.
Also added new test cases, which we can handle now.
Plus minor cleanups.
llvm-svn: 150446
Anna Zaks