Due to improper modelling of copy constructors (specifically, their
const reference arguments), we were producing spurious leak warnings
for allocated memory stored in structs. In order to silence this, we
decided to consider storing into a struct to be the same as escaping.
However, the previous commit has fixed this issue and we can now properly
distinguish leaked memory that happens to be in a struct from a buffer
that escapes within a struct wrapper.
Originally applied in r161511, reverted in r174468.
<rdar://problem/12945937>
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177571 91177308-0d34-0410-b5e6-96231b3b80d8
This is a "quick fix".
The underlining issue is that when a const pointer to a struct is passed
into a function, we do not invalidate the pointer fields. This results
in false positives that are common in C++ (since copy constructors are
prevalent). (Silences two llvm false positives.)
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174468 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@168070 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes several issues:
- removes egregious hack where PlistDiagnosticConsumer would forward to HTMLDiagnosticConsumer,
but diagnostics wouldn't be generated consistently in the same way if PlistDiagnosticConsumer
was used by itself.
- emitting diagnostics to the terminal (using clang's diagnostic machinery) is no longer a special
case, just another PathDiagnosticConsumer. This also magically resolved some duplicate warnings,
as we now use PathDiagnosticConsumer's diagnostic pruning, which has scope for the entire translation
unit, not just the scope of a BugReporter (which is limited to a particular ExprEngine).
As an interesting side-effect, diagnostics emitted to the terminal also have their trailing "." stripped,
just like with diagnostics emitted to plists and HTML. This required some tests to be updated, but now
the tests have higher fidelity with what users will see.
There are some inefficiencies in this patch. We currently generate the report graph (from the ExplodedGraph)
once per PathDiagnosticConsumer, which is a bit wasteful, but that could be pulled up higher in the
logic stack. There is some intended duplication, however, as we now generate different PathDiagnostics (for the same issue)
for different PathDiagnosticConsumers. This is necessary to produce the diagnostics that a particular
consumer expects.
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The main blocker on this (besides the previous commit) was that
ScanReachableSymbols was not looking through LazyCompoundVals.
Once that was fixed, it's easy enough to clear out malloc data on return,
just like we do when we bind to a global region.
<rdar://problem/10872635>
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161511 91177308-0d34-0410-b5e6-96231b3b80d8
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.
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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.
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attributes, introduced in r151188.
+ the test to catch it.
Thanks to Ahmed Charles for pointing this out.
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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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150658 91177308-0d34-0410-b5e6-96231b3b80d8
memory.
(As per one test case, the existing checker thought that this could
cause a lot of false positives - not sure if that's valid, to be
verified.)
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optimistic.
TODO: actually implement the pessimistic version of the checker. Ex: it
needs to assume that any function that takes a pointer might free it.
The optimistic version relies on annotations to tell us which functions
can free the pointer.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150111 91177308-0d34-0410-b5e6-96231b3b80d8
Dominic Chen