Summary:
The following code snippet taken from D64271#1572188 has an issue: namely,
because `flag`'s value isn't undef or a concrete int, it isn't being tracked.
int flag;
bool coin();
void foo() {
flag = coin();
}
void test() {
int *x = 0;
int local_flag;
flag = 1;
foo();
local_flag = flag;
if (local_flag)
x = new int;
foo();
local_flag = flag;
if (local_flag)
*x = 5;
}
This, in my opinion, makes no sense, other values may be interesting too.
Originally added by rC185608.
Differential Revision: https://reviews.llvm.org/D64287
llvm-svn: 368773
Tracking those can help to provide much better diagnostics in many cases.
In general, most of the visitor machinery should be refactored to allow
tracking the origin of arbitrary values.
rdar://36039765
Differential Revision: https://reviews.llvm.org/D51131
llvm-svn: 340475
In order to provide more test coverage for inlined operator new(), add more
run-lines to existing test cases, which would trigger our fake header
to provide a body for operator new(). Most of the code should still behave
reasonably. When behavior intentionally changes, #ifs are provided.
Differential Revision: https://reviews.llvm.org/D42221
llvm-svn: 323376
When trying to figure out where a null or undefined value came from,
parentheses and cast expressions are either completely irrelevant, or,
in the case of lvalue-to-rvale cast, straightforwardly lead us in the right
direction when we remove them.
There is a regression that causes a certain diagnostic to appear twice in the
path-notes.cpp test (changed to FIXME). It would be addressed in the next
commit.
Differential revision: https://reviews.llvm.org/D41254
llvm-svn: 321133
Null dereferences are suppressed if the lvalue was constrained to 0 for the
first time inside a sub-function that was inlined during analysis, because
such constraint is a valid defensive check that does not, by itself,
indicate that null pointer case is anyhow special for the caller.
If further operations on the lvalue are performed, the symbolic lvalue is
collapsed to concrete null pointer, and we need to track where does the null
pointer come from.
Improve such tracking for lvalue operations involving operator &.
rdar://problem/27876009
Differential Revision: https://reviews.llvm.org/D31982
llvm-svn: 301224
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
Kristof Umann