Multiplication by an integer with a number of trailing zero bits leaves
the same number of lower bits of the result initialized to zero.
This change makes MSan take this into account in the case of multiplication by
a compile-time constant.
We don't handle the general, non-constant, case because
(a) it's not going to be cheap (computation-wise);
(b) multiplication by a partially uninitialized value in user code is
a bad idea anyway.
Constant case must be handled because it appears from LLVM optimization of a
completely valid user code, as the test case in compiler-rt demonstrates.
llvm-svn: 211092
Instructions from __nodebug__ functions don't have file:line
information even when inlined into no-nodebug functions. As a result,
intrinsics (SSE and other) from <*intrin.h> clang headers _never_
have file:line information.
With this change, an instruction without !dbg metadata gets one from
the call instruction when inlined.
Fixes PR19001.
llvm-svn: 210459
Generalize StackDepot and create a new specialized instance of it to
efficiently (i.e. without duplicating stack trace data) store the
origin history tree.
This reduces memory usage for chained origins roughly by an order of
magnitude.
Most importantly, this new design allows us to put two limits on
stored history data (exposed in MSAN_OPTIONS) that help avoid
exponential growth in used memory on certain workloads.
See comments in lib/msan/msan_origin.h for more details.
llvm-svn: 209284
Move fflush and fclose interceptors to sanitizer_common.
Use a metadata map to keep information about the external locations
that must be updated when the file is written to.
llvm-svn: 208676
If printf is intercepted (it is not atm), REAL(printf) call in the interceptor
would get redirected back to my_lgamma, resulting in infinite recursion.
llvm-svn: 208294
Using __msan_unpoison() on null-terminated strings is awkward because
strlen() can't be called on a poisoned string. This case warrants a special
interface function.
llvm-svn: 204448
Compiler-rt part of MSan implementation of advanced origin tracking,
when we record not only creation point, but all locations where
an uninitialized value was stored to memory, too.
llvm-svn: 204152
Evgeniy Stepanov