See https://code.google.com/p/address-sanitizer/issues/detail?id=299 for the
original feature request.
Introduce llvm.asan.globals metadata, which Clang (or any other frontend)
may use to report extra information about global variables to ASan
instrumentation pass in the backend. This metadata replaces
llvm.asan.dynamically_initialized_globals that was used to detect init-order
bugs. llvm.asan.globals contains the following data for each global:
1) source location (file/line/column info);
2) whether it is dynamically initialized;
3) whether it is blacklisted (shouldn't be instrumented).
Source location data is then emitted in the binary and can be picked up
by ASan runtime in case it needs to print error report involving some global.
For example:
0x... is located 4 bytes to the right of global variable 'C::array' defined in '/path/to/file:17:8' (0x...) of size 40
These source locations are printed even if the binary doesn't have any
debug info.
This is an ABI-breaking change. ASan initialization is renamed to
__asan_init_v4(). Pre-built libraries compiled with older Clang will not work
with the fresh runtime.
llvm-svn: 212188
The former used to crash with a null deref if it was given a not owned pointer,
while the latter returned 0. Now they both return 0. This is still not the best possible
behavior: it is better to print an error report with a stack trace, pointing
to the error in user code, as we do in ASan.
llvm-svn: 212112
Origin history should only be recorded for uninitialized values, because it is
meaningless otherwise. This change moves __msan_chain_origin to the runtime
library side and makes it conditional on the corresponding shadow value.
Previous code was correct, but _very_ inefficient.
llvm-svn: 211700
Summary: The patch supports both the clang cross-compiler and native compiler
Patch by Kumar Sukhani <Kumar.Sukhani@imgtec.com>
Test Plan:
Kumar had the following asan test results when compiled on a MIPS board:
Expected Passes : 96
Expected Failures : 2
Unsupported Tests : 84
Unexpected Passes : 4
Unexpected Failures: 19
The list of unexpected failures can be found in the review.
Reviewers: kcc, petarj, dsanders
Reviewed By: kcc
Subscribers: farazs, kcc, llvm-commits
Differential Revision: http://reviews.llvm.org/D4208
llvm-svn: 211587
Storage Class 3 is static storage. These symbols need to be marked as external
(storage class 2) so that they can be referenced. Note that this external is
not the same as ELF "external" visibility, which is indicated by DLL Storage
Class (i.e. __declspec(dllexport) or __declspec(dllimport)).
llvm-svn: 211428
Add a test for the frexp() interceptor.
Annotate the interceptors that may potentially corrupt stack IDs of freed buffers with FIXME comments.
llvm-svn: 211153
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
When possible, use Thumb or Thumb-2 over ARM instructions. This is particularly
important for pure-Thumb environments (e.g. Windows on ARM). Although, it is
possible to conditionalise this for that target specifically, this is available
on most newer ARM CPUs, and the code remains compatible with older CPUs with no
adverse effects. It therefore feels better to always prefer Thumb when
possible.
llvm-svn: 211032
Init-order and use-after-return modes can currently be enabled
by runtime flags. use-after-scope mode is not really working at the
moment.
The only problem I see is that users won't be able to disable extra
instrumentation for init-order and use-after-scope by a top-level Clang flag.
But this instrumentation was implicitly enabled for quite a while and
we didn't hear from users hurt by it.
llvm-svn: 210924
Alexey Samsonov