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
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
This commit adds a weak variant of the cmpxchg operation, as described
in C++11. A cmpxchg instruction with this modifier is permitted to
fail to store, even if the comparison indicated it should.
As a result, cmpxchg instructions must return a flag indicating
success in addition to their original iN value loaded. Thus, for
uniformity *all* cmpxchg instructions now return "{ iN, i1 }". The
second flag is 1 when the store succeeded.
At the DAG level, a new ATOMIC_CMP_SWAP_WITH_SUCCESS node has been
added as the natural representation for the new cmpxchg instructions.
It is a strong cmpxchg.
By default this gets Expanded to the existing ATOMIC_CMP_SWAP during
Legalization, so existing backends should see no change in behaviour.
If they wish to deal with the enhanced node instead, they can call
setOperationAction on it. Beware: as a node with 2 results, it cannot
be selected from TableGen.
Currently, no use is made of the extra information provided in this
patch. Test updates are almost entirely adapting the input IR to the
new scheme.
Summary for out of tree users:
------------------------------
+ Legacy Bitcode files are upgraded during read.
+ Legacy assembly IR files will be invalid.
+ Front-ends must adapt to different type for "cmpxchg".
+ Backends should be unaffected by default.
llvm-svn: 210903
This flag replaces inline instrumentation for checks and origin stores with
calls into MSan runtime library. This is a workaround for PR17409.
Disabled by default.
llvm-svn: 206585
LLVM 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: 204151
The syntax for "cmpxchg" should now look something like:
cmpxchg i32* %addr, i32 42, i32 3 acquire monotonic
where the second ordering argument gives the required semantics in the case
that no exchange takes place. It should be no stronger than the first ordering
constraint and cannot be either "release" or "acq_rel" (since no store will
have taken place).
rdar://problem/15996804
llvm-svn: 203559
Currently SplitBlockAndInsertIfThen requires that branch condition is an
Instruction itself, which is very inconvenient, because it is sometimes an
Operator, or even a Constant.
llvm-svn: 197677
Indirect call wrapping helps MSanDR (dynamic instrumentation companion tool
for MSan) to catch all cases where execution leaves a compiler-instrumented
module by allowing the tool to rewrite targets of indirect calls.
This change is an optimization that skips wrapping for calls when target is
inside the current module. This relies on the linker providing symbols at the
begin and end of the module code (or code + data, does not really matter).
Gold linker provides such symbols by default. GNU (BFD) linker needs a link
flag: -Wl,--defsym=__executable_start=0.
More info:
https://code.google.com/p/memory-sanitizer/wiki/MSanDR#Native_exec
llvm-svn: 194697
Currently MSan checks that arguments of *cvt* intrinsics are fully initialized.
That's too much to ask: some of them only operate on lower half, or even
quarter, of the input register.
llvm-svn: 192599
Adds a flag to the MemorySanitizer pass that enables runtime rewriting of
indirect calls. This is part of MSanDR implementation and is needed to return
control to the DynamiRio-based helper tool on transition between instrumented
and non-instrumented modules. Disabled by default.
llvm-svn: 191006
Select condition shadow was being ignored resulting in false negatives.
This change OR-s sign-extended condition shadow into the result shadow.
llvm-svn: 189785
The code was erroneously reading overflow area shadow from the TLS slot,
bypassing the local copy. Reading shadow directly from TLS is wrong, because
it can be overwritten by a nested vararg call, if that happens before va_start.
llvm-svn: 189104
- Instead of setting the suffixes in a bunch of places, just set one master
list in the top-level config. We now only modify the suffix list in a few
suites that have one particular unique suffix (.ml, .mc, .yaml, .td, .py).
- Aside from removing the need for a bunch of lit.local.cfg files, this enables
4 tests that were inadvertently being skipped (one in
Transforms/BranchFolding, a .s file each in DebugInfo/AArch64 and
CodeGen/PowerPC, and one in CodeGen/SI which is now failing and has been
XFAILED).
- This commit also fixes a bunch of config files to use config.root instead of
older copy-pasted code.
llvm-svn: 188513
Before this change, each module defined a weak_odr global __msan_track_origins
with a value of 1 if origin tracking is enabled, 0 if disabled. If there are
modules with different values, any of them may win. If 0 wins, and there is at
least one module with 1, the program will most likely crash.
With this change, __msan_track_origins is only emitted if origin tracking is
on. Then runtime library detects if there is at least one module with origin
tracking, and enables runtime support for it.
llvm-svn: 182997
Shadow checks are disabled and memory loads always produce fully initialized
values in functions that don't have a sanitize_memory attribute. Value and
argument shadow is propagated as usual.
This change also updates blacklist behaviour to match the above.
llvm-svn: 176247
It is way too slow. Change the default option value to 0.
Always do exact shadow propagation for unsigned ICmp with constants, it is
cheap (under 1% cpu time) and required for correctness.
llvm-svn: 173682
Only for integers, pointers, and vectors of those. No floats.
Instrumentation seems very heavy, and may need to be replaced
with some approximation in the future.
llvm-svn: 173452
This fixes va_start/va_copy of a va_list field which happens to not
be laid out at a 16-byte boundary.
Differential Revision: http://llvm-reviews.chandlerc.com/D276
llvm-svn: 172128
