| ecadc219 | 29-Jul-2019 |
Dimitry Andric <[email protected]> |
MFC r350362:
Pull in r366369 from upstream llvm trunk (by Francis Visoiu Mistrih):
[CodeGen][NFC] Simplify checks for stack protector index checking
Use `hasStackProtectorIndex()` instead of `
MFC r350362:
Pull in r366369 from upstream llvm trunk (by Francis Visoiu Mistrih):
[CodeGen][NFC] Simplify checks for stack protector index checking
Use `hasStackProtectorIndex()` instead of `getStackProtectorIndex()
>= 0`.
Pull in r366371 from upstream llvm trunk (by Francis Visoiu Mistrih):
[PEI] Don't re-allocate a pre-allocated stack protector slot
The LocalStackSlotPass pre-allocates a stack protector and makes sure
that it comes before the local variables on the stack.
We need to make sure that later during PEI we don't re-allocate a new
stack protector slot. If that happens, the new stack protector slot
will end up being **after** the local variables that it should be
protecting.
Therefore, we would have two slots assigned for two different stack
protectors, one at the top of the stack, and one at the bottom. Since
PEI will overwrite the assigned slot for the stack protector, the
load that is used to compare the value of the stack protector will
use the slot assigned by PEI, which is wrong.
For this, we need to check if the object is pre-allocated, and re-use
that pre-allocated slot.
Differential Revision: https://reviews.llvm.org/D64757
Pull in r367068 from upstream llvm trunk (by Francis Visoiu Mistrih):
[CodeGen] Don't resolve the stack protector frame accesses until PEI
Currently, stack protector loads and stores are resolved during
LocalStackSlotAllocation (if the pass needs to run). When this is the
case, the base register assigned to the frame access is going to be
one of the vregs created during LocalStackSlotAllocation. This means
that we are keeping a pointer to the stack protector slot, and we're
using this pointer to load and store to it.
In case register pressure goes up, we may end up spilling this
pointer to the stack, which can be a security concern.
Instead, leave it to PEI to resolve the frame accesses. In order to
do that, we make all stack protector accesses go through frame index
operands, then PEI will resolve this using an offset from sp/fp/bp.
Differential Revision: https://reviews.llvm.org/D64759
Together, these fix a issue where the stack protection feature in LLVM's
ARM backend can be rendered ineffective when the stack protector slot is
re-allocated so that it appears after the local variables that it is
meant to protect, leaving the function potentially vulnerable to a
stack-based buffer overflow.
Reported by: andrew
Security: https://kb.cert.org/vuls/id/129209/
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| 85573313 | 23-Jul-2019 |
Dimitry Andric <[email protected]> |
MFC r348504 (by kevans):
llvm-symbolizer: Move out of CLANG_EXTRAS, into CLANG
ASAN reports become a lot more useful with llvm-symbolizer in $PATH, and the
build is not much more time-consuming. Th
MFC r348504 (by kevans):
llvm-symbolizer: Move out of CLANG_EXTRAS, into CLANG
ASAN reports become a lot more useful with llvm-symbolizer in $PATH, and the
build is not much more time-consuming. The added benefit is that the
resulting reports will actually include symbol information; without, thread
trace information includes a bunch of addresses that immediately resolve to
an inline function in
^/contrib/compiler-rt/lib/sanitizer_common/sanitizer_common.h and take a
little more effort to examine.
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D20484
MFC r349004:
Upgrade our copies of clang, llvm, lld, lldb, compiler-rt, libc++,
libunwind and openmp to the upstream release_80 branch r363030
(effectively, 8.0.1 rc2). The 8.0.1 release should follow this within a
week or so.
MFC r349351 (by jhibbits, partially):
powerpc: Transition to Secure-PLT, like most other OSs (Toolchain part)
Summary:
Toolchain follow-up to r349350. LLVM patches will be submitted upstream for
9.0 as well.
The bsd.cpu.mk change is required because GNU ld assumes BSS-PLT if it
cannot determine for certain that it needs Secure-PLT, and some binaries do
not compile in such a way to make it know to use Secure-PLT.
Reviewed By: nwhitehorn, bdragon, pfg
Differential Revision: https://reviews.freebsd.org/D20598
MFC r349793:
Upgrade our copies of clang, llvm, lld, lldb, compiler-rt, libc++,
libunwind and openmp to the upstream release_80 branch r364487
(effectively, 8.0.1 rc3). The 8.0.1 release will most likely
have no further changes.
MFC r350177:
Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
8.0.1 final release r366581. The only functional change is a fix for a
mismerge of upstream r360816, which properly restores the r2 register
when unwinding on PowerPC64 (See https://reviews.freebsd.org/D20337).
Relnotes: yes
PR: 236062
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| 72ccea31 | 12-Jul-2019 |
Dimitry Andric <[email protected]> |
MFC r349583:
Pull in r360968 from upstream llvm trunk (by Philip Reames):
Clarify comments on helpers used by LFTR [NFC]
I'm slowly wrapping my head around this code, and am making comment
i
MFC r349583:
Pull in r360968 from upstream llvm trunk (by Philip Reames):
Clarify comments on helpers used by LFTR [NFC]
I'm slowly wrapping my head around this code, and am making comment
improvements where I can.
Pull in r360972 from upstream llvm trunk (by Philip Reames):
[LFTR] Factor out a helper function for readability purpose [NFC]
Pull in r360976 from upstream llvm trunk (by Philip Reames):
[IndVars] Don't reimplement Loop::isLoopInvariant [NFC]
Using dominance vs a set membership check is indistinguishable from a
compile time perspective, and the two queries return equivelent
results. Simplify code by using the existing function.
Pull in r360978 from upstream llvm trunk (by Philip Reames):
[LFTR] Strengthen assertions in genLoopLimit [NFCI]
Pull in r362292 from upstream llvm trunk (by Nikita Popov):
[IndVarSimplify] Fixup nowrap flags during LFTR (PR31181)
Fix for https://bugs.llvm.org/show_bug.cgi?id=31181 and partial fix
for LFTR poison handling issues in general.
When LFTR moves a condition from pre-inc to post-inc, it may now
depend on value that is poison due to nowrap flags. To avoid this, we
clear any nowrap flag that SCEV cannot prove for the post-inc addrec.
Additionally, LFTR may switch to a different IV that is dynamically
dead and as such may be arbitrarily poison. This patch will correct
nowrap flags in some but not all cases where this happens. This is
related to the adoption of IR nowrap flags for the pre-inc addrec.
(See some of the switch_to_different_iv tests, where flags are not
dropped or insufficiently dropped.)
Finally, there are likely similar issues with the handling of GEP
inbounds, but we don't have a test case for this yet.
Differential Revision: https://reviews.llvm.org/D60935
Pull in r362971 from upstream llvm trunk (by Philip Reames):
Prepare for multi-exit LFTR [NFC]
This change does the plumbing to wire an ExitingBB parameter through
the LFTR implementation, and reorganizes the code to work in terms of
a set of individual loop exits. Most of it is fairly obvious, but
there's one key complexity which makes it worthy of consideration.
The actual multi-exit LFTR patch is in D62625 for context.
Specifically, it turns out the existing code uses the backedge taken
count from before a IV is widened. Oddly, we can end up with a
different (more expensive, but semantically equivelent) BE count for
the loop when requerying after widening. For the nestedIV example
from elim-extend, we end up with the following BE counts:
BEFORE: (-2 + (-1 * %innercount) + %limit)
AFTER: (-1 + (sext i32 (-1 + %limit) to i64) + (-1 * (sext i32 %innercount to i64))<nsw>)
This is the only test in tree which seems sensitive to this
difference. The actual result of using the wider BETC on this example
is that we actually produce slightly better code. :)
In review, we decided to accept that test change. This patch is
structured to preserve the old behavior, but a separate change will
immediate follow with the behavior change. (I wanted it separate for
problem attribution purposes.)
Differential Revision: https://reviews.llvm.org/D62880
Pull in r362975 from upstream llvm trunk (by Philip Reames):
[LFTR] Use recomputed BE count
This was discussed as part of D62880. The basic thought is that
computing BE taken count after widening should produce (on average)
an equally good backedge taken count as the one before widening.
Since there's only one test in the suite which is impacted by this
change, and it's essentially equivelent codegen, that seems to be a
reasonable assertion. This change was separated from r362971 so that
if this turns out to be problematic, the triggering piece is obvious
and easily revertable.
For the nestedIV example from elim-extend.ll, we end up with the
following BE counts:
BEFORE: (-2 + (-1 * %innercount) + %limit)
AFTER: (-1 + (sext i32 (-1 + %limit) to i64) + (-1 * (sext i32 %innercount to i64))<nsw>)
Note that before is an i32 type, and the after is an i64. Truncating
the i64 produces the i32.
Pull in r362980 from upstream llvm trunk (by Philip Reames):
Factor out a helper function for readability and reuse in a future
patch [NFC]
Pull in r363613 from upstream llvm trunk (by Philip Reames):
Fix a bug w/inbounds invalidation in LFTR (recommit)
Recommit r363289 with a bug fix for crash identified in pr42279.
Issue was that a loop exit test does not have to be an icmp, leading
to a null dereference crash when new logic was exercised for that
case. Test case previously committed in r363601.
Original commit comment follows:
This contains fixes for two cases where we might invalidate inbounds
and leave it stale in the IR (a miscompile). Case 1 is when switching
to an IV with no dynamically live uses, and case 2 is when doing
pre-to-post conversion on the same pointer type IV.
The basic scheme used is to prove that using the given IV (pre or
post increment forms) would have to already trigger UB on the path to
the test we're modifying. As such, our potential UB triggering use
does not change the semantics of the original program.
As was pointed out in the review thread by Nikita, this is defending
against a separate issue from the hasConcreteDef case. This is about
poison, that's about undef. Unfortunately, the two are different, see
Nikita's comment for a fuller explanation, he explains it well.
(Note: I'm going to address Nikita's last style comment in a separate
commit just to minimize chance of subtle bugs being introduced due to
typos.)
Differential Revision: https://reviews.llvm.org/D62939
Pull in r363875 from upstream llvm trunk (by Philip Reames):
[LFTR] Rename variable to minimize confusion [NFC]
(Recommit of r363293 which was reverted when a dependent patch was.)
As pointed out by Nikita in D62625, BackedgeTakenCount is generally
used to refer to the backedge taken count of the loop. A conditional
backedge taken count - one which only applies if a particular exit is
taken - is called a ExitCount in SCEV code, so be consistent here.
Pull in r363877 from upstream llvm trunk (by Philip Reames):
[LFTR] Stylistic cleanup as suggested in last review comment of
D62939 [NFC]
(Resumbit of r363292 which was reverted along w/an earlier patch)
Pull in r364346 from upstream llvm trunk (by Philip Reames):
[LFTR] Adjust debug output to include extensions (if any)
Pull in r364693 from upstream llvm trunk (by Philip Reames):
[IndVars] Remove a bit of manual constant folding [NFC]
SCEV is more than capable of folding (add x, trunc(0)) to x.
Pull in r364709 from upstream llvm trunk (by Nikita Popov):
[LFTR] Fix post-inc pointer IV with truncated exit count (PR41998)
Fixes https://bugs.llvm.org/show_bug.cgi?id=41998. Usually when we
have a truncated exit count we'll truncate the IV when comparing
against the limit, in which case exit count overflow in post-inc form
doesn't matter. However, for pointer IVs we don't do that, so we have
to be careful about incrementing the IV in the wide type.
I'm fixing this by removing the IVCount variable (which was ExitCount
or ExitCount+1) and replacing it with a UsePostInc flag, and then
moving the actual limit adjustment to the individual cases (which
are: pointer IV where we add to the wide type, integer IV where we
add to the narrow type, and constant integer IV where we add to the
wide type).
Differential Revision: https://reviews.llvm.org/D63686
Together, these should fix a hang when building the textproc/htmldoc
port, due to an incorrect loop optimization.
PR: 237515
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| c46dc820 | 16-Feb-2019 |
Dimitry Andric <[email protected]> |
MFC r344112:
Pull in r353907 from upstream llvm trunk (by Reid Kleckner):
[MC] Make symbol version errors non-fatal
We stil don't have a source location, which is pretty lame, but at
least w
MFC r344112:
Pull in r353907 from upstream llvm trunk (by Reid Kleckner):
[MC] Make symbol version errors non-fatal
We stil don't have a source location, which is pretty lame, but at
least we won't tell the user to file a clang bug report anymore.
Fixes PR40712
This will make errors for symbols with @@ versions that are not defined
non-fatal. For example:
void f(void)
{
__asm__(".symver foo,bar@@baz");
}
will now result in:
error: versioned symbol bar@@baz must be defined
instead of clang crashing with a diagnostic report.
PR: 234671
Upstream PR: https://bugs.llvm.org/show_bug.cgi?id=40712
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| 0556cfad | 20-Apr-2018 |
Dimitry Andric <[email protected]> |
Recommit r332501, with an additional upstream fix for "Cannot lower
EFLAGS copy that lives out of a basic block!" errors on i386.
Pull in r325446 from upstream clang trunk (by me):
[X86] Add 'sah
Recommit r332501, with an additional upstream fix for "Cannot lower
EFLAGS copy that lives out of a basic block!" errors on i386.
Pull in r325446 from upstream clang trunk (by me):
[X86] Add 'sahf' CPU feature to frontend
Summary:
Make clang accept `-msahf` (and `-mno-sahf`) flags to activate the
`+sahf` feature for the backend, for bug 36028 (Incorrect use of
pushf/popf enables/disables interrupts on amd64 kernels). This was
originally submitted in bug 36037 by Jonathan Looney
<[email protected]>.
As described there, GCC also uses `-msahf` for this feature, and the
backend already recognizes the `+sahf` feature. All that is needed is
to teach clang to pass this on to the backend.
The mapping of feature support onto CPUs may not be complete; rather,
it was chosen to match LLVM's idea of which CPUs support this feature
(see lib/Target/X86/X86.td).
I also updated the affected test case (CodeGen/attr-target-x86.c) to
match the emitted output.
Reviewers: craig.topper, coby, efriedma, rsmith
Reviewed By: craig.topper
Subscribers: emaste, cfe-commits
Differential Revision: https://reviews.llvm.org/D43394
Pull in r328944 from upstream llvm trunk (by Chandler Carruth):
[x86] Expose more of the condition conversion routines in the public
API for X86's instruction information. I've now got a second patch
under review that needs these same APIs. This bit is nicely
orthogonal and obvious, so landing it. NFC.
Pull in r329414 from upstream llvm trunk (by Craig Topper):
[X86] Merge itineraries for CLC, CMC, and STC.
These are very simple flag setting instructions that appear to only
be a single uop. They're unlikely to need this separation.
Pull in r329657 from upstream llvm trunk (by Chandler Carruth):
[x86] Introduce a pass to begin more systematically fixing PR36028
and similar issues.
The key idea is to lower COPY nodes populating EFLAGS by scanning the
uses of EFLAGS and introducing dedicated code to preserve the
necessary state in a GPR. In the vast majority of cases, these uses
are cmovCC and jCC instructions. For such cases, we can very easily
save and restore the necessary information by simply inserting a
setCC into a GPR where the original flags are live, and then testing
that GPR directly to feed the cmov or conditional branch.
However, things are a bit more tricky if arithmetic is using the
flags. This patch handles the vast majority of cases that seem to
come up in practice: adc, adcx, adox, rcl, and rcr; all without
taking advantage of partially preserved EFLAGS as LLVM doesn't
currently model that at all.
There are a large number of operations that techinaclly observe
EFLAGS currently but shouldn't in this case -- they typically are
using DF. Currently, they will not be handled by this approach.
However, I have never seen this issue come up in practice. It is
already pretty rare to have these patterns come up in practical code
with LLVM. I had to resort to writing MIR tests to cover most of the
logic in this pass already. I suspect even with its current amount
of coverage of arithmetic users of EFLAGS it will be a significant
improvement over the current use of pushf/popf. It will also produce
substantially faster code in most of the common patterns.
This patch also removes all of the old lowering for EFLAGS copies,
and the hack that forced us to use a frame pointer when EFLAGS copies
were found anywhere in a function so that the dynamic stack
adjustment wasn't a problem. None of this is needed as we now lower
all of these copies directly in MI and without require stack
adjustments.
Lots of thanks to Reid who came up with several aspects of this
approach, and Craig who helped me work out a couple of things
tripping me up while working on this.
Differential Revision: https://reviews.llvm.org/D45146
Pull in r329673 from upstream llvm trunk (by Chandler Carruth):
[x86] Model the direction flag (DF) separately from the rest of
EFLAGS.
This cleans up a number of operations that only claimed te use EFLAGS
due to using DF. But no instructions which we think of us setting
EFLAGS actually modify DF (other than things like popf) and so this
needlessly creates uses of EFLAGS that aren't really there.
In fact, DF is so restrictive it is pretty easy to model. Only STD,
CLD, and the whole-flags writes (WRFLAGS and POPF) need to model
this.
I've also somewhat cleaned up some of the flag management instruction
definitions to be in the correct .td file.
Adding this extra register also uncovered a failure to use the
correct datatype to hold X86 registers, and I've corrected that as
necessary here.
Differential Revision: https://reviews.llvm.org/D45154
Pull in r330264 from upstream llvm trunk (by Chandler Carruth):
[x86] Fix PR37100 by teaching the EFLAGS copy lowering to rewrite
uses across basic blocks in the limited cases where it is very
straight forward to do so.
This will also be useful for other places where we do some limited
EFLAGS propagation across CFG edges and need to handle copy rewrites
afterward. I think this is rapidly approaching the maximum we can and
should be doing here. Everything else begins to require either heroic
analysis to prove how to do PHI insertion manually, or somehow
managing arbitrary PHI-ing of EFLAGS with general PHI insertion.
Neither of these seem at all promising so if those cases come up,
we'll almost certainly need to rewrite the parts of LLVM that produce
those patterns.
We do now require dominator trees in order to reliably diagnose
patterns that would require PHI nodes. This is a bit unfortunate but
it seems better than the completely mysterious crash we would get
otherwise.
Differential Revision: https://reviews.llvm.org/D45673
Together, these should ensure clang does not use pushf/popf sequences to
save and restore flags, avoiding problems with unrelated flags (such as
the interrupt flag) being restored unexpectedly.
Requested by: jtl
PR: 225330
MFC after: 1 week
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