This is the third patch in a small series. It contains the CodeGen support for lowering the gc.statepoint intrinsic sequences (223078) to the STATEPOINT pseudo machine instruction (223085). The change also includes the set of helper routines and classes for working with gc.statepoints, gc.relocates, and gc.results since the lowering code uses them.
With this change, gc.statepoints should be functionally complete. The documentation will follow in the fourth change, and there will likely be some cleanup changes, but interested parties can start experimenting now.
I'm not particularly happy with the amount of code or complexity involved with the lowering step, but at least it's fairly well isolated. The statepoint lowering code is split into it's own files and anyone not working on the statepoint support itself should be able to ignore it.
During the lowering process, we currently spill aggressively to stack. This is not entirely ideal (and we have plans to do better), but it's functional, relatively straight forward, and matches closely the implementations of the patchpoint intrinsics. Most of the complexity comes from trying to keep relocated copies of values in the same stack slots across statepoints. Doing so avoids the insertion of pointless load and store instructions to reshuffle the stack. The current implementation isn't as effective as I'd like, but it is functional and 'good enough' for many common use cases.
In the long term, I'd like to figure out how to integrate the statepoint lowering with the register allocator. In principal, we shouldn't need to eagerly spill at all. The register allocator should do any spilling required and the statepoint should simply record that fact. Depending on how challenging that turns out to be, we may invest in a smarter global stack slot assignment mechanism as a stop gap measure.
Reviewed by: atrick, ributzka
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223137 91177308-0d34-0410-b5e6-96231b3b80d8
Follow up from r222926. Also handle multiple destinations from merged
cases on multiple and subsequent phi instructions.
rdar://problem/19106978
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223135 91177308-0d34-0410-b5e6-96231b3b80d8
Go through implicit defs of CSMI and MI, and clear the kill flags on
their uses in all the instructions between CSMI and MI.
We might have made some of the kill flags redundant, consider:
subs ... %NZCV<imp-def> <- CSMI
csinc ... %NZCV<imp-use,kill> <- this kill flag isn't valid anymore
subs ... %NZCV<imp-def> <- MI, to be eliminated
csinc ... %NZCV<imp-use,kill>
Since we eliminated MI, and reused a register imp-def'd by CSMI
(here %NZCV), that register, if it was killed before MI, should have
that kill flag removed, because it's lifetime was extended.
Also, add an exhaustive testcase for the motivating example.
Reviewed by: Juergen Ributzka <juergen@apple.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223133 91177308-0d34-0410-b5e6-96231b3b80d8
The blocking code originated in ARM, which is more aggressive about casting
types to a canonical representative before doing anything else, so I missed out
most vector HFAs and broke the ABI. This should fix it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223126 91177308-0d34-0410-b5e6-96231b3b80d8
This operating system type represents the AMD HSA runtime,
and will be required by the R600 backend in order to generate
correct code for this runtime.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223124 91177308-0d34-0410-b5e6-96231b3b80d8
Load instructions are inserted into loop preheaders when sinking stores
and later removed if not used by the SSA updater. Avoid sinking if the
loop has no preheader and avoid crashes. This fixes one more side effect
of not handling indirectbr instructions properly on LoopSimplify.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223119 91177308-0d34-0410-b5e6-96231b3b80d8
Removing an unused function which is causing one of the build bots to fail.
This was introduced in the commit r223113. A proper cleanup of the so_imm
tblgen defintion (made redundant by the mod_imm definition) needs to happen
soon.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223115 91177308-0d34-0410-b5e6-96231b3b80d8
Certain ARM instructions accept 32-bit immediate operands encoded as a 8-bit
integer value (0-255) and a 4-bit rotation (0-30, even). Current ARM assembly
syntax support in LLVM allows the decoded (32-bit) immediate to be specified
as a single immediate operand for such instructions:
mov r0, #4278190080
The ARMARM defines an extended assembly syntax allowing the encoding to be made
more explicit, as in:
mov r0, #255, #8 ; (same 32-bit value as above)
The behaviour of the two instructions can be different w.r.t flags, which is
documented under "Modified immediate constants" in ARMARM. This patch enables
support for this extended syntax at the MC layer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223113 91177308-0d34-0410-b5e6-96231b3b80d8
The default ARM floating-point mode does not support IEEE 754 mode exactly. Of
relevance to this patch is that input denormals are flushed to zero. The way in
which they're flushed to zero depends on the architecture,
* For VFPv2, it is implementation defined as to whether the sign of zero is
preserved.
* For VFPv3 and above, the sign of zero is always preserved when a denormal
is flushed to zero.
When FP support has been disabled, the strategy taken by this patch is to
assume the software support will mirror the behaviour of the hardware support
for the target *if it existed*. That is, for architectures which can only have
VFPv2, it is assumed the software will flush to positive zero. For later
architectures it is assumed the software will flush to zero preserving sign.
Change-Id: Icc5928633ba222a4ba3ca8c0df44a440445865fd
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223110 91177308-0d34-0410-b5e6-96231b3b80d8
In both the Unix and Windows variants, std::getenv was called and the
result passed directly to a function accepting a StringRef. This isn't
OK because it might return a null pointer and that causes the StringRef
constructor to assert (and generally produces crash-prone code if
asserts are disabled). Fix this by independently testing the result as
non-null prior to splitting things.
This in turn uncovered another bug in the Unix variant where it would
infinitely recurse if PATH="", or after this fix if PATH isn't set.
There is no need to recurse at all. Slightly re-arrange the code to make
it clear that we can just fixup the Paths argument based on the
environment if we find anything.
I don't know of a particularly useful way to test these routines in
LLVM. I'll commit a test to Clang that ensures that its driver correctly
handles various settings of PATH. However, I have no idea how to
correctly write a Windows test for the PATHEXT change. Any Windows
developers who could provide such a test, please have at. =D
Many thanks to Nick Lewycky and others for helping debug this. =/ It was
quite nasty for us to track down.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223099 91177308-0d34-0410-b5e6-96231b3b80d8
System memory allocation functions, which are identified at the IR level by the
noalias attribute on the return value, must return a pointer into a memory region
disjoint from any other memory accessible to the caller. We can use this
property to simplify pointer comparisons between allocated memory and local
stack addresses and the addresses of global variables. Neither the stack nor
global variables can overlap with the region used by the memory allocator.
Fixes PR21556.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223093 91177308-0d34-0410-b5e6-96231b3b80d8
This is the second patch in a small series. This patch contains the MachineInstruction and x86-64 backend pieces required to lower Statepoints. It does not include the code to actually generate the STATEPOINT machine instruction and as a result, the entire patch is currently dead code. I will be submitting the SelectionDAG parts within the next 24-48 hours. Since those pieces are by far the most complicated, I wanted to minimize the size of that patch. That patch will include the tests which exercise the functionality in this patch. The entire series can be seen as one combined whole in http://reviews.llvm.org/D5683.
The STATEPOINT psuedo node is generated after all gc values are explicitly spilled to stack slots. The purpose of this node is to wrap an actual call instruction while recording the spill locations of the meta arguments used for garbage collection and other purposes. The STATEPOINT is modeled as modifing all of those locations to prevent backend optimizations from forwarding the value from before the STATEPOINT to after the STATEPOINT. (Doing so would break relocation semantics for collectors which wish to relocate roots.)
The implementation of STATEPOINT is closely modeled on PATCHPOINT. Eventually, much of the code in this patch will be removed. The long term plan is to merge the functionality provided by statepoints and patchpoints. Merging their implementations in the backend is likely to be a good starting point.
Reviewed by: atrick, ributzka
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223085 91177308-0d34-0410-b5e6-96231b3b80d8
The statepoint intrinsics are intended to enable precise root tracking through the compiler as to support garbage collectors of all types. The addition of the statepoint intrinsics to LLVM should have no impact on the compilation of any program which does not contain them. There are no side tables created, no extra metadata, and no inhibited optimizations.
A statepoint works by transforming a call site (or safepoint poll site) into an explicit relocation operation. It is the frontend's responsibility (or eventually the safepoint insertion pass we've developed, but that's not part of this patch series) to ensure that any live pointer to a GC object is correctly added to the statepoint and explicitly relocated. The relocated value is just a normal SSA value (as seen by the optimizer), so merges of relocated and unrelocated values are just normal phis. The explicit relocation operation, the fact the statepoint is assumed to clobber all memory, and the optimizers standard semantics ensure that the relocations flow through IR optimizations correctly.
This is the first patch in a small series. This patch contains only the IR parts; the documentation and backend support will be following separately. The entire series can be seen as one combined whole in http://reviews.llvm.org/D5683.
Reviewed by: atrick, ributzka
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223078 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
".weak" symbols cannot be consumed by ptxas (PR21685). This patch makes the
weak directive in MCAsmPrinter customizable, and disables emitting ".weak"
symbols for NVPTX.
Test Plan: weak-linkage.ll
Reviewers: jholewinski
Reviewed By: jholewinski
Subscribers: majnemer, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D6455
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223077 91177308-0d34-0410-b5e6-96231b3b80d8
r208210 introduced an optimization that improves the vector select
codegen by doing the setcc on vectors directly.
This is a problem they the setcc operands are i1s, because the
optimization would create vectors of i1, which aren't legal.
Part of PR21549.
Differential Revision: http://reviews.llvm.org/D6308
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223075 91177308-0d34-0410-b5e6-96231b3b80d8
r213378 improved f16 bitcasts, so that they go directly through subregs,
instead of through the stack. That code now causes an assertion failure
for bitcasts from other 16-bits types (most importantly v2i8).
Correct that by doing the custom lowering for i16 bitcasts only when the
input is an f16.
Part of PR21549.
Differential Revision: http://reviews.llvm.org/D6307
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223074 91177308-0d34-0410-b5e6-96231b3b80d8
The MachineVerifier used to check that there was always exactly one
unconditional branch to a non-landingpad (normal) successor.
If that normal successor to an invoke BB is unreachable, it seems
reasonable to only have one successor, the landing pad.
On targets other than AArch64 (and on AArch64 with a different testcase),
the branch folder turns the branch to the landing pad into a fallthrough.
The MachineVerifier, which relies on AnalyzeBranch, is unable to check
the condition, and doesn't complain. However, it does in this specific
testcase, where the branch to the landing pad remained.
Make the MachineVerifier accept it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223059 91177308-0d34-0410-b5e6-96231b3b80d8
At the only point in the code it is used, we haven't added any of the src types
to DstStructTypesSet yet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223057 91177308-0d34-0410-b5e6-96231b3b80d8
An unreachable default destination can be exploited by other optimizations, and
SDag lowering is now prepared to handle them efficiently.
For example, branches to the unreachable destination will be optimized away,
such as in the case of range checks for switch lookup tables.
On 64-bit Linux, this reduces the size of a clang bootstrap by 80 kB (and
Chromium by 30 kB).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223050 91177308-0d34-0410-b5e6-96231b3b80d8
This can significantly reduce the size of the switch, allowing for more
efficient lowering.
I also worked with the idea of exploiting unreachable defaults by
omitting the range check for jump tables, but always ended up with a
non-neglible binary size increase. It might be worth looking into some more.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223049 91177308-0d34-0410-b5e6-96231b3b80d8
The explicit set of destination types is not fully redundant when lazy loading
since the TypeFinder will not find types used only in function bodies.
This keeps the logic to drop the name of mapped types since it still helps
with avoiding further renaming.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223043 91177308-0d34-0410-b5e6-96231b3b80d8
- Fix missing SALU format bits
- Remove unused isSALUInstr
- Add isVALU
- Switch isDS to use a bit like the others
- Move SIInstrInfo::is* functions to header
- Reorder so they are approximately sorted by type (SALU, VALU, memory)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223038 91177308-0d34-0410-b5e6-96231b3b80d8
This change makes MemorySanitizer instrumentation a bit more strict
about instructions that have no origin id assigned to them.
This would have caught the bug that was fixed in r222918.
No functional change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222997 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
PowerPC DWARF unwind info defined CFA as SP + offset even in a function
where the stack had been dynamically realigned. This clearly doesn't
work because the offset from SP to CFA is not a constant. Fix it by
defining CFA as BP instead.
This was causing the AddressSanitizer null_deref test to fail 50% of
the time, depending on whether SP happened to be 32-byte aligned on
entry to a particular function or not.
Reviewers: willschm, uweigand, hfinkel
Reviewed By: hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D6410
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222996 91177308-0d34-0410-b5e6-96231b3b80d8
Add checkDecodedInstruction for post-decode checking of instructions, to catch
the corner cases like HVC that don't fit into the general pattern. Needed to
check for an invalid condition field in instruction encoding despite HVC not
taking a predicate.
Patch by Matthew Wahab.
Change-Id: I48e28de981d7a9e43569594da3c45fb478b4f795
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222992 91177308-0d34-0410-b5e6-96231b3b80d8
