Commit Graph

216 Commits

Author SHA1 Message Date
Philip Reames 3da1a9634e [Statepoints] Support lowering gc relocations to virtual registers
(Disabled under flag for the moment)

This is part of a larger project wherein we are finally integrating lowering of gc live operands with the register allocator.  Today, we force spill all operands in SelectionDAG.  The code to do so is distinctly non-optimal.  The approach this patch is working towards is to instead lower the relocations directly into the MI form, and let the register allocator pick which ones get spilled and which stack slots they get spilled to.  In terms of performance, the later part is actually more important as it avoids redundant shuffling of values between stack slots.

This particular change adds ISEL support to produce the variadic def STATEPOINT form required by the above.  In particular, the first N are lowered to variadic tied def/use pairs.  So new statepoint looks like this:
reloc1,reloc2,... = STATEPOINT ..., base1, derived1<tied-def0>, base2, derived2<tied-def1>, ...

N is limited by the maximal number of tied registers machine instruction can have (15 at the moment).

The current patch is restricted to handling relocations within a single basic block.  Cross block relocations (e.g. invokes) are handled via the legacy mechanism.  This restriction will be relaxed in future patches.

Patch By: dantrushin
Differential Revision: https://reviews.llvm.org/D81648
2020-07-25 14:26:05 -07:00
Simon Pilgrim fe0006c882 TargetLowering.h - remove unnecessary TargetMachine.h include. NFC
Replace with forward declaration and move dependency down to source files that actually need it.

Both TargetLowering.h and TargetMachine.h are 2 of the most expensive headers (top 10) in the ClangBuildAnalyzer report when building llc.
2020-05-23 19:49:38 +01:00
Craig Topper 8c72b0271b [CodeGen] Use Align in MachineConstantPool. 2020-05-12 10:06:40 -07:00
Craig Topper bebdc62c3f [SelectionDAG] Remove ConstantPoolSDNode::getAlignment.
Use getAlign instead.

Differential Revision: https://reviews.llvm.org/D79459
2020-05-08 16:04:11 -07:00
Simon Pilgrim 032738d17e InstrEmitter.h - reduce SelectionDAG.h include to SelectionDAGNodes.h include.
Add SDDbgLabel/TargetLowering forward declarations.
Add the full SelectionDAG.h include to InstrEmitter.cpp.
2020-04-19 11:52:31 +01:00
Matt Arsenault 586769cce2 DAG: Use Register 2020-04-08 13:44:31 -04:00
Matt Arsenault 30ebafaa56 CodeGen: Convert some TII hooks to use Register 2020-04-03 14:52:54 -04:00
Thomas Lively 7b64a59060 Reland "[WebAssembly][InstrEmitter] Foundation for multivalue call lowering"
This reverts commit 649aba93a2, now that
the approach started there has been shown to be workable in the patch
series culminating in https://reviews.llvm.org/D74192.
2020-02-18 13:49:46 -08:00
Jeremy Morse 6531a78ac4 Revert "[DebugInfo] Remove some users of DBG_VALUEs IsIndirect field"
This reverts commit ed29dbaafa.

I'm backing out D68945, which as the discussion for D73526 shows, doesn't
seem to handle the -O0 path through the codegen backend correctly. I'll
reland the patch when a fix is worked out, apologies for all the churn.
The two parent commits are part of this revert too.

Conflicts:
	llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
	llvm/test/DebugInfo/X86/dbg-addr-dse.ll

SelectionDAGBuilder conflict is due to a nearby change in e39e2b4a79
that's technically unrelated. dbg-addr-dse.ll conflicted because
41206b61e3 (legitimately) changes the order of two lines.

There are further modifications to dbg-value-func-arg.ll: it landed after
the patch being reverted, and I've converted indirection to be represented
by the isIndirect field rather than DW_OP_deref.
2020-02-06 14:41:40 +00:00
Jeremy Morse ed5998d21e Revert "[SafeStack][DebugInfo] Insert DW_OP_deref in correct location"
This reverts commit 2d3174c4df.

The overall solution for this problem is reverting D68945, which wasn't
handling the -O0 path through the codegen backend correctly. See:
discussion in D73526.
2020-02-06 14:41:39 +00:00
Thomas Lively 649aba93a2 Revert "[WebAssembly][InstrEmitter] Foundation for multivalue call lowering"
Summary:
This reverts commit 3ef169e586. The
purpose of this commit was to allow stack machines to perform
instruction selection for instructions with variadic defs. However,
MachineInstrs fundamentally cannot support variadic defs right now, so
this change does not turn out to be useful.

Depends on D73927.

Reviewers: aheejin

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73928
2020-02-04 20:04:59 -08:00
Leonard Chan 2d3174c4df [SafeStack][DebugInfo] Insert DW_OP_deref in correct location
This patch addresses the issue found in https://bugs.llvm.org/show_bug.cgi?id=44585
where a DW_OP_deref was placed at the end of a dwarf expression, resulting in corrupt
symbols when debugging.

This is an attempt to reland with a few fixes for buildbot since I
haven't merged from master in a bit.

Differential Revision: https://reviews.llvm.org/D73526
2020-01-30 17:09:42 -08:00
Leonard Chan 3b23453b6c Revert "[SafeStack][DebugInfo] Insert DW_OP_deref in correct location"
This reverts commit fff6a1b0f1.

This was breaking a bunch of buildbots.
2020-01-30 16:18:41 -08:00
Leonard Chan fff6a1b0f1 [SafeStack][DebugInfo] Insert DW_OP_deref in correct location
This patch addresses the issue found in https://bugs.llvm.org/show_bug.cgi?id=44585
where a DW_OP_deref was placed at the end of a dwarf expression, resulting in
corrupt symbols when debugging.

Differential Revision: https://reviews.llvm.org/D73526
2020-01-30 15:58:37 -08:00
Thomas Lively 3ef169e586 [WebAssembly][InstrEmitter] Foundation for multivalue call lowering
Summary:
WebAssembly is unique among upstream targets in that it does not at
any point use physical registers to store values. Instead, it uses
virtual registers to model positions in its value stack. This means
that some target-independent lowering activities that would use
physical registers need to use virtual registers instead for
WebAssembly and similar downstream targets. This CL generalizes the
existing `usesPhysRegsForPEI` lowering hook to
`usesPhysRegsForValues` in preparation for using it in more places.

One such place is in InstrEmitter for instructions that have variadic
defs. On register machines, it only makes sense for these defs to be
physical registers, but for WebAssembly they must be virtual registers
like any other values. This CL changes InstrEmitter to check the new
target lowering hook to determine whether variadic defs should be
physical or virtual registers.

These changes are necessary to support a generalized CALL instruction
for WebAssembly that is capable of returning an arbitrary number of
arguments. Fully implementing that instruction will require additional
changes that are described in comments here but left for a follow up
commit.

Reviewers: aheejin, dschuff, qcolombet

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71484
2020-01-21 11:13:46 -08:00
Ulrich Weigand f0fd11df7d [FPEnv] Invert sense of MIFlag::FPExcept flag
In D71841 we inverted the sense of the SDNode-level flag to ensure all nodes
default to potentially raising FP exceptions unless otherwise specified --
i.e. if we forget to propagate the flag somewhere, the effect is now only
lost performance, not incorrect code.

However, the related flag at the MI level still defaults to nodes not raising
FP exceptions unless otherwise specified. To be fully on the (conservatively)
safe side, we should invert that flag as well.

This patch does so by replacing MIFlag::FPExcept with MIFlag::NoFPExcept.
(Note that this does also introduce an incompatible change in the MIR format.)

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D72466
2020-01-10 15:34:50 +01:00
Ulrich Weigand 63336795f0 [FPEnv] Default NoFPExcept SDNodeFlag to false
The NoFPExcept bit in SDNodeFlags currently defaults to true, unlike all
other such flags. This is a problem, because it implies that all code that
transforms SDNodes without copying flags can introduce a correctness bug,
not just a missed optimization.

This patch changes the default to false. This makes it necessary to move
setting the (No)FPExcept flag for constrained intrinsics from the
visitConstrainedIntrinsic routine to the generic visit routine at the
place where the other flags are set, or else the intersectFlagsWith
call would erase the NoFPExcept flag again.

In order to avoid making non-strict FP code worse, whenever
SelectionDAGISel::SelectCodeCommon matches on a set of orignal nodes
none of which can raise FP exceptions, it will preserve this property
on all results nodes generated, by setting the NoFPExcept flag on
those result nodes that would otherwise be considered as raising
an FP exception.

To check whether or not an SD node should be considered as raising
an FP exception, the following logic applies:

- For machine nodes, check the mayRaiseFPException property of
  the underlying MI instruction
- For regular nodes, check isStrictFPOpcode
- For target nodes, check a newly introduced isTargetStrictFPOpcode

The latter is implemented by reserving a range of target opcodes,
similarly to how memory opcodes are identified. (Note that there a
bit of a quirk in identifying target nodes that are both memory nodes
and strict FP nodes. To simplify the logic, right now all target memory
nodes are automatically also considered strict FP nodes -- this could
be fixed by adding one more range.)

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D71841
2020-01-02 16:59:45 +01:00
Jeremy Morse ed29dbaafa [DebugInfo] Remove some users of DBG_VALUEs IsIndirect field
This patch kills off a significant user of the "IsIndirect" field of
DBG_VALUE machine insts. Brought up in in PR41675, IsIndirect is
techncally redundant as it can be expressed by the DIExpression of a
DBG_VALUE inst, and it isn't helpful to have two ways of expressing
things.

Rather than setting IsIndirect, have DBG_VALUE creators add an extra deref
to the insts DIExpression. There should now be no appearences of
IsIndirect=True from isel down to LiveDebugVariables / VirtRegRewriter,
which is ensured by an assertion in LDVImpl::handleDebugValue. This means
we also get to delete the IsIndirect handling in LiveDebugVariables. Tests
can be upgraded by for example swapping the following IsIndirect=True
DBG_VALUE:

  DBG_VALUE $somereg, 0, !123, !DIExpression(DW_OP_foo)

With one where the indirection is in the DIExpression, by _appending_
a deref:

  DBG_VALUE $somereg, $noreg, !123, !DIExpression(DW_OP_foo, DW_OP_deref)

Which both mean the same thing. 

Most of the test changes in this patch are updates of that form; also some
changes in how the textual assembly printer handles these insts.

Differential Revision: https://reviews.llvm.org/D68945

llvm-svn: 374877
2019-10-15 10:46:24 +00:00
Craig Topper 4d1df2aa23 [TargetRegisterInfo] Remove SVT argument from getCommonSubClass.
This was added to support fp128 on x86-64, but appears to be
unneeded now. This may be because the FR128 register class
added back then was merged with the VR128 register class later.

llvm-svn: 371815
2019-09-13 05:24:37 +00:00
Daniel Sanders 0c47611131 Apply llvm-prefer-register-over-unsigned from clang-tidy to LLVM
Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).

Partial reverts in:
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned&
MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register
PPCFastISel.cpp - No Register::operator-=()
PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned&
MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor

Manual fixups in:
ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned&
HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register
HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register.
PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned&

Depends on D65919

Reviewers: arsenm, bogner, craig.topper, RKSimon

Reviewed By: arsenm

Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65962

llvm-svn: 369041
2019-08-15 19:22:08 +00:00
Matt Arsenault f4d3113a5f CodeGen: Migration to using Register
llvm-svn: 367974
2019-08-06 03:59:31 +00:00
Daniel Sanders 2bea69bf65 Finish moving TargetRegisterInfo::isVirtualRegister() and friends to llvm::Register as started by r367614. NFC
llvm-svn: 367633
2019-08-01 23:27:28 +00:00
Ulrich Weigand 6c5d5ce551 Allow target to handle STRICT floating-point nodes
The ISD::STRICT_ nodes used to implement the constrained floating-point
intrinsics are currently never passed to the target back-end, which makes
it impossible to handle them correctly (e.g. mark instructions are depending
on a floating-point status and control register, or mark instructions as
possibly trapping).

This patch allows the target to use setOperationAction to switch the action
on ISD::STRICT_ nodes to Legal. If this is done, the SelectionDAG common code
will stop converting the STRICT nodes to regular floating-point nodes, but
instead pass the STRICT nodes to the target using normal SelectionDAG
matching rules.

To avoid having the back-end duplicate all the floating-point instruction
patterns to handle both strict and non-strict variants, we make the MI
codegen explicitly aware of the floating-point exceptions by introducing
two new concepts:

- A new MCID flag "mayRaiseFPException" that the target should set on any
  instruction that possibly can raise FP exception according to the
  architecture definition.
- A new MI flag FPExcept that CodeGen/SelectionDAG will set on any MI
  instruction resulting from expansion of any constrained FP intrinsic.

Any MI instruction that is *both* marked as mayRaiseFPException *and*
FPExcept then needs to be considered as raising exceptions by MI-level
codegen (e.g. scheduling).

Setting those two new flags is straightforward. The mayRaiseFPException
flag is simply set via TableGen by marking all relevant instruction
patterns in the .td files.

The FPExcept flag is set in SDNodeFlags when creating the STRICT_ nodes
in the SelectionDAG, and gets inherited in the MachineSDNode nodes created
from it during instruction selection. The flag is then transfered to an
MIFlag when creating the MI from the MachineSDNode. This is handled just
like fast-math flags like no-nans are handled today.

This patch includes both common code changes required to implement the
new features, and the SystemZ implementation.

Reviewed By: andrew.w.kaylor

Differential Revision: https://reviews.llvm.org/D55506

llvm-svn: 362663
2019-06-05 22:33:10 +00:00
Michael Liao 9c70c574b4 [SelectionDAG] Enhance the simplification of `copyto` from `implicit-def`.
Summary:
- The current implementation simplifies the case where the source of
  `copyto` is `implicit-def`ed. However, it only works when that
  `implicit-def` is single-used since it detects that from
  `implicit-def` and cannot determine which destination vreg should be
  used if there are multiple uses.
- This patch changes that detection when `copyto` is being emitted. If
  that `copyto`'s source is defined from `implicit-def`, it simplifies
  it. Hence, it works even that `implicit-def` is multi-used.
- Except it simplifies the internal IR, it won't improve the quality of
  code generation. However, it helps to detect 'implicit-def` in a
  straight-forward manner in some passes, such as `si-i1-copies`. A test
  case is added.

Reviewers: sunfish, nhaehnle

Subscribers: jvesely, hiraditya, asbirlea, llvm-commits, yaxunl

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62342

llvm-svn: 361777
2019-05-27 18:26:29 +00:00
Alexander Timofeev ba447bae74 [AMDGPU] Divergence driven ISel. Assign register class for cross block values according to the divergence.
Details: To make instruction selection really divergence driven it is necessary to assign
             the correct register classes to the cross block values beforehand. For the divergent targets
             same value type requires different register classes dependent on the value divergence.

    Reviewers: rampitec, nhaehnle

    Differential Revision: https://reviews.llvm.org/D59990

    This commit was reverted because of the build failure.
    The reason was mlformed patch.
    Build failure fixed.

llvm-svn: 361741
2019-05-26 20:33:26 +00:00
Peter Collingbourne 3b93737446 Revert r361644, "[AMDGPU] Divergence driven ISel. Assign register class for cross block values according to the divergence."
Broke sanitizer bots:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/21694/steps/bootstrap%20clang/logs/stdio
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/32478/steps/check-llvm%20asan/logs/stdio

llvm-svn: 361688
2019-05-25 01:52:38 +00:00
Alexander Timofeev dffedea014 [AMDGPU] Divergence driven ISel. Assign register class for cross block values according to the divergence.
Details: To make instruction selection really divergence driven it is necessary to assign
         the correct register classes to the cross block values beforehand. For the divergent targets
         same value type requires different register classes dependent on the value divergence.

Reviewers: rampitec, nhaehnle

Differential Revision: https://reviews.llvm.org/D59990

llvm-svn: 361644
2019-05-24 15:32:18 +00:00
Chen Zheng b934fce613 [NFC] add/modify wrapper function for findRegisterDefOperand().
llvm-svn: 354438
2019-02-20 07:01:04 +00:00
Craig Topper 784929d045 Implementation of asm-goto support in LLVM
This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html

This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.

This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.

There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.

Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii

Differential Revision: https://reviews.llvm.org/D53765

llvm-svn: 353563
2019-02-08 20:48:56 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Krzysztof Parzyszek 5852aa44ae [SDAG] Clarify the origin of chain in REG_SEQUENCE in comment, NFC
llvm-svn: 349391
2018-12-17 20:30:20 +00:00
Krzysztof Parzyszek 6b01d35497 [SDAG] Ignore chain operand in REG_SEQUENCE when emitting instructions
llvm-svn: 349186
2018-12-14 20:14:12 +00:00
Jeremy Morse a06b163d5c [DebugInfo] Don't drop dbg.value's of nullptr
Currently, dbg.value's of "nullptr" are dropped when entering a SelectionDAG --
apparently just because of an oversight when recognising Values that are
constant (see PR39787). This patch adds ConstantPointerNull to the list of
constants that can be turned into DBG_VALUEs.

The matter of what bit-value a null pointer constant in LLVM has was raised
in this mailing list thread:

  http://lists.llvm.org/pipermail/llvm-dev/2018-December/128234.html

Where it transpires LLVM relies on (IR) null pointers being zero valued,
thus I've baked this assumption into the patch.

Differential Revision: https://reviews.llvm.org/D55227

llvm-svn: 348753
2018-12-10 12:04:08 +00:00
Jeremy Morse 045c67769d [DebugInfo] Emit undef DBG_VALUEs when SDNodes are optimised out
This is a fix for PR39896, where dbg.value's of SDNodes that have been
optimised out do not lead to "DBG_VALUE undef" instructions being created.
Such undef instructions are necessary to terminate earlier variable
ranges, otherwise variable values leak past the point where they're valid.

The "invalidated" flag of SDDbgValue is currently being abused to mean two
things:
 * The corresponding SDNode is now invalid
 * This SDDbgValue should not be emitted
Of which there are several legitimate combinations of meaning:
 * The SDNode has been invalidated and we should emit "DBG_VALUE undef"
 * The SDNode has been invalidated but the debug data was salvaged, don't
   emit anything for this SDDbgValue
 * This SDDbgValue has been emitted

This patch introduces distinct "Emitted" and "Invalidated" fields to the
SDDbgValue class, updates users accordingly, and generates "undef"
DBG_VALUEs for invalidated records. Awkwardly, there are circumstances
where we emit SDDbgValue's twice, specifically DebugInfo/X86/dbg-addr-dse.ll
which I've preserved.

Differential Revision: https://reviews.llvm.org/D55372

llvm-svn: 348751
2018-12-10 11:20:47 +00:00
Eli Friedman 2ac1162917 [ARM] Make InstrEmitter mark CPSR defs dead for Thumb1.
The "dead" markings allow existing target-independent optimizations,
like MachineSink, to trigger more frequently. The CPSR defs would have
eventually been marked dead by LiveVariables, so this only affects
optimizations before regalloc.

The ARMBaseInstrInfo.cpp change is fixing a bug which is only visible
with this change: the transform adds a use to an otherwise dead def
of CPSR. This is covered by existing regression tests.

thumb2-tbh.ll breaks for Thumb1 due to MachineLICM changing the
generated code; I'll fix it in D53452.

Differential Revision: https://reviews.llvm.org/D53453

llvm-svn: 345420
2018-10-26 19:32:24 +00:00
Michael Berg 894c39f770 Copy utilities updated and added for MI flags
Summary: This patch adds a GlobalIsel copy utility into MI for flags and updates the instruction emitter for the SDAG path.  Some tests show new behavior and I added one for GlobalIsel which mirrors an SDAG test for handling nsw/nuw.

Reviewers: spatel, wristow, arsenm

Reviewed By: arsenm

Subscribers: wdng

Differential Revision: https://reviews.llvm.org/D52006

llvm-svn: 342576
2018-09-19 18:52:08 +00:00
Chandler Carruth c73c0307fe [MI] Change the array of `MachineMemOperand` pointers to be
a generically extensible collection of extra info attached to
a `MachineInstr`.

The primary change here is cleaning up the APIs used for setting and
manipulating the `MachineMemOperand` pointer arrays so chat we can
change how they are allocated.

Then we introduce an extra info object that using the trailing object
pattern to attach some number of MMOs but also other extra info. The
design of this is specifically so that this extra info has a fixed
necessary cost (the header tracking what extra info is included) and
everything else can be tail allocated. This pattern works especially
well with a `BumpPtrAllocator` which we use here.

I've also added the basic scaffolding for putting interesting pointers
into this, namely pre- and post-instruction symbols. These aren't used
anywhere yet, they're just there to ensure I've actually gotten the data
structure types correct. I'll flesh out support for these in
a subsequent patch (MIR dumping, parsing, the works).

Finally, I've included an optimization where we store any single pointer
inline in the `MachineInstr` to avoid the allocation overhead. This is
expected to be the overwhelmingly most common case and so should avoid
any memory usage growth due to slightly less clever / dense allocation
when dealing with >1 MMO. This did require several ergonomic
improvements to the `PointerSumType` to reasonably support the various
usage models.

This also has a side effect of freeing up 8 bits within the
`MachineInstr` which could be repurposed for something else.

The suggested direction here came largely from Hal Finkel. I hope it was
worth it. ;] It does hopefully clear a path for subsequent extensions
w/o nearly as much leg work. Lots of thanks to Reid and Justin for
careful reviews and ideas about how to do all of this.

Differential Revision: https://reviews.llvm.org/D50701

llvm-svn: 339940
2018-08-16 21:30:05 +00:00
Chandler Carruth 66654b72c9 [SDAG] Remove the reliance on MI's allocation strategy for
`MachineMemOperand` pointers attached to `MachineSDNodes` and instead
have the `SelectionDAG` fully manage the memory for this array.

Prior to this change, the memory management was deeply confusing here --
The way the MI was built relied on the `SelectionDAG` allocating memory
for these arrays of pointers using the `MachineFunction`'s allocator so
that the raw pointer to the array could be blindly copied into an
eventual `MachineInstr`. This creates a hard coupling between how
`MachineInstr`s allocate their array of `MachineMemOperand` pointers and
how the `MachineSDNode` does.

This change is motivated in large part by a change I am making to how
`MachineFunction` allocates these pointers, but it seems like a layering
improvement as well.

This would run the risk of increasing allocations overall, but I've
implemented an optimization that should avoid that by storing a single
`MachineMemOperand` pointer directly instead of allocating anything.
This is expected to be a net win because the vast majority of uses of
these only need a single pointer.

As a side-effect, this makes the API for updating a `MachineSDNode` and
a `MachineInstr` reasonably different which seems nice to avoid
unexpected coupling of these two layers. We can map between them, but we
shouldn't be *surprised* at where that occurs. =]

Differential Revision: https://reviews.llvm.org/D50680

llvm-svn: 339740
2018-08-14 23:30:32 +00:00
Reid Kleckner 15e91c3235 [X86] Fix assertion in subreg extraction
This assert fires when attempting to extract a subregister from the
global PIC base register. This virtual register SD node is not in the
VRBaseMap, so we shouldn't call getVR to look it up there. If this is a
RegisterSDNode, we should be able to use the virtual register directly.

Fixes PR38385

llvm-svn: 339056
2018-08-06 21:16:16 +00:00
Vedant Kumar b572f64212 [DebugInfo] LowerDbgDeclare: Add derefs when handling CallInst users
LowerDbgDeclare inserts a dbg.value before each use of an address
described by a dbg.declare. When inserting a dbg.value before a CallInst
use, however, it fails to append DW_OP_deref to the DIExpression.

The DW_OP_deref is needed to reflect the fact that a dbg.value describes
a source variable directly (as opposed to a dbg.declare, which relies on
pointer indirection).

This patch adds in the DW_OP_deref where needed. This results in the
correct values being shown during a debug session for a program compiled
with ASan and optimizations (see https://reviews.llvm.org/D49520). Note
that ConvertDebugDeclareToDebugValue is already correct -- no changes
there were needed.

One complication is that SelectionDAG is unable to distinguish between
direct and indirect frame-index (FRAMEIX) SDDbgValues. This patch also
fixes this long-standing issue in order to not regress integration tests
relying on the incorrect assumption that all frame-index SDDbgValues are
indirect. This is a necessary fix: the newly-added DW_OP_derefs cannot
be lowered properly otherwise. Basically the fix prevents a direct
SDDbgValue with DIExpression(DW_OP_deref) from being dereferenced twice
by a debugger. There were a handful of tests relying on this incorrect
"FRAMEIX => indirect" assumption which actually had incorrect
DW_AT_locations: these are all fixed up in this patch.

Testing:

- check-llvm, and an end-to-end test using lldb to debug an optimized
  program.
- Existing unit tests for DIExpression::appendToStack fully cover the
  new DIExpression::append utility.
- check-debuginfo (the debug info integration tests)

Differential Revision: https://reviews.llvm.org/D49454

llvm-svn: 338069
2018-07-26 20:56:53 +00:00
Shiva Chen cd070cdc94 [DebugInfo] Convert intrinsic llvm.dbg.label to MachineInstr.
In order to convert LLVM IR to MachineInstr, we need a new TargetOpcode,
DBG_LABEL, to ‘lower’ intrinsic llvm.dbg.label. The patch
creates this new TargetOpcode and convert intrinsic llvm.dbg.label to
MachineInstr through SelectionDAG.

In SelectionDAG, debug information is stored in SDDbgInfo. We create a
new data member of SDDbgInfo for labels and use the new data member,
SDDbgLabel, to create DBG_LABEL MachineInstr.

The new DBG_LABEL MachineInstr uses label metadata from LLVM IR as its
parameter. So, the backend could get metadata information of labels from
DBG_LABEL MachineInstr.

Differential Revision: https://reviews.llvm.org/D45341

Patch by Hsiangkai Wang.

llvm-svn: 331842
2018-05-09 02:41:08 +00:00
Michael Berg 2dcf12ffd4 Mapping SDNode flags to MachineInstr flags
Summary: Providing the glue to map SDNode fast math sub flags to MachineInstr fast math sub flags.

Reviewers: spatel, arsenm, wristow

Reviewed By: spatel

Subscribers: wdng

Differential Revision: https://reviews.llvm.org/D46447

llvm-svn: 331567
2018-05-04 23:41:15 +00:00
Bjorn Pettersson abafca619b [SelectionDAG] Improve selection of DBG_VALUE using a PHI node result
Summary:
When building the selection DAG at ISel all PHI nodes are
selected and lowered to Machine Instruction PHI nodes before
we start to create any SDNodes. So there are no SDNodes for
values produced by the PHI nodes.

In the past when selecting a dbg.value intrinsic that uses
the value produced by a PHI node we have been handling such
dbg.value intrinsics as "dangling debug info". I.e. we have
not created a SDDbgValue node directly, because there is
no existing SDNode for the PHI result, instead we deferred
the creationg of a SDDbgValue until we found the first use
of the PHI result.

The old solution had a couple of flaws. The position of the
selected DBG_VALUE instruction would end up quite late in a
basic block, and for example not directly after the PHI node
as in the LLVM IR input. And in case there were no use at all
in the basic block the dbg.value could be dropped completely.

This patch introduces a new VREG kind of SDDbgValue nodes.
It is similar to a SDNODE kind of node, but it refers directly
to a virtual register and not a SDNode. When we do selection
for a dbg.value that is using the result of a PHI node we
can do a lookup of the virtual register directly (as it already
is determined for the PHI node) and create a SDDbgValue node
immediately instead of delaying the selection until we find a
use.

This should fix a problem with losing debug info at ISel
as seen in PR37234 (https://bugs.llvm.org/show_bug.cgi?id=37234).
It does not resolve PR37234 completely, because the debug info
is dropped later on in the BranchFolder (see D46184).

Reviewers: #debug-info, aprantl

Reviewed By: #debug-info, aprantl

Subscribers: rnk, gbedwell, aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D46129

llvm-svn: 331182
2018-04-30 14:37:39 +00:00
Stefan Maksimovic dc66ae78c6 [SelectionDAG] Provide adequate register class for RegisterSDNode
When adding operands to machine instructions in case of
RegisterSDNodes, generate a COPY node in case the register class
does not match the one in the instruction definition.

Differental Revision: https://reviews.llvm.org/D35561

llvm-svn: 324733
2018-02-09 13:55:25 +00:00
David Blaikie b3bde2ea50 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00
David Blaikie 3f833edc7c Target/TargetInstrInfo.h -> CodeGen/TargetInstrInfo.h to match layering
This header includes CodeGen headers, and is not, itself, included by
any Target headers, so move it into CodeGen to match the layering of its
implementation.

llvm-svn: 317647
2017-11-08 01:01:31 +00:00
Reid Kleckner e33c94f1b0 Add llvm.codeview.annotation to implement MSVC __annotation
Summary:
This intrinsic represents a label with a list of associated metadata
strings. It is modelled as reading and writing inaccessible memory so
that it won't be removed as dead code. I think the intention is that the
annotation strings should appear at most once in the debug info, so I
marked it noduplicate. We are allowed to inline code with annotations as
long as we strip the annotation, but that can be done later.

Reviewers: majnemer

Subscribers: eraman, llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D36904

llvm-svn: 312569
2017-09-05 20:14:58 +00:00
Adrian Prantl a617576bb1 Remove the unused dbg.value offset from SelectionDAG (NFC)
Followup to r309426.
rdar://problem/33580047

llvm-svn: 309436
2017-07-28 21:27:35 +00:00
Hiroshi Inoue a86c920b1e fix typos in comments and error messages; NFC
llvm-svn: 307533
2017-07-10 12:44:25 +00:00
Krzysztof Parzyszek c8e8e2a046 Move value type list from TargetRegisterClass to TargetRegisterInfo
Differential Revision: https://reviews.llvm.org/D31937

llvm-svn: 301234
2017-04-24 19:51:12 +00:00