Commit Graph

35 Commits

Author SHA1 Message Date
Guillaume Chatelet 3cc4835c00 Use Align for TFL::TransientStackAlignment
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: arsenm, dschuff, jyknight, sdardis, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, fedor.sergeev, jrtc27, atanasyan, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69216

llvm-svn: 375398
2019-10-21 08:31:25 +00:00
Guillaume Chatelet 882c43d703 [Alignment][NFC] Use Align for TargetFrameLowering/Subtarget
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68993

llvm-svn: 375084
2019-10-17 07:49:39 +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
Brendon Cahoon ac8fed68d5 [Hexagon] Implement noreturn optimization
Eliminate the stack frame in functions with the noreturn nounwind
attributes, and when the noreturn-stack-elim target feature is
enabled. This reduces the code and stack space needed for noreturn
functions.

Differential Revision: https://reviews.llvm.org/D54210

llvm-svn: 346532
2018-11-09 18:16:24 +00:00
David Blaikie 1be62f0327 Move TargetFrameLowering.h to CodeGen where it's implemented
This header already includes a CodeGen header and is implemented in
lib/CodeGen, so move the header there to match.

This fixes a link error with modular codegeneration builds - where a
header and its implementation are circularly dependent and so need to be
in the same library, not split between two like this.

llvm-svn: 317379
2017-11-03 22:32:11 +00:00
Krzysztof Parzyszek bea30c6286 Add "Restored" flag to CalleeSavedInfo
The liveness-tracking code assumes that the registers that were saved
in the function's prolog are live outside of the function. Specifically,
that registers that were saved are also live-on-exit from the function.
This isn't always the case as illustrated by the LR register on ARM.

Differential Revision: https://reviews.llvm.org/D36160

llvm-svn: 310619
2017-08-10 16:17:32 +00:00
Eugene Zelenko e4fc6ee790 [Hexagon] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 309230
2017-07-26 23:20:35 +00:00
Krzysztof Parzyszek 9eb75c4520 [Hexagon] Implement frame pointer elimination with -fomit-frame-pointer
It applies to leaf functions that are otherwise not required to have
a frame pointer.

llvm-svn: 306888
2017-06-30 21:21:40 +00:00
Krzysztof Parzyszek 717021772b Revert "[Hexagon] Handle decreasing of stack alignment in frame lowering"
This breaks passing of aligned function arguments.

llvm-svn: 306145
2017-06-23 19:47:04 +00:00
Krzysztof Parzyszek bb2fcd1921 [Hexagon] Handle decreasing of stack alignment in frame lowering
llvm-svn: 306124
2017-06-23 16:53:59 +00:00
Eugene Zelenko 26e8c7df3a [Hexagon] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 289907
2016-12-16 01:00:40 +00:00
Krzysztof Parzyszek ddafa2cd5f [Hexagon] Check for offset overflow when reserving scavenging slots
Scavenging slots were only reserved when pseudo-instruction expansion in
frame lowering created new virtual registers. It is possible to still
need a scavenging slot even if no virtual registers were created, in cases
where the stack is large enough to overflow instruction offsets.

llvm-svn: 277355
2016-08-01 17:15:30 +00:00
Krzysztof Parzyszek a34d639549 [Hexagon] Add saved callee-saved registers as live-in in non-wrapped blocks
The callee-saved registers that are saved in a function are not pristine,
and so they can be defined and used. In case of shrink-wrapping though,
there are blocks that are outside of the save/restore range, and in those
blocks the saved registers must be treated as pristine. To avoid any uses
of these registers, add them as live-in in all those blocks.
This was already done for blocks reaching function exits after restore,
add code that does the same for blocks reached from the function entry
before save.

llvm-svn: 276886
2016-07-27 16:26:39 +00:00
Krzysztof Parzyszek da0b9a959e [Hexagon] Enable the post-RA scheduler
The aggressive anti-dependency breaker can rename the restored callee-
saved registers. To prevent this, mark these registers are live on all
paths to the return/tail-call instructions, and add implicit use operands
for them to these instructions.

llvm-svn: 270898
2016-05-26 19:44:28 +00:00
Krzysztof Parzyszek e8e754da74 [Hexagon] Register save/restore functions do not follow regular conventions
Do not mark them as modifying any of the volatile registers by default.

llvm-svn: 267433
2016-04-25 17:49:44 +00:00
Hans Wennborg e1a2e90ffa Change eliminateCallFramePseudoInstr() to return an iterator
This will become necessary in a subsequent change to make this method
merge adjacent stack adjustments, i.e. it might erase the previous
and/or next instruction.

It also greatly simplifies the calls to this function from Prolog-
EpilogInserter. Previously, that had a bunch of logic to resume iteration
after the call; now it just continues with the returned iterator.

Note that this changes the behaviour of PEI a little. Previously,
it attempted to re-visit the new instruction created by
eliminateCallFramePseudoInstr(). That code was added in r36625,
but I can't see any reason for it: the new instructions will obviously
not be pseudo instructions, they will not have FrameIndex operands,
and we have already accounted for the stack adjustment.

Differential Revision: http://reviews.llvm.org/D18627

llvm-svn: 265036
2016-03-31 18:33:38 +00:00
Krzysztof Parzyszek c9d4caa32c [Hexagon] Add support for run-time stack overflow checking
Patch by Sundeep Kushwaha.

llvm-svn: 264328
2016-03-24 20:20:07 +00:00
Krzysztof Parzyszek 7793ddb043 [Hexagon] Optimize stack slot spills
Replace spills to memory with spills to registers, if possible. This
applies mostly to predicate registers (both scalar and vector), since
they are very limited in number. A spill of a predicate register may
happen even if there is a general-purpose register available. In cases
like this the stack spill/reload may be eliminated completely.

This optimization will consider all stack objects, regardless of where
they came from and try to match the live range of the stack slot with
a dead range of a register from an appropriate register class.

llvm-svn: 260758
2016-02-12 22:53:35 +00:00
Krzysztof Parzyszek 996ad1fa00 [Hexagon] Replace expansion of spill pseudo-instructions in frame lowering
Rewrite the code to handle all pseudo-instructions in a single pass.

This temporarily reverts spill slot optimization that used general-
purpose registers to hold values of spilled predicate registers.

llvm-svn: 260696
2016-02-12 18:19:53 +00:00
Krzysztof Parzyszek 7b413c6c63 [Hexagon] Use general purpose registers to spill pred/mod registers into
Patch by Tobias Edler Von Koch.

llvm-svn: 258527
2016-01-22 19:15:58 +00:00
Benjamin Kramer 755e502952 Add missing override noticed by Clang's -Winconsistent-missing-override.
llvm-svn: 250720
2015-10-19 18:41:23 +00:00
Krzysztof Parzyszek 23920ec95d [Hexagon] Fix debug information for local objects
- Isolate the check for the existence of a stack frame into hasFP.
- Implement getFrameIndexReference for DWARF address computation.
- Use getFrameIndexReference for offset computation in eliminateFrameIndex.
- Preserve debug information for dynamically allocated stack objects.
- Prefer FP to access local objects at -O0.
- Add experimental code to skip allocframe when not strictly necessary
  (disabled by default).

llvm-svn: 250718
2015-10-19 18:30:27 +00:00
Krzysztof Parzyszek db8677067c [Hexagon] Delay emission of CFI instructions
Emit the CFI instructions after all code transformation have been done.
This will avoid any interference between CFI instructions and packetization.

llvm-svn: 250714
2015-10-19 17:46:01 +00:00
James Y Knight 5567bafe93 Remove redundant TargetFrameLowering::getFrameIndexOffset virtual
function.

This was the same as getFrameIndexReference, but without the FrameReg
output.

Differential Revision: http://reviews.llvm.org/D12042

llvm-svn: 245148
2015-08-15 02:32:35 +00:00
Matthias Braun 0256486532 PrologEpilogInserter: Rewrite API to determine callee save regsiters.
This changes TargetFrameLowering::processFunctionBeforeCalleeSavedScan():

- Rename the function to determineCalleeSaves()
- Pass a bitset of callee saved registers by reference, thus avoiding
  the function-global PhysRegUsed bitset in MachineRegisterInfo.
- Without PhysRegUsed the implementation is fine tuned to not save
  physcial registers which are only read but never modified.

Related to rdar://21539507

Differential Revision: http://reviews.llvm.org/D10909

llvm-svn: 242165
2015-07-14 17:17:13 +00:00
Alexander Kornienko f00654e31b Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
2015-06-23 09:49:53 +00:00
Alexander Kornienko 70bc5f1398 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
Quentin Colombet 61b305edfd [ShrinkWrap] Add (a simplified version) of shrink-wrapping.
This patch introduces a new pass that computes the safe point to insert the
prologue and epilogue of the function.
The interest is to find safe points that are cheaper than the entry and exits
blocks.

As an example and to avoid regressions to be introduce, this patch also
implements the required bits to enable the shrink-wrapping pass for AArch64.


** Context **

Currently we insert the prologue and epilogue of the method/function in the
entry and exits blocks. Although this is correct, we can do a better job when
those are not immediately required and insert them at less frequently executed
places.
The job of the shrink-wrapping pass is to identify such places.


** Motivating example **

Let us consider the following function that perform a call only in one branch of
a if:
define i32 @f(i32 %a, i32 %b)  {
 %tmp = alloca i32, align 4
 %tmp2 = icmp slt i32 %a, %b
 br i1 %tmp2, label %true, label %false

true:
 store i32 %a, i32* %tmp, align 4
 %tmp4 = call i32 @doSomething(i32 0, i32* %tmp)
 br label %false

false:
 %tmp.0 = phi i32 [ %tmp4, %true ], [ %a, %0 ]
 ret i32 %tmp.0
}

On AArch64 this code generates (removing the cfi directives to ease
readabilities):
_f:                                     ; @f
; BB#0:
  stp x29, x30, [sp, #-16]!
  mov  x29, sp
  sub sp, sp, #16             ; =16
  cmp  w0, w1
  b.ge  LBB0_2
; BB#1:                                 ; %true
  stur  w0, [x29, #-4]
  sub x1, x29, #4             ; =4
  mov  w0, wzr
  bl  _doSomething
LBB0_2:                                 ; %false
  mov  sp, x29
  ldp x29, x30, [sp], #16
  ret

With shrink-wrapping we could generate:
_f:                                     ; @f
; BB#0:
  cmp  w0, w1
  b.ge  LBB0_2
; BB#1:                                 ; %true
  stp x29, x30, [sp, #-16]!
  mov  x29, sp
  sub sp, sp, #16             ; =16
  stur  w0, [x29, #-4]
  sub x1, x29, #4             ; =4
  mov  w0, wzr
  bl  _doSomething
  add sp, x29, #16            ; =16
  ldp x29, x30, [sp], #16
LBB0_2:                                 ; %false
  ret

Therefore, we would pay the overhead of setting up/destroying the frame only if
we actually do the call.


** Proposed Solution **

This patch introduces a new machine pass that perform the shrink-wrapping
analysis (See the comments at the beginning of ShrinkWrap.cpp for more details).
It then stores the safe save and restore point into the MachineFrameInfo
attached to the MachineFunction.
This information is then used by the PrologEpilogInserter (PEI) to place the
related code at the right place. This pass runs right before the PEI.

Unlike the original paper of Chow from PLDI’88, this implementation of
shrink-wrapping does not use expensive data-flow analysis and does not need hack
to properly avoid frequently executed point. Instead, it relies on dominance and
loop properties.

The pass is off by default and each target can opt-in by setting the
EnableShrinkWrap boolean to true in their derived class of TargetPassConfig.
This setting can also be overwritten on the command line by using
-enable-shrink-wrap.

Before you try out the pass for your target, make sure you properly fix your
emitProlog/emitEpilog/adjustForXXX method to cope with basic blocks that are not
necessarily the entry block.


** Design Decisions **

1. ShrinkWrap is its own pass right now. It could frankly be merged into PEI but
for debugging and clarity I thought it was best to have its own file.
2. Right now, we only support one save point and one restore point. At some
point we can expand this to several save point and restore point, the impacted
component would then be:
- The pass itself: New algorithm needed.
- MachineFrameInfo: Hold a list or set of Save/Restore point instead of one
  pointer.
- PEI: Should loop over the save point and restore point.
Anyhow, at least for this first iteration, I do not believe this is interesting
to support the complex cases. We should revisit that when we motivating
examples.

Differential Revision: http://reviews.llvm.org/D9210

<rdar://problem/3201744>

llvm-svn: 236507
2015-05-05 17:38:16 +00:00
Krzysztof Parzyszek 876a19d855 [Hexagon] Shrink-wrap stack frame (Hexagon-specific)
llvm-svn: 235603
2015-04-23 16:05:39 +00:00
Krzysztof Parzyszek 4fa2a9f7fd [Hexagon] Overhaul of stack object allocation
- Use static allocation for aligned stack objects.
- Simplify dynamic stack object allocation.
- Simplify elimination of frame-indices.

llvm-svn: 235521
2015-04-22 16:43:53 +00:00
Benjamin Kramer a7c40ef022 Canonicalize header guards into a common format.
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)

Changes made by clang-tidy with minor tweaks.

llvm-svn: 215558
2014-08-13 16:26:38 +00:00
Eric Christopher a68f376333 Remove unnecessary caching of the subtarget for HexagonFrameLowering and remove the unused constructor argument.
llvm-svn: 211819
2014-06-27 00:13:47 +00:00
Craig Topper 906c2cd2e6 [C++11] Add 'override' keywords and remove 'virtual'. Additionally add 'final' and leave 'virtual' on some methods that are marked virtual without overriding anything and have no obvious overrides themselves. Hexagon edition
llvm-svn: 207508
2014-04-29 07:58:16 +00:00
Eli Bendersky 8da87163ca Move the eliminateCallFramePseudoInstr method from TargetRegisterInfo
to TargetFrameLowering, where it belongs. Incidentally, this allows us
to delete some duplicated (and slightly different!) code in TRI.

There are potentially other layering problems that can be cleaned up
as a result, or in a similar manner.

The refactoring was OK'd by Anton Korobeynikov on llvmdev.

Note: this touches the target interfaces, so out-of-tree targets may
be affected.

llvm-svn: 175788
2013-02-21 20:05:00 +00:00
Tony Linthicum 1213a7a57f Hexagon backend support
llvm-svn: 146412
2011-12-12 21:14:40 +00:00