This changes a couple of calls to LiveRegs.contains to
!LiveRegs.available, one in Thumb1FrameLoweringInfo (which modifies a
test to look more correct to me, given r7 should be the frame pointer so
is not available), and another in the ARMLoadStoreOptimizer, that I
don't have a test for, it was just found by inspection.
Differential Revision: https://reviews.llvm.org/D107454
getFramePointerReg only depends on information in ARMSubtarget,
so move it in there so it can be accessed from more places.
Make use of ARMSubtarget::getFramePointerReg to remove duplicated code.
The main use of useR7AsFramePointer is getFramePointerReg, so inline it.
Differential Revision: https://reviews.llvm.org/D104476
Currently needsStackRealignment returns false if canRealignStack returns false.
This means that the behavior of needsStackRealignment does not correspond to
it's name and description; a function might need stack realignment, but if it
is not possible then this function returns false. Furthermore,
needsStackRealignment is not virtual and therefore some backends have made use
of canRealignStack to indicate whether a function needs stack realignment.
This patch attempts to clarify the situation by separating them and introducing
new names:
- shouldRealignStack - true if there is any reason the stack should be
realigned
- canRealignStack - true if we are still able to realign the stack (e.g. we
can still reserve/have reserved a frame pointer)
- hasStackRealignment = shouldRealignStack && canRealignStack (not target
customisable)
Targets can now override shouldRealignStack to indicate that stack realignment
is required.
This change will make it easier in a future change to handle the case where we
need to realign the stack but can't do so (for example when the register
allocator creates an aligned spill after the frame pointer has been
eliminated).
Differential Revision: https://reviews.llvm.org/D98716
Change-Id: Ib9a4d21728bf9d08a545b4365418d3ffe1af4d87
This patch implements the final bits of CMSE code generation:
* emit special linker symbols
* restrict parameter passing to no use memory
* emit BXNS and BLXNS instructions for returns from non-secure entry
functions, and non-secure function calls, respectively
* emit code to save/restore secure floating-point state around calls
to non-secure functions
* emit code to save/restore non-secure floating-pointy state upon
entry to non-secure entry function, and return to non-secure state
* emit code to clobber registers not used for arguments and returns
* when switching to no-secure state
Patch by Momchil Velikov, Bradley Smith, Javed Absar, David Green,
possibly others.
Differential Revision: https://reviews.llvm.org/D76518
This patch implements the final bits of CMSE code generation:
* emit special linker symbols
* restrict parameter passing to not use memory
* emit BXNS and BLXNS instructions for returns from non-secure entry
functions, and non-secure function calls, respectively
* emit code to save/restore secure floating-point state around calls
to non-secure functions
* emit code to save/restore non-secure floating-pointy state upon
entry to non-secure entry function, and return to non-secure state
* emit code to clobber registers not used for arguments and returns
when switching to no-secure state
Patch by Momchil Velikov, Bradley Smith, Javed Absar, David Green,
possibly others.
Differential Revision: https://reviews.llvm.org/D76518
If the stack pointer is altered for local variables and we are generating
Thumb2 execute-only code the .pad directive is missing.
Usually the size of the adjustment is stored in a PC-relative location
and loaded into a register which is then added to the stack pointer.
However when we are generating execute-only code code the size of the
adjustment is instead generated using the MOVW/MOVT instruction pair.
As a by product of handling the execute-only case this also fixes an
existing issue that in the none execute-only case the .pad directive was
generated against the load of the constant to a register instruction,
instead of the instruction which adds the register to the stack pointer.
Differential Revision: https://reviews.llvm.org/D76849
When optimising for code size at the expense of performance, it is often
worth saving and restoring some of r0-r3, if IPRA will be able to take
advantage of them. This doesn't cost any extra code size if we already
have a PUSH/POP pair, and increases the number of available registers
across any calls to the function.
We already have an optimisation which tries fold the subtract/add of the
SP into the PUSH/POP by using extra registers, which somewhat conflicts
with this. I've made the new optimisation less aggressive in cases where
the existing one is likely to trigger, which gives better results than
either of these optimisations by themselves.
Differential revision: https://reviews.llvm.org/D69936
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, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76348
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
There were two issues here: one, some of the relevant instructions were
missing the expected "FrameSetup" flag, and two,
ARMAsmPrinter::EmitUnwindingInstruction wasn't expecting "mov"
instructions in the prologue.
I'm sticking the additional state into ARMFunctionInfo so it's obvious
it only applies to the current function.
I considered a few alternative approaches where we would compute the
correct unwind information as part of the prologue/epilogue lowering,
but it seems like a lot of work to introduce pseudo-instructions, and
the current code seems to be reliable enough.
Fixes https://bugs.llvm.org/show_bug.cgi?id=42408.
Differential Revision: https://reviews.llvm.org/D63964
llvm-svn: 364970
The current implementation of ThumbRegisterInfo::saveScavengerRegister
is bad for two reasons: one, it's buggy, and two, it blocks using R12
for other optimizations. So this patch gets rid of it, and adds the
necessary support for using an ordinary emergency spill slot on Thumb1.
(Specifically, I think saveScavengerRegister was broken by r305625, and
nobody noticed for two years because the codepath is almost never used.
The new code will also probably not be used much, but it now has better
tests, and if we fail to emit a necessary emergency spill slot we get a
reasonable error message instead of a miscompile.)
A rough outline of the changes in the patch:
1. Gets rid of ThumbRegisterInfo::saveScavengerRegister.
2. Modifies ARMFrameLowering::determineCalleeSaves to allocate an
emergency spill slot for Thumb1.
3. Implements useFPForScavengingIndex, so the emergency spill slot isn't
placed at a negative offset from FP on Thumb1.
4. Modifies the heuristics for allocating an emergency spill slot to
support Thumb1. This includes fixing ExtraCSSpill so we don't try to
use "lr" as a substitute for allocating an emergency spill slot.
5. Allocates a base pointer in more cases, so the emergency spill slot
is always accessible.
6. Modifies ARMFrameLowering::ResolveFrameIndexReference to compute the
right offset in the new cases where we're forcing a base pointer.
7. Ensures we never generate a load or store with an offset outside of
its frame object. This makes the heuristics more straightforward.
8. Changes Thumb1 prologue and epilogue emission so it never uses
register scavenging.
Some of the changes to the emergency spill slot heuristics in
determineCalleeSaves affect ARM/Thumb2; hopefully, they should allow
the compiler to avoid allocating an emergency spill slot in cases
where it isn't necessary. The rest of the changes should only affect
Thumb1.
Differential Revision: https://reviews.llvm.org/D63677
llvm-svn: 364490
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
This patch allows `r7` to be used, regardless of its use as a frame pointer, as
a temporary register when popping `lr`, and also falls back to using a high
temporary register if, for some reason, we weren't able to find a suitable low
one.
Differential revision: https://reviews.llvm.org/D40961
Fixes https://bugs.llvm.org/show_bug.cgi?id=35481
llvm-svn: 321989
The commit https://reviews.llvm.org/rL318143 computes incorrectly to offset to
restore LR from.
The number of tPOP operands is 2 (condition) + 2 (implicit def and use of SP) +
count of the popped registers. We need to load LR from just past the last
register, hence the correct offset should be either getNumOperands() - 4 and
getNumExplicitOperands() - 2 (multiplied by 4).
Differential revision: https://reviews.llvm.org/D40305
llvm-svn: 319014
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
When we emit a tail call for Armv8-M, but then discover that the caller needs to
save/restore `LR`, we convert the tail call to an ordinary one, since restoring
`LR` takes extra instructions, which may negate the benefits of the tail
call. If the callee, however, takes stack arguments, this conversion is
incorrect, since nothing has been done to pass the stack arguments.
Thus the patch reverts https://reviews.llvm.org/rL294000
Also, we improve the instruction sequence for popping `LR` in the case when we
couldn't immediately find a scratch low register, but we can use as a temporary
one of the callee-saved low registers and restore `LR` before popping other
callee-saves.
Differential Revision: https://reviews.llvm.org/D39599
llvm-svn: 318143
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
This patch implements dynamic stack (re-)alignment for 16-bit Thumb. When
targeting processors, which support only the 16-bit Thumb instruction set
the compiler ignores the alignment attributes of automatic variables and may
silently generate incorrect code.
Differential revision: https://reviews.llvm.org/D38143
llvm-svn: 316289
LR is an untypical callee saved register in that it is restored into a
different register (PC) and thus does not live-out of the return block.
This case requires the `Restored` flag in CalleeSavedInfo to be cleared.
This fixes a number of cases where this wasn't handled correctly yet.
llvm-svn: 314471
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
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
In r300196 several methods were added to TarfetInstrInfo to access
data stored with call frame setup/destroy instructions. This change
replaces calls to getOperand with calls to such special methods in
ARM target.
Differential Revision: https://reviews.llvm.org/D32127
llvm-svn: 300655
Summary:
The tail call optimisation is performed before register allocation, so
at that point we don't know if LR is being spilt or not. If LR was spilt
to the stack, then we cannot do a tail call optimisation. That would
involve popping back into LR which is not possible in Thumb1 code.
Reviewers: rengolin, jmolloy, rovka, olista01
Reviewed By: olista01
Subscribers: llvm-commits, aemerson
Differential Revision: https://reviews.llvm.org/D29020
llvm-svn: 294000
Summary:
In this function, virtual registers can be introduced (for example
through calls to emitThumbRegPlusImmInReg). doScavengeFrameVirtualRegs
will replace those virtual registers with concrete registers later on
in PrologEpilogInserter, which sets NoVRegs again.
This patch fixes the Codegen/Thumb/segmented-stacks.ll test case which
failed with expensive checks.
https://llvm.org/bugs/show_bug.cgi?id=27484
Reviewers: rnk, bkramer, olista01
Reviewed By: olista01
Subscribers: llvm-commits, rengolin
Differential Revision: https://reviews.llvm.org/D28829
llvm-svn: 292372
Rename from addOperand to just add, to match the other method that has been
added to MachineInstrBuilder for adding more than just 1 operand.
See https://reviews.llvm.org/D28057 for the whole discussion.
Differential Revision: https://reviews.llvm.org/D28556
llvm-svn: 291891
Replace all uses of AddDefaultPred with MachineInstrBuilder::add(predOps()).
This makes the code building MachineInstrs more readable, because it allows us
to write code like:
MIB.addSomeOperand(blah)
.add(predOps())
.addAnotherOperand(blahblah)
instead of
AddDefaultPred(MIB.addSomeOperand(blah))
.addAnotherOperand(blahblah)
This commit also adds the predOps helper in the ARM backend, as well as the add
method taking a variable number of operands to the MachineInstrBuilder.
The transformation has been done mostly automatically with a custom tool based
on Clang AST Matchers + RefactoringTool.
Differential Revision: https://reviews.llvm.org/D28555
llvm-svn: 291890
This is per function data so it is better kept at the function instead
of the module.
This is a necessary step to have machine module passes work properly.
Differential Revision: https://reviews.llvm.org/D27185
llvm-svn: 288291
Reverts r283938 to reinstate r283867 with a fix.
The original change had an ArrayRef referring to a destroyed temporary
initializer list. Use plain C arrays instead.
llvm-svn: 283942
The high registers are not allocatable in Thumb1 functions, but they
could still be used by inline assembly, so we need to save and restore
the callee-saved high registers (r8-r11) in the prologue and epilogue.
This is complicated by the fact that the Thumb1 push and pop
instructions cannot access these registers. Therefore, we have to move
them down into low registers before pushing, and move them back after
popping into low registers.
In most functions, we will have low registers that are also being
pushed/popped, which we can use as the temporary registers for
saving/restoring the high registers. However, this is not guaranteed, so
we may need to push some extra low registers to ensure that the high
registers can be saved/restored. For correctness, it would be sufficient
to use just one low register, but if we have enough low registers
available then we only need one push/pop instruction, rather than one
per high register.
We can also use the argument/return registers when they are not live,
and the link register when saving (but not restoring), reducing the
number of extra registers we need to push.
There are still a few extreme edge cases where we need two push/pop
instructions, because not enough low registers can be made live in the
prologue or epilogue.
In addition to the regression tests included here, I've also tested this
using a script to generate functions which clobber different
combinations of registers, have different numbers of argument and return
registers (including variadic arguments), allocate different fixed sized
objects on the stack, and do or don't use variable sized allocas and the
__builtin_return_address intrinsic (all of which affect the available
registers in the prologue and epilogue). I ran these functions in a test
harness which verifies that all of the callee-saved registers are
correctly preserved.
Differential Revision: https://reviews.llvm.org/D24228
llvm-svn: 283867
There is not an official documented ABI for frame pointers in Thumb2,
but we should try to emit something which is useful.
We use r7 as the frame pointer for Thumb code, which currently means
that if a function needs to save a high register (r8-r11), it will get
pushed to the stack between the frame pointer (r7) and link register
(r14). This means that while a stack unwinder can follow the chain of
frame pointers up the stack, it cannot know the offset to lr, so does
not know which functions correspond to the stack frames.
To fix this, we need to push the callee-saved registers in two batches,
with the first push saving the low registers, fp and lr, and the second
push saving the high registers. This is already implemented, but
previously only used for iOS. This patch turns it on for all Thumb2
targets when frame pointers are required by the ABI, and the frame
pointer is r7 (Windows uses r11, so this isn't a problem there). If
frame pointer elimination is enabled we still emit a single push/pop
even if we need a frame pointer for other reasons, to avoid increasing
code size.
We must also ensure that lr is pushed to the stack when using a frame
pointer, so that we end up with a complete frame record. Situations that
could cause this were rare, because we already push lr in most
situations so that we can return using the pop instruction.
Differential Revision: https://reviews.llvm.org/D23516
llvm-svn: 279506
This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.
llvm-svn: 278902
Remove remaining implicit conversions from MachineInstrBundleIterator to
MachineInstr* from the ARM backend. In most cases, I made them less attractive
by preferring MachineInstr& or using a ranged-based for loop.
Once all the backends are fixed I'll make the operator explicit so that this
doesn't bitrot back.
llvm-svn: 274920
This used to be free, copying and moving DebugLocs became expensive
after the metadata rewrite. Passing by reference eliminates a ton of
track/untrack operations. No functionality change intended.
llvm-svn: 272512
David Green