Callee saved registers should always be phyiscal registers. They are
often passed directly to other functions that take MCRegister like
getMinimalPhysRegClass or TargetRegisterClass::contains.
Unfortunately, sometimes the MCRegister is compared to a Register which
gave an ambiguous comparison error when the MCRegister is on the LHS.
Adding a MCRegister==Register comparison operator created more ambiguous
comparison errors elsewhere. These cases were usually comparing against
a base or frame pointer register that is a physical register in a
Register. For those I added an explicit conversion of Register to
MCRegister to fix the error.
An optimization was added that tries to move the uses of the mflr
instruction away from the instruction itself. However, this doesn't work
when we are using the hashst instruction because that instruction needs
to be run before the stack frame is obtained.
This patch disables moving instructions away from the mflr in the case
where ROP protection is being used.
---------
Co-authored-by: Lei Huang <lei@ca.ibm.com>
This patch utilizes getReservedRegs() to find asm clobberable registers.
And to make the result of getReservedRegs() accurate, this patch
implements the todo, which is to make r2 allocatable on AIX for some
leaf functions.
Some targets (e.g. PPC and Hexagon) already did this. I think it's best
to do this consistently so that frontend authors don't run into
inconsistent results when they emit `naked` functions. For example, in
Zig, we had to change our emit code to also set `frame-pointer=none` to
get reliable results across targets.
Note: I don't have commit access.
When the base pointer r30 is used to hold the stack pointer, r30 is
spilled in the prologue. On AIX registers are saved from highest to
lowest, so r31 also needs to be saved.
Fixes https://github.com/llvm/llvm-project/issues/96411
MachineFunction's probably should not include a backreference to
the owning MachineModuleInfo. Most of these references were used
just to query the MCContext, which MachineFunction already directly
stores. Other contexts are using it to query the LLVMContext, which
can already be accessed through the IR function reference.
https://github.com/llvm/llvm-project/pull/79940 put calls to
recomputeLiveIns into
a loop, to repeatedly call the function until the computation converges.
However,
this repeats a lot of code. This changes moves the loop into a function
to simplify
the handling.
Note that this changes the order in which recomputeLiveIns is called.
For example,
```
bool anyChange = false;
do {
anyChange = recomputeLiveIns(*ExitMBB) || recomputeLiveIns(*LoopMBB);
} while (anyChange);
```
only begins to recompute the live-ins for LoopMBB after the computation
for ExitMBB
has converged. With this change, all basic blocks have a recomputation
of the live-ins
for each loop iteration. This can result in less or more calls,
depending on the
situation.
Delete the code that skips the CFI for the condition register on ELF32.
The code checked !MustSaveCR, which happened only when
Subtarget.is32BitELFABI(), where spillCalleeSavedRegisters is spilling
cr in a different way. The spill was missing CFI. After deleting this
code, a spill of cr2 to cr4 gets CFI in the same way as a spill of r14
to r31.
Fixes#83094
This is a fix for the regression seen in
https://github.com/llvm/llvm-project/pull/79498
> Currently, the way that recomputeLiveIns works is that it will
recompute the livein registers for that MachineBasicBlock but it matters
what order you call recomputeLiveIn which can result in incorrect
register allocations down the line.
Now we do not recompute the entire CFG but we do ensure that the newly
added MBB do reach convergence.
Currently, the way that recomputeLiveIns works is that it will recompute
the livein registers for that MachineBasicBlock but it matters what
order you call recomputeLiveIn which can result in incorrect register
allocations down the line.
This PR fixes that by simply recomputing the liveins for the entire CFG
until convergence is achieved. This makes it harder to introduce subtle
bugs which alter liveness.
This was modifying a container as it iterated it, which tripped a check
in libstdc++'s debug checks.
Instead, just assign to the item via the reference we already have.
This fixes the following expensive checks failures on my machine:
LLVM :: CodeGen/PowerPC/fp-strict.ll
LLVM :: CodeGen/PowerPC/pr55463.ll
LLVM :: CodeGen/PowerPC/register-pressure.ll
LLVM :: CodeGen/PowerPC/spe.ll
Which are some of the tests noted by #68594.
Track the live register state immediately before, instead of after,
MBBI. This makes it simple to track the state at the start or end of a
basic block without a separate (and poorly named) Tracking flag.
This changes the API of the backward(MachineBasicBlock::iterator I)
method, which now recedes to the state just before, instead of just
after, *I. Some clients are simplified by this change.
There is one small functional change shown in the lit tests where
multiple spilled registers all need to be reloaded before the same
instruction. The reloads will now be inserted in the opposite order.
This should not affect correctness.
PPC64 allows stack size up to ((2^63)-1) bytes. Currently llc reports
```
warning: stack frame size (4294967568) exceeds limit (4294967295) in function 'main'
```
if the stack allocated is larger than 4G.
With D134950, targets get notified when a virtual register is created and/or
cloned. Targets can do the needful with the delegate callback. AMDGPU propagates
the virtual register flags maintained in the target file itself. They are useful
to identify a certain type of machine operands while inserting spill stores and
reloads. Since RegAllocFast spills the physical register itself, there is no way
its virtual register can be mapped back to retrieve the flags. It can be solved
by passing the virtual register as an additional argument. This argument has no
use when the spill interfaces are called during the greedy allocator or even the
PrologEpilogInserter and can pass a null register in such cases.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D138656
mflr is kind of expensive on Power version smaller than 10, so we should
schedule the store for the mflr's def away from mflr.
In epilogue, the expensive mtlr has no user for its def, so it doesn't
matter that the load and the mtlr are back-to-back.
Reviewed By: RolandF
Differential Revision: https://reviews.llvm.org/D137423
LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.
Change call sites to use `std::size` instead.
Differential Revision: https://reviews.llvm.org/D133429
Support allocation of huge stack frame(>2g) on PPC64.
For ELFv2 ABI on Linux, quoted from the spec 2.2.3.1 General Stack Frame Requirements
> There is no maximum stack frame size defined.
On AIX, XL allows such huge frame.
Reviewed By: #powerpc, nemanjai
Differential Revision: https://reviews.llvm.org/D107886
Add the calling convention for the vector pair registers.
These registers overlap with the vector registers.
Part of an original patch by: Lei Huang
Reviewed By: nemanjai, #powerpc
Differential Revision: https://reviews.llvm.org/D117225
This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https://reviews.llvm.org/D121169
This reverts commit ef8206320769ad31422a803a0d6de6077fd231d2.
- It conflicts with the existing llvm::size in STLExtras, which will now
never be called.
- Calling it without llvm:: breaks C++17 compat
Add support for Return Oriented Programming (ROP) protection for 32 bit.
This patch also adds a testing for AIX on both 64 and 32 bit.
Reviewed By: amyk
Differential Revision: https://reviews.llvm.org/D111362
This is the first step to enable PPC64 support huge frame size(>2G). Also fix an assertion error for frame size, i.e.,`int x; !isInt<32>(x);` should be always evaluated false, so the guard code for frame size is impossible to hit.
Reviewed By: jsji
Differential Revision: https://reviews.llvm.org/D107435
When `-fstack-clash-protection` is enabled and stack has to be realigned, some parts of redzone is written prior the probe, so probe might overwrite content already written in redzone. To avoid it, we have to make sure the first probe is at full probe size or is the last probe so that we can skip redzone.
It also fixes violation of ABI under PPC where `r1` isn't updated atomically.
This fixes https://bugs.llvm.org/show_bug.cgi?id=49903.
Reviewed By: jsji
Differential Revision: https://reviews.llvm.org/D100290
