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 ef82063207.
- 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
Added hashst to the prologue and hashchk to the epilogue.
The hash for the prologue and epilogue must always be stored as the first
element in the local variable space on the stack.
Reviewed By: nemanjai, #powerpc
Differential Revision: https://reviews.llvm.org/D99377
The stack frame update code does not take into consideration spilling
to registers for callee saved registers. The option -ppc-enable-pe-vector-spills
turns on spilling to registers for callee saved registers and may expose a bug
in the code that moves a stack frame pointer update instruction.
Reviewed By: nemanjai, #powerpc
Differential Revision: https://reviews.llvm.org/D101366
This patch exploits mtvsrdd instruction (available in ISA3.0+) to save
two callee-saved GPR registers into a single VSR, making it more
efficient.
Reviewed By: jsji, nemanjai
Differential Revision: https://reviews.llvm.org/D62565
Summary:
Currently Shrinkwrap is not enabled on AIX.
This patch enables shrink wrap on 32 and 64 bit AIX, and 64 bit ELF.
Reviewed By: sfertile, nemanjai
Differential Revision: https://reviews.llvm.org/D95094
On subtargets that have a red zone, we will copy the stack pointer to the base
pointer in the prologue prior to updating the stack pointer. There are no other
updates to the base pointer after that. This suggests that we should be able to
restore the stack pointer from the base pointer rather than loading it from the
back chain or adding the frame size back to either the stack pointer or the
frame pointer.
This came about because functions that call setjmp need to restore the SP from
the FP because the back chain might have been clobbered
(see https://reviews.llvm.org/D92906). However, if the stack is realigned, the
restored SP might be incorrect (which is what caused the failures in the two
ASan test cases).
This patch was tested quite extensivelly both with sanitizer runtimes and
general code.
Differential revision: https://reviews.llvm.org/D93327
If a function happens to:
- call setjmp
- do a 16-byte stack allocation
- call a function that sets up a stack frame and longjmp's back
The stack pointer that is restores by setjmp will no longer point to a valid
back chain. According to the ABI, stack accesses in such a function are to be
frame pointer based - so it is an error (quite obviously) to restore the stack
from the back chain.
We already restore the stack from the frame pointer when there are calls to
fast_cc functions. We just need to also do that when there are calls to setjmp.
This patch simply does that.
This was pointed out by the Julia team.
Differential revision: https://reviews.llvm.org/D92906
During reviewing https://reviews.llvm.org/D84419, @efriedma mentioned the gap between realigned stack pointer and origin stack pointer should be probed too whatever the alignment is. This patch fixes the issue for PPC64.
Reviewed By: jsji
Differential Revision: https://reviews.llvm.org/D88078
This patch is the initial patch for support of the AIX extended vector ABI. The extended ABI treats vector registers V20-V31 as non-volatile and we add them as callee saved registers in this patch.
Reviewed By: sfertile
Differential Revision: https://reviews.llvm.org/D88676
After removal of Darwin as a PowerPC subtarget, the VRSAVE
save/restore/spill/update code is no longer needed by any supported
subtarget, so remove it while keeping support for vrsave and related instruction
aliases for inline asm. I've pre-commited tests to document the existing vrsave
handling in relation to @llvm.eh.unwind.init and inline asm usage, as
well as a test which shows a beahviour change on AIX related to
returning vector type as we were wrongly emiting VRSAVE_UPDATE on AIX.
General purpose registers 30 and 31 are handled differently when they are
reserved as the base-pointer and frame-pointer respectively. This fixes the
offset of their fixed-stack objects when there are fpr calle-saved registers.
Differential Revision: https://reviews.llvm.org/D85850
Current powerpc backend generates wrong code sequence if stack pointer
has to realign if -fstack-clash-protection enabled. When probing in
prologue, backend should generate a subtraction instruction rather
than a `stux` instruction to realign the stack pointer.
This patch is part of fix of
https://bugs.llvm.org/show_bug.cgi?id=46759.
Differential Revision: https://reviews.llvm.org/D84218
This patch is part of supporting `-fstack-clash-protection`. Implemented
probing when emitting prologue.
Differential Revision: https://reviews.llvm.org/D81460
Tail Calls were initially disabled for PC Relative code because it was not safe
to make certain assumptions about the tail calls (namely that all compiled
functions no longer used the TOC pointer in R2). However, once all of the
TOC pointer references have been removed it is safe to tail call everything
that was tail called prior to the PC relative additions as well as a number of
new cases.
For example, it is now possible to tail call indirect functions as there is no
need to save and restore the TOC pointer for indirect functions if the caller
is marked as may clobber R2 (st_other=1). For the same reason it is now also
possible to tail call functions that are external.
Differential Revision: https://reviews.llvm.org/D77788
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
Extends the existing support for spilling and restoring the condition
register to the linkage area for 32-bit targets, and enables for AIX.
Differential Revision: https://reviews.llvm.org/D74349
Remove some cumbersome Darwin specific logic for updating the frame
offsets of the condition-register spill slots. The containing function has an
early return if the subtarget is not ELF based which makes the Darwin logic
dead.
Create preprocessor defines for callee saved floating-point register spill
slots, vector register spill slots, and both 32-bit and 64-bit general
purpose register spill slots. This is an NFC refactor to prepare for
adding ABI compliant callee saves and restores for AIX.
Skip the loop over the CalleSavedInfos in 'restoreCalleeSavedRegisters' when
the register is a CR field and we are not targeting 32-bit ELF. This is safe
because:
1) The helper function 'restoreCRs' returns if the target is not 32-bit ELF,
making all the code in the loop related to CR fields dead for every other
subtarget. This code is only called on ELF right now, but the patch
to extend it for AIX also needs to skip 'restoreCRs'.
2) The loop will not otherwise modify the iterator, so the iterator
manipulations at the bottom of the loop end up setting 'I' to its
current value.
This simplifciation allows us to remove one argument from 'restoreCRs'.
Also add a helper function to determine if a register is one of the
callee saved condition register fields.
This patch:
- enable frame pointer for AIX;
- update some of red zone comments;
- add/update testcases;
Differential Revision: https://reviews.llvm.org/D72454
On little endian targets prior to Power9, we spill vector registers using a
swapping store (i.e. stdxvd2x saves the vector with the two doublewords in
big endian order regardless of endianness). This is generally not a problem
since we restore them using the corresponding swapping load (lxvd2x). However
if the restore is done by the unwinder, the vector register contains data in
the incorrect order.
This patch fixes that by using Altivec loads/stores for vector saves and
restores in PEI (which keep the order correct) under those specific conditions:
- EH aware function
- Subtarget requires swaps for VSX memops (Little Endian prior to Power9)
Differential revision: https://reviews.llvm.org/D73692
hasReservedSpillSlot returns a dummy frame index of '0' on PPC64 for the
non-volatile condition registers, which leads to the CalleSavedInfo
either referencing an unrelated stack object, or an invalid object if
there are no stack objects. The latter case causes the mir-printer to
crash due to assertions that checks if the frame index referenced by a
CalleeSavedInfo is valid.
To fix the problem create an immutable FixedStack object at the correct offset
in the linkage area of the previous stack frame (ie SP + positive offset).
Differential Revision: https://reviews.llvm.org/D73709
Extends the desciptor-based indirect call support for 32-bit codegen,
and enables indirect calls for AIX.
In-depth Description:
In a function descriptor based ABI, a function pointer points at a
descriptor structure as opposed to the function's entry point. The
descriptor takes the form of 3 pointers: 1 for the function's entry
point, 1 for the TOC anchor of the module containing the function
definition, and 1 for the environment pointer:
struct FunctionDescriptor {
void *EntryPoint;
void *TOCAnchor;
void *EnvironmentPointer;
};
An indirect call has several steps of loading the the information from
the descriptor into the proper registers for setting up the call. Namely
it has to:
1) Save the caller's TOC pointer into the TOC save slot in the linkage
area, and then load the callee's TOC pointer into the TOC register
(GPR 2 on AIX).
2) Load the function descriptor's entry point into the count register.
3) Load the environment pointer into the environment pointer register
(GPR 11 on AIX).
4) Perform the call by branching on count register.
5) Restore the caller's TOC pointer after returning from the indirect call.
A couple important caveats to the above:
- There is no way to directly load a value from memory into the count register.
Instead we populate the count register by loading the entry point address into
a gpr and then moving the gpr to the count register.
- The TOC restore has to come immediately after the branch on count register
instruction (i.e., the 1st instruction executed after we return from the
call). This is an implementation limitation. We could, in theory, schedule
the restore elsewhere as long as no uses of the TOC pointer fall in between
the call and the restore; however, to keep it simple, we insert a pseudo
instruction that represents both the indirect branch instruction and the
load instruction that restores the caller's TOC from the linkage area. As
they flow through the compiler as a single pseudo instruction, nothing can be
inserted between them and the caller's TOC is then valid at any use.
Differtential Revision: https://reviews.llvm.org/D70724
This adds a flag to LLVM and clang to always generate a .debug_frame
section, even if other debug information is not being generated. In
situations where .eh_frame would normally be emitted, both .debug_frame
and .eh_frame will be used.
Differential Revision: https://reviews.llvm.org/D67216
Kai Luo