Commit Graph

86 Commits

Author SHA1 Message Date
Hal Finkel
f8d179ba76 [PowerPC] Add support for the QPX vector instruction set
This adds support for the QPX vector instruction set, which is used by the
enhanced A2 cores on the IBM BG/Q supercomputers. QPX vectors are 256 bytes
wide, holding 4 double-precision floating-point values. Boolean values, modeled
here as <4 x i1> are actually also represented as floating-point values
(essentially  { -1, 1 } for { false, true }). QPX shares many features with
Altivec and VSX, but is distinct from both of them. One major difference is
that, instead of adding completely-separate vector registers, QPX vector
registers are extensions of the scalar floating-point registers (lane 0 is the
corresponding scalar floating-point value). The operations supported on QPX
vectors mirrors that supported on the scalar floating-point values (with some
additional ones for permutations and logical/comparison operations).

I've been maintaining this support out-of-tree, as part of the bgclang project,
for several years. This is not the entire bgclang patch set, but is most of the
subset that can be cleanly integrated into LLVM proper at this time. Adding
this to the LLVM backend is part of my efforts to rebase bgclang to the current
LLVM trunk, but is independently useful (especially for codes that use LLVM as
a JIT in library form).

The assembler/disassembler test coverage is complete. The CodeGen test coverage
is not, but I've included some tests, and more will be added as follow-up work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230413 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-25 01:06:45 +00:00
Chandler Carruth
96db150cec Remove a variable only used in an assert and sink its initializer into
the assert. Fixes -Wunused-variable on non-asserts builds.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229250 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 09:14:44 +00:00
Duncan P. N. Exon Smith
4eba62d6c2 PowerPC: Canonicalize access to function attributes, NFC
Canonicalize access to function attributes to use the simpler API.

getAttributes().getAttribute(AttributeSet::FunctionIndex, Kind)
  => getFnAttribute(Kind)

getAttributes().hasAttribute(AttributeSet::FunctionIndex, Kind)
  => hasFnAttribute(Kind)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229224 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-14 02:54:07 +00:00
Eric Christopher
40ccb77781 The base pointer save offset can be computed at initialization time,
do so and fix up the calls.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229169 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 22:48:53 +00:00
Eric Christopher
4015892a84 PPC LinkageSize can be computed at initialization time, do so.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229163 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 22:22:57 +00:00
Eric Christopher
2b4e1b9abf PPCFrameLowering's FramePointerOffset can be computed at initialization
time. Do so.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228998 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 00:39:38 +00:00
Eric Christopher
82eeeb5b94 The TOC save offset can be computed at compile time, do so and
propagate changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228997 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 00:39:36 +00:00
Eric Christopher
b947233818 The return save offset can be computed at initialization time - do
so and save the value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228996 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 00:39:27 +00:00
Bill Schmidt
49b3971b70 [PowerPC] Fix reverted patch r227976 to avoid register assignment issues
See full discussion in http://reviews.llvm.org/D7491.

We now hide the add-immediate and call instructions together in a
separate pseudo-op, which is tagged to define GPR3 and clobber the
call-killed registers.  The PPCTLSDynamicCall pass prior to RA now
expands this op into the two separate addi and call ops, with explicit
definitions of GPR3 on both instructions, and explicit clobbers on the
call instruction.  The pass is now marked as requiring and preserving
the LiveIntervals and SlotIndexes analyses, and fixes these up after
the replacement sequences are introduced.

Self-hosting has been verified on LE P8 and BE P7 with various
optimization levels, etc.  It has also been verified with the
--no-tls-optimize flag workaround removed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228725 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-10 19:09:05 +00:00
Hal Finkel
9168f717c9 Revert "r227976 - [PowerPC] Yet another approach to __tls_get_addr" and related fixups
Unfortunately, even with the workaround of disabling the linker TLS
optimizations in Clang restored (which has already been done), this still
breaks self-hosting on my P7 machine (-O3 -DNDEBUG -mcpu=native).

Bill is currently working on an alternate implementation to address the TLS
issue in a way that also fully elides the linker bug (which, unfortunately,
this approach did not fully), so I'm reverting this now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228460 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-06 23:07:40 +00:00
Bill Schmidt
1123a81009 [PowerPC] Yet another approach to __tls_get_addr
This patch is a third attempt to properly handle the local-dynamic and
global-dynamic TLS models.

In my original implementation, calls to __tls_get_addr were hidden
from view until the asm-printer phase, at which point the underlying
branch-and-link instruction was created with proper relocations.  This
mostly worked well, but I used some repellent techniques to ensure
that the TLS_GET_ADDR nodes at the SD and MI levels correctly received
input from GPR3 and produced output into GPR3.  This proved to work
badly in the presence of multiple TLS variable accesses, with the
copies to and from GPR3 being scheduled incorrectly and generally
creating havoc.

In r221703, I addressed that problem by representing the calls to
__tls_get_addr as true calls during instruction lowering.  This had
the advantage of removing all of the bad hacks and relying on the
existing call machinery to properly glue the copies in place. It
looked like this was going to be the right way to go.

However, as a side effect of the recent discovery of problems with
linker optimizations for TLS, we discovered cases of suboptimal code
generation with this strategy.  The problem comes when tls_get_addr is
called for the same address, and there is a resulting CSE
opportunity.  It turns out that in such cases MachineCSE will common
the addis/addi instructions that set up the input value to
tls_get_addr, but will not common the calls themselves.  MachineCSE
does not have any machinery to common idempotent calls.  This is
perfectly sensible, since presumably this would be done at the IR
level, and introducing calls in the back end isn't commonplace.  In
any case, we end up with two calls to __tls_get_addr when one would
suffice, and that isn't good.

I presumed that the original design would have allowed commoning of
the machine-specific nodes that hid the __tls_get_addr calls, so as
suggested by Ulrich Weigand, I went back to that design and cleaned it
up so that the copies were properly held together by glue
nodes.  However, it turned out that this didn't work either...the
presence of copies to physical registers kept the machine-specific
nodes from being commoned also.

All of which leads to the design presented here.  This is a return to
the original design, except that no attempt is made to introduce
copies to and from GPR3 during instruction lowering.  Virtual registers
are used until prior to register allocation.  At that point, a special
pass is run that identifies the machine-specific nodes that hide the
tls_get_addr calls and introduces the copies to and from GPR3 around
them.  The register allocator then coalesces these copies away.  With
this design, MachineCSE succeeds in commoning tls_get_addr calls where
possible, and we get nice optimal code generation (better than GCC at
the moment, which does not common these calls).

One additional problem must be dealt with:  After introducing the
mentions of the physical register GPR3, the aggressive anti-dependence
breaker sees opportunities to improve scheduling by selecting a
different register instead.  Flags must be used on the instruction
descriptions to tell the anti-dependence breaker to keep its hands in
its pockets.

One thing missing from the original design was recording a definition
of the link register on the GET_TLS_ADDR nodes.  Doing this was found
to be insufficient to force a stack frame to be created, which led to
looping behavior because two different LR values were stored at the
same address.  This appears to have been an oversight in
PPCFrameLowering::determineFrameLayout(), which is repaired here.

Because MustSaveLR() returns true for calls to builtin_return_address,
this changed the expected behavior of
test/CodeGen/PowerPC/retaddr2.ll, which now stacks a frame but
formerly did not.  I've fixed the test case to reflect this.

There are existing TLS tests to catch regressions; the checks in
test/CodeGen/PowerPC/tls-store2.ll proved to be too restrictive in the
face of instruction scheduling with these changes, so I fixed that
up.

I've added a new test case based on the PrettyStackTrace module that
demonstrated the original problem. This checks that we get correct
code generation and that CSE of the calls to __get_tls_addr has taken
place.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227976 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-03 16:16:01 +00:00
Eric Christopher
5882e66f5b Use the cached subtargets and remove calls to getSubtarget/getSubtargetImpl
without a Function argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227622 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-30 22:02:31 +00:00
Eric Christopher
dd5e9f624b Use the cached subtarget in PPCFrameLowering.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227548 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-30 02:11:26 +00:00
Hal Finkel
ade705c6e5 Revert "r225811 - Revert "r225808 - [PowerPC] Add StackMap/PatchPoint support""
This re-applies r225808, fixed to avoid problems with SDAG dependencies along
with the preceding fix to ScheduleDAGSDNodes::RegDefIter::InitNodeNumDefs.
These problems caused the original regression tests to assert/segfault on many
(but not all) systems.

Original commit message:

This commit does two things:

 1. Refactors PPCFastISel to use more of the common infrastructure for call
    lowering (this lets us take advantage of this common code for lowering some
    common intrinsics, stackmap/patchpoint among them).

 2. Adds support for stackmap/patchpoint lowering. For the most part, this is
    very similar to the support in the AArch64 target, with the obvious differences
    (different registers, NOP instructions, etc.). The test cases are adapted
    from the AArch64 test cases.

One difference of note is that the patchpoint call sequence takes 24 bytes, so
you can't use less than that (on AArch64 you can go down to 16). Also, as noted
in the docs, we take the patchpoint address to be the actual code address
(assuming the call is local in the TOC-sharing sense), which should yield
higher performance than generating the full cross-DSO indirect-call sequence
and is likely just as useful for JITed code (if not, we'll change it).

StackMaps and Patchpoints are still marked as experimental, and so this support
is doubly experimental. So go ahead and experiment!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225909 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-14 01:07:51 +00:00
Hal Finkel
ea55eceaed Revert "r225808 - [PowerPC] Add StackMap/PatchPoint support"
Reverting this while I investiage buildbot failures (segfaulting in
GetCostForDef at ScheduleDAGRRList.cpp:314).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225811 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 18:25:05 +00:00
Hal Finkel
232f393466 [PowerPC] Add StackMap/PatchPoint support
This commit does two things:

 1. Refactors PPCFastISel to use more of the common infrastructure for call
    lowering (this lets us take advantage of this common code for lowering some
    common intrinsics, stackmap/patchpoint among them).

 2. Adds support for stackmap/patchpoint lowering. For the most part, this is
    very similar to the support in the AArch64 target, with the obvious differences
    (different registers, NOP instructions, etc.). The test cases are adapted
    from the AArch64 test cases.

One difference of note is that the patchpoint call sequence takes 24 bytes, so
you can't use less than that (on AArch64 you can go down to 16). Also, as noted
in the docs, we take the patchpoint address to be the actual code address
(assuming the call is local in the TOC-sharing sense), which should yield
higher performance than generating the full cross-DSO indirect-call sequence
and is likely just as useful for JITed code (if not, we'll change it).

StackMaps and Patchpoints are still marked as experimental, and so this support
is doubly experimental. So go ahead and experiment!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225808 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 17:48:12 +00:00
Hal Finkel
a82e676bac [PowerPC] Split the blr definition into BLR and BLR8
We really need a separate 64-bit version of this instruction so that it can be
marked as clobbering LR8 (instead of just LR). No change in functionality
(although the verifier might be slightly happier), however, it is required for
stackmap/patchpoint support. Thus, this will be covered by stackmap test cases
once those are added.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225804 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 17:47:54 +00:00
Justin Hibbits
1c6936f6d7 Fully fix Bug #22115.
Summary:
In the previous commit, the register was saved, but space was not allocated.
This resulted in the parameter save area potentially clobbering r30, leading to
nasty results.

Test Plan: Tests updated

Reviewers: hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6906

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225573 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-10 01:57:21 +00:00
Justin Hibbits
77e85a150c Add saving and restoring of r30 to the prologue and epilogue, respectively
Summary: The PIC additions didn't update the prologue and epilogue code to save and restore r30 (PIC base register).  This does that.

Test Plan: Tests updated.

Reviewers: hfinkel

Reviewed By: hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6876

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225450 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-08 15:47:19 +00:00
Jay Foad
8b9cea42db [PowerPC] Fix unwind info with dynamic stack realignment
Summary:
PowerPC DWARF unwind info defined CFA as SP + offset even in a function
where the stack had been dynamically realigned. This clearly doesn't
work because the offset from SP to CFA is not a constant. Fix it by
defining CFA as BP instead.

This was causing the AddressSanitizer null_deref test to fail 50% of
the time, depending on whether SP happened to be 32-byte aligned on
entry to a particular function or not.

Reviewers: willschm, uweigand, hfinkel

Reviewed By: hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6410

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222996 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-01 09:42:32 +00:00
Eric Christopher
6035518e3b Have MachineFunction cache a pointer to the subtarget to make lookups
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.

Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214838 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-05 02:39:49 +00:00
Eric Christopher
9f85dccfc6 Remove the TargetMachine forwards for TargetSubtargetInfo based
information and update all callers. No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214781 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-04 21:25:23 +00:00
Ulrich Weigand
970c019d02 [PowerPC] ELFv2 explicit CFI for CR fields
This is a minor improvement in the ELFv2 ABI.   In ELFv1, DWARF CFI
would represent a saved CR word (holding CR fields CR2, CR3, and CR4)
using just a single CFI record refering to CR2.   In ELFv2 instead,
each of the CR fields is represented by its own CFI record.  The
advantage is that the compiler can now chose to save just a single
(or two) CR fields instead of all of them, if those are the only ones
that actually need saving.  That can lead to more efficient code using
mf(o)crf instead of the (slow) mfcr instruction.

Note that this patch does not (yet) implement this more efficient
code generation, but it does implement the part that is required to
be ABI compliant: creating multiple CFI records if multiple CR fields
are saved.

Reviewed by Hal Finkel.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213492 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-21 00:03:18 +00:00
Ulrich Weigand
7fc5011e8d [PowerPC] ELFv2 stack space reduction
The ELFv2 ABI reduces the amount of stack required to implement an
ABI-compliant function call in two ways:
* the "linkage area" is reduced from 48 bytes to 32 bytes by
  eliminating two unused doublewords
* the 64-byte "parameter save area" is now optional and need not be
  present in certain cases (it remains mandatory in functions with
  variable arguments, and functions that have any parameter that is
  passed on the stack)

The following patch implements this required changes:
- reducing the linkage area, and associated relocation of the TOC save
  slot, in getLinkageSize / getTOCSaveOffset (this requires updating all
  callers of these routines to pass in the isELFv2ABI flag).
- (partially) handling the case where the parameter save are is optional

This latter part requires some extra explanation:  Currently, we still
always allocate the parameter save area when *calling* a function.
That is certainly always compliant with the ABI, but may cause code to
allocate stack unnecessarily.  This can be addressed by a follow-on
optimization patch.

On the *callee* side, in LowerFormalArguments, we *must* track
correctly whether the ABI guarantees that the caller has allocated
the parameter save area for our use, and the patch does so. However,
there is one complication: the code that handles incoming "byval"
arguments will currently *always* write to the parameter save area,
because it has to force incoming register arguments to the stack since
it must return an *address* to implement the byval semantics.

To fix this, the patch changes the LowerFormalArguments code to write
arguments to a freshly allocated stack slot on the function's own stack
frame instead of the argument save area in those cases where that area
is not present.

Reviewed by Hal Finkel.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213490 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-20 23:43:15 +00:00
Hal Finkel
d644d17dd4 [PowerPC] 32-bit ELF PIC support
This adds initial support for PPC32 ELF PIC (Position Independent Code; the
-fPIC variety), thus rectifying a long-standing deficiency in the PowerPC
backend.

Patch by Justin Hibbits!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213427 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-18 23:29:49 +00:00
Ulrich Weigand
b548b6bfc3 [PowerPC] Refactor getMinCallFrameSize / getMinCallArgumentsSize
As of r211495, the only remaining users of getMinCallFrameSize are in
core ABI code (LowerFormalParameter / LowerCall).  This is actually a
good thing, since the details of the parameter save area are ABI specific.

With the new ELFv2 ABI in particular, the rules defining the size of the
save area will become significantly more complex, so it wouldn't make
sense to implement those outside ABI code that has all required
information.

In preparation, this patch eliminates the getMinCallFrameSize (and
associated getMinCallArgumentsSize) routines, and inlines them into all
callers.  Note that since nearly all call arguments are constant, this
allows simplifying the inlined copies to a single line everywhere.

No change in generate code expected.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211497 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-23 14:15:53 +00:00
Ulrich Weigand
9a154bfe94 [PowerPC] Allow stack frames without parameter save area
The PPCFrameLowering::determineFrameLayout routine currently ensures
that every function that allocates a stack frame provides space for the
parameter save area (via PPCFrameLowering::getMinCallFrameSize).

This is actually not necessary.  There may be functions that never call
another routine but still allocate a frame; those do not require the
parameter save area.  In the future, with the ELFv2 ABI, even some
routines that do call other functions do not need to allocate the
parameter save area.

While it is not a bug to allocate the parameter area when it is not
needed, it is better to avoid it to save stack space.

Note that when any particular function call requires the parameter save
area, this space will already have been included by ABI code in the size
the CALLSEQ_START insn is annotated with, and therefore included in the
size returned by MFI->getMaxCallFrameSize().

This means that determineFrameLayout simply does not need to care about
the parameter save area.  (It still needs to ensure that every frame
provides the linkage area.)  This is implemented by this patch.

Note that this exposed a bug in the new fast-isel code where the parameter
area was *not* included in the CALLSEQ_START size; this is also fixed.

A couple of test cases needed to be adapted for the new (smaller) stack
frame size those tests now see.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211495 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-23 13:47:52 +00:00
Eric Christopher
054a74452c Move PPCFrameLowering into PPCSubtarget from PPCTargetMachine. Use
the initializeSubtargetDependencies code to obtain an initialized
subtarget and migrate a couple of subtarget using functions to the
.cpp file to avoid circular includes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210822 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-12 20:54:11 +00:00
Eric Christopher
aa475b48cc None of these targets actually define their own CFI_INSTRUCTION
opcode so there's no reason to use the target namespace for it
rather than TargetOpcode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207475 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-29 00:16:46 +00:00
Eric Christopher
3756feaadc 80-column, tab characters, comment fixups.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207473 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-29 00:16:40 +00:00
Rafael Espindola
7d7d99622f Replace PROLOG_LABEL with a new CFI_INSTRUCTION.
The old system was fairly convoluted:
* A temporary label was created.
* A single PROLOG_LABEL was created with it.
* A few MCCFIInstructions were created with the same label.

The semantics were that the cfi instructions were mapped to the PROLOG_LABEL
via the temporary label. The output position was that of the PROLOG_LABEL.
The temporary label itself was used only for doing the mapping.

The new CFI_INSTRUCTION has a 1:1 mapping to MCCFIInstructions and points to
one by holding an index into the CFI instructions of this function.

I did consider removing MMI.getFrameInstructions completelly and having
CFI_INSTRUCTION own a MCCFIInstruction, but MCCFIInstructions have non
trivial constructors and destructors and are somewhat big, so the this setup
is probably better.

The net result is that we don't create temporary labels that are never used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203204 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-07 06:08:31 +00:00
Bill Schmidt
6af35e9576 [PowerPC] More refactoring prior to real PPC emitPrologue/Epilogue changes.
(Patch committed on behalf of Mark Minich, whose log entry follows.)

This is a continuation of the refactorings performed in svn rev 188573
(see that rev's comments for more detail).

This is my stage 2 refactoring: I combined the emitPrologue() &
emitEpilogue() PPC32 & PPC64 code into a single flow, simplifying a
lot of the code since in essence the PPC32 & PPC64 code generation
logic is the same, only the instruction forms are different (in most
cases). This simplification is necessary because my functional changes
(yet to come) add significant complexity, and without the
simplification of my stage 2 refactoring, the overall complexity of
both emitPrologue() & emitEpilogue() would have become almost
intractable for most mortal programmers (like me).

This submission was intended to be a pure refactoring (no functional
changes whatsoever). However, in the process of combining the PPC32 &
PPC64 flows, I spotted a difference that I believe is a bug (see svn
rev 186478 line 863, or svn rev 188573 line 888): This line appears to
be restoring the BP with the original FP content, not the original BP
content. When I merged the 32-bit and 64-bit code, I used the
corresponding code from the 64-bit flow, which I believe uses the
correct offset (BPOffset) for this operation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188741 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-20 03:12:23 +00:00
Bill Schmidt
9bb6c81683 [PowerPC] Preparatory refactoring for making prologue and epilogue
safe on PPC32 SVR4 ABI

[Patch and following text by Mark Minich; committing on his behalf.]

There are FIXME's in PowerPC/PPCFrameLowering.cpp, method
PPCFrameLowering::emitPrologue() related to "negative offsets of R1"
on PPC32 SVR4. They're true, but the real issue is that on PPC32 SVR4
(and any ABI without a Red Zone), no spills may be made until after
the stackframe is claimed, which also includes the LR spill which is
at a positive offset. The same problem exists in emitEpilogue(),
though there's no FIXME for it. I intend to fix this issue, making
LLVM-compiled code finally safe for use on SVR4/EABI/e500 32-bit
platforms (including in particular, OS-free embedded systems & kernel
code, where interrupts may share the same stack as user code).

In preparation for making these changes, to make the diffs for the
functional changes less cluttered, I am providing the non-functional
refactorings in two stages:

Stage 1 does some minor fluffy refactorings to pull multiple method
calls up into a single bool, creating named bools for repeated uses of
obscure logic, moving some code up earlier because either stage 2 or
my final version will require it earlier, and rewording/adding some
comments. My stage 1 changes can be characterized as primarily fluffy
cleanup, the purpose of which may be unclear until the stage 2 or
final changes are made.

My stage 2 refactorings combine the separate PPC32 & PPC64 logic,
which is currently performed by largely duplicate code, into a single
flow, with the differences handled by a group of constants initialized
early in the methods.

This submission is for my stage 1 changes. There should be no
functional changes whatsoever; this is a pure refactoring.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188573 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-16 20:05:04 +00:00
Hal Finkel
aad2a72c28 PPC: Support dynamic allocas with large alignment
Support for dynamic stack alignments in the PPC backend has been unfinished, in
part because it depends on dynamic stack realignment (which I only just
recently implemented fully). Now we can also support dynamic allocas with
higher than the default target stack alignment (16 bytes).

In order to round-up the requested size to the maximum requested alignment, we
need an additional register to hold the rounded-up size. We're already using one
scavenged register to hold the previous stack-pointer value (which needs to be
stored with the signal-safe stdux update), and so when we have dynamic allocas
and a large alignment, we allocate two emergency spill slots for the scavenger.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186562 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-18 04:28:21 +00:00
Hal Finkel
0541722de4 PPC: Add base-pointer support to builtin setjmp/longjmp
First, this changes the base-pointer implementation to remove an unnecessary
complication (and one that is incompatible with how builtin SjLj is
implemented): instead of using r31 as the base pointer when it is not needed as
a frame pointer, now the base pointer will always be r30 when needed.

Second, we introduce another pseudo register, BP, which is used just like the FP
pseudo register to refer to the base register before we know for certain what
register it will be.

Third, we now save BP into the jmp_buf, and restore r30 from that slot in
longjmp.  If the function that called setjmp did not use a base pointer, then
r30 will be overwritten by the setjmp-calling-function's restore code. FP
restoration (which is restored into r31) works the same way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186545 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 23:50:51 +00:00
Hal Finkel
fe47bf8fa0 PPC: Implement base pointer and stack realignment
This builds on some frame-lowering code that has existed since 2005 (r24224)
but was disabled in 2008 (r48188) because it needed base pointer support to
function correctly. This implementation follows the strategy suggested by Dale
Johannesen in r48188 where the following comment was added:

  This does not currently work, because the delta between old and new stack
  pointers is added to offsets that reference incoming parameters after the
  prolog is generated, and the code that does that doesn't handle a variable
  delta.  You don't want to do that anyway; a better approach is to reserve
  another register that retains to the incoming stack pointer, and reference
  parameters relative to that.

And now we do exactly that. If we don't need a frame pointer, then we use r31
as a base pointer. If we do need a frame pointer, then we use r30 as a base
pointer. The base pointer retains the value of the stack pointer before it was
decremented in the prologue. We then use the base pointer to resolve all
negative frame indicies. The basic scheme follows that for base pointers in the
X86 backend.

We use a base pointer when we need to dynamically realign the incoming stack
pointer. This currently applies only to static objects (dynamic allocas with
large alignments, and base-pointer support in SjLj lowering will come in future
commits).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186478 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 00:45:52 +00:00
Craig Topper
a0ec3f9b7b Use SmallVectorImpl& instead of SmallVector to avoid repeating small vector size.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186274 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-14 04:42:23 +00:00
Ulrich Weigand
33efedc048 [PowerPC] Use mtocrf when available
Just as with mfocrf, it is also preferable to use mtocrf instead of
mtcrf when only a single CR register is to be written.

Current code however always emits mtcrf.  This probably does not matter
when using an external assembler, since the GNU assembler will in fact
automatically replace mtcrf with mtocrf when possible.  It does create
inefficient code with the integrated assembler, however.

To fix this, this patch adds MTOCRF/MTOCRF8 instruction patterns and
uses those instead of MTCRF/MTCRF8 everything.  Just as done in the
MFOCRF patch committed as 185556, these patterns will be converted
back to MTCRF if MTOCRF is not available on the machine.

As a side effect, this allows to modify the MTCRF pattern to accept
the full range of mask operands for the benefit of the asm parser.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185561 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-03 17:59:07 +00:00
Hal Finkel
6a636a813f PPC: Ignore spill/restore requests for VRSAVE (except on Darwin)
This fixes PR16418, which reports that a function calling
__builtin_unwind_init() asserts. The cause is that this generates a
spill/restore for VRSAVE, and we support that only on Darwin (because VRSAVE is
only really used on Darwin).

The test case checks only that we don't crash. We can add correctness checks
once someone verifies what behavior the function is supposed to have.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185235 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-28 22:29:56 +00:00
Bill Wendling
99cb622041 Use pointers to the MCAsmInfo and MCRegInfo.
Someone may want to do something crazy, like replace these objects if they
change or something.

No functionality change intended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184175 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-18 07:20:20 +00:00
Rafael Espindola
6b67ffd68b Remove addFrameMove.
Now that we have good testing, remove addFrameMove and create cfi
instructions directly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182052 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-16 21:02:15 +00:00
Ulrich Weigand
347a5079e1 [PowerPC] Use true offset value in "memrix" machine operands
This is the second part of the change to always return "true"
offset values from getPreIndexedAddressParts, tackling the
case of "memrix" type operands.

This is about instructions like LD/STD that only have a 14-bit
field to encode immediate offsets, which are implicitly extended
by two zero bits by the machine, so that in effect we can access
16-bit offsets as long as they are a multiple of 4.

The PowerPC back end currently handles such instructions by
carrying the 14-bit value (as it will get encoded into the
actual machine instructions) in the machine operand fields
for such instructions.  This means that those values are
in fact not the true offset, but rather the offset divided
by 4 (and then truncated to an unsigned 14-bit value).

Like in the case fixed in r182012, this makes common code
operations on such offset values not work as expected.
Furthermore, there doesn't really appear to be any strong
reason why we should encode machine operands this way.

This patch therefore changes the encoding of "memrix" type
machine operands to simply contain the "true" offset value
as a signed immediate value, while enforcing the rules that
it must fit in a 16-bit signed value and must also be a
multiple of 4.

This change must be made simultaneously in all places that
access machine operands of this type.  However, just about
all those changes make the code simpler; in many cases we
can now just share the same code for memri and memrix
operands.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182032 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-16 17:58:02 +00:00
Rafael Espindola
ec7f4231cb Removed dead code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181975 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-16 03:34:58 +00:00
Bill Schmidt
ded53bf4dd PPC32: Fix stack collision between FP and CR save areas.
The changes to CR spill handling missed a case for 32-bit PowerPC.
The code in PPCFrameLowering::processFunctionBeforeFrameFinalized()
checks whether CR spill has occurred using a flag in the function
info.  This flag is only set by storeRegToStackSlot and
loadRegFromStackSlot.  spillCalleeSavedRegisters does not call
storeRegToStackSlot, but instead produces MI directly.  Thus we don't
see the CR is spilled when assigning frame offsets, and the CR spill
ends up colliding with some other location (generally the FP slot).

This patch sets the flag in spillCalleeSavedRegisters for PPC32 so
that the CR spill is properly detected and gets its own slot in the
stack frame.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181800 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-14 16:08:32 +00:00
Rafael Espindola
d84ccfaf50 Change getFrameMoves to return a const reference.
To add a frame now there is a dedicated addFrameMove which also takes
care of constructing the move itself.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181657 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-11 02:38:11 +00:00
Hal Finkel
fb6fe0aea2 Fix PPC64 CR spill location for callee-saved registers
This fixes an ABI bug for non-Darwin PPC64. For the callee-saved condition
registers, the spill location is specified relative to the stack pointer (SP +
8). However, this is not relative to the SP after the new stack frame is
established, but instead relative to the caller's stack pointer (it is stored
into the linkage area of the parent's stack frame).

So, like with the link register, we don't directly spill the CRs with other
callee-saved registers, but just mark them to be spilled during prologue
generation.

In practice, this reverts r179457 for PPC64 (but leaves it in place for PPC32).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179500 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-15 02:07:05 +00:00
Hal Finkel
63496f66c5 Mark all PPC CR registers to be spilled as live-in and tag MFCR appropriately
Leaving MFCR has having unmodeled side effects is not enough to prevent
unwanted instruction reordering post-RA. We could probably apply a stronger
barrier attribute, but there is a better way: Add all (not just the first) CR
to be spilled as live-in to the entry block, and add all CRs to the MFCR
instruction as implicitly killed.

Unfortunately, I don't have a small test case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179465 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-13 23:06:15 +00:00
Hal Finkel
b99c995825 Spill and restore PPC CR registers using the FP when we have one
For functions that need to spill CRs, and have dynamic stack allocations, the
value of the SP during the restore is not what it was during the save, and so
we need to use the FP in these cases (as for all of the other spills and
restores, but the CR restore has a special code path because its reserved slot,
like the link register, is specified directly relative to the adjusted SP).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179457 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-13 08:09:20 +00:00
Hal Finkel
d957f957ee Cleanup PPC CR-spill kill flags and 32- vs. 64-bit instructions
There were a few places where kill flags were not being set correctly, and
where 32-bit instruction variants were being used with 64-bit registers. After
r178180, this code was being triggered causing llc to assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178220 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-28 03:38:16 +00:00
Hal Finkel
aa6047d23d PPC: Use HWEncoding and TRI->getEncodingValue
As pointed out by Jakob, we don't need to maintain a separate
register-numbering table. Instead we should let TableGen generate the table for
us from the information (already present) in PPCRegisterInfo.td.
TRI->getEncodingValue is now used to access register-encoding values.

No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178067 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-26 20:08:20 +00:00