Added some debugging output to pre-alloc splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84681 91177308-0d34-0410-b5e6-96231b3b80d8

add a real testcase for PR4313

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84676 91177308-0d34-0410-b5e6-96231b3b80d8

add a test similar to that needed for PR4313, but that doesn't
fail without the patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84675 91177308-0d34-0410-b5e6-96231b3b80d8

the date on this testcase is wrong, it is unreduced, and it passes without the fix for PR4313.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84674 91177308-0d34-0410-b5e6-96231b3b80d8

Fix another place that calls Loop::contains a lot to construct a sorted
container of the blocks and do efficient lookups. This makes
isLoopSimplifyForm much faster on large loops, fixing a significant
compile-time issue in builds with assertions enabled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84673 91177308-0d34-0410-b5e6-96231b3b80d8

merge and filecheckize

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84672 91177308-0d34-0410-b5e6-96231b3b80d8

merge two tests and convert to filecheck.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84671 91177308-0d34-0410-b5e6-96231b3b80d8

Disable by default while debugging

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84669 91177308-0d34-0410-b5e6-96231b3b80d8

alternate fix for PR5258 which avoids worklist problems, with reduced testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84667 91177308-0d34-0410-b5e6-96231b3b80d8

add cmd line opt to disable frame index reuse for ARM and T2. debug aid.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84664 91177308-0d34-0410-b5e6-96231b3b80d8

Restore LoopUnswitch's block-oriented threshold. LoopUnswitch now checks both
the estimated code size and the number of blocks when deciding whether to
do a non-trivial unswitch. This protects it from some very undesirable
worst-case behavior on large numbers of loop-unswitchable conditions, such
as in the testcase in PR5259.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84661 91177308-0d34-0410-b5e6-96231b3b80d8

Checkpoint more aggressive anti-dependency breaking for post-ra scheduler.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84658 91177308-0d34-0410-b5e6-96231b3b80d8

Better handle instructions that re-def a scratch register

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84657 91177308-0d34-0410-b5e6-96231b3b80d8

Following r84485, add Defs = [EFLAGS] to the 32-bit lock instructions too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84652 91177308-0d34-0410-b5e6-96231b3b80d8

Move the Function*->allocated blocks map from the JITMemoryManager to the
JITEmitter.

I'm gradually making Functions auto-remove themselves from the JIT when they're
destroyed. In this case, the Function needs to be removed from the JITEmitter,
but the map recording which Functions need to be removed lived behind the
JITMemoryManager interface, which made things difficult.

This patch replaces the deallocateMemForFunction(Function*) method with a pair
of methods deallocateFunctionBody(void *) and deallocateExceptionTable(void *)
corresponding to the two startFoo/endFoo pairs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84651 91177308-0d34-0410-b5e6-96231b3b80d8

Register re-use for scavenged frame indices must check for re-deginition
of the register in the instruction which kills the scavenged value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84641 91177308-0d34-0410-b5e6-96231b3b80d8

Make TranslateX86CC return COND_INVALID instead of aborting when it
encounters an OEQ or UNE comparison, and update its callers to check
for this return status and recover. This fixes a problem resulting from
the LowerOperation hooks being called from LegalizeVectorOps, because
LegalizeVectorOps only lowers vectors, so OEQ and UNE comparisons may
still be at large. This fixes PR5092.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84640 91177308-0d34-0410-b5e6-96231b3b80d8

Fix PR5258, jump-threading creating invalid PHIs.
When an incoming value for a PHI is updated, we must also updated all other
incoming values for the same BB to match, otherwise we create invalid PHIs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84638 91177308-0d34-0410-b5e6-96231b3b80d8

Fix PR4313: IPSCCP was not setting the lattice value for the invoke instruction
when the invoke had multiple return values: it set the lattice value only on the
extractvalue.
This caused the invoke's lattice value to remain the default (undefined), and
later propagated to extractvalue's operand, which incorrectly introduces
undefined behavior.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84637 91177308-0d34-0410-b5e6-96231b3b80d8

Random #include pruning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84632 91177308-0d34-0410-b5e6-96231b3b80d8

This file is replaeced by PIC16Section.h.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84628 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Implement "config mode", use -config path/to/llvm-config

 - This runs the nightly test and does all the submission logic, but using the
   LLVM build specified by the llvm-config.

 - Useful for, among other things, testing NNT itself.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84620 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Remove unused BUILDTYPE argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84619 91177308-0d34-0410-b5e6-96231b3b80d8

implement some more easy hooks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84614 91177308-0d34-0410-b5e6-96231b3b80d8

Implement some hooks, make printOperand abort if unknown modifiers are
present.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84613 91177308-0d34-0410-b5e6-96231b3b80d8

t2MOVi32imm is currently always lowered by the Thumb2ITBlockPass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84611 91177308-0d34-0410-b5e6-96231b3b80d8

PowerPC ifdef'ing considered more complicated than one might like.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84603 91177308-0d34-0410-b5e6-96231b3b80d8

Wire up the ARM MCInst printer, for llvm-mc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84600 91177308-0d34-0410-b5e6-96231b3b80d8

Re-apply r84295, with fixes to how the loop "top" and "bottom" blocks are
tracked. Instead of trying to manually keep track of these locations
while doing complex modifications, just recompute them when they're needed.
This fixes a bug in which the TopMBB and BotMBB were not correctly updated,
leading to invalid transformations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84598 91177308-0d34-0410-b5e6-96231b3b80d8

Trim unnecessary includes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84597 91177308-0d34-0410-b5e6-96231b3b80d8

Add getTopBlock and getBottomBlock member functions to MachineLoopInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84596 91177308-0d34-0410-b5e6-96231b3b80d8

Correct test for PowerPC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84595 91177308-0d34-0410-b5e6-96231b3b80d8

Revert "Tweak top-level Makefile to facilitate Apple-style build.", this is
breaking Clang's Apple-style build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84592 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Remove duplicate verbose print.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84591 91177308-0d34-0410-b5e6-96231b3b80d8

Now that all ARM subtargets use frame index scavenging, the Thumb1 requires*
functions are not needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84587 91177308-0d34-0410-b5e6-96231b3b80d8

If the physical register being spilled does not have an interval, spill its sub-registers instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84586 91177308-0d34-0410-b5e6-96231b3b80d8

Enable post-pass frame index register scavenging for ARM and Thumb2

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84585 91177308-0d34-0410-b5e6-96231b3b80d8

lower ARM::MOVi32imm properly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84583 91177308-0d34-0410-b5e6-96231b3b80d8

add support for external symbols.  The mc instprinter  can now handle
reasonable code like Codegen/ARM/2009-02-27-SpillerBug.ll, producing
identical output except for superior formatting of constant pool entries.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84582 91177308-0d34-0410-b5e6-96231b3b80d8

get fancy: support basic block operands.  Yay for jumps.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84579 91177308-0d34-0410-b5e6-96231b3b80d8

add supprort for the 'sbit' operand, MOVi apparently has one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84577 91177308-0d34-0410-b5e6-96231b3b80d8

add support for instruction predicates.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84575 91177308-0d34-0410-b5e6-96231b3b80d8

implement printSORegOperand, add lowering for the nasty and despicable MOVi2pieces :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84573 91177308-0d34-0410-b5e6-96231b3b80d8

Refs: A8-598.
Leave Inst{11-8}, which represents the starting byte index of the extracted
result in the concatenation of the operands and is left unspecified.

Patch by Johnny Chen.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84572 91177308-0d34-0410-b5e6-96231b3b80d8

Add missing encoding bits to NLdSt class of instructions.

Patch by Johnny Chen.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84570 91177308-0d34-0410-b5e6-96231b3b80d8

X86 should ignore implicit regs when lowering to MCInst also,
no functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84567 91177308-0d34-0410-b5e6-96231b3b80d8

handle addmode4 modifiers, fix a fixme in printRegisterList
by ignoring all implicit regs when lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84566 91177308-0d34-0410-b5e6-96231b3b80d8

simplify by using the twine form of GetOrCreateSymbol

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84565 91177308-0d34-0410-b5e6-96231b3b80d8

Updated cmake library dependencies.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84564 91177308-0d34-0410-b5e6-96231b3b80d8

Enable allocation of R3 in Thumb1

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84563 91177308-0d34-0410-b5e6-96231b3b80d8

use EmitLabel instead of text emission

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84562 91177308-0d34-0410-b5e6-96231b3b80d8

add a twine version of MCContext::GetOrCreateSymbol.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84561 91177308-0d34-0410-b5e6-96231b3b80d8

lower the ARM::CONSTPOOL_ENTRY pseudo op, giving us constant pool entries
like:

@ BB#1:
.align 2
LCPI1_0:
.long L_.str-(LPC0+8)

Note that proper indentation of the label :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84558 91177308-0d34-0410-b5e6-96231b3b80d8

Adjust the scavenge register spilling to allow the target to choose an
appropriate restore location for the spill as well as perform the actual
save and restore.

The Thumb1 target uses this to make sure R12 is not clobbered while a spilled
scavenger register is live there.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84554 91177308-0d34-0410-b5e6-96231b3b80d8

add MCInstLower support for lowering ARM::PICADD, a pseudo op for pic stuffola.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84553 91177308-0d34-0410-b5e6-96231b3b80d8

Refactor lookup_or_add to contain _MUCH_ less duplicated code.  Add support for
numbering first class aggregate instructions while we're at it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84547 91177308-0d34-0410-b5e6-96231b3b80d8

add register list and hacked up addrmode #4 support, we now get this:

_main:
stmsp! sp!, {r7, lr}
mov r7, sp
sub sp, sp, #4
mov r0, #0
str r0, [sp]
ldr r0, LCPI1_0
bl _printf
ldr r0, [sp]
mov sp, r7
ldmsp! sp!, {r7, pc}

Note the unhappy ldm/stm because of modifiers being ignored.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84546 91177308-0d34-0410-b5e6-96231b3b80d8

revert r84540, fixing build breakage I didn't see because of
broken makefile deps :(

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84544 91177308-0d34-0410-b5e6-96231b3b80d8

add addrmode2 support, getting us up to:

_main:
stm ,
mov r7, sp
sub sp, sp, #4
mov r0, #0
str r0, [sp]
ldr r0, LCPI1_0
bl _printf
ldr r0, [sp]
mov sp, r7
ldm ,

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84543 91177308-0d34-0410-b5e6-96231b3b80d8

add jump tables, constant pools and some trivial global
lowering stuff.  We can now compile hello world to:

_main:
stm ,
mov r7, sp
sub sp, sp, #4
mov r0, #0
str r0,
ldr r0,
bl _printf
ldr r0,
mov sp, r7
ldm ,

Almost looks like arm code :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84542 91177308-0d34-0410-b5e6-96231b3b80d8

Malloc calls are marked NoAlias, so the code below the isMalloc() check makes it redundant.  Removing the isMalloc() check.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84541 91177308-0d34-0410-b5e6-96231b3b80d8

pass mangler in as a reference instead of a pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84540 91177308-0d34-0410-b5e6-96231b3b80d8

More refactoring...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84537 91177308-0d34-0410-b5e6-96231b3b80d8

reduce #includes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84536 91177308-0d34-0410-b5e6-96231b3b80d8

add printing support for SOImm operands, getting us to:

_main:
stm ,
mov r7, sp
sub sp, sp, #4
mov r0, #0
str r0,

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84535 91177308-0d34-0410-b5e6-96231b3b80d8

Simplify some code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84533 91177308-0d34-0410-b5e6-96231b3b80d8

wire up some basic printOperand goodness, giving us stuff like this before
we abort:

_main:
stm ,
mov r7, sp
sub sp, sp,
mov r0,
str r0,

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84532 91177308-0d34-0410-b5e6-96231b3b80d8

add the files that go with the previous rev

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84531 91177308-0d34-0410-b5e6-96231b3b80d8

wire up skeletal support for having llc print instructions
through mcinst lowering -> mcinstprinter, when llc is passed
the -enable-arm-mcinst-printer flag.  Currently this
is very "aborty".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84530 91177308-0d34-0410-b5e6-96231b3b80d8

Banish ConstantsLock.  It's serving no purpose other than slowing things down
at the moment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84529 91177308-0d34-0410-b5e6-96231b3b80d8

wire up ARM's printMCInst method.  Now llvm-mc should be able to produce
"something" when printing MCInsts, it will just be missing all the
operand info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84528 91177308-0d34-0410-b5e6-96231b3b80d8

stub out a minimal ARMInstPrinter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84527 91177308-0d34-0410-b5e6-96231b3b80d8

remove strings from instructions who are never asmprinted.
All of these "subreg32" modifier instructions are handled
explicitly by the MCInst lowering phase.  If they got to
the asmprinter, they would explode.  They should eventually
be replace with correct use of subregs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84526 91177308-0d34-0410-b5e6-96231b3b80d8

Clean up the JITResolver stub/callsite<->function maps.

The JITResolver maps Functions to their canonical stubs and all callsites for
lazily-compiled functions to their target Functions. To make Function
destruction work, I'm going to need to remove all callsites on destruction, so
this patch also adds the reverse mapping for that.

There was an incorrect assumption in here that the only stub for a function
would be the one caused by needing to lazily compile it, while x86-64 far calls
and dlsym-stubs could also cause such stubs, but I didn't look for a test case
that the assumption broke.

This also adds DenseMapInfo<AssertingVH> so I can use DenseMaps instead of
std::maps.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84522 91177308-0d34-0410-b5e6-96231b3b80d8

simplify code, reducing string thrashing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84521 91177308-0d34-0410-b5e6-96231b3b80d8

switch hidden gv stubs to use MachineModuleInfoMachO instead of a custom map.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84520 91177308-0d34-0410-b5e6-96231b3b80d8

use MachineModuleInfoMachO for non-lazy gv stubs instead of a private map.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84519 91177308-0d34-0410-b5e6-96231b3b80d8

convert to filecheck syntax and make a lot more aggressive.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84517 91177308-0d34-0410-b5e6-96231b3b80d8

Revert r84295, this unbreaks llvm-gcc bootstrap on x86-64/linux

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84516 91177308-0d34-0410-b5e6-96231b3b80d8

rename test

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84515 91177308-0d34-0410-b5e6-96231b3b80d8

remove dead map

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84513 91177308-0d34-0410-b5e6-96231b3b80d8

don't bother trying to avoid emitting redundant constant pool alignment directives.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84512 91177308-0d34-0410-b5e6-96231b3b80d8

remove accidental comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84510 91177308-0d34-0410-b5e6-96231b3b80d8

emit .subsections_via_symbols through MCStreamer instead of textually.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84509 91177308-0d34-0410-b5e6-96231b3b80d8

cleanup doFinalization -> EmitEndOfAsmFile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84508 91177308-0d34-0410-b5e6-96231b3b80d8

Tweak top-level Makefile to facilitate Apple-style build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84507 91177308-0d34-0410-b5e6-96231b3b80d8

PR 5245 - The imediate size target flag was not set on 3A-prefixed SSSE3 instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84506 91177308-0d34-0410-b5e6-96231b3b80d8

Fix SplitBlockPredecessors' LoopInfo updating code to handle the case
where a loop's header is being split and it has predecessors which are not
contained by the most-nested loop which contains the loop.
This fixes PR5235.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84505 91177308-0d34-0410-b5e6-96231b3b80d8

Fix a typo in a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84504 91177308-0d34-0410-b5e6-96231b3b80d8

Change a few instance variables to be local variables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84503 91177308-0d34-0410-b5e6-96231b3b80d8

Change instnamer to name arguments "arg" instead of "tmp" for clarity, and
to name basic blocks "bb" instead of "BB", for consistency.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84502 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Add -parallel-test option, which runs llvm-test with
ENABLE_PARALLEL_REPORT.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84497 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Don't hard code -l3.0 argument to make, this is very server dependent. Users who care can use -compileflags for this.

Also, fix make clean call and a few other tweaks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84496 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Fix refactoro, I dropped the list of all (llvm-test) tests. I'm sure it was named dejagnu_test_list for a good reason.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84495 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Lift conditional logic out of test steps.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84494 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Now that build & test steps are factored out, coalesce all the logic together.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84493 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Sink code for running nightly test into subroutine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84492 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Tweaks and simplifications.
 - Split out configure log.
 - Kill off GetRegexNum.
 - Fix GetRegex to not return previous match on failure.
 - Remove dead code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84491 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Move build code into subroutine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84490 91177308-0d34-0410-b5e6-96231b3b80d8

NNT: Move source checkout code into subroutine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84489 91177308-0d34-0410-b5e6-96231b3b80d8