llvm/lib/CodeGen
Juergen Ributzka 933d703d7c Reduce code duplication between patchpoint and non-patchpoint lowering. NFC.
This is in preparation for another patch that makes patchpoints invokable.

Reviewers: atrick, ributzka
Reviewed By: ributzka
Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5657

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219967 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-16 21:26:35 +00:00
..
AsmPrinter Simplify handling of --noexecstack by using getNonexecutableStackSection. 2014-10-15 16:12:52 +00:00
SelectionDAG Reduce code duplication between patchpoint and non-patchpoint lowering. NFC. 2014-10-16 21:26:35 +00:00
AggressiveAntiDepBreaker.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
AggressiveAntiDepBreaker.h mop up: "Don’t duplicate function or class name at the beginning of the comment." 2014-09-21 14:48:16 +00:00
AllocationOrder.cpp
AllocationOrder.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
Analysis.cpp Remove the TargetMachine forwards for TargetSubtargetInfo based 2014-08-04 21:25:23 +00:00
AntiDepBreaker.h mop up: "Don’t duplicate function or class name at the beginning of the comment." 2014-09-21 14:48:16 +00:00
AtomicExpandPass.cpp Lower idempotent RMWs to fence+load 2014-09-25 17:27:43 +00:00
BasicTargetTransformInfo.cpp Add a new pass FunctionTargetTransformInfo. This pass serves as a 2014-09-18 00:34:14 +00:00
BranchFolding.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
BranchFolding.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
CalcSpillWeights.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
CallingConvLower.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
CMakeLists.txt [MCJIT] Nuke MachineRelocation and MachineCodeEmitter. Now that the old JIT is 2014-09-23 18:08:47 +00:00
CodeGen.cpp Rename AtomicExpandLoadLinked into AtomicExpand 2014-08-21 21:50:01 +00:00
CodeGenPrepare.cpp [CodeGenPrepare][AddressingModeMatcher] The promotion mechanism was expecting 2014-09-16 22:36:07 +00:00
CriticalAntiDepBreaker.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
CriticalAntiDepBreaker.h mop up: "Don’t duplicate function or class name at the beginning of the comment." 2014-09-21 14:48:16 +00:00
DeadMachineInstructionElim.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
DFAPacketizer.cpp Remove the TargetMachine from DFAPacketizer since it was only 2014-10-14 01:03:16 +00:00
DwarfEHPrepare.cpp In DwarfEHPrepare, after all passes are run, RewindFunction may be a dangling 2014-09-14 20:36:28 +00:00
EarlyIfConversion.cpp Change MCSchedModel to be a struct of statically initialized data. 2014-09-02 17:43:54 +00:00
EdgeBundles.cpp
ErlangGC.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
ExecutionDepsFix.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
ExpandISelPseudos.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
ExpandPostRAPseudos.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
GCMetadata.cpp
GCMetadataPrinter.cpp
GCStrategy.cpp Remove the TargetMachine forwards for TargetSubtargetInfo based 2014-08-04 21:25:23 +00:00
GlobalMerge.cpp Remove the TargetMachine forwards for TargetSubtargetInfo based 2014-08-04 21:25:23 +00:00
IfConversion.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
InlineSpiller.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
InterferenceCache.cpp
InterferenceCache.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
IntrinsicLowering.cpp [PATCH][Interpreter] Add missing FP intrinsic lowering. 2014-08-30 18:33:35 +00:00
JumpInstrTables.cpp Don't manually (and forcibly) run the verifier on the entire module from 2014-07-30 05:44:04 +00:00
LatencyPriorityQueue.cpp
LexicalScopes.cpp DebugInfo: Ensure that all debug location scope chains from instructions within a function, lead to the function itself. 2014-10-14 18:22:52 +00:00
LiveDebugVariables.cpp Move the complex address expression out of DIVariable and into an extra 2014-10-01 18:55:02 +00:00
LiveDebugVariables.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
LiveInterval.cpp
LiveIntervalAnalysis.cpp Access the subtarget off of the MachineFunction rather than 2014-10-14 06:26:53 +00:00
LiveIntervalUnion.cpp
LivePhysRegs.cpp
LiveRangeCalc.cpp
LiveRangeCalc.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
LiveRangeEdit.cpp Add TargetInstrInfo interface isAsCheapAsAMove. 2014-07-29 01:55:19 +00:00
LiveRegMatrix.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
LiveStackAnalysis.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
LiveVariables.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
LLVMBuild.txt
LLVMTargetMachine.cpp Simplify handling of --noexecstack by using getNonexecutableStackSection. 2014-10-15 16:12:52 +00:00
LocalStackSlotAllocation.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
MachineBasicBlock.cpp [MachineDominatorTree] Provide a method to inform a MachineDominatorTree that a 2014-08-13 21:00:07 +00:00
MachineBlockFrequencyInfo.cpp
MachineBlockPlacement.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
MachineBranchProbabilityInfo.cpp
MachineCombiner.cpp Change MCSchedModel to be a struct of statically initialized data. 2014-09-02 17:43:54 +00:00
MachineCopyPropagation.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
MachineCSE.cpp In Machine CSE pass, the source register of a COPY machine instruction can 2014-08-11 05:17:19 +00:00
MachineDominanceFrontier.cpp Templatify DominanceFrontier. 2014-07-12 21:59:52 +00:00
MachineDominators.cpp [MachineDominatorTree] Provide a method to inform a MachineDominatorTree that a 2014-08-13 21:00:07 +00:00
MachineFunction.cpp Remove unused member variable. 2014-10-14 18:53:16 +00:00
MachineFunctionAnalysis.cpp Remove unused member variable. 2014-10-14 18:53:16 +00:00
MachineFunctionPass.cpp
MachineFunctionPrinterPass.cpp
MachineInstr.cpp Revert "Revert "DI: Fold constant arguments into a single MDString"" 2014-10-03 20:01:09 +00:00
MachineInstrBundle.cpp Have MachineInstrBundle use the MachineFunction for subtarget 2014-10-14 06:26:55 +00:00
MachineLICM.cpp Remove the use and member variable of the TargetMachine from 2014-10-14 06:26:57 +00:00
MachineLoopInfo.cpp
MachineModuleInfo.cpp Delete dead code. NFC. 2014-08-15 14:58:22 +00:00
MachineModuleInfoImpls.cpp
MachinePassRegistry.cpp
MachinePostDominators.cpp
MachineRegionInfo.cpp Header hygiene: remove using directive and #undef DEBUG_TYPE once we're done. 2014-07-30 00:25:24 +00:00
MachineRegisterInfo.cpp CodeGen: switch raw array to std::vector 2014-08-25 00:28:31 +00:00
MachineScheduler.cpp Access the subtarget off of the MachineFunction via the DAG 2014-10-14 06:56:25 +00:00
MachineSink.cpp [MachineSink] Use the real post dominator tree 2014-10-15 03:27:43 +00:00
MachineSSAUpdater.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
MachineTraceMetrics.cpp Change MCSchedModel to be a struct of statically initialized data. 2014-09-02 17:43:54 +00:00
MachineVerifier.cpp Access subtarget specific variables off of the MachineFunction's 2014-10-14 07:00:33 +00:00
Makefile
module.modulemap
OcamlGC.cpp
OptimizePHIs.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
Passes.cpp Add pass-manager flags to use CFL AA 2014-09-02 22:12:54 +00:00
PeepholeOptimizer.cpp Avoid caching the MachineFunction, we don't use it outside of 2014-10-15 21:06:25 +00:00
PHIElimination.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
PHIEliminationUtils.cpp
PHIEliminationUtils.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
PostRASchedulerList.cpp Grab the subtarget and subtarget dependent variables off of 2014-10-14 07:17:23 +00:00
ProcessImplicitDefs.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
PrologEpilogInserter.cpp Grab the subtarget and subtarget dependent variables off of 2014-10-14 07:17:23 +00:00
PrologEpilogInserter.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
PseudoSourceValue.cpp Make isAliased property for fixed-offset stack objects adjustable 2014-08-16 00:17:02 +00:00
README.txt
RegAllocBase.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
RegAllocBase.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
RegAllocBasic.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
RegAllocFast.cpp Grab the subtarget and subtarget dependent variables off of 2014-10-14 07:22:00 +00:00
RegAllocGreedy.cpp Grab the subtarget and subtarget dependent variables off of 2014-10-14 07:22:00 +00:00
RegAllocPBQP.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
RegisterClassInfo.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
RegisterCoalescer.cpp delete function names from comments 2014-10-09 21:24:46 +00:00
RegisterCoalescer.h mop up: "Don’t duplicate function or class name at the beginning of the comment." 2014-09-20 22:39:16 +00:00
RegisterPressure.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
RegisterScavenging.cpp Grab the subtarget and subtarget dependent variables off of 2014-10-14 07:22:00 +00:00
ScheduleDAG.cpp Remove the TargetMachine forwards for TargetSubtargetInfo based 2014-08-04 21:25:23 +00:00
ScheduleDAGInstrs.cpp Remove an unnecessary restriction. MIsNeedChainEdge() should be checked even when scheduler AliasAnalysis is not 2014-09-12 21:17:55 +00:00
ScheduleDAGPrinter.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
ScoreboardHazardRecognizer.cpp Change MCSchedModel to be a struct of statically initialized data. 2014-09-02 17:43:54 +00:00
ShadowStackGC.cpp
SjLjEHPrepare.cpp Use range based for loops to avoid needing to re-mention SmallPtrSet size. 2014-08-24 23:23:06 +00:00
SlotIndexes.cpp
Spiller.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
Spiller.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
SpillPlacement.cpp Fix the threshold added in r186434 (a re-apply of r185393) and updaated 2014-10-02 22:23:14 +00:00
SpillPlacement.h Fix the threshold added in r186434 (a re-apply of r185393) and updaated 2014-10-02 22:23:14 +00:00
SplitKit.cpp Grab the subtarget and subtarget dependent variables off of 2014-10-14 07:22:00 +00:00
SplitKit.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
StackColoring.cpp Fix typos in comments, NFC 2014-08-29 21:53:01 +00:00
StackMapLivenessAnalysis.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
StackMaps.cpp Remove unnecessary copying or replace it with moves in a bunch of places. 2014-10-04 16:55:56 +00:00
StackProtector.cpp Remove the TargetMachine forwards for TargetSubtargetInfo based 2014-08-04 21:25:23 +00:00
StackSlotColoring.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
TailDuplication.cpp Have MachineFunction cache a pointer to the subtarget to make lookups 2014-08-05 02:39:49 +00:00
TargetFrameLoweringImpl.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
TargetInstrInfo.cpp Fix a lot of confusion around inserting nops on empty functions. 2014-09-15 18:32:58 +00:00
TargetLoweringBase.cpp Reinstate "Nuke the old JIT." 2014-09-02 22:28:02 +00:00
TargetLoweringObjectFileImpl.cpp MC: ReadOnlyWithRel section kinds should map to rdata in COFF 2014-09-22 20:39:23 +00:00
TargetOptionsImpl.cpp
TargetRegisterInfo.cpp
TargetSchedule.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
TwoAddressInstructionPass.cpp Remove the TargetMachine forwards for TargetSubtargetInfo based 2014-08-04 21:25:23 +00:00
UnreachableBlockElim.cpp Use range based for loops to avoid needing to re-mention SmallPtrSet size. 2014-08-24 23:23:06 +00:00
VirtRegMap.cpp Migrate another set of getSubtargetImpl away. 2014-10-13 21:57:44 +00:00

//===---------------------------------------------------------------------===//

Common register allocation / spilling problem:

        mul lr, r4, lr
        str lr, [sp, #+52]
        ldr lr, [r1, #+32]
        sxth r3, r3
        ldr r4, [sp, #+52]
        mla r4, r3, lr, r4

can be:

        mul lr, r4, lr
        mov r4, lr
        str lr, [sp, #+52]
        ldr lr, [r1, #+32]
        sxth r3, r3
        mla r4, r3, lr, r4

and then "merge" mul and mov:

        mul r4, r4, lr
        str r4, [sp, #+52]
        ldr lr, [r1, #+32]
        sxth r3, r3
        mla r4, r3, lr, r4

It also increase the likelihood the store may become dead.

//===---------------------------------------------------------------------===//

bb27 ...
        ...
        %reg1037 = ADDri %reg1039, 1
        %reg1038 = ADDrs %reg1032, %reg1039, %NOREG, 10
    Successors according to CFG: 0x8b03bf0 (#5)

bb76 (0x8b03bf0, LLVM BB @0x8b032d0, ID#5):
    Predecessors according to CFG: 0x8b0c5f0 (#3) 0x8b0a7c0 (#4)
        %reg1039 = PHI %reg1070, mbb<bb76.outer,0x8b0c5f0>, %reg1037, mbb<bb27,0x8b0a7c0>

Note ADDri is not a two-address instruction. However, its result %reg1037 is an
operand of the PHI node in bb76 and its operand %reg1039 is the result of the
PHI node. We should treat it as a two-address code and make sure the ADDri is
scheduled after any node that reads %reg1039.

//===---------------------------------------------------------------------===//

Use local info (i.e. register scavenger) to assign it a free register to allow
reuse:
        ldr r3, [sp, #+4]
        add r3, r3, #3
        ldr r2, [sp, #+8]
        add r2, r2, #2
        ldr r1, [sp, #+4]  <==
        add r1, r1, #1
        ldr r0, [sp, #+4]
        add r0, r0, #2

//===---------------------------------------------------------------------===//

LLVM aggressively lift CSE out of loop. Sometimes this can be negative side-
effects:

R1 = X + 4
R2 = X + 7
R3 = X + 15

loop:
load [i + R1]
...
load [i + R2]
...
load [i + R3]

Suppose there is high register pressure, R1, R2, R3, can be spilled. We need
to implement proper re-materialization to handle this:

R1 = X + 4
R2 = X + 7
R3 = X + 15

loop:
R1 = X + 4  @ re-materialized
load [i + R1]
...
R2 = X + 7 @ re-materialized
load [i + R2]
...
R3 = X + 15 @ re-materialized
load [i + R3]

Furthermore, with re-association, we can enable sharing:

R1 = X + 4
R2 = X + 7
R3 = X + 15

loop:
T = i + X
load [T + 4]
...
load [T + 7]
...
load [T + 15]
//===---------------------------------------------------------------------===//

It's not always a good idea to choose rematerialization over spilling. If all
the load / store instructions would be folded then spilling is cheaper because
it won't require new live intervals / registers. See 2003-05-31-LongShifts for
an example.

//===---------------------------------------------------------------------===//

With a copying garbage collector, derived pointers must not be retained across
collector safe points; the collector could move the objects and invalidate the
derived pointer. This is bad enough in the first place, but safe points can
crop up unpredictably. Consider:

        %array = load { i32, [0 x %obj] }** %array_addr
        %nth_el = getelementptr { i32, [0 x %obj] }* %array, i32 0, i32 %n
        %old = load %obj** %nth_el
        %z = div i64 %x, %y
        store %obj* %new, %obj** %nth_el

If the i64 division is lowered to a libcall, then a safe point will (must)
appear for the call site. If a collection occurs, %array and %nth_el no longer
point into the correct object.

The fix for this is to copy address calculations so that dependent pointers
are never live across safe point boundaries. But the loads cannot be copied
like this if there was an intervening store, so may be hard to get right.

Only a concurrent mutator can trigger a collection at the libcall safe point.
So single-threaded programs do not have this requirement, even with a copying
collector. Still, LLVM optimizations would probably undo a front-end's careful
work.

//===---------------------------------------------------------------------===//

The ocaml frametable structure supports liveness information. It would be good
to support it.

//===---------------------------------------------------------------------===//

The FIXME in ComputeCommonTailLength in BranchFolding.cpp needs to be
revisited. The check is there to work around a misuse of directives in inline
assembly.

//===---------------------------------------------------------------------===//

It would be good to detect collector/target compatibility instead of silently
doing the wrong thing.

//===---------------------------------------------------------------------===//

It would be really nice to be able to write patterns in .td files for copies,
which would eliminate a bunch of explicit predicates on them (e.g. no side 
effects).  Once this is in place, it would be even better to have tblgen 
synthesize the various copy insertion/inspection methods in TargetInstrInfo.

//===---------------------------------------------------------------------===//

Stack coloring improvements:

1. Do proper LiveStackAnalysis on all stack objects including those which are
   not spill slots.
2. Reorder objects to fill in gaps between objects.
   e.g. 4, 1, <gap>, 4, 1, 1, 1, <gap>, 4 => 4, 1, 1, 1, 1, 4, 4

//===---------------------------------------------------------------------===//

The scheduler should be able to sort nearby instructions by their address. For
example, in an expanded memset sequence it's not uncommon to see code like this:

  movl $0, 4(%rdi)
  movl $0, 8(%rdi)
  movl $0, 12(%rdi)
  movl $0, 0(%rdi)

Each of the stores is independent, and the scheduler is currently making an
arbitrary decision about the order.

//===---------------------------------------------------------------------===//

Another opportunitiy in this code is that the $0 could be moved to a register:

  movl $0, 4(%rdi)
  movl $0, 8(%rdi)
  movl $0, 12(%rdi)
  movl $0, 0(%rdi)

This would save substantial code size, especially for longer sequences like
this. It would be easy to have a rule telling isel to avoid matching MOV32mi
if the immediate has more than some fixed number of uses. It's more involved
to teach the register allocator how to do late folding to recover from
excessive register pressure.