llvm-6502/lib/CodeGen
Rafael Espindola 2fa06b171b Add support for having multiple sections with the same name and comdat.
Using this in combination with -ffunction-sections allows LLVM to output a .o
file with mulitple sections named .text. This saves space by avoiding long
unique names of the form .text.<C++ mangled name>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228980 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-12 23:29:51 +00:00
..
AsmPrinter On ELF, put PIC jump tables in a non executable section. 2015-02-12 17:46:49 +00:00
SelectionDAG [SDAG] Don't try to use FP_EXTEND/FP_ROUND for int<->fp promotions 2015-02-12 22:43:52 +00:00
AggressiveAntiDepBreaker.cpp Correct the AggressiveAntiDepBreaker's handling of subregisters defining super registers 2015-01-28 14:44:14 +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 Add assertions for out of bound index in ComputeLinearIndex 2015-01-14 05:38:48 +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 Migrate AtomicExpandPass and DwarfEHPrepare to using a Function-ized getSubtargetImpl. 2015-01-27 01:04:42 +00:00
BasicTargetTransformInfo.cpp [multiversion] Switch the TTI queries from TargetMachine to Subtarget 2015-02-01 14:22:17 +00:00
BranchFolding.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
BranchFolding.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
CalcSpillWeights.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
CallingConvLower.cpp musttail: Only set the inreg flag for fastcall and vectorcall 2015-01-12 23:28:23 +00:00
CMakeLists.txt Use ADDITIONAL_HEADER_DIRS in all LLVM CMake projects. 2015-02-11 03:28:02 +00:00
CodeGen.cpp [PM] Change the core design of the TTI analysis to use a polymorphic 2015-01-31 03:43:40 +00:00
CodeGenPrepare.cpp [multiversion] Thread a function argument through all the callers of the 2015-02-01 12:01:35 +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 Add the llvm.frameallocate and llvm.recoverframeallocation intrinsics 2015-01-13 00:48:10 +00:00
DFAPacketizer.cpp Remove the TargetMachine from DFAPacketizer since it was only 2014-10-14 01:03:16 +00:00
DwarfEHPrepare.cpp EHPrepare: Remove leftover initialization code for DomTrees. 2015-01-29 13:26:50 +00:00
EarlyIfConversion.cpp The subtarget is cached on the MachineFunction. Access it directly. 2015-01-27 07:31:29 +00:00
EdgeBundles.cpp
ErlangGC.cpp Revert GCStrategy ownership changes 2015-01-26 18:26:35 +00:00
ExecutionDepsFix.cpp ExecutionDepsFix: Correctly handle wide registers. 2014-12-17 19:13:47 +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
ForwardControlFlowIntegrity.cpp [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
GCMetadata.cpp Revert GCStrategy ownership changes 2015-01-26 18:26:35 +00:00
GCMetadataPrinter.cpp clang-format all the GC related files (NFC) 2015-01-16 23:16:12 +00:00
GCRootLowering.cpp Remove gc.root's performCustomLowering 2015-01-28 19:28:03 +00:00
GCStrategy.cpp Revert GCStrategy ownership changes 2015-01-26 18:26:35 +00:00
GlobalMerge.cpp [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
IfConversion.cpp The subtarget is cached on the MachineFunction. Access it directly. 2015-01-27 07:31:29 +00:00
InlineSpiller.cpp LiveIntervalAnalysis: Factor out code to update liveness on physreg def removal 2015-01-21 18:50:21 +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 [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +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 [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
LiveDebugVariables.h [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
LiveInterval.cpp [LiveIntervalAnalysis] Speed up creation of live ranges for physical registers 2015-02-06 18:42:41 +00:00
LiveIntervalAnalysis.cpp [LiveIntervalAnalysis] Speed up creation of live ranges for physical registers 2015-02-06 18:42:41 +00:00
LiveIntervalUnion.cpp LiveIntervalUnion: Allow specification of liverange when unifying/extracting. 2014-12-10 01:12:59 +00:00
LivePhysRegs.cpp
LiveRangeCalc.cpp LiveInterval: Introduce createMainRangeFromSubranges(). 2014-12-24 02:11:51 +00:00
LiveRangeCalc.h LiveRangeCalc: Rewrite subrange calculation 2014-12-16 04:03:38 +00:00
LiveRangeEdit.cpp MachineRegisterInfo can access TII off of the MachineFunction's 2015-01-27 01:15:16 +00:00
LiveRegMatrix.cpp [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
LiveStackAnalysis.cpp Move register class name strings to a single array in MCRegisterInfo to reduce static table size and number of relocation entries. 2014-11-17 05:50:14 +00:00
LiveVariables.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
LLVMBuild.txt
LLVMTargetMachine.cpp Only access TLOF via the TargetMachine, not TargetLowering. 2015-02-03 07:22:52 +00:00
LocalStackSlotAllocation.cpp [Statepoints 2/4] Statepoint infrastructure for garbage collection: MI & x86-64 Backend 2014-12-01 22:52:56 +00:00
MachineBasicBlock.cpp The leak detector is dead, long live asan and valgrind. 2014-12-22 13:00:36 +00:00
MachineBlockFrequencyInfo.cpp Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
MachineBlockPlacement.cpp [MBP] Add flags to disable the BadCFGConflict check in MachineBlockPlacement. 2015-01-14 20:19:29 +00:00
MachineBranchProbabilityInfo.cpp
MachineCombiner.cpp remove function names from comments; NFC 2015-01-27 22:26:56 +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 MachineCSE: Clear dead-def flag on CSE. 2015-02-04 19:35:16 +00:00
MachineDominanceFrontier.cpp [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +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 MergeableConst. 2015-01-29 14:12:41 +00:00
MachineFunctionAnalysis.cpp Remove unused member variable. 2014-10-14 18:53:16 +00:00
MachineFunctionPass.cpp [LPM] Stop using the string based preservation API. It is an 2015-01-28 04:57:56 +00:00
MachineFunctionPrinterPass.cpp Rename argument strings of codegen passes to avoid collisions with command line 2014-12-13 04:52:04 +00:00
MachineInstr.cpp Move DebugLocs around instead of copying. 2015-02-07 12:28:15 +00:00
MachineInstrBundle.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
MachineLICM.cpp Small cleanup of MachineLICM.cpp 2015-02-05 22:39:46 +00:00
MachineLoopInfo.cpp
MachineModuleInfo.cpp Classify functions by EH personality type rather than using the triple 2015-01-23 18:49:01 +00:00
MachineModuleInfoImpls.cpp
MachinePassRegistry.cpp
MachinePostDominators.cpp
MachineRegionInfo.cpp [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
MachineRegisterInfo.cpp MachineRegisterInfo can access TII off of the MachineFunction's 2015-01-27 01:15:16 +00:00
MachineScheduler.cpp The subtarget is cached on the MachineFunction. Access it directly. 2015-01-27 07:31:29 +00:00
MachineSink.cpp Use DomTree in MachineSink to sink over diamonds. 2014-12-04 10:36:42 +00:00
MachineSSAUpdater.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
MachineTraceMetrics.cpp The subtarget is cached on the MachineFunction. Access it directly. 2015-01-27 07:31:29 +00:00
MachineVerifier.cpp Remove a gross usage of environment variables in MachineVerifier, replacing it with support for setting the -verify-machineinstrs flag via an environment variable in LIT. 2015-02-04 00:02:59 +00:00
Makefile
module.modulemap [modules] Add module maps for LLVM. These are not quite ready for prime-time 2014-05-21 02:46:14 +00:00
OcamlGC.cpp Revert GCStrategy ownership changes 2015-01-26 18:26:35 +00:00
OptimizePHIs.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
Passes.cpp Remove a gross usage of environment variables in MachineVerifier, replacing it with support for setting the -verify-machineinstrs flag via an environment variable in LIT. 2015-02-04 00:02:59 +00:00
PeepholeOptimizer.cpp Peephole opt needs optimizeSelect() to keep track of newly created MIs 2015-01-13 07:07:13 +00:00
PHIElimination.cpp Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool> 2014-11-19 07:49:26 +00:00
PHIEliminationUtils.cpp
PHIEliminationUtils.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
PostRASchedulerList.cpp The subtarget is cached on the MachineFunction. Access it directly. 2015-01-27 07:31:29 +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 [X86] Convert esp-relative movs of function arguments to pushes, step 2 2015-02-01 16:56:04 +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 [RegAllocGreedy] Introduce a late pass to repair broken hints. 2015-01-08 01:16:39 +00:00
RegAllocBase.h [RegAllocGreedy] Introduce a late pass to repair broken hints. 2015-01-08 01:16:39 +00:00
RegAllocBasic.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
RegAllocFast.cpp [RegAllocFast] Handle implicit definitions conservatively. 2014-12-03 23:38:08 +00:00
RegAllocGreedy.cpp [RegAllocGreedy] Introduce a late pass to repair broken hints. 2015-01-08 01:16:39 +00:00
RegAllocPBQP.cpp [PBQP] Cautiously update edge costs in the solver 2015-02-11 08:25:36 +00:00
RegisterClassInfo.cpp Silence more static analyzer warnings. 2014-12-15 18:48:43 +00:00
RegisterCoalescer.cpp Update a few calls to getSubtarget<> to either be getSubtargetImpl 2015-01-27 07:54:39 +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 Replace some uses of getSubtargetImpl with the cached version 2015-01-27 08:48:42 +00:00
ScheduleDAGInstrs.cpp Bugfix for missed dependency from store to load in buildSchedGraph(). 2015-02-10 13:03:32 +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 Remove gc.root's performCustomLowering 2015-01-28 19:28:03 +00:00
ShadowStackGCLowering.cpp Remove gc.root's performCustomLowering 2015-01-28 19:28:03 +00:00
SjLjEHPrepare.cpp Replace some uses of getSubtargetImpl with the cached version 2015-01-27 08:48:42 +00:00
SlotIndexes.cpp
Spiller.h [RegAlloc] Kill off the trivial spiller - nobody is using it any more. 2014-11-06 19:12:38 +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 LiveIntervalAnalysis: Factor out code to update liveness on vreg def removal 2015-01-21 19:02:30 +00:00
SplitKit.h Canonicalize header guards into a common format. 2014-08-13 16:26:38 +00:00
StackColoring.cpp IR: Split Metadata from Value 2014-12-09 18:38:53 +00:00
StackMapLivenessAnalysis.cpp [StackMaps] Allow the target to pre-process the live-out mask 2015-01-13 17:47:59 +00:00
StackMaps.cpp Move DataLayout back to the TargetMachine from TargetSubtargetInfo 2015-01-26 19:03:15 +00:00
StackProtector.cpp Replace some uses of getSubtargetImpl with the cached version 2015-01-27 08:48:42 +00:00
StackSlotColoring.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
StatepointExampleGC.cpp Revert GCStrategy ownership changes 2015-01-26 18:26:35 +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 [X86] Convert esp-relative movs of function arguments to pushes, step 2 2015-02-01 16:56:04 +00:00
TargetInstrInfo.cpp Move DataLayout back to the TargetMachine from TargetSubtargetInfo 2015-01-26 19:03:15 +00:00
TargetLoweringBase.cpp Move DataLayout back to the TargetMachine from TargetSubtargetInfo 2015-01-26 19:03:15 +00:00
TargetLoweringObjectFileImpl.cpp Add support for having multiple sections with the same name and comdat. 2015-02-12 23:29:51 +00:00
TargetOptionsImpl.cpp Migrate ABIName to MCTargetOptions so that it can be shared between 2015-01-14 00:50:31 +00:00
TargetRegisterInfo.cpp Introduce register dump helper 2014-11-19 19:46:11 +00:00
TargetSchedule.cpp Remove unnecessary TargetMachine.h includes. 2014-10-14 07:22:08 +00:00
TwoAddressInstructionPass.cpp Replace some uses of getSubtargetImpl with the cached version 2015-01-27 08:48:42 +00:00
UnreachableBlockElim.cpp Replace size method call of containers to empty method where appropriate 2015-01-15 11:41:30 +00:00
VirtRegMap.cpp LiveInterval: Use range based for loops for subregister ranges. 2014-12-11 00:59:06 +00:00
WinEHPrepare.cpp Don't promote asynch EH invokes of nounwind functions to calls 2015-02-11 01:23:16 +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.