Gordon Henriksen 8fa8929177 With this patch, the LowerGC transformation becomes the ... ShadowStackCollector, which additionally has reduced overhead with no sacrifice in portability. Considering a function @fun with 8 loop-local roots, ShadowStackCollector introduces the following overhead (x86): ; shadowstack prologue movl L_llvm_gc_root_chain$non_lazy_ptr, %eax movl (%eax), %ecx movl $___gc_fun, 20(%esp) movl $0, 24(%esp) movl $0, 28(%esp) movl $0, 32(%esp) movl $0, 36(%esp) movl $0, 40(%esp) movl $0, 44(%esp) movl $0, 48(%esp) movl $0, 52(%esp) movl %ecx, 16(%esp) leal 16(%esp), %ecx movl %ecx, (%eax) ; shadowstack loop overhead (none) ; shadowstack epilogue movl 48(%esp), %edx movl %edx, (%ecx) ; shadowstack metadata .align 3 ___gc_fun: # __gc_fun .long 8 .space 4 In comparison to LowerGC: ; lowergc prologue movl L_llvm_gc_root_chain$non_lazy_ptr, %eax movl (%eax), %ecx movl %ecx, 48(%esp) movl $8, 52(%esp) movl $0, 60(%esp) movl $0, 56(%esp) movl $0, 68(%esp) movl $0, 64(%esp) movl $0, 76(%esp) movl $0, 72(%esp) movl $0, 84(%esp) movl $0, 80(%esp) movl $0, 92(%esp) movl $0, 88(%esp) movl $0, 100(%esp) movl $0, 96(%esp) movl $0, 108(%esp) movl $0, 104(%esp) movl $0, 116(%esp) movl $0, 112(%esp) ; lowergc loop overhead leal 44(%esp), %eax movl %eax, 56(%esp) leal 40(%esp), %eax movl %eax, 64(%esp) leal 36(%esp), %eax movl %eax, 72(%esp) leal 32(%esp), %eax movl %eax, 80(%esp) leal 28(%esp), %eax movl %eax, 88(%esp) leal 24(%esp), %eax movl %eax, 96(%esp) leal 20(%esp), %eax movl %eax, 104(%esp) leal 16(%esp), %eax movl %eax, 112(%esp) ; lowergc epilogue movl 48(%esp), %edx movl %edx, (%ecx) ; lowergc metadata (none) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45670 91177308-0d34-0410-b5e6-96231b3b80d8		2008-01-07 01:30:53 +00:00
..
AsmPrinter.h	Enabling the target-independent garbage collection infrastructure by hooking it	2008-01-07 01:30:38 +00:00
BreakCriticalMachineEdge.h
CallingConvLower.h
Collector.h
CollectorMetadata.h
Collectors.h
DwarfWriter.h
ELFRelocation.h
FileWriters.h
IntrinsicLowering.h
LinkAllCodegenComponents.h	With this patch, the LowerGC transformation becomes the	2008-01-07 01:30:53 +00:00
LiveInterval.h
LiveIntervalAnalysis.h	Rename SSARegMap -> MachineRegisterInfo in keeping with the idea	2007-12-31 04:13:23 +00:00
LiveVariables.h	More cleanups for MachineOperand:	2007-12-30 21:56:09 +00:00
MachineBasicBlock.h	properly encapsulate the parent field of MBB and MI with get/set accessors.	2007-12-31 04:56:33 +00:00
MachineCodeEmitter.h	X86 JIT PIC jumptable support.	2008-01-05 02:26:58 +00:00
MachineConstantPool.h
MachineDominators.h
MachineFrameInfo.h
MachineFunction.h	Rename SSARegMap -> MachineRegisterInfo in keeping with the idea	2007-12-31 04:13:23 +00:00
MachineFunctionPass.h
MachineInstr.h	Implement automatically updated def/use lists for all MachineInstr register	2008-01-01 01:12:31 +00:00
MachineInstrBuilder.h	Shrinkify the machine operand creation method names.	2007-12-30 00:45:46 +00:00
MachineJumpTableInfo.h
MachineLocation.h
MachineLoopInfo.h
MachineModuleInfo.h
MachineOperand.h	add efficient iteration support for register use/def's	2008-01-01 02:55:32 +00:00
MachinePassRegistry.h
MachineRegisterInfo.h	don't access element zero of an array of size zero.	2008-01-03 01:25:31 +00:00
MachineRelocation.h	X86 PIC JIT support fixes: encoding bugs, add lazy pointer stubs support.	2008-01-04 10:46:51 +00:00
MachORelocation.h
Passes.h	Don't recalculate the loop info and loop dominators analyses if they're	2008-01-04 20:54:55 +00:00
RegAllocRegistry.h
RegisterCoalescer.h
RegisterScavenging.h
RuntimeLibcalls.h
SchedGraphCommon.h
ScheduleDAG.h	Rename SSARegMap -> MachineRegisterInfo in keeping with the idea	2007-12-31 04:13:23 +00:00
SchedulerRegistry.h
SelectionDAG.h
SelectionDAGISel.h	Enabling the target-independent garbage collection infrastructure by hooking it	2008-01-07 01:30:38 +00:00
SelectionDAGNodes.h
ValueTypes.h
ValueTypes.td	remove attribution from a variety of miscellaneous files.	2007-12-29 22:59:10 +00:00