mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-26 06:29:20 +00:00
8fa8929177
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
|
||
|---|---|---|
| .. | ||
| ADCE.cpp | ||
| BasicBlockPlacement.cpp | ||
| CodeGenPrepare.cpp | ||
| CondPropagate.cpp | ||
| ConstantProp.cpp | ||
| CorrelatedExprs.cpp | ||
| DCE.cpp | ||
| DeadStoreElimination.cpp | ||
| GCSE.cpp | ||
| GVN.cpp | ||
| GVNPRE.cpp | ||
| IndVarSimplify.cpp | ||
| InstructionCombining.cpp | ||
| LICM.cpp | ||
| LoopIndexSplit.cpp | ||
| LoopRotation.cpp | ||
| LoopStrengthReduce.cpp | ||
| LoopUnroll.cpp | ||
| LoopUnswitch.cpp | ||
| LowerGC.cpp | ||
| LowerPacked.cpp | ||
| Makefile | ||
| PredicateSimplifier.cpp | ||
| Reassociate.cpp | ||
| Reg2Mem.cpp | ||
| ScalarReplAggregates.cpp | ||
| SCCP.cpp | ||
| SimplifyCFG.cpp | ||
| TailDuplication.cpp | ||
| TailRecursionElimination.cpp | ||