mirror of
https://github.com/c64scene-ar/llvm-6502.git
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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
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| .. | ||
| ADT | ||
| Analysis | ||
| Assembly | ||
| Bitcode | ||
| CodeGen | ||
| Config | ||
| Debugger | ||
| ExecutionEngine | ||
| Support | ||
| System | ||
| Target | ||
| Transforms | ||
| AbstractTypeUser.h | ||
| Argument.h | ||
| AutoUpgrade.h | ||
| BasicBlock.h | ||
| CallGraphSCCPass.h | ||
| CallingConv.h | ||
| Constant.h | ||
| Constants.h | ||
| DerivedTypes.h | ||
| Function.h | ||
| GlobalAlias.h | ||
| GlobalValue.h | ||
| GlobalVariable.h | ||
| InlineAsm.h | ||
| InstrTypes.h | ||
| Instruction.def | ||
| Instruction.h | ||
| Instructions.h | ||
| IntrinsicInst.h | ||
| Intrinsics.h | ||
| Intrinsics.td | ||
| IntrinsicsARM.td | ||
| IntrinsicsCellSPU.td | ||
| IntrinsicsPowerPC.td | ||
| IntrinsicsX86.td | ||
| LinkAllPasses.h | ||
| LinkAllVMCore.h | ||
| Linker.h | ||
| LinkTimeOptimizer.h | ||
| Module.h | ||
| ModuleProvider.h | ||
| ParameterAttributes.h | ||
| Pass.h | ||
| PassAnalysisSupport.h | ||
| PassManager.h | ||
| PassManagers.h | ||
| PassSupport.h | ||
| SymbolTableListTraits.h | ||
| Type.h | ||
| TypeSymbolTable.h | ||
| Use.h | ||
| User.h | ||
| Value.h | ||
| ValueSymbolTable.h | ||