6e54fccede
The instruction-precise, or asynchronous, unwind tables usually take up much more space than the synchronous ones. If a user is concerned about the load size of the program and does not need the features provided with the asynchronous tables, the compiler should be able to generate the more compact variant. This patch changes the generation of CFI instructions for these cases so that they all come in one chunk in the prolog; it emits only one `.cfi_def_cfa*` instruction followed by `.cfi_offset` ones after all stack adjustments and register spills, and avoids generating CFI instructions in the epilog(s) as well as any other exceeding CFI instructions like `.cfi_remember_state` and `.cfi_restore_state`. Effectively, it reverses the effects of D111411 and D114545 on functions with the `uwtable(sync)` attribute. As a side effect, it also restores the behavior on functions that have neither `uwtable` nor `nounwind` attributes. Differential Revision: https://reviews.llvm.org/D153098
55 lines
2.0 KiB
LLVM
55 lines
2.0 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=arm64-apple-ios -relocation-model=pic -frame-pointer=all | FileCheck %s
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@__stack_chk_guard = external global ptr
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; PR20558
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; Load the stack guard for the second time, just in case the previous value gets spilled.
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define i32 @test_stack_guard_remat2() ssp {
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; CHECK-LABEL: test_stack_guard_remat2:
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; CHECK: ; %bb.0: ; %entry
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; CHECK-NEXT: sub sp, sp, #64
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; CHECK-NEXT: stp x29, x30, [sp, #48] ; 16-byte Folded Spill
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; CHECK-NEXT: add x29, sp, #48
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; CHECK-NEXT: .cfi_def_cfa w29, 16
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; CHECK-NEXT: .cfi_offset w30, -8
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; CHECK-NEXT: .cfi_offset w29, -16
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; CHECK-NEXT: Lloh0:
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; CHECK-NEXT: adrp x8, ___stack_chk_guard@GOTPAGE
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; CHECK-NEXT: Lloh1:
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; CHECK-NEXT: adrp x9, ___stack_chk_guard@GOTPAGE
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; CHECK-NEXT: Lloh2:
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; CHECK-NEXT: ldr x8, [x8, ___stack_chk_guard@GOTPAGEOFF]
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; CHECK-NEXT: Lloh3:
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; CHECK-NEXT: ldr x9, [x9, ___stack_chk_guard@GOTPAGEOFF]
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; CHECK-NEXT: Lloh4:
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; CHECK-NEXT: ldr x8, [x8]
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; CHECK-NEXT: Lloh5:
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; CHECK-NEXT: ldr x9, [x9]
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; CHECK-NEXT: str x8, [sp]
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; CHECK-NEXT: stur x9, [x29, #-8]
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; CHECK-NEXT: ldur x9, [x29, #-8]
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; CHECK-NEXT: cmp x8, x9
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; CHECK-NEXT: b.ne LBB0_2
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; CHECK-NEXT: ; %bb.1: ; %entry
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; CHECK-NEXT: ldp x29, x30, [sp, #48] ; 16-byte Folded Reload
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; CHECK-NEXT: mov w0, #-1
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; CHECK-NEXT: add sp, sp, #64
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; CHECK-NEXT: ret
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; CHECK-NEXT: LBB0_2: ; %entry
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; CHECK-NEXT: bl ___stack_chk_fail
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; CHECK-NEXT: .loh AdrpLdrGotLdr Lloh1, Lloh3, Lloh5
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; CHECK-NEXT: .loh AdrpLdrGotLdr Lloh0, Lloh2, Lloh4
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entry:
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%StackGuardSlot = alloca ptr
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%StackGuard = load ptr, ptr @__stack_chk_guard
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call void @llvm.stackprotector(ptr %StackGuard, ptr %StackGuardSlot)
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%container = alloca [32 x i8], align 1
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call void @llvm.stackprotectorcheck(ptr @__stack_chk_guard)
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ret i32 -1
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}
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declare void @llvm.stackprotector(ptr, ptr) ssp
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declare void @llvm.stackprotectorcheck(ptr) ssp
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