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
47 lines
1.3 KiB
LLVM
47 lines
1.3 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -mtriple=arm64-apple-ios %s -o - | FileCheck %s
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define void @foo() {
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; CHECK-LABEL: foo:
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; CHECK: ; %bb.0:
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; CHECK-NEXT: stp x28, x27, [sp, #-32]! ; 16-byte Folded Spill
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; CHECK-NEXT: stp x29, x30, [sp, #16] ; 16-byte Folded Spill
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; CHECK-NEXT: sub sp, sp, #1, lsl #12 ; =4096
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; CHECK-NEXT: sub sp, sp, #80
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; CHECK-NEXT: .cfi_def_cfa_offset 4208
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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: .cfi_offset w27, -24
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; CHECK-NEXT: .cfi_offset w28, -32
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; CHECK-NEXT: adds x8, sp, #1, lsl #12 ; =4096
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; CHECK-NEXT: cmn x8, #32
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; CHECK-NEXT: b.eq LBB0_2
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; CHECK-NEXT: ; %bb.1: ; %false
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; CHECK-NEXT: bl _baz
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; CHECK-NEXT: b LBB0_3
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; CHECK-NEXT: LBB0_2: ; %true
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; CHECK-NEXT: bl _bar
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; CHECK-NEXT: LBB0_3: ; %common.ret
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; CHECK-NEXT: add sp, sp, #1, lsl #12 ; =4096
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; CHECK-NEXT: add sp, sp, #80
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; CHECK-NEXT: ldp x29, x30, [sp, #16] ; 16-byte Folded Reload
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; CHECK-NEXT: ldp x28, x27, [sp], #32 ; 16-byte Folded Reload
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; CHECK-NEXT: ret
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%var = alloca i32, i32 12
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%var2 = alloca i32, i32 1030
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%tst = icmp eq ptr %var, null
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br i1 %tst, label %true, label %false
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true:
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call void @bar()
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ret void
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false:
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call void @baz()
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ret void
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}
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declare void @bar()
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declare void @baz()
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