50a97aacac
Re-commit of 32e8b550e5
This patch rearranges emission of CFI instructions, so the resulting
DWARF and `.eh_frame` information is precise at every instruction.
The current state is that the unwind info is emitted only after the
function prologue. This is fine for synchronous (e.g. C++) exceptions,
but the information is generally incorrect when the program counter is
at an instruction in the prologue or the epilogue, for example:
```
stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
mov x29, sp
.cfi_def_cfa w29, 16
...
```
after the `stp` is executed the (initial) rule for the CFA still says
the CFA is in the `sp`, even though it's already offset by 16 bytes
A correct unwind info could look like:
```
stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
.cfi_def_cfa_offset 16
mov x29, sp
.cfi_def_cfa w29, 16
...
```
Having this information precise up to an instruction is useful for
sampling profilers that would like to get a stack backtrace. The end
goal (towards this patch is just a step) is to have fully working
`-fasynchronous-unwind-tables`.
Reviewed By: danielkiss, MaskRay
Differential Revision: https://reviews.llvm.org/D111411
70 lines
3.4 KiB
LLVM
70 lines
3.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc %s -o - -mtriple=aarch64-arm-none-eabi -O2 -mattr=+mops | FileCheck %s --check-prefix=CHECK-MOPS
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declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1 immarg)
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declare void @fn(i8*, i8*)
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define void @consecutive() {
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; CHECK-MOPS-LABEL: consecutive:
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; CHECK-MOPS: // %bb.0: // %entry
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; CHECK-MOPS-NEXT: stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
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; CHECK-MOPS-NEXT: .cfi_def_cfa_offset 16
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; CHECK-MOPS-NEXT: .cfi_offset w30, -8
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; CHECK-MOPS-NEXT: .cfi_offset w29, -16
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; CHECK-MOPS-NEXT: sub sp, sp, #2016
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; CHECK-MOPS-NEXT: .cfi_def_cfa_offset 2032
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; CHECK-MOPS-NEXT: mov w8, #1000
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; CHECK-MOPS-NEXT: add x9, sp, #8
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; CHECK-MOPS-NEXT: adrp x10, .LCPI0_0
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; CHECK-MOPS-NEXT: adrp x11, .LCPI0_1
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; CHECK-MOPS-NEXT: mov w12, #6424
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; CHECK-MOPS-NEXT: mov w13, #7452
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; CHECK-MOPS-NEXT: setp [x9]!, x8!, xzr
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; CHECK-MOPS-NEXT: setm [x9]!, x8!, xzr
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; CHECK-MOPS-NEXT: sete [x9]!, x8!, xzr
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; CHECK-MOPS-NEXT: movk w12, #6938, lsl #16
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; CHECK-MOPS-NEXT: ldr q0, [x10, :lo12:.LCPI0_0]
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; CHECK-MOPS-NEXT: mov w8, #30
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; CHECK-MOPS-NEXT: ldr d1, [x11, :lo12:.LCPI0_1]
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; CHECK-MOPS-NEXT: add x0, sp, #1008
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; CHECK-MOPS-NEXT: add x1, sp, #8
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; CHECK-MOPS-NEXT: str w12, [sp, #1032]
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; CHECK-MOPS-NEXT: strh w13, [sp, #1036]
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; CHECK-MOPS-NEXT: str q0, [sp, #1008]
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; CHECK-MOPS-NEXT: str d1, [sp, #1024]
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; CHECK-MOPS-NEXT: strb w8, [sp, #1038]
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; CHECK-MOPS-NEXT: bl fn
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; CHECK-MOPS-NEXT: add sp, sp, #2016
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; CHECK-MOPS-NEXT: ldp x29, x30, [sp], #16 // 16-byte Folded Reload
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; CHECK-MOPS-NEXT: ret
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entry:
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%buf_from = alloca [1000 x i8], align 16
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%buf_to = alloca [1000 x i8], align 1
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%0 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 0
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%1 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_to, i64 0, i64 0
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call void @llvm.memset.p0i8.i64(i8* noundef nonnull align 1 dereferenceable(1000) %1, i8 0, i64 1000, i1 false)
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%2 = bitcast [1000 x i8]* %buf_from to <16 x i8>*
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store <16 x i8> <i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 9, i8 10, i8 11, i8 12, i8 13, i8 14, i8 15>, <16 x i8>* %2, align 16
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%arrayidx.16 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 16
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%3 = bitcast i8* %arrayidx.16 to <8 x i8>*
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store <8 x i8> <i8 16, i8 17, i8 18, i8 19, i8 20, i8 21, i8 22, i8 23>, <8 x i8>* %3, align 16
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%arrayidx.24 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 24
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store i8 24, i8* %arrayidx.24, align 8
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%arrayidx.25 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 25
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store i8 25, i8* %arrayidx.25, align 1
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%arrayidx.26 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 26
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store i8 26, i8* %arrayidx.26, align 2
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%arrayidx.27 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 27
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store i8 27, i8* %arrayidx.27, align 1
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%arrayidx.28 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 28
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store i8 28, i8* %arrayidx.28, align 4
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%arrayidx.29 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 29
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store i8 29, i8* %arrayidx.29, align 1
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%arrayidx.30 = getelementptr inbounds [1000 x i8], [1000 x i8]* %buf_from, i64 0, i64 30
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store i8 30, i8* %arrayidx.30, align 2
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call void @fn(i8* nonnull %0, i8* nonnull %1)
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ret void
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}
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