85c53c7092
It caused builds to assert with: (StackSize == 0 && "We already have the CFA offset!"), function generateCompactUnwindEncoding, file AArch64AsmBackend.cpp, line 624. when targeting iOS. See comment on the code review for reproducer. > 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 This reverts commit 32e8b550e5439c7e4aafa73894faffd5f25d0d05.
124 lines
4.5 KiB
LLVM
124 lines
4.5 KiB
LLVM
; RUN: split-file %s %t
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; RUN: cat %t/main.ll %t/a.ll > %t/a2.ll
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; RUN: cat %t/main.ll %t/b.ll > %t/b2.ll
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; RUN: cat %t/main.ll %t/c.ll > %t/c2.ll
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; RUN: cat %t/main.ll %t/d.ll > %t/d2.ll
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; RUN: cat %t/main.ll %t/e.ll > %t/e2.ll
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; RUN: cat %t/main.ll %t/f.ll > %t/f2.ll
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; RUN: cat %t/main.ll %t/g.ll > %t/g2.ll
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; RUN: cat %t/main.ll %t/h.ll > %t/h2.ll
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; RUN: cat %t/main.ll %t/i.ll > %t/i2.ll
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; RUN: cat %t/main.ll %t/j.ll > %t/j2.ll
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; RUN: llc %t/a2.ll -verify-machineinstrs -o - | \
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; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NO-OFFSET %s
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; RUN: llc %t/b2.ll -verify-machineinstrs -o - | \
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; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-POSITIVE-OFFSET %s
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; RUN: llc %t/c2.ll -verify-machineinstrs -o - | \
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; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NEGATIVE-OFFSET %s
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; RUN: llc %t/d2.ll -verify-machineinstrs -o - | \
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; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NPOT-OFFSET %s
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; RUN: llc %t/e2.ll -verify-machineinstrs -o - | \
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; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NPOT-NEG-OFFSET %s
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; RUN: llc %t/f2.ll -verify-machineinstrs -o - | \
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; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-257-OFFSET %s
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; RUN: llc %t/g2.ll -verify-machineinstrs -o - | \
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; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-MINUS-257-OFFSET %s
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; XFAIL
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; RUN: not --crash llc %t/h2.ll -o - 2>&1 | \
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; RUN: FileCheck --check-prefix=CHECK-BAD-OFFSET %s
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; RUN: not --crash llc %t/i2.ll -o - 2>&1 | \
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; RUN: FileCheck --check-prefix=CHECK-BAD-OFFSET %s
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; RUN: not --crash llc %t/j2.ll -o - 2>&1 | \
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; RUN: FileCheck --check-prefix=CHECK-BAD-OFFSET %s
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;--- main.ll
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target triple = "aarch64-unknown-linux-gnu"
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; Verify that we `mrs` from `SP_EL0` twice, rather than load from
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; __stack_chk_guard.
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define dso_local void @foo(i64 %t) local_unnamed_addr #0 {
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; CHECK-LABEL: foo:
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; CHECK: // %bb.0: // %entry
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; CHECK-NEXT: stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
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; CHECK-NEXT: mov x29, sp
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; CHECK-NEXT: sub sp, sp, #16
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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: mrs x8, SP_EL0
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; CHECK-NEXT: lsl x9, x0, #2
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; CHECK-NO-OFFSET: ldr x8, [x8]
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; CHECK-POSITIVE-OFFSET: ldr x8, [x8, #8]
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; CHECK-NEGATIVE-OFFSET: ldur x8, [x8, #-8]
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; CHECK-NPOT-OFFSET: ldur x8, [x8, #1]
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; CHECK-NPOT-NEG-OFFSET: ldur x8, [x8, #-1]
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; CHECK-257-OFFSET: add x8, x8, #257
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; CHECK-MINUS-257-OFFSET: sub x8, x8, #257
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; CHECK-NEXT: add x9, x9, #15
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; CHECK-NEXT: and x9, x9, #0xfffffffffffffff0
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; CHECK-257-OFFSET-NEXT: ldr x8, [x8]
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; CHECK-MINUS-257-OFFSET-NEXT: ldr x8, [x8]
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; CHECK-NEXT: stur x8, [x29, #-8]
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; CHECK-NEXT: mov x8, sp
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; CHECK-NEXT: sub x0, x8, x9
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; CHECK-NEXT: mov sp, x0
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; CHECK-NEXT: bl baz
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; CHECK-NEXT: mrs x8, SP_EL0
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; CHECK-NO-OFFSET: ldr x8, [x8]
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; CHECK-POSITIVE-OFFSET: ldr x8, [x8, #8]
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; CHECK-NEGATIVE-OFFSET: ldur x8, [x8, #-8]
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; CHECK-NPOT-OFFSET: ldur x8, [x8, #1]
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; CHECK-NPOT-NEG-OFFSET: ldur x8, [x8, #-1]
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; CHECK-257-OFFSET: add x8, x8, #257
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; CHECK-257-OFFSET-NEXT: ldr x8, [x8]
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; CHECK-MINUS-257-OFFSET: sub x8, x8, #257
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; CHECK-MINUS-257-OFFSET-NEXT: ldr x8, [x8]
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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: mov sp, x29
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; CHECK-NEXT: ldp x29, x30, [sp], #16 // 16-byte Folded Reload
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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-NOT: __stack_chk_guard
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entry:
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%vla = alloca i32, i64 %t, align 4
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call void @baz(i32* nonnull %vla)
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ret void
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}
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declare void @baz(i32*)
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; CHECK-BAD-OFFSET: LLVM ERROR: Unable to encode Stack Protector Guard Offset
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attributes #0 = { sspstrong }
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!llvm.module.flags = !{!1, !2, !3}
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!1 = !{i32 2, !"stack-protector-guard", !"sysreg"}
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!2 = !{i32 2, !"stack-protector-guard-reg", !"sp_el0"}
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;--- a.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 0}
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;--- b.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 8}
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;--- c.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 -8}
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;--- d.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 1}
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;--- e.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 -1}
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;--- f.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 257}
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;--- g.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 -257}
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;--- h.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 32761}
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;--- i.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 -4096}
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;--- j.ll
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!3 = !{i32 2, !"stack-protector-guard-offset", i32 4097}
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