1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-24 13:33:37 +02:00
llvm-mirror/test/CodeGen/AArch64/xray-tail-call-sled.ll
Dean Michael Berris 04bb923d73 [XRay] Reduce synthetic references emitted by XRay
Summary:
When we're building with XRay instrumentation, we use a trick that
preserves references from the function to a function sled index. This
index table lives in a separate section, and without this trick the
linker is free to garbage-collect this section and all the segments it
refers to. Until we're able to tell the linkers to preserve these
sections, we use this reference trick to keep around both the index and
the entries in the instrumentation map.

Before this change we emitted both a synthetic reference to the label in
the instrumentation map, and to the entry in the function map index.
This change removes the first synthetic reference and only emits one
synthetic reference to the index -- the index entry has the references
to the labels in the instrumentation map, so the linker will still
preserve those if the function itself is preserved.

This reduces the amount of synthetic references we emit from 16 bytes to
just 8 bytes in x86_64, and similarly to other platforms.

Reviewers: dblaikie

Subscribers: javed.absar, kpw, pelikan, llvm-commits

Differential Revision: https://reviews.llvm.org/D34340

llvm-svn: 305880
2017-06-21 06:39:42 +00:00

80 lines
2.2 KiB
LLVM

; RUN: llc -filetype=asm -o - -mtriple=aarch64-linux-gnu < %s | FileCheck %s
define i32 @callee() nounwind noinline uwtable "function-instrument"="xray-always" {
; CHECK: .p2align 2
; CHECK-LABEL: .Lxray_sled_0:
; CHECK-NEXT: b #32
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: .Ltmp0:
ret i32 0
; CHECK-NEXT: mov w0, wzr
; CHECK-NEXT: .p2align 2
; CHECK-LABEL: .Lxray_sled_1:
; CHECK-NEXT: b #32
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: .Ltmp1:
; CHECK-NEXT: ret
}
; CHECK: .p2align 4
; CHECK-NEXT: .xword .Lxray_fn_idx_synth_0
; CHECK-NEXT: .section xray_instr_map,{{.*}}
; CHECK-LABEL: Lxray_sleds_start0:
; CHECK: .xword .Lxray_sled_0
; CHECK: .xword .Lxray_sled_1
; CHECK-LABEL: Lxray_sleds_end0:
; CHECK: .section xray_fn_idx,{{.*}}
; CHECK-LABEL: Lxray_fn_idx_synth_0:
; CHECK: .xword .Lxray_sleds_start0
; CHECK-NEXT: .xword .Lxray_sleds_end0
define i32 @caller() nounwind noinline uwtable "function-instrument"="xray-always" {
; CHECK: .p2align 2
; CHECK-LABEL: Lxray_sled_2:
; CHECK-NEXT: b #32
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: .Ltmp2:
; CHECK: .p2align 2
; CHECK-LABEL: Lxray_sled_3:
; CHECK-NEXT: b #32
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-NEXT: nop
; CHECK-LABEL: .Ltmp3:
%retval = tail call i32 @callee()
; CHECK: b callee
ret i32 %retval
}
; CHECK: .p2align 4
; CHECK-NEXT: .xword .Lxray_fn_idx_synth_1
; CHECK-NEXT: .section xray_instr_map,{{.*}}
; CHECK-LABEL: Lxray_sleds_start1:
; CHECK: .xword .Lxray_sled_2
; CHECK: .xword .Lxray_sled_3
; CHECK-LABEL: Lxray_sleds_end1:
; CHECK: .section xray_fn_idx,{{.*}}
; CHECK-LABEL: Lxray_fn_idx_synth_1:
; CHECK: .xword .Lxray_sleds_start1
; CHECK-NEXT: .xword .Lxray_sleds_end1