bef8294650
The `__DATA,xray_instr_map` section has label differences like
`.quad Lxray_sled_0-Ltmp0` that is represented as a pair of UNSIGNED and SUBTRACTOR relocations.
LLVM integrated assembler attempts to rewrite A-B into A-B'+offset where B' can
be included in the symbol table. B' is called an atom and should be a
non-temporary symbol in the same section. However, since `xray_instr_map` does
not define a non-temporary symbol, the SUBTRACTOR relocation will have no
associated symbol, and its `r_extern` value will be 0. Therefore, we will see
linker errors like:
error: SUBTRACTOR relocation must be extern at offset 0 of __DATA,xray_instr_map in a.o
To fix this issue, we need to define a non-temporary symbol in the section. We
can accomplish this by renaming `Lxray_sleds_start0` to `lxray_sleds_start0`
("L" to "l").
`lxray_sleds_start0` serves as the atom for this dead-strippable subsection.
With the `S_ATTR_LIVE_SUPPORT` attribute, `ld -dead_strip` will retain
subsections that reference live functions.
Special thanks to Oleksii Lozovskyi for reporting the issue and providing
initial analysis.
Differential Revision: https://reviews.llvm.org/D153239
80 lines
3.0 KiB
LLVM
80 lines
3.0 KiB
LLVM
; When logging arguments is specified, emit the entry sled accordingly.
|
|
|
|
; RUN: llc -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck %s --check-prefixes=CHECK,CHECK-LINUX
|
|
; RUN: llc -mtriple=x86_64-darwin-unknown < %s | FileCheck %s --check-prefixes=CHECK,CHECK-MACOS
|
|
|
|
define i32 @callee(i32 %arg) nounwind noinline uwtable "function-instrument"="xray-always" "xray-log-args"="1" {
|
|
ret i32 %arg
|
|
}
|
|
; CHECK-LABEL: callee:
|
|
; CHECK-NEXT: Lfunc_begin0:
|
|
|
|
; CHECK-LINUX-LABEL: .Lxray_sleds_start0:
|
|
; CHECK-LINUX-NEXT: [[TMP:.Ltmp[0-9]+]]:
|
|
; CHECK-LINUX-NEXT: .quad .Lxray_sled_0-[[TMP]]
|
|
; CHECK-LINUX-NEXT: .quad .Lfunc_begin0-([[TMP]]+8)
|
|
; CHECK-LINUX-NEXT: .byte 0x03
|
|
; CHECK-LINUX-NEXT: .byte 0x01
|
|
; CHECK-LINUX-NEXT: .byte 0x02
|
|
; CHECK-LINUX: .zero 13
|
|
; CHECK-LINUX: [[TMP:.Ltmp[0-9]+]]:
|
|
; CHECK-LINUX-NEXT: .quad .Lxray_sled_1-[[TMP]]
|
|
; CHECK-LINUX-NEXT: .quad .Lfunc_begin0-([[TMP]]+8)
|
|
; CHECK-LINUX-NEXT: .byte 0x01
|
|
; CHECK-LINUX-NEXT: .byte 0x01
|
|
; CHECK-LINUX-NEXT: .byte 0x02
|
|
; CHECK-LINUX: .zero 13
|
|
|
|
; CHECK-MACOS-LABEL: lxray_sleds_start0:
|
|
; CHECK-MACOS-NEXT: [[TMP:Ltmp[0-9]+]]:
|
|
; CHECK-MACOS-NEXT: .quad Lxray_sled_0-[[TMP]]
|
|
; CHECK-MACOS-NEXT: .quad Lfunc_begin0-([[TMP]]+8)
|
|
; CHECK-MACOS-NEXT: .byte 0x03
|
|
; CHECK-MACOS-NEXT: .byte 0x01
|
|
; CHECK-MACOS-NEXT: .byte 0x02
|
|
; CHECK-MACOS: .space 13
|
|
; CHECK-MACOS: [[TMP:Ltmp[0-9]+]]:
|
|
; CHECK-MACOS-NEXT: .quad Lxray_sled_1-[[TMP]]
|
|
; CHECK-MACOS-NEXT: .quad Lfunc_begin0-([[TMP]]+8)
|
|
; CHECK-MACOS-NEXT: .byte 0x01
|
|
; CHECK-MACOS-NEXT: .byte 0x01
|
|
; CHECK-MACOS-NEXT: .byte 0x02
|
|
; CHECK-MACOS: .space 13
|
|
|
|
define i32 @caller(i32 %arg) nounwind noinline uwtable "function-instrument"="xray-always" "xray-log-args"="1" {
|
|
%retval = tail call i32 @callee(i32 %arg)
|
|
ret i32 %retval
|
|
}
|
|
|
|
; CHECK-LINUX-LABEL: .Lxray_sleds_start1:
|
|
; CHECK-LINUX-NEXT: [[TMP:.Ltmp[0-9]+]]:
|
|
; CHECK-LINUX-NEXT: .quad .Lxray_sled_2-[[TMP]]
|
|
; CHECK-LINUX-NEXT: .quad .Lfunc_begin1-([[TMP]]+8)
|
|
; CHECK-LINUX-NEXT: .byte 0x03
|
|
; CHECK-LINUX-NEXT: .byte 0x01
|
|
; CHECK-LINUX-NEXT: .byte 0x02
|
|
; CHECK-LINUX: .zero 13
|
|
; CHECK-LINUX: [[TMP:.Ltmp[0-9]+]]:
|
|
; CHECK-LINUX-NEXT: .quad .Lxray_sled_3-[[TMP]]
|
|
; CHECK-LINUX-NEXT: .quad .Lfunc_begin1-([[TMP]]+8)
|
|
; CHECK-LINUX-NEXT: .byte 0x02
|
|
; CHECK-LINUX-NEXT: .byte 0x01
|
|
; CHECK-LINUX-NEXT: .byte 0x02
|
|
; CHECK-LINUX: .zero 13
|
|
|
|
; CHECK-MACOS-LABEL: lxray_sleds_start1:
|
|
; CHECK-MACOS-NEXT: [[TMP:Ltmp[0-9]+]]:
|
|
; CHECK-MACOS-NEXT: .quad Lxray_sled_2-[[TMP]]
|
|
; CHECK-MACOS-NEXT: .quad Lfunc_begin1-([[TMP]]+8)
|
|
; CHECK-MACOS-NEXT: .byte 0x03
|
|
; CHECK-MACOS-NEXT: .byte 0x01
|
|
; CHECK-MACOS-NEXT: .byte 0x02
|
|
; CHECK-MACOS: .space 13
|
|
; CHECK-MACOS: [[TMP:Ltmp[0-9]+]]:
|
|
; CHECK-MACOS-NEXT: .quad Lxray_sled_3-[[TMP]]
|
|
; CHECK-MACOS-NEXT: .quad Lfunc_begin1-([[TMP]]+8)
|
|
; CHECK-MACOS-NEXT: .byte 0x02
|
|
; CHECK-MACOS-NEXT: .byte 0x01
|
|
; CHECK-MACOS-NEXT: .byte 0x02
|
|
; CHECK-MACOS: .space 13
|