forked from OSchip/llvm-project
38 lines
1.7 KiB
LLVM
38 lines
1.7 KiB
LLVM
; RUN: llc < %s -relocation-model=pic -O2 -frame-pointer=all -o - | FileCheck %s
|
|
; RUN: llc < %s -relocation-model=pic -O2 -o - | FileCheck %s
|
|
|
|
; This test runs twice with different options regarding the frame pointer:
|
|
; first the elimination is disabled, then it is enabled. The disabled case is
|
|
; the "control group".
|
|
; The function 'foo' below is marked with the "no-frame-pointer-elim-non-leaf"
|
|
; attribute which dictates that the frame pointer should not be eliminated
|
|
; unless the function is a leaf (i.e. it doesn't call any other function).
|
|
; Now, 'foo' is not a leaf function, because it performs a TLS access which on
|
|
; X86 ELF in PIC mode is expanded as a library call.
|
|
; This call is represented with a pseudo-instruction which doesn't appear to be
|
|
; a call when inspected by the analysis passes (it doesn't have the "isCall"
|
|
; flag), and the ISel lowering code creating the pseudo was not informing the
|
|
; MachineFrameInfo that the function contained calls. This affected the decision
|
|
; whether to eliminate the frame pointer.
|
|
; With the fix, the "hasCalls" flag is set in the MFI for the function whenever
|
|
; a TLS access pseudo-instruction is created, so 'foo' appears to be a non-leaf
|
|
; function, and the difference in the options does not affect codegen: both
|
|
; versions will have a frame pointer.
|
|
|
|
; Test that there's some frame pointer usage in 'foo'...
|
|
; CHECK: foo:
|
|
; CHECK: pushq %rbp
|
|
; CHECK: movq %rsp, %rbp
|
|
; ... and the TLS library call is also present.
|
|
; CHECK: leaq x@TLSGD(%rip), %rdi
|
|
; CHECK: callq __tls_get_addr@PLT
|
|
|
|
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
|
|
target triple = "x86_64-unknown-linux-gnu"
|
|
|
|
@x = thread_local global i32 0
|
|
define i32 @foo() "no-frame-pointer-elim-non-leaf" {
|
|
%a = load i32, i32* @x, align 4
|
|
ret i32 %a
|
|
}
|