1 ; RUN: llc -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic < %s | FileCheck %s 2 ; RUN: llc -mtriple=x86_64-freebsd -relocation-model=pic < %s | FileCheck %s 3 4 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 5 ;; According to x86-64 psABI, xmm0-xmm7 can be used to pass function parameters. 6 ;; However regcall calling convention uses also xmm8-xmm15 to pass function 7 ;; parameters which violates x86-64 psABI. 8 ;; Detail info about it can be found at: 9 ;; https://sourceware.org/bugzilla/show_bug.cgi?id=21265 10 ;; 11 ;; We encounter the violation symptom when using PIC with lazy binding 12 ;; optimization. 13 ;; In that case the PLT mechanism as described in x86_64 psABI will 14 ;; not preserve xmm8-xmm15 registers and will lead to miscompilation. 15 ;; 16 ;; The agreed solution is to disable PLT for regcall calling convention for 17 ;; SystemV using ELF format. 18 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 19 20 declare void @lazy() 21 declare x86_regcallcc void @regcall_not_lazy() 22 23 ; CHECK-LABEL: foo: 24 ; CHECK: callq lazy@PLT 25 ; CHECK: callq *regcall_not_lazy@GOTPCREL(%rip) 26 define void @foo() nounwind { 27 call void @lazy() 28 call void @regcall_not_lazy() 29 ret void 30 } 31 32 ; CHECK-LABEL: tail_call_regcall: 33 ; CHECK: jmpq *regcall_not_lazy@GOTPCREL(%rip) 34 define void @tail_call_regcall() nounwind { 35 tail call void @regcall_not_lazy() 36 ret void 37 } 38 39 ; CHECK-LABEL: tail_call_regular: 40 ; CHECK: jmp lazy 41 define void @tail_call_regular() nounwind { 42 tail call void @lazy() 43 ret void 44 } 45
