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According to psABI, PLT stub clobbers XMM8-XMM15. In Regcall calling convention those registers are used for passing parameters. Thus we need to prevent lazy binding in Regcall. Differential Revision: https://reviews.llvm.org/D32430 llvm-svn: 302124
45 lines
1.5 KiB
LLVM
45 lines
1.5 KiB
LLVM
; RUN: llc -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic < %s | FileCheck %s
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; RUN: llc -mtriple=x86_64-freebsd -relocation-model=pic < %s | FileCheck %s
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; According to x86-64 psABI, xmm0-xmm7 can be used to pass function parameters.
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;; However regcall calling convention uses also xmm8-xmm15 to pass function
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;; parameters which violates x86-64 psABI.
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;; Detail info about it can be found at:
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;; https://sourceware.org/bugzilla/show_bug.cgi?id=21265
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;;
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;; We encounter the violation symptom when using PIC with lazy binding
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;; optimization.
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;; In that case the PLT mechanism as described in x86_64 psABI will
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;; not preserve xmm8-xmm15 registers and will lead to miscompilation.
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;;
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;; The agreed solution is to disable PLT for regcall calling convention for
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;; SystemV using ELF format.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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declare void @lazy()
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declare x86_regcallcc void @regcall_not_lazy()
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; CHECK-LABEL: foo:
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; CHECK: callq lazy@PLT
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; CHECK: callq *regcall_not_lazy@GOTPCREL(%rip)
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define void @foo() nounwind {
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call void @lazy()
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call void @regcall_not_lazy()
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ret void
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}
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; CHECK-LABEL: tail_call_regcall:
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; CHECK: jmpq *regcall_not_lazy@GOTPCREL(%rip)
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define void @tail_call_regcall() nounwind {
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tail call void @regcall_not_lazy()
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ret void
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}
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; CHECK-LABEL: tail_call_regular:
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; CHECK: jmp lazy
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define void @tail_call_regular() nounwind {
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tail call void @lazy()
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ret void
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}
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