From a580b6ec67ec605f563bc4e52a3490b9c951ce59 Mon Sep 17 00:00:00 2001 From: Reid Kleckner Date: Fri, 30 Jan 2015 21:03:31 +0000 Subject: Win64: Put a REX_W prefix on all TAILJMP* instructions MSDN's x64 software conventions page says that this is one of the fixed list of legal epilogues: https://msdn.microsoft.com/en-us/library/tawsa7cb.aspx Presumably this is how the unwinder distinguishes epilogue jumps from in-function control flow. Also normalize the way we place "## TAILCALL" comments on such jumps. llvm-svn: 227611 --- llvm/lib/Target/X86/X86FrameLowering.cpp | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'llvm/lib/Target/X86/X86FrameLowering.cpp') diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp index f64e5d45dfb..930163c3688 100644 --- a/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -1123,10 +1123,12 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, } // Jump to label or value in register. + bool IsWin64 = STI.isTargetWin64(); if (RetOpcode == X86::TCRETURNdi || RetOpcode == X86::TCRETURNdi64) { - MachineInstrBuilder MIB = - BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNdi) - ? X86::TAILJMPd : X86::TAILJMPd64)); + unsigned Op = (RetOpcode == X86::TCRETURNdi) + ? X86::TAILJMPd + : (IsWin64 ? X86::TAILJMPd64_REX : X86::TAILJMPd64); + MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII.get(Op)); if (JumpTarget.isGlobal()) MIB.addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(), JumpTarget.getTargetFlags()); @@ -1136,14 +1138,16 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, JumpTarget.getTargetFlags()); } } else if (RetOpcode == X86::TCRETURNmi || RetOpcode == X86::TCRETURNmi64) { - MachineInstrBuilder MIB = - BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNmi) - ? X86::TAILJMPm : X86::TAILJMPm64)); + unsigned Op = (RetOpcode == X86::TCRETURNmi) + ? X86::TAILJMPm + : (IsWin64 ? X86::TAILJMPm64_REX : X86::TAILJMPm64); + MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII.get(Op)); for (unsigned i = 0; i != 5; ++i) MIB.addOperand(MBBI->getOperand(i)); } else if (RetOpcode == X86::TCRETURNri64) { - BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr64)). - addReg(JumpTarget.getReg(), RegState::Kill); + BuildMI(MBB, MBBI, DL, + TII.get(IsWin64 ? X86::TAILJMPr64_REX : X86::TAILJMPr64)) + .addReg(JumpTarget.getReg(), RegState::Kill); } else { BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr)). addReg(JumpTarget.getReg(), RegState::Kill); -- cgit v1.2.3