1 //===------- X86ExpandPseudo.cpp - Expand pseudo instructions -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains a pass that expands pseudo instructions into target
11 // instructions to allow proper scheduling, if-conversion, other late
12 // optimizations, or simply the encoding of the instructions.
14 //===----------------------------------------------------------------------===//
17 #include "X86FrameLowering.h"
18 #include "X86InstrBuilder.h"
19 #include "X86InstrInfo.h"
20 #include "X86MachineFunctionInfo.h"
21 #include "X86Subtarget.h"
22 #include "llvm/CodeGen/Passes.h" // For IDs of passes that are preserved.
23 #include "llvm/CodeGen/MachineFunctionPass.h"
24 #include "llvm/CodeGen/MachineInstrBuilder.h"
25 #include "llvm/IR/GlobalValue.h"
28 #define DEBUG_TYPE "x86-pseudo"
31 class X86ExpandPseudo : public MachineFunctionPass {
34 X86ExpandPseudo() : MachineFunctionPass(ID) {}
36 void getAnalysisUsage(AnalysisUsage &AU) const override {
38 AU.addPreservedID(MachineLoopInfoID);
39 AU.addPreservedID(MachineDominatorsID);
40 MachineFunctionPass::getAnalysisUsage(AU);
43 const X86Subtarget *STI;
44 const X86InstrInfo *TII;
45 const X86RegisterInfo *TRI;
46 const X86FrameLowering *X86FL;
48 bool runOnMachineFunction(MachineFunction &Fn) override;
50 const char *getPassName() const override {
51 return "X86 pseudo instruction expansion pass";
55 bool ExpandMI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI);
56 bool ExpandMBB(MachineBasicBlock &MBB);
58 char X86ExpandPseudo::ID = 0;
59 } // End anonymous namespace.
61 /// If \p MBBI is a pseudo instruction, this method expands
62 /// it to the corresponding (sequence of) actual instruction(s).
63 /// \returns true if \p MBBI has been expanded.
64 bool X86ExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
65 MachineBasicBlock::iterator MBBI) {
66 MachineInstr &MI = *MBBI;
67 unsigned Opcode = MI.getOpcode();
68 DebugLoc DL = MBBI->getDebugLoc();
75 case X86::TCRETURNdi64:
76 case X86::TCRETURNri64:
77 case X86::TCRETURNmi64: {
78 bool isMem = Opcode == X86::TCRETURNmi || Opcode == X86::TCRETURNmi64;
79 MachineOperand &JumpTarget = MBBI->getOperand(0);
80 MachineOperand &StackAdjust = MBBI->getOperand(isMem ? 5 : 1);
81 assert(StackAdjust.isImm() && "Expecting immediate value.");
83 // Adjust stack pointer.
84 int StackAdj = StackAdjust.getImm();
87 // Check for possible merge with preceding ADD instruction.
88 StackAdj += X86FL->mergeSPUpdates(MBB, MBBI, true);
89 X86FL->emitSPUpdate(MBB, MBBI, StackAdj, /*InEpilogue=*/true);
92 // Jump to label or value in register.
93 bool IsWin64 = STI->isTargetWin64();
94 if (Opcode == X86::TCRETURNdi || Opcode == X86::TCRETURNdi64) {
95 unsigned Op = (Opcode == X86::TCRETURNdi)
97 : (IsWin64 ? X86::TAILJMPd64_REX : X86::TAILJMPd64);
98 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII->get(Op));
99 if (JumpTarget.isGlobal())
100 MIB.addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
101 JumpTarget.getTargetFlags());
103 assert(JumpTarget.isSymbol());
104 MIB.addExternalSymbol(JumpTarget.getSymbolName(),
105 JumpTarget.getTargetFlags());
107 } else if (Opcode == X86::TCRETURNmi || Opcode == X86::TCRETURNmi64) {
108 unsigned Op = (Opcode == X86::TCRETURNmi)
110 : (IsWin64 ? X86::TAILJMPm64_REX : X86::TAILJMPm64);
111 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII->get(Op));
112 for (unsigned i = 0; i != 5; ++i)
113 MIB.addOperand(MBBI->getOperand(i));
114 } else if (Opcode == X86::TCRETURNri64) {
115 BuildMI(MBB, MBBI, DL,
116 TII->get(IsWin64 ? X86::TAILJMPr64_REX : X86::TAILJMPr64))
117 .addReg(JumpTarget.getReg(), RegState::Kill);
119 BuildMI(MBB, MBBI, DL, TII->get(X86::TAILJMPr))
120 .addReg(JumpTarget.getReg(), RegState::Kill);
123 MachineInstr *NewMI = std::prev(MBBI);
124 NewMI->copyImplicitOps(*MBBI->getParent()->getParent(), MBBI);
126 // Delete the pseudo instruction TCRETURN.
132 case X86::EH_RETURN64: {
133 MachineOperand &DestAddr = MBBI->getOperand(0);
134 assert(DestAddr.isReg() && "Offset should be in register!");
135 const bool Uses64BitFramePtr =
136 STI->isTarget64BitLP64() || STI->isTargetNaCl64();
137 unsigned StackPtr = TRI->getStackRegister();
138 BuildMI(MBB, MBBI, DL,
139 TII->get(Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr), StackPtr)
140 .addReg(DestAddr.getReg());
141 // The EH_RETURN pseudo is really removed during the MC Lowering.
145 llvm_unreachable("Previous switch has a fallthrough?");
148 /// Expand all pseudo instructions contained in \p MBB.
149 /// \returns true if any expansion occurred for \p MBB.
150 bool X86ExpandPseudo::ExpandMBB(MachineBasicBlock &MBB) {
151 bool Modified = false;
153 // MBBI may be invalidated by the expansion.
154 MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
156 MachineBasicBlock::iterator NMBBI = std::next(MBBI);
157 Modified |= ExpandMI(MBB, MBBI);
164 bool X86ExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
165 STI = &static_cast<const X86Subtarget &>(MF.getSubtarget());
166 TII = STI->getInstrInfo();
167 TRI = STI->getRegisterInfo();
168 X86FL = STI->getFrameLowering();
170 bool Modified = false;
171 for (MachineBasicBlock &MBB : MF)
172 Modified |= ExpandMBB(MBB);
176 /// Returns an instance of the pseudo instruction expansion pass.
177 FunctionPass *llvm::createX86ExpandPseudoPass() {
178 return new X86ExpandPseudo();