1 //===---------- PPCTLSDynamicCall.cpp - TLS Dynamic Call Fixup ------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This pass expands ADDItls{ld,gd}LADDR[32] machine instructions into
11 // separate ADDItls[gd]L[32] and GETtlsADDR[32] instructions, both of
12 // which define GPR3. A copy is added from GPR3 to the target virtual
13 // register of the original instruction. The GETtlsADDR[32] is really
14 // a call instruction, so its target register is constrained to be GPR3.
15 // This is not true of ADDItls[gd]L[32], but there is a legacy linker
16 // optimization bug that requires the target register of the addi of
17 // a local- or general-dynamic TLS access sequence to be GPR3.
18 //
19 // This is done in a late pass so that TLS variable accesses can be
20 // fully commoned by MachineCSE.
21 //
22 //===----------------------------------------------------------------------===//
23
24 #include "PPCInstrInfo.h"
25 #include "PPC.h"
26 #include "PPCInstrBuilder.h"
27 #include "PPCTargetMachine.h"
28 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
29 #include "llvm/CodeGen/MachineFunctionPass.h"
30 #include "llvm/CodeGen/MachineInstrBuilder.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/raw_ostream.h"
33
34 using namespace llvm;
35
36 #define DEBUG_TYPE "ppc-tls-dynamic-call"
37
38 namespace llvm {
39 void initializePPCTLSDynamicCallPass(PassRegistry&);
40 }
41
42 namespace {
43 struct PPCTLSDynamicCall : public MachineFunctionPass {
44 static char ID;
PPCTLSDynamicCall__anon144f50ce0111::PPCTLSDynamicCall45 PPCTLSDynamicCall() : MachineFunctionPass(ID) {
46 initializePPCTLSDynamicCallPass(*PassRegistry::getPassRegistry());
47 }
48
49 const PPCInstrInfo *TII;
50 LiveIntervals *LIS;
51
52 protected:
processBlock__anon144f50ce0111::PPCTLSDynamicCall53 bool processBlock(MachineBasicBlock &MBB) {
54 bool Changed = false;
55 bool Is64Bit = MBB.getParent()->getSubtarget<PPCSubtarget>().isPPC64();
56
57 for (MachineBasicBlock::iterator I = MBB.begin(), IE = MBB.end();
58 I != IE; ++I) {
59 MachineInstr *MI = I;
60
61 if (MI->getOpcode() != PPC::ADDItlsgdLADDR &&
62 MI->getOpcode() != PPC::ADDItlsldLADDR &&
63 MI->getOpcode() != PPC::ADDItlsgdLADDR32 &&
64 MI->getOpcode() != PPC::ADDItlsldLADDR32)
65 continue;
66
67 DEBUG(dbgs() << "TLS Dynamic Call Fixup:\n " << *MI;);
68
69 unsigned OutReg = MI->getOperand(0).getReg();
70 unsigned InReg = MI->getOperand(1).getReg();
71 DebugLoc DL = MI->getDebugLoc();
72 unsigned GPR3 = Is64Bit ? PPC::X3 : PPC::R3;
73 unsigned Opc1, Opc2;
74 SmallVector<unsigned, 4> OrigRegs;
75 OrigRegs.push_back(OutReg);
76 OrigRegs.push_back(InReg);
77 OrigRegs.push_back(GPR3);
78
79 switch (MI->getOpcode()) {
80 default:
81 llvm_unreachable("Opcode inconsistency error");
82 case PPC::ADDItlsgdLADDR:
83 Opc1 = PPC::ADDItlsgdL;
84 Opc2 = PPC::GETtlsADDR;
85 break;
86 case PPC::ADDItlsldLADDR:
87 Opc1 = PPC::ADDItlsldL;
88 Opc2 = PPC::GETtlsldADDR;
89 break;
90 case PPC::ADDItlsgdLADDR32:
91 Opc1 = PPC::ADDItlsgdL32;
92 Opc2 = PPC::GETtlsADDR32;
93 break;
94 case PPC::ADDItlsldLADDR32:
95 Opc1 = PPC::ADDItlsldL32;
96 Opc2 = PPC::GETtlsldADDR32;
97 break;
98 }
99
100 // Expand into two ops built prior to the existing instruction.
101 MachineInstr *Addi = BuildMI(MBB, I, DL, TII->get(Opc1), GPR3)
102 .addReg(InReg);
103 Addi->addOperand(MI->getOperand(2));
104
105 // The ADDItls* instruction is the first instruction in the
106 // repair range.
107 MachineBasicBlock::iterator First = I;
108 --First;
109
110 MachineInstr *Call = (BuildMI(MBB, I, DL, TII->get(Opc2), GPR3)
111 .addReg(GPR3));
112 Call->addOperand(MI->getOperand(3));
113
114 BuildMI(MBB, I, DL, TII->get(TargetOpcode::COPY), OutReg)
115 .addReg(GPR3);
116
117 // The COPY is the last instruction in the repair range.
118 MachineBasicBlock::iterator Last = I;
119 --Last;
120
121 // Move past the original instruction and remove it.
122 ++I;
123 MI->removeFromParent();
124
125 // Repair the live intervals.
126 LIS->repairIntervalsInRange(&MBB, First, Last, OrigRegs);
127 Changed = true;
128 }
129
130 return Changed;
131 }
132
133 public:
runOnMachineFunction__anon144f50ce0111::PPCTLSDynamicCall134 bool runOnMachineFunction(MachineFunction &MF) override {
135 TII = MF.getSubtarget<PPCSubtarget>().getInstrInfo();
136 LIS = &getAnalysis<LiveIntervals>();
137
138 bool Changed = false;
139
140 for (MachineFunction::iterator I = MF.begin(); I != MF.end();) {
141 MachineBasicBlock &B = *I++;
142 if (processBlock(B))
143 Changed = true;
144 }
145
146 return Changed;
147 }
148
getAnalysisUsage__anon144f50ce0111::PPCTLSDynamicCall149 void getAnalysisUsage(AnalysisUsage &AU) const override {
150 AU.addRequired<LiveIntervals>();
151 AU.addPreserved<LiveIntervals>();
152 AU.addRequired<SlotIndexes>();
153 AU.addPreserved<SlotIndexes>();
154 MachineFunctionPass::getAnalysisUsage(AU);
155 }
156 };
157 }
158
159 INITIALIZE_PASS_BEGIN(PPCTLSDynamicCall, DEBUG_TYPE,
160 "PowerPC TLS Dynamic Call Fixup", false, false)
161 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
162 INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
163 INITIALIZE_PASS_END(PPCTLSDynamicCall, DEBUG_TYPE,
164 "PowerPC TLS Dynamic Call Fixup", false, false)
165
166 char PPCTLSDynamicCall::ID = 0;
167 FunctionPass*
createPPCTLSDynamicCallPass()168 llvm::createPPCTLSDynamicCallPass() { return new PPCTLSDynamicCall(); }
169