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__anon74989e0d0111::PPCTLSDynamicCall45 PPCTLSDynamicCall() : MachineFunctionPass(ID) {
46 initializePPCTLSDynamicCallPass(*PassRegistry::getPassRegistry());
47 }
48
49 const PPCInstrInfo *TII;
50 LiveIntervals *LIS;
51
52 protected:
processBlock__anon74989e0d0111::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;) {
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 ++I;
66 continue;
67 }
68
69 DEBUG(dbgs() << "TLS Dynamic Call Fixup:\n " << *MI;);
70
71 unsigned OutReg = MI->getOperand(0).getReg();
72 unsigned InReg = MI->getOperand(1).getReg();
73 DebugLoc DL = MI->getDebugLoc();
74 unsigned GPR3 = Is64Bit ? PPC::X3 : PPC::R3;
75 unsigned Opc1, Opc2;
76 const unsigned OrigRegs[] = {OutReg, InReg, GPR3};
77
78 switch (MI->getOpcode()) {
79 default:
80 llvm_unreachable("Opcode inconsistency error");
81 case PPC::ADDItlsgdLADDR:
82 Opc1 = PPC::ADDItlsgdL;
83 Opc2 = PPC::GETtlsADDR;
84 break;
85 case PPC::ADDItlsldLADDR:
86 Opc1 = PPC::ADDItlsldL;
87 Opc2 = PPC::GETtlsldADDR;
88 break;
89 case PPC::ADDItlsgdLADDR32:
90 Opc1 = PPC::ADDItlsgdL32;
91 Opc2 = PPC::GETtlsADDR32;
92 break;
93 case PPC::ADDItlsldLADDR32:
94 Opc1 = PPC::ADDItlsldL32;
95 Opc2 = PPC::GETtlsldADDR32;
96 break;
97 }
98
99 // Don't really need to save data to the stack - the clobbered
100 // registers are already saved when the SDNode (e.g. PPCaddiTlsgdLAddr)
101 // gets translated to the pseudo instruction (e.g. ADDItlsgdLADDR).
102 BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKDOWN)).addImm(0);
103
104 // Expand into two ops built prior to the existing instruction.
105 MachineInstr *Addi = BuildMI(MBB, I, DL, TII->get(Opc1), GPR3)
106 .addReg(InReg);
107 Addi->addOperand(MI->getOperand(2));
108
109 // The ADDItls* instruction is the first instruction in the
110 // repair range.
111 MachineBasicBlock::iterator First = I;
112 --First;
113
114 MachineInstr *Call = (BuildMI(MBB, I, DL, TII->get(Opc2), GPR3)
115 .addReg(GPR3));
116 Call->addOperand(MI->getOperand(3));
117
118 BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKUP)).addImm(0).addImm(0);
119
120 BuildMI(MBB, I, DL, TII->get(TargetOpcode::COPY), OutReg)
121 .addReg(GPR3);
122
123 // The COPY is the last instruction in the repair range.
124 MachineBasicBlock::iterator Last = I;
125 --Last;
126
127 // Move past the original instruction and remove it.
128 ++I;
129 MI->removeFromParent();
130
131 // Repair the live intervals.
132 LIS->repairIntervalsInRange(&MBB, First, Last, OrigRegs);
133 Changed = true;
134 }
135
136 return Changed;
137 }
138
139 public:
runOnMachineFunction__anon74989e0d0111::PPCTLSDynamicCall140 bool runOnMachineFunction(MachineFunction &MF) override {
141 TII = MF.getSubtarget<PPCSubtarget>().getInstrInfo();
142 LIS = &getAnalysis<LiveIntervals>();
143
144 bool Changed = false;
145
146 for (MachineFunction::iterator I = MF.begin(); I != MF.end();) {
147 MachineBasicBlock &B = *I++;
148 if (processBlock(B))
149 Changed = true;
150 }
151
152 return Changed;
153 }
154
getAnalysisUsage__anon74989e0d0111::PPCTLSDynamicCall155 void getAnalysisUsage(AnalysisUsage &AU) const override {
156 AU.addRequired<LiveIntervals>();
157 AU.addPreserved<LiveIntervals>();
158 AU.addRequired<SlotIndexes>();
159 AU.addPreserved<SlotIndexes>();
160 MachineFunctionPass::getAnalysisUsage(AU);
161 }
162 };
163 }
164
165 INITIALIZE_PASS_BEGIN(PPCTLSDynamicCall, DEBUG_TYPE,
166 "PowerPC TLS Dynamic Call Fixup", false, false)
167 INITIALIZE_PASS_DEPENDENCY(LiveIntervals)
168 INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
169 INITIALIZE_PASS_END(PPCTLSDynamicCall, DEBUG_TYPE,
170 "PowerPC TLS Dynamic Call Fixup", false, false)
171
172 char PPCTLSDynamicCall::ID = 0;
173 FunctionPass*
createPPCTLSDynamicCallPass()174 llvm::createPPCTLSDynamicCallPass() { return new PPCTLSDynamicCall(); }
175