LLVM  4.0.0
PPCTLSDynamicCall.cpp
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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"
31 #include "llvm/Support/Debug.h"
33 
34 using namespace llvm;
35 
36 #define DEBUG_TYPE "ppc-tls-dynamic-call"
37 
38 namespace llvm {
40 }
41 
42 namespace {
43  struct PPCTLSDynamicCall : public MachineFunctionPass {
44  static char ID;
45  PPCTLSDynamicCall() : MachineFunctionPass(ID) {
47  }
48 
49  const PPCInstrInfo *TII;
50  LiveIntervals *LIS;
51 
52 protected:
53  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.
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.
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:
140  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 
155  void getAnalysisUsage(AnalysisUsage &AU) const override {
158  AU.addRequired<SlotIndexes>();
161  }
162  };
163 }
164 
165 INITIALIZE_PASS_BEGIN(PPCTLSDynamicCall, DEBUG_TYPE,
166  "PowerPC TLS Dynamic Call Fixup", false, false)
169 INITIALIZE_PASS_END(PPCTLSDynamicCall, DEBUG_TYPE,
170  "PowerPC TLS Dynamic Call Fixup", false, false)
171 
172 char PPCTLSDynamicCall::ID = 0;
174 llvm::createPPCTLSDynamicCallPass() { return new PPCTLSDynamicCall(); }
const MachineFunction * getParent() const
Return the MachineFunction containing this basic block.
AnalysisUsage & addPreserved()
Add the specified Pass class to the set of analyses preserved by this pass.
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
void initializePPCTLSDynamicCallPass(PassRegistry &)
INITIALIZE_PASS_BEGIN(PPCTLSDynamicCall, DEBUG_TYPE,"PowerPC TLS Dynamic Call Fixup", false, false) INITIALIZE_PASS_END(PPCTLSDynamicCall
A debug info location.
Definition: DebugLoc.h:34
FunctionPass * createPPCTLSDynamicCallPass()
AnalysisUsage & addRequired()
#define INITIALIZE_PASS_DEPENDENCY(depName)
Definition: PassSupport.h:53
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
const HexagonInstrInfo * TII
const MachineInstrBuilder & addImm(int64_t Val) const
Add a new immediate operand.
SlotIndexes pass.
Definition: SlotIndexes.h:323
MachineBasicBlock * MBB
static GCRegistry::Add< OcamlGC > B("ocaml","ocaml 3.10-compatible GC")
unsigned getOpcode() const
Returns the opcode of this MachineInstr.
Definition: MachineInstr.h:273
PowerPC TLS Dynamic Call false
MachineInstrBuilder BuildMI(MachineFunction &MF, const DebugLoc &DL, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
const MachineOperand & getOperand(unsigned i) const
Definition: MachineInstr.h:279
Represent the analysis usage information of a pass.
INITIALIZE_PASS_END(RegBankSelect, DEBUG_TYPE,"Assign register bank of generic virtual registers", false, false) RegBankSelect
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:298
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Iterator for intrusive lists based on ilist_node.
void addOperand(MachineFunction &MF, const MachineOperand &Op)
Add the specified operand to the instruction.
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
#define DEBUG_TYPE
const DebugLoc & getDebugLoc() const
Returns the debug location id of this MachineInstr.
Definition: MachineInstr.h:250
Representation of each machine instruction.
Definition: MachineInstr.h:52
#define I(x, y, z)
Definition: MD5.cpp:54
MachineInstr * removeFromParent()
Unlink 'this' from the containing basic block, and return it without deleting it. ...
unsigned getReg() const
getReg - Returns the register number.
#define DEBUG(X)
Definition: Debug.h:100
IRTranslator LLVM IR MI
PassRegistry - This class manages the registration and intitialization of the pass subsystem as appli...
Definition: PassRegistry.h:40