mirror of
				https://github.com/c64scene-ar/llvm-6502.git
				synced 2025-10-31 08:16:47 +00:00 
			
		
		
		
	static global variables whose addresses are taken.  This allows us to
convert the following code for taking the address of a static function foo
        addis r2, r30, ha16(Ll1__2E_foo_2$non_lazy_ptr-"L00001$pb")
        lwz r3, lo16(Ll1__2E_foo_2$non_lazy_ptr-"L00001$pb")(r2)
which also includes linker stub code emitted at the end of the .s file not
shown here, and replace it with this:
        addis r2, r30, ha16(l1__2E_foo_2-"L00001$pb")
        la r3, lo16(l1__2E_foo_2-"L00001$pb")(r2)
which in addition to not needing linker help, also has no load instruction.
For those not up on PowerPC mnemonics, la is shorthand for add immediate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18239 91177308-0d34-0410-b5e6-96231b3b80d8
		
	
		
			
				
	
	
		
			255 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			255 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===-- PPC32CodeEmitter.cpp - JIT Code Emitter for PowerPC32 -----*- C++ -*-=//
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| // 
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file was developed by the LLVM research group and is distributed under
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| // the University of Illinois Open Source License. See LICENSE.TXT for details.
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| // 
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| //===----------------------------------------------------------------------===//
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| // 
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| // This file defines the PowerPC 32-bit CodeEmitter and associated machinery to
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| // JIT-compile bytecode to native PowerPC.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "PPC32TargetMachine.h"
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| #include "PPC32Relocations.h"
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| #include "PowerPC.h"
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| #include "llvm/Module.h"
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| #include "llvm/CodeGen/MachineCodeEmitter.h"
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| #include "llvm/CodeGen/MachineFunctionPass.h"
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| #include "llvm/CodeGen/MachineInstrBuilder.h"
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| #include "llvm/CodeGen/Passes.h"
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| #include "llvm/Support/Debug.h"
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| using namespace llvm;
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| 
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| namespace {
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|   class PPC32CodeEmitter : public MachineFunctionPass {
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|     TargetMachine &TM;
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|     MachineCodeEmitter &MCE;
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| 
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|     /// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
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|     /// its address in the function into this pointer.
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|     void *MovePCtoLROffset;
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| 
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|     // Tracks which instruction references which BasicBlock
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|     std::vector<std::pair<MachineBasicBlock*, unsigned*> > BBRefs;
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|     // Tracks where each BasicBlock starts
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|     std::map<MachineBasicBlock*, long> BBLocations;
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| 
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|     /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
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|     ///
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|     int getMachineOpValue(MachineInstr &MI, MachineOperand &MO);
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| 
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|   public:
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|     PPC32CodeEmitter(TargetMachine &T, MachineCodeEmitter &M) 
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|       : TM(T), MCE(M) {}
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| 
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|     const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
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| 
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|     /// runOnMachineFunction - emits the given MachineFunction to memory
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|     ///
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|     bool runOnMachineFunction(MachineFunction &MF);
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| 
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|     /// emitBasicBlock - emits the given MachineBasicBlock to memory
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|     ///
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|     void emitBasicBlock(MachineBasicBlock &MBB);
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| 
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|     /// emitWord - write a 32-bit word to memory at the current PC
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|     ///
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|     void emitWord(unsigned w) { MCE.emitWord(w); }
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|     
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|     /// getValueBit - return the particular bit of Val
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|     ///
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|     unsigned getValueBit(int64_t Val, unsigned bit) { return (Val >> bit) & 1; }
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| 
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|     /// getBinaryCodeForInstr - This function, generated by the
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|     /// CodeEmitterGenerator using TableGen, produces the binary encoding for
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|     /// machine instructions.
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|     ///
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|     unsigned getBinaryCodeForInstr(MachineInstr &MI);
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|   };
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| }
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| 
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| /// addPassesToEmitMachineCode - Add passes to the specified pass manager to get
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| /// machine code emitted.  This uses a MachineCodeEmitter object to handle
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| /// actually outputting the machine code and resolving things like the address
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| /// of functions.  This method should returns true if machine code emission is
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| /// not supported.
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| ///
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| bool PPC32TargetMachine::addPassesToEmitMachineCode(FunctionPassManager &PM,
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|                                                     MachineCodeEmitter &MCE) {
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|   // Machine code emitter pass for PowerPC
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|   PM.add(new PPC32CodeEmitter(*this, MCE)); 
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|   // Delete machine code for this function after emitting it
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|   PM.add(createMachineCodeDeleter());
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|   return false;
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| }
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| 
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| bool PPC32CodeEmitter::runOnMachineFunction(MachineFunction &MF) {
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|   MovePCtoLROffset = 0;
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|   MCE.startFunction(MF);
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|   MCE.emitConstantPool(MF.getConstantPool());
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|   for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
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|     emitBasicBlock(*BB);
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|   MCE.finishFunction(MF);
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| 
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|   // Resolve branches to BasicBlocks for the entire function
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|   for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) {
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|     intptr_t Location = BBLocations[BBRefs[i].first];
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|     unsigned *Ref = BBRefs[i].second;
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|     DEBUG(std::cerr << "Fixup @ " << (void*)Ref << " to " << (void*)Location
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|                     << "\n");
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|     unsigned Instr = *Ref;
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|     intptr_t BranchTargetDisp = (Location - (intptr_t)Ref) >> 2;
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|     
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|     switch (Instr >> 26) {
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|     default: assert(0 && "Unknown branch user!");
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|     case 18:  // This is B or BL
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|       *Ref |= (BranchTargetDisp & ((1 << 24)-1)) << 2;
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|       break;
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|     case 16:  // This is BLT,BLE,BEQ,BGE,BGT,BNE, or other bcx instruction
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|       *Ref |= (BranchTargetDisp & ((1 << 14)-1)) << 2;
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|       break;
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|     }
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|   }
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|   BBRefs.clear();
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|   BBLocations.clear();
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| 
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|   return false;
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| }
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| 
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| void PPC32CodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
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|   BBLocations[&MBB] = MCE.getCurrentPCValue();
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|   for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
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|     MachineInstr &MI = *I;
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|     unsigned Opcode = MI.getOpcode();
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|     switch (MI.getOpcode()) {
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|     default:
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|       emitWord(getBinaryCodeForInstr(*I));
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|       break;
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|     case PPC::IMPLICIT_DEF:
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|       break; // pseudo opcode, no side effects
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|     case PPC::MovePCtoLR:
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|       assert(MovePCtoLROffset == 0 &&
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|              "Multiple MovePCtoLR instructions in the function?");
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|       MovePCtoLROffset = (void*)(intptr_t)MCE.getCurrentPCValue();
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|       emitWord(0x48000005);    // bl 1
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|       break;
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|     }
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|   }
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| }
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| 
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| static unsigned enumRegToMachineReg(unsigned enumReg) {
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|   switch (enumReg) {
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|   case PPC::R0 :  case PPC::F0 :  case PPC::CR0:  return  0;  
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|   case PPC::R1 :  case PPC::F1 :  case PPC::CR1:  return  1; 
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|   case PPC::R2 :  case PPC::F2 :  case PPC::CR2:  return  2;
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|   case PPC::R3 :  case PPC::F3 :  case PPC::CR3:  return  3; 
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|   case PPC::R4 :  case PPC::F4 :  case PPC::CR4:  return  4; 
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|   case PPC::R5 :  case PPC::F5 :  case PPC::CR5:  return  5;
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|   case PPC::R6 :  case PPC::F6 :  case PPC::CR6:  return  6; 
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|   case PPC::R7 :  case PPC::F7 :  case PPC::CR7:  return  7; 
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|   case PPC::R8 :  case PPC::F8 :  return  8;
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|   case PPC::R9 :  case PPC::F9 :  return  9; 
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|   case PPC::R10:  case PPC::F10:  return 10; 
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|   case PPC::R11:  case PPC::F11:  return 11;
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|   case PPC::R12:  case PPC::F12:  return 12; 
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|   case PPC::R13:  case PPC::F13:  return 13; 
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|   case PPC::R14:  case PPC::F14:  return 14;
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|   case PPC::R15:  case PPC::F15:  return 15; 
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|   case PPC::R16:  case PPC::F16:  return 16; 
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|   case PPC::R17:  case PPC::F17:  return 17;
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|   case PPC::R18:  case PPC::F18:  return 18; 
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|   case PPC::R19:  case PPC::F19:  return 19; 
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|   case PPC::R20:  case PPC::F20:  return 20;
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|   case PPC::R21:  case PPC::F21:  return 21;
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|   case PPC::R22:  case PPC::F22:  return 22; 
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|   case PPC::R23:  case PPC::F23:  return 23; 
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|   case PPC::R24:  case PPC::F24:  return 24;
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|   case PPC::R25:  case PPC::F25:  return 25; 
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|   case PPC::R26:  case PPC::F26:  return 26; 
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|   case PPC::R27:  case PPC::F27:  return 27;
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|   case PPC::R28:  case PPC::F28:  return 28; 
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|   case PPC::R29:  case PPC::F29:  return 29; 
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|   case PPC::R30:  case PPC::F30:  return 30;
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|   case PPC::R31:  case PPC::F31:  return 31;
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|   default:
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|     std::cerr << "Unhandled reg in enumRegToRealReg!\n";
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|     abort();
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|   }
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| }
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| 
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| int PPC32CodeEmitter::getMachineOpValue(MachineInstr &MI, MachineOperand &MO) {
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|                                         
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|   int rv = 0; // Return value; defaults to 0 for unhandled cases
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|                   // or things that get fixed up later by the JIT.
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|   if (MO.isRegister()) {
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|     rv = enumRegToMachineReg(MO.getReg());
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|   } else if (MO.isImmediate()) {
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|     rv = MO.getImmedValue();
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|   } else if (MO.isGlobalAddress()) {
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|     GlobalValue *GV = MO.getGlobal();
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|     unsigned Reloc = 0;
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|     int Offset = 0;
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|     if (MI.getOpcode() == PPC::CALLpcrel)
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|       Reloc = PPC::reloc_pcrel_bx;
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|     else {
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|       assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
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|       Offset = -((intptr_t)MovePCtoLROffset+4);
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| 
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|       if (MI.getOpcode() == PPC::LOADHiAddr) {
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|         if (GV->hasWeakLinkage() || GV->isExternal())
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|           Reloc = PPC::reloc_absolute_ptr_high;   // Pointer to stub
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|         else
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|           Reloc = PPC::reloc_absolute_high;       // Pointer to symbol
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| 
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|       } else if (MI.getOpcode() == PPC::LA) {
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|         assert(!(GV->hasWeakLinkage() || GV->isExternal())
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|                && "Something in the ISEL changed\n");
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| 
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|         Reloc = PPC::reloc_absolute_low;
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|       } else if (MI.getOpcode() == PPC::LWZ) {
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|         Reloc = PPC::reloc_absolute_ptr_low;
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| 
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|         assert((GV->hasWeakLinkage() || GV->isExternal()) &&
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|                "Something in the ISEL changed\n");
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|       } else {
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|         // These don't show up for global value references AFAIK, only for
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|         // constant pool refs: PPC::LFS, PPC::LFD
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|         assert(0 && "Unknown instruction for relocation!");
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|       }
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|     }
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|     MCE.addRelocation(MachineRelocation(MCE.getCurrentPCOffset(),
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|                                         Reloc, MO.getGlobal(), Offset));
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|   } else if (MO.isMachineBasicBlock()) {
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|     unsigned* CurrPC = (unsigned*)(intptr_t)MCE.getCurrentPCValue();
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|     BBRefs.push_back(std::make_pair(MO.getMachineBasicBlock(), CurrPC));
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|   } else if (MO.isConstantPoolIndex()) {
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|     unsigned index = MO.getConstantPoolIndex();
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|     assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
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|     rv = MCE.getConstantPoolEntryAddress(index) - (intptr_t)MovePCtoLROffset-4;
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| 
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|     unsigned Opcode = MI.getOpcode();
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|     if (Opcode == PPC::LOADHiAddr) {
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|       // LoadHiAddr wants hi16(addr - &MovePCtoLR)
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|       if ((short)rv < 0) rv += 1 << 16;
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|       rv >>= 16;
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|     } else if (Opcode == PPC::LWZ || Opcode == PPC::LA ||
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|                Opcode == PPC::LFS || Opcode == PPC::LFD) {
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|       // These load opcodes want lo16(addr - &MovePCtoLR)
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|       rv &= 0xffff;
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|     } else {
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|       assert(0 && "Unknown constant pool using instruction!");
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|     }
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|   } else {
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|     std::cerr << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
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|     abort();
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|   }
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| 
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|   return rv;
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| }
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| 
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| #include "PPC32GenCodeEmitter.inc"
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| 
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