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llvm-6502/lib/Target/SparcV9/SparcV9CodeEmitter.cpp
Reid Spencer 4b828e6384 Clean up some uninitialized variables and missing return statements that 
GCC 4.0.0 compiler (sometimes incorrectly) warns about under release build.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22249 91177308-0d34-0410-b5e6-96231b3b80d8
2005-06-18 17:37:34 +00:00

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//===-- SparcV9CodeEmitter.cpp --------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// SPARC-specific backend for emitting machine code to memory.
//
// This module also contains the code for lazily resolving the targets of call
// instructions, including the callback used to redirect calls to functions for
// which the code has not yet been generated into the JIT compiler.
//
// This file #includes SparcV9GenCodeEmitter.inc, which contains the code for
// getBinaryCodeForInstr(), a method that converts a MachineInstr into the
// corresponding binary machine code word.
//
//===----------------------------------------------------------------------===//
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/Debug.h"
#include "SparcV9Internals.h"
#include "SparcV9TargetMachine.h"
#include "SparcV9RegInfo.h"
#include "SparcV9CodeEmitter.h"
#include "SparcV9Relocations.h"
#include "MachineFunctionInfo.h"
using namespace llvm;
bool SparcV9TargetMachine::addPassesToEmitMachineCode(FunctionPassManager &PM,
MachineCodeEmitter &MCE) {
PM.add(new SparcV9CodeEmitter(*this, MCE));
PM.add(createSparcV9MachineCodeDestructionPass());
return false;
}
SparcV9CodeEmitter::SparcV9CodeEmitter(TargetMachine &tm,
MachineCodeEmitter &M): TM(tm), MCE(M) {}
void SparcV9CodeEmitter::emitWord(unsigned Val) {
MCE.emitWord(Val);
}
unsigned
SparcV9CodeEmitter::getRealRegNum(unsigned fakeReg,
MachineInstr &MI) {
const SparcV9RegInfo &RI = *TM.getRegInfo();
unsigned regClass = 0, regType = RI.getRegType(fakeReg);
// At least map fakeReg into its class
fakeReg = RI.getClassRegNum(fakeReg, regClass);
switch (regClass) {
case SparcV9RegInfo::IntRegClassID: {
// SparcV9 manual, p31
static const unsigned IntRegMap[] = {
// "o0", "o1", "o2", "o3", "o4", "o5", "o7",
8, 9, 10, 11, 12, 13, 15,
// "l0", "l1", "l2", "l3", "l4", "l5", "l6", "l7",
16, 17, 18, 19, 20, 21, 22, 23,
// "i0", "i1", "i2", "i3", "i4", "i5", "i6", "i7",
24, 25, 26, 27, 28, 29, 30, 31,
// "g0", "g1", "g2", "g3", "g4", "g5", "g6", "g7",
0, 1, 2, 3, 4, 5, 6, 7,
// "o6"
14
};
return IntRegMap[fakeReg];
break;
}
case SparcV9RegInfo::FloatRegClassID: {
DEBUG(std::cerr << "FP reg: " << fakeReg << "\n");
if (regType == SparcV9RegInfo::FPSingleRegType) {
// only numbered 0-31, hence can already fit into 5 bits (and 6)
DEBUG(std::cerr << "FP single reg, returning: " << fakeReg << "\n");
} else if (regType == SparcV9RegInfo::FPDoubleRegType) {
// FIXME: This assumes that we only have 5-bit register fields!
// From SparcV9 Manual, page 40.
// The bit layout becomes: b[4], b[3], b[2], b[1], b[5]
fakeReg |= (fakeReg >> 5) & 1;
fakeReg &= 0x1f;
DEBUG(std::cerr << "FP double reg, returning: " << fakeReg << "\n");
}
return fakeReg;
}
case SparcV9RegInfo::IntCCRegClassID: {
/* xcc, icc, ccr */
static const unsigned IntCCReg[] = { 6, 4, 2 };
assert(fakeReg < sizeof(IntCCReg)/sizeof(IntCCReg[0])
&& "CC register out of bounds for IntCCReg map");
DEBUG(std::cerr << "IntCC reg: " << IntCCReg[fakeReg] << "\n");
return IntCCReg[fakeReg];
}
case SparcV9RegInfo::FloatCCRegClassID: {
/* These are laid out %fcc0 - %fcc3 => 0 - 3, so are correct */
DEBUG(std::cerr << "FP CC reg: " << fakeReg << "\n");
return fakeReg;
}
case SparcV9RegInfo::SpecialRegClassID: {
// Currently only "special" reg is %fsr, which is encoded as 1 in
// instructions and 0 in SparcV9SpecialRegClass.
static const unsigned SpecialReg[] = { 1 };
assert(fakeReg < sizeof(SpecialReg)/sizeof(SpecialReg[0])
&& "Special register out of bounds for SpecialReg map");
DEBUG(std::cerr << "Special reg: " << SpecialReg[fakeReg] << "\n");
return SpecialReg[fakeReg];
}
default:
assert(0 && "Invalid unified register number in getRealRegNum");
return fakeReg;
}
}
int64_t SparcV9CodeEmitter::getMachineOpValue(MachineInstr &MI,
MachineOperand &MO) {
int64_t rv = 0; // Return value; defaults to 0 for unhandled cases
// or things that get fixed up later by the JIT.
if (MO.isPCRelativeDisp() || MO.isGlobalAddress()) {
DEBUG(std::cerr << "PCRelativeDisp: ");
Value *V = MO.getVRegValue();
if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
DEBUG(std::cerr << "Saving reference to BB (VReg)\n");
unsigned* CurrPC = (unsigned*)(intptr_t)MCE.getCurrentPCValue();
BBRefs.push_back(std::make_pair(BB, std::make_pair(CurrPC, &MI)));
} else if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
// The real target of the branch is CI = PC + (rv * 4)
// So undo that: give the instruction (CI - PC) / 4
rv = (CI->getRawValue() - MCE.getCurrentPCValue()) / 4;
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
unsigned Reloc = 0;
if (MI.getOpcode() == V9::CALL) {
Reloc = V9::reloc_pcrel_call;
} else if (MI.getOpcode() == V9::SETHI) {
if (MO.isHiBits64())
Reloc = V9::reloc_sethi_hh;
else if (MO.isHiBits32())
Reloc = V9::reloc_sethi_lm;
else
assert(0 && "Unknown relocation!");
} else if (MI.getOpcode() == V9::ORi) {
if (MO.isLoBits32())
Reloc = V9::reloc_or_lo;
else if (MO.isLoBits64())
Reloc = V9::reloc_or_hm;
else
assert(0 && "Unknown relocation!");
} else {
assert(0 && "Unknown relocation!");
}
MCE.addRelocation(MachineRelocation(MCE.getCurrentPCOffset(), Reloc, GV));
rv = 0;
} else {
std::cerr << "ERROR: PC relative disp unhandled:" << MO << "\n";
abort();
}
} else if (MO.isRegister() || MO.getType() == MachineOperand::MO_CCRegister)
{
// This is necessary because the SparcV9 backend doesn't actually lay out
// registers in the real fashion -- it skips those that it chooses not to
// allocate, i.e. those that are the FP, SP, etc.
unsigned fakeReg = MO.getReg();
unsigned realRegByClass = getRealRegNum(fakeReg, MI);
DEBUG(std::cerr << MO << ": Reg[" << std::dec << fakeReg << "] => "
<< realRegByClass << " (LLC: "
<< TM.getRegInfo()->getUnifiedRegName(fakeReg) << ")\n");
rv = realRegByClass;
} else if (MO.isImmediate()) {
rv = MO.getImmedValue();
DEBUG(std::cerr << "immed: " << rv << "\n");
} else if (MO.isMachineBasicBlock()) {
// Duplicate code of the above case for VirtualRegister, BasicBlock...
// It should really hit this case, but SparcV9 backend uses VRegs instead
DEBUG(std::cerr << "Saving reference to MBB\n");
const BasicBlock *BB = MO.getMachineBasicBlock()->getBasicBlock();
unsigned* CurrPC = (unsigned*)(intptr_t)MCE.getCurrentPCValue();
BBRefs.push_back(std::make_pair(BB, std::make_pair(CurrPC, &MI)));
} else if (MO.isExternalSymbol()) {
// SparcV9 backend doesn't generate this (yet...)
std::cerr << "ERROR: External symbol unhandled: " << MO << "\n";
abort();
} else if (MO.isFrameIndex()) {
// SparcV9 backend doesn't generate this (yet...)
int FrameIndex = MO.getFrameIndex();
std::cerr << "ERROR: Frame index unhandled.\n";
abort();
} else if (MO.isConstantPoolIndex()) {
unsigned Index = MO.getConstantPoolIndex();
rv = MCE.getConstantPoolEntryAddress(Index);
} else {
std::cerr << "ERROR: Unknown type of MachineOperand: " << MO << "\n";
abort();
}
// Finally, deal with the various bitfield-extracting functions that
// are used in SPARC assembly. (Some of these make no sense in combination
// with some of the above; we'll trust that the instruction selector
// will not produce nonsense, and not check for valid combinations here.)
if (MO.isLoBits32()) { // %lo(val) == %lo() in SparcV9 ABI doc
return rv & 0x03ff;
} else if (MO.isHiBits32()) { // %lm(val) == %hi() in SparcV9 ABI doc
return (rv >> 10) & 0x03fffff;
} else if (MO.isLoBits64()) { // %hm(val) == %ulo() in SparcV9 ABI doc
return (rv >> 32) & 0x03ff;
} else if (MO.isHiBits64()) { // %hh(val) == %uhi() in SparcV9 ABI doc
return rv >> 42;
} else { // (unadorned) val
return rv;
}
}
unsigned SparcV9CodeEmitter::getValueBit(int64_t Val, unsigned bit) {
Val >>= bit;
return (Val & 1);
}
bool SparcV9CodeEmitter::runOnMachineFunction(MachineFunction &MF) {
MCE.startFunction(MF);
DEBUG(std::cerr << "Starting function " << MF.getFunction()->getName()
<< ", address: " << "0x" << std::hex
<< (long)MCE.getCurrentPCValue() << "\n");
MCE.emitConstantPool(MF.getConstantPool());
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
emitBasicBlock(*I);
MCE.finishFunction(MF);
DEBUG(std::cerr << "Finishing fn " << MF.getFunction()->getName() << "\n");
// Resolve branches to BasicBlocks for the entire function
for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) {
long Location = BBLocations[BBRefs[i].first];
unsigned *Ref = BBRefs[i].second.first;
MachineInstr *MI = BBRefs[i].second.second;
DEBUG(std::cerr << "Fixup @ " << std::hex << Ref << " to 0x" << Location
<< " in instr: " << std::dec << *MI);
for (unsigned ii = 0, ee = MI->getNumOperands(); ii != ee; ++ii) {
MachineOperand &op = MI->getOperand(ii);
if (op.isPCRelativeDisp()) {
// the instruction's branch target is made such that it branches to
// PC + (branchTarget * 4), so undo that arithmetic here:
// Location is the target of the branch
// Ref is the location of the instruction, and hence the PC
int64_t branchTarget = (Location - (long)Ref) >> 2;
// Save the flags.
bool loBits32=false, hiBits32=false, loBits64=false, hiBits64=false;
if (op.isLoBits32()) { loBits32=true; }
if (op.isHiBits32()) { hiBits32=true; }
if (op.isLoBits64()) { loBits64=true; }
if (op.isHiBits64()) { hiBits64=true; }
MI->SetMachineOperandConst(ii, MachineOperand::MO_SignExtendedImmed,
branchTarget);
if (loBits32) { MI->getOperand(ii).markLo32(); }
else if (hiBits32) { MI->getOperand(ii).markHi32(); }
else if (loBits64) { MI->getOperand(ii).markLo64(); }
else if (hiBits64) { MI->getOperand(ii).markHi64(); }
DEBUG(std::cerr << "Rewrote BB ref: ");
unsigned fixedInstr = SparcV9CodeEmitter::getBinaryCodeForInstr(*MI);
MCE.emitWordAt (fixedInstr, Ref);
break;
}
}
}
BBRefs.clear();
BBLocations.clear();
return false;
}
void SparcV9CodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
currBB = MBB.getBasicBlock();
BBLocations[currBB] = MCE.getCurrentPCValue();
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I)
if (I->getOpcode() != V9::RDCCR) {
emitWord(getBinaryCodeForInstr(*I));
} else {
// FIXME: The tblgen produced code emitter cannot deal with the fact that
// machine operand #0 of the RDCCR instruction should be ignored. This is
// really a bug in the representation of the RDCCR instruction (which has
// no need to explicitly represent the CCR dest), but we hack around it
// here.
unsigned RegNo = getMachineOpValue(*I, I->getOperand(1));
RegNo &= (1<<5)-1;
emitWord((RegNo << 25) | 2168487936U);
}
}
#include "SparcV9GenCodeEmitter.inc"
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