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llvm-6502/lib/Target/PowerPC/PPC32AsmPrinter.cpp
Misha Brukman da2b13f694 * Output non-lazy linking stubs for external global variables 
* Get rid of dead and #if 0'd code
* Minor for loop speed-up: save end iterator instead of querying every time


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14893 91177308-0d34-0410-b5e6-96231b3b80d8
2004-07-16 20:29:04 +00:00

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//===-- Printer.cpp - Convert LLVM code to PowerPC assembly ---------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
//
// This file contains a printer that converts from our internal representation
// of machine-dependent LLVM code to PowerPC assembly language. This printer is
// the output mechanism used by `llc' and `lli -print-machineinstrs'.
//
// Documentation at http://developer.apple.com/documentation/DeveloperTools/
// Reference/Assembler/ASMIntroduction/chapter_1_section_1.html
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "asmprinter"
#include "PowerPC.h"
#include "PowerPCInstrInfo.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Mangler.h"
#include "Support/CommandLine.h"
#include "Support/Debug.h"
#include "Support/Statistic.h"
#include "Support/StringExtras.h"
#include <set>
namespace llvm {
namespace {
Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
struct Printer : public MachineFunctionPass {
/// Output stream on which we're printing assembly code.
///
std::ostream &O;
/// Target machine description which we query for reg. names, data
/// layout, etc.
///
TargetMachine &TM;
/// Name-mangler for global names.
///
Mangler *Mang;
std::set<std::string> FnStubs, GVStubs;
std::set<std::string> Strings;
Printer(std::ostream &o, TargetMachine &tm) : O(o), TM(tm), labelNumber(0)
{ }
/// Cache of mangled name for current function. This is
/// recalculated at the beginning of each call to
/// runOnMachineFunction().
///
std::string CurrentFnName;
/// Unique incrementer for label values for referencing
/// Global values.
///
unsigned int labelNumber;
virtual const char *getPassName() const {
return "PowerPC Assembly Printer";
}
void printMachineInstruction(const MachineInstr *MI);
void printOp(const MachineOperand &MO, bool elideOffsetKeyword = false);
void printConstantPool(MachineConstantPool *MCP);
bool runOnMachineFunction(MachineFunction &F);
bool doInitialization(Module &M);
bool doFinalization(Module &M);
void emitGlobalConstant(const Constant* CV);
void emitConstantValueOnly(const Constant *CV);
};
} // end of anonymous namespace
/// createPPCCodePrinterPass - Returns a pass that prints the PPC
/// assembly code for a MachineFunction to the given output stream,
/// using the given target machine description. This should work
/// regardless of whether the function is in SSA form.
///
FunctionPass *createPPCCodePrinterPass(std::ostream &o,TargetMachine &tm) {
return new Printer(o, tm);
}
/// isStringCompatible - Can we treat the specified array as a string?
/// Only if it is an array of ubytes or non-negative sbytes.
///
static bool isStringCompatible(const ConstantArray *CVA) {
const Type *ETy = cast<ArrayType>(CVA->getType())->getElementType();
if (ETy == Type::UByteTy) return true;
if (ETy != Type::SByteTy) return false;
for (unsigned i = 0; i < CVA->getNumOperands(); ++i)
if (cast<ConstantSInt>(CVA->getOperand(i))->getValue() < 0)
return false;
return true;
}
/// toOctal - Convert the low order bits of X into an octal digit.
///
static inline char toOctal(int X) {
return (X&7)+'0';
}
/// getAsCString - Return the specified array as a C compatible
/// string, only if the predicate isStringCompatible is true.
///
static void printAsCString(std::ostream &O, const ConstantArray *CVA) {
assert(isStringCompatible(CVA) && "Array is not string compatible!");
O << "\"";
for (unsigned i = 0; i < CVA->getNumOperands(); ++i) {
unsigned char C = cast<ConstantInt>(CVA->getOperand(i))->getRawValue();
if (C == '"') {
O << "\\\"";
} else if (C == '\\') {
O << "\\\\";
} else if (isprint(C)) {
O << C;
} else {
switch(C) {
case '\b': O << "\\b"; break;
case '\f': O << "\\f"; break;
case '\n': O << "\\n"; break;
case '\r': O << "\\r"; break;
case '\t': O << "\\t"; break;
default:
O << '\\';
O << toOctal(C >> 6);
O << toOctal(C >> 3);
O << toOctal(C >> 0);
break;
}
}
}
O << "\"";
}
// Print out the specified constant, without a storage class. Only the
// constants valid in constant expressions can occur here.
void Printer::emitConstantValueOnly(const Constant *CV) {
if (CV->isNullValue())
O << "0";
else if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV)) {
assert(CB == ConstantBool::True);
O << "1";
} else if (const ConstantSInt *CI = dyn_cast<ConstantSInt>(CV))
O << CI->getValue();
else if (const ConstantUInt *CI = dyn_cast<ConstantUInt>(CV))
O << CI->getValue();
else if (const ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(CV))
// This is a constant address for a global variable or function. Use the
// name of the variable or function as the address value.
O << Mang->getValueName(CPR->getValue());
else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
const TargetData &TD = TM.getTargetData();
switch(CE->getOpcode()) {
case Instruction::GetElementPtr: {
// generate a symbolic expression for the byte address
const Constant *ptrVal = CE->getOperand(0);
std::vector<Value*> idxVec(CE->op_begin()+1, CE->op_end());
if (unsigned Offset = TD.getIndexedOffset(ptrVal->getType(), idxVec)) {
O << "(";
emitConstantValueOnly(ptrVal);
O << ") + " << Offset;
} else {
emitConstantValueOnly(ptrVal);
}
break;
}
case Instruction::Cast: {
// Support only non-converting or widening casts for now, that is, ones
// that do not involve a change in value. This assertion is really gross,
// and may not even be a complete check.
Constant *Op = CE->getOperand(0);
const Type *OpTy = Op->getType(), *Ty = CE->getType();
// Remember, kids, pointers on x86 can be losslessly converted back and
// forth into 32-bit or wider integers, regardless of signedness. :-P
assert(((isa<PointerType>(OpTy)
&& (Ty == Type::LongTy || Ty == Type::ULongTy
|| Ty == Type::IntTy || Ty == Type::UIntTy))
|| (isa<PointerType>(Ty)
&& (OpTy == Type::LongTy || OpTy == Type::ULongTy
|| OpTy == Type::IntTy || OpTy == Type::UIntTy))
|| (((TD.getTypeSize(Ty) >= TD.getTypeSize(OpTy))
&& OpTy->isLosslesslyConvertibleTo(Ty))))
&& "FIXME: Don't yet support this kind of constant cast expr");
O << "(";
emitConstantValueOnly(Op);
O << ")";
break;
}
case Instruction::Add:
O << "(";
emitConstantValueOnly(CE->getOperand(0));
O << ") + (";
emitConstantValueOnly(CE->getOperand(1));
O << ")";
break;
default:
assert(0 && "Unsupported operator!");
}
} else {
assert(0 && "Unknown constant value!");
}
}
// Print a constant value or values, with the appropriate storage class as a
// prefix.
void Printer::emitGlobalConstant(const Constant *CV) {
const TargetData &TD = TM.getTargetData();
if (CV->isNullValue()) {
O << "\t.space\t " << TD.getTypeSize(CV->getType()) << "\n";
return;
} else if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
if (isStringCompatible(CVA)) {
O << "\t.ascii ";
printAsCString(O, CVA);
O << "\n";
} else { // Not a string. Print the values in successive locations
const std::vector<Use> &constValues = CVA->getValues();
for (unsigned i=0; i < constValues.size(); i++)
emitGlobalConstant(cast<Constant>(constValues[i].get()));
}
return;
} else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
// Print the fields in successive locations. Pad to align if needed!
const StructLayout *cvsLayout = TD.getStructLayout(CVS->getType());
const std::vector<Use>& constValues = CVS->getValues();
unsigned sizeSoFar = 0;
for (unsigned i=0, N = constValues.size(); i < N; i++) {
const Constant* field = cast<Constant>(constValues[i].get());
// Check if padding is needed and insert one or more 0s.
unsigned fieldSize = TD.getTypeSize(field->getType());
unsigned padSize = ((i == N-1? cvsLayout->StructSize
: cvsLayout->MemberOffsets[i+1])
- cvsLayout->MemberOffsets[i]) - fieldSize;
sizeSoFar += fieldSize + padSize;
// Now print the actual field value
emitGlobalConstant(field);
// Insert the field padding unless it's zero bytes...
if (padSize)
O << "\t.space\t " << padSize << "\n";
}
assert(sizeSoFar == cvsLayout->StructSize &&
"Layout of constant struct may be incorrect!");
return;
} else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
// FP Constants are printed as integer constants to avoid losing
// precision...
double Val = CFP->getValue();
switch (CFP->getType()->getTypeID()) {
default: assert(0 && "Unknown floating point type!");
case Type::FloatTyID: {
union FU { // Abide by C TBAA rules
float FVal;
unsigned UVal;
} U;
U.FVal = Val;
O << ".long\t" << U.UVal << "\t; float " << Val << "\n";
return;
}
case Type::DoubleTyID: {
union DU { // Abide by C TBAA rules
double FVal;
uint64_t UVal;
struct {
uint32_t MSWord;
uint32_t LSWord;
} T;
} U;
U.FVal = Val;
O << ".long\t" << U.T.MSWord << "\t; double most significant word "
<< Val << "\n";
O << ".long\t" << U.T.LSWord << "\t; double least significant word "
<< Val << "\n";
return;
}
}
} else if (CV->getType()->getPrimitiveSize() == 64) {
if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
union DU { // Abide by C TBAA rules
int64_t UVal;
struct {
uint32_t MSWord;
uint32_t LSWord;
} T;
} U;
U.UVal = CI->getRawValue();
O << ".long\t" << U.T.MSWord << "\t; Double-word most significant word "
<< U.UVal << "\n";
O << ".long\t" << U.T.LSWord << "\t; Double-word least significant word "
<< U.UVal << "\n";
return;
}
}
const Type *type = CV->getType();
O << "\t";
switch (type->getTypeID()) {
case Type::UByteTyID: case Type::SByteTyID:
O << ".byte";
break;
case Type::UShortTyID: case Type::ShortTyID:
O << ".short";
break;
case Type::BoolTyID:
case Type::PointerTyID:
case Type::UIntTyID: case Type::IntTyID:
O << ".long";
break;
case Type::ULongTyID: case Type::LongTyID:
assert (0 && "Should have already output double-word constant.");
case Type::FloatTyID: case Type::DoubleTyID:
assert (0 && "Should have already output floating point constant.");
default:
assert (0 && "Can't handle printing this type of thing");
break;
}
O << "\t";
emitConstantValueOnly(CV);
O << "\n";
}
/// printConstantPool - Print to the current output stream assembly
/// representations of the constants in the constant pool MCP. This is
/// used to print out constants which have been "spilled to memory" by
/// the code generator.
///
void Printer::printConstantPool(MachineConstantPool *MCP) {
const std::vector<Constant*> &CP = MCP->getConstants();
const TargetData &TD = TM.getTargetData();
if (CP.empty()) return;
for (unsigned i = 0, e = CP.size(); i != e; ++i) {
O << "\t.const\n";
O << "\t.align " << (unsigned)TD.getTypeAlignment(CP[i]->getType())
<< "\n";
O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t;"
<< *CP[i] << "\n";
emitGlobalConstant(CP[i]);
}
}
/// runOnMachineFunction - This uses the printMachineInstruction()
/// method to print assembly for each instruction.
///
bool Printer::runOnMachineFunction(MachineFunction &MF) {
O << "\n\n";
// What's my mangled name?
CurrentFnName = Mang->getValueName(MF.getFunction());
// Print out constants referenced by the function
printConstantPool(MF.getConstantPool());
// Print out labels for the function.
O << "\t.text\n";
O << "\t.globl\t" << CurrentFnName << "\n";
O << "\t.align 2\n";
O << CurrentFnName << ":\n";
// Print out code for the function.
for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
I != E; ++I) {
// Print a label for the basic block.
O << ".LBB" << CurrentFnName << "_" << I->getNumber() << ":\t; "
<< I->getBasicBlock()->getName() << "\n";
for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
II != E; ++II) {
// Print the assembly for the instruction.
O << "\t";
printMachineInstruction(II);
}
}
// We didn't modify anything.
return false;
}
void Printer::printOp(const MachineOperand &MO,
bool elideOffsetKeyword /* = false */) {
const MRegisterInfo &RI = *TM.getRegisterInfo();
int new_symbol;
switch (MO.getType()) {
case MachineOperand::MO_VirtualRegister:
if (Value *V = MO.getVRegValueOrNull()) {
O << "<" << V->getName() << ">";
return;
}
// FALLTHROUGH
case MachineOperand::MO_MachineRegister:
case MachineOperand::MO_CCRegister:
O << LowercaseString(RI.get(MO.getReg()).Name);
return;
case MachineOperand::MO_SignExtendedImmed:
case MachineOperand::MO_UnextendedImmed:
O << (int)MO.getImmedValue();
return;
case MachineOperand::MO_PCRelativeDisp:
std::cerr << "Shouldn't use addPCDisp() when building PPC MachineInstrs";
abort();
return;
case MachineOperand::MO_MachineBasicBlock: {
MachineBasicBlock *MBBOp = MO.getMachineBasicBlock();
O << ".LBB" << Mang->getValueName(MBBOp->getParent()->getFunction())
<< "_" << MBBOp->getNumber() << "\t; "
<< MBBOp->getBasicBlock()->getName();
return;
}
case MachineOperand::MO_ConstantPoolIndex:
O << ".CPI" << CurrentFnName << "_" << MO.getConstantPoolIndex();
return;
case MachineOperand::MO_ExternalSymbol:
O << MO.getSymbolName();
return;
case MachineOperand::MO_GlobalAddress:
if (!elideOffsetKeyword) {
GlobalValue *GV = MO.getGlobal();
std::string Name = Mang->getValueName(GV);
// Dynamically-resolved functions need a stub for the function
Function *F = dyn_cast<Function>(GV);
if (F && F->isExternal()) {
FnStubs.insert(Name);
O << "L" << Name << "$stub";
} else {
GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
// External global variables need a non-lazily-resolved stub
if (GVar && GVar->isExternal()) {
GVStubs.insert(Name);
O << "L" << Name << "$non_lazy_ptr";
} else
O << Mang->getValueName(GV);
}
}
return;
default:
O << "<unknown operand type: " << MO.getType() << ">";
return;
}
}
/// printMachineInstruction -- Print out a single PPC32 LLVM instruction
/// MI in Darwin syntax to the current output stream.
///
void Printer::printMachineInstruction(const MachineInstr *MI) {
unsigned Opcode = MI->getOpcode();
const TargetInstrInfo &TII = *TM.getInstrInfo();
const TargetInstrDescriptor &Desc = TII.get(Opcode);
unsigned int i;
unsigned int ArgCount = MI->getNumOperands();
//Desc.TSFlags & PPC32II::ArgCountMask;
unsigned int ArgType[] = {
(Desc.TSFlags >> PPC32II::Arg0TypeShift) & PPC32II::ArgTypeMask,
(Desc.TSFlags >> PPC32II::Arg1TypeShift) & PPC32II::ArgTypeMask,
(Desc.TSFlags >> PPC32II::Arg2TypeShift) & PPC32II::ArgTypeMask,
(Desc.TSFlags >> PPC32II::Arg3TypeShift) & PPC32II::ArgTypeMask,
(Desc.TSFlags >> PPC32II::Arg4TypeShift) & PPC32II::ArgTypeMask
};
assert(((Desc.TSFlags & PPC32II::VMX) == 0) &&
"Instruction requires VMX support");
assert(((Desc.TSFlags & PPC32II::PPC64) == 0) &&
"Instruction requires 64 bit support");
++EmittedInsts;
if (Opcode == PPC32::IMPLICIT_DEF) {
O << "; IMPLICIT DEF ";
printOp(MI->getOperand(0));
O << "\n";
return;
}
// FIXME: should probably be converted to cout.width and cout.fill
if (Opcode == PPC32::MovePCtoLR) {
O << "bl \"L0000" << labelNumber << "$pb\"\n";
O << "\"L0000" << labelNumber << "$pb\":\n";
O << "\tmflr ";
printOp(MI->getOperand(0));
O << "\n";
return;
}
O << TII.getName(MI->getOpcode()) << " ";
DEBUG(std::cerr << TII.getName(MI->getOpcode()) << " expects "
<< ArgCount << " args\n");
if (Opcode == PPC32::LOADLoAddr) {
printOp(MI->getOperand(0));
O << ", lo16(";
printOp(MI->getOperand(2));
O << "-\"L0000" << labelNumber << "$pb\")";
labelNumber++;
O << "(";
if (MI->getOperand(1).getReg() == PPC32::R0)
O << "0";
else
printOp(MI->getOperand(1));
O << ")\n";
} else if (Opcode == PPC32::LOADHiAddr) {
printOp(MI->getOperand(0));
O << ", ";
if (MI->getOperand(1).getReg() == PPC32::R0)
O << "0";
else
printOp(MI->getOperand(1));
O << ", ha16(" ;
printOp(MI->getOperand(2));
O << "-\"L0000" << labelNumber << "$pb\")\n";
} else if (ArgCount == 3 && ArgType[1] == PPC32II::Disimm16) {
printOp(MI->getOperand(0));
O << ", ";
printOp(MI->getOperand(1));
O << "(";
if (MI->getOperand(2).hasAllocatedReg() &&
MI->getOperand(2).getReg() == PPC32::R0)
O << "0";
else
printOp(MI->getOperand(2));
O << ")\n";
} else {
for (i = 0; i < ArgCount; ++i) {
if (i == 1 && ArgCount == 3 && ArgType[2] == PPC32II::Simm16 &&
MI->getOperand(1).hasAllocatedReg() &&
MI->getOperand(1).getReg() == PPC32::R0) {
O << "0";
} else {
printOp(MI->getOperand(i));
}
if (ArgCount - 1 == i)
O << "\n";
else
O << ", ";
}
}
}
bool Printer::doInitialization(Module &M) {
Mang = new Mangler(M, true);
return false; // success
}
// SwitchSection - Switch to the specified section of the executable if we are
// not already in it!
//
static void SwitchSection(std::ostream &OS, std::string &CurSection,
const char *NewSection) {
if (CurSection != NewSection) {
CurSection = NewSection;
if (!CurSection.empty())
OS << "\t" << NewSection << "\n";
}
}
bool Printer::doFinalization(Module &M) {
const TargetData &TD = TM.getTargetData();
std::string CurSection;
// Print out module-level global variables here.
for (Module::const_giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
if (I->hasInitializer()) { // External global require no code
O << "\n\n";
std::string name = Mang->getValueName(I);
Constant *C = I->getInitializer();
unsigned Size = TD.getTypeSize(C->getType());
unsigned Align = TD.getTypeAlignment(C->getType());
if (C->isNullValue() &&
(I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
I->hasWeakLinkage() /* FIXME: Verify correct */)) {
SwitchSection(O, CurSection, ".data");
if (I->hasInternalLinkage())
O << "\t.lcomm " << name << "," << TD.getTypeSize(C->getType())
<< "," << (unsigned)TD.getTypeAlignment(C->getType());
else
O << "\t.comm " << name << "," << TD.getTypeSize(C->getType());
O << "\t\t; ";
WriteAsOperand(O, I, true, true, &M);
O << "\n";
} else {
switch (I->getLinkage()) {
case GlobalValue::LinkOnceLinkage:
case GlobalValue::WeakLinkage: // FIXME: Verify correct for weak.
// Nonnull linkonce -> weak
O << "\t.weak " << name << "\n";
SwitchSection(O, CurSection, "");
O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
break;
case GlobalValue::AppendingLinkage:
// FIXME: appending linkage variables should go into a section of
// their name or something. For now, just emit them as external.
case GlobalValue::ExternalLinkage:
// If external or appending, declare as a global symbol
O << "\t.globl " << name << "\n";
// FALL THROUGH
case GlobalValue::InternalLinkage:
SwitchSection(O, CurSection, ".data");
break;
}
O << "\t.align " << Align << "\n";
O << name << ":\t\t\t\t; ";
WriteAsOperand(O, I, true, true, &M);
O << " = ";
WriteAsOperand(O, C, false, false, &M);
O << "\n";
emitGlobalConstant(C);
}
}
// Output stubs for dynamically-linked functions
for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
i != e; ++i)
{
O << "\t.picsymbol_stub\n";
O << "L" << *i << "$stub:\n";
O << "\t.indirect_symbol " << *i << "\n";
O << "\tmflr r0\n";
O << "\tbl L0$" << *i << "\n";
O << "L0$" << *i << ":\n";
O << "\tmflr r11\n";
O << "\taddis r11,r11,ha16(L" << *i << "$lazy_ptr-L0$" << *i << ")\n";
O << "\tmtlr r0\n";
O << "\tlwz r12,lo16(L" << *i << "$lazy_ptr-L0$" << *i << ")(r11)\n";
O << "\tmtctr r12\n";
O << "\taddi r11,r11,lo16(L" << *i << "$lazy_ptr - L0$" << *i << ")\n";
O << "\tbctr\n";
O << ".data\n";
O << ".lazy_symbol_pointer\n";
O << "L" << *i << "$lazy_ptr:\n";
O << ".indirect_symbol " << *i << "\n";
O << ".long dyld_stub_binding_helper\n";
}
O << "\n";
// Output stubs for external global variables
if (GVStubs.begin() != GVStubs.end())
O << "\t.non_lazy_symbol_pointer\n";
for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
i != e; ++i) {
O << "L" << *i << "$non_lazy_ptr:\n";
O << "\t.indirect_symbol " << *i << "\n";
O << "\t.long\t0\n";
}
delete Mang;
return false; // success
}
} // End llvm namespace
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