//===-- X86/X86CodeEmitter.cpp - Convert X86 code to machine code ---------===//
-//
+//
// 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 the pass that transforms the X86 machine instructions into
-// actual executable machine code.
+// relocatable machine code.
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "jit"
#include "X86TargetMachine.h"
+#include "X86Relocations.h"
#include "X86.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Function.h"
-#include "llvm/Support/Debug.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/Config/alloca.h"
+#include "llvm/Target/TargetOptions.h"
+#include <iostream>
using namespace llvm;
namespace {
Statistic<>
NumEmitted("x86-emitter", "Number of machine instructions emitted");
-
- class JITResolver {
- MachineCodeEmitter &MCE;
-
- // LazyCodeGenMap - Keep track of call sites for functions that are to be
- // lazily resolved.
- std::map<unsigned, Function*> LazyCodeGenMap;
-
- // LazyResolverMap - Keep track of the lazy resolver created for a
- // particular function so that we can reuse them if necessary.
- std::map<Function*, unsigned> LazyResolverMap;
- public:
- JITResolver(MachineCodeEmitter &mce) : MCE(mce) {}
- unsigned getLazyResolver(Function *F);
- unsigned addFunctionReference(unsigned Address, Function *F);
-
- private:
- unsigned emitStubForFunction(Function *F);
- static void CompilationCallback();
- unsigned resolveFunctionReference(unsigned RetAddr);
- };
-
- static JITResolver &getResolver(MachineCodeEmitter &MCE) {
- static JITResolver *TheJITResolver = 0;
- if (TheJITResolver == 0)
- TheJITResolver = new JITResolver(MCE);
- return *TheJITResolver;
- }
-}
-
-
-void *X86JITInfo::getJITStubForFunction(Function *F, MachineCodeEmitter &MCE) {
- return (void*)(intptr_t)getResolver(MCE).getLazyResolver(F);
-}
-
-void X86JITInfo::replaceMachineCodeForFunction (void *Old, void *New) {
- unsigned char *OldByte = (unsigned char *) Old;
- *OldByte++ = 0xE9; // Emit JMP opcode.
- int32_t *OldWord = (int32_t *) OldByte;
- int32_t NewAddr = (intptr_t) New;
- int32_t OldAddr = (intptr_t) OldWord;
- *OldWord = NewAddr - OldAddr - 4; // Emit PC-relative addr of New code.
-}
-
-/// addFunctionReference - This method is called when we need to emit the
-/// address of a function that has not yet been emitted, so we don't know the
-/// address. Instead, we emit a call to the CompilationCallback method, and
-/// keep track of where we are.
-///
-unsigned JITResolver::addFunctionReference(unsigned Address, Function *F) {
- DEBUG(std::cerr << "Emitting lazily resolved reference to function '"
- << F->getName() << "' at address " << std::hex << Address << "\n");
- LazyCodeGenMap[Address] = F;
- return (intptr_t)&JITResolver::CompilationCallback;
-}
-
-unsigned JITResolver::resolveFunctionReference(unsigned RetAddr) {
- std::map<unsigned, Function*>::iterator I = LazyCodeGenMap.find(RetAddr);
- assert(I != LazyCodeGenMap.end() && "Not in map!");
- Function *F = I->second;
- LazyCodeGenMap.erase(I);
- return MCE.forceCompilationOf(F);
-}
-
-unsigned JITResolver::getLazyResolver(Function *F) {
- std::map<Function*, unsigned>::iterator I = LazyResolverMap.lower_bound(F);
- if (I != LazyResolverMap.end() && I->first == F) return I->second;
-
-//std::cerr << "Getting lazy resolver for : " << ((Value*)F)->getName() << "\n";
-
- unsigned Stub = emitStubForFunction(F);
- LazyResolverMap.insert(I, std::make_pair(F, Stub));
- return Stub;
-}
-
-#ifdef _MSC_VER
-#pragma optimize("y", off)
-#endif
-
-void JITResolver::CompilationCallback() {
-#ifdef _MSC_VER
- unsigned *StackPtr, RetAddr;
- __asm mov StackPtr, ebp;
- __asm mov eax, DWORD PTR [ebp + 4];
- __asm mov RetAddr, eax;
-#else
- unsigned *StackPtr = (unsigned*)__builtin_frame_address(0);
- unsigned RetAddr = (unsigned)(intptr_t)__builtin_return_address(0);
-
- // FIXME: __builtin_frame_address doesn't work if frame pointer elimination
- // has been performed. Having a variable sized alloca disables frame pointer
- // elimination currently, even if it's dead. This is a gross hack.
- alloca(10+(RetAddr >> 31));
-
-#endif
- assert(StackPtr[1] == RetAddr &&
- "Could not find return address on the stack!");
-
- // It's a stub if there is an interrupt marker after the call...
- bool isStub = ((unsigned char*)(intptr_t)RetAddr)[0] == 0xCD;
-
- // The call instruction should have pushed the return value onto the stack...
- RetAddr -= 4; // Backtrack to the reference itself...
-
-#if 0
- DEBUG(std::cerr << "In callback! Addr=0x" << std::hex << RetAddr
- << " ESP=0x" << (unsigned)StackPtr << std::dec
- << ": Resolving call to function: "
- << TheVM->getFunctionReferencedName((void*)RetAddr) << "\n");
-#endif
-
- // Sanity check to make sure this really is a call instruction...
- assert(((unsigned char*)(intptr_t)RetAddr)[-1] == 0xE8 &&"Not a call instr!");
-
- JITResolver &JR = getResolver(*(MachineCodeEmitter*)0);
- unsigned NewVal = JR.resolveFunctionReference(RetAddr);
-
- // Rewrite the call target... so that we don't fault every time we execute
- // the call.
- *(unsigned*)(intptr_t)RetAddr = NewVal-RetAddr-4;
-
- if (isStub) {
- // If this is a stub, rewrite the call into an unconditional branch
- // instruction so that two return addresses are not pushed onto the stack
- // when the requested function finally gets called. This also makes the
- // 0xCD byte (interrupt) dead, so the marker doesn't effect anything.
- ((unsigned char*)(intptr_t)RetAddr)[-1] = 0xE9;
- }
-
- // Change the return address to reexecute the call instruction...
- StackPtr[1] -= 5;
-}
-
-#ifdef _MSC_VER
-#pragma optimize( "", on )
-#endif
-
-/// emitStubForFunction - This method is used by the JIT when it needs to emit
-/// the address of a function for a function whose code has not yet been
-/// generated. In order to do this, it generates a stub which jumps to the lazy
-/// function compiler, which will eventually get fixed to call the function
-/// directly.
-///
-unsigned JITResolver::emitStubForFunction(Function *F) {
- MCE.startFunctionStub(*F, 6);
- MCE.emitByte(0xE8); // Call with 32 bit pc-rel destination...
-
- unsigned Address = addFunctionReference(MCE.getCurrentPCValue(), F);
- MCE.emitWord(Address-MCE.getCurrentPCValue()-4);
-
- MCE.emitByte(0xCD); // Interrupt - Just a marker identifying the stub!
- return (intptr_t)MCE.finishFunctionStub(*F);
}
-
namespace {
class Emitter : public MachineFunctionPass {
const X86InstrInfo *II;
MachineCodeEmitter &MCE;
- std::map<const MachineBasicBlock*, unsigned> BasicBlockAddrs;
- std::vector<std::pair<const MachineBasicBlock *, unsigned> > BBRefs;
+ std::vector<std::pair<MachineBasicBlock *, unsigned> > BBRefs;
public:
explicit Emitter(MachineCodeEmitter &mce) : II(0), MCE(mce) {}
Emitter(MachineCodeEmitter &mce, const X86InstrInfo& ii)
void emitInstruction(const MachineInstr &MI);
private:
- void emitBasicBlock(const MachineBasicBlock &MBB);
-
- void emitPCRelativeBlockAddress(const MachineBasicBlock *BB);
+ void emitBasicBlock(MachineBasicBlock &MBB);
+ void emitPCRelativeBlockAddress(MachineBasicBlock *MBB);
void emitPCRelativeValue(unsigned Address);
- void emitGlobalAddressForCall(GlobalValue *GV);
+ void emitGlobalAddressForCall(GlobalValue *GV, bool isTailCall);
void emitGlobalAddressForPtr(GlobalValue *GV, int Disp = 0);
+ void emitExternalSymbolAddress(const char *ES, bool isPCRelative,
+ bool isTailCall);
void emitRegModRMByte(unsigned ModRMReg, unsigned RegOpcodeField);
void emitSIBByte(unsigned SS, unsigned Index, unsigned Base);
};
}
-// This function is required by X86AsmPrinter.cpp to work around GAS bugs
-void llvm::X86::emitInstruction(MachineCodeEmitter& mce,
- const X86InstrInfo& ii,
- const MachineInstr& mi)
-{
- Emitter(mce, ii).emitInstruction(mi);
-}
-
-/// addPassesToEmitMachineCode - Add passes to the specified pass manager to get
-/// machine code emitted. This uses a MachineCodeEmitter object to handle
-/// actually outputting the machine code and resolving things like the address
-/// of functions. This method should returns true if machine code emission is
-/// not supported.
-///
-bool X86TargetMachine::addPassesToEmitMachineCode(FunctionPassManager &PM,
- MachineCodeEmitter &MCE) {
- PM.add(new Emitter(MCE));
- // Delete machine code for this function
- PM.add(createMachineCodeDeleter());
- return false;
+/// createX86CodeEmitterPass - Return a pass that emits the collected X86 code
+/// to the specified MCE object.
+FunctionPass *llvm::createX86CodeEmitterPass(MachineCodeEmitter &MCE) {
+ return new Emitter(MCE);
}
bool Emitter::runOnMachineFunction(MachineFunction &MF) {
+ assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
+ MF.getTarget().getRelocationModel() != Reloc::Static) &&
+ "JIT relocation model must be set to static or default!");
II = ((X86TargetMachine&)MF.getTarget()).getInstrInfo();
- MCE.startFunction(MF);
- MCE.emitConstantPool(MF.getConstantPool());
- for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
- emitBasicBlock(*I);
- MCE.finishFunction(MF);
+ do {
+ BBRefs.clear();
+
+ MCE.startFunction(MF);
+ for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
+ emitBasicBlock(*I);
+ } while (MCE.finishFunction(MF));
- // Resolve all forward branches now...
+ // Resolve all forward branches now.
for (unsigned i = 0, e = BBRefs.size(); i != e; ++i) {
- unsigned Location = BasicBlockAddrs[BBRefs[i].first];
+ unsigned Location = MCE.getMachineBasicBlockAddress(BBRefs[i].first);
unsigned Ref = BBRefs[i].second;
- MCE.emitWordAt(Location-Ref-4, (unsigned*)(intptr_t)Ref);
+ *((unsigned*)(intptr_t)Ref) = Location-Ref-4;
}
BBRefs.clear();
- BasicBlockAddrs.clear();
return false;
}
-void Emitter::emitBasicBlock(const MachineBasicBlock &MBB) {
- if (uint64_t Addr = MCE.getCurrentPCValue())
- BasicBlockAddrs[&MBB] = Addr;
-
+void Emitter::emitBasicBlock(MachineBasicBlock &MBB) {
+ MCE.StartMachineBasicBlock(&MBB);
for (MachineBasicBlock::const_iterator I = MBB.begin(), E = MBB.end();
I != E; ++I)
emitInstruction(*I);
}
-/// emitPCRelativeBlockAddress - This method emits the PC relative address of
-/// the specified basic block, or if the basic block hasn't been emitted yet
-/// (because this is a forward branch), it keeps track of the information
-/// necessary to resolve this address later (and emits a dummy value).
+/// emitPCRelativeValue - Emit a 32-bit PC relative address.
///
-void Emitter::emitPCRelativeBlockAddress(const MachineBasicBlock *MBB) {
- // FIXME: Emit backward branches directly
- BBRefs.push_back(std::make_pair(MBB, MCE.getCurrentPCValue()));
- MCE.emitWord(0);
+void Emitter::emitPCRelativeValue(unsigned Address) {
+ MCE.emitWordLE(Address-MCE.getCurrentPCValue()-4);
}
-/// emitPCRelativeValue - Emit a 32-bit PC relative address.
+/// emitPCRelativeBlockAddress - This method keeps track of the information
+/// necessary to resolve the address of this block later and emits a dummy
+/// value.
///
-void Emitter::emitPCRelativeValue(unsigned Address) {
- MCE.emitWord(Address-MCE.getCurrentPCValue()-4);
+void Emitter::emitPCRelativeBlockAddress(MachineBasicBlock *MBB) {
+ // Remember where this reference was and where it is to so we can
+ // deal with it later.
+ BBRefs.push_back(std::make_pair(MBB, MCE.getCurrentPCValue()));
+ MCE.emitWordLE(0);
}
/// emitGlobalAddressForCall - Emit the specified address to the code stream
/// assuming this is part of a function call, which is PC relative.
///
-void Emitter::emitGlobalAddressForCall(GlobalValue *GV) {
- // Get the address from the backend...
- unsigned Address = MCE.getGlobalValueAddress(GV);
-
- if (Address == 0) {
- // FIXME: this is JIT specific!
- Address = getResolver(MCE).addFunctionReference(MCE.getCurrentPCValue(),
- cast<Function>(GV));
- }
- emitPCRelativeValue(Address);
+void Emitter::emitGlobalAddressForCall(GlobalValue *GV, bool isTailCall) {
+ MCE.addRelocation(MachineRelocation(MCE.getCurrentPCOffset(),
+ X86::reloc_pcrel_word, GV, 0,
+ !isTailCall /*Doesn'tNeedStub*/));
+ MCE.emitWordLE(0);
}
/// emitGlobalAddress - Emit the specified address to the code stream assuming
/// PC relative.
///
void Emitter::emitGlobalAddressForPtr(GlobalValue *GV, int Disp /* = 0 */) {
- // Get the address from the backend...
- unsigned Address = MCE.getGlobalValueAddress(GV);
-
- // If the machine code emitter doesn't know what the address IS yet, we have
- // to take special measures.
- //
- if (Address == 0) {
- // FIXME: this is JIT specific!
- Address = getResolver(MCE).getLazyResolver((Function*)GV);
- }
-
- MCE.emitWord(Address + Disp);
+ MCE.addRelocation(MachineRelocation(MCE.getCurrentPCOffset(),
+ X86::reloc_absolute_word, GV));
+ MCE.emitWordLE(Disp); // The relocated value will be added to the displacement
}
-
+/// emitExternalSymbolAddress - Arrange for the address of an external symbol to
+/// be emitted to the current location in the function, and allow it to be PC
+/// relative.
+void Emitter::emitExternalSymbolAddress(const char *ES, bool isPCRelative,
+ bool isTailCall) {
+ MCE.addRelocation(MachineRelocation(MCE.getCurrentPCOffset(),
+ isPCRelative ? X86::reloc_pcrel_word : X86::reloc_absolute_word, ES));
+ MCE.emitWordLE(0);
+}
/// N86 namespace - Native X86 Register numbers... used by X86 backend.
///
case X86::ST0: case X86::ST1: case X86::ST2: case X86::ST3:
case X86::ST4: case X86::ST5: case X86::ST6: case X86::ST7:
return RegNo-X86::ST0;
+
+ case X86::XMM0: case X86::XMM1: case X86::XMM2: case X86::XMM3:
+ case X86::XMM4: case X86::XMM5: case X86::XMM6: case X86::XMM7:
+ return RegNo-X86::XMM0;
+
default:
assert(MRegisterInfo::isVirtualRegister(RegNo) &&
"Unknown physical register!");
if (Op3.isGlobalAddress()) {
GV = Op3.getGlobal();
DispVal = Op3.getOffset();
+ } else if (Op3.isConstantPoolIndex()) {
+ DispVal += MCE.getConstantPoolEntryAddress(Op3.getConstantPoolIndex());
+ DispVal += Op3.getOffset();
+ } else if (Op3.isJumpTableIndex()) {
+ DispVal += MCE.getJumpTableEntryAddress(Op3.getJumpTableIndex());
} else {
DispVal = Op3.getImmedValue();
}
const MachineOperand &Scale = MI.getOperand(Op+1);
const MachineOperand &IndexReg = MI.getOperand(Op+2);
- unsigned BaseReg = 0;
-
- if (Base.isConstantPoolIndex()) {
- // Emit a direct address reference [disp32] where the displacement of the
- // constant pool entry is controlled by the MCE.
- assert(!GV && "Constant Pool reference cannot be relative to global!");
- DispVal += MCE.getConstantPoolEntryAddress(Base.getConstantPoolIndex());
- } else {
- BaseReg = Base.getReg();
- }
+ unsigned BaseReg = Base.getReg();
// Is a SIB byte needed?
if (IndexReg.getReg() == 0 && BaseReg != X86::ESP) {
// Emit the repeat opcode prefix as needed.
if ((Desc.TSFlags & X86II::Op0Mask) == X86II::REP) MCE.emitByte(0xF3);
- // Emit instruction prefixes if necessary
- if (Desc.TSFlags & X86II::OpSize) MCE.emitByte(0x66);// Operand size...
+ // Emit the operand size opcode prefix as needed.
+ if (Desc.TSFlags & X86II::OpSize) MCE.emitByte(0x66);
switch (Desc.TSFlags & X86II::Op0Mask) {
case X86II::TB:
MCE.emitByte(0x0F); // Two-byte opcode prefix
break;
case X86II::REP: break; // already handled.
+ case X86II::XS: // F3 0F
+ MCE.emitByte(0xF3);
+ MCE.emitByte(0x0F);
+ break;
+ case X86II::XD: // F2 0F
+ MCE.emitByte(0xF2);
+ MCE.emitByte(0x0F);
+ break;
case X86II::D8: case X86II::D9: case X86II::DA: case X86II::DB:
case X86II::DC: case X86II::DD: case X86II::DE: case X86II::DF:
MCE.emitByte(0xD8+
switch (Desc.TSFlags & X86II::FormMask) {
default: assert(0 && "Unknown FormMask value in X86 MachineCodeEmitter!");
case X86II::Pseudo:
- if (Opcode != X86::IMPLICIT_USE &&
- Opcode != X86::IMPLICIT_DEF &&
- Opcode != X86::FP_REG_KILL)
- std::cerr << "X86 Machine Code Emitter: No 'form', not emitting: " << MI;
+#ifndef NDEBUG
+ switch (Opcode) {
+ default:
+ assert(0 && "psuedo instructions should be removed before code emission");
+ case X86::IMPLICIT_USE:
+ case X86::IMPLICIT_DEF:
+ case X86::IMPLICIT_DEF_R8:
+ case X86::IMPLICIT_DEF_R16:
+ case X86::IMPLICIT_DEF_R32:
+ case X86::IMPLICIT_DEF_FR32:
+ case X86::IMPLICIT_DEF_FR64:
+ case X86::IMPLICIT_DEF_VR64:
+ case X86::IMPLICIT_DEF_VR128:
+ case X86::FP_REG_KILL:
+ break;
+ }
+#endif
break;
case X86II::RawFrm:
if (MO.isMachineBasicBlock()) {
emitPCRelativeBlockAddress(MO.getMachineBasicBlock());
} else if (MO.isGlobalAddress()) {
- assert(MO.isPCRelative() && "Call target is not PC Relative?");
- emitGlobalAddressForCall(MO.getGlobal());
+ bool isTailCall = Opcode == X86::TAILJMPd ||
+ Opcode == X86::TAILJMPr || Opcode == X86::TAILJMPm;
+ emitGlobalAddressForCall(MO.getGlobal(), isTailCall);
} else if (MO.isExternalSymbol()) {
- unsigned Address = MCE.getGlobalValueAddress(MO.getSymbolName());
- assert(Address && "Unknown external symbol!");
- emitPCRelativeValue(Address);
+ bool isTailCall = Opcode == X86::TAILJMPd ||
+ Opcode == X86::TAILJMPr || Opcode == X86::TAILJMPm;
+ emitExternalSymbolAddress(MO.getSymbolName(), true, isTailCall);
} else if (MO.isImmediate()) {
- emitConstant(MO.getImmedValue(), sizeOfImm(Desc));
+ emitConstant(MO.getImmedValue(), sizeOfImm(Desc));
} else {
assert(0 && "Unknown RawFrm operand!");
}
} else if (MO1.isExternalSymbol()) {
assert(sizeOfImm(Desc) == 4 &&
"Don't know how to emit non-pointer values!");
- unsigned Address = MCE.getGlobalValueAddress(MO1.getSymbolName());
- assert(Address && "Unknown external symbol!");
- MCE.emitWord(Address);
+ emitExternalSymbolAddress(MO1.getSymbolName(), false, false);
+ } else if (MO1.isJumpTableIndex()) {
+ assert(sizeOfImm(Desc) == 4 &&
+ "Don't know how to emit non-pointer values!");
+ emitConstant(MCE.getJumpTableEntryAddress(MO1.getJumpTableIndex()), 4);
} else {
emitConstant(MO1.getImmedValue(), sizeOfImm(Desc));
}
case X86II::MRMSrcReg:
MCE.emitByte(BaseOpcode);
-
emitRegModRMByte(MI.getOperand(1).getReg(),
getX86RegNum(MI.getOperand(0).getReg()));
if (MI.getNumOperands() == 3)
(Desc.TSFlags & X86II::FormMask)-X86II::MRM0r);
if (MI.getOperand(MI.getNumOperands()-1).isImmediate()) {
- emitConstant(MI.getOperand(MI.getNumOperands()-1).getImmedValue(), sizeOfImm(Desc));
+ emitConstant(MI.getOperand(MI.getNumOperands()-1).getImmedValue(),
+ sizeOfImm(Desc));
}
break;
case X86II::MRM0m: case X86II::MRM1m:
case X86II::MRM2m: case X86II::MRM3m:
case X86II::MRM4m: case X86II::MRM5m:
- case X86II::MRM6m: case X86II::MRM7m:
+ case X86II::MRM6m: case X86II::MRM7m:
MCE.emitByte(BaseOpcode);
emitMemModRMByte(MI, 0, (Desc.TSFlags & X86II::FormMask)-X86II::MRM0m);
else if (MI.getOperand(4).isGlobalAddress())
emitGlobalAddressForPtr(MI.getOperand(4).getGlobal(),
MI.getOperand(4).getOffset());
+ else if (MI.getOperand(4).isJumpTableIndex())
+ emitConstant(MCE.getJumpTableEntryAddress(MI.getOperand(4)
+ .getJumpTableIndex()), 4);
else
assert(0 && "Unknown operand!");
}
break;
+
+ case X86II::MRMInitReg:
+ MCE.emitByte(BaseOpcode);
+ emitRegModRMByte(MI.getOperand(0).getReg(),
+ getX86RegNum(MI.getOperand(0).getReg()));
+ break;
}
}
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