llvm-6502/lib/Target/X86/X86TargetMachine.cpp
Jeffrey Yasskin d1ba06bf13 Make X86-64 in the Large model always emit 64-bit calls.
The large code model is documented at
http://www.x86-64.org/documentation/abi.pdf and says that calls should
assume their target doesn't live within the 32-bit pc-relative offset
that fits in the call instruction.

To do this, we turn off the global-address->target-global-address
conversion in X86TargetLowering::LowerCall(). The first attempt at
this broke the lazy JIT because it can separate the movabs(imm->reg)
from the actual call instruction. The lazy JIT receives the address of
the movabs as a relocation and needs to record the return address from
the call; and then when that call happens, it needs to patch the
movabs with the newly-compiled target. We could thread the call
instruction into the relocation and record the movabs<->call mapping
explicitly, but that seems to require at least as much new
complication in the code generator as this change.

To fix this, we make lazy functions _always_ go through a call
stub. You'd think we'd only have to force lazy calls through a stub on
difficult platforms, but that turns out to break indirect calls
through a function pointer. The right fix for that is to distinguish
between calls and address-of operations on uncompiled functions, but
that's complex enough to leave for someone else to do.

Another attempt at this defined a new CALL64i pseudo-instruction,
which expanded to a 2-instruction sequence in the assembly output and
was special-cased in the X86CodeEmitter's emitInstruction()
function. That broke indirect calls in the same way as above.

This patch also removes a hack forcing Darwin to the small code model.
Without far-call-stubs, the small code model requires things of the
JITMemoryManager that the DefaultJITMemoryManager can't provide.

Thanks to echristo for lots of testing!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88984 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-16 22:41:33 +00:00

243 lines
8.7 KiB
C++

//===-- X86TargetMachine.cpp - Define TargetMachine for the X86 -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the X86 specific subclass of TargetMachine.
//
//===----------------------------------------------------------------------===//
#include "X86MCAsmInfo.h"
#include "X86TargetMachine.h"
#include "X86.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegistry.h"
using namespace llvm;
static const MCAsmInfo *createMCAsmInfo(const Target &T, StringRef TT) {
Triple TheTriple(TT);
switch (TheTriple.getOS()) {
case Triple::Darwin:
return new X86MCAsmInfoDarwin(TheTriple);
case Triple::MinGW32:
case Triple::MinGW64:
case Triple::Cygwin:
return new X86MCAsmInfoCOFF(TheTriple);
case Triple::Win32:
return new X86WinMCAsmInfo(TheTriple);
default:
return new X86ELFMCAsmInfo(TheTriple);
}
}
extern "C" void LLVMInitializeX86Target() {
// Register the target.
RegisterTargetMachine<X86_32TargetMachine> X(TheX86_32Target);
RegisterTargetMachine<X86_64TargetMachine> Y(TheX86_64Target);
// Register the target asm info.
RegisterAsmInfoFn A(TheX86_32Target, createMCAsmInfo);
RegisterAsmInfoFn B(TheX86_64Target, createMCAsmInfo);
// Register the code emitter.
TargetRegistry::RegisterCodeEmitter(TheX86_32Target, createX86MCCodeEmitter);
TargetRegistry::RegisterCodeEmitter(TheX86_64Target, createX86MCCodeEmitter);
}
X86_32TargetMachine::X86_32TargetMachine(const Target &T, const std::string &TT,
const std::string &FS)
: X86TargetMachine(T, TT, FS, false) {
}
X86_64TargetMachine::X86_64TargetMachine(const Target &T, const std::string &TT,
const std::string &FS)
: X86TargetMachine(T, TT, FS, true) {
}
/// X86TargetMachine ctor - Create an X86 target.
///
X86TargetMachine::X86TargetMachine(const Target &T, const std::string &TT,
const std::string &FS, bool is64Bit)
: LLVMTargetMachine(T, TT),
Subtarget(TT, FS, is64Bit),
DataLayout(Subtarget.getDataLayout()),
FrameInfo(TargetFrameInfo::StackGrowsDown,
Subtarget.getStackAlignment(),
(Subtarget.isTargetWin64() ? -40 :
(Subtarget.is64Bit() ? -8 : -4))),
InstrInfo(*this), JITInfo(*this), TLInfo(*this), ELFWriterInfo(*this) {
DefRelocModel = getRelocationModel();
// If no relocation model was picked, default as appropriate for the target.
if (getRelocationModel() == Reloc::Default) {
if (!Subtarget.isTargetDarwin())
setRelocationModel(Reloc::Static);
else if (Subtarget.is64Bit())
setRelocationModel(Reloc::PIC_);
else
setRelocationModel(Reloc::DynamicNoPIC);
}
assert(getRelocationModel() != Reloc::Default &&
"Relocation mode not picked");
// If no code model is picked, default to small.
if (getCodeModel() == CodeModel::Default)
setCodeModel(CodeModel::Small);
// ELF and X86-64 don't have a distinct DynamicNoPIC model. DynamicNoPIC
// is defined as a model for code which may be used in static or dynamic
// executables but not necessarily a shared library. On X86-32 we just
// compile in -static mode, in x86-64 we use PIC.
if (getRelocationModel() == Reloc::DynamicNoPIC) {
if (is64Bit)
setRelocationModel(Reloc::PIC_);
else if (!Subtarget.isTargetDarwin())
setRelocationModel(Reloc::Static);
}
// If we are on Darwin, disallow static relocation model in X86-64 mode, since
// the Mach-O file format doesn't support it.
if (getRelocationModel() == Reloc::Static &&
Subtarget.isTargetDarwin() &&
is64Bit)
setRelocationModel(Reloc::PIC_);
// Determine the PICStyle based on the target selected.
if (getRelocationModel() == Reloc::Static) {
// Unless we're in PIC or DynamicNoPIC mode, set the PIC style to None.
Subtarget.setPICStyle(PICStyles::None);
} else if (Subtarget.isTargetCygMing()) {
Subtarget.setPICStyle(PICStyles::None);
} else if (Subtarget.isTargetDarwin()) {
if (Subtarget.is64Bit())
Subtarget.setPICStyle(PICStyles::RIPRel);
else if (getRelocationModel() == Reloc::PIC_)
Subtarget.setPICStyle(PICStyles::StubPIC);
else {
assert(getRelocationModel() == Reloc::DynamicNoPIC);
Subtarget.setPICStyle(PICStyles::StubDynamicNoPIC);
}
} else if (Subtarget.isTargetELF()) {
if (Subtarget.is64Bit())
Subtarget.setPICStyle(PICStyles::RIPRel);
else
Subtarget.setPICStyle(PICStyles::GOT);
}
// Finally, if we have "none" as our PIC style, force to static mode.
if (Subtarget.getPICStyle() == PICStyles::None)
setRelocationModel(Reloc::Static);
}
//===----------------------------------------------------------------------===//
// Pass Pipeline Configuration
//===----------------------------------------------------------------------===//
bool X86TargetMachine::addInstSelector(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
// Install an instruction selector.
PM.add(createX86ISelDag(*this, OptLevel));
// If we're using Fast-ISel, clean up the mess.
if (EnableFastISel)
PM.add(createDeadMachineInstructionElimPass());
// Install a pass to insert x87 FP_REG_KILL instructions, as needed.
PM.add(createX87FPRegKillInserterPass());
return false;
}
bool X86TargetMachine::addPreRegAlloc(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
// Calculate and set max stack object alignment early, so we can decide
// whether we will need stack realignment (and thus FP).
PM.add(createX86MaxStackAlignmentCalculatorPass());
return false; // -print-machineinstr shouldn't print after this.
}
bool X86TargetMachine::addPostRegAlloc(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
PM.add(createX86FloatingPointStackifierPass());
return true; // -print-machineinstr should print after this.
}
bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
CodeGenOpt::Level OptLevel,
MachineCodeEmitter &MCE) {
// FIXME: Move this to TargetJITInfo!
// On Darwin, do not override 64-bit setting made in X86TargetMachine().
if (DefRelocModel == Reloc::Default &&
(!Subtarget.isTargetDarwin() || !Subtarget.is64Bit())) {
setRelocationModel(Reloc::Static);
Subtarget.setPICStyle(PICStyles::None);
}
// 64-bit JIT places everything in the same buffer except external functions.
if (Subtarget.is64Bit())
setCodeModel(CodeModel::Large);
PM.add(createX86CodeEmitterPass(*this, MCE));
return false;
}
bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
CodeGenOpt::Level OptLevel,
JITCodeEmitter &JCE) {
// FIXME: Move this to TargetJITInfo!
// On Darwin, do not override 64-bit setting made in X86TargetMachine().
if (DefRelocModel == Reloc::Default &&
(!Subtarget.isTargetDarwin() || !Subtarget.is64Bit())) {
setRelocationModel(Reloc::Static);
Subtarget.setPICStyle(PICStyles::None);
}
// 64-bit JIT places everything in the same buffer except external functions.
if (Subtarget.is64Bit())
setCodeModel(CodeModel::Large);
PM.add(createX86JITCodeEmitterPass(*this, JCE));
return false;
}
bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
CodeGenOpt::Level OptLevel,
ObjectCodeEmitter &OCE) {
PM.add(createX86ObjectCodeEmitterPass(*this, OCE));
return false;
}
bool X86TargetMachine::addSimpleCodeEmitter(PassManagerBase &PM,
CodeGenOpt::Level OptLevel,
MachineCodeEmitter &MCE) {
PM.add(createX86CodeEmitterPass(*this, MCE));
return false;
}
bool X86TargetMachine::addSimpleCodeEmitter(PassManagerBase &PM,
CodeGenOpt::Level OptLevel,
JITCodeEmitter &JCE) {
PM.add(createX86JITCodeEmitterPass(*this, JCE));
return false;
}
bool X86TargetMachine::addSimpleCodeEmitter(PassManagerBase &PM,
CodeGenOpt::Level OptLevel,
ObjectCodeEmitter &OCE) {
PM.add(createX86ObjectCodeEmitterPass(*this, OCE));
return false;
}