llvm-6502/lib/Target/ARM/ARMTargetMachine.cpp
Evan Cheng d847124211 Thumb2 IT blocks are fairly expensive. When there are multiple selects using
the same condition, it's important to make sure they are scheduled together
to avoid forming multiple IT blocks. I'm adding a pre-regalloc pass that forms
IT blocks early (by re-scheduling instructions and split basic blocks) to
attempt to fix this. This is not turned on by default since I am not sure this
is the right fix.

Another issue is llvm selects are modeled as two-address conditional moves.
This can be very bad when the copies before the conditional moves are not
coalesced away. Teach IT formation pass to move the copies above the IT block
(when legal) to avoid breaking the IT block.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105669 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-09 01:46:50 +00:00

159 lines
5.3 KiB
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//===-- ARMTargetMachine.cpp - Define TargetMachine for ARM ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
#include "ARMTargetMachine.h"
#include "ARMMCAsmInfo.h"
#include "ARMFrameInfo.h"
#include "ARM.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegistry.h"
using namespace llvm;
static cl::opt<bool>
EarlyITBlockFormation("thumb2-early-it-blocks", cl::Hidden,
cl::desc("Form IT blocks earlt, before register allocation"),
cl::init(false));
static MCAsmInfo *createMCAsmInfo(const Target &T, StringRef TT) {
Triple TheTriple(TT);
switch (TheTriple.getOS()) {
case Triple::Darwin:
return new ARMMCAsmInfoDarwin();
default:
return new ARMELFMCAsmInfo();
}
}
extern "C" void LLVMInitializeARMTarget() {
// Register the target.
RegisterTargetMachine<ARMTargetMachine> X(TheARMTarget);
RegisterTargetMachine<ThumbTargetMachine> Y(TheThumbTarget);
// Register the target asm info.
RegisterAsmInfoFn A(TheARMTarget, createMCAsmInfo);
RegisterAsmInfoFn B(TheThumbTarget, createMCAsmInfo);
}
/// TargetMachine ctor - Create an ARM architecture model.
///
ARMBaseTargetMachine::ARMBaseTargetMachine(const Target &T,
const std::string &TT,
const std::string &FS,
bool isThumb)
: LLVMTargetMachine(T, TT),
Subtarget(TT, FS, isThumb),
FrameInfo(Subtarget),
JITInfo(),
InstrItins(Subtarget.getInstrItineraryData()) {
DefRelocModel = getRelocationModel();
}
ARMTargetMachine::ARMTargetMachine(const Target &T, const std::string &TT,
const std::string &FS)
: ARMBaseTargetMachine(T, TT, FS, false), InstrInfo(Subtarget),
DataLayout(Subtarget.isAPCS_ABI() ?
std::string("e-p:32:32-f64:32:32-i64:32:32-n32") :
std::string("e-p:32:32-f64:64:64-i64:64:64-n32")),
TLInfo(*this),
TSInfo(*this) {
}
ThumbTargetMachine::ThumbTargetMachine(const Target &T, const std::string &TT,
const std::string &FS)
: ARMBaseTargetMachine(T, TT, FS, true),
InstrInfo(Subtarget.hasThumb2()
? ((ARMBaseInstrInfo*)new Thumb2InstrInfo(Subtarget))
: ((ARMBaseInstrInfo*)new Thumb1InstrInfo(Subtarget))),
DataLayout(Subtarget.isAPCS_ABI() ?
std::string("e-p:32:32-f64:32:32-i64:32:32-"
"i16:16:32-i8:8:32-i1:8:32-a:0:32-n32") :
std::string("e-p:32:32-f64:64:64-i64:64:64-"
"i16:16:32-i8:8:32-i1:8:32-a:0:32-n32")),
TLInfo(*this),
TSInfo(*this) {
}
// Pass Pipeline Configuration
bool ARMBaseTargetMachine::addInstSelector(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
PM.add(createARMISelDag(*this, OptLevel));
return false;
}
bool ARMBaseTargetMachine::addPreRegAlloc(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
if (Subtarget.hasNEON())
PM.add(createNEONPreAllocPass());
// FIXME: temporarily disabling load / store optimization pass for Thumb1.
if (OptLevel != CodeGenOpt::None && !Subtarget.isThumb1Only())
PM.add(createARMLoadStoreOptimizationPass(true));
if (OptLevel != CodeGenOpt::None && Subtarget.isThumb2() &&
EarlyITBlockFormation)
PM.add(createThumb2ITBlockPass(true));
return true;
}
bool ARMBaseTargetMachine::addPreSched2(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
// FIXME: temporarily disabling load / store optimization pass for Thumb1.
if (OptLevel != CodeGenOpt::None) {
if (!Subtarget.isThumb1Only())
PM.add(createARMLoadStoreOptimizationPass());
if (Subtarget.hasNEON())
PM.add(createNEONMoveFixPass());
}
// Expand some pseudo instructions into multiple instructions to allow
// proper scheduling.
PM.add(createARMExpandPseudoPass());
return true;
}
bool ARMBaseTargetMachine::addPreEmitPass(PassManagerBase &PM,
CodeGenOpt::Level OptLevel) {
// FIXME: temporarily disabling load / store optimization pass for Thumb1.
if (OptLevel != CodeGenOpt::None) {
if (!Subtarget.isThumb1Only())
PM.add(createIfConverterPass());
}
if (Subtarget.isThumb2()) {
PM.add(createThumb2ITBlockPass());
PM.add(createThumb2SizeReductionPass());
}
PM.add(createARMConstantIslandPass());
return true;
}
bool ARMBaseTargetMachine::addCodeEmitter(PassManagerBase &PM,
CodeGenOpt::Level OptLevel,
JITCodeEmitter &JCE) {
// FIXME: Move this to TargetJITInfo!
if (DefRelocModel == Reloc::Default)
setRelocationModel(Reloc::Static);
// Machine code emitter pass for ARM.
PM.add(createARMJITCodeEmitterPass(*this, JCE));
return false;
}