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//===-- ARMSubtarget.cpp - ARM Subtarget Information ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the ARM specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//
#include "ARMSubtarget.h"
#include "ARMBaseInstrInfo.h"
#include "ARMBaseRegisterInfo.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetOptions.h"
#define GET_SUBTARGETINFO_TARGET_DESC
#define GET_SUBTARGETINFO_CTOR
#include "ARMGenSubtargetInfo.inc"
using namespace llvm;
static cl::opt<bool>
ReserveR9("arm-reserve-r9", cl::Hidden,
cl::desc("Reserve R9, making it unavailable as GPR"));
static cl::opt<bool>
DarwinUseMOVT("arm-darwin-use-movt", cl::init(true), cl::Hidden);
static cl::opt<bool>
UseFusedMulOps("arm-use-mulops",
cl::init(true), cl::Hidden);
static cl::opt<bool>
StrictAlign("arm-strict-align", cl::Hidden,
cl::desc("Disallow all unaligned memory accesses"));
ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &CPU,
const std::string &FS, const TargetOptions &Options)
: ARMGenSubtargetInfo(TT, CPU, FS)
, ARMProcFamily(Others)
, stackAlignment(4)
, CPUString(CPU)
, TargetTriple(TT)
, Options(Options)
, TargetABI(ARM_ABI_APCS) {
initializeEnvironment();
resetSubtargetFeatures(CPU, FS);
}
void ARMSubtarget::initializeEnvironment() {
HasV4TOps = false;
HasV5TOps = false;
HasV5TEOps = false;
HasV6Ops = false;
HasV6T2Ops = false;
HasV7Ops = false;
HasVFPv2 = false;
HasVFPv3 = false;
HasVFPv4 = false;
HasNEON = false;
UseNEONForSinglePrecisionFP = false;
UseMulOps = UseFusedMulOps;
SlowFPVMLx = false;
HasVMLxForwarding = false;
SlowFPBrcc = false;
InThumbMode = false;
HasThumb2 = false;
IsMClass = false;
NoARM = false;
PostRAScheduler = false;
IsR9Reserved = ReserveR9;
UseMovt = false;
SupportsTailCall = false;
HasFP16 = false;
HasD16 = false;
HasHardwareDivide = false;
HasHardwareDivideInARM = false;
HasT2ExtractPack = false;
HasDataBarrier = false;
Pref32BitThumb = false;
AvoidCPSRPartialUpdate = false;
AvoidMOVsShifterOperand = false;
HasRAS = false;
HasMPExtension = false;
FPOnlySP = false;
AllowsUnalignedMem = false;
Thumb2DSP = false;
UseNaClTrap = false;
UnsafeFPMath = false;
}
void ARMSubtarget::resetSubtargetFeatures(const MachineFunction *MF) {
AttributeSet FnAttrs = MF->getFunction()->getAttributes();
Attribute CPUAttr = FnAttrs.getAttribute(AttributeSet::FunctionIndex,
"target-cpu");
Attribute FSAttr = FnAttrs.getAttribute(AttributeSet::FunctionIndex,
"target-features");
std::string CPU =
!CPUAttr.hasAttribute(Attribute::None) ?CPUAttr.getValueAsString() : "";
std::string FS =
!FSAttr.hasAttribute(Attribute::None) ? FSAttr.getValueAsString() : "";
if (!FS.empty()) {
initializeEnvironment();
resetSubtargetFeatures(CPU, FS);
}
}
void ARMSubtarget::resetSubtargetFeatures(StringRef CPU, StringRef FS) {
if (CPUString.empty())
CPUString = "generic";
// Insert the architecture feature derived from the target triple into the
// feature string. This is important for setting features that are implied
// based on the architecture version.
std::string ArchFS = ARM_MC::ParseARMTriple(TargetTriple.getTriple(),
CPUString);
if (!FS.empty()) {
if (!ArchFS.empty())
ArchFS = ArchFS + "," + FS.str();
else
ArchFS = FS;
}
ParseSubtargetFeatures(CPUString, ArchFS);
// Thumb2 implies at least V6T2. FIXME: Fix tests to explicitly specify a
// ARM version or CPU and then remove this.
if (!HasV6T2Ops && hasThumb2())
HasV4TOps = HasV5TOps = HasV5TEOps = HasV6Ops = HasV6T2Ops = true;
// Keep a pointer to static instruction cost data for the specified CPU.
SchedModel = getSchedModelForCPU(CPUString);
// Initialize scheduling itinerary for the specified CPU.
InstrItins = getInstrItineraryForCPU(CPUString);
if ((TargetTriple.getTriple().find("eabi") != std::string::npos) ||
(isTargetIOS() && isMClass()))
// FIXME: We might want to separate AAPCS and EABI. Some systems, e.g.
// Darwin-EABI conforms to AACPS but not the rest of EABI.
TargetABI = ARM_ABI_AAPCS;
if (isAAPCS_ABI())
stackAlignment = 8;
if (!isTargetIOS())
UseMovt = hasV6T2Ops();
else {
IsR9Reserved = ReserveR9 | !HasV6Ops;
UseMovt = DarwinUseMOVT && hasV6T2Ops();
SupportsTailCall = !getTargetTriple().isOSVersionLT(5, 0);
}
if (!isThumb() || hasThumb2())
PostRAScheduler = true;
// v6+ may or may not support unaligned mem access depending on the system
// configuration.
if (!StrictAlign && hasV6Ops() && isTargetDarwin())
AllowsUnalignedMem = true;
// NEON f32 ops are non-IEEE 754 compliant. Darwin is ok with it by default.
uint64_t Bits = getFeatureBits();
if ((Bits & ARM::ProcA5 || Bits & ARM::ProcA8) && // Where this matters
(Options.UnsafeFPMath || isTargetDarwin()))
UseNEONForSinglePrecisionFP = true;
}
/// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.
bool
ARMSubtarget::GVIsIndirectSymbol(const GlobalValue *GV,
Reloc::Model RelocM) const {
if (RelocM == Reloc::Static)
return false;
// Materializable GVs (in JIT lazy compilation mode) do not require an extra
// load from stub.
bool isDecl = GV->hasAvailableExternallyLinkage();
if (GV->isDeclaration() && !GV->isMaterializable())
isDecl = true;
if (!isTargetDarwin()) {
// Extra load is needed for all externally visible.
if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
return false;
return true;
} else {
if (RelocM == Reloc::PIC_) {
// If this is a strong reference to a definition, it is definitely not
// through a stub.
if (!isDecl && !GV->isWeakForLinker())
return false;
// Unless we have a symbol with hidden visibility, we have to go through a
// normal $non_lazy_ptr stub because this symbol might be resolved late.
if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
return true;
// If symbol visibility is hidden, we have a stub for common symbol
// references and external declarations.
if (isDecl || GV->hasCommonLinkage())
// Hidden $non_lazy_ptr reference.
return true;
return false;
} else {
// If this is a strong reference to a definition, it is definitely not
// through a stub.
if (!isDecl && !GV->isWeakForLinker())
return false;
// Unless we have a symbol with hidden visibility, we have to go through a
// normal $non_lazy_ptr stub because this symbol might be resolved late.
if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
return true;
}
}
return false;
}
unsigned ARMSubtarget::getMispredictionPenalty() const {
return SchedModel->MispredictPenalty;
}
bool ARMSubtarget::enablePostRAScheduler(
CodeGenOpt::Level OptLevel,
TargetSubtargetInfo::AntiDepBreakMode& Mode,
RegClassVector& CriticalPathRCs) const {
Mode = TargetSubtargetInfo::ANTIDEP_CRITICAL;
CriticalPathRCs.clear();
CriticalPathRCs.push_back(&ARM::GPRRegClass);
return PostRAScheduler && OptLevel >= CodeGenOpt::Default;
}
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