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//===-- ARMSubtarget.cpp - ARM Subtarget Information ------------*- C++ -*-===//
//
// 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 TargetSubtarget.
//
//===----------------------------------------------------------------------===//
#include "ARMSubtarget.h"
#include "ARMGenSubtarget.inc"
#include "llvm/GlobalValue.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/ADT/SmallVector.h"
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>
UseNEONFP("arm-use-neon-fp",
cl::desc("Use NEON for single-precision FP"),
cl::init(false), cl::Hidden);
ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &FS,
bool isT)
: ARMArchVersion(V4T)
, ARMFPUType(None)
, UseNEONForSinglePrecisionFP(UseNEONFP)
, IsThumb(isT)
, ThumbMode(Thumb1)
, PostRAScheduler(false)
, IsR9Reserved(ReserveR9)
, stackAlignment(4)
, CPUString("generic")
, TargetType(isELF) // Default to ELF unless otherwise specified.
, TargetABI(ARM_ABI_APCS) {
// default to soft float ABI
if (FloatABIType == FloatABI::Default)
FloatABIType = FloatABI::Soft;
// Determine default and user specified characteristics
// Parse features string.
CPUString = ParseSubtargetFeatures(FS, CPUString);
// Set the boolean corresponding to the current target triple, or the default
// if one cannot be determined, to true.
unsigned Len = TT.length();
unsigned Idx = 0;
if (Len >= 5 && TT.substr(0, 4) == "armv")
Idx = 4;
else if (Len >= 6 && TT.substr(0, 5) == "thumb") {
IsThumb = true;
if (Len >= 7 && TT[5] == 'v')
Idx = 6;
}
if (Idx) {
unsigned SubVer = TT[Idx];
if (SubVer > '4' && SubVer <= '9') {
if (SubVer >= '7') {
ARMArchVersion = V7A;
} else if (SubVer == '6') {
ARMArchVersion = V6;
if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
ARMArchVersion = V6T2;
} else if (SubVer == '5') {
ARMArchVersion = V5T;
if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
ARMArchVersion = V5TE;
}
if (ARMArchVersion >= V6T2)
ThumbMode = Thumb2;
}
}
// Thumb2 implies at least V6T2.
if (ARMArchVersion < V6T2 && ThumbMode >= Thumb2)
ARMArchVersion = V6T2;
if (Len >= 10) {
if (TT.find("-darwin") != std::string::npos)
// arm-darwin
TargetType = isDarwin;
}
if (TT.find("eabi") != std::string::npos)
TargetABI = ARM_ABI_AAPCS;
if (isAAPCS_ABI())
stackAlignment = 8;
if (isTargetDarwin())
IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);
if (!isThumb() || hasThumb2())
PostRAScheduler = true;
// Set CPU specific features.
if (CPUString == "cortex-a8") {
// On Cortex-a8, it's faster to perform some single-precision FP
// operations with NEON instructions.
if (UseNEONFP.getPosition() == 0)
UseNEONForSinglePrecisionFP = true;
}
}
/// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.
bool
ARMSubtarget::GVIsIndirectSymbol(GlobalValue *GV, Reloc::Model RelocM) const {
if (RelocM == Reloc::Static)
return false;
// GV with ghost linkage (in JIT lazy compilation mode) do not require an
// extra load from stub.
bool isDecl = GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode();
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;
}
bool ARMSubtarget::enablePostRAScheduler(
CodeGenOpt::Level OptLevel,
TargetSubtarget::AntiDepBreakMode& Mode,
ExcludedRCVector& ExcludedRCs) const {
Mode = TargetSubtarget::ANTIDEP_CRITICAL;
ExcludedRCs.clear();
ExcludedRCs.push_back(&ARM::GPRRegClass);
return PostRAScheduler && OptLevel >= CodeGenOpt::Default;
}
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