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//===-- ARMSubtarget.cpp - ARM Subtarget Information ------------*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file implements the ARM specific subclass of TargetSubtarget.
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//===----------------------------------------------------------------------===//
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#include "ARMSubtarget.h"
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#include "ARMGenSubtarget.inc"
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#include "llvm/GlobalValue.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/ADT/SmallVector.h"
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ReserveR9("arm-reserve-r9", cl::Hidden,
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cl::desc("Reserve R9, making it unavailable as GPR"));
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UseNEONFP("arm-use-neon-fp",
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cl::desc("Use NEON for single-precision FP"),
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cl::init(false), cl::Hidden);
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UseMOVT("arm-use-movt",
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cl::init(true), cl::Hidden);
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ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &FS,
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, UseNEONForSinglePrecisionFP(UseNEONFP)
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, PostRAScheduler(false)
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, IsR9Reserved(ReserveR9)
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, CPUString("generic")
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, TargetType(isELF) // Default to ELF unless otherwise specified.
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, TargetABI(ARM_ABI_APCS) {
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// default to soft float ABI
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if (FloatABIType == FloatABI::Default)
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FloatABIType = FloatABI::Soft;
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// Determine default and user specified characteristics
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// Parse features string.
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CPUString = ParseSubtargetFeatures(FS, CPUString);
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// Set the boolean corresponding to the current target triple, or the default
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// if one cannot be determined, to true.
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unsigned Len = TT.length();
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if (Len >= 5 && TT.substr(0, 4) == "armv")
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else if (Len >= 6 && TT.substr(0, 5) == "thumb") {
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if (Len >= 7 && TT[5] == 'v')
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unsigned SubVer = TT[Idx];
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if (SubVer > '4' && SubVer <= '9') {
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} else if (SubVer == '6') {
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if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
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ARMArchVersion = V6T2;
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} else if (SubVer == '5') {
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if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
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ARMArchVersion = V5TE;
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if (ARMArchVersion >= V6T2)
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// Thumb2 implies at least V6T2.
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if (ARMArchVersion < V6T2 && ThumbMode >= Thumb2)
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ARMArchVersion = V6T2;
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if (TT.find("-darwin") != std::string::npos)
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TargetType = isDarwin;
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if (TT.find("eabi") != std::string::npos)
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TargetABI = ARM_ABI_AAPCS;
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if (isTargetDarwin())
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IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);
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if (!isThumb() || hasThumb2())
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PostRAScheduler = true;
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// Set CPU specific features.
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if (CPUString == "cortex-a8") {
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// On Cortex-a8, it's faster to perform some single-precision FP
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// operations with NEON instructions.
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if (UseNEONFP.getPosition() == 0)
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UseNEONForSinglePrecisionFP = true;
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/// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.
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ARMSubtarget::GVIsIndirectSymbol(GlobalValue *GV, Reloc::Model RelocM) const {
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if (RelocM == Reloc::Static)
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// Materializable GVs (in JIT lazy compilation mode) do not require an extra
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bool isDecl = GV->isDeclaration() && !GV->isMaterializable();
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if (!isTargetDarwin()) {
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// Extra load is needed for all externally visible.
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if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
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if (RelocM == Reloc::PIC_) {
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// If this is a strong reference to a definition, it is definitely not
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if (!isDecl && !GV->isWeakForLinker())
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// Unless we have a symbol with hidden visibility, we have to go through a
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// normal $non_lazy_ptr stub because this symbol might be resolved late.
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if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
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// If symbol visibility is hidden, we have a stub for common symbol
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// references and external declarations.
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if (isDecl || GV->hasCommonLinkage())
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// Hidden $non_lazy_ptr reference.
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// If this is a strong reference to a definition, it is definitely not
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if (!isDecl && !GV->isWeakForLinker())
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// Unless we have a symbol with hidden visibility, we have to go through a
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// normal $non_lazy_ptr stub because this symbol might be resolved late.
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if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
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bool ARMSubtarget::enablePostRAScheduler(
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CodeGenOpt::Level OptLevel,
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TargetSubtarget::AntiDepBreakMode& Mode,
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RegClassVector& CriticalPathRCs) const {
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Mode = TargetSubtarget::ANTIDEP_CRITICAL;
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CriticalPathRCs.clear();
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CriticalPathRCs.push_back(&ARM::GPRRegClass);
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return PostRAScheduler && OptLevel >= CodeGenOpt::Default;