1 //===-- ARMSubtarget.cpp - ARM Subtarget Information ------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the ARM specific subclass of TargetSubtarget.
12 //===----------------------------------------------------------------------===//
14 #include "ARMSubtarget.h"
15 #include "ARMGenSubtarget.inc"
16 #include "llvm/GlobalValue.h"
17 #include "llvm/Target/TargetOptions.h"
18 #include "llvm/Support/CommandLine.h"
19 #include "llvm/ADT/SmallVector.h"
23 ReserveR9("arm-reserve-r9", cl::Hidden,
24 cl::desc("Reserve R9, making it unavailable as GPR"));
26 UseNEONFP("arm-use-neon-fp",
27 cl::desc("Use NEON for single-precision FP"),
28 cl::init(false), cl::Hidden);
31 UseMOVT("arm-use-movt",
32 cl::init(true), cl::Hidden);
34 ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &FS,
38 , UseNEONForSinglePrecisionFP(UseNEONFP)
41 , PostRAScheduler(false)
42 , IsR9Reserved(ReserveR9)
45 , CPUString("generic")
46 , TargetType(isELF) // Default to ELF unless otherwise specified.
47 , TargetABI(ARM_ABI_APCS) {
48 // default to soft float ABI
49 if (FloatABIType == FloatABI::Default)
50 FloatABIType = FloatABI::Soft;
52 // Determine default and user specified characteristics
54 // Parse features string.
55 CPUString = ParseSubtargetFeatures(FS, CPUString);
57 // When no arch is specified either by CPU or by attributes, make the default
59 if (CPUString == "generic" && (FS.empty() || FS == "generic"))
62 // Set the boolean corresponding to the current target triple, or the default
63 // if one cannot be determined, to true.
64 unsigned Len = TT.length();
67 if (Len >= 5 && TT.substr(0, 4) == "armv")
69 else if (Len >= 6 && TT.substr(0, 5) == "thumb") {
71 if (Len >= 7 && TT[5] == 'v')
75 unsigned SubVer = TT[Idx];
76 if (SubVer >= '7' && SubVer <= '9') {
78 } else if (SubVer == '6') {
80 if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
81 ARMArchVersion = V6T2;
82 } else if (SubVer == '5') {
84 if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
85 ARMArchVersion = V5TE;
86 } else if (SubVer == '4') {
87 if (Len >= Idx+2 && TT[Idx+1] == 't')
94 // Thumb2 implies at least V6T2.
95 if (ARMArchVersion >= V6T2)
97 else if (ThumbMode >= Thumb2)
98 ARMArchVersion = V6T2;
101 if (TT.find("-darwin") != std::string::npos)
103 TargetType = isDarwin;
106 if (TT.find("eabi") != std::string::npos)
107 TargetABI = ARM_ABI_AAPCS;
112 if (isTargetDarwin())
113 IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);
115 if (!isThumb() || hasThumb2())
116 PostRAScheduler = true;
118 // Set CPU specific features.
119 if (CPUString == "cortex-a8") {
120 // On Cortex-a8, it's faster to perform some single-precision FP
121 // operations with NEON instructions.
122 if (UseNEONFP.getPosition() == 0)
123 UseNEONForSinglePrecisionFP = true;
127 /// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.
129 ARMSubtarget::GVIsIndirectSymbol(GlobalValue *GV, Reloc::Model RelocM) const {
130 if (RelocM == Reloc::Static)
133 // Materializable GVs (in JIT lazy compilation mode) do not require an extra
135 bool isDecl = GV->isDeclaration() && !GV->isMaterializable();
137 if (!isTargetDarwin()) {
138 // Extra load is needed for all externally visible.
139 if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
143 if (RelocM == Reloc::PIC_) {
144 // If this is a strong reference to a definition, it is definitely not
146 if (!isDecl && !GV->isWeakForLinker())
149 // Unless we have a symbol with hidden visibility, we have to go through a
150 // normal $non_lazy_ptr stub because this symbol might be resolved late.
151 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
154 // If symbol visibility is hidden, we have a stub for common symbol
155 // references and external declarations.
156 if (isDecl || GV->hasCommonLinkage())
157 // Hidden $non_lazy_ptr reference.
162 // If this is a strong reference to a definition, it is definitely not
164 if (!isDecl && !GV->isWeakForLinker())
167 // Unless we have a symbol with hidden visibility, we have to go through a
168 // normal $non_lazy_ptr stub because this symbol might be resolved late.
169 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
177 bool ARMSubtarget::enablePostRAScheduler(
178 CodeGenOpt::Level OptLevel,
179 TargetSubtarget::AntiDepBreakMode& Mode,
180 RegClassVector& CriticalPathRCs) const {
181 Mode = TargetSubtarget::ANTIDEP_CRITICAL;
182 CriticalPathRCs.clear();
183 CriticalPathRCs.push_back(&ARM::GPRRegClass);
184 return PostRAScheduler && OptLevel >= CodeGenOpt::Default;