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);
30 ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &FS,
34 , UseNEONForSinglePrecisionFP(UseNEONFP)
37 , PostRAScheduler(false)
38 , IsR9Reserved(ReserveR9)
40 , CPUString("generic")
41 , TargetType(isELF) // Default to ELF unless otherwise specified.
42 , TargetABI(ARM_ABI_APCS) {
43 // default to soft float ABI
44 if (FloatABIType == FloatABI::Default)
45 FloatABIType = FloatABI::Soft;
47 // Determine default and user specified characteristics
49 // Parse features string.
50 CPUString = ParseSubtargetFeatures(FS, CPUString);
52 // Set the boolean corresponding to the current target triple, or the default
53 // if one cannot be determined, to true.
54 unsigned Len = TT.length();
57 if (Len >= 5 && TT.substr(0, 4) == "armv")
59 else if (Len >= 6 && TT.substr(0, 5) == "thumb") {
61 if (Len >= 7 && TT[5] == 'v')
65 unsigned SubVer = TT[Idx];
66 if (SubVer > '4' && SubVer <= '9') {
69 } else if (SubVer == '6') {
71 if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
72 ARMArchVersion = V6T2;
73 } else if (SubVer == '5') {
75 if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
76 ARMArchVersion = V5TE;
78 if (ARMArchVersion >= V6T2)
83 // Thumb2 implies at least V6T2.
84 if (ARMArchVersion < V6T2 && ThumbMode >= Thumb2)
85 ARMArchVersion = V6T2;
88 if (TT.find("-darwin") != std::string::npos)
90 TargetType = isDarwin;
93 if (TT.find("eabi") != std::string::npos)
94 TargetABI = ARM_ABI_AAPCS;
100 IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);
102 if (!isThumb() || hasThumb2())
103 PostRAScheduler = true;
105 // Set CPU specific features.
106 if (CPUString == "cortex-a8") {
107 // On Cortex-a8, it's faster to perform some single-precision FP
108 // operations with NEON instructions.
109 if (UseNEONFP.getPosition() == 0)
110 UseNEONForSinglePrecisionFP = true;
114 /// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.
116 ARMSubtarget::GVIsIndirectSymbol(GlobalValue *GV, Reloc::Model RelocM) const {
117 if (RelocM == Reloc::Static)
120 // GV with ghost linkage (in JIT lazy compilation mode) do not require an
121 // extra load from stub.
122 bool isDecl = GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode();
124 if (!isTargetDarwin()) {
125 // Extra load is needed for all externally visible.
126 if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
130 if (RelocM == Reloc::PIC_) {
131 // If this is a strong reference to a definition, it is definitely not
133 if (!isDecl && !GV->isWeakForLinker())
136 // Unless we have a symbol with hidden visibility, we have to go through a
137 // normal $non_lazy_ptr stub because this symbol might be resolved late.
138 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
141 // If symbol visibility is hidden, we have a stub for common symbol
142 // references and external declarations.
143 if (isDecl || GV->hasCommonLinkage())
144 // Hidden $non_lazy_ptr reference.
149 // If this is a strong reference to a definition, it is definitely not
151 if (!isDecl && !GV->isWeakForLinker())
154 // Unless we have a symbol with hidden visibility, we have to go through a
155 // normal $non_lazy_ptr stub because this symbol might be resolved late.
156 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
164 bool ARMSubtarget::enablePostRAScheduler(
165 CodeGenOpt::Level OptLevel,
166 TargetSubtarget::AntiDepBreakMode& Mode,
167 RegClassVector& CriticalPathRCs) const {
168 Mode = TargetSubtarget::ANTIDEP_CRITICAL;
169 CriticalPathRCs.clear();
170 CriticalPathRCs.push_back(&ARM::GPRRegClass);
171 return PostRAScheduler && OptLevel >= CodeGenOpt::Default;