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"
22 ReserveR9("arm-reserve-r9", cl::Hidden,
23 cl::desc("Reserve R9, making it unavailable as GPR"));
25 UseNEONFP("arm-use-neon-fp",
26 cl::desc("Use NEON for single-precision FP"),
27 cl::init(false), cl::Hidden);
29 ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &FS,
33 , UseNEONForSinglePrecisionFP(UseNEONFP)
36 , PostRAScheduler(false)
37 , IsR9Reserved(ReserveR9)
39 , CPUString("generic")
40 , TargetType(isELF) // Default to ELF unless otherwise specified.
41 , TargetABI(ARM_ABI_APCS) {
42 // default to soft float ABI
43 if (FloatABIType == FloatABI::Default)
44 FloatABIType = FloatABI::Soft;
46 // Determine default and user specified characteristics
48 // Parse features string.
49 CPUString = ParseSubtargetFeatures(FS, CPUString);
51 // Set the boolean corresponding to the current target triple, or the default
52 // if one cannot be determined, to true.
53 unsigned Len = TT.length();
56 if (Len >= 5 && TT.substr(0, 4) == "armv")
58 else if (Len >= 6 && TT.substr(0, 5) == "thumb") {
60 if (Len >= 7 && TT[5] == 'v')
64 unsigned SubVer = TT[Idx];
65 if (SubVer > '4' && SubVer <= '9') {
68 } else if (SubVer == '6') {
70 if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
71 ARMArchVersion = V6T2;
72 } else if (SubVer == '5') {
74 if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
75 ARMArchVersion = V5TE;
77 if (ARMArchVersion >= V6T2)
82 // Thumb2 implies at least V6T2.
83 if (ARMArchVersion < V6T2 && ThumbMode >= Thumb2)
84 ARMArchVersion = V6T2;
87 if (TT.find("-darwin") != std::string::npos)
89 TargetType = isDarwin;
92 if (TT.find("eabi") != std::string::npos)
93 TargetABI = ARM_ABI_AAPCS;
99 IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);
101 if (!isThumb() || hasThumb2())
102 PostRAScheduler = true;
104 // Set CPU specific features.
105 if (CPUString == "cortex-a8") {
106 // On Cortex-a8, it's faster to perform some single-precision FP
107 // operations with NEON instructions.
108 if (UseNEONFP.getPosition() == 0)
109 UseNEONForSinglePrecisionFP = true;
113 /// GVIsIndirectSymbol - true if the GV will be accessed via an indirect symbol.
115 ARMSubtarget::GVIsIndirectSymbol(GlobalValue *GV, Reloc::Model RelocM) const {
116 if (RelocM == Reloc::Static)
119 // GV with ghost linkage (in JIT lazy compilation mode) do not require an
120 // extra load from stub.
121 bool isDecl = GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode();
123 if (!isTargetDarwin()) {
124 // Extra load is needed for all externally visible.
125 if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
129 if (RelocM == Reloc::PIC_) {
130 // If this is a strong reference to a definition, it is definitely not
132 if (!isDecl && !GV->isWeakForLinker())
135 // Unless we have a symbol with hidden visibility, we have to go through a
136 // normal $non_lazy_ptr stub because this symbol might be resolved late.
137 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.
140 // If symbol visibility is hidden, we have a stub for common symbol
141 // references and external declarations.
142 if (isDecl || GV->hasCommonLinkage())
143 // Hidden $non_lazy_ptr reference.
148 // If this is a strong reference to a definition, it is definitely not
150 if (!isDecl && !GV->isWeakForLinker())
153 // Unless we have a symbol with hidden visibility, we have to go through a
154 // normal $non_lazy_ptr stub because this symbol might be resolved late.
155 if (!GV->hasHiddenVisibility()) // Non-hidden $non_lazy_ptr reference.