MCLinkerOptimizationHint.h revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338
145afe016bed87b9c6946184709058b39ede3f77ajwong@chromium.org//===- MCLinkerOptimizationHint.h - LOH interface ---------------*- C++ -*-===// 245afe016bed87b9c6946184709058b39ede3f77ajwong@chromium.org// 3// 4// The LLVM Compiler Infrastructure 5// 6// This file is distributed under the University of Illinois Open Source 7// License. See LICENSE.TXT for details. 8// 9//===----------------------------------------------------------------------===// 10// 11// This file declares some helpers classes to handle Linker Optimization Hint 12// (LOH). 13// 14// FIXME: LOH interface supports only MachO format at the moment. 15//===----------------------------------------------------------------------===// 16 17#ifndef LLVM_MC_MCLINKEROPTIMIZATIONHINT_H 18#define LLVM_MC_MCLINKEROPTIMIZATIONHINT_H 19 20#include "llvm/ADT/SmallVector.h" 21#include "llvm/ADT/StringSwitch.h" 22#include "llvm/ADT/StringRef.h" 23#include "llvm/MC/MCMachObjectWriter.h" 24#include "llvm/Support/raw_ostream.h" 25 26namespace llvm { 27 28// Forward declarations. 29class MCAsmLayout; 30class MCSymbol; 31 32/// Linker Optimization Hint Type. 33enum MCLOHType { 34 MCLOH_AdrpAdrp = 0x1u, ///< Adrp xY, _v1@PAGE -> Adrp xY, _v2@PAGE. 35 MCLOH_AdrpLdr = 0x2u, ///< Adrp _v@PAGE -> Ldr _v@PAGEOFF. 36 MCLOH_AdrpAddLdr = 0x3u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF -> Ldr. 37 MCLOH_AdrpLdrGotLdr = 0x4u, ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF -> Ldr. 38 MCLOH_AdrpAddStr = 0x5u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF -> Str. 39 MCLOH_AdrpLdrGotStr = 0x6u, ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF -> Str. 40 MCLOH_AdrpAdd = 0x7u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF. 41 MCLOH_AdrpLdrGot = 0x8u ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF. 42}; 43 44static inline StringRef MCLOHDirectiveName() { 45 return StringRef(".loh"); 46} 47 48static inline bool isValidMCLOHType(MCLOHType Kind) { 49 return Kind >= MCLOH_AdrpAdrp && Kind <= MCLOH_AdrpLdrGot; 50} 51 52static inline int MCLOHNameToId(StringRef Name) { 53#define MCLOHCaseNameToId(Name) .Case(#Name, MCLOH_ ## Name) 54 return StringSwitch<int>(Name) 55 MCLOHCaseNameToId(AdrpAdrp) 56 MCLOHCaseNameToId(AdrpLdr) 57 MCLOHCaseNameToId(AdrpAddLdr) 58 MCLOHCaseNameToId(AdrpLdrGotLdr) 59 MCLOHCaseNameToId(AdrpAddStr) 60 MCLOHCaseNameToId(AdrpLdrGotStr) 61 MCLOHCaseNameToId(AdrpAdd) 62 MCLOHCaseNameToId(AdrpLdrGot) 63 .Default(-1); 64} 65 66static inline StringRef MCLOHIdToName(MCLOHType Kind) { 67#define MCLOHCaseIdToName(Name) case MCLOH_ ## Name: return StringRef(#Name); 68 switch (Kind) { 69 MCLOHCaseIdToName(AdrpAdrp); 70 MCLOHCaseIdToName(AdrpLdr); 71 MCLOHCaseIdToName(AdrpAddLdr); 72 MCLOHCaseIdToName(AdrpLdrGotLdr); 73 MCLOHCaseIdToName(AdrpAddStr); 74 MCLOHCaseIdToName(AdrpLdrGotStr); 75 MCLOHCaseIdToName(AdrpAdd); 76 MCLOHCaseIdToName(AdrpLdrGot); 77 } 78 return StringRef(); 79} 80 81static inline int MCLOHIdToNbArgs(MCLOHType Kind) { 82 switch (Kind) { 83 // LOH with two arguments 84 case MCLOH_AdrpAdrp: 85 case MCLOH_AdrpLdr: 86 case MCLOH_AdrpAdd: 87 case MCLOH_AdrpLdrGot: 88 return 2; 89 // LOH with three arguments 90 case MCLOH_AdrpAddLdr: 91 case MCLOH_AdrpLdrGotLdr: 92 case MCLOH_AdrpAddStr: 93 case MCLOH_AdrpLdrGotStr: 94 return 3; 95 } 96 return -1; 97} 98 99/// Store Linker Optimization Hint information (LOH). 100class MCLOHDirective { 101 MCLOHType Kind; 102 103 /// Arguments of this directive. Order matters. 104 SmallVector<MCSymbol *, 3> Args; 105 106 /// Emit this directive in @p OutStream using the information available 107 /// in the given @p ObjWriter and @p Layout to get the address of the 108 /// arguments within the object file. 109 void Emit_impl(raw_ostream &OutStream, const MachObjectWriter &ObjWriter, 110 const MCAsmLayout &Layout) const; 111 112public: 113 typedef SmallVectorImpl<MCSymbol *> LOHArgs; 114 115 MCLOHDirective(MCLOHType Kind, const LOHArgs &Args) 116 : Kind(Kind), Args(Args.begin(), Args.end()) { 117 assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!"); 118 } 119 120 MCLOHType getKind() const { return Kind; } 121 122 const LOHArgs &getArgs() const { return Args; } 123 124 /// Emit this directive as: 125 /// <kind, numArgs, addr1, ..., addrN> 126 void Emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const { 127 raw_ostream &OutStream = ObjWriter.getStream(); 128 Emit_impl(OutStream, ObjWriter, Layout); 129 } 130 131 /// Get the size in bytes of this directive if emitted in @p ObjWriter with 132 /// the given @p Layout. 133 uint64_t getEmitSize(const MachObjectWriter &ObjWriter, 134 const MCAsmLayout &Layout) const { 135 std::string Buffer; 136 raw_string_ostream OutStream(Buffer); 137 Emit_impl(OutStream, ObjWriter, Layout); 138 return OutStream.tell(); 139 } 140}; 141 142class MCLOHContainer { 143 /// Keep track of the emit size of all the LOHs. 144 mutable uint64_t EmitSize; 145 146 /// Keep track of all LOH directives. 147 SmallVector<MCLOHDirective, 32> Directives; 148 149public: 150 typedef SmallVectorImpl<MCLOHDirective> LOHDirectives; 151 152 MCLOHContainer() : EmitSize(0) {}; 153 154 /// Const accessor to the directives. 155 const LOHDirectives &getDirectives() const { 156 return Directives; 157 } 158 159 /// Add the directive of the given kind @p Kind with the given arguments 160 /// @p Args to the container. 161 void addDirective(MCLOHType Kind, const MCLOHDirective::LOHArgs &Args) { 162 Directives.push_back(MCLOHDirective(Kind, Args)); 163 } 164 165 /// Get the size of the directives if emitted. 166 uint64_t getEmitSize(const MachObjectWriter &ObjWriter, 167 const MCAsmLayout &Layout) const { 168 if (!EmitSize) { 169 for (const MCLOHDirective &D : Directives) 170 EmitSize += D.getEmitSize(ObjWriter, Layout); 171 } 172 return EmitSize; 173 } 174 175 /// Emit all Linker Optimization Hint in one big table. 176 /// Each line of the table is emitted by LOHDirective::Emit. 177 void Emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const { 178 for (const MCLOHDirective &D : Directives) 179 D.Emit(ObjWriter, Layout); 180 } 181 182 void reset() { 183 Directives.clear(); 184 EmitSize = 0; 185 } 186}; 187 188// Add types for specialized template using MCSymbol. 189typedef MCLOHDirective::LOHArgs MCLOHArgs; 190typedef MCLOHContainer::LOHDirectives MCLOHDirectives; 191 192} // end namespace llvm 193 194#endif 195