1 //===- MCLinkerOptimizationHint.h - LOH interface ---------------*- C++ -*-===//
2 //
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/StringRef.h"
22 #include "llvm/ADT/StringSwitch.h"
23 #include "llvm/Support/raw_ostream.h"
24
25 namespace llvm {
26
27 // Forward declarations.
28 class MCAsmLayout;
29 class MCSymbol;
30 class MachObjectWriter;
31
32 /// Linker Optimization Hint Type.
33 enum 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
MCLOHDirectiveName()44 static inline StringRef MCLOHDirectiveName() {
45 return StringRef(".loh");
46 }
47
isValidMCLOHType(unsigned Kind)48 static inline bool isValidMCLOHType(unsigned Kind) {
49 return Kind >= MCLOH_AdrpAdrp && Kind <= MCLOH_AdrpLdrGot;
50 }
51
MCLOHNameToId(StringRef Name)52 static 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
MCLOHIdToName(MCLOHType Kind)66 static 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
MCLOHIdToNbArgs(MCLOHType Kind)81 static 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).
100 class 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
112 public:
113 typedef SmallVectorImpl<MCSymbol *> LOHArgs;
114
MCLOHDirective(MCLOHType Kind,const LOHArgs & Args)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
getKind()120 MCLOHType getKind() const { return Kind; }
121
getArgs()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
128 /// Get the size in bytes of this directive if emitted in \p ObjWriter with
129 /// the given \p Layout.
130 uint64_t getEmitSize(const MachObjectWriter &ObjWriter,
131 const MCAsmLayout &Layout) const;
132 };
133
134 class MCLOHContainer {
135 /// Keep track of the emit size of all the LOHs.
136 mutable uint64_t EmitSize;
137
138 /// Keep track of all LOH directives.
139 SmallVector<MCLOHDirective, 32> Directives;
140
141 public:
142 typedef SmallVectorImpl<MCLOHDirective> LOHDirectives;
143
MCLOHContainer()144 MCLOHContainer() : EmitSize(0) {}
145
146 /// Const accessor to the directives.
getDirectives()147 const LOHDirectives &getDirectives() const {
148 return Directives;
149 }
150
151 /// Add the directive of the given kind \p Kind with the given arguments
152 /// \p Args to the container.
addDirective(MCLOHType Kind,const MCLOHDirective::LOHArgs & Args)153 void addDirective(MCLOHType Kind, const MCLOHDirective::LOHArgs &Args) {
154 Directives.push_back(MCLOHDirective(Kind, Args));
155 }
156
157 /// Get the size of the directives if emitted.
getEmitSize(const MachObjectWriter & ObjWriter,const MCAsmLayout & Layout)158 uint64_t getEmitSize(const MachObjectWriter &ObjWriter,
159 const MCAsmLayout &Layout) const {
160 if (!EmitSize) {
161 for (const MCLOHDirective &D : Directives)
162 EmitSize += D.getEmitSize(ObjWriter, Layout);
163 }
164 return EmitSize;
165 }
166
167 /// Emit all Linker Optimization Hint in one big table.
168 /// Each line of the table is emitted by LOHDirective::emit.
emit(MachObjectWriter & ObjWriter,const MCAsmLayout & Layout)169 void emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const {
170 for (const MCLOHDirective &D : Directives)
171 D.emit(ObjWriter, Layout);
172 }
173
reset()174 void reset() {
175 Directives.clear();
176 EmitSize = 0;
177 }
178 };
179
180 // Add types for specialized template using MCSymbol.
181 typedef MCLOHDirective::LOHArgs MCLOHArgs;
182 typedef MCLOHContainer::LOHDirectives MCLOHDirectives;
183
184 } // end namespace llvm
185
186 #endif
187