1 //===- MCLinkerOptimizationHint.h - LOH interface ---------------*- C++ -*-===//
4 // The LLVM Compiler Infrastructure
6 // This file is distributed under the University of Illinois Open Source
7 // License. See LICENSE.TXT for details.
9 //===----------------------------------------------------------------------===//
11 // This file declares some helpers classes to handle Linker Optimization Hint
14 // FIXME: LOH interface supports only MachO format at the moment.
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
18 #define LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
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"
28 // Forward declarations.
32 /// Linker Optimization Hint Type.
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.
44 static inline StringRef MCLOHDirectiveName() {
45 return StringRef(".loh");
48 static inline bool isValidMCLOHType(MCLOHType Kind) {
49 return Kind >= MCLOH_AdrpAdrp && Kind <= MCLOH_AdrpLdrGot;
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)
66 static inline StringRef MCLOHIdToName(MCLOHType Kind) {
67 #define MCLOHCaseIdToName(Name) case MCLOH_ ## Name: return StringRef(#Name);
69 MCLOHCaseIdToName(AdrpAdrp);
70 MCLOHCaseIdToName(AdrpLdr);
71 MCLOHCaseIdToName(AdrpAddLdr);
72 MCLOHCaseIdToName(AdrpLdrGotLdr);
73 MCLOHCaseIdToName(AdrpAddStr);
74 MCLOHCaseIdToName(AdrpLdrGotStr);
75 MCLOHCaseIdToName(AdrpAdd);
76 MCLOHCaseIdToName(AdrpLdrGot);
81 static inline int MCLOHIdToNbArgs(MCLOHType Kind) {
83 // LOH with two arguments
87 case MCLOH_AdrpLdrGot:
89 // LOH with three arguments
90 case MCLOH_AdrpAddLdr:
91 case MCLOH_AdrpLdrGotLdr:
92 case MCLOH_AdrpAddStr:
93 case MCLOH_AdrpLdrGotStr:
100 class raw_counting_ostream : public raw_ostream {
103 void write_impl(const char *, size_t size) override { Count += size; }
105 uint64_t current_pos() const override { return Count; }
108 ~raw_counting_ostream() { flush(); }
112 /// Store Linker Optimization Hint information (LOH).
113 class MCLOHDirective {
116 /// Arguments of this directive. Order matters.
117 SmallVector<MCSymbol *, 3> Args;
119 /// Emit this directive in @p OutStream using the information available
120 /// in the given @p ObjWriter and @p Layout to get the address of the
121 /// arguments within the object file.
122 void Emit_impl(raw_ostream &OutStream, const MachObjectWriter &ObjWriter,
123 const MCAsmLayout &Layout) const;
126 typedef SmallVectorImpl<MCSymbol *> LOHArgs;
128 MCLOHDirective(MCLOHType Kind, const LOHArgs &Args)
129 : Kind(Kind), Args(Args.begin(), Args.end()) {
130 assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!");
133 MCLOHType getKind() const { return Kind; }
135 const LOHArgs &getArgs() const { return Args; }
137 /// Emit this directive as:
138 /// <kind, numArgs, addr1, ..., addrN>
139 void Emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const {
140 raw_ostream &OutStream = ObjWriter.getStream();
141 Emit_impl(OutStream, ObjWriter, Layout);
144 /// Get the size in bytes of this directive if emitted in @p ObjWriter with
145 /// the given @p Layout.
146 uint64_t getEmitSize(const MachObjectWriter &ObjWriter,
147 const MCAsmLayout &Layout) const {
148 raw_counting_ostream OutStream;
149 Emit_impl(OutStream, ObjWriter, Layout);
150 return OutStream.tell();
154 class MCLOHContainer {
155 /// Keep track of the emit size of all the LOHs.
156 mutable uint64_t EmitSize;
158 /// Keep track of all LOH directives.
159 SmallVector<MCLOHDirective, 32> Directives;
162 typedef SmallVectorImpl<MCLOHDirective> LOHDirectives;
164 MCLOHContainer() : EmitSize(0) {};
166 /// Const accessor to the directives.
167 const LOHDirectives &getDirectives() const {
171 /// Add the directive of the given kind @p Kind with the given arguments
172 /// @p Args to the container.
173 void addDirective(MCLOHType Kind, const MCLOHDirective::LOHArgs &Args) {
174 Directives.push_back(MCLOHDirective(Kind, Args));
177 /// Get the size of the directives if emitted.
178 uint64_t getEmitSize(const MachObjectWriter &ObjWriter,
179 const MCAsmLayout &Layout) const {
181 for (const MCLOHDirective &D : Directives)
182 EmitSize += D.getEmitSize(ObjWriter, Layout);
187 /// Emit all Linker Optimization Hint in one big table.
188 /// Each line of the table is emitted by LOHDirective::Emit.
189 void Emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const {
190 for (const MCLOHDirective &D : Directives)
191 D.Emit(ObjWriter, Layout);
200 // Add types for specialized template using MCSymbol.
201 typedef MCLOHDirective::LOHArgs MCLOHArgs;
202 typedef MCLOHContainer::LOHDirectives MCLOHDirectives;
204 } // end namespace llvm