LLVM  3.7.0
MCLinkerOptimizationHint.h
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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"
25 
26 namespace llvm {
27 
28 // Forward declarations.
29 class MCAsmLayout;
30 class MCSymbol;
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 
44 static inline StringRef MCLOHDirectiveName() {
45  return StringRef(".loh");
46 }
47 
48 static inline bool isValidMCLOHType(unsigned Kind) {
49  return Kind >= MCLOH_AdrpAdrp && Kind <= MCLOH_AdrpLdrGot;
50 }
51 
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 
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 
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:
92  case MCLOH_AdrpAddStr:
94  return 3;
95  }
96  return -1;
97 }
98 
99 /// Store Linker Optimization Hint information (LOH).
101  MCLOHType Kind;
102 
103  /// Arguments of this directive. Order matters.
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:
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  class raw_counting_ostream : public raw_ostream {
136  uint64_t Count;
137 
138  void write_impl(const char *, size_t size) override { Count += size; }
139 
140  uint64_t current_pos() const override { return Count; }
141 
142  public:
143  raw_counting_ostream() : Count(0) {}
144  ~raw_counting_ostream() override { flush(); }
145  };
146 
147  raw_counting_ostream OutStream;
148  emit_impl(OutStream, ObjWriter, Layout);
149  return OutStream.tell();
150  }
151 };
152 
154  /// Keep track of the emit size of all the LOHs.
155  mutable uint64_t EmitSize;
156 
157  /// Keep track of all LOH directives.
159 
160 public:
162 
163  MCLOHContainer() : EmitSize(0) {};
164 
165  /// Const accessor to the directives.
166  const LOHDirectives &getDirectives() const {
167  return Directives;
168  }
169 
170  /// Add the directive of the given kind \p Kind with the given arguments
171  /// \p Args to the container.
173  Directives.push_back(MCLOHDirective(Kind, Args));
174  }
175 
176  /// Get the size of the directives if emitted.
177  uint64_t getEmitSize(const MachObjectWriter &ObjWriter,
178  const MCAsmLayout &Layout) const {
179  if (!EmitSize) {
180  for (const MCLOHDirective &D : Directives)
181  EmitSize += D.getEmitSize(ObjWriter, Layout);
182  }
183  return EmitSize;
184  }
185 
186  /// Emit all Linker Optimization Hint in one big table.
187  /// Each line of the table is emitted by LOHDirective::emit.
188  void emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const {
189  for (const MCLOHDirective &D : Directives)
190  D.emit(ObjWriter, Layout);
191  }
192 
193  void reset() {
194  Directives.clear();
195  EmitSize = 0;
196  }
197 };
198 
199 // Add types for specialized template using MCSymbol.
202 
203 } // end namespace llvm
204 
205 #endif
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:240
uint64_t getEmitSize(const MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const
Get the size in bytes of this directive if emitted in ObjWriter with the given Layout.
raw_ostream & getStream()
MCLOHContainer::LOHDirectives MCLOHDirectives
uint64_t getEmitSize(const MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const
Get the size of the directives if emitted.
void emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const
Emit this directive as: <kind, numArgs, addr1, ..., addrN>
Adrp _v -> Add _v -> Ldr.
const_iterator begin(StringRef path)
Get begin iterator over path.
Definition: Path.cpp:232
void emit(MachObjectWriter &ObjWriter, const MCAsmLayout &Layout) const
Emit all Linker Optimization Hint in one big table.
Adrp _v -> Ldr _v -> Ldr.
Store Linker Optimization Hint information (LOH).
Encapsulates the layout of an assembly file at a particular point in time.
Definition: MCAsmLayout.h:29
MCLOHDirective(MCLOHType Kind, const LOHArgs &Args)
#define MCLOHCaseIdToName(Name)
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APInt.h:33
MCLOHDirective::LOHArgs MCLOHArgs
const LOHArgs & getArgs() const
#define MCLOHCaseNameToId(Name)
A switch()-like statement whose cases are string literals.
Definition: StringSwitch.h:42
static int MCLOHNameToId(StringRef Name)
MCLOHType
Linker Optimization Hint Type.
const LOHDirectives & getDirectives() const
Const accessor to the directives.
SmallVectorImpl< MCSymbol * > LOHArgs
Adrp _v -> Add _v -> Str.
void addDirective(MCLOHType Kind, const MCLOHDirective::LOHArgs &Args)
Add the directive of the given kind Kind with the given arguments Args to the container.
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:861
static StringRef MCLOHDirectiveName()
Adrp xY, _v1 -> Adrp xY, _v2.
static bool isValidMCLOHType(unsigned Kind)
Adrp _v -> Ldr _v -> Str.
SmallVectorImpl< MCLOHDirective > LOHDirectives
void size_t size
const ARM::ArchExtKind Kind
static int MCLOHIdToNbArgs(MCLOHType Kind)
static StringRef MCLOHIdToName(MCLOHType Kind)
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:38
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:40