DwarfException.h revision 2386fc8daa682c7b6c2479cd9c9c3113581c41db 
1//===-- DwarfException.h - Dwarf Exception Framework -----------*- C++ -*--===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains support for writing dwarf exception info into asm files.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CODEGEN_ASMPRINTER_DWARFEXCEPTION_H
15#define LLVM_CODEGEN_ASMPRINTER_DWARFEXCEPTION_H
16
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/CodeGen/AsmPrinter.h"
19#include <vector>
20
21namespace llvm {
22
23template <typename T> class SmallVectorImpl;
24struct LandingPadInfo;
25class MachineModuleInfo;
26class MachineMove;
27class MachineInstr;
28class MachineFunction;
29class MCAsmInfo;
30class MCExpr;
31class MCSymbol;
32class Function;
33class AsmPrinter;
34
35//===----------------------------------------------------------------------===//
36/// DwarfException - Emits Dwarf exception handling directives.
37///
38class DwarfException {
39protected:
40  /// Asm - Target of Dwarf emission.
41  AsmPrinter *Asm;
42
43  /// MMI - Collected machine module information.
44  MachineModuleInfo *MMI;
45
46  /// SharedTypeIds - How many leading type ids two landing pads have in common.
47  static unsigned SharedTypeIds(const LandingPadInfo *L,
48                                const LandingPadInfo *R);
49
50  /// PadLT - Order landing pads lexicographically by type id.
51  static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R);
52
53  /// PadRange - Structure holding a try-range and the associated landing pad.
54  struct PadRange {
55    // The index of the landing pad.
56    unsigned PadIndex;
57    // The index of the begin and end labels in the landing pad's label lists.
58    unsigned RangeIndex;
59  };
60
61  typedef DenseMap<MCSymbol *, PadRange> RangeMapType;
62
63  /// ActionEntry - Structure describing an entry in the actions table.
64  struct ActionEntry {
65    int ValueForTypeID; // The value to write - may not be equal to the type id.
66    int NextAction;
67    unsigned Previous;
68  };
69
70  /// CallSiteEntry - Structure describing an entry in the call-site table.
71  struct CallSiteEntry {
72    // The 'try-range' is BeginLabel .. EndLabel.
73    MCSymbol *BeginLabel; // zero indicates the start of the function.
74    MCSymbol *EndLabel;   // zero indicates the end of the function.
75
76    // The landing pad starts at PadLabel.
77    MCSymbol *PadLabel;   // zero indicates that there is no landing pad.
78    unsigned Action;
79  };
80
81  /// ComputeActionsTable - Compute the actions table and gather the first
82  /// action index for each landing pad site.
83  unsigned ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*>&LPs,
84                               SmallVectorImpl<ActionEntry> &Actions,
85                               SmallVectorImpl<unsigned> &FirstActions);
86
87  /// CallToNoUnwindFunction - Return `true' if this is a call to a function
88  /// marked `nounwind'. Return `false' otherwise.
89  bool CallToNoUnwindFunction(const MachineInstr *MI);
90
91  /// ComputeCallSiteTable - Compute the call-site table.  The entry for an
92  /// invoke has a try-range containing the call, a non-zero landing pad and an
93  /// appropriate action.  The entry for an ordinary call has a try-range
94  /// containing the call and zero for the landing pad and the action.  Calls
95  /// marked 'nounwind' have no entry and must not be contained in the try-range
96  /// of any entry - they form gaps in the table.  Entries must be ordered by
97  /// try-range address.
98  void ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
99                            const RangeMapType &PadMap,
100                            const SmallVectorImpl<const LandingPadInfo *> &LPs,
101                            const SmallVectorImpl<unsigned> &FirstActions);
102
103  /// EmitExceptionTable - Emit landing pads and actions.
104  ///
105  /// The general organization of the table is complex, but the basic concepts
106  /// are easy.  First there is a header which describes the location and
107  /// organization of the three components that follow.
108  ///  1. The landing pad site information describes the range of code covered
109  ///     by the try.  In our case it's an accumulation of the ranges covered
110  ///     by the invokes in the try.  There is also a reference to the landing
111  ///     pad that handles the exception once processed.  Finally an index into
112  ///     the actions table.
113  ///  2. The action table, in our case, is composed of pairs of type ids
114  ///     and next action offset.  Starting with the action index from the
115  ///     landing pad site, each type Id is checked for a match to the current
116  ///     exception.  If it matches then the exception and type id are passed
117  ///     on to the landing pad.  Otherwise the next action is looked up.  This
118  ///     chain is terminated with a next action of zero.  If no type id is
119  ///     found the frame is unwound and handling continues.
120  ///  3. Type id table contains references to all the C++ typeinfo for all
121  ///     catches in the function.  This tables is reversed indexed base 1.
122  void EmitExceptionTable();
123
124  virtual void EmitTypeInfos(unsigned TTypeEncoding);
125
126public:
127  //===--------------------------------------------------------------------===//
128  // Main entry points.
129  //
130  DwarfException(AsmPrinter *A);
131  virtual ~DwarfException();
132
133  /// EndModule - Emit all exception information that should come after the
134  /// content.
135  virtual void EndModule();
136
137  /// BeginFunction - Gather pre-function exception information.  Assumes being
138  /// emitted immediately after the function entry point.
139  virtual void BeginFunction(const MachineFunction *MF);
140
141  /// EndFunction - Gather and emit post-function exception information.
142  virtual void EndFunction();
143};
144
145class DwarfCFIException : public DwarfException {
146  /// shouldEmitPersonality - Per-function flag to indicate if .cfi_personality
147  /// should be emitted.
148  bool shouldEmitPersonality;
149
150  /// shouldEmitLSDA - Per-function flag to indicate if .cfi_lsda
151  /// should be emitted.
152  bool shouldEmitLSDA;
153
154  /// shouldEmitMoves - Per-function flag to indicate if frame moves info
155  /// should be emitted.
156  bool shouldEmitMoves;
157
158  AsmPrinter::CFIMoveType moveTypeModule;
159
160public:
161  //===--------------------------------------------------------------------===//
162  // Main entry points.
163  //
164  DwarfCFIException(AsmPrinter *A);
165  virtual ~DwarfCFIException();
166
167  /// EndModule - Emit all exception information that should come after the
168  /// content.
169  virtual void EndModule();
170
171  /// BeginFunction - Gather pre-function exception information.  Assumes being
172  /// emitted immediately after the function entry point.
173  virtual void BeginFunction(const MachineFunction *MF);
174
175  /// EndFunction - Gather and emit post-function exception information.
176  virtual void EndFunction();
177};
178
179class ARMException : public DwarfException {
180  void EmitTypeInfos(unsigned TTypeEncoding);
181public:
182  //===--------------------------------------------------------------------===//
183  // Main entry points.
184  //
185  ARMException(AsmPrinter *A);
186  virtual ~ARMException();
187
188  /// EndModule - Emit all exception information that should come after the
189  /// content.
190  virtual void EndModule();
191
192  /// BeginFunction - Gather pre-function exception information.  Assumes being
193  /// emitted immediately after the function entry point.
194  virtual void BeginFunction(const MachineFunction *MF);
195
196  /// EndFunction - Gather and emit post-function exception information.
197  virtual void EndFunction();
198};
199
200class Win64Exception : public DwarfException {
201  /// shouldEmitPersonality - Per-function flag to indicate if personality
202  /// info should be emitted.
203  bool shouldEmitPersonality;
204
205  /// shouldEmitLSDA - Per-function flag to indicate if the LSDA
206  /// should be emitted.
207  bool shouldEmitLSDA;
208
209  /// shouldEmitMoves - Per-function flag to indicate if frame moves info
210  /// should be emitted.
211  bool shouldEmitMoves;
212
213public:
214  //===--------------------------------------------------------------------===//
215  // Main entry points.
216  //
217  Win64Exception(AsmPrinter *A);
218  virtual ~Win64Exception();
219
220  /// EndModule - Emit all exception information that should come after the
221  /// content.
222  virtual void EndModule();
223
224  /// BeginFunction - Gather pre-function exception information.  Assumes being
225  /// emitted immediately after the function entry point.
226  virtual void BeginFunction(const MachineFunction *MF);
227
228  /// EndFunction - Gather and emit post-function exception information.
229  virtual void EndFunction();
230};
231
232} // End of namespace llvm
233
234#endif
235