1 //===-- DwarfException.h - Dwarf Exception Framework -----------*- C++ -*--===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing dwarf exception info into asm files.
12 //===----------------------------------------------------------------------===//
14 #ifndef DWARFEXCEPTION_H__
15 #define DWARFEXCEPTION_H__
18 #include "DwarfPrinter.h"
19 #include "llvm/CodeGen/AsmPrinter.h"
20 #include "llvm/ADT/DenseMap.h"
25 struct LandingPadInfo;
26 class MachineModuleInfo;
31 //===----------------------------------------------------------------------===//
32 /// DwarfException - Emits Dwarf exception handling directives.
34 class VISIBILITY_HIDDEN DwarfException : public Dwarf {
35 struct FunctionEHFrameInfo {
38 unsigned PersonalityIndex;
41 std::vector<MachineMove> Moves;
42 const Function * function;
44 FunctionEHFrameInfo(const std::string &FN, unsigned Num, unsigned P,
46 const std::vector<MachineMove> &M,
48 FnName(FN), Number(Num), PersonalityIndex(P),
49 hasCalls(hC), hasLandingPads(hL), Moves(M), function (f) { }
52 std::vector<FunctionEHFrameInfo> EHFrames;
54 /// shouldEmitTable - Per-function flag to indicate if EH tables should
58 /// shouldEmitMoves - Per-function flag to indicate if frame moves info
59 /// should be emitted.
62 /// shouldEmitTableModule - Per-module flag to indicate if EH tables
63 /// should be emitted.
64 bool shouldEmitTableModule;
66 /// shouldEmitFrameModule - Per-module flag to indicate if frame moves
67 /// should be emitted.
68 bool shouldEmitMovesModule;
70 /// ExceptionTimer - Timer for the Dwarf exception writer.
71 Timer *ExceptionTimer;
73 /// EmitCommonEHFrame - Emit the common eh unwind frame.
75 void EmitCommonEHFrame(const Function *Personality, unsigned Index);
77 /// EmitEHFrame - Emit function exception frame information.
79 void EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo);
81 /// EmitExceptionTable - Emit landing pads and actions.
83 /// The general organization of the table is complex, but the basic concepts
84 /// are easy. First there is a header which describes the location and
85 /// organization of the three components that follow.
86 /// 1. The landing pad site information describes the range of code covered
87 /// by the try. In our case it's an accumulation of the ranges covered
88 /// by the invokes in the try. There is also a reference to the landing
89 /// pad that handles the exception once processed. Finally an index into
90 /// the actions table.
91 /// 2. The action table, in our case, is composed of pairs of type ids
92 /// and next action offset. Starting with the action index from the
93 /// landing pad site, each type Id is checked for a match to the current
94 /// exception. If it matches then the exception and type id are passed
95 /// on to the landing pad. Otherwise the next action is looked up. This
96 /// chain is terminated with a next action of zero. If no type id is
97 /// found the the frame is unwound and handling continues.
98 /// 3. Type id table contains references to all the C++ typeinfo for all
99 /// catches in the function. This tables is reversed indexed base 1.
101 /// SharedTypeIds - How many leading type ids two landing pads have in common.
102 static unsigned SharedTypeIds(const LandingPadInfo *L,
103 const LandingPadInfo *R);
105 /// PadLT - Order landing pads lexicographically by type id.
106 static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R);
109 static inline unsigned getEmptyKey() { return -1U; }
110 static inline unsigned getTombstoneKey() { return -2U; }
111 static unsigned getHashValue(const unsigned &Key) { return Key; }
112 static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
113 static bool isPod() { return true; }
116 /// ActionEntry - Structure describing an entry in the actions table.
118 int ValueForTypeID; // The value to write - may not be equal to the type id.
120 struct ActionEntry *Previous;
123 /// PadRange - Structure holding a try-range and the associated landing pad.
125 // The index of the landing pad.
127 // The index of the begin and end labels in the landing pad's label lists.
131 typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
133 /// CallSiteEntry - Structure describing an entry in the call-site table.
134 struct CallSiteEntry {
135 // The 'try-range' is BeginLabel .. EndLabel.
136 unsigned BeginLabel; // zero indicates the start of the function.
137 unsigned EndLabel; // zero indicates the end of the function.
138 // The landing pad starts at PadLabel.
139 unsigned PadLabel; // zero indicates that there is no landing pad.
143 void EmitExceptionTable();
146 //===--------------------------------------------------------------------===//
147 // Main entry points.
149 DwarfException(raw_ostream &OS, AsmPrinter *A, const TargetAsmInfo *T);
150 virtual ~DwarfException();
152 /// SetModuleInfo - Set machine module information when it's known that pass
153 /// manager has created it. Set by the target AsmPrinter.
154 void SetModuleInfo(MachineModuleInfo *mmi) {
158 /// BeginModule - Emit all exception information that should come prior to the
160 void BeginModule(Module *M) {
164 /// EndModule - Emit all exception information that should come after the
168 /// BeginFunction - Gather pre-function exception information. Assumes being
169 /// emitted immediately after the function entry point.
170 void BeginFunction(MachineFunction *MF);
172 /// EndFunction - Gather and emit post-function exception information.
176 } // End of namespace llvm