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 LLVM_CODEGEN_ASMPRINTER_DWARFEXCEPTION_H
15 #define LLVM_CODEGEN_ASMPRINTER_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 /// UsesLSDA - Indicates whether an FDE that uses the CIE at the given index
55 /// uses an LSDA. If so, then we need to encode that information in the CIE's
57 DenseMap<unsigned, bool> UsesLSDA;
59 /// shouldEmitTable - Per-function flag to indicate if EH tables should
63 /// shouldEmitMoves - Per-function flag to indicate if frame moves info
64 /// should be emitted.
67 /// shouldEmitTableModule - Per-module flag to indicate if EH tables
68 /// should be emitted.
69 bool shouldEmitTableModule;
71 /// shouldEmitFrameModule - Per-module flag to indicate if frame moves
72 /// should be emitted.
73 bool shouldEmitMovesModule;
75 /// ExceptionTimer - Timer for the Dwarf exception writer.
76 Timer *ExceptionTimer;
78 unsigned SizeOfEncodedValue(unsigned Encoding);
80 /// EmitCIE - Emit a Common Information Entry (CIE). This holds information
81 /// that is shared among many Frame Description Entries. There is at least
82 /// one CIE in every non-empty .debug_frame section.
83 void EmitCIE(const Function *Personality, unsigned Index);
85 /// EmitFDE - Emit the Frame Description Entry (FDE) for the function.
86 void EmitFDE(const FunctionEHFrameInfo &EHFrameInfo);
88 /// EmitExceptionTable - Emit landing pads and actions.
90 /// The general organization of the table is complex, but the basic concepts
91 /// are easy. First there is a header which describes the location and
92 /// organization of the three components that follow.
93 /// 1. The landing pad site information describes the range of code covered
94 /// by the try. In our case it's an accumulation of the ranges covered
95 /// by the invokes in the try. There is also a reference to the landing
96 /// pad that handles the exception once processed. Finally an index into
97 /// the actions table.
98 /// 2. The action table, in our case, is composed of pairs of type ids
99 /// and next action offset. Starting with the action index from the
100 /// landing pad site, each type Id is checked for a match to the current
101 /// exception. If it matches then the exception and type id are passed
102 /// on to the landing pad. Otherwise the next action is looked up. This
103 /// chain is terminated with a next action of zero. If no type id is
104 /// found the the frame is unwound and handling continues.
105 /// 3. Type id table contains references to all the C++ typeinfo for all
106 /// catches in the function. This tables is reversed indexed base 1.
108 /// SharedTypeIds - How many leading type ids two landing pads have in common.
109 static unsigned SharedTypeIds(const LandingPadInfo *L,
110 const LandingPadInfo *R);
112 /// PadLT - Order landing pads lexicographically by type id.
113 static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R);
116 static inline unsigned getEmptyKey() { return -1U; }
117 static inline unsigned getTombstoneKey() { return -2U; }
118 static unsigned getHashValue(const unsigned &Key) { return Key; }
119 static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
120 static bool isPod() { return true; }
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 /// ActionEntry - Structure describing an entry in the actions table.
135 int ValueForTypeID; // The value to write - may not be equal to the type id.
137 struct ActionEntry *Previous;
140 /// CallSiteEntry - Structure describing an entry in the call-site table.
141 struct CallSiteEntry {
142 // The 'try-range' is BeginLabel .. EndLabel.
143 unsigned BeginLabel; // zero indicates the start of the function.
144 unsigned EndLabel; // zero indicates the end of the function.
146 // The landing pad starts at PadLabel.
147 unsigned PadLabel; // zero indicates that there is no landing pad.
151 /// ComputeActionsTable - Compute the actions table and gather the first
152 /// action index for each landing pad site.
153 unsigned ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*>&LPs,
154 SmallVectorImpl<ActionEntry> &Actions,
155 SmallVectorImpl<unsigned> &FirstActions);
157 /// ComputeCallSiteTable - Compute the call-site table. The entry for an
158 /// invoke has a try-range containing the call, a non-zero landing pad and an
159 /// appropriate action. The entry for an ordinary call has a try-range
160 /// containing the call and zero for the landing pad and the action. Calls
161 /// marked 'nounwind' have no entry and must not be contained in the try-range
162 /// of any entry - they form gaps in the table. Entries must be ordered by
163 /// try-range address.
164 void ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
165 const RangeMapType &PadMap,
166 const SmallVectorImpl<const LandingPadInfo *> &LPs,
167 const SmallVectorImpl<unsigned> &FirstActions);
168 void EmitExceptionTable();
171 //===--------------------------------------------------------------------===//
172 // Main entry points.
174 DwarfException(raw_ostream &OS, AsmPrinter *A, const MCAsmInfo *T);
175 virtual ~DwarfException();
177 /// BeginModule - Emit all exception information that should come prior to the
179 void BeginModule(Module *m, MachineModuleInfo *mmi) {
184 /// EndModule - Emit all exception information that should come after the
188 /// BeginFunction - Gather pre-function exception information. Assumes being
189 /// emitted immediately after the function entry point.
190 void BeginFunction(MachineFunction *MF);
192 /// EndFunction - Gather and emit post-function exception information.
196 } // End of namespace llvm