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
17 #include "llvm/ADT/DenseMap.h"
22 template <typename T> class SmallVectorImpl;
23 struct LandingPadInfo;
24 class MachineModuleInfo;
27 class MachineFunction;
34 //===----------------------------------------------------------------------===//
35 /// DwarfException - Emits Dwarf exception handling directives.
37 class DwarfException {
39 /// Asm - Target of Dwarf emission.
42 /// MMI - Collected machine module information.
43 MachineModuleInfo *MMI;
45 /// EmitExceptionTable - Emit landing pads and actions.
47 /// The general organization of the table is complex, but the basic concepts
48 /// are easy. First there is a header which describes the location and
49 /// organization of the three components that follow.
50 /// 1. The landing pad site information describes the range of code covered
51 /// by the try. In our case it's an accumulation of the ranges covered
52 /// by the invokes in the try. There is also a reference to the landing
53 /// pad that handles the exception once processed. Finally an index into
54 /// the actions table.
55 /// 2. The action table, in our case, is composed of pairs of type ids
56 /// and next action offset. Starting with the action index from the
57 /// landing pad site, each type Id is checked for a match to the current
58 /// exception. If it matches then the exception and type id are passed
59 /// on to the landing pad. Otherwise the next action is looked up. This
60 /// chain is terminated with a next action of zero. If no type id is
61 /// found the frame is unwound and handling continues.
62 /// 3. Type id table contains references to all the C++ typeinfo for all
63 /// catches in the function. This tables is reversed indexed base 1.
65 /// SharedTypeIds - How many leading type ids two landing pads have in common.
66 static unsigned SharedTypeIds(const LandingPadInfo *L,
67 const LandingPadInfo *R);
69 /// PadLT - Order landing pads lexicographically by type id.
70 static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R);
72 /// PadRange - Structure holding a try-range and the associated landing pad.
74 // The index of the landing pad.
76 // The index of the begin and end labels in the landing pad's label lists.
80 typedef DenseMap<MCSymbol *, PadRange> RangeMapType;
82 /// ActionEntry - Structure describing an entry in the actions table.
84 int ValueForTypeID; // The value to write - may not be equal to the type id.
89 /// CallSiteEntry - Structure describing an entry in the call-site table.
90 struct CallSiteEntry {
91 // The 'try-range' is BeginLabel .. EndLabel.
92 MCSymbol *BeginLabel; // zero indicates the start of the function.
93 MCSymbol *EndLabel; // zero indicates the end of the function.
95 // The landing pad starts at PadLabel.
96 MCSymbol *PadLabel; // zero indicates that there is no landing pad.
100 /// ComputeActionsTable - Compute the actions table and gather the first
101 /// action index for each landing pad site.
102 unsigned ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*>&LPs,
103 SmallVectorImpl<ActionEntry> &Actions,
104 SmallVectorImpl<unsigned> &FirstActions);
106 /// CallToNoUnwindFunction - Return `true' if this is a call to a function
107 /// marked `nounwind'. Return `false' otherwise.
108 bool CallToNoUnwindFunction(const MachineInstr *MI);
110 /// ComputeCallSiteTable - Compute the call-site table. The entry for an
111 /// invoke has a try-range containing the call, a non-zero landing pad and an
112 /// appropriate action. The entry for an ordinary call has a try-range
113 /// containing the call and zero for the landing pad and the action. Calls
114 /// marked 'nounwind' have no entry and must not be contained in the try-range
115 /// of any entry - they form gaps in the table. Entries must be ordered by
116 /// try-range address.
117 void ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites,
118 const RangeMapType &PadMap,
119 const SmallVectorImpl<const LandingPadInfo *> &LPs,
120 const SmallVectorImpl<unsigned> &FirstActions);
121 void EmitExceptionTable();
124 //===--------------------------------------------------------------------===//
125 // Main entry points.
127 DwarfException(AsmPrinter *A);
128 virtual ~DwarfException();
130 /// EndModule - Emit all exception information that should come after the
132 virtual void EndModule();
134 /// BeginFunction - Gather pre-function exception information. Assumes being
135 /// emitted immediately after the function entry point.
136 virtual void BeginFunction(const MachineFunction *MF);
138 /// EndFunction - Gather and emit post-function exception information.
139 virtual void EndFunction();
142 class DwarfCFIException : public DwarfException {
143 /// shouldEmitTable - Per-function flag to indicate if EH tables should
145 bool shouldEmitTable;
147 /// shouldEmitMoves - Per-function flag to indicate if frame moves info
148 /// should be emitted.
149 bool shouldEmitMoves;
151 /// shouldEmitTableModule - Per-module flag to indicate if EH tables
152 /// should be emitted.
153 bool shouldEmitTableModule;
155 //===--------------------------------------------------------------------===//
156 // Main entry points.
158 DwarfCFIException(AsmPrinter *A);
159 virtual ~DwarfCFIException();
161 /// EndModule - Emit all exception information that should come after the
163 virtual void EndModule();
165 /// BeginFunction - Gather pre-function exception information. Assumes being
166 /// emitted immediately after the function entry point.
167 virtual void BeginFunction(const MachineFunction *MF);
169 /// EndFunction - Gather and emit post-function exception information.
170 virtual void EndFunction();
173 class DwarfTableException : public DwarfException {
174 /// shouldEmitTable - Per-function flag to indicate if EH tables should
176 bool shouldEmitTable;
178 /// shouldEmitMoves - Per-function flag to indicate if frame moves info
179 /// should be emitted.
180 bool shouldEmitMoves;
182 /// shouldEmitTableModule - Per-module flag to indicate if EH tables
183 /// should be emitted.
184 bool shouldEmitTableModule;
186 /// shouldEmitMovesModule - Per-module flag to indicate if frame moves
187 /// should be emitted.
188 bool shouldEmitMovesModule;
190 struct FunctionEHFrameInfo {
191 MCSymbol *FunctionEHSym; // L_foo.eh
193 unsigned PersonalityIndex;
196 std::vector<MachineMove> Moves;
197 const Function *function;
199 FunctionEHFrameInfo(MCSymbol *EHSym, unsigned Num, unsigned P,
201 const std::vector<MachineMove> &M,
203 FunctionEHSym(EHSym), Number(Num), PersonalityIndex(P),
204 adjustsStack(hC), hasLandingPads(hL), Moves(M), function (f) { }
207 std::vector<FunctionEHFrameInfo> EHFrames;
209 /// UsesLSDA - Indicates whether an FDE that uses the CIE at the given index
210 /// uses an LSDA. If so, then we need to encode that information in the CIE's
212 DenseMap<unsigned, bool> UsesLSDA;
214 /// EmitCIE - Emit a Common Information Entry (CIE). This holds information
215 /// that is shared among many Frame Description Entries. There is at least
216 /// one CIE in every non-empty .debug_frame section.
217 void EmitCIE(const Function *Personality, unsigned Index);
219 /// EmitFDE - Emit the Frame Description Entry (FDE) for the function.
220 void EmitFDE(const FunctionEHFrameInfo &EHFrameInfo);
222 //===--------------------------------------------------------------------===//
223 // Main entry points.
225 DwarfTableException(AsmPrinter *A);
226 virtual ~DwarfTableException();
228 /// EndModule - Emit all exception information that should come after the
230 virtual void EndModule();
232 /// BeginFunction - Gather pre-function exception information. Assumes being
233 /// emitted immediately after the function entry point.
234 virtual void BeginFunction(const MachineFunction *MF);
236 /// EndFunction - Gather and emit post-function exception information.
237 virtual void EndFunction();
241 class ARMException : public DwarfException {
242 /// shouldEmitTable - Per-function flag to indicate if EH tables should
244 bool shouldEmitTable;
246 /// shouldEmitMoves - Per-function flag to indicate if frame moves info
247 /// should be emitted.
248 bool shouldEmitMoves;
250 /// shouldEmitTableModule - Per-module flag to indicate if EH tables
251 /// should be emitted.
252 bool shouldEmitTableModule;
254 //===--------------------------------------------------------------------===//
255 // Main entry points.
257 ARMException(AsmPrinter *A);
258 virtual ~ARMException();
260 /// EndModule - Emit all exception information that should come after the
262 virtual void EndModule();
264 /// BeginFunction - Gather pre-function exception information. Assumes being
265 /// emitted immediately after the function entry point.
266 virtual void BeginFunction(const MachineFunction *MF);
268 /// EndFunction - Gather and emit post-function exception information.
269 virtual void EndFunction();
272 } // End of namespace llvm