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 21 namespace llvm { 22 23 template <typename T> class SmallVectorImpl; 24 struct LandingPadInfo; 25 class MachineModuleInfo; 26 class MachineMove; 27 class MachineInstr; 28 class MachineFunction; 29 class MCAsmInfo; 30 class MCExpr; 31 class MCSymbol; 32 class Function; 33 class AsmPrinter; 34 35 //===----------------------------------------------------------------------===// 36 /// DwarfException - Emits Dwarf exception handling directives. 37 /// 38 class DwarfException { 39 protected: 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 public: 125 //===--------------------------------------------------------------------===// 126 // Main entry points. 127 // 128 DwarfException(AsmPrinter *A); 129 virtual ~DwarfException(); 130 131 /// EndModule - Emit all exception information that should come after the 132 /// content. 133 virtual void EndModule(); 134 135 /// BeginFunction - Gather pre-function exception information. Assumes being 136 /// emitted immediately after the function entry point. 137 virtual void BeginFunction(const MachineFunction *MF); 138 139 /// EndFunction - Gather and emit post-function exception information. 140 virtual void EndFunction(); 141 }; 142 143 class DwarfCFIException : public DwarfException { 144 /// shouldEmitPersonality - Per-function flag to indicate if .cfi_personality 145 /// should be emitted. 146 bool shouldEmitPersonality; 147 148 /// shouldEmitLSDA - Per-function flag to indicate if .cfi_lsda 149 /// should be emitted. 150 bool shouldEmitLSDA; 151 152 /// shouldEmitMoves - Per-function flag to indicate if frame moves info 153 /// should be emitted. 154 bool shouldEmitMoves; 155 156 AsmPrinter::CFIMoveType moveTypeModule; 157 158 public: 159 //===--------------------------------------------------------------------===// 160 // Main entry points. 161 // 162 DwarfCFIException(AsmPrinter *A); 163 virtual ~DwarfCFIException(); 164 165 /// EndModule - Emit all exception information that should come after the 166 /// content. 167 virtual void EndModule(); 168 169 /// BeginFunction - Gather pre-function exception information. Assumes being 170 /// emitted immediately after the function entry point. 171 virtual void BeginFunction(const MachineFunction *MF); 172 173 /// EndFunction - Gather and emit post-function exception information. 174 virtual void EndFunction(); 175 }; 176 177 class ARMException : public DwarfException { 178 public: 179 //===--------------------------------------------------------------------===// 180 // Main entry points. 181 // 182 ARMException(AsmPrinter *A); 183 virtual ~ARMException(); 184 185 /// EndModule - Emit all exception information that should come after the 186 /// content. 187 virtual void EndModule(); 188 189 /// BeginFunction - Gather pre-function exception information. Assumes being 190 /// emitted immediately after the function entry point. 191 virtual void BeginFunction(const MachineFunction *MF); 192 193 /// EndFunction - Gather and emit post-function exception information. 194 virtual void EndFunction(); 195 }; 196 197 class Win64Exception : public DwarfException { 198 /// shouldEmitPersonality - Per-function flag to indicate if personality 199 /// info should be emitted. 200 bool shouldEmitPersonality; 201 202 /// shouldEmitLSDA - Per-function flag to indicate if the LSDA 203 /// should be emitted. 204 bool shouldEmitLSDA; 205 206 /// shouldEmitMoves - Per-function flag to indicate if frame moves info 207 /// should be emitted. 208 bool shouldEmitMoves; 209 210 public: 211 //===--------------------------------------------------------------------===// 212 // Main entry points. 213 // 214 Win64Exception(AsmPrinter *A); 215 virtual ~Win64Exception(); 216 217 /// EndModule - Emit all exception information that should come after the 218 /// content. 219 virtual void EndModule(); 220 221 /// BeginFunction - Gather pre-function exception information. Assumes being 222 /// emitted immediately after the function entry point. 223 virtual void BeginFunction(const MachineFunction *MF); 224 225 /// EndFunction - Gather and emit post-function exception information. 226 virtual void EndFunction(); 227 }; 228 229 } // End of namespace llvm 230 231 #endif 232
