DwarfException.h revision 203954
1193323Sed//===-- DwarfException.h - Dwarf Exception Framework -----------*- C++ -*--===// 2193323Sed// 3193323Sed// The LLVM Compiler Infrastructure 4193323Sed// 5193323Sed// This file is distributed under the University of Illinois Open Source 6193323Sed// License. See LICENSE.TXT for details. 7193323Sed// 8193323Sed//===----------------------------------------------------------------------===// 9193323Sed// 10193323Sed// This file contains support for writing dwarf exception info into asm files. 11193323Sed// 12193323Sed//===----------------------------------------------------------------------===// 13193323Sed 14198090Srdivacky#ifndef LLVM_CODEGEN_ASMPRINTER_DWARFEXCEPTION_H 15198090Srdivacky#define LLVM_CODEGEN_ASMPRINTER_DWARFEXCEPTION_H 16193323Sed 17193323Sed#include "DIE.h" 18193323Sed#include "DwarfPrinter.h" 19193323Sed#include "llvm/CodeGen/AsmPrinter.h" 20193323Sed#include "llvm/ADT/DenseMap.h" 21193323Sed#include <string> 22193323Sed 23193323Sednamespace llvm { 24193323Sed 25193323Sedstruct LandingPadInfo; 26193323Sedclass MachineModuleInfo; 27198090Srdivackyclass MCAsmInfo; 28199481Srdivackyclass MCExpr; 29193323Sedclass Timer; 30193323Sedclass raw_ostream; 31193323Sed 32193323Sed//===----------------------------------------------------------------------===// 33193323Sed/// DwarfException - Emits Dwarf exception handling directives. 34193323Sed/// 35202878Srdivackyclass DwarfException : public DwarfPrinter { 36193323Sed struct FunctionEHFrameInfo { 37202878Srdivacky MCSymbol *FunctionEHSym; // L_foo.eh 38193323Sed unsigned Number; 39193323Sed unsigned PersonalityIndex; 40193323Sed bool hasCalls; 41193323Sed bool hasLandingPads; 42193323Sed std::vector<MachineMove> Moves; 43202878Srdivacky const Function *function; 44193323Sed 45202878Srdivacky FunctionEHFrameInfo(MCSymbol *EHSym, unsigned Num, unsigned P, 46193323Sed bool hC, bool hL, 47193323Sed const std::vector<MachineMove> &M, 48193323Sed const Function *f): 49202878Srdivacky FunctionEHSym(EHSym), Number(Num), PersonalityIndex(P), 50193323Sed hasCalls(hC), hasLandingPads(hL), Moves(M), function (f) { } 51193323Sed }; 52193323Sed 53193323Sed std::vector<FunctionEHFrameInfo> EHFrames; 54193323Sed 55198090Srdivacky /// UsesLSDA - Indicates whether an FDE that uses the CIE at the given index 56198090Srdivacky /// uses an LSDA. If so, then we need to encode that information in the CIE's 57198090Srdivacky /// augmentation. 58198090Srdivacky DenseMap<unsigned, bool> UsesLSDA; 59198090Srdivacky 60193323Sed /// shouldEmitTable - Per-function flag to indicate if EH tables should 61193323Sed /// be emitted. 62193323Sed bool shouldEmitTable; 63193323Sed 64193323Sed /// shouldEmitMoves - Per-function flag to indicate if frame moves info 65193323Sed /// should be emitted. 66193323Sed bool shouldEmitMoves; 67193323Sed 68193323Sed /// shouldEmitTableModule - Per-module flag to indicate if EH tables 69193323Sed /// should be emitted. 70193323Sed bool shouldEmitTableModule; 71193323Sed 72193323Sed /// shouldEmitFrameModule - Per-module flag to indicate if frame moves 73193323Sed /// should be emitted. 74193323Sed bool shouldEmitMovesModule; 75193323Sed 76193323Sed /// ExceptionTimer - Timer for the Dwarf exception writer. 77193323Sed Timer *ExceptionTimer; 78193323Sed 79198090Srdivacky /// EmitCIE - Emit a Common Information Entry (CIE). This holds information 80198090Srdivacky /// that is shared among many Frame Description Entries. There is at least 81198090Srdivacky /// one CIE in every non-empty .debug_frame section. 82198090Srdivacky void EmitCIE(const Function *Personality, unsigned Index); 83193323Sed 84198090Srdivacky /// EmitFDE - Emit the Frame Description Entry (FDE) for the function. 85198090Srdivacky void EmitFDE(const FunctionEHFrameInfo &EHFrameInfo); 86198090Srdivacky 87193323Sed /// EmitExceptionTable - Emit landing pads and actions. 88193323Sed /// 89193323Sed /// The general organization of the table is complex, but the basic concepts 90193323Sed /// are easy. First there is a header which describes the location and 91193323Sed /// organization of the three components that follow. 92193323Sed /// 1. The landing pad site information describes the range of code covered 93193323Sed /// by the try. In our case it's an accumulation of the ranges covered 94193323Sed /// by the invokes in the try. There is also a reference to the landing 95193323Sed /// pad that handles the exception once processed. Finally an index into 96193323Sed /// the actions table. 97193323Sed /// 2. The action table, in our case, is composed of pairs of type ids 98193323Sed /// and next action offset. Starting with the action index from the 99193323Sed /// landing pad site, each type Id is checked for a match to the current 100193323Sed /// exception. If it matches then the exception and type id are passed 101193323Sed /// on to the landing pad. Otherwise the next action is looked up. This 102193323Sed /// chain is terminated with a next action of zero. If no type id is 103203954Srdivacky /// found the frame is unwound and handling continues. 104193323Sed /// 3. Type id table contains references to all the C++ typeinfo for all 105193323Sed /// catches in the function. This tables is reversed indexed base 1. 106193323Sed 107193323Sed /// SharedTypeIds - How many leading type ids two landing pads have in common. 108193323Sed static unsigned SharedTypeIds(const LandingPadInfo *L, 109193323Sed const LandingPadInfo *R); 110193323Sed 111193323Sed /// PadLT - Order landing pads lexicographically by type id. 112193323Sed static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R); 113193323Sed 114193323Sed struct KeyInfo { 115193323Sed static inline unsigned getEmptyKey() { return -1U; } 116193323Sed static inline unsigned getTombstoneKey() { return -2U; } 117193323Sed static unsigned getHashValue(const unsigned &Key) { return Key; } 118193323Sed static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; } 119193323Sed }; 120193323Sed 121193323Sed /// PadRange - Structure holding a try-range and the associated landing pad. 122193323Sed struct PadRange { 123193323Sed // The index of the landing pad. 124193323Sed unsigned PadIndex; 125193323Sed // The index of the begin and end labels in the landing pad's label lists. 126193323Sed unsigned RangeIndex; 127193323Sed }; 128193323Sed 129193323Sed typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType; 130193323Sed 131198090Srdivacky /// ActionEntry - Structure describing an entry in the actions table. 132198090Srdivacky struct ActionEntry { 133198090Srdivacky int ValueForTypeID; // The value to write - may not be equal to the type id. 134198090Srdivacky int NextAction; 135203954Srdivacky unsigned Previous; 136198090Srdivacky }; 137198090Srdivacky 138193323Sed /// CallSiteEntry - Structure describing an entry in the call-site table. 139193323Sed struct CallSiteEntry { 140193323Sed // The 'try-range' is BeginLabel .. EndLabel. 141193323Sed unsigned BeginLabel; // zero indicates the start of the function. 142193323Sed unsigned EndLabel; // zero indicates the end of the function. 143198090Srdivacky 144193323Sed // The landing pad starts at PadLabel. 145193323Sed unsigned PadLabel; // zero indicates that there is no landing pad. 146193323Sed unsigned Action; 147193323Sed }; 148193323Sed 149198090Srdivacky /// ComputeActionsTable - Compute the actions table and gather the first 150198090Srdivacky /// action index for each landing pad site. 151198090Srdivacky unsigned ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*>&LPs, 152198090Srdivacky SmallVectorImpl<ActionEntry> &Actions, 153198090Srdivacky SmallVectorImpl<unsigned> &FirstActions); 154198090Srdivacky 155199481Srdivacky /// CallToNoUnwindFunction - Return `true' if this is a call to a function 156199481Srdivacky /// marked `nounwind'. Return `false' otherwise. 157199481Srdivacky bool CallToNoUnwindFunction(const MachineInstr *MI); 158199481Srdivacky 159198090Srdivacky /// ComputeCallSiteTable - Compute the call-site table. The entry for an 160198090Srdivacky /// invoke has a try-range containing the call, a non-zero landing pad and an 161198090Srdivacky /// appropriate action. The entry for an ordinary call has a try-range 162198090Srdivacky /// containing the call and zero for the landing pad and the action. Calls 163198090Srdivacky /// marked 'nounwind' have no entry and must not be contained in the try-range 164198090Srdivacky /// of any entry - they form gaps in the table. Entries must be ordered by 165198090Srdivacky /// try-range address. 166198090Srdivacky void ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites, 167198090Srdivacky const RangeMapType &PadMap, 168198090Srdivacky const SmallVectorImpl<const LandingPadInfo *> &LPs, 169198090Srdivacky const SmallVectorImpl<unsigned> &FirstActions); 170193323Sed void EmitExceptionTable(); 171193323Sed 172199481Srdivacky /// CreateLabelDiff - Emit a label and subtract it from the expression we 173199481Srdivacky /// already have. This is equivalent to emitting "foo - .", but we have to 174199481Srdivacky /// emit the label for "." directly. 175199481Srdivacky const MCExpr *CreateLabelDiff(const MCExpr *ExprRef, const char *LabelName, 176199481Srdivacky unsigned Index); 177193323Sedpublic: 178193323Sed //===--------------------------------------------------------------------===// 179193323Sed // Main entry points. 180193323Sed // 181198090Srdivacky DwarfException(raw_ostream &OS, AsmPrinter *A, const MCAsmInfo *T); 182193323Sed virtual ~DwarfException(); 183193323Sed 184193323Sed /// BeginModule - Emit all exception information that should come prior to the 185193323Sed /// content. 186195098Sed void BeginModule(Module *m, MachineModuleInfo *mmi) { 187195098Sed this->M = m; 188195098Sed this->MMI = mmi; 189193323Sed } 190193323Sed 191193323Sed /// EndModule - Emit all exception information that should come after the 192193323Sed /// content. 193193323Sed void EndModule(); 194193323Sed 195193323Sed /// BeginFunction - Gather pre-function exception information. Assumes being 196193323Sed /// emitted immediately after the function entry point. 197203954Srdivacky void BeginFunction(const MachineFunction *MF); 198193323Sed 199193323Sed /// EndFunction - Gather and emit post-function exception information. 200193323Sed void EndFunction(); 201193323Sed}; 202193323Sed 203193323Sed} // End of namespace llvm 204193323Sed 205193323Sed#endif 206