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Diffstat (limited to 'contrib/llvm/lib/CodeGen/AsmPrinter/DwarfException.h')
-rw-r--r-- | contrib/llvm/lib/CodeGen/AsmPrinter/DwarfException.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfException.h b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfException.h new file mode 100644 index 0000000..bc311e6 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfException.h @@ -0,0 +1,191 @@ +//===-- DwarfException.h - Dwarf Exception Framework -----------*- C++ -*--===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains support for writing dwarf exception info into asm files. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CODEGEN_ASMPRINTER_DWARFEXCEPTION_H +#define LLVM_CODEGEN_ASMPRINTER_DWARFEXCEPTION_H + +#include "llvm/ADT/DenseMap.h" +#include <vector> + +namespace llvm { + +template <typename T> class SmallVectorImpl; +struct LandingPadInfo; +class MachineModuleInfo; +class MachineMove; +class MachineInstr; +class MachineFunction; +class MCAsmInfo; +class MCExpr; +class MCSymbol; +class Function; +class AsmPrinter; + +//===----------------------------------------------------------------------===// +/// DwarfException - Emits Dwarf exception handling directives. +/// +class DwarfException { + /// Asm - Target of Dwarf emission. + AsmPrinter *Asm; + + /// MMI - Collected machine module information. + MachineModuleInfo *MMI; + + struct FunctionEHFrameInfo { + MCSymbol *FunctionEHSym; // L_foo.eh + unsigned Number; + unsigned PersonalityIndex; + bool adjustsStack; + bool hasLandingPads; + std::vector<MachineMove> Moves; + const Function *function; + + FunctionEHFrameInfo(MCSymbol *EHSym, unsigned Num, unsigned P, + bool hC, bool hL, + const std::vector<MachineMove> &M, + const Function *f): + FunctionEHSym(EHSym), Number(Num), PersonalityIndex(P), + adjustsStack(hC), hasLandingPads(hL), Moves(M), function (f) { } + }; + + std::vector<FunctionEHFrameInfo> EHFrames; + + /// UsesLSDA - Indicates whether an FDE that uses the CIE at the given index + /// uses an LSDA. If so, then we need to encode that information in the CIE's + /// augmentation. + DenseMap<unsigned, bool> UsesLSDA; + + /// shouldEmitTable - Per-function flag to indicate if EH tables should + /// be emitted. + bool shouldEmitTable; + + /// shouldEmitMoves - Per-function flag to indicate if frame moves info + /// should be emitted. + bool shouldEmitMoves; + + /// shouldEmitTableModule - Per-module flag to indicate if EH tables + /// should be emitted. + bool shouldEmitTableModule; + + /// shouldEmitFrameModule - Per-module flag to indicate if frame moves + /// should be emitted. + bool shouldEmitMovesModule; + + /// EmitCIE - Emit a Common Information Entry (CIE). This holds information + /// that is shared among many Frame Description Entries. There is at least + /// one CIE in every non-empty .debug_frame section. + void EmitCIE(const Function *Personality, unsigned Index); + + /// EmitFDE - Emit the Frame Description Entry (FDE) for the function. + void EmitFDE(const FunctionEHFrameInfo &EHFrameInfo); + + /// EmitExceptionTable - Emit landing pads and actions. + /// + /// The general organization of the table is complex, but the basic concepts + /// are easy. First there is a header which describes the location and + /// organization of the three components that follow. + /// 1. The landing pad site information describes the range of code covered + /// by the try. In our case it's an accumulation of the ranges covered + /// by the invokes in the try. There is also a reference to the landing + /// pad that handles the exception once processed. Finally an index into + /// the actions table. + /// 2. The action table, in our case, is composed of pairs of type ids + /// and next action offset. Starting with the action index from the + /// landing pad site, each type Id is checked for a match to the current + /// exception. If it matches then the exception and type id are passed + /// on to the landing pad. Otherwise the next action is looked up. This + /// chain is terminated with a next action of zero. If no type id is + /// found the frame is unwound and handling continues. + /// 3. Type id table contains references to all the C++ typeinfo for all + /// catches in the function. This tables is reversed indexed base 1. + + /// SharedTypeIds - How many leading type ids two landing pads have in common. + static unsigned SharedTypeIds(const LandingPadInfo *L, + const LandingPadInfo *R); + + /// PadLT - Order landing pads lexicographically by type id. + static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R); + + /// PadRange - Structure holding a try-range and the associated landing pad. + struct PadRange { + // The index of the landing pad. + unsigned PadIndex; + // The index of the begin and end labels in the landing pad's label lists. + unsigned RangeIndex; + }; + + typedef DenseMap<MCSymbol *, PadRange> RangeMapType; + + /// ActionEntry - Structure describing an entry in the actions table. + struct ActionEntry { + int ValueForTypeID; // The value to write - may not be equal to the type id. + int NextAction; + unsigned Previous; + }; + + /// CallSiteEntry - Structure describing an entry in the call-site table. + struct CallSiteEntry { + // The 'try-range' is BeginLabel .. EndLabel. + MCSymbol *BeginLabel; // zero indicates the start of the function. + MCSymbol *EndLabel; // zero indicates the end of the function. + + // The landing pad starts at PadLabel. + MCSymbol *PadLabel; // zero indicates that there is no landing pad. + unsigned Action; + }; + + /// ComputeActionsTable - Compute the actions table and gather the first + /// action index for each landing pad site. + unsigned ComputeActionsTable(const SmallVectorImpl<const LandingPadInfo*>&LPs, + SmallVectorImpl<ActionEntry> &Actions, + SmallVectorImpl<unsigned> &FirstActions); + + /// CallToNoUnwindFunction - Return `true' if this is a call to a function + /// marked `nounwind'. Return `false' otherwise. + bool CallToNoUnwindFunction(const MachineInstr *MI); + + /// ComputeCallSiteTable - Compute the call-site table. The entry for an + /// invoke has a try-range containing the call, a non-zero landing pad and an + /// appropriate action. The entry for an ordinary call has a try-range + /// containing the call and zero for the landing pad and the action. Calls + /// marked 'nounwind' have no entry and must not be contained in the try-range + /// of any entry - they form gaps in the table. Entries must be ordered by + /// try-range address. + void ComputeCallSiteTable(SmallVectorImpl<CallSiteEntry> &CallSites, + const RangeMapType &PadMap, + const SmallVectorImpl<const LandingPadInfo *> &LPs, + const SmallVectorImpl<unsigned> &FirstActions); + void EmitExceptionTable(); + +public: + //===--------------------------------------------------------------------===// + // Main entry points. + // + DwarfException(AsmPrinter *A); + ~DwarfException(); + + /// EndModule - Emit all exception information that should come after the + /// content. + void EndModule(); + + /// BeginFunction - Gather pre-function exception information. Assumes being + /// emitted immediately after the function entry point. + void BeginFunction(const MachineFunction *MF); + + /// EndFunction - Gather and emit post-function exception information. + void EndFunction(); +}; + +} // End of namespace llvm + +#endif |