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+//===-- 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
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