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