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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 CODEGEN_ASMPRINTER_DWARFEXCEPTION_H__
#define CODEGEN_ASMPRINTER_DWARFEXCEPTION_H__
#include "DIE.h"
#include "DwarfPrinter.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/ADT/DenseMap.h"
#include <string>
namespace llvm {
struct LandingPadInfo;
class MachineModuleInfo;
class TargetAsmInfo;
class Timer;
class raw_ostream;
//===----------------------------------------------------------------------===//
/// DwarfException - Emits Dwarf exception handling directives.
///
class VISIBILITY_HIDDEN DwarfException : public Dwarf {
struct FunctionEHFrameInfo {
std::string FnName;
unsigned Number;
unsigned PersonalityIndex;
bool hasCalls;
bool hasLandingPads;
std::vector<MachineMove> Moves;
const Function * function;
FunctionEHFrameInfo(const std::string &FN, unsigned Num, unsigned P,
bool hC, bool hL,
const std::vector<MachineMove> &M,
const Function *f):
FnName(FN), Number(Num), PersonalityIndex(P),
hasCalls(hC), hasLandingPads(hL), Moves(M), function (f) { }
};
std::vector<FunctionEHFrameInfo> EHFrames;
/// 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;
/// ExceptionTimer - Timer for the Dwarf exception writer.
Timer *ExceptionTimer;
/// EmitCommonEHFrame - Emit the common eh unwind frame.
///
void EmitCommonEHFrame(const Function *Personality, unsigned Index);
/// EmitEHFrame - Emit function exception frame information.
///
void EmitEHFrame(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 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);
struct KeyInfo {
static inline unsigned getEmptyKey() { return -1U; }
static inline unsigned getTombstoneKey() { return -2U; }
static unsigned getHashValue(const unsigned &Key) { return Key; }
static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
static bool isPod() { return true; }
};
/// 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;
struct ActionEntry *Previous;
};
/// 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<unsigned, PadRange, KeyInfo> RangeMapType;
/// CallSiteEntry - Structure describing an entry in the call-site table.
struct CallSiteEntry {
// The 'try-range' is BeginLabel .. EndLabel.
unsigned BeginLabel; // zero indicates the start of the function.
unsigned EndLabel; // zero indicates the end of the function.
// The landing pad starts at PadLabel.
unsigned PadLabel; // zero indicates that there is no landing pad.
unsigned Action;
};
void EmitExceptionTable();
public:
//===--------------------------------------------------------------------===//
// Main entry points.
//
DwarfException(raw_ostream &OS, AsmPrinter *A, const TargetAsmInfo *T);
virtual ~DwarfException();
/// BeginModule - Emit all exception information that should come prior to the
/// content.
void BeginModule(Module *m, MachineModuleInfo *mmi) {
this->M = m;
this->MMI = mmi;
}
/// 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(MachineFunction *MF);
/// EndFunction - Gather and emit post-function exception information.
void EndFunction();
};
} // End of namespace llvm
#endif
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