llvm-6502/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h
Adrian Prantl 2a39c993eb Debug info: Infrastructure to support debug locations for fragmented
variables (for example, by-value struct arguments passed in registers, or
large integer values split across several smaller registers).
On the IR level, this adds a new type of complex address operation OpPiece
to DIVariable that describes size and offset of a variable fragment.
On the DWARF emitter level, all pieces describing the same variable are
collected, sorted and emitted as DWARF expressions using the DW_OP_piece
and DW_OP_bit_piece operators.

http://reviews.llvm.org/D3373
rdar://problem/15928306

What this patch doesn't do / Future work:
- This patch only adds the backend machinery to make this work, patches
  that change SROA and SelectionDAG's type legalizer to actually create
  such debug info will follow. (http://reviews.llvm.org/D2680)
- Making the DIVariable complex expressions into an argument of dbg.value
  will reduce the memory footprint of the debug metadata.
- The sorting/uniquing of pieces should be moved into DebugLocEntry,
  to facilitate the merging of multi-piece entries.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214576 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-01 22:11:58 +00:00

57 lines
2.1 KiB
C++

//===-- llvm/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h ----*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef CODEGEN_ASMPRINTER_DBGVALUEHISTORYCALCULATOR_H_
#define CODEGEN_ASMPRINTER_DBGVALUEHISTORYCALCULATOR_H_
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SmallVector.h"
namespace llvm {
class MachineFunction;
class MachineInstr;
class MDNode;
class TargetRegisterInfo;
// For each user variable, keep a list of instruction ranges where this variable
// is accessible. The variables are listed in order of appearance.
class DbgValueHistoryMap {
// Each instruction range starts with a DBG_VALUE instruction, specifying the
// location of a variable, which is assumed to be valid until the end of the
// range. If end is not specified, location is valid until the start
// instruction of the next instruction range, or until the end of the
// function.
public:
typedef std::pair<const MachineInstr *, const MachineInstr *> InstrRange;
typedef SmallVector<InstrRange, 4> InstrRanges;
typedef MapVector<const MDNode *, InstrRanges> InstrRangesMap;
private:
InstrRangesMap VarInstrRanges;
public:
void startInstrRange(const MDNode *Var, const MachineInstr &MI);
void endInstrRange(const MDNode *Var, const MachineInstr &MI);
// Returns register currently describing @Var. If @Var is currently
// unaccessible or is not described by a register, returns 0.
unsigned getRegisterForVar(const MDNode *Var) const;
bool empty() const { return VarInstrRanges.empty(); }
void clear() { VarInstrRanges.clear(); }
InstrRangesMap::const_iterator begin() const { return VarInstrRanges.begin(); }
InstrRangesMap::const_iterator end() const { return VarInstrRanges.end(); }
};
void calculateDbgValueHistory(const MachineFunction *MF,
const TargetRegisterInfo *TRI,
DbgValueHistoryMap &Result);
}
#endif