llvm-6502/include/llvm/MC/MCAsmLayout.h
Daniel Dunbar 0cc8bd4861 MC: Stop restarting layout on every relaxation.
- Still O(N^2), just a faster form, and now its the MCAsmLayout's fault.

On the .s I am tuning against (combine.s from 403.gcc):
--
ddunbar@lordcrumb:MC$ diff stats-before.txt stats-after.txt
5,10c5,10
<    1728 assembler - Number of assembler layout and relaxation steps
<    7707 assembler - Number of emitted assembler fragments
<  120588 assembler - Number of emitted object file bytes
< 2233448 assembler - Number of evaluated fixups
<    1727 assembler - Number of relaxed instructions
< 6723845 mcexpr    - Number of MCExpr evaluations
---
>      3 assembler - Number of assembler layout and relaxation steps
>   7707 assembler - Number of emitted assembler fragments
> 120588 assembler - Number of emitted object file bytes
>  14796 assembler - Number of evaluated fixups
>   1727 assembler - Number of relaxed instructions
>  67889 mcexpr    - Number of MCExpr evaluations
--
Feel free to LOL at the -before numbers, if you like.

I am a little surprised we make more than 2 relaxation passes. It's pretty
trivial for us to do relaxation out-of-order if that would give a speedup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99543 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-25 19:35:56 +00:00

98 lines
3.2 KiB
C++

//===- MCAsmLayout.h - Assembly Layout Object -------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCASMLAYOUT_H
#define LLVM_MC_MCASMLAYOUT_H
namespace llvm {
class MCAssembler;
class MCFragment;
class MCSectionData;
class MCSymbolData;
/// Encapsulates the layout of an assembly file at a particular point in time.
///
/// Assembly may requiring compute multiple layouts for a particular assembly
/// file as part of the relaxation process. This class encapsulates the layout
/// at a single point in time in such a way that it is always possible to
/// efficiently compute the exact addresses of any symbol in the assembly file,
/// even during the relaxation process.
class MCAsmLayout {
private:
MCAssembler &Assembler;
public:
MCAsmLayout(MCAssembler &_Assembler) : Assembler(_Assembler) {}
/// Get the assembler object this is a layout for.
MCAssembler &getAssembler() const { return Assembler; }
/// \brief Update the layout because a fragment has been resized. The
/// fragments size should have already been updated, the \arg SlideAmount is
/// the delta from the old size.
void UpdateForSlide(MCFragment *F, int SlideAmount);
/// @name Fragment Layout Data
/// @{
/// \brief Get the effective size of the given fragment, as computed in the
/// current layout.
uint64_t getFragmentEffectiveSize(const MCFragment *F) const;
/// \brief Set the effective size of the given fragment.
void setFragmentEffectiveSize(MCFragment *F, uint64_t Value);
/// \brief Get the offset of the given fragment inside its containing section.
uint64_t getFragmentOffset(const MCFragment *F) const;
/// \brief Set the offset of the given fragment inside its containing section.
void setFragmentOffset(MCFragment *F, uint64_t Value);
/// @}
/// @name Section Layout Data
/// @{
/// \brief Get the computed address of the given section.
uint64_t getSectionAddress(const MCSectionData *SD) const;
/// \brief Set the computed address of the given section.
void setSectionAddress(MCSectionData *SD, uint64_t Value);
/// \brief Get the data size of the given section, as emitted to the object
/// file. This may include additional padding, or be 0 for virtual sections.
uint64_t getSectionFileSize(const MCSectionData *SD) const;
/// \brief Set the data size of the given section.
void setSectionFileSize(MCSectionData *SD, uint64_t Value);
/// \brief Get the actual data size of the given section.
uint64_t getSectionSize(const MCSectionData *SD) const;
/// \brief Set the actual data size of the given section.
void setSectionSize(MCSectionData *SD, uint64_t Value);
/// @}
/// @name Utility Functions
/// @{
/// \brief Get the address of the given fragment, as computed in the current
/// layout.
uint64_t getFragmentAddress(const MCFragment *F) const;
/// \brief Get the address of the given symbol, as computed in the current
/// layout.
uint64_t getSymbolAddress(const MCSymbolData *SD) const;
/// @}
};
} // end namespace llvm
#endif