LCOV - code coverage report
Current view: top level - include/llvm/DebugInfo/MSF - MSFCommon.h (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 12 12 100.0 %
Date: 2018-07-13 00:08:38 Functions: 4 4 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===- MSFCommon.h - Common types and functions for MSF files ---*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : 
      10             : #ifndef LLVM_DEBUGINFO_MSF_MSFCOMMON_H
      11             : #define LLVM_DEBUGINFO_MSF_MSFCOMMON_H
      12             : 
      13             : #include "llvm/ADT/ArrayRef.h"
      14             : #include "llvm/ADT/BitVector.h"
      15             : #include "llvm/Support/Endian.h"
      16             : #include "llvm/Support/Error.h"
      17             : #include "llvm/Support/MathExtras.h"
      18             : #include <cstdint>
      19             : #include <vector>
      20             : 
      21             : namespace llvm {
      22             : namespace msf {
      23             : 
      24             : static const char Magic[] = {'M',  'i',  'c',    'r', 'o', 's',  'o',  'f',
      25             :                              't',  ' ',  'C',    '/', 'C', '+',  '+',  ' ',
      26             :                              'M',  'S',  'F',    ' ', '7', '.',  '0',  '0',
      27             :                              '\r', '\n', '\x1a', 'D', 'S', '\0', '\0', '\0'};
      28             : 
      29             : // The superblock is overlaid at the beginning of the file (offset 0).
      30             : // It starts with a magic header and is followed by information which
      31             : // describes the layout of the file system.
      32             : struct SuperBlock {
      33             :   char MagicBytes[sizeof(Magic)];
      34             :   // The file system is split into a variable number of fixed size elements.
      35             :   // These elements are referred to as blocks.  The size of a block may vary
      36             :   // from system to system.
      37             :   support::ulittle32_t BlockSize;
      38             :   // The index of the free block map.
      39             :   support::ulittle32_t FreeBlockMapBlock;
      40             :   // This contains the number of blocks resident in the file system.  In
      41             :   // practice, NumBlocks * BlockSize is equivalent to the size of the MSF
      42             :   // file.
      43             :   support::ulittle32_t NumBlocks;
      44             :   // This contains the number of bytes which make up the directory.
      45             :   support::ulittle32_t NumDirectoryBytes;
      46             :   // This field's purpose is not yet known.
      47             :   support::ulittle32_t Unknown1;
      48             :   // This contains the block # of the block map.
      49             :   support::ulittle32_t BlockMapAddr;
      50             : };
      51             : 
      52        1486 : struct MSFLayout {
      53         194 :   MSFLayout() = default;
      54             : 
      55             :   uint32_t mainFpmBlock() const {
      56             :     assert(SB->FreeBlockMapBlock == 1 || SB->FreeBlockMapBlock == 2);
      57             :     return SB->FreeBlockMapBlock;
      58             :   }
      59             : 
      60             :   uint32_t alternateFpmBlock() const {
      61             :     // If mainFpmBlock is 1, this is 2.  If mainFpmBlock is 2, this is 1.
      62         736 :     return 3U - mainFpmBlock();
      63             :   }
      64             : 
      65             :   const SuperBlock *SB = nullptr;
      66             :   BitVector FreePageMap;
      67             :   ArrayRef<support::ulittle32_t> DirectoryBlocks;
      68             :   ArrayRef<support::ulittle32_t> StreamSizes;
      69             :   std::vector<ArrayRef<support::ulittle32_t>> StreamMap;
      70             : };
      71             : 
      72             : /// Describes the layout of a stream in an MSF layout.  A "stream" here
      73             : /// is defined as any logical unit of data which may be arranged inside the MSF
      74             : /// file as a sequence of (possibly discontiguous) blocks.  When we want to read
      75             : /// from a particular MSF Stream, we fill out a stream layout structure and the
      76             : /// reader uses it to determine which blocks in the underlying MSF file contain
      77             : /// the data, so that it can be pieced together in the right order.
      78        2683 : class MSFStreamLayout {
      79             : public:
      80             :   uint32_t Length;
      81             :   std::vector<support::ulittle32_t> Blocks;
      82             : };
      83             : 
      84             : /// Determine the layout of the FPM stream, given the MSF layout.  An FPM
      85             : /// stream spans 1 or more blocks, each at equally spaced intervals throughout
      86             : /// the file.
      87             : MSFStreamLayout getFpmStreamLayout(const MSFLayout &Msf,
      88             :                                    bool IncludeUnusedFpmData = false,
      89             :                                    bool AltFpm = false);
      90             : 
      91             : inline bool isValidBlockSize(uint32_t Size) {
      92         213 :   switch (Size) {
      93             :   case 512:
      94             :   case 1024:
      95             :   case 2048:
      96             :   case 4096:
      97             :     return true;
      98             :   }
      99             :   return false;
     100             : }
     101             : 
     102             : // Super Block, Fpm0, Fpm1, and Block Map
     103             : inline uint32_t getMinimumBlockCount() { return 4; }
     104             : 
     105             : // Super Block, Fpm0, and Fpm1 are reserved.  The Block Map, although required
     106             : // need not be at block 3.
     107             : inline uint32_t getFirstUnreservedBlock() { return 3; }
     108             : 
     109             : inline uint64_t bytesToBlocks(uint64_t NumBytes, uint64_t BlockSize) {
     110             :   return divideCeil(NumBytes, BlockSize);
     111             : }
     112             : 
     113             : inline uint64_t blockToOffset(uint64_t BlockNumber, uint64_t BlockSize) {
     114       36443 :   return BlockNumber * BlockSize;
     115             : }
     116             : 
     117             : inline uint32_t getFpmIntervalLength(const MSFLayout &L) {
     118             :   return L.SB->BlockSize;
     119             : }
     120             : 
     121             : /// Given an MSF with the specified block size and number of blocks, determine
     122             : /// how many pieces the specified Fpm is split into.
     123             : /// \p BlockSize - the block size of the MSF
     124             : /// \p NumBlocks - the total number of blocks in the MSF
     125             : /// \p IncludeUnusedFpmData - When true, this will count every block that is
     126             : ///    both in the file and matches the form of an FPM block, even if some of
     127             : ///    those FPM blocks are unused (a single FPM block can describe the
     128             : ///    allocation status of up to 32,767 blocks, although one appears only
     129             : ///    every 4,096 blocks).  So there are 8x as many blocks that match the
     130             : ///    form as there are blocks that are necessary to describe the allocation
     131             : ///    status of the file.  When this parameter is false, these extraneous
     132             : ///    trailing blocks are not counted.
     133             : inline uint32_t getNumFpmIntervals(uint32_t BlockSize, uint32_t NumBlocks,
     134             :                                    bool IncludeUnusedFpmData, int FpmNumber) {
     135             :   assert(FpmNumber == 1 || FpmNumber == 2);
     136         474 :   if (IncludeUnusedFpmData) {
     137             :     // This calculation determines how many times a number of the form
     138             :     // BlockSize * k + N appears in the range [0, NumBlocks).  We only need to
     139             :     // do this when unused data is included, since the number of blocks dwarfs
     140             :     // the number of fpm blocks.
     141         380 :     return divideCeil(NumBlocks - FpmNumber, BlockSize);
     142             :   }
     143             : 
     144             :   // We want the minimum number of intervals required, where each interval can
     145             :   // represent BlockSize * 8 blocks.
     146         596 :   return divideCeil(NumBlocks, 8 * BlockSize);
     147             : }
     148             : 
     149         474 : inline uint32_t getNumFpmIntervals(const MSFLayout &L,
     150             :                                    bool IncludeUnusedFpmData = false,
     151             :                                    bool AltFpm = false) {
     152         948 :   return getNumFpmIntervals(L.SB->BlockSize, L.SB->NumBlocks,
     153             :                             IncludeUnusedFpmData,
     154         771 :                             AltFpm ? L.alternateFpmBlock() : L.mainFpmBlock());
     155             : }
     156             : 
     157             : Error validateSuperBlock(const SuperBlock &SB);
     158             : 
     159             : } // end namespace msf
     160             : } // end namespace llvm
     161             : 
     162             : #endif // LLVM_DEBUGINFO_MSF_MSFCOMMON_H

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