LLVM  9.0.0svn
MSFCommon.h
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1 //===- MSFCommon.h - Common types and functions for MSF files ---*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_DEBUGINFO_MSF_MSFCOMMON_H
10 #define LLVM_DEBUGINFO_MSF_MSFCOMMON_H
11 
12 #include "llvm/ADT/ArrayRef.h"
13 #include "llvm/ADT/BitVector.h"
14 #include "llvm/Support/Endian.h"
15 #include "llvm/Support/Error.h"
17 #include <cstdint>
18 #include <vector>
19 
20 namespace llvm {
21 namespace msf {
22 
23 static const char Magic[] = {'M', 'i', 'c', 'r', 'o', 's', 'o', 'f',
24  't', ' ', 'C', '/', 'C', '+', '+', ' ',
25  'M', 'S', 'F', ' ', '7', '.', '0', '0',
26  '\r', '\n', '\x1a', 'D', 'S', '\0', '\0', '\0'};
27 
28 // The superblock is overlaid at the beginning of the file (offset 0).
29 // It starts with a magic header and is followed by information which
30 // describes the layout of the file system.
31 struct SuperBlock {
32  char MagicBytes[sizeof(Magic)];
33  // The file system is split into a variable number of fixed size elements.
34  // These elements are referred to as blocks. The size of a block may vary
35  // from system to system.
37  // The index of the free block map.
39  // This contains the number of blocks resident in the file system. In
40  // practice, NumBlocks * BlockSize is equivalent to the size of the MSF
41  // file.
43  // This contains the number of bytes which make up the directory.
45  // This field's purpose is not yet known.
47  // This contains the block # of the block map.
49 };
50 
51 struct MSFLayout {
52  MSFLayout() = default;
53 
55  assert(SB->FreeBlockMapBlock == 1 || SB->FreeBlockMapBlock == 2);
56  return SB->FreeBlockMapBlock;
57  }
58 
60  // If mainFpmBlock is 1, this is 2. If mainFpmBlock is 2, this is 1.
61  return 3U - mainFpmBlock();
62  }
63 
64  const SuperBlock *SB = nullptr;
68  std::vector<ArrayRef<support::ulittle32_t>> StreamMap;
69 };
70 
71 /// Describes the layout of a stream in an MSF layout. A "stream" here
72 /// is defined as any logical unit of data which may be arranged inside the MSF
73 /// file as a sequence of (possibly discontiguous) blocks. When we want to read
74 /// from a particular MSF Stream, we fill out a stream layout structure and the
75 /// reader uses it to determine which blocks in the underlying MSF file contain
76 /// the data, so that it can be pieced together in the right order.
78 public:
80  std::vector<support::ulittle32_t> Blocks;
81 };
82 
83 /// Determine the layout of the FPM stream, given the MSF layout. An FPM
84 /// stream spans 1 or more blocks, each at equally spaced intervals throughout
85 /// the file.
87  bool IncludeUnusedFpmData = false,
88  bool AltFpm = false);
89 
91  switch (Size) {
92  case 512:
93  case 1024:
94  case 2048:
95  case 4096:
96  return true;
97  }
98  return false;
99 }
100 
101 // Super Block, Fpm0, Fpm1, and Block Map
102 inline uint32_t getMinimumBlockCount() { return 4; }
103 
104 // Super Block, Fpm0, and Fpm1 are reserved. The Block Map, although required
105 // need not be at block 3.
106 inline uint32_t getFirstUnreservedBlock() { return 3; }
107 
108 inline uint64_t bytesToBlocks(uint64_t NumBytes, uint64_t BlockSize) {
109  return divideCeil(NumBytes, BlockSize);
110 }
111 
112 inline uint64_t blockToOffset(uint64_t BlockNumber, uint64_t BlockSize) {
113  return BlockNumber * BlockSize;
114 }
115 
117  return L.SB->BlockSize;
118 }
119 
120 /// Given an MSF with the specified block size and number of blocks, determine
121 /// how many pieces the specified Fpm is split into.
122 /// \p BlockSize - the block size of the MSF
123 /// \p NumBlocks - the total number of blocks in the MSF
124 /// \p IncludeUnusedFpmData - When true, this will count every block that is
125 /// both in the file and matches the form of an FPM block, even if some of
126 /// those FPM blocks are unused (a single FPM block can describe the
127 /// allocation status of up to 32,767 blocks, although one appears only
128 /// every 4,096 blocks). So there are 8x as many blocks that match the
129 /// form as there are blocks that are necessary to describe the allocation
130 /// status of the file. When this parameter is false, these extraneous
131 /// trailing blocks are not counted.
133  bool IncludeUnusedFpmData, int FpmNumber) {
134  assert(FpmNumber == 1 || FpmNumber == 2);
135  if (IncludeUnusedFpmData) {
136  // This calculation determines how many times a number of the form
137  // BlockSize * k + N appears in the range [0, NumBlocks). We only need to
138  // do this when unused data is included, since the number of blocks dwarfs
139  // the number of fpm blocks.
140  return divideCeil(NumBlocks - FpmNumber, BlockSize);
141  }
142 
143  // We want the minimum number of intervals required, where each interval can
144  // represent BlockSize * 8 blocks.
145  return divideCeil(NumBlocks, 8 * BlockSize);
146 }
147 
149  bool IncludeUnusedFpmData = false,
150  bool AltFpm = false) {
152  IncludeUnusedFpmData,
153  AltFpm ? L.alternateFpmBlock() : L.mainFpmBlock());
154 }
155 
157 
158 } // end namespace msf
159 } // end namespace llvm
160 
161 #endif // LLVM_DEBUGINFO_MSF_MSFCOMMON_H
char MagicBytes[sizeof(Magic)]
Definition: MSFCommon.h:32
This class represents lattice values for constants.
Definition: AllocatorList.h:23
Error validateSuperBlock(const SuperBlock &SB)
Definition: MSFCommon.cpp:19
uint64_t blockToOffset(uint64_t BlockNumber, uint64_t BlockSize)
Definition: MSFCommon.h:112
uint32_t getMinimumBlockCount()
Definition: MSFCommon.h:102
Describes the layout of a stream in an MSF layout.
Definition: MSFCommon.h:77
MSFStreamLayout getFpmStreamLayout(const MSFLayout &Msf, bool IncludeUnusedFpmData=false, bool AltFpm=false)
Determine the layout of the FPM stream, given the MSF layout.
Definition: MSFCommon.cpp:62
uint32_t getFpmIntervalLength(const MSFLayout &L)
Definition: MSFCommon.h:116
std::vector< support::ulittle32_t > Blocks
Definition: MSFCommon.h:80
uint32_t getNumFpmIntervals(uint32_t BlockSize, uint32_t NumBlocks, bool IncludeUnusedFpmData, int FpmNumber)
Given an MSF with the specified block size and number of blocks, determine how many pieces the specif...
Definition: MSFCommon.h:132
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:32
support::ulittle32_t BlockSize
Definition: MSFCommon.h:36
support::ulittle32_t BlockMapAddr
Definition: MSFCommon.h:48
static const char Magic[]
Definition: MSFCommon.h:23
support::ulittle32_t Unknown1
Definition: MSFCommon.h:46
uint32_t alternateFpmBlock() const
Definition: MSFCommon.h:59
ArrayRef< support::ulittle32_t > DirectoryBlocks
Definition: MSFCommon.h:66
BitVector FreePageMap
Definition: MSFCommon.h:65
uint64_t bytesToBlocks(uint64_t NumBytes, uint64_t BlockSize)
Definition: MSFCommon.h:108
uint32_t mainFpmBlock() const
Definition: MSFCommon.h:54
uint32_t Size
Definition: Profile.cpp:46
uint64_t divideCeil(uint64_t Numerator, uint64_t Denominator)
Returns the integer ceil(Numerator / Denominator).
Definition: MathExtras.h:698
std::vector< ArrayRef< support::ulittle32_t > > StreamMap
Definition: MSFCommon.h:68
ArrayRef< support::ulittle32_t > StreamSizes
Definition: MSFCommon.h:67
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
support::ulittle32_t FreeBlockMapBlock
Definition: MSFCommon.h:38
Lightweight error class with error context and mandatory checking.
Definition: Error.h:157
bool isValidBlockSize(uint32_t Size)
Definition: MSFCommon.h:90
uint32_t getFirstUnreservedBlock()
Definition: MSFCommon.h:106
const SuperBlock * SB
Definition: MSFCommon.h:64
support::ulittle32_t NumDirectoryBytes
Definition: MSFCommon.h:44
support::ulittle32_t NumBlocks
Definition: MSFCommon.h:42