1//===- MSFCommon.cpp - Common types and functions for MSF files -----------===//
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#include "llvm/DebugInfo/MSF/MSFCommon.h"
10#include "llvm/DebugInfo/MSF/MSFError.h"
11#include "llvm/Support/Endian.h"
12#include "llvm/Support/Error.h"
13#include <cstdint>
14#include <cstring>
15
16using namespace llvm;
17using namespace llvm::msf;
18
19Error llvm::msf::validateSuperBlock(const SuperBlock &SB) {
20  // Check the magic bytes.
21  if (std::memcmp(SB.MagicBytes, Magic, sizeof(Magic)) != 0)
22    return make_error<MSFError>(msf_error_code::invalid_format,
23                                "MSF magic header doesn't match");
24
25  if (!isValidBlockSize(SB.BlockSize))
26    return make_error<MSFError>(msf_error_code::invalid_format,
27                                "Unsupported block size.");
28
29  // We don't support directories whose sizes aren't a multiple of four bytes.
30  if (SB.NumDirectoryBytes % sizeof(support::ulittle32_t) != 0)
31    return make_error<MSFError>(msf_error_code::invalid_format,
32                                "Directory size is not multiple of 4.");
33
34  // The number of blocks which comprise the directory is a simple function of
35  // the number of bytes it contains.
36  uint64_t NumDirectoryBlocks =
37      bytesToBlocks(SB.NumDirectoryBytes, SB.BlockSize);
38
39  // The directory, as we understand it, is a block which consists of a list of
40  // block numbers.  It is unclear what would happen if the number of blocks
41  // couldn't fit on a single block.
42  if (NumDirectoryBlocks > SB.BlockSize / sizeof(support::ulittle32_t))
43    return make_error<MSFError>(msf_error_code::invalid_format,
44                                "Too many directory blocks.");
45
46  if (SB.BlockMapAddr == 0)
47    return make_error<MSFError>(msf_error_code::invalid_format,
48                                "Block 0 is reserved");
49
50  if (SB.BlockMapAddr >= SB.NumBlocks)
51    return make_error<MSFError>(msf_error_code::invalid_format,
52                                "Block map address is invalid.");
53
54  if (SB.FreeBlockMapBlock != 1 && SB.FreeBlockMapBlock != 2)
55    return make_error<MSFError>(
56        msf_error_code::invalid_format,
57        "The free block map isn't at block 1 or block 2.");
58
59  return Error::success();
60}
61
62MSFStreamLayout llvm::msf::getFpmStreamLayout(const MSFLayout &Msf,
63                                              bool IncludeUnusedFpmData,
64                                              bool AltFpm) {
65  MSFStreamLayout FL;
66  uint32_t NumFpmIntervals =
67      getNumFpmIntervals(Msf, IncludeUnusedFpmData, AltFpm);
68
69  uint32_t FpmBlock = AltFpm ? Msf.alternateFpmBlock() : Msf.mainFpmBlock();
70
71  for (uint32_t I = 0; I < NumFpmIntervals; ++I) {
72    FL.Blocks.push_back(support::ulittle32_t(FpmBlock));
73    FpmBlock += msf::getFpmIntervalLength(Msf);
74  }
75
76  if (IncludeUnusedFpmData)
77    FL.Length = NumFpmIntervals * Msf.SB->BlockSize;
78  else
79    FL.Length = divideCeil(Msf.SB->NumBlocks, 8);
80
81  return FL;
82}
83