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Optimize loading of Relocation/Symbol tables
1 parent dcfc2fb commit 0c6bcb3

9 files changed

+237
-95
lines changed

‎src/LibObjectFile.Bench/LibObjectFile.Bench.csproj

+14
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
<Project Sdk="Microsoft.NET.Sdk">
2+
3+
<PropertyGroup>
4+
<OutputType>Exe</OutputType>
5+
<TargetFramework>net8.0</TargetFramework>
6+
<ImplicitUsings>enable</ImplicitUsings>
7+
<Nullable>enable</Nullable>
8+
</PropertyGroup>
9+
10+
<ItemGroup>
11+
<ProjectReference Include="..\LibObjectFile\LibObjectFile.csproj" />
12+
</ItemGroup>
13+
14+
</Project>

‎src/LibObjectFile.Bench/Program.cs

+58
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,58 @@
1+
// Copyright (c) Alexandre Mutel. All rights reserved.
2+
// This file is licensed under the BSD-Clause 2 license.
3+
// See the license.txt file in the project root for more information.
4+
5+
using System.Diagnostics;
6+
using LibObjectFile.Elf;
7+
8+
namespace LibObjectFile.Bench;
9+
10+
internal class Program
11+
{
12+
static void Main(string[] args)
13+
{
14+
var clock = Stopwatch.StartNew();
15+
//var memoryStream = new MemoryStream();
16+
foreach (var file in GetLinuxBins())
17+
{
18+
//memoryStream.SetLength(0);
19+
using var stream = File.OpenRead((string)file[0]);
20+
//stream.CopyTo(memoryStream);
21+
22+
if (ElfFile.IsElf(stream))
23+
{
24+
ElfFile.Read(stream);
25+
}
26+
}
27+
clock.Stop();
28+
Console.WriteLine($"{clock.Elapsed.TotalMilliseconds}ms");
29+
}
30+
31+
public static IEnumerable<object[]> GetLinuxBins()
32+
{
33+
var wslDirectory = @"\\wsl$\Ubuntu\usr\bin";
34+
if (OperatingSystem.IsLinux())
35+
{
36+
foreach (var file in Directory.EnumerateFiles(@"/usr/bin"))
37+
{
38+
yield return new object[] { file };
39+
}
40+
}
41+
else if (OperatingSystem.IsWindows() && Directory.Exists(wslDirectory))
42+
{
43+
foreach (var file in Directory.EnumerateFiles(wslDirectory))
44+
{
45+
var fileInfo = new FileInfo(file);
46+
// Skip symbolic links as loading them will fail
47+
if ((fileInfo.Attributes & FileAttributes.ReparsePoint) == 0)
48+
{
49+
yield return new object[] { file };
50+
}
51+
}
52+
}
53+
else
54+
{
55+
yield return new object[] { string.Empty };
56+
}
57+
}
58+
}

‎src/LibObjectFile.sln

+6
Original file line numberDiff line numberDiff line change
@@ -30,6 +30,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "doc", "doc", "{BD580DD4-4E2
3030
EndProject
3131
Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "objdasm", "objdasm\objdasm.csproj", "{056AA737-6B5F-47A6-8426-E7918D930C5C}"
3232
EndProject
33+
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LibObjectFile.Bench", "LibObjectFile.Bench\LibObjectFile.Bench.csproj", "{34AD50B2-FAE3-42C9-8117-B5DE1CEEF0EA}"
34+
EndProject
3335
Global
3436
GlobalSection(SolutionConfigurationPlatforms) = preSolution
3537
Debug|Any CPU = Debug|Any CPU
@@ -52,6 +54,10 @@ Global
5254
{056AA737-6B5F-47A6-8426-E7918D930C5C}.Debug|Any CPU.Build.0 = Debug|Any CPU
5355
{056AA737-6B5F-47A6-8426-E7918D930C5C}.Release|Any CPU.ActiveCfg = Release|Any CPU
5456
{056AA737-6B5F-47A6-8426-E7918D930C5C}.Release|Any CPU.Build.0 = Release|Any CPU
57+
{34AD50B2-FAE3-42C9-8117-B5DE1CEEF0EA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
58+
{34AD50B2-FAE3-42C9-8117-B5DE1CEEF0EA}.Debug|Any CPU.Build.0 = Debug|Any CPU
59+
{34AD50B2-FAE3-42C9-8117-B5DE1CEEF0EA}.Release|Any CPU.ActiveCfg = Release|Any CPU
60+
{34AD50B2-FAE3-42C9-8117-B5DE1CEEF0EA}.Release|Any CPU.Build.0 = Release|Any CPU
5561
EndGlobalSection
5662
GlobalSection(SolutionProperties) = preSolution
5763
HideSolutionNode = FALSE

‎src/LibObjectFile/Elf/Sections/ElfRelocation.cs

+1-1
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@ namespace LibObjectFile.Elf;
88
/// A relocation entry in the <see cref="ElfRelocationTable"/>
99
/// This is the value seen in <see cref="ElfNative.Elf32_Rel"/> or <see cref="ElfNative.Elf64_Rel"/>
1010
/// </summary>
11-
public record ElfRelocation
11+
public record struct ElfRelocation
1212
{
1313
public ElfRelocation()
1414
{

‎src/LibObjectFile/Elf/Sections/ElfRelocationTable.cs

+47-62
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,10 @@
44

55
using System;
66
using System.Collections.Generic;
7+
using System.Runtime.CompilerServices;
8+
using System.Runtime.InteropServices;
79
using LibObjectFile.Diagnostics;
10+
using LibObjectFile.IO;
811

912
namespace LibObjectFile.Elf;
1013

@@ -63,95 +66,77 @@ public override void Write(ElfWriter writer)
6366
private unsafe void Read32(ElfReader reader)
6467
{
6568
var numberOfEntries = base.Size / base.TableEntrySize;
66-
_entries.Capacity = (int)numberOfEntries;
69+
var entries = _entries;
70+
CollectionsMarshal.SetCount(entries, (int)numberOfEntries);
71+
var span = CollectionsMarshal.AsSpan(entries);
72+
6773
if (IsRelocationWithAddends)
6874
{
69-
for (ulong i = 0; i < numberOfEntries; i++)
75+
using var batch = new BatchDataReader<ElfNative.Elf32_Rela>(reader.Stream, (int)numberOfEntries);
76+
ref var entry = ref MemoryMarshal.GetReference(span);
77+
while (batch.HasNext())
7078
{
71-
ElfNative.Elf32_Rela rel;
72-
ulong streamOffset = (ulong)reader.Stream.Position;
73-
if (!reader.TryReadData(sizeof(ElfNative.Elf32_Rela), out rel))
74-
{
75-
reader.Diagnostics.Error(DiagnosticId.ELF_ERR_IncompleteRelocationAddendsEntry32Size, $"Unable to read entirely the relocation entry [{i}] from {Type} section [{Index}]. Not enough data (size: {base.TableEntrySize}) read at offset {streamOffset} from the stream");
76-
}
77-
78-
var offset = reader.Decode(rel.r_offset);
79+
ref var rel = ref batch.ReadNext();
80+
entry.Offset = reader.Decode(rel.r_offset);
7981
var r_info = reader.Decode(rel.r_info);
80-
var type = new ElfRelocationType(Parent!.Arch, r_info & 0xFF);
81-
var symbolIndex = r_info >> 8;
82-
var addend = reader.Decode(rel.r_addend);
83-
84-
var entry = new ElfRelocation(offset, type, symbolIndex, addend);
85-
_entries.Add(entry);
82+
entry.Type = new ElfRelocationType(Parent!.Arch, r_info & 0xFF);
83+
entry.SymbolIndex = r_info >> 8;
84+
entry.Addend = reader.Decode(rel.r_addend);
85+
entry = ref Unsafe.Add(ref entry, 1);
8686
}
8787
}
8888
else
8989
{
90-
for (ulong i = 0; i < numberOfEntries; i++)
90+
using var batch = new BatchDataReader<ElfNative.Elf32_Rel>(reader.Stream, (int)numberOfEntries);
91+
ref var entry = ref MemoryMarshal.GetReference(span);
92+
while (batch.HasNext())
9193
{
92-
ElfNative.Elf32_Rel rel;
93-
ulong streamOffset = (ulong)reader.Stream.Position;
94-
if (!reader.TryReadData(sizeof(ElfNative.Elf32_Rel), out rel))
95-
{
96-
reader.Diagnostics.Error(DiagnosticId.ELF_ERR_IncompleteRelocationEntry32Size, $"Unable to read entirely the relocation entry [{i}] from {Type} section [{Index}]. Not enough data (size: {base.TableEntrySize}) read at offset {streamOffset} from the stream");
97-
}
98-
99-
var offset = reader.Decode(rel.r_offset);
100-
94+
ref var rel = ref batch.ReadNext();
95+
entry.Offset = reader.Decode(rel.r_offset);
10196
var r_info = reader.Decode(rel.r_info);
102-
var type = new ElfRelocationType(Parent!.Arch, r_info & 0xFF);
103-
var symbolIndex = r_info >> 8;
104-
105-
var entry = new ElfRelocation(offset, type, symbolIndex, 0);
106-
_entries.Add(entry);
97+
entry.Type = new ElfRelocationType(Parent!.Arch, r_info & 0xFF);
98+
entry.SymbolIndex = r_info >> 8;
99+
entry.Addend = 0;
100+
entry = ref Unsafe.Add(ref entry, 1);
107101
}
108102
}
109103
}
110104

111105
private unsafe void Read64(ElfReader reader)
112106
{
113107
var numberOfEntries = base.Size / base.TableEntrySize;
108+
var entries = _entries;
109+
CollectionsMarshal.SetCount(entries, (int)numberOfEntries);
110+
var span = CollectionsMarshal.AsSpan(entries);
111+
114112
if (IsRelocationWithAddends)
115113
{
116-
for (ulong i = 0; i < numberOfEntries; i++)
114+
using var batch = new BatchDataReader<ElfNative.Elf64_Rela>(reader.Stream, (int)numberOfEntries);
115+
ref var entry = ref MemoryMarshal.GetReference(span);
116+
while (batch.HasNext())
117117
{
118-
ElfNative.Elf64_Rela rel;
119-
ulong streamOffset = (ulong)reader.Stream.Position;
120-
if (!reader.TryReadData(sizeof(ElfNative.Elf64_Rela), out rel))
121-
{
122-
reader.Diagnostics.Error(DiagnosticId.ELF_ERR_IncompleteRelocationAddendsEntry64Size, $"Unable to read entirely the relocation entry [{i}] from {Type} section [{Index}]. Not enough data (size: {base.TableEntrySize}) read at offset {streamOffset} from the stream");
123-
}
124-
125-
var offset = reader.Decode(rel.r_offset);
126-
118+
ref var rel = ref batch.ReadNext();
119+
entry.Offset = reader.Decode(rel.r_offset);
127120
var r_info = reader.Decode(rel.r_info);
128-
var type = new ElfRelocationType(Parent!.Arch, (uint)(r_info & 0xFFFFFFFF));
129-
var symbolIndex = (uint)(r_info >> 32);
130-
var addend = reader.Decode(rel.r_addend);
131-
132-
var entry = new ElfRelocation(offset, type, symbolIndex, addend);
133-
_entries.Add(entry);
121+
entry.Type = new ElfRelocationType(Parent!.Arch, (uint)(r_info & 0xFFFFFFFF));
122+
entry.SymbolIndex = (uint)(r_info >> 32);
123+
entry.Addend = reader.Decode(rel.r_addend);
124+
entry = ref Unsafe.Add(ref entry, 1);
134125
}
135126
}
136127
else
137128
{
138-
for (ulong i = 0; i < numberOfEntries; i++)
129+
using var batch = new BatchDataReader<ElfNative.Elf64_Rel>(reader.Stream, (int)numberOfEntries);
130+
ref var entry = ref MemoryMarshal.GetReference(span);
131+
while (batch.HasNext())
139132
{
140-
ElfNative.Elf64_Rel rel;
141-
ulong streamOffset = (ulong)reader.Stream.Position;
142-
if (!reader.TryReadData(sizeof(ElfNative.Elf64_Rel), out rel))
143-
{
144-
reader.Diagnostics.Error(DiagnosticId.ELF_ERR_IncompleteRelocationEntry64Size, $"Unable to read entirely the relocation entry [{i}] from {Type} section [{Index}]. Not enough data (size: {base.TableEntrySize}) read at offset {streamOffset} from the stream");
145-
}
146-
147-
var offset = reader.Decode(rel.r_offset);
148-
133+
ref var rel = ref batch.ReadNext();
134+
entry.Offset = reader.Decode(rel.r_offset);
149135
var r_info = reader.Decode(rel.r_info);
150-
var type = new ElfRelocationType(Parent!.Arch, (uint)(r_info & 0xFFFFFFFF));
151-
var symbolIndex = (uint)(r_info >> 32);
152-
153-
var entry = new ElfRelocation(offset, type, symbolIndex, 0);
154-
_entries.Add(entry);
136+
entry.Type = new ElfRelocationType(Parent!.Arch, (uint)(r_info & 0xFFFFFFFF));
137+
entry.SymbolIndex = (uint)(r_info >> 32);
138+
entry.Addend = 0;
139+
entry = ref Unsafe.Add(ref entry, 1);
155140
}
156141
}
157142
}

‎src/LibObjectFile/Elf/Sections/ElfSymbol.cs

+1-1
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@ namespace LibObjectFile.Elf;
1010
/// A symbol entry in the <see cref="ElfSymbolTable"/>
1111
/// This is the value seen in <see cref="ElfNative.Elf32_Sym"/> or <see cref="ElfNative.Elf64_Sym"/>
1212
/// </summary>
13-
public record ElfSymbol
13+
public record struct ElfSymbol
1414
{
1515
/// <summary>
1616
/// Gets or sets the value associated to this symbol.

‎src/LibObjectFile/Elf/Sections/ElfSymbolTable.cs

+24-30
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,10 @@
44

55
using System;
66
using System.Collections.Generic;
7+
using System.Runtime.CompilerServices;
8+
using System.Runtime.InteropServices;
79
using LibObjectFile.Diagnostics;
10+
using LibObjectFile.IO;
811

912
namespace LibObjectFile.Elf;
1013

@@ -36,13 +39,17 @@ public override void Read(ElfReader reader)
3639
reader.Position = Position;
3740
Entries.Clear();
3841

42+
var numberOfEntries = (int)(base.Size / base.TableEntrySize);
43+
var entries = Entries;
44+
CollectionsMarshal.SetCount(entries, numberOfEntries);
45+
3946
if (_is32)
4047
{
41-
Read32(reader);
48+
Read32(reader, numberOfEntries);
4249
}
4350
else
4451
{
45-
Read64(reader);
52+
Read64(reader, numberOfEntries);
4653
}
4754
}
4855

@@ -58,20 +65,15 @@ public override void Write(ElfWriter writer)
5865
}
5966
}
6067

61-
private void Read32(ElfReader reader)
68+
private void Read32(ElfReader reader, int numberOfEntries)
6269
{
63-
var numberOfEntries = base.Size / base.TableEntrySize;
64-
Entries.Capacity = (int)numberOfEntries;
65-
for (ulong i = 0; i < numberOfEntries; i++)
70+
using var batch = new BatchDataReader<ElfNative.Elf32_Sym>(reader.Stream, numberOfEntries);
71+
var span = CollectionsMarshal.AsSpan(Entries);
72+
ref var entry = ref MemoryMarshal.GetReference(span);
73+
while (batch.HasNext())
6674
{
67-
ElfNative.Elf32_Sym sym;
68-
ulong streamOffset = (ulong)reader.Stream.Position;
69-
if (!reader.TryReadData((int)base.TableEntrySize, out sym))
70-
{
71-
reader.Diagnostics.Error(DiagnosticId.ELF_ERR_IncompleteSymbolEntry32Size, $"Unable to read entirely the symbol entry [{i}] from {Type} section [{Index}]. Not enough data (size: {base.TableEntrySize}) read at offset {streamOffset} from the stream");
72-
}
75+
ref var sym = ref batch.ReadNext();
7376

74-
var entry = new ElfSymbol();
7577
entry.Name = new ElfString(reader.Decode(sym.st_name));
7678
entry.Value = reader.Decode(sym.st_value);
7779
entry.Size = reader.Decode(sym.st_size);
@@ -81,25 +83,19 @@ private void Read32(ElfReader reader)
8183
entry.Bind = (ElfSymbolBind)(st_info >> 4);
8284
entry.Visibility = (ElfSymbolVisibility) sym.st_other;
8385
entry.SectionLink = new ElfSectionLink(reader.Decode(sym.st_shndx));
84-
85-
Entries.Add(entry);
86+
entry = ref Unsafe.Add(ref entry, 1);
8687
}
8788
}
8889

89-
private void Read64(ElfReader reader)
90+
private void Read64(ElfReader reader, int numberOfEntries)
9091
{
91-
var numberOfEntries = base.Size / base.TableEntrySize;
92-
Entries.Capacity = (int)numberOfEntries;
93-
for (ulong i = 0; i < numberOfEntries; i++)
92+
using var batch = new BatchDataReader<ElfNative.Elf64_Sym>(reader.Stream, numberOfEntries);
93+
var span = CollectionsMarshal.AsSpan(Entries);
94+
ref var entry = ref MemoryMarshal.GetReference(span);
95+
while (batch.HasNext())
9496
{
95-
ElfNative.Elf64_Sym sym;
96-
ulong streamOffset = (ulong)reader.Stream.Position;
97-
if (!reader.TryReadData((int)base.TableEntrySize, out sym))
98-
{
99-
reader.Diagnostics.Error(DiagnosticId.ELF_ERR_IncompleteSymbolEntry64Size, $"Unable to read entirely the symbol entry [{i}] from {Type} section [{Index}]. Not enough data (size: {base.TableEntrySize}) read at offset {streamOffset} from the stream");
100-
}
97+
ref var sym = ref batch.ReadNext();
10198

102-
var entry = new ElfSymbol();
10399
entry.Name = new ElfString(reader.Decode(sym.st_name));
104100
entry.Value = reader.Decode(sym.st_value);
105101
entry.Size = reader.Decode(sym.st_size);
@@ -109,12 +105,10 @@ private void Read64(ElfReader reader)
109105
entry.Bind = (ElfSymbolBind)(st_info >> 4);
110106
entry.Visibility = (ElfSymbolVisibility)sym.st_other;
111107
entry.SectionLink = new ElfSectionLink(reader.Decode(sym.st_shndx));
112-
113-
Entries.Add(entry);
108+
entry = ref Unsafe.Add(ref entry, 1);
114109
}
115110
}
116-
117-
111+
118112
private void Write32(ElfWriter writer)
119113
{
120114
var stringTable = (ElfStringTable)Link.Section!;

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