1use crate::prelude::*;
2use crate::{BinaryReader, Result, Subsection, Subsections, SymbolFlags};
3use core::ops::Range;
4
5/// Parser for the dynamic linking `dylink.0` custom section.
6///
7/// This format is currently defined upstream at
8/// <https://github.com/WebAssembly/tool-conventions/blob/main/DynamicLinking.md>.
9pub type Dylink0SectionReader<'a> = Subsections<'a, Dylink0Subsection<'a>>;
10
11const WASM_DYLINK_MEM_INFO: u8 = 1;
12const WASM_DYLINK_NEEDED: u8 = 2;
13const WASM_DYLINK_EXPORT_INFO: u8 = 3;
14const WASM_DYLINK_IMPORT_INFO: u8 = 4;
15
16/// Represents a `WASM_DYLINK_MEM_INFO` field
17#[derive(Debug, Copy, Clone)]
18pub struct MemInfo {
19 /// Size of the memory area the loader should reserve for the module, which
20 /// will begin at `env.__memory_base`.
21 pub memory_size: u32,
22
23 /// The required alignment of the memory area, in bytes, encoded as a power
24 /// of 2.
25 pub memory_alignment: u32,
26
27 /// Size of the table area the loader should reserve for the module, which
28 /// will begin at `env.__table_base`.
29 pub table_size: u32,
30
31 /// The required alignment of the table area, in elements, encoded as a
32 /// power of 2.
33 pub table_alignment: u32,
34}
35
36#[allow(missing_docs)]
37#[derive(Debug)]
38pub struct ExportInfo<'a> {
39 pub name: &'a str,
40 pub flags: SymbolFlags,
41}
42
43#[allow(missing_docs)]
44#[derive(Debug)]
45pub struct ImportInfo<'a> {
46 pub module: &'a str,
47 pub field: &'a str,
48 pub flags: SymbolFlags,
49}
50
51/// Possible subsections of the `dylink.0` custom section.
52#[derive(Debug)]
53#[allow(missing_docs)]
54pub enum Dylink0Subsection<'a> {
55 MemInfo(MemInfo),
56 Needed(Vec<&'a str>),
57 ExportInfo(Vec<ExportInfo<'a>>),
58 ImportInfo(Vec<ImportInfo<'a>>),
59 Unknown {
60 ty: u8,
61 data: &'a [u8],
62 range: Range<usize>,
63 },
64}
65
66impl<'a> Subsection<'a> for Dylink0Subsection<'a> {
67 fn from_reader(id: u8, mut reader: BinaryReader<'a>) -> Result<Self> {
68 let data = reader.remaining_buffer();
69 let offset = reader.original_position();
70 Ok(match id {
71 WASM_DYLINK_MEM_INFO => Self::MemInfo(MemInfo {
72 memory_size: reader.read_var_u32()?,
73 memory_alignment: reader.read_var_u32()?,
74 table_size: reader.read_var_u32()?,
75 table_alignment: reader.read_var_u32()?,
76 }),
77 WASM_DYLINK_NEEDED => Self::Needed(
78 (0..reader.read_var_u32()?)
79 .map(|_| reader.read_string())
80 .collect::<Result<_, _>>()?,
81 ),
82 WASM_DYLINK_EXPORT_INFO => Self::ExportInfo(
83 (0..reader.read_var_u32()?)
84 .map(|_| {
85 Ok(ExportInfo {
86 name: reader.read_string()?,
87 flags: reader.read()?,
88 })
89 })
90 .collect::<Result<_, _>>()?,
91 ),
92 WASM_DYLINK_IMPORT_INFO => Self::ImportInfo(
93 (0..reader.read_var_u32()?)
94 .map(|_| {
95 Ok(ImportInfo {
96 module: reader.read_string()?,
97 field: reader.read_string()?,
98 flags: reader.read()?,
99 })
100 })
101 .collect::<Result<_, _>>()?,
102 ),
103 ty => Self::Unknown {
104 ty,
105 data,
106 range: offset..offset + data.len(),
107 },
108 })
109 }
110}
111