Add support for the WASM_DYLINK_RUNTIME_PATH subsection of the dylink.0 custom section

crates/wasmparser/src/readers/core/dylink0.rs

@@ -12,6 +12,7 @@ const WASM_DYLINK_MEM_INFO: u8 = 1;
 const WASM_DYLINK_NEEDED: u8 = 2;
 const WASM_DYLINK_EXPORT_INFO: u8 = 3;
 const WASM_DYLINK_IMPORT_INFO: u8 = 4;
+const WASM_DYLINK_RUNTIME_PATH: u8 = 5;
 
 /// Represents a `WASM_DYLINK_MEM_INFO` field
 #[derive(Debug, Copy, Clone)]
@@ -56,6 +57,7 @@ pub enum Dylink0Subsection<'a> {
     Needed(Vec<&'a str>),
     ExportInfo(Vec<ExportInfo<'a>>),
     ImportInfo(Vec<ImportInfo<'a>>),
+    RuntimePath(Vec<&'a str>),
     Unknown {
         ty: u8,
         data: &'a [u8],
@@ -100,6 +102,11 @@ impl<'a> Subsection<'a> for Dylink0Subsection<'a> {
                     })
                     .collect::<Result<_, _>>()?,
             ),
+            WASM_DYLINK_RUNTIME_PATH => Self::RuntimePath(
+                (0..reader.read_var_u32()?)
+                    .map(|_| reader.read_string())
+                    .collect::<Result<_, _>>()?,
+            ),
             ty => Self::Unknown {
                 ty,
                 data,

crates/wasmprinter/src/lib.rs

@@ -2006,6 +2006,15 @@ impl Printer<'_, '_> {
                         self.end_group()?;
                     }
                 }
+                Dylink0Subsection::RuntimePath(runtime_path) => {
+                    self.newline(start)?;
+                    self.start_group("runtime-path")?;
+                    for s in runtime_path {
+                        self.result.write_str(" ")?;
+                        self.print_str(s)?;
+                    }
+                    self.end_group()?;
+                }
                 Dylink0Subsection::Unknown { ty, .. } => {
                     bail!("don't know how to print dylink.0 subsection id {ty}");
                 }

crates/wast/src/core/binary.rs

@@ -1392,6 +1392,7 @@ impl Encode for Dylink0Subsection<'_> {
             Dylink0Subsection::Needed(libs) => libs.encode(e),
             Dylink0Subsection::ExportInfo(list) => list.encode(e),
             Dylink0Subsection::ImportInfo(list) => list.encode(e),
+            Dylink0Subsection::RuntimePath(list) => list.encode(e),
         }
     }
 }

crates/wast/src/core/custom.rs

@@ -261,6 +261,7 @@ pub enum Dylink0Subsection<'a> {
     Needed(Vec<&'a str>),
     ExportInfo(Vec<(&'a str, u32)>),
     ImportInfo(Vec<(&'a str, &'a str, u32)>),
+    RuntimePath(Vec<&'a str>),
 }
 
 impl<'a> Parse<'a> for Dylink0<'a> {
@@ -335,6 +336,13 @@ impl<'a> Dylink0<'a> {
                     .subsections
                     .push(Dylink0Subsection::ImportInfo(vec![(module, name, flags)])),
             }
+        } else if l.peek::<kw::runtime_path>()? {
+            parser.parse::<kw::runtime_path>()?;
+            let mut names = Vec::new();
+            while !parser.is_empty() {
+                names.push(parser.parse()?);
+            }
+            self.subsections.push(Dylink0Subsection::RuntimePath(names));
         } else {
             return Err(l.error());
         }
@@ -388,6 +396,7 @@ impl Dylink0Subsection<'_> {
             Needed(..) => 2,
             ExportInfo(..) => 3,
             ImportInfo(..) => 4,
+            RuntimePath(..) => 5,
         }
     }
 }

crates/wast/src/lib.rs

@@ -555,6 +555,7 @@ pub mod kw {
     custom_keyword!(needed);
     custom_keyword!(export_info = "export-info");
     custom_keyword!(import_info = "import-info");
+    custom_keyword!(runtime_path = "runtime-path");
     custom_keyword!(thread);
     custom_keyword!(thread_spawn_ref = "thread.spawn_ref");
     custom_keyword!(thread_spawn_indirect = "thread.spawn_indirect");

crates/wit-component/src/linking/metadata.rs

@@ -169,6 +169,9 @@ pub struct Metadata<'a> {
     /// The `WASM_DYLINK_NEEDED` values, if any
     pub needed_libs: Vec<&'a str>,
 
+    /// The `WASM_DYLINK_RUNTIME_PATH` values, if any
+    pub runtime_path: Vec<&'a str>,
+
     /// Whether this module exports `__wasm_apply_data_relocs`
     pub has_data_relocs: bool,
 
@@ -228,6 +231,7 @@ impl<'a> Metadata<'a> {
                 table_alignment: 1,
             },
             needed_libs: Vec::new(),
+            runtime_path: Vec::new(),
             has_data_relocs: false,
             has_ctors: false,
             has_initialize: false,
@@ -267,6 +271,9 @@ impl<'a> Metadata<'a> {
                                             .map(|info| ((info.module, info.field), info.flags)),
                                     );
                                 }
+                                Dylink0Subsection::RuntimePath(runtime_path) => {
+                                    result.runtime_path.extend(runtime_path.iter());
+                                }
                                 Dylink0Subsection::Unknown { ty, .. } => {
                                     bail!("unrecognized `dylink.0` subsection: {ty}")
                                 }

tests/cli/dump-dylink0.wat

@@ -7,5 +7,6 @@
     (export-info "a" 0)
     (import-info "a" "a" 0)
     (export-info "a" 2 binding-local binding-weak 0 undefined)
+    (runtime-path "a" "b")
   )
 )

tests/cli/dump-dylink0.wat.stdout

@@ -1,6 +1,6 @@
   0x0 | 00 61 73 6d | version 1 (Module)
       | 01 00 00 00
-  0x8 | 00 2a       | custom section
+  0x8 | 00 31       | custom section
   0xa | 08 64 79 6c | name: "dylink.0"
       | 69 6e 6b 2e
       | 30         
@@ -13,4 +13,6 @@
  0x26 | 04 06 01 01 | ImportInfo([ImportInfo { module: "a", field: "a", flags: SymbolFlags(0x0) }])
       | 61 01 61 00
  0x2e | 03 04 01 01 | ExportInfo([ExportInfo { name: "a", flags: SymbolFlags(BINDING_WEAK | BINDING_LOCAL | UNDEFINED) }])
-      | 61 13
+      | 61 13      
+ 0x34 | 05 05 02 01 | RuntimePath(["a", "b"])
+      | 61 01 62

tests/cli/dylink0.wast

@@ -47,6 +47,7 @@
     (export-info "a" 0)
     (import-info "a" "a" 0)
     (import-info "b" "b" 1)
+    (runtime-path "a" "b")
   )
 )
 

tests/snapshots/cli/dylink0.wast.json

@@ -45,13 +45,13 @@
     },
     {
       "type": "module",
-      "line": 53,
+      "line": 54,
       "filename": "dylink0.7.wasm",
       "module_type": "binary"
     },
     {
       "type": "module",
-      "line": 66,
+      "line": 67,
       "filename": "dylink0.8.wasm",
       "module_type": "binary"
     }

tests/snapshots/cli/dylink0.wast/6.print

@@ -5,5 +5,6 @@
     (export-info "a")
     (import-info "a" "a")
     (import-info "b" "b" binding-weak)
+    (runtime-path "a" "b")
   )
 )