[wasmtime-api] Access to/override module name

crates/api/src/instance.rs

@@ -29,6 +29,7 @@ impl Resolver for SimpleResolver {
 pub fn instantiate_in_context(
     data: &[u8],
     imports: Vec<(String, String, Extern)>,
+    module_name: Option<String>,
     context: Context,
     exports: Rc<RefCell<HashMap<String, Option<wasmtime_runtime::Export>>>>,
 ) -> Result<(InstanceHandle, HashSet<Context>), Error> {
@@ -38,6 +39,7 @@ pub fn instantiate_in_context(
     let instance = instantiate(
         &mut context.compiler(),
         data,
+        module_name,
         &mut resolver,
         exports,
         debug_info,
@@ -77,8 +79,13 @@ impl Instance {
             .zip(externs.iter())
             .map(|(i, e)| (i.module().to_string(), i.name().to_string(), e.clone()))
             .collect::<Vec<_>>();
-        let (mut instance_handle, contexts) =
-            instantiate_in_context(module.binary().expect("binary"), imports, context, exports)?;
+        let (mut instance_handle, contexts) = instantiate_in_context(
+            module.binary().expect("binary"),
+            imports,
+            module.name().cloned(),
+            context,
+            exports,
+        )?;
 
         let exports = {
             let mut exports = Vec::with_capacity(module.exports().len());

crates/api/src/module.rs

@@ -6,8 +6,8 @@ use crate::types::{
 use anyhow::{Error, Result};
 use std::rc::Rc;
 use wasmparser::{
-    validate, ExternalKind, ImportSectionEntryType, ModuleReader, OperatorValidatorConfig,
-    SectionCode, ValidatingParserConfig,
+    validate, CustomSectionKind, ExternalKind, ImportSectionEntryType, ModuleReader, Name,
+    OperatorValidatorConfig, SectionCode, ValidatingParserConfig,
 };
 
 fn into_memory_type(mt: wasmparser::MemoryType) -> MemoryType {
@@ -56,7 +56,9 @@ fn into_table_type(tt: wasmparser::TableType) -> TableType {
     TableType::new(ty, limits)
 }
 
-fn read_imports_and_exports(binary: &[u8]) -> Result<(Box<[ImportType]>, Box<[ExportType]>)> {
+fn read_imports_and_exports(
+    binary: &[u8],
+) -> Result<(Box<[ImportType]>, Box<[ExportType]>, Option<String>)> {
     let mut reader = ModuleReader::new(binary)?;
     let mut imports = Vec::new();
     let mut exports = Vec::new();
@@ -65,6 +67,7 @@ fn read_imports_and_exports(binary: &[u8]) -> Result<(Box<[ImportType]>, Box<[Ex
     let mut func_sig = Vec::new();
     let mut sigs = Vec::new();
     let mut globals = Vec::new();
+    let mut module_name = None;
     while !reader.eof() {
         let section = reader.read()?;
         match section.code {
@@ -157,12 +160,32 @@ fn read_imports_and_exports(binary: &[u8]) -> Result<(Box<[ImportType]>, Box<[Ex
                     exports.push(ExportType::new(entry.field, r#type));
                 }
             }
+            SectionCode::Custom {
+                kind: CustomSectionKind::Name,
+                ..
+            } => {
+                // Read name section. Per spec, ignore invalid custom section.
+                if let Ok(mut reader) = section.get_name_section_reader() {
+                    while let Ok(entry) = reader.read() {
+                        if let Name::Module(name) = entry {
+                            if let Ok(name) = name.get_name() {
+                                module_name = Some(name.to_string());
+                            }
+                            break;
+                        }
+                    }
+                }
+            }
             _ => {
                 // skip other sections
             }
         }
     }
-    Ok((imports.into_boxed_slice(), exports.into_boxed_slice()))
+    Ok((
+        imports.into_boxed_slice(),
+        exports.into_boxed_slice(),
+        module_name,
+    ))
 }
 
 #[derive(Clone)]
@@ -196,6 +219,7 @@ struct ModuleInner {
     source: ModuleCodeSource,
     imports: Box<[ImportType]>,
     exports: Box<[ExportType]>,
+    name: Option<String>,
 }
 
 impl Module {
@@ -239,7 +263,16 @@ impl Module {
         // Note that the call to `unsafe` here should be ok because we
         // previously validated the binary, meaning we're guaranteed to pass a
         // valid binary for `store`.
-        unsafe { Self::new_unchecked(store, binary) }
+        unsafe { Self::create(store, binary, None) }
+    }
+
+    /// Creates a new WebAssembly `Module` from the given in-memory `binary`
+    /// data. The provided `name` will be used in traps/backtrace details.
+    ///
+    /// See [`Module::new`] for other details.
+    pub fn new_with_name(store: &Store, binary: &[u8], name: String) -> Result<Module> {
+        Self::validate(store, binary)?;
+        unsafe { Self::create(store, binary, Some(name)) }
     }
 
     /// Creates a new WebAssembly `Module` from the given in-memory `binary`
@@ -269,13 +302,22 @@ impl Module {
     /// be somewhat valid for decoding purposes, and the basics of decoding can
     /// still fail.
     pub unsafe fn new_unchecked(store: &Store, binary: &[u8]) -> Result<Module> {
-        let (imports, exports) = read_imports_and_exports(binary)?;
+        Self::create(store, binary, None)
+    }
+
+    unsafe fn create(
+        store: &Store,
+        binary: &[u8],
+        name_override: Option<String>,
+    ) -> Result<Module> {
+        let (imports, exports, name) = read_imports_and_exports(binary)?;
         Ok(Module {
             inner: Rc::new(ModuleInner {
                 store: store.clone(),
                 source: ModuleCodeSource::Binary(binary.into()),
                 imports,
                 exports,
+                name: name_override.or(name),
             }),
         })
     }
@@ -320,6 +362,7 @@ impl Module {
                 source: ModuleCodeSource::Unknown,
                 imports: Box::new([]),
                 exports,
+                name: None,
             }),
         }
     }
@@ -331,6 +374,12 @@ impl Module {
         }
     }
 
+    /// Returns identifier/name that this [`Module`] has. This name
+    /// is used in traps/backtrace details.
+    pub fn name(&self) -> Option<&String> {
+        self.inner.name.as_ref()
+    }
+
     /// Returns the list of imports that this [`Module`] has and must be
     /// satisfied.
     pub fn imports(&self) -> &[ImportType] {

crates/api/tests/name.rs

@@ -0,0 +1,54 @@
+use wasmtime::*;
+use wat::parse_str;
+
+#[test]
+fn test_module_no_name() -> Result<(), String> {
+    let store = Store::default();
+    let binary = parse_str(
+        r#"
+                (module
+                (func (export "run") (nop))
+                )
+            "#,
+    )
+    .map_err(|e| format!("failed to parse WebAssembly text source: {}", e))?;
+
+    let module = HostRef::new(
+        Module::new(&store, &binary).map_err(|e| format!("failed to compile module: {}", e))?,
+    );
+    assert_eq!(module.borrow().name().cloned(), None);
+
+    Ok(())
+}
+
+#[test]
+fn test_module_name() -> Result<(), String> {
+    let store = Store::default();
+    let binary = parse_str(
+        r#"
+                (module $from_name_section
+                (func (export "run") (nop))
+                )
+            "#,
+    )
+    .map_err(|e| format!("failed to parse WebAssembly text source: {}", e))?;
+
+    let module = HostRef::new(
+        Module::new(&store, &binary).map_err(|e| format!("failed to compile module: {}", e))?,
+    );
+    assert_eq!(
+        module.borrow().name().cloned(),
+        Some("from_name_section".to_string())
+    );
+
+    let module = HostRef::new(
+        Module::new_with_name(&store, &binary, "override".to_string())
+            .map_err(|e| format!("failed to compile module: {}", e))?,
+    );
+    assert_eq!(
+        module.borrow().name().cloned(),
+        Some("override".to_string())
+    );
+
+    Ok(())
+}

crates/environ/src/module.rs

@@ -168,6 +168,9 @@ pub struct Module {
 
     /// WebAssembly table initializers.
     pub table_elements: Vec<TableElements>,
+
+    /// Module name.
+    pub name: Option<String>,
 }
 
 impl Module {
@@ -186,6 +189,7 @@ impl Module {
             exports: IndexMap::new(),
             start_func: None,
             table_elements: Vec::new(),
+            name: None,
         }
     }
 

crates/fuzzing/src/oracles.rs

@@ -78,7 +78,14 @@ pub fn compile(wasm: &[u8], compilation_strategy: CompilationStrategy) {
     let mut compiler = Compiler::new(isa, compilation_strategy);
     let mut resolver = NullResolver {};
     let global_exports = Rc::new(RefCell::new(HashMap::new()));
-    let _ = CompiledModule::new(&mut compiler, wasm, &mut resolver, global_exports, false);
+    let _ = CompiledModule::new(
+        &mut compiler,
+        wasm,
+        None,
+        &mut resolver,
+        global_exports,
+        false,
+    );
 }
 
 /// Invoke the given API calls.

crates/jit/src/context.rs

@@ -117,6 +117,7 @@ impl Context {
         instantiate(
             &mut *self.compiler,
             &data,
+            None,
             &mut self.namespace,
             Rc::clone(&self.global_exports),
             debug_info,
@@ -154,6 +155,7 @@ impl Context {
         CompiledModule::new(
             &mut *self.compiler,
             data,
+            None,
             &mut self.namespace,
             Rc::clone(&self.global_exports),
             debug_info,

crates/jit/src/instantiate.rs

@@ -60,12 +60,13 @@ impl<'data> RawCompiledModule<'data> {
     fn new(
         compiler: &mut Compiler,
         data: &'data [u8],
+        module_name: Option<String>,
         resolver: &mut dyn Resolver,
         debug_info: bool,
     ) -> Result<Self, SetupError> {
         let environ = ModuleEnvironment::new(compiler.frontend_config(), compiler.tunables());
 
-        let translation = environ
+        let mut translation = environ
             .translate(data)
             .map_err(|error| SetupError::Compile(CompileError::Wasm(error)))?;
 
@@ -75,6 +76,8 @@ impl<'data> RawCompiledModule<'data> {
             None
         };
 
+        translation.module.name = module_name;
+
         let (allocated_functions, jt_offsets, relocations, dbg_image) = compiler.compile(
             &translation.module,
             translation.module_translation.as_ref().unwrap(),
@@ -152,11 +155,13 @@ impl CompiledModule {
     pub fn new<'data>(
         compiler: &mut Compiler,
         data: &'data [u8],
+        module_name: Option<String>,
         resolver: &mut dyn Resolver,
         global_exports: Rc<RefCell<HashMap<String, Option<Export>>>>,
         debug_info: bool,
     ) -> Result<Self, SetupError> {
-        let raw = RawCompiledModule::<'data>::new(compiler, data, resolver, debug_info)?;
+        let raw =
+            RawCompiledModule::<'data>::new(compiler, data, module_name, resolver, debug_info)?;
 
         Ok(Self::from_parts(
             raw.module,
@@ -258,11 +263,12 @@ impl OwnedDataInitializer {
 pub fn instantiate(
     compiler: &mut Compiler,
     data: &[u8],
+    module_name: Option<String>,
     resolver: &mut dyn Resolver,
     global_exports: Rc<RefCell<HashMap<String, Option<Export>>>>,
     debug_info: bool,
 ) -> Result<InstanceHandle, SetupError> {
-    let raw = RawCompiledModule::new(compiler, data, resolver, debug_info)?;
+    let raw = RawCompiledModule::new(compiler, data, module_name, resolver, debug_info)?;
 
     InstanceHandle::new(
         Rc::new(raw.module),

tests/instantiate.rs

@@ -25,6 +25,13 @@ fn test_environ_translate() {
     let mut resolver = NullResolver {};
     let mut compiler = Compiler::new(isa, CompilationStrategy::Auto);
     let global_exports = Rc::new(RefCell::new(HashMap::new()));
-    let instance = instantiate(&mut compiler, &data, &mut resolver, global_exports, false);
+    let instance = instantiate(
+        &mut compiler,
+        &data,
+        None,
+        &mut resolver,
+        global_exports,
+        false,
+    );
     assert!(instance.is_ok());
 }