custom sections

Cargo.toml

@@ -23,6 +23,7 @@ addr2line = "0.19"
 # For fuzzing only. Versions must match those in fuzz/Cargo.toml.
 libfuzzer-sys = { version = "0.4", optional = true }
 wasm-smith = { version = "0.8", optional = true }
+indexmap = "2.2.2"
 
 [features]
 default = []

src/backend/mod.rs

@@ -7,6 +7,7 @@ use crate::Operator;
 use anyhow::Result;
 use rayon::prelude::*;
 use std::borrow::Cow;
+use wasm_encoder::CustomSection;
 
 pub mod stackify;
 use stackify::{Context as StackifyContext, WasmBlock};
@@ -787,6 +788,9 @@ pub fn compile(module: &Module<'_>) -> anyhow::Result<Vec<u8>> {
     }
     names.functions(&func_names);
     into_mod.section(&names);
+    for (k, v) in module.custom_sections.iter() {
+        into_mod.section(&CustomSection { name: &k, data: &v });
+    }
 
     Ok(into_mod.finish())
 }

src/frontend.rs

@@ -297,7 +297,11 @@ fn handle_payload<'a>(
             extra_sections.debug_rnglists =
                 gimli::DebugRngLists::new(reader.data(), gimli::LittleEndian);
         }
-        Payload::CustomSection(_) => {}
+        Payload::CustomSection(reader) => {
+            module
+                .custom_sections
+                .insert(reader.name().to_owned(), reader.data().to_owned());
+        }
         Payload::Version { .. } => {}
         Payload::ElementSection(reader) => {
             for element in reader {

src/ir/module.rs

@@ -3,6 +3,7 @@ use crate::entity::{EntityRef, EntityVec};
 use crate::ir::{Debug, DebugMap, FunctionBody};
 use crate::{backend, frontend};
 use anyhow::Result;
+use indexmap::IndexMap;
 
 pub use crate::frontend::FrontendOptions;
 
@@ -19,6 +20,7 @@ pub struct Module<'a> {
     pub start_func: Option<Func>,
     pub debug: Debug,
     pub debug_map: DebugMap,
+    pub custom_sections: IndexMap<String,Vec<u8>>
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -143,6 +145,7 @@ impl<'a> Module<'a> {
             start_func: None,
             debug: Debug::default(),
             debug_map: DebugMap::default(),
+            custom_sections: IndexMap::new(),
         }
     }
 
@@ -165,6 +168,7 @@ impl<'a> Module<'a> {
             start_func: self.start_func,
             debug: self.debug,
             debug_map: self.debug_map,
+            custom_sections: self.custom_sections,
         }
     }
 }