From 1482648219ab1cd6a0f8e9ce1e1657effa3d8cd3 Mon Sep 17 00:00:00 2001
From: Syrus Akbary <me@syrusakbary.com>
Date: Mon, 15 Oct 2018 13:45:44 +0200
Subject: [PATCH] Added module.info.exports for O(1) retrieval

---
 src/webassembly/instance.rs | 10 +++++---
 src/webassembly/mod.rs      |  2 +-
 src/webassembly/module.rs   | 47 +++++++++++++++++++++++++++++++++----
 3 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/src/webassembly/instance.rs b/src/webassembly/instance.rs
index a1e89ea8f..0e60d1da1 100644
--- a/src/webassembly/instance.rs
+++ b/src/webassembly/instance.rs
@@ -97,8 +97,12 @@ impl Instance {
             // Compile the functions (from cranelift IR to machine code)
             for function_body in module.info.function_bodies.values() {
                 let mut func_context = Context::for_function(function_body.to_owned());
-                func_context.verify(&*isa).map_err(|e| ErrorKind::CompileError(e.to_string()))?;
-                func_context.verify_locations(&*isa).map_err(|e| ErrorKind::CompileError(e.to_string()))?;
+                func_context
+                    .verify(&*isa)
+                    .map_err(|e| ErrorKind::CompileError(e.to_string()))?;
+                func_context
+                    .verify_locations(&*isa)
+                    .map_err(|e| ErrorKind::CompileError(e.to_string()))?;
                 let code_size_offset = func_context
                     .compile(&*isa)
                     .map_err(|e| ErrorKind::CompileError(e.to_string()))?
@@ -223,7 +227,7 @@ impl Instance {
     pub fn memories(&self) -> Arc<Vec<LinearMemory>> {
         self.memories.clone()
     }
-    
+
     /// Invoke a WebAssembly function given a FuncIndex and the
     /// arguments that the function should be called with
     pub fn invoke(&self, func_index: FuncIndex, args: Vec<i32>) {
diff --git a/src/webassembly/mod.rs b/src/webassembly/mod.rs
index 14dd6f4e1..3924b299d 100644
--- a/src/webassembly/mod.rs
+++ b/src/webassembly/mod.rs
@@ -16,7 +16,7 @@ use wasmparser;
 pub use self::errors::{Error, ErrorKind};
 pub use self::instance::Instance;
 pub use self::memory::LinearMemory;
-pub use self::module::Module;
+pub use self::module::{Export, Module, ModuleInfo};
 
 pub struct ResultObject {
     /// A webassembly::Module object representing the compiled WebAssembly module.
diff --git a/src/webassembly/module.rs b/src/webassembly/module.rs
index fa4d2fcb0..8182353a5 100644
--- a/src/webassembly/module.rs
+++ b/src/webassembly/module.rs
@@ -1,5 +1,9 @@
 //! "" implementations of `ModuleEnvironment` and `FuncEnvironment` for testing
 //! wasm translation.
+use std::collections::HashMap;
+use std::string::String;
+use std::vec::Vec;
+use target_lexicon::{PointerWidth, Triple};
 
 use cranelift_codegen::cursor::FuncCursor;
 use cranelift_codegen::ir::immediates::{Imm64, Offset32};
@@ -12,8 +16,6 @@ use cranelift_codegen::print_errors::pretty_verifier_error;
 use cranelift_codegen::{isa, settings, verifier};
 use cranelift_entity::{EntityRef, PrimaryMap};
 
-use super::errors::ErrorKind;
-use super::memory::LinearMemory;
 use cranelift_wasm::{
     translate_module, // ReturnMode,
     DefinedFuncIndex,
@@ -31,9 +33,9 @@ use cranelift_wasm::{
     TableIndex,
     WasmResult,
 };
-use std::string::String;
-use std::vec::Vec;
-use target_lexicon::{PointerWidth, Triple};
+
+use super::errors::ErrorKind;
+use super::memory::LinearMemory;
 
 /// Compute a `ir::ExternalName` for a given wasm function index.
 fn get_func_name(func_index: FuncIndex) -> ir::ExternalName {
@@ -58,6 +60,19 @@ impl<T> Exportable<T> {
     }
 }
 
+/// An entity to export.
+#[derive(Clone, Debug)]
+pub enum Export {
+    /// Function export.
+    Function(FuncIndex),
+    /// Table export.
+    Table(TableIndex),
+    /// Memory export.
+    Memory(MemoryIndex),
+    /// Global export.
+    Global(GlobalIndex),
+}
+
 /// The main state belonging to a `Module`. This is split out from
 /// `Module` to allow it to be borrowed separately from the
 /// `FuncTranslator` field.
@@ -107,6 +122,11 @@ pub struct ModuleInfo {
 
     /// The data initializers
     pub data_initializers: Vec<DataInitializer>,
+
+    /// Exported entities
+    /// We use this in order to have a O(1) allocation of the exports
+    /// rather than iterating through the Exportable elements.
+    pub exports: HashMap<String, Export>,
 }
 
 impl ModuleInfo {
@@ -129,6 +149,7 @@ impl ModuleInfo {
             data_initializers: Vec::new(),
             main_memory_base: None,
             memory_base: None,
+            exports: HashMap::new(),
         }
     }
 }
@@ -668,24 +689,40 @@ impl<'data> ModuleEnvironment<'data> for Module {
         self.info.functions[func_index]
             .export_names
             .push(String::from(name));
+        // We add to the exports to have O(1) retrieval
+        self.info
+            .exports
+            .insert(name.to_string(), Export::Function(func_index));
     }
 
     fn declare_table_export(&mut self, table_index: TableIndex, name: &'data str) {
         self.info.tables[table_index]
             .export_names
             .push(String::from(name));
+        // We add to the exports to have O(1) retrieval
+        self.info
+            .exports
+            .insert(name.to_string(), Export::Table(table_index));
     }
 
     fn declare_memory_export(&mut self, memory_index: MemoryIndex, name: &'data str) {
         self.info.memories[memory_index]
             .export_names
             .push(String::from(name));
+        // We add to the exports to have O(1) retrieval
+        self.info
+            .exports
+            .insert(name.to_string(), Export::Memory(memory_index));
     }
 
     fn declare_global_export(&mut self, global_index: GlobalIndex, name: &'data str) {
         self.info.globals[global_index]
             .export_names
             .push(String::from(name));
+        // We add to the exports to have O(1) retrieval
+        self.info
+            .exports
+            .insert(name.to_string(), Export::Global(global_index));
     }
 
     fn declare_start_func(&mut self, func_index: FuncIndex) {