self review

compiler/gen_wasm/src/backend.rs

@@ -395,14 +395,18 @@ impl<'a> WasmBackend<'a> {
 
                     self.storage.load_symbols(&mut self.code_builder, wasm_args);
 
-                    // Index of the called function in the Wasm module code section
+                    // Index of the called function in the code section
-                    // TODO: update when we start inlining functions (remember we emit procs out of order)
+                    // TODO: account for inlined functions when we start doing that (remember we emit procs out of order)
-                    let func_index = self
+                    let func_index = match self.proc_symbols.iter().position(|s| s == func_sym) {
-                        .proc_symbols
+                        Some(i) => i as u32,
-                        .iter()
+                        None => {
-                        .position(|s| s == func_sym)
+                            // TODO: actually useful linking! Push a relocation for it.
-                        .map(|i| i as u32)
+                            return Err(format!(
-                        .unwrap_or(u32::MAX); // foreign symbol, updated at link time
+                                "Not yet supporteed: calling foreign function {:?}",
+                                func_sym
+                            ));
+                        }
+                    };
 
                     // Index of the function's name in the symbol table
                     let symbol_index = func_index; // TODO: update this when we add other things to the symbol table

compiler/gen_wasm/src/code_builder.rs

@@ -141,8 +141,8 @@ pub struct CodeBuilder<'a> {
     /// Keeps track of where Symbol values are in the VM stack
     vm_stack: Vec<'a, Symbol>,
 
-    /// Which byte offsets in the code section correspond to which symbols.
+    /// Linker info to help combine the Roc module with builtin & platform modules,
-    /// e.g. Function indices may change when we link Roc + builtins + platform
+    /// e.g. to modify call instructions when function indices change
     relocations: Vec<'a, RelocationEntry>,
 }
 

compiler/gen_wasm/tests/helpers/wasm32_test_result.rs

@@ -12,7 +12,7 @@ pub trait Wasm32TestResult {
         module_builder: &mut builder::ModuleBuilder,
         code_section_bytes: &mut std::vec::Vec<u8>,
         wrapper_name: &str,
-        main_fn_index: u32,
+        main_function_index: u32,
     ) {
         let signature = builder::signature()
             .with_result(parity_wasm::elements::ValueType::I32)
@@ -28,7 +28,7 @@ pub trait Wasm32TestResult {
         module_builder.push_export(export);
 
         let mut code_builder = CodeBuilder::new(arena);
-        Self::build_wrapper_body(&mut code_builder, main_fn_index);
+        Self::build_wrapper_body(&mut code_builder, main_function_index);
 
         code_builder.serialize(code_section_bytes);
 
@@ -41,12 +41,12 @@ pub trait Wasm32TestResult {
         code_section_bytes.overwrite_padded_u32(5, num_procs + 1);
     }
 
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32);
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32);
 }
 
 macro_rules! build_wrapper_body_primitive {
     ($store_instruction: ident, $align: expr) => {
-        fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+        fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
             let frame_pointer_id = LocalId(0);
             let frame_pointer = Some(frame_pointer_id);
             let local_types = &[ValueType::I32];
@@ -54,7 +54,7 @@ macro_rules! build_wrapper_body_primitive {
 
             code_builder.get_local(frame_pointer_id);
             // Raw "call" instruction. Don't bother with symbol & relocation since we're not going to link.
-            code_builder.inst_imm32(roc_gen_wasm::opcodes::CALL, 0, true, main_fn_index);
+            code_builder.inst_imm32(roc_gen_wasm::opcodes::CALL, 0, true, main_function_index);
             code_builder.$store_instruction($align, 0);
             code_builder.get_local(frame_pointer_id);
 
@@ -73,7 +73,7 @@ macro_rules! wasm_test_result_primitive {
 
 fn build_wrapper_body_stack_memory(
     code_builder: &mut CodeBuilder,
-    main_fn_index: u32,
+    main_function_index: u32,
     size: usize,
 ) {
     let local_id = LocalId(0);
@@ -82,7 +82,7 @@ fn build_wrapper_body_stack_memory(
 
     code_builder.get_local(local_id);
     // Raw "call" instruction. Don't bother with symbol & relocation since we're not going to link.
-    code_builder.inst_imm32(roc_gen_wasm::opcodes::CALL, 0, true, main_fn_index);
+    code_builder.inst_imm32(roc_gen_wasm::opcodes::CALL, 0, true, main_function_index);
     code_builder.get_local(local_id);
     code_builder.finalize(local_types, size as i32, frame_pointer);
 }
@@ -90,10 +90,10 @@ fn build_wrapper_body_stack_memory(
 macro_rules! wasm_test_result_stack_memory {
     ($type_name: ident) => {
         impl Wasm32TestResult for $type_name {
-            fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+            fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
                 build_wrapper_body_stack_memory(
                     code_builder,
-                    main_fn_index,
+                    main_function_index,
                     $type_name::ACTUAL_WIDTH,
                 )
             }
@@ -122,8 +122,8 @@ wasm_test_result_stack_memory!(RocDec);
 wasm_test_result_stack_memory!(RocStr);
 
 impl<T: Wasm32TestResult> Wasm32TestResult for RocList<T> {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
-        build_wrapper_body_stack_memory(code_builder, main_fn_index, 12)
+        build_wrapper_body_stack_memory(code_builder, main_function_index, 12)
     }
 }
 
@@ -135,8 +135,8 @@ impl<T, const N: usize> Wasm32TestResult for [T; N]
 where
     T: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
-        build_wrapper_body_stack_memory(code_builder, main_fn_index, N * T::ACTUAL_WIDTH)
+        build_wrapper_body_stack_memory(code_builder, main_function_index, N * T::ACTUAL_WIDTH)
     }
 }
 
@@ -145,10 +145,10 @@ where
     T: Wasm32TestResult + FromWasm32Memory,
     U: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
         build_wrapper_body_stack_memory(
             code_builder,
-            main_fn_index,
+            main_function_index,
             T::ACTUAL_WIDTH + U::ACTUAL_WIDTH,
         )
     }
@@ -160,10 +160,10 @@ where
     U: Wasm32TestResult + FromWasm32Memory,
     V: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
         build_wrapper_body_stack_memory(
             code_builder,
-            main_fn_index,
+            main_function_index,
             T::ACTUAL_WIDTH + U::ACTUAL_WIDTH + V::ACTUAL_WIDTH,
         )
     }
@@ -176,10 +176,10 @@ where
     V: Wasm32TestResult + FromWasm32Memory,
     W: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
         build_wrapper_body_stack_memory(
             code_builder,
-            main_fn_index,
+            main_function_index,
             T::ACTUAL_WIDTH + U::ACTUAL_WIDTH + V::ACTUAL_WIDTH + W::ACTUAL_WIDTH,
         )
     }
@@ -193,10 +193,10 @@ where
     W: Wasm32TestResult + FromWasm32Memory,
     X: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
         build_wrapper_body_stack_memory(
             code_builder,
-            main_fn_index,
+            main_function_index,
             T::ACTUAL_WIDTH + U::ACTUAL_WIDTH + V::ACTUAL_WIDTH + W::ACTUAL_WIDTH + X::ACTUAL_WIDTH,
         )
     }
@@ -211,10 +211,10 @@ where
     X: Wasm32TestResult + FromWasm32Memory,
     Y: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
         build_wrapper_body_stack_memory(
             code_builder,
-            main_fn_index,
+            main_function_index,
             T::ACTUAL_WIDTH
                 + U::ACTUAL_WIDTH
                 + V::ACTUAL_WIDTH
@@ -235,10 +235,10 @@ where
     Y: Wasm32TestResult + FromWasm32Memory,
     Z: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
         build_wrapper_body_stack_memory(
             code_builder,
-            main_fn_index,
+            main_function_index,
             T::ACTUAL_WIDTH
                 + U::ACTUAL_WIDTH
                 + V::ACTUAL_WIDTH
@@ -261,10 +261,10 @@ where
     Z: Wasm32TestResult + FromWasm32Memory,
     A: Wasm32TestResult + FromWasm32Memory,
 {
-    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_fn_index: u32) {
+    fn build_wrapper_body(code_builder: &mut CodeBuilder, main_function_index: u32) {
         build_wrapper_body_stack_memory(
             code_builder,
-            main_fn_index,
+            main_function_index,
             T::ACTUAL_WIDTH
                 + U::ACTUAL_WIDTH
                 + V::ACTUAL_WIDTH