From 474809f5f3a4dd4975c5ff620ff1ab6af5adeac6 Mon Sep 17 00:00:00 2001
From: Yury Delendik <ydelendik@mozilla.com>
Date: Tue, 2 Apr 2019 16:30:30 -0500
Subject: [PATCH] Support imports in wasm2obj

---
 wasmtime-obj/src/function.rs | 37 +++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/wasmtime-obj/src/function.rs b/wasmtime-obj/src/function.rs
index 246c5d6459..49bd57ce65 100644
--- a/wasmtime-obj/src/function.rs
+++ b/wasmtime-obj/src/function.rs
@@ -4,12 +4,36 @@ use cranelift_entity::EntityRef;
 use faerie::{Artifact, Decl, Link};
 use wasmtime_environ::{Compilation, Module, RelocationTarget, Relocations};
 
+fn get_reloc_target_special_import_name(target: RelocationTarget) -> Option<&'static str> {
+    Some(match target {
+        RelocationTarget::Memory32Grow => &"wasmtime_memory32_grow",
+        RelocationTarget::ImportedMemory32Grow => &"wasmtime_memory32_grow",
+        RelocationTarget::Memory32Size => &"wasmtime_memory32_size",
+        RelocationTarget::ImportedMemory32Size => &"wasmtime_imported_memory32_size",
+        _ => return None,
+    })
+}
+
 /// Defines module functions
 pub fn declare_functions(
     obj: &mut Artifact,
     module: &Module,
     relocations: &Relocations,
 ) -> Result<(), String> {
+    for i in 0..module.imported_funcs.len() {
+        let string_name = format!("_wasm_function_{}", i);
+        obj.declare(string_name, Decl::function_import())
+            .map_err(|err| format!("{}", err))?;
+    }
+    for (_, function_relocs) in relocations.iter() {
+        for r in function_relocs {
+            let special_import_name = get_reloc_target_special_import_name(r.reloc_target);
+            if let Some(special_import_name) = special_import_name {
+                obj.declare(special_import_name, Decl::function_import())
+                    .map_err(|err| format!("{}", err))?;
+            }
+        }
+    }
     for (i, _function_relocs) in relocations.iter().rev() {
         let func_index = module.func_index(i);
         let string_name = format!("_wasm_function_{}", func_index.index());
@@ -61,7 +85,18 @@ pub fn emit_functions(
                     })
                     .map_err(|err| format!("{}", err))?;
                 }
-                _ => panic!("relocations target not supported yet"),
+                RelocationTarget::Memory32Grow
+                | RelocationTarget::ImportedMemory32Grow
+                | RelocationTarget::Memory32Size
+                | RelocationTarget::ImportedMemory32Size => {
+                    obj.link(Link {
+                        from: &string_name,
+                        to: get_reloc_target_special_import_name(r.reloc_target).expect("name"),
+                        at: r.offset as u64,
+                    })
+                    .map_err(|err| format!("{}", err))?;
+                }
+                _ => panic!("relocations target not supported yet: {:?}", r.reloc_target),
             };
         }
     }