diff --git a/Cargo.lock b/Cargo.lock
index ec510bc05..5c55395df 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,3 +1,8 @@
+[[package]]
+name = "abort_on_panic"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "aho-corasick"
 version = "0.6.8"
@@ -53,6 +58,24 @@ dependencies = [
  "libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "bindgen"
+version = "0.31.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cexpr 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clang-sys 0.21.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "peeking_take_while 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "which 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.0.4"
@@ -73,11 +96,29 @@ name = "cc"
 version = "1.0.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "cexpr"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "nom 3.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "cfg-if"
 version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "clang-sys"
+version = "0.21.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "glob 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libloading 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "clap"
 version = "2.32.0"
@@ -253,6 +294,15 @@ name = "either"
 version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "env_logger"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "errno"
 version = "0.2.4"
@@ -355,6 +405,20 @@ name = "itoa"
 version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "kernel32-sys"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "lazy_static"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "lazy_static"
 version = "1.2.0"
@@ -370,6 +434,36 @@ name = "libc"
 version = "0.2.44"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "libffi"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "abort_on_panic 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libffi-sys 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "libffi-sys"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bindgen 0.31.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "make-cmd 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pkg-config 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "libloading"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "lock_api"
 version = "0.1.5"
@@ -379,6 +473,14 @@ dependencies = [
  "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "log"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "log"
 version = "0.4.5"
@@ -395,6 +497,19 @@ dependencies = [
  "libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "make-cmd"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "memchr"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "memchr"
 version = "2.1.0"
@@ -427,6 +542,14 @@ name = "nodrop"
 version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "nom"
+version = "3.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.6"
@@ -477,6 +600,16 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "peeking_take_while"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "pkg-config"
+version = "0.3.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "proc-macro2"
 version = "0.4.20"
@@ -485,6 +618,11 @@ dependencies = [
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "quote"
+version = "0.3.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "quote"
 version = "0.6.8"
@@ -612,6 +750,18 @@ dependencies = [
  "redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "regex"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aho-corasick 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "utf8-ranges 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "regex"
 version = "1.0.5"
@@ -624,6 +774,14 @@ dependencies = [
  "utf8-ranges 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "regex-syntax"
+version = "0.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ucd-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "regex-syntax"
 version = "0.6.2"
@@ -906,6 +1064,7 @@ dependencies = [
  "hashbrown 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "indicatif 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.44 (git+https://github.com/rust-lang/libc)",
+ "libffi 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "nix 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -930,6 +1089,19 @@ name = "wasmparser"
 version = "0.23.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "which"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "winapi"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "winapi"
 version = "0.3.6"
@@ -939,6 +1111,11 @@ dependencies = [
  "winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "winapi-build"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "winapi-i686-pc-windows-gnu"
 version = "0.4.0"
@@ -950,17 +1127,21 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
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+"checksum cexpr 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "42aac45e9567d97474a834efdee3081b3c942b2205be932092f53354ce503d6c"
 "checksum cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "0c4e7bb64a8ebb0d856483e1e682ea3422f883c5f5615a90d51a2c82fe87fdd3"
+"checksum clang-sys 0.21.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e414af9726e1d11660801e73ccc7fb81803fb5f49e5903a25b348b2b3b480d2e"
 "checksum clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b957d88f4b6a63b9d70d5f454ac8011819c6efa7727858f458ab71c756ce2d3e"
 "checksum clicolors-control 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "51872be694bb3bcbd1ea95c6dd467c2c46c6c64d287e1c9084ace7c3116ae9c0"
 "checksum cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
@@ -978,6 +1159,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2760899e32a1d58d5abb31129f8fae5de75220bc2176e77ff7c627ae45c918d9"
 "checksum docopt 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d60c92df70dfaaabecc14b409fd79f55ba0f247780529db1d73bfa601e1d3ac0"
 "checksum either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3be565ca5c557d7f59e7cfcf1844f9e3033650c929c6566f511e8005f205c1d0"
+"checksum env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3ddf21e73e016298f5cb37d6ef8e8da8e39f91f9ec8b0df44b7deb16a9f8cd5b"
 "checksum errno 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "c2a071601ed01b988f896ab14b95e67335d1eeb50190932a1320f7fe3cadc84e"
 "checksum errno-dragonfly 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "14ca354e36190500e1e1fb267c647932382b54053c50b14970856c0b00a35067"
 "checksum error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "07e791d3be96241c77c43846b665ef1384606da2cd2a48730abe606a12906e02"
@@ -991,23 +1173,35 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum hashbrown 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "64b7d419d0622ae02fe5da6b9a5e1964b610a65bb37923b976aeebb6dbb8f86e"
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 "checksum libc 0.2.44 (git+https://github.com/rust-lang/libc)" = "<none>"
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+"checksum peeking_take_while 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
+"checksum pkg-config 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)" = "676e8eb2b1b4c9043511a9b7bea0915320d7e502b0a079fb03f9635a5252b18c"
 "checksum proc-macro2 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)" = "3d7b7eaaa90b4a90a932a9ea6666c95a389e424eff347f0f793979289429feee"
+"checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
 "checksum quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)" = "dd636425967c33af890042c483632d33fa7a18f19ad1d7ea72e8998c6ef8dea5"
 "checksum rand 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8356f47b32624fef5b3301c1be97e5944ecdd595409cc5da11d05f211db6cfbd"
 "checksum rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ae9d223d52ae411a33cf7e54ec6034ec165df296ccd23533d671a28252b6f66a"
@@ -1022,7 +1216,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum rayon-core 1.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b055d1e92aba6877574d8fe604a63c8b5df60f60e5982bf7ccbb1338ea527356"
 "checksum redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "c214e91d3ecf43e9a4e41e578973adeb14b474f2bee858742d127af75a0112b1"
 "checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
+"checksum regex 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9329abc99e39129fcceabd24cf5d85b4671ef7c29c50e972bc5afe32438ec384"
 "checksum regex 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "2069749032ea3ec200ca51e4a31df41759190a88edca0d2d86ee8bedf7073341"
+"checksum regex-syntax 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7d707a4fa2637f2dca2ef9fd02225ec7661fe01a53623c1e6515b6916511f7a7"
 "checksum regex-syntax 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "747ba3b235651f6e2f67dfa8bcdcd073ddb7c243cb21c442fc12395dfcac212d"
 "checksum region 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3f9d3f2bb4b7085e6996e2765b56b783bd8f3a8a4ea5b95683063ca13cded993"
 "checksum remove_dir_all 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3488ba1b9a2084d38645c4c08276a1752dcbf2c7130d74f1569681ad5d2799c5"
@@ -1060,6 +1256,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum wabt-sys 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0cc8982bfe0a923f152e96d991e50a6f97fe73ca4af6d9d84d76634f03051fa2"
 "checksum wasmparser 0.22.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f46e666ecb4a406483a59a49f9d0c17f327e70da53a128eccddae2eadb95865c"
 "checksum wasmparser 0.23.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b5e01c420bc7d36e778bd242e1167b079562ba8b34087122cc9057187026d060"
+"checksum which 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e84a603e7e0b1ce1aa1ee2b109c7be00155ce52df5081590d1ffb93f4f515cb2"
+"checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "92c1eb33641e276cfa214a0522acad57be5c56b10cb348b3c5117db75f3ac4b0"
+"checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/Cargo.toml b/Cargo.toml
index 843c421c0..2f4c3f079 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -51,6 +51,7 @@ indicatif = "0.10"
 console = "0.7.1"
 field-offset = "0.1.1"
 hashbrown = "0.1"
+libffi = "0.6.4"
 
 [build-dependencies]
 wabt = "0.7.2"
diff --git a/src/recovery.rs b/src/recovery.rs
index efa0dc605..f1e4734ac 100644
--- a/src/recovery.rs
+++ b/src/recovery.rs
@@ -4,7 +4,9 @@
 //! are very special, the async signal unsafety of Rust's TLS implementation generally does not affect the correctness here
 //! unless you have memory unsafety elsewhere in your code.
 
+use crate::sighandler::install_sighandler;
 use nix::libc::siginfo_t;
+use nix::sys::signal::{Signal, SIGBUS, SIGFPE, SIGILL, SIGSEGV};
 use std::cell::{Cell, UnsafeCell};
 use std::sync::Once;
 
@@ -71,6 +73,37 @@ macro_rules! call_protected {
     };
 }
 
+pub fn call_protected<T>(f: impl FnOnce() -> T) -> Result<T, String> {
+    unsafe {
+        let jmp_buf = SETJMP_BUFFER.with(|buf| buf.get());
+        let prev_jmp_buf = *jmp_buf;
+
+        SIGHANDLER_INIT.call_once(|| {
+            install_sighandler();
+        });
+
+        let signum = setjmp(jmp_buf as *mut ::nix::libc::c_void);
+        if signum != 0 {
+            *jmp_buf = prev_jmp_buf;
+            let addr = CAUGHT_ADDRESS.with(|cell| cell.get());
+
+            let signal = match Signal::from_c_int(signum) {
+                Ok(SIGFPE) => "floating-point exception",
+                Ok(SIGILL) => "illegal instruction",
+                Ok(SIGSEGV) => "segmentation violation",
+                Ok(SIGBUS) => "bus error",
+                Err(_) => "error while getting the Signal",
+                _ => "unkown trapped signal",
+            };
+            Err(format!("trap at {:#x} - {}", addr, signal))
+        } else {
+            let ret = f(); // TODO: Switch stack?
+            *jmp_buf = prev_jmp_buf;
+            Ok(ret)
+        }
+    }
+}
+
 /// Unwinds to last protected_call.
 pub unsafe fn do_unwind(signum: i32, siginfo: *mut siginfo_t) -> ! {
     // Since do_unwind is only expected to get called from WebAssembly code which doesn't hold any host resources (locks etc.)
diff --git a/src/runtime/backend.rs b/src/runtime/backend.rs
index 87fd2d747..ba8ecf9c0 100644
--- a/src/runtime/backend.rs
+++ b/src/runtime/backend.rs
@@ -1,4 +1,4 @@
-use crate::runtime::{module::Module, types::FuncIndex, vm};
+use crate::runtime::{module::Module, vm};
 use std::ptr::NonNull;
 use std::sync::Arc;
 
@@ -7,5 +7,5 @@ pub trait Compiler {
 }
 
 pub trait FuncResolver {
-    fn resolve(&self, index: FuncIndex) -> Option<NonNull<vm::Func>>;
+    fn resolve(&self, module: &Module, name: &str) -> Option<NonNull<vm::Func>>;
 }
diff --git a/src/runtime/backing.rs b/src/runtime/backing.rs
index 966ad7bf7..fa612f3ee 100644
--- a/src/runtime/backing.rs
+++ b/src/runtime/backing.rs
@@ -1,7 +1,7 @@
 use crate::runtime::{
     instance::{Import, Imports},
     memory::LinearMemory,
-    module::Module,
+    module::{ImportName, Module},
     table::TableBacking,
     types::{GlobalInit, MapIndex, Val},
     vm,
@@ -216,7 +216,14 @@ impl ImportBacking {
         );
 
         let mut functions = Vec::with_capacity(module.imported_functions.len());
-        for (index, (mod_name, item_name)) in &module.imported_functions {
+        for (
+            index,
+            ImportName {
+                module: mod_name,
+                name: item_name,
+            },
+        ) in &module.imported_functions
+        {
             let expected_sig_index = module.signature_assoc[index];
             let expected_sig = &module.signatures[expected_sig_index];
             let import = imports.get(mod_name, item_name);
@@ -238,7 +245,17 @@ impl ImportBacking {
         }
 
         let mut globals = Vec::with_capacity(module.imported_globals.len());
-        for (_, ((mod_name, item_name), global_desc)) in &module.imported_globals {
+        for (
+            _,
+            (
+                ImportName {
+                    module: mod_name,
+                    name: item_name,
+                },
+                global_desc,
+            ),
+        ) in &module.imported_globals
+        {
             let import = imports.get(mod_name, item_name);
             if let Some(Import::Global(val)) = import {
                 if val.ty() == global_desc.ty {
diff --git a/src/runtime/instance.rs b/src/runtime/instance.rs
index c2eafc873..d5365eff9 100644
--- a/src/runtime/instance.rs
+++ b/src/runtime/instance.rs
@@ -1,18 +1,19 @@
+use crate::recovery::call_protected;
 use crate::runtime::{
     backing::{ImportBacking, LocalBacking},
     memory::LinearMemory,
-    module::{ItemName, Module, ModuleName},
+    module::{Export, Module},
     sig_registry::SigRegistry,
     table::TableBacking,
-    types::{FuncSig, Memory, Table, Val},
+    types::{FuncIndex, FuncSig, Memory, Table, Type, Val},
     vm,
 };
 use hashbrown::HashMap;
+use libffi::high::{arg as libffi_arg, call as libffi_call, CodePtr};
+use std::iter;
 use std::sync::Arc;
 
 pub struct Instance {
-    pub vmctx: vm::Ctx,
-
     backing: LocalBacking,
     import_backing: ImportBacking,
 
@@ -23,21 +24,101 @@ pub struct Instance {
 
 impl Instance {
     pub fn new(module: Arc<Module>, imports: &Imports) -> Result<Box<Instance>, String> {
-        let mut import_backing = ImportBacking::new(&*module, imports)?;
-        let mut backing = LocalBacking::new(&*module, &import_backing);
+        let import_backing = ImportBacking::new(&*module, imports)?;
+        let backing = LocalBacking::new(&*module, &import_backing);
 
         let sig_registry = SigRegistry::new();
 
-        let vmctx = vm::Ctx::new(&mut backing, &mut import_backing, &sig_registry);
-
         Ok(Box::new(Instance {
-            vmctx,
             backing,
             import_backing,
             module,
             sig_registry,
         }))
     }
+
+    /// Call an exported webassembly function given the export name.
+    /// Pass arguments by wrapping each one in the `Val` enum.
+    /// The returned value is also returned in a `Val`.
+    ///
+    /// This will eventually return `Result<Option<Vec<Val>>, String>` in
+    /// order to support multi-value returns.
+    pub fn call(&mut self, name: &str, args: &[Val]) -> Result<Option<Val>, String> {
+        let func_index = *self
+            .module
+            .exports
+            .get(name)
+            .ok_or_else(|| "there is no export with that name".to_string())
+            .and_then(|export| match export {
+                Export::Func(func_index) => Ok(func_index),
+                _ => Err("that export is not a function".to_string()),
+            })?;
+
+        // Check the function signature.
+        let sig_index = *self
+            .module
+            .signature_assoc
+            .get(func_index)
+            .expect("broken invariant, incorrect func index");
+        let signature = &self.module.signatures[sig_index];
+
+        assert!(
+            signature.returns.len() <= 1,
+            "multi-value returns not yet supported"
+        );
+
+        if !signature.check_sig(args) {
+            return Err("incorrect signature".to_string());
+        }
+
+        // the vmctx will be located at the same place on the stack the entire time that this
+        // wasm function is running.
+        let mut vmctx = vm::Ctx::new(
+            &mut self.backing,
+            &mut self.import_backing,
+            &self.sig_registry,
+        );
+        let vmctx_ptr = &mut vmctx as *mut vm::Ctx;
+
+        let libffi_args: Vec<_> = args
+            .iter()
+            .map(|val| match val {
+                Val::I32(ref x) => libffi_arg(x),
+                Val::I64(ref x) => libffi_arg(x),
+                Val::F32(ref x) => libffi_arg(x),
+                Val::F64(ref x) => libffi_arg(x),
+            })
+            .chain(iter::once(libffi_arg(&vmctx_ptr)))
+            .collect();
+
+        let func_ptr = CodePtr::from_ptr(
+            self.module
+                .functions
+                .resolve(&*self.module, name)
+                .expect("broken invariant, func resolver not synced with module.exports")
+                .cast()
+                .as_ptr(),
+        );
+
+        call_protected(|| {
+            signature
+                .returns
+                .first()
+                .map(|ty| match ty {
+                    Type::I32 => Val::I32(unsafe { libffi_call(func_ptr, &libffi_args) }),
+                    Type::I64 => Val::I64(unsafe { libffi_call(func_ptr, &libffi_args) }),
+                    Type::F32 => Val::F32(unsafe { libffi_call(func_ptr, &libffi_args) }),
+                    Type::F64 => Val::F64(unsafe { libffi_call(func_ptr, &libffi_args) }),
+                })
+                .or_else(|| {
+                    // call with no returns
+                    unsafe {
+                        libffi_call::<()>(func_ptr, &libffi_args);
+                    }
+                    None
+                })
+        })
+    }
 }
 
 #[derive(Debug)]
@@ -49,7 +130,7 @@ pub enum Import {
 }
 
 pub struct Imports {
-    map: HashMap<ModuleName, HashMap<ItemName, Import>>,
+    map: HashMap<String, HashMap<String, Import>>,
 }
 
 impl Imports {
@@ -59,14 +140,14 @@ impl Imports {
         }
     }
 
-    pub fn add(&mut self, module: ModuleName, name: ItemName, import: Import) {
+    pub fn add(&mut self, module: String, name: String, import: Import) {
         self.map
             .entry(module)
             .or_insert(HashMap::new())
             .insert(name, import);
     }
 
-    pub fn get(&self, module: &[u8], name: &[u8]) -> Option<&Import> {
+    pub fn get(&self, module: &str, name: &str) -> Option<&Import> {
         self.map.get(module).and_then(|m| m.get(name))
     }
 }
diff --git a/src/runtime/mod.rs b/src/runtime/mod.rs
index 6396cbf14..6491a82e8 100644
--- a/src/runtime/mod.rs
+++ b/src/runtime/mod.rs
@@ -10,7 +10,7 @@ pub mod vm;
 
 pub use self::backend::{Compiler, FuncResolver};
 pub use self::instance::{Import, Imports, Instance};
-pub use self::module::{ItemName, Module, ModuleName};
+pub use self::module::Module;
 
 /// Compile a webassembly module using the provided compiler and linked with the provided imports.
 pub fn compile(
diff --git a/src/runtime/module.rs b/src/runtime/module.rs
index 4afb15bd7..c5cc82638 100644
--- a/src/runtime/module.rs
+++ b/src/runtime/module.rs
@@ -3,6 +3,7 @@ use crate::runtime::types::{
     FuncIndex, FuncSig, Global, GlobalDesc, GlobalIndex, Map, Memory, MemoryIndex, SigIndex, Table,
     TableIndex,
 };
+use hashbrown::HashMap;
 
 /// This is used to instantiate a new webassembly module.
 pub struct Module {
@@ -16,7 +17,7 @@ pub struct Module {
     pub imported_tables: Map<(ImportName, Table), TableIndex>,
     pub imported_globals: Map<(ImportName, GlobalDesc), GlobalIndex>,
 
-    pub exported: Vec<(ItemName, Export)>,
+    pub exports: HashMap<String, Export>,
 
     pub data_initializers: Vec<DataInitializer>,
     pub start_func: FuncIndex,
@@ -25,9 +26,11 @@ pub struct Module {
     pub signatures: Map<FuncSig, SigIndex>,
 }
 
-pub type ModuleName = Vec<u8>;
-pub type ItemName = Vec<u8>;
-pub type ImportName = (ModuleName, ItemName);
+#[derive(Debug, Clone)]
+pub struct ImportName {
+    pub module: String,
+    pub name: String,
+}
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum Export {
diff --git a/src/runtime/types.rs b/src/runtime/types.rs
index f863d411d..026f096a8 100644
--- a/src/runtime/types.rs
+++ b/src/runtime/types.rs
@@ -126,6 +126,17 @@ pub struct FuncSig {
     pub returns: Vec<Type>,
 }
 
+impl FuncSig {
+    pub fn check_sig(&self, params: &[Val]) -> bool {
+        self.params.len() == params.len()
+            && self
+                .params
+                .iter()
+                .zip(params.iter().map(|val| val.ty()))
+                .all(|(t0, ref t1)| t0 == t1)
+    }
+}
+
 pub trait MapIndex {
     fn new(index: usize) -> Self;
     fn index(&self) -> usize;