Start work on object loader using llvm's RuntimeDyld api.

Cargo.lock

@@ -262,6 +262,28 @@ dependencies = [
  "generic-array 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "dlopen"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "dlopen_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "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)",
+ "libc 0.2.49 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "dlopen_derive"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.49 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "either"
 version = "1.5.1"
@@ -469,10 +491,16 @@ dependencies = [
 name = "llvm-backend"
 version = "0.1.0"
 dependencies = [
+ "cc 1.0.29 (registry+https://github.com/rust-lang/crates.io-index)",
+ "dlopen 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "goblin 0.0.20 (registry+https://github.com/rust-lang/crates.io-index)",
  "hashbrown 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "inkwell 0.1.0 (git+https://github.com/TheDan64/inkwell?branch=llvm7-0)",
+ "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tempfile 3.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "wabt 0.7.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasmer-runtime-core 0.1.2",
  "wasmparser 0.28.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1362,6 +1390,8 @@ dependencies = [
 "checksum cranelift-native 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)" = "474bee81d620a473bf43411a3d6f10ffbf7965141dc5e5b76d8d2151dde3285d"
 "checksum cranelift-wasm 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)" = "49723365dab9a48b354bdc24cb6d9d5719bc1d3b858ffd2ea179d0d7d885804a"
 "checksum digest 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "05f47366984d3ad862010e22c7ce81a7dbcaebbdfb37241a620f8b6596ee135c"
+"checksum dlopen 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "f8c301a18a3404a48d5d078e86b011ac834a6c4c742217e9aa8ceadd8a7e09e0"
+"checksum dlopen_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6e16e4e343d6090ba47113c55bf6aa94e9b1eb5ab0c5abc9510d4c15074f30e9"
 "checksum either 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c67353c641dc847124ea1902d69bd753dee9bb3beff9aa3662ecf86c971d1fac"
 "checksum enum-methods 0.0.8 (registry+https://github.com/rust-lang/crates.io-index)" = "7798e7da2d4cb0d6d6fc467e8d6b5bf247e9e989f786dde1732d79899c32bb10"
 "checksum env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "afb070faf94c85d17d50ca44f6ad076bce18ae92f0037d350947240a36e9d42e"

lib/llvm-backend/Cargo.toml

@@ -11,6 +11,14 @@ inkwell = { git = "https://github.com/TheDan64/inkwell", branch = "llvm7-0" }
 hashbrown = "0.1.8"
 smallvec = "0.6.8"
 goblin = "0.0.20"
+dlopen = "0.1.6"
+tempfile = "3.0.7"
+
+[build-dependencies]
+cc = "1.0"
+lazy_static = "1.2.0"
+regex = "1.1.0"
+semver = "0.9"
 
 [dev-dependencies]
 wabt = "0.7.4"

lib/llvm-backend/build.rs

@@ -0,0 +1,213 @@
+//! This file was mostly taken from the llvm-sys crate.
+//! (https://bitbucket.org/tari/llvm-sys.rs/src/21ab524ec4df1450035df895209c3f8fbeb8775f/build.rs?at=default&fileviewer=file-view-default)
+
+use lazy_static::lazy_static;
+use regex::Regex;
+use semver::Version;
+use std::env;
+use std::ffi::OsStr;
+use std::io::{self, ErrorKind};
+use std::path::PathBuf;
+use std::process::Command;
+
+lazy_static! {
+    /// LLVM version used by this version of the crate.
+    static ref CRATE_VERSION: Version = {
+        let crate_version = Version::parse(env!("CARGO_PKG_VERSION"))
+            .expect("Crate version is somehow not valid semver");
+        Version {
+            major: crate_version.major / 10,
+            minor: crate_version.major % 10,
+            .. crate_version
+        }
+    };
+
+    static ref LLVM_CONFIG_BINARY_NAMES: Vec<String> = {
+        vec![
+            "llvm-config".into(),
+            // format!("llvm-config-{}", CRATE_VERSION.major),
+            // format!("llvm-config-{}.{}", CRATE_VERSION.major, CRATE_VERSION.minor),
+        ]
+    };
+
+    /// Filesystem path to an llvm-config binary for the correct version.
+    static ref LLVM_CONFIG_PATH: PathBuf = {
+        // Try llvm-config via PATH first.
+        if let Some(name) = locate_system_llvm_config() {
+            return name.into();
+        } else {
+            println!("Didn't find usable system-wide LLVM.");
+        }
+
+        // Did the user give us a binary path to use? If yes, try
+        // to use that and fail if it doesn't work.
+        let binary_prefix_var = "LLVM_SYS_70_PREFIX";
+
+        let path = if let Some(path) = env::var_os(&binary_prefix_var) {
+            Some(path.to_str().unwrap().to_owned())
+        } else if let Ok(mut file) = std::fs::File::open(".llvmenv") {
+            use std::io::Read;
+            let mut s = String::new();
+            file.read_to_string(&mut s).unwrap();
+            Some(s)
+        } else {
+            None
+        };
+
+        if let Some(path) = path {
+            for binary_name in LLVM_CONFIG_BINARY_NAMES.iter() {
+                let mut pb: PathBuf = path.clone().into();
+                pb.push("bin");
+                pb.push(binary_name);
+
+                let ver = llvm_version(&pb)
+                    .expect(&format!("Failed to execute {:?}", &pb));
+                if is_compatible_llvm(&ver) {
+                    return pb;
+                } else {
+                    println!("LLVM binaries specified by {} are the wrong version.
+                              (Found {}, need {}.)", binary_prefix_var, ver, *CRATE_VERSION);
+                }
+            }
+        }
+
+        println!("No suitable version of LLVM was found system-wide or pointed
+                  to by {}.
+                  
+                  Consider using `llvmenv` to compile an appropriate copy of LLVM, and
+                  refer to the llvm-sys documentation for more information.
+                  
+                  llvm-sys: https://crates.io/crates/llvm-sys
+                  llvmenv: https://crates.io/crates/llvmenv", binary_prefix_var);
+        panic!("Could not find a compatible version of LLVM");
+    };
+}
+
+/// Try to find a system-wide version of llvm-config that is compatible with
+/// this crate.
+///
+/// Returns None on failure.
+fn locate_system_llvm_config() -> Option<&'static str> {
+    for binary_name in LLVM_CONFIG_BINARY_NAMES.iter() {
+        match llvm_version(binary_name) {
+            Ok(ref version) if is_compatible_llvm(version) => {
+                // Compatible version found. Nice.
+                return Some(binary_name);
+            }
+            Ok(version) => {
+                // Version mismatch. Will try further searches, but warn that
+                // we're not using the system one.
+                println!(
+                    "Found LLVM version {} on PATH, but need {}.",
+                    version, *CRATE_VERSION
+                );
+            }
+            Err(ref e) if e.kind() == ErrorKind::NotFound => {
+                // Looks like we failed to execute any llvm-config. Keep
+                // searching.
+            }
+            // Some other error, probably a weird failure. Give up.
+            Err(e) => panic!("Failed to search PATH for llvm-config: {}", e),
+        }
+    }
+
+    None
+}
+
+/// Check whether the given LLVM version is compatible with this version of
+/// the crate.
+fn is_compatible_llvm(llvm_version: &Version) -> bool {
+    let strict = env::var_os(format!(
+        "LLVM_SYS_{}_STRICT_VERSIONING",
+        env!("CARGO_PKG_VERSION_MAJOR")
+    ))
+    .is_some()
+        || cfg!(feature = "strict-versioning");
+    if strict {
+        llvm_version.major == CRATE_VERSION.major && llvm_version.minor == CRATE_VERSION.minor
+    } else {
+        llvm_version.major >= CRATE_VERSION.major
+            || (llvm_version.major == CRATE_VERSION.major
+                && llvm_version.minor >= CRATE_VERSION.minor)
+    }
+}
+
+/// Get the output from running `llvm-config` with the given argument.
+///
+/// Lazily searches for or compiles LLVM as configured by the environment
+/// variables.
+fn llvm_config(arg: &str) -> String {
+    llvm_config_ex(&*LLVM_CONFIG_PATH, arg).expect("Surprising failure from llvm-config")
+}
+
+/// Invoke the specified binary as llvm-config.
+///
+/// Explicit version of the `llvm_config` function that bubbles errors
+/// up.
+fn llvm_config_ex<S: AsRef<OsStr>>(binary: S, arg: &str) -> io::Result<String> {
+    Command::new(binary)
+        .arg(arg)
+        .arg("--link-static") // Don't use dylib for >= 3.9
+        .output()
+        .map(|output| {
+            String::from_utf8(output.stdout).expect("Output from llvm-config was not valid UTF-8")
+        })
+}
+
+/// Get the LLVM version using llvm-config.
+fn llvm_version<S: AsRef<OsStr>>(binary: S) -> io::Result<Version> {
+    let version_str = llvm_config_ex(binary.as_ref(), "--version")?;
+
+    // LLVM isn't really semver and uses version suffixes to build
+    // version strings like '3.8.0svn', so limit what we try to parse
+    // to only the numeric bits.
+    let re = Regex::new(r"^(?P<major>\d+)\.(?P<minor>\d+)(?:\.(?P<patch>\d+))??").unwrap();
+    let c = re
+        .captures(&version_str)
+        .expect("Could not determine LLVM version from llvm-config.");
+
+    // some systems don't have a patch number but Version wants it so we just append .0 if it isn't
+    // there
+    let s = match c.name("patch") {
+        None => format!("{}.0", &c[0]),
+        Some(_) => c[0].to_string(),
+    };
+    Ok(Version::parse(&s).unwrap())
+}
+
+fn get_llvm_cxxflags() -> String {
+    let output = llvm_config("--cxxflags");
+
+    // llvm-config includes cflags from its own compilation with --cflags that
+    // may not be relevant to us. In particularly annoying cases, these might
+    // include flags that aren't understood by the default compiler we're
+    // using. Unless requested otherwise, clean CFLAGS of options that are
+    // known to be possibly-harmful.
+    let no_clean = env::var_os(format!(
+        "LLVM_SYS_{}_NO_CLEAN_CFLAGS",
+        env!("CARGO_PKG_VERSION_MAJOR")
+    ))
+    .is_some();
+    if no_clean || cfg!(target_env = "msvc") {
+        // MSVC doesn't accept -W... options, so don't try to strip them and
+        // possibly strip something that should be retained. Also do nothing if
+        // the user requests it.
+        return output;
+    }
+
+    output
+        .split(&[' ', '\n'][..])
+        .filter(|word| !word.starts_with("-W"))
+        .collect::<Vec<_>>()
+        .join(" ")
+}
+
+fn main() {
+    std::env::set_var("CXXFLAGS", get_llvm_cxxflags());
+    cc::Build::new()
+        .cpp(true)
+        .file("cpp/object_loader.cpp")
+        .compile("llvm-backend");
+
+    println!("cargo:rustc-link-lib=static=llvm-backend");
+}

lib/llvm-backend/cpp/object_loader.cpp

@@ -0,0 +1,96 @@
+#include "object_loader.hh"
+#include <llvm/ExecutionEngine/RuntimeDyld.h>
+#include <iostream>
+
+class MemoryManager : llvm::RuntimeDyld::MemoryManager {
+public:
+    MemoryManager() {}
+
+    virtual ~MemoryManager() {}
+
+    virtual uint8_t* allocateCodeSection(uintptr_t Size, unsigned Alignment, unsigned SectionID, llvm::StringRef SectionName) override {
+        return nullptr;
+    }
+
+    virtual uint8_t* allocateDataSection(uintptr_t Size, unsigned Alignment, unsigned SectionID, llvm::StringRef SectionName, bool isReadOnly) override {
+        return nullptr;
+    }
+
+    virtual void reserveAllocationSpace(
+        uintptr_t code_size,
+        uint32_t code_align,
+        uintptr_t read_data_size,
+        uint32_t read_data_align,
+        uintptr_t read_write_data_size,
+        uint32_t read_write_data_align
+    ) override {
+        
+    }
+
+    /* Turn on the `reserveAllocationSpace` callback. */
+    virtual bool needsToReserveAllocationSpace() override {
+        return true;
+    }
+
+    virtual void registerEHFrames(uint8_t* Addr, uint64_t LoadAddr, size_t Size) override {
+
+    }
+
+    virtual void deregisterEHFrames() override {
+
+    }
+
+    virtual bool finalizeMemory(std::string *ErrMsg = nullptr) override {
+        
+
+        return false;
+    }
+
+    virtual void notifyObjectLoaded(llvm::RuntimeDyld &RTDyld, const llvm::object::ObjectFile &Obj) override {
+        
+    }
+private:
+    struct Section {
+        uint8_t* base;
+        size_t num_pages;
+        size_t num_commited_bytes;
+    };
+
+    uint8_t *image_base;
+    size_t num_allocated_pages;
+
+    Section code_section, read_section, readwrite_section;
+
+
+};
+
+class SymbolLookup : llvm::JITSymbolResolver {
+public:
+    virtual llvm::Expected<LookupResult> lookup(const LookupSet& symbols) override {
+        LookupResult result;
+
+        for (auto symbol : symbols) {
+            result.emplace(symbol, symbol_lookup(symbol));
+        }
+
+        return result;
+    }
+
+    virtual llvm::Expected<LookupFlagsResult> lookupFlags(const LookupSet& symbols) override {
+        LookupFlagsResult result;
+
+        for (auto symbol : symbols) {
+            result.emplace(symbol, symbol_lookup(symbol).getFlags());
+        }
+
+        return result;
+    }
+
+private:
+    llvm::JITEvaluatedSymbol symbol_lookup(llvm::StringRef name) {
+        std::cout << "symbol name: " << (std::string)name << std::endl;
+        uint64_t addr = 0;
+
+        return llvm::JITEvaluatedSymbol(addr, llvm::JITSymbolFlags::None);
+    }
+};

lib/llvm-backend/cpp/object_loader.hh

@@ -0,0 +1,40 @@
+#include <cstddef>
+#include <cstdint>
+
+typedef enum {
+    PROTECT_NONE,
+    PROTECT_READ,
+    PROTECT_READ_WRITE,
+    PROTECT_READ_EXECUTE,
+} mem_protect_t;
+
+typedef enum {
+    RESULT_OK,
+    RESULT_ALLOCATE_FAILURE,
+    RESULT_PROTECT_FAILURE,
+    RESULT_DEALLOC_FAILURE,
+    RESULT_OBJECT_LOAD_FAILURE,
+} result_t;
+
+typedef result_t (*alloc_memory_t)(size_t size, mem_protect_t protect, uint8_t** ptr_out, size_t* size_out);
+typedef result_t (*protect_memory_t)(uint8_t* ptr, size_t size, mem_protect_t protect);
+typedef result_t (*dealloc_memory_t)(uint8_t* ptr, size_t size);
+typedef uintptr_t (*lookup_vm_symbol_t)(char* name_ptr, size_t name_size);
+
+typedef struct {
+    /* Memory management. */
+    alloc_memory_t alloc_memory;
+    protect_memory_t protect_memory;
+    dealloc_memory_t dealloc_memory;
+
+    lookup_vm_symbol_t lookup_vm_symbol;
+} callbacks_t;
+
+extern "C" {
+    result_t object_load(uint8_t* mem_ptr, size_t mem_size, callbacks_t* callbacks) {
+        return RESULT_OK;
+    }
+
+    void test_cpp() {
+    }
+}

lib/llvm-backend/src/backend.rs

@@ -1,45 +1,76 @@
+use crate::intrinsics::Intrinsics;
+use dlopen::symbor::Library;
 use inkwell::{
     module::Module,
-    execution_engine::{ExecutionEngine, JitFunction},
+    targets::{CodeModel, FileType, InitializationConfig, RelocMode, Target, TargetMachine},
+    OptimizationLevel,
 };
-use crate::intrinsics::Intrinsics;
-use std::ptr::NonNull;
+use std::{io::Write, ptr::NonNull};
+use tempfile::NamedTempFile;
 use wasmer_runtime_core::{
-    module::ModuleInner,
-    types::LocalFuncIndex,
-    structures::TypedIndex,
-    backend::{FuncResolver, vm},
+    backend::FuncResolver, module::ModuleInner, structures::TypedIndex, types::LocalFuncIndex, vm,
 };
 
 pub struct LLVMBackend {
-    exec_engine: ExecutionEngine,
+    tempfile: NamedTempFile,
+    library: Library,
 }
 
 impl LLVMBackend {
     pub fn new(module: Module, intrinsics: Intrinsics) -> Self {
-        let exec_engine = module.create_jit_execution_engine(OptimizationLevel::Default).unwrap();
+        Target::initialize_x86(&InitializationConfig {
+            asm_parser: true,
+            asm_printer: true,
+            base: true,
+            disassembler: true,
+            info: true,
+            machine_code: true,
+        });
+        let triple = TargetMachine::get_default_triple().to_string();
+        let target = Target::from_triple(&triple).unwrap();
+        let target_machine = target
+            .create_target_machine(
+                &triple,
+                &TargetMachine::get_host_cpu_name().to_string(),
+                &TargetMachine::get_host_cpu_features().to_string(),
+                OptimizationLevel::Default,
+                RelocMode::PIC,
+                CodeModel::Default,
+            )
+            .unwrap();
 
-        exec_engine.add_global_mapping(&intrinsics.memory_grow_dynamic_local, vmcalls::local_dynamic_memory_grow as usize);
-        exec_engine.add_global_mapping(&intrinsics.memory_grow_static_local, vmcalls::local_static_memory_grow as usize);
-        exec_engine.add_global_mapping(&intrinsics.memory_grow_dynamic_import, vmcalls::imported_dynamic_memory_grow as usize);
-        exec_engine.add_global_mapping(&intrinsics.memory_grow_static_import, vmcalls::imported_static_memory_grow as usize);
-        exec_engine.add_global_mapping(&intrinsics.memory_size_dynamic_local, vmcalls::local_dynamic_memory_size as usize);
-        exec_engine.add_global_mapping(&intrinsics.memory_size_static_local, vmcalls::local_static_memory_size as usize);
-        exec_engine.add_global_mapping(&intrinsics.memory_size_dynamic_import, vmcalls::imported_dynamic_memory_size as usize);
-        exec_engine.add_global_mapping(&intrinsics.memory_size_static_import, vmcalls::imported_static_memory_size as usize);
+        let memory_buffer = target_machine
+            .write_to_memory_buffer(&module, FileType::Object)
+            .unwrap();
 
-        Self { exec_engine }
+        let mut tempfile = NamedTempFile::new().unwrap();
+        tempfile.write_all(memory_buffer.as_slice()).unwrap();
+        tempfile.flush().unwrap();
+
+        let library = Library::open(tempfile.path()).unwrap();
+
+        Self { tempfile, library }
     }
 }
 
 impl FuncResolver for LLVMBackend {
-    fn get(&self, module: &ModuleInner, local_func_index: LocalFuncIndex) -> Option<NonNull<vm::Func>> {
+    fn get(
+        &self,
+        module: &ModuleInner,
+        local_func_index: LocalFuncIndex,
+    ) -> Option<NonNull<vm::Func>> {
         let index = module.info.imported_functions.len() + local_func_index.index();
-        let name = format!("fn{}", index);
+        let name = if cfg!(macos) {
+            format!("_fn{}", index)
+        } else {
+            format!("fn{}", index)
+        };
 
         unsafe {
-            let func: JitFunction<unsafe extern fn()> = self.exec_engine.get_function(&name).ok()?;
-            
+            self.library
+                .symbol::<NonNull<vm::Func>>(&name)
+                .ok()
+                .map(|symbol| *symbol)
         }
     }
 }

lib/llvm-backend/src/code.rs

@@ -481,6 +481,7 @@ fn parse_function(
                 // Emit an unreachable instruction.
                 // If llvm cannot prove that this is never touched,
                 // it will emit a `ud2` instruction on x86_64 arches.
+                ctx.build_trap();
                 builder.build_unreachable();
                 state.reachable = false;
             }
@@ -623,7 +624,8 @@ fn parse_function(
                 }
             }
             Operator::CallIndirect { index, table_index } => {
-                let expected_dynamic_sigindex = ctx.dynamic_sigindex(SigIndex::new(index as usize));
+                let sig_index = SigIndex::new(index as usize);
+                let expected_dynamic_sigindex = ctx.dynamic_sigindex(sig_index);
                 let (table_base, table_bound) = ctx.table(TableIndex::new(table_index as usize));
                 let func_index = state.pop1()?.into_int_value();
 
@@ -651,12 +653,10 @@ fn parse_function(
                                 "func_ptr",
                             )
                             .into_pointer_value(),
-                        builder
-                            .build_load(
+                        builder.build_load(
                             builder.build_struct_gep(anyfunc_struct_ptr, 1, "ctx_ptr_ptr"),
                             "ctx_ptr",
-                            )
-                            .into_pointer_value(),
+                        ),
                         builder
                             .build_load(
                                 builder.build_struct_gep(anyfunc_struct_ptr, 2, "sigindex_ptr"),
@@ -685,21 +685,49 @@ fn parse_function(
                     )
                     .try_as_basic_value()
                     .left()
-                    .unwrap();
+                    .unwrap()
+                    .into_int_value();
 
                 let continue_block = context.append_basic_block(&function, "continue_block");
                 let sigindices_notequal_block =
                     context.append_basic_block(&function, "sigindices_notequal_block");
+                builder.build_conditional_branch(
+                    sigindices_equal,
+                    &continue_block,
+                    &sigindices_notequal_block,
+                );
 
                 builder.position_at_end(&sigindices_notequal_block);
+                ctx.build_trap();
                 builder.build_unreachable();
                 builder.position_at_end(&continue_block);
 
-                println!("func ptr: {:#?}", func_ptr);
-                println!("ctx ptr: {:#?}", ctx_ptr);
-                println!("found dynamic sigindex: {:#?}", found_dynamic_sigindex);
+                let wasmer_fn_sig = &info.signatures[sig_index];
+                let fn_ty = signatures[sig_index];
 
-                unimplemented!("{}, {}", index, table_index);
+                let pushed_args = state.popn_save(wasmer_fn_sig.params().len())?;
+
+                let args: Vec<_> = std::iter::once(ctx_ptr)
+                    .chain(pushed_args.into_iter())
+                    .collect();
+                println!("args: {:?}", args);
+
+                let typed_func_ptr = builder.build_pointer_cast(
+                    func_ptr,
+                    fn_ty.ptr_type(AddressSpace::Generic),
+                    "typed_func_ptr",
+                );
+
+                let call_site = builder.build_call(typed_func_ptr, &args, "indirect_call");
+
+                match wasmer_fn_sig.returns() {
+                    [] => {}
+                    [_] => {
+                        let value = call_site.try_as_basic_value().left().unwrap();
+                        state.push1(value);
+                    }
+                    returns @ _ => unimplemented!("multi-value returns"),
+                }
             }
 
             /***************************

lib/llvm-backend/src/intrinsics.rs

@@ -64,6 +64,7 @@ pub struct Intrinsics {
     pub copysign_f64: FunctionValue,
 
     pub expect_i1: FunctionValue,
+    pub trap: FunctionValue,
 
     pub void_ty: VoidType,
     pub i1_ty: IntType,
@@ -255,6 +256,7 @@ impl Intrinsics {
             copysign_f64: module.add_function("llvm.copysign.f64", ret_f64_take_f64_f64, None),
 
             expect_i1: module.add_function("llvm.expect.i1", ret_i1_take_i1_i1, None),
+            trap: module.add_function("llvm.trap", void_ty.fn_type(&[], false), None),
 
             void_ty,
             i1_ty,
@@ -695,7 +697,9 @@ impl<'a> CtxType<'a> {
         (imported_func_cache.func_ptr, imported_func_cache.ctx_ptr)
     }
 
-    // pub fn table(&mut self, table_index: TableIndex, elem_index: IntValue) ->
+    pub fn build_trap(&self) {
+        self.builder.build_call(self.intrinsics.trap, &[], "trap");
+    }
 }
 
 // pub struct Ctx {

lib/llvm-backend/src/lib.rs

@@ -10,11 +10,11 @@ use wasmer_runtime_core::{
     module::ModuleInner,
 };
 
+mod backend;
 mod code;
 mod intrinsics;
 mod read_info;
 mod state;
-// mod backend;
 
 pub struct LLVMCompiler {
     _private: (),
@@ -28,13 +28,61 @@ impl LLVMCompiler {
 
 impl Compiler for LLVMCompiler {
     fn compile(&self, wasm: &[u8], _: Token) -> Result<ModuleInner, CompileError> {
-        let (_info, _code_reader) = read_info::read_module(wasm).unwrap();
+        let (info, code_reader) = read_info::read_module(wasm).unwrap();
+        let (module, intrinsics) = code::parse_function_bodies(&info, code_reader).unwrap();
 
+        let backend = backend::LLVMBackend::new(module, intrinsics);
+
+        // Create placeholder values here.
+        let (protected_caller, cache_gen) = {
+            use wasmer_runtime_core::backend::{
+                sys::Memory, CacheGen, ProtectedCaller, UserTrapper,
+            };
+            use wasmer_runtime_core::cache::Error as CacheError;
+            use wasmer_runtime_core::error::RuntimeResult;
+            use wasmer_runtime_core::module::ModuleInfo;
+            use wasmer_runtime_core::types::{FuncIndex, Value};
+            use wasmer_runtime_core::vm;
+            struct Placeholder;
+            impl ProtectedCaller for Placeholder {
+                fn call(
+                    &self,
+                    _module: &ModuleInner,
+                    _func_index: FuncIndex,
+                    _params: &[Value],
+                    _import_backing: &vm::ImportBacking,
+                    _vmctx: *mut vm::Ctx,
+                    _: Token,
+                ) -> RuntimeResult<Vec<Value>> {
+                    Ok(vec![])
+                }
+                fn get_early_trapper(&self) -> Box<dyn UserTrapper> {
                     unimplemented!()
                 }
+            }
+            impl CacheGen for Placeholder {
+                fn generate_cache(
+                    &self,
+                    module: &ModuleInner,
+                ) -> Result<(Box<ModuleInfo>, Box<[u8]>, Memory), CacheError> {
+                    unimplemented!()
+                }
+            }
+
+            (Box::new(Placeholder), Box::new(Placeholder))
+        };
+
+        Ok(ModuleInner {
+            func_resolver: Box::new(backend),
+            protected_caller,
+            cache_gen,
+
+            info,
+        })
+    }
 
     unsafe fn from_cache(&self, _artifact: Artifact, _: Token) -> Result<ModuleInner, CacheError> {
-        unimplemented!()
+        unimplemented!("the llvm backend doesn't support caching yet")
     }
 }
 
@@ -55,14 +103,9 @@ fn test_read_module() {
             get_local 0
             i32.const 0
             call_indirect (type $t0)
-            memory.grow
         )
         (func $foobar (type $t0)
             get_local 0
-        )
-        (func $bar (type $t0) (param i32) (result i32)
-            get_local 0
-            call $foo
         ))
     "#;
     let wasm = wat2wasm(wat).unwrap();
@@ -71,86 +114,50 @@ fn test_read_module() {
 
     let (module, intrinsics) = code::parse_function_bodies(&info, code_reader).unwrap();
 
-    {
-        Target::initialize_x86(&InitializationConfig {
-            asm_parser: true,
-            asm_printer: true,
-            base: true,
-            disassembler: true,
-            info: true,
-            machine_code: true,
-        });
-        let triple = TargetMachine::get_default_triple().to_string();
-        let target = Target::from_triple(&triple).unwrap();
-        let target_machine = target
-            .create_target_machine(
-                &triple,
-                &TargetMachine::get_host_cpu_name().to_string(),
-                &TargetMachine::get_host_cpu_features().to_string(),
-                OptimizationLevel::Default,
-                RelocMode::PIC,
-                CodeModel::Default,
-            )
-            .unwrap();
+    // let backend = backend::LLVMBackend::new(module, intrinsics);
 
-        let memory_buffer = target_machine
-            .write_to_memory_buffer(&module, FileType::Object)
-            .unwrap();
-        // std::fs::write("memory_buffer", memory_buffer.as_slice()).unwrap();
-        let mem_buf_slice = memory_buffer.as_slice();
-
-        let macho = goblin::mach::MachO::parse(mem_buf_slice, 0).unwrap();
-        let symbols = macho.symbols.as_ref().unwrap();
-        let relocations = macho.relocations().unwrap();
-        for (_, reloc_iter, section) in relocations.into_iter() {
-            println!("section: {:#?}", section);
-            for reloc_info in reloc_iter {
-                let reloc_info = reloc_info.unwrap();
-                println!("\treloc_info: {:#?}", reloc_info);
-                println!(
-                    "\tsymbol: {:#?}",
-                    symbols.get(reloc_info.r_symbolnum()).unwrap()
-                );
-            }
-        }
+    extern "C" {
+        fn test_cpp();
     }
 
-    let exec_engine = module
-        .create_jit_execution_engine(OptimizationLevel::Default)
-        .unwrap();
+    unsafe { test_cpp() };
 
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_grow_dynamic_local,
-        vmcalls::local_dynamic_memory_grow as usize,
-    );
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_grow_static_local,
-        vmcalls::local_static_memory_grow as usize,
-    );
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_grow_dynamic_import,
-        vmcalls::imported_dynamic_memory_grow as usize,
-    );
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_grow_static_import,
-        vmcalls::imported_static_memory_grow as usize,
-    );
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_size_dynamic_local,
-        vmcalls::local_dynamic_memory_size as usize,
-    );
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_size_static_local,
-        vmcalls::local_static_memory_size as usize,
-    );
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_size_dynamic_import,
-        vmcalls::imported_dynamic_memory_size as usize,
-    );
-    exec_engine.add_global_mapping(
-        &intrinsics.memory_size_static_import,
-        vmcalls::imported_static_memory_size as usize,
-    );
+    // let exec_engine = module
+    //     .create_jit_execution_engine(OptimizationLevel::Default)
+    //     .unwrap();
+
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_grow_dynamic_local,
+    //     vmcalls::local_dynamic_memory_grow as usize,
+    // );
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_grow_static_local,
+    //     vmcalls::local_static_memory_grow as usize,
+    // );
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_grow_dynamic_import,
+    //     vmcalls::imported_dynamic_memory_grow as usize,
+    // );
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_grow_static_import,
+    //     vmcalls::imported_static_memory_grow as usize,
+    // );
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_size_dynamic_local,
+    //     vmcalls::local_dynamic_memory_size as usize,
+    // );
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_size_static_local,
+    //     vmcalls::local_static_memory_size as usize,
+    // );
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_size_dynamic_import,
+    //     vmcalls::imported_dynamic_memory_size as usize,
+    // );
+    // exec_engine.add_global_mapping(
+    //     &intrinsics.memory_size_static_import,
+    //     vmcalls::imported_static_memory_size as usize,
+    // );
 
     // unsafe {
     //     let func: JitFunction<unsafe extern fn(*mut u8, i32) -> i32> = exec_engine.get_function("fn0").unwrap();