Fix crashing cli args

src/apis/emscripten/mod.rs

@@ -19,7 +19,7 @@ mod utils;
 mod varargs;
 
 pub use self::storage::{align_memory, static_alloc};
-pub use self::utils::{is_emscripten_module, copy_cstr_array_into_wasm_stack};
+pub use self::utils::{is_emscripten_module, copy_cstr_array_into_wasm, allocate_on_stack, allocate_cstr_on_stack};
 
 // TODO: Magic number - how is this calculated?
 const TOTAL_STACK: u32 = 5242880;

src/apis/emscripten/utils.rs

@@ -20,7 +20,7 @@ pub fn is_emscripten_module(module: &Module) -> bool {
 pub unsafe fn copy_cstr_into_wasm(instance: &mut Instance, cstr: *const c_char) -> u32 {
     let s = CStr::from_ptr(cstr).to_str().unwrap();
     let cstr_len = s.len();
-    let space_offset = (instance.emscripten_data.as_ref().unwrap().malloc)(cstr_len as _, instance);
+    let space_offset = (instance.emscripten_data.as_ref().unwrap().malloc)((cstr_len as i32) + 1, instance);
     let raw_memory = instance.memory_offset_addr(0, space_offset as _) as *mut u8;
     let slice = slice::from_raw_parts_mut(raw_memory, cstr_len);
 
@@ -33,18 +33,8 @@ pub unsafe fn copy_cstr_into_wasm(instance: &mut Instance, cstr: *const c_char)
     space_offset
 }
 
-pub unsafe fn copy_cstr_into_wasm_stack(instance: &mut Instance, cstr: *const c_char) -> u32 {
-    let s = CStr::from_ptr(cstr).to_str().unwrap();
-    let cstr_len = s.len();
-    let space_offset = (instance.emscripten_data.as_ref().unwrap().stack_alloc)((cstr_len as u32) + 1, instance);
-    let raw_memory = instance.memory_offset_addr(0, space_offset as _) as *mut u8;
-    let slice = slice::from_raw_parts_mut(raw_memory, cstr_len);
-
-    for (byte, loc) in s.bytes().zip(slice.iter_mut()) {
-        *loc = byte;
-    }
-
-    *raw_memory.add(cstr_len) = 0;
+pub unsafe fn copy_cstr_array_into_wasm(array_count: u32, array: *mut *mut c_char, instance: &mut Instance) -> u32 {
+    let array_offset = (instance.emscripten_data.as_ref().unwrap().malloc)((array_count as usize * size_of::<u32>()) as _, instance);
 
     space_offset
 }
@@ -69,6 +59,25 @@ pub unsafe fn copy_cstr_array_into_wasm_stack(array_count: u32, array: *mut *mut
     array_offset
 }
 
+pub unsafe fn allocate_on_stack<'a, T: Copy>(count: u32, instance: &'a Instance) -> (u32, &'a mut [T]) {
+    let offset = (instance.emscripten_data.as_ref().unwrap().stack_alloc)(count * (size_of::<T>() as u32), instance);
+    let addr = instance.memory_offset_addr(0, offset as _) as *mut T;
+    let slice = slice::from_raw_parts_mut(addr, count as usize);
+
+    (offset, slice)
+}
+
+pub unsafe fn allocate_cstr_on_stack<'a>(s: &str, instance: &'a Instance) -> (u32, &'a [u8]) {
+    let (offset, slice) = allocate_on_stack((s.len() + 1) as u32, instance);
+
+    use std::iter;
+    for (byte, loc) in s.bytes().chain(iter::once(0)).zip(slice.iter_mut()) {
+        *loc = byte;
+    }
+
+    (offset, slice)
+}
+
 pub unsafe fn copy_terminated_array_of_cstrs(
     _instance: &mut Instance,
     cstrs: *mut *mut c_char,

src/bin/wasmer.rs

@@ -7,7 +7,7 @@ use std::io::Read;
 use std::path::PathBuf;
 use std::process::exit;
 
-use apis::emscripten::copy_cstr_array_into_wasm_stack;
+use apis::emscripten::{allocate_on_stack, allocate_cstr_on_stack};
 use structopt::StructOpt;
 
 use wasmer::*;
@@ -91,7 +91,7 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
         let main: extern "C" fn(u32, u32, &webassembly::Instance) =
             get_instance_function!(instance, func_index);
 
-        let (argc, argv) = get_module_arguments(options, &mut instance);
+        let (argc, argv) = store_module_arguments(options, &mut instance);
 
         return call_protected!(main(argc, argv, &instance)).map_err(|err| format!("{}", err));
         // TODO: We should implement emscripten __ATEXIT__
@@ -128,36 +128,53 @@ fn main() {
     }
 }
 
-fn get_module_arguments(options: &Run, instance: &mut webassembly::Instance) -> (u32, u32) {
-    // Application Arguments
-    let mut arg_values: Vec<String> = Vec::new();
-    let mut arg_addrs: Vec<*const u8> = Vec::new();
-    let arg_length = options.args.len() + 1;
+fn store_module_arguments(options: &Run, instance: &mut webassembly::Instance) -> (u32, u32) {
+    let argc = options.args.len() + 1;
 
-    arg_values.reserve_exact(arg_length);
-    arg_addrs.reserve_exact(arg_length);
+    let (argv_offset, argv_slice): (_, &mut [u32]) = unsafe { allocate_on_stack(((argc + 1) * 4) as u32, instance) };
+    assert!(argv_slice.len() >= 1);
 
-    // Push name of wasm file
-    arg_values.push(format!("{}\0", options.path.to_str().unwrap()));
-    arg_addrs.push(arg_values[0].as_ptr());
+    argv_slice[0] = unsafe { allocate_cstr_on_stack(options.path.to_str().unwrap(), instance).0 };
 
-    // Push additional arguments
-    for (i, arg) in options.args.iter().enumerate() {
-        arg_values.push(format!("{}\0", arg));
-        arg_addrs.push(arg_values[i + 1].as_ptr());
+    for (slot, arg) in argv_slice[1..argc].iter_mut().zip(options.args.iter()) {
+        *slot = unsafe { allocate_cstr_on_stack(&arg, instance).0 };
     }
 
-    // Get argument count and pointer to addresses
-    let argv = arg_addrs.as_ptr() as *mut *mut i8;
-    let argc = arg_length as u32;
+    argv_slice[argc] = 0;
 
-    // Copy the the arguments into the wasm memory and get offset
-    let argv_offset =  unsafe {
-        copy_cstr_array_into_wasm_stack(argc, argv, instance)
-    };
-
-    debug!("argc = {:?}", argc);
-    debug!("argv = {:?}", arg_addrs);
-
-    (argc, argv_offset)
+    (argc as u32, argv_offset)
 }
+
+// fn get_module_arguments(options: &Run, instance: &mut webassembly::Instance) -> (u32, u32) {
+//     // Application Arguments
+//     let mut arg_values: Vec<String> = Vec::new();
+//     let mut arg_addrs: Vec<*const u8> = Vec::new();
+//     let arg_length = options.args.len() + 1;
+
+//     arg_values.reserve_exact(arg_length);
+//     arg_addrs.reserve_exact(arg_length);
+
+//     // Push name of wasm file
+//     arg_values.push(format!("{}\0", options.path.to_str().unwrap()));
+//     arg_addrs.push(arg_values[0].as_ptr());
+
+//     // Push additional arguments
+//     for (i, arg) in options.args.iter().enumerate() {
+//         arg_values.push(format!("{}\0", arg));
+//         arg_addrs.push(arg_values[i + 1].as_ptr());
+//     }
+
+//     // Get argument count and pointer to addresses
+//     let argv = arg_addrs.as_ptr() as *mut *mut i8;
+//     let argc = arg_length as u32;
+
+//     // Copy the the arguments into the wasm memory and get offset
+//     let argv_offset =  unsafe {
+//         copy_cstr_array_into_wasm(argc, argv, instance)
+//     };
+
+//     debug!("argc = {:?}", argc);
+//     debug!("argv = {:?}", arg_addrs);
+
+//     (argc, argv_offset)
+// }

src/webassembly/instance.rs

@@ -74,7 +74,7 @@ pub struct EmscriptenData {
     pub free: extern "C" fn(i32, &mut Instance),
     pub memalign: extern "C" fn (u32, u32, &mut Instance) -> u32,
     pub memset: extern "C" fn(u32, i32, u32, &mut Instance) -> u32,
-    pub stack_alloc: extern "C" fn (u32, &mut Instance) -> u32,
+    pub stack_alloc: extern "C" fn (u32, &Instance) -> u32,
 }
 
 impl fmt::Debug for EmscriptenData {

src/webassembly/module.rs

@@ -9,7 +9,7 @@ use cranelift_codegen::cursor::FuncCursor;
 use cranelift_codegen::ir::immediates::{Imm64, Offset32};
 use cranelift_codegen::ir::types::*;
 use cranelift_codegen::ir::{
-    self, AbiParam, ArgumentPurpose, ExtFuncData, ExternalName, FuncRef, InstBuilder, Signature,
+    self, AbiParam, ArgumentPurpose, ExtFuncData, ExternalName, FuncRef, InstBuilder, Signature, TrapCode,
 };
 use cranelift_codegen::isa::{CallConv, TargetFrontendConfig};
 use cranelift_entity::{EntityRef, PrimaryMap};
@@ -532,6 +532,8 @@ impl<'environment> FuncEnvironmentTrait for FuncEnvironment<'environment> {
         mflags.set_aligned();
         let func_ptr = pos.ins().load(ptr, mflags, entry_addr, 0);
 
+        pos.ins().trapz(func_ptr, TrapCode::IndirectCallToNull);
+
         // Build a value list for the indirect call instruction containing the callee, call_args,
         // and the vmctx parameter.
         let mut args = ir::ValueList::default();