Make more code work with no_std. (#407)

* Make more code work with no_std.

no_std support is still incomplete, but this patch takes care of the
bulk of the straightforward parts.

wasmtime-environ/src/address_map.rs

@@ -1,11 +1,11 @@
 //! Data structures to provide transformation of the source
 // addresses of a WebAssembly module into the native code.
 
+use alloc::vec::Vec;
 use cranelift_codegen::ir;
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::DefinedFuncIndex;
 use serde::{Deserialize, Serialize};
-use std::vec::Vec;
 
 /// Single source location to generated address mapping.
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]

wasmtime-environ/src/cache.rs

@@ -2,6 +2,7 @@ use crate::address_map::{ModuleAddressMap, ValueLabelsRanges};
 use crate::compilation::{Compilation, Relocations, Traps};
 use crate::module::Module;
 use crate::module_environ::FunctionBodyData;
+use alloc::string::{String, ToString};
 use core::hash::Hasher;
 use cranelift_codegen::{ir, isa};
 use cranelift_entity::PrimaryMap;
@@ -13,7 +14,6 @@ use sha2::{Digest, Sha256};
 use std::fs;
 use std::io::Write;
 use std::path::{Path, PathBuf};
-use std::string::{String, ToString};
 
 #[macro_use] // for tests
 mod config;

wasmtime-environ/src/cache/config.rs

@@ -1,6 +1,9 @@
 //! Module for configuring the cache system.
 
 use super::worker;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
+use core::time::Duration;
 use directories::ProjectDirs;
 use lazy_static::lazy_static;
 use log::{debug, error, trace, warn};
@@ -13,10 +16,7 @@ use std::fmt::Debug;
 use std::fs;
 use std::mem;
 use std::path::{Path, PathBuf};
-use std::string::{String, ToString};
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::time::Duration;
-use std::vec::Vec;
 
 // wrapped, so we have named section in config,
 // also, for possible future compatibility

wasmtime-environ/src/cache/config/tests.rs

@@ -1,7 +1,7 @@
 use super::CacheConfig;
+use core::time::Duration;
 use std::fs;
 use std::path::PathBuf;
-use std::time::Duration;
 use tempfile::{self, TempDir};
 
 // note: config loading during validation creates cache directory to canonicalize its path,

wasmtime-environ/src/cache/tests.rs

@@ -3,17 +3,17 @@ use super::*;
 use crate::address_map::{FunctionAddressMap, InstructionAddressMap};
 use crate::compilation::{CodeAndJTOffsets, Relocation, RelocationTarget, TrapInformation};
 use crate::module::{MemoryPlan, MemoryStyle, Module};
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use core::cmp::min;
 use cranelift_codegen::{binemit, ir, isa, settings, ValueLocRange};
 use cranelift_entity::EntityRef;
 use cranelift_entity::{PrimaryMap, SecondaryMap};
 use cranelift_wasm::{DefinedFuncIndex, FuncIndex, Global, GlobalInit, Memory, SignatureIndex};
 use rand::rngs::SmallRng;
 use rand::{Rng, SeedableRng};
-use std::boxed::Box;
-use std::cmp::min;
 use std::fs;
 use std::str::FromStr;
-use std::vec::Vec;
 use target_lexicon::triple;
 
 // Since cache system is a global thing, each test needs to be run in seperate process.

wasmtime-environ/src/cache/worker.rs

@@ -6,10 +6,12 @@
 //! Background tasks can be CPU intensive, but the worker thread has low priority.
 
 use super::{cache_config, fs_write_atomic, CacheConfig};
+use alloc::vec::Vec;
+use core::cmp;
+use core::time::Duration;
 use log::{debug, info, trace, warn};
 use serde::{Deserialize, Serialize};
 use spin::Once;
-use std::cmp;
 use std::collections::HashMap;
 use std::ffi::OsStr;
 use std::fs;
@@ -19,10 +21,8 @@ use std::sync::mpsc::{sync_channel, Receiver, SyncSender};
 #[cfg(test)]
 use std::sync::{Arc, Condvar, Mutex};
 use std::thread;
-use std::time::Duration;
 #[cfg(not(test))]
 use std::time::SystemTime;
-use std::vec::Vec;
 #[cfg(test)]
 use tests::system_time_stub::SystemTimeStub as SystemTime;
 

wasmtime-environ/src/cache/worker/tests.rs

@@ -1,6 +1,6 @@
 use super::*;
 use crate::cache::config::tests::test_prolog;
-use std::iter::repeat;
+use core::iter::repeat;
 use std::process;
 // load_config! comes from crate::cache(::config::tests);
 

wasmtime-environ/src/compilation.rs

@@ -4,12 +4,12 @@
 use crate::address_map::{ModuleAddressMap, ValueLabelsRanges};
 use crate::module;
 use crate::module_environ::FunctionBodyData;
+use alloc::vec::Vec;
 use cranelift_codegen::{binemit, ir, isa, CodegenError};
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::{DefinedFuncIndex, FuncIndex, WasmError};
 use serde::{Deserialize, Serialize};
 use std::ops::Range;
-use std::vec::Vec;
 
 /// Compiled machine code: body and jump table offsets.
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]

wasmtime-environ/src/cranelift.rs

@@ -14,6 +14,7 @@ use crate::func_environ::{
 };
 use crate::module::Module;
 use crate::module_environ::FunctionBodyData;
+use alloc::vec::Vec;
 use cranelift_codegen::binemit;
 use cranelift_codegen::ir;
 use cranelift_codegen::ir::ExternalName;
@@ -22,7 +23,6 @@ use cranelift_codegen::Context;
 use cranelift_entity::PrimaryMap;
 use cranelift_wasm::{DefinedFuncIndex, FuncIndex, FuncTranslator};
 use rayon::prelude::{IntoParallelRefIterator, ParallelIterator};
-use std::vec::Vec;
 
 /// Implementation of a relocation sink that just saves all the information for later
 pub struct RelocSink {

wasmtime-environ/src/func_environ.rs

@@ -1,6 +1,7 @@
 use crate::module::{MemoryPlan, MemoryStyle, Module, TableStyle};
 use crate::vmoffsets::VMOffsets;
 use crate::WASM_PAGE_SIZE;
+use alloc::vec::Vec;
 use core::clone::Clone;
 use core::convert::TryFrom;
 use cranelift_codegen::cursor::FuncCursor;
@@ -17,7 +18,6 @@ use cranelift_wasm::{
 };
 #[cfg(feature = "lightbeam")]
 use cranelift_wasm::{DefinedFuncIndex, DefinedGlobalIndex, DefinedMemoryIndex, DefinedTableIndex};
-use std::vec::Vec;
 
 /// Compute an `ir::ExternalName` for a given wasm function index.
 pub fn get_func_name(func_index: FuncIndex) -> ir::ExternalName {

wasmtime-environ/src/lib.rs

@@ -24,14 +24,8 @@
         clippy::use_self
     )
 )]
-#![no_std]
 
-#[cfg(not(feature = "std"))]
-#[macro_use]
-extern crate alloc as std;
-#[cfg(feature = "std")]
-#[macro_use]
-extern crate std;
+extern crate alloc;
 
 #[macro_use]
 extern crate failure_derive;

wasmtime-environ/src/module.rs

@@ -2,6 +2,9 @@
 
 use crate::module_environ::FunctionBodyData;
 use crate::tunables::Tunables;
+use alloc::boxed::Box;
+use alloc::string::String;
+use alloc::vec::Vec;
 use core::hash::{Hash, Hasher};
 use cranelift_codegen::ir;
 use cranelift_entity::{EntityRef, PrimaryMap};
@@ -10,9 +13,6 @@ use cranelift_wasm::{
     GlobalIndex, Memory, MemoryIndex, SignatureIndex, Table, TableIndex,
 };
 use indexmap::IndexMap;
-use std::boxed::Box;
-use std::string::String;
-use std::vec::Vec;
 
 /// A WebAssembly table initializer.
 #[derive(Clone, Debug, Hash)]

wasmtime-environ/src/module_environ.rs

@@ -1,6 +1,9 @@
 use crate::func_environ::FuncEnvironment;
 use crate::module::{Export, MemoryPlan, Module, TableElements, TablePlan};
 use crate::tunables::Tunables;
+use alloc::boxed::Box;
+use alloc::string::String;
+use alloc::vec::Vec;
 use core::convert::TryFrom;
 use cranelift_codegen::ir;
 use cranelift_codegen::ir::{AbiParam, ArgumentPurpose};
@@ -10,9 +13,6 @@ use cranelift_wasm::{
     self, translate_module, DefinedFuncIndex, FuncIndex, Global, GlobalIndex, Memory, MemoryIndex,
     SignatureIndex, Table, TableIndex, WasmResult,
 };
-use std::boxed::Box;
-use std::string::String;
-use std::vec::Vec;
 
 /// Contains function data: byte code and its offset in the module.
 #[derive(Hash)]