Upgrade libm and make no-std config testable (#241)

* Make everything build and test without 'std' feature

Signed-off-by: Brian Anderson <[email protected]>

* Use faster constructor in vec_bytebuf.

`vec![0; len]` uses a specialized intrinsic codepath, which, at least in debug
mode, is extremely faster than `resize`.

This makes the `alloc` test pass instantaneously instead of taking minutes.

Signed-off-by: Brian Anderson <[email protected]>

* Fix a comment about core+mmap

Signed-off-by: Brian Anderson <[email protected]>

* Don't use traits to call libm functions

These no longer exist in the latest revision of libm.

Signed-off-by: Brian Anderson <[email protected]>

* Upgrade libm to 0.2.1

Fixes #240

Signed-off-by: Brian Anderson <[email protected]>

* Remove warning from readme about debug-mode panics from libm

Signed-off-by: Brian Anderson <[email protected]>

* Test no-std configuration under travis

Signed-off-by: Brian Anderson <[email protected]>

* rustfmt

Signed-off-by: Brian Anderson <[email protected]>

Author: brson

.travis.yml

@@ -30,6 +30,7 @@ script:
 # Check that `vec_memory` feature works.
 - cargo check --features vec_memory
 - travis_wait 60 ./test.sh
+- TEST_NO_STD=1 travis_wait 60 ./test.sh
 - ./doc.sh
 
 after_success: |

Cargo.toml

@@ -15,7 +15,7 @@ exclude = [ "/res/*", "/tests/*", "/fuzz/*", "/benches/*" ]
 validation = { package = "wasmi-validation", version = "0.3", path = "validation", default-features = false }
 parity-wasm = { version = "0.41.0", default-features = false }
 memory_units = "0.3.0"
-libm = { version = "0.1.2", optional = true }
+libm = { version = "0.2.1", optional = true }
 num-rational = { version = "0.2.2", default-features = false }
 num-traits = { version = "0.2.8", default-features = false }
 libc = { version = "0.2.58", optional = true}
@@ -41,7 +41,7 @@ std = [
 ]
 # Enable for no_std support
 core = [
-    # `core` doesn't support vec_memory
+    # `core` doesn't support mmaped memory
     "vec_memory",
     "validation/core",
     "libm"

README.md

@@ -35,9 +35,6 @@ wasmi = {
 
 When the `core` feature is enabled, code related to `std::error` is disabled.
 
-Floating point operations in `no_std` use [`libm`](https://crates.io/crates/libm), which sometimes panics in debug mode (https://github.com/japaric/libm/issues/4).
-So make sure to either use release builds or avoid WASM with floating point operations, for example by using [`deny_floating_point`](https://docs.rs/wasmi/0.4.0/wasmi/struct.Module.html#method.deny_floating_point).
-
 # License
 
 `wasmi` is primarily distributed under the terms of both the MIT

examples/invoke.rs

@@ -3,7 +3,7 @@ extern crate wasmi;
 
 use std::env::args;
 
-use parity_wasm::elements::{External, FunctionType, Internal, Type, ValueType};
+use parity_wasm::elements::{External, FunctionType, Internal, Module, Type, ValueType};
 use wasmi::{ImportsBuilder, ModuleInstance, NopExternals, RuntimeValue};
 
 fn main() {
@@ -15,7 +15,7 @@ fn main() {
     let func_name = &args[2];
     let (_, program_args) = args.split_at(3);
 
-    let module = parity_wasm::deserialize_file(&args[1]).expect("File to be deserialized");
+    let module = load_module(&args[1]);
 
     // Extracts call arguments from command-line arguments
     let args = {
@@ -118,3 +118,14 @@ fn main() {
             .expect("")
     );
 }
+
+#[cfg(feature = "std")]
+fn load_module(file: &str) -> Module {
+    parity_wasm::deserialize_file(file).expect("File to be deserialized")
+}
+
+#[cfg(not(feature = "std"))]
+fn load_module(file: &str) -> Module {
+    let mut buf = std::fs::read(file).expect("Read file");
+    parity_wasm::deserialize_buffer(&mut buf).expect("Deserialize module")
+}

src/memory/mod.rs

@@ -542,7 +542,7 @@ mod tests {
     use super::{MemoryInstance, MemoryRef, LINEAR_MEMORY_PAGE_SIZE};
     use crate::memory_units::Pages;
     use crate::Error;
-    use std::rc::Rc;
+    use alloc::rc::Rc;
 
     #[test]
     fn alloc() {

src/memory/vec_bytebuf.rs

@@ -8,8 +8,7 @@ pub struct ByteBuf {
 
 impl ByteBuf {
     pub fn new(len: usize) -> Result<Self, String> {
-        let mut buf = Vec::new();
-        buf.resize(len, 0u8);
+        let buf = vec![0; len];
         Ok(Self { buf })
     }
 

src/prepare/tests.rs

@@ -1,3 +1,9 @@
+// Test-only code importing std for no-std testing
+extern crate std;
+
+use alloc::vec::Vec;
+use std::println;
+
 use super::{compile_module, CompiledModule};
 use crate::isa;
 use parity_wasm::{deserialize_buffer, elements::Module};

src/tests/host.rs

@@ -1,3 +1,6 @@
+// Test-only code importing std for no-std testing
+extern crate std;
+
 use super::parse_wat;
 use crate::memory_units::Pages;
 use crate::types::ValueType;
@@ -6,6 +9,8 @@ use crate::{
     MemoryInstance, MemoryRef, ModuleImportResolver, ModuleInstance, ModuleRef, ResumableError,
     RuntimeArgs, RuntimeValue, Signature, TableDescriptor, TableInstance, TableRef, Trap, TrapKind,
 };
+use alloc::boxed::Box;
+use std::println;
 
 #[derive(Debug, Clone, PartialEq)]
 struct HostErrorWithCode {

src/tests/mod.rs

@@ -8,7 +8,10 @@ use super::Error;
 
 fn assert_send<T: Send>() {}
 fn assert_sync<T: Sync>() {}
+#[cfg(feature = "std")]
 fn assert_std_err_impl<T: ::std::error::Error>() {}
+#[cfg(not(feature = "std"))]
+fn assert_std_err_impl<T>() {}
 
 #[test]
 fn assert_error_properties() {

src/tests/wasm.rs

@@ -1,9 +1,13 @@
+// Test-only code importing std for no-std testing
+extern crate std;
+
 use crate::memory_units::Pages;
 use crate::{
     Error, FuncRef, GlobalDescriptor, GlobalInstance, GlobalRef, ImportsBuilder, MemoryDescriptor,
     MemoryInstance, MemoryRef, Module, ModuleImportResolver, ModuleInstance, NopExternals,
     RuntimeValue, Signature, TableDescriptor, TableInstance, TableRef,
 };
+use alloc::vec::Vec;
 use std::fs::File;
 
 struct Env {

src/value.rs

@@ -828,48 +828,42 @@ impl_integer!(u32);
 impl_integer!(i64);
 impl_integer!(u64);
 
-// Use std float functions in std environment.
-// And libm's implementation in no_std
 #[cfg(feature = "std")]
-macro_rules! call_math {
-    ($op:ident, $e:expr, $fXX:ident, $FXXExt:ident) => {
-        $fXX::$op($e)
-    };
+mod fmath {
+    pub use f32;
+    pub use f64;
 }
+
 #[cfg(not(feature = "std"))]
-macro_rules! call_math {
-    ($op:ident, $e:expr, $fXX:ident, $FXXExt:ident) => {
-        ::libm::$FXXExt::$op($e)
-    };
+mod fmath {
+    pub use super::libm_adapters::f32;
+    pub use super::libm_adapters::f64;
 }
 
-// We cannot call the math functions directly, because there are multiple available implementaitons in no_std.
-// In std, there are only `Value::$op` and `std::$fXX:$op`.
-// The `std` ones are preferred, because they are not from a trait.
-// For `no_std`, the implementations are `Value::$op` and `libm::FXXExt::$op`,
-// both of which are trait implementations and hence ambiguous.
-// So we have to use a full path, which is what `call_math!` does.
+// We cannot call the math functions directly, because they are not all available in `core`.
+// In no-std cases we instead rely on `libm`.
+// These wrappers handle that delegation.
 macro_rules! impl_float {
-    ($type:ident, $fXX:ident, $FXXExt:ident, $iXX:ident) => {
+    ($type:ident, $fXX:ident, $iXX:ident) => {
         impl Float<$type> for $type {
             fn abs(self) -> $type {
-                call_math!(abs, $fXX::from(self), $fXX, $FXXExt).into()
+                fmath::$fXX::abs($fXX::from(self)).into()
             }
             fn floor(self) -> $type {
-                call_math!(floor, $fXX::from(self), $fXX, $FXXExt).into()
+                fmath::$fXX::floor($fXX::from(self)).into()
             }
             fn ceil(self) -> $type {
-                call_math!(ceil, $fXX::from(self), $fXX, $FXXExt).into()
+                fmath::$fXX::ceil($fXX::from(self)).into()
             }
             fn trunc(self) -> $type {
-                call_math!(trunc, $fXX::from(self), $fXX, $FXXExt).into()
+                fmath::$fXX::trunc($fXX::from(self)).into()
             }
             fn round(self) -> $type {
-                call_math!(round, $fXX::from(self), $fXX, $FXXExt).into()
+                fmath::$fXX::round($fXX::from(self)).into()
             }
             fn nearest(self) -> $type {
                 let round = self.round();
-                if call_math!(fract, $fXX::from(self), $fXX, $FXXExt).abs() != 0.5 {
+                if fmath::$fXX::fract($fXX::from(self)).abs() != 0.5 {
                     return round;
                 }
 
@@ -883,7 +877,7 @@ macro_rules! impl_float {
                 }
             }
             fn sqrt(self) -> $type {
-                call_math!(sqrt, $fXX::from(self), $fXX, $FXXExt).into()
+                fmath::$fXX::sqrt($fXX::from(self)).into()
             }
             // This instruction corresponds to what is sometimes called "minNaN" in other languages.
             fn min(self, other: $type) -> $type {
@@ -931,7 +925,70 @@ macro_rules! impl_float {
     };
 }
 
-impl_float!(f32, f32, F32Ext, i32);
-impl_float!(f64, f64, F64Ext, i64);
-impl_float!(F32, f32, F32Ext, i32);
-impl_float!(F64, f64, F64Ext, i64);
+impl_float!(f32, f32, i32);
+impl_float!(f64, f64, i64);
+impl_float!(F32, f32, i32);
+impl_float!(F64, f64, i64);
+
+#[cfg(not(feature = "std"))]
+mod libm_adapters {
+    pub mod f32 {
+        pub fn abs(v: f32) -> f32 {
+            libm::fabsf(v)
+        }
+
+        pub fn floor(v: f32) -> f32 {
+            libm::floorf(v)
+        }
+
+        pub fn ceil(v: f32) -> f32 {
+            libm::ceilf(v)
+        }
+
+        pub fn trunc(v: f32) -> f32 {
+            libm::truncf(v)
+        }
+
+        pub fn round(v: f32) -> f32 {
+            libm::roundf(v)
+        }
+
+        pub fn fract(v: f32) -> f32 {
+            v - trunc(v)
+        }
+
+        pub fn sqrt(v: f32) -> f32 {
+            libm::sqrtf(v)
+        }
+    }
+
+    pub mod f64 {
+        pub fn abs(v: f64) -> f64 {
+            libm::fabs(v)
+        }
+
+        pub fn floor(v: f64) -> f64 {
+            libm::floor(v)
+        }
+
+        pub fn ceil(v: f64) -> f64 {
+            libm::ceil(v)
+        }
+
+        pub fn trunc(v: f64) -> f64 {
+            libm::trunc(v)
+        }
+
+        pub fn round(v: f64) -> f64 {
+            libm::round(v)
+        }
+
+        pub fn fract(v: f64) -> f64 {
+            v - trunc(v)
+        }
+
+        pub fn sqrt(v: f64) -> f64 {
+            libm::sqrt(v)
+        }
+    }
+}

test.sh

@@ -3,6 +3,7 @@
 set -eux
 
 EXTRA_ARGS=""
+NO_STD_ARGS=""
 
 if [ -n "${TARGET-}" ]; then
     # Tests build in debug mode are prohibitively
@@ -12,8 +13,12 @@ if [ -n "${TARGET-}" ]; then
     export RUSTFLAGS="--cfg debug_assertions"
 fi
 
+if [ -n "${TEST_NO_STD-}" ]; then
+    NO_STD_ARGS="--no-default-features --features=core"
+fi
+
 cd $(dirname $0)
 
-time cargo test --all ${EXTRA_ARGS}
+time cargo test --all ${EXTRA_ARGS} ${NO_STD_ARGS}
 
 cd -