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// Copyright 2018-2020 Parity Technologies (UK) Ltd.
// This file is part of cargo-contract.
// cargo-contract is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// cargo-contract is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with cargo-contract. If not, see <http://www.gnu.org/licenses/>.
use std::{
fs::metadata,
io::{self, Write},
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use crate::{
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util,
workspace::{ManifestPath, Profile, Workspace},
UnstableFlags, Verbosity,
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};
use anyhow::{Context, Result};
use parity_wasm::elements::{External, MemoryType, Module, Section};
/// This is the maximum number of pages available for a contract to allocate.
const MAX_MEMORY_PAGES: u32 = 16;
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/// Builds the project in the specified directory, defaults to the current directory.
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/// Uses [`cargo-xbuild`](https://github.com/rust-osdev/cargo-xbuild) for maximum optimization of
/// the resulting Wasm binary.
///
/// # Cargo.toml optimizations
///
/// The original Cargo.toml will be amended to remove the `rlib` crate type in order to minimize
/// the final Wasm binary size.
///
/// Preferred default `[profile.release]` settings will be added if they are missing, existing
/// user-defined settings will be preserved.
///
/// To disable this and use the original `Cargo.toml` as is then pass the `-Z original_manifest` flag.
fn build_cargo_project(
crate_metadata: &CrateMetadata,
verbosity: Option<Verbosity>,
unstable_options: UnstableFlags,
) -> Result<()> {
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util::assert_channel()?;
// set RUSTFLAGS, read from environment var by cargo-xbuild
std::env::set_var(
"RUSTFLAGS",
"-C link-arg=-z -C link-arg=stack-size=65536 -C link-arg=--import-memory",
);
let verbosity = verbosity.map(|v| match v {
Verbosity::Verbose => xargo_lib::Verbosity::Verbose,
Verbosity::Quiet => xargo_lib::Verbosity::Quiet,
});
let xbuild = |manifest_path: &ManifestPath| {
let manifest_path = Some(manifest_path);
let target = Some("wasm32-unknown-unknown");
let target_dir = &crate_metadata.cargo_meta.target_directory;
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let other_args = [
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&format!("--target-dir={}", target_dir.to_string_lossy()),
];
let args = xargo_lib::Args::new(target, manifest_path, verbosity, &other_args)
.map_err(|e| anyhow::anyhow!("{}", e))
.context("Creating xargo args")?;
let config = xargo_lib::Config {
sysroot_path: target_dir.join("sysroot"),
memcpy: false,
panic_immediate_abort: true,
};
let exit_status = xargo_lib::build(args, "build", Some(config))
.map_err(|e| anyhow::anyhow!("{}", e))
.context("Building with xbuild")?;
if !exit_status.success() {
anyhow::bail!("xbuild failed with status {}", exit_status)
}
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Ok(())
};
if unstable_options.original_manifest {
println!(
"{} {}",
"warning:".yellow().bold(),
"with 'original-manifest' enabled, the contract binary may not be of optimal size."
.bold()
);
xbuild(&crate_metadata.manifest_path)?;
} else {
Workspace::new(&crate_metadata.cargo_meta, &crate_metadata.root_package.id)?
.with_root_package_manifest(|manifest| {
manifest
.with_removed_crate_type("rlib")?
.with_profile_release_defaults(Profile::default_contract_release())?;
Ok(())
})?
.using_temp(xbuild)?;
}
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// clear RUSTFLAGS
std::env::remove_var("RUSTFLAGS");
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Ok(())
}
/// Ensures the wasm memory import of a given module has the maximum number of pages.
///
/// Iterates over the import section, finds the memory import entry if any and adjusts the maximum
/// limit.
fn ensure_maximum_memory_pages(module: &mut Module, maximum_allowed_pages: u32) -> Result<()> {
let mem_ty = module
.import_section_mut()
.and_then(|section| {
.find_map(|entry| match entry.external_mut() {
External::Memory(ref mut mem_ty) => Some(mem_ty),
_ => None,
.context("Memory import is not found. Is --import-memory specified in the linker args")?;
if let Some(requested_maximum) = mem_ty.limits().maximum() {
// The module already has maximum, check if it is within the limit bail out.
if requested_maximum > maximum_allowed_pages {
anyhow::bail!(
"The wasm module requires {} pages. The maximum allowed number of pages is {}",
requested_maximum,
maximum_allowed_pages,
);
}
} else {
let initial = mem_ty.limits().initial();
*mem_ty = MemoryType::new(initial, Some(MAX_MEMORY_PAGES));
}
Ok(())
}
/// Strips all custom sections.
///
/// Presently all custom sections are not required so they can be stripped safely.
fn strip_custom_sections(module: &mut Module) {
module.sections_mut().retain(|section| match section {
Section::Custom(_) => false,
Section::Name(_) => false,
Section::Reloc(_) => false,
_ => true,
});
}
/// Performs required post-processing steps on the wasm artifact.
fn post_process_wasm(crate_metadata: &CrateMetadata) -> Result<()> {
// Deserialize wasm module from a file.
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let mut module =
parity_wasm::deserialize_file(&crate_metadata.original_wasm).context(format!(
"Loading original wasm file '{}'",
crate_metadata.original_wasm.display()
))?;
// Perform optimization.
//
// In practice only tree-shaking is performed, i.e transitively removing all symbols that are
// NOT used by the specified entrypoints.
if pwasm_utils::optimize(&mut module, ["call", "deploy"].to_vec()).is_err() {
anyhow::bail!("Optimizer failed");
}
ensure_maximum_memory_pages(&mut module, MAX_MEMORY_PAGES)?;
strip_custom_sections(&mut module);
parity_wasm::serialize_to_file(&crate_metadata.dest_wasm, module)?;
Ok(())
}
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/// Attempts to perform optional wasm optimization using `wasm-opt`.
///
/// The intention is to reduce the size of bloated wasm binaries as a result of missing
/// optimizations (or bugs?) between Rust and Wasm.
///
/// This step depends on the `wasm-opt` tool being installed. If it is not the build will still
/// succeed, and the user will be encouraged to install it for further optimizations.
fn optimize_wasm(crate_metadata: &CrateMetadata) -> Result<()> {
// check `wasm-opt` installed
if which::which("wasm-opt").is_err() {
println!(
"{}",
"wasm-opt is not installed. Install this tool on your system in order to \n\
reduce the size of your contract's Wasm binary. \n\
See https://github.com/WebAssembly/binaryen#tools"
.bright_yellow()
);
return Ok(());
}
let mut optimized = crate_metadata.dest_wasm.clone();
optimized.set_file_name(format!("{}-opt.wasm", crate_metadata.package_name));
let output = Command::new("wasm-opt")
.arg(crate_metadata.dest_wasm.as_os_str())
.arg("-O3") // execute -O3 optimization passes (spends potentially a lot of time optimizing)
.arg("-o")
.arg(optimized.as_os_str())
.output()?;
if !output.status.success() {
// Dump the output streams produced by wasm-opt into the stdout/stderr.
io::stdout().write_all(&output.stdout)?;
io::stderr().write_all(&output.stderr)?;
anyhow::bail!("wasm-opt optimization failed");
}
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let original_size = metadata(&crate_metadata.dest_wasm)?.len() as f64 / 1000.0;
let optimized_size = metadata(&optimized)?.len() as f64 / 1000.0;
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" Original wasm size: {:.1}K, Optimized: {:.1}K",
original_size, optimized_size
);
// overwrite existing destination wasm file with the optimised version
std::fs::rename(&optimized, &crate_metadata.dest_wasm)?;
Ok(())
}
/// Executes build of the smart-contract which produces a wasm binary that is ready for deploying.
///
/// It does so by invoking `cargo build` and then post processing the final binary.
///
/// # Note
///
/// Collects the contract crate's metadata using the supplied manifest (`Cargo.toml`) path. Use
/// [`execute_build_with_metadata`] if an instance is already available.
pub(crate) fn execute(
manifest_path: &ManifestPath,
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verbosity: Option<Verbosity>,
unstable_options: UnstableFlags,
) -> Result<PathBuf> {
let crate_metadata = CrateMetadata::collect(manifest_path)?;
execute_with_metadata(&crate_metadata, verbosity, unstable_options)
}
/// Executes build of the smart-contract which produces a wasm binary that is ready for deploying.
///
/// It does so by invoking `cargo build` and then post processing the final binary.
///
/// # Note
///
/// Uses the supplied `CrateMetadata`. If an instance is not available use [`execute_build`]
pub(crate) fn execute_with_metadata(
crate_metadata: &CrateMetadata,
verbosity: Option<Verbosity>,
unstable_options: UnstableFlags,
) -> Result<PathBuf> {
"Building cargo project".bright_green().bold()
);
build_cargo_project(&crate_metadata, verbosity, unstable_options)?;
"Post processing wasm file".bright_green().bold()
);
post_process_wasm(&crate_metadata)?;
"Optimizing wasm file".bright_green().bold()
);
optimize_wasm(&crate_metadata)?;
Ok(crate_metadata.dest_wasm.clone())
#[cfg(feature = "test-ci-only")]
use crate::{cmd, util::tests::with_tmp_dir, ManifestPath, UnstableFlags};
#[test]
fn build_template() {
with_tmp_dir(|path| {
cmd::new::execute("new_project", Some(path)).expect("new project creation failed");
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let manifest_path =
ManifestPath::new(&path.join("new_project").join("Cargo.toml")).unwrap();
super::execute(&manifest_path, None, UnstableFlags::default()).expect("build failed");
Ok(())
})