From 821c76e3f773a19a9a11dfd333f6c88fd1de8987 Mon Sep 17 00:00:00 2001 From: Jan Bujak Date: Wed, 8 Nov 2023 07:05:56 +0000 Subject: [PATCH] Also build the standard library crates when building the runtimes --- substrate/utils/wasm-builder/src/lib.rs | 30 +++++++++++++++++++ .../utils/wasm-builder/src/wasm_project.rs | 20 +++++++++++++ 2 files changed, 50 insertions(+) diff --git a/substrate/utils/wasm-builder/src/lib.rs b/substrate/utils/wasm-builder/src/lib.rs index c9011f97be71..ff7dbc1ef227 100644 --- a/substrate/utils/wasm-builder/src/lib.rs +++ b/substrate/utils/wasm-builder/src/lib.rs @@ -87,6 +87,9 @@ //! required as we walk up from the target directory until we find a `Cargo.toml`. If the target //! directory is changed for the build, this environment variable can be used to point to the //! actual workspace. +//! - `WASM_BUILD_STD` - Sets whether the Rust's standard library crates will also be built. This is +//! necessary to make sure the standard library crates only use the exact WASM feature set that +//! our executor supports. Enabled by default. //! - `CARGO_NET_OFFLINE` - If `true`, `--offline` will be passed to all processes launched to //! prevent network access. Useful in offline environments. //! @@ -158,6 +161,9 @@ const FORCE_WASM_BUILD_ENV: &str = "FORCE_WASM_BUILD"; /// Environment variable that hints the workspace we are building. const WASM_BUILD_WORKSPACE_HINT: &str = "WASM_BUILD_WORKSPACE_HINT"; +/// Environment variable to set whether we'll build `core`/`std`. +const WASM_BUILD_STD: &str = "WASM_BUILD_STD"; + /// Write to the given `file` if the `content` is different. fn write_file_if_changed(file: impl AsRef, content: impl AsRef) { if fs::read_to_string(file.as_ref()).ok().as_deref() != Some(content.as_ref()) { @@ -282,6 +288,12 @@ impl CargoCommand { self.version } + /// Returns whether this version of the toolchain supports nightly features. + fn supports_nightly_features(&self) -> bool { + self.version.map(|version| version.is_nightly).unwrap_or(false) || + env::var("RUSTC_BOOTSTRAP").is_ok() + } + /// Check if the supplied cargo command supports our Substrate wasm environment. /// /// This means that either the cargo version is at minimum 1.68.0 or this is a nightly cargo. @@ -332,3 +344,21 @@ impl std::ops::Deref for CargoCommandVersioned { fn color_output_enabled() -> bool { env::var(crate::WASM_BUILD_NO_COLOR).is_err() } + +/// Fetches a boolean environment variable. Will exit the process if the value is invalid. +fn get_bool_environment_variable(name: &str) -> Option { + let value = env::var_os(name)?; + + // We're comparing `OsString`s here so we can't use a `match`. + if value == "1" { + Some(true) + } else if value == "0" { + Some(false) + } else { + build_helper::warning!( + "the '{}' environment variable has an invalid value; it must be either '1' or '0'", + name + ); + std::process::exit(1); + } +} diff --git a/substrate/utils/wasm-builder/src/wasm_project.rs b/substrate/utils/wasm-builder/src/wasm_project.rs index 849af853c6da..d6886bb8ba48 100644 --- a/substrate/utils/wasm-builder/src/wasm_project.rs +++ b/substrate/utils/wasm-builder/src/wasm_project.rs @@ -693,6 +693,25 @@ fn build_project( build_cmd.arg("--offline"); } + // Our executor currently only supports the WASM MVP feature set, however nowadays + // when compiling WASM the Rust compiler has more features enabled by default. + // + // We do set the `-C target-cpu=mvp` flag to make sure that *our* code gets compiled + // in a way that is compatible with our executor, however this doesn't affect Rust's + // standard library crates (`std`, `core` and `alloc`) which are by default precompiled + // and still can make use of these extra features. + // + // So here we force the compiler to also compile the standard library crates for us + // to make sure that they also only use the MVP features. + if crate::get_bool_environment_variable(crate::WASM_BUILD_STD).unwrap_or(true) { + // Unfortunately this is still a nightly-only flag, but FWIW it is pretty widely used + // so it's unlikely to break without a replacement. + build_cmd.arg("-Z").arg("build-std"); + if !cargo_cmd.supports_nightly_features() { + build_cmd.env("RUSTC_BOOTSTRAP", "1"); + } + } + println!("{}", colorize_info_message("Information that should be included in a bug report.")); println!("{} {:?}", colorize_info_message("Executing build command:"), build_cmd); println!("{} {}", colorize_info_message("Using rustc version:"), cargo_cmd.rustc_version()); @@ -877,6 +896,7 @@ fn generate_rerun_if_changed_instructions( println!("cargo:rerun-if-env-changed={}", crate::WASM_BUILD_RUSTFLAGS_ENV); println!("cargo:rerun-if-env-changed={}", crate::WASM_TARGET_DIRECTORY); println!("cargo:rerun-if-env-changed={}", crate::WASM_BUILD_TOOLCHAIN); + println!("cargo:rerun-if-env-changed={}", crate::WASM_BUILD_STD); } /// Track files and paths related to the given package to rerun `build.rs` on any relevant change.