Updating target json support

Cargo.toml

@@ -19,6 +19,7 @@ members = [
 
     "crates/rustc_codegen_spirv",
     "crates/rustc_codegen_spirv-types",
+    "crates/rustc_codegen_spirv_target_specs",
     "crates/spirv-builder",
     "crates/spirv-std",
     "crates/spirv-std/shared",
@@ -46,6 +47,7 @@ spirv-std-macros = { path = "./crates/spirv-std/macros", version = "=0.9.0" }
 spirv-tools = { version = "0.11", default-features = false }
 rustc_codegen_spirv = { path = "./crates/rustc_codegen_spirv", version = "=0.9.0", default-features = false }
 rustc_codegen_spirv-types = { path = "./crates/rustc_codegen_spirv-types", version = "=0.9.0" }
+rustc_codegen_spirv_target_specs = { path = "./crates/rustc_codegen_spirv_target_specs", version = "=0.9.0" }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3.3", features = ["env-filter", "json"] }
 

crates/rustc_codegen_spirv/Cargo.toml

@@ -61,6 +61,9 @@ tracing.workspace = true
 tracing-subscriber.workspace = true
 tracing-tree = "0.3.0"
 
+# required for cargo gpu to resolve the needed target specs
+rustc_codegen_spirv_target_specs.workspace = true
+
 [dev-dependencies]
 pretty_assertions = "1.0"
 

crates/rustc_codegen_spirv_target_specs/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "rustc_codegen_spirv_target_specs"
+description = "target spec json files of rust-gpu for the rustc compiler"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+
+[features]
+include_str = []
+dir_path = []

crates/rustc_codegen_spirv_target_specs/README.md

@@ -0,0 +1,7 @@
+# `rustc_codegen_spirv_target_spec`
+
+The target spec json files of rust-gpu to hand to the rustc compiler, declaring various metadata about our codegen backend.
+
+## Features
+* `include_str`: include target specs as string constants, for bundling with `cargo-gpu`
+* `dir_path`: export a path to the target specs dir, for `spirv-builder` and `compiletest` in this repo

crates/rustc_codegen_spirv_target_specs/src/lib.rs

@@ -0,0 +1,10 @@
+#![doc = include_str!("../README.md")]
+
+/// directory with all the `target-specs` jsons for our codegen backend
+#[cfg(feature = "dir_path")]
+pub const TARGET_SPEC_DIR_PATH: &str = concat!(env!("CARGO_MANIFEST_DIR"), "/target-specs");
+
+#[cfg(feature = "include_str")]
+mod include_str;
+#[cfg(feature = "include_str")]
+pub use include_str::TARGET_SPECS;

crates/spirv-builder/Cargo.toml

@@ -22,21 +22,23 @@ default = ["use-compiled-tools"]
 # Compile `rustc_codegen_spirv`, allows constructing SpirvBuilder without
 # explicitly passing in a path to a compiled `rustc_codegen_spirv.so` (or dll)
 rustc_codegen_spirv = ["dep:rustc_codegen_spirv"]
+# Inclide target spec json files, allows constructing SpirvBuilder without
+# explicitly passing a path to the target spec json
+include_target_specs = ["dep:rustc_codegen_spirv_target_specs"]
 # See `rustc_codegen_spirv/Cargo.toml` for details on these features.
-use-installed-tools = ["rustc_codegen_spirv", "rustc_codegen_spirv?/use-installed-tools"]
-use-compiled-tools = ["rustc_codegen_spirv", "rustc_codegen_spirv?/use-compiled-tools"]
+# We add new "default" features to `use-installed-tools` and `use-compiled-tools` to keep
+# backwards compat with `default-features = false, features = "use-installed-tools"` setups
+use-installed-tools = ["rustc_codegen_spirv", "include_target_specs", "rustc_codegen_spirv?/use-installed-tools"]
+use-compiled-tools = ["rustc_codegen_spirv", "include_target_specs", "rustc_codegen_spirv?/use-compiled-tools"]
 skip-toolchain-check = ["rustc_codegen_spirv?/skip-toolchain-check"]
 
 watch = ["dep:notify"]
 clap = ["dep:clap"]
 
 [dependencies]
-# See comment in `src/lib.rs` `invoke_rustc` regarding `rustc_codegen_spirv` dep.
-rustc_codegen_spirv.workspace = true
-# HACK(eddyb) see `docs.rs`-related comment above for why this is optional.
-rustc_codegen_spirv.optional = true
-
-rustc_codegen_spirv-types.workspace = true
+rustc_codegen_spirv = { workspace = true, optional = true }
+rustc_codegen_spirv-types = { workspace = true }
+rustc_codegen_spirv_target_specs = { workspace = true, features = ["dir_path"], optional = true }
 
 memchr = "2.4"
 raw-string = "0.3.5"

crates/spirv-builder/src/lib.rs

@@ -73,7 +73,6 @@
 #![doc = include_str!("../README.md")]
 
 mod depfile;
-mod target_specs;
 #[cfg(feature = "watch")]
 mod watch;
 
@@ -91,7 +90,9 @@ use thiserror::Error;
 
 pub use rustc_codegen_spirv_types::Capability;
 pub use rustc_codegen_spirv_types::{CompileResult, ModuleResult};
-pub use target_specs::TARGET_SPECS;
+
+#[cfg(feature = "include_target_specs")]
+pub use rustc_codegen_spirv_target_specs::TARGET_SPEC_DIR_PATH;
 
 #[derive(Debug, Error)]
 #[non_exhaustive]
@@ -107,11 +108,16 @@ pub enum SpirvBuilderError {
     #[error("crate path '{0}' does not exist")]
     CratePathDoesntExist(PathBuf),
     #[error(
-        "Without feature `rustc_codegen_spirv`, you need to set the path of the dylib using `rustc_codegen_spirv_location(...)`"
+        "Without feature `rustc_codegen_spirv`, you need to set the path of the dylib with `rustc_codegen_spirv_location`"
     )]
     MissingRustcCodegenSpirvDylib,
     #[error("`rustc_codegen_spirv_location` path '{0}' is not a file")]
     RustcCodegenSpirvDylibDoesNotExist(PathBuf),
+    #[error(
+        "Without feature `include_target_specs`, instead of setting a `target`, \
+        you need to set the path of the target spec file of your particular target with `path_to_target_spec`"
+    )]
+    MissingTargetSpec,
     #[error("build failed")]
     BuildFailed,
     #[error("multi-module build cannot be used with print_metadata = MetadataPrintout::Full")]
@@ -352,13 +358,13 @@ impl Default for ShaderCrateFeatures {
     }
 }
 
-#[non_exhaustive]
 #[derive(Clone, Debug, serde::Deserialize, serde::Serialize)]
 #[cfg_attr(feature = "clap", derive(clap::Parser))]
 pub struct SpirvBuilder {
     #[cfg_attr(feature = "clap", clap(skip))]
     pub path_to_crate: Option<PathBuf>,
-    /// Whether to print build.rs cargo metadata (e.g. cargo:rustc-env=var=val). Defaults to [`MetadataPrintout::Full`].
+    /// Whether to print build.rs cargo metadata (e.g. cargo:rustc-env=var=val). Defaults to [`MetadataPrintout::None`].
+    /// Within build scripts, set it to [`MetadataPrintout::DependencyOnly`] or [`MetadataPrintout::Full`] to ensure the build script is rerun on code changes.
     #[cfg_attr(feature = "clap", clap(skip))]
     pub print_metadata: MetadataPrintout,
     /// Build in release. Defaults to true.
@@ -975,13 +981,18 @@ fn invoke_rustc(builder: &SpirvBuilder) -> Result<PathBuf, SpirvBuilderError> {
     // target_spec jsons, some later version requires them, some earlier
     // version fails with them (notably our 0.9.0 release)
     if toolchain_rustc_version >= Version::new(1, 76, 0) {
-        cargo
-            .arg("--target")
-            .arg(builder.path_to_target_spec.clone().unwrap_or_else(|| {
-                PathBuf::from(env!("CARGO_MANIFEST_DIR"))
-                    .join("target-specs")
-                    .join(format!("{}.json", target))
-            }));
+        let path_opt = builder.path_to_target_spec.clone();
+        let path;
+        #[cfg(feature = "include_target_specs")]
+        {
+            path = path_opt
+                .unwrap_or_else(|| PathBuf::from(format!("{TARGET_SPEC_DIR_PATH}/{target}.json")));
+        }
+        #[cfg(not(feature = "include_target_specs"))]
+        {
+            path = path_opt.ok_or(SpirvBuilderError::MissingTargetSpec)?;
+        }
+        cargo.arg("--target").arg(path);
     } else {
         cargo.arg("--target").arg(target);
     }

docs/src/writing-shader-crates.md

@@ -120,7 +120,7 @@ how to build SPIR-V. Here are a few things we need to mention there.
 
 - Path to a spec of a target you're compiling for (see [platform support](./platform-support.md)).
   These specs reside in a directory inside the `spirv-builder` crate and an example relative path
-  could look like `../rust-gpu/crates/spirv-builder/target-specs/spirv-unknown-spv1.3.json`.
+  could look like `../rust-gpu/crates/rustc_codegen_spirv-types/target-specs/spirv-unknown-spv1.3.json`.
 - Absolute path to the `rustc_codegen_spirv` dynamic library that we built above.
 - Some additional options.
 

tests/Cargo.toml

@@ -15,6 +15,7 @@ use-compiled-tools = ["rustc_codegen_spirv/use-compiled-tools"]
 
 [dependencies]
 compiletest = { version = "0.11.2", package = "compiletest_rs" }
-rustc_codegen_spirv.workspace = true
+rustc_codegen_spirv = { workspace = true }
+rustc_codegen_spirv_target_specs = { workspace = true, features = ["dir_path"] }
 clap = { version = "4", features = ["derive"] }
 itertools = "0.10.5"

tests/src/main.rs

@@ -1,5 +1,6 @@
 use clap::Parser;
 use itertools::Itertools as _;
+use rustc_codegen_spirv_target_specs::TARGET_SPEC_DIR_PATH;
 use std::{
     env, io,
     path::{Path, PathBuf},
@@ -30,10 +31,7 @@ impl Opt {
 const SPIRV_TARGET_PREFIX: &str = "spirv-unknown-";
 
 fn target_spec_json(target: &str) -> String {
-    format!(
-        "{}/../crates/spirv-builder/target-specs/{target}.json",
-        env!("CARGO_MANIFEST_DIR")
-    )
+    format!("{TARGET_SPEC_DIR_PATH}/{target}.json")
 }
 
 #[derive(Copy, Clone)]