-
Notifications
You must be signed in to change notification settings - Fork 12.9k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
7 changed files
with
189 additions
and
21 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
|
|
@@ -4,4 +4,5 @@ version = "0.0.0" | |
| edition = "2021" | ||
|
|
||
| [dependencies] | ||
| object = "0.34.0" | ||
| wasmparser = "0.118.2" | ||
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,142 @@ | ||
| //! The compiler_builtins library is special. It can call functions in core, but it must not | ||
| //! require linkage against a build of core. If it ever does, building the standard library *may* | ||
| //! result in linker errors, depending on whether the linker in use applies optimizations first or | ||
| //! resolves symbols first. So the portable and safe approach is to forbid such a linkage | ||
| //! requirement entirely. | ||
| //! | ||
| //! In addition, whether compiler_builtins requires linkage against core can depend on optimization | ||
| //! settings. Turning off optimizations and enabling debug assertions tends to produce the most | ||
| //! dependence on core that is possible, so that is the configuration we test here. | ||
| #![deny(warnings)] | ||
|
|
||
| extern crate run_make_support; | ||
|
|
||
| use run_make_support::object; | ||
| use run_make_support::object::read::archive::ArchiveFile; | ||
| use run_make_support::object::read::Object; | ||
| use run_make_support::object::ObjectSection; | ||
| use run_make_support::object::ObjectSymbol; | ||
| use run_make_support::object::RelocationTarget; | ||
| use run_make_support::out_dir; | ||
| use std::collections::HashSet; | ||
|
|
||
| const MANIFEST: &str = r#" | ||
| [package] | ||
| name = "scratch" | ||
| version = "0.1.0" | ||
| edition = "2021" | ||
| [lib] | ||
| path = "lib.rs""#; | ||
|
|
||
| fn main() { | ||
| let target_dir = out_dir().join("target"); | ||
| let target = std::env::var("TARGET").unwrap(); | ||
| if target.starts_with("wasm") || target.starts_with("nvptx") { | ||
| // wasm and nvptx targets don't produce rlib files that object can parse. | ||
| return; | ||
| } | ||
|
|
||
| println!("Testing compiler_builtins for {}", target); | ||
|
|
||
| // Set up the tiniest Cargo project: An empty no_std library. Just enough to run -Zbuild-std. | ||
| let manifest_path = out_dir().join("Cargo.toml"); | ||
| std::fs::write(&manifest_path, MANIFEST.as_bytes()).unwrap(); | ||
| std::fs::write(out_dir().join("lib.rs"), b"#![no_std]").unwrap(); | ||
|
|
||
| let path = std::env::var("PATH").unwrap(); | ||
| let rustc = std::env::var("RUSTC").unwrap(); | ||
| let bootstrap_cargo = std::env::var("BOOTSTRAP_CARGO").unwrap(); | ||
| let status = std::process::Command::new(bootstrap_cargo) | ||
| .args([ | ||
| "build", | ||
| "--manifest-path", | ||
| manifest_path.to_str().unwrap(), | ||
| "-Zbuild-std=core", | ||
| "--target", | ||
| &target, | ||
| ]) | ||
| .env_clear() | ||
| .env("PATH", path) | ||
| .env("RUSTC", rustc) | ||
| .env("RUSTFLAGS", "-Copt-level=0 -Cdebug-assertions=yes") | ||
| .env("CARGO_TARGET_DIR", &target_dir) | ||
| .env("RUSTC_BOOTSTRAP", "1") | ||
| .status() | ||
| .unwrap(); | ||
|
|
||
| assert!(status.success()); | ||
|
|
||
| let rlibs_path = target_dir.join(target).join("debug").join("deps"); | ||
| let compiler_builtins_rlib = std::fs::read_dir(rlibs_path) | ||
| .unwrap() | ||
| .find_map(|e| { | ||
| let path = e.unwrap().path(); | ||
| let file_name = path.file_name().unwrap().to_str().unwrap(); | ||
| if file_name.starts_with("libcompiler_builtins") && file_name.ends_with(".rlib") { | ||
| Some(path) | ||
| } else { | ||
| None | ||
| } | ||
| }) | ||
| .unwrap(); | ||
|
|
||
| // rlib files are archives, where the archive members each a CGU, and we also have one called | ||
| // lib.rmeta which is the encoded metadata. Each of the CGUs is an object file. | ||
| let data = std::fs::read(compiler_builtins_rlib).unwrap(); | ||
|
|
||
| let mut defined_symbols = HashSet::new(); | ||
| let mut undefined_relocations = HashSet::new(); | ||
|
|
||
| let archive = ArchiveFile::parse(&*data).unwrap(); | ||
| for member in archive.members() { | ||
| let member = member.unwrap(); | ||
| if member.name() == b"lib.rmeta" { | ||
| continue; | ||
| } | ||
| let data = member.data(&*data).unwrap(); | ||
| let object = object::File::parse(&*data).unwrap(); | ||
|
|
||
| // Record all defined symbols in this CGU. | ||
| for symbol in object.symbols() { | ||
| if !symbol.is_undefined() { | ||
| let name = symbol.name().unwrap(); | ||
| defined_symbols.insert(name); | ||
| } | ||
| } | ||
|
|
||
| // Find any relocations against undefined symbols. Calls within this CGU are relocations | ||
| // against a defined symbol. | ||
| for (_offset, relocation) in object.sections().flat_map(|section| section.relocations()) { | ||
| let RelocationTarget::Symbol(symbol_index) = relocation.target() else { | ||
| continue; | ||
| }; | ||
| let symbol = object.symbol_by_index(symbol_index).unwrap(); | ||
| if symbol.is_undefined() { | ||
| let name = symbol.name().unwrap(); | ||
| undefined_relocations.insert(name); | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // We can have symbols in the compiler_builtins rlib that are actually from core, if they were | ||
| // monomorphized in the compiler_builtins crate. This is totally fine, because though the call | ||
| // is to a function in core, it's resolved internally. | ||
| // | ||
| // It is normal to have relocations against symbols not defined in the rlib for things like | ||
| // unwinding, or math functions provided the target's platform libraries. Finding these is not | ||
| // a problem, we want to specifically ban relocations against core which are not resolved | ||
| // internally. | ||
| undefined_relocations | ||
| .retain(|symbol| !defined_symbols.contains(symbol) && symbol.contains("core")); | ||
|
|
||
| if !undefined_relocations.is_empty() { | ||
| panic!( | ||
| "compiler_builtins must not link against core, but it does. \n\ | ||
| These symbols may be undefined in a debug build of compiler_builtins:\n\ | ||
| {:?}", | ||
| undefined_relocations | ||
| ); | ||
| } | ||
| } |