Use core via rustc-std-workspace-core in library/panic*

The three panic-related library crates need to have access to `core`,
and `compiler-builtins` needs to be in the crate graph. Rather than
specifying both dependencies, switch these crates to use
`rustc-std-workspace-core` which already does this.

This means there is now a single place that the `compiler-builtins`
dependency needs to get configured, for everything other than `alloc`
and `std`.

Author: tgross35

Cargo.lock

@@ -12,8 +12,7 @@ bench = false
 doc = false
 
 [dependencies]
-core = { path = "../core" }
-compiler_builtins = { path = "../compiler-builtins/compiler-builtins" }
+core = { path = "../rustc-std-workspace-core", package = "rustc-std-workspace-core" }
 
 [target.'cfg(target_os = "android")'.dependencies]
 libc = { version = "0.2", default-features = false }

panic_abort/Cargo.toml

@@ -13,10 +13,9 @@ doc = false
 
 [dependencies]
 alloc = { path = "../alloc" }
-core = { path = "../core" }
-unwind = { path = "../unwind" }
-compiler_builtins = { path = "../compiler-builtins/compiler-builtins" }
 cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
+core = { path = "../rustc-std-workspace-core", package = "rustc-std-workspace-core" }
+unwind = { path = "../unwind" }
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
 libc = { version = "0.2", default-features = false }

panic_unwind/Cargo.toml

@@ -11,6 +11,12 @@ on crates.io will draw a dependency edge to `libcore`, the version defined in
 this repository. That should draw all the dependency edges to ensure Cargo
 builds crates successfully!
 
+`rustc-std-workspace-core` also ensures `compiler-builtins` is in the crate
+graph. This crate is used by other crates in `library/`, other than `std` and
+`alloc`, so the `compiler-builtins` setup only needs to be configured in a
+single place. (Otherwise these crates would just need to depend on `core` and
+`compiler-builtins` separately.)
+
 Note that crates on crates.io need to depend on this crate with the name `core`
 for everything to work correctly. To do that they can use:
 

rustc-std-workspace-core/README.md

@@ -14,9 +14,8 @@ bench = false
 doc = false
 
 [dependencies]
-core = { path = "../core" }
-compiler_builtins = { path = "../compiler-builtins/compiler-builtins" }
 cfg-if = "1.0"
+core = { path = "../rustc-std-workspace-core", package = "rustc-std-workspace-core" }
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
 libc = { version = "0.2.140", features = ['rustc-dep-of-std'], default-features = false }