Add test for #80981, print cranelift version

[osa1]

• Regression test added for Fix -Cpasses=list and llvm version print with -vV #80981
• -vV now prints cranelift version when cranelift backend is used

[rust-highfive]

r? @Mark-Simulacrum

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[osa1]

@bjorn3 this will fail when cranelift backend is used, right? Is cranelift version or anything like that printed in -vV when cranelift is used as the backend?

[bjorn3]

Can you add a test for -Cpasses=list too?

@bjorn3 this will fail when cranelift backend is used, right?

Indeed

Is cranelift version or anything like that printed in -vV when cranelift is used as the backend?

Nope, nothing is printed. There is a cfg!(feature = "llvm") for the print_version call as llvm is hard coded. Maybe get_builtin_codegen_backend could use the default codegen backend when "" is passed? I can then implement print_version in cg_clif.

[osa1]

@bjorn3 how about this

diff --git a/compiler/rustc_driver/Cargo.toml b/compiler/rustc_driver/Cargo.toml
index b88b556d143..26f657d4c1a 100644
--- a/compiler/rustc_driver/Cargo.toml
+++ b/compiler/rustc_driver/Cargo.toml
@@ -40,4 +40,5 @@ winapi = { version = "0.3", features = ["consoleapi", "debugapi", "processenv"]
 
 [features]
 llvm = ['rustc_interface/llvm']
+cranelift = ['rustc_interface/cranelift']
 max_level_info = ['tracing/max_level_info']
diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index f8ceb94916e..988dcb23ac5 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -800,6 +800,8 @@ fn unw(x: Option<&str>) -> &str {
         println!("release: {}", unw(util::release_str()));
         if cfg!(feature = "llvm") {
             get_builtin_codegen_backend("llvm")().print_version();
+        } else if cfg!(feature = "cranelift") {
+            get_builtin_codegen_backend("cranelift")().print_version();
         }
     }
 }
@@ -1089,6 +1091,8 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
     if cg_flags.iter().any(|x| *x == "passes=list") {
         if cfg!(feature = "llvm") {
             get_builtin_codegen_backend("llvm")().print_passes();
+        } else if cfg!(feature = "cranelift") {
+            get_builtin_codegen_backend("cranelift")().print_passes();
         }
         return None;
     }
diff --git a/compiler/rustc_interface/Cargo.toml b/compiler/rustc_interface/Cargo.toml
index 2481a27dee7..c9f254104e1 100644
--- a/compiler/rustc_interface/Cargo.toml
+++ b/compiler/rustc_interface/Cargo.toml
@@ -29,6 +29,7 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_codegen_ssa = { path = "../rustc_codegen_ssa" }
 rustc_symbol_mangling = { path = "../rustc_symbol_mangling" }
 rustc_codegen_llvm = { path = "../rustc_codegen_llvm", optional = true }
+rustc_codegen_cranelift = { path = "../rustc_codegen_cranelift", optional = true }
 rustc_hir = { path = "../rustc_hir" }
 rustc_metadata = { path = "../rustc_metadata" }
 rustc_mir = { path = "../rustc_mir" }
@@ -52,3 +53,4 @@ rustc_target = { path = "../rustc_target" }
 
 [features]
 llvm = ['rustc_codegen_llvm']
+cranelift = ['rustc_codegen_cranelift']
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index f34990a1a10..a22ec92ed5b 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -370,6 +370,8 @@ pub fn get_builtin_codegen_backend(backend_name: &str) -> fn() -> Box<dyn Codege
     match backend_name {
         #[cfg(feature = "llvm")]
         "llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
+        #[cfg(feature = "cranelift")]
+        "cranelift" => rustc_codegen_cranelift::CraneliftCodegenBackend::new,
         _ => get_codegen_sysroot(backend_name),
     }
 }

We can then implement print_version and print_passes for the cranelift backend.

[bjorn3]

rustc_codegen_cranelift can't be a dependency of rustc_interface as rustc_codegen_cranelift depends on rustc_interface through rustc_driver. rustc_codegen_cranelift is dynamically loaded at runtime. For this reason the compiler/rustc_interface/src/util.rs change is also not necessary as get_codegen_sysroot can already load rustc_codegen_cranelift.

[osa1]

OK, thanks. I think that's fine. I'll push rest of the changes to this branch, with print_version and print_passes for the cranelift backend.

I don't know what to print in those methods though. Any ideas?

[bjorn3]

print_passes can be left unimplemented for cg_clif. For print_version I think I will implement it myself.

[osa1]

For print_version I think I will implement it myself.

OK. Please ping me when you do it so I can finish this PR.

[osa1]

@bjorn3 Hm, can I not just use https://docs.rs/cranelift/0.69.0/cranelift/constant.VERSION.html ?

[bjorn3]

@bjorn3 Hm, can I not just use https://docs.rs/cranelift/0.69.0/cranelift/constant.VERSION.html ?

Yeah, I guess so.

[Dylan-DPC-zz]

@osa1 any updates on this?

[osa1]

@Dylan-DPC thanks for the ping, I updated the PR now.

@bors -S-waiting-on-author +S-waiting-on-review

[osa1]

@rustbot label: +S-waiting-on-review -S-waiting-on-author

[Mark-Simulacrum]

The PR description suggests this will print the cranelift version, but the version code still seems to contain the LLVM feature guard, which seems surprising. Does this work with cranelift? What am I missing?

[osa1]

Sigh.. You're right that the cranelift version is never shown. I don't know how to make it work, without refactoring how cranelift backend is loaded/linked significantly. Let me explain my motivation for this PR and maybe someone can help.

First, I don't care about cranelift version. The reason why I added this is I think there is no way to run a test only when LLVM backend is enabled. So the new test that makes sure -vV shows the LLVM version may be broken in some configurations. I don't know if this is a real problem or not, perhaps it's fine to assume LLVM always. Can anyone comment on this?

Now, the reason why I want -vV to show LLVM version always (and catch any breaking patches before landing) is because I'm using nightly rustc to build Wasm libraries which I link with other Wasm code generated by a different toolchain, using LLVM's wasm-ld. Because Wasm doesn't have a stable ABI I need to make sure the rustc's LLVM, Wasm I generate with custom toolchain, and wasm-ld are all compatible. For this I need to compare versions of rustc's LLVM with wasm-ld (and then manually make sure my toolchain generates compatible Wasm). So I need -vV to work always (in nightly) and as reported in #77975 (comment) it got broken in the past. This PR is to make sure it won't get broken in the future.

---

If it's fine to assume LLVM always, I'll update the test to just check LLVM version (not cranelift version) and revert print_version change in cranelift backend.