Rollup merge of #131037 - madsmtm:move-llvm-target-versioning, r=petrochenkov

Move versioned Apple LLVM targets from `rustc_target` to `rustc_codegen_ssa`

Fully specified LLVM targets contain the OS version on macOS/iOS/tvOS/watchOS/visionOS, and this version depends on the deployment target environment variables like `MACOSX_DEPLOYMENT_TARGET`, `IPHONEOS_DEPLOYMENT_TARGET` etc.

We would like to move this to later in the compilation pipeline, both because it feels impure to access environment variables when fetching target information, but mostly because we need access to more information from rust-lang/rust#130883 to do rust-lang/rust#118204. See also rust-lang/rust#129342 (comment) for some discussion.

The first and second commit does the actual refactor, it should be a non-functional change, the third commit adds diagnostics for invalid deployment targets, which are now possible to do because we have access to the session.

Tested with the same commands as in rust-lang/rust#130435.

r? ``````@petrochenkov``````

Author: matthiaskrgr

src/lib.rs

@@ -40,6 +40,7 @@ use std::sync::Arc;
 use cranelift_codegen::isa::TargetIsa;
 use cranelift_codegen::settings::{self, Configurable};
 use rustc_codegen_ssa::CodegenResults;
+use rustc_codegen_ssa::back::versioned_llvm_target;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_errors::ErrorGuaranteed;
@@ -260,7 +261,9 @@ impl CodegenBackend for CraneliftCodegenBackend {
 }
 
 fn target_triple(sess: &Session) -> target_lexicon::Triple {
-    match sess.target.llvm_target.parse() {
+    // FIXME(madsmtm): Use `sess.target.llvm_target` once target-lexicon supports unversioned macOS.
+    // See <https://github.com/bytecodealliance/target-lexicon/pull/113>
+    match versioned_llvm_target(sess).parse() {
         Ok(triple) => triple,
         Err(err) => sess.dcx().fatal(format!("target not recognized: {}", err)),
     }