Auto merge of #85700 - Bobo1239:dso_local_ppc64, r=nagisa

Fix static relocation model for PowerPC64

We now also use `should_assume_dso_local()` for declarations and port two
additional cases from clang:
- Exclude PPC64 [1]
- Exclude thread-local variables [2]

[1]: https://github.com/llvm/llvm-project/blob/033138ea452f5f493fb5095e5963419905ad12e1/clang/lib/CodeGen/CodeGenModule.cpp#L1038-L1040
[2]: https://github.com/llvm/llvm-project/blob/033138ea452f5f493fb5095e5963419905ad12e1/clang/lib/CodeGen/CodeGenModule.cpp#L1048-L1050

Tbh I don't know enough about PowerPC(64) to explain why the TOC (table of contents; like the GOT in x86?) is still needed even with the static relocation model. But with these changes [Rust-For-Linux](https://github.com/Rust-for-Linux/linux) runs again on ppc64le. (instead of [getting loaded successfully but crashing](https://github.com/Bobo1239/linux/runs/2646478783?check_suite_focus=true#step:47:358))

r? `@nagisa`

1 files changed, 0 insertions, 24 deletions

diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs
index b296db64ee9..893c909b204 100644
--- a/compiler/rustc_codegen_llvm/src/base.rs
+++ b/compiler/rustc_codegen_llvm/src/base.rs
@@ -218,27 +218,3 @@ pub fn visibility_to_llvm(linkage: Visibility) -> llvm::Visibility {
         Visibility::Protected => llvm::Visibility::Protected,
     }
 }
-
-pub fn linkage_from_llvm(linkage: llvm::Linkage) -> Linkage {
-    match linkage {
-        llvm::Linkage::ExternalLinkage => Linkage::External,
-        llvm::Linkage::AvailableExternallyLinkage => Linkage::AvailableExternally,
-        llvm::Linkage::LinkOnceAnyLinkage => Linkage::LinkOnceAny,
-        llvm::Linkage::LinkOnceODRLinkage => Linkage::LinkOnceODR,
-        llvm::Linkage::WeakAnyLinkage => Linkage::WeakAny,
-        llvm::Linkage::WeakODRLinkage => Linkage::WeakODR,
-        llvm::Linkage::AppendingLinkage => Linkage::Appending,
-        llvm::Linkage::InternalLinkage => Linkage::Internal,
-        llvm::Linkage::PrivateLinkage => Linkage::Private,
-        llvm::Linkage::ExternalWeakLinkage => Linkage::ExternalWeak,
-        llvm::Linkage::CommonLinkage => Linkage::Common,
-    }
-}
-
-pub fn visibility_from_llvm(linkage: llvm::Visibility) -> Visibility {
-    match linkage {
-        llvm::Visibility::Default => Visibility::Default,
-        llvm::Visibility::Hidden => Visibility::Hidden,
-        llvm::Visibility::Protected => Visibility::Protected,
-    }
-}