refactor: Remove LLVMRustInsertPrivateGlobal

Since it can easily be implemented using the existing LLVM C API in
terms of `LLVMAddGlobal` and `LLVMSetLinkage`.

Author: AMS21

compiler/rustc_codegen_llvm/src/declare.rs

@@ -24,6 +24,7 @@ use tracing::debug;
 
 use crate::abi::FnAbiLlvmExt;
 use crate::attributes;
+use crate::builder::UNNAMED;
 use crate::common::AsCCharPtr;
 use crate::context::{CodegenCx, GenericCx, SCx, SimpleCx};
 use crate::llvm::AttributePlace::Function;
@@ -234,7 +235,9 @@ impl<'ll, CX: Borrow<SCx<'ll>>> GenericCx<'ll, CX> {
     ///
     /// Use this function when you intend to define a global without a name.
     pub(crate) fn define_private_global(&self, ty: &'ll Type) -> &'ll Value {
-        unsafe { llvm::LLVMRustInsertPrivateGlobal(self.llmod(), ty) }
+        let global = unsafe { llvm::LLVMAddGlobal(self.llmod(), ty, UNNAMED) };
+        unsafe { llvm::LLVMSetLinkage(global, llvm::Linkage::PrivateLinkage) };
+        global
     }
 
     /// Gets declared value by name.

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1954,7 +1954,6 @@ unsafe extern "C" {
         NameLen: size_t,
         T: &'a Type,
     ) -> &'a Value;
-    pub(crate) fn LLVMRustInsertPrivateGlobal<'a>(M: &'a Module, T: &'a Type) -> &'a Value;
     pub(crate) fn LLVMRustGetNamedValue(
         M: &Module,
         Name: *const c_char,

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -228,12 +228,6 @@ extern "C" LLVMValueRef LLVMRustGetOrInsertGlobal(LLVMModuleRef M,
   return wrap(GV);
 }
 
-extern "C" LLVMValueRef LLVMRustInsertPrivateGlobal(LLVMModuleRef M,
-                                                    LLVMTypeRef Ty) {
-  return wrap(new GlobalVariable(*unwrap(M), unwrap(Ty), false,
-                                 GlobalValue::PrivateLinkage, nullptr));
-}
-
 // Must match the layout of `rustc_codegen_llvm::llvm::ffi::AttributeKind`.
 enum class LLVMRustAttributeKind {
   AlwaysInline = 0,