diff --git a/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs b/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs
index e2fa5e488ed..45de284d22a 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/diagnostic.rs
@@ -20,19 +20,6 @@ pub enum OptimizationDiagnosticKind {
     OptimizationRemarkOther,
 }
 
-impl OptimizationDiagnosticKind {
-    pub fn describe(self) -> &'static str {
-        match self {
-            OptimizationRemark | OptimizationRemarkOther => "remark",
-            OptimizationMissed => "missed",
-            OptimizationAnalysis => "analysis",
-            OptimizationAnalysisFPCommute => "floating-point",
-            OptimizationAnalysisAliasing => "aliasing",
-            OptimizationFailure => "failure",
-        }
-    }
-}
-
 pub struct OptimizationDiagnostic<'ll> {
     pub kind: OptimizationDiagnosticKind,
     pub pass_name: String,
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index b89408ab75a..9ee6d39fdc9 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -572,16 +572,6 @@ pub enum ArchiveKind {
     K_COFF,
 }
 
-/// LLVMRustPassKind
-#[derive(Copy, Clone, PartialEq, Debug)]
-#[repr(C)]
-#[allow(dead_code)] // Variants constructed by C++.
-pub enum PassKind {
-    Other,
-    Function,
-    Module,
-}
-
 // LLVMRustThinLTOData
 extern "C" {
     pub type ThinLTOData;
@@ -592,10 +582,6 @@ extern "C" {
     pub type ThinLTOBuffer;
 }
 
-// LLVMRustModuleNameCallback
-pub type ThinLTOModuleNameCallback =
-    unsafe extern "C" fn(*mut c_void, *const c_char, *const c_char);
-
 /// LLVMRustThinLTOModule
 #[repr(C)]
 pub struct ThinLTOModule {
@@ -661,9 +647,6 @@ extern "C" {
 }
 #[repr(C)]
 pub struct Builder<'a>(InvariantOpaque<'a>);
-extern "C" {
-    pub type MemoryBuffer;
-}
 #[repr(C)]
 pub struct PassManager<'a>(InvariantOpaque<'a>);
 extern "C" {
@@ -1032,7 +1015,6 @@ extern "C" {
     pub fn LLVMSetDataLayout(M: &Module, Triple: *const c_char);
 
     /// See Module::setModuleInlineAsm.
-    pub fn LLVMSetModuleInlineAsm2(M: &Module, Asm: *const c_char, AsmLen: size_t);
     pub fn LLVMRustAppendModuleInlineAsm(M: &Module, Asm: *const c_char, AsmLen: size_t);
 
     /// See llvm::LLVMTypeKind::getTypeID.
@@ -1186,7 +1168,6 @@ extern "C" {
     pub fn LLVMGetInitializer(GlobalVar: &Value) -> Option<&Value>;
     pub fn LLVMSetInitializer<'a>(GlobalVar: &'a Value, ConstantVal: &'a Value);
     pub fn LLVMIsThreadLocal(GlobalVar: &Value) -> Bool;
-    pub fn LLVMSetThreadLocal(GlobalVar: &Value, IsThreadLocal: Bool);
     pub fn LLVMSetThreadLocalMode(GlobalVar: &Value, Mode: ThreadLocalMode);
     pub fn LLVMIsGlobalConstant(GlobalVar: &Value) -> Bool;
     pub fn LLVMSetGlobalConstant(GlobalVar: &Value, IsConstant: Bool);
@@ -2267,7 +2248,6 @@ extern "C" {
 
     pub fn LLVMIsAConstantInt(value_ref: &Value) -> Option<&ConstantInt>;
 
-    pub fn LLVMRustPassKind(Pass: &Pass) -> PassKind;
     pub fn LLVMRustFindAndCreatePass(Pass: *const c_char) -> Option<&'static mut Pass>;
     pub fn LLVMRustCreateAddressSanitizerFunctionPass(Recover: bool) -> &'static mut Pass;
     pub fn LLVMRustCreateModuleAddressSanitizerPass(Recover: bool) -> &'static mut Pass;
@@ -2384,7 +2364,6 @@ extern "C" {
     ) -> LLVMRustResult;
     pub fn LLVMRustSetLLVMOptions(Argc: c_int, Argv: *const *const c_char);
     pub fn LLVMRustPrintPasses();
-    pub fn LLVMRustGetInstructionCount(M: &Module) -> u32;
     pub fn LLVMRustSetNormalizedTarget(M: &Module, triple: *const c_char);
     pub fn LLVMRustAddAlwaysInlinePass(P: &PassManagerBuilder, AddLifetimes: bool);
     pub fn LLVMRustRunRestrictionPass(M: &Module, syms: *const *const c_char, len: size_t);
@@ -2482,7 +2461,6 @@ extern "C" {
     pub fn LLVMRustPositionBuilderAtStart<'a>(B: &Builder<'a>, BB: &'a BasicBlock);
 
     pub fn LLVMRustSetComdat<'a>(M: &'a Module, V: &'a Value, Name: *const c_char, NameLen: size_t);
-    pub fn LLVMRustUnsetComdat(V: &Value);
     pub fn LLVMRustSetModulePICLevel(M: &Module);
     pub fn LLVMRustSetModulePIELevel(M: &Module);
     pub fn LLVMRustSetModuleCodeModel(M: &Module, Model: CodeModel);
@@ -2514,11 +2492,6 @@ extern "C" {
         Module: &Module,
         Target: &TargetMachine,
     ) -> bool;
-    pub fn LLVMRustGetThinLTOModuleImports(
-        Data: *const ThinLTOData,
-        ModuleNameCallback: ThinLTOModuleNameCallback,
-        CallbackPayload: *mut c_void,
-    );
     pub fn LLVMRustFreeThinLTOData(Data: &'static mut ThinLTOData);
     pub fn LLVMRustParseBitcodeForLTO(
         Context: &Context,
diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
index 8e5e1a8b2a3..6602a4ab863 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
@@ -166,12 +166,6 @@ pub fn SetUniqueComdat(llmod: &Module, val: &Value) {
     }
 }
 
-pub fn UnsetComdat(val: &Value) {
-    unsafe {
-        LLVMRustUnsetComdat(val);
-    }
-}
-
 pub fn SetUnnamedAddress(global: &Value, unnamed: UnnamedAddr) {
     unsafe {
         LLVMSetUnnamedAddress(global, unnamed);
diff --git a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
index e0f10f77e89..0a6bd49992d 100644
--- a/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp
@@ -90,23 +90,6 @@ extern "C" void LLVMTimeTraceProfilerFinish(const char* FileName) {
   timeTraceProfilerCleanup();
 }
 
-enum class LLVMRustPassKind {
-  Other,
-  Function,
-  Module,
-};
-
-static LLVMRustPassKind toRust(PassKind Kind) {
-  switch (Kind) {
-  case PT_Function:
-    return LLVMRustPassKind::Function;
-  case PT_Module:
-    return LLVMRustPassKind::Module;
-  default:
-    return LLVMRustPassKind::Other;
-  }
-}
-
 extern "C" LLVMPassRef LLVMRustFindAndCreatePass(const char *PassName) {
 #if LLVM_VERSION_LT(15, 0)
   StringRef SR(PassName);
@@ -172,12 +155,6 @@ extern "C" LLVMPassRef LLVMRustCreateHWAddressSanitizerPass(bool Recover) {
 #endif
 }
 
-extern "C" LLVMRustPassKind LLVMRustPassKind(LLVMPassRef RustPass) {
-  assert(RustPass);
-  Pass *Pass = unwrap(RustPass);
-  return toRust(Pass->getPassKind());
-}
-
 extern "C" void LLVMRustAddPass(LLVMPassManagerRef PMR, LLVMPassRef RustPass) {
 #if LLVM_VERSION_LT(15, 0)
   assert(RustPass);
@@ -1604,28 +1581,6 @@ LLVMRustPrepareThinLTOImport(const LLVMRustThinLTOData *Data, LLVMModuleRef M,
   return true;
 }
 
-extern "C" typedef void (*LLVMRustModuleNameCallback)(void*, // payload
-                                                      const char*, // importing module name
-                                                      const char*); // imported module name
-
-// Calls `module_name_callback` for each module import done by ThinLTO.
-// The callback is provided with regular null-terminated C strings.
-extern "C" void
-LLVMRustGetThinLTOModules(const LLVMRustThinLTOData *data,
-                                LLVMRustModuleNameCallback module_name_callback,
-                                void* callback_payload) {
-  for (const auto& importing_module : data->ImportLists) {
-    const std::string importing_module_id = importing_module.getKey().str();
-    const auto& imports = importing_module.getValue();
-    for (const auto& imported_module : imports) {
-      const std::string imported_module_id = imported_module.getKey().str();
-      module_name_callback(callback_payload,
-                           importing_module_id.c_str(),
-                           imported_module_id.c_str());
-    }
-  }
-}
-
 // This struct and various functions are sort of a hack right now, but the
 // problem is that we've got in-memory LLVM modules after we generate and
 // optimize all codegen-units for one compilation in rustc. To be compatible
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index fffc2dd2b84..ef1a65488e2 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -88,10 +88,6 @@ extern "C" char *LLVMRustGetLastError(void) {
   return Ret;
 }
 
-extern "C" unsigned int LLVMRustGetInstructionCount(LLVMModuleRef M) {
-  return unwrap(M)->getInstructionCount();
-}
-
 extern "C" void LLVMRustSetLastError(const char *Err) {
   free((void *)LastError);
   LastError = strdup(Err);
@@ -1529,11 +1525,6 @@ extern "C" void LLVMRustSetComdat(LLVMModuleRef M, LLVMValueRef V,
   }
 }
 
-extern "C" void LLVMRustUnsetComdat(LLVMValueRef V) {
-  GlobalObject *GV = unwrap<GlobalObject>(V);
-  GV->setComdat(nullptr);
-}
-
 enum class LLVMRustLinkage {
   ExternalLinkage = 0,
   AvailableExternallyLinkage = 1,