Auto merge of #52266 - michaelwoerister:incr-thinlto-preliminaries, r=alexcrichton

Preliminary work for incremental ThinLTO.

Since implementing incremental ThinLTO is a bit more involved than I initially thought, I'm splitting out some of the things that already work. This PR (1) adds a way accessing some ThinLTO information in `rustc` and (2) does some cleanup around CGU/object file naming (which makes things quite a bit nicer).

This is probably best reviewed one commit at a time.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/librustc_llvm/ffi.rs b/src/librustc_llvm/ffi.rs
index 0497de940ca..551f1cda6f0 100644
--- a/src/librustc_llvm/ffi.rs
+++ b/src/librustc_llvm/ffi.rs
@@ -350,6 +350,10 @@ pub enum ThinLTOData {}
 /// LLVMRustThinLTOBuffer
 pub enum ThinLTOBuffer {}
 
+// LLVMRustModuleNameCallback
+pub type ThinLTOModuleNameCallback =
+    unsafe extern "C" fn(*mut c_void, *const c_char, *const c_char);
+
 /// LLVMRustThinLTOModule
 #[repr(C)]
 pub struct ThinLTOModule {
@@ -1778,6 +1782,11 @@ extern "C" {
         Data: *const ThinLTOData,
         Module: ModuleRef,
     ) -> bool;
+    pub fn LLVMRustGetThinLTOModuleImports(
+        Data: *const ThinLTOData,
+        ModuleNameCallback: ThinLTOModuleNameCallback,
+        CallbackPayload: *mut c_void,
+    );
     pub fn LLVMRustFreeThinLTOData(Data: *mut ThinLTOData);
     pub fn LLVMRustParseBitcodeForThinLTO(
         Context: ContextRef,