Auto merge of #125463 - GuillaumeGomez:rollup-287wx4y, r=GuillaumeGomez

Rollup of 6 pull requests

Successful merges:

 - #125263 (rust-lld: fallback to rustc's sysroot if there's no path to the linker in the target sysroot)
 - #125345 (rustc_codegen_llvm: add support for writing summary bitcode)
 - #125362 (Actually use TAIT instead of emulating it)
 - #125412 (Don't suggest adding the unexpected cfgs to the build-script it-self)
 - #125445 (Migrate `run-make/rustdoc-with-short-out-dir-option` to `rmake.rs`)
 - #125452 (Cleanup check-cfg handling in core and std)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -230,9 +230,12 @@ pub(crate) fn run_thin(
     thin_lto(cgcx, &dcx, modules, upstream_modules, cached_modules, &symbols_below_threshold)
 }
 
-pub(crate) fn prepare_thin(module: ModuleCodegen<ModuleLlvm>) -> (String, ThinBuffer) {
+pub(crate) fn prepare_thin(
+    module: ModuleCodegen<ModuleLlvm>,
+    emit_summary: bool,
+) -> (String, ThinBuffer) {
     let name = module.name;
-    let buffer = ThinBuffer::new(module.module_llvm.llmod(), true);
+    let buffer = ThinBuffer::new(module.module_llvm.llmod(), true, emit_summary);
     (name, buffer)
 }
 
@@ -672,9 +675,9 @@ unsafe impl Send for ThinBuffer {}
 unsafe impl Sync for ThinBuffer {}
 
 impl ThinBuffer {
-    pub fn new(m: &llvm::Module, is_thin: bool) -> ThinBuffer {
+    pub fn new(m: &llvm::Module, is_thin: bool, emit_summary: bool) -> ThinBuffer {
         unsafe {
-            let buffer = llvm::LLVMRustThinLTOBufferCreate(m, is_thin);
+            let buffer = llvm::LLVMRustThinLTOBufferCreate(m, is_thin, emit_summary);
             ThinBuffer(buffer)
         }
     }
@@ -688,6 +691,14 @@ impl ThinBufferMethods for ThinBuffer {
             slice::from_raw_parts(ptr, len)
         }
     }
+
+    fn thin_link_data(&self) -> &[u8] {
+        unsafe {
+            let ptr = llvm::LLVMRustThinLTOBufferThinLinkDataPtr(self.0) as *const _;
+            let len = llvm::LLVMRustThinLTOBufferThinLinkDataLen(self.0);
+            slice::from_raw_parts(ptr, len)
+        }
+    }
 }
 
 impl Drop for ThinBuffer {