Rollup merge of #132590 - Zalathar:z-timings-stats, r=jieyouxu

Simplify FFI calls for `-Ztime-llvm-passes` and `-Zprint-codegen-stats`

The existing code for these unstable LLVM-infodump flags was jumping through hoops to pass an allocated C string across the FFI boundary, when it's much simpler to just write to a `&RustString` instead.

1 files changed, 6 insertions, 4 deletions

diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index d99fbfb1632..8508f87c8d3 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1765,11 +1765,13 @@ unsafe extern "C" {
     /// Returns a string describing the last error caused by an LLVMRust* call.
     pub fn LLVMRustGetLastError() -> *const c_char;
 
-    /// Print the pass timings since static dtors aren't picking them up.
-    pub fn LLVMRustPrintPassTimings(size: *const size_t) -> *const c_char;
+    /// Prints the timing information collected by `-Ztime-llvm-passes`.
+    #[expect(improper_ctypes)]
+    pub(crate) fn LLVMRustPrintPassTimings(OutStr: &RustString);
 
-    /// Print the statistics since static dtors aren't picking them up.
-    pub fn LLVMRustPrintStatistics(size: *const size_t) -> *const c_char;
+    /// Prints the statistics collected by `-Zprint-codegen-stats`.
+    #[expect(improper_ctypes)]
+    pub(crate) fn LLVMRustPrintStatistics(OutStr: &RustString);
 
     /// Prepares inline assembly.
     pub fn LLVMRustInlineAsm(