Auto merge of #90617 - tmiasko:time-trace-threads, r=wesleywiser

Initialize LLVM time trace profiler on each code generation thread

In https://reviews.llvm.org/D71059 LLVM 11, the time trace profiler was
extended to support multiple threads.

`timeTraceProfilerInitialize` creates a thread local profiler instance.
When a thread finishes `timeTraceProfilerFinishThread` moves a thread
local instance into a global collection of instances. Finally when all
codegen work is complete `timeTraceProfilerWrite` writes data from the
current thread local instance and the instances in global collection
of instances.

Previously, the profiler was intialized on a single thread only. Since
this thread performs no code generation on its own, the resulting
profile was empty.

Update LLVM codegen to initialize & finish time trace profiler on each
code generation thread.

cc `@tmandry`
r? `@wesleywiser`

1 files changed, 2 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 21d2388fc30..749eec459ac 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1737,6 +1737,8 @@ extern "C" {
 
     pub fn LLVMTimeTraceProfilerInitialize();
 
+    pub fn LLVMTimeTraceProfilerFinishThread();
+
     pub fn LLVMTimeTraceProfilerFinish(FileName: *const c_char);
 
     pub fn LLVMAddAnalysisPasses(T: &'a TargetMachine, PM: &PassManager<'a>);