[lld] r347620 - [Common] Threads: use function_ref instead of std::function

[Fangrui Song via llvm-commits]

Author: maskray
Date: Mon Nov 26 16:26:50 2018
New Revision: 347620

URL: http://llvm.org/viewvc/llvm-project?rev=347620&view=rev
Log:
[Common] Threads: use function_ref instead of std::function

The benefits are:

a) Performance (very minor): it removes a heap allocation of the std::function constructor (template<class F> function(F f))
b) Clarity: it suggests that the callable's lifetime should end after the callee returns. Such callback is widely used in llvm. lld also uses it a lot.

Reviewers: ruiu, rnk, pcc

Reviewed By: ruiu

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54813

Modified:
    lld/trunk/include/lld/Common/Threads.h

Modified: lld/trunk/include/lld/Common/Threads.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/include/lld/Common/Threads.h?rev=347620&r1=347619&r2=347620&view=diff
==============================================================================
--- lld/trunk/include/lld/Common/Threads.h (original)
+++ lld/trunk/include/lld/Common/Threads.h Mon Nov 26 16:26:50 2018
@@ -74,7 +74,7 @@ template <typename R, class FuncTy> void
 }
 
 inline void parallelForEachN(size_t Begin, size_t End,
-                             std::function<void(size_t)> Fn) {
+                             llvm::function_ref<void(size_t)> Fn) {
   if (ThreadsEnabled)
     for_each_n(llvm::parallel::par, Begin, End, Fn);
   else