[memprof] Use a lambda instead of std::bind (NFC)

[kazutakahirata]

A lambda is a lot shorter than std::bind here.

[llvmbot]

@llvm/pr-subscribers-pgo

Author: Kazu Hirata (kazutakahirata)

Changes

A lambda is a lot shorter than std::bind here.

---

Full diff: https://github.com/llvm/llvm-project/pull/144940.diff

1 Files Affected:

• (modified) llvm/include/llvm/ProfileData/MemProfReader.h (+1-2)

diff --git a/llvm/include/llvm/ProfileData/MemProfReader.h b/llvm/include/llvm/ProfileData/MemProfReader.h
index 4d41d05b1457c..25578ecd06f12 100644
--- a/llvm/include/llvm/ProfileData/MemProfReader.h
+++ b/llvm/include/llvm/ProfileData/MemProfReader.h
@@ -62,8 +62,7 @@ class MemProfReader {
       return make_error<InstrProfError>(instrprof_error::eof);
 
     if (Callback == nullptr)
-      Callback =
-          std::bind(&MemProfReader::idToFrame, this, std::placeholders::_1);
+      Callback = [&](FrameId Id) { return idToFrame(Id); };
 
     CallStackIdConverter<decltype(MemProfData.CallStacks)> CSIdConv(
         MemProfData.CallStacks, Callback);

[snehasish]

lgtm

[firewave]

Using std::mem_fn() would be even shorter.

[kazutakahirata]

Using std::mem_fn() would be even shorter.

Thanks for a comment! IIUC, with std::mem_fn, we would do something like:

Callback = [&](FrameId Id) { return std::mem_fn(&MemProfReader::idToFrame)(this, Id); };

At that point, it's longer than:

Callback = [&](FrameId Id) { return idToFrame(Id); };

I don't think we can "package" this into std::mem_fn.

[firewave]

I thought it is just

Callback = std::mem_fn(&MemProfReader::idToFrame);

But I did not consider that you have to pass the object you are calling on into the call. Sorry for the noise.

[snehasish]

But I did not consider that you have to pass the object you are calling on into the call. Sorry for the noise.

TIL about std::mem_fn from your comment, thanks!