[PATCH] D13107: Support for function summary index bitcode sections and files

[Eric Christopher via llvm-commits]

echristo added a subscriber: echristo.
echristo added a comment.

Hi Teresa,

A couple of inline comments, I'll have more, but I just thought I'd send a couple out.

One general comment:

How expensive is the index (size and time to compute)? Is it worth always including in the module?

Thanks!

-eric


================
Comment at: llvm/trunk/include/llvm/IR/FunctionInfo.h:57
@@ +56,3 @@
+  /// Number of instructions (ignoring debug instructions, e.g.) computed
+  /// during the initial compile step when the function index is first built.
+  unsigned InstCount;
----------------
Comment nit: "during the initial compile step" seems weird and not wholly accurate.

Relatedly: would a transform be expected to keep it up to date? Is it recomputed on every write? (Seems reasonable, but costly).

================
Comment at: llvm/trunk/include/llvm/IR/FunctionInfo.h:61-62
@@ +60,4 @@
+ public:
+  /// Construct a summary object from summary data expected for all
+  /// summary records.
+  FunctionSummary(unsigned NumInsts) : InstCount(NumInsts) {}
----------------
This comment seems a bit confusing. Could you elaborate more?


Repository:
  rL LLVM

http://reviews.llvm.org/D13107