[lld] r288757 - Inline MergeInputSection::getData().

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Mon Dec  5 20:19:30 2016
New Revision: 288757

URL: http://llvm.org/viewvc/llvm-project?rev=288757&view=rev
Log:
Inline MergeInputSection::getData().

This change seems to make LLD 0.6% faster when linking Clang with
debug info. I don't want us to have lots of local optimizations,
but this function is very hot, and the improvement is small but
not negligible, so I think it's worth doing.

Modified:
    lld/trunk/ELF/InputSection.cpp
    lld/trunk/ELF/InputSection.h

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=288757&r1=288756&r2=288757&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Mon Dec  5 20:19:30 2016
@@ -719,16 +719,6 @@ void MergeInputSection<ELFT>::splitStrin
   }
 }
 
-// Returns I'th piece's data.
-template <class ELFT>
-CachedHashStringRef MergeInputSection<ELFT>::getData(size_t I) const {
-  size_t End =
-      (Pieces.size() - 1 == I) ? this->Data.size() : Pieces[I + 1].InputOff;
-  const SectionPiece &P = Pieces[I];
-  StringRef S = toStringRef(this->Data.slice(P.InputOff, End - P.InputOff));
-  return {S, Hashes[I]};
-}
-
 // Split non-SHF_STRINGS section. Such section is a sequence of
 // fixed size records.
 template <class ELFT>

Modified: lld/trunk/ELF/InputSection.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.h?rev=288757&r1=288756&r2=288757&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.h (original)
+++ lld/trunk/ELF/InputSection.h Mon Dec  5 20:19:30 2016
@@ -194,7 +194,21 @@ public:
   // Splittable sections are handled as a sequence of data
   // rather than a single large blob of data.
   std::vector<SectionPiece> Pieces;
-  llvm::CachedHashStringRef getData(size_t Idx) const;
+
+  // Returns I'th piece's data. This function is very hot when
+  // string merging is enabled, so we want to inline.
+  LLVM_ATTRIBUTE_ALWAYS_INLINE
+  llvm::CachedHashStringRef getData(size_t I) const {
+    size_t Begin = Pieces[I].InputOff;
+    size_t End;
+    if (Pieces.size() - 1 == I)
+      End = this->Data.size();
+    else
+      End = Pieces[I + 1].InputOff;
+
+    StringRef S = {(const char *)(this->Data.data() + Begin), End - Begin};
+    return {S, Hashes[I]};
+  }
 
   // Returns the SectionPiece at a given input section offset.
   SectionPiece *getSectionPiece(uintX_t Offset);