[lld] r270348 - Store section contents to SectionPiece. NFC.

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Sat May 21 20:15:32 2016
New Revision: 270348

URL: http://llvm.org/viewvc/llvm-project?rev=270348&view=rev
Log:
Store section contents to SectionPiece. NFC.

So that we don't need to cut a slice when we use a SectionPiece.

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

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=270348&r1=270347&r2=270348&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Sat May 21 20:15:32 2016
@@ -422,8 +422,9 @@ typename ELFT::uint EHInputSection<ELFT>
   return Piece->OutputOff + Addend;
 }
 
-static size_t findNull(StringRef S, size_t EntSize) {
+static size_t findNull(ArrayRef<uint8_t> A, size_t EntSize) {
   // Optimize the common case.
+  StringRef S((const char *)A.data(), A.size());
   if (EntSize == 1)
     return S.find(0);
 
@@ -440,8 +441,7 @@ MergeInputSection<ELFT>::MergeInputSecti
                                            const Elf_Shdr *Header)
     : SplitInputSection<ELFT>(F, Header, InputSectionBase<ELFT>::Merge) {
   uintX_t EntSize = Header->sh_entsize;
-  ArrayRef<uint8_t> D = this->getSectionData();
-  StringRef Data((const char *)D.data(), D.size());
+  ArrayRef<uint8_t> Data = this->getSectionData();
 
   if (Header->sh_flags & SHF_STRINGS) {
     uintX_t Offset = 0;
@@ -450,8 +450,8 @@ MergeInputSection<ELFT>::MergeInputSecti
       if (End == StringRef::npos)
         fatal("string is not null terminated");
       uintX_t Size = End + EntSize;
-      this->Pieces.emplace_back(Offset, Size);
-      Data = Data.substr(Size);
+      this->Pieces.emplace_back(Offset, Data.slice(0, Size));
+      Data = Data.slice(Size);
       Offset += Size;
     }
     return;
@@ -461,7 +461,7 @@ MergeInputSection<ELFT>::MergeInputSecti
   size_t Size = Data.size();
   assert((Size % EntSize) == 0);
   for (unsigned I = 0, N = Size; I != N; I += EntSize)
-    this->Pieces.emplace_back(I, EntSize);
+    this->Pieces.emplace_back(I, Data.slice(I, EntSize));
 }
 
 template <class ELFT>
@@ -498,7 +498,7 @@ typename ELFT::uint MergeInputSection<EL
   // Map the base to the offset in the output section and cache it.
   ArrayRef<uint8_t> D = this->getSectionData();
   StringRef Data((const char *)D.data(), D.size());
-  StringRef Entry = Data.substr(Piece.InputOff, Piece.Size);
+  StringRef Entry = Data.substr(Piece.InputOff, Piece.size());
   auto *MOS = static_cast<MergeOutputSection<ELFT> *>(this->OutSec);
   Piece.OutputOff = MOS->getOffset(Entry);
   return Piece.OutputOff + Addend;

Modified: lld/trunk/ELF/InputSection.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.h?rev=270348&r1=270347&r2=270348&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.h (original)
+++ lld/trunk/ELF/InputSection.h Sat May 21 20:15:32 2016
@@ -132,11 +132,13 @@ template <class ELFT> InputSectionBase<E
 
 // SectionPiece represents a piece of splittable section contents.
 struct SectionPiece {
-  SectionPiece(size_t Off, size_t Size)
-      : InputOff(Off), Size(Size), Live(!Config->GcSections) {}
+  SectionPiece(size_t Off, ArrayRef<uint8_t> Data)
+      : InputOff(Off), Data(Data), Live(!Config->GcSections) {}
+  size_t size() const { return Data.size(); }
+
   size_t InputOff;
-  size_t Size;
   size_t OutputOff = -1;
+  ArrayRef<uint8_t> Data; // slice of the input section
   bool Live;
 };
 
@@ -156,6 +158,7 @@ public:
   // rather than a single large blob of data.
   std::vector<SectionPiece> Pieces;
 
+  // Returns the SectionPiece at a given input section offset.
   SectionPiece *getSectionPiece(uintX_t Offset);
 };
 

Modified: lld/trunk/ELF/OutputSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=270348&r1=270347&r2=270348&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.cpp (original)
+++ lld/trunk/ELF/OutputSections.cpp Sat May 21 20:15:32 2016
@@ -977,9 +977,7 @@ EHRegion<ELFT>::EHRegion(EHInputSection<
     : Sec(Sec), Index(Index) {}
 
 template <class ELFT> ArrayRef<uint8_t> EHRegion<ELFT>::data() const {
-  ArrayRef<uint8_t> SecData = Sec->getSectionData();
-  SectionPiece &Piece = Sec->Pieces[Index];
-  return SecData.slice(Piece.InputOff, Piece.Size);
+  return Sec->Pieces[Index].Data;
 }
 
 template <class ELFT>
@@ -1147,7 +1145,7 @@ void EHOutputSection<ELFT>::addSectionAu
     StringRef Entry((const char *)D.data(), Length);
 
     unsigned Index = Sec->Pieces.size();
-    Sec->Pieces.emplace_back(Offset, Length);
+    Sec->Pieces.emplace_back(Offset, D.slice(0, Length));
 
     uint32_t ID = read32<E>(D.data() + 4);
     if (ID == 0) {
@@ -1271,6 +1269,10 @@ template <class ELFT> void MergeOutputSe
   }
 }
 
+static StringRef toStringRef(ArrayRef<uint8_t> A) {
+  return {(const char *)A.data(), A.size()};
+}
+
 template <class ELFT>
 void MergeOutputSection<ELFT>::addSection(InputSectionBase<ELFT> *C) {
   auto *Sec = cast<MergeInputSection<ELFT>>(C);
@@ -1286,8 +1288,7 @@ void MergeOutputSection<ELFT>::addSectio
     SectionPiece &Piece = Sec->Pieces[I];
     if (!Piece.Live)
       continue;
-    StringRef Entry = Data.substr(Piece.InputOff, Piece.Size);
-    uintX_t OutputOffset = Builder.add(Entry);
+    uintX_t OutputOffset = Builder.add(toStringRef(Piece.Data));
     if (!IsString || !shouldTailMerge())
       Piece.OutputOff = OutputOffset;
   }