Revert "GC entries of SHF_MERGE sections."

    This reverts commit r267164.

    Revert "Trying to fix the windows build."

    This reverts commit r267168.

Debugging a bootstrap problem.

llvm-svn: 267194

1 files changed, 28 insertions, 16 deletions

diff --git a/lld/ELF/OutputSections.cpp b/lld/ELF/OutputSections.cpp
index efcfcb30b9f..65a59bd025f 100644
--- a/lld/ELF/OutputSections.cpp
+++ b/lld/ELF/OutputSections.cpp
@@ -1132,7 +1132,7 @@ void EHOutputSection<ELFT>::addSectionAux(EHInputSection<ELFT> *S,
     } else {
       if (!HasReloc)
         fatal("FDE doesn't reference another section");
-      InputSectionBase<ELFT> *Target = S->getRelocTarget(*RelI).first;
+      InputSectionBase<ELFT> *Target = S->getRelocTarget(*RelI);
       if (Target && Target->Live) {
         uint32_t CieOffset = Offset + 4 - ID;
         auto I = OffsetToIndex.find(CieOffset);
@@ -1227,6 +1227,19 @@ template <class ELFT> void MergeOutputSection<ELFT>::writeTo(uint8_t *Buf) {
   }
 }
 
+static size_t findNull(StringRef S, size_t EntSize) {
+  // Optimize the common case.
+  if (EntSize == 1)
+    return S.find(0);
+
+  for (unsigned I = 0, N = S.size(); I != N; I += EntSize) {
+    const char *B = S.begin() + I;
+    if (std::all_of(B, B + EntSize, [](char C) { return C == 0; }))
+      return I;
+  }
+  return StringRef::npos;
+}
+
 template <class ELFT>
 void MergeOutputSection<ELFT>::addSection(InputSectionBase<ELFT> *C) {
   auto *S = cast<MergeInputSection<ELFT>>(C);
@@ -1237,32 +1250,31 @@ void MergeOutputSection<ELFT>::addSection(InputSectionBase<ELFT> *C) {
   StringRef Data((const char *)D.data(), D.size());
   uintX_t EntSize = S->getSectionHdr()->sh_entsize;
   this->Header.sh_entsize = EntSize;
-  MutableArrayRef<std::pair<uintX_t, uintX_t>> Offsets = S->Offsets;
 
   // If this is of type string, the contents are null-terminated strings.
   if (this->Header.sh_flags & SHF_STRINGS) {
-    for (unsigned I = 0, N = Offsets.size(); I != N; ++I) {
-      auto &P = Offsets[I];
-      if (P.second == (uintX_t)-1)
-        continue;
-
-      uintX_t Start = P.first;
-      uintX_t End = (I == N - 1) ? Data.size() : Offsets[I + 1].first;
-      StringRef Entry = Data.substr(Start, End - Start);
+    uintX_t Offset = 0;
+    while (!Data.empty()) {
+      size_t End = findNull(Data, EntSize);
+      if (End == StringRef::npos)
+        fatal("string is not null terminated");
+      StringRef Entry = Data.substr(0, End + EntSize);
       uintX_t OutputOffset = Builder.add(Entry);
       if (shouldTailMerge())
         OutputOffset = -1;
-      P.second = OutputOffset;
+      S->Offsets.push_back(std::make_pair(Offset, OutputOffset));
+      uintX_t Size = End + EntSize;
+      Data = Data.substr(Size);
+      Offset += Size;
     }
     return;
   }
 
   // If this is not of type string, every entry has the same size.
-  for (auto &P : Offsets) {
-    if (P.second == (uintX_t)-1)
-      continue;
-    StringRef Entry = Data.substr(P.first, EntSize);
-    P.second = Builder.add(Entry);
+  for (unsigned I = 0, N = Data.size(); I != N; I += EntSize) {
+    StringRef Entry = Data.substr(I, EntSize);
+    size_t OutputOffset = Builder.add(Entry);
+    S->Offsets.push_back(std::make_pair(I, OutputOffset));
   }
 }