Revert "[ELF2] - Implemented rel[a].plt sections"

This reverts commit r249816.

It broke building llvm with lld:

$ ./bin/FileCheck
./bin/FileCheck: error while loading shared libraries: unexpected PLT reloc type 0x06

I think the only thing that is wrong with this patch is that it is too soon.

The plt we create (and its relocs) don't support lazy loading, so they have
to be relocated as ordinary dynamic relocations.

llvm-svn: 249835

6 files changed, 29 insertions, 55 deletions

diff --git a/lld/ELF/OutputSections.cpp b/lld/ELF/OutputSections.cpp
index f0956526ac8..af2e637b6b4 100644
--- a/lld/ELF/OutputSections.cpp
+++ b/lld/ELF/OutputSections.cpp
@@ -48,10 +48,6 @@ template <> RelocationSection<ELF32BE> *Out<ELF32BE>::RelaDyn = nullptr;
 template <> RelocationSection<ELF32LE> *Out<ELF32LE>::RelaDyn = nullptr;
 template <> RelocationSection<ELF64BE> *Out<ELF64BE>::RelaDyn = nullptr;
 template <> RelocationSection<ELF64LE> *Out<ELF64LE>::RelaDyn = nullptr;
-template <> RelocationSection<ELF32BE> *Out<ELF32BE>::RelaPlt = nullptr;
-template <> RelocationSection<ELF32LE> *Out<ELF32LE>::RelaPlt = nullptr;
-template <> RelocationSection<ELF64BE> *Out<ELF64BE>::RelaPlt = nullptr;
-template <> RelocationSection<ELF64LE> *Out<ELF64LE>::RelaPlt = nullptr;
 template <> StringTableSection<false> *Out<ELF32BE>::DynStrTab = nullptr;
 template <> StringTableSection<false> *Out<ELF32LE>::DynStrTab = nullptr;
 template <> StringTableSection<true> *Out<ELF64BE>::DynStrTab = nullptr;
@@ -143,9 +139,10 @@ void PltSection<ELFT>::finalize() {
 }
 
 template <class ELFT>
-RelocationSection<ELFT>::RelocationSection(StringRef Name, bool IsRela)
-    : OutputSectionBase<ELFT::Is64Bits>(Name, IsRela ? llvm::ELF::SHT_RELA
-                                                     : llvm::ELF::SHT_REL,
+RelocationSection<ELFT>::RelocationSection(bool IsRela)
+    : OutputSectionBase<ELFT::Is64Bits>(IsRela ? ".rela.dyn" : ".rel.dyn",
+                                        IsRela ? llvm::ELF::SHT_RELA
+                                               : llvm::ELF::SHT_REL,
                                         llvm::ELF::SHF_ALLOC),
       IsRela(IsRela) {
   this->Header.sh_entsize = IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
@@ -303,13 +300,6 @@ template <class ELFT> void DynamicSection<ELFT>::finalize() {
     ++NumEntries; // DT_RELASZ / DT_RELSZ
     ++NumEntries; // DT_RELAENT / DT_RELENT
   }
-  if (Out<ELFT>::RelaPlt->hasRelocs()) {
-    ++NumEntries; // DT_JMPREL
-    ++NumEntries; // DT_PLTRELSZ
-    ++NumEntries; // DT_PLTGOT
-    ++NumEntries; // DT_PLTREL
-  }
-
   ++NumEntries; // DT_SYMTAB
   ++NumEntries; // DT_SYMENT
   ++NumEntries; // DT_STRTAB
@@ -377,12 +367,6 @@ template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) {
     WriteVal(IsRela ? DT_RELAENT : DT_RELENT,
              IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel));
   }
-  if (Out<ELFT>::RelaPlt->hasRelocs()) {
-    WritePtr(DT_JMPREL, Out<ELFT>::RelaPlt->getVA());
-    WriteVal(DT_PLTRELSZ, Out<ELFT>::RelaPlt->getSize());
-    WritePtr(DT_PLTGOT, Out<ELFT>::Got->getVA());
-    WriteVal(DT_PLTREL, Out<ELFT>::RelaPlt->isRela() ? DT_RELA : DT_REL);
-  }
 
   WritePtr(DT_SYMTAB, Out<ELFT>::DynSymTab->getVA());
   WritePtr(DT_SYMENT, sizeof(Elf_Sym));
diff --git a/lld/ELF/OutputSections.h b/lld/ELF/OutputSections.h
index 7c00aa39d36..8e789566e2f 100644
--- a/lld/ELF/OutputSections.h
+++ b/lld/ELF/OutputSections.h
@@ -171,7 +171,7 @@ class RelocationSection final : public OutputSectionBase<ELFT::Is64Bits> {
   typedef typename llvm::object::ELFFile<ELFT>::uintX_t uintX_t;
 
 public:
-  RelocationSection(StringRef Name, bool IsRela);
+  RelocationSection(bool IsRela);
   void addReloc(const DynamicReloc<ELFT> &Reloc) { Relocs.push_back(Reloc); }
   void finalize() override;
   void writeTo(uint8_t *Buf) override;
@@ -289,7 +289,6 @@ template <class ELFT> struct Out {
   static OutputSection<ELFT> *Bss;
   static PltSection<ELFT> *Plt;
   static RelocationSection<ELFT> *RelaDyn;
-  static RelocationSection<ELFT> *RelaPlt;
   static StringTableSection<ELFT::Is64Bits> *DynStrTab;
   static StringTableSection<ELFT::Is64Bits> *StrTab;
   static SymbolTableSection<ELFT> *DynSymTab;
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index a88a7d43fc7..0688a5bf28b 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -134,11 +134,8 @@ template <class ELFT> static void doWriteResult(SymbolTable *Symtab) {
   Out<ELFT>::DynSymTab = &DynSymTab;
   HashTableSection<ELFT> HashTab;
   Out<ELFT>::HashTab = &HashTab;
-  bool IsRela = Symtab->shouldUseRela();
-  RelocationSection<ELFT> RelaDyn(IsRela ? ".rela.dyn" : ".rel.dyn", IsRela);
+  RelocationSection<ELFT> RelaDyn(Symtab->shouldUseRela());
   Out<ELFT>::RelaDyn = &RelaDyn;
-  RelocationSection<ELFT> RelaPlt(IsRela ? ".rela.plt" : ".rel.plt", IsRela);
-  Out<ELFT>::RelaPlt = &RelaPlt;
   DynamicSection<ELFT> Dynamic(*Symtab);
   Out<ELFT>::Dynamic = &Dynamic;
 
@@ -236,15 +233,11 @@ void Writer<ELFT>::scanRelocs(
         Out<ELFT>::Got->addEntry(Body);
       }
     }
-
-    bool CanBePreempted = canBePreempted(Body);
-    if (CanBePreempted)
+    if (canBePreempted(Body)) {
       Body->setUsedInDynamicReloc();
-    if (CanBePreempted || (Config->Shared && !Target->isRelRelative(Type))) {
-      if (Body && Body->isInPlt())
-        Out<ELFT>::RelaPlt->addReloc({C, RI});
-      else
-        Out<ELFT>::RelaDyn->addReloc({C, RI});
+      Out<ELFT>::RelaDyn->addReloc({C, RI});
+    } else if (Config->Shared && !Target->isRelRelative(Type)) {
+      Out<ELFT>::RelaDyn->addReloc({C, RI});
     }
   }
 }
@@ -473,8 +466,6 @@ template <class ELFT> void Writer<ELFT>::createSections() {
     OutputSections.push_back(Out<ELFT>::DynStrTab);
     if (Out<ELFT>::RelaDyn->hasRelocs())
       OutputSections.push_back(Out<ELFT>::RelaDyn);
-    if (Out<ELFT>::RelaPlt->hasRelocs())
-      OutputSections.push_back(Out<ELFT>::RelaPlt);
   }
   if (!Out<ELFT>::Got->empty())
     OutputSections.push_back(Out<ELFT>::Got);
diff --git a/lld/test/elf2/plt-i686.s b/lld/test/elf2/plt-i686.s
index 9eb9401c90d..006851ffd2d 100644
--- a/lld/test/elf2/plt-i686.s
+++ b/lld/test/elf2/plt-i686.s
@@ -20,9 +20,9 @@
 // CHECK-NEXT: AddressAlignment: 16
 
 // CHECK:      Relocations [
-// CHECK-NEXT:   Section ({{.*}}) .rel.plt {
-// CHECK-NEXT:     0x13058 R_386_GLOB_DAT bar 0x0
-// CHECK-NEXT:     0x1305C R_386_GLOB_DAT zed 0x0
+// CHECK-NEXT:   Section ({{.*}}) .rel.dyn {
+// CHECK-NEXT:     0x13050 R_386_GLOB_DAT bar 0x0
+// CHECK-NEXT:     0x13054 R_386_GLOB_DAT zed 0x0
 // CHECK-NEXT:   }
 // CHECK-NEXT: ]
 
@@ -38,15 +38,15 @@
 // DISASM-NEXT:   12005:  e9 06 00 00 00  jmp  6
 // DISASM-NEXT:   1200a:  e9 09 00 00 00  jmp  9
 
-// 0x13058 = 77912
-// 0x1305C = 77916
+// 0x13050 = 77904
+// 0x13054 = 77908
 
 // DISASM:      Disassembly of section .plt:
 // DISASM-NEXT: .plt:
-// DISASM-NEXT:   12010:  ff 25 {{.*}}       jmpl *77912
+// DISASM-NEXT:   12010:  ff 25 {{.*}}       jmpl *77904
 // DISASM-NEXT:   12016:  90                 nop
 // DISASM-NEXT:   12017:  90                 nop
-// DISASM-NEXT:   12018:  ff 25 {{.*}}       jmpl *77916
+// DISASM-NEXT:   12018:  ff 25 {{.*}}       jmpl *77908
 // DISASM-NEXT:   1201e:  90                 nop
 // DISASM-NEXT:   1201f:  90                 nop
 
diff --git a/lld/test/elf2/plt.s b/lld/test/elf2/plt.s
index 1176956abe1..bf54ca23683 100644
--- a/lld/test/elf2/plt.s
+++ b/lld/test/elf2/plt.s
@@ -20,10 +20,10 @@
 // CHECK-NEXT: AddressAlignment: 16
 
 // CHECK:      Relocations [
-// CHECK-NEXT:   Section ({{.*}}) .rela.plt {
-// CHECK-NEXT:     0x30B0 R_X86_64_GLOB_DAT bar 0x0
-// CHECK-NEXT:     0x30B8 R_X86_64_GLOB_DAT zed 0x0
-// CHECK-NEXT:     0x30C0 R_X86_64_GLOB_DAT _start 0x0
+// CHECK-NEXT:   Section ({{.*}}) .rela.dyn {
+// CHECK-NEXT:     0x30A0 R_X86_64_GLOB_DAT bar 0x0
+// CHECK-NEXT:     0x30A8 R_X86_64_GLOB_DAT zed 0x0
+// CHECK-NEXT:     0x30B0 R_X86_64_GLOB_DAT _start 0x0
 // CHECK-NEXT:   }
 // CHECK-NEXT: ]
 
@@ -39,15 +39,15 @@
 // DISASM-NEXT:   2005:  e9 {{.*}}       jmp  22
 // DISASM-NEXT:   200a:  e9 {{.*}}       jmp  25
 
-// 0x30B0 - 0x2026  = 4234
-// 0x30B8 - 0x202e  = 4234
+// 0x130A0 - 0x12026  = 4218
+// 0x130A8 - 0x1202e  = 4218
 
 // DISASM:      Disassembly of section .plt:
 // DISASM-NEXT: .plt:
-// DISASM-NEXT:   2020:  ff 25 {{.*}}       jmpq *4234(%rip)
+// DISASM-NEXT:   2020:  ff 25 {{.*}}       jmpq *4218(%rip)
 // DISASM-NEXT:   2026:  90                 nop
 // DISASM-NEXT:   2027:  90                 nop
-// DISASM-NEXT:   2028:  ff 25 {{.*}}       jmpq *4234(%rip)
+// DISASM-NEXT:   2028:  ff 25 {{.*}}       jmpq *4218(%rip)
 // DISASM-NEXT:   202e:  90                 nop
 // DISASM-NEXT:   202f:  90                 nop
 
diff --git a/lld/test/elf2/relocation.s b/lld/test/elf2/relocation.s
index e4d90ea7e87..35f7e305881 100644
--- a/lld/test/elf2/relocation.s
+++ b/lld/test/elf2/relocation.s
@@ -22,7 +22,7 @@
 // SEC-NEXT:     SHF_ALLOC
 // SEC-NEXT:     SHF_WRITE
 // SEC-NEXT:   ]
-// SEC-NEXT:   Address: 0x130E0
+// SEC-NEXT:   Address: 0x130A0
 // SEC-NEXT:   Offset:
 // SEC-NEXT:   Size: 16
 // SEC-NEXT:   Link: 0
@@ -93,7 +93,7 @@ R_X86_64_64:
 R_X86_64_GOTPCREL:
  .long zed@gotpcrel
 
-// 0x130E8 - 0x11008 = 8416
-// 8416 = 0xE0200000   in little endian
+// 0x130A8 - 0x11008 = 8352
+// 8352 = 0x80200000   in little endian
 // CHECK:      Contents of section .R_X86_64_GOTPCREL
-// CHECK-NEXT:   11008 e0200000
+// CHECK-NEXT:   11008 a0200000