Revert "[ELF] Suppress "STT_SECTION symbol should be defined" on .eh_frame, .debug*, .zdebug* and .gcc_except_table"

This reverts commit dcba4828a9.

This commit builds on  dcba4828a9 which breaks the
multi-staged PowerPC buildbot.

llvm-svn: 362738

lld/ELF/InputSection.cpp

@@ -412,8 +412,7 @@ void InputSection::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) {
 
   for (const RelTy &Rel : Rels) {
     RelType Type = Rel.getType(Config->IsMips64EL);
-    const ObjFile<ELFT> *File = getFile<ELFT>();
-    Symbol &Sym = File->getRelocTargetSym(Rel);
+    Symbol &Sym = getFile<ELFT>()->getRelocTargetSym(Rel);
 
     auto *P = reinterpret_cast<typename ELFT::Rela *>(Buf);
     Buf += sizeof(RelTy);
@@ -436,20 +435,10 @@ void InputSection::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) {
       // .eh_frame is horribly special and can reference discarded sections. To
       // avoid having to parse and recreate .eh_frame, we just replace any
       // relocation in it pointing to discarded sections with R_*_NONE, which
-      // hopefully creates a frame that is ignored at runtime. Also, don't warn
-      // on .gcc_except_table and debug sections.
+      // hopefully creates a frame that is ignored at runtime.
       auto *D = dyn_cast<Defined>(&Sym);
       if (!D) {
-        if (!Sec->Name.startswith(".debug") &&
-            !Sec->Name.startswith(".zdebug") && Sec->Name != ".eh_frame" &&
-            Sec->Name != ".gcc_except_table") {
-          uint32_t SecIdx = cast<Undefined>(Sym).DiscardedSecIdx;
-          Elf_Shdr_Impl<ELFT> Sec =
-              CHECK(File->getObj().sections(), File)[SecIdx];
-          warn("relocation refers to a discarded section: " +
-               CHECK(File->getObj().getSectionName(&Sec), File) +
-               "\n>>> referenced by " + getObjMsg(P->r_offset));
-        }
+        warn("STT_SECTION symbol should be defined");
         P->setSymbolAndType(0, 0, false);
         continue;
       }

lld/test/ELF/Inputs/comdat-discarded-reloc.s

@@ -1,8 +1,6 @@
-.global bar, _start
+.section .text.bar1,"aG",@progbits,group,comdat
 
-.section .text.foo,"aG",@progbits,group,comdat
-
-.section .text
-_start:
- .quad .text.foo
- .quad bar
+.section .text.bar2
+.global bar
+bar:
+ .quad .text.bar1

lld/test/ELF/comdat-discarded-reloc.s

@@ -1,42 +1,17 @@
 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/comdat-discarded-reloc.s -o %t2.o
-# RUN: ld.lld -gc-sections --noinhibit-exec %t2.o %t.o -o /dev/null
-# RUN: ld.lld -r %t2.o %t.o -o %t 2>&1 | FileCheck --check-prefix=WARN %s
-# RUN: llvm-readobj -r %t | FileCheck --check-prefix=RELOC %s
+# RUN: ld.lld -gc-sections --noinhibit-exec %t.o %t2.o -o /dev/null
 
 ## ELF spec doesn't allow a relocation to point to a deduplicated
 ## COMDAT section. Unfortunately this happens in practice (e.g. .eh_frame)
 ## Test case checks we do not crash.
 
-# WARN: warning: relocation refers to a discarded section: .text.bar1
-# WARN-NEXT: >>> referenced by {{.*}}.o:(.rela.text.bar2+0x0)
-# WARN-NOT: warning
+.global bar, _start
 
-# RELOC:      .rela.eh_frame {
-# RELOC-NEXT:   R_X86_64_NONE
-# RELOC-NEXT: }
-# RELOC-NEXT: .rela.debug_foo {
-# RELOC-NEXT:   R_X86_64_NONE
-# RELOC-NEXT: }
-# RELOC-NEXT: .rela.gcc_except_table {
-# RELOC-NEXT:   R_X86_64_NONE
-# RELOC-NEXT: }
+.section .text.foo,"aG",@progbits,group,comdat
 
-.section .text.bar1,"aG",@progbits,group,comdat
-
-## .text.bar1 in this file is discarded. Warn on the relocation.
-.section .text.bar2,"ax"
-.globl bar
-bar:
-  .quad .text.bar1
-
-## Don't warn on .eh_frame, .debug*, .zdebug*, or .gcc_except_table
-.section .eh_frame,"a"
-  .quad .text.bar1
-
-.section .debug_foo
-  .quad .text.bar1
-
-.section .gcc_except_table,"a"
-  .quad .text.bar1
+.section .text
+_start:
+ .quad .text.foo
+ .quad bar

lld/test/ELF/invalid-undef-section-symbol.test

@@ -0,0 +1,26 @@
+# RUN: yaml2obj %s -o %t.o
+# RUN: not ld.lld -r --fatal-warnings %t.o -o /dev/null 2>&1 | FileCheck %s
+
+# We used to crash at this.
+# CHECK: STT_SECTION symbol should be defined
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+  - Name:            .rela.text
+    Type:            SHT_RELA
+    AddressAlign:    0x0000000000000008
+    Info:            .text
+    Relocations:
+      - Offset:          0x0000000000000000
+        Symbol:          .text
+        Type:            R_X86_64_NONE
+Symbols:
+  - Name:            .text
+    Type:            STT_SECTION

lld/test/ELF/relocatable-eh-frame.s

@@ -0,0 +1,21 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: ld.lld -r %t.o %t.o -o %t 2>&1 | FileCheck --check-prefix=WARN %s
+# RUN: llvm-readobj -r %t | FileCheck %s
+# RUN: ld.lld %t -o %t.so -shared
+# RUN: llvm-objdump -h %t.so | FileCheck --check-prefix=DSO %s
+
+# WARN: STT_SECTION symbol should be defined
+
+# DSO: .eh_frame     00000034
+
+# CHECK:      Relocations [
+# CHECK-NEXT:   Section ({{.*}}) .rela.eh_frame {
+# CHECK-NEXT:     0x20 R_X86_64_PC32 .foo 0x0
+# CHECK-NEXT:     0x50 R_X86_64_NONE - 0x0
+# CHECK-NEXT:   }
+# CHECK-NEXT: ]
+
+.section .foo,"aG",@progbits,bar,comdat
+.cfi_startproc
+.cfi_endproc