Create _end symbol even if a .so defines it.

The freebsd sbrk implementation uses _end to find the initial value of
brk, so it has to be defined in the main binary.

This should fix the emacs build.

llvm-svn: 292512

lld/ELF/SymbolTable.cpp

@@ -140,7 +140,7 @@ template <class ELFT>
 DefinedRegular<ELFT> *SymbolTable<ELFT>::addIgnored(StringRef Name,
                                                     uint8_t Visibility) {
   SymbolBody *S = find(Name);
-  if (!S || !S->isUndefined())
+  if (!S || S->isInCurrentDSO())
     return nullptr;
   return addAbsolute(Name, Visibility);
 }

lld/test/ELF/Inputs/resolution-end.s

@@ -0,0 +1,2 @@
+.data
+        .quad _end

lld/test/ELF/resolution-end.s

@@ -0,0 +1,39 @@
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t1.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/resolution-end.s -o %t2.o
+# RUN: ld.lld -shared -o %t2.so %t2.o
+# RUN: ld.lld %t1.o %t2.so -o %t
+# RUN: llvm-readobj -t -s -section-data  %t | FileCheck %s
+# REQUIRES: x86
+
+# Test that we resolve _end to the this executable.
+
+# CHECK:      Name: .text
+# CHECK-NEXT: Type: SHT_PROGBITS
+# CHECK-NEXT: Flags [
+# CHECK-NEXT:   SHF_ALLOC
+# CHECK-NEXT:   SHF_EXECINSTR
+# CHECK-NEXT: ]
+# CHECK-NEXT: Address:
+# CHECK-NEXT: Offset:
+# CHECK-NEXT: Size:
+# CHECK-NEXT: Link:
+# CHECK-NEXT: Info:
+# CHECK-NEXT: AddressAlignment:
+# CHECK-NEXT: EntrySize:
+# CHECK-NEXT: SectionData (
+# CHECK-NEXT:   0000: 80202000 00000000
+# CHECK-NEXT: )
+
+# CHECK:      Symbol {
+# CHECK:        Name: _end
+# CHECK-NEXT:   Value: 0x202080
+# CHECK-NEXT:   Size:
+# CHECK-NEXT:   Binding: Global
+# CHECK-NEXT:   Type:
+# CHECK-NEXT:   Other:
+# CHECK-NEXT:   Section:
+# CHECK-NEXT: }
+
+.global _start
+_start:
+.quad _end