[Mips] Write _DYNAMIC symbol on MIPS targets

llvm-svn: 234925

lld/lib/ReaderWriter/ELF/Mips/MipsELFWriters.h

@@ -16,6 +16,13 @@ namespace elf {
 
 template <class ELFT> class MipsTargetLayout;
 
+class MipsDynamicAtom : public DynamicAtom {
+public:
+  MipsDynamicAtom(const File &f) : DynamicAtom(f) {}
+
+  ContentPermissions permissions() const override { return permR__; }
+};
+
 template <typename ELFT> class MipsELFWriter {
 public:
   MipsELFWriter(MipsLinkingContext &ctx, MipsTargetLayout<ELFT> &targetLayout)
@@ -54,6 +61,7 @@ public:
       file->addAbsoluteAtom("_gp");
       file->addAbsoluteAtom("_gp_disp");
       file->addAbsoluteAtom("__gnu_local_gp");
+      file->addAtom(*new (file->allocator()) MipsDynamicAtom(*file));
     }
     return file;
   }

lld/test/elf/Mips/dynamic-sym.test

@@ -0,0 +1,41 @@
+# Check _DYNAMIC symbol's value
+#
+# RUN: yaml2obj -format=elf %s > %t.o
+# RUN: lld -flavor gnu -target mipsel -shared -e T0 -o %t.so %t.o
+# RUN: llvm-objdump -h -t %t.so | FileCheck -check-prefix=SHARED %s
+
+# SHARED: Sections:
+# SHARED: Idx Name      Size     Address          Type
+# SHARED:   5 .dynamic  00000068 00000000000000d4
+
+# SHARED: SYMBOL TABLE:
+# SHARED: 000000d4 g  .dynamic  00000000 _DYNAMIC
+
+# RUN: lld -flavor gnu -target mipsel -e main -e T0 -o %t.exe %t.o
+# RUN: llvm-objdump -h -t %t.exe | FileCheck -check-prefix=EXE %s
+
+# EXE: Sections:
+# EXE: Idx Name         Size     Address          Type
+# EXE:   6 .dynamic     00000068 0000000000400114
+
+# EXE: SYMBOL TABLE:
+# EXE: 00400114 g     .dynamic  00000000 _DYNAMIC
+
+FileHeader:
+  Class:    ELFCLASS32
+  Data:     ELFDATA2LSB
+  Type:     ET_REL
+  Machine:  EM_MIPS
+  Flags:    [EF_MIPS_CPIC, EF_MIPS_ABI_O32, EF_MIPS_ARCH_32]
+
+Sections:
+  - Name:          .text
+    Type:          SHT_PROGBITS
+    Flags:         [SHF_ALLOC, SHF_EXECINSTR]
+    AddressAlign:  0x10
+    Size:          0x04
+
+Symbols:
+  Global:
+    - Name:     T0
+      Section:  .text