[lld-macho] Ignore debug symbols while preparing relocations.

Details: see https://bugs.llvm.org/show_bug.cgi?id=50812

Differential Revision: https://reviews.llvm.org/D105210

lld/MachO/InputFiles.cpp

@@ -592,6 +592,12 @@ void ObjFile::parseSymbols(ArrayRef<typename LP::section> sectionHeaders,
   symbols.resize(nList.size());
   for (uint32_t i = 0; i < nList.size(); ++i) {
     const NList &sym = nList[i];
+
+    // Ignore debug symbols for now.
+    // FIXME: may need special handling.
+    if (sym.n_type & N_STAB)
+      continue;
+
     StringRef name = strtab + sym.n_strx;
     if ((sym.n_type & N_TYPE) == N_SECT) {
       SubsectionMap &subsecMap = subsections[sym.n_sect - 1];

lld/test/MachO/bug_50812.s

@@ -0,0 +1,126 @@
+# REQUIRES: x86
+## FIXME: This yaml is from an object file produced with 'ld -r'
+##        Replace this with "normal" .s test format once lld supports `-r`
+
+# RUN: yaml2obj %s -o %t.o
+# RUN: %lld -lSystem -platform_version macos 11.3 11.0 -arch x86_64 %t.o
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000001
+  ncmds:           2
+  sizeofcmds:      384
+  flags:           0x00002000
+  reserved:        0x00000000
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         312
+    segname:         ''
+    vmaddr:          0
+    vmsize:          120
+    fileoff:         448
+    filesize:        120
+    maxprot:         7
+    initprot:        7
+    nsects:          2
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x0000000000000000
+        size:            18
+        offset:          0x000001C0
+        align:           4
+        reloff:          0x00000000
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+        content:         554889E5C745FC00000000B8010000005DC3
+      - sectname:        __eh_frame
+        segname:         __TEXT
+        addr:            0x0000000000000018
+        size:            64
+        offset:          0x000001D8
+        align:           3
+        reloff:          0x00000238
+        nreloc:          4
+        flags:           0x00000000
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+        content:         1400000000000000017A520001781001100C0708900100002400000004000000F8FFFFFFFFFFFFFF120000000000000000410E108602430D0600000000000000
+        relocations:
+          - address:         0x0000001C
+            symbolnum:       0
+            pcrel:           false
+            length:          2
+            extern:          true
+            type:            5
+            scattered:       false
+            value:           0
+          - address:         0x0000001C
+            symbolnum:       1
+            pcrel:           false
+            length:          2
+            extern:          true
+            type:            0
+            scattered:       false
+            value:           0
+          - address:         0x00000020
+            symbolnum:       1
+            pcrel:           false
+            length:          3
+            extern:          true
+            type:            5
+            scattered:       false
+            value:           0
+          - address:         0x00000020
+            symbolnum:       10
+            pcrel:           false
+            length:          3
+            extern:          true
+            type:            0
+            scattered:       false
+            value:           0
+  - cmd:             LC_SYMTAB
+    cmdsize:         24
+    symoff:          608
+    nsyms:           11
+    stroff:          784
+    strsize:         72
+LinkEditData:
+  NameList:
+    - n_strx:          8      ## N_STAB sym (in got)
+      n_type:          0x0E
+      n_sect:          2
+      n_desc:          0
+      n_value:         24
+    - n_strx:          18
+      n_type:          0x0E
+      n_sect:          2
+      n_desc:          0
+      n_value:         48
+    - n_strx:          1
+      n_type:          0x4E
+      n_sect:          1
+      n_desc:          0
+      n_value:         18
+    - n_strx:          2          ## _main
+      n_type:          0x0F
+      n_sect:          1
+      n_desc:          0
+      n_value:         0
+  StringTable:
+    - ' '
+    - _main
+    - EH_Frame1
+    - func.eh
+    - '/Users/vyng/'
+    - test.cc
+    - '/Users/vyng/test.o'
+    - _main
+...