[lld] 3822e3d - [lld-macho] Fix bug in handling unwind info from ld -r

[Vy Nguyen via llvm-commits]

Author: Vy Nguyen
Date: 2021-07-09T22:44:51-04:00
New Revision: 3822e3d5b049a23ac8ba78dd73767a490b678bd3

URL: https://github.com/llvm/llvm-project/commit/3822e3d5b049a23ac8ba78dd73767a490b678bd3
DIFF: https://github.com/llvm/llvm-project/commit/3822e3d5b049a23ac8ba78dd73767a490b678bd3.diff

LOG: [lld-macho] Fix bug in handling unwind info from ld -r
Two changess:
- Drop assertions that all symbols are in GOT
- Set allEntriesAreOmitted correctly

Related bug: 50812

Differential Revision: https://reviews.llvm.org/D105364

Added: 
    lld/test/MachO/relocs-syms-not-in-got.s

Modified: 
    lld/MachO/UnwindInfoSection.cpp

Removed: 
    


################################################################################
diff  --git a/lld/MachO/UnwindInfoSection.cpp b/lld/MachO/UnwindInfoSection.cpp
index 6bd07c42af819..81a5064558aaa 100644
--- a/lld/MachO/UnwindInfoSection.cpp
+++ b/lld/MachO/UnwindInfoSection.cpp
@@ -167,9 +167,14 @@ void UnwindInfoSectionImpl<Ptr>::prepareRelocations(ConcatInputSection *isec) {
     assert(target->hasAttr(r.type, RelocAttrBits::UNSIGNED));
 
     if (r.offset % sizeof(CompactUnwindEntry<Ptr>) == 0) {
-      if (auto *referentIsec = r.referent.dyn_cast<InputSection *>())
-        if (!cast<ConcatInputSection>(referentIsec)->shouldOmitFromOutput())
-          allEntriesAreOmitted = false;
+      InputSection *referentIsec;
+      if (auto *isec = r.referent.dyn_cast<InputSection *>())
+        referentIsec = isec;
+      else
+        referentIsec = cast<Defined>(r.referent.dyn_cast<Symbol *>())->isec;
+
+      if (!cast<ConcatInputSection>(referentIsec)->shouldOmitFromOutput())
+        allEntriesAreOmitted = false;
       continue;
     }
 
@@ -257,7 +262,6 @@ relocateCompactUnwind(ConcatOutputSection *compactUnwindSection,
       uint64_t referentVA = TombstoneValue<Ptr>;
       if (auto *referentSym = r.referent.dyn_cast<Symbol *>()) {
         if (!isa<Undefined>(referentSym)) {
-          assert(referentSym->isInGot());
           if (auto *defined = dyn_cast<Defined>(referentSym))
             checkTextSegment(defined->isec);
           // At this point in the link, we may not yet know the final address of

diff  --git a/lld/test/MachO/relocs-syms-not-in-got.s b/lld/test/MachO/relocs-syms-not-in-got.s
new file mode 100644
index 0000000000000..20a08152b36e9
--- /dev/null
+++ b/lld/test/MachO/relocs-syms-not-in-got.s
@@ -0,0 +1,101 @@
+# REQUIRES: x86
+## These yaml files were  from an object file produced with 'ld -r', specifically:
+##
+##  // foo.s
+## .text
+## .globl _main
+## _main:
+##   .cfi_startproc
+##   .cfi_def_cfa_offset 16
+##   .cfi_endproc
+##   nop
+##
+## llvm-mc -filetype=obj -triple=x86_64-apple-macos10.15 -o foo1.o foo.s
+## ld -r -o foo.o foo1.o
+
+
+# RUN: rm -rf %t; mkdir -p %t
+# RUN: yaml2obj %s -o %t/foo.o
+# RUN: %lld -o %t/a.out %t/foo.o
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000001
+  ncmds:           2
+  sizeofcmds:      384
+  flags:           0x00000000
+  reserved:        0x00000000
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         312
+    segname:         ''
+    vmaddr:          0
+    vmsize:          64
+    fileoff:         448
+    filesize:        64
+    maxprot:         7
+    initprot:        7
+    nsects:          2
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x0000000000000000
+        size:            1
+        offset:          0x000001C0
+        align:           0
+        reloff:          0x00000000
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+        content:         '90'
+      - sectname:        __compact_unwind
+        segname:         __LD
+        addr:            0x0000000000000020
+        size:            32
+        offset:          0x000001E0
+        align:           3
+        reloff:          0x00000200
+        nreloc:          1
+        flags:           0x02000000
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+        content:         '0000000000000000010000000000020200000000000000000000000000000000'
+        relocations:
+          - address:         0x00000000
+            symbolnum:       1
+            pcrel:           false
+            length:          3
+            extern:          true
+            type:            0
+            scattered:       false
+            value:           0
+  - cmd:             LC_SYMTAB
+    cmdsize:         24
+    symoff:          520
+    nsyms:           2
+    stroff:          552
+    strsize:         24
+LinkEditData:
+  NameList:
+    - n_strx:          8
+      n_type:          0x0E
+      n_sect:          2
+      n_desc:          0
+      n_value:         8
+    - n_strx:          2
+      n_type:          0x0F
+      n_sect:          1
+      n_desc:          32
+      n_value:         0
+  StringTable:
+    - ' '
+    - _main
+
+...