[llvm] r339799 - llvm-readobj: Fix addend in relocations for android packed format

[Peter Collingbourne via llvm-commits]

Author: pcc
Date: Wed Aug 15 10:58:22 2018
New Revision: 339799

URL: http://llvm.org/viewvc/llvm-project?rev=339799&view=rev
Log:
llvm-readobj: Fix addend in relocations for android packed format

If a relocation group doesn't have the RELOCATION_GROUP_HAS_ADDEND_FLAG set, then this implies the group's addend equals zero.
In this case android packed format won't encode an explicit addend delta, instead we need to set Addend, the "previous addend" variable, to zero by ourself.

Patch by Yi-Yo Chiang!

Differential Revision: https://reviews.llvm.org/D50601

Modified:
    llvm/trunk/lib/Object/ELF.cpp
    llvm/trunk/test/tools/llvm-readobj/elf-packed-relocs.test

Modified: llvm/trunk/lib/Object/ELF.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/ELF.cpp?rev=339799&r1=339798&r2=339799&view=diff
==============================================================================
--- llvm/trunk/lib/Object/ELF.cpp (original)
+++ llvm/trunk/lib/Object/ELF.cpp Wed Aug 15 10:58:22 2018
@@ -393,20 +393,17 @@ ELFFile<ELFT>::android_relas(const Elf_S
     if (GroupedByAddend && GroupHasAddend)
       Addend += ReadSLEB();
 
+    if (!GroupHasAddend)
+      Addend = 0;
+
     for (uint64_t I = 0; I != NumRelocsInGroup; ++I) {
       Elf_Rela R;
       Offset += GroupedByOffsetDelta ? GroupOffsetDelta : ReadSLEB();
       R.r_offset = Offset;
       R.r_info = GroupedByInfo ? GroupRInfo : ReadSLEB();
-
-      if (GroupHasAddend) {
-        if (!GroupedByAddend)
-          Addend += ReadSLEB();
-        R.r_addend = Addend;
-      } else {
-        R.r_addend = 0;
-      }
-
+      if (GroupHasAddend && !GroupedByAddend)
+        Addend += ReadSLEB();
+      R.r_addend = Addend;
       Relocs.push_back(R);
 
       if (ErrStr)

Modified: llvm/trunk/test/tools/llvm-readobj/elf-packed-relocs.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-readobj/elf-packed-relocs.test?rev=339799&r1=339798&r2=339799&view=diff
==============================================================================
--- llvm/trunk/test/tools/llvm-readobj/elf-packed-relocs.test (original)
+++ llvm/trunk/test/tools/llvm-readobj/elf-packed-relocs.test Wed Aug 15 10:58:22 2018
@@ -94,3 +94,45 @@ Symbols:
     - Name:            sym1
     - Name:            sym2
 ...
+
+# RUN: yaml2obj -docnum 3 %s | llvm-readobj -elf-output-style=LLVM -relocations - | FileCheck --check-prefix=LLVM3 %s
+#
+# LLVM3:      Section (1) .rela.dyn {
+# LLVM3-NEXT:   0x1100 R_X86_64_RELATIVE - 0x0
+# LLVM3-NEXT:   0x1180 R_X86_64_RELATIVE - 0x8
+# LLVM3-NEXT:   0x1200 R_X86_64_64 sym1 0x0
+# LLVM3-NEXT:   0x1208 R_X86_64_64 sym2 0x0
+# LLVM3-NEXT:   0x1210 R_X86_64_64 sym1 0x0
+# LLVM3-NEXT:   0x1218 R_X86_64_64 sym2 0x8
+# LLVM3-NEXT: }
+
+# RUN: yaml2obj -docnum 3 %s | llvm-readobj -elf-output-style=GNU -relocations - | FileCheck --check-prefix=GNU3 %s
+# GNU3:      Relocation section '.rela.dyn' at offset 0x180 contains 6 entries:
+# GNU3: 0000000000001100  0000000000000008 R_X86_64_RELATIVE                 0
+# GNU3-NEXT: 0000000000001180  0000000000000008 R_X86_64_RELATIVE                 8
+# GNU3-NEXT: 0000000000001200  0000000100000001 R_X86_64_64            0000000000000000 sym1 + 0
+# GNU3-NEXT: 0000000000001208  0000000200000001 R_X86_64_64            0000000000000000 sym2 + 0
+# GNU3-NEXT: 0000000000001210  0000000100000001 R_X86_64_64            0000000000000000 sym1 + 0
+# GNU3-NEXT: 0000000000001218  0000000200000001 R_X86_64_64            0000000000000000 sym2 + 8
+
+# elf-packed-relocs3.s
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_DYN
+  Machine:         EM_X86_64
+  Entry:           0x0000000000001000
+Sections:
+  - Name:            .rela.dyn
+    Type:            SHT_ANDROID_RELA
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x00000000000001C8
+    Link:            .symtab
+    AddressAlign:    0x0000000000000001
+    Content:         415053320680200208800208008001080802008001818080801008818080802002080881808080100008818080802008
+Symbols:
+  Global:
+    - Name:            sym1
+    - Name:            sym2
+...