[PATCH] D120535: [ELF] Support some PC-relative relocation types for REL format

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: adalava, arichardson, jhibbits.
Herald added subscribers: kbarton, kristof.beyls, nemanjai, emaste.
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ctfconvert seems to use REL-format `.rel.SUNW_dof` for 32-bit architectures.

  Binary file usr/ports/lang/perl5.32/work/perl-5.32.1/dtrace_mini.o matches
  [alfredo.junior at dell-a ~/tmp/llvm-bug]$ readelf -r dtrace_mini.o
  
  Relocation section (.rel.SUNW_dof):
  r_offset r_info   r_type              st_value st_name
  00000184 0000281a R_PPC_REL32         00000000 $dtrace1772974259.Perl_dtrace_probe_load

Support R_PPC_REL32 to fix `ld.lld: error: drti.c:(.SUNW_dof+0x4E4): internal linker error: cannot read addend for relocation R_PPC_REL32`.
While here, add some common relocation types for AArch64, PPC, and PPC64.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120535

Files:
  lld/ELF/Arch/AArch64.cpp
  lld/ELF/Arch/PPC.cpp
  lld/ELF/Arch/PPC64.cpp
  lld/test/ELF/relocation-rel-format.test


Index: lld/test/ELF/relocation-rel-format.test
===================================================================
--- /dev/null
+++ lld/test/ELF/relocation-rel-format.test
@@ -0,0 +1,42 @@
+## Test some relocation types for REL format.
+# RUN: yaml2obj -DMACHINE=AARCH64 -DR0=R_AARCH64_ABS64 -DR1=R_AARCH64_PREL32 -DR2=R_AARCH64_PREL64 %s -o %t.o
+# RUN: ld.lld %t.o -o /dev/null
+# RUN: yaml2obj -DMACHINE=PPC -DBITS=32 -DR0=R_PPC_ADDR32 -DR1=R_PPC_REL32 %s -o %t.o
+# RUN: ld.lld %t.o -o /dev/null
+# RUN: yaml2obj -DMACHINE=PPC64 -DR0=R_PPC64_ADDR64 -DR1=R_PPC64_REL32 -DR2=R_PPC64_REL64 %s -o %t.o
+# RUN: ld.lld %t.o -o /dev/null
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS[[BITS=64]]
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_[[MACHINE]]
+Sections:
+  - Name:  .text
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+    Size:  24
+  - Name:  .data
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_WRITE, SHF_ALLOC ]
+  - Name:  .rel.text
+    Type:  SHT_REL
+    Info:  .text
+    Relocations:
+      - Symbol: .data
+        Type:   [[R0]]
+      - Offset: 8
+        Symbol: .data
+        Type:   [[R1=0]]
+      - Offset: 16
+        Symbol: .data
+        Type:   [[R2=0]]
+Symbols:
+  - Name:    .data
+    Type:    STT_SECTION
+    Section: .data
+  - Name:    _start
+    Section: .text
+    Binding: STB_GLOBAL
+...
Index: lld/ELF/Arch/PPC64.cpp
===================================================================
--- lld/ELF/Arch/PPC64.cpp
+++ lld/ELF/Arch/PPC64.cpp
@@ -1065,6 +1065,11 @@
   switch (type) {
   case R_PPC64_NONE:
     return 0;
+  case R_PPC64_REL32:
+    return SignExtend64<32>(read32(buf));
+  case R_PPC64_ADDR64:
+  case R_PPC64_REL64:
+    return read64(buf);
   default:
     internalLinkerError(getErrorLocation(buf),
                         "cannot read addend for relocation " + toString(type));
Index: lld/ELF/Arch/PPC.cpp
===================================================================
--- lld/ELF/Arch/PPC.cpp
+++ lld/ELF/Arch/PPC.cpp
@@ -280,6 +280,9 @@
   switch (type) {
   case R_PPC_NONE:
     return 0;
+  case R_PPC_ADDR32:
+  case R_PPC_REL32:
+    return SignExtend64<32>(read32(buf));
   default:
     internalLinkerError(getErrorLocation(buf),
                         "cannot read addend for relocation " + toString(type));
Index: lld/ELF/Arch/AArch64.cpp
===================================================================
--- lld/ELF/Arch/AArch64.cpp
+++ lld/ELF/Arch/AArch64.cpp
@@ -198,6 +198,11 @@
     return read64(buf + 8);
   case R_AARCH64_NONE:
     return 0;
+  case R_AARCH64_PREL32:
+    return SignExtend64<32>(read32(buf));
+  case R_AARCH64_ABS64:
+  case R_AARCH64_PREL64:
+    return read64(buf);
   default:
     internalLinkerError(getErrorLocation(buf),
                         "cannot read addend for relocation " + toString(type));


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