[llvm-branch-commits] [lld] cdd8cca - [ELF] Support some absolute/PC-relative relocation types for REL format

[Fangrui Song via llvm-branch-commits]

Author: Fangrui Song
Date: 2022-02-25T19:42:17Z
New Revision: cdd8cca0c33c5392d9247c8aea036bfbb471c971

URL: https://github.com/llvm/llvm-project/commit/cdd8cca0c33c5392d9247c8aea036bfbb471c971
DIFF: https://github.com/llvm/llvm-project/commit/cdd8cca0c33c5392d9247c8aea036bfbb471c971.diff

LOG: [ELF] Support some absolute/PC-relative relocation types for REL format

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.
We perform minimum tests.

Reviewed By: adalava, arichardson

Differential Revision: https://reviews.llvm.org/D120535

(cherry picked from commit 767e64fc11d7734843ec5bb0bd3f7330541bb1a6)

Added: 
    lld/test/ELF/relocation-rel-format.test

Modified: 
    lld/ELF/Arch/AArch64.cpp
    lld/ELF/Arch/PPC.cpp
    lld/ELF/Arch/PPC64.cpp

Removed: 
    


################################################################################
diff  --git a/lld/ELF/Arch/AArch64.cpp b/lld/ELF/Arch/AArch64.cpp
index 9e857d5906845..add819ff5a802 100644
--- a/lld/ELF/Arch/AArch64.cpp
+++ b/lld/ELF/Arch/AArch64.cpp
@@ -199,6 +199,11 @@ int64_t AArch64::getImplicitAddend(const uint8_t *buf, RelType type) const {
     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));

diff  --git a/lld/ELF/Arch/PPC.cpp b/lld/ELF/Arch/PPC.cpp
index 315ac7df608d0..47c31e3a3b943 100644
--- a/lld/ELF/Arch/PPC.cpp
+++ b/lld/ELF/Arch/PPC.cpp
@@ -280,6 +280,9 @@ int64_t PPC::getImplicitAddend(const uint8_t *buf, RelType type) const {
   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));

diff  --git a/lld/ELF/Arch/PPC64.cpp b/lld/ELF/Arch/PPC64.cpp
index 7d051c43af0d3..871e19262ae77 100644
--- a/lld/ELF/Arch/PPC64.cpp
+++ b/lld/ELF/Arch/PPC64.cpp
@@ -1064,6 +1064,11 @@ int64_t PPC64::getImplicitAddend(const uint8_t *buf, RelType type) const {
   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));

diff  --git a/lld/test/ELF/relocation-rel-format.test b/lld/test/ELF/relocation-rel-format.test
new file mode 100644
index 0000000000000..df38f8f7daf15
--- /dev/null
+++ b/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
+...