[AARCH64] Switch relocations R_AARCH64_TLS_TPREL64 and R_AARCH64_DTPMOD64

The ELF for the Arm 64-bit Architecture document originally specified
R_AARCH64_TLS_DTPREL64 = 0x404
R_AARCH64_TLS_DTPMOD64 = 0x405

LLVM correctly followed the document. Unfortunately in binutils these
two codes were reversed:
R_AARCH64_TLS_DTPMOD64 = 0x404
R_AARCH64_TLS_DTPREL64 = 0x405
Given that binaries had shipped this change has become the defacto standard
interpretation of these relocation codes for any toolchain that wanted to
remain compatible with GNU.

To recognize this the latest version of the ABI document has renamed
the relocations to R_AARCH64_TLS_IMPDEF1 and R_AARCH64_TLS_IMPDEF2
permitting a toolchain to choose between the two relocation types, and
recommending that toolchains follow the GNU interpretation for maximum
compatibility.

Given that upstream llvm has never implemented the standard TLS model for
AArch64 so we have no binary legacy, synchronize with GCC so that we don't
create incompatible objects in the future. So far the only visible change
is in llvm-readobj as it can decode these relocations. Tthis change will
mean that llvm-readobj decodes the same way as GNU readelf.

fixes PR40507

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@367437 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/BinaryFormat/ELFRelocs/AArch64.def b/include/llvm/BinaryFormat/ELFRelocs/AArch64.def
index 4afcd7d1f09394ac57547125cb7a22d7af8a89ab..c8364133e31faf05bd9ca60064ef23c395b99eb2 100644 (file)
--- a/include/llvm/BinaryFormat/ELFRelocs/AArch64.def
+++ b/include/llvm/BinaryFormat/ELFRelocs/AArch64.def
@@ -124,8 +124,11 @@ ELF_RELOC(R_AARCH64_COPY,                            0x400)
 ELF_RELOC(R_AARCH64_GLOB_DAT,                        0x401)
 ELF_RELOC(R_AARCH64_JUMP_SLOT,                       0x402)
 ELF_RELOC(R_AARCH64_RELATIVE,                        0x403)
-ELF_RELOC(R_AARCH64_TLS_DTPREL64,                    0x404)
-ELF_RELOC(R_AARCH64_TLS_DTPMOD64,                    0x405)
+// 0x404 and 0x405 are now R_AARCH64_TLS_IMPDEF1 and R_AARCH64_TLS_IMPDEF2
+// We follow GNU and define TLS_IMPDEF1 as TLS_DTPMOD64 and TLS_IMPDEF2 as
+// TLS_DTPREL64
+ELF_RELOC(R_AARCH64_TLS_DTPMOD64,                    0x404)
+ELF_RELOC(R_AARCH64_TLS_DTPREL64,                    0x405)
 ELF_RELOC(R_AARCH64_TLS_TPREL64,                     0x406)
 ELF_RELOC(R_AARCH64_TLSDESC,                         0x407)
 ELF_RELOC(R_AARCH64_IRELATIVE,                       0x408)

diff --git a/test/tools/llvm-readobj/Inputs/relocs.py b/test/tools/llvm-readobj/Inputs/relocs.py
index 8e621cef5cd98ba37cb51a096f53fe915d3d22a0..d0a7341dcb63398534d0f79f6f5956f2999f0413 100644 (file)
--- a/test/tools/llvm-readobj/Inputs/relocs.py
+++ b/test/tools/llvm-readobj/Inputs/relocs.py
@@ -710,8 +710,8 @@ class Relocs_Elf_AArch64(Enum):
   R_AARCH64_GLOB_DAT                    = 0x401
   R_AARCH64_JUMP_SLOT                   = 0x402
   R_AARCH64_RELATIVE                    = 0x403
-  R_AARCH64_TLS_DTPREL64                = 0x404
-  R_AARCH64_TLS_DTPMOD64                = 0x405
+  R_AARCH64_TLS_DTPMOD64                = 0x404
+  R_AARCH64_TLS_DTPREL64                = 0x405
   R_AARCH64_TLS_TPREL64                 = 0x406
   R_AARCH64_TLSDESC                     = 0x407
   R_AARCH64_IRELATIVE                   = 0x408

diff --git a/test/tools/llvm-readobj/reloc-types-elf-aarch64.test b/test/tools/llvm-readobj/reloc-types-elf-aarch64.test
index ba9cc7da65c7222dcc4d3332499236f71c2c42bf..f50668c353920fbce4f2a28ee855c32b635eeff8 100644 (file)
--- a/test/tools/llvm-readobj/reloc-types-elf-aarch64.test
+++ b/test/tools/llvm-readobj/reloc-types-elf-aarch64.test
@@ -122,8 +122,8 @@
 # CHECK: Type: R_AARCH64_GLOB_DAT (1025)
 # CHECK: Type: R_AARCH64_JUMP_SLOT (1026)
 # CHECK: Type: R_AARCH64_RELATIVE (1027)
-# CHECK: Type: R_AARCH64_TLS_DTPREL64 (1028)
-# CHECK: Type: R_AARCH64_TLS_DTPMOD64 (1029)
+# CHECK: Type: R_AARCH64_TLS_DTPMOD64 (1028)
+# CHECK: Type: R_AARCH64_TLS_DTPREL64 (1029)
 # CHECK: Type: R_AARCH64_TLS_TPREL64 (1030)
 # CHECK: Type: R_AARCH64_TLSDESC (1031)
 # CHECK: Type: R_AARCH64_IRELATIVE (1032)
@@ -382,9 +382,9 @@ Sections:
       - Offset: 0x00000000000001D4
         Type:   R_AARCH64_RELATIVE
       - Offset: 0x00000000000001D8
-        Type:   R_AARCH64_TLS_DTPREL64
-      - Offset: 0x00000000000001DC
         Type:   R_AARCH64_TLS_DTPMOD64
+      - Offset: 0x00000000000001DC
+        Type:   R_AARCH64_TLS_DTPREL64
       - Offset: 0x00000000000001E0
         Type:   R_AARCH64_TLS_TPREL64
       - Offset: 0x00000000000001E4