[JITLink][ELF] Add support for ELF::R_X86_64_REX_GOTPCRELX relocation.

No support for relaxation yet -- this will always use the GOT entry.
llvm · Oct 23, 2020 · e2fceec · e2fceec
1 parent 6e574ab
commit e2fceec
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Showing 2 changed files with 17 additions and 3 deletions.
diff --git a/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp b/llvm/lib/ExecutionEngine/JITLink/ELF_x86_64.cpp
@@ -232,6 +232,7 @@ class ELFLinkGraphBuilder_x86_64 {
     case ELF::R_X86_64_64:
       return ELF_x86_64_Edges::ELFX86RelocationKind::Pointer64;
     case ELF::R_X86_64_GOTPCREL:
+    case ELF::R_X86_64_REX_GOTPCRELX:
       return ELF_x86_64_Edges::ELFX86RelocationKind::PCRel32GOTLoad;
     }
     return make_error<JITLinkError>("Unsupported x86-64 relocation:" +

diff --git a/llvm/test/ExecutionEngine/JITLink/X86/ELF_x86-64_relocations.s b/llvm/test/ExecutionEngine/JITLink/X86/ELF_x86-64_relocations.s
@@ -39,12 +39,25 @@ test_gotpcrel:
 .Lend_test_gotpcrel:
         .size   test_gotpcrel, .Lend_test_gotpcrel-test_gotpcrel
 
+# Test REX_GOTPCRELX handling. We want to check both the offset to the GOT entry and its
+# contents.
+# jitlink-check: decode_operand(test_rex_gotpcrelx, 4) = \
+# jitlink-check:   got_addr(elf_reloc.o, named_data) - next_pc(test_rex_gotpcrelx)
+
+        .globl test_rex_gotpcrelx
+        .p2align      4, 0x90
+        .type   test_rex_gotpcrelx,@function
+test_rex_gotpcrelx:
+	movq    named_data@GOTPCREL(%rip), %rax
+.Lend_test_rex_gotpcrelx:
+        .size   test_rex_gotpcrelx, .Lend_test_gotpcrel-test_rex_gotpcrelx
+
         .type   named_data,@object
         .data
-        .p2align        2
+        .p2align        3
 named_data:
-        .long   42
-        .size   named_data, 4
+        .quad   42
+        .size   named_data, 8
 
 # Test BSS / zero-fill section handling.
 # llvm-jitlink: *{4}bss_variable = 0