[RuntimeDyld] Support R_390_PC64 relocation type

[bryanpkc]

Summary

When the MCJIT generates ELF code, some DWARF data requires 64-bit PC-relative relocation (R_390_PC64). This patch adds support for R_390_PC64 relocation to RuntimeDyld::resolveSystemZRelocation, to avoid an assertion failure.

[uweigand]

LGTM, thanks!

As an extra benefit, it would be great if you could also add test cases for the remaining relocation types that are already supported but don't have a test case yet ... (To be clear, this is not a requirement for committing this patch ...)

[bryanpkc]

Thanks for the review. I will try to add some test cases in a future patch.

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

case ELF::R_390_PC32: {
     int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
     assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
     writeInt32BE(LocalAddress, Delta);
     break;
   }
   case ELF::R_390_64:
     writeInt64BE(LocalAddress, Value + Addend);
     break;
+  case ELF::R_390_PC64: {
+    int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
+    writeInt64BE(LocalAddress, Delta);
+    break;
+  }
   }
 }
 
 // The target location for the relocation is described by RE.SectionID and
 // RE.Offset.  RE.SectionID can be used to find the SectionEntry.  Each
 // SectionEntry has three members describing its location.
 // SectionEntry::Address is the address at which the section has been loaded
 // into memory in the current (host) process.  SectionEntry::LoadAddress is the

test/ExecutionEngine/RuntimeDyld/SystemZ/Inputs/rtdyld-globals.ll

+@foo = global i8 0

test/ExecutionEngine/RuntimeDyld/SystemZ/cfi-relo-pc64.s

+// Test that R_390_PC32 and R_390_PC64 relocations can be generated.
+// RUN: llvm-mc -triple s390x-linux-gnu -relocation-model=pic -filetype=obj %s -o - | llvm-readobj -s -sr -sd | FileCheck %s
+
+// Test that RuntimeDyld can fix up such relocations.
+// RUN: llvm-mc -triple s390x-linux-gnu -relocation-model=pic -filetype=obj %s -o %T/test-s390x-cfi-relo-pc64.o
+// RUN: llc -mtriple=s390x-linux-gnu -relocation-model=pic -filetype=obj %S/Inputs/rtdyld-globals.ll -o %T/test-s390x-rtdyld-globals.o
+// RUN: llvm-rtdyld -triple=s390x-linux-gnu -verify %T/test-s390x-cfi-relo-pc64.o %T/test-s390x-rtdyld-globals.o
+
+f1:
+    .cfi_startproc
+    .cfi_personality 0x9c, foo // DW_EH_PE_indirect|DW_EH_PE_pcrel|DW_EH_PE_sdata8 (0x9c)
+    lr %r0, %r0
+    .cfi_endproc
+
+// CHECK:        Section {
+// CHECK:          Index:
+// CHECK:          Name: .rela.eh_frame
+// CHECK-NEXT:     Type: SHT_RELA
+// CHECK-NEXT:     Flags [
+// CHECK-NEXT:     ]
+// CHECK-NEXT:     Address: 0x0
+// CHECK-NEXT:     Offset:
+// CHECK-NEXT:     Size: 48
+// CHECK-NEXT:     Link:
+// CHECK-NEXT:     Info:
+// CHECK-NEXT:     AddressAlignment: 8
+// CHECK-NEXT:     EntrySize: 24
+// CHECK-NEXT:     Relocations [
+// CHECK-NEXT:       0x12 R_390_PC64 foo 0x0
+// CHECK-NEXT:       0x28 R_390_PC32 .text 0x0
+// CHECK-NEXT:     ]
+// CHECK:        }