[ELF2] getLocalRelTarget should handle R_PPC64_TOC directly

R_PPC64_TOC does not have an associated symbol, but does have a non-zero VA
that target-specific code must compute using some non-trivial rule. We
handled this as a special case in PPC64TargetInfo::relocateOne, where
we knew to write this special address, but that did not work when creating shared
libraries. The special TOC address needs to be the subject of a
R_PPC64_RELATIVE relocation, and so we also need to know how to encode this
special address in the addend of that relocation.

Thus, some target-specific logic is necessary when creating R_PPC64_RELATIVE as
well. To solve this problem, we teach getLocalRelTarget to handle R_PPC64_TOC
as a special case. This allows us to remove the special case in
PPC64TargetInfo::relocateOne (simplifying code there), and naturally allows the
existing logic to do the right thing when creating associated R_PPC64_RELATIVE
relocations for shared libraries.

llvm-svn: 250555

1 files changed, 2 insertions, 6 deletions

diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
index 4ecc80b592c..f45b6c54c2c 100644
--- a/lld/ELF/Target.cpp
+++ b/lld/ELF/Target.cpp
@@ -345,7 +345,7 @@ PPC64TargetInfo::PPC64TargetInfo() {
   VAStart = 0x10000000;
 }
 
-static uint64_t getPPC64TocBase() {
+uint64_t getPPC64TocBase() {
   // The TOC consists of sections .got, .toc, .tocbss, .plt in that
   // order. The TOC starts where the first of these sections starts.
 
@@ -426,11 +426,6 @@ void PPC64TargetInfo::relocateOne(uint8_t *Buf, uint8_t *BufEnd,
   uint64_t P = BaseAddr + Rel.r_offset;
   uint64_t TB = getPPC64TocBase();
 
-  if (Type == R_PPC64_TOC) {
-    write64be(L, TB);
-    return;
-  }
-
   // For a TOC-relative relocation, adjust the addend and proceed in terms of
   // the corresponding ADDR16 relocation type.
   switch (Type) {
@@ -536,6 +531,7 @@ void PPC64TargetInfo::relocateOne(uint8_t *Buf, uint8_t *BufEnd,
     write64be(L, SA - P);
     break;
   case R_PPC64_ADDR64:
+  case R_PPC64_TOC:
     write64be(L, SA);
     break;
   default: