[ELF][PPC32] Support .got2 in an output section description

I added `PPC32Got2Section` D62464 to support .got2 but did not implement .got2
in another output section.

PR52799 has a linker script placing .got2 in .rodata, which causes a null
pointer dereference because a MergeSyntheticSection's file is nullptr.
Add the support.

1 files changed, 3 insertions, 5 deletions

diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index 9bf6118..872dd0e 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -3620,14 +3620,12 @@ void PPC32Got2Section::finalizeContents() {
   // .got2 . This function computes outSecOff of each .got2 to be used in
   // PPC32PltCallStub::writeTo(). The purpose of this empty synthetic section is
   // to collect input sections named ".got2".
-  uint32_t offset = 0;
   for (SectionCommand *cmd : getParent()->commands)
     if (auto *isd = dyn_cast<InputSectionDescription>(cmd)) {
       for (InputSection *isec : isd->sections) {
-        if (isec == this)
-          continue;
-        isec->file->ppc32Got2OutSecOff = offset;
-        offset += (uint32_t)isec->getSize();
+        // isec->file may be nullptr for MergeSyntheticSection.
+        if (isec != this && isec->file)
+          isec->file->ppc32Got2 = isec;
       }
     }
 }