Finalize content of synthetic sections prior to Thunk Creation
This change moves the calls to finalizeContent() for each synthetic section
before createThunks(). This will allow us to assign addresses prior to
calling createThunks(). As addition of thunks may add to the static
symbol table and may affect the size of the mips got section we introduce a
couple of additional member functions to update these values.
Differential revision: https://reviews.llvm.org/D29983
llvm-svn: 297277
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 1b9039d..b29805d 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -1022,10 +1022,11 @@
}
template <class ELFT>
-static void finalizeSynthetic(const std::vector<SyntheticSection *> &Sections) {
+static void applySynthetic(const std::vector<SyntheticSection *> &Sections,
+ std::function<void(SyntheticSection *)> Fn) {
for (SyntheticSection *SS : Sections)
if (SS && SS->OutSec && !SS->empty()) {
- SS->finalizeContents();
+ Fn(SS);
SS->OutSec->template assignOffsets<ELFT>();
}
}
@@ -1082,9 +1083,10 @@
addRelIpltSymbols();
// This responsible for splitting up .eh_frame section into
- // pieces. The relocation scan uses those peaces, so this has to be
+ // pieces. The relocation scan uses those pieces, so this has to be
// earlier.
- finalizeSynthetic<ELFT>({In<ELFT>::EhFrame});
+ applySynthetic<ELFT>({In<ELFT>::EhFrame},
+ [](SyntheticSection *SS) { SS->finalizeContents(); });
// Scan relocations. This must be done after every symbol is declared so that
// we can correctly decide if a dynamic relocation is needed.
@@ -1145,21 +1147,9 @@
fixHeaders();
}
- // Some architectures use small displacements for jump instructions.
- // It is linker's responsibility to create thunks containing long
- // jump instructions if jump targets are too far. Create thunks.
- if (Target->NeedsThunks)
- createThunks<ELFT>(OutputSections);
-
- // Fill other section headers. The dynamic table is finalized
- // at the end because some tags like RELSZ depend on result
- // of finalizing other sections.
- for (OutputSection *Sec : OutputSections)
- Sec->finalize<ELFT>();
-
// Dynamic section must be the last one in this list and dynamic
// symbol table section (DynSymTab) must be the first one.
- finalizeSynthetic<ELFT>(
+ applySynthetic<ELFT>(
{In<ELFT>::DynSymTab, In<ELFT>::Bss, In<ELFT>::BssRelRo,
In<ELFT>::GnuHashTab, In<ELFT>::HashTab, In<ELFT>::SymTab,
In<ELFT>::ShStrTab, In<ELFT>::StrTab, In<ELFT>::VerDef,
@@ -1168,7 +1158,32 @@
In<ELFT>::RelaDyn, In<ELFT>::RelaIplt, In<ELFT>::RelaPlt,
In<ELFT>::Plt, In<ELFT>::Iplt, In<ELFT>::Plt,
In<ELFT>::EhFrameHdr, In<ELFT>::VerSym, In<ELFT>::VerNeed,
- In<ELFT>::Dynamic});
+ In<ELFT>::Dynamic},
+ [](SyntheticSection *SS) { SS->finalizeContents(); });
+
+ // Some architectures use small displacements for jump instructions.
+ // It is linker's responsibility to create thunks containing long
+ // jump instructions if jump targets are too far. Create thunks.
+ if (Target->NeedsThunks) {
+ // FIXME: only ARM Interworking and Mips LA25 Thunks are implemented,
+ // these
+ // do not require address information. To support range extension Thunks
+ // we need to assign addresses so that we can tell if jump instructions
+ // are out of range. This will need to turn into a loop that converges
+ // when no more Thunks are added
+ if (createThunks<ELFT>(OutputSections))
+ applySynthetic<ELFT>({In<ELFT>::MipsGot},
+ [](SyntheticSection *SS) { SS->updateAllocSize(); });
+ }
+ // Fill other section headers. The dynamic table is finalized
+ // at the end because some tags like RELSZ depend on result
+ // of finalizing other sections.
+ for (OutputSection *Sec : OutputSections)
+ Sec->finalize<ELFT>();
+
+ // createThunks may have added local symbols to the static symbol table
+ applySynthetic<ELFT>({In<ELFT>::SymTab, In<ELFT>::ShStrTab, In<ELFT>::StrTab},
+ [](SyntheticSection *SS) { SS->postThunkContents(); });
}
template <class ELFT> void Writer<ELFT>::addPredefinedSections() {