RuntimeDyldELF/AArch64: Implement basic GOT support

This patch implements two GOT relocations:
R_AARCH64_ADR_GOT_PAGE and R_AARCH64_LD64_GOT_LO12_NC

Differential revision: https://reviews.llvm.org/D28571

llvm-svn: 294191

1 files changed, 15 insertions, 6 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
index d1867d091fe..498979705b7 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.h
@@ -43,6 +43,9 @@ class RuntimeDyldELF : public RuntimeDyldImpl {
   bool resolveAArch64ShortBranch(unsigned SectionID, relocation_iterator RelI,
                                  const RelocationValueRef &Value);
 
+  void resolveAArch64Branch(unsigned SectionID, const RelocationValueRef &Value,
+                            relocation_iterator RelI, StubMap &Stubs);
+
   void resolveARMRelocation(const SectionEntry &Section, uint64_t Offset,
                             uint32_t Value, uint32_t Type, int32_t Addend);
 
@@ -88,24 +91,26 @@ class RuntimeDyldELF : public RuntimeDyldImpl {
                             ObjSectionToIDMap &LocalSections,
                             RelocationValueRef &Rel);
 protected:
-  size_t getGOTEntrySize();
+  size_t getGOTEntrySize() override;
 
 private:
   SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
 
   // Allocate no GOT entries for use in the given section.
-  uint64_t allocateGOTEntries(unsigned SectionID, unsigned no);
+  uint64_t allocateGOTEntries(unsigned no);
+
+  // Find GOT entry corresponding to relocation or create new one.
+  uint64_t findOrAllocGOTEntry(const RelocationValueRef &Value,
+                               unsigned GOTRelType);
 
   // Resolve the relvative address of GOTOffset in Section ID and place
   // it at the given Offset
   void resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset,
-                                  uint64_t GOTOffset);
+                                  uint64_t GOTOffset, uint32_t Type);
 
   // For a GOT entry referenced from SectionID, compute a relocation entry
   // that will place the final resolved value in the GOT slot
-  RelocationEntry computeGOTOffsetRE(unsigned SectionID,
-                                     uint64_t GOTOffset,
-                                     uint64_t SymbolOffset,
+  RelocationEntry computeGOTOffsetRE(uint64_t GOTOffset, uint64_t SymbolOffset,
                                      unsigned Type);
 
   // Compute the address in memory where we can find the placeholder
@@ -146,6 +151,10 @@ private:
   SmallVector<SID, 2> UnregisteredEHFrameSections;
   SmallVector<SID, 2> RegisteredEHFrameSections;
 
+  // Map between GOT relocation value and corresponding GOT offset
+  std::map<RelocationValueRef, uint64_t> GOTOffsetMap;
+
+  bool relocationNeedsGot(const RelocationRef &R) const override;
   bool relocationNeedsStub(const RelocationRef &R) const override;
 
 public: