Make use of common-symbol alignment info in ELF loader.

Patch by Amara Emerson.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166919 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 2 deletions

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
index 45633e735c..3baec3cf2a 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
@@ -140,8 +140,10 @@ protected:
   typedef StringMap<SymbolLoc> SymbolTableMap;
   SymbolTableMap GlobalSymbolTable;
 
-  // Keep a map of common symbols to their sizes
-  typedef std::map<SymbolRef, unsigned> CommonSymbolMap;
+  // Pair representing the size and alignment requirement for a common symbol.
+  typedef std::pair<unsigned, unsigned> CommonSymbolInfo;
+  // Keep a map of common symbols to their info pairs
+  typedef std::map<SymbolRef, CommonSymbolInfo> CommonSymbolMap;
 
   // For each symbol, keep a list of relocations based on it. Anytime
   // its address is reassigned (the JIT re-compiled the function, e.g.),
@@ -192,6 +194,13 @@ protected:
     return (uint8_t*)Sections[SectionID].Address;
   }
 
+  // Subclasses can override this method to get the alignment requirement of
+  // a common symbol. Returns no alignment requirement if not implemented.
+  virtual unsigned getCommonSymbolAlignment(const SymbolRef &Sym) {
+    return 0;
+  }
+
+
   void writeInt16BE(uint8_t *Addr, uint16_t Value) {
     if (sys::isLittleEndianHost())
       Value = sys::SwapByteOrder(Value);