This patch improves the MCJIT runtime dynamic loader by adding new handling

of zero-initialized sections, virtual sections and common symbols
and preventing the loading of sections which are not required for
execution such as debug information.

Patch by Andy Kaylor!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154610 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
index d6430a91c2..bf678af6ec 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
@@ -110,6 +110,9 @@ protected:
   StringMap<SymbolLoc> SymbolTable;
   typedef DenseMap<const char*, SymbolLoc> LocalSymbolMap;
 
+  // Keep a map of common symbols to their sizes
+  typedef std::map<SymbolRef, unsigned> 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.),
   // the relocations get re-resolved.
@@ -149,6 +152,12 @@ protected:
     return (uint8_t*)Sections[SectionID].Address;
   }
 
+  /// \brief Emits a section containing common symbols.
+  /// \return SectionID.
+  unsigned emitCommonSymbols(const CommonSymbolMap &Map,
+                             uint64_t TotalSize,
+                             LocalSymbolMap &Symbols);
+
   /// \brief Emits section data from the object file to the MemoryManager.
   /// \param IsCode if it's true then allocateCodeSection() will be
   ///        used for emmits, else allocateDataSection() will be used.