commit a32d71be4c676b541c115bf1a960e56ea43d5231
author Lang Hames <lhames@gmail.com> Sun Oct 18 01:41:37 2015 +0000
committer Lang Hames <lhames@gmail.com> Sun Oct 18 01:41:37 2015 +0000
tree eb48c50a6e3c02ea3cf007048aa288d6ead6af8e
parent dab183ed40249328531acd424b5c512f86eca77d

[RuntimeDyld] Add support for absolute symbols.

llvm-svn: 250639

llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 27cd098..1c276a87 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -162,38 +162,55 @@
        ++I) {
     uint32_t Flags = I->getFlags();
 
-    bool IsCommon = Flags & SymbolRef::SF_Common;
-    if (IsCommon)
+    if (Flags & SymbolRef::SF_Common)
       CommonSymbols.push_back(*I);
     else {
       object::SymbolRef::Type SymType = I->getType();
 
-      if (SymType == object::SymbolRef::ST_Function ||
-          SymType == object::SymbolRef::ST_Data ||
-          SymType == object::SymbolRef::ST_Unknown) {
+      // Get symbol name.
+      ErrorOr<StringRef> NameOrErr = I->getName();
+      Check(NameOrErr.getError());
+      StringRef Name = *NameOrErr;
+  
+      // Compute JIT symbol flags.
+      JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
+      if (Flags & SymbolRef::SF_Weak)
+        RTDyldSymFlags |= JITSymbolFlags::Weak;
+      if (Flags & SymbolRef::SF_Exported)
+        RTDyldSymFlags |= JITSymbolFlags::Exported;
 
-        ErrorOr<StringRef> NameOrErr = I->getName();
-        Check(NameOrErr.getError());
-        StringRef Name = *NameOrErr;
+      if (Flags & SymbolRef::SF_Absolute) {
+        auto Addr = I->getAddress();
+        Check(Addr.getError());
+        uint64_t SectOffset = *Addr;
+        unsigned SectionID = AbsoluteSymbolSection;
+
+        DEBUG(dbgs() << "\tType: " << SymType << " (absolute) Name: " << Name
+                     << " SID: " << SectionID << " Offset: "
+                     << format("%p", (uintptr_t)SectOffset)
+                     << " flags: " << Flags << "\n");
+        GlobalSymbolTable[Name] =
+          SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
+      } else if (SymType == object::SymbolRef::ST_Function ||
+                 SymType == object::SymbolRef::ST_Data ||
+                 SymType == object::SymbolRef::ST_Unknown ||
+                 SymType == object::SymbolRef::ST_Other) {
+
         ErrorOr<section_iterator> SIOrErr = I->getSection();
         Check(SIOrErr.getError());
         section_iterator SI = *SIOrErr;
         if (SI == Obj.section_end())
           continue;
+        // Get symbol offset.
         uint64_t SectOffset;
         Check(getOffset(*I, *SI, SectOffset));
         bool IsCode = SI->isText();
-        unsigned SectionID =
-            findOrEmitSection(Obj, *SI, IsCode, LocalSections);
+        unsigned SectionID = findOrEmitSection(Obj, *SI, IsCode, LocalSections);
+
         DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
                      << " SID: " << SectionID << " Offset: "
                      << format("%p", (uintptr_t)SectOffset)
                      << " flags: " << Flags << "\n");
-        JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
-        if (Flags & SymbolRef::SF_Weak)
-          RTDyldSymFlags |= JITSymbolFlags::Weak;
-        if (Flags & SymbolRef::SF_Exported)
-          RTDyldSymFlags |= JITSymbolFlags::Exported;
         GlobalSymbolTable[Name] =
           SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
       }

llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
index ae199b7..18a555a 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp
@@ -727,7 +727,7 @@
 }
 
 bool RuntimeDyldCheckerImpl::isSymbolValid(StringRef Symbol) const {
-  if (getRTDyld().getSymbolLocalAddress(Symbol))
+  if (getRTDyld().getSymbol(Symbol))
     return true;
   return !!getRTDyld().Resolver.findSymbol(Symbol);
 }

llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
index 518df12..c0a1617 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h
@@ -188,6 +188,8 @@
   friend class RuntimeDyld::LoadedObjectInfo;
   friend class RuntimeDyldCheckerImpl;
 protected:
+  static const unsigned AbsoluteSymbolSection = ~0U;
+
   // The MemoryManager to load objects into.
   RuntimeDyld::MemoryManager &MemMgr;
 
@@ -407,6 +409,9 @@
     if (pos == GlobalSymbolTable.end())
       return nullptr;
     const auto &SymInfo = pos->second;
+    // Absolute symbols do not have a local address.
+    if (SymInfo.getSectionID() == AbsoluteSymbolSection)
+      return nullptr;
     return getSectionAddress(SymInfo.getSectionID()) + SymInfo.getOffset();
   }
 
@@ -417,8 +422,10 @@
     if (pos == GlobalSymbolTable.end())
       return nullptr;
     const auto &SymEntry = pos->second;
-    uint64_t TargetAddr =
-      getSectionLoadAddress(SymEntry.getSectionID()) + SymEntry.getOffset();
+    uint64_t SectionAddr = 0;
+    if (SymEntry.getSectionID() != AbsoluteSymbolSection)
+      SectionAddr = getSectionLoadAddress(SymEntry.getSectionID());
+    uint64_t TargetAddr = SectionAddr + SymEntry.getOffset();
     return RuntimeDyld::SymbolInfo(TargetAddr, SymEntry.getFlags());
   }