1 files changed, 105 insertions, 29 deletions

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 943622f..161135a 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -13,12 +13,14 @@
 
 #define DEBUG_TYPE "dyld"
 #include "llvm/ExecutionEngine/RuntimeDyld.h"
+#include "JITRegistrar.h"
 #include "ObjectImageCommon.h"
 #include "RuntimeDyldELF.h"
 #include "RuntimeDyldImpl.h"
 #include "RuntimeDyldMachO.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MathExtras.h"
+#include "llvm/Support/MutexGuard.h"
 #include "llvm/Object/ELF.h"
 
 using namespace llvm;
@@ -27,30 +29,44 @@ using namespace llvm::object;
 // Empty out-of-line virtual destructor as the key function.
 RuntimeDyldImpl::~RuntimeDyldImpl() {}
 
+// Pin the JITRegistrar's and ObjectImage*'s vtables to this file.
+void JITRegistrar::anchor() {}
+void ObjectImage::anchor() {}
+void ObjectImageCommon::anchor() {}
+
 namespace llvm {
 
-StringRef RuntimeDyldImpl::getEHFrameSection() {
-  return StringRef();
+void RuntimeDyldImpl::registerEHFrames() {
+}
+
+void RuntimeDyldImpl::deregisterEHFrames() {
 }
 
 // Resolve the relocations for all symbols we currently know about.
 void RuntimeDyldImpl::resolveRelocations() {
+  MutexGuard locked(lock);
+
   // First, resolve relocations associated with external symbols.
   resolveExternalSymbols();
 
   // Just iterate over the sections we have and resolve all the relocations
   // in them. Gross overkill, but it gets the job done.
   for (int i = 0, e = Sections.size(); i != e; ++i) {
+    // The Section here (Sections[i]) refers to the section in which the
+    // symbol for the relocation is located.  The SectionID in the relocation
+    // entry provides the section to which the relocation will be applied.
     uint64_t Addr = Sections[i].LoadAddress;
     DEBUG(dbgs() << "Resolving relocations Section #" << i
             << "\t" << format("%p", (uint8_t *)Addr)
             << "\n");
     resolveRelocationList(Relocations[i], Addr);
+    Relocations.erase(i);
   }
 }
 
 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
                                         uint64_t TargetAddress) {
+  MutexGuard locked(lock);
   for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
     if (Sections[i].Address == LocalAddress) {
       reassignSectionAddress(i, TargetAddress);
@@ -67,11 +83,15 @@ ObjectImage *RuntimeDyldImpl::createObjectImage(ObjectBuffer *InputBuffer) {
 }
 
 ObjectImage *RuntimeDyldImpl::loadObject(ObjectBuffer *InputBuffer) {
+  MutexGuard locked(lock);
+
   OwningPtr<ObjectImage> obj(createObjectImage(InputBuffer));
   if (!obj)
     report_fatal_error("Unable to create object image from memory buffer!");
 
+  // Save information about our target
   Arch = (Triple::ArchType)obj->getArch();
+  IsTargetLittleEndian = obj->getObjectFile()->isLittleEndian();
 
   // Symbols found in this object
   StringMap<SymbolLoc> LocalSymbols;
@@ -166,6 +186,9 @@ ObjectImage *RuntimeDyldImpl::loadObject(ObjectBuffer *InputBuffer) {
     }
   }
 
+  // Give the subclasses a chance to tie-up any loose ends.
+  finalizeLoad(LocalSections);
+
   return obj.take();
 }
 
@@ -175,8 +198,8 @@ void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
                                         SymbolTableMap &SymbolTable) {
   // Allocate memory for the section
   unsigned SectionID = Sections.size();
-  uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void*),
-                                              SectionID, false);
+  uint8_t *Addr = MemMgr->allocateDataSection(
+    TotalSize, sizeof(void*), SectionID, StringRef(), false);
   if (!Addr)
     report_fatal_error("Unable to allocate memory for common symbols!");
   uint64_t Offset = 0;
@@ -247,6 +270,7 @@ unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
   bool IsZeroInit;
   bool IsReadOnly;
   uint64_t DataSize;
+  unsigned PaddingSize = 0;
   StringRef Name;
   Check(Section.isRequiredForExecution(IsRequired));
   Check(Section.isVirtual(IsVirtual));
@@ -261,6 +285,12 @@ unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
       StubBufSize += StubAlignment - EndAlignment;
   }
 
+  // The .eh_frame section (at least on Linux) needs an extra four bytes padded
+  // with zeroes added at the end.  For MachO objects, this section has a
+  // slightly different name, so this won't have any effect for MachO objects.
+  if (Name == ".eh_frame")
+    PaddingSize = 4;
+
   unsigned Allocate;
   unsigned SectionID = Sections.size();
   uint8_t *Addr;
@@ -269,10 +299,11 @@ unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
   // Some sections, such as debug info, don't need to be loaded for execution.
   // Leave those where they are.
   if (IsRequired) {
-    Allocate = DataSize + StubBufSize;
+    Allocate = DataSize + PaddingSize + StubBufSize;
     Addr = IsCode
-      ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID)
-      : MemMgr->allocateDataSection(Allocate, Alignment, SectionID, IsReadOnly);
+      ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID, Name)
+      : MemMgr->allocateDataSection(Allocate, Alignment, SectionID, Name,
+                                    IsReadOnly);
     if (!Addr)
       report_fatal_error("Unable to allocate section memory!");
 
@@ -286,6 +317,13 @@ unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
     else
       memcpy(Addr, pData, DataSize);
 
+    // Fill in any extra bytes we allocated for padding
+    if (PaddingSize != 0) {
+      memset(Addr + DataSize, 0, PaddingSize);
+      // Update the DataSize variable so that the stub offset is set correctly.
+      DataSize += PaddingSize;
+    }
+
     DEBUG(dbgs() << "emitSection SectionID: " << SectionID
                  << " Name: " << Name
                  << " obj addr: " << format("%p", pData)
@@ -421,6 +459,10 @@ uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr) {
     writeInt16BE(Addr+6,  0x07F1);     // brc 15,%r1
     // 8-byte address stored at Addr + 8
     return Addr;
+  } else if (Arch == Triple::x86_64) {
+    *Addr      = 0xFF; // jmp
+    *(Addr+1)  = 0x25; // rip
+    // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
   }
   return Addr;
 }
@@ -454,30 +496,52 @@ void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
 }
 
 void RuntimeDyldImpl::resolveExternalSymbols() {
-  StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin(),
-                                      e = ExternalSymbolRelocations.end();
-  for (; i != e; i++) {
+  while(!ExternalSymbolRelocations.empty()) {
+    StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
+
     StringRef Name = i->first();
-    RelocationList &Relocs = i->second;
-    SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
-    if (Loc == GlobalSymbolTable.end()) {
-      if (Name.size() == 0) {
-        // This is an absolute symbol, use an address of zero.
-        DEBUG(dbgs() << "Resolving absolute relocations." << "\n");
-        resolveRelocationList(Relocs, 0);
+    if (Name.size() == 0) {
+      // This is an absolute symbol, use an address of zero.
+      DEBUG(dbgs() << "Resolving absolute relocations." << "\n");
+      RelocationList &Relocs = i->second;
+      resolveRelocationList(Relocs, 0);
+    } else {
+      uint64_t Addr = 0;
+      SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
+      if (Loc == GlobalSymbolTable.end()) {
+          // This is an external symbol, try to get its address from
+          // MemoryManager.
+          Addr = MemMgr->getSymbolAddress(Name.data());
+          // The call to getSymbolAddress may have caused additional modules to
+          // be loaded, which may have added new entries to the
+          // ExternalSymbolRelocations map.  Consquently, we need to update our
+          // iterator.  This is also why retrieval of the relocation list
+          // associated with this symbol is deferred until below this point.
+          // New entries may have been added to the relocation list.
+          i = ExternalSymbolRelocations.find(Name);
       } else {
-        // This is an external symbol, try to get its address from
-        // MemoryManager.
-        uint8_t *Addr = (uint8_t*) MemMgr->getPointerToNamedFunction(Name.data(),
-                                                                   true);
-        DEBUG(dbgs() << "Resolving relocations Name: " << Name
-                << "\t" << format("%p", Addr)
-                << "\n");
-        resolveRelocationList(Relocs, (uintptr_t)Addr);
+        // We found the symbol in our global table.  It was probably in a
+        // Module that we loaded previously.
+        SymbolLoc SymLoc = Loc->second;
+        Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
       }
-    } else {
-      report_fatal_error("Expected external symbol");
+
+      // FIXME: Implement error handling that doesn't kill the host program!
+      if (!Addr)
+        report_fatal_error("Program used external function '" + Name +
+                          "' which could not be resolved!");
+
+      updateGOTEntries(Name, Addr);
+      DEBUG(dbgs() << "Resolving relocations Name: " << Name
+              << "\t" << format("0x%lx", Addr)
+              << "\n");
+      // This list may have been updated when we called getSymbolAddress, so
+      // don't change this code to get the list earlier.
+      RelocationList &Relocs = i->second;
+      resolveRelocationList(Relocs, Addr);
     }
+
+    ExternalSymbolRelocations.erase(i);
   }
 }
 
@@ -526,8 +590,10 @@ ObjectImage *RuntimeDyld::loadObject(ObjectBuffer *InputBuffer) {
     case sys::fs::file_magic::bitcode:
     case sys::fs::file_magic::archive:
     case sys::fs::file_magic::coff_object:
+    case sys::fs::file_magic::coff_import_library:
     case sys::fs::file_magic::pecoff_executable:
     case sys::fs::file_magic::macho_universal_binary:
+    case sys::fs::file_magic::windows_resource:
       report_fatal_error("Incompatible object format!");
     }
   } else {
@@ -539,10 +605,14 @@ ObjectImage *RuntimeDyld::loadObject(ObjectBuffer *InputBuffer) {
 }
 
 void *RuntimeDyld::getSymbolAddress(StringRef Name) {
+  if (!Dyld)
+    return NULL;
   return Dyld->getSymbolAddress(Name);
 }
 
 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) {
+  if (!Dyld)
+    return 0;
   return Dyld->getSymbolLoadAddress(Name);
 }
 
@@ -564,8 +634,14 @@ StringRef RuntimeDyld::getErrorString() {
   return Dyld->getErrorString();
 }
 
-StringRef RuntimeDyld::getEHFrameSection() {
-  return Dyld->getEHFrameSection();
+void RuntimeDyld::registerEHFrames() {
+  if (Dyld)
+    Dyld->registerEHFrames();
+}
+
+void RuntimeDyld::deregisterEHFrames() {
+  if (Dyld)
+    Dyld->deregisterEHFrames();
 }
 
 } // end namespace llvm