[RuntimeDyld] Don't try to get the contents of sections that don't have any

[oota-llvm.git] / lib / ExecutionEngine / RuntimeDyld / RuntimeDyld.cpp

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 42a0205331b031974d08cba4ceee4bed9f61602d..27cd09834df517951269b3b7275d045d842991eb 100644 (file)
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -82,23 +82,34 @@ static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
 void RuntimeDyldImpl::resolveRelocations() {
   MutexGuard locked(lock);
 
+  // Print out the sections prior to relocation.
+  DEBUG(
+    for (int i = 0, e = Sections.size(); i != e; ++i)
+      dumpSectionMemory(Sections[i], "before relocations");
+  );
+
   // 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) {
+  // Iterate over all outstanding relocations
+  for (auto it = Relocations.begin(), e = Relocations.end(); it != e; ++it) {
     // 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"
+    int Idx = it->getFirst();
+    uint64_t Addr = Sections[Idx].LoadAddress;
+    DEBUG(dbgs() << "Resolving relocations Section #" << Idx << "\t"
                  << format("%p", (uintptr_t)Addr) << "\n");
-    DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
-    resolveRelocationList(Relocations[i], Addr);
-    DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
-    Relocations.erase(i);
+    resolveRelocationList(it->getSecond(), Addr);
   }
+  Relocations.clear();
+
+  // Print out sections after relocation.
+  DEBUG(
+    for (int i = 0, e = Sections.size(); i != e; ++i)
+      dumpSectionMemory(Sections[i], "after relocations");
+  );
+
 }
 
 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
@@ -171,8 +182,6 @@ RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
           continue;
         uint64_t SectOffset;
         Check(getOffset(*I, *SI, SectOffset));
-        StringRef SectionData;
-        Check(SI->getContents(SectionData));
         bool IsCode = SI->isText();
         unsigned SectionID =
             findOrEmitSection(Obj, *SI, IsCode, LocalSections);
@@ -557,12 +566,14 @@ unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
   uint8_t *Addr;
   const char *pData = nullptr;
 
-  // In either case, set the location of the unrelocated section in memory,
-  // since we still process relocations for it even if we're not applying them.
-  Check(Section.getContents(data));
-  // Virtual sections have no data in the object image, so leave pData = 0
-  if (!IsVirtual)
+  // If this section contains any bits (i.e. isn't a virtual or bss section),
+  // grab a reference to them.
+  if (!IsVirtual && !IsZeroInit) {
+    // In either case, set the location of the unrelocated section in memory,
+    // since we still process relocations for it even if we're not applying them.
+    Check(Section.getContents(data));
     pData = data.data();
+  }
 
   // Code section alignment needs to be at least as high as stub alignment or
   // padding calculations may by incorrect when the section is remapped to a