Add a method to indicate section address re-assignment is finished.

Prior to this patch RuntimeDyld attempted to re-apply relocations every time reassignSectionAddress was called (via MCJIT::mapSectionAddress).  In addition to being inefficient and redundant, this led to a problem when a section was temporarily moved too far away from another section with a relative relocation referencing the section being moved.  To fix this, I'm adding a new method (finalizeObject) which the client can call to indicate that it is finished rearranging section addresses so the relocations can safely be applied.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167400 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 17 insertions, 0 deletions

diff --git a/lib/ExecutionEngine/MCJIT/MCJIT.cpp b/lib/ExecutionEngine/MCJIT/MCJIT.cpp
index a0ad985145..71d713468b 100644
--- a/lib/ExecutionEngine/MCJIT/MCJIT.cpp
+++ b/lib/ExecutionEngine/MCJIT/MCJIT.cpp
@@ -111,6 +111,21 @@ void MCJIT::emitObject(Module *m) {
   isCompiled = true;
 }
 
+// FIXME: Add a parameter to identify which object is being finalized when
+// MCJIT supports multiple modules.
+void MCJIT::finalizeObject() {
+  // If the module hasn't been compiled, just do that.
+  if (!isCompiled) {
+    // If the call to Dyld.resolveRelocations() is removed from emitObject()
+    // we'll need to do that here.
+    emitObject(M);
+    return;
+  }
+
+  // Resolve any relocations.
+  Dyld.resolveRelocations();
+}
+
 void *MCJIT::getPointerToBasicBlock(BasicBlock *BB) {
   report_fatal_error("not yet implemented");
 }
diff --git a/lib/ExecutionEngine/MCJIT/MCJIT.h b/lib/ExecutionEngine/MCJIT/MCJIT.h
index b9ff06e701..6cffcc5b82 100644
--- a/lib/ExecutionEngine/MCJIT/MCJIT.h
+++ b/lib/ExecutionEngine/MCJIT/MCJIT.h
@@ -42,6 +42,8 @@ public:
   /// @name ExecutionEngine interface implementation
   /// @{
 
+  virtual void finalizeObject();
+
   virtual void *getPointerToBasicBlock(BasicBlock *BB);
 
   virtual void *getPointerToFunction(Function *F);