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
diff --git a/lib/ExecutionEngine/MCJIT/MCJIT.cpp b/lib/ExecutionEngine/MCJIT/MCJIT.cpp
index a0ad985..71d7134 100644
--- a/lib/ExecutionEngine/MCJIT/MCJIT.cpp
+++ b/lib/ExecutionEngine/MCJIT/MCJIT.cpp
@@ -111,6 +111,21 @@
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 b9ff06e..6cffcc5 100644
--- a/lib/ExecutionEngine/MCJIT/MCJIT.h
+++ b/lib/ExecutionEngine/MCJIT/MCJIT.h
@@ -42,6 +42,8 @@
/// @name ExecutionEngine interface implementation
/// @{
+ virtual void finalizeObject();
+
virtual void *getPointerToBasicBlock(BasicBlock *BB);
virtual void *getPointerToFunction(Function *F);
diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index 950b420..f6dccb1 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -36,7 +36,11 @@
// 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) {
- reassignSectionAddress(i, Sections[i].LoadAddress);
+ uint64_t Addr = Sections[i].LoadAddress;
+ DEBUG(dbgs() << "Resolving relocations Section #" << i
+ << "\t" << format("%p", (uint8_t *)Addr)
+ << "\n");
+ resolveRelocationList(Relocations[i], Addr);
}
}
@@ -387,17 +391,15 @@
uint64_t Addr) {
// The address to use for relocation resolution is not
// the address of the local section buffer. We must be doing
- // a remote execution environment of some sort. Re-apply any
- // relocations referencing this section with the given address.
+ // a remote execution environment of some sort. Relocations can't
+ // be applied until all the sections have been moved. The client must
+ // trigger this with a call to MCJIT::finalize() or
+ // RuntimeDyld::resolveRelocations().
//
// Addr is a uint64_t because we can't assume the pointer width
// of the target is the same as that of the host. Just use a generic
// "big enough" type.
Sections[SectionID].LoadAddress = Addr;
- DEBUG(dbgs() << "Resolving relocations Section #" << SectionID
- << "\t" << format("%p", (uint8_t *)Addr)
- << "\n");
- resolveRelocationList(Relocations[SectionID], Addr);
}
void RuntimeDyldImpl::resolveRelocationEntry(const RelocationEntry &RE,