[MCJIT] Fix an iterator invalidation bug in MCJIT::finalizeObject.

The finalizeObject method calls generateCodeForModule on each of the currently
'added' objects, but generateCodeForModule moves objects out of the 'added'
set as it's called. To avoid iterator invalidation issues, the added set is
copied out before any calls to generateCodeForModule.

This should fix http://llvm.org/PR20851 .

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217291 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/ExecutionEngine/MCJIT/MCJIT.cpp b/lib/ExecutionEngine/MCJIT/MCJIT.cpp
index 3dd2057..8ff41ff 100644 (file)
--- a/lib/ExecutionEngine/MCJIT/MCJIT.cpp
+++ b/lib/ExecutionEngine/MCJIT/MCJIT.cpp
@@ -225,12 +225,14 @@ void MCJIT::finalizeLoadedModules() {
 void MCJIT::finalizeObject() {
   MutexGuard locked(lock);
 
-  for (ModulePtrSet::iterator I = OwnedModules.begin_added(),
-                              E = OwnedModules.end_added();
-       I != E; ++I) {
-    Module *M = *I;
+  // Generate code for module is going to move objects out of the 'added' list,
+  // so we need to copy that out before using it:
+  SmallVector<Module*, 16> ModsToAdd;
+  for (auto M : OwnedModules.added())
+    ModsToAdd.push_back(M);
+
+  for (auto M : ModsToAdd)
     generateCodeForModule(M);
-  }
 
   finalizeLoadedModules();
 }

diff --git a/lib/ExecutionEngine/MCJIT/MCJIT.h b/lib/ExecutionEngine/MCJIT/MCJIT.h
index 9a4e53f..624a431 100644 (file)
--- a/lib/ExecutionEngine/MCJIT/MCJIT.h
+++ b/lib/ExecutionEngine/MCJIT/MCJIT.h
@@ -118,6 +118,9 @@ class MCJIT : public ExecutionEngine {
 
     ModulePtrSet::iterator begin_added() { return AddedModules.begin(); }
     ModulePtrSet::iterator end_added() { return AddedModules.end(); }
+    iterator_range<ModulePtrSet::iterator> added() {
+      return iterator_range<ModulePtrSet::iterator>(begin_added(), end_added());
+    }
 
     ModulePtrSet::iterator begin_loaded() { return LoadedModules.begin(); }
     ModulePtrSet::iterator end_loaded() { return LoadedModules.end(); }