IR: Remove implicit iterator conversions from lib/IR, NFC

Stop converting implicitly between iterators and pointers/references in
lib/IR.  For convenience, I've added a `getIterator()` accessor to
`ilist_node` so that callers don't need to know how to spell the
iterator class (i.e., they can use `X.getIterator()` instead of
`Function::iterator(X)`).

I'll eventually disallow these implicit conversions entirely, but
there's a lot of code, so it doesn't make sense to do it all in one
patch.  One library or so at a time.

Why?  To root out cases of `getNextNode()` and `getPrevNode()` being
used in iterator logic.  The design of `ilist` makes that invalid when
the current node could be at the back of the list, but it happens to
"work" right now because of a bug where those functions never return
`nullptr` if you're using a half-node sentinel.  Before I can fix the
function, I have to remove uses of it that rely on it misbehaving.
(Maybe the function should just be deleted anyway?  But I don't want
deleting it -- potentially a huge project -- to block fixing
ilist/iplist.)

llvm-svn: 249782

1 files changed, 5 insertions, 5 deletions

diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index 11ece2ed1b1..8fde4b8e9d7 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -178,7 +178,7 @@ GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
   }
 
   if (Before)
-    Before->getParent()->getGlobalList().insert(Before, this);
+    Before->getParent()->getGlobalList().insert(Before->getIterator(), this);
   else
     M.getGlobalList().push_back(this);
 }
@@ -188,11 +188,11 @@ void GlobalVariable::setParent(Module *parent) {
 }
 
 void GlobalVariable::removeFromParent() {
-  getParent()->getGlobalList().remove(this);
+  getParent()->getGlobalList().remove(getIterator());
 }
 
 void GlobalVariable::eraseFromParent() {
-  getParent()->getGlobalList().erase(this);
+  getParent()->getGlobalList().erase(getIterator());
 }
 
 void GlobalVariable::setInitializer(Constant *InitVal) {
@@ -276,11 +276,11 @@ void GlobalAlias::setParent(Module *parent) {
 }
 
 void GlobalAlias::removeFromParent() {
-  getParent()->getAliasList().remove(this);
+  getParent()->getAliasList().remove(getIterator());
 }
 
 void GlobalAlias::eraseFromParent() {
-  getParent()->getAliasList().erase(this);
+  getParent()->getAliasList().erase(getIterator());
 }
 
 void GlobalAlias::setAliasee(Constant *Aliasee) {