[llvm] r351992 - [ADT] Notify ilist traits about in-list transfers
Reid Kleckner via llvm-commits
llvm-commits at lists.llvm.org
Wed Jan 23 14:59:53 PST 2019
Author: rnk
Date: Wed Jan 23 14:59:52 2019
New Revision: 351992
URL: http://llvm.org/viewvc/llvm-project?rev=351992&view=rev
Log:
[ADT] Notify ilist traits about in-list transfers
Summary:
Previously no client of ilist traits has needed to know about transfers
of nodes within the same list, so as an optimization, ilist doesn't call
transferNodesFromList in that case. However, now there are clients that
want to use ilist traits to cache instruction ordering information to
optimize dominance queries of instructions in the same basic block.
This change updates the existing ilist traits users to detect in-list
transfers and do nothing in that case.
After this change, we can start caching instruction ordering information
in LLVM IR data structures. There are two main ways to do that:
- by putting an order integer into the Instruction class
- by maintaining order integers in a hash table on BasicBlock
I plan to implement and measure both, but I wanted to commit this change
first to enable other out of tree ilist clients to implement this
optimization as well.
Reviewers: lattner, hfinkel, chandlerc
Subscribers: hiraditya, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D57120
Modified:
llvm/trunk/include/llvm/ADT/ilist.h
llvm/trunk/include/llvm/CodeGen/MachineFunction.h
llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
llvm/trunk/lib/IR/SymbolTableListTraitsImpl.h
llvm/trunk/unittests/ADT/IListTest.cpp
Modified: llvm/trunk/include/llvm/ADT/ilist.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/ilist.h?rev=351992&r1=351991&r2=351992&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/ilist.h (original)
+++ llvm/trunk/include/llvm/ADT/ilist.h Wed Jan 23 14:59:52 2019
@@ -65,9 +65,8 @@ template <typename NodeTy> struct ilist_
void addNodeToList(NodeTy *) {}
void removeNodeFromList(NodeTy *) {}
- /// Callback before transferring nodes to this list.
- ///
- /// \pre \c this!=&OldList
+ /// Callback before transferring nodes to this list. The nodes may already be
+ /// in this same list.
template <class Iterator>
void transferNodesFromList(ilist_callback_traits &OldList, Iterator /*first*/,
Iterator /*last*/) {
@@ -286,8 +285,8 @@ private:
if (position == last)
return;
- if (this != &L2) // Notify traits we moved the nodes...
- this->transferNodesFromList(L2, first, last);
+ // Notify traits we moved the nodes...
+ this->transferNodesFromList(L2, first, last);
base_list_type::splice(position, L2, first, last);
}
Modified: llvm/trunk/include/llvm/CodeGen/MachineFunction.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineFunction.h?rev=351992&r1=351991&r2=351992&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineFunction.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineFunction.h Wed Jan 23 14:59:52 2019
@@ -85,7 +85,7 @@ template <> struct ilist_callback_traits
template <class Iterator>
void transferNodesFromList(ilist_callback_traits &OldList, Iterator, Iterator) {
- llvm_unreachable("Never transfer between lists");
+ assert(this == &OldList && "never transfer MBBs between functions");
}
};
Modified: llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp?rev=351992&r1=351991&r2=351992&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp Wed Jan 23 14:59:52 2019
@@ -132,8 +132,12 @@ void ilist_traits<MachineInstr>::transfe
instr_iterator First,
instr_iterator Last) {
assert(Parent->getParent() == FromList.Parent->getParent() &&
- "MachineInstr parent mismatch!");
- assert(this != &FromList && "Called without a real transfer...");
+ "cannot transfer MachineInstrs between MachineFunctions");
+
+ // If it's within the same BB, there's nothing to do.
+ if (this == &FromList)
+ return;
+
assert(Parent != FromList.Parent && "Two lists have the same parent?");
// If splicing between two blocks within the same function, just update the
Modified: llvm/trunk/lib/IR/SymbolTableListTraitsImpl.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/SymbolTableListTraitsImpl.h?rev=351992&r1=351991&r2=351992&view=diff
==============================================================================
--- llvm/trunk/lib/IR/SymbolTableListTraitsImpl.h (original)
+++ llvm/trunk/lib/IR/SymbolTableListTraitsImpl.h Wed Jan 23 14:59:52 2019
@@ -83,7 +83,8 @@ void SymbolTableListTraits<ValueSubClass
SymbolTableListTraits &L2, iterator first, iterator last) {
// We only have to do work here if transferring instructions between BBs
ItemParentClass *NewIP = getListOwner(), *OldIP = L2.getListOwner();
- assert(NewIP != OldIP && "Expected different list owners");
+ if (NewIP == OldIP)
+ return;
// We only have to update symbol table entries if we are transferring the
// instructions to a different symtab object...
Modified: llvm/trunk/unittests/ADT/IListTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/IListTest.cpp?rev=351992&r1=351991&r2=351992&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/IListTest.cpp (original)
+++ llvm/trunk/unittests/ADT/IListTest.cpp Wed Jan 23 14:59:52 2019
@@ -207,6 +207,12 @@ struct NodeWithCallback : ilist_node<Nod
} // end namespace
namespace llvm {
+// These nodes are stack-allocated for testing purposes, so don't let the ilist
+// own or delete them.
+template <> struct ilist_alloc_traits<NodeWithCallback> {
+ static void deleteNode(NodeWithCallback *) {}
+};
+
template <> struct ilist_callback_traits<NodeWithCallback> {
void addNodeToList(NodeWithCallback *N) { N->IsInList = true; }
void removeNodeFromList(NodeWithCallback *N) { N->IsInList = false; }
@@ -247,6 +253,30 @@ TEST(IListTest, addNodeToList) {
ASSERT_TRUE(N.WasTransferred);
}
+TEST(IListTest, sameListSplice) {
+ NodeWithCallback N1(1);
+ NodeWithCallback N2(2);
+ ASSERT_FALSE(N1.WasTransferred);
+ ASSERT_FALSE(N2.WasTransferred);
+
+ ilist<NodeWithCallback> L1;
+ L1.insert(L1.end(), &N1);
+ L1.insert(L1.end(), &N2);
+ ASSERT_EQ(2u, L1.size());
+ ASSERT_EQ(&N1, &L1.front());
+ ASSERT_FALSE(N1.WasTransferred);
+ ASSERT_FALSE(N2.WasTransferred);
+
+ // Swap the nodes with splice inside the same list. Check that we get the
+ // transfer callback.
+ L1.splice(L1.begin(), L1, std::next(L1.begin()), L1.end());
+ ASSERT_EQ(2u, L1.size());
+ ASSERT_EQ(&N1, &L1.back());
+ ASSERT_EQ(&N2, &L1.front());
+ ASSERT_FALSE(N1.WasTransferred);
+ ASSERT_TRUE(N2.WasTransferred);
+}
+
struct PrivateNode : private ilist_node<PrivateNode> {
friend struct llvm::ilist_detail::NodeAccess;
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