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llvm-mirror/lib/IR/SymbolTableListTraitsImpl.h
Reid Kleckner aec41a7a6c [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

llvm-svn: 351992
2019-01-23 22:59:52 +00:00

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3.7 KiB
C++

//===-- llvm/SymbolTableListTraitsImpl.h - Implementation ------*- C++ -*--===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the stickier parts of the SymbolTableListTraits class,
// and is explicitly instantiated where needed to avoid defining all this code
// in a widely used header.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_IR_SYMBOLTABLELISTTRAITSIMPL_H
#define LLVM_LIB_IR_SYMBOLTABLELISTTRAITSIMPL_H
#include "llvm/IR/SymbolTableListTraits.h"
#include "llvm/IR/ValueSymbolTable.h"
namespace llvm {
/// setSymTabObject - This is called when (f.e.) the parent of a basic block
/// changes. This requires us to remove all the instruction symtab entries from
/// the current function and reinsert them into the new function.
template <typename ValueSubClass>
template <typename TPtr>
void SymbolTableListTraits<ValueSubClass>::setSymTabObject(TPtr *Dest,
TPtr Src) {
// Get the old symtab and value list before doing the assignment.
ValueSymbolTable *OldST = getSymTab(getListOwner());
// Do it.
*Dest = Src;
// Get the new SymTab object.
ValueSymbolTable *NewST = getSymTab(getListOwner());
// If there is nothing to do, quick exit.
if (OldST == NewST) return;
// Move all the elements from the old symtab to the new one.
ListTy &ItemList = getList(getListOwner());
if (ItemList.empty()) return;
if (OldST) {
// Remove all entries from the previous symtab.
for (auto I = ItemList.begin(); I != ItemList.end(); ++I)
if (I->hasName())
OldST->removeValueName(I->getValueName());
}
if (NewST) {
// Add all of the items to the new symtab.
for (auto I = ItemList.begin(); I != ItemList.end(); ++I)
if (I->hasName())
NewST->reinsertValue(&*I);
}
}
template <typename ValueSubClass>
void SymbolTableListTraits<ValueSubClass>::addNodeToList(ValueSubClass *V) {
assert(!V->getParent() && "Value already in a container!!");
ItemParentClass *Owner = getListOwner();
V->setParent(Owner);
if (V->hasName())
if (ValueSymbolTable *ST = getSymTab(Owner))
ST->reinsertValue(V);
}
template <typename ValueSubClass>
void SymbolTableListTraits<ValueSubClass>::removeNodeFromList(
ValueSubClass *V) {
V->setParent(nullptr);
if (V->hasName())
if (ValueSymbolTable *ST = getSymTab(getListOwner()))
ST->removeValueName(V->getValueName());
}
template <typename ValueSubClass>
void SymbolTableListTraits<ValueSubClass>::transferNodesFromList(
SymbolTableListTraits &L2, iterator first, iterator last) {
// We only have to do work here if transferring instructions between BBs
ItemParentClass *NewIP = getListOwner(), *OldIP = L2.getListOwner();
if (NewIP == OldIP)
return;
// We only have to update symbol table entries if we are transferring the
// instructions to a different symtab object...
ValueSymbolTable *NewST = getSymTab(NewIP);
ValueSymbolTable *OldST = getSymTab(OldIP);
if (NewST != OldST) {
for (; first != last; ++first) {
ValueSubClass &V = *first;
bool HasName = V.hasName();
if (OldST && HasName)
OldST->removeValueName(V.getValueName());
V.setParent(NewIP);
if (NewST && HasName)
NewST->reinsertValue(&V);
}
} else {
// Just transferring between blocks in the same function, simply update the
// parent fields in the instructions...
for (; first != last; ++first)
first->setParent(NewIP);
}
}
} // End llvm namespace
#endif