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llvm-6502/lib/Transforms/IPO/PartialInlining.cpp
Chandler Carruth 0b8c9a80f2 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-02 11:36:10 +00:00

184 lines
6.3 KiB
C++

//===- PartialInlining.cpp - Inline parts of functions --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass performs partial inlining, typically by inlining an if statement
// that surrounds the body of the function.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "partialinlining"
#include "llvm/Transforms/IPO.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CFG.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/CodeExtractor.h"
using namespace llvm;
STATISTIC(NumPartialInlined, "Number of functions partially inlined");
namespace {
struct PartialInliner : public ModulePass {
virtual void getAnalysisUsage(AnalysisUsage &AU) const { }
static char ID; // Pass identification, replacement for typeid
PartialInliner() : ModulePass(ID) {
initializePartialInlinerPass(*PassRegistry::getPassRegistry());
}
bool runOnModule(Module& M);
private:
Function* unswitchFunction(Function* F);
};
}
char PartialInliner::ID = 0;
INITIALIZE_PASS(PartialInliner, "partial-inliner",
"Partial Inliner", false, false)
ModulePass* llvm::createPartialInliningPass() { return new PartialInliner(); }
Function* PartialInliner::unswitchFunction(Function* F) {
// First, verify that this function is an unswitching candidate...
BasicBlock* entryBlock = F->begin();
BranchInst *BR = dyn_cast<BranchInst>(entryBlock->getTerminator());
if (!BR || BR->isUnconditional())
return 0;
BasicBlock* returnBlock = 0;
BasicBlock* nonReturnBlock = 0;
unsigned returnCount = 0;
for (succ_iterator SI = succ_begin(entryBlock), SE = succ_end(entryBlock);
SI != SE; ++SI)
if (isa<ReturnInst>((*SI)->getTerminator())) {
returnBlock = *SI;
returnCount++;
} else
nonReturnBlock = *SI;
if (returnCount != 1)
return 0;
// Clone the function, so that we can hack away on it.
ValueToValueMapTy VMap;
Function* duplicateFunction = CloneFunction(F, VMap,
/*ModuleLevelChanges=*/false);
duplicateFunction->setLinkage(GlobalValue::InternalLinkage);
F->getParent()->getFunctionList().push_back(duplicateFunction);
BasicBlock* newEntryBlock = cast<BasicBlock>(VMap[entryBlock]);
BasicBlock* newReturnBlock = cast<BasicBlock>(VMap[returnBlock]);
BasicBlock* newNonReturnBlock = cast<BasicBlock>(VMap[nonReturnBlock]);
// Go ahead and update all uses to the duplicate, so that we can just
// use the inliner functionality when we're done hacking.
F->replaceAllUsesWith(duplicateFunction);
// Special hackery is needed with PHI nodes that have inputs from more than
// one extracted block. For simplicity, just split the PHIs into a two-level
// sequence of PHIs, some of which will go in the extracted region, and some
// of which will go outside.
BasicBlock* preReturn = newReturnBlock;
newReturnBlock = newReturnBlock->splitBasicBlock(
newReturnBlock->getFirstNonPHI());
BasicBlock::iterator I = preReturn->begin();
BasicBlock::iterator Ins = newReturnBlock->begin();
while (I != preReturn->end()) {
PHINode* OldPhi = dyn_cast<PHINode>(I);
if (!OldPhi) break;
PHINode* retPhi = PHINode::Create(OldPhi->getType(), 2, "", Ins);
OldPhi->replaceAllUsesWith(retPhi);
Ins = newReturnBlock->getFirstNonPHI();
retPhi->addIncoming(I, preReturn);
retPhi->addIncoming(OldPhi->getIncomingValueForBlock(newEntryBlock),
newEntryBlock);
OldPhi->removeIncomingValue(newEntryBlock);
++I;
}
newEntryBlock->getTerminator()->replaceUsesOfWith(preReturn, newReturnBlock);
// Gather up the blocks that we're going to extract.
std::vector<BasicBlock*> toExtract;
toExtract.push_back(newNonReturnBlock);
for (Function::iterator FI = duplicateFunction->begin(),
FE = duplicateFunction->end(); FI != FE; ++FI)
if (&*FI != newEntryBlock && &*FI != newReturnBlock &&
&*FI != newNonReturnBlock)
toExtract.push_back(FI);
// The CodeExtractor needs a dominator tree.
DominatorTree DT;
DT.runOnFunction(*duplicateFunction);
// Extract the body of the if.
Function* extractedFunction
= CodeExtractor(toExtract, &DT).extractCodeRegion();
InlineFunctionInfo IFI;
// Inline the top-level if test into all callers.
std::vector<User*> Users(duplicateFunction->use_begin(),
duplicateFunction->use_end());
for (std::vector<User*>::iterator UI = Users.begin(), UE = Users.end();
UI != UE; ++UI)
if (CallInst *CI = dyn_cast<CallInst>(*UI))
InlineFunction(CI, IFI);
else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI))
InlineFunction(II, IFI);
// Ditch the duplicate, since we're done with it, and rewrite all remaining
// users (function pointers, etc.) back to the original function.
duplicateFunction->replaceAllUsesWith(F);
duplicateFunction->eraseFromParent();
++NumPartialInlined;
return extractedFunction;
}
bool PartialInliner::runOnModule(Module& M) {
std::vector<Function*> worklist;
worklist.reserve(M.size());
for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI)
if (!FI->use_empty() && !FI->isDeclaration())
worklist.push_back(&*FI);
bool changed = false;
while (!worklist.empty()) {
Function* currFunc = worklist.back();
worklist.pop_back();
if (currFunc->use_empty()) continue;
bool recursive = false;
for (Function::use_iterator UI = currFunc->use_begin(),
UE = currFunc->use_end(); UI != UE; ++UI)
if (Instruction* I = dyn_cast<Instruction>(*UI))
if (I->getParent()->getParent() == currFunc) {
recursive = true;
break;
}
if (recursive) continue;
if (Function* newFunc = unswitchFunction(currFunc)) {
worklist.push_back(newFunc);
changed = true;
}
}
return changed;
}