llvm-6502/lib/Transforms/IPO/LoopExtractor.cpp
Reid Spencer 9133fe2895 Apply the VISIBILITY_HIDDEN field to the remaining anonymous classes in
the Transforms library. This reduces debug library size by 132 KB, debug
binary size by 376 KB, and reduces link time for llvm tools slightly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33939 91177308-0d34-0410-b5e6-96231b3b80d8
2007-02-05 23:32:05 +00:00

193 lines
6.7 KiB
C++

//===- LoopExtractor.cpp - Extract each loop into a new function ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// A pass wrapper around the ExtractLoop() scalar transformation to extract each
// top-level loop into its own new function. If the loop is the ONLY loop in a
// given function, it is not touched. This is a pass most useful for debugging
// via bugpoint.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "loop-extract"
#include "llvm/Transforms/IPO.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/FunctionUtils.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(NumExtracted, "Number of loops extracted");
namespace {
// FIXME: This is not a function pass, but the PassManager doesn't allow
// Module passes to require FunctionPasses, so we can't get loop info if we're
// not a function pass.
struct VISIBILITY_HIDDEN LoopExtractor : public FunctionPass {
unsigned NumLoops;
LoopExtractor(unsigned numLoops = ~0) : NumLoops(numLoops) {}
virtual bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequiredID(BreakCriticalEdgesID);
AU.addRequiredID(LoopSimplifyID);
AU.addRequired<DominatorSet>();
AU.addRequired<LoopInfo>();
}
};
RegisterPass<LoopExtractor>
X("loop-extract", "Extract loops into new functions");
/// SingleLoopExtractor - For bugpoint.
struct SingleLoopExtractor : public LoopExtractor {
SingleLoopExtractor() : LoopExtractor(1) {}
};
RegisterPass<SingleLoopExtractor>
Y("loop-extract-single", "Extract at most one loop into a new function");
} // End anonymous namespace
// createLoopExtractorPass - This pass extracts all natural loops from the
// program into a function if it can.
//
FunctionPass *llvm::createLoopExtractorPass() { return new LoopExtractor(); }
bool LoopExtractor::runOnFunction(Function &F) {
LoopInfo &LI = getAnalysis<LoopInfo>();
// If this function has no loops, there is nothing to do.
if (LI.begin() == LI.end())
return false;
DominatorSet &DS = getAnalysis<DominatorSet>();
// If there is more than one top-level loop in this function, extract all of
// the loops.
bool Changed = false;
if (LI.end()-LI.begin() > 1) {
for (LoopInfo::iterator i = LI.begin(), e = LI.end(); i != e; ++i) {
if (NumLoops == 0) return Changed;
--NumLoops;
Changed |= ExtractLoop(DS, *i) != 0;
++NumExtracted;
}
} else {
// Otherwise there is exactly one top-level loop. If this function is more
// than a minimal wrapper around the loop, extract the loop.
Loop *TLL = *LI.begin();
bool ShouldExtractLoop = false;
// Extract the loop if the entry block doesn't branch to the loop header.
TerminatorInst *EntryTI = F.getEntryBlock().getTerminator();
if (!isa<BranchInst>(EntryTI) ||
!cast<BranchInst>(EntryTI)->isUnconditional() ||
EntryTI->getSuccessor(0) != TLL->getHeader())
ShouldExtractLoop = true;
else {
// Check to see if any exits from the loop are more than just return
// blocks.
std::vector<BasicBlock*> ExitBlocks;
TLL->getExitBlocks(ExitBlocks);
for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
if (!isa<ReturnInst>(ExitBlocks[i]->getTerminator())) {
ShouldExtractLoop = true;
break;
}
}
if (ShouldExtractLoop) {
if (NumLoops == 0) return Changed;
--NumLoops;
Changed |= ExtractLoop(DS, TLL) != 0;
++NumExtracted;
} else {
// Okay, this function is a minimal container around the specified loop.
// If we extract the loop, we will continue to just keep extracting it
// infinitely... so don't extract it. However, if the loop contains any
// subloops, extract them.
for (Loop::iterator i = TLL->begin(), e = TLL->end(); i != e; ++i) {
if (NumLoops == 0) return Changed;
--NumLoops;
Changed |= ExtractLoop(DS, *i) != 0;
++NumExtracted;
}
}
}
return Changed;
}
// createSingleLoopExtractorPass - This pass extracts one natural loop from the
// program into a function if it can. This is used by bugpoint.
//
FunctionPass *llvm::createSingleLoopExtractorPass() {
return new SingleLoopExtractor();
}
namespace {
/// BlockExtractorPass - This pass is used by bugpoint to extract all blocks
/// from the module into their own functions except for those specified by the
/// BlocksToNotExtract list.
class BlockExtractorPass : public ModulePass {
std::vector<BasicBlock*> BlocksToNotExtract;
public:
BlockExtractorPass(std::vector<BasicBlock*> &B) : BlocksToNotExtract(B) {}
BlockExtractorPass() {}
bool runOnModule(Module &M);
};
RegisterPass<BlockExtractorPass>
XX("extract-blocks", "Extract Basic Blocks From Module (for bugpoint use)");
}
// createBlockExtractorPass - This pass extracts all blocks (except those
// specified in the argument list) from the functions in the module.
//
ModulePass *llvm::createBlockExtractorPass(std::vector<BasicBlock*> &BTNE) {
return new BlockExtractorPass(BTNE);
}
bool BlockExtractorPass::runOnModule(Module &M) {
std::set<BasicBlock*> TranslatedBlocksToNotExtract;
for (unsigned i = 0, e = BlocksToNotExtract.size(); i != e; ++i) {
BasicBlock *BB = BlocksToNotExtract[i];
Function *F = BB->getParent();
// Map the corresponding function in this module.
Function *MF = M.getFunction(F->getName());
assert(MF->getFunctionType() == F->getFunctionType() && "Wrong function?");
// Figure out which index the basic block is in its function.
Function::iterator BBI = MF->begin();
std::advance(BBI, std::distance(F->begin(), Function::iterator(BB)));
TranslatedBlocksToNotExtract.insert(BBI);
}
// Now that we know which blocks to not extract, figure out which ones we WANT
// to extract.
std::vector<BasicBlock*> BlocksToExtract;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
if (!TranslatedBlocksToNotExtract.count(BB))
BlocksToExtract.push_back(BB);
for (unsigned i = 0, e = BlocksToExtract.size(); i != e; ++i)
ExtractBasicBlock(BlocksToExtract[i]);
return !BlocksToExtract.empty();
}