llvm-6502/lib/Transforms/IPO/Inliner.cpp
Chris Lattner 775cbdd51a Remove the "really gross hacks" that are there to deal with recursive functions.
Now we collect all of the call sites we are interested in inlining, then inline
them.  This entirely avoids issues with trying to inline a call site we got by
inlining another call site.  This also eliminates iterator invalidation issues.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12770 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-08 06:34:31 +00:00

125 lines
4.8 KiB
C++

//===- InlineCommon.cpp - Code common to all inliners ---------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
//
// This file implements the code shared between the LLVM inliners. This
// implements all of the boring mechanics of the bottom-up inlining.
//
//===----------------------------------------------------------------------===//
#include "Inliner.h"
#include "llvm/Constants.h" // ConstantPointerRef should die
#include "llvm/Module.h"
#include "llvm/iOther.h"
#include "llvm/iTerminators.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "Support/CommandLine.h"
#include "Support/Debug.h"
#include "Support/Statistic.h"
using namespace llvm;
namespace {
Statistic<> NumInlined("inline", "Number of functions inlined");
Statistic<> NumDeleted("inline", "Number of functions deleted because all callers found");
cl::opt<unsigned> // FIXME: 200 is VERY conservative
InlineLimit("inline-threshold", cl::Hidden, cl::init(200),
cl::desc("Control the amount of inlining to perform (default = 200)"));
}
Inliner::Inliner() : InlineThreshold(InlineLimit) {}
int Inliner::getRecursiveInlineCost(CallSite CS) {
return getInlineCost(CS);
}
bool Inliner::runOnSCC(const std::vector<CallGraphNode*> &SCC) {
CallGraph &CG = getAnalysis<CallGraph>();
std::set<Function*> SCCFunctions;
DEBUG(std::cerr << "Inliner visiting SCC:");
for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
SCCFunctions.insert(SCC[i]->getFunction());
DEBUG(std::cerr << " " << (SCC[i]->getFunction() ?
SCC[i]->getFunction()->getName() : "INDIRECTNODE"));
}
DEBUG(std::cerr << "\n");
bool Changed = false;
for (std::set<Function*>::iterator SCCI = SCCFunctions.begin(),
E = SCCFunctions.end(); SCCI != E; ++SCCI) {
Function *F = *SCCI;
if (F == 0 || F->isExternal()) continue;
DEBUG(std::cerr << " Inspecting function: " << F->getName() << "\n");
// Scan through and identify all call sites ahead of time so that we only
// inline call sites in the original functions, not call sites that result
// in inlining other functions.
std::vector<CallSite> CallSites;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
CallSite CS = CallSite::get(I);
if (CS.getInstruction() && CS.getCalledFunction() &&
!CS.getCalledFunction()->isExternal())
CallSites.push_back(CS);
}
// Now that we have all of the call sites, loop over them and inline them if
// it looks profitable to do so.
for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
CallSite CS = CallSites[i];
Function *Callee = CS.getCalledFunction();
// Determine whether this is a function IN the SCC...
bool inSCC = SCCFunctions.count(Callee);
// If the policy determines that we should inline this function,
// try to do so...
int InlineCost = inSCC ? getRecursiveInlineCost(CS) : getInlineCost(CS);
if (InlineCost >= (int)InlineThreshold) {
DEBUG(std::cerr << " NOT Inlining: cost=" << InlineCost
<< ", Call: " << *CS.getInstruction());
} else {
DEBUG(std::cerr << " Inlining: cost=" << InlineCost
<< ", Call: " << *CS.getInstruction());
Function *Caller = CS.getInstruction()->getParent()->getParent();
// Attempt to inline the function...
if (InlineFunction(CS)) {
++NumInlined;
if (Callee->hasOneUse())
if (ConstantPointerRef *CPR =
dyn_cast<ConstantPointerRef>(Callee->use_back()))
if (CPR->use_empty())
CPR->destroyConstant();
// If we inlined the last possible call site to the function,
// delete the function body now.
if (Callee->use_empty() && Callee != Caller &&
(Callee->hasInternalLinkage() || Callee->hasLinkOnceLinkage())) {
DEBUG(std::cerr << " -> Deleting dead function: "
<< (void*)Callee << Callee->getName() << "\n");
std::set<Function*>::iterator I = SCCFunctions.find(Callee);
if (I != SCCFunctions.end()) // Remove function from this SCC.
SCCFunctions.erase(I);
Callee->getParent()->getFunctionList().erase(Callee);
++NumDeleted;
}
Changed = true;
}
}
}
}
return Changed;
}