mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-21 03:29:40 +00:00
* Register all Passes git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3015 91177308-0d34-0410-b5e6-96231b3b80d8
268 lines
9.3 KiB
C++
268 lines
9.3 KiB
C++
//===- FunctionInlining.cpp - Code to perform function inlining -----------===//
|
|
//
|
|
// This file implements inlining of functions.
|
|
//
|
|
// Specifically, this:
|
|
// * Exports functionality to inline any function call
|
|
// * Inlines functions that consist of a single basic block
|
|
// * Is able to inline ANY function call
|
|
// . Has a smart heuristic for when to inline a function
|
|
//
|
|
// Notice that:
|
|
// * This pass opens up a lot of opportunities for constant propogation. It
|
|
// is a good idea to to run a constant propogation pass, then a DCE pass
|
|
// sometime after running this pass.
|
|
//
|
|
// FIXME: This pass should transform alloca instructions in the called function
|
|
// into malloc/free pairs!
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Transforms/FunctionInlining.h"
|
|
#include "llvm/Module.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/iTerminators.h"
|
|
#include "llvm/iPHINode.h"
|
|
#include "llvm/iOther.h"
|
|
#include "llvm/Type.h"
|
|
#include "Support/StatisticReporter.h"
|
|
#include <algorithm>
|
|
#include <iostream>
|
|
|
|
static Statistic<> NumInlined("inline\t\t- Number of functions inlined");
|
|
using std::cerr;
|
|
|
|
// RemapInstruction - Convert the instruction operands from referencing the
|
|
// current values into those specified by ValueMap.
|
|
//
|
|
static inline void RemapInstruction(Instruction *I,
|
|
std::map<const Value *, Value*> &ValueMap) {
|
|
|
|
for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
|
|
const Value *Op = I->getOperand(op);
|
|
Value *V = ValueMap[Op];
|
|
if (!V && (isa<GlobalValue>(Op) || isa<Constant>(Op)))
|
|
continue; // Globals and constants don't get relocated
|
|
|
|
if (!V) {
|
|
cerr << "Val = \n" << Op << "Addr = " << (void*)Op;
|
|
cerr << "\nInst = " << I;
|
|
}
|
|
assert(V && "Referenced value not in value map!");
|
|
I->setOperand(op, V);
|
|
}
|
|
}
|
|
|
|
// InlineFunction - This function forcibly inlines the called function into the
|
|
// basic block of the caller. This returns false if it is not possible to
|
|
// inline this call. The program is still in a well defined state if this
|
|
// occurs though.
|
|
//
|
|
// Note that this only does one level of inlining. For example, if the
|
|
// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
|
|
// exists in the instruction stream. Similiarly this will inline a recursive
|
|
// function by one level.
|
|
//
|
|
bool InlineFunction(CallInst *CI) {
|
|
assert(isa<CallInst>(CI) && "InlineFunction only works on CallInst nodes");
|
|
assert(CI->getParent() && "Instruction not embedded in basic block!");
|
|
assert(CI->getParent()->getParent() && "Instruction not in function!");
|
|
|
|
const Function *CalledFunc = CI->getCalledFunction();
|
|
if (CalledFunc == 0 || // Can't inline external function or indirect call!
|
|
CalledFunc->isExternal()) return false;
|
|
|
|
//cerr << "Inlining " << CalledFunc->getName() << " into "
|
|
// << CurrentMeth->getName() << "\n";
|
|
|
|
BasicBlock *OrigBB = CI->getParent();
|
|
|
|
// Call splitBasicBlock - The original basic block now ends at the instruction
|
|
// immediately before the call. The original basic block now ends with an
|
|
// unconditional branch to NewBB, and NewBB starts with the call instruction.
|
|
//
|
|
BasicBlock *NewBB = OrigBB->splitBasicBlock(CI);
|
|
NewBB->setName("InlinedFunctionReturnNode");
|
|
|
|
// Remove (unlink) the CallInst from the start of the new basic block.
|
|
NewBB->getInstList().remove(CI);
|
|
|
|
// If we have a return value generated by this call, convert it into a PHI
|
|
// node that gets values from each of the old RET instructions in the original
|
|
// function.
|
|
//
|
|
PHINode *PHI = 0;
|
|
if (CalledFunc->getReturnType() != Type::VoidTy) {
|
|
PHI = new PHINode(CalledFunc->getReturnType(), CI->getName());
|
|
|
|
// The PHI node should go at the front of the new basic block to merge all
|
|
// possible incoming values.
|
|
//
|
|
NewBB->getInstList().push_front(PHI);
|
|
|
|
// Anything that used the result of the function call should now use the PHI
|
|
// node as their operand.
|
|
//
|
|
CI->replaceAllUsesWith(PHI);
|
|
}
|
|
|
|
// Keep a mapping between the original function's values and the new
|
|
// duplicated code's values. This includes all of: Function arguments,
|
|
// instruction values, constant pool entries, and basic blocks.
|
|
//
|
|
std::map<const Value *, Value*> ValueMap;
|
|
|
|
// Add the function arguments to the mapping: (start counting at 1 to skip the
|
|
// function reference itself)
|
|
//
|
|
Function::const_aiterator PTI = CalledFunc->abegin();
|
|
for (unsigned a = 1, E = CI->getNumOperands(); a != E; ++a, ++PTI)
|
|
ValueMap[PTI] = CI->getOperand(a);
|
|
|
|
ValueMap[NewBB] = NewBB; // Returns get converted to reference NewBB
|
|
|
|
// Loop over all of the basic blocks in the function, inlining them as
|
|
// appropriate. Keep track of the first basic block of the function...
|
|
//
|
|
for (Function::const_iterator BB = CalledFunc->begin();
|
|
BB != CalledFunc->end(); ++BB) {
|
|
assert(BB->getTerminator() && "BasicBlock doesn't have terminator!?!?");
|
|
|
|
// Create a new basic block to copy instructions into!
|
|
BasicBlock *IBB = new BasicBlock("", NewBB->getParent());
|
|
if (BB->hasName()) IBB->setName(BB->getName()+".i"); // .i = inlined once
|
|
|
|
ValueMap[BB] = IBB; // Add basic block mapping.
|
|
|
|
// Make sure to capture the mapping that a return will use...
|
|
// TODO: This assumes that the RET is returning a value computed in the same
|
|
// basic block as the return was issued from!
|
|
//
|
|
const TerminatorInst *TI = BB->getTerminator();
|
|
|
|
// Loop over all instructions copying them over...
|
|
Instruction *NewInst;
|
|
for (BasicBlock::const_iterator II = BB->begin();
|
|
II != --BB->end(); ++II) {
|
|
IBB->getInstList().push_back((NewInst = II->clone()));
|
|
ValueMap[II] = NewInst; // Add instruction map to value.
|
|
if (II->hasName())
|
|
NewInst->setName(II->getName()+".i"); // .i = inlined once
|
|
}
|
|
|
|
// Copy over the terminator now...
|
|
switch (TI->getOpcode()) {
|
|
case Instruction::Ret: {
|
|
const ReturnInst *RI = cast<ReturnInst>(TI);
|
|
|
|
if (PHI) { // The PHI node should include this value!
|
|
assert(RI->getReturnValue() && "Ret should have value!");
|
|
assert(RI->getReturnValue()->getType() == PHI->getType() &&
|
|
"Ret value not consistent in function!");
|
|
PHI->addIncoming((Value*)RI->getReturnValue(),
|
|
(BasicBlock*)cast<BasicBlock>(&*BB));
|
|
}
|
|
|
|
// Add a branch to the code that was after the original Call.
|
|
IBB->getInstList().push_back(new BranchInst(NewBB));
|
|
break;
|
|
}
|
|
case Instruction::Br:
|
|
IBB->getInstList().push_back(TI->clone());
|
|
break;
|
|
|
|
default:
|
|
cerr << "FunctionInlining: Don't know how to handle terminator: " << TI;
|
|
abort();
|
|
}
|
|
}
|
|
|
|
|
|
// Loop over all of the instructions in the function, fixing up operand
|
|
// references as we go. This uses ValueMap to do all the hard work.
|
|
//
|
|
for (Function::const_iterator BB = CalledFunc->begin();
|
|
BB != CalledFunc->end(); ++BB) {
|
|
BasicBlock *NBB = (BasicBlock*)ValueMap[BB];
|
|
|
|
// Loop over all instructions, fixing each one as we find it...
|
|
//
|
|
for (BasicBlock::iterator II = NBB->begin(); II != NBB->end(); ++II)
|
|
RemapInstruction(II, ValueMap);
|
|
}
|
|
|
|
if (PHI) RemapInstruction(PHI, ValueMap); // Fix the PHI node also...
|
|
|
|
// Change the branch that used to go to NewBB to branch to the first basic
|
|
// block of the inlined function.
|
|
//
|
|
TerminatorInst *Br = OrigBB->getTerminator();
|
|
assert(Br && Br->getOpcode() == Instruction::Br &&
|
|
"splitBasicBlock broken!");
|
|
Br->setOperand(0, ValueMap[&CalledFunc->front()]);
|
|
|
|
// Since we are now done with the CallInst, we can finally delete it.
|
|
delete CI;
|
|
return true;
|
|
}
|
|
|
|
static inline bool ShouldInlineFunction(const CallInst *CI, const Function *F) {
|
|
assert(CI->getParent() && CI->getParent()->getParent() &&
|
|
"Call not embedded into a function!");
|
|
|
|
// Don't inline a recursive call.
|
|
if (CI->getParent()->getParent() == F) return false;
|
|
|
|
// Don't inline something too big. This is a really crappy heuristic
|
|
if (F->size() > 3) return false;
|
|
|
|
// Don't inline into something too big. This is a **really** crappy heuristic
|
|
if (CI->getParent()->getParent()->size() > 10) return false;
|
|
|
|
// Go ahead and try just about anything else.
|
|
return true;
|
|
}
|
|
|
|
|
|
static inline bool DoFunctionInlining(BasicBlock *BB) {
|
|
for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
|
|
if (CallInst *CI = dyn_cast<CallInst>(&*I)) {
|
|
// Check to see if we should inline this function
|
|
Function *F = CI->getCalledFunction();
|
|
if (F && ShouldInlineFunction(CI, F)) {
|
|
return InlineFunction(CI);
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// doFunctionInlining - Use a heuristic based approach to inline functions that
|
|
// seem to look good.
|
|
//
|
|
static bool doFunctionInlining(Function &F) {
|
|
bool Changed = false;
|
|
|
|
// Loop through now and inline instructions a basic block at a time...
|
|
for (Function::iterator I = F.begin(); I != F.end(); )
|
|
if (DoFunctionInlining(I)) {
|
|
++NumInlined;
|
|
Changed = true;
|
|
} else {
|
|
++I;
|
|
}
|
|
|
|
return Changed;
|
|
}
|
|
|
|
namespace {
|
|
struct FunctionInlining : public FunctionPass {
|
|
virtual bool runOnFunction(Function &F) {
|
|
return doFunctionInlining(F);
|
|
}
|
|
};
|
|
RegisterPass<FunctionInlining> X("inline", "Function Integration/Inlining");
|
|
}
|
|
|
|
Pass *createFunctionInliningPass() { return new FunctionInlining(); }
|