[llvm-commits] [llvm] r40486 - in /llvm/trunk: include/llvm/Transforms/Utils/BasicInliner.h include/llvm/Transforms/Utils/InlineCost.h lib/Transforms/IPO/InlineSimple.cpp lib/Transforms/Utils/BasicInliner.cpp lib/Transforms/Utils/InlineCost.cpp
Devang Patel
dpatel at apple.com
Wed Jul 25 11:00:26 PDT 2007
Author: dpatel
Date: Wed Jul 25 13:00:25 2007
New Revision: 40486
URL: http://llvm.org/viewvc/llvm-project?rev=40486&view=rev
Log:
Add BasicInliner interface.
This interface allows clients to inline bunch of functions with module
level call graph information.:wq
Added:
llvm/trunk/include/llvm/Transforms/Utils/BasicInliner.h
llvm/trunk/include/llvm/Transforms/Utils/InlineCost.h
llvm/trunk/lib/Transforms/Utils/BasicInliner.cpp
llvm/trunk/lib/Transforms/Utils/InlineCost.cpp
Modified:
llvm/trunk/lib/Transforms/IPO/InlineSimple.cpp
Added: llvm/trunk/include/llvm/Transforms/Utils/BasicInliner.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/BasicInliner.h?rev=40486&view=auto
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/BasicInliner.h (added)
+++ llvm/trunk/include/llvm/Transforms/Utils/BasicInliner.h Wed Jul 25 13:00:25 2007
@@ -0,0 +1,55 @@
+//===- BasicInliner.h - Basic function level inliner ------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Devang Patel and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a simple function based inliner that does not use
+// call graph information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef BASICINLINER_H
+#define BASICINLINER_H
+
+#include "llvm/Transforms/Utils/InlineCost.h"
+
+namespace llvm {
+
+ class Function;
+ class TargetData;
+ class BasicInlinerImpl;
+
+ /// BasicInliner - BasicInliner provides function level inlining interface.
+ /// Clients provide list of functions which are inline without using
+ /// module level call graph information. Note that the BasicInliner is
+ /// free to delete a function if it is inlined into all call sites.
+ class BasicInliner {
+ public:
+
+ BasicInliner(TargetData *T = NULL);
+ ~BasicInliner();
+
+ /// addFunction - Add function into the list of functions to process.
+ /// All functions must be inserted using this interface before invoking
+ /// inlineFunctions().
+ void addFunction(Function *F);
+
+ /// neverInlineFunction - Sometimes a function is never to be inlined
+ /// because of one or other reason.
+ void neverInlineFunction(Function *F);
+
+ /// inlineFuctions - Walk all call sites in all functions supplied by
+ /// client. Inline as many call sites as possible. Delete completely
+ /// inlined functions.
+ void inlineFunctions();
+
+ private:
+ BasicInlinerImpl *Impl;
+ };
+}
+
+#endif
Added: llvm/trunk/include/llvm/Transforms/Utils/InlineCost.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/InlineCost.h?rev=40486&view=auto
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/InlineCost.h (added)
+++ llvm/trunk/include/llvm/Transforms/Utils/InlineCost.h Wed Jul 25 13:00:25 2007
@@ -0,0 +1,80 @@
+//===- InlineCost.cpp - Cost analysis for inliner ---------------*- C++ -*-===//
+//
+// 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 bottom-up inlining of functions into callees.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef INLINECOST_H
+#define INLINECOST_H
+
+#include <set>
+#include <map>
+#include <vector>
+
+namespace llvm {
+
+ class Value;
+ class Function;
+ class CallSite;
+
+ /// InlineCostAnalyzer - Cost analyzer used by inliner.
+ class InlineCostAnalyzer {
+ struct ArgInfo {
+ public:
+ unsigned ConstantWeight;
+ unsigned AllocaWeight;
+
+ ArgInfo(unsigned CWeight, unsigned AWeight)
+ : ConstantWeight(CWeight), AllocaWeight(AWeight) {}
+ };
+
+ // FunctionInfo - For each function, calculate the size of it in blocks and
+ // instructions.
+ struct FunctionInfo {
+ // NumInsts, NumBlocks - Keep track of how large each function is, which is
+ // used to estimate the code size cost of inlining it.
+ unsigned NumInsts, NumBlocks;
+
+ // ArgumentWeights - Each formal argument of the function is inspected to
+ // see if it is used in any contexts where making it a constant or alloca
+ // would reduce the code size. If so, we add some value to the argument
+ // entry here.
+ std::vector<ArgInfo> ArgumentWeights;
+
+ FunctionInfo() : NumInsts(0), NumBlocks(0) {}
+
+ /// analyzeFunction - Fill in the current structure with information gleaned
+ /// from the specified function.
+ void analyzeFunction(Function *F);
+
+ // CountCodeReductionForConstant - Figure out an approximation for how many
+ // instructions will be constant folded if the specified value is constant.
+ //
+ unsigned CountCodeReductionForConstant(Value *V);
+
+ // CountCodeReductionForAlloca - Figure out an approximation of how much smaller
+ // the function will be if it is inlined into a context where an argument
+ // becomes an alloca.
+ //
+ unsigned CountCodeReductionForAlloca(Value *V);
+ };
+
+ std::map<const Function *, FunctionInfo>CachedFunctionInfo;
+
+ public:
+
+ // getInlineCost - The heuristic used to determine if we should inline the
+ // function call or not.
+ //
+ int getInlineCost(CallSite CS, std::set<const Function *> &NeverInline);
+ };
+}
+
+#endif
Modified: llvm/trunk/lib/Transforms/IPO/InlineSimple.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/InlineSimple.cpp?rev=40486&r1=40485&r2=40486&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/InlineSimple.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/InlineSimple.cpp Wed Jul 25 13:00:25 2007
@@ -22,46 +22,22 @@
#include "llvm/Support/Compiler.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/InlinerPass.h"
+#include "llvm/Transforms/Utils/InlineCost.h"
#include <set>
using namespace llvm;
namespace {
- struct VISIBILITY_HIDDEN ArgInfo {
- unsigned ConstantWeight;
- unsigned AllocaWeight;
-
- ArgInfo(unsigned CWeight, unsigned AWeight)
- : ConstantWeight(CWeight), AllocaWeight(AWeight) {}
- };
-
- // FunctionInfo - For each function, calculate the size of it in blocks and
- // instructions.
- struct VISIBILITY_HIDDEN FunctionInfo {
- // NumInsts, NumBlocks - Keep track of how large each function is, which is
- // used to estimate the code size cost of inlining it.
- unsigned NumInsts, NumBlocks;
-
- // ArgumentWeights - Each formal argument of the function is inspected to
- // see if it is used in any contexts where making it a constant or alloca
- // would reduce the code size. If so, we add some value to the argument
- // entry here.
- std::vector<ArgInfo> ArgumentWeights;
-
- FunctionInfo() : NumInsts(0), NumBlocks(0) {}
-
- /// analyzeFunction - Fill in the current structure with information gleaned
- /// from the specified function.
- void analyzeFunction(Function *F);
- };
class VISIBILITY_HIDDEN SimpleInliner : public Inliner {
- std::map<const Function*, FunctionInfo> CachedFunctionInfo;
std::set<const Function*> NeverInline; // Functions that are never inlined
+ InlineCostAnalyzer CA;
public:
SimpleInliner() : Inliner(&ID) {}
static char ID; // Pass identification, replacement for typeid
- int getInlineCost(CallSite CS);
+ int getInlineCost(CallSite CS) {
+ return CA.getInlineCost(CS, NeverInline);
+ }
virtual bool doInitialization(CallGraph &CG);
};
char SimpleInliner::ID = 0;
@@ -70,223 +46,6 @@
Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
-// CountCodeReductionForConstant - Figure out an approximation for how many
-// instructions will be constant folded if the specified value is constant.
-//
-static unsigned CountCodeReductionForConstant(Value *V) {
- unsigned Reduction = 0;
- for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI)
- if (isa<BranchInst>(*UI))
- Reduction += 40; // Eliminating a conditional branch is a big win
- else if (SwitchInst *SI = dyn_cast<SwitchInst>(*UI))
- // Eliminating a switch is a big win, proportional to the number of edges
- // deleted.
- Reduction += (SI->getNumSuccessors()-1) * 40;
- else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
- // Turning an indirect call into a direct call is a BIG win
- Reduction += CI->getCalledValue() == V ? 500 : 0;
- } else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) {
- // Turning an indirect call into a direct call is a BIG win
- Reduction += II->getCalledValue() == V ? 500 : 0;
- } else {
- // Figure out if this instruction will be removed due to simple constant
- // propagation.
- Instruction &Inst = cast<Instruction>(**UI);
- bool AllOperandsConstant = true;
- for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
- if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
- AllOperandsConstant = false;
- break;
- }
-
- if (AllOperandsConstant) {
- // We will get to remove this instruction...
- Reduction += 7;
-
- // And any other instructions that use it which become constants
- // themselves.
- Reduction += CountCodeReductionForConstant(&Inst);
- }
- }
-
- return Reduction;
-}
-
-// CountCodeReductionForAlloca - Figure out an approximation of how much smaller
-// the function will be if it is inlined into a context where an argument
-// becomes an alloca.
-//
-static unsigned CountCodeReductionForAlloca(Value *V) {
- if (!isa<PointerType>(V->getType())) return 0; // Not a pointer
- unsigned Reduction = 0;
- for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
- Instruction *I = cast<Instruction>(*UI);
- if (isa<LoadInst>(I) || isa<StoreInst>(I))
- Reduction += 10;
- else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
- // If the GEP has variable indices, we won't be able to do much with it.
- for (Instruction::op_iterator I = GEP->op_begin()+1, E = GEP->op_end();
- I != E; ++I)
- if (!isa<Constant>(*I)) return 0;
- Reduction += CountCodeReductionForAlloca(GEP)+15;
- } else {
- // If there is some other strange instruction, we're not going to be able
- // to do much if we inline this.
- return 0;
- }
- }
-
- return Reduction;
-}
-
-/// analyzeFunction - Fill in the current structure with information gleaned
-/// from the specified function.
-void FunctionInfo::analyzeFunction(Function *F) {
- unsigned NumInsts = 0, NumBlocks = 0;
-
- // Look at the size of the callee. Each basic block counts as 20 units, and
- // each instruction counts as 10.
- for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
- for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
- II != E; ++II) {
- if (isa<DbgInfoIntrinsic>(II)) continue; // Debug intrinsics don't count.
-
- // Noop casts, including ptr <-> int, don't count.
- if (const CastInst *CI = dyn_cast<CastInst>(II)) {
- if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) ||
- isa<PtrToIntInst>(CI))
- continue;
- } else if (const GetElementPtrInst *GEPI =
- dyn_cast<GetElementPtrInst>(II)) {
- // If a GEP has all constant indices, it will probably be folded with
- // a load/store.
- bool AllConstant = true;
- for (unsigned i = 1, e = GEPI->getNumOperands(); i != e; ++i)
- if (!isa<ConstantInt>(GEPI->getOperand(i))) {
- AllConstant = false;
- break;
- }
- if (AllConstant) continue;
- }
-
- ++NumInsts;
- }
-
- ++NumBlocks;
- }
-
- this->NumBlocks = NumBlocks;
- this->NumInsts = NumInsts;
-
- // Check out all of the arguments to the function, figuring out how much
- // code can be eliminated if one of the arguments is a constant.
- for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
- ArgumentWeights.push_back(ArgInfo(CountCodeReductionForConstant(I),
- CountCodeReductionForAlloca(I)));
-}
-
-
-// getInlineCost - The heuristic used to determine if we should inline the
-// function call or not.
-//
-int SimpleInliner::getInlineCost(CallSite CS) {
- Instruction *TheCall = CS.getInstruction();
- Function *Callee = CS.getCalledFunction();
- const Function *Caller = TheCall->getParent()->getParent();
-
- // Don't inline a directly recursive call.
- if (Caller == Callee ||
- // Don't inline functions which can be redefined at link-time to mean
- // something else. link-once linkage is ok though.
- Callee->hasWeakLinkage() ||
-
- // Don't inline functions marked noinline.
- NeverInline.count(Callee))
- return 2000000000;
-
- // InlineCost - This value measures how good of an inline candidate this call
- // site is to inline. A lower inline cost make is more likely for the call to
- // be inlined. This value may go negative.
- //
- int InlineCost = 0;
-
- // If there is only one call of the function, and it has internal linkage,
- // make it almost guaranteed to be inlined.
- //
- if (Callee->hasInternalLinkage() && Callee->hasOneUse())
- InlineCost -= 30000;
-
- // If this function uses the coldcc calling convention, prefer not to inline
- // it.
- if (Callee->getCallingConv() == CallingConv::Cold)
- InlineCost += 2000;
-
- // If the instruction after the call, or if the normal destination of the
- // invoke is an unreachable instruction, the function is noreturn. As such,
- // there is little point in inlining this.
- if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
- if (isa<UnreachableInst>(II->getNormalDest()->begin()))
- InlineCost += 10000;
- } else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall)))
- InlineCost += 10000;
-
- // Get information about the callee...
- FunctionInfo &CalleeFI = CachedFunctionInfo[Callee];
-
- // If we haven't calculated this information yet, do so now.
- if (CalleeFI.NumBlocks == 0)
- CalleeFI.analyzeFunction(Callee);
-
- // Add to the inline quality for properties that make the call valuable to
- // inline. This includes factors that indicate that the result of inlining
- // the function will be optimizable. Currently this just looks at arguments
- // passed into the function.
- //
- unsigned ArgNo = 0;
- for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
- I != E; ++I, ++ArgNo) {
- // Each argument passed in has a cost at both the caller and the callee
- // sides. This favors functions that take many arguments over functions
- // that take few arguments.
- InlineCost -= 20;
-
- // If this is a function being passed in, it is very likely that we will be
- // able to turn an indirect function call into a direct function call.
- if (isa<Function>(I))
- InlineCost -= 100;
-
- // If an alloca is passed in, inlining this function is likely to allow
- // significant future optimization possibilities (like scalar promotion, and
- // scalarization), so encourage the inlining of the function.
- //
- else if (isa<AllocaInst>(I)) {
- if (ArgNo < CalleeFI.ArgumentWeights.size())
- InlineCost -= CalleeFI.ArgumentWeights[ArgNo].AllocaWeight;
-
- // If this is a constant being passed into the function, use the argument
- // weights calculated for the callee to determine how much will be folded
- // away with this information.
- } else if (isa<Constant>(I)) {
- if (ArgNo < CalleeFI.ArgumentWeights.size())
- InlineCost -= CalleeFI.ArgumentWeights[ArgNo].ConstantWeight;
- }
- }
-
- // Now that we have considered all of the factors that make the call site more
- // likely to be inlined, look at factors that make us not want to inline it.
-
- // Don't inline into something too big, which would make it bigger. Here, we
- // count each basic block as a single unit.
- //
- InlineCost += Caller->size()/20;
-
-
- // Look at the size of the callee. Each basic block counts as 20 units, and
- // each instruction counts as 5.
- InlineCost += CalleeFI.NumInsts*5 + CalleeFI.NumBlocks*20;
- return InlineCost;
-}
-
// doInitialization - Initializes the vector of functions that have been
// annotated with the noinline attribute.
bool SimpleInliner::doInitialization(CallGraph &CG) {
@@ -321,3 +80,4 @@
return false;
}
+
Added: llvm/trunk/lib/Transforms/Utils/BasicInliner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BasicInliner.cpp?rev=40486&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/BasicInliner.cpp (added)
+++ llvm/trunk/lib/Transforms/Utils/BasicInliner.cpp Wed Jul 25 13:00:25 2007
@@ -0,0 +1,171 @@
+//===- BasicInliner.cpp - Basic function level inliner --------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Devang Patel and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a simple function based inliner that does not use
+// call graph information.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "basicinliner"
+
+#include "llvm/Module.h"
+#include "llvm/Function.h"
+#include "llvm/Transforms/Utils/BasicInliner.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include <vector>
+#include <set>
+
+using namespace llvm;
+
+namespace {
+ cl::opt<unsigned>
+ BasicInlineThreshold("inline-threshold", cl::Hidden, cl::init(200),
+ cl::desc("Control the amount of basic inlining to perform (default = 200)"));
+}
+
+namespace llvm {
+
+ /// BasicInlinerImpl - BasicInliner implemantation class. This hides
+ /// container info, used by basic inliner, from public interface.
+ struct VISIBILITY_HIDDEN BasicInlinerImpl {
+
+ BasicInlinerImpl(const BasicInlinerImpl&); // DO NOT IMPLEMENT
+ void operator=(const BasicInlinerImpl&); // DO NO IMPLEMENT
+ public:
+ BasicInlinerImpl(TargetData *T) : TD(T) {}
+
+ /// addFunction - Add function into the list of functions to process.
+ /// All functions must be inserted using this interface before invoking
+ /// inlineFunctions().
+ void addFunction(Function *F) {
+ Functions.push_back(F);
+ }
+
+ /// neverInlineFunction - Sometimes a function is never to be inlined
+ /// because of one or other reason.
+ void neverInlineFunction(Function *F) {
+ NeverInline.insert(F);
+ }
+
+ /// inlineFuctions - Walk all call sites in all functions supplied by
+ /// client. Inline as many call sites as possible. Delete completely
+ /// inlined functions.
+ void inlineFunctions();
+
+ private:
+ TargetData *TD;
+ std::vector<Function *> Functions;
+ std::set<const Function *> NeverInline;
+ SmallPtrSet<Function *, 8> DeadFunctions;
+ InlineCostAnalyzer CA;
+ };
+
+/// inlineFuctions - Walk all call sites in all functions supplied by
+/// client. Inline as many call sites as possible. Delete completely
+/// inlined functions.
+void BasicInlinerImpl::inlineFunctions() {
+
+ // 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
+ // from inlining other functions.
+ std::vector<CallSite> CallSites;
+
+ for (std::vector<Function *>::iterator FI = Functions.begin(),
+ FE = Functions.end(); FI != FE; ++FI) {
+ Function *F = *FI;
+ 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()->isDeclaration())
+ CallSites.push_back(CS);
+ }
+ }
+
+ DOUT << ": " << CallSites.size() << " call sites.\n";
+
+ // Inline call sites.
+ bool Changed = false;
+ do {
+ Changed = false;
+ for (unsigned index = 0; index != CallSites.size() && !CallSites.empty(); ++index) {
+ CallSite CS = CallSites[index];
+ if (Function *Callee = CS.getCalledFunction()) {
+
+ // Eliminate calls taht are never inlinable.
+ if (Callee->isDeclaration() ||
+ CS.getInstruction()->getParent()->getParent() == Callee) {
+ CallSites.erase(CallSites.begin() + index);
+ --index;
+ continue;
+ }
+ int InlineCost = CA.getInlineCost(CS, NeverInline);
+ if (InlineCost >= (int) BasicInlineThreshold) {
+ DOUT << " NOT Inlining: cost = " << InlineCost
+ << ", call: " << *CS.getInstruction();
+ continue;
+ }
+
+ DOUT << " Inlining: cost=" << InlineCost
+ <<", call: " << *CS.getInstruction();
+
+ // Inline
+ if (InlineFunction(CS, NULL, TD)) {
+ if (Callee->use_empty() && Callee->hasInternalLinkage())
+ DeadFunctions.insert(Callee);
+ Changed = true;
+ CallSites.erase(CallSites.begin() + index);
+ --index;
+ }
+ }
+ }
+ } while (Changed);
+
+ // Remove completely inlined functions from module.
+ for(SmallPtrSet<Function *, 8>::iterator I = DeadFunctions.begin(),
+ E = DeadFunctions.end(); I != E; ++I) {
+ Function *D = *I;
+ Module *M = D->getParent();
+ M->getFunctionList().remove(D);
+ }
+}
+
+BasicInliner::BasicInliner(TargetData *TD) {
+ Impl = new BasicInlinerImpl(TD);
+}
+
+BasicInliner::~BasicInliner() {
+ delete Impl;
+}
+
+/// addFunction - Add function into the list of functions to process.
+/// All functions must be inserted using this interface before invoking
+/// inlineFunctions().
+void BasicInliner::addFunction(Function *F) {
+ Impl->addFunction(F);
+}
+
+/// neverInlineFunction - Sometimes a function is never to be inlined because
+/// of one or other reason.
+void BasicInliner::neverInlineFunction(Function *F) {
+ Impl->neverInlineFunction(F);
+}
+
+/// inlineFuctions - Walk all call sites in all functions supplied by
+/// client. Inline as many call sites as possible. Delete completely
+/// inlined functions.
+void BasicInliner::inlineFunctions() {
+ Impl->inlineFunctions();
+}
+
+}
Added: llvm/trunk/lib/Transforms/Utils/InlineCost.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/InlineCost.cpp?rev=40486&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/InlineCost.cpp (added)
+++ llvm/trunk/lib/Transforms/Utils/InlineCost.cpp Wed Jul 25 13:00:25 2007
@@ -0,0 +1,241 @@
+//===- InlineCoast.cpp - Cost analysis for inliner ------------------------===//
+//
+// 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 inline cost analysis.
+//
+//===----------------------------------------------------------------------===//
+
+
+#include "llvm/Transforms/Utils/InlineCost.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/CallingConv.h"
+#include "llvm/IntrinsicInst.h"
+
+using namespace llvm;
+
+// CountCodeReductionForConstant - Figure out an approximation for how many
+// instructions will be constant folded if the specified value is constant.
+//
+unsigned InlineCostAnalyzer::FunctionInfo::
+ CountCodeReductionForConstant(Value *V) {
+ unsigned Reduction = 0;
+ for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI)
+ if (isa<BranchInst>(*UI))
+ Reduction += 40; // Eliminating a conditional branch is a big win
+ else if (SwitchInst *SI = dyn_cast<SwitchInst>(*UI))
+ // Eliminating a switch is a big win, proportional to the number of edges
+ // deleted.
+ Reduction += (SI->getNumSuccessors()-1) * 40;
+ else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
+ // Turning an indirect call into a direct call is a BIG win
+ Reduction += CI->getCalledValue() == V ? 500 : 0;
+ } else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) {
+ // Turning an indirect call into a direct call is a BIG win
+ Reduction += II->getCalledValue() == V ? 500 : 0;
+ } else {
+ // Figure out if this instruction will be removed due to simple constant
+ // propagation.
+ Instruction &Inst = cast<Instruction>(**UI);
+ bool AllOperandsConstant = true;
+ for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
+ if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
+ AllOperandsConstant = false;
+ break;
+ }
+
+ if (AllOperandsConstant) {
+ // We will get to remove this instruction...
+ Reduction += 7;
+
+ // And any other instructions that use it which become constants
+ // themselves.
+ Reduction += CountCodeReductionForConstant(&Inst);
+ }
+ }
+
+ return Reduction;
+}
+
+// CountCodeReductionForAlloca - Figure out an approximation of how much smaller
+// the function will be if it is inlined into a context where an argument
+// becomes an alloca.
+//
+unsigned InlineCostAnalyzer::FunctionInfo::
+ CountCodeReductionForAlloca(Value *V) {
+ if (!isa<PointerType>(V->getType())) return 0; // Not a pointer
+ unsigned Reduction = 0;
+ for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
+ Instruction *I = cast<Instruction>(*UI);
+ if (isa<LoadInst>(I) || isa<StoreInst>(I))
+ Reduction += 10;
+ else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
+ // If the GEP has variable indices, we won't be able to do much with it.
+ for (Instruction::op_iterator I = GEP->op_begin()+1, E = GEP->op_end();
+ I != E; ++I)
+ if (!isa<Constant>(*I)) return 0;
+ Reduction += CountCodeReductionForAlloca(GEP)+15;
+ } else {
+ // If there is some other strange instruction, we're not going to be able
+ // to do much if we inline this.
+ return 0;
+ }
+ }
+
+ return Reduction;
+}
+
+/// analyzeFunction - Fill in the current structure with information gleaned
+/// from the specified function.
+void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
+ unsigned NumInsts = 0, NumBlocks = 0;
+
+ // Look at the size of the callee. Each basic block counts as 20 units, and
+ // each instruction counts as 10.
+ for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+ for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
+ II != E; ++II) {
+ if (isa<DbgInfoIntrinsic>(II)) continue; // Debug intrinsics don't count.
+
+ // Noop casts, including ptr <-> int, don't count.
+ if (const CastInst *CI = dyn_cast<CastInst>(II)) {
+ if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) ||
+ isa<PtrToIntInst>(CI))
+ continue;
+ } else if (const GetElementPtrInst *GEPI =
+ dyn_cast<GetElementPtrInst>(II)) {
+ // If a GEP has all constant indices, it will probably be folded with
+ // a load/store.
+ bool AllConstant = true;
+ for (unsigned i = 1, e = GEPI->getNumOperands(); i != e; ++i)
+ if (!isa<ConstantInt>(GEPI->getOperand(i))) {
+ AllConstant = false;
+ break;
+ }
+ if (AllConstant) continue;
+ }
+
+ ++NumInsts;
+ }
+
+ ++NumBlocks;
+ }
+
+ this->NumBlocks = NumBlocks;
+ this->NumInsts = NumInsts;
+
+ // Check out all of the arguments to the function, figuring out how much
+ // code can be eliminated if one of the arguments is a constant.
+ for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
+ ArgumentWeights.push_back(ArgInfo(CountCodeReductionForConstant(I),
+ CountCodeReductionForAlloca(I)));
+}
+
+
+
+// getInlineCost - The heuristic used to determine if we should inline the
+// function call or not.
+//
+int InlineCostAnalyzer::getInlineCost(CallSite CS, std::set<const Function *> &NeverInline) {
+ Instruction *TheCall = CS.getInstruction();
+ Function *Callee = CS.getCalledFunction();
+ const Function *Caller = TheCall->getParent()->getParent();
+
+ // Don't inline a directly recursive call.
+ if (Caller == Callee ||
+ // Don't inline functions which can be redefined at link-time to mean
+ // something else. link-once linkage is ok though.
+ Callee->hasWeakLinkage() ||
+
+ // Don't inline functions marked noinline.
+ NeverInline.count(Callee))
+ return 2000000000;
+
+ // InlineCost - This value measures how good of an inline candidate this call
+ // site is to inline. A lower inline cost make is more likely for the call to
+ // be inlined. This value may go negative.
+ //
+ int InlineCost = 0;
+
+ // If there is only one call of the function, and it has internal linkage,
+ // make it almost guaranteed to be inlined.
+ //
+ if (Callee->hasInternalLinkage() && Callee->hasOneUse())
+ InlineCost -= 30000;
+
+ // If this function uses the coldcc calling convention, prefer not to inline
+ // it.
+ if (Callee->getCallingConv() == CallingConv::Cold)
+ InlineCost += 2000;
+
+ // If the instruction after the call, or if the normal destination of the
+ // invoke is an unreachable instruction, the function is noreturn. As such,
+ // there is little point in inlining this.
+ if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
+ if (isa<UnreachableInst>(II->getNormalDest()->begin()))
+ InlineCost += 10000;
+ } else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall)))
+ InlineCost += 10000;
+
+ // Get information about the callee...
+ FunctionInfo &CalleeFI = CachedFunctionInfo[Callee];
+
+ // If we haven't calculated this information yet, do so now.
+ if (CalleeFI.NumBlocks == 0)
+ CalleeFI.analyzeFunction(Callee);
+
+ // Add to the inline quality for properties that make the call valuable to
+ // inline. This includes factors that indicate that the result of inlining
+ // the function will be optimizable. Currently this just looks at arguments
+ // passed into the function.
+ //
+ unsigned ArgNo = 0;
+ for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
+ I != E; ++I, ++ArgNo) {
+ // Each argument passed in has a cost at both the caller and the callee
+ // sides. This favors functions that take many arguments over functions
+ // that take few arguments.
+ InlineCost -= 20;
+
+ // If this is a function being passed in, it is very likely that we will be
+ // able to turn an indirect function call into a direct function call.
+ if (isa<Function>(I))
+ InlineCost -= 100;
+
+ // If an alloca is passed in, inlining this function is likely to allow
+ // significant future optimization possibilities (like scalar promotion, and
+ // scalarization), so encourage the inlining of the function.
+ //
+ else if (isa<AllocaInst>(I)) {
+ if (ArgNo < CalleeFI.ArgumentWeights.size())
+ InlineCost -= CalleeFI.ArgumentWeights[ArgNo].AllocaWeight;
+
+ // If this is a constant being passed into the function, use the argument
+ // weights calculated for the callee to determine how much will be folded
+ // away with this information.
+ } else if (isa<Constant>(I)) {
+ if (ArgNo < CalleeFI.ArgumentWeights.size())
+ InlineCost -= CalleeFI.ArgumentWeights[ArgNo].ConstantWeight;
+ }
+ }
+
+ // Now that we have considered all of the factors that make the call site more
+ // likely to be inlined, look at factors that make us not want to inline it.
+
+ // Don't inline into something too big, which would make it bigger. Here, we
+ // count each basic block as a single unit.
+ //
+ InlineCost += Caller->size()/20;
+
+
+ // Look at the size of the callee. Each basic block counts as 20 units, and
+ // each instruction counts as 5.
+ InlineCost += CalleeFI.NumInsts*5 + CalleeFI.NumBlocks*20;
+ return InlineCost;
+}
+
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