//===- InlineSimple.cpp - Code to perform simple function inlining --------===//
//
+// The LLVM Compiler Infrastructure
+//
+// This file 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.
//
//===----------------------------------------------------------------------===//
-#include "Inliner.h"
-#include "llvm/Function.h"
-#include "llvm/iMemory.h"
+#define DEBUG_TYPE "inline"
+#include "llvm/CallingConv.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Module.h"
+#include "llvm/Type.h"
+#include "llvm/Analysis/CallGraph.h"
#include "llvm/Support/CallSite.h"
+#include "llvm/Support/Compiler.h"
#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/IPO/InlinerPass.h"
+#include "llvm/Transforms/Utils/InlineCost.h"
+#include "llvm/ADT/SmallPtrSet.h"
-namespace {
- // FunctionInfo - For each function, calculate the size of it in blocks and
- // instructions.
- struct FunctionInfo {
- unsigned NumInsts, NumBlocks;
+using namespace llvm;
- FunctionInfo() : NumInsts(0), NumBlocks(0) {}
- };
+namespace {
- class SimpleInliner : public Inliner {
- std::map<const Function*, FunctionInfo> CachedFunctionInfo;
+ class VISIBILITY_HIDDEN SimpleInliner : public Inliner {
+ // Functions that are never inlined
+ SmallPtrSet<const Function*, 16> NeverInline;
+ InlineCostAnalyzer CA;
public:
- int getInlineCost(CallSite CS);
+ SimpleInliner() : Inliner(&ID) {}
+ static char ID; // Pass identification, replacement for typeid
+ int getInlineCost(CallSite CS) {
+ return CA.getInlineCost(CS, NeverInline);
+ }
+ virtual bool doInitialization(CallGraph &CG);
};
- RegisterOpt<SimpleInliner> X("inline", "Function Integration/Inlining");
+ char SimpleInliner::ID = 0;
+ RegisterPass<SimpleInliner> X("inline", "Function Integration/Inlining");
}
-Pass *createFunctionInliningPass() { return new SimpleInliner(); }
-
-// getInlineCost - The heuristic used to determine if we should inline the
-// function call or not.
-//
-int SimpleInliner::getInlineCost(CallSite CS) {
- Instruction *TheCall = CS.getInstruction();
- const Function *Callee = CS.getCalledFunction();
- const Function *Caller = TheCall->getParent()->getParent();
-
- // Don't inline a directly recursive call.
- if (Caller == 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->hasOneUse() && Callee->hasInternalLinkage())
- InlineCost -= 30000;
-
- // 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.
- //
- for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
- I != E; ++I) {
- // 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 a constant, global variable or alloca is passed in, inlining this
- // function is likely to allow significant future optimization possibilities
- // (constant propagation, scalar promotion, and scalarization), so encourage
- // the inlining of the function.
- //
- else if (isa<Constant>(I) || isa<GlobalVariable>(I) || isa<AllocaInst>(I))
- InlineCost -= 60;
- }
-
- // 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.
- FunctionInfo &CalleeFI = CachedFunctionInfo[Callee];
-
- // If we haven't calculated this information yet...
- if (CalleeFI.NumBlocks == 0) {
- 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 = Callee->begin(), E = Callee->end();
- BB != E; ++BB) {
- NumInsts += BB->size();
- NumBlocks++;
- }
- CalleeFI.NumBlocks = NumBlocks;
- CalleeFI.NumInsts = NumInsts;
+Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
+
+// doInitialization - Initializes the vector of functions that have been
+// annotated with the noinline attribute.
+bool SimpleInliner::doInitialization(CallGraph &CG) {
+
+ Module &M = CG.getModule();
+
+ // Get llvm.noinline
+ GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
+
+ if (GV == 0)
+ return false;
+
+ // Don't crash on invalid code
+ if (!GV->hasInitializer())
+ return false;
+
+ const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
+
+ if (InitList == 0)
+ return false;
+
+ // Iterate over each element and add to the NeverInline set
+ for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+
+ // Get Source
+ const Constant *Elt = InitList->getOperand(i);
+
+ if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
+ if (CE->getOpcode() == Instruction::BitCast)
+ Elt = CE->getOperand(0);
+
+ // Insert into set of functions to never inline
+ if (const Function *F = dyn_cast<Function>(Elt))
+ NeverInline.insert(F);
}
-
- // 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()*2;
-
-
- // Look at the size of the callee. Each basic block counts as 20 units, and
- // each instruction counts as 10.
- InlineCost += CalleeFI.NumInsts*10 + CalleeFI.NumBlocks*20;
- return InlineCost;
+
+ return false;
}
+
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