-//===- FunctionInlining.cpp - Code to perform function inlining -----------===//
+//===- 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 "llvm/Transforms/IPO.h"
-#include "llvm/Transforms/Utils/Cloning.h"
+#define DEBUG_TYPE "inline"
+#include "llvm/CallingConv.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/iOther.h"
-#include "llvm/iMemory.h"
-#include "Support/Statistic.h"
-#include "Support/CommandLine.h"
-#include <set>
+#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"
+
+using namespace llvm;
namespace {
- Statistic<> NumInlined("inline", "Number of functions inlined");
- 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)"));
- struct FunctionInlining : public Pass {
- virtual bool run(Module &M) {
- bool Changed = false;
- for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
- Changed |= doInlining(I);
- ProcessedFunctions.clear();
- return Changed;
+ class VISIBILITY_HIDDEN SimpleInliner : public Inliner {
+ // Functions that are never inlined
+ SmallPtrSet<const Function*, 16> NeverInline;
+ InlineCostAnalyzer CA;
+ public:
+ SimpleInliner() : Inliner(&ID) {}
+ static char ID; // Pass identification, replacement for typeid
+ int getInlineCost(CallSite CS) {
+ return CA.getInlineCost(CS, NeverInline);
}
-
- private:
- std::set<Function*> ProcessedFunctions; // Prevent infinite recursion
- bool doInlining(Function *F);
+ virtual bool doInitialization(CallGraph &CG);
};
- RegisterOpt<FunctionInlining> X("inline", "Function Integration/Inlining");
+ char SimpleInliner::ID = 0;
+ RegisterPass<SimpleInliner> X("inline", "Function Integration/Inlining");
}
-Pass *createFunctionInliningPass() { return new FunctionInlining(); }
-
-
-// ShouldInlineFunction - The heuristic used to determine if we should inline
-// the function call or not.
-//
-static inline bool ShouldInlineFunction(const CallInst *CI) {
- assert(CI->getParent() && CI->getParent()->getParent() &&
- "Call not embedded into a function!");
-
- const Function *Callee = CI->getCalledFunction();
- if (Callee == 0 || Callee->isExternal())
- return false; // Cannot inline an indirect call... or external function.
-
- // Don't inline a recursive call.
- const Function *Caller = CI->getParent()->getParent();
- if (Caller == Callee) return false;
-
- // InlineQuality - This value measures how good of an inline candidate this
- // call site is to inline. The initial value determines how aggressive the
- // inliner is. If this value is negative after the final computation,
- // inlining is not performed.
- //
- int InlineQuality = InlineLimit;
-
- // If there is only one call of the function, and it has internal linkage,
- // make it almost guaranteed to be inlined.
- //
- if (Callee->use_size() == 1 && Callee->hasInternalLinkage())
- InlineQuality += 30000;
-
- // Add to the inline quality for properties that make the call valueable 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 (User::const_op_iterator I = CI->op_begin()+1, E = CI->op_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.
- InlineQuality += 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))
- InlineQuality += 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))
- InlineQuality += 60;
+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);
}
-
- // 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.
- // As soon as the inline quality gets negative, bail out.
-
- // 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) {
- InlineQuality -= BB->size()*10 + 20;
- if (InlineQuality < 0) return false;
- }
-
- // Don't inline into something too big, which would make it bigger. Here, we
- // count each basic block as a single unit.
- for (Function::const_iterator BB = Caller->begin(), E = Caller->end();
- BB != E; ++BB) {
- --InlineQuality;
- if (InlineQuality < 0) return false;
- }
-
- // If we get here, this call site is high enough "quality" to inline.
- DEBUG(std::cerr << "Inlining in '" << Caller->getName()
- << "', quality = " << InlineQuality << ": " << *CI);
- return true;
-}
-
-
-// doInlining - Use a heuristic based approach to inline functions that seem to
-// look good.
-//
-bool FunctionInlining::doInlining(Function *F) {
- // If we have already processed this function (ie, it is recursive) don't
- // revisit.
- std::set<Function*>::iterator PFI = ProcessedFunctions.lower_bound(F);
- if (PFI != ProcessedFunctions.end() && *PFI == F) return false;
-
- // Insert the function in the set so it doesn't get revisited.
- ProcessedFunctions.insert(PFI, F);
-
- bool Changed = false;
- for (Function::iterator BB = F->begin(); BB != F->end(); ++BB)
- for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
- bool ShouldInc = true;
- // Found a call instruction? FIXME: This should also handle INVOKEs
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- if (Function *Callee = CI->getCalledFunction())
- doInlining(Callee); // Inline in callees before callers!
-
- // Decide whether we should inline this function...
- if (ShouldInlineFunction(CI)) {
- // Save an iterator to the instruction before the call if it exists,
- // otherwise get an iterator at the end of the block... because the
- // call will be destroyed.
- //
- BasicBlock::iterator SI;
- if (I != BB->begin()) {
- SI = I; --SI; // Instruction before the call...
- } else {
- SI = BB->end();
- }
-
- // Attempt to inline the function...
- if (InlineFunction(CI)) {
- ++NumInlined;
- Changed = true;
- // Move to instruction before the call...
- I = (SI == BB->end()) ? BB->begin() : SI;
- ShouldInc = false; // Don't increment iterator until next time
- }
- }
- }
- if (ShouldInc) ++I;
- }
-
- return Changed;
+
+ return false;
}
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