#include "llvm/Module.h"
#include "llvm/Type.h"
#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/InlineCost.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/DataLayout.h"
#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
namespace {
// AlwaysInliner only inlines functions that are mark as "always inline".
- class VISIBILITY_HIDDEN AlwaysInliner : public Inliner {
- // Functions that are never inlined
- SmallPtrSet<const Function*, 16> NeverInline;
- InlineCostAnalyzer CA;
+ class AlwaysInliner : public Inliner {
public:
- // Use extremely low threshold.
- AlwaysInliner() : Inliner(&ID, -2000000000) {}
- static char ID; // Pass identification, replacement for typeid
- int getInlineCost(CallSite CS) {
- return CA.getInlineCost(CS, NeverInline);
+ // Use extremely low threshold.
+ AlwaysInliner() : Inliner(ID, -2000000000, /*InsertLifetime*/true) {
+ initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
+ }
+ AlwaysInliner(bool InsertLifetime) : Inliner(ID, -2000000000,
+ InsertLifetime) {
+ initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
}
- float getInlineFudgeFactor(CallSite CS) {
- return CA.getInlineFudgeFactor(CS);
+ static char ID; // Pass identification, replacement for typeid
+ virtual InlineCost getInlineCost(CallSite CS);
+ virtual bool doFinalization(CallGraph &CG) {
+ return removeDeadFunctions(CG, /*AlwaysInlineOnly=*/true);
}
virtual bool doInitialization(CallGraph &CG);
};
}
char AlwaysInliner::ID = 0;
-static RegisterPass<AlwaysInliner>
-X("always-inline", "Inliner that handles always_inline functions");
+INITIALIZE_PASS_BEGIN(AlwaysInliner, "always-inline",
+ "Inliner for always_inline functions", false, false)
+INITIALIZE_AG_DEPENDENCY(CallGraph)
+INITIALIZE_PASS_END(AlwaysInliner, "always-inline",
+ "Inliner for always_inline functions", false, false)
Pass *llvm::createAlwaysInlinerPass() { return new AlwaysInliner(); }
-// doInitialization - Initializes the vector of functions that have not
+Pass *llvm::createAlwaysInlinerPass(bool InsertLifetime) {
+ return new AlwaysInliner(InsertLifetime);
+}
+
+/// \brief Minimal filter to detect invalid constructs for inlining.
+static bool isInlineViable(Function &F) {
+ bool ReturnsTwice = F.getFnAttributes().hasReturnsTwiceAttr();
+ for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
+ // Disallow inlining of functions which contain an indirect branch.
+ if (isa<IndirectBrInst>(BI->getTerminator()))
+ return false;
+
+ for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;
+ ++II) {
+ CallSite CS(II);
+ if (!CS)
+ continue;
+
+ // Disallow recursive calls.
+ if (&F == CS.getCalledFunction())
+ return false;
+
+ // Disallow calls which expose returns-twice to a function not previously
+ // attributed as such.
+ if (!ReturnsTwice && CS.isCall() &&
+ cast<CallInst>(CS.getInstruction())->canReturnTwice())
+ return false;
+ }
+ }
+
+ return true;
+}
+
+/// \brief Get the inline cost for the always-inliner.
+///
+/// The always inliner *only* handles functions which are marked with the
+/// attribute to force inlining. As such, it is dramatically simpler and avoids
+/// using the powerful (but expensive) inline cost analysis. Instead it uses
+/// a very simple and boring direct walk of the instructions looking for
+/// impossible-to-inline constructs.
+///
+/// Note, it would be possible to go to some lengths to cache the information
+/// computed here, but as we only expect to do this for relatively few and
+/// small functions which have the explicit attribute to force inlining, it is
+/// likely not worth it in practice.
+InlineCost AlwaysInliner::getInlineCost(CallSite CS) {
+ Function *Callee = CS.getCalledFunction();
+ // We assume indirect calls aren't calling an always-inline function.
+ if (!Callee) return InlineCost::getNever();
+
+ // We can't inline calls to external functions.
+ // FIXME: We shouldn't even get here.
+ if (Callee->isDeclaration()) return InlineCost::getNever();
+
+ // Return never for anything not marked as always inline.
+ if (!Callee->getFnAttributes().hasAlwaysInlineAttr())
+ return InlineCost::getNever();
+
+ // Do some minimal analysis to preclude non-viable functions.
+ if (!isInlineViable(*Callee))
+ return InlineCost::getNever();
+
+ // Otherwise, force inlining.
+ return InlineCost::getAlways();
+}
+
+// doInitialization - Initializes the vector of functions that have not
// been annotated with the "always inline" attribute.
bool AlwaysInliner::doInitialization(CallGraph &CG) {
-
- Module &M = CG.getModule();
-
- for (Module::iterator I = M.begin(), E = M.end();
- I != E; ++I)
- if (!I->isDeclaration() && I->getNotes() != FN_NOTE_AlwaysInline)
- NeverInline.insert(I);
-
return false;
}
-