inline.cpp

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/* Copyright 1994, LongView Technologies L.L.C. $Revision: 1.11 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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*/
# include "incls/_precompiled.incl"

# ifdef COMPILER

# include "incls/_inline.cpp.incl"

  static int msgCost = 0;       // estimated cost of last inlining candidate
  

  void CodeScope::memoizeBlocks(symbolOop sel) {
    // memoize block args so they aren't created for inlined cases
    int top = exprStack->length();
    int argc = sel->arg_count();
    for (int i = 1; i <= argc; i++) {
      PReg* r = exprStack->nth(top - i)->preg();
      if (r->isBlockPReg()) ((BlockPReg*)r)->memoize();
    }
  }

  int InlinedScope::calleeSize(RScope* rs) {
    // try to get the callee's size (in bytes)
    if (!rs->isPICScope()) return 0;    // no info
    RPICScope* ps = (RPICScope*)rs;
    nmethod* inlinee = ps->nm;
    if (inlinee->compiler() == NIC) {
      return 0;         // can't say much about the real code size
    }
    int size = inlinee->instsLen() - oopSize * PrologueSize;
    if (inlinee->isUncommonRecompiled()) {
      // uncommon nmethods are bigger because the contain many more non-
      // inlined sends for all the uncomon cases
      size /= 2;
    }
    return size;
  }
  
  bool CodeScope::calleeTooBig(SendInfo* info, RScope* rs,
                                InlineLimitType limitType) {
    // try to see if the potential inlinee is too big
    int size = calleeSize(rs);
    // NB: continue even if size == 0 to bring current estimated size into play
    assert(limitType >= NormalFnLimit && limitType <= BlockFnLimit,
           "bad limit");
    limitType = InlineLimitType(limitType + NormalFnInstrLimit-NormalFnLimit);
    int cutoff = theCompiler->inlineLimit[limitType];
    int estimated = theCompiler->estimatedSize();
    int limit = theCompiler->inlineLimit[NmInstrLimit];
    // reject if inlinee too large, but correct for well-known cheap messages
    bool bad = size > cutoff &&
      !(info->rcvr->hasKlass() &&
        isCheapMessage(info->sel, info->rcvr->klass()));
    if (bad && estimated + size < limit / 2) {
      // allow inlining if recompilee itself is small (i.e., a forwarder)
      if (recompilee &&
          recompilee->instsLen() - oopSize * PrologueSize < cutoff) {
        bad = false;
      }
    }
    // also reject if est. total size too large (except for ifTrue et al)
    // but don't trust the isCheap thing if we're way over the limit
    bad = bad || estimated + size >= limit;
    if (bad &&
        estimated + size < 2 * limit &&
        (size == 0 || size < cutoff / 8) &&
        info->rcvr->hasKlass() &&
        isReallyCheapMessage(info->sel, info->rcvr->klass())) {
      bad = false;
    }
    if (bad && PrintInlining) {
      lprintf("%*s*not inlining %s: callee too big (%d/%d/%d/%d)\n", depth, "",
              selector_string(info->sel), size, cutoff, estimated, limit);
    }
    if (CompilerDebug && bad && estimated > limit)
      warning("Compiler: (while compiling %s/%s) estimated nmethod size > limit (%ld > %ld)",
               selector_string(theCompiler->key->L.selector),
               selector_string(info->sel), estimated, limit);
    return bad;
  }
  
  bool CodeScope::calleeIsSmall(SendInfo* info, RScope* rs,
                                 InlineLimitType limitType) {
    // try to see if the potential inlinee is small
    int size = calleeSize(rs);
    if (!size) return false;    // no size info
    assert(limitType >= NormalFnLimit && limitType <= BlockFnLimit,
           "bad limit");
    limitType = InlineLimitType(limitType + NormalFnInstrLimit-NormalFnLimit);
    int cutoff = theCompiler->inlineLimit[limitType];
    int estimated = theCompiler->estimatedSize();
    int limit = theCompiler->inlineLimit[NmInstrLimit];
    bool ok = size <= cutoff && estimated + size < limit;
    if (ok && PrintInlining) {
      lprintf("%*s*inlining %s anyway: callee is small (%d/%d/%d/%d)\n",
              depth, "", selector_string(info->sel),
              size, cutoff, estimated, limit);
    }
    return ok;
  }
  
  bool CodeScope::shouldInlineSend(SendInfo* info, RScope* rs, Expr* rcvr,
                                    oop m, InlineLimitType limitType) {
    LookupKey* L = info->L;
    if (!L->selector->is_string()) return false;

    if (isRecursiveCall(m, L->receiverKlass, MaxRecursionUnroll)) {
      info->uninlinable = true;
      return false;
    }
    
    if (limitType == NormalFnLimit) {
      // check args to see if any of them is a block; if so, increase limit
      int top = exprStack->length();
      int argc = symbolOop(L->selector)->arg_count();
      for (int i = argc; i > 0; i--) {
        if (exprStack->nth(top - i)->preg()->isBlockPReg()) {
          limitType = BlockArgFnLimit;
          goto done;
        }
      }
      // check receiver
      if (lookupReceiverIsDelta(L->lookupType)) {
        if (self->preg()->isBlockPReg()) limitType = BlockArgFnLimit;
      } else if (exprStack->nth(top - argc - 1)->preg()->isBlockPReg()) {
        limitType = BlockArgFnLimit;
      }
    }
    
   done:
    if (calleeTooBig(info, rs, limitType)) {
      // register this send as uninlinable
      theCompiler->registerUninlinable(info, limitType, 9999);
      return false;
    }

    // NB: this test comes after calleeTooBig to prevent forced inlining of
    // e.g. a really complicated user-defined '+' for matrices
    if (isCheapMessage(symbolOop(L->selector))) {
      msgCost = costP->cheapSendCost;
      return true;
    }

    int cutoff = theCompiler->inlineLimit[limitType];
    msgCost = sicCost((methodKlass*)m->klass(), this, costP);
    if (info->primFailure &&
        info->nsends < MinPrimFailureInvocations) {
      if (rs->isPICScope() && ((RPICScope*)rs)->sd->isOptimized()) {
        // the fail block send is optimized, it's probably executed frequently
      } else if (rs->isInlinedScope()) {
        // was inlined in previous version, so do it again
      } else {
        // don't inline error block unless trivial or taken often
        if (msgCost > MaxTrivialPrimFailureCost) return false;
        // should also look at block method, not default value:With:
        Klass* map = rcvr->klass()->addr();
        if (map->is_block()) {
          memOop method = ((blockKlass*)map)->value();
          msgCost = sicCost((methodKlass*)method->klass(), this, failCostP);
          // bug: should estimate real length of prim failure; e.g. could
          // have single send (cost 1) but that method sends more and more
          // msgs...i.e. need concept of "being in fail branch" so that
          // no further inlining takes place -- fix this
          if (msgCost > MaxTrivialPrimFailureCost) return false;
        }
      }
    }
    if (msgCost > cutoff) {
      if (calleeIsSmall(info, rs, limitType)) return true;
      theCompiler->registerUninlinable(info, limitType, msgCost);
      return false;
    }
    return true;
  }

  bool CodeScope::shouldInlineBlock(SendInfo* info, RScope* rs,
                                     Expr* rcvr, oop method) {
    return shouldInlineSend(info, rs, rcvr, method, BlockFnLimit);
  }

  bool CodeScope::shouldInlineMethod(SendInfo* info, RScope* rs,
                                      Expr* rcvr, oop meth) {
    return shouldInlineSend(info, rs, rcvr, meth, NormalFnLimit);
  }
  
  Expr* CodeScope::picPredictUnlikely(SendInfo* info,
                                        RUntakenScope* uscope) {
    if (theCompiler->useUncommonTraps &&
        info->primFailure && uscope->isUnlikely()) {
      // this send was never executed in the recompilee
      // only make the send unlikely if it had a chance to execute
      // (If the send isn't a prim failure, don't trust the info --
      // it's unlikely that the method just stops executing in the middle.
      // What probably happened is that recompilation happens before the
      // rest of the method got a chance to execute (e.g. recursion), or it
      // always quit via NLR.  In any case, the compiler can't handle this
      // yet - need to treat it specially similar to endsDead.)
      info->nsends = 0;
      const int MinSends = MinPrimFailureInvocations;
      int count = uscope->caller->invocationCount();
      if (count <= 0) {
        // hack: optimized method has no count, so assume it's > MinSends
        count = MinSends + 1;
      }
      bool makeUncommon = count >= MinSends && uscope->sd->wasNeverExecuted();
      if (PrintInlining) {
        lprintf("%*s*%sPIC-type-predicting %s as never executed\n",
                depth, "", makeUncommon ? "" : "NOT ",
                info->sel->copy_null_terminated());
      }
      if (makeUncommon) {
        return new UnknownExpr(info->rcvr->preg(), NULL, true);
      }
    }
    return info->rcvr;
  }

  Expr* CodeScope::picPredict(SendInfo* info) {
    // check PICs for information
    if (!UsePICRecompilation) return info->rcvr;
    bool canBeUnlikely = theCompiler->useUncommonTraps;
    if (rscope->hasSubScopes(_bci)) {
      RScopeBList* l = rscope->subScopes(_bci);
      if (l->first()->isUntakenScope() && l->length() == 1) {
        return picPredictUnlikely(info, (RUntakenScope*)l->first());
      } else if (info->rcvr->containsUnknown()) {
        if (PrintInlining) {
          lprintf("%*s*PIC-type-predicting %s (%ld maps)\n", depth, "",
                  info->sel->copy_null_terminated(), l->length());
        }
        for (int i = 0; i < l->length(); i++) {
          RScope* r = l->nth(i);
          Expr* expr = r->receiverExpr();
          if (expr->isUnknownExpr()) {
            // untaken real send (from PIC)
          } else if (expr->klass()->addr()->is_block()) {
            // for now, doesn't make sense to predict block maps because of
            // map cloning
            if (PrintInlining) {
              lprintf("%*s*not predicting block map\n", depth, ""); 
            }
            canBeUnlikely = false;
          } else {
            Expr* alreadyThere = info->rcvr->findKlass(expr->klass());
            if (alreadyThere) {
              // generalize to map if only have constant
              if (alreadyThere->isConstantExpr())
                info->rcvr = info->rcvr->mergeWith(expr, NULL);
            } else {
              // add map only if type isn't already present (for splitting)
              info->predicted = true;
              info->rcvr = info->rcvr->mergeWith(expr, NULL);
              if (expr->hasConstant() && l->length() == 1) {
                // check to see if single predicted receiver is true or false;
                // if so, add other boolean to prediction.  Reduces the number
                // of uncommon branches; not doing so appears to be overly
                // aggressive (as observed experimentally)
                oop c = expr->constant();
                if (c == Memory->trueObj &&
                    !info->rcvr->findKlass(as_klassOop(Memory->falseObj->klass()))) {
                  Expr* f = new ConstantExpr(Memory->falseObj, NULL, NULL);
                  info->rcvr = info->rcvr->mergeWith(f, NULL);
                } else if (c == Memory->falseObj &&
                           !info->rcvr->findKlass(as_klassOop(Memory->trueObj->klass()))) {
                  Expr* t = new ConstantExpr(Memory->trueObj, NULL, NULL);
                  info->rcvr = info->rcvr->mergeWith(t, NULL);
                }
              }
            }
          }
        }
      } else {
        // know receiver type precisely
        return info->rcvr;
      }
      // mark unknown branch as unlikely
      UnknownExpr* u = info->rcvr->findUnknown();
      if (u && canBeUnlikely && theCompiler->useUncommonTraps && 
          rscope->isUncommonAt(_bci, false)) {
        info->rcvr = info->rcvr->makeUnknownUnlikely(this);
      }
    } else if (theCompiler->useUncommonTraps &&
               info->primFailure &&
               rscope->isUncommonAt(_bci, true)) {
      // this is the failure send of a primitive, and the failure was made
      // uncommon in the recompilee, and it was never taken, so keep it
      // uncommon
      if (PrintInlining) {
        lprintf("%*s*PIC-type-predicting %s as never executed (2)\n",
                depth, "", info->sel->copy_null_terminated());
      }
      info->rcvr = new UnknownExpr(info->rcvr->preg(), NULL, true);
    }
     
    assert(info->rcvr->preg(), "should have a preg");
    return info->rcvr;
  }

  Expr* CodeScope::typePredict(SendInfo* info) {
    // try static type prediction
    PReg* r = info->rcvr->preg();
    symbolOop sel = info->sel;
    if (sel == VMString[IF_TRUE_] ||
        sel == VMString[IF_FALSE_] ||
        sel == VMString[IF_TRUE_FALSE_] ||
        sel == VMString[IF_FALSE_TRUE_] ||
        sel == VMString[OR]  || sel == VMString[AND] || sel == VMString[NOT]) {
      // boolean message
      if (PrintInlining) {
        lprintf("%*s*type-predicting %s\n", depth, "",
               sel->copy_null_terminated());
      }
      info->predicted = true;
      bool allowUnlikely = theCompiler->useUncommonTraps;
      if (CompilerDeferUncommonBranches &&
          (sel == VMString[IF_TRUE_] ||
           sel == VMString[IF_FALSE_] ||
           sel == VMString[IF_TRUE_FALSE_] ||
           sel == VMString[IF_FALSE_TRUE_])) {
        // these bets are really safe - make uncommon even when recompiling
        // due to uncommon trap (if the ifTrue itself caused the trap,
        // rscope->isUncommonAt will be false, so this is safe)
        allowUnlikely = true;
      }
      if (allowUnlikely) {
        if (rscope->isUncommonAt(_bci, false)) {
          // ok, no uncommon trap here
        } else if (rscope->hasSubScopes(_bci)) {
          // has real send for ifTrue et al. -- must be NIC-compiled
          // make uncommon unlikely if no non-true/false receiver present
          RScopeBList* subs = rscope->subScopes(_bci);
          for (int i = subs->length() - 1; i >= 0; i--) {
            RScope* s = subs->nth(i);
            Expr* rcvr = s->receiverExpr();
            if (rcvr->hasKlass()) {
              Klass* m = rcvr->klass()->addr();
              if (m != Memory->trueObj->klass() &&
                  m != Memory->falseObj->klass()) {
                allowUnlikely = false;
                break;
              }
            }
          }
          if (WizardMode && !allowUnlikely)
            warning("Compiler: non-bool receiver for ifTrue: et al. detected");
        }
        if (allowUnlikely) {
          // make unknown case unlikely despite 
          info->rcvr = info->rcvr->makeUnknownUnlikely(this);
        }
      }
      Expr* rcvr = info->rcvr;
      Expr* t = new ConstantExpr(Memory->trueObj , r, NULL);
      Expr* f = new ConstantExpr(Memory->falseObj, r, NULL);
      // make sure we don't destroy splitting info; only add types if not
      // already present
      if (rcvr->findKlass(as_klassOop(Memory->trueObj->klass())) == NULL)
d135 1
a135 1
      if (rcvr->findKlass(as_klassOop(Memory->falseObj->klass())) == NULL)
d141 7
# endif

---