196 } |
196 } |
197 |
197 |
198 } |
198 } |
199 |
199 |
200 // Eliminate a card mark sequence. p2x is a ConvP2XNode |
200 // Eliminate a card mark sequence. p2x is a ConvP2XNode |
201 void PhaseMacroExpand::eliminate_card_mark(Node *p2x) { |
201 void PhaseMacroExpand::eliminate_card_mark(Node* p2x) { |
202 assert(p2x->Opcode() == Op_CastP2X, "ConvP2XNode required"); |
202 assert(p2x->Opcode() == Op_CastP2X, "ConvP2XNode required"); |
203 Node *shift = p2x->unique_out(); |
203 if (!UseG1GC) { |
204 Node *addp = shift->unique_out(); |
204 // vanilla/CMS post barrier |
205 for (DUIterator_Last jmin, j = addp->last_outs(jmin); j >= jmin; --j) { |
205 Node *shift = p2x->unique_out(); |
206 Node *st = addp->last_out(j); |
206 Node *addp = shift->unique_out(); |
207 assert(st->is_Store(), "store required"); |
207 for (DUIterator_Last jmin, j = addp->last_outs(jmin); j >= jmin; --j) { |
208 _igvn.replace_node(st, st->in(MemNode::Memory)); |
208 Node *st = addp->last_out(j); |
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209 assert(st->is_Store(), "store required"); |
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210 _igvn.replace_node(st, st->in(MemNode::Memory)); |
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211 } |
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212 } else { |
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213 // G1 pre/post barriers |
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214 assert(p2x->outcnt() == 2, "expects 2 users: Xor and URShift nodes"); |
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215 // It could be only one user, URShift node, in Object.clone() instrinsic |
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216 // but the new allocation is passed to arraycopy stub and it could not |
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217 // be scalar replaced. So we don't check the case. |
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218 |
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219 // Remove G1 post barrier. |
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220 |
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221 // Search for CastP2X->Xor->URShift->Cmp path which |
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222 // checks if the store done to a different from the value's region. |
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223 // And replace Cmp with #0 (false) to collapse G1 post barrier. |
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224 Node* xorx = NULL; |
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225 for (DUIterator_Fast imax, i = p2x->fast_outs(imax); i < imax; i++) { |
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226 Node* u = p2x->fast_out(i); |
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227 if (u->Opcode() == Op_XorX) { |
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228 xorx = u; |
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229 break; |
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230 } |
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231 } |
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232 assert(xorx != NULL, "missing G1 post barrier"); |
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233 Node* shift = xorx->unique_out(); |
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234 Node* cmpx = shift->unique_out(); |
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235 assert(cmpx->is_Cmp() && cmpx->unique_out()->is_Bool() && |
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236 cmpx->unique_out()->as_Bool()->_test._test == BoolTest::ne, |
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237 "missing region check in G1 post barrier"); |
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238 _igvn.replace_node(cmpx, makecon(TypeInt::CC_EQ)); |
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239 |
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240 // Remove G1 pre barrier. |
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241 |
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242 // Search "if (marking != 0)" check and set it to "false". |
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243 Node* this_region = p2x->in(0); |
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244 assert(this_region != NULL, ""); |
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245 // There is no G1 pre barrier if previous stored value is NULL |
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246 // (for example, after initialization). |
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247 if (this_region->is_Region() && this_region->req() == 3) { |
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248 int ind = 1; |
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249 if (!this_region->in(ind)->is_IfFalse()) { |
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250 ind = 2; |
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251 } |
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252 if (this_region->in(ind)->is_IfFalse()) { |
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253 Node* bol = this_region->in(ind)->in(0)->in(1); |
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254 assert(bol->is_Bool(), ""); |
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255 cmpx = bol->in(1); |
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256 if (bol->as_Bool()->_test._test == BoolTest::ne && |
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257 cmpx->is_Cmp() && cmpx->in(2) == intcon(0) && |
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258 cmpx->in(1)->is_Load()) { |
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259 Node* adr = cmpx->in(1)->as_Load()->in(MemNode::Address); |
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260 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + |
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261 PtrQueue::byte_offset_of_active()); |
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262 if (adr->is_AddP() && adr->in(AddPNode::Base) == top() && |
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263 adr->in(AddPNode::Address)->Opcode() == Op_ThreadLocal && |
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264 adr->in(AddPNode::Offset) == MakeConX(marking_offset)) { |
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265 _igvn.replace_node(cmpx, makecon(TypeInt::CC_EQ)); |
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266 } |
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267 } |
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268 } |
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269 } |
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270 // Now CastP2X can be removed since it is used only on dead path |
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271 // which currently still alive until igvn optimize it. |
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272 assert(p2x->unique_out()->Opcode() == Op_URShiftX, ""); |
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273 _igvn.replace_node(p2x, top()); |
209 } |
274 } |
210 } |
275 } |
211 |
276 |
212 // Search for a memory operation for the specified memory slice. |
277 // Search for a memory operation for the specified memory slice. |
213 static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) { |
278 static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) { |
758 Node *n = use->last_out(k); |
823 Node *n = use->last_out(k); |
759 uint oc2 = use->outcnt(); |
824 uint oc2 = use->outcnt(); |
760 if (n->is_Store()) { |
825 if (n->is_Store()) { |
761 _igvn.replace_node(n, n->in(MemNode::Memory)); |
826 _igvn.replace_node(n, n->in(MemNode::Memory)); |
762 } else { |
827 } else { |
763 assert( n->Opcode() == Op_CastP2X, "CastP2X required"); |
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764 eliminate_card_mark(n); |
828 eliminate_card_mark(n); |
765 } |
829 } |
766 k -= (oc2 - use->outcnt()); |
830 k -= (oc2 - use->outcnt()); |
767 } |
831 } |
768 } else { |
832 } else { |
769 assert( !use->is_SafePoint(), "safepoint uses must have been already elimiated"); |
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770 assert( use->Opcode() == Op_CastP2X, "CastP2X required"); |
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771 eliminate_card_mark(use); |
833 eliminate_card_mark(use); |
772 } |
834 } |
773 j -= (oc1 - res->outcnt()); |
835 j -= (oc1 - res->outcnt()); |
774 } |
836 } |
775 assert(res->outcnt() == 0, "all uses of allocated objects must be deleted"); |
837 assert(res->outcnt() == 0, "all uses of allocated objects must be deleted"); |