| File: | jdk/src/hotspot/share/opto/buildOopMap.cpp |
| Warning: | line 117, column 17 Value stored to 'jvms' during its initialization is never read |
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| 1 | /* |
| 2 | * Copyright (c) 2002, 2021, Oracle and/or its affiliates. All rights reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| 13 | * accompanied this code). |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License version |
| 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 18 | * |
| 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| 20 | * or visit www.oracle.com if you need additional information or have any |
| 21 | * questions. |
| 22 | * |
| 23 | */ |
| 24 | |
| 25 | #include "precompiled.hpp" |
| 26 | #include "code/vmreg.inline.hpp" |
| 27 | #include "compiler/oopMap.hpp" |
| 28 | #include "memory/resourceArea.hpp" |
| 29 | #include "opto/addnode.hpp" |
| 30 | #include "opto/callnode.hpp" |
| 31 | #include "opto/compile.hpp" |
| 32 | #include "opto/machnode.hpp" |
| 33 | #include "opto/matcher.hpp" |
| 34 | #include "opto/output.hpp" |
| 35 | #include "opto/phase.hpp" |
| 36 | #include "opto/regalloc.hpp" |
| 37 | #include "opto/rootnode.hpp" |
| 38 | #include "utilities/align.hpp" |
| 39 | |
| 40 | // The functions in this file builds OopMaps after all scheduling is done. |
| 41 | // |
| 42 | // OopMaps contain a list of all registers and stack-slots containing oops (so |
| 43 | // they can be updated by GC). OopMaps also contain a list of derived-pointer |
| 44 | // base-pointer pairs. When the base is moved, the derived pointer moves to |
| 45 | // follow it. Finally, any registers holding callee-save values are also |
| 46 | // recorded. These might contain oops, but only the caller knows. |
| 47 | // |
| 48 | // BuildOopMaps implements a simple forward reaching-defs solution. At each |
| 49 | // GC point we'll have the reaching-def Nodes. If the reaching Nodes are |
| 50 | // typed as pointers (no offset), then they are oops. Pointers+offsets are |
| 51 | // derived pointers, and bases can be found from them. Finally, we'll also |
| 52 | // track reaching callee-save values. Note that a copy of a callee-save value |
| 53 | // "kills" it's source, so that only 1 copy of a callee-save value is alive at |
| 54 | // a time. |
| 55 | // |
| 56 | // We run a simple bitvector liveness pass to help trim out dead oops. Due to |
| 57 | // irreducible loops, we can have a reaching def of an oop that only reaches |
| 58 | // along one path and no way to know if it's valid or not on the other path. |
| 59 | // The bitvectors are quite dense and the liveness pass is fast. |
| 60 | // |
| 61 | // At GC points, we consult this information to build OopMaps. All reaching |
| 62 | // defs typed as oops are added to the OopMap. Only 1 instance of a |
| 63 | // callee-save register can be recorded. For derived pointers, we'll have to |
| 64 | // find and record the register holding the base. |
| 65 | // |
| 66 | // The reaching def's is a simple 1-pass worklist approach. I tried a clever |
| 67 | // breadth-first approach but it was worse (showed O(n^2) in the |
| 68 | // pick-next-block code). |
| 69 | // |
| 70 | // The relevant data is kept in a struct of arrays (it could just as well be |
| 71 | // an array of structs, but the struct-of-arrays is generally a little more |
| 72 | // efficient). The arrays are indexed by register number (including |
| 73 | // stack-slots as registers) and so is bounded by 200 to 300 elements in |
| 74 | // practice. One array will map to a reaching def Node (or NULL for |
| 75 | // conflict/dead). The other array will map to a callee-saved register or |
| 76 | // OptoReg::Bad for not-callee-saved. |
| 77 | |
| 78 | |
| 79 | // Structure to pass around |
| 80 | struct OopFlow : public ResourceObj { |
| 81 | short *_callees; // Array mapping register to callee-saved |
| 82 | Node **_defs; // array mapping register to reaching def |
| 83 | // or NULL if dead/conflict |
| 84 | // OopFlow structs, when not being actively modified, describe the _end_ of |
| 85 | // this block. |
| 86 | Block *_b; // Block for this struct |
| 87 | OopFlow *_next; // Next free OopFlow |
| 88 | // or NULL if dead/conflict |
| 89 | Compile* C; |
| 90 | |
| 91 | OopFlow( short *callees, Node **defs, Compile* c ) : _callees(callees), _defs(defs), |
| 92 | _b(NULL__null), _next(NULL__null), C(c) { } |
| 93 | |
| 94 | // Given reaching-defs for this block start, compute it for this block end |
| 95 | void compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ); |
| 96 | |
| 97 | // Merge these two OopFlows into the 'this' pointer. |
| 98 | void merge( OopFlow *flow, int max_reg ); |
| 99 | |
| 100 | // Copy a 'flow' over an existing flow |
| 101 | void clone( OopFlow *flow, int max_size); |
| 102 | |
| 103 | // Make a new OopFlow from scratch |
| 104 | static OopFlow *make( Arena *A, int max_size, Compile* C ); |
| 105 | |
| 106 | // Build an oopmap from the current flow info |
| 107 | OopMap *build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ); |
| 108 | }; |
| 109 | |
| 110 | // Given reaching-defs for this block start, compute it for this block end |
| 111 | void OopFlow::compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ) { |
| 112 | |
| 113 | for( uint i=0; i<_b->number_of_nodes(); i++ ) { |
| 114 | Node *n = _b->get_node(i); |
| 115 | |
| 116 | if( n->jvms() ) { // Build an OopMap here? |
| 117 | JVMState *jvms = n->jvms(); |
Value stored to 'jvms' during its initialization is never read | |
| 118 | // no map needed for leaf calls |
| 119 | if( n->is_MachSafePoint() && !n->is_MachCallLeaf() ) { |
| 120 | int *live = (int*) (*safehash)[n]; |
| 121 | assert( live, "must find live" )do { if (!(live)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 121, "assert(" "live" ") failed", "must find live"); ::breakpoint (); } } while (0); |
| 122 | n->as_MachSafePoint()->set_oop_map( build_oop_map(n,max_reg,regalloc, live) ); |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | // Assign new reaching def's. |
| 127 | // Note that I padded the _defs and _callees arrays so it's legal |
| 128 | // to index at _defs[OptoReg::Bad]. |
| 129 | OptoReg::Name first = regalloc->get_reg_first(n); |
| 130 | OptoReg::Name second = regalloc->get_reg_second(n); |
| 131 | _defs[first] = n; |
| 132 | _defs[second] = n; |
| 133 | |
| 134 | // Pass callee-save info around copies |
| 135 | int idx = n->is_Copy(); |
| 136 | if( idx ) { // Copies move callee-save info |
| 137 | OptoReg::Name old_first = regalloc->get_reg_first(n->in(idx)); |
| 138 | OptoReg::Name old_second = regalloc->get_reg_second(n->in(idx)); |
| 139 | int tmp_first = _callees[old_first]; |
| 140 | int tmp_second = _callees[old_second]; |
| 141 | _callees[old_first] = OptoReg::Bad; // callee-save is moved, dead in old location |
| 142 | _callees[old_second] = OptoReg::Bad; |
| 143 | _callees[first] = tmp_first; |
| 144 | _callees[second] = tmp_second; |
| 145 | } else if( n->is_Phi() ) { // Phis do not mod callee-saves |
| 146 | assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(1))], "" )do { if (!(_callees[first] == _callees[regalloc->get_reg_first (n->in(1))])) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 146, "assert(" "_callees[first] == _callees[regalloc->get_reg_first(n->in(1))]" ") failed", ""); ::breakpoint(); } } while (0); |
| 147 | assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(1))], "" )do { if (!(_callees[second] == _callees[regalloc->get_reg_second (n->in(1))])) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 147, "assert(" "_callees[second] == _callees[regalloc->get_reg_second(n->in(1))]" ") failed", ""); ::breakpoint(); } } while (0); |
| 148 | assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(n->req()-1))], "" )do { if (!(_callees[first] == _callees[regalloc->get_reg_first (n->in(n->req()-1))])) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 148, "assert(" "_callees[first] == _callees[regalloc->get_reg_first(n->in(n->req()-1))]" ") failed", ""); ::breakpoint(); } } while (0); |
| 149 | assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(n->req()-1))], "" )do { if (!(_callees[second] == _callees[regalloc->get_reg_second (n->in(n->req()-1))])) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 149, "assert(" "_callees[second] == _callees[regalloc->get_reg_second(n->in(n->req()-1))]" ") failed", ""); ::breakpoint(); } } while (0); |
| 150 | } else { |
| 151 | _callees[first] = OptoReg::Bad; // No longer holding a callee-save value |
| 152 | _callees[second] = OptoReg::Bad; |
| 153 | |
| 154 | // Find base case for callee saves |
| 155 | if( n->is_Proj() && n->in(0)->is_Start() ) { |
| 156 | if( OptoReg::is_reg(first) && |
| 157 | regalloc->_matcher.is_save_on_entry(first) ) |
| 158 | _callees[first] = first; |
| 159 | if( OptoReg::is_reg(second) && |
| 160 | regalloc->_matcher.is_save_on_entry(second) ) |
| 161 | _callees[second] = second; |
| 162 | } |
| 163 | } |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | // Merge the given flow into the 'this' flow |
| 168 | void OopFlow::merge( OopFlow *flow, int max_reg ) { |
| 169 | assert( _b == NULL, "merging into a happy flow" )do { if (!(_b == __null)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 169, "assert(" "_b == __null" ") failed", "merging into a happy flow" ); ::breakpoint(); } } while (0); |
| 170 | assert( flow->_b, "this flow is still alive" )do { if (!(flow->_b)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 170, "assert(" "flow->_b" ") failed", "this flow is still alive" ); ::breakpoint(); } } while (0); |
| 171 | assert( flow != this, "no self flow" )do { if (!(flow != this)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 171, "assert(" "flow != this" ") failed", "no self flow"); :: breakpoint(); } } while (0); |
| 172 | |
| 173 | // Do the merge. If there are any differences, drop to 'bottom' which |
| 174 | // is OptoReg::Bad or NULL depending. |
| 175 | for( int i=0; i<max_reg; i++ ) { |
| 176 | // Merge the callee-save's |
| 177 | if( _callees[i] != flow->_callees[i] ) |
| 178 | _callees[i] = OptoReg::Bad; |
| 179 | // Merge the reaching defs |
| 180 | if( _defs[i] != flow->_defs[i] ) |
| 181 | _defs[i] = NULL__null; |
| 182 | } |
| 183 | |
| 184 | } |
| 185 | |
| 186 | void OopFlow::clone( OopFlow *flow, int max_size ) { |
| 187 | _b = flow->_b; |
| 188 | memcpy( _callees, flow->_callees, sizeof(short)*max_size); |
| 189 | memcpy( _defs , flow->_defs , sizeof(Node*)*max_size); |
| 190 | } |
| 191 | |
| 192 | OopFlow *OopFlow::make( Arena *A, int max_size, Compile* C ) { |
| 193 | short *callees = NEW_ARENA_ARRAY(A,short,max_size+1)(short*) (A)->Amalloc((max_size+1) * sizeof(short)); |
| 194 | Node **defs = NEW_ARENA_ARRAY(A,Node*,max_size+1)(Node**) (A)->Amalloc((max_size+1) * sizeof(Node*)); |
| 195 | debug_only( memset(defs,0,(max_size+1)*sizeof(Node*)) )memset(defs,0,(max_size+1)*sizeof(Node*)); |
| 196 | OopFlow *flow = new (A) OopFlow(callees+1, defs+1, C); |
| 197 | assert( &flow->_callees[OptoReg::Bad] == callees, "Ok to index at OptoReg::Bad" )do { if (!(&flow->_callees[OptoReg::Bad] == callees)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 197, "assert(" "&flow->_callees[OptoReg::Bad] == callees" ") failed", "Ok to index at OptoReg::Bad"); ::breakpoint(); } } while (0); |
| 198 | assert( &flow->_defs [OptoReg::Bad] == defs , "Ok to index at OptoReg::Bad" )do { if (!(&flow->_defs [OptoReg::Bad] == defs)) { (*g_assert_poison ) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 198, "assert(" "&flow->_defs [OptoReg::Bad] == defs" ") failed", "Ok to index at OptoReg::Bad"); ::breakpoint(); } } while (0); |
| 199 | return flow; |
| 200 | } |
| 201 | |
| 202 | static int get_live_bit( int *live, int reg ) { |
| 203 | return live[reg>>LogBitsPerInt] & (1<<(reg&(BitsPerInt-1))); } |
| 204 | static void set_live_bit( int *live, int reg ) { |
| 205 | live[reg>>LogBitsPerInt] |= (1<<(reg&(BitsPerInt-1))); } |
| 206 | static void clr_live_bit( int *live, int reg ) { |
| 207 | live[reg>>LogBitsPerInt] &= ~(1<<(reg&(BitsPerInt-1))); } |
| 208 | |
| 209 | // Build an oopmap from the current flow info |
| 210 | OopMap *OopFlow::build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ) { |
| 211 | int framesize = regalloc->_framesize; |
| 212 | int max_inarg_slot = OptoReg::reg2stack(regalloc->_matcher._new_SP); |
| 213 | debug_only( char *dup_check = NEW_RESOURCE_ARRAY(char,OptoReg::stack0());char *dup_check = (char*) resource_allocate_bytes((OptoReg::stack0 ()) * sizeof(char)); memset(dup_check,0,OptoReg::stack0()) |
| 214 | memset(dup_check,0,OptoReg::stack0()) )char *dup_check = (char*) resource_allocate_bytes((OptoReg::stack0 ()) * sizeof(char)); memset(dup_check,0,OptoReg::stack0()); |
| 215 | |
| 216 | OopMap *omap = new OopMap( framesize, max_inarg_slot ); |
| 217 | MachCallNode *mcall = n->is_MachCall() ? n->as_MachCall() : NULL__null; |
| 218 | JVMState* jvms = n->jvms(); |
| 219 | |
| 220 | // For all registers do... |
| 221 | for( int reg=0; reg<max_reg; reg++ ) { |
| 222 | if( get_live_bit(live,reg) == 0 ) |
| 223 | continue; // Ignore if not live |
| 224 | |
| 225 | // %%% C2 can use 2 OptoRegs when the physical register is only one 64bit |
| 226 | // register in that case we'll get an non-concrete register for the second |
| 227 | // half. We only need to tell the map the register once! |
| 228 | // |
| 229 | // However for the moment we disable this change and leave things as they |
| 230 | // were. |
| 231 | |
| 232 | VMReg r = OptoReg::as_VMReg(OptoReg::Name(reg), framesize, max_inarg_slot); |
| 233 | |
| 234 | // See if dead (no reaching def). |
| 235 | Node *def = _defs[reg]; // Get reaching def |
| 236 | assert( def, "since live better have reaching def" )do { if (!(def)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 236, "assert(" "def" ") failed", "since live better have reaching def" ); ::breakpoint(); } } while (0); |
| 237 | |
| 238 | // Classify the reaching def as oop, derived, callee-save, dead, or other |
| 239 | const Type *t = def->bottom_type(); |
| 240 | if( t->isa_oop_ptr() ) { // Oop or derived? |
| 241 | assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" )do { if (!(!OptoReg::is_valid(_callees[reg]))) { (*g_assert_poison ) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 241, "assert(" "!OptoReg::is_valid(_callees[reg])" ") failed" , "oop can't be callee save"); ::breakpoint(); } } while (0); |
| 242 | #ifdef _LP641 |
| 243 | // 64-bit pointers record oop-ishness on 2 aligned adjacent registers. |
| 244 | // Make sure both are record from the same reaching def, but do not |
| 245 | // put both into the oopmap. |
| 246 | if( (reg&1) == 1 ) { // High half of oop-pair? |
| 247 | assert( _defs[reg-1] == _defs[reg], "both halves from same reaching def" )do { if (!(_defs[reg-1] == _defs[reg])) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 247, "assert(" "_defs[reg-1] == _defs[reg]" ") failed", "both halves from same reaching def" ); ::breakpoint(); } } while (0); |
| 248 | continue; // Do not record high parts in oopmap |
| 249 | } |
| 250 | #endif |
| 251 | |
| 252 | // Check for a legal reg name in the oopMap and bailout if it is not. |
| 253 | if (!omap->legal_vm_reg_name(r)) { |
| 254 | regalloc->C->record_method_not_compilable("illegal oopMap register name"); |
| 255 | continue; |
| 256 | } |
| 257 | if( t->is_ptr()->_offset == 0 ) { // Not derived? |
| 258 | if( mcall ) { |
| 259 | // Outgoing argument GC mask responsibility belongs to the callee, |
| 260 | // not the caller. Inspect the inputs to the call, to see if |
| 261 | // this live-range is one of them. |
| 262 | uint cnt = mcall->tf()->domain()->cnt(); |
| 263 | uint j; |
| 264 | for( j = TypeFunc::Parms; j < cnt; j++) |
| 265 | if( mcall->in(j) == def ) |
| 266 | break; // reaching def is an argument oop |
| 267 | if( j < cnt ) // arg oops dont go in GC map |
| 268 | continue; // Continue on to the next register |
| 269 | } |
| 270 | omap->set_oop(r); |
| 271 | } else { // Else it's derived. |
| 272 | // Find the base of the derived value. |
| 273 | uint i; |
| 274 | // Fast, common case, scan |
| 275 | for( i = jvms->oopoff(); i < n->req(); i+=2 ) |
| 276 | if( n->in(i) == def ) break; // Common case |
| 277 | if( i == n->req() ) { // Missed, try a more generous scan |
| 278 | // Scan again, but this time peek through copies |
| 279 | for( i = jvms->oopoff(); i < n->req(); i+=2 ) { |
| 280 | Node *m = n->in(i); // Get initial derived value |
| 281 | while( 1 ) { |
| 282 | Node *d = def; // Get initial reaching def |
| 283 | while( 1 ) { // Follow copies of reaching def to end |
| 284 | if( m == d ) goto found; // breaks 3 loops |
| 285 | int idx = d->is_Copy(); |
| 286 | if( !idx ) break; |
| 287 | d = d->in(idx); // Link through copy |
| 288 | } |
| 289 | int idx = m->is_Copy(); |
| 290 | if( !idx ) break; |
| 291 | m = m->in(idx); |
| 292 | } |
| 293 | } |
| 294 | guarantee( 0, "must find derived/base pair" )do { if (!(0)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 294, "guarantee(" "0" ") failed", "must find derived/base pair" ); ::breakpoint(); } } while (0); |
| 295 | } |
| 296 | found: ; |
| 297 | Node *base = n->in(i+1); // Base is other half of pair |
| 298 | int breg = regalloc->get_reg_first(base); |
| 299 | VMReg b = OptoReg::as_VMReg(OptoReg::Name(breg), framesize, max_inarg_slot); |
| 300 | |
| 301 | // I record liveness at safepoints BEFORE I make the inputs |
| 302 | // live. This is because argument oops are NOT live at a |
| 303 | // safepoint (or at least they cannot appear in the oopmap). |
| 304 | // Thus bases of base/derived pairs might not be in the |
| 305 | // liveness data but they need to appear in the oopmap. |
| 306 | if( get_live_bit(live,breg) == 0 ) {// Not live? |
| 307 | // Flag it, so next derived pointer won't re-insert into oopmap |
| 308 | set_live_bit(live,breg); |
| 309 | // Already missed our turn? |
| 310 | if( breg < reg ) { |
| 311 | omap->set_oop(b); |
| 312 | } |
| 313 | } |
| 314 | omap->set_derived_oop(r, b); |
| 315 | } |
| 316 | |
| 317 | } else if( t->isa_narrowoop() ) { |
| 318 | assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" )do { if (!(!OptoReg::is_valid(_callees[reg]))) { (*g_assert_poison ) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 318, "assert(" "!OptoReg::is_valid(_callees[reg])" ") failed" , "oop can't be callee save"); ::breakpoint(); } } while (0); |
| 319 | // Check for a legal reg name in the oopMap and bailout if it is not. |
| 320 | if (!omap->legal_vm_reg_name(r)) { |
| 321 | regalloc->C->record_method_not_compilable("illegal oopMap register name"); |
| 322 | continue; |
| 323 | } |
| 324 | if( mcall ) { |
| 325 | // Outgoing argument GC mask responsibility belongs to the callee, |
| 326 | // not the caller. Inspect the inputs to the call, to see if |
| 327 | // this live-range is one of them. |
| 328 | uint cnt = mcall->tf()->domain()->cnt(); |
| 329 | uint j; |
| 330 | for( j = TypeFunc::Parms; j < cnt; j++) |
| 331 | if( mcall->in(j) == def ) |
| 332 | break; // reaching def is an argument oop |
| 333 | if( j < cnt ) // arg oops dont go in GC map |
| 334 | continue; // Continue on to the next register |
| 335 | } |
| 336 | omap->set_narrowoop(r); |
| 337 | } else if( OptoReg::is_valid(_callees[reg])) { // callee-save? |
| 338 | // It's a callee-save value |
| 339 | assert( dup_check[_callees[reg]]==0, "trying to callee save same reg twice" )do { if (!(dup_check[_callees[reg]]==0)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 339, "assert(" "dup_check[_callees[reg]]==0" ") failed", "trying to callee save same reg twice" ); ::breakpoint(); } } while (0); |
| 340 | debug_only( dup_check[_callees[reg]]=1; )dup_check[_callees[reg]]=1; |
| 341 | VMReg callee = OptoReg::as_VMReg(OptoReg::Name(_callees[reg])); |
| 342 | omap->set_callee_saved(r, callee); |
| 343 | |
| 344 | } else { |
| 345 | // Other - some reaching non-oop value |
| 346 | #ifdef ASSERT1 |
| 347 | if( t->isa_rawptr() && C->cfg()->_raw_oops.member(def) ) { |
| 348 | def->dump(); |
| 349 | n->dump(); |
| 350 | assert(false, "there should be a oop in OopMap instead of a live raw oop at safepoint")do { if (!(false)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 350, "assert(" "false" ") failed", "there should be a oop in OopMap instead of a live raw oop at safepoint" ); ::breakpoint(); } } while (0); |
| 351 | } |
| 352 | #endif |
| 353 | } |
| 354 | |
| 355 | } |
| 356 | |
| 357 | #ifdef ASSERT1 |
| 358 | /* Nice, Intel-only assert |
| 359 | int cnt_callee_saves=0; |
| 360 | int reg2 = 0; |
| 361 | while (OptoReg::is_reg(reg2)) { |
| 362 | if( dup_check[reg2] != 0) cnt_callee_saves++; |
| 363 | assert( cnt_callee_saves==3 || cnt_callee_saves==5, "missed some callee-save" ); |
| 364 | reg2++; |
| 365 | } |
| 366 | */ |
| 367 | #endif |
| 368 | |
| 369 | #ifdef ASSERT1 |
| 370 | for( OopMapStream oms1(omap); !oms1.is_done(); oms1.next()) { |
| 371 | OopMapValue omv1 = oms1.current(); |
| 372 | if (omv1.type() != OopMapValue::derived_oop_value) { |
| 373 | continue; |
| 374 | } |
| 375 | bool found = false; |
| 376 | for( OopMapStream oms2(omap); !oms2.is_done(); oms2.next()) { |
| 377 | OopMapValue omv2 = oms2.current(); |
| 378 | if (omv2.type() != OopMapValue::oop_value) { |
| 379 | continue; |
| 380 | } |
| 381 | if( omv1.content_reg() == omv2.reg() ) { |
| 382 | found = true; |
| 383 | break; |
| 384 | } |
| 385 | } |
| 386 | assert( found, "derived with no base in oopmap" )do { if (!(found)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 386, "assert(" "found" ") failed", "derived with no base in oopmap" ); ::breakpoint(); } } while (0); |
| 387 | } |
| 388 | #endif |
| 389 | |
| 390 | return omap; |
| 391 | } |
| 392 | |
| 393 | // Compute backwards liveness on registers |
| 394 | static void do_liveness(PhaseRegAlloc* regalloc, PhaseCFG* cfg, Block_List* worklist, int max_reg_ints, Arena* A, Dict* safehash) { |
| 395 | int* live = NEW_ARENA_ARRAY(A, int, (cfg->number_of_blocks() + 1) * max_reg_ints)(int*) (A)->Amalloc(((cfg->number_of_blocks() + 1) * max_reg_ints ) * sizeof(int)); |
| 396 | int* tmp_live = &live[cfg->number_of_blocks() * max_reg_ints]; |
| 397 | Node* root = cfg->get_root_node(); |
| 398 | // On CISC platforms, get the node representing the stack pointer that regalloc |
| 399 | // used for spills |
| 400 | Node *fp = NodeSentinel(Node*)-1; |
| 401 | if (UseCISCSpill && root->req() > 1) { |
| 402 | fp = root->in(1)->in(TypeFunc::FramePtr); |
| 403 | } |
| 404 | memset(live, 0, cfg->number_of_blocks() * (max_reg_ints << LogBytesPerInt)); |
| 405 | // Push preds onto worklist |
| 406 | for (uint i = 1; i < root->req(); i++) { |
| 407 | Block* block = cfg->get_block_for_node(root->in(i)); |
| 408 | worklist->push(block); |
| 409 | } |
| 410 | |
| 411 | // ZKM.jar includes tiny infinite loops which are unreached from below. |
| 412 | // If we missed any blocks, we'll retry here after pushing all missed |
| 413 | // blocks on the worklist. Normally this outer loop never trips more |
| 414 | // than once. |
| 415 | while (1) { |
| 416 | |
| 417 | while( worklist->size() ) { // Standard worklist algorithm |
| 418 | Block *b = worklist->rpop(); |
| 419 | |
| 420 | // Copy first successor into my tmp_live space |
| 421 | int s0num = b->_succs[0]->_pre_order; |
| 422 | int *t = &live[s0num*max_reg_ints]; |
| 423 | for( int i=0; i<max_reg_ints; i++ ) |
| 424 | tmp_live[i] = t[i]; |
| 425 | |
| 426 | // OR in the remaining live registers |
| 427 | for( uint j=1; j<b->_num_succs; j++ ) { |
| 428 | uint sjnum = b->_succs[j]->_pre_order; |
| 429 | int *t = &live[sjnum*max_reg_ints]; |
| 430 | for( int i=0; i<max_reg_ints; i++ ) |
| 431 | tmp_live[i] |= t[i]; |
| 432 | } |
| 433 | |
| 434 | // Now walk tmp_live up the block backwards, computing live |
| 435 | for( int k=b->number_of_nodes()-1; k>=0; k-- ) { |
| 436 | Node *n = b->get_node(k); |
| 437 | // KILL def'd bits |
| 438 | int first = regalloc->get_reg_first(n); |
| 439 | int second = regalloc->get_reg_second(n); |
| 440 | if( OptoReg::is_valid(first) ) clr_live_bit(tmp_live,first); |
| 441 | if( OptoReg::is_valid(second) ) clr_live_bit(tmp_live,second); |
| 442 | |
| 443 | MachNode *m = n->is_Mach() ? n->as_Mach() : NULL__null; |
| 444 | |
| 445 | // Check if m is potentially a CISC alternate instruction (i.e, possibly |
| 446 | // synthesized by RegAlloc from a conventional instruction and a |
| 447 | // spilled input) |
| 448 | bool is_cisc_alternate = false; |
| 449 | if (UseCISCSpill && m) { |
| 450 | is_cisc_alternate = m->is_cisc_alternate(); |
| 451 | } |
| 452 | |
| 453 | // GEN use'd bits |
| 454 | for( uint l=1; l<n->req(); l++ ) { |
| 455 | Node *def = n->in(l); |
| 456 | assert(def != 0, "input edge required")do { if (!(def != 0)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 456, "assert(" "def != 0" ") failed", "input edge required" ); ::breakpoint(); } } while (0); |
| 457 | int first = regalloc->get_reg_first(def); |
| 458 | int second = regalloc->get_reg_second(def); |
| 459 | //If peephole had removed the node,do not set live bit for it. |
| 460 | if (!(def->is_Mach() && def->as_Mach()->get_removed())) { |
| 461 | if (OptoReg::is_valid(first)) set_live_bit(tmp_live,first); |
| 462 | if (OptoReg::is_valid(second)) set_live_bit(tmp_live,second); |
| 463 | } |
| 464 | // If we use the stack pointer in a cisc-alternative instruction, |
| 465 | // check for use as a memory operand. Then reconstruct the RegName |
| 466 | // for this stack location, and set the appropriate bit in the |
| 467 | // live vector 4987749. |
| 468 | if (is_cisc_alternate && def == fp) { |
| 469 | const TypePtr *adr_type = NULL__null; |
| 470 | intptr_t offset; |
| 471 | const Node* base = m->get_base_and_disp(offset, adr_type); |
| 472 | if (base == NodeSentinel(Node*)-1) { |
| 473 | // Machnode has multiple memory inputs. We are unable to reason |
| 474 | // with these, but are presuming (with trepidation) that not any of |
| 475 | // them are oops. This can be fixed by making get_base_and_disp() |
| 476 | // look at a specific input instead of all inputs. |
| 477 | assert(!def->bottom_type()->isa_oop_ptr(), "expecting non-oop mem input")do { if (!(!def->bottom_type()->isa_oop_ptr())) { (*g_assert_poison ) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 477, "assert(" "!def->bottom_type()->isa_oop_ptr()" ") failed" , "expecting non-oop mem input"); ::breakpoint(); } } while ( 0); |
| 478 | } else if (base != fp || offset == Type::OffsetBot) { |
| 479 | // Do nothing: the fp operand is either not from a memory use |
| 480 | // (base == NULL) OR the fp is used in a non-memory context |
| 481 | // (base is some other register) OR the offset is not constant, |
| 482 | // so it is not a stack slot. |
| 483 | } else { |
| 484 | assert(offset >= 0, "unexpected negative offset")do { if (!(offset >= 0)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 484, "assert(" "offset >= 0" ") failed", "unexpected negative offset" ); ::breakpoint(); } } while (0); |
| 485 | offset -= (offset % jintSize); // count the whole word |
| 486 | int stack_reg = regalloc->offset2reg(offset); |
| 487 | if (OptoReg::is_stack(stack_reg)) { |
| 488 | set_live_bit(tmp_live, stack_reg); |
| 489 | } else { |
| 490 | assert(false, "stack_reg not on stack?")do { if (!(false)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 490, "assert(" "false" ") failed", "stack_reg not on stack?" ); ::breakpoint(); } } while (0); |
| 491 | } |
| 492 | } |
| 493 | } |
| 494 | } |
| 495 | |
| 496 | if( n->jvms() ) { // Record liveness at safepoint |
| 497 | |
| 498 | // This placement of this stanza means inputs to calls are |
| 499 | // considered live at the callsite's OopMap. Argument oops are |
| 500 | // hence live, but NOT included in the oopmap. See cutout in |
| 501 | // build_oop_map. Debug oops are live (and in OopMap). |
| 502 | int *n_live = NEW_ARENA_ARRAY(A, int, max_reg_ints)(int*) (A)->Amalloc((max_reg_ints) * sizeof(int)); |
| 503 | for( int l=0; l<max_reg_ints; l++ ) |
| 504 | n_live[l] = tmp_live[l]; |
| 505 | safehash->Insert(n,n_live); |
| 506 | } |
| 507 | |
| 508 | } |
| 509 | |
| 510 | // Now at block top, see if we have any changes. If so, propagate |
| 511 | // to prior blocks. |
| 512 | int *old_live = &live[b->_pre_order*max_reg_ints]; |
| 513 | int l; |
| 514 | for( l=0; l<max_reg_ints; l++ ) |
| 515 | if( tmp_live[l] != old_live[l] ) |
| 516 | break; |
| 517 | if( l<max_reg_ints ) { // Change! |
| 518 | // Copy in new value |
| 519 | for( l=0; l<max_reg_ints; l++ ) |
| 520 | old_live[l] = tmp_live[l]; |
| 521 | // Push preds onto worklist |
| 522 | for (l = 1; l < (int)b->num_preds(); l++) { |
| 523 | Block* block = cfg->get_block_for_node(b->pred(l)); |
| 524 | worklist->push(block); |
| 525 | } |
| 526 | } |
| 527 | } |
| 528 | |
| 529 | // Scan for any missing safepoints. Happens to infinite loops |
| 530 | // ala ZKM.jar |
| 531 | uint i; |
| 532 | for (i = 1; i < cfg->number_of_blocks(); i++) { |
| 533 | Block* block = cfg->get_block(i); |
| 534 | uint j; |
| 535 | for (j = 1; j < block->number_of_nodes(); j++) { |
| 536 | if (block->get_node(j)->jvms() && (*safehash)[block->get_node(j)] == NULL__null) { |
| 537 | break; |
| 538 | } |
| 539 | } |
| 540 | if (j < block->number_of_nodes()) { |
| 541 | break; |
| 542 | } |
| 543 | } |
| 544 | if (i == cfg->number_of_blocks()) { |
| 545 | break; // Got 'em all |
| 546 | } |
| 547 | |
| 548 | if (PrintOpto && Verbose) { |
| 549 | tty->print_cr("retripping live calc"); |
| 550 | } |
| 551 | |
| 552 | // Force the issue (expensively): recheck everybody |
| 553 | for (i = 1; i < cfg->number_of_blocks(); i++) { |
| 554 | worklist->push(cfg->get_block(i)); |
| 555 | } |
| 556 | } |
| 557 | } |
| 558 | |
| 559 | // Collect GC mask info - where are all the OOPs? |
| 560 | void PhaseOutput::BuildOopMaps() { |
| 561 | Compile::TracePhase tp("bldOopMaps", &timers[_t_buildOopMaps]); |
| 562 | // Can't resource-mark because I need to leave all those OopMaps around, |
| 563 | // or else I need to resource-mark some arena other than the default. |
| 564 | // ResourceMark rm; // Reclaim all OopFlows when done |
| 565 | int max_reg = C->regalloc()->_max_reg; // Current array extent |
| 566 | |
| 567 | Arena *A = Thread::current()->resource_area(); |
| 568 | Block_List worklist; // Worklist of pending blocks |
| 569 | |
| 570 | int max_reg_ints = align_up(max_reg, BitsPerInt)>>LogBitsPerInt; |
| 571 | Dict *safehash = NULL__null; // Used for assert only |
| 572 | // Compute a backwards liveness per register. Needs a bitarray of |
| 573 | // #blocks x (#registers, rounded up to ints) |
| 574 | safehash = new Dict(cmpkey,hashkey,A); |
| 575 | do_liveness( C->regalloc(), C->cfg(), &worklist, max_reg_ints, A, safehash ); |
| 576 | OopFlow *free_list = NULL__null; // Free, unused |
| 577 | |
| 578 | // Array mapping blocks to completed oopflows |
| 579 | OopFlow **flows = NEW_ARENA_ARRAY(A, OopFlow*, C->cfg()->number_of_blocks())(OopFlow**) (A)->Amalloc((C->cfg()->number_of_blocks ()) * sizeof(OopFlow*)); |
| 580 | memset( flows, 0, C->cfg()->number_of_blocks() * sizeof(OopFlow*) ); |
| 581 | |
| 582 | |
| 583 | // Do the first block 'by hand' to prime the worklist |
| 584 | Block *entry = C->cfg()->get_block(1); |
| 585 | OopFlow *rootflow = OopFlow::make(A,max_reg,C); |
| 586 | // Initialize to 'bottom' (not 'top') |
| 587 | memset( rootflow->_callees, OptoReg::Bad, max_reg*sizeof(short) ); |
| 588 | memset( rootflow->_defs , 0, max_reg*sizeof(Node*) ); |
| 589 | flows[entry->_pre_order] = rootflow; |
| 590 | |
| 591 | // Do the first block 'by hand' to prime the worklist |
| 592 | rootflow->_b = entry; |
| 593 | rootflow->compute_reach( C->regalloc(), max_reg, safehash ); |
| 594 | for( uint i=0; i<entry->_num_succs; i++ ) |
| 595 | worklist.push(entry->_succs[i]); |
| 596 | |
| 597 | // Now worklist contains blocks which have some, but perhaps not all, |
| 598 | // predecessors visited. |
| 599 | while( worklist.size() ) { |
| 600 | // Scan for a block with all predecessors visited, or any randoms slob |
| 601 | // otherwise. All-preds-visited order allows me to recycle OopFlow |
| 602 | // structures rapidly and cut down on the memory footprint. |
| 603 | // Note: not all predecessors might be visited yet (must happen for |
| 604 | // irreducible loops). This is OK, since every live value must have the |
| 605 | // SAME reaching def for the block, so any reaching def is OK. |
| 606 | uint i; |
| 607 | |
| 608 | Block *b = worklist.pop(); |
| 609 | // Ignore root block |
| 610 | if (b == C->cfg()->get_root_block()) { |
| 611 | continue; |
| 612 | } |
| 613 | // Block is already done? Happens if block has several predecessors, |
| 614 | // he can get on the worklist more than once. |
| 615 | if( flows[b->_pre_order] ) continue; |
| 616 | |
| 617 | // If this block has a visited predecessor AND that predecessor has this |
| 618 | // last block as his only undone child, we can move the OopFlow from the |
| 619 | // pred to this block. Otherwise we have to grab a new OopFlow. |
| 620 | OopFlow *flow = NULL__null; // Flag for finding optimized flow |
| 621 | Block *pred = (Block*)((intptr_t)0xdeadbeef); |
| 622 | // Scan this block's preds to find a done predecessor |
| 623 | for (uint j = 1; j < b->num_preds(); j++) { |
| 624 | Block* p = C->cfg()->get_block_for_node(b->pred(j)); |
| 625 | OopFlow *p_flow = flows[p->_pre_order]; |
| 626 | if( p_flow ) { // Predecessor is done |
| 627 | assert( p_flow->_b == p, "cross check" )do { if (!(p_flow->_b == p)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 627, "assert(" "p_flow->_b == p" ") failed", "cross check" ); ::breakpoint(); } } while (0); |
| 628 | pred = p; // Record some predecessor |
| 629 | // If all successors of p are done except for 'b', then we can carry |
| 630 | // p_flow forward to 'b' without copying, otherwise we have to draw |
| 631 | // from the free_list and clone data. |
| 632 | uint k; |
| 633 | for( k=0; k<p->_num_succs; k++ ) |
| 634 | if( !flows[p->_succs[k]->_pre_order] && |
| 635 | p->_succs[k] != b ) |
| 636 | break; |
| 637 | |
| 638 | // Either carry-forward the now-unused OopFlow for b's use |
| 639 | // or draw a new one from the free list |
| 640 | if( k==p->_num_succs ) { |
| 641 | flow = p_flow; |
| 642 | break; // Found an ideal pred, use him |
| 643 | } |
| 644 | } |
| 645 | } |
| 646 | |
| 647 | if( flow ) { |
| 648 | // We have an OopFlow that's the last-use of a predecessor. |
| 649 | // Carry it forward. |
| 650 | } else { // Draw a new OopFlow from the freelist |
| 651 | if( !free_list ) |
| 652 | free_list = OopFlow::make(A,max_reg,C); |
| 653 | flow = free_list; |
| 654 | assert( flow->_b == NULL, "oopFlow is not free" )do { if (!(flow->_b == __null)) { (*g_assert_poison) = 'X' ;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 654, "assert(" "flow->_b == __null" ") failed", "oopFlow is not free" ); ::breakpoint(); } } while (0); |
| 655 | free_list = flow->_next; |
| 656 | flow->_next = NULL__null; |
| 657 | |
| 658 | // Copy/clone over the data |
| 659 | flow->clone(flows[pred->_pre_order], max_reg); |
| 660 | } |
| 661 | |
| 662 | // Mark flow for block. Blocks can only be flowed over once, |
| 663 | // because after the first time they are guarded from entering |
| 664 | // this code again. |
| 665 | assert( flow->_b == pred, "have some prior flow" )do { if (!(flow->_b == pred)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/buildOopMap.cpp" , 665, "assert(" "flow->_b == pred" ") failed", "have some prior flow" ); ::breakpoint(); } } while (0); |
| 666 | flow->_b = NULL__null; |
| 667 | |
| 668 | // Now push flow forward |
| 669 | flows[b->_pre_order] = flow;// Mark flow for this block |
| 670 | flow->_b = b; |
| 671 | flow->compute_reach( C->regalloc(), max_reg, safehash ); |
| 672 | |
| 673 | // Now push children onto worklist |
| 674 | for( i=0; i<b->_num_succs; i++ ) |
| 675 | worklist.push(b->_succs[i]); |
| 676 | |
| 677 | } |
| 678 | } |