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| 1 // Copyright 2008 the V8 project authors. All rights reserved. | |
| 2 // Redistribution and use in source and binary forms, with or without | |
| 3 // modification, are permitted provided that the following conditions are | |
| 4 // met: | |
| 5 // | |
| 6 // * Redistributions of source code must retain the above copyright | |
| 7 // notice, this list of conditions and the following disclaimer. | |
| 8 // * Redistributions in binary form must reproduce the above | |
| 9 // copyright notice, this list of conditions and the following | |
| 10 // disclaimer in the documentation and/or other materials provided | |
| 11 // with the distribution. | |
| 12 // * Neither the name of Google Inc. nor the names of its | |
| 13 // contributors may be used to endorse or promote products derived | |
| 14 // from this software without specific prior written permission. | |
| 15 // | |
| 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 27 | |
| 28 #include "v8.h" | |
| 29 | |
| 30 #include "codegen-inl.h" | |
| 31 #include "register-allocator-inl.h" | |
| 32 | |
| 33 namespace v8 { namespace internal { | |
| 34 | |
| 35 // ------------------------------------------------------------------------- | |
| 36 // JumpTarget implementation. | |
| 37 | |
| 38 #define __ ACCESS_MASM(masm_) | |
| 39 | |
| 40 void JumpTarget::DoJump() { | |
| 41 ASSERT(cgen_ != NULL); | |
| 42 ASSERT(cgen_->has_valid_frame()); | |
| 43 // Live non-frame registers are not allowed at unconditional jumps | |
| 44 // because we have no way of invalidating the corresponding results | |
| 45 // which are still live in the C++ code. | |
| 46 ASSERT(cgen_->HasValidEntryRegisters()); | |
| 47 | |
| 48 if (is_bound()) { | |
| 49 // Backward jump. There is an expected frame to merge to. | |
| 50 ASSERT(direction_ == BIDIRECTIONAL); | |
| 51 cgen_->frame()->MergeTo(entry_frame_); | |
| 52 cgen_->DeleteFrame(); | |
| 53 __ jmp(&entry_label_); | |
| 54 } else { | |
| 55 // Forward jump. The current frame is added to the end of the list | |
| 56 // of frames reaching the target block and a jump to the merge code | |
| 57 // is emitted. | |
| 58 AddReachingFrame(cgen_->frame()); | |
| 59 RegisterFile empty; | |
| 60 cgen_->SetFrame(NULL, &empty); | |
| 61 __ jmp(&merge_labels_.last()); | |
| 62 } | |
| 63 | |
| 64 is_linked_ = !is_bound_; | |
| 65 } | |
| 66 | |
| 67 | |
| 68 void JumpTarget::DoBranch(Condition cc, Hint hint) { | |
| 69 ASSERT(cgen_ != NULL); | |
| 70 ASSERT(cgen_->has_valid_frame()); | |
| 71 | |
| 72 if (is_bound()) { | |
| 73 ASSERT(direction_ == BIDIRECTIONAL); | |
| 74 // Backward branch. We have an expected frame to merge to on the | |
| 75 // backward edge. | |
| 76 | |
| 77 // Swap the current frame for a copy (we do the swapping to get | |
| 78 // the off-frame registers off the fall through) to use for the | |
| 79 // branch. | |
| 80 VirtualFrame* fall_through_frame = cgen_->frame(); | |
| 81 VirtualFrame* branch_frame = new VirtualFrame(fall_through_frame); | |
| 82 RegisterFile non_frame_registers = RegisterAllocator::Reserved(); | |
| 83 cgen_->SetFrame(branch_frame, &non_frame_registers); | |
| 84 | |
| 85 // Check if we can avoid merge code. | |
| 86 cgen_->frame()->PrepareMergeTo(entry_frame_); | |
| 87 if (cgen_->frame()->Equals(entry_frame_)) { | |
| 88 // Branch right in to the block. | |
| 89 cgen_->DeleteFrame(); | |
| 90 __ j(cc, &entry_label_, hint); | |
| 91 cgen_->SetFrame(fall_through_frame, &non_frame_registers); | |
| 92 return; | |
| 93 } | |
| 94 | |
| 95 // Check if we can reuse existing merge code. | |
| 96 for (int i = 0; i < reaching_frames_.length(); i++) { | |
| 97 if (reaching_frames_[i] != NULL && | |
| 98 cgen_->frame()->Equals(reaching_frames_[i])) { | |
| 99 // Branch to the merge code. | |
| 100 cgen_->DeleteFrame(); | |
| 101 __ j(cc, &merge_labels_[i], hint); | |
| 102 cgen_->SetFrame(fall_through_frame, &non_frame_registers); | |
| 103 return; | |
| 104 } | |
| 105 } | |
| 106 | |
| 107 // To emit the merge code here, we negate the condition and branch | |
| 108 // around the merge code on the fall through path. | |
| 109 Label original_fall_through; | |
| 110 __ j(NegateCondition(cc), &original_fall_through, NegateHint(hint)); | |
| 111 cgen_->frame()->MergeTo(entry_frame_); | |
| 112 cgen_->DeleteFrame(); | |
| 113 __ jmp(&entry_label_); | |
| 114 cgen_->SetFrame(fall_through_frame, &non_frame_registers); | |
| 115 __ bind(&original_fall_through); | |
| 116 | |
| 117 } else { | |
| 118 // Forward branch. A copy of the current frame is added to the end | |
| 119 // of the list of frames reaching the target block and a branch to | |
| 120 // the merge code is emitted. | |
| 121 AddReachingFrame(new VirtualFrame(cgen_->frame())); | |
| 122 __ j(cc, &merge_labels_.last(), hint); | |
| 123 is_linked_ = true; | |
| 124 } | |
| 125 } | |
| 126 | |
| 127 | |
| 128 void JumpTarget::Call() { | |
| 129 // Call is used to push the address of the catch block on the stack as | |
| 130 // a return address when compiling try/catch and try/finally. We | |
| 131 // fully spill the frame before making the call. The expected frame | |
| 132 // at the label (which should be the only one) is the spilled current | |
| 133 // frame plus an in-memory return address. The "fall-through" frame | |
| 134 // at the return site is the spilled current frame. | |
| 135 ASSERT(cgen_ != NULL); | |
| 136 ASSERT(cgen_->has_valid_frame()); | |
| 137 // There are no non-frame references across the call. | |
| 138 ASSERT(cgen_->HasValidEntryRegisters()); | |
| 139 ASSERT(!is_linked()); | |
| 140 | |
| 141 cgen_->frame()->SpillAll(); | |
| 142 VirtualFrame* target_frame = new VirtualFrame(cgen_->frame()); | |
| 143 target_frame->Adjust(1); | |
| 144 AddReachingFrame(target_frame); | |
| 145 __ call(&merge_labels_.last()); | |
| 146 | |
| 147 is_linked_ = !is_bound_; | |
| 148 } | |
| 149 | |
| 150 | |
| 151 void JumpTarget::DoBind(int mergable_elements) { | |
| 152 ASSERT(cgen_ != NULL); | |
| 153 ASSERT(!is_bound()); | |
| 154 | |
| 155 // Live non-frame registers are not allowed at the start of a basic | |
| 156 // block. | |
| 157 ASSERT(!cgen_->has_valid_frame() || cgen_->HasValidEntryRegisters()); | |
| 158 | |
| 159 if (direction_ == FORWARD_ONLY) { | |
| 160 // A simple case: no forward jumps and no possible backward jumps. | |
| 161 if (!is_linked()) { | |
| 162 // The stack pointer can be floating above the top of the | |
| 163 // virtual frame before the bind. Afterward, it should not. | |
| 164 ASSERT(cgen_->has_valid_frame()); | |
| 165 VirtualFrame* frame = cgen_->frame(); | |
| 166 int difference = | |
| 167 frame->stack_pointer_ - (frame->elements_.length() - 1); | |
| 168 if (difference > 0) { | |
| 169 frame->stack_pointer_ -= difference; | |
| 170 __ add(Operand(esp), Immediate(difference * kPointerSize)); | |
| 171 } | |
| 172 | |
| 173 is_bound_ = true; | |
| 174 return; | |
| 175 } | |
| 176 | |
| 177 // Another simple case: no fall through, a single forward jump, | |
| 178 // and no possible backward jumps. | |
| 179 if (!cgen_->has_valid_frame() && reaching_frames_.length() == 1) { | |
| 180 // Pick up the only reaching frame, take ownership of it, and | |
| 181 // use it for the block about to be emitted. | |
| 182 VirtualFrame* frame = reaching_frames_[0]; | |
| 183 RegisterFile reserved = RegisterAllocator::Reserved(); | |
| 184 cgen_->SetFrame(frame, &reserved); | |
| 185 reaching_frames_[0] = NULL; | |
| 186 __ bind(&merge_labels_[0]); | |
| 187 | |
| 188 // The stack pointer can be floating above the top of the | |
| 189 // virtual frame before the bind. Afterward, it should not. | |
| 190 int difference = | |
| 191 frame->stack_pointer_ - (frame->elements_.length() - 1); | |
| 192 if (difference > 0) { | |
| 193 frame->stack_pointer_ -= difference; | |
| 194 __ add(Operand(esp), Immediate(difference * kPointerSize)); | |
| 195 } | |
| 196 | |
| 197 is_linked_ = false; | |
| 198 is_bound_ = true; | |
| 199 return; | |
| 200 } | |
| 201 } | |
| 202 | |
| 203 // If there is a current frame, record it as the fall-through. It | |
| 204 // is owned by the reaching frames for now. | |
| 205 bool had_fall_through = false; | |
| 206 if (cgen_->has_valid_frame()) { | |
| 207 had_fall_through = true; | |
| 208 AddReachingFrame(cgen_->frame()); | |
| 209 RegisterFile empty; | |
| 210 cgen_->SetFrame(NULL, &empty); | |
| 211 } | |
| 212 | |
| 213 // Compute the frame to use for entry to the block. | |
| 214 ComputeEntryFrame(mergable_elements); | |
| 215 | |
| 216 // Some moves required to merge to an expected frame require purely | |
| 217 // frame state changes, and do not require any code generation. | |
| 218 // Perform those first to increase the possibility of finding equal | |
| 219 // frames below. | |
| 220 for (int i = 0; i < reaching_frames_.length(); i++) { | |
| 221 if (reaching_frames_[i] != NULL) { | |
| 222 reaching_frames_[i]->PrepareMergeTo(entry_frame_); | |
| 223 } | |
| 224 } | |
| 225 | |
| 226 if (is_linked()) { | |
| 227 // There were forward jumps. Handle merging the reaching frames | |
| 228 // to the entry frame. | |
| 229 | |
| 230 // Loop over the (non-null) reaching frames and process any that | |
| 231 // need merge code. Iterate backwards through the list to handle | |
| 232 // the fall-through frame first. Set frames that will be | |
| 233 // processed after 'i' to NULL if we want to avoid processing | |
| 234 // them. | |
| 235 for (int i = reaching_frames_.length() - 1; i >= 0; i--) { | |
| 236 VirtualFrame* frame = reaching_frames_[i]; | |
| 237 | |
| 238 if (frame != NULL) { | |
| 239 // Does the frame (probably) need merge code? | |
| 240 if (!frame->Equals(entry_frame_)) { | |
| 241 // We could have a valid frame as the fall through to the | |
| 242 // binding site or as the fall through from a previous merge | |
| 243 // code block. Jump around the code we are about to | |
| 244 // generate. | |
| 245 if (cgen_->has_valid_frame()) { | |
| 246 cgen_->DeleteFrame(); | |
| 247 __ jmp(&entry_label_); | |
| 248 } | |
| 249 // Pick up the frame for this block. Assume ownership if | |
| 250 // there cannot be backward jumps. | |
| 251 RegisterFile reserved = RegisterAllocator::Reserved(); | |
| 252 if (direction_ == BIDIRECTIONAL) { | |
| 253 cgen_->SetFrame(new VirtualFrame(frame), &reserved); | |
| 254 } else { | |
| 255 cgen_->SetFrame(frame, &reserved); | |
| 256 reaching_frames_[i] = NULL; | |
| 257 } | |
| 258 __ bind(&merge_labels_[i]); | |
| 259 | |
| 260 // Loop over the remaining (non-null) reaching frames, | |
| 261 // looking for any that can share merge code with this one. | |
| 262 for (int j = 0; j < i; j++) { | |
| 263 VirtualFrame* other = reaching_frames_[j]; | |
| 264 if (other != NULL && other->Equals(cgen_->frame())) { | |
| 265 // Set the reaching frame element to null to avoid | |
| 266 // processing it later, and then bind its entry label. | |
| 267 delete other; | |
| 268 reaching_frames_[j] = NULL; | |
| 269 __ bind(&merge_labels_[j]); | |
| 270 } | |
| 271 } | |
| 272 | |
| 273 // Emit the merge code. | |
| 274 cgen_->frame()->MergeTo(entry_frame_); | |
| 275 } else if (i == reaching_frames_.length() - 1 && had_fall_through) { | |
| 276 // If this is the fall through frame, and it didn't need | |
| 277 // merge code, we need to pick up the frame so we can jump | |
| 278 // around subsequent merge blocks if necessary. | |
| 279 RegisterFile reserved = RegisterAllocator::Reserved(); | |
| 280 cgen_->SetFrame(frame, &reserved); | |
| 281 reaching_frames_[i] = NULL; | |
| 282 } | |
| 283 } | |
| 284 } | |
| 285 | |
| 286 // The code generator may not have a current frame if there was no | |
| 287 // fall through and none of the reaching frames needed merging. | |
| 288 // In that case, clone the entry frame as the current frame. | |
| 289 if (!cgen_->has_valid_frame()) { | |
| 290 RegisterFile reserved_registers = RegisterAllocator::Reserved(); | |
| 291 cgen_->SetFrame(new VirtualFrame(entry_frame_), &reserved_registers); | |
| 292 } | |
| 293 | |
| 294 // There is certainly a current frame equal to the entry frame. | |
| 295 // Bind the entry frame label. | |
| 296 __ bind(&entry_label_); | |
| 297 | |
| 298 // There may be unprocessed reaching frames that did not need | |
| 299 // merge code. They will have unbound merge labels. Bind their | |
| 300 // merge labels to be the same as the entry label and deallocate | |
| 301 // them. | |
| 302 for (int i = 0; i < reaching_frames_.length(); i++) { | |
| 303 if (!merge_labels_[i].is_bound()) { | |
| 304 delete reaching_frames_[i]; | |
| 305 reaching_frames_[i] = NULL; | |
| 306 __ bind(&merge_labels_[i]); | |
| 307 } | |
| 308 } | |
| 309 | |
| 310 // There are non-NULL reaching frames with bound labels for each | |
| 311 // merge block, but only on backward targets. | |
| 312 } else { | |
| 313 // There were no forward jumps. There must be a current frame and | |
| 314 // this must be a bidirectional target. | |
| 315 ASSERT(reaching_frames_.length() == 1); | |
| 316 ASSERT(reaching_frames_[0] != NULL); | |
| 317 ASSERT(direction_ == BIDIRECTIONAL); | |
| 318 | |
| 319 // Use a copy of the reaching frame so the original can be saved | |
| 320 // for possible reuse as a backward merge block. | |
| 321 RegisterFile reserved = RegisterAllocator::Reserved(); | |
| 322 cgen_->SetFrame(new VirtualFrame(reaching_frames_[0]), &reserved); | |
| 323 __ bind(&merge_labels_[0]); | |
| 324 cgen_->frame()->MergeTo(entry_frame_); | |
| 325 __ bind(&entry_label_); | |
| 326 } | |
| 327 | |
| 328 is_linked_ = false; | |
| 329 is_bound_ = true; | |
| 330 } | |
| 331 | |
| 332 #undef __ | |
| 333 | |
| 334 | |
| 335 } } // namespace v8::internal | |
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Chromium Code Reviews
Issue 92068:
Move backend specific files to separate directories. (Closed)
