Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame^] | 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 "jump-target-inl.h" |
| 32 | #include "register-allocator-inl.h" |
| 33 | |
| 34 | namespace v8 { |
| 35 | namespace internal { |
| 36 | |
| 37 | // ------------------------------------------------------------------------- |
| 38 | // JumpTarget implementation. |
| 39 | |
| 40 | #define __ ACCESS_MASM(cgen()->masm()) |
| 41 | |
| 42 | void JumpTarget::DoJump() { |
| 43 | ASSERT(cgen()->has_valid_frame()); |
| 44 | // Live non-frame registers are not allowed at unconditional jumps |
| 45 | // because we have no way of invalidating the corresponding results |
| 46 | // which are still live in the C++ code. |
| 47 | ASSERT(cgen()->HasValidEntryRegisters()); |
| 48 | |
| 49 | if (is_bound()) { |
| 50 | // Backward jump. There already a frame expectation at the target. |
| 51 | ASSERT(direction_ == BIDIRECTIONAL); |
| 52 | cgen()->frame()->MergeTo(entry_frame_); |
| 53 | cgen()->DeleteFrame(); |
| 54 | } else { |
| 55 | // Use the current frame as the expected one at the target if necessary. |
| 56 | if (entry_frame_ == NULL) { |
| 57 | entry_frame_ = cgen()->frame(); |
| 58 | RegisterFile empty; |
| 59 | cgen()->SetFrame(NULL, &empty); |
| 60 | } else { |
| 61 | cgen()->frame()->MergeTo(entry_frame_); |
| 62 | cgen()->DeleteFrame(); |
| 63 | } |
| 64 | |
| 65 | // The predicate is_linked() should be made true. Its implementation |
| 66 | // detects the presence of a frame pointer in the reaching_frames_ list. |
| 67 | if (!is_linked()) { |
| 68 | reaching_frames_.Add(NULL); |
| 69 | ASSERT(is_linked()); |
| 70 | } |
| 71 | } |
| 72 | __ jmp(&entry_label_); |
| 73 | } |
| 74 | |
| 75 | |
| 76 | void JumpTarget::DoBranch(Condition cc, Hint ignored) { |
| 77 | ASSERT(cgen()->has_valid_frame()); |
| 78 | |
| 79 | if (is_bound()) { |
| 80 | ASSERT(direction_ == BIDIRECTIONAL); |
| 81 | // Backward branch. We have an expected frame to merge to on the |
| 82 | // backward edge. |
| 83 | cgen()->frame()->MergeTo(entry_frame_); |
| 84 | } else { |
| 85 | // Clone the current frame to use as the expected one at the target if |
| 86 | // necessary. |
| 87 | if (entry_frame_ == NULL) { |
| 88 | entry_frame_ = new VirtualFrame(cgen()->frame()); |
| 89 | } |
| 90 | // The predicate is_linked() should be made true. Its implementation |
| 91 | // detects the presence of a frame pointer in the reaching_frames_ list. |
| 92 | if (!is_linked()) { |
| 93 | reaching_frames_.Add(NULL); |
| 94 | ASSERT(is_linked()); |
| 95 | } |
| 96 | } |
| 97 | __ b(cc, &entry_label_); |
| 98 | } |
| 99 | |
| 100 | |
| 101 | void JumpTarget::Call() { |
| 102 | // Call is used to push the address of the catch block on the stack as |
| 103 | // a return address when compiling try/catch and try/finally. We |
| 104 | // fully spill the frame before making the call. The expected frame |
| 105 | // at the label (which should be the only one) is the spilled current |
| 106 | // frame plus an in-memory return address. The "fall-through" frame |
| 107 | // at the return site is the spilled current frame. |
| 108 | ASSERT(cgen()->has_valid_frame()); |
| 109 | // There are no non-frame references across the call. |
| 110 | ASSERT(cgen()->HasValidEntryRegisters()); |
| 111 | ASSERT(!is_linked()); |
| 112 | |
| 113 | // Calls are always 'forward' so we use a copy of the current frame (plus |
| 114 | // one for a return address) as the expected frame. |
| 115 | ASSERT(entry_frame_ == NULL); |
| 116 | VirtualFrame* target_frame = new VirtualFrame(cgen()->frame()); |
| 117 | target_frame->Adjust(1); |
| 118 | entry_frame_ = target_frame; |
| 119 | |
| 120 | // The predicate is_linked() should now be made true. Its implementation |
| 121 | // detects the presence of a frame pointer in the reaching_frames_ list. |
| 122 | reaching_frames_.Add(NULL); |
| 123 | ASSERT(is_linked()); |
| 124 | |
| 125 | __ bl(&entry_label_); |
| 126 | } |
| 127 | |
| 128 | |
| 129 | void JumpTarget::DoBind() { |
| 130 | ASSERT(!is_bound()); |
| 131 | |
| 132 | // Live non-frame registers are not allowed at the start of a basic |
| 133 | // block. |
| 134 | ASSERT(!cgen()->has_valid_frame() || cgen()->HasValidEntryRegisters()); |
| 135 | |
| 136 | if (cgen()->has_valid_frame()) { |
| 137 | // If there is a current frame we can use it on the fall through. |
| 138 | if (entry_frame_ == NULL) { |
| 139 | entry_frame_ = new VirtualFrame(cgen()->frame()); |
| 140 | } else { |
| 141 | ASSERT(cgen()->frame()->Equals(entry_frame_)); |
| 142 | } |
| 143 | } else { |
| 144 | // If there is no current frame we must have an entry frame which we can |
| 145 | // copy. |
| 146 | ASSERT(entry_frame_ != NULL); |
| 147 | RegisterFile empty; |
| 148 | cgen()->SetFrame(new VirtualFrame(entry_frame_), &empty); |
| 149 | } |
| 150 | |
| 151 | // The predicate is_linked() should be made false. Its implementation |
| 152 | // detects the presence (or absence) of frame pointers in the |
| 153 | // reaching_frames_ list. If we inserted a bogus frame to make |
| 154 | // is_linked() true, remove it now. |
| 155 | if (is_linked()) { |
| 156 | reaching_frames_.Clear(); |
| 157 | } |
| 158 | |
| 159 | __ bind(&entry_label_); |
| 160 | } |
| 161 | |
| 162 | |
| 163 | void BreakTarget::Jump() { |
| 164 | // On ARM we do not currently emit merge code for jumps, so we need to do |
| 165 | // it explicitly here. The only merging necessary is to drop extra |
| 166 | // statement state from the stack. |
| 167 | ASSERT(cgen()->has_valid_frame()); |
| 168 | int count = cgen()->frame()->height() - expected_height_; |
| 169 | cgen()->frame()->Drop(count); |
| 170 | DoJump(); |
| 171 | } |
| 172 | |
| 173 | |
| 174 | void BreakTarget::Jump(Result* arg) { |
| 175 | // On ARM we do not currently emit merge code for jumps, so we need to do |
| 176 | // it explicitly here. The only merging necessary is to drop extra |
| 177 | // statement state from the stack. |
| 178 | ASSERT(cgen()->has_valid_frame()); |
| 179 | int count = cgen()->frame()->height() - expected_height_; |
| 180 | cgen()->frame()->Drop(count); |
| 181 | cgen()->frame()->Push(arg); |
| 182 | DoJump(); |
| 183 | } |
| 184 | |
| 185 | |
| 186 | void BreakTarget::Bind() { |
| 187 | #ifdef DEBUG |
| 188 | // All the forward-reaching frames should have been adjusted at the |
| 189 | // jumps to this target. |
| 190 | for (int i = 0; i < reaching_frames_.length(); i++) { |
| 191 | ASSERT(reaching_frames_[i] == NULL || |
| 192 | reaching_frames_[i]->height() == expected_height_); |
| 193 | } |
| 194 | #endif |
| 195 | // Drop leftover statement state from the frame before merging, even |
| 196 | // on the fall through. This is so we can bind the return target |
| 197 | // with state on the frame. |
| 198 | if (cgen()->has_valid_frame()) { |
| 199 | int count = cgen()->frame()->height() - expected_height_; |
| 200 | // On ARM we do not currently emit merge code at binding sites, so we need |
| 201 | // to do it explicitly here. The only merging necessary is to drop extra |
| 202 | // statement state from the stack. |
| 203 | cgen()->frame()->Drop(count); |
| 204 | } |
| 205 | |
| 206 | DoBind(); |
| 207 | } |
| 208 | |
| 209 | |
| 210 | void BreakTarget::Bind(Result* arg) { |
| 211 | #ifdef DEBUG |
| 212 | // All the forward-reaching frames should have been adjusted at the |
| 213 | // jumps to this target. |
| 214 | for (int i = 0; i < reaching_frames_.length(); i++) { |
| 215 | ASSERT(reaching_frames_[i] == NULL || |
| 216 | reaching_frames_[i]->height() == expected_height_ + 1); |
| 217 | } |
| 218 | #endif |
| 219 | // Drop leftover statement state from the frame before merging, even |
| 220 | // on the fall through. This is so we can bind the return target |
| 221 | // with state on the frame. |
| 222 | if (cgen()->has_valid_frame()) { |
| 223 | int count = cgen()->frame()->height() - expected_height_; |
| 224 | // On ARM we do not currently emit merge code at binding sites, so we need |
| 225 | // to do it explicitly here. The only merging necessary is to drop extra |
| 226 | // statement state from the stack. |
| 227 | cgen()->frame()->ForgetElements(count); |
| 228 | cgen()->frame()->Push(arg); |
| 229 | } |
| 230 | DoBind(); |
| 231 | *arg = cgen()->frame()->Pop(); |
| 232 | } |
| 233 | |
| 234 | |
| 235 | #undef __ |
| 236 | |
| 237 | |
| 238 | } } // namespace v8::internal |