Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2013 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef V8_CRANKSHAFT_ARM64_LITHIUM_GAP_RESOLVER_ARM64_H_ |
| 6 | #define V8_CRANKSHAFT_ARM64_LITHIUM_GAP_RESOLVER_ARM64_H_ |
| 7 | |
| 8 | #include "src/crankshaft/arm64/delayed-masm-arm64.h" |
| 9 | #include "src/crankshaft/lithium.h" |
| 10 | |
| 11 | namespace v8 { |
| 12 | namespace internal { |
| 13 | |
| 14 | class LCodeGen; |
| 15 | class LGapResolver; |
| 16 | |
| 17 | class DelayedGapMasm : public DelayedMasm { |
| 18 | public: |
| 19 | DelayedGapMasm(LCodeGen* owner, MacroAssembler* masm) |
| 20 | : DelayedMasm(owner, masm, root) { |
| 21 | // We use the root register as an extra scratch register. |
| 22 | // The root register has two advantages: |
| 23 | // - It is not in crankshaft allocatable registers list, so it can't |
| 24 | // interfere with the allocatable registers. |
| 25 | // - We don't need to push it on the stack, as we can reload it with its |
| 26 | // value once we have finish. |
| 27 | } |
| 28 | void EndDelayedUse(); |
| 29 | }; |
| 30 | |
| 31 | |
| 32 | class LGapResolver BASE_EMBEDDED { |
| 33 | public: |
| 34 | explicit LGapResolver(LCodeGen* owner); |
| 35 | |
| 36 | // Resolve a set of parallel moves, emitting assembler instructions. |
| 37 | void Resolve(LParallelMove* parallel_move); |
| 38 | |
| 39 | private: |
| 40 | // Build the initial list of moves. |
| 41 | void BuildInitialMoveList(LParallelMove* parallel_move); |
| 42 | |
| 43 | // Perform the move at the moves_ index in question (possibly requiring |
| 44 | // other moves to satisfy dependencies). |
| 45 | void PerformMove(int index); |
| 46 | |
| 47 | // If a cycle is found in the series of moves, save the blocking value to |
| 48 | // a scratch register. The cycle must be found by hitting the root of the |
| 49 | // depth-first search. |
| 50 | void BreakCycle(int index); |
| 51 | |
| 52 | // After a cycle has been resolved, restore the value from the scratch |
| 53 | // register to its proper destination. |
| 54 | void RestoreValue(); |
| 55 | |
| 56 | // Emit a move and remove it from the move graph. |
| 57 | void EmitMove(int index); |
| 58 | |
| 59 | // Emit a move from one stack slot to another. |
| 60 | void EmitStackSlotMove(int index) { |
| 61 | masm_.StackSlotMove(moves_[index].source(), moves_[index].destination()); |
| 62 | } |
| 63 | |
| 64 | // Verify the move list before performing moves. |
| 65 | void Verify(); |
| 66 | |
| 67 | // Registers used to solve cycles. |
| 68 | const Register& SavedValueRegister() { |
Ben Murdoch | 61f157c | 2016-09-16 13:49:30 +0100 | [diff] [blame] | 69 | DCHECK(!RegisterConfiguration::Crankshaft()->IsAllocatableGeneralCode( |
| 70 | masm_.ScratchRegister().code())); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 71 | return masm_.ScratchRegister(); |
| 72 | } |
| 73 | // The scratch register is used to break cycles and to store constant. |
| 74 | // These two methods switch from one mode to the other. |
| 75 | void AcquireSavedValueRegister() { masm_.AcquireScratchRegister(); } |
| 76 | void ReleaseSavedValueRegister() { masm_.ReleaseScratchRegister(); } |
| 77 | const FPRegister& SavedFPValueRegister() { |
| 78 | // We use the Crankshaft floating-point scratch register to break a cycle |
| 79 | // involving double values as the MacroAssembler will not need it for the |
| 80 | // operations performed by the gap resolver. |
Ben Murdoch | 61f157c | 2016-09-16 13:49:30 +0100 | [diff] [blame] | 81 | DCHECK(!RegisterConfiguration::Crankshaft()->IsAllocatableGeneralCode( |
| 82 | crankshaft_fp_scratch.code())); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 83 | return crankshaft_fp_scratch; |
| 84 | } |
| 85 | |
| 86 | LCodeGen* cgen_; |
| 87 | DelayedGapMasm masm_; |
| 88 | |
| 89 | // List of moves not yet resolved. |
| 90 | ZoneList<LMoveOperands> moves_; |
| 91 | |
| 92 | int root_index_; |
| 93 | bool in_cycle_; |
| 94 | LOperand* saved_destination_; |
| 95 | }; |
| 96 | |
| 97 | } // namespace internal |
| 98 | } // namespace v8 |
| 99 | |
| 100 | #endif // V8_CRANKSHAFT_ARM64_LITHIUM_GAP_RESOLVER_ARM64_H_ |