1 // Copyright 2011 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_ARM_LITHIUM_GAP_RESOLVER_ARM_H_
6 #define V8_ARM_LITHIUM_GAP_RESOLVER_ARM_H_
7 
8 #include "src/v8.h"
9 
10 #include "src/lithium.h"
11 
12 namespace v8 {
13 namespace internal {
14 
15 class LCodeGen;
16 class LGapResolver;
17 
18 class LGapResolver FINAL BASE_EMBEDDED {
19  public:
20   explicit LGapResolver(LCodeGen* owner);
21 
22   // Resolve a set of parallel moves, emitting assembler instructions.
23   void Resolve(LParallelMove* parallel_move);
24 
25  private:
26   // Build the initial list of moves.
27   void BuildInitialMoveList(LParallelMove* parallel_move);
28 
29   // Perform the move at the moves_ index in question (possibly requiring
30   // other moves to satisfy dependencies).
31   void PerformMove(int index);
32 
33   // If a cycle is found in the series of moves, save the blocking value to
34   // a scratch register.  The cycle must be found by hitting the root of the
35   // depth-first search.
36   void BreakCycle(int index);
37 
38   // After a cycle has been resolved, restore the value from the scratch
39   // register to its proper destination.
40   void RestoreValue();
41 
42   // Emit a move and remove it from the move graph.
43   void EmitMove(int index);
44 
45   // Verify the move list before performing moves.
46   void Verify();
47 
48   LCodeGen* cgen_;
49 
50   // List of moves not yet resolved.
51   ZoneList<LMoveOperands> moves_;
52 
53   int root_index_;
54   bool in_cycle_;
55   LOperand* saved_destination_;
56 
57   // We use the root register as a scratch in a few places. When that happens,
58   // this flag is set to indicate that it needs to be restored.
59   bool need_to_restore_root_;
60 };
61 
62 } }  // namespace v8::internal
63 
64 #endif  // V8_ARM_LITHIUM_GAP_RESOLVER_ARM_H_
65