1 // Copyright 2014 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_COMPILER_CODE_GENERATOR_H_
6 #define V8_COMPILER_CODE_GENERATOR_H_
7 
8 #include "src/compiler/gap-resolver.h"
9 #include "src/compiler/instruction.h"
10 #include "src/compiler/unwinding-info-writer.h"
11 #include "src/deoptimizer.h"
12 #include "src/macro-assembler.h"
13 #include "src/safepoint-table.h"
14 #include "src/source-position-table.h"
15 
16 namespace v8 {
17 namespace internal {
18 
19 class CompilationInfo;
20 
21 namespace compiler {
22 
23 // Forward declarations.
24 class DeoptimizationExit;
25 class FrameAccessState;
26 class Linkage;
27 class OutOfLineCode;
28 
29 struct BranchInfo {
30   FlagsCondition condition;
31   Label* true_label;
32   Label* false_label;
33   bool fallthru;
34 };
35 
36 
37 class InstructionOperandIterator {
38  public:
InstructionOperandIterator(Instruction * instr,size_t pos)39   InstructionOperandIterator(Instruction* instr, size_t pos)
40       : instr_(instr), pos_(pos) {}
41 
instruction()42   Instruction* instruction() const { return instr_; }
Advance()43   InstructionOperand* Advance() { return instr_->InputAt(pos_++); }
44 
45  private:
46   Instruction* instr_;
47   size_t pos_;
48 };
49 
50 
51 // Generates native code for a sequence of instructions.
52 class CodeGenerator final : public GapResolver::Assembler {
53  public:
54   explicit CodeGenerator(Frame* frame, Linkage* linkage,
55                          InstructionSequence* code, CompilationInfo* info);
56 
57   // Generate native code.
58   Handle<Code> GenerateCode();
59 
code()60   InstructionSequence* code() const { return code_; }
frame_access_state()61   FrameAccessState* frame_access_state() const { return frame_access_state_; }
frame()62   const Frame* frame() const { return frame_access_state_->frame(); }
63   Isolate* isolate() const;
linkage()64   Linkage* linkage() const { return linkage_; }
65 
GetLabel(RpoNumber rpo)66   Label* GetLabel(RpoNumber rpo) { return &labels_[rpo.ToSize()]; }
67 
68  private:
masm()69   MacroAssembler* masm() { return &masm_; }
resolver()70   GapResolver* resolver() { return &resolver_; }
safepoints()71   SafepointTableBuilder* safepoints() { return &safepoints_; }
zone()72   Zone* zone() const { return code()->zone(); }
info()73   CompilationInfo* info() const { return info_; }
74 
75   // Create the FrameAccessState object. The Frame is immutable from here on.
76   void CreateFrameAccessState(Frame* frame);
77 
78   // Architecture - specific frame finalization.
79   void FinishFrame(Frame* frame);
80 
81   // Checks if {block} will appear directly after {current_block_} when
82   // assembling code, in which case, a fall-through can be used.
83   bool IsNextInAssemblyOrder(RpoNumber block) const;
84 
85   // Record a safepoint with the given pointer map.
86   void RecordSafepoint(ReferenceMap* references, Safepoint::Kind kind,
87                        int arguments, Safepoint::DeoptMode deopt_mode);
88 
89   // Check if a heap object can be materialized by loading from a heap root,
90   // which is cheaper on some platforms than materializing the actual heap
91   // object constant.
92   bool IsMaterializableFromRoot(Handle<HeapObject> object,
93                                 Heap::RootListIndex* index_return);
94 
95   enum CodeGenResult { kSuccess, kTooManyDeoptimizationBailouts };
96 
97   // Assemble instructions for the specified block.
98   CodeGenResult AssembleBlock(const InstructionBlock* block);
99 
100   // Assemble code for the specified instruction.
101   CodeGenResult AssembleInstruction(Instruction* instr,
102                                     const InstructionBlock* block);
103   void AssembleSourcePosition(Instruction* instr);
104   void AssembleGaps(Instruction* instr);
105 
106   // Returns true if a instruction is a tail call that needs to adjust the stack
107   // pointer before execution. The stack slot index to the empty slot above the
108   // adjusted stack pointer is returned in |slot|.
109   bool GetSlotAboveSPBeforeTailCall(Instruction* instr, int* slot);
110 
111   // ===========================================================================
112   // ============= Architecture-specific code generation methods. ==============
113   // ===========================================================================
114 
115   CodeGenResult AssembleArchInstruction(Instruction* instr);
116   void AssembleArchJump(RpoNumber target);
117   void AssembleArchBranch(Instruction* instr, BranchInfo* branch);
118   void AssembleArchBoolean(Instruction* instr, FlagsCondition condition);
119   void AssembleArchLookupSwitch(Instruction* instr);
120   void AssembleArchTableSwitch(Instruction* instr);
121 
122   CodeGenResult AssembleDeoptimizerCall(int deoptimization_id,
123                                         Deoptimizer::BailoutType bailout_type,
124                                         SourcePosition pos);
125 
126   // Generates an architecture-specific, descriptor-specific prologue
127   // to set up a stack frame.
128   void AssembleConstructFrame();
129 
130   // Generates an architecture-specific, descriptor-specific return sequence
131   // to tear down a stack frame.
132   void AssembleReturn(InstructionOperand* pop);
133 
134   void AssembleDeconstructFrame();
135 
136   // Generates code to manipulate the stack in preparation for a tail call.
137   void AssemblePrepareTailCall();
138 
139   // Generates code to pop current frame if it is an arguments adaptor frame.
140   void AssemblePopArgumentsAdaptorFrame(Register args_reg, Register scratch1,
141                                         Register scratch2, Register scratch3);
142 
143   enum PushTypeFlag {
144     kImmediatePush = 0x1,
145     kScalarPush = 0x2,
146     kFloat32Push = 0x4,
147     kFloat64Push = 0x8,
148     kFloatPush = kFloat32Push | kFloat64Push
149   };
150 
151   typedef base::Flags<PushTypeFlag> PushTypeFlags;
152 
153   static bool IsValidPush(InstructionOperand source, PushTypeFlags push_type);
154 
155   // Generate a list moves from an instruction that are candidates to be turned
156   // into push instructions on platforms that support them. In general, the list
157   // of push candidates are moves to a set of contiguous destination
158   // InstructionOperand locations on the stack that don't clobber values that
159   // are needed for resolve the gap or use values generated by the gap,
160   // i.e. moves that can be hoisted together before the actual gap and assembled
161   // together.
162   static void GetPushCompatibleMoves(Instruction* instr,
163                                      PushTypeFlags push_type,
164                                      ZoneVector<MoveOperands*>* pushes);
165 
166   // Called before a tail call |instr|'s gap moves are assembled and allows
167   // gap-specific pre-processing, e.g. adjustment of the sp for tail calls that
168   // need it before gap moves or conversion of certain gap moves into pushes.
169   void AssembleTailCallBeforeGap(Instruction* instr,
170                                  int first_unused_stack_slot);
171   // Called after a tail call |instr|'s gap moves are assembled and allows
172   // gap-specific post-processing, e.g. adjustment of the sp for tail calls that
173   // need it after gap moves.
174   void AssembleTailCallAfterGap(Instruction* instr,
175                                 int first_unused_stack_slot);
176 
177   // ===========================================================================
178   // ============== Architecture-specific gap resolver methods. ================
179   // ===========================================================================
180 
181   // Interface used by the gap resolver to emit moves and swaps.
182   void AssembleMove(InstructionOperand* source,
183                     InstructionOperand* destination) final;
184   void AssembleSwap(InstructionOperand* source,
185                     InstructionOperand* destination) final;
186 
187   // ===========================================================================
188   // =================== Jump table construction methods. ======================
189   // ===========================================================================
190 
191   class JumpTable;
192   // Adds a jump table that is emitted after the actual code.  Returns label
193   // pointing to the beginning of the table.  {targets} is assumed to be static
194   // or zone allocated.
195   Label* AddJumpTable(Label** targets, size_t target_count);
196   // Emits a jump table.
197   void AssembleJumpTable(Label** targets, size_t target_count);
198 
199   // ===========================================================================
200   // ================== Deoptimization table construction. =====================
201   // ===========================================================================
202 
203   void RecordCallPosition(Instruction* instr);
204   void PopulateDeoptimizationData(Handle<Code> code);
205   int DefineDeoptimizationLiteral(Handle<Object> literal);
206   DeoptimizationEntry const& GetDeoptimizationEntry(Instruction* instr,
207                                                     size_t frame_state_offset);
208   DeoptimizeReason GetDeoptimizationReason(int deoptimization_id) const;
209   int BuildTranslation(Instruction* instr, int pc_offset,
210                        size_t frame_state_offset,
211                        OutputFrameStateCombine state_combine);
212   void BuildTranslationForFrameStateDescriptor(
213       FrameStateDescriptor* descriptor, InstructionOperandIterator* iter,
214       Translation* translation, OutputFrameStateCombine state_combine);
215   void TranslateStateValueDescriptor(StateValueDescriptor* desc,
216                                      Translation* translation,
217                                      InstructionOperandIterator* iter);
218   void TranslateFrameStateDescriptorOperands(FrameStateDescriptor* desc,
219                                              InstructionOperandIterator* iter,
220                                              OutputFrameStateCombine combine,
221                                              Translation* translation);
222   void AddTranslationForOperand(Translation* translation, Instruction* instr,
223                                 InstructionOperand* op, MachineType type);
224   void EnsureSpaceForLazyDeopt();
225   void MarkLazyDeoptSite();
226 
227   DeoptimizationExit* AddDeoptimizationExit(Instruction* instr,
228                                             size_t frame_state_offset);
229 
230   // ===========================================================================
231 
232   class DeoptimizationState final : public ZoneObject {
233    public:
DeoptimizationState(BailoutId bailout_id,int translation_id,int pc_offset,DeoptimizeReason reason)234     DeoptimizationState(BailoutId bailout_id, int translation_id, int pc_offset,
235                         DeoptimizeReason reason)
236         : bailout_id_(bailout_id),
237           translation_id_(translation_id),
238           pc_offset_(pc_offset),
239           reason_(reason) {}
240 
bailout_id()241     BailoutId bailout_id() const { return bailout_id_; }
translation_id()242     int translation_id() const { return translation_id_; }
pc_offset()243     int pc_offset() const { return pc_offset_; }
reason()244     DeoptimizeReason reason() const { return reason_; }
245 
246    private:
247     BailoutId bailout_id_;
248     int translation_id_;
249     int pc_offset_;
250     DeoptimizeReason reason_;
251   };
252 
253   struct HandlerInfo {
254     Label* handler;
255     int pc_offset;
256   };
257 
258   friend class OutOfLineCode;
259 
260   FrameAccessState* frame_access_state_;
261   Linkage* const linkage_;
262   InstructionSequence* const code_;
263   UnwindingInfoWriter unwinding_info_writer_;
264   CompilationInfo* const info_;
265   Label* const labels_;
266   Label return_label_;
267   RpoNumber current_block_;
268   SourcePosition current_source_position_;
269   MacroAssembler masm_;
270   GapResolver resolver_;
271   SafepointTableBuilder safepoints_;
272   ZoneVector<HandlerInfo> handlers_;
273   ZoneDeque<DeoptimizationExit*> deoptimization_exits_;
274   ZoneDeque<DeoptimizationState*> deoptimization_states_;
275   ZoneDeque<Handle<Object>> deoptimization_literals_;
276   size_t inlined_function_count_;
277   TranslationBuffer translations_;
278   int last_lazy_deopt_pc_;
279   JumpTable* jump_tables_;
280   OutOfLineCode* ools_;
281   int osr_pc_offset_;
282   SourcePositionTableBuilder source_position_table_builder_;
283 };
284 
285 }  // namespace compiler
286 }  // namespace internal
287 }  // namespace v8
288 
289 #endif  // V8_COMPILER_CODE_GENERATOR_H
290