1 // Copyright 2015 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_WASM_WASM_MODULE_BUILDER_H_
6 #define V8_WASM_WASM_MODULE_BUILDER_H_
7
8 #include "src/signature.h"
9 #include "src/zone/zone-containers.h"
10
11 #include "src/wasm/leb-helper.h"
12 #include "src/wasm/wasm-macro-gen.h"
13 #include "src/wasm/wasm-module.h"
14 #include "src/wasm/wasm-opcodes.h"
15 #include "src/wasm/wasm-result.h"
16
17 namespace v8 {
18 namespace internal {
19 namespace wasm {
20
21 class ZoneBuffer : public ZoneObject {
22 public:
23 static const uint32_t kInitialSize = 4096;
24 explicit ZoneBuffer(Zone* zone, size_t initial = kInitialSize)
zone_(zone)25 : zone_(zone), buffer_(reinterpret_cast<byte*>(zone->New(initial))) {
26 pos_ = buffer_;
27 end_ = buffer_ + initial;
28 }
29
write_u8(uint8_t x)30 void write_u8(uint8_t x) {
31 EnsureSpace(1);
32 *(pos_++) = x;
33 }
34
write_u16(uint16_t x)35 void write_u16(uint16_t x) {
36 EnsureSpace(2);
37 WriteLittleEndianValue<uint16_t>(pos_, x);
38 pos_ += 2;
39 }
40
write_u32(uint32_t x)41 void write_u32(uint32_t x) {
42 EnsureSpace(4);
43 WriteLittleEndianValue<uint32_t>(pos_, x);
44 pos_ += 4;
45 }
46
write_u32v(uint32_t val)47 void write_u32v(uint32_t val) {
48 EnsureSpace(kMaxVarInt32Size);
49 LEBHelper::write_u32v(&pos_, val);
50 }
51
write_i32v(int32_t val)52 void write_i32v(int32_t val) {
53 EnsureSpace(kMaxVarInt32Size);
54 LEBHelper::write_i32v(&pos_, val);
55 }
56
write_size(size_t val)57 void write_size(size_t val) {
58 EnsureSpace(kMaxVarInt32Size);
59 DCHECK_EQ(val, static_cast<uint32_t>(val));
60 LEBHelper::write_u32v(&pos_, static_cast<uint32_t>(val));
61 }
62
write(const byte * data,size_t size)63 void write(const byte* data, size_t size) {
64 EnsureSpace(size);
65 memcpy(pos_, data, size);
66 pos_ += size;
67 }
68
reserve_u32v()69 size_t reserve_u32v() {
70 size_t off = offset();
71 EnsureSpace(kMaxVarInt32Size);
72 pos_ += kMaxVarInt32Size;
73 return off;
74 }
75
76 // Patch a (padded) u32v at the given offset to be the given value.
patch_u32v(size_t offset,uint32_t val)77 void patch_u32v(size_t offset, uint32_t val) {
78 byte* ptr = buffer_ + offset;
79 for (size_t pos = 0; pos != kPaddedVarInt32Size; ++pos) {
80 uint32_t next = val >> 7;
81 byte out = static_cast<byte>(val & 0x7f);
82 if (pos != kPaddedVarInt32Size - 1) {
83 *(ptr++) = 0x80 | out;
84 val = next;
85 } else {
86 *(ptr++) = out;
87 }
88 }
89 }
90
offset()91 size_t offset() const { return static_cast<size_t>(pos_ - buffer_); }
size()92 size_t size() const { return static_cast<size_t>(pos_ - buffer_); }
begin()93 const byte* begin() const { return buffer_; }
end()94 const byte* end() const { return pos_; }
95
EnsureSpace(size_t size)96 void EnsureSpace(size_t size) {
97 if ((pos_ + size) > end_) {
98 size_t new_size = 4096 + size + (end_ - buffer_) * 3;
99 byte* new_buffer = reinterpret_cast<byte*>(zone_->New(new_size));
100 memcpy(new_buffer, buffer_, (pos_ - buffer_));
101 pos_ = new_buffer + (pos_ - buffer_);
102 buffer_ = new_buffer;
103 end_ = new_buffer + new_size;
104 }
105 DCHECK(pos_ + size <= end_);
106 }
107
pos_ptr()108 byte** pos_ptr() { return &pos_; }
109
110 private:
111 Zone* zone_;
112 byte* buffer_;
113 byte* pos_;
114 byte* end_;
115 };
116
117 class WasmModuleBuilder;
118
119 class V8_EXPORT_PRIVATE WasmFunctionBuilder : public ZoneObject {
120 public:
121 // Building methods.
122 void SetSignature(FunctionSig* sig);
123 uint32_t AddLocal(LocalType type);
124 void EmitVarInt(uint32_t val);
125 void EmitCode(const byte* code, uint32_t code_size);
126 void Emit(WasmOpcode opcode);
127 void EmitGetLocal(uint32_t index);
128 void EmitSetLocal(uint32_t index);
129 void EmitTeeLocal(uint32_t index);
130 void EmitI32Const(int32_t val);
131 void EmitWithU8(WasmOpcode opcode, const byte immediate);
132 void EmitWithU8U8(WasmOpcode opcode, const byte imm1, const byte imm2);
133 void EmitWithVarInt(WasmOpcode opcode, uint32_t immediate);
134 void EmitDirectCallIndex(uint32_t index);
135 void Export();
136 void ExportAs(Vector<const char> name);
137 void SetName(Vector<const char> name);
138 void AddAsmWasmOffset(int asm_position);
139
140 void WriteSignature(ZoneBuffer& buffer) const;
141 void WriteExport(ZoneBuffer& buffer) const;
142 void WriteBody(ZoneBuffer& buffer) const;
143 void WriteAsmWasmOffsetTable(ZoneBuffer& buffer) const;
144
exported()145 bool exported() { return exported_; }
func_index()146 uint32_t func_index() { return func_index_; }
147 FunctionSig* signature();
148
149 private:
150 explicit WasmFunctionBuilder(WasmModuleBuilder* builder);
151 friend class WasmModuleBuilder;
152 friend class WasmTemporary;
153
154 struct DirectCallIndex {
155 size_t offset;
156 uint32_t direct_index;
157 };
158
159 WasmModuleBuilder* builder_;
160 LocalDeclEncoder locals_;
161 uint32_t signature_index_;
162 bool exported_;
163 uint32_t func_index_;
164 ZoneVector<uint8_t> body_;
165 ZoneVector<char> name_;
166 ZoneVector<char> exported_name_;
167 ZoneVector<uint32_t> i32_temps_;
168 ZoneVector<uint32_t> i64_temps_;
169 ZoneVector<uint32_t> f32_temps_;
170 ZoneVector<uint32_t> f64_temps_;
171 ZoneVector<DirectCallIndex> direct_calls_;
172
173 // Delta-encoded mapping from wasm bytes to asm.js source positions.
174 ZoneBuffer asm_offsets_;
175 uint32_t last_asm_byte_offset_ = 0;
176 uint32_t last_asm_source_position_ = 0;
177 };
178
179 class WasmTemporary {
180 public:
WasmTemporary(WasmFunctionBuilder * builder,LocalType type)181 WasmTemporary(WasmFunctionBuilder* builder, LocalType type) {
182 switch (type) {
183 case kAstI32:
184 temporary_ = &builder->i32_temps_;
185 break;
186 case kAstI64:
187 temporary_ = &builder->i64_temps_;
188 break;
189 case kAstF32:
190 temporary_ = &builder->f32_temps_;
191 break;
192 case kAstF64:
193 temporary_ = &builder->f64_temps_;
194 break;
195 default:
196 UNREACHABLE();
197 temporary_ = nullptr;
198 }
199 if (temporary_->size() == 0) {
200 // Allocate a new temporary.
201 index_ = builder->AddLocal(type);
202 } else {
203 // Reuse a previous temporary.
204 index_ = temporary_->back();
205 temporary_->pop_back();
206 }
207 }
~WasmTemporary()208 ~WasmTemporary() {
209 temporary_->push_back(index_); // return the temporary to the list.
210 }
index()211 uint32_t index() { return index_; }
212
213 private:
214 ZoneVector<uint32_t>* temporary_;
215 uint32_t index_;
216 };
217
218 class V8_EXPORT_PRIVATE WasmModuleBuilder : public ZoneObject {
219 public:
220 explicit WasmModuleBuilder(Zone* zone);
221
222 // Building methods.
223 uint32_t AddImport(const char* name, int name_length, FunctionSig* sig);
SetImportName(uint32_t index,const char * name,int name_length)224 void SetImportName(uint32_t index, const char* name, int name_length) {
225 imports_[index].name = name;
226 imports_[index].name_length = name_length;
227 }
228 WasmFunctionBuilder* AddFunction(FunctionSig* sig = nullptr);
229 uint32_t AddGlobal(LocalType type, bool exported, bool mutability = true,
230 const WasmInitExpr& init = WasmInitExpr());
231 void AddDataSegment(const byte* data, uint32_t size, uint32_t dest);
232 uint32_t AddSignature(FunctionSig* sig);
233 void AddIndirectFunction(uint32_t index);
234 void MarkStartFunction(WasmFunctionBuilder* builder);
235
236 // Writing methods.
237 void WriteTo(ZoneBuffer& buffer) const;
238 void WriteAsmJsOffsetTable(ZoneBuffer& buffer) const;
239
240 // TODO(titzer): use SignatureMap from signature-map.h here.
241 // This signature map is zone-allocated, but the other is heap allocated.
242 struct CompareFunctionSigs {
243 bool operator()(FunctionSig* a, FunctionSig* b) const;
244 };
245 typedef ZoneMap<FunctionSig*, uint32_t, CompareFunctionSigs> SignatureMap;
246
zone()247 Zone* zone() { return zone_; }
248
GetSignature(uint32_t index)249 FunctionSig* GetSignature(uint32_t index) { return signatures_[index]; }
250
251 private:
252 struct WasmFunctionImport {
253 uint32_t sig_index;
254 const char* name;
255 int name_length;
256 };
257
258 struct WasmGlobal {
259 LocalType type;
260 bool exported;
261 bool mutability;
262 WasmInitExpr init;
263 };
264
265 struct WasmDataSegment {
266 ZoneVector<byte> data;
267 uint32_t dest;
268 };
269
270 friend class WasmFunctionBuilder;
271 Zone* zone_;
272 ZoneVector<FunctionSig*> signatures_;
273 ZoneVector<WasmFunctionImport> imports_;
274 ZoneVector<WasmFunctionBuilder*> functions_;
275 ZoneVector<WasmDataSegment> data_segments_;
276 ZoneVector<uint32_t> indirect_functions_;
277 ZoneVector<WasmGlobal> globals_;
278 SignatureMap signature_map_;
279 int start_function_index_;
280 };
281
signature()282 inline FunctionSig* WasmFunctionBuilder::signature() {
283 return builder_->signatures_[signature_index_];
284 }
285
286 } // namespace wasm
287 } // namespace internal
288 } // namespace v8
289
290 #endif // V8_WASM_WASM_MODULE_BUILDER_H_
291