[wasm] Add support for import section.

src/wasm/wasm-module.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_WASM_MODULE_H_
 #define V8_WASM_MODULE_H_
 
 #include "src/wasm/wasm-opcodes.h"
 #include "src/wasm/wasm-result.h"
 
@@ skipping 12 matching lines @@
 const size_t kMaxFunctionSize = 128 * 1024;
 const size_t kMaxStringSize = 256;
 
 enum WasmSectionDeclCode {
   kDeclMemory = 0x00,
   kDeclSignatures = 0x01,
   kDeclFunctions = 0x02,
   kDeclGlobals = 0x03,
   kDeclDataSegments = 0x04,
   kDeclFunctionTable = 0x05,
-  kDeclWLL = 0x11,
   kDeclEnd = 0x06,
   kDeclStartFunction = 0x07,
+  kDeclImportTable = 0x08,
+  kDeclWLL = 0x11,
 };
 
-static const int kMaxModuleSectionCode = 6;
+static const int kMaxModuleSectionCode = 0x11;
 
 enum WasmFunctionDeclBit {
   kDeclFunctionName = 0x01,
   kDeclFunctionImport = 0x02,
   kDeclFunctionLocals = 0x04,
   kDeclFunctionExport = 0x08
 };
 
 // Constants for fixed-size elements within a module.
 static const size_t kDeclMemorySize = 3;
 static const size_t kDeclGlobalSize = 6;
 static const size_t kDeclDataSegmentSize = 13;
 
-// Static representation of a wasm function.
+// Static representation of a WASM function.
 struct WasmFunction {
   FunctionSig* sig;      // signature of the function.
   uint32_t func_index;   // index into the function table.
   uint16_t sig_index;    // index into the signature table.
   uint32_t name_offset;  // offset in the module bytes of the name, if any.
   uint32_t code_start_offset;    // offset in the module bytes of code start.
   uint32_t code_end_offset;      // offset in the module bytes of code end.
   uint16_t local_i32_count;      // number of i32 local variables.
   uint16_t local_i64_count;      // number of i64 local variables.
   uint16_t local_f32_count;      // number of f32 local variables.
   uint16_t local_f64_count;      // number of f64 local variables.
   bool exported;                 // true if this function is exported.
   bool external;  // true if this function is externally supplied.
 };
 
-struct ModuleEnv;  // forward declaration of decoder interface.
+// Static representation of an imported WASM function.
+struct WasmImport {
+  FunctionSig* sig;               // signature of the function.
+  uint16_t sig_index;             // index into the signature table.
+  uint32_t module_name_offset;    // offset in module bytes of the module name.
+  uint32_t function_name_offset;  // offset in module bytes of the import name.
+};
 
 // Static representation of a wasm global variable.
 struct WasmGlobal {
   uint32_t name_offset;  // offset in the module bytes of the name, if any.
   MachineType type;      // type of the global.
   uint32_t offset;       // offset from beginning of globals area.
   bool exported;         // true if this global is exported.
 };
 
 // Static representation of a wasm data segment.
@@ skipping 16 matching lines @@
   uint8_t max_mem_size_log2;  // maximum size of the memory (log base 2).
   bool mem_export;            // true if the memory is exported.
   bool mem_external;          // true if the memory is external.
   int start_function_index;   // start function, if any.
 
   std::vector<WasmGlobal>* globals;             // globals in this module.
   std::vector<FunctionSig*>* signatures;        // signatures in this module.
   std::vector<WasmFunction>* functions;         // functions in this module.
   std::vector<WasmDataSegment>* data_segments;  // data segments in this module.
   std::vector<uint16_t>* function_table;        // function table.
+  std::vector<WasmImport>* import_table;        // import table.
 
   WasmModule();
   ~WasmModule();
 
   // Get a pointer to a string stored in the module bytes representing a name.
   const char* GetName(uint32_t offset) const {
     if (offset == 0) return "<?>";  // no name.
     CHECK(BoundsCheck(offset, offset + 1));
     return reinterpret_cast<const char*>(module_start + offset);
   }
@@ skipping 12 matching lines @@
 // An instantiated WASM module, including memory, function table, etc.
 struct WasmModuleInstance {
   WasmModule* module;  // static representation of the module.
   // -- Heap allocated --------------------------------------------------------
   Handle<JSObject> js_object;            // JavaScript module object.
   Handle<Context> context;               // JavaScript native context.
   Handle<JSArrayBuffer> mem_buffer;      // Handle to array buffer of memory.
   Handle<JSArrayBuffer> globals_buffer;  // Handle to array buffer of globals.
   Handle<FixedArray> function_table;     // indirect function table.
   std::vector<Handle<Code>>* function_code;  // code objects for each function.
+  std::vector<Handle<Code>>* import_code;   // code objects for each import.
   // -- raw memory ------------------------------------------------------------
   byte* mem_start;  // start of linear memory.
   size_t mem_size;  // size of the linear memory.
   // -- raw globals -----------------------------------------------------------
   byte* globals_start;  // start of the globals area.
   size_t globals_size;  // size of the globals area.
 
   explicit WasmModuleInstance(WasmModule* m)
       : module(m),
         function_code(nullptr),
@@ skipping 16 matching lines @@
 
   bool IsValidGlobal(uint32_t index) {
     return module && index < module->globals->size();
   }
   bool IsValidFunction(uint32_t index) {
     return module && index < module->functions->size();
   }
   bool IsValidSignature(uint32_t index) {
     return module && index < module->signatures->size();
   }
+  bool IsValidImport(uint32_t index) {
+    return module && index < module->import_table->size();
+  }
   MachineType GetGlobalType(uint32_t index) {
     DCHECK(IsValidGlobal(index));
     return module->globals->at(index).type;
   }
   FunctionSig* GetFunctionSignature(uint32_t index) {
     DCHECK(IsValidFunction(index));
     return module->functions->at(index).sig;
   }
+  FunctionSig* GetImportSignature(uint32_t index) {
+    DCHECK(IsValidImport(index));
+    return module->import_table->at(index).sig;
+  }
   FunctionSig* GetSignature(uint32_t index) {
     DCHECK(IsValidSignature(index));
     return module->signatures->at(index);
   }
   size_t FunctionTableSize() {
     return module && module->function_table ? module->function_table->size()
                                             : 0;
   }
 
   Handle<Code> GetFunctionCode(uint32_t index);
+  Handle<Code> GetImportCode(uint32_t index);
   Handle<FixedArray> GetFunctionTable();
 
   compiler::CallDescriptor* GetWasmCallDescriptor(Zone* zone, FunctionSig* sig);
   static compiler::CallDescriptor* GetI32WasmCallDescriptor(
       Zone* zone, compiler::CallDescriptor* descriptor);
   compiler::CallDescriptor* GetCallDescriptor(Zone* zone, uint32_t index);
 };
 
 // A helper for printing out the names of functions.
 struct WasmFunctionName {
@@ skipping 17 matching lines @@
 
 // For testing. Decode, verify, and run the last exported function in the
 // given decoded module.
 int32_t CompileAndRunWasmModule(Isolate* isolate, WasmModule* module);
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_MODULE_H_