[wasm] Add support for multiple indirect function tables

src/wasm/module-decoder.cc

 // 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.
 
 #include "src/wasm/module-decoder.h"
 
 #include "src/base/functional.h"
 #include "src/base/platform/platform.h"
 #include "src/macro-assembler.h"
 #include "src/objects.h"
@@ skipping 239 matching lines @@
                   static_cast<int>(pc_ - start_));
             module->data_segments.push_back({0,        // dest_addr
                                              0,        // source_offset
                                              0,        // source_size
                                              false});  // init
             WasmDataSegment* segment = &module->data_segments.back();
             DecodeDataSegmentInModule(module, segment);
           }
           break;
         }
-        case WasmSection::Code::FunctionTablePad: {
-          if (!FLAG_wasm_jit_prototype) {
-            error("FunctionTablePad section without jiting enabled");
-          }
-          // An indirect function table requires functions first.
-          module->indirect_table_size = consume_u32v("indirect entry count");
-          if (module->indirect_table_size > 0 &&
-              module->indirect_table_size < module->function_table.size()) {
-            error("more predefined indirect entries than table can hold");
-          }
-          break;
-        }
         case WasmSection::Code::FunctionTable: {
           // An indirect function table requires functions first.
           CheckForFunctions(module, section);
-          uint32_t function_table_count = consume_u32v("function table count");
-          module->function_table.reserve(SafeReserve(function_table_count));
+          // Assume only one table for now.
+          uint32_t table_count = 1;

[Mircea Trofin, 2016/07/26 03:37:27]

static const uint32_t kSupportedTableCount = 1

[ddchen, 2016/07/26 05:44:44]

Done.

+          module->function_tables.reserve(SafeReserve(table_count));
           // Decode function table.
-          for (uint32_t i = 0; i < function_table_count; ++i) {
+          for (uint32_t i = 0; i < table_count; ++i) {
             if (failed()) break;
             TRACE("DecodeFunctionTable[%d] module+%d\n", i,
                   static_cast<int>(pc_ - start_));
-            uint16_t index = consume_u32v();
-            if (index >= module->functions.size()) {
-              error(pc_ - 2, "invalid function index");
-              break;
-            }
-            module->function_table.push_back(index);
-          }
-          if (module->indirect_table_size > 0 &&
-              module->indirect_table_size < module->function_table.size()) {
-            error("more predefined indirect entries than table can hold");
+            module->function_tables.push_back({0, 0, std::vector<uint16_t>()});
+            DecodeFunctionTableInModule(module,
+                                        &module->function_tables.back());

[Mircea Trofin, 2016/07/26 03:37:26]

should it be module->function_tables[i], for consistency? 

[ddchen, 2016/07/26 05:44:44]

Done.

           }
           break;
         }
         case WasmSection::Code::StartFunction: {
           // Declares a start function for a module.
           CheckForFunctions(module, section);
           if (module->start_function_index >= 0) {
             error("start function already declared");
             break;
           }
@@ skipping 211 matching lines @@
         WasmModule::kPageSize * (module ? module->min_mem_pages
                                         : WasmModule::kMaxMemPages);
     if (!IsWithinLimit(memory_limit, segment->dest_addr,
                        segment->source_size)) {
       error(start, "segment out of bounds of memory");
     }
 
     consume_bytes(segment->source_size);
   }
 
+  // Decodes a single function table inside a module starting at {pc_}.
+  void DecodeFunctionTableInModule(WasmModule* module, WasmTable* table) {
+    table->size = consume_u32v("function table entry count");
+    table->max_size = FLAG_wasm_jit_prototype ? consume_u32v() : table->size;
+
+    if ((!FLAG_wasm_jit_prototype && table->max_size != table->size) ||
+        (FLAG_wasm_jit_prototype && table->max_size < table->size)) {
+      error("invalid table maximum size");
+    }
+
+    for (uint32_t i = 0; i < table->size; i++) {

[Mircea Trofin, 2016/07/26 03:37:26]

++i

[ddchen, 2016/07/26 05:44:44]

Done.

+      uint16_t index = consume_u32v();
+      if (index >= module->functions.size()) {
+        error(pc_ - 2, "invalid function index");

[Mircea Trofin, 2016/07/26 03:37:26]

what's "2"? (sizeof(uint16_t) ?)

[ddchen, 2016/07/26 05:44:44]

Done.

+        break;
+      }
+      table->values.push_back(index);
+    }
+  }
+
   // Calculate individual global offsets and total size of globals table.
   void CalculateGlobalsOffsets(WasmModule* module) {
     uint32_t offset = 0;
     if (module->globals.size() == 0) {
       module->globals_size = 0;
       return;
     }
     for (WasmGlobal& global : module->globals) {
       byte size =
           WasmOpcodes::MemSize(WasmOpcodes::MachineTypeFor(global.type));
@@ skipping 275 matching lines @@
     decoder.consume_bytes(size);
   }
   if (decoder.more()) decoder.error("unexpected additional bytes");
 
   return decoder.toResult(std::move(table));
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8