[wasm] Allocate a single script per wasm module

src/wasm/wasm-debug.cc

 // Copyright 2016 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/assert-scope.h"
 #include "src/debug/debug.h"
 #include "src/factory.h"
 #include "src/isolate.h"
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-objects.h"
 
 using namespace v8::internal;
 using namespace v8::internal::wasm;
 
 namespace {
 
 enum {
   kWasmDebugInfoWasmObj,
   kWasmDebugInfoWasmBytesHash,
-  kWasmDebugInfoFunctionByteOffsets,
-  kWasmDebugInfoFunctionScripts,
   kWasmDebugInfoAsmJsOffsets,
   kWasmDebugInfoNumEntries
 };
 
-ByteArray *GetOrCreateFunctionOffsetTable(Handle<WasmDebugInfo> debug_info) {
-  Object *offset_table = debug_info->get(kWasmDebugInfoFunctionByteOffsets);
-  Isolate *isolate = debug_info->GetIsolate();
-  if (!offset_table->IsUndefined(isolate)) return ByteArray::cast(offset_table);
-
-  FunctionOffsetsResult function_offsets;
-  {
-    Handle<JSObject> wasm_instance(debug_info->wasm_instance(), isolate);
-    uint32_t num_imported_functions =
-        static_cast<uint32_t>(wasm::GetNumImportedFunctions(wasm_instance));
-    Handle<SeqOneByteString> wasm_bytes = wasm::GetWasmBytes(wasm_instance);
-    DisallowHeapAllocation no_gc;
-    const byte *bytes_start = wasm_bytes->GetChars();
-    const byte *bytes_end = bytes_start + wasm_bytes->length();
-    function_offsets = wasm::DecodeWasmFunctionOffsets(bytes_start, bytes_end,
-                                                       num_imported_functions);
-  }
-  DCHECK(function_offsets.ok());
-  size_t array_size = 2 * kIntSize * function_offsets.val.size();
-  CHECK_LE(array_size, static_cast<size_t>(kMaxInt));
-  ByteArray *arr =
-      *isolate->factory()->NewByteArray(static_cast<int>(array_size));
-  int idx = 0;
-  for (std::pair<int, int> p : function_offsets.val) {
-    arr->set_int(idx++, p.first);
-    arr->set_int(idx++, p.second);
-  }
-  DCHECK_EQ(arr->length(), idx * kIntSize);
-  debug_info->set(kWasmDebugInfoFunctionByteOffsets, arr);
-
-  return arr;
-}
-
-std::pair<int, int> GetFunctionOffsetAndLength(Handle<WasmDebugInfo> debug_info,
-                                               int func_index) {
-  ByteArray *arr = GetOrCreateFunctionOffsetTable(debug_info);
-  DCHECK(func_index >= 0 && func_index < arr->length() / kIntSize / 2);
-
-  int offset = arr->get_int(2 * func_index);
-  int length = arr->get_int(2 * func_index + 1);
-  // Assert that it's distinguishable from the "illegal function index" return.
-  DCHECK(offset > 0 && length > 0);
-  return {offset, length};
-}
-
-Vector<const uint8_t> GetFunctionBytes(Handle<WasmDebugInfo> debug_info,
-                                       int func_index) {
-  Handle<JSObject> wasm_instance(debug_info->wasm_instance());
-  Handle<SeqOneByteString> module_bytes = wasm::GetWasmBytes(wasm_instance);
-  std::pair<int, int> offset_and_length =
-      GetFunctionOffsetAndLength(debug_info, func_index);
-  return Vector<const uint8_t>(
-      module_bytes->GetChars() + offset_and_length.first,
-      offset_and_length.second);
-}
-
-FixedArray *GetOffsetTables(Handle<WasmDebugInfo> debug_info,
-                            Isolate *isolate) {
+// TODO(clemensh): Move asm.js offset tables to the compiled module.
+FixedArray *GetAsmJsOffsetTables(Handle<WasmDebugInfo> debug_info,
+                                 Isolate *isolate) {
   Object *offset_tables = debug_info->get(kWasmDebugInfoAsmJsOffsets);
   if (!offset_tables->IsUndefined(isolate)) {
     return FixedArray::cast(offset_tables);
   }
 
+  Handle<JSObject> wasm_instance(debug_info->wasm_instance(), isolate);
+  Handle<WasmCompiledModule> compiled_module(GetCompiledModule(*wasm_instance),
+                                             isolate);
+  DCHECK(compiled_module->has_asm_js_offset_tables());
+
   AsmJsOffsetsResult asm_offsets;
   {
-    Handle<JSObject> wasm_instance(debug_info->wasm_instance(), isolate);
-    Handle<WasmCompiledModule> compiled_module =
-        handle(GetCompiledModule(*wasm_instance), isolate);
-    DCHECK(compiled_module->has_asm_js_offset_tables());
     Handle<ByteArray> asm_offset_tables =
         compiled_module->asm_js_offset_tables();
-    uint32_t num_imported_functions =
-        static_cast<uint32_t>(wasm::GetNumImportedFunctions(wasm_instance));
     DisallowHeapAllocation no_gc;
     const byte *bytes_start = asm_offset_tables->GetDataStartAddress();
     const byte *bytes_end = bytes_start + asm_offset_tables->length();
-    asm_offsets = wasm::DecodeAsmJsOffsets(bytes_start, bytes_end,
-                                           num_imported_functions);
+    asm_offsets = wasm::DecodeAsmJsOffsets(bytes_start, bytes_end);
   }
   // Wasm bytes must be valid and must contain asm.js offset table.
   DCHECK(asm_offsets.ok());
   DCHECK_GE(static_cast<size_t>(kMaxInt), asm_offsets.val.size());
   int num_functions = static_cast<int>(asm_offsets.val.size());
-  DCHECK_EQ(wasm::GetNumberOfFunctions(handle(debug_info->wasm_instance())),
-            num_functions);
+  DCHECK_EQ(
+      wasm::GetNumberOfFunctions(handle(debug_info->wasm_instance())),
+      static_cast<int>(num_functions +
+                       compiled_module->module()->num_imported_functions));
   Handle<FixedArray> all_tables =
       isolate->factory()->NewFixedArray(num_functions);
   debug_info->set(kWasmDebugInfoAsmJsOffsets, *all_tables);
   for (int func = 0; func < num_functions; ++func) {
     std::vector<std::pair<int, int>> &func_asm_offsets = asm_offsets.val[func];
     if (func_asm_offsets.empty()) continue;
     size_t array_size = 2 * kIntSize * func_asm_offsets.size();
     CHECK_LE(array_size, static_cast<size_t>(kMaxInt));
     ByteArray *arr =
         *isolate->factory()->NewByteArray(static_cast<int>(array_size));
@@ skipping 26 matching lines @@
   }
   Handle<Object> hash_obj = factory->NewNumberFromInt(hash, TENURED);
   arr->set(kWasmDebugInfoWasmBytesHash, *hash_obj);
 
   return Handle<WasmDebugInfo>::cast(arr);
 }
 
 bool WasmDebugInfo::IsDebugInfo(Object *object) {
   if (!object->IsFixedArray()) return false;
   FixedArray *arr = FixedArray::cast(object);
-  Isolate *isolate = arr->GetIsolate();
   return arr->length() == kWasmDebugInfoNumEntries &&
          IsWasmInstance(arr->get(kWasmDebugInfoWasmObj)) &&
-         arr->get(kWasmDebugInfoWasmBytesHash)->IsNumber() &&
-         (arr->get(kWasmDebugInfoFunctionByteOffsets)->IsUndefined(isolate) ||
-          arr->get(kWasmDebugInfoFunctionByteOffsets)->IsByteArray()) &&
-         (arr->get(kWasmDebugInfoFunctionScripts)->IsUndefined(isolate) ||
-          arr->get(kWasmDebugInfoFunctionScripts)->IsFixedArray());
+         arr->get(kWasmDebugInfoWasmBytesHash)->IsNumber();
 }
 
 WasmDebugInfo *WasmDebugInfo::cast(Object *object) {
   DCHECK(IsDebugInfo(object));
   return reinterpret_cast<WasmDebugInfo *>(object);
 }
 
 JSObject *WasmDebugInfo::wasm_instance() {
   return JSObject::cast(get(kWasmDebugInfoWasmObj));
 }
 
-Script *WasmDebugInfo::GetFunctionScript(Handle<WasmDebugInfo> debug_info,
-                                         int func_index) {
-  Isolate *isolate = debug_info->GetIsolate();
-  Object *scripts_obj = debug_info->get(kWasmDebugInfoFunctionScripts);
-  Handle<FixedArray> scripts;
-  if (scripts_obj->IsUndefined(isolate)) {
-    Handle<JSObject> wasm_instance(debug_info->wasm_instance(), isolate);
-    int num_functions = wasm::GetNumberOfFunctions(wasm_instance);
-    scripts = isolate->factory()->NewFixedArray(num_functions, TENURED);
-    debug_info->set(kWasmDebugInfoFunctionScripts, *scripts);
-  } else {
-    scripts = handle(FixedArray::cast(scripts_obj), isolate);
-  }
-
-  DCHECK(func_index >= 0 && func_index < scripts->length());
-  Object *script_or_undef = scripts->get(func_index);
-  if (!script_or_undef->IsUndefined(isolate)) {
-    return Script::cast(script_or_undef);
-  }
-
-  Handle<Script> script =
-      isolate->factory()->NewScript(isolate->factory()->empty_string());
-  scripts->set(func_index, *script);
-
-  script->set_type(Script::TYPE_WASM);
-  script->set_wasm_instance(debug_info->wasm_instance());
-  script->set_wasm_function_index(func_index);
-
-  int hash = 0;
-  debug_info->get(kWasmDebugInfoWasmBytesHash)->ToInt32(&hash);
-  char buffer[32];
-  SNPrintF(ArrayVector(buffer), "wasm://%08x/%d", hash, func_index);
-  Handle<String> source_url =
-      isolate->factory()->NewStringFromAsciiChecked(buffer, TENURED);
-  script->set_source_url(*source_url);
-
-  int func_bytes_len =
-      GetFunctionOffsetAndLength(debug_info, func_index).second;
-  Handle<FixedArray> line_ends = isolate->factory()->NewFixedArray(1, TENURED);
-  line_ends->set(0, Smi::FromInt(func_bytes_len));
-  line_ends->set_map(isolate->heap()->fixed_cow_array_map());
-  script->set_line_ends(*line_ends);
-
-  // TODO(clemensh): Register with the debugger. Note that we cannot call into
-  // JS at this point since this function is called from within stack trace
-  // collection (which means we cannot call Debug::OnAfterCompile in its
-  // current form). See crbug.com/641065.
-  if (false) isolate->debug()->OnAfterCompile(script);
-
-  return *script;
-}
-
-Handle<String> WasmDebugInfo::DisassembleFunction(
-    Handle<WasmDebugInfo> debug_info, int func_index) {
-  std::ostringstream disassembly_os;
-
-  {
-    Vector<const uint8_t> bytes_vec = GetFunctionBytes(debug_info, func_index);
-    DisallowHeapAllocation no_gc;
-
-    AccountingAllocator allocator;
-    bool ok = PrintAst(
-        &allocator, FunctionBodyForTesting(bytes_vec.start(), bytes_vec.end()),
-        disassembly_os, nullptr);
-    DCHECK(ok);
-    USE(ok);
-  }
-
-  // Unfortunately, we have to copy the string here.
-  std::string code_str = disassembly_os.str();
-  CHECK_LE(code_str.length(), static_cast<size_t>(kMaxInt));
-  Factory *factory = debug_info->GetIsolate()->factory();
-  Vector<const char> code_vec(code_str.data(),
-                              static_cast<int>(code_str.length()));
-  return factory->NewStringFromAscii(code_vec).ToHandleChecked();
-}
-
-Handle<FixedArray> WasmDebugInfo::GetFunctionOffsetTable(
-    Handle<WasmDebugInfo> debug_info, int func_index) {
-  class NullBuf : public std::streambuf {};
-  NullBuf null_buf;
-  std::ostream null_stream(&null_buf);
-
-  std::vector<std::tuple<uint32_t, int, int>> offset_table_vec;
-
-  {
-    Vector<const uint8_t> bytes_vec = GetFunctionBytes(debug_info, func_index);
-    DisallowHeapAllocation no_gc;
-
-    AccountingAllocator allocator;
-    bool ok = PrintAst(
-        &allocator, FunctionBodyForTesting(bytes_vec.start(), bytes_vec.end()),
-        null_stream, &offset_table_vec);
-    DCHECK(ok);
-    USE(ok);
-  }
-
-  size_t arr_size = 3 * offset_table_vec.size();
-  CHECK_LE(arr_size, static_cast<size_t>(kMaxInt));
-  Factory *factory = debug_info->GetIsolate()->factory();
-  Handle<FixedArray> offset_table =
-      factory->NewFixedArray(static_cast<int>(arr_size), TENURED);
-
-  int idx = 0;
-  for (std::tuple<uint32_t, int, int> elem : offset_table_vec) {
-    offset_table->set(idx++, Smi::FromInt(std::get<0>(elem)));
-    offset_table->set(idx++, Smi::FromInt(std::get<1>(elem)));
-    offset_table->set(idx++, Smi::FromInt(std::get<2>(elem)));
-  }
-  DCHECK_EQ(idx, offset_table->length());
-
-  return offset_table;
-}
-
 int WasmDebugInfo::GetAsmJsSourcePosition(Handle<WasmDebugInfo> debug_info,
                                           int func_index, int byte_offset) {
   Isolate *isolate = debug_info->GetIsolate();
-  FixedArray *offset_tables = GetOffsetTables(debug_info, isolate);
+  Handle<JSObject> instance(debug_info->wasm_instance(), isolate);
+  FixedArray *offset_tables = GetAsmJsOffsetTables(debug_info, isolate);
 
+  WasmCompiledModule *compiled_module = wasm::GetCompiledModule(*instance);
+  int num_imported_functions =
+      compiled_module->module()->num_imported_functions;
+  DCHECK_LE(num_imported_functions, func_index);
+  func_index -= num_imported_functions;
   DCHECK_LT(func_index, offset_tables->length());
   ByteArray *offset_table = ByteArray::cast(offset_tables->get(func_index));
 
   // Binary search for the current byte offset.
   int left = 0;                                       // inclusive
   int right = offset_table->length() / kIntSize / 2;  // exclusive
   DCHECK_LT(left, right);
   while (right - left > 1) {
     int mid = left + (right - left) / 2;
     if (offset_table->get_int(2 * mid) <= byte_offset) {
       left = mid;
     } else {
       right = mid;
     }
   }
   // There should be an entry for each position that could show up on the stack
   // trace:
   DCHECK_EQ(byte_offset, offset_table->get_int(2 * left));
   return offset_table->get_int(2 * left + 1);
 }