[wasm] Master CL for Binary 0xC changes.

src/wasm/encoder.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/signature.h"
 
 #include "src/handles.h"
 #include "src/v8.h"
 #include "src/zone-containers.h"
 
@@ skipping 12 matching lines @@
     if (FLAG_trace_wasm_encoder) PrintF(__VA_ARGS__); \
   } while (false)
 #else
 #define TRACE(...)
 #endif
 
 namespace v8 {
 namespace internal {
 namespace wasm {
 
-// Emit a section name and the size as a padded varint that can be patched
+// Emit a section code and the size as a padded varint that can be patched
 // later.
-size_t EmitSection(WasmSection::Code code, ZoneBuffer& buffer) {
-  // Emit the section name.
-  const char* name = WasmSection::getName(code);
-  TRACE("emit section: %s\n", name);
-  size_t length = WasmSection::getNameLength(code);
-  buffer.write_size(length);  // Section name string size.
-  buffer.write(reinterpret_cast<const byte*>(name), length);
+size_t EmitSection(WasmSectionCode code, ZoneBuffer& buffer) {
+  // Emit the section code.
+  buffer.write_u8(code);
 
   // Emit a placeholder for the length.
   return buffer.reserve_u32v();
 }
 
 // Patch the size of a section after it's finished.
 void FixupSection(ZoneBuffer& buffer, size_t start) {
   buffer.patch_u32v(start, static_cast<uint32_t>(buffer.offset() - start -
                                                  kPaddedVarInt32Size));
 }
 
 WasmFunctionBuilder::WasmFunctionBuilder(WasmModuleBuilder* builder)
     : builder_(builder),
       locals_(builder->zone()),
       signature_index_(0),
       exported_(0),
+      func_index_(static_cast<uint32_t>(builder->imports_.size() +
+                                        builder->functions_.size())),
       body_(builder->zone()),
       name_(builder->zone()),
       i32_temps_(builder->zone()),
       i64_temps_(builder->zone()),
       f32_temps_(builder->zone()),
       f64_temps_(builder->zone()) {}
 
 void WasmFunctionBuilder::EmitVarInt(uint32_t val) {
   byte buffer[8];
   byte* ptr = buffer;
@@ skipping 15 matching lines @@
 }
 
 void WasmFunctionBuilder::EmitGetLocal(uint32_t local_index) {
   EmitWithVarInt(kExprGetLocal, local_index);
 }
 
 void WasmFunctionBuilder::EmitSetLocal(uint32_t local_index) {
   EmitWithVarInt(kExprSetLocal, local_index);
 }
 
+void WasmFunctionBuilder::EmitTeeLocal(uint32_t local_index) {
+  EmitWithVarInt(kExprTeeLocal, local_index);
+}
+
 void WasmFunctionBuilder::EmitCode(const byte* code, uint32_t code_size) {
   for (size_t i = 0; i < code_size; ++i) {
     body_.push_back(code[i]);
   }
 }
 
 void WasmFunctionBuilder::Emit(WasmOpcode opcode) {
   body_.push_back(static_cast<byte>(opcode));
 }
 
@@ skipping 33 matching lines @@
     for (int i = 0; i < name_length; ++i) {
       name_.push_back(*(name + i));
     }
   }
 }
 
 void WasmFunctionBuilder::WriteSignature(ZoneBuffer& buffer) const {
   buffer.write_u32v(signature_index_);
 }
 
-void WasmFunctionBuilder::WriteExport(ZoneBuffer& buffer,
-                                      uint32_t func_index) const {
+void WasmFunctionBuilder::WriteExport(ZoneBuffer& buffer) const {
   if (exported_) {
-    buffer.write_u32v(func_index);
     buffer.write_size(name_.size());
     if (name_.size() > 0) {
       buffer.write(reinterpret_cast<const byte*>(&name_[0]), name_.size());
     }
+    buffer.write_u8(kExternalFunction);
+    buffer.write_u32v(func_index_);
   }
 }
 
 void WasmFunctionBuilder::WriteBody(ZoneBuffer& buffer) const {
   size_t locals_size = locals_.Size();
   buffer.write_size(locals_size + body_.size());
   buffer.EnsureSpace(locals_size);
   byte** ptr = buffer.pos_ptr();
   locals_.Emit(*ptr);
   (*ptr) += locals_size;  // UGLY: manual bump of position pointer
   if (body_.size() > 0) {
     buffer.write(&body_[0], body_.size());
   }
 }
 
 WasmDataSegmentEncoder::WasmDataSegmentEncoder(Zone* zone, const byte* data,
                                                uint32_t size, uint32_t dest)
     : data_(zone), dest_(dest) {
   for (size_t i = 0; i < size; ++i) {
     data_.push_back(data[i]);
   }
 }
 
 void WasmDataSegmentEncoder::Write(ZoneBuffer& buffer) const {
+  buffer.write_u8(0);  // linear memory zero
+  buffer.write_u8(kExprI32Const);
   buffer.write_u32v(dest_);
+  buffer.write_u8(kExprEnd);
   buffer.write_u32v(static_cast<uint32_t>(data_.size()));
   buffer.write(&data_[0], data_.size());
 }
 
 WasmModuleBuilder::WasmModuleBuilder(Zone* zone)
     : zone_(zone),
       signatures_(zone),
       imports_(zone),
       functions_(zone),
       data_segments_(zone),
       indirect_functions_(zone),
       globals_(zone),
       signature_map_(zone),
       start_function_index_(-1) {}
 
-uint32_t WasmModuleBuilder::AddFunction() {
+WasmFunctionBuilder* WasmModuleBuilder::AddFunction(FunctionSig* sig) {
   functions_.push_back(new (zone_) WasmFunctionBuilder(this));
-  return static_cast<uint32_t>(functions_.size() - 1);
-}
-
-WasmFunctionBuilder* WasmModuleBuilder::FunctionAt(size_t index) {
-  if (functions_.size() > index) {
-    return functions_.at(index);
-  } else {
-    return nullptr;
-  }
+  if (sig) functions_.back()->SetSignature(sig);

[ahaas, 2016/09/16 11:42:18]

Could you add a comment about what it means if sig == nullptr?

[titzer, 2016/09/16 12:23:20]

Done.

+  return functions_.back();
 }
 
 void WasmModuleBuilder::AddDataSegment(WasmDataSegmentEncoder* data) {
   data_segments_.push_back(data);
 }
 
 bool WasmModuleBuilder::CompareFunctionSigs::operator()(FunctionSig* a,
                                                         FunctionSig* b) const {
   if (a->return_count() < b->return_count()) return true;
   if (a->return_count() > b->return_count()) return false;
@@ skipping 21 matching lines @@
     return index;
   }
 }
 
 void WasmModuleBuilder::AddIndirectFunction(uint32_t index) {
   indirect_functions_.push_back(index);
 }
 
 uint32_t WasmModuleBuilder::AddImport(const char* name, int name_length,
                                       FunctionSig* sig) {
+  DCHECK_EQ(0, functions_.size());  // imports must be added before functions!
   imports_.push_back({AddSignature(sig), name, name_length});
   return static_cast<uint32_t>(imports_.size() - 1);
 }
 
-void WasmModuleBuilder::MarkStartFunction(uint32_t index) {
-  start_function_index_ = index;
+void WasmModuleBuilder::MarkStartFunction(WasmFunctionBuilder* function) {
+  start_function_index_ = function->func_index();
 }
 
-uint32_t WasmModuleBuilder::AddGlobal(LocalType type, bool exported) {
-  globals_.push_back(std::make_pair(type, exported));
+uint32_t WasmModuleBuilder::AddGlobal(LocalType type, bool exported,
+                                      bool mutability) {
+  globals_.push_back(std::make_tuple(type, exported, mutability));
   return static_cast<uint32_t>(globals_.size() - 1);
 }
 
 void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
   uint32_t exports = 0;
+  bool names = false;

[ahaas, 2016/09/16 11:42:18]

I think it would be better if this variable were declared just before it is
used. Maybe it should also be called {has_names}.

[titzer, 2016/09/16 12:23:20]

Done.

 
   // == Emit magic =============================================================
   TRACE("emit magic\n");
   buffer.write_u32(kWasmMagic);
   buffer.write_u32(kWasmVersion);
 
   // == Emit signatures ========================================================
   if (signatures_.size() > 0) {
-    size_t start = EmitSection(WasmSection::Code::Signatures, buffer);
+    size_t start = EmitSection(kTypeSectionCode, buffer);
     buffer.write_size(signatures_.size());
 
     for (FunctionSig* sig : signatures_) {
       buffer.write_u8(kWasmFunctionTypeForm);
       buffer.write_size(sig->parameter_count());
       for (size_t j = 0; j < sig->parameter_count(); j++) {
         buffer.write_u8(WasmOpcodes::LocalTypeCodeFor(sig->GetParam(j)));
       }
       buffer.write_size(sig->return_count());
       for (size_t j = 0; j < sig->return_count(); j++) {
         buffer.write_u8(WasmOpcodes::LocalTypeCodeFor(sig->GetReturn(j)));
       }
     }
     FixupSection(buffer, start);
   }
 
-  // == Emit globals ===========================================================
-  if (globals_.size() > 0) {
-    size_t start = EmitSection(WasmSection::Code::Globals, buffer);
-    buffer.write_size(globals_.size());
-
-    for (auto global : globals_) {
-      buffer.write_u32v(0);  // Length of the global name.
-      buffer.write_u8(WasmOpcodes::LocalTypeCodeFor(global.first));
-      buffer.write_u8(global.second);
-    }
-    FixupSection(buffer, start);
-  }
-
   // == Emit imports ===========================================================
   if (imports_.size() > 0) {
-    size_t start = EmitSection(WasmSection::Code::ImportTable, buffer);
+    size_t start = EmitSection(kImportSectionCode, buffer);
     buffer.write_size(imports_.size());
     for (auto import : imports_) {
+      buffer.write_u32v(import.name_length);  // module name length

[ahaas, 2016/09/16 11:42:18]

Are these comments really consistent with the code?

[titzer, 2016/09/16 12:23:20]

Done.

+      buffer.write(reinterpret_cast<const byte*>(import.name),  // module name
+                   import.name_length);
+      buffer.write_u32v(0);  // import name length
+      buffer.write_u8(kExternalFunction);
       buffer.write_u32v(import.sig_index);
-      buffer.write_u32v(import.name_length);
-      buffer.write(reinterpret_cast<const byte*>(import.name),
-                   import.name_length);
-      buffer.write_u32v(0);
     }
     FixupSection(buffer, start);
   }
 
   // == Emit function signatures ===============================================
   if (functions_.size() > 0) {
-    size_t start = EmitSection(WasmSection::Code::FunctionSignatures, buffer);
+    size_t start = EmitSection(kFunctionSectionCode, buffer);
     buffer.write_size(functions_.size());
     for (auto function : functions_) {
       function->WriteSignature(buffer);
       if (function->exported()) exports++;
+      if (function->name_.size() > 0) names = true;
     }
     FixupSection(buffer, start);
   }
 
   // == emit function table ====================================================
   if (indirect_functions_.size() > 0) {
-    size_t start = EmitSection(WasmSection::Code::FunctionTable, buffer);
+    size_t start = EmitSection(kTableSectionCode, buffer);
+    buffer.write_u8(1);  // table count
+    buffer.write_u8(kWasmAnyFunctionTypeForm);
+    buffer.write_u8(kResizableMaximumFlag);
     buffer.write_size(indirect_functions_.size());
-
-    for (auto index : indirect_functions_) {
-      buffer.write_u32v(index);
-    }
+    buffer.write_size(indirect_functions_.size());
     FixupSection(buffer, start);
   }
 
   // == emit memory declaration ================================================
   {
-    size_t start = EmitSection(WasmSection::Code::Memory, buffer);
+    size_t start = EmitSection(kMemorySectionCode, buffer);
+    buffer.write_u8(1);  // memory count
+    buffer.write_u32v(kResizableMaximumFlag);
     buffer.write_u32v(16);  // min memory size
     buffer.write_u32v(16);  // max memory size
-    buffer.write_u8(0);     // memory export
-    static_assert(kDeclMemorySize == 3, "memory size must match emit above");
+    FixupSection(buffer, start);
+  }
+
+  // == Emit globals ===========================================================
+  if (globals_.size() > 0) {
+    size_t start = EmitSection(kGlobalSectionCode, buffer);
+    buffer.write_size(globals_.size());
+
+    for (auto global : globals_) {

[ahaas, 2016/09/16 11:42:18]

I think auto makes code harder to read. Would it be possible not to use auto?

[titzer, 2016/09/16 12:23:20]

All the loops here are doing that. It's a matter of how much context there is to
determine the type. In these cases, we are iterating over vectors that contain
functions, globals, etc.

Sadly in this case, it's a tuple. And C++ tuples are such a hassle...

[ahaas, 2016/09/16 13:32:51]

Could you add a comment which says that global is a tuple?

+      buffer.write_u8(WasmOpcodes::LocalTypeCodeFor(std::get<0>(global)));

[ahaas, 2016/09/16 11:42:18]

Define a constant instead of using 0 here.

[titzer, 2016/09/16 12:23:20]

Done.

+      buffer.write_u8(std::get<2>(global));

[ahaas, 2016/09/16 11:42:18]

same here

[titzer, 2016/09/16 12:23:20]

Done.

+      switch (std::get<0>(global)) {

[ahaas, 2016/09/16 11:42:18]

same here.

[titzer, 2016/09/16 12:23:20]

Done.

+        case kAstI32: {
+          static const byte code[] = {WASM_I32V_1(0)};
+          buffer.write(code, sizeof(code));
+          break;
+        }
+        case kAstF32: {
+          static const byte code[] = {WASM_F32(0)};
+          buffer.write(code, sizeof(code));
+          break;
+        }
+        case kAstI64: {
+          static const byte code[] = {WASM_I64V_1(0)};
+          buffer.write(code, sizeof(code));
+          break;
+        }
+        case kAstF64: {
+          static const byte code[] = {WASM_F64(0.0)};
+          buffer.write(code, sizeof(code));
+          break;
+        }
+        default:
+          UNREACHABLE();
+      }
+      buffer.write_u8(kExprEnd);
+    }
     FixupSection(buffer, start);
   }
 
   // == emit exports ===========================================================
   if (exports > 0) {
-    size_t start = EmitSection(WasmSection::Code::ExportTable, buffer);
+    size_t start = EmitSection(kExportSectionCode, buffer);
     buffer.write_u32v(exports);
-    uint32_t index = 0;
-    for (auto function : functions_) {
-      function->WriteExport(buffer, index++);
-    }
+    for (auto function : functions_) function->WriteExport(buffer);
     FixupSection(buffer, start);
   }
 
   // == emit start function index ==============================================
   if (start_function_index_ >= 0) {
-    size_t start = EmitSection(WasmSection::Code::StartFunction, buffer);
+    size_t start = EmitSection(kStartSectionCode, buffer);
     buffer.write_u32v(start_function_index_);
     FixupSection(buffer, start);
   }
 
+  // == emit function table elements ===========================================
+  if (indirect_functions_.size() > 0) {
+    size_t start = EmitSection(kElementSectionCode, buffer);
+    buffer.write_u8(1);              // count of entries
+    buffer.write_u8(0);              // table index
+    buffer.write_u8(kExprI32Const);  // offset
+    buffer.write_u32v(0);
+    buffer.write_u8(kExprEnd);
+    buffer.write_size(indirect_functions_.size());  // element count
+
+    for (auto index : indirect_functions_) {
+      buffer.write_u32v(index);
+    }
+
+    FixupSection(buffer, start);
+  }
+
   // == emit code ==============================================================
   if (functions_.size() > 0) {
-    size_t start = EmitSection(WasmSection::Code::FunctionBodies, buffer);
+    size_t start = EmitSection(kCodeSectionCode, buffer);
     buffer.write_size(functions_.size());
     for (auto function : functions_) {
       function->WriteBody(buffer);
     }
     FixupSection(buffer, start);
   }
 
   // == emit data segments =====================================================
   if (data_segments_.size() > 0) {
-    size_t start = EmitSection(WasmSection::Code::DataSegments, buffer);
+    size_t start = EmitSection(kDataSectionCode, buffer);
     buffer.write_size(data_segments_.size());
 
     for (auto segment : data_segments_) {
       segment->Write(buffer);
     }
     FixupSection(buffer, start);
   }
+
+  // == Emit names =============================================================
+  if (names) {
+    // Emit the section code.
+    buffer.write_u8(kUnknownSectionCode);
+    // Emit the section string.
+    buffer.write_size(4);
+    buffer.write(reinterpret_cast<const byte*>("name"), 4);
+    // Emit a placeholder for the length.
+    size_t start = buffer.reserve_u32v();
+    // Emit the names.
+    buffer.write_size(functions_.size());
+    for (auto function : functions_) {
+      buffer.write_size(function->name_.size());
+      if (function->name_.size() > 0) {
+        buffer.write(reinterpret_cast<const byte*>(&function->name_[0]),
+                     function->name_.size());
+      }
+      buffer.write_u8(0);
+    }
+    FixupSection(buffer, start);
+  }
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8