[wasm] asm.js - Parse and convert asm.js to wasm a function at a time.

src/asmjs/asm-wasm-builder.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/v8.h"
 
 // Required to get M_E etc. in MSVC.
 #if defined(_WIN32)
 #define _USE_MATH_DEFINES
 #endif
 #include <math.h>
 
 #include "src/asmjs/asm-types.h"
 #include "src/asmjs/asm-wasm-builder.h"
 #include "src/wasm/switch-logic.h"
 #include "src/wasm/wasm-macro-gen.h"
 #include "src/wasm/wasm-opcodes.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/codegen.h"
+#include "src/compiler.h"
+#include "src/isolate.h"
+#include "src/parsing/parse-info.h"
 
 namespace v8 {
 namespace internal {
 namespace wasm {
 
 #define RECURSE(call)               \
   do {                              \
     DCHECK(!HasStackOverflow());    \
     call;                           \
     if (HasStackOverflow()) return; \
   } while (false)
 
 enum AsmScope { kModuleScope, kInitScope, kFuncScope, kExportScope };
 enum ValueFate { kDrop, kLeaveOnStack };
 
 struct ForeignVariable {
   Handle<Name> name;
   Variable* var;
   LocalType type;
 };
 
 class AsmWasmBuilderImpl final : public AstVisitor<AsmWasmBuilderImpl> {
  public:
-  AsmWasmBuilderImpl(Isolate* isolate, Zone* zone, FunctionLiteral* literal,
-                     AsmTyper* typer)
+  AsmWasmBuilderImpl(Isolate* isolate, Zone* zone, Script* script,
+                     FunctionLiteral* literal, AsmTyper* typer)
       : local_variables_(ZoneHashMap::kDefaultHashMapCapacity,
                          ZoneAllocationPolicy(zone)),
         functions_(ZoneHashMap::kDefaultHashMapCapacity,
                    ZoneAllocationPolicy(zone)),
         global_variables_(ZoneHashMap::kDefaultHashMapCapacity,
                           ZoneAllocationPolicy(zone)),
         scope_(kModuleScope),
         builder_(new (zone) WasmModuleBuilder(zone)),
         current_function_builder_(nullptr),
         literal_(literal),
         isolate_(isolate),
         zone_(zone),
+        script_(script),
         typer_(typer),
+        typer_failed_(false),
         breakable_blocks_(zone),
         foreign_variables_(zone),
         init_function_(nullptr),
         foreign_init_function_(nullptr),
-        next_table_index_(0),
         function_tables_(ZoneHashMap::kDefaultHashMapCapacity,
                          ZoneAllocationPolicy(zone)),
         imported_function_table_(this) {
     InitializeAstVisitor(isolate);
   }
 
   void InitializeInitFunction() {
     FunctionSig::Builder b(zone(), 0, 0);
     init_function_ = builder_->AddFunction(b.Build());
     builder_->MarkStartFunction(init_function_);
@@ skipping 26 matching lines @@
   i::Handle<i::FixedArray> GetForeignArgs() {
     i::Handle<FixedArray> ret = isolate_->factory()->NewFixedArray(
         static_cast<int>(foreign_variables_.size()));
     for (size_t i = 0; i < foreign_variables_.size(); ++i) {
       ForeignVariable* fv = &foreign_variables_[i];
       ret->set(static_cast<int>(i), *fv->name);
     }
     return ret;
   }
 
-  void Build() {
+  bool Build() {
     InitializeInitFunction();
-    RECURSE(VisitFunctionLiteral(literal_));
+    if (!typer_->ValidatePhase1of2()) {
+      return false;
+    }
+    DCHECK(!HasStackOverflow());
+    VisitFunctionLiteral(literal_);
+    if (HasStackOverflow()) {
+      return false;
+    }
+    if (typer_failed_) {
+      return false;
+    }
     BuildForeignInitFunction();
+    return true;
   }
 
   void VisitVariableDeclaration(VariableDeclaration* decl) {}
 
   void VisitFunctionDeclaration(FunctionDeclaration* decl) {
     DCHECK_EQ(kModuleScope, scope_);
     DCHECK_NULL(current_function_builder_);
+    bool had_body;
+    i::Zone zone(isolate_->allocator());
+    if (decl->fun()->body() == nullptr) {
+      Handle<SharedFunctionInfo> shared =

[titzer, 2016/10/07 12:56:59]

Do we really need a shared function info here? Seems wasteful.

[bradn, 2016/11/25 09:19:36]

A large number of places in the parser assume a SharedFunctionInfo in the case
you're parsing one function.
Added a TODO to refactor to avoid needing this.

+          i::Compiler::NewSharedFunctionInfoFromLiteral(
+              isolate_, decl->fun(), handle(script_, isolate_));
+      shared->set_is_toplevel(false);
+      i::ParseInfo info(&zone, handle(script_, isolate_));
+      info.set_shared_info(shared);
+      info.set_language_mode(decl->fun()->scope()->language_mode());
+      info.set_lazy(true);
+      info.set_allow_lazy_parsing(false);
+      info.set_script_scope(decl->fun()->scope());
+      if (!i::Compiler::ParseAndAnalyze(&info)) {
+        typer_failed_ = true;
+        return;
+      }
+      FunctionLiteral* func = info.literal();
+      DCHECK_NOT_NULL(func);
+      decl->fun()->set_body(func->body());
+      had_body = false;
+    } else {
+      had_body = true;
+    }
+    if (!typer_->ValidateInnerFunction(decl)) {
+      typer_failed_ = true;
+      return;
+    }
     current_function_builder_ = LookupOrInsertFunction(decl->proxy()->var());
     scope_ = kFuncScope;
     RECURSE(Visit(decl->fun()));
+    if (!had_body) {
+      decl->fun()->set_body(nullptr);
+    }
     scope_ = kModuleScope;
     current_function_builder_ = nullptr;
     local_variables_.Clear();
   }
 
   void VisitStatements(ZoneList<Statement*>* stmts) {
     for (int i = 0; i < stmts->length(); ++i) {
       Statement* stmt = stmts->at(i);
       ExpressionStatement* e = stmt->AsExpressionStatement();
       if (e != nullptr && e->expression()->IsUndefinedLiteral()) {
         continue;
       }
       RECURSE(Visit(stmt));
+      if (typer_failed_) break;
       if (stmt->IsJump()) break;
     }
   }
 
   void VisitBlock(Block* stmt) {
     if (stmt->statements()->length() == 1) {
       ExpressionStatement* expr =
           stmt->statements()->at(0)->AsExpressionStatement();
       if (expr != nullptr) {
         if (expr->expression()->IsAssignment()) {
@@ skipping 299 matching lines @@
         const auto& arguments = func_type->Arguments();
         for (int i = 0; i < expr->parameter_count(); ++i) {
           LocalType type = TypeFrom(arguments[i]);
           DCHECK_NE(kAstStmt, type);
           InsertParameter(scope->parameter(i), type, i);
         }
       } else {
         UNREACHABLE();
       }
     }
-    RECURSE(VisitStatements(expr->body()));
-    RECURSE(VisitDeclarations(scope->declarations()));
+    if (scope_ == kFuncScope) {

[titzer, 2016/10/07 12:56:59]

Why do we need to do the declarations after for a func scope?

[bradn, 2016/11/25 09:19:36]

No good reason.
Both should be declarations then statements (in the new traversal).
Changed.

+      RECURSE(VisitStatements(expr->body()));
+      RECURSE(VisitDeclarations(scope->declarations()));
+    } else {
+      RECURSE(VisitDeclarations(scope->declarations()));
+      RECURSE(VisitStatements(expr->body()));
+    }
   }
 
   void VisitNativeFunctionLiteral(NativeFunctionLiteral* expr) {
     UNREACHABLE();
   }
 
   void VisitConditional(Conditional* expr) {
     DCHECK_EQ(kFuncScope, scope_);
     RECURSE(Visit(expr->condition()));
     // WASM ifs come with implicit blocks for both arms.
@@ skipping 161 matching lines @@
       byte code[] = {WASM_F32(val)};
       current_function_builder_->EmitCode(code, sizeof(code));
     } else {
       UNREACHABLE();
     }
   }
 
   void VisitRegExpLiteral(RegExpLiteral* expr) { UNREACHABLE(); }
 
   void VisitObjectLiteral(ObjectLiteral* expr) {
+    if (!typer_->ValidatePhase2of2()) {
+      typer_failed_ = true;
+      return;
+    }
+
     ZoneList<ObjectLiteralProperty*>* props = expr->properties();
     for (int i = 0; i < props->length(); ++i) {
       ObjectLiteralProperty* prop = props->at(i);
       DCHECK_EQ(kExportScope, scope_);
       VariableProxy* expr = prop->value()->AsVariableProxy();
       DCHECK_NOT_NULL(expr);
       Variable* var = expr->var();
       Literal* name = prop->key()->AsLiteral();
       DCHECK_NOT_NULL(name);
       DCHECK(name->IsPropertyName());
@@ skipping 12 matching lines @@
   void LoadInitFunction() {
     current_function_builder_ = init_function_;
     scope_ = kInitScope;
   }
 
   void UnLoadInitFunction() {
     scope_ = kModuleScope;
     current_function_builder_ = nullptr;
   }
 
-  void AddFunctionTable(VariableProxy* table, ArrayLiteral* funcs) {
-    auto* func_tbl_type = typer_->TypeOf(funcs)->AsFunctionTableType();
-    DCHECK_NOT_NULL(func_tbl_type);
-    auto* func_type = func_tbl_type->signature()->AsFunctionType();
+  struct FunctionTableIndices : public ZoneObject {
+    uint32_t start_index;
+    uint32_t signature_index;
+  };
+
+  FunctionTableIndices* LookupOrAddFunctionTable(VariableProxy* table,
+                                                 Property* p) {
+    FunctionTableIndices* indices = LookupFunctionTable(table->var());
+    if (indices != nullptr) {
+      // Already setup.
+      return indices;
+    }
+    indices = new (zone()) FunctionTableIndices();
+    auto* func_type = typer_->TypeOf(p)->AsFunctionType();
+    auto* func_table_type = typer_->TypeOf(p->obj()->AsVariableProxy()->var())
+                                ->AsFunctionTableType();
     const auto& arguments = func_type->Arguments();
     LocalType return_type = TypeFrom(func_type->ReturnType());
     FunctionSig::Builder sig(zone(), return_type == kAstStmt ? 0 : 1,
                              arguments.size());
     if (return_type != kAstStmt) {
       sig.AddReturn(return_type);
     }
     for (auto* arg : arguments) {
       sig.AddParam(TypeFrom(arg));
     }
     uint32_t signature_index = builder_->AddSignature(sig.Build());
-    InsertFunctionTable(table->var(), next_table_index_, signature_index);
-    next_table_index_ += funcs->values()->length();
-    for (int i = 0; i < funcs->values()->length(); ++i) {
-      VariableProxy* func = funcs->values()->at(i)->AsVariableProxy();
-      DCHECK_NOT_NULL(func);
-      builder_->AddIndirectFunction(
-          LookupOrInsertFunction(func->var())->func_index());
-    }
-  }
-
-  struct FunctionTableIndices : public ZoneObject {
-    uint32_t start_index;
-    uint32_t signature_index;
-  };
-
-  void InsertFunctionTable(Variable* v, uint32_t start_index,
-                           uint32_t signature_index) {
-    FunctionTableIndices* container = new (zone()) FunctionTableIndices();
-    container->start_index = start_index;
-    container->signature_index = signature_index;
+    indices->start_index =
+        builder_->AllocateIndirectFunctions(func_table_type->length());
+    indices->signature_index = signature_index;
     ZoneHashMap::Entry* entry = function_tables_.LookupOrInsert(
-        v, ComputePointerHash(v), ZoneAllocationPolicy(zone()));
-    entry->value = container;
+        table->var(), ComputePointerHash(table->var()),
+        ZoneAllocationPolicy(zone()));
+    entry->value = indices;
+    return indices;
   }
 
   FunctionTableIndices* LookupFunctionTable(Variable* v) {
     ZoneHashMap::Entry* entry =
         function_tables_.Lookup(v, ComputePointerHash(v));
-    DCHECK_NOT_NULL(entry);
+    if (entry == nullptr) {
+      return nullptr;
+    }
     return reinterpret_cast<FunctionTableIndices*>(entry->value);
   }
 
+  void PopulateFunctionTable(VariableProxy* table, ArrayLiteral* funcs) {
+    FunctionTableIndices* indices = LookupFunctionTable(table->var());
+    DCHECK_NOT_NULL(indices);
+    for (int i = 0; i < funcs->values()->length(); ++i) {
+      VariableProxy* func = funcs->values()->at(i)->AsVariableProxy();
+      DCHECK_NOT_NULL(func);
+      builder_->SetIndirectFunction(
+          indices->start_index + i,
+          LookupOrInsertFunction(func->var())->func_index());
+    }
+  }
+
   class ImportedFunctionTable {
    private:
     class ImportedFunctionIndices : public ZoneObject {
      public:
       const char* name_;
       int name_length_;
       WasmModuleBuilder::SignatureMap signature_to_index_;
 
       ImportedFunctionIndices(const char* name, int name_length, Zone* zone)
           : name_(name), name_length_(name_length), signature_to_index_(zone) {}
     };
     ZoneHashMap table_;
     AsmWasmBuilderImpl* builder_;
 
    public:
     explicit ImportedFunctionTable(AsmWasmBuilderImpl* builder)
         : table_(ZoneHashMap::kDefaultHashMapCapacity,
                  ZoneAllocationPolicy(builder->zone())),
           builder_(builder) {}
 
-    void AddImport(Variable* v, const char* name, int name_length) {
-      ImportedFunctionIndices* indices = new (builder_->zone())
-          ImportedFunctionIndices(name, name_length, builder_->zone());
+    ImportedFunctionIndices* LookupOrInsertImport(Variable* v) {
       auto* entry = table_.LookupOrInsert(
           v, ComputePointerHash(v), ZoneAllocationPolicy(builder_->zone()));
-      entry->value = indices;
+      ImportedFunctionIndices* indices;
+      if (entry->value == nullptr) {
+        indices = new (builder_->zone())
+            ImportedFunctionIndices(nullptr, 0, builder_->zone());
+        entry->value = indices;
+      } else {
+        indices = reinterpret_cast<ImportedFunctionIndices*>(entry->value);
+      }
+      return indices;
+    }
+
+    void SetImportName(Variable* v, const char* name, int name_length) {
+      auto* indices = LookupOrInsertImport(v);
+      indices->name_ = name;
+      indices->name_length_ = name_length;
+      for (auto i : indices->signature_to_index_) {
+        builder_->builder_->SetImportName(i.second, indices->name_,
+                                          indices->name_length_);
+      }
     }
 
     // Get a function's index (or allocate if new).
-    uint32_t LookupOrInsertImport(Variable* v, FunctionSig* sig) {
-      ZoneHashMap::Entry* entry = table_.Lookup(v, ComputePointerHash(v));
-      DCHECK_NOT_NULL(entry);
-      ImportedFunctionIndices* indices =
-          reinterpret_cast<ImportedFunctionIndices*>(entry->value);
+    uint32_t LookupOrInsertImportUse(Variable* v, FunctionSig* sig) {
+      auto* indices = LookupOrInsertImport(v);
       WasmModuleBuilder::SignatureMap::iterator pos =
           indices->signature_to_index_.find(sig);
       if (pos != indices->signature_to_index_.end()) {
         return pos->second;
       } else {
         uint32_t index = builder_->builder_->AddImport(
             indices->name_, indices->name_length_, sig);
         indices->signature_to_index_[sig] = index;
         return index;
       }
@@ skipping 140 matching lines @@
       }
       Property* prop = expr->value()->AsProperty();
       if (prop != nullptr) {
         VariableProxy* vp = prop->obj()->AsVariableProxy();
         if (vp != nullptr && vp->var()->IsParameter() &&
             vp->var()->index() == 1) {
           VariableProxy* target = expr->target()->AsVariableProxy();
           if (typer_->TypeOf(target)->AsFFIType() != nullptr) {
             const AstRawString* name =
                 prop->key()->AsLiteral()->AsRawPropertyName();
-            imported_function_table_.AddImport(
+            imported_function_table_.SetImportName(
                 target->var(), reinterpret_cast<const char*>(name->raw_data()),
                 name->length());
           }
         }
         // Property values in module scope don't emit code, so return.
         return;
       }
       ArrayLiteral* funcs = expr->value()->AsArrayLiteral();
-      if (funcs != nullptr &&
-          typer_->TypeOf(funcs)
-              ->AsFunctionTableType()
-              ->signature()
-              ->AsFunctionType()) {
+      if (funcs != nullptr) {
         VariableProxy* target = expr->target()->AsVariableProxy();
         DCHECK_NOT_NULL(target);
-        AddFunctionTable(target, funcs);
+        PopulateFunctionTable(target, funcs);
         // Only add to the function table. No init needed.
         return;
       }
       if (expr->value()->IsCallNew()) {
         // No init code to emit for CallNew nodes.
         return;
       }
       as_init = true;
     }
 
@@ skipping 414 matching lines @@
           FunctionSig::Builder sig(zone(), return_type == kAstStmt ? 0 : 1,
                                    args->length());
           if (return_type != kAstStmt) {
             sig.AddReturn(return_type);
           } else {
             returns_value = false;
           }
           for (int i = 0; i < args->length(); ++i) {
             sig.AddParam(TypeOf(args->at(i)));
           }
-          uint32_t index = imported_function_table_.LookupOrInsertImport(
+          uint32_t index = imported_function_table_.LookupOrInsertImportUse(
               vp->var(), sig.Build());
           VisitCallArgs(expr);
           current_function_builder_->Emit(kExprCallFunction);
           current_function_builder_->EmitVarInt(index);
         } else {
           WasmFunctionBuilder* function = LookupOrInsertFunction(vp->var());
           VisitCallArgs(expr);
           current_function_builder_->Emit(kExprCallFunction);
           current_function_builder_->EmitDirectCallIndex(
               function->func_index());
           returns_value = function->signature()->return_count() > 0;
         }
         break;
       }
       case Call::KEYED_PROPERTY_CALL: {
         DCHECK_EQ(kFuncScope, scope_);
         Property* p = expr->expression()->AsProperty();
         DCHECK_NOT_NULL(p);
         VariableProxy* var = p->obj()->AsVariableProxy();
         DCHECK_NOT_NULL(var);
-        FunctionTableIndices* indices = LookupFunctionTable(var->var());
+        FunctionTableIndices* indices = LookupOrAddFunctionTable(var, p);
         Visit(p->key());  // TODO(titzer): should use RECURSE()
 
         // We have to use a temporary for the correct order of evaluation.
         current_function_builder_->EmitI32Const(indices->start_index);
         current_function_builder_->Emit(kExprI32Add);
         WasmTemporary tmp(current_function_builder_, kAstI32);
         current_function_builder_->EmitSetLocal(tmp.index());
 
         VisitCallArgs(expr);
 
@@ skipping 324 matching lines @@
 #undef NON_SIGNED_INT
 #undef SIGNED
 #undef NON_SIGNED
 
   void VisitThisFunction(ThisFunction* expr) { UNREACHABLE(); }
 
   void VisitDeclarations(ZoneList<Declaration*>* decls) {
     for (int i = 0; i < decls->length(); ++i) {
       Declaration* decl = decls->at(i);
       RECURSE(Visit(decl));
+      if (typer_failed_) {
+        return;
+      }
     }
   }
 
   void VisitClassLiteral(ClassLiteral* expr) { UNREACHABLE(); }
 
   void VisitSpread(Spread* expr) { UNREACHABLE(); }
 
   void VisitSuperPropertyReference(SuperPropertyReference* expr) {
     UNREACHABLE();
   }
@@ skipping 107 matching lines @@
 
   ZoneHashMap local_variables_;
   ZoneHashMap functions_;
   ZoneHashMap global_variables_;
   AsmScope scope_;
   WasmModuleBuilder* builder_;
   WasmFunctionBuilder* current_function_builder_;
   FunctionLiteral* literal_;
   Isolate* isolate_;
   Zone* zone_;
+  Script* script_;
   AsmTyper* typer_;
+  bool typer_failed_;
   ZoneVector<std::pair<BreakableStatement*, bool>> breakable_blocks_;
   ZoneVector<ForeignVariable> foreign_variables_;
   WasmFunctionBuilder* init_function_;
   WasmFunctionBuilder* foreign_init_function_;
   uint32_t next_table_index_;
   ZoneHashMap function_tables_;
   ImportedFunctionTable imported_function_table_;
 
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AsmWasmBuilderImpl);
 };
 
-AsmWasmBuilder::AsmWasmBuilder(Isolate* isolate, Zone* zone,
-                               FunctionLiteral* literal, AsmTyper* typer)
-    : isolate_(isolate), zone_(zone), literal_(literal), typer_(typer) {}
+AsmWasmBuilder::AsmWasmBuilder(Isolate* isolate, Zone* zone, Script* script,
+                               FunctionLiteral* literal)
+    : isolate_(isolate),
+      zone_(zone),
+      script_(script),
+      literal_(literal),
+      typer_(isolate, zone, script, literal) {}
 
 // TODO(aseemgarg): probably should take zone (to write wasm to) as input so
 // that zone in constructor may be thrown away once wasm module is written.
 ZoneBuffer* AsmWasmBuilder::Run(i::Handle<i::FixedArray>* foreign_args) {
-  AsmWasmBuilderImpl impl(isolate_, zone_, literal_, typer_);
-  impl.Build();
+  AsmWasmBuilderImpl impl(isolate_, zone_, script_, literal_, &typer_);
+  if (!impl.Build()) {
+    return nullptr;
+  }
   *foreign_args = impl.GetForeignArgs();
   ZoneBuffer* buffer = new (zone_) ZoneBuffer(zone_);
   impl.builder_->WriteTo(*buffer);
   return buffer;
 }
 
 const char* AsmWasmBuilder::foreign_init_name = "__foreign_init__";
 const char* AsmWasmBuilder::single_function_name = "__single_function__";
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8