[wasm][asm.js] Asm.js -> wasm custom parser.

src/asmjs/asm-parser.h

Index: src/asmjs/asm-parser.h
diff --git a/src/asmjs/asm-parser.h b/src/asmjs/asm-parser.h
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+// Copyright 2017 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_ASMJS_ASM_PARSER_H_
+#define V8_ASMJS_ASM_PARSER_H_
+
+#include <list>
+#include <string>
+#include <vector>
+
+#include "src/asmjs/asm-scanner.h"
+#include "src/asmjs/asm-typer.h"
+#include "src/asmjs/asm-types.h"
+#include "src/wasm/signature-map.h"
+#include "src/wasm/wasm-module-builder.h"
+#include "src/zone/zone-containers.h"
+
+namespace v8 {
+namespace internal {
+namespace wasm {
+
+// A custom parser + validator + wasm converter for asm.js:
+// http://asmjs.org/spec/latest/
+// This parser intentionally avoids the portion of JavaScript parsing
+// that are not required to determine if code is valid asm.js code.
+// * It is mostly one pass.
+// * It bails out on unexpected input.
+// * It assumes strict ordering insofar as permitted by asm.js validation rules.
+// * It relies on a custom scanner that provides de-duped identifiers in two
+//   scopes (local + module wide).
+class AsmJsParser {
+ public:
+  explicit AsmJsParser(Isolate* isolate, Zone* zone, Handle<Script> script,
+                       int start, int end);
+  bool Run();
+  const char* failure_message() const { return failure_message_.c_str(); }
+  int failure_location() const { return failure_location_; }
+  WasmModuleBuilder* module_builder() { return module_builder_; }
+  const AsmTyper::StdlibSet* stdlib_uses() const { return &stdlib_uses_; }
+
+ private:
+  // clang-format off
+  enum class VarKind {
+    kUnused,
+    kLocal,
+    kGlobal,
+    kSpecial,
+    kFunction,
+    kTable,
+    kImportedFunction,
+#define V(_unused0, Name, _unused1, _unused2) kMath##Name,
+    STDLIB_MATH_FUNCTION_LIST(V)
+#undef V
+#define V(Name) kMath##Name,
+    STDLIB_MATH_VALUE_LIST(V)
+#undef V
+  };
+  // clang-format on
+
+  struct FunctionImportInfo {
+    std::string name;
+    SignatureMap cache;
+    std::vector<uint32_t> cache_index;
+  };
+
+  struct VarInfo {
+    AsmType* type;
+    WasmFunctionBuilder* function_builder;
+    FunctionImportInfo* import;
+    int32_t mask;
+    uint32_t index;
+    VarKind kind;
+    bool mutable_variable;
+    bool function_defined;
+
+    VarInfo();
+    void DeclareGlobalImport(AsmType* type, uint32_t index);
+    void DeclareStdlibFunc(VarKind kind, AsmType* type);
+  };
+
+  struct GlobalImport {
+    std::string import_name;
+    uint32_t import_index;
+    uint32_t global_index;
+    bool needs_init;
+  };
+
+  enum class BlockKind { kRegular, kLoop, kOther };
+
+  struct BlockInfo {
+    BlockKind kind;
+    AsmJsScanner::token_t label;
+  };
+
+  Zone* zone_;
+  AsmJsScanner scanner_;
+  WasmModuleBuilder* module_builder_;
+  WasmFunctionBuilder* current_function_builder_;
+  AsmType* return_type_;
+  std::uintptr_t stack_limit_;
+  AsmTyper::StdlibSet stdlib_uses_;
+  std::list<FunctionImportInfo> function_import_info_;
+  ZoneVector<VarInfo> global_var_info_;
+  ZoneVector<VarInfo> local_var_info_;
+
+  int function_temp_locals_offset_;
+  int function_temp_locals_used_;
+
+  // Error Handling related
+  bool failed_;
+  std::string failure_message_;
+  int failure_location_;
+
+  // Module Related.
+  AsmJsScanner::token_t stdlib_name_;
+  AsmJsScanner::token_t foreign_name_;
+  AsmJsScanner::token_t heap_name_;
+
+  static const AsmJsScanner::token_t kTokenNone = 0;
+
+  // Track if parsing a heap assignment.
+  bool inside_heap_assignment_;
+  AsmType* heap_access_type_;
+
+  ZoneVector<BlockInfo> block_stack_;
+
+  // Types used for stdlib function and their set up.
+  AsmType* stdlib_dq2d_;
+  AsmType* stdlib_dqdq2d_;
+  AsmType* stdlib_fq2f_;
+  AsmType* stdlib_i2s_;
+  AsmType* stdlib_ii2s_;
+  AsmType* stdlib_minmax_;
+  AsmType* stdlib_abs_;
+  AsmType* stdlib_ceil_like_;
+  AsmType* stdlib_fround_;
+
+  // When making calls, the return type is needed to lookup signatures.
+  // For +callsite(..) or fround(callsite(..)) use this value to pass
+  // along the coercion.
+  AsmType* call_coercion_;
+
+  // Used to track the last label we've seen so it can be matched to later
+  // statements it's attached to.
+  AsmJsScanner::token_t pending_label_;
+
+  // Global imports.
+  // NOTE: Holds the strings referenced in wasm-module-builder for imports.
+  ZoneLinkedList<GlobalImport> global_imports_;
+
+  Zone* zone() { return zone_; }
+
+  inline bool Peek(AsmJsScanner::token_t token) {
+    return scanner_.Token() == token;
+  }
+
+  inline bool Check(AsmJsScanner::token_t token) {
+    if (scanner_.Token() == token) {
+      scanner_.Next();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  inline bool CheckForZero() {
+    if (scanner_.IsUnsigned() && scanner_.AsUnsigned() == 0) {
+      scanner_.Next();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  inline bool CheckForDouble(double* value) {
+    if (scanner_.IsDouble()) {
+      *value = scanner_.AsDouble();
+      scanner_.Next();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  inline bool CheckForUnsigned(uint64_t* value) {
+    if (scanner_.IsUnsigned()) {
+      *value = scanner_.AsUnsigned();
+      scanner_.Next();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  inline bool CheckForUnsignedBelow(uint64_t limit, uint64_t* value) {
+    if (scanner_.IsUnsigned() && scanner_.AsUnsigned() < limit) {
+      *value = scanner_.AsUnsigned();
+      scanner_.Next();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  inline AsmJsScanner::token_t Consume() {
+    AsmJsScanner::token_t ret = scanner_.Token();
+    scanner_.Next();
+    return ret;
+  }
+
+  void SkipSemicolon();
+
+  VarInfo* GetVarInfo(AsmJsScanner::token_t token);
+  uint32_t VarIndex(VarInfo* info);
+  void DeclareGlobal(VarInfo* info, bool mutable_variable, AsmType* type,
+                     ValueType vtype,
+                     const WasmInitExpr& init = WasmInitExpr());
+
+  int32_t TempVariable(int i);
+
+  void AddGlobalImport(std::string name, AsmType* type, ValueType vtype,
+                       bool mutable_variable, VarInfo* info);
+
+  // Use to set up block stack layers (including synthetic ones for if-else).
+  // Begin/Loop/End below are implemented with these plus code generation.
+  void BareBegin(BlockKind kind = BlockKind::kOther,
+                 AsmJsScanner::token_t label = 0);
+  void BareEnd();
+  int FindContinueLabelDepth(AsmJsScanner::token_t label);
+  int FindBreakLabelDepth(AsmJsScanner::token_t label);
+
+  // Use to set up actual wasm blocks/loops.
+  void Begin(AsmJsScanner::token_t label = 0);
+  void Loop(AsmJsScanner::token_t label = 0);
+  void End();
+
+  void InitializeStdlibTypes();
+
+  FunctionSig* ConvertSignature(AsmType* return_type,
+                                const std::vector<AsmType*>& params);
+
+  // 6.1 ValidateModule
+  void ValidateModule();
+  void ValidateModuleParameters();
+  void ValidateModuleVars();
+  void ValidateModuleVar(bool mutable_variable);
+  bool ValidateModuleVarImport(VarInfo* info, bool mutable_variable);
+  void ValidateModuleVarStdlib(VarInfo* info);
+  void ValidateModuleVarNewStdlib(VarInfo* info);
+  void ValidateModuleVarFloat(VarInfo* info, bool mutable_variable);
+
+  void ValidateExport();         // 6.2 ValidateExport
+  void ValidateFunctionTable();  // 6.3 ValidateFunctionTable
+  void ValidateFunction();       // 6.4 ValidateFunction
+  void ValidateFunctionParams(std::vector<AsmType*>* params);
+  void ValidateFunctionLocals(size_t param_count,
+                              std::vector<ValueType>* locals);
+  void ValidateStatement();              // ValidateStatement
+  void Block();                          // 6.5.1 Block
+  void ExpressionStatement();            // 6.5.2 ExpressionStatement
+  void EmptyStatement();                 // 6.5.3 EmptyStatement
+  void IfStatement();                    // 6.5.4 IfStatement
+  void ReturnStatement();                // 6.5.5 ReturnStatement
+  bool IterationStatement();             // 6.5.6 IterationStatement
+  void WhileStatement();                 // 6.5.6 IterationStatement - while
+  void DoStatement();                    // 6.5.6 IterationStatement - do
+  void ForStatement();                   // 6.5.6 IterationStatement - for
+  void BreakStatement();                 // 6.5.7 BreakStatement
+  void ContinueStatement();              // 6.5.8 ContinueStatement
+  void LabelledStatement();              // 6.5.9 LabelledStatement
+  void SwitchStatement();                // 6.5.10 SwitchStatement
+  void ValidateCase();                   // 6.6. ValidateCase
+  void ValidateDefault();                // 6.7 ValidateDefault
+  AsmType* ValidateExpression();         // 6.8 ValidateExpression
+  AsmType* Expression(AsmType* expect);  // 6.8.1 Expression
+  AsmType* NumericLiteral();             // 6.8.2 NumericLiteral
+  AsmType* Identifier();                 // 6.8.3 Identifier
+  AsmType* CallExpression();             // 6.8.4 CallExpression
+  AsmType* MemberExpression();           // 6.8.5 MemberExpression
+  AsmType* AssignmentExpression();       // 6.8.6 AssignmentExpression
+  AsmType* UnaryExpression();            // 6.8.7 UnaryExpression
+  AsmType* MultiplicativeExpression();   // 6.8.8 MultaplicativeExpression
+  AsmType* AdditiveExpression();         // 6.8.9 AdditiveExpression
+  AsmType* ShiftExpression();            // 6.8.10 ShiftExpression
+  AsmType* RelationalExpression();       // 6.8.11 RelationalExpression
+  AsmType* EqualityExpression();         // 6.8.12 EqualityExpression
+  AsmType* BitwiseANDExpression();       // 6.8.13 BitwiseANDExpression
+  AsmType* BitwiseXORExpression();       // 6.8.14 BitwiseXORExpression
+  AsmType* BitwiseORExpression();        // 6.8.15 BitwiseORExpression
+  AsmType* ConditionalExpression();      // 6.8.16 ConditionalExpression
+  AsmType* ParenthesizedExpression();    // 6.8.17 ParenthesiedExpression
+  AsmType* ValidateCall();               // 6.9 ValidateCall
+  bool PeekCall();                       // 6.9 ValidateCall - helper
+  void ValidateHeapAccess();             // 6.10 ValidateHeapAccess
+  void ValidateFloatCoercion();          // 6.11 ValidateFloatCoercion
+
+  void GatherCases(std::vector<int32_t>* cases);
+};
+
+}  // namespace wasm
+}  // namespace internal
+}  // namespace v8
+#endif