Index: src/asmjs/asm-scanner.h |
diff --git a/src/asmjs/asm-scanner.h b/src/asmjs/asm-scanner.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..1e4b9f3d3f369e2994d6847a0be1f2a8eea53627 |
--- /dev/null |
+++ b/src/asmjs/asm-scanner.h |
@@ -0,0 +1,158 @@ |
+// 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_SCANNER_H_ |
+#define V8_ASMJS_ASM_SCANNER_H_ |
+ |
+#include <memory> |
+#include <string> |
+#include <unordered_map> |
+ |
+#include "src/asmjs/asm-names.h" |
+#include "src/base/logging.h" |
+#include "src/globals.h" |
+ |
+namespace v8 { |
+namespace internal { |
+ |
+class Utf16CharacterStream; |
+ |
+// A custom scanner to extract the token stream needed to parse valid |
+// asm.js: http://asmjs.org/spec/latest/ |
+// This scanner intentionally avoids the portion of JavaScript lexing |
+// that are not required to determine if code is valid asm.js code. |
+// * Strings are disallowed except for 'use asm'. |
+// * Only the subset of keywords needed to check asm.js invariants are |
+// included. |
+// * Identifiers are accumulated into local + global string tables |
+// (for performance). |
+class V8_EXPORT_PRIVATE AsmJsScanner { |
+ public: |
+ typedef int32_t token_t; |
+ |
+ AsmJsScanner(); |
+ // Pick the stream to parse (must be called before anything else). |
+ void SetStream(std::unique_ptr<Utf16CharacterStream> stream); |
+ |
+ // Get current token. |
+ token_t Token() const { return token_; } |
+ // Advance to the next token. |
+ void Next(); |
+ // Back up by one token. |
+ void Rewind(); |
+ // Get raw string for current identifier. |
+ const std::string& GetIdentifierString() const { |
+ // Identifier strings don't work after a rewind. |
+ DCHECK(!rewind_); |
+ return identifier_string_; |
+ } |
+ // Check if we just passed a newline. |
+ bool IsPrecededByNewline() const { |
+ // Newline tracking doesn't work if you back up. |
+ DCHECK(!rewind_); |
+ return preceded_by_newline_; |
+ } |
+ |
+#if DEBUG |
+ // Debug only method to go from a token back to its name. |
+ // Slow, only use for debugging. |
+ std::string Name(token_t token) const; |
+#endif |
+ |
+ // Get current position (to use with Seek). |
+ int GetPosition() const; |
+ // Restores old position (token after that position). |
+ void Seek(int pos); |
+ |
+ // Select whether identifiers are resolved in global or local scope, |
+ // and which scope new identifiers are added to. |
+ void EnterLocalScope() { in_local_scope_ = true; } |
+ void EnterGlobalScope() { in_local_scope_ = false; } |
+ // Drop all current local identifiers. |
+ void ResetLocals(); |
+ |
+ // Methods to check if a token is an identifier and which scope. |
+ bool IsLocal() const { return IsLocal(Token()); } |
+ bool IsGlobal() const { return IsGlobal(Token()); } |
+ static bool IsLocal(token_t token) { return token <= kLocalsStart; } |
+ static bool IsGlobal(token_t token) { return token >= kGlobalsStart; } |
+ // Methods to find the index position of an identifier (count starting from |
+ // 0 for each scope separately). |
+ static size_t LocalIndex(token_t token) { |
+ DCHECK(IsLocal(token)); |
+ return -(token - kLocalsStart); |
+ } |
+ static size_t GlobalIndex(token_t token) { |
+ DCHECK(IsGlobal(token)); |
+ return token - kGlobalsStart; |
+ } |
+ |
+ // Methods to check if the current token is an asm.js "number" (contains a |
+ // dot) or an "unsigned" (a number without a dot). |
+ bool IsUnsigned() const { return Token() == kUnsigned; } |
+ uint64_t AsUnsigned() const { return unsigned_value_; } |
+ bool IsDouble() const { return Token() == kDouble; } |
+ double AsDouble() const { return double_value_; } |
+ |
+ // clang-format off |
+ enum { |
+ // [-10000 .. -10000-kMaxIdentifierCount) :: Local identifiers |
marja
2017/03/20 14:29:24
Nit: you probably meant:
[-10000-kMaxIdentifierCou
|
+ // [-10000 .. -1) :: Builtin tokens like keywords |
+ // (also includes some special |
+ // ones like end of input) |
+ // 0 .. 255 :: Single char tokens |
+ // 256 .. 256+kMaxIdentifierCount :: Global identifiers |
+ kLocalsStart = -10000, |
+#define V(name, _junk1, _junk2, _junk3) kToken_##name, |
+ STDLIB_MATH_FUNCTION_LIST(V) |
+ STDLIB_ARRAY_TYPE_LIST(V) |
+#undef V |
+#define V(name) kToken_##name, |
+ STDLIB_OTHER_LIST(V) |
+ STDLIB_MATH_VALUE_LIST(V) |
+ KEYWORD_NAME_LIST(V) |
+#undef V |
+#define V(rawname, name) kToken_##name, |
+ LONG_SYMBOL_NAME_LIST(V) |
+#undef V |
+#define V(name, value, string_name) name = value, |
+ SPECIAL_TOKEN_LIST(V) |
+#undef V |
+ kGlobalsStart = 256, |
+ }; |
+ // clang-format on |
+ |
+ private: |
+ std::unique_ptr<Utf16CharacterStream> stream_; |
+ token_t token_; |
+ token_t preceding_token_; |
+ token_t next_token_; |
+ bool rewind_; |
+ std::string identifier_string_; |
+ bool in_local_scope_; |
+ std::unordered_map<std::string, token_t> local_names_; |
+ std::unordered_map<std::string, token_t> global_names_; |
+ std::unordered_map<std::string, token_t> property_names_; |
+ int global_count_; |
+ double double_value_; |
+ uint64_t unsigned_value_; |
+ bool preceded_by_newline_; |
+ |
+ // Consume multiple characters. |
+ void ConsumeIdentifier(uc32 ch); |
+ void ConsumeNumber(uc32 ch); |
+ bool ConsumeCComment(); |
+ void ConsumeCPPComment(); |
+ void ConsumeString(uc32 quote); |
+ void ConsumeCompareOrShift(uc32 ch); |
+ |
+ // Classify character categories. |
+ bool IsIdentifierStart(uc32 ch); |
+ bool IsIdentifierPart(uc32 ch); |
+ bool IsNumberStart(uc32 ch); |
+}; |
+ |
+} // namespace internal |
+} // namespace v8 |
+#endif |