Merge up to 8597 to experimental/gc from the bleeding edge.

src/jsregexp.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 109 matching lines @@
   Handle<FixedArray> cached = compilation_cache->LookupRegExp(pattern, flags);
   bool in_cache = !cached.is_null();
   LOG(isolate, RegExpCompileEvent(re, in_cache));
 
   Handle<Object> result;
   if (in_cache) {
     re->set_data(*cached);
     return re;
   }
   pattern = FlattenGetString(pattern);
-  CompilationZoneScope zone_scope(isolate, DELETE_ON_EXIT);
+  ZoneScope zone_scope(isolate, DELETE_ON_EXIT);
   PostponeInterruptsScope postpone(isolate);
   RegExpCompileData parse_result;
   FlatStringReader reader(isolate, pattern);
   if (!RegExpParser::ParseRegExp(&reader, flags.is_multiline(),
                                  &parse_result)) {
     // Throw an exception if we fail to parse the pattern.
     ThrowRegExpException(re,
                          pattern,
                          parse_result.error,
                          "malformed_regexp");
@@ skipping 147 matching lines @@
 // from the source pattern.
 // If compilation fails, an exception is thrown and this function
 // returns false.
 bool RegExpImpl::EnsureCompiledIrregexp(Handle<JSRegExp> re, bool is_ascii) {
   Object* compiled_code = re->DataAt(JSRegExp::code_index(is_ascii));
 #ifdef V8_INTERPRETED_REGEXP
   if (compiled_code->IsByteArray()) return true;
 #else  // V8_INTERPRETED_REGEXP (RegExp native code)
   if (compiled_code->IsCode()) return true;
 #endif
+  // We could potentially have marked this as flushable, but have kept
+  // a saved version if we did not flush it yet.
+  Object* saved_code = re->DataAt(JSRegExp::saved_code_index(is_ascii));
+  if (saved_code->IsCode()) {
+    // Reinstate the code in the original place.
+    re->SetDataAt(JSRegExp::code_index(is_ascii), saved_code);
+    ASSERT(compiled_code->IsSmi());
+    return true;
+  }
   return CompileIrregexp(re, is_ascii);
 }
 
 
+static bool CreateRegExpErrorObjectAndThrow(Handle<JSRegExp> re,
+                                            bool is_ascii,
+                                            Handle<String> error_message,
+                                            Isolate* isolate) {
+  Factory* factory = isolate->factory();
+  Handle<FixedArray> elements = factory->NewFixedArray(2);
+  elements->set(0, re->Pattern());
+  elements->set(1, *error_message);
+  Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
+  Handle<Object> regexp_err =
+      factory->NewSyntaxError("malformed_regexp", array);
+  isolate->Throw(*regexp_err);
+  return false;
+}
+
+
 bool RegExpImpl::CompileIrregexp(Handle<JSRegExp> re, bool is_ascii) {
   // Compile the RegExp.
   Isolate* isolate = re->GetIsolate();
-  CompilationZoneScope zone_scope(isolate, DELETE_ON_EXIT);
+  ZoneScope zone_scope(isolate, DELETE_ON_EXIT);
   PostponeInterruptsScope postpone(isolate);
+  // If we had a compilation error the last time this is saved at the
+  // saved code index.
   Object* entry = re->DataAt(JSRegExp::code_index(is_ascii));
-  if (entry->IsJSObject()) {
-    // If it's a JSObject, a previous compilation failed and threw this object.
-    // Re-throw the object without trying again.
-    isolate->Throw(entry);
+  // When arriving here entry can only be a smi, either representing an
+  // uncompiled regexp, a previous compilation error, or code that has
+  // been flushed.
+  ASSERT(entry->IsSmi());
+  int entry_value = Smi::cast(entry)->value();
+  ASSERT(entry_value == JSRegExp::kUninitializedValue ||
+         entry_value == JSRegExp::kCompilationErrorValue ||
+         (entry_value < JSRegExp::kCodeAgeMask && entry_value >= 0));
+
+  if (entry_value == JSRegExp::kCompilationErrorValue) {
+    // A previous compilation failed and threw an error which we store in
+    // the saved code index (we store the error message, not the actual
+    // error). Recreate the error object and throw it.
+    Object* error_string = re->DataAt(JSRegExp::saved_code_index(is_ascii));
+    ASSERT(error_string->IsString());
+    Handle<String> error_message(String::cast(error_string));
+    CreateRegExpErrorObjectAndThrow(re, is_ascii, error_message, isolate);
     return false;
   }
-  ASSERT(entry->IsTheHole());
 
   JSRegExp::Flags flags = re->GetFlags();
 
   Handle<String> pattern(re->Pattern());
   if (!pattern->IsFlat()) {
     FlattenString(pattern);
   }
 
   RegExpCompileData compile_data;
   FlatStringReader reader(isolate, pattern);
   if (!RegExpParser::ParseRegExp(&reader, flags.is_multiline(),
                                  &compile_data)) {
     // Throw an exception if we fail to parse the pattern.
     // THIS SHOULD NOT HAPPEN. We already pre-parsed it successfully once.
     ThrowRegExpException(re,
                          pattern,
                          compile_data.error,
                          "malformed_regexp");
     return false;
   }
   RegExpEngine::CompilationResult result =
       RegExpEngine::Compile(&compile_data,
                             flags.is_ignore_case(),
                             flags.is_multiline(),
                             pattern,
                             is_ascii);
   if (result.error_message != NULL) {
     // Unable to compile regexp.
-    Factory* factory = isolate->factory();
-    Handle<FixedArray> elements = factory->NewFixedArray(2);
-    elements->set(0, *pattern);
     Handle<String> error_message =
-        factory->NewStringFromUtf8(CStrVector(result.error_message));
-    elements->set(1, *error_message);
-    Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
-    Handle<Object> regexp_err =
-        factory->NewSyntaxError("malformed_regexp", array);
-    isolate->Throw(*regexp_err);
-    re->SetDataAt(JSRegExp::code_index(is_ascii), *regexp_err);
+        isolate->factory()->NewStringFromUtf8(CStrVector(result.error_message));
+    CreateRegExpErrorObjectAndThrow(re, is_ascii, error_message, isolate);
     return false;
   }
 
   Handle<FixedArray> data = Handle<FixedArray>(FixedArray::cast(re->data()));
   data->set(JSRegExp::code_index(is_ascii), result.code);
   int register_max = IrregexpMaxRegisterCount(*data);
   if (result.num_registers > register_max) {
     SetIrregexpMaxRegisterCount(*data, result.num_registers);
   }
 
@@ skipping 89 matching lines @@
 
   // A flat ASCII string might have a two-byte first part.
   if (subject->IsConsString()) {
     subject = Handle<String>(ConsString::cast(*subject)->first(), isolate);
   }
 
 #ifndef V8_INTERPRETED_REGEXP
   ASSERT(output.length() >= (IrregexpNumberOfCaptures(*irregexp) + 1) * 2);
   do {
     bool is_ascii = subject->IsAsciiRepresentation();
+    EnsureCompiledIrregexp(regexp, is_ascii);
     Handle<Code> code(IrregexpNativeCode(*irregexp, is_ascii), isolate);
     NativeRegExpMacroAssembler::Result res =
         NativeRegExpMacroAssembler::Match(code,
                                           subject,
                                           output.start(),
                                           output.length(),
                                           index,
                                           isolate);
     if (res != NativeRegExpMacroAssembler::RETRY) {
       ASSERT(res != NativeRegExpMacroAssembler::EXCEPTION ||
@@ skipping 330 matching lines @@
   static const int kMaxRecursion = 100;
   inline int recursion_depth() { return recursion_depth_; }
   inline void IncrementRecursionDepth() { recursion_depth_++; }
   inline void DecrementRecursionDepth() { recursion_depth_--; }
 
   void SetRegExpTooBig() { reg_exp_too_big_ = true; }
 
   inline bool ignore_case() { return ignore_case_; }
   inline bool ascii() { return ascii_; }
 
+  int current_expansion_factor() { return current_expansion_factor_; }
+  void set_current_expansion_factor(int value) {
+    current_expansion_factor_ = value;
+  }
+
   static const int kNoRegister = -1;
+
  private:
   EndNode* accept_;
   int next_register_;
   List<RegExpNode*>* work_list_;
   int recursion_depth_;
   RegExpMacroAssembler* macro_assembler_;
   bool ignore_case_;
   bool ascii_;
   bool reg_exp_too_big_;
+  int current_expansion_factor_;
 };
 
 
 class RecursionCheck {
  public:
   explicit RecursionCheck(RegExpCompiler* compiler) : compiler_(compiler) {
     compiler->IncrementRecursionDepth();
   }
   ~RecursionCheck() { compiler_->DecrementRecursionDepth(); }
  private:
   RegExpCompiler* compiler_;
 };
 
 
 static RegExpEngine::CompilationResult IrregexpRegExpTooBig() {
   return RegExpEngine::CompilationResult("RegExp too big");
 }
 
 
 // Attempts to compile the regexp using an Irregexp code generator.  Returns
 // a fixed array or a null handle depending on whether it succeeded.
 RegExpCompiler::RegExpCompiler(int capture_count, bool ignore_case, bool ascii)
     : next_register_(2 * (capture_count + 1)),
       work_list_(NULL),
       recursion_depth_(0),
       ignore_case_(ignore_case),
       ascii_(ascii),
-      reg_exp_too_big_(false) {
+      reg_exp_too_big_(false),
+      current_expansion_factor_(1) {
   accept_ = new EndNode(EndNode::ACCEPT);
   ASSERT(next_register_ - 1 <= RegExpMacroAssembler::kMaxRegister);
 }
 
 
 RegExpEngine::CompilationResult RegExpCompiler::Assemble(
     RegExpMacroAssembler* macro_assembler,
     RegExpNode* start,
     int capture_count,
     Handle<String> pattern) {
@@ skipping 1899 matching lines @@
   ~AlternativeGenerationList() {
     for (int i = kAFew; i < alt_gens_.length(); i++) {
       delete alt_gens_[i];
       alt_gens_[i] = NULL;
     }
   }
 
   AlternativeGeneration* at(int i) {
     return alt_gens_[i];
   }
+
  private:
   static const int kAFew = 10;
   ZoneList<AlternativeGeneration*> alt_gens_;
   AlternativeGeneration a_few_alt_gens_[kAFew];
 };
 
 
 /* Code generation for choice nodes.
  *
  * We generate quick checks that do a mask and compare to eliminate a
@@ skipping 539 matching lines @@
     int priority = 0;
     for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
       if (out_set->Get(i)) {
         if (priority > 0) stream()->Add("|");
         stream()->Add("<s%io%i> %i", from, i, priority);
         priority++;
       }
     }
     stream()->Add("}}");
   }
+
  private:
   bool first_;
   StringStream* stream() { return stream_; }
   StringStream* stream_;
 };
 
 
 class AttributePrinter {
  public:
   explicit AttributePrinter(DotPrinter* out)
@@ skipping 381 matching lines @@
                                      RegExpNode* on_success) {
   return ToNode(min(),
                 max(),
                 is_greedy(),
                 body(),
                 compiler,
                 on_success);
 }
 
 
+// Scoped object to keep track of how much we unroll quantifier loops in the
+// regexp graph generator.
+class RegExpExpansionLimiter {
+ public:
+  static const int kMaxExpansionFactor = 6;
+  RegExpExpansionLimiter(RegExpCompiler* compiler, int factor)
+      : compiler_(compiler),
+        saved_expansion_factor_(compiler->current_expansion_factor()),
+        ok_to_expand_(saved_expansion_factor_ <= kMaxExpansionFactor) {
+    ASSERT(factor > 0);
+    if (ok_to_expand_) {
+      if (factor > kMaxExpansionFactor) {
+        // Avoid integer overflow of the current expansion factor.
+        ok_to_expand_ = false;
+        compiler->set_current_expansion_factor(kMaxExpansionFactor + 1);
+      } else {
+        int new_factor = saved_expansion_factor_ * factor;
+        ok_to_expand_ = (new_factor <= kMaxExpansionFactor);
+        compiler->set_current_expansion_factor(new_factor);
+      }
+    }
+  }
+
+  ~RegExpExpansionLimiter() {
+    compiler_->set_current_expansion_factor(saved_expansion_factor_);
+  }
+
+  bool ok_to_expand() { return ok_to_expand_; }
+
+ private:
+  RegExpCompiler* compiler_;
+  int saved_expansion_factor_;
+  bool ok_to_expand_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(RegExpExpansionLimiter);
+};
+
+
 RegExpNode* RegExpQuantifier::ToNode(int min,
                                      int max,
                                      bool is_greedy,
                                      RegExpTree* body,
                                      RegExpCompiler* compiler,
                                      RegExpNode* on_success,
                                      bool not_at_start) {
   // x{f, t} becomes this:
   //
   //             (r++)<-.
@@ skipping 19 matching lines @@
   if (max == 0) return on_success;  // This can happen due to recursion.
   bool body_can_be_empty = (body->min_match() == 0);
   int body_start_reg = RegExpCompiler::kNoRegister;
   Interval capture_registers = body->CaptureRegisters();
   bool needs_capture_clearing = !capture_registers.is_empty();
   if (body_can_be_empty) {
     body_start_reg = compiler->AllocateRegister();
   } else if (FLAG_regexp_optimization && !needs_capture_clearing) {
     // Only unroll if there are no captures and the body can't be
     // empty.
-    if (min > 0 && min <= kMaxUnrolledMinMatches) {
-      int new_max = (max == kInfinity) ? max : max - min;
-      // Recurse once to get the loop or optional matches after the fixed ones.
-      RegExpNode* answer = ToNode(
-          0, new_max, is_greedy, body, compiler, on_success, true);
-      // Unroll the forced matches from 0 to min.  This can cause chains of
-      // TextNodes (which the parser does not generate).  These should be
-      // combined if it turns out they hinder good code generation.
-      for (int i = 0; i < min; i++) {
-        answer = body->ToNode(compiler, answer);
+    {
+      RegExpExpansionLimiter limiter(
+          compiler, min + ((max != min) ? 1 : 0));
+      if (min > 0 && min <= kMaxUnrolledMinMatches && limiter.ok_to_expand()) {
+        int new_max = (max == kInfinity) ? max : max - min;
+        // Recurse once to get the loop or optional matches after the fixed
+        // ones.
+        RegExpNode* answer = ToNode(
+            0, new_max, is_greedy, body, compiler, on_success, true);
+        // Unroll the forced matches from 0 to min.  This can cause chains of
+        // TextNodes (which the parser does not generate).  These should be
+        // combined if it turns out they hinder good code generation.
+        for (int i = 0; i < min; i++) {
+          answer = body->ToNode(compiler, answer);
+        }
+        return answer;
       }
-      return answer;
     }
-    if (max <= kMaxUnrolledMaxMatches) {
-      ASSERT(min == 0);
-      // Unroll the optional matches up to max.
-      RegExpNode* answer = on_success;
-      for (int i = 0; i < max; i++) {
-        ChoiceNode* alternation = new ChoiceNode(2);
-        if (is_greedy) {
-          alternation->AddAlternative(GuardedAlternative(body->ToNode(compiler,
-                                                                      answer)));
-          alternation->AddAlternative(GuardedAlternative(on_success));
-        } else {
-          alternation->AddAlternative(GuardedAlternative(on_success));
-          alternation->AddAlternative(GuardedAlternative(body->ToNode(compiler,
-                                                                      answer)));
+    if (max <= kMaxUnrolledMaxMatches && min == 0) {
+      ASSERT(max > 0);  // Due to the 'if' above.
+      RegExpExpansionLimiter limiter(compiler, max);
+      if (limiter.ok_to_expand()) {
+        // Unroll the optional matches up to max.
+        RegExpNode* answer = on_success;
+        for (int i = 0; i < max; i++) {
+          ChoiceNode* alternation = new ChoiceNode(2);
+          if (is_greedy) {
+            alternation->AddAlternative(
+                GuardedAlternative(body->ToNode(compiler, answer)));
+            alternation->AddAlternative(GuardedAlternative(on_success));
+          } else {
+            alternation->AddAlternative(GuardedAlternative(on_success));
+            alternation->AddAlternative(
+                GuardedAlternative(body->ToNode(compiler, answer)));
+          }
+          answer = alternation;
+          if (not_at_start) alternation->set_not_at_start();
         }
-        answer = alternation;
-        if (not_at_start) alternation->set_not_at_start();
+        return answer;
       }
-      return answer;
     }
   }
   bool has_min = min > 0;
   bool has_max = max < RegExpTree::kInfinity;
   bool needs_counter = has_min || has_max;
   int reg_ctr = needs_counter
       ? compiler->AllocateRegister()
       : RegExpCompiler::kNoRegister;
   LoopChoiceNode* center = new LoopChoiceNode(body->min_match() == 0);
   if (not_at_start) center->set_not_at_start();
@@ skipping 305 matching lines @@
     table.AddRange(base->at(i), CharacterRangeSplitter::kInBase);
   for (int i = 0; i < overlay.length(); i += 2) {
     table.AddRange(CharacterRange(overlay[i], overlay[i+1]),
                    CharacterRangeSplitter::kInOverlay);
   }
   CharacterRangeSplitter callback(included, excluded);
   table.ForEach(&callback);
 }
 
 
-static void AddUncanonicals(Isolate* isolate,
-                            ZoneList<CharacterRange>* ranges,
-                            int bottom,
-                            int top);
-
-
 void CharacterRange::AddCaseEquivalents(ZoneList<CharacterRange>* ranges,
                                         bool is_ascii) {
   Isolate* isolate = Isolate::Current();
   uc16 bottom = from();
   uc16 top = to();
   if (is_ascii) {
     if (bottom > String::kMaxAsciiCharCode) return;
     if (top > String::kMaxAsciiCharCode) top = String::kMaxAsciiCharCode;
   }
   unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
@@ skipping 140 matching lines @@
     result.SetElementsInSecondSet();
   } else if (j < range->length()) {
     // Argument range contains something not in word range.
     result.SetElementsInFirstSet();
   }
 
   return result;
 }
 
 
-static void AddUncanonicals(Isolate* isolate,
-                            ZoneList<CharacterRange>* ranges,
-                            int bottom,
-                            int top) {
-  unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
-  // Zones with no case mappings.  There is a DEBUG-mode loop to assert that
-  // this table is correct.
-  // 0x0600 - 0x0fff
-  // 0x1100 - 0x1cff
-  // 0x2000 - 0x20ff
-  // 0x2200 - 0x23ff
-  // 0x2500 - 0x2bff
-  // 0x2e00 - 0xa5ff
-  // 0xa800 - 0xfaff
-  // 0xfc00 - 0xfeff
-  const int boundary_count = 18;
-  int boundaries[] = {
-      0x600, 0x1000, 0x1100, 0x1d00, 0x2000, 0x2100, 0x2200, 0x2400, 0x2500,
-      0x2c00, 0x2e00, 0xa600, 0xa800, 0xfb00, 0xfc00, 0xff00};
-
-  // Special ASCII rule from spec can save us some work here.
-  if (bottom == 0x80 && top == 0xffff) return;
-
-  if (top <= boundaries[0]) {
-    CharacterRange range(bottom, top);
-    range.AddCaseEquivalents(ranges, false);
-    return;
-  }
-
-  // Split up very large ranges.  This helps remove ranges where there are no
-  // case mappings.
-  for (int i = 0; i < boundary_count; i++) {
-    if (bottom < boundaries[i] && top >= boundaries[i]) {
-      AddUncanonicals(isolate, ranges, bottom, boundaries[i] - 1);
-      AddUncanonicals(isolate, ranges, boundaries[i], top);
-      return;
-    }
-  }
-
-  // If we are completely in a zone with no case mappings then we are done.
-  for (int i = 0; i < boundary_count; i += 2) {
-    if (bottom >= boundaries[i] && top < boundaries[i + 1]) {
-#ifdef DEBUG
-      for (int j = bottom; j <= top; j++) {
-        unsigned current_char = j;
-        int length = isolate->jsregexp_uncanonicalize()->get(current_char,
-                                                             '\0', chars);
-        for (int k = 0; k < length; k++) {
-          ASSERT(chars[k] == current_char);
-        }
-      }
-#endif
-      return;
-    }
-  }
-
-  // Step through the range finding equivalent characters.
-  ZoneList<unibrow::uchar> *characters = new ZoneList<unibrow::uchar>(100);
-  for (int i = bottom; i <= top; i++) {
-    int length = isolate->jsregexp_uncanonicalize()->get(i, '\0', chars);
-    for (int j = 0; j < length; j++) {
-      uc32 chr = chars[j];
-      if (chr != i && (chr < bottom || chr > top)) {
-        characters->Add(chr);
-      }
-    }
-  }
-
-  // Step through the equivalent characters finding simple ranges and
-  // adding ranges to the character class.
-  if (characters->length() > 0) {
-    int new_from = characters->at(0);
-    int new_to = new_from;
-    for (int i = 1; i < characters->length(); i++) {
-      int chr = characters->at(i);
-      if (chr == new_to + 1) {
-        new_to++;
-      } else {
-        if (new_to == new_from) {
-          ranges->Add(CharacterRange::Singleton(new_from));
-        } else {
-          ranges->Add(CharacterRange(new_from, new_to));
-        }
-        new_from = new_to = chr;
-      }
-    }
-    if (new_to == new_from) {
-      ranges->Add(CharacterRange::Singleton(new_from));
-    } else {
-      ranges->Add(CharacterRange(new_from, new_to));
-    }
-  }
-}
-
-
 ZoneList<CharacterRange>* CharacterSet::ranges() {
   if (ranges_ == NULL) {
     ranges_ = new ZoneList<CharacterRange>(2);
     CharacterRange::AddClassEscape(standard_set_type_, ranges_);
   }
   return ranges_;
 }
 
 
 // Move a number of elements in a zonelist to another position
@@ skipping 979 matching lines @@
   }
 
   return compiler.Assemble(&macro_assembler,
                            node,
                            data->capture_count,
                            pattern);
 }
 
 
 }}  // namespace v8::internal