diff --git a/lib/rdoc/parser/c.rb b/lib/rdoc/parser/c.rb
index fd336f5f5b..6c2a47fff0 100644
--- a/lib/rdoc/parser/c.rb
+++ b/lib/rdoc/parser/c.rb
@@ -605,18 +605,46 @@ def find_attr_comment var_name, attr_name, read = nil, write = nil
     RDoc::Comment.new comment, @top_level
   end
 
+  ##
+  # Generate a Ruby-method table
+
+  def gen_body_table file_content
+    table = {}
+    file_content.scan(%r{
+      ((?>/\*.*?\*/\s*)?)
+      ((?:(?:\w+)\s+)?
+        (?:intern\s+)?VALUE\s+(\w+)
+        \s*(?:\([^)]*\))(?:[^;]|$))
+    | ((?>/\*.*?\*/\s*))^\s*(\#\s*define\s+(\w+)\s+(\w+))
+    | ^\s*\#\s*define\s+(\w+)\s+(\w+)
+    }xm) do
+      case
+      when $1
+        table[$3] = [:func_def, $1, $2, $~.offset(2)] if !table[$3] || table[$3][0] != :func_def
+      when $4
+        table[$6] = [:macro_def, $4, $5, $~.offset(5), $7] if !table[$6] || table[$6][0] == :macro_alias
+      when $8
+        table[$8] ||= [:macro_alias, $9]
+      end
+    end
+    table
+  end
+
   ##
   # Find the C code corresponding to a Ruby method
 
   def find_body class_name, meth_name, meth_obj, file_content, quiet = false
-    case file_content
-    when %r%((?>/\*.*?\*/\s*)?)
-            ((?:(?:\w+)\s+)?
-             (?:intern\s+)?VALUE\s+#{meth_name}
-             \s*(\([^)]*\))([^;]|$))%xm then
-      comment = RDoc::Comment.new $1, @top_level
-      body = $2
-      offset, = $~.offset(2)
+    if file_content
+      @body_table ||= {}
+      @body_table[file_content] ||= gen_body_table file_content
+      type, *args = @body_table[file_content][meth_name]
+    end
+
+    case type
+    when :func_def
+      comment = RDoc::Comment.new args[0], @top_level
+      body = args[1]
+      offset, = args[2]
 
       comment.remove_private if comment
 
@@ -645,12 +673,12 @@ def find_body class_name, meth_name, meth_obj, file_content, quiet = false
       meth_obj.line    = file_content[0, offset].count("\n") + 1
 
       body
-    when %r%((?>/\*.*?\*/\s*))^\s*(\#\s*define\s+#{meth_name}\s+(\w+))%m then
-      comment = RDoc::Comment.new $1, @top_level
-      body = $2
-      offset = $~.offset(2).first
+    when :macro_def
+      comment = RDoc::Comment.new args[0], @top_level
+      body = args[1]
+      offset, = args[2]
 
-      find_body class_name, $3, meth_obj, file_content, true
+      find_body class_name, args[3], meth_obj, file_content, true
 
       comment.normalize
       find_modifiers comment, meth_obj
@@ -664,11 +692,11 @@ def find_body class_name, meth_name, meth_obj, file_content, quiet = false
       meth_obj.line    = file_content[0, offset].count("\n") + 1
 
       body
-    when %r%^\s*\#\s*define\s+#{meth_name}\s+(\w+)%m then
+    when :macro_alias
       # with no comment we hope the aliased definition has it and use it's
       # definition
 
-      body = find_body(class_name, $1, meth_obj, file_content, true)
+      body = find_body(class_name, args[0], meth_obj, file_content, true)
 
       return body if body
 
@@ -763,28 +791,42 @@ def find_class_comment class_name, class_mod
     class_mod.add_comment comment, @top_level
   end
 
+  ##
+  # Generate a const table
+
+  def gen_const_table file_content
+    table = {}
+    @content.scan(%r{
+      ((?>^\s*/\*.*?\*/\s+))
+        rb_define_(\w+)\((?:\s*(?:\w+),)?\s*
+                           "(\w+)"\s*,
+                           .*?\)\s*;
+    | Document-(?:const|global|variable):\s
+        ((?:\w+::)*\w+)
+        \s*?\n((?>.*?\*/))
+    }mxi) do
+      case
+      when $1 then table[[$2, $3]] = $1
+      when $4 then table[$4] = "/*\n" + $5
+      end
+    end
+    table
+  end
+
   ##
   # Finds a comment matching +type+ and +const_name+ either above the
   # comment or in the matching Document- section.
 
   def find_const_comment(type, const_name, class_name = nil)
-    comment = if @content =~ %r%((?>^\s*/\*.*?\*/\s+))
-                             rb_define_#{type}\((?:\s*(\w+),)?\s*
-                                                "#{const_name}"\s*,
-                                                .*?\)\s*;%xmi then
-                $1
-              elsif class_name and
-                    @content =~ %r%Document-(?:const|global|variable):\s
-                                   #{class_name}::#{const_name}
-                                   \s*?\n((?>.*?\*/))%xm then
-                "/*\n#{$1}"
-              elsif @content =~ %r%Document-(?:const|global|variable):
-                                   \s#{const_name}
-                                   \s*?\n((?>.*?\*/))%xm then
-                "/*\n#{$1}"
-              else
-                ''
-              end
+    @const_table ||= {}
+    @const_table[@content] ||= gen_const_table @content
+    table = @const_table[@content]
+
+    comment =
+      table[[type, const_name]] ||
+      (class_name && table[class_name + "::" + const_name]) ||
+      table[const_name] ||
+      ''
 
     RDoc::Comment.new comment, @top_level
   end
diff --git a/lib/rdoc/parser/changelog.rb b/lib/rdoc/parser/changelog.rb
index a3567c1f81..60adeb88b9 100644
--- a/lib/rdoc/parser/changelog.rb
+++ b/lib/rdoc/parser/changelog.rb
@@ -101,9 +101,11 @@ def create_items items
   # Groups +entries+ by date.
 
   def group_entries entries
+    @time_cache ||= {}
     entries.group_by do |title, _|
       begin
-        Time.parse(title).strftime '%Y-%m-%d'
+        time = @time_cache[title]
+        (time || Time.parse(title)).strftime '%Y-%m-%d'
       rescue NoMethodError, ArgumentError
         time, = title.split '  ', 2
         Time.parse(time).strftime '%Y-%m-%d'
@@ -127,6 +129,7 @@ def group_entries entries
   #        'README.EXT.ja:  ditto']]
 
   def parse_entries
+    @time_cache ||= {}
     entries = []
     entry_name = nil
     entry_body = []
@@ -142,6 +145,7 @@ def parse_entries
 
         begin
           time = Time.parse entry_name
+          @time_cache[entry_name] = time
           # HACK Ruby 1.8 does not raise ArgumentError for Time.parse "Other"
           entry_name = nil unless entry_name =~ /#{time.year}/
         rescue NoMethodError
@@ -184,6 +188,7 @@ def parse_entries
   # Converts the ChangeLog into an RDoc::Markup::Document
 
   def scan
+    @time_cache = {}
     entries = parse_entries
     grouped_entries = group_entries entries
 
diff --git a/lib/rdoc/ruby_lex.rb b/lib/rdoc/ruby_lex.rb
index 91b90ab2cf..d56e693a3d 100644
--- a/lib/rdoc/ruby_lex.rb
+++ b/lib/rdoc/ruby_lex.rb
@@ -101,10 +101,10 @@ def initialize(content, options)
     @exp_line_no = @line_no = 1
     @here_readed = []
     @readed = []
+    @current_readed = @readed
     @rests = []
     @seek = 0
 
-    @here_header = false
     @indent = 0
     @indent_stack = []
     @lex_state = :EXPR_BEG
@@ -160,7 +160,7 @@ def get_readed
     end
 
     readed = @readed.join("")
-    @readed = []
+    @readed.clear
     readed
   end
 
@@ -170,13 +170,9 @@ def getc
       @rests.push nil unless buf_input
     end
     c = @rests.shift
-    if @here_header
-      @here_readed.push c
-    else
-      @readed.push c
-    end
+    @current_readed.push c
     @seek += 1
-    if c == "\n"
+    if c == "\n".freeze
       @line_no += 1
       @char_no = 0
     else
@@ -282,7 +278,7 @@ def initialize_input
     @indent_stack = []
     @lex_state = :EXPR_BEG
     @space_seen = false
-    @here_header = false
+    @current_readed = @readed
 
     @continue = false
     prompt
@@ -461,8 +457,8 @@ def lex_init()
           @indent_stack.pop
         end
       end
-      @here_header = false
-      @here_readed = []
+      @current_readed = @readed
+      @here_readed.clear
       Token(TkNL)
     end
 
@@ -1020,7 +1016,7 @@ def identify_here_document
       doc = '"'
     end
 
-    @here_header = false
+    @current_readed = @readed
     while l = gets
       l = l.sub(/(:?\r)?\n\z/, "\n")
       if (indent ? l.strip : l.chomp) == quoted
@@ -1037,7 +1033,7 @@ def identify_here_document
       doc << '"'
     end
 
-    @here_header = true
+    @current_readed = @here_readed
     @here_readed.concat reserve
     while ch = reserve.pop
       ungetc ch