问在C语言中有8个翻译阶段的海报

EN

                       ANSI C translation phases
                       =========================

          +-------------------------------------------------+
          | map physical characters to source character set |
          |     replace line terminators with newlines      |
          |           decode trigraph sequences             |
          +-------------------------------------------------+
                                   |
                                   V
               +---------------------------------------+
               | join lines along trailing backslashes |
               +---------------------------------------+
                                   |
                                   V
     +-------------------------------------------------------------+
     | decompose into preprocessing tokens and whitespace/comments |
     |                      strip comments                         |
     |                      retain newlines                        |
     +-------------------------------------------------------------+        
                                   |
                                   V
          +------------------------------------------------+
          | execute preprocessing directives/invoke macros |
          |              process included files            |
          +------------------------------------------------+
                                   |
                                   V
   +----------------------------------------------------------------+
   | decode escape sequences in character constants/string literals |
   +----------------------------------------------------------------+
                                   |
                                   V
                +--------------------------------------+
                | concatenate adjacent string literals |
                +--------------------------------------+
                                   |
                                   V
              +------------------------------------------+
              | convert preprocessing tokens to C tokens |
              |       analyze and translate tokens       |
              +------------------------------------------+
                                   |
                                   V
                    +-----------------------------+
                    | resolve external references |
                    |        link libraries       |
                    |      build program image    |
                    +-----------------------------+

5.1.1.2 Translation phases

1 The precedence among the syntax rules of translation is specified by the following
phases. (*5)
    1. Physical source file multibyte characters are mapped, in an implementation
       defined manner, to the source character set (introducing new-line characters for
       end-of-line indicators) if necessary. Trigraph sequences are replaced by
       corresponding single-character internal representations.
    2. Each instance of a backslash character (\) immediately followed by a new-line
       character is deleted, splicing physical source lines to form logical source lines.
       Only the last backslash on any physical source line shall be eligible for being part
       of such a splice. A source file that is not empty shall end in a new-line character,
       which shall not be immediately preceded by a backslash character before any such
       splicing takes place.
    3. The source file is decomposed into preprocessing tokens (*6) and sequences of
       white-space characters (including comments). A source file shall not end in a
       partial preprocessing token or in a partial comment. Each comment is replaced by
       one space character. New-line characters are retained. Whether each nonempty
       sequence of white-space characters other than new-line is retained or replaced by
       one space character is implementation-defined.
    4. Preprocessing directives are executed, macro invocations are expanded, and
       _Pragma unary operator expressions are executed. If a character sequence that
       matches the syntax of a universal character name is produced by token
       concatenation (6.10.3.3), the behavior is undefined. A #include preprocessing
       directive causes the named header or source file to be processed from phase 1
       through phase 4, recursively. All preprocessing directives are then deleted.
    5. Each source character set member and escape sequence in character constants and
       string literals is converted to the corresponding member of the execution character
       set; if there is no corresponding member, it is converted to an implementation-defined
       member other than the null (wide) character. (*7)
    6. Adjacent string literal tokens are concatenated.
    7. White-space characters separating tokens are no longer significant. Each
       preprocessing token is converted into a token. The resulting tokens are
       syntactically and semantically analyzed and translated as a translation unit.
    8. All external object and function references are resolved. Library components are
       linked to satisfy external references to functions and objects not defined in the
       current translation. All such translator output is collected into a program image
       which contains information needed for execution in its execution environment.

(*5) Implementations shall behave as if these separate phases occur, even though many are typically folded
     together in practice. Source files, translation units, and translated translation units need not
     necessarily be stored as files, nor need there be any one-to-one correspondence between these entities
     and any external representation. The description is conceptual only, and does not specify any
     particular implementation.
(*6) Adjacent string literal tokens are concatenated.
(*7) White-space characters separating tokens are no longer significant. Each
     preprocessing token is converted into a token. The resulting tokens are
     syntactically and semantically analyzed and translated as a translation unit.