C程序的编译阶段是什么? - 代码日志







Are the stages of compilation of a C++ program specified by the standard?


C标准定义了9个“翻译阶段”。报价从the N3242 draft(10MB PDF),日期为2011-02-28(在官方C11标准发布之前),第2.2节:

The precedence among the syntax rules of translation is specified by the following phases [see footnote].

  1. Physical source file characters are mapped, in an implementation-defined manner, to the basic source character set
    (introducing new-line characters for end-of-line indicators) if
    necessary. [SNIP]
  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. [SNIP]
  3. The source file is decomposed into preprocessing tokens (2.5) and sequences of white-space characters (including comments). [SNIP]
  4. Preprocessing directives are executed, macro invocations are expanded, and _Pragma unary operator expressions are executed. [SNIP]
  5. Each source character set member in a character literal or a string literal, as well as each escape sequence and universal-character-name
    in a character literal or a non-raw string literal, is converted to
    the corresponding member of the execution character set; [SNIP]
  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. (2.7). The
    resulting tokens are syntactically and semantically analyzed and
    translated as a translation unit. [SNIP]
  8. Translated translation units and instantiation units are combined as follows: [SNIP]
  9. All external entity references are resolved. Library components are linked to satisfy external references to entities 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.

[footnote] Implementations must behave as if these separate phases occur, although in practice different phases might be folded together.