Phases of translation
The compiler processes a source file into an executable
in eight conceptual steps, which are called
phases of translation.
While some of these phases may actually be folded together,
the compiler behaves as if they occur separately, in sequence.
-
Trigraph sequences are replaced by their single-character equivalents.
Trigraph sequences are explained in
``Preprocessing''.
-
Any source lines that end with a backslash and new-line
are spliced together with the next line
by deleting the backslash and new-line.
-
The source file is partitioned into preprocessing
tokens and sequences of white-space characters.
Each comment is, in effect, replaced by one space character.
Preprocessing tokens are explained in
``Preprocessing''.
-
Preprocessing directives are executed, and macros are expanded.
Any files named in
#include
statements are processed from
phase 1 through phase 4, recursively.
-
Escape sequences in character constants
and string literals are converted to their character equivalents.
-
Adjacent character string literals,
and wide character string literals, are concatenated.
-
Each preprocessing token is converted into a token.
The resulting tokens are syntactically and semantically
analyzed and translated.
Tokens are explained in
``Source files and tokenization''.
-
All external object and function references are resolved.
Libraries are linked to satisfy external references not
defined in the current translation unit.
All translator output is collected into a program image
which contains information needed for execution.
Output from certain phases may be saved and examined
by specifying option flags on the
cc
command line.
The preprocessing token sequence resulting
from Phase 4 can be saved by using the following options:
-
-P
leaves preprocessed output in a file with a .i
extension.
-
-E
sends preprocessed output to the standard output.
Output from Phase 7 can be saved in a file with a .o
extension
by using the
-c
option to
cc.
The output of Phase 8 is the compilation system's final output
(a.out).
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Source files and tokenization
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Global behavior
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 27 April 2004