57 lines
1.7 KiB
Text
57 lines
1.7 KiB
Text
.NH
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Outline of the program
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.PP
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The program can be divided into three parts. A first pass, which
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parses C program files and outputs definitions, a second pass which
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processes the definitions and a driver,
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which feeds the set of files to the first pass and
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directs its output to the second pass. Both passes produce the
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warnings on standard error output, which are redirected to standard
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output by the driver.
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.PP
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The first pass is based on an existing C front end, called
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.I cem
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[3].
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.I Cem
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is part of the Amsterdam Compiler Kit (ACK), as described in [4].
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.PP
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Most of the code of
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.I cem
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is left unchanged. This has several reasons. A lot of work, which
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is done by
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.I cem
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, must also be done by
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.I lint.
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E.g. the lexical analysis, the macro expansions,
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the parsing part and the semantical analysis.
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Only the code generation part is turned off.
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An advantage of this approach is, that a person who understands
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.I cem
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will not have to spend to much time in understanding
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.I lint.
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.PP
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All changes and extensions to
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.I cem
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can be turned off by not defining the compiler directive
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.ft CW
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LINT.
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.R
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Compiling should then result in the original C compiler.
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.PP
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The second pass is a much less complex program.
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It reads simple definitions generated by the first pass and
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checks their consistency.
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This second pass gives warnings
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about wrong usage of function arguments, their results and
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about external variables, which are used and defined in more
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than one file.
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.PP
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The driver is a shell program, to be executed by the
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.UX
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shell
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.I sh.
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It executes the two passes and let them communicate through a
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filter (sort).
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Actually it is simplex communication: the first pass only talks to
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the second pass through the filter.
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.bp
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