source: project/wiki/Using the compiler @ 7273

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1[[tags: manual]]
4== Using the compiler
6The interface to {{chicken}} is intentionally simple.  System
7dependent makefiles, shell-scripts or batch-files should perform
8any necessary steps before and after invocation of {{chicken}}.
9A program named {{csc}} provides a much simpler
10interface to the Scheme- and C-compilers and linker. Enter
12 csc -help
14on the command line for more information.
16=== Compiler command line format
18 chicken FILENAME {OPTION}
20{{FILENAME}} is the complete pathname of the source file that is to
21be translated into C. A filename argument of {{-}} specifies that
22the source text should be read from standard input. Note that the filename
23has to be the first argument to {{chicken}}.
25Possible options are:
27; -analyze-only : Stop compilation after first analysis pass.
29; -benchmark-mode : Equivalent to {{-no-trace -no-lambda-info -optimize-level 3}} {{-fixnum-arithmetic -disable-interrupts -block -lambda-lift}}.
31; -block : Enable block-compilation. When this option is specified, the compiler assumes that global variables are not modified outside this compilation-unit.  Specifically, toplevel bindings are not seen by {{eval}} and unused toplevel bindings are removed.
33; -case-insensitive : Enables the reader to read symbols case insensitive. The default is to read case sensitive (in violation of R5RS).  This option registers the {{case-insensitive}} feature identifier.
35; -check-imports : Search for references to undefined global variables. For each library unit accessed via {{(declare (uses ...))}}, the compiler will search a file named {{UNITNAME.exports}} in the current include path and load its contents into the ''import-table'' (if found). Also, export-information for extensions (accessed through {{(require-extension ...)}}) will be searched and stored in the import-table. If a required extension does not provide explicit export-information a {{.exports}} file is searched (as with used units). After the analysis phase of the compiler, referenced toplevel variables for which no assignment was found will generate a warning. Also, re-assignments of imported variables will trigger a warning.
37; -check-syntax : Aborts compilation process after macro-expansion and syntax checks.
39; -debug MODES : Enables one or more compiler debugging modes. {{MODES}} is a string of characters that select debugging information about the compiler that will be printed to standard output.
41     t          show time needed for compilation
42     b          show breakdown of time needed for each compiler pass
43     o          show performed optimizations
44     r          show invocation parameters
45     s          show program-size information and other statistics
46     a          show node-matching during simplification
47     p          show execution of compiler sub-passes
48     l          show lambda-lifting information
49     m          show GC statistics during compilation
50     n          print the line-number database
51     c          print every expression before macro-expansion
52     u          lists all unassigned global variable references
53     x          display information about experimental features
54     D          when printing nodes, use node-tree output
55     N          show the real-name mapping table
56     U          show expressions after the secondary user pass
57     0          show database before lambda-lifting pass
58     L          show expressions after lambda-lifting
59     M          show unit-information and syntax-/runtime-requirements
60     1          show source expressions
61     2          show canonicalized expressions
62     3          show expressions converted into CPS
63     4          show database after each analysis pass
64     5          show expressions after each optimization pass
65     6          show expressions after each inlining pass
66     7          show expressions after complete optimization
67     8          show database after final analysis
68     9          show expressions after closure conversion
70; -debug-level LEVEL : Selects amount of debug-information. {{LEVEL}} should be an integer.
72     -debug-level 0             is equivalent to -no-trace -no-lambda-info
73     -debug-level 1             is equivalent to -no-trace
74     -debug-level 2             does nothing (the default)
76; -disable-interrupts : Equivalent to the {{(disable-interrupts)}} declaration. No interrupt-checks are generated for compiled programs.
78; -disable-compiler-macros : disable expansion of compiler macros.
80; -disable-stack-overflow-checks : Disables detection of stack overflows. This is equivalent to running the compiled executable with the {{-:o}} runtime option.
82; -disable-warning CLASS : Disables specific class of warnings, may be given multiple times. The following classes are defined:
84     usage              warnings related to command-line arguments
85     type               warnings related to type-conversion
86     ext                warnings related to extension libraries
87     var                warnings related to variable- and syntax-definitions and use
88     const              warnings related to constant-definitions
89     syntax             syntax-related warnings
90     redef              warnings about redefinitions of standard- or extended-bindings
91     call               warnings related to known procedure calls
92     ffi                warnings related to the foreign function interface
94; -dynamic : This option should be used when compiling files intended to be loaded dynamically into a running Scheme program.
96; -epilogue FILENAME : Includes the file named {{FILENAME}} at the end of the compiled source file. The include-path is not searched. This option may be given multiple times.
98; -emit-exports FILENAME : Write exported toplevel variables to {{FILENAME}}.
100; -emit-external-prototypes-first : Emit prototypes for callbacks defined with {{define-external}} before any other foreign declarations. This is sometimes useful, when C/C++ code embedded into the a Scheme program has to access the callbacks. By default the prototypes are emitted after foreign declarations.
102; -explicit-use : Disables automatic use of the units {{library, eval}} and {{extras}}. Use this option if compiling a library unit instead of an application unit.
104; -extend FILENAME : Loads a Scheme source file or compiled Scheme program (on systems that support it) before compilation commences. This feature can be used to extend the compiler.  This option may be given multiple times. The file is also searched in the current include path and in the extension-repository.
106; -extension : Mostly equivalent to {{-prelude '(define-extension <NAME>)'}}, where {{<NAME>}} is the basename of the currently compiled file. Note that if you want to compile a file as a normal (dynamically loadable) extension library, you should also pass the {{-shared}} option.
108; -feature SYMBOL : Registers {{SYMBOL}} to be a valid feature identifier for {{cond-expand}}. Multiple symbols may be given, if comma-separated.
110; -fixnum-arithmetic : Equivalent to {{(fixnum-arithmetic)}} declaration. Assume all mathematical operations use small integer arguments.
112; -heap-size NUMBER : Sets a fixed heap size of the generated executable to {{NUMBER}} bytes. The parameter may be followed by a  {{M}} ({{m}}) or {{K}} ({{k}}) suffix which stand for mega- and kilobytes, respectively.  The default heap size is 5 kilobytes. Note that only half of it is in use at every given time.
114; -heap-initial-size NUMBER : Sets the size that the heap of the compiled application should have at startup time.
116; -heap-growth PERCENTAGE : Sets the heap-growth rate for the compiled program at compile time (see: {{-:hg}}).
118; -heap-shrinkage PERCENTAGE : Sets the heap-shrinkage rate for the compiled program at compile time (see: {{-:hs}}).
120; -help : Print a summary of available options and the format of the command line parameters and exit the compiler.
122; -import FILENAME : Read exports from linked or loaded libraries from given file. See also {{-check-imports}}. This is equivalent to declaring {{(declare (import FILENAME))}}. Implies {{-check-imports}}.
124; -include-path PATHNAME : Specifies an additional search path for files included via the {{include}} special form. This option may be given multiple times. If the environment variable {{CHICKEN_INCLUDE_PATH}} is set, it should contain a list of alternative include pathnames separated by {{;}}.
126; -inline : Enable procedure inlining for known procedures of a size below the threshold (which can be set through the {{-inline-limit}} option).
128; -inline-limit THRESHOLD : Sets the maximum size of a potentially inlinable procedure. The default threshold is {{10}}.
130; -keyword-style STYLE : Enables alternative keyword syntax, where {{STYLE}} may be either {{prefix}} (as in Common Lisp), {{suffix}} (as in DSSSL) or {{none}}. Any other value is ignored. The default is {{suffix}}.
132; -keep-shadowed-macros : Do not remove macro definitions with the same name as assigned toplevel variables (the default is to remove the macro definition).
134; -lambda-lift : Enable the optimization known as lambda-lifting.
136; -no-lambda-info : Don't emit additional information for each {{lambda}} expression (currently the argument-list, after alpha-conversion/renaming).
138; -no-trace : Disable generation of tracing information. If a compiled executable should halt due to a runtime error, then a list of the name and the line-number (if available) of the last procedure calls is printed, unless {{-no-trace}} is specified. With this option the generated code is slightly faster.
140; -no-warnings : Disable generation of compiler warnings.
142; -nursery NUMBER :
143; -stack-size NUMBER : Sets the size of the first heap-generation of the generated executable to {{NUMBER}} bytes. The parameter may be followed by a {{M}} ({{m}}) or {{K}} ({{k}}) suffix.  The default stack-size depends on the target platform.
145; -optimize-leaf-routines : Enable leaf routine optimization.
147; -optimize-level LEVEL : Enables certain sets of optimization options. {{LEVEL}} should be an integer.
149     -optimize-level 0          does nothing.
150     -optimize-level 1          is equivalent to -optimize-leaf-routines
151     -optimize-level 2          is currently the same as -optimize-level 1
152     -optimize-level 3          is equivalent to -optimize-leaf-routines -unsafe
154; -output-file FILENAME : Specifies the pathname of the generated C file. Default is {{FILENAME.c}}.
156; -postlude EXPRESSIONS : Add {{EXPRESSIONS}} after all other toplevel expressions in the compiled file.  This option may be given multiple times. Processing of this option takes place after processing of {{-epilogue}}.
158; -prelude EXPRESSIONS : Add {{EXPRESSIONS}} before all other toplevel expressions in the compiled file.  This option may be given multiple times. Processing of this option takes place before processing of {{-prologue}}.
160; -profile :
161;-accumulate-profile : Instruments the source code to count procedure calls and execution times. After the program terminates (either via an explicit {{exit}} or implicitly), profiling statistics are written to a file named {{PROFILE}}. Each line of the generated file contains a list with the procedure name, the number of calls and the time spent executing it. Use the {{chicken-profile}} program to display the profiling information in a more user-friendly form. Enter {{chicken-profile}} with no arguments at the command line to get a list of available options. The {{-accumulate-profile}} option is similar to {{-profile}}, but the resulting profile information will be appended to any existing {{PROFILE}} file. {{chicken-profile}} will merge and sum up the accumulated timing information, if several entries for the same procedure calls exist.
163; -profile-name FILENAME : Specifies name of the generated profile information (which defaults to {{PROFILE}}. Implies {{-profile}}.
165; -prologue FILENAME : Includes the file named {{FILENAME}} at the start of the compiled source file.  The include-path is not searched. This option may be given multiple times.
167; -quiet : Disables output of compile information.
169; -raw : Disables the generation of any implicit code that uses the Scheme libraries (that is all runtime system files besides {{runtime.c}} and {{chicken.h}}).
171; -require-extension NAME : Loads the extension {{NAME}} before the compilation process commences. This is identical to adding {{(require-extension NAME)}} at the start of the compiled program. If {{-uses NAME}} is also given on the command line, then any occurrences of {{-require-extension NAME}} are replaced with {{(declare (uses NAME))}}. Multiple names may be given and should be separated by {{,}}.
173; -run-time-macros : Makes macros also available at run-time. By default macros are not available at run-time.
175; -to-stdout : Write compiled code to standard output instead of creating a {{.c}} file.
177; -unit NAME : Compile this file as a library unit. Equivalent to {{-prelude "(declare (unit NAME))"}}
179; -unsafe : Disable runtime safety checks.
181; -unsafe-libraries : Marks the generated file for being linked with the unsafe runtime system. This should be used when generating shared object files that are to be loaded dynamically. If the marker is present, any attempt to load code compiled with this option will signal an error.
183; -uses NAME : Use definitions from the library unit {{NAME}}. This is equivalent to {{-prelude "(declare (uses NAME))"}}. Multiple arguments may be given, separated by {{,}}.
185; -no-usual-integrations : Specifies that standard procedures and certain internal procedures may be redefined, and can not be inlined. This is equivalent to declaring {{(not usual-integrations)}}.
187; -version : Prints the version and some copyright information and exit the compiler.
189; -verbose : Prints progress information to standard output during compilation.
191The environment variable {{CHICKEN_OPTIONS}} can be set to a string
192with default command-line options for the compiler.
194=== Runtime options
196After successful compilation a C source file is generated and can be
197compiled with a C compiler. Executables generated with CHICKEN (and the
198compiler itself) accept a small set of runtime options:
200; {{-:?}} : Shows a list of the available runtime options and exits the program.
202; {{-:aNUMBER}} : Specifies the length of the buffer for recording a trace of the last invoked procedures. Defaults to 16.
204; {{-:b}} : Enter a read-eval-print-loop when an error is encountered.
206; {{-:B}} : Sounds a bell (ASCII 7) on every major garbage collection.
208; {{-:c}} : Forces console mode. Currently this is only used in the interpreter ({{csi}}) to force output of the {{#;N>}} prompt even if stdin is not a terminal (for example if running in an {{emacs}} buffer under Windows).
210; {{-:d}} : Prints some debug-information at runtime.
212; {{-:D}} : Prints some more debug-information at runtime.
214; {{-:fNUMBER}} : Specifies the maximal number of currently pending finalizers before finalization is forced.
216; {{-:hNUMBER}} : Specifies fixed heap size
218; {{-:hgPERCENTAGE}} : Sets the growth rate of the heap in percent. If the heap is exhausted, then it will grow by {{PERCENTAGE}}. The default is 200.
220; {{-:hiNUMBER}} : Specifies the initial heap size
222; {{-:hmNUMBER}} : Specifies a maximal heap size. The default is (2GB - 15).
224; {{-:hsPERCENTAGE}} : Sets the shrink rate of the heap in percent. If no more than a quarter of {{PERCENTAGE}} of the heap is used, then it will shrink to {{PERCENTAGE}}. The default is 50.  Note: If you want to make sure that the heap never shrinks, specify a value of {{0}}.  (this can be useful in situations where an optimal heap-size is known in advance).
226; {{-:o}} : Disables detection of stack overflows at run-time.
228; {{-:r}} : Writes trace output to stderr. This option has no effect with in files compiled with the {{-no-trace}} options.
230; {{-:sNUMBER}} : Specifies stack size.
232; {{-:tNUMBER}} : Specifies symbol table size.
234; {{-:w}} : Enables garbage collection of unused symbols. By default unused and unbound symbols are not garbage collected.
236; {{-:x}} : Raises uncaught exceptions of separately spawned threads in primordial thread. By default uncaught exceptions in separate threads are not handled, unless the primordial one explicitly joins them. When warnings are enabled (the default) and {{-:x}} is not given, a warning will be shown, though.
238The argument values may be given in bytes, in kilobytes (suffixed with
239{{K}} or {{k}}), in megabytes (suffixed with {{M}}
240or {{m}}), or in gigabytes (suffixed with {{G}}
241or {{g}}). Runtime options may be combined, like {{-:dc}},
242but everything following a {{NUMBER}} argument is ignored. So
243{{-:wh64m}} is OK, but {{-:h64mw}} will not enable GC of
244unused symbols.
245=== Examples
247==== A simple example (with one source file)
249To compile a Scheme program (assuming a UNIX-like environment) consisting of a single source file, perform the following steps.
251===== Writing your source file
253In this example we will assume your source file is called {{foo.scm}}:
255<enscript highlight=scheme>
256;;; foo.scm
258(define (fac n)
259  (if (zero? n)
260      1
261      (* n (fac (- n 1))) ) )
263(write (fac 10))
267===== Compiling your program
269Compile the file {{foo.scm}}:
271 % csc foo.scm
273This will produce the {{foo}} executable:
275 % ls
276 foo  foo.scm
278===== Running your program
280To run your newly compiled executable use:
282 % foo
283 3628800
285If you get a {{foo: command not found}} error, you might want to try with {{./foo}} instead
286(or, in Unix machines, modify your {{PATH}} environment variable to include your current directory).
287==== An example with multiple files
289If multiple bodies of Scheme code are to be combined into a single
290executable, then we have to compile each file and link the resulting
291object files together with the runtime system.
293Let's consider an example where your program consists of multiple source files.
295===== Writing your source files
297The declarations in these files specify which of the compiled files is the main
298module, and which is the library module. An executable can only have
299one main module, since a program has only a single entry-point. In this
300case {{foo.scm}} is the main module, because it doesn't have a
301{{unit}} declaration:
303<enscript highlight=scheme>
304;;; foo.scm
306; The declaration marks this source file as dependant on the symbols provided
307; by the bar unit:
308(declare (uses bar))
310(write (fac 10)) (newline)
313{{bar.scm}} will be our library:
315<enscript highlight=scheme>
316;;; bar.scm
318; The declaration marks this source file as the bar unit.  The names of the
319; units and your files don't need to match.
320(declare (unit bar))
322(define (fac n)
323  (if (zero? n)
324      1
325      (* n (fac (- n 1))) ) )
328===== Compiling and running your program
330You should compile your two files with the following commands:
332 % csc -c bar.scm
333 % csc -c foo.scm
335That should produce two files, {{bar.o}} and {{foo.o}}.
336They contain the code from your source files in compiled form.
338To link your compiled files use the following command:
340 % csc foo.o bar.o -o foo
342This should produce the {{foo}} executable, which you can run just as in the previous example.
343At this point you can also erase the {{*.o}} files.
345You could avoid one step and link the two files just as {{foo.scm}} is compiled:
347 % csc -c bar.scm
348 % csc foo.scm bar.o -o foo
350Note that if you want to distribute your program, you might want it to
351follow the GNU Coding Standards.  One relatively easy way to achieve
352this is to use Autoconf and Automake, two tools made for this specific
355=== Extending the compiler
357The compiler supplies a couple of hooks to add user-level passes to the
358compilation process. Before compilation commences any Scheme source files
359or compiled code specified using the {{-extend}} option are loaded
360and evaluated.  The parameters {{user-options-pass, user-read-pass,
361user-preprocessor-pass, user-pass, user-pass-2}} and {{user-post-analysis-pass}} can be set
362to procedures that are called to perform certain compilation passes
363instead of the usual processing (for more information about parameters
364see: [[Supported language]].
366; [parameter] user-options-pass : Holds a procedure that will be called with a list of command-line arguments and should return two values: the source filename and the actual list of options, where compiler switches have their leading {{-}} (hyphen) removed and are converted to symbols.  Note that this parameter is invoked '''before''' processing of the {{-extend}} option, and so can only be changed in compiled user passes.
368; [parameter] user-read-pass : Holds a procedure of three arguments. The first argument is a list of strings with the code passed to the compiler via {{-prelude}} options. The second argument is a list of source files including any files specified by {{-prologue}} and {{-epilogue}}. The third argument is a list of strings specified using {{-postlude}} options. The procedure should return a list of toplevel Scheme expressions.
370; [parameter] user-preprocessor-pass : Holds a procedure of one argument. This procedure is applied to each toplevel expression in the source file '''before''' macro-expansion. The result is macro-expanded and compiled in place of the original expression.
372; [parameter] user-pass : Holds a procedure of one argument. This procedure is applied to each toplevel expression '''after''' macro-expansion.  The result of the procedure is then compiled in place of the original expression.
374; [parameter] user-pass-2 : Holds a procedure of three arguments, which is called with the canonicalized node-graph as its sole argument. The result is ignored, so this pass has to mutate the node-structure to cause any effect.
376; [parameter] user-post-analysis-pass : Holds a procedure that will be called after every performed program analysis pass. The procedure (when defined) will be called with seven arguments: a symbol indicating the analysis pass, the program database, the current node graph, a getter and a setter-procedure which can be used to access and manipulate the program database, which holds various information about the compiled program, a pass iteration count, and an analysis continuation flag. The getter procedure should be called with two arguments: a symbol representing the binding for which information should be retrieved, and a symbol that specifies the database-entry. The current value of the database entry will be returned or {{#f}}, if no such entry is available. The setter procedure is called with three arguments: the symbol and key and the new value. The pass iteration count currently is meaningful only for the 'opt pass. The analysis continuation flag will be {{#f}} for the last 'opt pass. For information about the contents of the program database contact the author.
378Loaded code (via the {{-extend}} option) has access to the library
379units {{extras, srfi-1, srfi-4, utils, regex}} and the pattern matching macros.
380Multithreading is not available.
382Note that the macroexpansion/canonicalization phase of the compiler adds
383certain forms to the source program.  These extra expressions are not
384seen by {{user-preprocessor-pass}} but by {{user-pass}}.
386=== Distributing compiled C files
388It is relatively easy to create distributions of Scheme projects that
389have been compiled to C.  The runtime system of CHICKEN consists of only
390two handcoded C files ({{runtime.c}} and {{chicken.h}}), plus
391the file {{chicken-config.h}}, which is generated by the build process. All
392other modules of the runtime system and the extension libraries are just
393compiled Scheme code. The following example shows a minimal application, which
394should run without changes on the most frequent operating systems, like Windows,
395Linux or FreeBSD:
397Let's take a simple example.
399<enscript highlight=scheme>
400; hello.scm
402(print "Hello, world!")
405  % chicken hello.scm -optimize-level 3 -output-file hello.c
407Compiled to C, we get {{hello.c}}. We need the files {{chicken.h}} and
408{{runtime.c}}, which contain the basic runtime system, plus the three
409basic library files {{library.c}}, {{eval.c}} and {{extras.c}} which
410contain the same functionality as the library linked into a plain
411CHICKEN-compiled application, or which is available by default in the
412interpreter, {{csi}}:
414  % cd /tmp
415  %echo '(print "Hello World.")' > hello.scm
416  % cp $CHICKEN_BUILD/runtime.c .
417  % cp $CHICKEN_BUILD/library.c .
418  % cp $CHICKEN_BUILD/eval.c    .
419  % cp $CHICKEN_BUILD/extras.c  .
420  % gcc -static -Os -fomit-frame-pointer runtime.c library.c eval.c \
421    extras.c hello.c -o hello -lm
423Now we have all files together, and can create an tarball containing all the files:
425 % tar cf hello.tar Makefile hello.c runtime.c library.c eval.c extras.c chicken.h
426 % gzip hello.tar
428This is naturally rather simplistic. Things like enabling dynamic loading, estimating
429the optimal stack-size and selecting supported features of the host system would need
430more configuration- and build-time support. All this can be addressed using more
431elaborate build-scripts, makefiles or by using autoconf/automake.
433Note also that the size of the application can still be reduced by removing {{extras}} and
434{{eval}} and compiling {{hello.scm}} with the {{-explicit-use}} option.
436For more information, study the CHICKEN source code and/or get in
437contact with the author.
439Previous: [[The User's Manual]]
441Next: [[Using the interpreter]]
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