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Commit bc65b5ec by Tom Tromey Committed by Tom Tromey
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gcj.texi: New file. 

	* gcj.texi: New file.
	* Make-lang.in ($(srcdir)/java/gcj.info): New target.
	(java.info): Depend on gcj.info.
	(java/gcj.dvi): New target.
	(java.dvi): Depend on gcj.dvi.
	(java.install-info): Wrote.

From-SVN: r39101
parent 988144ce
Showing with 521 additions and 2 deletions
gcc/java/.cvsignore
parse.c parse.c
parse-scan.c parse-scan.c
gcj.info*
gcc/java/ChangeLog
2001-01-17 Tom Tromey <tromey@redhat.com>
* gcj.texi: New file.
* Make-lang.in ($(srcdir)/java/gcj.info): New target.
(java.info): Depend on gcj.info.
(java/gcj.dvi): New target.
(java.dvi): Depend on gcj.dvi.
(java.install-info): Wrote.
2001-01-16 Jeff Sturm <jeff.sturm@appnet.com> 2001-01-16 Jeff Sturm <jeff.sturm@appnet.com>
* expr.c (java_lang_expand_expr): Use TREE_SYMBOL_REFERENCED after * expr.c (java_lang_expand_expr): Use TREE_SYMBOL_REFERENCED after
......
gcc/java/Make-lang.in
...@@ -145,8 +145,8 @@ java.all.cross: $(GCJ)-cross$(exeext) ...@@ -145,8 +145,8 @@ java.all.cross: $(GCJ)-cross$(exeext)
java.start.encap: $(GCJ)$(exeext) java.start.encap: $(GCJ)$(exeext)
java.rest.encap: java.rest.encap:
java.info: java.info: $(srcdir)/java/gcj.info
java.dvi: java.dvi: java/gcj.dvi
# Install hooks: # Install hooks:
# jc1, gcj, jvgenmain, and gcjh are installed elsewhere as part # jc1, gcj, jvgenmain, and gcjh are installed elsewhere as part
...@@ -182,6 +182,21 @@ java.uninstall: ...@@ -182,6 +182,21 @@ java.uninstall:
-rm -rf $(bindir)/$(JAVA_CROSS_NAME)$(exeext) -rm -rf $(bindir)/$(JAVA_CROSS_NAME)$(exeext)
java.install-info: java.install-info:
if [ -f jc1$(exeext) ] ; then \
if [ -f $(srcdir)/java/gcj.info ]; then \
rm -f $(infodir)/gcj.info*; \
for f in $(srcdir)/java/gcj.info*; do \
realfile=`echo $$f | sed -e 's|.*/\([^/]*\)$$|\1|'`; \
$(INSTALL_DATA) $$f $(infodir)/$$realfile; \
done; \
chmod a-x $(infodir)/gcj.info*; \
else true; fi; \
else true; fi
-if [ -f jc1$(exeext) ] && [ -f $(infodir)/gcj.info ]; then \
if $(SHELL) -c 'install-info --version' >/dev/null 2>&1; then \
install-info --dir-file=$(infodir)/dir $(infodir)/gcj.info; \
else true; fi; \
else true; fi
# #
# Clean hooks: # Clean hooks:
...@@ -274,3 +289,14 @@ java/jcf-path.o: java/jcf-path.c $(CONFIG_H) system.h java/jcf.h ...@@ -274,3 +289,14 @@ java/jcf-path.o: java/jcf-path.c $(CONFIG_H) system.h java/jcf.h
-DLIBGCJ_ZIP_FILE='"$(prefix)/share/libgcj.jar"' \ -DLIBGCJ_ZIP_FILE='"$(prefix)/share/libgcj.jar"' \
$(srcdir)/java/jcf-path.c $(OUTPUT_OPTION) $(srcdir)/java/jcf-path.c $(OUTPUT_OPTION)
# Documentation
$(srcdir)/java/gcj.info: $(srcdir)/java/gcj.texi
if test "x$(BUILD_INFO)" = xinfo; then \
rm -f $(srcdir)/java/gcc.info*; \
cd $(srcdir)/java && $(MAKEINFO) -o gcj.info gcj.texi; \
else true; fi
java/gcj.dvi: $(srcdir)/java/gcj.texi
TEXINPUTS=${texidir}:$(srcdir)/java:$$TEXINPUTS tex gcj.texi
texindex gcj.??
TEXINPUTS=${texidir}:$(srcdir)/java:$$TEXINPUTS tex gcj.texi
gcc/java/gcj.texi 0 → 100644
@\input texinfo @c -*-texinfo-*-
@setfilename gcj.info
@settitle Guide to GNU gcj
@c Note: When reading this manual you'll find lots of strange
@c circumlocutions like ``compiler for the Java language''.
@c This is necessary due to Sun's restrictions on the use of
@c the word ``Java'.
@ifinfo
@format
@dircategory Programming
@direntry
* Gcj: (gcj). Ahead-of-time compiler for the Java language
@end direntry
@dircategory Individual utilities
@direntry
* gcjh: (gcj)Invoking gcjh.
Generate header files from Java class files
* jv-scan: (gcj)Invoking jv-scan.
Print information about Java source files
* jcf-dump: (gcj)Invoking jcf-dump.
Print information about Java class files
* gij: (gcj)Invoking gij. GNU interpreter for Java bytecode
@end direntry
@end format
@end ifinfo
@titlepage
@title GNU gcj
@author Tom Tromey
@end titlepage
@node Top
@top Introduction
This manual describes how to use @code{gcj}, the GNU compiler for the
Java programming language. @code{gcj} can generate both @file{.class}
files and object files, and it can read both Java source code and
@file{.class} files.
@menu
* Invoking gcj:: Compiler options supported by @code{gcj}
* Compatibility:: Compatibility between gcj and other tools for Java
* Invoking gcjh:: Generate header files from class files
* Invoking jv-scan:: Print information about source files
* Invoking jcf-dump:: Print information about class files
* Invoking gij:: Interpreting Java bytecodes
* Resources:: Where to look for more information
@end menu
@node Invoking gcj
@chapter Invoking gcj
As @code{gcj} is just another front end to @code{gcc}, it supports many
of the same options as gcc. @xref{Option Summary, , Option Summary,
gcc, Using the GNU Compiler Collection}. This manual only documents the
options specific to @code{gcj}.
@menu
* Input Options:: How to find input files
* Encodings:: Options controlling source file encoding
* Warnings:: Options controlling warnings specific to gcj
* Code Generation:: Options controlling the output of gcj
* Configure-time Options:: Options you won't use
@end menu
@node Input Options
@section Input Options
@cindex class path
@code{gcj} has options to control where it looks to find input files.
Like other compilers for the Java language, @code{gcj} has a notion of a
@dfn{class path}. There are several options and environment variables
which can be used to manipulate the class path. When @code{gcj} looks
for a given class, it searches the class path looking for the
corresponding @file{.class} file. @code{gcj} comes with a built-in
class path which points at the installed @file{libgcj.jar}, a file which
contains all the standard classes.
In the below, a directory or path component can refer either to an
actual directory on the filesystem, or to a @file{.zip} or @file{.jar}
file, which @code{gcj} will search as if it is a directory.
@table @code
@item -I@var{dir}
All directories specified by @code{-I} are kept in order and prepended
to the class path constructed from all the other options. Unless
compatibility with tools like @code{javac} is imported, we recommend
always using @code{-I} instead of the other options for manipulating the
class path.
@item --classpath=@var{path}
This sets the class path to @var{path}, a colon-separated list of paths
(on Windows-based systems, a semicolon-separate list of paths).
@item --CLASSPATH=@var{path}
This sets the class path to @var{path}, a colon-separated list of paths
(on Windows-based systems, a semicolon-separate list of paths). This
differs from the @code{--classpath} option in that it also suppresses
the built-in system path.
@item CLASSPATH
This is an environment variable which holds a list of paths.
@end table
The final class path is constructed like so:
@itemize @bullet
@item
First come all directories specified via @code{-I}.
@item
If @code{--classpath} is specified, its value is appended and processing
stops. That is, @code{--classpath} suppresses all the options mentioned
later in this list.
@item
If @code{--CLASSPATH} is specified, its value is appended and the
@code{CLASSPATH} environment variable is suppressed.
@item
If the @code{CLASSPATH} environment variable is specified (and was not
suppressed by @code{--CLASSPATH}), then its value is appended.
@item
Finally, the built-in system directory, @file{libgcj.jar}, is appended.
@end itemize
@node Encodings
@section Encodings
The Java programming language uses Unicode throughout. In an effort to
integrate well with other locales, @code{gcj} allows @file{.java} files
to be written using almost any encoding. @code{gcj} knows how to
convert these encodings into its internal encoding at compile time.
You can use the @code{--encoding=@var{NAME}} option to specify an
encoding (of a particular character set) to use for source files. If
this is not specified, the default encoding comes from your current
locale. If your host system has insufficient locale support, then
@code{gcj} assumes the default encoding to be the @samp{UTF-8} encoding
of Unicode.
To implement @code{--encoding}, @code{gcj} simply uses the host
platform's @code{iconv} conversion routine. This means that in practice
@code{gcj} is limited by the capabilities of the host platform.
The names allowed for the argument @code{--encoding} vary from platform
to platform (since they are not standardized anywhere). However,
@code{gcj} implements the encoding named @samp{UTF-8} internally, so if
you choose to use this for your source files you can be assured that it
will work on every host.
@node Warnings
@section Warnings
@code{gcj} implements several warnings. As with other generic
@code{gcc} warnings, if an option of the form @code{-Wfoo} enables a
warning, then @code{-Wno-foo} will disable it. Here we've chosen to
document the form of the warning which will have an effect -- the
default being the opposite of what is listed.
@table @code
@item -Wunsupported-jdk11
This will cause @code{gcj} to warn that @code{final} local variables are
being treated as non-final.
@c FIXME: why do we want this? Is it just not implemented yet?
@item -Wredundant-modifiers
With this flag, @code{gcj} will warn about redundant modifiers. For
instance, it will warn if an interface method is declared @code{public}.
@item -Wextraneous-semicolon
This causes @code{gcj} to warn about empty statements. Empty statements
have been deprecated.
@item -Wno-out-of-date
This option will cause @code{gcj} not to warn when a source file is
newer than its matching class file. By default @code{gcj} will warn
about this.
@item -Wunused
This is the same as @code{gcc}'s @code{-Wunused}.
@item -Wall
This is the same as @code{-Wredundant-modifiers -Wextraneous-semicolon
-Wunused}.
@end table
@node Code Generation
@section Code Generation
In addition to the many @code{gcc} options controlling code generation,
@code{gcj} has several options specific to itself.
@table @code
@item --main=@var{CLASSNAME}
This option is used when linking. Since the linker expects to find a
method simply named @code{main}, and since Java programs won't have such
a method (due to name mangling), at link time @code{gcj} will generate a
stub @code{main} function which will initialize the runtime and then
invoke the @code{main} method of the appropriate class. This option is
used to specify the name of the class whose @code{main} method should be
invoked when the resulting executable is run.
@item -D@var{name}[=@var{value}]
This option can only be used with @code{--main}. It defines a system
property named @var{name} with value @var{value}. If @var{value} is not
specified then it defaults to the empty string. These system properties
are initialized at the program's startup and can be retrieved at runtime
using the @code{java.lang.System.getProperty} method.
@item -C
This option is used to tell @code{gcj} to generate bytecode
(@file{.class} files) rather than object code.
@item -d @var{directory}
When used with @code{-C}, this causes all generated @file{.class} files
to be put in the appropriate subdirectory of @var{directory}. By
default they will be put in subdirectories of the current working
directory.
@c @item -fassume-compiled
@c Nobody is sure what this does and anyway it doesn't work.
@item -fno-bounds-check
By default, @code{gcj} generates code which checks the bounds of all
array indexing operations. With this option, these checks are omitted.
Note that this can result in unpredictable behavior if the code in
question actually does violate array bounds constraints.
@item -fjni
With @code{gcj} there are two options for writing native methods: CNI
and JNI. By default @code{gcj} assumes you are using CNI. If you are
compiling a class with native methods, and these methods are implemented
using JNI, then you must use @code{-fjni}. This option causes
@code{gcj} to generate stubs which will invoke the underlying JNI
methods.
@end table
@node Configure-time Options
@section Configure-time Options
Some @code{gcj} code generations options affect the resulting ABI, and
so can only be meaningfully given when @code{libgcj}, the runtime
package, is configured. @code{libgcj} puts the appropriate options from
this group into a @samp{spec} file which is read by @code{gcj}. These
options are listed here for completeness; if you are using @code{libgcj}
then you won't want to touch these options.
@table @code
@item -fuse-boehm-gc
This enables the use of the Boehm GC bitmap marking code. In particular
this causes @code{gcj} to put an object marking descriptor into each
vtable.
@item -fhash-synchronization
By default, synchronization data (the data used for @code{synchronize},
@code{wait}, and @code{notify}) is pointed to by a word in each object.
With this option @code{gcj} assumes that this information is stored in a
hash table and not in the object itself.
@item -fuse-divide-subroutine
On some systems, a library routine is called to perform integer
division. This is required to get exception handling correct when
dividing by zero.
@end table
@node Compatibility
@chapter Compatibility
As we believe it is important that the Java platform not be fragmented,
@code{gcj} and @code{libgcj} try to conform to the relevant Java
specifications. However, limited manpower and incomplete and unclear
documentation work against us. So, there are caveats to using
@code{gcj}.
This list of compatibility issues is by no means complete.
@itemize @bullet
@item
@code{gcj} implements the JDK 1.1 language. It supports inner classes,
though these are known to still be buggy. It does not yet support the
Java 2 @code{strictfp} keyword (it recognizes the keyword but ignores
it).
@item
@code{libgcj} is missing many packages, most notably @code{java.awt}.
@item
Sometimes the @code{libgcj} implementation of a method or class differs
from the JDK implementation. This is not always a bug. Still, if it
affects you, it probably makes sense to report it so that we can discuss
the appropriate response.
@end itemize
@node Invoking gcjh
@chapter Invoking gcjh
The @code{gcjh} program is used to generate header files from class
files. It can generate both CNI and JNI header files, as well as stub
implementation files which can be used as a basis for implementing the
required native methods.
@table @code
@item -stubs
This causes @code{gcjh} to generate stub files instead of header files.
By default the stub file will be named after the class, with a suffix of
@samp{.cc}. In JNI mode, the default output file will have the suffix
@samp{.c}.
@item -jni
This tells @code{gcjh} to generate a JNI header or stub. By default,
CNI headers are generated.
@item -add @var{text}
Inserts @var{text} into the class body. This is ignored in JNI mode.
@item -append @var{text}
Inserts @var{text} into the header file after the class declaration.
This is ignored in JNI mode.
@item -friend @var{text}
Inserts @var{text} into the class as a @code{friend} declaration.
This is ignored in JNI mode.
@item -prepend @var{text}
Inserts @var{text} into the header file before the class declaration.
This is ignored in JNI mode.
@item --classpath=@var{path}
@itemx --CLASSPATH=@var{path}
@itemx -I@var{directory}
@itemx -d @var{directory}
@itemx -o @var{file}
These options are all identical to the corresponding @code{gcj} options.
@item -o @var{file}
Sets the output file name. This cannot be used if there is more than
one class on the command line.
@item -td @var{directory}
Sets the name of the directory to use for temporary files.
@item --help
Print help about @code{gcjh} and exit. No further processing is done.
@item --version
Print version information for @code{gcjh} and exit. No further
processing is done.
@end table
All remaining options are considered to be names of classes.
@node Invoking jv-scan
@chapter Invoking jv-scan
The @code{jv-scan} program can be used to print information about a Java
source file (@file{.java} file).
@table @code
@item --complexity
This prints a complexity measure, related to cyclomatic complexity, for
each input file.
@item --encoding=@var{name}
This works like the corresponding @code{gcj} option.
@item --print-main
This prints the name of the class in this file containing a @code{main}
method.
@item --list-class
This lists the names of all classes defined in the input files.
@item --list-filename
If @code{--list-class} is given, this option causes @code{jv-scan} to
also print the name of the file in which each class was found.
@item -o @var{file}
Print output to the named file.
@end table
@node Invoking jcf-dump
@chapter Invoking jcf-dump
This is a class file examiner, similar to @code{javap}. It will print
information about a number of classes, which are specifed by class name
or file name.
@table @code
@item -c
Disassemble method bodies. By default method bodies are not printed.
@item --javap
Generate output in @code{javap} format.
@item --classpath=@var{path}
@itemx --CLASSPATH=@var{path}
@itemx -I@var{directory}
@itemx -o @var{file}
These options as the same as the corresponding @code{gcj} options.
@end table
@node Invoking gij
@chapter Invoking gij
@code{gij} is a Java bytecode interpreter included with @code{libgcj}.
@code{gij} is not available on every platform; porting it requires a
small amount of assembly programming which has not been done for all the
targets supported by @code{gcj}.
The primary argument to @code{gij} is the name of a class or, with
@code{-jar}, a jar file. Options before this argument are interpreted
by @code{gij}; remaining options are passed to the interpreted program.
If a class name is specified and this class does not have a @code{main}
method with the appropriate signature (a @code{static void} method with
a @code{String[]} as its sole argument), then @code{gij} will print an
error and exit.
If a jar file is specified then @code{gij} will use information in it to
determine which class' @code{main} method will be invoked.
@code{gij} will invoke the @code{main} method with all the remaining
command-line options.
Note that @code{gij} is not limited to interpreting code. Because
@code{libgcj} includes a class loader which can dynamically load shared
objects, it is possible to give @code{gij} the name of a class which has
been compiled and put into a shared library on the class path.
@table @code
@item -D@var{name}[=@var{value}]
This defines a system property named @var{name} with value @var{value}.
If @var{value} is not specified then it defaults to the empty string.
These system properties are initialized at the program's startup and can
be retrieved at runtime using the @code{java.lang.System.getProperty}
method.
@item -ms=@var{number}
This sets the initial heap size
@item -mx=@var{number}
This sets the maximum heap size.
@item -jar
This indicates that the name passed to @code{gij} should be interpreted
as the name of a jar file, not a class.
@end table
@node Resources
@chapter Resources
The current @code{gcj} home page is
@uref{http://sources.redhat.com/java/}. This is likely to change in the
near future.
For more information on gcc, see @uref{http://gcc.gnu.org/}.
Some @code{libgcj} testing is done using the Mauve test suite. This is
a free software Java class library test suite which is being written
because the JCK is not free. See
@uref{http://sources.redhat.com/mauve/} for more information.
@contents
@bye
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