David R. Hanson
Department of Computer Science, Princeton University,
35 Olden St.,
Princeton, NJ 08544
Extract the distribution into its own directory. All paths below are relative to this directory. The distribution holds the following subdirectories.
Installation involves three steps performed in the following order.
doc/install.html is the HTML file for this document. doc/install.ps and doc/install.txt are PostScript and plain ASCII versions.
Include files are in directories named include/target-system; the meaningful combinations are
For example, if the paths shown above are chosen and if include/mips-ultrix has the appropriate include files, install the man page and include files by
% cp etc/lcc.1 /usr/local/man/man1 % cp include/mips-ultrix/*.h /usr/local/include/ansi
Debug your version of the driver by running it with the -v -v options, which cause it to echo the commands it would execute, but not to execute them.
Here's etc/hart.c, which we'll use as an example in describing how to edit a host-specific part. This example illustrates all of the important features.
/* DECStations running ULTRIX at Princeton University */
#include <string.h>
char *cpp[] = {
"/usr/gnu/lib/gcc-cpp", "-undef",
"-DLANGUAGE_C", "-D_LANGUAGE_C", "-D__LANGUAGE_C",
"-D_unix", "-D__unix", "-Dultrix", "-D_ultrix", "-D__ultrix",
"-Dmips", "-D_mips", "-D__mips",
"-Dhost_mips", "-D_host_mips", "-D__host_mips",
"-DMIPSEL", "-D_MIPSEL", "-D__MIPSEL",
"$1", "$2", "$3", 0 };
char *include[] = { "-I/usr/local/include/ansi", 0 };
char *com[] = { "/usr/local/lib/rcc", "-target=mips-ultrix",
"$1", "$2", "$3", 0 };
char *as[] = { "/bin/as", "-o", "$3", "", "$1",
"-nocpp", "-EL", "$2", 0 };
char *ld[] = { "/usr/bin/ld", "-o", "$3", "/usr/lib/crt0.o",
"$1", "$2", "", "", "-lm", "-lc", 0 };
int option(arg) char *arg; {
if (strcmp(arg, "-g") == 0)
as[3] = "-g";
else if (strcmp(arg, "-p") == 0
&& strcmp(ld[3], "/usr/lib/crt0.o") == 0) {
ld[3] = "/usr/lib/mcrt0.o";
ld[7] = "/usr/lib/libprof1.a";
} else if (strcmp(arg, "-b") == 0
&& access("/usr/local/lib/bbexit.o", 4) == 0)
ld[6] = "/usr/local/lib/bbexit.o";
else
return 0;
return 1;
}
Most of the host-specific code is data that
gives prototypes for the commands that invoke
the preprocessor, compiler, assembler, and loader.
Each command prototype is an array of pointers to strings
terminated with a null pointer;
the first string is the full path name of the command and the others
are the arguments or argument placeholders, which are described below.The cpp array gives the command for running the preprocessor. lcc is intended to be used with an ANSI preprocessor, such as the GNU C preprocessor available from the Free Software Foundation. If the GNU preprocessor is used, it must be named gcc-cpp in order for lcc's -N option to work correctly.
Literal arguments specified in prototypes, e.g., "-Dmips" in the cpp command above, are passed to the command as given.
The strings "$1", "$2", and "$3" in prototypes are placeholders for lists of arguments that are substituted in a copy of the prototype before the command is executed. $1 is replaced by the options specified by the user; for the preprocessor, this list always contains at least -Dunix and -D__LCC__. $2 is replaced by the input files, and $3 is replaced by the output file.
Zero-length arguments after replacement are removed from the argument list before the command is invoked. So, e.g., if the preprocessor is invoked without an output file, "$3" becomes "", which is removed from the final argument list.
For example, to specify a preprocessor command prototype to invoke /bin/cpp with the options -Dmips and -Dultrix, the cpp array would be
char *cpp[] = { "/bin/cpp", "-Dmips", "-Dultrix",
"$1", "$2", "$3", 0 };
The include array is a list of -I options that
specify which directives should be searched to satisfy include directives.
These directories are searched in the order given.
The first directory should be the one to which the ANSI
header files were copied in Sec. 2.
The driver adds these options to cpp's arguments
when it invokes the preprocessor, except when -N is specified.Design this list carefully. Mixing ANSI and pre-ANSI headers (e.g., by listing /usr/include after the directory of ANSI headers shown above) may mix incompatible headers. Unless the default list holds only /usr/include or only the ANSI headers, many users may be forced to use -N and -I incessantly.
com gives the command for invoking the compiler. This prototype can appear as shown above, with two important changes. The command name should be edited to reflect the location of the compiler chosen in Sec. 2, and the option -target=mips-ultrix should be edited to the target-system for your host. lcc can generate code for all of the target-system combinations listed in Sec. 2. The -target option specifies the default combination. The driver's -Wf option can be used to specify other combinations; the man page elaborates.
as gives the command for invoking the assembler.
ld gives the command for invoking the loader. For the other commands, the list $2 contains a single file; for ld, $2 contains all `.o' files and libraries, and $3 is a.out, unless the -o option is specified. As suggested in the code above, ld must also specify the appropriate startup code and default libraries.
The option function is described below; for now, use an existing option function or one that returns 0.
After specifying the prototypes, compile the driver by
% cd etc % make HOST=hartwhere hart is replaced by yourhostname. Run the resulting a.out with the options -v -v to display the commands that would be executed, e.g.,
% a.out -v -v foo.c baz.c mylib.a -lX11 a.out $Revision: 3.1 $ $Date: 1994/09/07 11:37:52 $ foo.c: /usr/gnu/lib/gcc-cpp -undef -DLANGUAGE_C -D_LANGUAGE_C -D__LANGUAGE_C -D_unix -D__unix -Dultrix -D_ultrix -D__ultrix -Dmips -D_mips -D__mips -Dhost_mips -D_host_mips -D__host_mips -DMIPSEL -D_MIPSEL -D__MIPSEL -Dunix -D__LCC__ -v -I/usr/local/include/ansi foo.c | /usr/local/lib/rcc -target=mips-ultrix -v - /tmp/lcc12511.s /bin/as -o foo.o -nocpp -EL /tmp/lcc12511.s baz.c: /usr/gnu/lib/gcc-cpp -undef -DLANGUAGE_C -D_LANGUAGE_C -D__LANGUAGE_C -D_unix -D__unix -Dultrix -D_ultrix -D__ultrix -Dmips -D_mips -D__mips -Dhost_mips -D_host_mips -D__host_mips -DMIPSEL -D_MIPSEL -D__MIPSEL -Dunix -D__LCC__ -v -I/usr/local/include/ansi baz.c | /usr/local/lib/rcc -target=mips-ultrix -v - /tmp/lcc12511.s /bin/as -o baz.o -nocpp -EL /tmp/lcc12511.s /usr/bin/ld -o a.out /usr/lib/crt0.o foo.o baz.o mylib.a -lX11 -lm -lc rm /tmp/lcc12511.sLeading spaces indicate lines that have been folded manually to fit this page. Note the use of a pipeline to connect the preprocessor and compiler. lcc arranges this pipeline itself; it does not call the shell. If you want lcc to use temporary files instead of a pipeline, define PIPE=0 in CFLAGS when making the driver:
% make CFLAGS='-DPIPE=0' HOST=hartThe option -pipe forces lcc to use a pipeline between the preprocessor and the compiler regardless of PIPE's value.
As the output shows, lcc places temporary files in /tmp. Alternatives can be specified by defining TEMPDIR in CFLAGS when making the driver, e.g.,
% make CFLAGS='-DTEMPDIR=\"/usr/tmp\"' HOST=hartcauses lcc to place temporary files in /usr/tmp. Once the driver is completed, install it by
% cp a.out /usr/local/bin/lccwhere the destination is the location chosen for lcc in Sec. 2.
The option function is called for the options -g, -p, -pg, and -b because these compiler options might also affect the loader's arguments. For these options, the driver calls option(arg) to give the host-specific code an opportunity to edit the ld command, if necessary. option can change ld, if necessary, and return 1 to announce its acceptance of the option. If the option is unsupported, option should return 0.
For example, in response to -g, the option function shown above changes as[3] from "" to "-g", which specifies the debugging option to the assembler. If -g is not specified, the "" argument is omitted from the as command because it's empty.
Likewise, the -p causes option to change the name of the startup code and add the name of the profiling library. Note that option has been written to support simultaneous use of -g and -p, e.g.,
% a.out -v -v -g -p foo.s baz.o -o myfoo a.out $Revision: 3.1 $ $Date: 1994/09/07 11:37:52 $ /bin/as -o foo.o -g -nocpp -EL foo.s /usr/bin/ld -o myfoo /usr/lib/mcrt0.o foo.o baz.o /usr/lib/libprof1.a -lm -lc rm /tmp/lcc12516.sOn Suns, the driver also recognizes -Bstatic and -Bdynamic as linker options, and recognizes but ignores Sun's `-target name' option.
The option -Woarg causes the driver to pass arg to option. Such options have no other effect; this mechanism is provided to support system-specific options that affect the commands executed by the driver.
The -b option causes the compiler to generate code to count the number of times each expression is executed. The exit function in etc/bbexit.c writes these counts to prof.out when the program terminates. If option is called with -b, it must edit the ld command accordingly, as shown above. This version of option uses the access system call to insure that bbexit.o is installed before editing the ld command. To install bbexit.o execute
% make bbexit.o % cp bbexit.o /usr/local/lib/bbexit.oIf necessary, change /usr/local/lib to reflect local conventions. The exit function in etc/bbexit.c works on the systems listed in Sec. 2, but may need to be modified for other systems.
If option supports -b, you should also install etc/bprint.c, which reads prof.out and generates a listing annotated with execution counts. After lcc is installed, install bprint with the commands
% make bprint % cp bprint /usr/local/bin/bprint % cp bprint.1 /usr/local/man/man1The makefile uses lcc to compile bprint.c; you must use lcc or another ANSI C compiler, e.g., gcc, because bprint.c is written in ANSI C. Also, bprint.c includes "../src/profio.c", so it must be compiled in etc.
To complete the driver, write an appropriate option function for your system, and make and install the driver as described above.
The object files, rcc, and the generated code for the programs in the test suite are placed in the directory target-system where target and system are the names of your target machine and its operating system, respectively. There are directories for the supported target-system combinations, e.g., mips-ultrix.
The default target in src/makefile is rcc. lcc is built by executing make from the apppropriate target-system directory and specifying system-specific values for CFLAGS and LDFLAGS, if necessary. For example, to build rcc for a MIPS running Ultrix, execute the commands
% cd mips-ultrix % make -f ../src/makefile cc -c -O ../src/alloc.c ... cc -c -O ../src/x86.c cc -o rcc alloc.o bind.o dag.o ... mips.o sparc.o x86.oThere may be a few warnings, but there should be no errors. If your host is an SGI machine running IRIX 4.0 or later, you might need CFLAGS=-cckr. If cc doesn't automatically search the directory that holds the source file, specify CFLAGS=-I../src. If you use gcc, specify CFLAGS="-ansi -fno-builtin".
Once rcc is built with the host C compiler, run the test suite to verify that rcc is working correctly. The commands in src/makefile run the shell script src/run on each C program in the test suite, tst/*.c. It uses the driver, lcc, so you must have the driver installed before testing rcc. The target-system combination is read from the variable TARGET, which is specified when invoking make:
% make -f ../src/makefile TARGET=mips-ultrix test ../rcc mips-ultrix 8q: ../rcc mips-ultrix array: ../rcc mips-ultrix cf: ../rcc mips-ultrix cq: ../rcc mips-ultrix cvt: ../rcc mips-ultrix fields: ../rcc mips-ultrix front: ../rcc mips-ultrix incr: ../rcc mips-ultrix init: ../rcc mips-ultrix limits: ../rcc mips-ultrix paranoia: ../rcc mips-ultrix sort: ../rcc mips-ultrix spill: ../rcc mips-ultrix stdarg: ../rcc mips-ultrix struct: ../rcc mips-ultrix switch: ../rcc mips-ultrix wf1: ../rcc mips-ultrix yacc:For each C program in the test suite, src/run compiles the program and uses diff to compare the generated assembly code with the expected code (the MIPS code expected for tst/8q.c is in mips-ultrix/tst/8q.s.bak, etc.). If there are differences, the script executes the generated code with the input given in tst (the input for tst/8q.c is in tst/8q.0, etc.) and compares the output with the expected output (the expected output from tst/8q.c on the MIPS is in mips-ultrix/tst/8q.1.bak, etc.). The script also compares the diagnostics from the compiler with the expected diagnostics.
On some systems, there may be a few differences between the generated code and the expected code. These differences occur because the expected code is generated by cross compilation on a MIPS and the least-significant bits of some floating-point constants differ from those bits in constants generated on your system. There should be no differences in the output from executing the test programs.
The ../rcc and mips-ultrix preceding the name of each test program in the output above indicate the compiler and the target, e.g., `../rcc is generating code for a mips running the ultrix operating system.'
Next, build rcc again using the just-built rcc:
% make -f ../src/makefile TARGET=mips-ultrix triple rm -f *.o make -f ../src/makefile CC='lcc -B./ -d0.1 -A' CFLAGS='-Wf-target=mips-ultrix -I../src/../include/mips-ultrix -I../src' LDFLAGS='' lcc -B./ -d0.1 -A -c -Wf-target=mips-ultrix -I../src/../include/mips-ultrix -I../src ../src/alloc.c ... lcc -B./ -d0.1 -A -o rcc alloc.o bind.o dag.o decl.o ... x86.o strip rcc od +8This command builds rcc twice; once using the rcc built by cc and again using the rcc built by lcc. After building each version, an octal dump of the resulting binary is made, and the two dumps are compared. They should be identical, as shown at the end of the output above. If they aren't, our compiler is generating bad code; contact us.od2 rm -f *.o make -f ../src/makefile CC='lcc -B./ -d0.1 -A' CFLAGS='-Wf-target=mips-ultrix -I../src/../include/mips-ultrix -I../src' LDFLAGS='' lcc -B./ -d0.1 -A -c -Wf-target=mips-ultrix -I../src/../include/mips-ultrix -I../src ../src/alloc.c ... lcc -B./ -d0.1 -A -o rcc alloc.o bind.o dag.o decl.o ... x86.o strip rcc od +8 od3 cmp od[23] && rm od[23]
The final version of rcc should also pass the test suite; i.e., the output from
make -f ../src/makefile TARGET=mips-ultrix testshould be identical to that from the previous make test.
Now install the final version of rcc:
% cp rcc /usr/local/lib/rccwhere the destination is the location chosen for rcc in Sec. 2.
On some systems, you may be able to use environment variables and make's -e option to avoid specifying TARGET on each make command, and the make commands described above can be done with a single command:
% setenv TARGET mips-ultrix % cd mips-ultrix % make -e -f ../src/makefile test triple test cleanmake clean cleans up, but does not remove rcc, and make clobber cleans up and removes rcc.
The code generators for the other targets can be tested by running make from the appropriate target-specific directory and setting some environment variables to control what src/run does. For example, if you built mips-ultrix/rcc and installed it in /usr/local/lib/rcc, you can test the SPARC code generator for the SunOS operating system as follows.
% setenv REMOTEHOST noexecute % setenv BUILDDIR /usr/local/lib/ % cd sparc-sun % make -f ../src/makefile RCC= TARGET=sparc-sun test /usr/local/lib/rcc sparc-sun 8q: /usr/local/lib/rcc sparc-sun array: /usr/local/lib/rcc sparc-sun cf: /usr/local/lib/rcc sparc-sun cq: /usr/local/lib/rcc sparc-sun cvt: /usr/local/lib/rcc sparc-sun fields: /usr/local/lib/rcc sparc-sun front: /usr/local/lib/rcc sparc-sun incr: /usr/local/lib/rcc sparc-sun init: /usr/local/lib/rcc sparc-sun limits: /usr/local/lib/rcc sparc-sun paranoia: /usr/local/lib/rcc sparc-sun sort: /usr/local/lib/rcc sparc-sun spill: /usr/local/lib/rcc sparc-sun stdarg: /usr/local/lib/rcc sparc-sun struct: /usr/local/lib/rcc sparc-sun switch: /usr/local/lib/rcc sparc-sun wf1: /usr/local/lib/rcc sparc-sun yacc:As above, src/run compares the SPARC code generated with what's expected. There should be no differences. Setting REMOTEHOST to noexecute suppresses the assembly and execution of the generated code. BUILDDIR gives the directory that holds rcc, and specifying RCC= to make insures that rcc is not rebuilt in the sparc-sun directory.
If you set REMOTEHOST to the name of a SPARC machine to which you can rlogin, src/run will rcp the generated code to that machine and execute it there, if necessary. See src/run for the details.
Once everything is installed, you can use lcc as a cross compiler. The options -S and -Wf-target=target-system generate assembly code for the specified target, which is any of those listed in Sec. 2. For example,
% lcc -Wf-target=sparc-sun -S tst/8q.cgenerates SPARC code for tst/8q.c in 8q.s.
lcc can also generate code for a `symbolic' target. This target is used routinely in front-end development, and its output is a printable representation of the input program, e.g., the dags constructed by the front end are printed, and other interface functions print their arguments. You can specify this target with the option -Wf-target=symbolic. For example,
% lcc -Wf-target=symbolic -S tst/8q.cgenerates symbolic output for tst/8q.c in 8q.s. Finally, the option -Wf-target=null specifies the `null' target for which lcc emits nothing and thus only checks the syntax and semantics of its inputs files.
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