Compilers

The single most significant change for developers migrating from SunOS release 4.x to the Solaris 2.5 operating environment is the unbundling of the C compiler. One of the factors that allowed the compiler to be unbundled is the dynamic kernel. The compiler is no longer required to reconfigure the kernel as devices are now automatically loaded by the kernel as needed.

An ANSI C compiler is available with the unbundled SPARCworks^(TM) product. This compiler produces executables in executable and linking format (ELF), the native object format of Solaris 2.5 executables. lint and the lint libraries are also unbundled.

Source Compatibility Guide describes the differences between the C language as implemented by the SunOS release 4.x C compiler (Sun C) and as described by the ANSI Programming Language C document (ANSI C). These differences should be addressed when porting source written for the Sun C compiler to an ANSI C conforming compiler.

Compiler Option Differences

Table 15-1 compares the SunOS release 4.x Sun C and ANSI C compilers to the Solaris 2.5 SPARCompiler C++ 3.0.1. It is provided for your information, and is not intended to describe the range of operations available in default Solaris 2.5 software.

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Note - Table 15-1 presents information based on the publicly available copies of the American National Standard for Information Systems - Programming Language XX3.159-1989, approved December 14, 1989.

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Please note the following:

• A "yes" in any column indicates that the option is supported by that compiler.
• If the option has changed, the new option is listed.
• A "no" in any column if the option is not supported by that driver
• A "+" in the SPARCompiler C++ 3.0.1 Solaris 2.5 column indicates an option required by SVID specifications.

Table 15-1

Option or Flag	Sun C (SunOS release 4.x)	ANSI C (SunOS release 4.x)	SPARCompiler C++ 3.0.1 (Solaris 2.5)	Description
-A symbol	No	Yes	Yes	cpp predicate assertion
-a	Yes	Yes	-xa	Counts # basic block executions
-assertx	Yes	Yes	-z	Specifies link time assertion
-align	Yes	Yes	No	Page aligns (ld)
-BX	Yes	Yes	-d[y|n]	Specifies binding type (only for libraries in SunOS release 5.5)
-bnzero	Yes	Yes	No	Generates nonzero AR
-C	Yes	Yes	+Yes	cpp comments left in
-c	Yes	Yes	+Yes	Produces .o file
-cg87	Yes	Yes	No	Sets fp option to -cg87
-cg89	Yes	Yes	No	Sets fp option to -cg89

Table 15-1 (Continued)

Option or Flag	Sun C (SunOS release 4.x)	ANSI C (SunOS release 4.x)	SPARCompiler C++ 3.0.1 (Solaris 2.5)	Description
-dryrun	Yes	Yes	-#	Shows commands constructed by driver
-Dx	Yes	Yes	+Yes	Defines cpp symbol x
-d	Yes	Yes	No	Forces definition of common (ld)
-dalign	Yes	Yes	Yes	Assumes doubles are doubleword aligned
-dl	Yes	Yes	No	Generates long data segment refs
-d[y|n]	-BX	-BX	Yes	Dynamics linking [yes|no]
-E	Yes	Yes	+Yes	Runs source through cpp
-e	No	No	Yes	Entry point for ld
-F	-O*	-O*	+No	Optimization directives
-f	No	No	No	Floating-point support
-fast	Yes	Yes	Yes	Options for best performance
-fsingle	Yes	No	No	Floats are single precision
-fsingle2	Yes	No	No	Passes float as float not double
-fnonstd	Yes	Yes	Yes	Non-standard float option
-fstore	Yes	No	No	Forces writes on store
-G	No	No	Yes	Creates shared library, not available with the -dn option
-g	Yes	Yes	+Yes	Generates info for dbx
-go	Yes	No	No	Generates info for adb
-H	Yes	Yes	Yes	Prints paths of included files
-h name	No	No	Yes	Uses name as internal identifier; soname passed to linker
-help	Yes	Yes	-flags	Lists options
-Ix	Yes	Yes	+Yes	Adds x to include path
-J	sun3	No	No	Generates long offset for switch|case

Table 15-1 (Continued)

Option or Flag	Sun C (SunOS release 4.x)	ANSI C (SunOS release 4.x)	SPARCompiler C++ 3.0.1 (Solaris 2.5)	Description
-KPIC	-PIC	-PIC	Yes	Position independent code
-Kpic	-pic	-pic	Yes	PIC with short offsets
-Kminabi	No	No	Yes	ABI compliant code
-libmil	Yes	Yes	-xlibmil	Passes libm.il as part of -fast
-lx	Yes	Yes	Yes	Reads object library (for ld)
-Lx	Yes	Yes	Yes	Adds x to ld library path
-M	Yes	Yes	No	Collects dependencies
-M mapfile	Yes	No	Yes	Passes mapfile to the linker
-misalign	Yes	Yes	Yes	Handles misaligned Sun-4 data
-N	Yes	No	No	Does not make shared
-n	Yes	No	No	Makes shared
-native	Yes	Yes	No	Uses appropriate -cg option
-nolibmil	Yes	Yes	-xnolibmil	Doesn't pass libm.il with -fast
-noc2	Yes	Yes	No	Doesn't do peephole optimization
-o file	Yes	Yes	+Yes	Sets name of output file
-O[1,2,3,4]	Yes	Yes	-x0[1,2,3,4]	Generates optimized code
-O	Yes	Yes	+Yes	Generates optimized code
-P	Yes	Yes	+Yes	Runs source through cpp, output to .i
-PIC	Yes	No	-KPIC	Generates pic code with long offset
-p	Yes	Yes	+Yes	Collects data for prof
-pic	Yes	Yes	-Kpic	pic code with short offset
-pipe	Yes	No	No	Uses pipes instead of temp files
-pg	Yes	Yes	-xpg	Collects data for gprof
-purecross	Yes	No	No	Doesn't have slash in VROOT
-Qdir x	Yes	Yes	-Y*	Looks for compiler passes in x

Table 15-1 (Continued)

Option or Flag	Sun C (SunOS release 4.x)	ANSI C (SunOS release 4.x)	SPARCompiler C++ 3.0.1 (Solaris 2.5)	Description
-Qpath x	Yes	Yes	-Y*	Same as -Qdir
-Qn	No	No	Yes	Doesn't add version stamp info
-Qy	No	No	Yes	Adds version stamp info
-qdir x	Yes	Yes	-Y*	Looks for compiler passes in x
-qp	-p	-p	+Yes	Collects data for prof
-ql	No	No	+Yes	Collects data for lprof
-qpath x	Yes	Yes	-Y*	Same as -Qdir
-Qoption cpp x	Yes	Yes	No	Passes option x on to program cpp
-Qoption iropt x	Yes	Yes	No	Passes option x on to program iropt
-Qoption cg x	Yes	Yes	No	Passes option x on to program cg
-Qoption inline x	Yes	Yes	No	Passes option x on to program inline
-Qoption as x	Yes	Yes	No	Passes option x on to program as
-Qoption asS x	Yes	Yes	No	Passes option x on to program asS
-Qoption ld x	Yes	Yes	No	Passes option x on to program ld
-qoption cpp x	Yes	Yes	No	Passes option x on to program cpp
-qoption ccom x	Yes	Yes	No	Passes option x on to program ccom
-qoption lint1 x	Yes	Yes	No	Passes option x on to program lint1
-qoption iropt x	Yes	Yes	No	Passes option x on to program iropt
-qoption cg x	Yes	Yes	No	Passes option x on to program cg
-qoption inline x	Yes	Yes	No	Passes option x on to program inline
-qoption cat x	Yes	Yes	No	Passes option x on to program cat
-qoption c2 x	Yes	Yes	No	Passes option x on to program c2
-qoption as x	Yes	Yes	No	Passes option x on to program as

Table 15-1 (Continued)

Option or Flag	Sun C (SunOS release 4.x)	ANSI C (SunOS release 4.x)	SPARCompiler C++ 3.0.1 (Solaris 2.5)	Description
-qoption asS x	Yes	Yes	No	Passes option x on to program asS
-qoption ld x	Yes	Yes	No	Passes option x on to program ld
-Qproduce .o	Yes	Yes	No	Produces type .o file (Object file)
-Qproduce .s	Yes	Yes	No	Produces type .s file (Assembler source)
-Qproduce .c	Yes	Yes	No	Produces type .c file (C source)
-Qproduce .i	Yes	Yes	No	Produces type .i file (C source after cpp)
-qproduce .o	Yes	Yes	No	Produces type .o file (Object file)
-qproduce .s	Yes	Yes	No	Produces type .s file (Assembler source)
-qproduce .c	Yes	Yes	No	Produces type .c file (C source)
-qproduce .i	Yes	Yes	No	Produces type .i file (C source after cpp)
-r	Yes	Yes	Yes	Makes relocatable; pass to linker
-R	Yes	Yes	No	Merges data into text segment
-R	No	No	Yes	Specifies search directories for the run-time linker
-S	Yes	Yes	+Yes	Produces .s file only
-s	Yes	Yes	Yes	Strips (4.1); pass to linker
-sb	Yes	Yes	-xsb	Collects information for code browser
-strconst	No	Yes	-xstrconst	Places string literals in read-only text segment
-sun2	Yes	No	No	Generates code for a Sun-2 system
-sun3x	Yes	No	No	Generates code for a Sun-3ax system
-sun386	Yes	No	No	Generates code for a Sun386i
-sun3	Yes	No	No	Generates code for a Sun-3 system

Table 15-1 (Continued)

Option or Flag	Sun C (SunOS release 4.x)	ANSI C (SunOS release 4.x)	SPARCompiler C++ 3.0.1 (Solaris 2.5)	Description
-sun4c	Yes	No	No	Generates code for a Sun-4c system
-sun4	Yes	No	No	Generates code for a Sun-4 system
-target x	Yes	No	No	Sets target architecture to x
-temp=dir	Yes	Yes	No	Set directory for temps to dir
-time	Yes	Yes	No	Reports the execution times
-u	Yes	Yes	Yes	Enters symbol arg as undef (ld)
-Ux	Yes	Yes	+Yes	Undefines cpp symbol x
-v	Yes	Yes	-#	Verbose mode
-v	No	No	Yes	Strict semantic checking
-V	Yes	Yes	+Yes	Reports versions of programs
-W	No	No	+Yes	Arguments to other components
-w	Yes	Yes	Yes	Does not print warnings
-X[t,a,c,s]	No	Yes	Yes	Compatibility options
-Y	No	No	+Yes	Changes pathname to components
-yx	Yes	No	No	Traces symbol
-z	-assert	-assert	Yes	Turns on asserts in linker
-#	-v	-v	Yes	Verbose mode
EOF	No	No	Yes	File argument

The C compiler accepts the types of filename arguments shown in Table 15-2.

Table 15-2

Suffix	File Type
.a	Object library
.il	In-line expansion file
.o	Object file
.so	Shared object

Table 15-2 (Continued)

Suffix	File Type
.s	Assembler source
.S	Assembler source for cpp
.c	C source
.i	C source after cpp

"file.X=.Y" will read the file "file.X" but treat it as if it had suffix "Y"

Linkers

There are several changes to the link editor, ld(1), in this release. The most important change is its ability to handle the new ELF native file format.

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Note - The recommended method for building libraries and executables is through the compiler driver rather than by invoking the linker directly. The compiler automatically supplies several files needed by the linker.

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Link Editor Option Differences

Some options have been renamed in the new linker, some have remained the same, and others are no longer needed. Table 15-3 compares the SunOS release 4.x ld command to the Solaris 2.5 ld command.

The sections following Table 15-3 explain how certain linking tasks are affected by the option differences.

Table 15-3 ld

SunOS release 4.x Option	Solaris 2.5 Replacement	Notes
-align datum	-M mapfile	Uses mapfiles and distinct sections
-assert definitions	default
-assert nodefinitions	-znodefs	Issues a fatal error instead of a warning
-assert nosymbolic	-zdefs	Issues a fatal error instead of a warning
-assert pure-text	-ztext	Issues a fatal error instead of a warning

Table 15-3 ld(Continued)

SunOS release 4.x Option	Solaris 2.5 Replacement	Notes
-A name	No replacement	dlopen(3X) and dlclose(3X) can approximate this behavior
-Bdynamic	-Bdynamic	Applies only to the inclusion of shared libraries; use -dy (the default) to build dynamically linked executables. See "Building Executables" on page 148.
-Bnosymbolic	-zdefs
-Bstatic	-dn & -Bstatic	Used with the -dn option to completely eliminate the dynamic linker, the -dn option must be specified; use -Bstatic in dynamic mode to include archive libraries. (Used as a toggle. See "Building Executables" on page 148.)
-Bsymbolic	-Bsymbolic	Also gets -assert nosymbolic with this option
-d -dc -dp	Default	Use -b option in SVR4 to turn off
-D hex	-M mapfile	mapfiles contain different mechanisms to accomplish desired effect
-e entry	-e entry
no -e	-G	Creates a shared object
-lx[.v]	-lx	Only major number versioning of shared libraries is currently supported
-Ldir	-Ldir	dir not recorded in executable; use -R option instead.
-M	-m
-n	Default	SVR4 executable format compresses disk image as -n
-N	No replacement
-o name	-o name
-p	Default	Can override with -M mapfile
-r	-r

Table 15-3 ld(Continued)

SunOS release 4.x Option	Solaris 2.5 Replacement	Notes
-S	No replacement
-s	-s
-t	no replacement
-T hex	-M mapfile	mapfiles contain different mechanisms to accomplish desired effect
-Tdata hex	-M mapfile	mapfiles contain different mechanisms to accomplish desired effect
-u name	-u name
-x	No replacement
-X	No replacement
-ysym	No replacement
-z	default	SVR4 executable format demand pages as -z

Building Shared Libraries

The procedure for building shared libraries has changed in the Solaris 2.5 operating environment. The -G option is now required to build a shared library. In SunOS release 4.x, the linker would infer that a shared library was being built by the absense of the -e option. As shared libraries may have entry points, this option can no longer be used.

Building Executables

The -Bdynamic and -Bstatic options are still available, but their behavior is different. These options now refer to library inclusions; not to the executable binding. Executable binding is set exclusively with the new -dy and -dn options in the Solaris 2.5 software. The

-dy option is the default. It is

required to create a dynamically linked executable. The -dn option is required to create a statically linked executable.

The -Bdynamic and -Bstatic options apply only when using the -dy option. -Bdynamic tells the link editor to include shared libraries, while -Bstatic tells it to include archive libraries. These options act as a toggle governing subsequent -l arguments until the next -Bdynamic or -Bstatic option is encountered.

The following examples show SunOS release 4.x and Solaris 2.5 commands that can be used to create similar executables.

sunos4.1% ld -Bstatic test.o -lx # uses libx.a and creates a static executable sunos5.x% cc -dn test.o -lx # uses libx.a and creates a static executable sunos4.1% ld -Bdynamic test.o -lx # uses libx.so and creates a dynamic # executable sunos5.x% cc test.o -lx # uses libx.so and creates a dynamic # executable sunos4.1% ld -Bdynamic test.o -Bstatic -lx # uses libx.a and creates a dynamic # executable sunos5.x% cc test.o -Bstatic -lx # uses libx.a and creates a dynamic # executable

Specifying Library Search Paths

In SunOS release 4.x, directories specified with the -L option were searched at link time and the information retained for use at execution time. This behavior is now divided between the -L and -R options. The -L option specifies the directories to search at link time; the new -R option tells the linker the search paths to be retained for use at run time. See "Search Path Rules," in the next section for more information.

As with the -Bdynamic and -Bstatic options, the position of the -L option has significance; it applies only to the subsequent -l options.

Search Path Rules

The dynamic linker and the run time linker determine their search paths through a different algorithm from that used by the SunOS release 4.x linker.

Table 15-4 through Table 15-6 compare the search paths for the dynamic linker and the run time linker for SunOS release 4.x and the Solaris 2.5 operating environment. Notice that in the latter, the search path for the link editor and the runtime linker are affected by the LD_LIBRARY_PATH setting.

Table 15-4

	Library Search Path
Link Editor	-L, LD_LIBRARY_PATH, /usr/lib, /usr/local/lib
Runtime Linker	LD_LIBRARY_PATH, -L, /usr/lib, /usr/local/lib

Table 15-5 LD_LIBRARY_PATHdirlist1

	Library Search Path LD_LIBRARY_PATH=dirlist1
Link Editor	-L, dirlist1, /usr/ccs/lib, /usr/lib
Runtime Linker	dirlist1, -R, /usr/lib

Table 15-6 LD_LIBRARY_PATHdirlist1dirlist2

	Library Search Path LD_LIBRARY_PATH=dirlist1; dirlist2
Link Editor	dirlist1,-L, dirlist2, /usr/ccs/lib, /usr/lib
Runtime Linker	dirlist1, dirlist2, -R, /usr/lib

Version Numbering

SunOS release 4.x supported both major and minor version numbers on shared libraries. The Solaris 2.5 operating environment supports only the major version number. For binary compatibility support, major and minor version

numbers are recognized on SunOS release 4.x shared libraries. These libraries are required to retain the same major and minor version number they had in SunOS release 4.x.

Table 15-7 shows versions of SunOS release 4.x and Solaris 2.5 shared libraries.

Table 15-7

SunOS release 4.x	Solaris 2.5
libc.so.1.7	libc.so.1
libdl.so.1.0	libdl.so.1

In SunOS release 4.x system software, when the -l option was specified, the build environment linker searched for a library with both major and minor numbers. For example, if -ldl was specified, the library, libdl.so.1.0 was linked. In Solaris 2.5, even though major numbers are still supported, the default behavior of the link editor is to ignore version numbers. Using the previous example, the build environment link editor now searches for libdl.so and a symbolic link points to a specific version file.

The recording of a dependency in a dynamic executable or shared object is, by default, the filename of the associated shared object as it is referenced by the link-editor. To provide a more consistent means of specifying dependencies, shared objects can record within themselves the filename by which they should be referenced at runtime.This is specified with the -h option when linking the library file.

Symbolic links have been created for most libraries in this release. Build any new shared libraries with major numbers, then create a symbolic link to the version of the library that is used most often. .

Examples

A new utility, dump(1) (See "Backing Up and Restoring Files" on page 101), makes it easier to debug object files or to check the static and dynamic linking. The dump -L option displays the information needed by the runtime linker that is contained in the executable. This information is contained in the dynamic section of an ELF file. The RPATH entry displays search paths specified by the -R option to ld.

The following example:

• Builds a shared library, libx.so.1, using libx.o
• Creates a link from libx.so.1 to libx.so
• Shows dump output, including the SONAME field, which stores the information passed with the -h option.

examples% cc -G -o libx.so.1 -h libx.so.1 libx.o examples% cp libx.so.1 /mylibs examples% ln -s /mylibs/libx.so.1 /mylibs/libx.so examples% dump -Lv libx.so.1 libx.so.1: **** DYNAMIC SECTION INFORMATION **** .dynamic : [INDEX] Tag Value [1] INIT 0x3b8 [2] FINI 0x3f4 [3] SONAME libx.so.1 [4] HASH 0x94 [5] STRTAB 0x33c [6] SYMTAB 0x14c [7] STRSZ 0x62 [8] SYMENT 0x10 [9] PLTGOT 0x10404 [10] PLTSZ 0xc [11] PLTREL 0x7 [12] JMPREL 0x3ac [13] RELA 0x3a0 [14] RELASZ 0x18 [15] RELAENT 0xc

If a library needs other dynamic libraries, they should be specified along with an RPATH, as the next example shows.

The next example compiles prog.c, dynamically linking libx.so (as built in the previous example), and specifies that the binary retain the current directory information for execution. This example shows the output of dump from the

compiled program, prog.c. Here, the information stored in the SONAME field of the previous example is shown as NEEDED by prog. When prog is run, it will use libx.so.1, even if libx.so is linked to a different version.

examples% cc -o prog prog.c -L/mylibs -R/mylibs -lx example% dump -Lv prog prog: **** DYNAMIC SECTION INFORMATION **** .dynamic : [INDEX] Tag Value [1] NEEDED libx.so.1 [2] NEEDED libc.so.1 [3] INIT 0x1b1ac [4] FINI 0x1b248 [5] RPATH /mylibs [6] HASH 0x100e8 [7] STRTAB 0x17f90 [8] SYMTAB 0x12be0 [9] STRSZ 0x31e1 [10] SYMENT 0x10 [11] DEBUG 0x0 [12] PLTGOT 0x2b25c [13] PLTSZ 0x30 [14] PLTREL 0x7 [15] JMPREL 0x1b180 [16] RELA 0x1b174 [17] RELASZ 0x3c [18] RELAENT 0xc

Debuggers

This section describes changes to debugging tools.

dbx and dbxtool

These tools are no longer available with default system software. Enhanced versions of these tools are available as the SPARCworks Debugger, an unbundled product.

adb and kadb

These tools are available in the Solaris 2.5 operating environment. They offer the same capabilities as the tools in SunOS release 4.x. kadb has been enhanced to recognize multiple processors. The processor ID is displayed in the kadb prompt. In the following examples, it is 0.

To make kernel debugging under the Solaris 2.5 operating environment easier:

• Enable savecore (uncomment the savecore lines in the /etc/init.d/sysetup file)
• Boot under kadb (type $c when the system crashes)
• Use adb and crash

kadb Macros

The following kadb macros are particularly useful with the new multithreaded kernel:

thread Displays the current thread. The current thread pointer is in SPARC global register g7.

kadb[0]: <g7$<thread

threadlist Shows the stack traces of all the kernel threads in the system. This can be a long list.

kadb[0]: $<threadlist

mutex
Shows you the address of the owning thread, given a mutex. This example
uses the global unsafe driver mutex.

kadb[0]: unsafe_driver$<mutex

moddebug

kadb[0]: moddebug/W 0x80000000

Allows you to watch module loading. See the end of <sys/modctl.h> for legal values for moddebug for debugging purposes only.

Debugging a Live Kernel

Use the following command to debug a live kernel.

# adb -k /dev/ksyms /dev/mem

/dev/ksyms is a pseudo device that contains the complete name list of the running kernel.

truss Command

truss is a new utility, provided to trace system calls performed, signals received, and machine faults incurred. truss offers several significant improvements over the SunOS release 4.x trace(1) command: including the ability to follow forked processes and the ability to deal with multithreaded processes.

The following example shows a summary of traced calls for the date command. With the -c option, truss does not display the trace line-by-line. Instead, it counts the system calls, signals, and faults, and displays a summary.

example% truss -c date Fri Sep 18 14:31:30 PDT 1992 syscall seconds calls errors _exit .00 1 read .00 7 write .00 1 open .03 12 close .00 12 time .00 1 brk .01 4 lseek .00 1 fstat .00 4 ioctl .00 1 execve .00 1 mmap .01 17 munmap .00 8 ---- --- --- sys totals: .05 70 0 usr time: .03 elapsed: .28

See the truss(1) man page in man Pages(1): User Commands for complete details on all truss options.. In Solaris 2.5 there are a number of other new debugging tools which are based on proc(4) such as pmap(1).