C H A P T E R 1

The C++ Compiler

This chapter provides information about the following:

New Features and Functionality of the Sun Studio 10 C++ 5.8 Compiler

Section 1.2, New Features and Functionality of the Sun Studio 10 C++ 5.7 Compiler.

Section 1.4, C++ Readme File.

Section 1.5, Man Pages.

Section 1.6, C++ Utilities.

Section 1.7, Native-Language Support.

1.1 New Features and Functionality of the Sun Studio 10 C++ 5.8 Compiler

This section provides a brief overview of the new C compiler features and functionality introduced in the Sun Studio 10 C++ 5.8 Compiler release. For specific explanations, follow the cross references provided for each item.

New -xarch Flags For x86 Development

The -xarch option now supports the following new flags for development on the x86 platform: amd64a, pentium_proa, ssea, sse2a. See -xarch=isa.

Support For x86 -xpagesize Options

The -xpagesize, -xpagesize_heap, -xpagesize_stack options are now enabled for x86 platforms as well as SPARC. See -xpagesize=n.

A New -xmodel Option To Specify x86 Memory Models

The new -xmodel option lets you specify the kernel, small, or medium memory models on the 64-bit AMD architecture. If the size of your global and static variables exceeds two gigabytes, specify -xmodel=medium. Otherwise, use the default -xmodel=small setting. See -xmodel=[a] for more information.

Support For SSE/SSE2 Integral Media Intrinsics

This release supports intrinsic functions for SSE2 128-bit XMM register integral media-instructions. Include the sunmedia_intrin.h header file in the source code and specify the -xbuiltin option to take advantage of these functions. Furthermore, these intrinsic functions require SSE2 support so specify options such as

          -xarch=sse2, -xarch=amd64, or -xtarget=opteron.

Essentially, the compiler generates inline code for these instrinsic functions. This is easier than manipulating the instructions through assembly language and it can be optimized by the compiler.

For more information about intrinsics, explanations for the function prototypes contained in the header files, and the data types used by these functions, see the 'Intel C++ Intrinsics Reference' section of the Intel(R) C++ Compiler for Linux Systems manual.

New -xvector Flags for x86 SSE2 Platforms

The -xvector option enables automatic generation of calls to the vector library functions and/or the generation of the SIMD (Single Instruction Multiple Data) instructions. See -xvector[=a] for more information.

Binary Optimizer for SPARC

A new -xbinopt option allows the compiler to prepare the binary file for further optimization by the binopt(1) binary optimizer. See -xbinopt={prepare|off} for more information.

Calling Dependent Static Functions From a Function Template

The C++ standard says that function calls that depend on a template parameter can refer only to visible function declarations having external linkage. Specify -features=[no%]tmplrefstatic if your application code depends on the compiler ignoring this rule and calling a dependent static function from a function template. See -features=a[,a...] for more information and examples.

New SPARC -xtarget and -xchip Values

The new -xtarget flags ultra3iplus, ultra4plus, and ultraT1 along with the new -xchip flags ultra3iplus, ultra4plus, and ultraT1 provide code generation for the UltraSPARC IIIiplus, UltraSPARC T1, and UltraSPARC IVplus processors. See -xtarget=t and -xchip=c for more information.

A New Format For Debugger Information

The C++ compiler can now generate debugger information in the dwarf format. The default is still the stabs format, but you can generate dwarf data by setting the new option -xdebugformat to -xdebugformat=dwarf. See -xdebugformat=[stabs|dwarf].

Enhancements to the STACKSIZE Environment Variable

The syntax of the STACKSIZE environment variable has been enhanced to accept a units keyword for denoting the slave thread stacksize: B for Bytes, K for Kilobytes, M for Megabytes, G for Gigabytes.

For example, setenv STACKSIZE 8192 sets the slave thread stack size to 8 MB. 1235B sets the slave thread stack size for 1235 Bytes. 1235G sets it for 1235 Gigabytes. The default for an integer value without a suffix letter is still Kilobytes.

OpenMP Autoscoping

Autoscoping is now available for C++ programs. This feature is described in chapter 3 of the Sun Studio OpenMP API User's Guide.

1.2 New Features and Functionality of the Sun Studio 10 C++ 5.7 Compiler

This section provides a brief overview of the new C++ compiler features and functionality introduced in the Sun Studio 10 C++ 5.7 Compiler release. For specific explanations, follow the cross references provided for each item.

A new -xarch option, -xarch=amd64, specifies compilation for the 64-bit AMD instruction set. For more information about -xarch=amd64, see Section A.2.105, -xarch=isa.

A new -xtarget option, -xtarget=opteron, specifies the -xarch, -xchip, and -xcache settings for 32-bit AMD compilation. For more information about -xtarget=opteron, see Section A.2.167, -xtarget=t.

Note - You must specify -xarch=amd64 to the right of -fast and -xtarget on the command line to generate 64-bit code. For example, specify CC -fast -xarch=amd64 or CC -xtarget=opteron -xarch=amd64. The new -xtarget=opteron option does not automatically generate 64-bit code. It expands to -xarch=sse2, -xchip=opteron, and -xcache=64/64/2:1024/64/16 which results in 32-bit code. The -fast option also results in 32-bit code because it is a macro which also defines -xtarget=native.

The existing -xarch=generic64 option now supports the x86 platform in addition to the traditional SPARC platform.

The C++ compiler now predefines __amd64 and __x86_64 when you specify -xarch=amd64.

A new x86-only flag for the -xregs option, -xregs=[no%]frameptr, lets you use the frame-pointer register as an unallocated callee-saves register to increase the run-time performance of applications.

For more information about -xregs=[no%]frameptr, see Section A.2.160, -xregs=r[,r...].

The C++ compiler now supports template-template parameters. This means that you can specify a template definition with parameters that are themselves templates, rather than types or values. Recall that a template instantiated on a type is itself a type. Consider the following code example:

template<typename T> class MyClass { ... };

std::list< MyClass<int> > x;

Since MyClass<int> is a type, the code example does not use template-template parameters. However, in the following code example, the class template C has a parameter that is a class template, and object x is an instance of C using class template A as its argument. Member y of C has type A<int>.

// ordinary class template

template<typename T> class A {

    T x;

};

// class template having a template parameter

template< template<typename U> class V > class C {

    V<int> y;

};

// instantiate C on template

C<A> x;

The C++ compiler, in default standard mode, now allows nested classes to access private members of the enclosing class.

The C++ standard says that nested classes have no special access to members of the enclosing class. However, most people feel this restriction is not justified because member functions have access to private members, so member classes should too. In the following example, function foo tries to access a private member of class outer. According to the C++ standard, the function has no access unless it is declared a friend function:

class outer {

    int i; // private in outer

    class inner {

        int foo(outer* p) {

            return p->i; // invalid

};

};

The C++ Committee is in the process of adopting a change to the access rules giving the same access to member classes that member functions have. Many compilers have implemented this rule in anticipation of the changed language rule.

To restore the old compiler behavior, disallowing the access, use the compiler option -features=no%nestedaccess. The default is -features=nestedaccess. For more information on -features, see Section A.2.19, -features=a[,a...].

This release provides OpenMP API for shared-memory parallelism on both the Solaris OS on x86 based systems as well as the Solaris OS on SPARC based systems. The same functionality is now enabled on both platforms.

1.3 Standards Conformance

The C++ compiler (CC) supports the ISO International Standard for C++, ISO IS 14882:1998, Programming Language--C++. The readme file that accompanies the current release describes any departures from requirements in the standard.

On SPARC platforms, the compiler provides support for the optimization-exploiting features of SPARC V8 and SPARC V9, including the UltraSPARC implementation. These features are defined in the SPARC Architecture Manuals, Version 8 (ISBN 0-13-825001-4), and Version 9 (ISBN 0-13-099227-5), published by Prentice-Hall for SPARC International.

In this document, "Standard" means conforming to the versions of the standards listed above. "Nonstandard" or "Extension" refers to features that go beyond these versions of these standards.

The responsible standards bodies may revise these standards from time to time. The versions of the applicable standards to which the C++ compiler conforms may be revised or replaced, resulting in features in future releases of the Sun C++ compiler that create incompatibilities with earlier releases.

1.4 C++ Readme File

The C++ compiler's readme file highlights important information about the compiler, including:

Information discovered after the manuals were printed

New and changed features

Software corrections

Problems and workarounds

Limitations and incompatibilities

Shippable libraries

Standards not implemented

To view the text version of the C++ readme file, type the following at a command prompt:

example% CC -xhelp=readme

To access the HTML version of the readme, in your Netscape Communicator 4.0 or compatible version browser, open the following file:

/opt/SUNWspro/docs/index.html

(If your C++ compiler-software is not installed in the /opt directory, ask your system administrator for the equivalent path on your system.) Your browser displays an index of HTML documents. To open the readme, find its entry in the index, then click the title.

1.5 Man Pages

Online manual (man) pages provide immediate documentation about a command, function, subroutine, or collection of such things.

You can display a man page by running the command:

example% man topic

Throughout the C++ documentation, man page references appear with the topic name and man section number: CC(1) is accessed with man CC. Other sections, denoted by ieee_flags(3M) for example, are accessed using the -s option on the man command:

example% man -s 3M ieee_flags

1.6 C++ Utilities

The following C++ utilities are now incorporated into traditional UNIX^® tools and are bundled with the UNIX operating system:

lex--Generates programs used in simple lexical analysis of text

yacc--Generates a C function to parse the input stream according to syntax

prof--Produces an execution profile of modules in a program

gprof--Profiles program runtime performance by procedure

tcov--Profiles program runtime performance by statement

See Program Performance Analysis Tools and associated man pages for further information on these UNIX tools.

1.7 Native-Language Support

This release of C++ supports the development of applications in languages other than English, including most European languages and Japanese. As a result, you can easily switch your application from one native language to another. This feature is known as internationalization.

In general, the C++ compiler implements internationalization as follows:

C++ recognizes ASCII characters from international keyboards (in other words, it has keyboard independence and is 8-bit clean).

C++ allows the printing of some messages in the native language.

C++ allows native-language characters in comments, strings, and data.

C++ supports only Extended UNIX Character (EUC) compliant character sets - a character set in which every null byte in a string is the null character and every byte in the string with the ascii value of '/' is the '/' character.

Variable names cannot be internationalized and must be in the English character set.

You can change your application from one native language to another by setting the locale. For information on this and other native-language support features, see the operating system documentation.