4.3. Pre-Defined Macro Symbols¶

Many applications support a variety of configurations that are often administered via the use of pre-defined macro symbols.

While several pre-defined macro symbols supported by the cl2000 compiler are also supported by the c29clang compiler, many are not. For a given cl2000 pre-defined macro symbol that is not supported by the c29clang compiler, there are ways one can successfully transition the use of such a pre-defined symbol to be compatible with the c29clang compiler.

This section of the “Migrating C and C++ Source Code” chapter of the migration guide lists each of the pre-defined macro symbols that are supported in the cl2000 compiler and, if conversion is needed, explains how to modify the C/C++ source to make it compatible with the c29clang compiler.

For details about macro symbols that are pre-defined by the c29clang compiler, see Generic Compiler Pre-Defined Macro Symbols.

4.3.1. Pre-Defined Macro Symbols that are Available in Both cl2000 and c29clang¶

Some pre-defined macro symbols supported by the cl2000 compiler are also supported by the c29clang compiler. The following table identifies those pre-defined macro symbols that are supported by both compilers and require no conversion when migrating an application from cl2000 to c29clang:

Macro Symbol

Description / Comments

__COUNTER__

References to the __COUNTER__ macro symbol expand to an

integer value starting from 0. This symbol can be used

in conjunction with a “##” operator in C/C++ source code

to create unique symbol names.

__cplusplus

The __cplusplus symbol is defined if the cl2000 or

c29clang compiler is invoked to process a C++ source

file. If the source file in question is an obvious C++

source file with a .cpp extension, then both compilers

define __cplusplus when processing such a file. The

user can also force __cplusplus to be defined via the

cl2000 -fg option or the c29clang -x c++ option. These

instruct the compiler to process a source file, whether

it is a C++ or C file, as a C++ file.

__DATE__

References to the __DATE__ macro symbol expand to a

string representing the date on which the compiler was

invoked. The date is displayed in the form: mmm dd yyyy.

__ELF__

The __ELF__ macro symbol is defined by both the cl2000 and

c29clang compilers, since both generate ELF object format.

__FILE__

References to the __FILE__ macro symbol expand to a string

representation of the name of the source file being compiled.

_INLINE

Defined if some level of optimization is specified when the compiler is invoked.

The cl2000 compiler allows C/C++ source code to undefine the

_INLINE symbol to disable some optimization while processing C/C++ source.

The c29clang compiler does not support turning off inlining by

undefining macros. The c29clang compiler additionally supports the

the __GNUC_GNU_INLINE__, __GNUC_STDC_INLINE__, and __NO_INLINE__ macros, so that

code can test to see what type of inlining is enabled.

__LINE__

References to the __LINE__ macro symbol expand to an

integer constant indicating the current source line in

the source file. The value of the integer constant

depends on which source line the macro symbol is referenced.

__STDC__

Both the cl2000 and c29clang compilers define the

__STDC__ macro symbol to indicate compliance with the

ISO C standard. Please refer to the TI C28x Optimizing C/C++

Compiler User’s Guide for exceptions to ISO C compliance

that apply to the cl2000 compiler. Exceptions to ISO C

compliance in the c29clang compiler can be found in

the TI C29x Clang Compiler User Guide.

__STDC_HOSTED__

The __STDC_HOSTED__ macro symbol is always defined to 1 to indicate that the

target is a hosted environment, meaning the standard C library is available.

__STDC_NO_THREADS__

The __STDC_NO_THREADS__ macro symbol is always defined to 1 to indicate the

implementation does not support optional standard threads.

__STDC_VERSION__

The __STDC_VERSION__ macro symbol expands to an integer

constant that indicates the ISO C standard that the

compiler conforms to.

__TIME__

References to the __TIME__ macro symbol expand to a

string representation of the time at which the compiler

is invoked. The time is displayed in the form: hh:mm:ss.

__TIMESTAMP__

References to the __TIMESTAMP__ macro symbol expand to a

string representation of the date and time at which the

compiler was invoked. The date and time are displayed in

the form: dow mmm dd hh:mm:ss yyyy (dow is “day of the week”).

__VERSION__

The __VERSION__ macro symbol provides information about

which version of the C/C++ parser is used by the compiler.

The cl2000 compiler uses some version of the EDG

gcc-compatible parser, whereas the c29clang compiler’s

parser uses a version of the LLVM and Clang source base.

4.3.2. Converting cl2000 Pre-Defined Macro Symbols to c29clang Compatible Form¶

Several cl2000 pre-defined macro symbols are not supported by c29clang, but these macro symbols can often be re-written in terms of GCC pre-defined macro symbols that c29clang does support. The following table lists cl2000 pre-defined macro symbols that are not supported by the c29clang compiler, and how they may be converted to a form that is supported by c29clang:

cl2000 Macro Symbol	c29clang Equivalent
__little_endian__	defined(_LITTLE_ENDIAN_)

The cl2000 compiler defines the __little_endian__ macro symbol to indicate that the compiler uses little-endian mode. References to __little_endian__ can safely be replaced with a test that evaluates to True, since the C29x architecture does not support big-endian mode.

The c29clang compiler defines the _LITTLE_ENDIAN_ macro symbol in all cases, because only little-endian mode is supported.

cl2000 Macro Symbol	c29clang Equivalent
__PTRDIFF_T_TYPE__	__PTRDIFF_TYPE__

The cl2000 compiler defines the __PTRDIFF_T_TYPE__ macro symbol to indicate the equivalent base type associated with the ptrdiff_t type.

The c29clang compiler defines __PTRDIFF_TYPE__ to reflect the underlying type for the ptrdiff_t typedef.

cl2000 Macro Symbol	c29clang Equivalent
__SIZE_T_TYPE__	__SIZE_TYPE__

The cl2000 compiler defines the __SIZE_T_TYPE__ macro symbol to indicate the equivalent base type associated with the size_t type.

The c29clang compiler defines __SIZE_TYPE__ to reflect the underlying type for the size_t typedef.

cl2000 Macro Symbol	c29clang Equivalent
__TI_COMPILER_VERSION__	__ti_version__

The cl2000 compiler defines the __TI_COMPILER_VERSION__ macro symbol to a 7-9 digit integer, depending on if X has 1, 2, or 3 digits. The number does not contain a decimal. For example, version 3.2.1 is represented as 3002001. The leading zeros are dropped to prevent the number being interpreted as an octal.

The c29clang compiler defines __ti_version__ to encode the major, minor, and patch version number values associated with the current release, where:
<encoding> = <major> * 10000
             <minor> * 100
             <patch>
For 3.2.1.LTS, for example, the value of <encoding> would be 30201.

cl2000 Macro Symbol	c29clang Equivalent
__TI_EABI__	defined(__ELF__)

Both the cl2000 and c29clang compilers support the generation of ELF object format code only. Consequently, the cl2000 __TI_EABI__ macro symbol is always defined when the cl2000 compiler is invoked.

c29clang does not support __TI_EABI__, but it does support the __ELF__ macro symbol which is also supported by cl2000. Therefore, references to __TI_EABI__ in the C/C++ source can be safely replaced by __ELF__.

cl2000 Macro Symbol	c29clang Equivalent
__TI_GNU_ATTRIBUTE_SUPPORT__	defined(__clang__)

The cl2000 compiler defines the __TI_GNU_ATTRIBUTE_SUPPORT__ macro symbol to indicate that a C/C++ dialect mode where generic attributes is supported. c29clang does not support an analogous macro symbol, but generic attributes are supported by c29clang, nonetheless.

cl2000 Macro Symbol	c29clang Equivalent
__TI_STRICT_ANSI_MODE__	__STRICT_ANSI__

The cl2000 compiler defines the __TI_STRICT_ANSI_MODE__ macro symbol to 1 if the cl2000 compiler is invoked with the --strict_ansi option. The cl2000 compiler defines __TI_STRICT_ANSI_MODE__ with a value of 0 by default to indicate that the compiler does not enforce strict conformance to the ANSI C standard.

The c29clang compiler defines the __STRICT_ANSI__ macro symbol if any of the --std=<spec> options are specified on the c29clang command-line (where spec indicates the identity of a C or C++ language standard).

cl2000 Macro Symbol	c29clang Equivalent
__TMS320C2000__	__C29__

The cl2000 compiler defines the __TMS320C2000__ macro symbol to true to indicated the application is compiled for the TI C28x architecture.

The c29clang compiler defines __C29__ to 1 if the application is compiled for a C29 target. See TI C29x-Specific Pre-Defined Macro Symbols for related macro symbols.

cl2000 Macro Symbol	c29clang Equivalent
__WCHAR_T_TYPE__	__WCHAR_TYPE__

The cl2000 compiler defines the __WCHAR_T_TYPE__ macro symbol to indicate the equivalent base type associated with the wchar_t type.

The c29clang compiler supports the analogous GCC __WCHAR_TYPE__ macro symbol to indicate the underlying type for the wchar_t typedef.

4.3.3. Pre-Defined Macro Symbols in cl2000 that are Not Applicable in c29clang¶

There are several pre-defined macro symbols that are supported by the cl2000 compiler that are either not applicable for c29clang or are simply not supported.

For example, the __TMS320C28XX__ pre-defined macro symbol indicates support for TI C28x, which does not apply for C29x applications.

cl2000 Macro Symbol

Description / Comments

__TMS320C28XX__

The cl2000 __TMS320C28XX__ macro symbol is not

applicable since c29clang does not support the

TI C28x architecture.

__TMS320C28XX_CLA__

__TMS320C28XX_CLA0__

__TMS320C28XX_CLA1__

__TMS320C28XX_CLA2__

The cl2000 __TMS320C28XX_CLAn__ macro symbols are