Next: Driver, Up: Target Macros
targetm VariableThe target .c file must define the global
targetmvariable which contains pointers to functions and data relating to the target machine. The variable is declared in target.h; target-def.h defines the macroTARGET_INITIALIZERwhich is used to initialize the variable, and macros for the default initializers for elements of the structure. The .c file should override those macros for which the default definition is inappropriate. For example:#include "target.h" #include "target-def.h" /* Initialize the GCC target structure. */ #undef TARGET_COMP_TYPE_ATTRIBUTES #define TARGET_COMP_TYPE_ATTRIBUTES machine_comp_type_attributes struct gcc_target targetm = TARGET_INITIALIZER;
Where a macro should be defined in the .c file in this manner to
form part of the targetm structure, it is documented below as a
“Target Hook” with a prototype. Many macros will change in future
from being defined in the .h file to being part of the
targetm structure.