(gcc.info)Target Macros

Target Description Macros
*************************

   In addition to the file `MACHINE.md', a machine description includes
a C header file conventionally given the name `MACHINE.h'.  This header
file defines numerous macros that convey the information about the
target machine that does not fit into the scheme of the `.md' file.
The file `tm.h' should be a link to `MACHINE.h'.  The header file
`config.h' includes `tm.h' and most compiler source files include
`config.h'.



* Driver
Controlling how the driver runs the compilation passes.
* Run-time Target
Defining `-m' options like `-m68000' and `-m68020'.
* Storage Layout
Defining sizes and alignments of data.
* Type Layout
Defining sizes and properties of basic user data types.
* Registers
Naming and describing the hardware registers.
* Register Classes
Defining the classes of hardware registers.
* Stack and Calling
Defining which way the stack grows and by how much.
* Varargs
Defining the varargs macros.
* Trampolines
Code set up at run time to enter a nested function.
* Library Calls
Controlling how library routines are implicitly called.
* Addressing Modes
Defining addressing modes valid for memory operands.
* Condition Code
Defining how insns update the condition code.
* Costs
Defining relative costs of different operations.
* Sections
Dividing storage into text, data, and other sections.
* PIC
Macros for position independent code.
* Assembler Format
Defining how to write insns and pseudo-ops to output.
* Debugging Info
Defining the format of debugging output.
* Cross-compilation
Handling floating point for cross-compilers.
* Misc
Everything else.