Using and Porting GNU CC

Chapter 16: 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.

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.