Target Conditionals

When GDB is configured and compiled, various macros are defined or left undefined, to control compilation based on the attributes of the target system. These macros and their meanings are:

ADDITIONAL_OPTIONS

ADDITIONAL_OPTION_CASES

ADDITIONAL_OPTION_HANDLER

ADDITIONAL_OPTION_HELP

These are a set of macros that allow the addition of additional command line options to GDB. They are currently used only for the unsupported i960 Nindy target, and should not be used in any other configuration.

ADDR_BITS_REMOVE (addr)

If a raw machine address includes any bits that are not really part of the address, then define this macro to expand into an expression that zeros those bits in addr. For example, the two low-order bits of a Motorola 88K address may be used by some kernels for their own purposes, since addresses must always be 4-byte aligned, and so are of no use for addressing. Those bits should be filtered out with an expression such as ((addr) & ~3).

BEFORE_MAIN_LOOP_HOOK

Define this to expand into any code that you want to execute before the main loop starts. Although this is not, strictly speaking, a target conditional, that is how it is currently being used. Note that if a configuration were to define it one way for a host and a different way for the target, GDB will probably not compile, let alone run correctly.

BELIEVE_PCC_PROMOTION

coffread.c

BELIEVE_PCC_PROMOTION_TYPE

stabsread.c

BITS_BIG_ENDIAN

Define this if the numbering of bits in the targets does *not* match the endianness of the target byte order. A value of 1 means that the bits are numbered in a big-endian order, 0 means little-endian.

BREAKPOINT

This is the character array initializer for the bit pattern to put into memory where a breakpoint is set. Although it's common to use a trap instruction for a breakpoint, it's not required; for instance, the bit pattern could be an invalid instruction. The breakpoint must be no longer than the shortest instruction of the architecture.

BIG_BREAKPOINT

LITTLE_BREAKPOINT

Similar to BREAKPOINT, but used for bi-endian targets.

CALL_DUMMY

valops.c

CALL_DUMMY_LOCATION

inferior.h

CALL_DUMMY_STACK_ADJUST

valops.c

CANNOT_FETCH_REGISTER (regno)

A C expression that should be nonzero if regno cannot be fetched from an inferior process. This is only relevant if FETCH_INFERIOR_REGISTERS is not defined.

CANNOT_STORE_REGISTER (regno)

A C expression that should be nonzero if regno should not be written to the target. This is often the case for program counters, status words, and other special registers. If this is not defined, GDB will assume that all registers may be written.

CHILL_PRODUCER

GCC_PRODUCER

GPLUS_PRODUCER

LCC_PRODUCER

If defined, these are the producer strings in a DWARF 1 file. All of these have reasonable defaults already.

DO_DEFERRED_STORES

CLEAR_DEFERRED_STORES

Define this to execute any deferred stores of registers into the inferior, and to cancel any deferred stores. Currently only implemented correctly for native Sparc configurations?

CPLUS_MARKER

Define this to expand into the character that G++ uses to distinguish compiler-generated identifiers from programmer-specified identifiers. By default, this expands into '$'. Most System V targets should define this to '.'.

DBX_PARM_SYMBOL_CLASS

Hook for the SYMBOL_CLASS of a parameter when decoding DBX symbol information. In the i960, parameters can be stored as locals or as args, depending on the type of the debug record.

DECR_PC_AFTER_BREAK

Define this to be the amount by which to decrement the PC after the program encounters a breakpoint. This is often the number of bytes in BREAKPOINT, though not always. For most targets this value will be 0.

DECR_PC_AFTER_HW_BREAK

Similarly, for hardware breakpoints.

DISABLE_UNSETTABLE_BREAK addr

If defined, this should evaluate to 1 if addr is in a shared library in which breakpoints cannot be set and so should be disabled.

DO_REGISTERS_INFO

If defined, use this to print the value of a register or all registers.

END_OF_TEXT_DEFAULT

This is an expression that should designate the end of the text section (? FIXME ?)

EXTRACT_RETURN_VALUE

tm-m68k.h

EXTRACT_STRUCT_VALUE_ADDRESS

values.c

EXTRA_FRAME_INFO

If defined, this must be a list of slots that may be inserted into the frame_info structure defined in frame.h.

EXTRA_SYMTAB_INFO

If defined, this must be a list of slots that may be inserted into the symtab structure defined in symtab.h.

FLOAT_INFO

If defined, then the `info float' command will print information about the processor's floating point unit.

FP_REGNUM

The number of the frame pointer register.

FRAMELESS_FUNCTION_INVOCATION

blockframe.c

FRAME_ARGS_ADDRESS_CORRECT

stack.c

FRAME_CHAIN

Given FRAME, return a pointer to the calling frame.

FRAME_CHAIN_COMBINE

blockframe.c

FRAME_CHAIN_VALID

frame.h

FRAME_CHAIN_VALID_ALTERNATE

frame.h

FRAME_FIND_SAVED_REGS

stack.c

FRAME_NUM_ARGS (val, fi)

For the frame described by fi, set val to the number of arguments that are being passed.

FRAME_SPECIFICATION_DYADIC

stack.c

FRAME_SAVED_PC

Given FRAME, return the pc saved there. That is, the return address.

FUNCTION_EPILOGUE_SIZE

For some COFF targets, the x_sym.x_misc.x_fsize field of the function end symbol is 0. For such targets, you must define FUNCTION_EPILOGUE_SIZE to expand into the standard size of a function's epilogue.

GCC_COMPILED_FLAG_SYMBOL

GCC2_COMPILED_FLAG_SYMBOL

If defined, these are the names of the symbols that GDB will look for to detect that GCC compiled the file. The default symbols are gcc_compiled. and gcc2_compiled., respectively. (Currently only defined for the Delta 68.)

GDB_TARGET_IS_HPPA

This determines whether horrible kludge code in dbxread.c and partial-stab.h is used to mangle multiple-symbol-table files from HPPA's. This should all be ripped out, and a scheme like elfread.c used.

GDB_TARGET_IS_MACH386

mach386-xdep.c

GDB_TARGET_IS_SUN3

a68v-xdep.c

GDB_TARGET_IS_SUN386

sun386-xdep.c

GET_LONGJMP_TARGET

For most machines, this is a target-dependent parameter. On the DECstation and the Iris, this is a native-dependent parameter, since <setjmp.h> is needed to define it. This macro determines the target PC address that longjmp() will jump to, assuming that we have just stopped at a longjmp breakpoint. It takes a CORE_ADDR * as argument, and stores the target PC value through this pointer. It examines the current state of the machine as needed.

GET_SAVED_REGISTER

Define this if you need to supply your own definition for the function get_saved_register. Currently this is only done for the a29k.

GR64_REGNUM

Very a29k-specific.

HAVE_REGISTER_WINDOWS

Define this if the target has register windows.

REGISTER_IN_WINDOW_P regnum

Define this to be an expression that is 1 is the given register is in the window.

IBM6000_TARGET

Shows that we are configured for an IBM RS/6000 target. This conditional should be eliminated (FIXME) and replaced by feature-specific macros. It was introduced in haste and we are repenting at leisure.

IEEE_FLOAT

Define this if the target system uses IEEE-format floating point numbers.

IGNORE_SYMBOL type

This seems to be no longer used.

INIT_EXTRA_FRAME_INFO (fromleaf, fci)

If defined, this should be a C expression or statement that fills in the EXTRA_FRAME_INFO slots of the given frame fci.

INIT_EXTRA_SYMTAB_INFO

symfile.c

INIT_FRAME_PC (fromleaf, prev)

This is a C statement that sets the pc of the frame pointed to by prev. [By default...]

INNER_THAN

Define this to be either < if the target's stack grows downward in memory, or > is the stack grows upwards.

IN_SIGTRAMP (pc name)

Define this to return true if the given pc and/or name indicates that the current function is a sigtramp.

SIGTRAMP_START (pc)

SIGTRAMP_END (pc)

Define these to be the start and end address of the sigtramp for the given pc. On machines where the address is just a compile time constant, the macro expansion will typically just ignore the supplied pc.

IN_SOLIB_TRAMPOLINE pc name

Define this to evaluate to nonzero if the program is stopped in the trampoline that connects to a shared library.

IS_TRAPPED_INTERNALVAR name

This is an ugly hook to allow the specification of special actions that should occur as a side-effect of setting the value of a variable internal to GDB. Currently only used by the h8500. Note that this could be either a host or target conditional.

KERNEL_DEBUGGING

tm-ultra3.h

MIPSEL

mips-tdep.c

NEED_TEXT_START_END

Define this if GDB should determine the start and end addresses of the text section. (Seems dubious.)

KERNEL_DEBUGGING

NO_HIF_SUPPORT

(Specific to the a29k.)

NO_SINGLE_STEP

Define this if the target does not support single-stepping. If this is defined, you must supply, in *-tdep.c, the function single_step, which takes a target_signal as argument and returns nothing. It must insert breakpoints at each possible destinations of the next instruction. See sparc-tdep.c and rs6000-tdep.c for examples.

PCC_SOL_BROKEN

(Used only in the Convex target.)

PC_IN_CALL_DUMMY

inferior.h

PC_LOAD_SEGMENT

If defined, print information about the load segment for the program counter. (Defined only for the RS/6000.)

PC_REGNUM

If the program counter is kept in a register, then define this macro to be the number of that register. This need be defined only if TARGET_WRITE_PC is not defined.

NPC_REGNUM

The number of the "next program counter" register, if defined.

NNPC_REGNUM

The number of the "next next program counter" register, if defined. Currently, this is only defined for the Motorola 88K.

PRINT_REGISTER_HOOK (regno)

If defined, this must be a function that prints the contents of the given register to standard output.

PRINT_TYPELESS_INTEGER

This is an obscure substitute for print_longest that seems to have been defined for the Convex target.

PROCESS_LINENUMBER_HOOK

A hook defined for XCOFF reading.

PROLOGUE_FIRSTLINE_OVERLAP

(Only used in unsupported Convex configuration.)

PS_REGNUM

If defined, this is the number of the processor status register. (This definition is only used in generic code when parsing "$ps".)

POP_FRAME

Used in `call_function_by_hand' to remove an artificial stack frame.

PUSH_ARGUMENTS (nargs, args, sp, struct_return, struct_addr)

Define this to push arguments onto the stack for inferior function call.

PUSH_DUMMY_FRAME

Used in `call_function_by_hand' to create an artificial stack frame.

REGISTER_BYTES

The total amount of space needed to store GDB's copy of the machine's register state.

REGISTER_NAMES

Define this to expand into an initializer of an array of strings. Each string is the name of a register. [more detail]

REG_STRUCT_HAS_ADDR (gcc_p, type)

Define this to return 1 if the given type will be passed by pointer rather than directly.

SDB_REG_TO_REGNUM

Define this to convert sdb register numbers into GDB regnums. If not defined, no conversion will be done.

SHIFT_INST_REGS

(Only used for m88k targets.)

SKIP_PROLOGUE

A C statement that advances the PC across any function entry prologue instructions so as to reach "real" code.

SKIP_PROLOGUE_FRAMELESS_P

A C statement that should behave similarly, but that can stop as soon as the function is known to have a frame. If not defined, SKIP_PROLOGUE will be used instead.

SKIP_TRAMPOLINE_CODE (pc)

If the target machine has trampoline code that sits between callers and the functions being called, then define this macro to return a new PC that is at the start of the real function.

SP_REGNUM

Define this to be the number of the register that serves as the stack pointer.

STAB_REG_TO_REGNUM

Define this to convert stab register numbers (as gotten from `r' declarations) into GDB regnums. If not defined, no conversion will be done.

STACK_ALIGN (addr)

Define this to adjust the address to the alignment required for the processor's stack.

STEP_SKIPS_DELAY (addr)

Define this to return true if the address is of an instruction with a delay slot. If a breakpoint has been placed in the instruction's delay slot, GDB will single-step over that instruction before resuming normally. Currently only defined for the Mips.

STORE_RETURN_VALUE (type, valbuf)

A C expression that stores a function return value of type type, where valbuf is the address of the value to be stored.

SUN_FIXED_LBRAC_BUG

(Used only for Sun-3 and Sun-4 targets.)

SYMBOL_RELOADING_DEFAULT

The default value of the `symbol-reloading' variable. (Never defined in current sources.)

TARGET_BYTE_ORDER

The ordering of bytes in the target. This must be defined to be either BIG_ENDIAN or LITTLE_ENDIAN.

TARGET_CHAR_BIT

Number of bits in a char; defaults to 8.

TARGET_COMPLEX_BIT

Number of bits in a complex number; defaults to 2 * TARGET_FLOAT_BIT.

TARGET_DOUBLE_BIT

Number of bits in a double float; defaults to 8 * TARGET_CHAR_BIT.

TARGET_DOUBLE_COMPLEX_BIT

Number of bits in a double complex; defaults to 2 * TARGET_DOUBLE_BIT.

TARGET_FLOAT_BIT

Number of bits in a float; defaults to 4 * TARGET_CHAR_BIT.

TARGET_INT_BIT

Number of bits in an integer; defaults to 4 * TARGET_CHAR_BIT.

TARGET_LONG_BIT

Number of bits in a long integer; defaults to 4 * TARGET_CHAR_BIT.

TARGET_LONG_DOUBLE_BIT

Number of bits in a long double float; defaults to 2 * TARGET_DOUBLE_BIT.

TARGET_LONG_LONG_BIT

Number of bits in a long long integer; defaults to 2 * TARGET_LONG_BIT.

TARGET_PTR_BIT

Number of bits in a pointer; defaults to TARGET_INT_BIT.

TARGET_SHORT_BIT

Number of bits in a short integer; defaults to 2 * TARGET_CHAR_BIT.

TARGET_READ_PC

TARGET_WRITE_PC (val, pid)

TARGET_READ_SP

TARGET_WRITE_SP

TARGET_READ_FP

TARGET_WRITE_FP

These change the behavior of read_pc, write_pc, read_sp, write_sp, read_fp and write_fp. For most targets, these may be left undefined. GDB will call the read and write register functions with the relevant _REGNUM argument. These macros are useful when a target keeps one of these registers in a hard to get at place; for example, part in a segment register and part in an ordinary register.

USE_STRUCT_CONVENTION (gcc_p, type)

If defined, this must be an expression that is nonzero if a value of the given type being returned from a function must have space allocated for it on the stack. gcc_p is true if the function being considered is known to have been compiled by GCC; this is helpful for systems where GCC is known to use different calling convention than other compilers.

VARIABLES_INSIDE_BLOCK (desc, gcc_p)

For dbx-style debugging information, if the compiler puts variable declarations inside LBRAC/RBRAC blocks, this should be defined to be nonzero. desc is the value of n_desc from the N_RBRAC symbol, and gcc_p is true if GDB has noticed the presence of either the GCC_COMPILED_SYMBOL or the GCC2_COMPILED_SYMBOL. By default, this is 0.

OS9K_VARIABLES_INSIDE_BLOCK (desc, gcc_p)

Similarly, for OS/9000. Defaults to 1.

WRS_ORIG

remote-vx.c

test

(Define this to enable testing code in regex.c.)

Motorola M68K target conditionals.

BPT_VECTOR

Define this to be the 4-bit location of the breakpoint trap vector. If not defined, it will default to 0xf.

REMOTE_BPT_VECTOR

Defaults to 1.

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