Red Hat ENTERPRISE LINUX 4 Manual page 123

Chapter 4. GCC Command Options
-fverbose-asm
Put extra commentary information in the generated assembly code to make it more readable. This
option is generally only of use to those who actually need to read the generated assembly code
(perhaps while debugging the compiler itself).
-fno-verbose-asm
comparing two assembler files.
-fpic
Generate position-independent code (PIC) suitable for use in a shared library, if supported for the
target machine. Such code accesses all constant addresses through a global offset table (GOT).
The dynamic loader resolves the GOT entries when the program starts (the dynamic loader is
not part of GCC; it is part of the operating system). If the GOT size for the linked executable
exceeds a machine-specific maximum size, you get an error message from the linker indicating
that does not work; in that case, recompile with
-fpic
on the SPARC and 32k on the m68k and RS/6000. The 386 has no such limit.)
Position-independent code requires special support, and therefore works only on certain ma-
chines. For the 386, GCC supports PIC for System V but not for the Sun 386i. Code generated
for the IBM RS/6000 is always position-independent.
-fPIC
If supported for the target machine, emit position-independent code, suitable for dynamic linking
and avoiding any limit on the size of the global offset table. This option makes a difference on
the m68k and the SPARC.
Position-independent code requires special support, and therefore works only on certain ma-
chines.
-fpie
-fPIE
These options are similar to
only linked into executables. Usually these options are used when
during linking.
-ffixed-
reg
Treat the register named
perhaps as a stack pointer, frame pointer or in some other fixed role).
must be the name of a register. The register names accepted are machine-specific and are
reg
defined in the
REGISTER_NAMES
This flag does not have a negative form, because it specifies a three-way choice.
-fcall-used-
reg
Treat the register named
be allocated for temporaries or variables that do not live across a call. Functions compiled this
way will not save and restore the register
It is an error to used this flag with the frame pointer or stack pointer. Use of this flag for other
registers that have fixed pervasive roles in the machine's execution model will produce disastrous
results.
This flag does not have a negative form, because it specifies a three-way choice.
, the default, causes the extra information to be omitted and is useful when
and
-fpic -fPIC
as a fixed register; generated code should never refer to it (except
reg
macro in the machine description macro file.
as an allocable register that is clobbered by function calls. It may
reg
reg
instead. (These maximums are 8k
-fPIC
, but generated position independent code can be
-pie
.
GCC option will be used
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