-fconstant-string-class=@var{class-name} @gol
-fgnu-runtime -fnext-runtime @gol
-fno-nil-receivers @gol
+-fobjc-call-cxx-cdtors @gol
+-fobjc-direct-dispatch @gol
-fobjc-exceptions @gol
+-fobjc-gc @gol
-freplace-objc-classes @gol
-fzero-link @gol
-gen-decls @gol
--Wno-protocol -Wselector -Wundeclared-selector}
+-Wassign-intercept @gol
+-Wno-protocol -Wselector @gol
+-Wstrict-selector-match @gol
+-Wundeclared-selector}
@item Language Independent Options
@xref{Language Independent Options,,Options to Control Diagnostic Messages Formatting}.
@item Warning Options
@xref{Warning Options,,Options to Request or Suppress Warnings}.
@gccoptlist{-fsyntax-only -pedantic -pedantic-errors @gol
--w -Wextra -Wall -Waggregate-return @gol
--Wcast-align -Wcast-qual -Wchar-subscripts -Wcomment @gol
+-w -Wextra -Wall -Waggregate-return -Wno-attributes @gol
+-Wc++-compat -Wcast-align -Wcast-qual -Wchar-subscripts -Wcomment @gol
-Wconversion -Wno-deprecated-declarations @gol
-Wdisabled-optimization -Wno-div-by-zero -Wno-endif-labels @gol
-Werror -Werror-implicit-function-declaration @gol
-fdump-tree-sra@r{[}-@var{n}@r{]} @gol
-fdump-tree-salias @gol
-fdump-tree-fre@r{[}-@var{n}@r{]} @gol
+-fdump-tree-vrp@r{[}-@var{n}@r{]} @gol
-ftree-vectorizer-verbose=@var{n} @gol
-fdump-tree-storeccp@r{[}-@var{n}@r{]} @gol
-feliminate-dwarf2-dups -feliminate-unused-debug-types @gol
-fbranch-target-load-optimize2 -fbtr-bb-exclusive @gol
-fcaller-saves -fcprop-registers -fcse-follow-jumps @gol
-fcse-skip-blocks -fcx-limited-range -fdata-sections @gol
--fdelayed-branch -fdelete-null-pointer-checks @gol
+-fdelayed-branch -fdelete-null-pointer-checks -fearly-inlining @gol
-fexpensive-optimizations -ffast-math -ffloat-store @gol
-fforce-addr -fforce-mem -ffunction-sections @gol
-fgcse -fgcse-lm -fgcse-sm -fgcse-las -fgcse-after-reload @gol
-ftree-dominator-opts -ftree-dse -ftree-copyrename -ftree-sink @gol
-ftree-ch -ftree-sra -ftree-ter -ftree-lrs -ftree-fre -ftree-vectorize @gol
-ftree-salias -fweb @gol
--ftree-copy-prop -ftree-store-ccp -ftree-store-copy-prop @gol
+-ftree-copy-prop -ftree-store-ccp -ftree-store-copy-prop -fwhole-program @gol
--param @var{name}=@var{value}
-O -O0 -O1 -O2 -O3 -Os}
@emph{Blackfin Options}
@gccoptlist{-momit-leaf-frame-pointer -mno-omit-leaf-frame-pointer -mcsync @gol
-mno-csync -mlow-64k -mno-low64k -mid-shared-library @gol
--mno-id-shared-library -mshared-library-id=@var{n} @gol}
+-mno-id-shared-library -mshared-library-id=@var{n} @gol
+-mlong-calls -mno-long-calls}
@emph{CRIS Options}
@gccoptlist{-mcpu=@var{cpu} -march=@var{cpu} -mtune=@var{cpu} @gol
-mstrict-align -mno-strict-align -mrelocatable @gol
-mno-relocatable -mrelocatable-lib -mno-relocatable-lib @gol
-mtoc -mno-toc -mlittle -mlittle-endian -mbig -mbig-endian @gol
--mdynamic-no-pic @gol
+-mdynamic-no-pic -maltivec -mswdiv @gol
-mprioritize-restricted-insns=@var{priority} @gol
-msched-costly-dep=@var{dependence_type} @gol
-minsert-sched-nops=@var{scheme} @gol
-mcall-sysv -mcall-netbsd @gol
-maix-struct-return -msvr4-struct-return @gol
--mabi=@var{abi-type} @gol
+-mabi=@var{abi-type} -msecure-plt -mbss-plt @gol
-misel -mno-isel @gol
-misel=yes -misel=no @gol
-mspe -mno-spe @gol
-finhibit-size-directive -finstrument-functions @gol
-fno-common -fno-ident @gol
-fpcc-struct-return -fpic -fPIC -fpie -fPIE @gol
+-fno-jump-tables @gol
-freg-struct-return -fshared-data -fshort-enums @gol
-fshort-double -fshort-wchar @gol
-fverbose-asm -fpack-struct[=@var{n}] -fstack-check @gol
the last two letters must both be literally @samp{x}. Likewise,
@samp{.C} refers to a literal capital C@.
+@item @var{file}.mm
+@itemx @var{file}.M
+Objective-C++ source code which must be preprocessed.
+
+@item @var{file}.mii
+Objective-C++ source code which should not be preprocessed.
+
@item @var{file}.hh
@itemx @var{file}.H
C++ header file to be turned into a precompiled header.
to be used. Currently, this option is only available in conjunction with
the NeXT runtime on Mac OS X 10.3 and later.
+@item -fobjc-call-cxx-cdtors
+@opindex fobjc-call-cxx-cdtors
+For each Objective-C class, check if any of its instance variables is a
+C++ object with a non-trivial default constructor. If so, synthesize a
+special @code{- (id) .cxx_construct} instance method that will run
+non-trivial default constructors on any such instance variables, in order,
+and then return @code{self}. Similarly, check if any instance variable
+is a C++ object with a non-trivial destructor, and if so, synthesize a
+special @code{- (void) .cxx_destruct} method that will run
+all such default destructors, in reverse order.
+
+The @code{- (id) .cxx_construct} and/or @code{- (void) .cxx_destruct} methods
+thusly generated will only operate on instance variables declared in the
+current Objective-C class, and not those inherited from superclasses. It
+is the responsibility of the Objective-C runtime to invoke all such methods
+in an object's inheritance hierarchy. The @code{- (id) .cxx_construct} methods
+will be invoked by the runtime immediately after a new object
+instance is allocated; the @code{- (void) .cxx_destruct} methods will
+be invoked immediately before the runtime deallocates an object instance.
+
+As of this writing, only the NeXT runtime on Mac OS X 10.4 and later has
+support for invoking the @code{- (id) .cxx_construct} and
+@code{- (void) .cxx_destruct} methods.
+
+@item -fobjc-direct-dispatch
+@opindex fobjc-direct-dispatch
+Allow fast jumps to the message dispatcher. On Darwin this is
+accomplished via the comm page.
+
@item -fobjc-exceptions
@opindex fobjc-exceptions
Enable syntactic support for structured exception handling in Objective-C,
@code{@@synchronized} blocks is allowed, and will cause the guarding object
to be unlocked properly.
+@item -fobjc-gc
+@opindex fobjc-gc
+Enable garbage collection (GC) in Objective-C and Objective-C++ programs.
+
@item -freplace-objc-classes
@opindex freplace-objc-classes
Emit a special marker instructing @command{ld(1)} not to statically link in
Dump interface declarations for all classes seen in the source file to a
file named @file{@var{sourcename}.decl}.
+@item -Wassign-intercept
+@opindex Wassign-intercept
+Warn whenever an Objective-C assignment is being intercepted by the
+garbage collector.
+
@item -Wno-protocol
@opindex Wno-protocol
If a class is declared to implement a protocol, a warning is issued for
found during compilation, or because the @option{-fsyntax-only} option is
being used.
+@item -Wstrict-selector-match
+@opindex Wstrict-selector-match
+Warn if multiple methods with differing argument and/or return types are
+found for a given selector when attempting to send a message using this
+selector to a receiver of type @code{id} or @code{Class}. When this flag
+is off (which is the default behavior), the compiler will omit such warnings
+if any differences found are confined to types which share the same size
+and alignment.
+
@item -Wundeclared-selector
@opindex Wundeclared-selector
Warn if a @code{@@selector(@dots{})} expression referring to an
Warn whenever a function call is cast to a non-matching type.
For example, warn if @code{int malloc()} is cast to @code{anything *}.
+@item -Wc++-compat
+Warn about ISO C constructs that are outside of the common subset of
+ISO C and ISO C++, e.g.@: request for implicit conversion from
+@code{void *} to a pointer to non-@code{void} type.
+
@item -Wcast-qual
@opindex Wcast-qual
Warn whenever a pointer is cast so as to remove a type qualifier from
called. (In languages where you can return an array, this also elicits
a warning.)
+@item -Wno-attributes
+@opindex Wno-attributes
+@opindex Wattributes
+Do not warn if an unexpected @code{__attribute__} is used, such as
+unrecognized attributes, function attributes applied to variables,
+etc. This will not stop errors for incorrect use of supported
+attributes.
+
@item -Wstrict-prototypes @r{(C only)}
@opindex Wstrict-prototypes
Warn if a function is declared or defined without specifying the
the basename of the source file. In both cases any suffix is removed
(e.g.@: @file{foo.gcda} for input file @file{dir/foo.c}, or
@file{dir/foo.gcda} for output file specified as @option{-o dir/foo.o}).
+@xref{Cross-profiling}.
@cindex @command{gcov}
@item --coverage
use diff on debugging dumps for compiler invocations with different
options, in particular with and without @option{-g}.
-@item -fdump-translation-unit @r{(C and C++ only)}
-@itemx -fdump-translation-unit-@var{options} @r{(C and C++ only)}
+@item -fdump-translation-unit @r{(C++ only)}
+@itemx -fdump-translation-unit-@var{options} @r{(C++ only)}
@opindex fdump-translation-unit
Dump a representation of the tree structure for the entire translation
unit to a file. The file name is made by appending @file{.tu} to the
Dump each function after applying vectorization of loops. The file name is
made by appending @file{.vect} to the source file name.
+@item vrp
+@opindex fdump-tree-vrp
+Dump each function after Value Range Propagation (VRP). The file name
+is made by appending @file{.vrp} to the source file name.
+
@item all
@opindex fdump-tree-all
Enable all the available tree dumps with the flags provided in this option.
-funit-at-a-time @gol
-falign-functions -falign-jumps @gol
-falign-loops -falign-labels @gol
+-ftree-vrp @gol
-ftree-pre}
Please note the warning under @option{-fgcse} about
Enabled at level @option{-O3}.
+@item -fearly-inlining
+@opindex fearly-inlining
+Inline functions marked by @code{always_inline} and functions whose body seems
+smaller than the function call overhead early before doing
+@option{-fprofile-generate} instrumentation and real inlining pass. Doing so
+makes profiling significantly cheaper and usually inlining faster on programs
+having large chains of nested wrapper functions.
+
+Enabled by default.
+
@item -finline-limit=@var{n}
@opindex finline-limit
By default, GCC limits the size of functions that can be inlined. This flag
parameters controlling inlining.
@emph{Note:} pseudo instruction represents, in this particular context, an
-abstract measurement of function's size. In no way, it represents a count
+abstract measurement of function's size. In no way does it represent a count
of assembly instructions and as such its exact meaning might change from one
release to an another.
@item -ftree-vectorize
Perform loop vectorization on trees.
+@item -ftree-vrp
+Perform Value Range Propagation on trees. This is similar to the
+constant propagation pass, but instead of values, ranges of values are
+propagated. This allows the optimizers to remove unnecessary range
+checks like array bound checks and null pointer checks. This is
+enabled by default at @option{-O2} and higher. Null pointer check
+elimination is only done if @option{-fdelete-null-pointer-checks} is
+enabled.
+
@item -ftracer
@opindex ftracer
Perform tail duplication to enlarge superblock size. This transformation
@item
@emph{unit-at-a-time} mode removes unreferenced static variables
-and functions are removed. This may result in undefined references
+and functions. This may result in undefined references
when an @code{asm} statement refers directly to variables or functions
that are otherwise unused. In that case either the variable/function
shall be listed as an operand of the @code{asm} statement operand or,
on targets where the default format for debugging information supports
variable tracking.
+@item -fwhole-program
+@opindex fwhole-program
+Assume that the current compilation unit represents whole program being
+compiled. All public functions and variables with the exception of @code{main}
+and those merged by attribute @code{externally_visible} become static functions
+and in a affect gets more aggressively optimized by interprocedural optimizers.
+While this option is equivalent to proper use of @code{static} keyword for
+programs consisting of single file, in combination with option
+@option{--combine} this flag can be used to compile most of smaller scale C
+programs since the functions and variables become local for the whole combined
+compilation unit, not for the single source file itself.
+
+
@item -fno-cprop-registers
@opindex fno-cprop-registers
After register allocation and post-register allocation instruction splitting,
The default is @option{-fmath-errno}.
+On Darwin systems, the math library never sets @code{errno}. There is therefore
+no reason for the compiler to consider the possibility that it might,
+and @option{-fno-math-errno} is the default.
+
@item -funsafe-math-optimizations
@opindex funsafe-math-optimizations
Allow optimizations for floating-point arithmetic that (a) assume
options, usually for compatibility with other compilers on the same
platform.
-These options are defined by the macro @code{TARGET_SWITCHES} in the
-machine description. The default for the options is also defined by
-that macro, which enables you to change the defaults.
-
@c This list is ordered alphanumerically by subsection name.
@c It should be the same order and spelling as these options are listed
@c in Machine Dependent Options
compiled. Specifying a value of 0 will generate more compact code, specifying
other values will force the allocation of that number to the current
library but is no more space or time efficient than omitting this option.
+
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Tells the compiler to perform function calls by first loading the
+address of the function into a register and then performing a subroutine
+call on this register. This switch is needed if the target function
+will lie outside of the 24 bit addressing range of the offset based
+version of subroutine call instruction.
+
+This feature is not enabled by default. Specifying
+@option{-mno-long-calls} will restore the default behavior. Note these
+switches have no effect on how the compiler generates code to handle
+function calls via function pointers.
@end table
@node CRIS Options
@itemx -mno-mips16
@opindex mips16
@opindex mno-mips16
-Use (do not use) the MIPS16 ISA@.
+Generate (do not generate) MIPS16 code. If GCC is targetting a
+MIPS32 or MIPS64 architecture, it will make use of the MIPS16e ASE@.
@item -mabi=32
@itemx -mabi=o64
architecture, registers, and mnemonics set by @option{-mcpu}, but the
scheduling parameters set by @option{-mtune}.
+@item -mswdiv
+@itemx -mno-swdiv
+@opindex mswdiv
+@opindex mno-swdiv
+Generate code to compute division as reciprocal estimate and iterative
+refinement, creating opportunities for increased throughput. This
+feature requires: optional PowerPC Graphics instruction set for single
+precision and FRE instruction for double precision, assuming divides
+cannot generate user-visible traps, and the domain values not include
+Infinities, denormals or zero denominator.
+
@item -maltivec
@itemx -mno-altivec
@opindex maltivec
@opindex mabi=no-spe
Disable Booke SPE ABI extensions for the current ABI@.
+@item -msecure-plt
+@opindex msecure-plt
+Generate code that allows ld and ld.so to build executables and shared
+libraries with non-exec .plt and .got sections. This is a PowerPC
+32-bit SYSV ABI option.
+
+@item -mbss-plt
+@opindex mbss-plt
+Generate code that uses a BSS .plt section that ld.so fills in, and
+requires .plt and .got sections that are both writable and executable.
+This is a PowerPC 32-bit SYSV ABI option.
+
@item -misel
@itemx -mno-isel
@opindex misel
@opindex mapp-regs
Specify @option{-mapp-regs} to generate output using the global registers
2 through 4, which the SPARC SVR4 ABI reserves for applications. This
-is the default, except on Solaris.
+is the default.
To be fully SVR4 ABI compliant at the cost of some performance loss,
specify @option{-mno-app-regs}. You should compile libraries and system
Usually these options are used when @option{-pie} GCC option will be
used during linking.
+@item -fno-jump-tables
+@opindex fno-jump-tables
+Do not use jump tables for switch statements even where it would be
+more efficient than other code generation strategies. This option is
+of use in conjunction with @option{-fpic} or @option{-fPIC} for
+building code which forms part of a dynamic linker and cannot
+reference the address of a jump table. On some targets, jump tables
+do not require a GOT and this option is not needed.
+
@item -ffixed-@var{reg}
@opindex ffixed
Treat the register named @var{reg} as a fixed register; generated code
@samp{#pragma GCC visibility} of use. This works by you enclosing
the declarations you wish to set visibility for with (for example)
@samp{#pragma GCC visibility push(hidden)} and
-@samp{#pragma GCC visibility pop}. These can be nested up to sixteen
-times. Bear in mind that symbol visibility should be viewed @strong{as
+@samp{#pragma GCC visibility pop}.
+Bear in mind that symbol visibility should be viewed @strong{as
part of the API interface contract} and thus all new code should
always specify visibility when it is not the default ie; declarations
only for use within the local DSO should @strong{always} be marked explicitly
`precompile' a header file; then, if builds can use the precompiled
header file they will be much faster.
-@strong{Caution:} There are a few known situations where GCC will
-crash when trying to use a precompiled header. If you have trouble
-with a precompiled header, you should remove the precompiled header
-and compile without it. In addition, please use GCC's on-line
-defect-tracking system to report any problems you encounter with
-precompiled headers. @xref{Bugs}.
-
To create a precompiled header file, simply compile it as you would any
other file, if necessary using the @option{-x} option to make the driver
treat it as a C or C++ header file. You will probably want to use a
compilation.
@item
-The precompiled header file must be produced by the same compiler
-version and configuration as the current compilation is using.
-The easiest way to guarantee this is to use the same compiler binary
-for creating and using precompiled headers.
+The precompiled header file must have been produced by the same compiler
+binary as the current compilation is using.
@item
Any macros defined before the precompiled header is included must
is to use exactly the same options when generating and using the
precompiled header. The following are known to be safe:
-@gccoptlist{-fpreprocessed -pedantic-errors}
+@gccoptlist{-fpreprocessed
+-fsched-interblock -fsched-spec -fsched-spec-load -fsched-spec-load-dangerous
+-fsched-verbose=<number> -fschedule-insns
+-pedantic-errors}
@end itemize
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