компилятор C и C ++ проекта GNU (GNU project C and C++ compiler)
Параметры подробно (Options detail)
GCC Developer
This section describes command-line options that are primarily of
interest to GCC developers, including options to support compiler
testing and investigation of compiler bugs and compile-time
performance problems. This includes options that produce debug
dumps at various points in the compilation; that print statistics
such as memory use and execution time; and that print information
about GCC's configuration, such as where it searches for
libraries. You should rarely need to use any of these options
for ordinary compilation and linking tasks.
Many developer options that cause GCC to dump output to a file
take an optional =filename suffix. You can specify stdout or - to
dump to standard output, and stderr for standard error.
If =filename is omitted, a default dump file name is constructed
by concatenating the base dump file name, a pass number, phase
letter, and pass name. The base dump file name is the name of
output file produced by the compiler if explicitly specified and
not an executable; otherwise it is the source file name. The
pass number is determined by the order passes are registered with
the compiler's pass manager. This is generally the same as the
order of execution, but passes registered by plugins, target-
specific passes, or passes that are otherwise registered late are
numbered higher than the pass named final, even if they are
executed earlier. The phase letter is one of i (inter-procedural
analysis), l (language-specific), r (RTL), or t (tree). The
files are created in the directory of the output file.
-dletters
-fdump-rtl-pass
-fdump-rtl-pass=filename
Says to make debugging dumps during compilation at times
specified by letters. This is used for debugging the RTL-
based passes of the compiler.
Some -dletters switches have different meaning when -E is
used for preprocessing.
Debug dumps can be enabled with a -fdump-rtl switch or some
-d option letters. Here are the possible letters for use in
pass and letters, and their meanings:
-fdump-rtl-alignments
Dump after branch alignments have been computed.
-fdump-rtl-asmcons
Dump after fixing rtl statements that have unsatisfied
in/out constraints.
-fdump-rtl-auto_inc_dec
Dump after auto-inc-dec discovery. This pass is only run
on architectures that have auto inc or auto dec
instructions.
-fdump-rtl-barriers
Dump after cleaning up the barrier instructions.
-fdump-rtl-bbpart
Dump after partitioning hot and cold basic blocks.
-fdump-rtl-bbro
Dump after block reordering.
-fdump-rtl-btl1
-fdump-rtl-btl2
-fdump-rtl-btl1 and -fdump-rtl-btl2 enable dumping after
the two branch target load optimization passes.
-fdump-rtl-bypass
Dump after jump bypassing and control flow optimizations.
-fdump-rtl-combine
Dump after the RTL instruction combination pass.
-fdump-rtl-compgotos
Dump after duplicating the computed gotos.
-fdump-rtl-ce1
-fdump-rtl-ce2
-fdump-rtl-ce3
-fdump-rtl-ce1, -fdump-rtl-ce2, and -fdump-rtl-ce3 enable
dumping after the three if conversion passes.
-fdump-rtl-cprop_hardreg
Dump after hard register copy propagation.
-fdump-rtl-csa
Dump after combining stack adjustments.
-fdump-rtl-cse1
-fdump-rtl-cse2
-fdump-rtl-cse1 and -fdump-rtl-cse2 enable dumping after
the two common subexpression elimination passes.
-fdump-rtl-dce
Dump after the standalone dead code elimination passes.
-fdump-rtl-dbr
Dump after delayed branch scheduling.
-fdump-rtl-dce1
-fdump-rtl-dce2
-fdump-rtl-dce1 and -fdump-rtl-dce2 enable dumping after
the two dead store elimination passes.
-fdump-rtl-eh
Dump after finalization of EH handling code.
-fdump-rtl-eh_ranges
Dump after conversion of EH handling range regions.
-fdump-rtl-expand
Dump after RTL generation.
-fdump-rtl-fwprop1
-fdump-rtl-fwprop2
-fdump-rtl-fwprop1 and -fdump-rtl-fwprop2 enable dumping
after the two forward propagation passes.
-fdump-rtl-gcse1
-fdump-rtl-gcse2
-fdump-rtl-gcse1 and -fdump-rtl-gcse2 enable dumping
after global common subexpression elimination.
-fdump-rtl-init-regs
Dump after the initialization of the registers.
-fdump-rtl-initvals
Dump after the computation of the initial value sets.
-fdump-rtl-into_cfglayout
Dump after converting to cfglayout mode.
-fdump-rtl-ira
Dump after iterated register allocation.
-fdump-rtl-jump
Dump after the second jump optimization.
-fdump-rtl-loop2
-fdump-rtl-loop2 enables dumping after the rtl loop
optimization passes.
-fdump-rtl-mach
Dump after performing the machine dependent
reorganization pass, if that pass exists.
-fdump-rtl-mode_sw
Dump after removing redundant mode switches.
-fdump-rtl-rnreg
Dump after register renumbering.
-fdump-rtl-outof_cfglayout
Dump after converting from cfglayout mode.
-fdump-rtl-peephole2
Dump after the peephole pass.
-fdump-rtl-postreload
Dump after post-reload optimizations.
-fdump-rtl-pro_and_epilogue
Dump after generating the function prologues and
epilogues.
-fdump-rtl-sched1
-fdump-rtl-sched2
-fdump-rtl-sched1 and -fdump-rtl-sched2 enable dumping
after the basic block scheduling passes.
-fdump-rtl-ree
Dump after sign/zero extension elimination.
-fdump-rtl-seqabstr
Dump after common sequence discovery.
-fdump-rtl-shorten
Dump after shortening branches.
-fdump-rtl-sibling
Dump after sibling call optimizations.
-fdump-rtl-split1
-fdump-rtl-split2
-fdump-rtl-split3
-fdump-rtl-split4
-fdump-rtl-split5
These options enable dumping after five rounds of
instruction splitting.
-fdump-rtl-sms
Dump after modulo scheduling. This pass is only run on
some architectures.
-fdump-rtl-stack
Dump after conversion from GCC's "flat register file"
registers to the x87's stack-like registers. This pass
is only run on x86 variants.
-fdump-rtl-subreg1
-fdump-rtl-subreg2
-fdump-rtl-subreg1 and -fdump-rtl-subreg2 enable dumping
after the two subreg expansion passes.
-fdump-rtl-unshare
Dump after all rtl has been unshared.
-fdump-rtl-vartrack
Dump after variable tracking.
-fdump-rtl-vregs
Dump after converting virtual registers to hard
registers.
-fdump-rtl-web
Dump after live range splitting.
-fdump-rtl-regclass
-fdump-rtl-subregs_of_mode_init
-fdump-rtl-subregs_of_mode_finish
-fdump-rtl-dfinit
-fdump-rtl-dfinish
These dumps are defined but always produce empty files.
-da
-fdump-rtl-all
Produce all the dumps listed above.
-dA Annotate the assembler output with miscellaneous
debugging information.
-dD Dump all macro definitions, at the end of preprocessing,
in addition to normal output.
-dH Produce a core dump whenever an error occurs.
-dp Annotate the assembler output with a comment indicating
which pattern and alternative is used. The length and
cost of each instruction are also printed.
-dP Dump the RTL in the assembler output as a comment before
each instruction. Also turns on -dp annotation.
-dx Just generate RTL for a function instead of compiling it.
Usually used with -fdump-rtl-expand.
-fdump-debug
Dump debugging information generated during the debug
generation phase.
-fdump-earlydebug
Dump debugging information generated during the early debug
generation phase.
-fdump-noaddr
When doing debugging dumps, suppress address output. This
makes it more feasible to use diff on debugging dumps for
compiler invocations with different compiler binaries and/or
different text / bss / data / heap / stack / dso start
locations.
-freport-bug
Collect and dump debug information into a temporary file if
an internal compiler error (ICE) occurs.
-fdump-unnumbered
When doing debugging dumps, suppress instruction numbers and
address output. This makes it more feasible to use diff on
debugging dumps for compiler invocations with different
options, in particular with and without -g.
-fdump-unnumbered-links
When doing debugging dumps (see -d option above), suppress
instruction numbers for the links to the previous and next
instructions in a sequence.
-fdump-ipa-switch
-fdump-ipa-switch-options
Control the dumping at various stages of inter-procedural
analysis language tree to a file. The file name is generated
by appending a switch specific suffix to the source file
name, and the file is created in the same directory as the
output file. The following dumps are possible:
all Enables all inter-procedural analysis dumps.
cgraph
Dumps information about call-graph optimization, unused
function removal, and inlining decisions.
inline
Dump after function inlining.
Additionally, the options -optimized, -missed, -note, and
-all can be provided, with the same meaning as for
-fopt-info, defaulting to -optimized.
For example, -fdump-ipa-inline-optimized-missed will emit
information on callsites that were inlined, along with
callsites that were not inlined.
By default, the dump will contain messages about successful
optimizations (equivalent to -optimized) together with low-
level details about the analysis.
-fdump-lang-all
-fdump-lang-switch
-fdump-lang-switch-options
-fdump-lang-switch-options=filename
Control the dumping of language-specific information. The
options and filename portions behave as described in the
-fdump-tree option. The following switch values are
accepted:
all Enable all language-specific dumps.
class
Dump class hierarchy information. Virtual table
information is emitted unless 'slim' is specified. This
option is applicable to C++ only.
raw Dump the raw internal tree data. This option is
applicable to C++ only.
-fdump-passes
Print on stderr the list of optimization passes that are
turned on and off by the current command-line options.
-fdump-statistics-option
Enable and control dumping of pass statistics in a separate
file. The file name is generated by appending a suffix
ending in .statistics to the source file name, and the file
is created in the same directory as the output file. If the
-option form is used, -stats causes counters to be summed
over the whole compilation unit while -details dumps every
event as the passes generate them. The default with no
option is to sum counters for each function compiled.
-fdump-tree-all
-fdump-tree-switch
-fdump-tree-switch-options
-fdump-tree-switch-options=filename
Control the dumping at various stages of processing the
intermediate language tree to a file. If the -options form
is used, options is a list of - separated options which
control the details of the dump. Not all options are
applicable to all dumps; those that are not meaningful are
ignored. The following options are available
address
Print the address of each node. Usually this is not
meaningful as it changes according to the environment and
source file. Its primary use is for tying up a dump file
with a debug environment.
asmname
If "DECL_ASSEMBLER_NAME" has been set for a given decl,
use that in the dump instead of "DECL_NAME". Its primary
use is ease of use working backward from mangled names in
the assembly file.
slim
When dumping front-end intermediate representations,
inhibit dumping of members of a scope or body of a
function merely because that scope has been reached.
Only dump such items when they are directly reachable by
some other path.
When dumping pretty-printed trees, this option inhibits
dumping the bodies of control structures.
When dumping RTL, print the RTL in slim (condensed) form
instead of the default LISP-like representation.
raw Print a raw representation of the tree. By default,
trees are pretty-printed into a C-like representation.
details
Enable more detailed dumps (not honored by every dump
option). Also include information from the optimization
passes.
stats
Enable dumping various statistics about the pass (not
honored by every dump option).
blocks
Enable showing basic block boundaries (disabled in raw
dumps).
graph
For each of the other indicated dump files
(-fdump-rtl-pass), dump a representation of the control
flow graph suitable for viewing with GraphViz to
file.passid.pass.dot. Each function in the file is
pretty-printed as a subgraph, so that GraphViz can render
them all in a single plot.
This option currently only works for RTL dumps, and the
RTL is always dumped in slim form.
vops
Enable showing virtual operands for every statement.
lineno
Enable showing line numbers for statements.
uid Enable showing the unique ID ("DECL_UID") for each
variable.
verbose
Enable showing the tree dump for each statement.
eh Enable showing the EH region number holding each
statement.
scev
Enable showing scalar evolution analysis details.
optimized
Enable showing optimization information (only available
in certain passes).
missed
Enable showing missed optimization information (only
available in certain passes).
note
Enable other detailed optimization information (only
available in certain passes).
all Turn on all options, except raw, slim, verbose and
lineno.
optall
Turn on all optimization options, i.e., optimized,
missed, and note.
To determine what tree dumps are available or find the dump
for a pass of interest follow the steps below.
1. Invoke GCC with -fdump-passes and in the stderr output
look for a code that corresponds to the pass you are
interested in. For example, the codes "tree-evrp",
"tree-vrp1", and "tree-vrp2" correspond to the three
Value Range Propagation passes. The number at the end
distinguishes distinct invocations of the same pass.
2. To enable the creation of the dump file, append the pass
code to the -fdump- option prefix and invoke GCC with it.
For example, to enable the dump from the Early Value
Range Propagation pass, invoke GCC with the
-fdump-tree-evrp option. Optionally, you may specify the
name of the dump file. If you don't specify one, GCC
creates as described below.
3. Find the pass dump in a file whose name is composed of
three components separated by a period: the name of the
source file GCC was invoked to compile, a numeric suffix
indicating the pass number followed by the letter t for
tree passes (and the letter r for RTL passes), and
finally the pass code. For example, the Early VRP pass
dump might be in a file named myfile.c.038t.evrp in the
current working directory. Note that the numeric codes
are not stable and may change from one version of GCC to
another.
-fopt-info
-fopt-info-options
-fopt-info-options=filename
Controls optimization dumps from various optimization passes.
If the -options form is used, options is a list of -
separated option keywords to select the dump details and
optimizations.
The options can be divided into three groups:
1. options describing what kinds of messages should be
emitted,
2. options describing the verbosity of the dump, and
3. options describing which optimizations should be
included.
The options from each group can be freely mixed as they are
non-overlapping. However, in case of any conflicts, the later
options override the earlier options on the command line.
The following options control which kinds of messages should
be emitted:
optimized
Print information when an optimization is successfully
applied. It is up to a pass to decide which information
is relevant. For example, the vectorizer passes print the
source location of loops which are successfully
vectorized.
missed
Print information about missed optimizations. Individual
passes control which information to include in the
output.
note
Print verbose information about optimizations, such as
certain transformations, more detailed messages about
decisions etc.
all Print detailed optimization information. This includes
optimized, missed, and note.
The following option controls the dump verbosity:
internals
By default, only "high-level" messages are emitted. This
option enables additional, more detailed, messages, which
are likely to only be of interest to GCC developers.
One or more of the following option keywords can be used to
describe a group of optimizations:
ipa Enable dumps from all interprocedural optimizations.
loop
Enable dumps from all loop optimizations.
inline
Enable dumps from all inlining optimizations.
omp Enable dumps from all OMP (Offloading and Multi
Processing) optimizations.
vec Enable dumps from all vectorization optimizations.
optall
Enable dumps from all optimizations. This is a superset
of the optimization groups listed above.
If options is omitted, it defaults to optimized-optall, which
means to dump messages about successful optimizations from
all the passes, omitting messages that are treated as
"internals".
If the filename is provided, then the dumps from all the
applicable optimizations are concatenated into the filename.
Otherwise the dump is output onto stderr. Though multiple
-fopt-info options are accepted, only one of them can include
a filename. If other filenames are provided then all but the
first such option are ignored.
Note that the output filename is overwritten in case of
multiple translation units. If a combined output from
multiple translation units is desired, stderr should be used
instead.
In the following example, the optimization info is output to
stderr:
gcc -O3 -fopt-info
This example:
gcc -O3 -fopt-info-missed=missed.all
outputs missed optimization report from all the passes into
missed.all, and this one:
gcc -O2 -ftree-vectorize -fopt-info-vec-missed
prints information about missed optimization opportunities
from vectorization passes on stderr. Note that
-fopt-info-vec-missed is equivalent to -fopt-info-missed-vec.
The order of the optimization group names and message types
listed after -fopt-info does not matter.
As another example,
gcc -O3 -fopt-info-inline-optimized-missed=inline.txt
outputs information about missed optimizations as well as
optimized locations from all the inlining passes into
inline.txt.
Finally, consider:
gcc -fopt-info-vec-missed=vec.miss -fopt-info-loop-optimized=loop.opt
Here the two output filenames vec.miss and loop.opt are in
conflict since only one output file is allowed. In this case,
only the first option takes effect and the subsequent options
are ignored. Thus only vec.miss is produced which contains
dumps from the vectorizer about missed opportunities.
-fsave-optimization-record
Write a SRCFILE.opt-record.json.gz file detailing what
optimizations were performed, for those optimizations that
support -fopt-info.
This option is experimental and the format of the data within
the compressed JSON file is subject to change.
It is roughly equivalent to a machine-readable version of
-fopt-info-all, as a collection of messages with source file,
line number and column number, with the following additional
data for each message:
* the execution count of the code being optimized, along
with metadata about whether this was from actual profile
data, or just an estimate, allowing consumers to
prioritize messages by code hotness,
* the function name of the code being optimized, where
applicable,
* the "inlining chain" for the code being optimized, so
that when a function is inlined into several different
places (which might themselves be inlined), the reader
can distinguish between the copies,
* objects identifying those parts of the message that refer
to expressions, statements or symbol-table nodes, which
of these categories they are, and, when available, their
source code location,
* the GCC pass that emitted the message, and
* the location in GCC's own code from which the message was
emitted
Additionally, some messages are logically nested within other
messages, reflecting implementation details of the
optimization passes.
-fsched-verbose=n
On targets that use instruction scheduling, this option
controls the amount of debugging output the scheduler prints
to the dump files.
For n greater than zero, -fsched-verbose outputs the same
information as -fdump-rtl-sched1 and -fdump-rtl-sched2. For
n greater than one, it also output basic block probabilities,
detailed ready list information and unit/insn info. For n
greater than two, it includes RTL at abort point, control-
flow and regions info. And for n over four, -fsched-verbose
also includes dependence info.
-fenable-kind-pass
-fdisable-kind-pass=range-list
This is a set of options that are used to explicitly
disable/enable optimization passes. These options are
intended for use for debugging GCC. Compiler users should
use regular options for enabling/disabling passes instead.
-fdisable-ipa-pass
Disable IPA pass pass. pass is the pass name. If the
same pass is statically invoked in the compiler multiple
times, the pass name should be appended with a sequential
number starting from 1.
-fdisable-rtl-pass
-fdisable-rtl-pass=range-list
Disable RTL pass pass. pass is the pass name. If the
same pass is statically invoked in the compiler multiple
times, the pass name should be appended with a sequential
number starting from 1. range-list is a comma-separated
list of function ranges or assembler names. Each range
is a number pair separated by a colon. The range is
inclusive in both ends. If the range is trivial, the
number pair can be simplified as a single number. If the
function's call graph node's uid falls within one of the
specified ranges, the pass is disabled for that function.
The uid is shown in the function header of a dump file,
and the pass names can be dumped by using option
-fdump-passes.
-fdisable-tree-pass
-fdisable-tree-pass=range-list
Disable tree pass pass. See -fdisable-rtl for the
description of option arguments.
-fenable-ipa-pass
Enable IPA pass pass. pass is the pass name. If the
same pass is statically invoked in the compiler multiple
times, the pass name should be appended with a sequential
number starting from 1.
-fenable-rtl-pass
-fenable-rtl-pass=range-list
Enable RTL pass pass. See -fdisable-rtl for option
argument description and examples.
-fenable-tree-pass
-fenable-tree-pass=range-list
Enable tree pass pass. See -fdisable-rtl for the
description of option arguments.
Here are some examples showing uses of these options.
# disable ccp1 for all functions
-fdisable-tree-ccp1
# disable complete unroll for function whose cgraph node uid is 1
-fenable-tree-cunroll=1
# disable gcse2 for functions at the following ranges [1,1],
# [300,400], and [400,1000]
# disable gcse2 for functions foo and foo2
-fdisable-rtl-gcse2=foo,foo2
# disable early inlining
-fdisable-tree-einline
# disable ipa inlining
-fdisable-ipa-inline
# enable tree full unroll
-fenable-tree-unroll
-fchecking
-fchecking=n
Enable internal consistency checking. The default depends on
the compiler configuration. -fchecking=2 enables further
internal consistency checking that might affect code
generation.
-frandom-seed=string
This option provides a seed that GCC uses in place of random
numbers in generating certain symbol names that have to be
different in every compiled file. It is also used to place
unique stamps in coverage data files and the object files
that produce them. You can use the -frandom-seed option to
produce reproducibly identical object files.
The string can either be a number (decimal, octal or hex) or
an arbitrary string (in which case it's converted to a number
by computing CRC32).
The string should be different for every file you compile.
-save-temps
-save-temps=cwd
Store the usual "temporary" intermediate files permanently;
place them in the current directory and name them based on
the source file. Thus, compiling foo.c with -c -save-temps
produces files foo.i and foo.s, as well as foo.o. This
creates a preprocessed foo.i output file even though the
compiler now normally uses an integrated preprocessor.
When used in combination with the -x command-line option,
-save-temps is sensible enough to avoid over writing an input
source file with the same extension as an intermediate file.
The corresponding intermediate file may be obtained by
renaming the source file before using -save-temps.
If you invoke GCC in parallel, compiling several different
source files that share a common base name in different
subdirectories or the same source file compiled for multiple
output destinations, it is likely that the different parallel
compilers will interfere with each other, and overwrite the
temporary files. For instance:
gcc -save-temps -o outdir1/foo.o indir1/foo.c&
gcc -save-temps -o outdir2/foo.o indir2/foo.c&
may result in foo.i and foo.o being written to simultaneously
by both compilers.
-save-temps=obj
Store the usual "temporary" intermediate files permanently.
If the -o option is used, the temporary files are based on
the object file. If the -o option is not used, the
-save-temps=obj switch behaves like -save-temps.
For example:
gcc -save-temps=obj -c foo.c
gcc -save-temps=obj -c bar.c -o dir/xbar.o
gcc -save-temps=obj foobar.c -o dir2/yfoobar
creates foo.i, foo.s, dir/xbar.i, dir/xbar.s, dir2/yfoobar.i,
dir2/yfoobar.s, and dir2/yfoobar.o.
-time[=file]
Report the CPU time taken by each subprocess in the
compilation sequence. For C source files, this is the
compiler proper and assembler (plus the linker if linking is
done).
Without the specification of an output file, the output looks
like this:
# cc1 0.12 0.01
# as 0.00 0.01
The first number on each line is the "user time", that is
time spent executing the program itself. The second number
is "system time", time spent executing operating system
routines on behalf of the program. Both numbers are in
seconds.
With the specification of an output file, the output is
appended to the named file, and it looks like this:
0.12 0.01 cc1 <options>
0.00 0.01 as <options>
The "user time" and the "system time" are moved before the
program name, and the options passed to the program are
displayed, so that one can later tell what file was being
compiled, and with which options.
-fdump-final-insns[=file]
Dump the final internal representation (RTL) to file. If the
optional argument is omitted (or if file is "."), the name of
the dump file is determined by appending ".gkd" to the
compilation output file name.
-fcompare-debug[=opts]
If no error occurs during compilation, run the compiler a
second time, adding opts and -fcompare-debug-second to the
arguments passed to the second compilation. Dump the final
internal representation in both compilations, and print an
error if they differ.
If the equal sign is omitted, the default -gtoggle is used.
The environment variable GCC_COMPARE_DEBUG, if defined, non-
empty and nonzero, implicitly enables -fcompare-debug. If
GCC_COMPARE_DEBUG is defined to a string starting with a
dash, then it is used for opts, otherwise the default
-gtoggle is used.
-fcompare-debug=, with the equal sign but without opts, is
equivalent to -fno-compare-debug, which disables the dumping
of the final representation and the second compilation,
preventing even GCC_COMPARE_DEBUG from taking effect.
To verify full coverage during -fcompare-debug testing, set
GCC_COMPARE_DEBUG to say -fcompare-debug-not-overridden,
which GCC rejects as an invalid option in any actual
compilation (rather than preprocessing, assembly or linking).
To get just a warning, setting GCC_COMPARE_DEBUG to
-w%n-fcompare-debug not overridden will do.
-fcompare-debug-second
This option is implicitly passed to the compiler for the
second compilation requested by -fcompare-debug, along with
options to silence warnings, and omitting other options that
would cause the compiler to produce output to files or to
standard output as a side effect. Dump files and preserved
temporary files are renamed so as to contain the ".gk"
additional extension during the second compilation, to avoid
overwriting those generated by the first.
When this option is passed to the compiler driver, it causes
the first compilation to be skipped, which makes it useful
for little other than debugging the compiler proper.
-gtoggle
Turn off generation of debug info, if leaving out this option
generates it, or turn it on at level 2 otherwise. The
position of this argument in the command line does not
matter; it takes effect after all other options are
processed, and it does so only once, no matter how many times
it is given. This is mainly intended to be used with
-fcompare-debug.
-fvar-tracking-assignments-toggle
Toggle -fvar-tracking-assignments, in the same way that
-gtoggle toggles -g.
-Q Makes the compiler print out each function name as it is
compiled, and print some statistics about each pass when it
finishes.
-ftime-report
Makes the compiler print some statistics about the time
consumed by each pass when it finishes.
-ftime-report-details
Record the time consumed by infrastructure parts separately
for each pass.
-fira-verbose=n
Control the verbosity of the dump file for the integrated
register allocator. The default value is 5. If the value n
is greater or equal to 10, the dump output is sent to stderr
using the same format as n minus 10.
-flto-report
Prints a report with internal details on the workings of the
link-time optimizer. The contents of this report vary from
version to version. It is meant to be useful to GCC
developers when processing object files in LTO mode (via
-flto).
Disabled by default.
-flto-report-wpa
Like -flto-report, but only print for the WPA phase of Link
Time Optimization.
-fmem-report
Makes the compiler print some statistics about permanent
memory allocation when it finishes.
-fmem-report-wpa
Makes the compiler print some statistics about permanent
memory allocation for the WPA phase only.
-fpre-ipa-mem-report
-fpost-ipa-mem-report
Makes the compiler print some statistics about permanent
memory allocation before or after interprocedural
optimization.
-fprofile-report
Makes the compiler print some statistics about consistency of
the (estimated) profile and effect of individual passes.
-fstack-usage
Makes the compiler output stack usage information for the
program, on a per-function basis. The filename for the dump
is made by appending .su to the auxname. auxname is
generated from the name of the output file, if explicitly
specified and it is not an executable, otherwise it is the
basename of the source file. An entry is made up of three
fields:
* The name of the function.
* A number of bytes.
* One or more qualifiers: "static", "dynamic", "bounded".
The qualifier "static" means that the function manipulates
the stack statically: a fixed number of bytes are allocated
for the frame on function entry and released on function
exit; no stack adjustments are otherwise made in the
function. The second field is this fixed number of bytes.
The qualifier "dynamic" means that the function manipulates
the stack dynamically: in addition to the static allocation
described above, stack adjustments are made in the body of
the function, for example to push/pop arguments around
function calls. If the qualifier "bounded" is also present,
the amount of these adjustments is bounded at compile time
and the second field is an upper bound of the total amount of
stack used by the function. If it is not present, the amount
of these adjustments is not bounded at compile time and the
second field only represents the bounded part.
-fstats
Emit statistics about front-end processing at the end of the
compilation. This option is supported only by the C++ front
end, and the information is generally only useful to the G++
development team.
-fdbg-cnt-list
Print the name and the counter upper bound for all debug
counters.
-fdbg-cnt=counter-value-list
Set the internal debug counter lower and upper bound.
counter-value-list is a comma-separated list of
name:lower_bound:upper_bound tuples which sets the lower and
the upper bound of each debug counter name. The lower_bound
is optional and is zero initialized if not set. All debug
counters have the initial upper bound of "UINT_MAX"; thus
"dbg_cnt" returns true always unless the upper bound is set
by this option. For example, with
-fdbg-cnt=dce:2:4,tail_call:10, "dbg_cnt(dce)" returns true
only for third and fourth invocation. For
"dbg_cnt(tail_call)" true is returned for first 10
invocations.
-print-file-name=library
Print the full absolute name of the library file library that
would be used when linking---and don't do anything else.
With this option, GCC does not compile or link anything; it
just prints the file name.
-print-multi-directory
Print the directory name corresponding to the multilib
selected by any other switches present in the command line.
This directory is supposed to exist in GCC_EXEC_PREFIX.
-print-multi-lib
Print the mapping from multilib directory names to compiler
switches that enable them. The directory name is separated
from the switches by ;, and each switch starts with an @
instead of the -, without spaces between multiple switches.
This is supposed to ease shell processing.
-print-multi-os-directory
Print the path to OS libraries for the selected multilib,
relative to some lib subdirectory. If OS libraries are
present in the lib subdirectory and no multilibs are used,
this is usually just ., if OS libraries are present in
libsuffix sibling directories this prints e.g. ../lib64,
../lib or ../lib32, or if OS libraries are present in
lib/subdir subdirectories it prints e.g. amd64, sparcv9 or
ev6.
-print-multiarch
Print the path to OS libraries for the selected multiarch,
relative to some lib subdirectory.
-print-prog-name=program
Like -print-file-name, but searches for a program such as
cpp.
-print-libgcc-file-name
Same as -print-file-name=libgcc.a.
This is useful when you use -nostdlib or -nodefaultlibs but
you do want to link with libgcc.a. You can do:
gcc -nostdlib <files>... `gcc -print-libgcc-file-name`
-print-search-dirs
Print the name of the configured installation directory and a
list of program and library directories gcc searches---and
don't do anything else.
This is useful when gcc prints the error message installation
problem, cannot exec cpp0: No such file or directory. To
resolve this you either need to put cpp0 and the other
compiler components where gcc expects to find them, or you
can set the environment variable GCC_EXEC_PREFIX to the
directory where you installed them. Don't forget the
trailing /.
-print-sysroot
Print the target sysroot directory that is used during
compilation. This is the target sysroot specified either at
configure time or using the --sysroot option, possibly with
an extra suffix that depends on compilation options. If no
target sysroot is specified, the option prints nothing.
-print-sysroot-headers-suffix
Print the suffix added to the target sysroot when searching
for headers, or give an error if the compiler is not
configured with such a suffix---and don't do anything else.
-dumpmachine
Print the compiler's target machine (for example,
i686-pc-linux-gnu)---and don't do anything else.
-dumpversion
Print the compiler version (for example, 3.0, 6.3.0 or
7)---and don't do anything else. This is the compiler
version used in filesystem paths and specs. Depending on how
the compiler has been configured it can be just a single
number (major version), two numbers separated by a dot (major
and minor version) or three numbers separated by dots (major,
minor and patchlevel version).
-dumpfullversion
Print the full compiler version---and don't do anything else.
The output is always three numbers separated by dots, major,
minor and patchlevel version.
-dumpspecs
Print the compiler's built-in specs---and don't do anything
else. (This is used when GCC itself is being built.)
