diff options
Diffstat (limited to 'gcc-4.4.3/gcc/doc/invoke.texi')
| -rw-r--r-- | gcc-4.4.3/gcc/doc/invoke.texi | 204 |
1 files changed, 160 insertions, 44 deletions
diff --git a/gcc-4.4.3/gcc/doc/invoke.texi b/gcc-4.4.3/gcc/doc/invoke.texi index 8f7e654c8..f35cee8b1 100644 --- a/gcc-4.4.3/gcc/doc/invoke.texi +++ b/gcc-4.4.3/gcc/doc/invoke.texi @@ -245,16 +245,16 @@ Objective-C and Objective-C++ Dialects}. -Wno-int-to-pointer-cast -Wno-invalid-offsetof @gol -Winvalid-pch -Wlarger-than=@var{len} -Wunsafe-loop-optimizations @gol -Wlogical-op -Wlong-long @gol --Wmain -Wmissing-braces -Wmissing-field-initializers @gol +-Wmain -Wmaybe-uninitialized -Wmissing-braces -Wmissing-field-initializers @gol -Wmissing-format-attribute -Wmissing-include-dirs @gol -Wmissing-noreturn -Wno-mudflap @gol --Wno-multichar -Wnonnull -Wno-overflow -Wnull-conversion @gol +-Wno-multichar -Wnonnull -Wno-overflow -Wconversion-null @gol -Woverlength-strings -Wpacked -Wpacked-bitfield-compat -Wpadded @gol -Wparentheses -Wpedantic-ms-format -Wno-pedantic-ms-format @gol -Wpointer-arith -Wno-pointer-to-int-cast @gol -Wreal-conversion -Wredundant-decls @gol --Wreturn-type -Wripa-opt-mismatch -Wself-assign -Wsequence-point @gol --Wshadow -Wshadow-compatible-local -Wshadow-local @gol +-Wreturn-type -Wripa-opt-mismatch -Wself-assign -Wself-assign-non-pod @gol +-Wsequence-point -Wshadow -Wshadow-compatible-local -Wshadow-local @gol -Wsign-compare -Wsign-conversion -Wstack-protector @gol -Wstrict-aliasing -Wstrict-aliasing=n @gol -Wstrict-overflow -Wstrict-overflow=@var{n} @gol @@ -329,13 +329,15 @@ Objective-C and Objective-C++ Dialects}. -falign-labels[=@var{n}] -falign-loops[=@var{n}] -fassociative-math @gol -fauto-inc-dec -fbranch-probabilities -fbranch-target-load-optimize @gol -fbranch-target-load-optimize2 -fbtr-bb-exclusive -fcaller-saves @gol --fcheck-data-deps -fconserve-stack -fcprop-registers -fcrossjumping @gol +-fcgraph-section -fcheck-data-deps @gol +-fconserve-stack -fcprop-registers -fcrossjumping @gol -fcse-follow-jumps -fcse-skip-blocks -fcx-fortran-rules -fcx-limited-range @gol -fdata-sections -fdce -fdce @gol -fdelayed-branch -fdelete-null-pointer-checks -fdse -fdse @gol -fearly-inlining -fexpensive-optimizations -ffast-math @gol -ffinite-math-only -ffloat-store -fforward-propagate @gol --ffunction-sections -fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol +-ffunction-sections -ffvpt -ffvpt-functions=@var{ffvptfunctions} -fgcse @gol +-fgcse-after-reload -fgcse-las -fgcse-lm @gol -fgcse-sm -fif-conversion -fif-conversion2 -findirect-inlining @gol -finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol -finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol @@ -355,14 +357,16 @@ Objective-C and Objective-C++ Dialects}. -fomit-frame-pointer -foptimize-register-move -foptimize-sibling-calls @gol -fpeel-loops -fpredictive-commoning -fprefetch-loop-arrays @gol -fprofile-correction -fprofile-dir=@var{path} -fprofile-generate @gol --fprofile-generate=@var{path} @gol +-fprofile-generate=@var{path} -fprofile-generate-sampling @gol -fprofile-use -fprofile-use=@var{path} -fprofile-values @gol +-fpmu-profile-generate=@var{pmuoption} @gol +-fpmu-profile-use=@var{pmuoption} @gol -freciprocal-math -fregmove -frename-registers -freorder-blocks @gol -freorder-blocks-and-partition -freorder-functions @gol -frerun-cse-after-loop -freschedule-modulo-scheduled-loops @gol --fripa -fripa-disallow-asm-modules @gol --fripa-disallow-opt-mismatch -fripa-verbose -frounding-math @gol --fsample-profile -fsample-profile-aggregate-using @gol +-fripa -fripa-disallow-asm-modules -fripa-disallow-opt-mismatch @gol +-fripa-no-promote-always-inline-func -fripa-verbose @gol +-frounding-math -fsample-profile -fsample-profile-aggregate-using @gol -fsample-profile-use-entry -fsched2-use-superblocks @gol -fsched2-use-traces -fsched-spec-load -fsched-spec-load-dangerous @gol -fsched-stalled-insns-dep[=@var{n}] -fsched-stalled-insns[=@var{n}] @gol @@ -583,17 +587,17 @@ Objective-C and Objective-C++ Dialects}. -mno-wide-multiply -mrtd -malign-double @gol -mpreferred-stack-boundary=@var{num} -mincoming-stack-boundary=@var{num} --mcld -mcx16 -msahf -mrecip @gol +-mcld -mcx16 -msahf -mmovbe -mrecip @gol -mmmx -msse -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -msse4 -mavx @gol -maes -mpclmul @gol --msse4a -m3dnow -mpopcnt -mabm -msse5 @gol +-msse4a -m3dnow -mpopcnt -mabm -msse5 -mlwp @gol -mthreads -mno-align-stringops -minline-all-stringops @gol -minline-stringops-dynamically -minline-compares @gol -mstringop-strategy=@var{alg} -mpush-args -maccumulate-outgoing-args @gol -m128bit-long-double -m96bit-long-double -mregparm=@var{num} -msseregparm @gol -mveclibabi=@var{type} -mpc32 -mpc64 -mpc80 -mstackrealign @gol -momit-leaf-frame-pointer -mno-red-zone -mno-tls-direct-seg-refs @gol --mcmodel=@var{code-model} @gol +-mcmodel=@var{code-model} -mabi=@var{name} @gol -m32 -m64 -mlarge-data-threshold=@var{num} @gol -mfused-madd -mno-fused-madd -msse2avx} @@ -2786,6 +2790,7 @@ Options} and @ref{Objective-C and Objective-C++ Dialect Options}. -Wcomment @gol -Wformat @gol -Wmain @r{(only for C/ObjC and unless} @option{-ffreestanding}@r{)} @gol +-Wmaybe-uninitialized @gol -Wmissing-braces @gol -Wnonnull @gol -Wparentheses @gol @@ -2834,6 +2839,7 @@ name is still supported, but the newer name is more descriptive.) -Wsign-compare @gol -Wtype-limits @gol -Wuninitialized @gol +-Wmaybe-uninitialized @gol -Wunused-parameter @r{(only with} @option{-Wunused} @r{or} @option{-Wall}@r{)} @gol } @@ -2978,7 +2984,7 @@ Enable @option{-Wformat} plus format checks not included in @option{-Wformat}. Currently equivalent to @samp{-Wformat -Wformat-nonliteral -Wformat-security -Wformat-y2k}. -@item -Wnonnull @r{(C and Objective-C only)} +@item -Wnonnull @r{(C, C++, Objective-C, and Objective-C++ only)} @opindex Wnonnull @opindex Wno-nonnull Warn about passing a null pointer for arguments marked as @@ -3193,12 +3199,22 @@ void func() @end group @end smallexample +In C++ it will not warn on self-assignment of non-POD variables unless +@option{-Wself-assign-non-pod} is also enabled. + +@item -Wself-assign-non-pod +@opindex Wself-assign-non-pod +@opindex Wno-self-assign-non-pod +Warn about self-assignment of non-POD variables. This is a C++-specific +warning and only effective when @option{-Wself-assign} is enabled. + There are cases where self-assignment might be intentional. For example, -a C++ programmers might write code to test whether an overloaded +a C++ programmer might write code to test whether an overloaded @code{operator=} works when the same object is assigned to itself. -One way to work around the self-assign warning in such case is using -the functional form @code{object.operator=(object)} instead of the -assignment form @code{object = object}, as shown in the following example. +One way to work around the self-assign warning in such cases when this flag +is enabled is using the functional form @code{object.operator=(object)} +instead of the assignment form @code{object = object}, as shown in the +following example. @smallexample @group @@ -3358,8 +3374,15 @@ to compute a value that itself is never used, because such computations may be deleted by data flow analysis before the warnings are printed. -These warnings are made optional because GCC is not smart -enough to see all the reasons why the code might be correct +@item -Wmaybe-uninitialized +@opindex Wmaybe-uninitialized +@opindex Wno-maybe-uninitialized +For an automatic variable, if there exists a path from the function +entry to a use of the variable that is initialized, but there exist +some other paths the variable is not initialized, the compiler will +emit a warning if it can not prove the uninitialized paths do not +happen at runtime. These warnings are made optional because GCC is +not smart enough to see all the reasons why the code might be correct despite appearing to have an error. Here is one example of how this can happen: @@ -3382,20 +3405,9 @@ this can happen: @noindent If the value of @code{y} is always 1, 2 or 3, then @code{x} is -always initialized, but GCC doesn't know this. Here is -another common case: - -@smallexample -@{ - int save_y; - if (change_y) save_y = y, y = new_y; - @dots{} - if (change_y) y = save_y; -@} -@end smallexample - -@noindent -This has no bug because @code{save_y} is used only if it is set. +always initialized, but GCC doesn't know this. To suppress the +warning, the user needs to provide a default case with assert(0) or +similar code. @cindex @code{longjmp} warnings This option also warns when a non-volatile automatic variable might be @@ -3857,9 +3869,9 @@ to them. Warnings about conversions between signed and unsigned integers are disabled by default in C++ unless @option{-Wsign-conversion} is explicitly enabled. -@item -Wnull-conversion -@opindex Wnull-conversion -@opindex Wno-null-conversion +@item -Wconversion-null +@opindex Wconversion-null +@opindex Wno-conversion-null Warn about peculiar, but valid, conversions from/to @code{NULL}. This includes converting @code{NULL} to non-pointer type and converting the boolean value @code{false} to @code{NULL}. This warning @@ -6975,6 +6987,20 @@ The following options are enabled: @code{-fprofile-arcs}, @code{-fprofile-values If @var{path} is specified, GCC will look at the @var{path} to find the profile feedback data files. See @option{-fprofile-dir}. +@item -fprofile-generate-sampling +@opindex -fprofile-generate-sampling + +Enable sampling for instrumented binaries. Instead of recording every event, +record only every N-th event, where N (the sampling rate) can be set either +at compile time using +@option{--param profile-generate-sampling-rate=@var{value}}, or +at execution start time through environment variable @samp{GCOV_SAMPLING_RATE}. + +At this time sampling applies only to branch counters. A sampling rate of 100 +decreases instrumentated binary slowdown from up to 20x for heavily threaded +applications down to around 2x. @option{-fprofile-correction} is always +needed with sampling. + @item -fprofile-use @itemx -fprofile-use=@var{path} @opindex fprofile-use @@ -6992,6 +7018,35 @@ code. If @var{path} is specified, GCC will look at the @var{path} to find the profile feedback data files. See @option{-fprofile-dir}. +@item -fpmu-profile-generate=@var{pmuoption} +@opindex fpmu-profile-generate + +Enable performance monitoring unit (PMU) profiling. This collects +hardware counter data corresponding to @var{pmuoption}. Currently +only @var{load-latency} and @var{branch-mispredict} are supported +using pfmon tool. You must use @option{-fpmu-profile-generate} both +when compiling and when linking your program. This PMU profile data +may later be used by the compiler during optimizations as well can be +displayed using coverage tool gcov. The params variable +"pmu_profile_n_addresses" can be used to restrict PMU data collection +to only this many addresses. + +@item -fpmu-profile-use=@var{pmuoption} +@opindex fpmu-profile-use + +Enable performance monitoring unit (PMU) profiling based +optimizations. Currently only @var{load-latency} and +@var{branch-mispredict} are supported. + +@item -fcgraph-section +@opindex fcgraph-section +Emit call graph edge profile counts in .note.callgraph.text sections. This is +used in conjunction with @option{-fprofile-use}. A new .note.callgraph.text +section is created for each function. This section lists every callee and the +number of times it is called. The params variable +"note-cgraph-section-edge-threshold" can be used to only list edges above a +certain threshold. + @item -fripa @opindex fripa Perform dynamic inter-procedural analysis. This is used in conjunction with @@ -7021,6 +7076,10 @@ ignored for this comparison. Enable printing of verbose information about dynamic inter-procedural optimizations. This is used in conjunction with the @option{-fripa}. +@item -fripa-no-promote-always-inline-func +@opindex fripa-no-promote-always-inline-func +Do not promote static functions with always inline attribute in LIPO compilation. + @item -fsample-profile @itemx -fsample-profile=@var{path} @opindex fsample-profile @@ -7293,6 +7352,23 @@ and actually performs the optimizations based on them. Currently the optimizations include specialization of division operation using the knowledge about the value of the denominator. +@item -ffvpt +@opindex ffvpt +If combined with @option{-fvpt and -ffvpt_functions}, it instructs the +compiler to add a code to gather information about math library calls. + +With @option{-fbranch-probabilities}, it reads back the data gathered +and actually performs the optimizations based on them. +Currently the optimizations include specialization of function calls +using precalculated values of common inputs. + +@item -ffvpt-functions=@var{ffvptfunctions} +@opindex ffvpt +This options takes a comma separated list of math functions to be +profiled/optimized by @option{-ffvpt}. The special name ``all'' can be +used to specify all supported math functions. Currently, exp, log, +pow, and sqrt are supported. + @item -frename-registers @opindex frename-registers Attempt to avoid false dependencies in scheduled code by making use @@ -7401,6 +7477,11 @@ If a guard check fails, an error message is printed and the program exits. @opindex fstack-protector-all Like @option{-fstack-protector} except that all functions are protected. +NOTE: When --enable-esp this option is enabled by default +for C, C++, ObjC, ObjC++, if neither @option{-fno-stack-protector} +or @option{-nostdlib} or @option{-nodefaultlibs} or +@option{-fstack-protector} are found. + @item -fsection-anchors @opindex fsection-anchors Try to reduce the number of symbolic address calculations by using @@ -8138,6 +8219,15 @@ attributed to it, it will be assigned a weight of 0 with high confidence. This parameter is only useful when using @option{-fsample-profile}. +@item max-lipo-mem +When importing auxiliary modules during profile-use, check current +memory consumption after parsing each auxiliary module. If it exceeds +this limit (specified in kb), don't import any more auxiliary modules. +Specifying a value of 0 means don't enforce this limit. This parameter +is only useful when using @option{-fprofile-use} and @option{-fripa}. + +@item profile-generate-sampling-rate +Set the sampling rate with @option{-fprofile-generate-sampling}. @end table @end table @@ -8321,6 +8411,12 @@ For predictable results, you must also specify the same set of options that were used to generate code (@option{-fpie}, @option{-fPIE}, or model suboptions) when you specify this option. +NOTE: When --enable-esp this option is enabled by default +for C, C++, ObjC, ObjC++, if neither @option{-fno-pie} or @option{-fno-PIE} +or @option{-fno-pic} or @option{-fno-PIC} or @option{-nostdlib} or +@option{-nostartfiles} or @option{-shared} or @option{-pg} or @option{-p} +are found. + @item -rdynamic @opindex rdynamic Pass the flag @option{-export-dynamic} to the ELF linker, on targets @@ -9354,11 +9450,6 @@ instructions, but still uses the soft-float calling conventions. @samp{hard} allows generation of floating-point instructions and uses FPU-specific calling conventions. -Using @option{-mfloat-abi=hard} with VFP coprocessors is not supported. -Use @option{-mfloat-abi=softfp} with the appropriate @option{-mfpu} option -to allow the compiler to generate code that makes use of the hardware -floating-point capabilities for these CPUs. - The default depends on the specific target configuration. Note that the hard-float and soft-float ABIs are not link-compatible; you must compile your entire program with the same ABI, and link with a @@ -11342,6 +11433,9 @@ SSE2 and SSE3 instruction set support. @item core2 Intel Core2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3 instruction set support. +@item atom +Intel Atom CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3 +instruction set support. @item k6 AMD K6 CPU with MMX instruction set support. @item k6-2, k6-3 @@ -11677,6 +11771,8 @@ preferred alignment to @option{-mpreferred-stack-boundary=2}. @itemx -mno-sse4a @itemx -msse5 @itemx -mno-sse5 +@itemx -mlwp +@itemx -mno-lwp @itemx -m3dnow @itemx -mno-3dnow @itemx -mpopcnt @@ -11690,8 +11786,8 @@ preferred alignment to @option{-mpreferred-stack-boundary=2}. @opindex m3dnow @opindex mno-3dnow These switches enable or disable the use of instructions in the MMX, -SSE, SSE2, SSE3, SSSE3, SSE4.1, AVX, AES, PCLMUL, SSE4A, SSE5, ABM or -3DNow!@: extended instruction sets. +SSE, SSE2, SSE3, SSSE3, SSE4.1, AVX, AES, PCLMUL, SSE4A, SSE5, LWP, +ABM or 3DNow!@: extended instruction sets. These extensions are also available as built-in functions: see @ref{X86 Built-in Functions}, for details of the functions enabled and disabled by these switches. @@ -11741,6 +11837,11 @@ SAHF are load and store instructions, respectively, for certain status flags. In 64-bit mode, SAHF instruction is used to optimize @code{fmod}, @code{drem} or @code{remainder} built-in functions: see @ref{Other Builtins} for details. +@item -mmovbe +@opindex mmovbe +This option will enable GCC to use movbe instruction to implement +@code{__builtin_bswap32} and @code{__builtin_bswap64}. + @item -mrecip @opindex mrecip This option will enable GCC to use RCPSS and RSQRTSS instructions (and their @@ -11777,6 +11878,16 @@ when @option{-mveclibabi=acml} is used. Both @option{-ftree-vectorize} and @option{-funsafe-math-optimizations} have to be enabled. A SVML or ACML ABI compatible library will have to be specified at link time. +@item -mabi=@var{name} +@opindex mabi +Generate code for the specified calling convention. Permissible values +are: @samp{sysv} for the ABI used on GNU/Linux and other systems and +@samp{ms} for the Microsoft ABI. The default is to use the Microsoft +ABI when targeting Windows. On all other systems, the default is the +SYSV ABI. You can control this behavior for a specific function by +using the function attribute @samp{ms_abi}/@samp{sysv_abi}. +@xref{Function Attributes}. + @item -mpush-args @itemx -mno-push-args @opindex mpush-args @@ -16278,6 +16389,11 @@ used during linking. @code{__pie__} and @code{__PIE__}. The macros have the value 1 for @option{-fpie} and 2 for @option{-fPIE}. +NOTE: When --enable-esp this option is enabled by default +for C, C++, ObjC, ObjC++, if neither @option{-fno-pie} or @option{-fno-PIE} +or @option{-fno-pic} or @option{-fno-PIC} or @option{-nostdlib} or +@option{-nostartfiles} or @option{-shared} are found. + @item -fno-jump-tables @opindex fno-jump-tables Do not use jump tables for switch statements even where it would be |