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| <h3 class="section">3.9 Options for Debugging Your Program or GCC</h3> |
| |
| <p><a name="index-options_002c-debugging-476"></a><a name="index-debugging-information-options-477"></a> |
| GCC has various special options that are used for debugging |
| either your program or GCC: |
| |
| <dl> |
| <dt><code>-g</code><dd><a name="index-g-478"></a>Produce debugging information in the operating system's native format |
| (stabs, COFF, XCOFF, or DWARF 2). GDB can work with this debugging |
| information. |
| |
| <p>On most systems that use stabs format, <samp><span class="option">-g</span></samp> enables use of extra |
| debugging information that only GDB can use; this extra information |
| makes debugging work better in GDB but will probably make other debuggers |
| crash or |
| refuse to read the program. If you want to control for certain whether |
| to generate the extra information, use <samp><span class="option">-gstabs+</span></samp>, <samp><span class="option">-gstabs</span></samp>, |
| <samp><span class="option">-gxcoff+</span></samp>, <samp><span class="option">-gxcoff</span></samp>, or <samp><span class="option">-gvms</span></samp> (see below). |
| |
| <p>GCC allows you to use <samp><span class="option">-g</span></samp> with |
| <samp><span class="option">-O</span></samp>. The shortcuts taken by optimized code may occasionally |
| produce surprising results: some variables you declared may not exist |
| at all; flow of control may briefly move where you did not expect it; |
| some statements may not be executed because they compute constant |
| results or their values were already at hand; some statements may |
| execute in different places because they were moved out of loops. |
| |
| <p>Nevertheless it proves possible to debug optimized output. This makes |
| it reasonable to use the optimizer for programs that might have bugs. |
| |
| <p>The following options are useful when GCC is generated with the |
| capability for more than one debugging format. |
| |
| <br><dt><code>-ggdb</code><dd><a name="index-ggdb-479"></a>Produce debugging information for use by GDB. This means to use the |
| most expressive format available (DWARF 2, stabs, or the native format |
| if neither of those are supported), including GDB extensions if at all |
| possible. |
| |
| <br><dt><code>-gstabs</code><dd><a name="index-gstabs-480"></a>Produce debugging information in stabs format (if that is supported), |
| without GDB extensions. This is the format used by DBX on most BSD |
| systems. On MIPS, Alpha and System V Release 4 systems this option |
| produces stabs debugging output which is not understood by DBX or SDB. |
| On System V Release 4 systems this option requires the GNU assembler. |
| |
| <br><dt><code>-feliminate-unused-debug-symbols</code><dd><a name="index-feliminate_002dunused_002ddebug_002dsymbols-481"></a>Produce debugging information in stabs format (if that is supported), |
| for only symbols that are actually used. |
| |
| <br><dt><code>-femit-class-debug-always</code><dd>Instead of emitting debugging information for a C++ class in only one |
| object file, emit it in all object files using the class. This option |
| should be used only with debuggers that are unable to handle the way GCC |
| normally emits debugging information for classes because using this |
| option will increase the size of debugging information by as much as a |
| factor of two. |
| |
| <br><dt><code>-gstabs+</code><dd><a name="index-gstabs_002b-482"></a>Produce debugging information in stabs format (if that is supported), |
| using GNU extensions understood only by the GNU debugger (GDB). The |
| use of these extensions is likely to make other debuggers crash or |
| refuse to read the program. |
| |
| <br><dt><code>-gcoff</code><dd><a name="index-gcoff-483"></a>Produce debugging information in COFF format (if that is supported). |
| This is the format used by SDB on most System V systems prior to |
| System V Release 4. |
| |
| <br><dt><code>-gxcoff</code><dd><a name="index-gxcoff-484"></a>Produce debugging information in XCOFF format (if that is supported). |
| This is the format used by the DBX debugger on IBM RS/6000 systems. |
| |
| <br><dt><code>-gxcoff+</code><dd><a name="index-gxcoff_002b-485"></a>Produce debugging information in XCOFF format (if that is supported), |
| using GNU extensions understood only by the GNU debugger (GDB). The |
| use of these extensions is likely to make other debuggers crash or |
| refuse to read the program, and may cause assemblers other than the GNU |
| assembler (GAS) to fail with an error. |
| |
| <br><dt><code>-gdwarf-</code><var>version</var><dd><a name="index-gdwarf_002d_0040var_007bversion_007d-486"></a>Produce debugging information in DWARF format (if that is |
| supported). This is the format used by DBX on IRIX 6. The value |
| of <var>version</var> may be either 2, 3 or 4; the default version is 2. |
| |
| <p>Note that with DWARF version 2 some ports require, and will always |
| use, some non-conflicting DWARF 3 extensions in the unwind tables. |
| |
| <p>Version 4 may require GDB 7.0 and <samp><span class="option">-fvar-tracking-assignments</span></samp> |
| for maximum benefit. |
| |
| <br><dt><code>-gstrict-dwarf</code><dd><a name="index-gstrict_002ddwarf-487"></a>Disallow using extensions of later DWARF standard version than selected |
| with <samp><span class="option">-gdwarf-</span><var>version</var></samp>. On most targets using non-conflicting |
| DWARF extensions from later standard versions is allowed. |
| |
| <br><dt><code>-gno-strict-dwarf</code><dd><a name="index-gno_002dstrict_002ddwarf-488"></a>Allow using extensions of later DWARF standard version than selected with |
| <samp><span class="option">-gdwarf-</span><var>version</var></samp>. |
| |
| <br><dt><code>-gvms</code><dd><a name="index-gvms-489"></a>Produce debugging information in VMS debug format (if that is |
| supported). This is the format used by DEBUG on VMS systems. |
| |
| <br><dt><code>-g</code><var>level</var><dt><code>-ggdb</code><var>level</var><dt><code>-gstabs</code><var>level</var><dt><code>-gcoff</code><var>level</var><dt><code>-gxcoff</code><var>level</var><dt><code>-gvms</code><var>level</var><dd>Request debugging information and also use <var>level</var> to specify how |
| much information. The default level is 2. |
| |
| <p>Level 0 produces no debug information at all. Thus, <samp><span class="option">-g0</span></samp> negates |
| <samp><span class="option">-g</span></samp>. |
| |
| <p>Level 1 produces minimal information, enough for making backtraces in |
| parts of the program that you don't plan to debug. This includes |
| descriptions of functions and external variables, but no information |
| about local variables and no line numbers. |
| |
| <p>Level 3 includes extra information, such as all the macro definitions |
| present in the program. Some debuggers support macro expansion when |
| you use <samp><span class="option">-g3</span></samp>. |
| |
| <p><samp><span class="option">-gdwarf-2</span></samp> does not accept a concatenated debug level, because |
| GCC used to support an option <samp><span class="option">-gdwarf</span></samp> that meant to generate |
| debug information in version 1 of the DWARF format (which is very |
| different from version 2), and it would have been too confusing. That |
| debug format is long obsolete, but the option cannot be changed now. |
| Instead use an additional <samp><span class="option">-g</span><var>level</var></samp> option to change the |
| debug level for DWARF. |
| |
| <br><dt><code>-gtoggle</code><dd><a name="index-gtoggle-490"></a>Turn off generation of debug info, if leaving out this option would have |
| generated 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 |
| <samp><span class="option">-fcompare-debug</span></samp>. |
| |
| <br><dt><code>-fdump-final-insns</code><span class="roman">[</span><code>=</code><var>file</var><span class="roman">]</span><dd><a name="index-fdump_002dfinal_002dinsns-491"></a>Dump the final internal representation (RTL) to <var>file</var>. If the |
| optional argument is omitted (or if <var>file</var> is <code>.</code>), the name |
| of the dump file will be determined by appending <code>.gkd</code> to the |
| compilation output file name. |
| |
| <br><dt><code>-fcompare-debug</code><span class="roman">[</span><code>=</code><var>opts</var><span class="roman">]</span><dd><a name="index-fcompare_002ddebug-492"></a><a name="index-fno_002dcompare_002ddebug-493"></a>If no error occurs during compilation, run the compiler a second time, |
| adding <var>opts</var> and <samp><span class="option">-fcompare-debug-second</span></samp> to the arguments |
| passed to the second compilation. Dump the final internal |
| representation in both compilations, and print an error if they differ. |
| |
| <p>If the equal sign is omitted, the default <samp><span class="option">-gtoggle</span></samp> is used. |
| |
| <p>The environment variable <samp><span class="env">GCC_COMPARE_DEBUG</span></samp>, if defined, non-empty |
| and nonzero, implicitly enables <samp><span class="option">-fcompare-debug</span></samp>. If |
| <samp><span class="env">GCC_COMPARE_DEBUG</span></samp> is defined to a string starting with a dash, |
| then it is used for <var>opts</var>, otherwise the default <samp><span class="option">-gtoggle</span></samp> |
| is used. |
| |
| <p><samp><span class="option">-fcompare-debug=</span></samp>, with the equal sign but without <var>opts</var>, |
| is equivalent to <samp><span class="option">-fno-compare-debug</span></samp>, which disables the dumping |
| of the final representation and the second compilation, preventing even |
| <samp><span class="env">GCC_COMPARE_DEBUG</span></samp> from taking effect. |
| |
| <p>To verify full coverage during <samp><span class="option">-fcompare-debug</span></samp> testing, set |
| <samp><span class="env">GCC_COMPARE_DEBUG</span></samp> to say ‘<samp><span class="samp">-fcompare-debug-not-overridden</span></samp>’, |
| which GCC will reject as an invalid option in any actual compilation |
| (rather than preprocessing, assembly or linking). To get just a |
| warning, setting <samp><span class="env">GCC_COMPARE_DEBUG</span></samp> to ‘<samp><span class="samp">-w%n-fcompare-debug |
| not overridden</span></samp>’ will do. |
| |
| <br><dt><code>-fcompare-debug-second</code><dd><a name="index-fcompare_002ddebug_002dsecond-494"></a>This option is implicitly passed to the compiler for the second |
| compilation requested by <samp><span class="option">-fcompare-debug</span></samp>, along with options to |
| silence warnings, and omitting other options that would cause |
| side-effect compiler outputs to files or to the standard output. Dump |
| files and preserved temporary files are renamed so as to contain the |
| <code>.gk</code> additional extension during the second compilation, to avoid |
| overwriting those generated by the first. |
| |
| <p>When this option is passed to the compiler driver, it causes the |
| <em>first</em> compilation to be skipped, which makes it useful for little |
| other than debugging the compiler proper. |
| |
| <br><dt><code>-feliminate-dwarf2-dups</code><dd><a name="index-feliminate_002ddwarf2_002ddups-495"></a>Compress DWARF2 debugging information by eliminating duplicated |
| information about each symbol. This option only makes sense when |
| generating DWARF2 debugging information with <samp><span class="option">-gdwarf-2</span></samp>. |
| |
| <br><dt><code>-femit-struct-debug-baseonly</code><dd>Emit debug information for struct-like types |
| only when the base name of the compilation source file |
| matches the base name of file in which the struct was defined. |
| |
| <p>This option substantially reduces the size of debugging information, |
| but at significant potential loss in type information to the debugger. |
| See <samp><span class="option">-femit-struct-debug-reduced</span></samp> for a less aggressive option. |
| See <samp><span class="option">-femit-struct-debug-detailed</span></samp> for more detailed control. |
| |
| <p>This option works only with DWARF 2. |
| |
| <br><dt><code>-femit-struct-debug-reduced</code><dd>Emit debug information for struct-like types |
| only when the base name of the compilation source file |
| matches the base name of file in which the type was defined, |
| unless the struct is a template or defined in a system header. |
| |
| <p>This option significantly reduces the size of debugging information, |
| with some potential loss in type information to the debugger. |
| See <samp><span class="option">-femit-struct-debug-baseonly</span></samp> for a more aggressive option. |
| See <samp><span class="option">-femit-struct-debug-detailed</span></samp> for more detailed control. |
| |
| <p>This option works only with DWARF 2. |
| |
| <br><dt><code>-femit-struct-debug-detailed</code><span class="roman">[</span><code>=</code><var>spec-list</var><span class="roman">]</span><dd>Specify the struct-like types |
| for which the compiler will generate debug information. |
| The intent is to reduce duplicate struct debug information |
| between different object files within the same program. |
| |
| <p>This option is a detailed version of |
| <samp><span class="option">-femit-struct-debug-reduced</span></samp> and <samp><span class="option">-femit-struct-debug-baseonly</span></samp>, |
| which will serve for most needs. |
| |
| <p>A specification has the syntax |
| [‘<samp><span class="samp">dir:</span></samp>’|‘<samp><span class="samp">ind:</span></samp>’][‘<samp><span class="samp">ord:</span></samp>’|‘<samp><span class="samp">gen:</span></samp>’](‘<samp><span class="samp">any</span></samp>’|‘<samp><span class="samp">sys</span></samp>’|‘<samp><span class="samp">base</span></samp>’|‘<samp><span class="samp">none</span></samp>’) |
| |
| <p>The optional first word limits the specification to |
| structs that are used directly (‘<samp><span class="samp">dir:</span></samp>’) or used indirectly (‘<samp><span class="samp">ind:</span></samp>’). |
| A struct type is used directly when it is the type of a variable, member. |
| Indirect uses arise through pointers to structs. |
| That is, when use of an incomplete struct would be legal, the use is indirect. |
| An example is |
| ‘<samp><span class="samp">struct one direct; struct two * indirect;</span></samp>’. |
| |
| <p>The optional second word limits the specification to |
| ordinary structs (‘<samp><span class="samp">ord:</span></samp>’) or generic structs (‘<samp><span class="samp">gen:</span></samp>’). |
| Generic structs are a bit complicated to explain. |
| For C++, these are non-explicit specializations of template classes, |
| or non-template classes within the above. |
| Other programming languages have generics, |
| but ‘<samp><span class="samp">-femit-struct-debug-detailed</span></samp>’ does not yet implement them. |
| |
| <p>The third word specifies the source files for those |
| structs for which the compiler will emit debug information. |
| The values ‘<samp><span class="samp">none</span></samp>’ and ‘<samp><span class="samp">any</span></samp>’ have the normal meaning. |
| The value ‘<samp><span class="samp">base</span></samp>’ means that |
| the base of name of the file in which the type declaration appears |
| must match the base of the name of the main compilation file. |
| In practice, this means that |
| types declared in <samp><span class="file">foo.c</span></samp> and <samp><span class="file">foo.h</span></samp> will have debug information, |
| but types declared in other header will not. |
| The value ‘<samp><span class="samp">sys</span></samp>’ means those types satisfying ‘<samp><span class="samp">base</span></samp>’ |
| or declared in system or compiler headers. |
| |
| <p>You may need to experiment to determine the best settings for your application. |
| |
| <p>The default is ‘<samp><span class="samp">-femit-struct-debug-detailed=all</span></samp>’. |
| |
| <p>This option works only with DWARF 2. |
| |
| <br><dt><code>-fenable-icf-debug</code><dd><a name="index-fenable_002dicf_002ddebug-496"></a>Generate additional debug information to support identical code folding (ICF). |
| This option only works with DWARF version 2 or higher. |
| |
| <br><dt><code>-fno-merge-debug-strings</code><dd><a name="index-fmerge_002ddebug_002dstrings-497"></a><a name="index-fno_002dmerge_002ddebug_002dstrings-498"></a>Direct the linker to not merge together strings in the debugging |
| information which are identical in different object files. Merging is |
| not supported by all assemblers or linkers. Merging decreases the size |
| of the debug information in the output file at the cost of increasing |
| link processing time. Merging is enabled by default. |
| |
| <br><dt><code>-fdebug-prefix-map=</code><var>old</var><code>=</code><var>new</var><dd><a name="index-fdebug_002dprefix_002dmap-499"></a>When compiling files in directory <samp><var>old</var></samp>, record debugging |
| information describing them as in <samp><var>new</var></samp> instead. |
| |
| <br><dt><code>-fno-dwarf2-cfi-asm</code><dd><a name="index-fdwarf2_002dcfi_002dasm-500"></a><a name="index-fno_002ddwarf2_002dcfi_002dasm-501"></a>Emit DWARF 2 unwind info as compiler generated <code>.eh_frame</code> section |
| instead of using GAS <code>.cfi_*</code> directives. |
| |
| <p><a name="index-g_t_0040command_007bprof_007d-502"></a><br><dt><code>-p</code><dd><a name="index-p-503"></a>Generate extra code to write profile information suitable for the |
| analysis program <samp><span class="command">prof</span></samp>. You must use this option when compiling |
| the source files you want data about, and you must also use it when |
| linking. |
| |
| <p><a name="index-g_t_0040command_007bgprof_007d-504"></a><br><dt><code>-pg</code><dd><a name="index-pg-505"></a>Generate extra code to write profile information suitable for the |
| analysis program <samp><span class="command">gprof</span></samp>. You must use this option when compiling |
| the source files you want data about, and you must also use it when |
| linking. |
| |
| <br><dt><code>-Q</code><dd><a name="index-Q-506"></a>Makes the compiler print out each function name as it is compiled, and |
| print some statistics about each pass when it finishes. |
| |
| <br><dt><code>-ftime-report</code><dd><a name="index-ftime_002dreport-507"></a>Makes the compiler print some statistics about the time consumed by each |
| pass when it finishes. |
| |
| <br><dt><code>-fmem-report</code><dd><a name="index-fmem_002dreport-508"></a>Makes the compiler print some statistics about permanent memory |
| allocation when it finishes. |
| |
| <br><dt><code>-fpre-ipa-mem-report</code><dd><a name="index-fpre_002dipa_002dmem_002dreport-509"></a><br><dt><code>-fpost-ipa-mem-report</code><dd><a name="index-fpost_002dipa_002dmem_002dreport-510"></a>Makes the compiler print some statistics about permanent memory |
| allocation before or after interprocedural optimization. |
| |
| <br><dt><code>-fprofile-arcs</code><dd><a name="index-fprofile_002darcs-511"></a>Add code so that program flow <dfn>arcs</dfn> are instrumented. During |
| execution the program records how many times each branch and call is |
| executed and how many times it is taken or returns. When the compiled |
| program exits it saves this data to a file called |
| <samp><var>auxname</var><span class="file">.gcda</span></samp> for each source file. The data may be used for |
| profile-directed optimizations (<samp><span class="option">-fbranch-probabilities</span></samp>), or for |
| test coverage analysis (<samp><span class="option">-ftest-coverage</span></samp>). Each object file's |
| <var>auxname</var> is generated from the name of the output file, if |
| explicitly specified and it is not the final executable, otherwise it is |
| the basename of the source file. In both cases any suffix is removed |
| (e.g. <samp><span class="file">foo.gcda</span></samp> for input file <samp><span class="file">dir/foo.c</span></samp>, or |
| <samp><span class="file">dir/foo.gcda</span></samp> for output file specified as <samp><span class="option">-o dir/foo.o</span></samp>). |
| See <a href="Cross_002dprofiling.html#Cross_002dprofiling">Cross-profiling</a>. |
| |
| <p><a name="index-g_t_0040command_007bgcov_007d-512"></a><br><dt><code>--coverage</code><dd><a name="index-coverage-513"></a> |
| This option is used to compile and link code instrumented for coverage |
| analysis. The option is a synonym for <samp><span class="option">-fprofile-arcs</span></samp> |
| <samp><span class="option">-ftest-coverage</span></samp> (when compiling) and <samp><span class="option">-lgcov</span></samp> (when |
| linking). See the documentation for those options for more details. |
| |
| <ul> |
| <li>Compile the source files with <samp><span class="option">-fprofile-arcs</span></samp> plus optimization |
| and code generation options. For test coverage analysis, use the |
| additional <samp><span class="option">-ftest-coverage</span></samp> option. You do not need to profile |
| every source file in a program. |
| |
| <li>Link your object files with <samp><span class="option">-lgcov</span></samp> or <samp><span class="option">-fprofile-arcs</span></samp> |
| (the latter implies the former). |
| |
| <li>Run the program on a representative workload to generate the arc profile |
| information. This may be repeated any number of times. You can run |
| concurrent instances of your program, and provided that the file system |
| supports locking, the data files will be correctly updated. Also |
| <code>fork</code> calls are detected and correctly handled (double counting |
| will not happen). |
| |
| <li>For profile-directed optimizations, compile the source files again with |
| the same optimization and code generation options plus |
| <samp><span class="option">-fbranch-probabilities</span></samp> (see <a href="Optimize-Options.html#Optimize-Options">Options that Control Optimization</a>). |
| |
| <li>For test coverage analysis, use <samp><span class="command">gcov</span></samp> to produce human readable |
| information from the <samp><span class="file">.gcno</span></samp> and <samp><span class="file">.gcda</span></samp> files. Refer to the |
| <samp><span class="command">gcov</span></samp> documentation for further information. |
| |
| </ul> |
| |
| <p>With <samp><span class="option">-fprofile-arcs</span></samp>, for each function of your program GCC |
| creates a program flow graph, then finds a spanning tree for the graph. |
| Only arcs that are not on the spanning tree have to be instrumented: the |
| compiler adds code to count the number of times that these arcs are |
| executed. When an arc is the only exit or only entrance to a block, the |
| instrumentation code can be added to the block; otherwise, a new basic |
| block must be created to hold the instrumentation code. |
| |
| <br><dt><code>-ftest-coverage</code><dd><a name="index-ftest_002dcoverage-514"></a>Produce a notes file that the <samp><span class="command">gcov</span></samp> code-coverage utility |
| (see <a href="Gcov.html#Gcov"><samp><span class="command">gcov</span></samp>—a Test Coverage Program</a>) can use to |
| show program coverage. Each source file's note file is called |
| <samp><var>auxname</var><span class="file">.gcno</span></samp>. Refer to the <samp><span class="option">-fprofile-arcs</span></samp> option |
| above for a description of <var>auxname</var> and instructions on how to |
| generate test coverage data. Coverage data will match the source files |
| more closely, if you do not optimize. |
| |
| <br><dt><code>-fdbg-cnt-list</code><dd><a name="index-fdbg_002dcnt_002dlist-515"></a>Print the name and the counter upperbound for all debug counters. |
| |
| <br><dt><code>-fdbg-cnt=</code><var>counter-value-list</var><dd><a name="index-fdbg_002dcnt-516"></a>Set the internal debug counter upperbound. <var>counter-value-list</var> |
| is a comma-separated list of <var>name</var>:<var>value</var> pairs |
| which sets the upperbound of each debug counter <var>name</var> to <var>value</var>. |
| All debug counters have the initial upperbound of <var>UINT_MAX</var>, |
| thus dbg_cnt() returns true always unless the upperbound is set by this option. |
| e.g. With -fdbg-cnt=dce:10,tail_call:0 |
| dbg_cnt(dce) will return true only for first 10 invocations |
| and dbg_cnt(tail_call) will return false always. |
| |
| <br><dt><code>-d</code><var>letters</var><dt><code>-fdump-rtl-</code><var>pass</var><dd><a name="index-d-517"></a>Says to make debugging dumps during compilation at times specified by |
| <var>letters</var>. This is used for debugging the RTL-based passes of the |
| compiler. The file names for most of the dumps are made by appending |
| a pass number and a word to the <var>dumpname</var>, and the files are |
| created in the directory of the output file. <var>dumpname</var> 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. These switches may have different effects when |
| <samp><span class="option">-E</span></samp> is used for preprocessing. |
| |
| <p>Debug dumps can be enabled with a <samp><span class="option">-fdump-rtl</span></samp> switch or some |
| <samp><span class="option">-d</span></samp> option <var>letters</var>. Here are the possible |
| letters for use in <var>pass</var> and <var>letters</var>, and their meanings: |
| |
| <dl> |
| <dt><code>-fdump-rtl-alignments</code><dd><a name="index-fdump_002drtl_002dalignments-518"></a>Dump after branch alignments have been computed. |
| |
| <br><dt><code>-fdump-rtl-asmcons</code><dd><a name="index-fdump_002drtl_002dasmcons-519"></a>Dump after fixing rtl statements that have unsatisfied in/out constraints. |
| |
| <br><dt><code>-fdump-rtl-auto_inc_dec</code><dd><a name="index-fdump_002drtl_002dauto_005finc_005fdec-520"></a>Dump after auto-inc-dec discovery. This pass is only run on |
| architectures that have auto inc or auto dec instructions. |
| |
| <br><dt><code>-fdump-rtl-barriers</code><dd><a name="index-fdump_002drtl_002dbarriers-521"></a>Dump after cleaning up the barrier instructions. |
| |
| <br><dt><code>-fdump-rtl-bbpart</code><dd><a name="index-fdump_002drtl_002dbbpart-522"></a>Dump after partitioning hot and cold basic blocks. |
| |
| <br><dt><code>-fdump-rtl-bbro</code><dd><a name="index-fdump_002drtl_002dbbro-523"></a>Dump after block reordering. |
| |
| <br><dt><code>-fdump-rtl-btl1</code><dt><code>-fdump-rtl-btl2</code><dd><a name="index-fdump_002drtl_002dbtl2-524"></a><a name="index-fdump_002drtl_002dbtl2-525"></a><samp><span class="option">-fdump-rtl-btl1</span></samp> and <samp><span class="option">-fdump-rtl-btl2</span></samp> enable dumping |
| after the two branch |
| target load optimization passes. |
| |
| <br><dt><code>-fdump-rtl-bypass</code><dd><a name="index-fdump_002drtl_002dbypass-526"></a>Dump after jump bypassing and control flow optimizations. |
| |
| <br><dt><code>-fdump-rtl-combine</code><dd><a name="index-fdump_002drtl_002dcombine-527"></a>Dump after the RTL instruction combination pass. |
| |
| <br><dt><code>-fdump-rtl-compgotos</code><dd><a name="index-fdump_002drtl_002dcompgotos-528"></a>Dump after duplicating the computed gotos. |
| |
| <br><dt><code>-fdump-rtl-ce1</code><dt><code>-fdump-rtl-ce2</code><dt><code>-fdump-rtl-ce3</code><dd><a name="index-fdump_002drtl_002dce1-529"></a><a name="index-fdump_002drtl_002dce2-530"></a><a name="index-fdump_002drtl_002dce3-531"></a><samp><span class="option">-fdump-rtl-ce1</span></samp>, <samp><span class="option">-fdump-rtl-ce2</span></samp>, and |
| <samp><span class="option">-fdump-rtl-ce3</span></samp> enable dumping after the three |
| if conversion passes. |
| |
| <dt><code>-fdump-rtl-cprop_hardreg</code><dd><a name="index-fdump_002drtl_002dcprop_005fhardreg-532"></a>Dump after hard register copy propagation. |
| |
| <dt><code>-fdump-rtl-csa</code><dd><a name="index-fdump_002drtl_002dcsa-533"></a>Dump after combining stack adjustments. |
| |
| <br><dt><code>-fdump-rtl-cse1</code><dt><code>-fdump-rtl-cse2</code><dd><a name="index-fdump_002drtl_002dcse1-534"></a><a name="index-fdump_002drtl_002dcse2-535"></a><samp><span class="option">-fdump-rtl-cse1</span></samp> and <samp><span class="option">-fdump-rtl-cse2</span></samp> enable dumping after |
| the two common sub-expression elimination passes. |
| |
| <dt><code>-fdump-rtl-dce</code><dd><a name="index-fdump_002drtl_002ddce-536"></a>Dump after the standalone dead code elimination passes. |
| |
| <dt><code>-fdump-rtl-dbr</code><dd><a name="index-fdump_002drtl_002ddbr-537"></a>Dump after delayed branch scheduling. |
| |
| <br><dt><code>-fdump-rtl-dce1</code><dt><code>-fdump-rtl-dce2</code><dd><a name="index-fdump_002drtl_002ddce1-538"></a><a name="index-fdump_002drtl_002ddce2-539"></a><samp><span class="option">-fdump-rtl-dce1</span></samp> and <samp><span class="option">-fdump-rtl-dce2</span></samp> enable dumping after |
| the two dead store elimination passes. |
| |
| <br><dt><code>-fdump-rtl-eh</code><dd><a name="index-fdump_002drtl_002deh-540"></a>Dump after finalization of EH handling code. |
| |
| <br><dt><code>-fdump-rtl-eh_ranges</code><dd><a name="index-fdump_002drtl_002deh_005franges-541"></a>Dump after conversion of EH handling range regions. |
| |
| <br><dt><code>-fdump-rtl-expand</code><dd><a name="index-fdump_002drtl_002dexpand-542"></a>Dump after RTL generation. |
| |
| <br><dt><code>-fdump-rtl-fwprop1</code><dt><code>-fdump-rtl-fwprop2</code><dd><a name="index-fdump_002drtl_002dfwprop1-543"></a><a name="index-fdump_002drtl_002dfwprop2-544"></a><samp><span class="option">-fdump-rtl-fwprop1</span></samp> and <samp><span class="option">-fdump-rtl-fwprop2</span></samp> enable |
| dumping after the two forward propagation passes. |
| |
| <br><dt><code>-fdump-rtl-gcse1</code><dt><code>-fdump-rtl-gcse2</code><dd><a name="index-fdump_002drtl_002dgcse1-545"></a><a name="index-fdump_002drtl_002dgcse2-546"></a><samp><span class="option">-fdump-rtl-gcse1</span></samp> and <samp><span class="option">-fdump-rtl-gcse2</span></samp> enable dumping |
| after global common subexpression elimination. |
| |
| <br><dt><code>-fdump-rtl-init-regs</code><dd><a name="index-fdump_002drtl_002dinit_002dregs-547"></a>Dump after the initialization of the registers. |
| |
| <br><dt><code>-fdump-rtl-initvals</code><dd><a name="index-fdump_002drtl_002dinitvals-548"></a>Dump after the computation of the initial value sets. |
| |
| <dt><code>-fdump-rtl-into_cfglayout</code><dd><a name="index-fdump_002drtl_002dinto_005fcfglayout-549"></a>Dump after converting to cfglayout mode. |
| |
| <br><dt><code>-fdump-rtl-ira</code><dd><a name="index-fdump_002drtl_002dira-550"></a>Dump after iterated register allocation. |
| |
| <br><dt><code>-fdump-rtl-jump</code><dd><a name="index-fdump_002drtl_002djump-551"></a>Dump after the second jump optimization. |
| |
| <br><dt><code>-fdump-rtl-loop2</code><dd><a name="index-fdump_002drtl_002dloop2-552"></a><samp><span class="option">-fdump-rtl-loop2</span></samp> enables dumping after the rtl |
| loop optimization passes. |
| |
| <br><dt><code>-fdump-rtl-mach</code><dd><a name="index-fdump_002drtl_002dmach-553"></a>Dump after performing the machine dependent reorganization pass, if that |
| pass exists. |
| |
| <br><dt><code>-fdump-rtl-mode_sw</code><dd><a name="index-fdump_002drtl_002dmode_005fsw-554"></a>Dump after removing redundant mode switches. |
| |
| <br><dt><code>-fdump-rtl-rnreg</code><dd><a name="index-fdump_002drtl_002drnreg-555"></a>Dump after register renumbering. |
| |
| <dt><code>-fdump-rtl-outof_cfglayout</code><dd><a name="index-fdump_002drtl_002doutof_005fcfglayout-556"></a>Dump after converting from cfglayout mode. |
| |
| <br><dt><code>-fdump-rtl-peephole2</code><dd><a name="index-fdump_002drtl_002dpeephole2-557"></a>Dump after the peephole pass. |
| |
| <br><dt><code>-fdump-rtl-postreload</code><dd><a name="index-fdump_002drtl_002dpostreload-558"></a>Dump after post-reload optimizations. |
| |
| <dt><code>-fdump-rtl-pro_and_epilogue</code><dd><a name="index-fdump_002drtl_002dpro_005fand_005fepilogue-559"></a>Dump after generating the function pro and epilogues. |
| |
| <br><dt><code>-fdump-rtl-regmove</code><dd><a name="index-fdump_002drtl_002dregmove-560"></a>Dump after the register move pass. |
| |
| <br><dt><code>-fdump-rtl-sched1</code><dt><code>-fdump-rtl-sched2</code><dd><a name="index-fdump_002drtl_002dsched1-561"></a><a name="index-fdump_002drtl_002dsched2-562"></a><samp><span class="option">-fdump-rtl-sched1</span></samp> and <samp><span class="option">-fdump-rtl-sched2</span></samp> enable dumping |
| after the basic block scheduling passes. |
| |
| <br><dt><code>-fdump-rtl-see</code><dd><a name="index-fdump_002drtl_002dsee-563"></a>Dump after sign extension elimination. |
| |
| <br><dt><code>-fdump-rtl-seqabstr</code><dd><a name="index-fdump_002drtl_002dseqabstr-564"></a>Dump after common sequence discovery. |
| |
| <br><dt><code>-fdump-rtl-shorten</code><dd><a name="index-fdump_002drtl_002dshorten-565"></a>Dump after shortening branches. |
| |
| <br><dt><code>-fdump-rtl-sibling</code><dd><a name="index-fdump_002drtl_002dsibling-566"></a>Dump after sibling call optimizations. |
| |
| <br><dt><code>-fdump-rtl-split1</code><dt><code>-fdump-rtl-split2</code><dt><code>-fdump-rtl-split3</code><dt><code>-fdump-rtl-split4</code><dt><code>-fdump-rtl-split5</code><dd><a name="index-fdump_002drtl_002dsplit1-567"></a><a name="index-fdump_002drtl_002dsplit2-568"></a><a name="index-fdump_002drtl_002dsplit3-569"></a><a name="index-fdump_002drtl_002dsplit4-570"></a><a name="index-fdump_002drtl_002dsplit5-571"></a><samp><span class="option">-fdump-rtl-split1</span></samp>, <samp><span class="option">-fdump-rtl-split2</span></samp>, |
| <samp><span class="option">-fdump-rtl-split3</span></samp>, <samp><span class="option">-fdump-rtl-split4</span></samp> and |
| <samp><span class="option">-fdump-rtl-split5</span></samp> enable dumping after five rounds of |
| instruction splitting. |
| |
| <br><dt><code>-fdump-rtl-sms</code><dd><a name="index-fdump_002drtl_002dsms-572"></a>Dump after modulo scheduling. This pass is only run on some |
| architectures. |
| |
| <br><dt><code>-fdump-rtl-stack</code><dd><a name="index-fdump_002drtl_002dstack-573"></a>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. |
| |
| <br><dt><code>-fdump-rtl-subreg1</code><dt><code>-fdump-rtl-subreg2</code><dd><a name="index-fdump_002drtl_002dsubreg1-574"></a><a name="index-fdump_002drtl_002dsubreg2-575"></a><samp><span class="option">-fdump-rtl-subreg1</span></samp> and <samp><span class="option">-fdump-rtl-subreg2</span></samp> enable dumping after |
| the two subreg expansion passes. |
| |
| <br><dt><code>-fdump-rtl-unshare</code><dd><a name="index-fdump_002drtl_002dunshare-576"></a>Dump after all rtl has been unshared. |
| |
| <br><dt><code>-fdump-rtl-vartrack</code><dd><a name="index-fdump_002drtl_002dvartrack-577"></a>Dump after variable tracking. |
| |
| <br><dt><code>-fdump-rtl-vregs</code><dd><a name="index-fdump_002drtl_002dvregs-578"></a>Dump after converting virtual registers to hard registers. |
| |
| <br><dt><code>-fdump-rtl-web</code><dd><a name="index-fdump_002drtl_002dweb-579"></a>Dump after live range splitting. |
| |
| <br><dt><code>-fdump-rtl-regclass</code><dt><code>-fdump-rtl-subregs_of_mode_init</code><dt><code>-fdump-rtl-subregs_of_mode_finish</code><dt><code>-fdump-rtl-dfinit</code><dt><code>-fdump-rtl-dfinish</code><dd><a name="index-fdump_002drtl_002dregclass-580"></a><a name="index-fdump_002drtl_002dsubregs_005fof_005fmode_005finit-581"></a><a name="index-fdump_002drtl_002dsubregs_005fof_005fmode_005ffinish-582"></a><a name="index-fdump_002drtl_002ddfinit-583"></a><a name="index-fdump_002drtl_002ddfinish-584"></a>These dumps are defined but always produce empty files. |
| |
| <br><dt><code>-fdump-rtl-all</code><dd><a name="index-fdump_002drtl_002dall-585"></a>Produce all the dumps listed above. |
| |
| <br><dt><code>-dA</code><dd><a name="index-dA-586"></a>Annotate the assembler output with miscellaneous debugging information. |
| |
| <br><dt><code>-dD</code><dd><a name="index-dD-587"></a>Dump all macro definitions, at the end of preprocessing, in addition to |
| normal output. |
| |
| <br><dt><code>-dH</code><dd><a name="index-dH-588"></a>Produce a core dump whenever an error occurs. |
| |
| <br><dt><code>-dm</code><dd><a name="index-dm-589"></a>Print statistics on memory usage, at the end of the run, to |
| standard error. |
| |
| <br><dt><code>-dp</code><dd><a name="index-dp-590"></a>Annotate the assembler output with a comment indicating which |
| pattern and alternative was used. The length of each instruction is |
| also printed. |
| |
| <br><dt><code>-dP</code><dd><a name="index-dP-591"></a>Dump the RTL in the assembler output as a comment before each instruction. |
| Also turns on <samp><span class="option">-dp</span></samp> annotation. |
| |
| <br><dt><code>-dv</code><dd><a name="index-dv-592"></a>For each of the other indicated dump files (<samp><span class="option">-fdump-rtl-</span><var>pass</var></samp>), |
| dump a representation of the control flow graph suitable for viewing with VCG |
| to <samp><var>file</var><span class="file">.</span><var>pass</var><span class="file">.vcg</span></samp>. |
| |
| <br><dt><code>-dx</code><dd><a name="index-dx-593"></a>Just generate RTL for a function instead of compiling it. Usually used |
| with <samp><span class="option">-fdump-rtl-expand</span></samp>. |
| |
| <br><dt><code>-dy</code><dd><a name="index-dy-594"></a>Dump debugging information during parsing, to standard error. |
| </dl> |
| |
| <br><dt><code>-fdump-noaddr</code><dd><a name="index-fdump_002dnoaddr-595"></a>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. |
| |
| <br><dt><code>-fdump-unnumbered</code><dd><a name="index-fdump_002dunnumbered-596"></a>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 |
| <samp><span class="option">-g</span></samp>. |
| |
| <br><dt><code>-fdump-unnumbered-links</code><dd><a name="index-fdump_002dunnumbered_002dlinks-597"></a>When doing debugging dumps (see <samp><span class="option">-d</span></samp> option above), suppress |
| instruction numbers for the links to the previous and next instructions |
| in a sequence. |
| |
| <br><dt><code>-fdump-translation-unit </code><span class="roman">(C++ only)</span><dt><code>-fdump-translation-unit-</code><var>options</var> <span class="roman">(C++ only)</span><dd><a name="index-fdump_002dtranslation_002dunit-598"></a>Dump a representation of the tree structure for the entire translation |
| unit to a file. The file name is made by appending <samp><span class="file">.tu</span></samp> to the |
| source file name, and the file is created in the same directory as the |
| output file. If the ‘<samp><span class="samp">-</span><var>options</var></samp>’ form is used, <var>options</var> |
| controls the details of the dump as described for the |
| <samp><span class="option">-fdump-tree</span></samp> options. |
| |
| <br><dt><code>-fdump-class-hierarchy </code><span class="roman">(C++ only)</span><dt><code>-fdump-class-hierarchy-</code><var>options</var> <span class="roman">(C++ only)</span><dd><a name="index-fdump_002dclass_002dhierarchy-599"></a>Dump a representation of each class's hierarchy and virtual function |
| table layout to a file. The file name is made by appending |
| <samp><span class="file">.class</span></samp> to the source file name, and the file is created in the |
| same directory as the output file. If the ‘<samp><span class="samp">-</span><var>options</var></samp>’ form |
| is used, <var>options</var> controls the details of the dump as described |
| for the <samp><span class="option">-fdump-tree</span></samp> options. |
| |
| <br><dt><code>-fdump-ipa-</code><var>switch</var><dd><a name="index-fdump_002dipa-600"></a>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: |
| |
| <dl> |
| <dt>‘<samp><span class="samp">all</span></samp>’<dd>Enables all inter-procedural analysis dumps. |
| |
| <br><dt>‘<samp><span class="samp">cgraph</span></samp>’<dd>Dumps information about call-graph optimization, unused function removal, |
| and inlining decisions. |
| |
| <br><dt>‘<samp><span class="samp">inline</span></samp>’<dd>Dump after function inlining. |
| |
| </dl> |
| |
| <br><dt><code>-fdump-statistics-</code><var>option</var><dd><a name="index-fdump_002dstatistics-601"></a>Enable and control dumping of pass statistics in a separate file. The |
| file name is generated by appending a suffix ending in |
| ‘<samp><span class="samp">.statistics</span></samp>’ to the source file name, and the file is created in |
| the same directory as the output file. If the ‘<samp><span class="samp">-</span><var>option</var></samp>’ |
| form is used, ‘<samp><span class="samp">-stats</span></samp>’ will cause counters to be summed over the |
| whole compilation unit while ‘<samp><span class="samp">-details</span></samp>’ will dump every event as |
| the passes generate them. The default with no option is to sum |
| counters for each function compiled. |
| |
| <br><dt><code>-fdump-tree-</code><var>switch</var><dt><code>-fdump-tree-</code><var>switch</var><code>-</code><var>options</var><dd><a name="index-fdump_002dtree-602"></a>Control the dumping at various stages of processing the intermediate |
| 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. If the |
| ‘<samp><span class="samp">-</span><var>options</var></samp>’ form is used, <var>options</var> is a list of |
| ‘<samp><span class="samp">-</span></samp>’ separated options that control the details of the dump. Not |
| all options are applicable to all dumps, those which are not |
| meaningful will be ignored. The following options are available |
| |
| <dl> |
| <dt>‘<samp><span class="samp">address</span></samp>’<dd>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. |
| <br><dt>‘<samp><span class="samp">asmname</span></samp>’<dd>If <code>DECL_ASSEMBLER_NAME</code> has been set for a given decl, use that |
| in the dump instead of <code>DECL_NAME</code>. Its primary use is ease of |
| use working backward from mangled names in the assembly file. |
| <br><dt>‘<samp><span class="samp">slim</span></samp>’<dd>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. |
| <br><dt>‘<samp><span class="samp">raw</span></samp>’<dd>Print a raw representation of the tree. By default, trees are |
| pretty-printed into a C-like representation. |
| <br><dt>‘<samp><span class="samp">details</span></samp>’<dd>Enable more detailed dumps (not honored by every dump option). |
| <br><dt>‘<samp><span class="samp">stats</span></samp>’<dd>Enable dumping various statistics about the pass (not honored by every dump |
| option). |
| <br><dt>‘<samp><span class="samp">blocks</span></samp>’<dd>Enable showing basic block boundaries (disabled in raw dumps). |
| <br><dt>‘<samp><span class="samp">vops</span></samp>’<dd>Enable showing virtual operands for every statement. |
| <br><dt>‘<samp><span class="samp">lineno</span></samp>’<dd>Enable showing line numbers for statements. |
| <br><dt>‘<samp><span class="samp">uid</span></samp>’<dd>Enable showing the unique ID (<code>DECL_UID</code>) for each variable. |
| <br><dt>‘<samp><span class="samp">verbose</span></samp>’<dd>Enable showing the tree dump for each statement. |
| <br><dt>‘<samp><span class="samp">eh</span></samp>’<dd>Enable showing the EH region number holding each statement. |
| <br><dt>‘<samp><span class="samp">all</span></samp>’<dd>Turn on all options, except <samp><span class="option">raw</span></samp>, <samp><span class="option">slim</span></samp>, <samp><span class="option">verbose</span></samp> |
| and <samp><span class="option">lineno</span></samp>. |
| </dl> |
| |
| <p>The following tree dumps are possible: |
| <dl> |
| <dt>‘<samp><span class="samp">original</span></samp>’<dd><a name="index-fdump_002dtree_002doriginal-603"></a>Dump before any tree based optimization, to <samp><var>file</var><span class="file">.original</span></samp>. |
| |
| <br><dt>‘<samp><span class="samp">optimized</span></samp>’<dd><a name="index-fdump_002dtree_002doptimized-604"></a>Dump after all tree based optimization, to <samp><var>file</var><span class="file">.optimized</span></samp>. |
| |
| <br><dt>‘<samp><span class="samp">gimple</span></samp>’<dd><a name="index-fdump_002dtree_002dgimple-605"></a>Dump each function before and after the gimplification pass to a file. The |
| file name is made by appending <samp><span class="file">.gimple</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">cfg</span></samp>’<dd><a name="index-fdump_002dtree_002dcfg-606"></a>Dump the control flow graph of each function to a file. The file name is |
| made by appending <samp><span class="file">.cfg</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">vcg</span></samp>’<dd><a name="index-fdump_002dtree_002dvcg-607"></a>Dump the control flow graph of each function to a file in VCG format. The |
| file name is made by appending <samp><span class="file">.vcg</span></samp> to the source file name. Note |
| that if the file contains more than one function, the generated file cannot |
| be used directly by VCG. You will need to cut and paste each function's |
| graph into its own separate file first. |
| |
| <br><dt>‘<samp><span class="samp">ch</span></samp>’<dd><a name="index-fdump_002dtree_002dch-608"></a>Dump each function after copying loop headers. The file name is made by |
| appending <samp><span class="file">.ch</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">ssa</span></samp>’<dd><a name="index-fdump_002dtree_002dssa-609"></a>Dump SSA related information to a file. The file name is made by appending |
| <samp><span class="file">.ssa</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">alias</span></samp>’<dd><a name="index-fdump_002dtree_002dalias-610"></a>Dump aliasing information for each function. The file name is made by |
| appending <samp><span class="file">.alias</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">ccp</span></samp>’<dd><a name="index-fdump_002dtree_002dccp-611"></a>Dump each function after CCP. The file name is made by appending |
| <samp><span class="file">.ccp</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">storeccp</span></samp>’<dd><a name="index-fdump_002dtree_002dstoreccp-612"></a>Dump each function after STORE-CCP. The file name is made by appending |
| <samp><span class="file">.storeccp</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">pre</span></samp>’<dd><a name="index-fdump_002dtree_002dpre-613"></a>Dump trees after partial redundancy elimination. The file name is made |
| by appending <samp><span class="file">.pre</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">fre</span></samp>’<dd><a name="index-fdump_002dtree_002dfre-614"></a>Dump trees after full redundancy elimination. The file name is made |
| by appending <samp><span class="file">.fre</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">copyprop</span></samp>’<dd><a name="index-fdump_002dtree_002dcopyprop-615"></a>Dump trees after copy propagation. The file name is made |
| by appending <samp><span class="file">.copyprop</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">store_copyprop</span></samp>’<dd><a name="index-fdump_002dtree_002dstore_005fcopyprop-616"></a>Dump trees after store copy-propagation. The file name is made |
| by appending <samp><span class="file">.store_copyprop</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">dce</span></samp>’<dd><a name="index-fdump_002dtree_002ddce-617"></a>Dump each function after dead code elimination. The file name is made by |
| appending <samp><span class="file">.dce</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">mudflap</span></samp>’<dd><a name="index-fdump_002dtree_002dmudflap-618"></a>Dump each function after adding mudflap instrumentation. The file name is |
| made by appending <samp><span class="file">.mudflap</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">sra</span></samp>’<dd><a name="index-fdump_002dtree_002dsra-619"></a>Dump each function after performing scalar replacement of aggregates. The |
| file name is made by appending <samp><span class="file">.sra</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">sink</span></samp>’<dd><a name="index-fdump_002dtree_002dsink-620"></a>Dump each function after performing code sinking. The file name is made |
| by appending <samp><span class="file">.sink</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">dom</span></samp>’<dd><a name="index-fdump_002dtree_002ddom-621"></a>Dump each function after applying dominator tree optimizations. The file |
| name is made by appending <samp><span class="file">.dom</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">dse</span></samp>’<dd><a name="index-fdump_002dtree_002ddse-622"></a>Dump each function after applying dead store elimination. The file |
| name is made by appending <samp><span class="file">.dse</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">phiopt</span></samp>’<dd><a name="index-fdump_002dtree_002dphiopt-623"></a>Dump each function after optimizing PHI nodes into straightline code. The file |
| name is made by appending <samp><span class="file">.phiopt</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">forwprop</span></samp>’<dd><a name="index-fdump_002dtree_002dforwprop-624"></a>Dump each function after forward propagating single use variables. The file |
| name is made by appending <samp><span class="file">.forwprop</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">copyrename</span></samp>’<dd><a name="index-fdump_002dtree_002dcopyrename-625"></a>Dump each function after applying the copy rename optimization. The file |
| name is made by appending <samp><span class="file">.copyrename</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">nrv</span></samp>’<dd><a name="index-fdump_002dtree_002dnrv-626"></a>Dump each function after applying the named return value optimization on |
| generic trees. The file name is made by appending <samp><span class="file">.nrv</span></samp> to the source |
| file name. |
| |
| <br><dt>‘<samp><span class="samp">vect</span></samp>’<dd><a name="index-fdump_002dtree_002dvect-627"></a>Dump each function after applying vectorization of loops. The file name is |
| made by appending <samp><span class="file">.vect</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">slp</span></samp>’<dd><a name="index-fdump_002dtree_002dslp-628"></a>Dump each function after applying vectorization of basic blocks. The file name |
| is made by appending <samp><span class="file">.slp</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">vrp</span></samp>’<dd><a name="index-fdump_002dtree_002dvrp-629"></a>Dump each function after Value Range Propagation (VRP). The file name |
| is made by appending <samp><span class="file">.vrp</span></samp> to the source file name. |
| |
| <br><dt>‘<samp><span class="samp">all</span></samp>’<dd><a name="index-fdump_002dtree_002dall-630"></a>Enable all the available tree dumps with the flags provided in this option. |
| </dl> |
| |
| <br><dt><code>-ftree-vectorizer-verbose=</code><var>n</var><dd><a name="index-ftree_002dvectorizer_002dverbose-631"></a>This option controls the amount of debugging output the vectorizer prints. |
| This information is written to standard error, unless |
| <samp><span class="option">-fdump-tree-all</span></samp> or <samp><span class="option">-fdump-tree-vect</span></samp> is specified, |
| in which case it is output to the usual dump listing file, <samp><span class="file">.vect</span></samp>. |
| For <var>n</var>=0 no diagnostic information is reported. |
| If <var>n</var>=1 the vectorizer reports each loop that got vectorized, |
| and the total number of loops that got vectorized. |
| If <var>n</var>=2 the vectorizer also reports non-vectorized loops that passed |
| the first analysis phase (vect_analyze_loop_form) - i.e. countable, |
| inner-most, single-bb, single-entry/exit loops. This is the same verbosity |
| level that <samp><span class="option">-fdump-tree-vect-stats</span></samp> uses. |
| Higher verbosity levels mean either more information dumped for each |
| reported loop, or same amount of information reported for more loops: |
| if <var>n</var>=3, vectorizer cost model information is reported. |
| If <var>n</var>=4, alignment related information is added to the reports. |
| If <var>n</var>=5, data-references related information (e.g. memory dependences, |
| memory access-patterns) is added to the reports. |
| If <var>n</var>=6, the vectorizer reports also non-vectorized inner-most loops |
| that did not pass the first analysis phase (i.e., may not be countable, or |
| may have complicated control-flow). |
| If <var>n</var>=7, the vectorizer reports also non-vectorized nested loops. |
| If <var>n</var>=8, SLP related information is added to the reports. |
| For <var>n</var>=9, all the information the vectorizer generates during its |
| analysis and transformation is reported. This is the same verbosity level |
| that <samp><span class="option">-fdump-tree-vect-details</span></samp> uses. |
| |
| <br><dt><code>-frandom-seed=</code><var>string</var><dd><a name="index-frandom_002dseed-632"></a>This option provides a seed that GCC uses when it would otherwise use |
| random numbers. It is used to generate 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 <samp><span class="option">-frandom-seed</span></samp> option to produce |
| reproducibly identical object files. |
| |
| <p>The <var>string</var> should be different for every file you compile. |
| |
| <br><dt><code>-fsched-verbose=</code><var>n</var><dd><a name="index-fsched_002dverbose-633"></a>On targets that use instruction scheduling, this option controls the |
| amount of debugging output the scheduler prints. This information is |
| written to standard error, unless <samp><span class="option">-fdump-rtl-sched1</span></samp> or |
| <samp><span class="option">-fdump-rtl-sched2</span></samp> is specified, in which case it is output |
| to the usual dump listing file, <samp><span class="file">.sched1</span></samp> or <samp><span class="file">.sched2</span></samp> |
| respectively. However for <var>n</var> greater than nine, the output is |
| always printed to standard error. |
| |
| <p>For <var>n</var> greater than zero, <samp><span class="option">-fsched-verbose</span></samp> outputs the |
| same information as <samp><span class="option">-fdump-rtl-sched1</span></samp> and <samp><span class="option">-fdump-rtl-sched2</span></samp>. |
| For <var>n</var> greater than one, it also output basic block probabilities, |
| detailed ready list information and unit/insn info. For <var>n</var> greater |
| than two, it includes RTL at abort point, control-flow and regions info. |
| And for <var>n</var> over four, <samp><span class="option">-fsched-verbose</span></samp> also includes |
| dependence info. |
| |
| <br><dt><code>-save-temps</code><dt><code>-save-temps=cwd</code><dd><a name="index-save_002dtemps-634"></a>Store the usual “temporary” intermediate files permanently; place them |
| in the current directory and name them based on the source file. Thus, |
| compiling <samp><span class="file">foo.c</span></samp> with ‘<samp><span class="samp">-c -save-temps</span></samp>’ would produce files |
| <samp><span class="file">foo.i</span></samp> and <samp><span class="file">foo.s</span></samp>, as well as <samp><span class="file">foo.o</span></samp>. This creates a |
| preprocessed <samp><span class="file">foo.i</span></samp> output file even though the compiler now |
| normally uses an integrated preprocessor. |
| |
| <p>When used in combination with the <samp><span class="option">-x</span></samp> command line option, |
| <samp><span class="option">-save-temps</span></samp> 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 <samp><span class="option">-save-temps</span></samp>. |
| |
| <p>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: |
| |
| <pre class="smallexample"> gcc -save-temps -o outdir1/foo.o indir1/foo.c& |
| gcc -save-temps -o outdir2/foo.o indir2/foo.c& |
| </pre> |
| <p>may result in <samp><span class="file">foo.i</span></samp> and <samp><span class="file">foo.o</span></samp> being written to |
| simultaneously by both compilers. |
| |
| <br><dt><code>-save-temps=obj</code><dd><a name="index-save_002dtemps_003dobj-635"></a>Store the usual “temporary” intermediate files permanently. If the |
| <samp><span class="option">-o</span></samp> option is used, the temporary files are based on the |
| object file. If the <samp><span class="option">-o</span></samp> option is not used, the |
| <samp><span class="option">-save-temps=obj</span></samp> switch behaves like <samp><span class="option">-save-temps</span></samp>. |
| |
| <p>For example: |
| |
| <pre class="smallexample"> 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 |
| </pre> |
| <p>would create <samp><span class="file">foo.i</span></samp>, <samp><span class="file">foo.s</span></samp>, <samp><span class="file">dir/xbar.i</span></samp>, |
| <samp><span class="file">dir/xbar.s</span></samp>, <samp><span class="file">dir2/yfoobar.i</span></samp>, <samp><span class="file">dir2/yfoobar.s</span></samp>, and |
| <samp><span class="file">dir2/yfoobar.o</span></samp>. |
| |
| <br><dt><code>-time</code><span class="roman">[</span><code>=</code><var>file</var><span class="roman">]</span><dd><a name="index-time-636"></a>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). |
| |
| <p>Without the specification of an output file, the output looks like this: |
| |
| <pre class="smallexample"> # cc1 0.12 0.01 |
| # as 0.00 0.01 |
| </pre> |
| <p>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. |
| |
| <p>With the specification of an output file, the output is appended to the |
| named file, and it looks like this: |
| |
| <pre class="smallexample"> 0.12 0.01 cc1 <var>options</var> |
| 0.00 0.01 as <var>options</var> |
| </pre> |
| <p>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. |
| |
| <br><dt><code>-fvar-tracking</code><dd><a name="index-fvar_002dtracking-637"></a>Run variable tracking pass. It computes where variables are stored at each |
| position in code. Better debugging information is then generated |
| (if the debugging information format supports this information). |
| |
| <p>It is enabled by default when compiling with optimization (<samp><span class="option">-Os</span></samp>, |
| <samp><span class="option">-O</span></samp>, <samp><span class="option">-O2</span></samp>, <small class="dots">...</small>), debugging information (<samp><span class="option">-g</span></samp>) and |
| the debug info format supports it. |
| |
| <br><dt><code>-fvar-tracking-assignments</code><dd><a name="index-fvar_002dtracking_002dassignments-638"></a><a name="index-fno_002dvar_002dtracking_002dassignments-639"></a>Annotate assignments to user variables early in the compilation and |
| attempt to carry the annotations over throughout the compilation all the |
| way to the end, in an attempt to improve debug information while |
| optimizing. Use of <samp><span class="option">-gdwarf-4</span></samp> is recommended along with it. |
| |
| <p>It can be enabled even if var-tracking is disabled, in which case |
| annotations will be created and maintained, but discarded at the end. |
| |
| <br><dt><code>-fvar-tracking-assignments-toggle</code><dd><a name="index-fvar_002dtracking_002dassignments_002dtoggle-640"></a><a name="index-fno_002dvar_002dtracking_002dassignments_002dtoggle-641"></a>Toggle <samp><span class="option">-fvar-tracking-assignments</span></samp>, in the same way that |
| <samp><span class="option">-gtoggle</span></samp> toggles <samp><span class="option">-g</span></samp>. |
| |
| <br><dt><code>-print-file-name=</code><var>library</var><dd><a name="index-print_002dfile_002dname-642"></a>Print the full absolute name of the library file <var>library</var> 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. |
| |
| <br><dt><code>-print-multi-directory</code><dd><a name="index-print_002dmulti_002ddirectory-643"></a>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 <samp><span class="env">GCC_EXEC_PREFIX</span></samp>. |
| |
| <br><dt><code>-print-multi-lib</code><dd><a name="index-print_002dmulti_002dlib-644"></a>Print the mapping from multilib directory names to compiler switches |
| that enable them. The directory name is separated from the switches by |
| ‘<samp><span class="samp">;</span></samp>’, and each switch starts with an ‘<samp><span class="samp">@</span></samp>’ instead of the |
| ‘<samp><span class="samp">-</span></samp>’, without spaces between multiple switches. This is supposed to |
| ease shell-processing. |
| |
| <br><dt><code>-print-multi-os-directory</code><dd><a name="index-print_002dmulti_002dos_002ddirectory-645"></a>Print the path to OS libraries for the selected |
| multilib, relative to some <samp><span class="file">lib</span></samp> subdirectory. If OS libraries are |
| present in the <samp><span class="file">lib</span></samp> subdirectory and no multilibs are used, this is |
| usually just <samp><span class="file">.</span></samp>, if OS libraries are present in <samp><span class="file">lib</span><var>suffix</var></samp> |
| sibling directories this prints e.g. <samp><span class="file">../lib64</span></samp>, <samp><span class="file">../lib</span></samp> or |
| <samp><span class="file">../lib32</span></samp>, or if OS libraries are present in <samp><span class="file">lib/</span><var>subdir</var></samp> |
| subdirectories it prints e.g. <samp><span class="file">amd64</span></samp>, <samp><span class="file">sparcv9</span></samp> or <samp><span class="file">ev6</span></samp>. |
| |
| <br><dt><code>-print-prog-name=</code><var>program</var><dd><a name="index-print_002dprog_002dname-646"></a>Like <samp><span class="option">-print-file-name</span></samp>, but searches for a program such as ‘<samp><span class="samp">cpp</span></samp>’. |
| |
| <br><dt><code>-print-libgcc-file-name</code><dd><a name="index-print_002dlibgcc_002dfile_002dname-647"></a>Same as <samp><span class="option">-print-file-name=libgcc.a</span></samp>. |
| |
| <p>This is useful when you use <samp><span class="option">-nostdlib</span></samp> or <samp><span class="option">-nodefaultlibs</span></samp> |
| but you do want to link with <samp><span class="file">libgcc.a</span></samp>. You can do |
| |
| <pre class="smallexample"> gcc -nostdlib <var>files</var>... `gcc -print-libgcc-file-name` |
| </pre> |
| <br><dt><code>-print-search-dirs</code><dd><a name="index-print_002dsearch_002ddirs-648"></a>Print the name of the configured installation directory and a list of |
| program and library directories <samp><span class="command">gcc</span></samp> will search—and don't do anything else. |
| |
| <p>This is useful when <samp><span class="command">gcc</span></samp> prints the error message |
| ‘<samp><span class="samp">installation problem, cannot exec cpp0: No such file or directory</span></samp>’. |
| To resolve this you either need to put <samp><span class="file">cpp0</span></samp> and the other compiler |
| components where <samp><span class="command">gcc</span></samp> expects to find them, or you can set the environment |
| variable <samp><span class="env">GCC_EXEC_PREFIX</span></samp> to the directory where you installed them. |
| Don't forget the trailing ‘<samp><span class="samp">/</span></samp>’. |
| See <a href="Environment-Variables.html#Environment-Variables">Environment Variables</a>. |
| |
| <br><dt><code>-print-sysroot</code><dd><a name="index-print_002dsysroot-649"></a>Print the target sysroot directory that will be used during |
| compilation. This is the target sysroot specified either at configure |
| time or using the <samp><span class="option">--sysroot</span></samp> option, possibly with an extra |
| suffix that depends on compilation options. If no target sysroot is |
| specified, the option prints nothing. |
| |
| <br><dt><code>-print-sysroot-headers-suffix</code><dd><a name="index-print_002dsysroot_002dheaders_002dsuffix-650"></a>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. |
| |
| <br><dt><code>-dumpmachine</code><dd><a name="index-dumpmachine-651"></a>Print the compiler's target machine (for example, |
| ‘<samp><span class="samp">i686-pc-linux-gnu</span></samp>’)—and don't do anything else. |
| |
| <br><dt><code>-dumpversion</code><dd><a name="index-dumpversion-652"></a>Print the compiler version (for example, ‘<samp><span class="samp">3.0</span></samp>’)—and don't do |
| anything else. |
| |
| <br><dt><code>-dumpspecs</code><dd><a name="index-dumpspecs-653"></a>Print the compiler's built-in specs—and don't do anything else. (This |
| is used when GCC itself is being built.) See <a href="Spec-Files.html#Spec-Files">Spec Files</a>. |
| |
| <br><dt><code>-feliminate-unused-debug-types</code><dd><a name="index-feliminate_002dunused_002ddebug_002dtypes-654"></a>Normally, when producing DWARF2 output, GCC will emit debugging |
| information for all types declared in a compilation |
| unit, regardless of whether or not they are actually used |
| in that compilation unit. Sometimes this is useful, such as |
| if, in the debugger, you want to cast a value to a type that is |
| not actually used in your program (but is declared). More often, |
| however, this results in a significant amount of wasted space. |
| With this option, GCC will avoid producing debug symbol output |
| for types that are nowhere used in the source file being compiled. |
| </dl> |
| |
| </body></html> |
| |
