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 <a name="File-Framework"></a>
 <div class="header">
 <p>
 Next: <a href="Data-Output.html#Data-Output" accesskey="n" rel="next">Data Output</a>, Up: <a href="Assembler-Format.html#Assembler-Format" accesskey="u" rel="up">Assembler Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
 </div>
 <hr>
 <a name="The-Overall-Framework-of-an-Assembler-File"></a>
 <h4 class="subsection">17.21.1 The Overall Framework of an Assembler File</h4>
 <a name="index-assembler-format"></a>
 <a name="index-output-of-assembler-code"></a>

 <p>This describes the overall framework of an assembly file.
 </p>
 <a name="index-default_005ffile_005fstart"></a>
 <dl>
 <dt><a name="index-TARGET_005fASM_005fFILE_005fSTART"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_FILE_START</strong> <em>(void)</em></dt>
 <dd><p>Output to <code>asm_out_file</code> any text which the assembler expects to
 find at the beginning of a file.  The default behavior is controlled
 by two flags, documented below.  Unless your target&rsquo;s assembler is
 quite unusual, if you override the default, you should call
 <code>default_file_start</code> at some point in your target hook.  This
 lets other target files rely on these variables.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fFILE_005fSTART_005fAPP_005fOFF"></a>Target Hook: <em>bool</em> <strong>TARGET_ASM_FILE_START_APP_OFF</strong></dt>
 <dd><p>If this flag is true, the text of the macro <code>ASM_APP_OFF</code> will be
 printed as the very first line in the assembly file, unless
 <samp>-fverbose-asm</samp> is in effect.  (If that macro has been defined
 to the empty string, this variable has no effect.)  With the normal
 definition of <code>ASM_APP_OFF</code>, the effect is to notify the GNU
 assembler that it need not bother stripping comments or extra
 whitespace from its input.  This allows it to work a bit faster.
 </p>
 <p>The default is false.  You should not set it to true unless you have
 verified that your port does not generate any extra whitespace or
 comments that will cause GAS to issue errors in NO_APP mode.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fFILE_005fSTART_005fFILE_005fDIRECTIVE"></a>Target Hook: <em>bool</em> <strong>TARGET_ASM_FILE_START_FILE_DIRECTIVE</strong></dt>
 <dd><p>If this flag is true, <code>output_file_directive</code> will be called
 for the primary source file, immediately after printing
 <code>ASM_APP_OFF</code> (if that is enabled).  Most ELF assemblers expect
 this to be done.  The default is false.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fFILE_005fEND"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_FILE_END</strong> <em>(void)</em></dt>
 <dd><p>Output to <code>asm_out_file</code> any text which the assembler expects
 to find at the end of a file.  The default is to output nothing.
 </p></dd></dl>

 <dl>
 <dt><a name="index-file_005fend_005findicate_005fexec_005fstack"></a>Function: <em>void</em> <strong>file_end_indicate_exec_stack</strong> <em>()</em></dt>
 <dd><p>Some systems use a common convention, the &lsquo;<samp>.note.GNU-stack</samp>&rsquo;
 special section, to indicate whether or not an object file relies on
 the stack being executable.  If your system uses this convention, you
 should define <code>TARGET_ASM_FILE_END</code> to this function.  If you
 need to do other things in that hook, have your hook function call
 this function.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fLTO_005fSTART"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_LTO_START</strong> <em>(void)</em></dt>
 <dd><p>Output to <code>asm_out_file</code> any text which the assembler expects
 to find at the start of an LTO section.  The default is to output
 nothing.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fLTO_005fEND"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_LTO_END</strong> <em>(void)</em></dt>
 <dd><p>Output to <code>asm_out_file</code> any text which the assembler expects
 to find at the end of an LTO section.  The default is to output
 nothing.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fCODE_005fEND"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_CODE_END</strong> <em>(void)</em></dt>
 <dd><p>Output to <code>asm_out_file</code> any text which is needed before emitting
 unwind info and debug info at the end of a file.  Some targets emit
 here PIC setup thunks that cannot be emitted at the end of file,
 because they couldn&rsquo;t have unwind info then.  The default is to output
 nothing.
 </p></dd></dl>

 <dl>
 <dt><a name="index-ASM_005fCOMMENT_005fSTART"></a>Macro: <strong>ASM_COMMENT_START</strong></dt>
 <dd><p>A C string constant describing how to begin a comment in the target
 assembler language.  The compiler assumes that the comment will end at
 the end of the line.
 </p></dd></dl>

 <dl>
 <dt><a name="index-ASM_005fAPP_005fON"></a>Macro: <strong>ASM_APP_ON</strong></dt>
 <dd><p>A C string constant for text to be output before each <code>asm</code>
 statement or group of consecutive ones.  Normally this is
 <code>&quot;#APP&quot;</code>, which is a comment that has no effect on most
 assemblers but tells the GNU assembler that it must check the lines
 that follow for all valid assembler constructs.
 </p></dd></dl>

 <dl>
 <dt><a name="index-ASM_005fAPP_005fOFF"></a>Macro: <strong>ASM_APP_OFF</strong></dt>
 <dd><p>A C string constant for text to be output after each <code>asm</code>
 statement or group of consecutive ones.  Normally this is
 <code>&quot;#NO_APP&quot;</code>, which tells the GNU assembler to resume making the
 time-saving assumptions that are valid for ordinary compiler output.
 </p></dd></dl>

 <dl>
 <dt><a name="index-ASM_005fOUTPUT_005fSOURCE_005fFILENAME"></a>Macro: <strong>ASM_OUTPUT_SOURCE_FILENAME</strong> <em>(<var>stream</var>, <var>name</var>)</em></dt>
 <dd><p>A C statement to output COFF information or DWARF debugging information
 which indicates that filename <var>name</var> is the current source file to
 the stdio stream <var>stream</var>.
 </p>
 <p>This macro need not be defined if the standard form of output
 for the file format in use is appropriate.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fOUTPUT_005fSOURCE_005fFILENAME"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_OUTPUT_SOURCE_FILENAME</strong> <em>(FILE *<var>file</var>, const char *<var>name</var>)</em></dt>
 <dd><p>Output COFF information or DWARF debugging information which indicates that filename <var>name</var> is the current source file to the stdio stream <var>file</var>.
 </p>
 <p>This target hook need not be defined if the standard form of output for the file format in use is appropriate.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fOUTPUT_005fIDENT"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_OUTPUT_IDENT</strong> <em>(const char *<var>name</var>)</em></dt>
 <dd><p>Output a string based on <var>name</var>, suitable for the &lsquo;<samp>#ident</samp>&rsquo;  directive, or the equivalent directive or pragma in non-C-family languages.  If this hook is not defined, nothing is output for the &lsquo;<samp>#ident</samp>&rsquo;  directive.
 </p></dd></dl>

 <dl>
 <dt><a name="index-OUTPUT_005fQUOTED_005fSTRING"></a>Macro: <strong>OUTPUT_QUOTED_STRING</strong> <em>(<var>stream</var>, <var>string</var>)</em></dt>
 <dd><p>A C statement to output the string <var>string</var> to the stdio stream
 <var>stream</var>.  If you do not call the function <code>output_quoted_string</code>
 in your config files, GCC will only call it to output filenames to
 the assembler source.  So you can use it to canonicalize the format
 of the filename using this macro.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fNAMED_005fSECTION"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_NAMED_SECTION</strong> <em>(const char *<var>name</var>, unsigned int <var>flags</var>, tree <var>decl</var>)</em></dt>
 <dd><p>Output assembly directives to switch to section <var>name</var>.  The section
 should have attributes as specified by <var>flags</var>, which is a bit mask
 of the <code>SECTION_*</code> flags defined in <samp>output.h</samp>.  If <var>decl</var>
 is non-NULL, it is the <code>VAR_DECL</code> or <code>FUNCTION_DECL</code> with which
 this section is associated.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fFUNCTION_005fSECTION"></a>Target Hook: <em>section *</em> <strong>TARGET_ASM_FUNCTION_SECTION</strong> <em>(tree <var>decl</var>, enum node_frequency <var>freq</var>, bool <var>startup</var>, bool <var>exit</var>)</em></dt>
 <dd><p>Return preferred text (sub)section for function <var>decl</var>.
 Main purpose of this function is to separate cold, normal and hot
 functions. <var>startup</var> is true when function is known to be used only
 at startup (from static constructors or it is <code>main()</code>).
 <var>exit</var> is true when function is known to be used only at exit
 (from static destructors).
 Return NULL if function should go to default text section.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fFUNCTION_005fSWITCHED_005fTEXT_005fSECTIONS"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS</strong> <em>(FILE *<var>file</var>, tree <var>decl</var>, bool <var>new_is_cold</var>)</em></dt>
 <dd><p>Used by the target to emit any assembler directives or additional  labels needed when a function is partitioned between different  sections.  Output should be written to <var>file</var>.  The function  decl is available as <var>decl</var> and the new section is &lsquo;cold&rsquo; if  <var>new_is_cold</var> is <code>true</code>.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fHAVE_005fNAMED_005fSECTIONS"></a>Common Target Hook: <em>bool</em> <strong>TARGET_HAVE_NAMED_SECTIONS</strong></dt>
 <dd><p>This flag is true if the target supports <code>TARGET_ASM_NAMED_SECTION</code>.
 It must not be modified by command-line option processing.
 </p></dd></dl>

 <a name="TARGET_005fHAVE_005fSWITCHABLE_005fBSS_005fSECTIONS"></a><dl>
 <dt><a name="index-TARGET_005fHAVE_005fSWITCHABLE_005fBSS_005fSECTIONS"></a>Target Hook: <em>bool</em> <strong>TARGET_HAVE_SWITCHABLE_BSS_SECTIONS</strong></dt>
 <dd><p>This flag is true if we can create zeroed data by switching to a BSS
 section and then using <code>ASM_OUTPUT_SKIP</code> to allocate the space.
 This is true on most ELF targets.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fSECTION_005fTYPE_005fFLAGS"></a>Target Hook: <em>unsigned int</em> <strong>TARGET_SECTION_TYPE_FLAGS</strong> <em>(tree <var>decl</var>, const char *<var>name</var>, int <var>reloc</var>)</em></dt>
 <dd><p>Choose a set of section attributes for use by <code>TARGET_ASM_NAMED_SECTION</code>
 based on a variable or function decl, a section name, and whether or not the
 declaration&rsquo;s initializer may contain runtime relocations.  <var>decl</var> may be
 null, in which case read-write data should be assumed.
 </p>
 <p>The default version of this function handles choosing code vs data,
 read-only vs read-write data, and <code>flag_pic</code>.  You should only
 need to override this if your target has special flags that might be
 set via <code>__attribute__</code>.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fRECORD_005fGCC_005fSWITCHES"></a>Target Hook: <em>int</em> <strong>TARGET_ASM_RECORD_GCC_SWITCHES</strong> <em>(print_switch_type <var>type</var>, const char *<var>text</var>)</em></dt>
 <dd><p>Provides the target with the ability to record the gcc command line
 switches that have been passed to the compiler, and options that are
 enabled.  The <var>type</var> argument specifies what is being recorded.
 It can take the following values:
 </p>
 <dl compact="compact">
 <dt><code>SWITCH_TYPE_PASSED</code></dt>
 <dd><p><var>text</var> is a command line switch that has been set by the user.
 </p>
 </dd>
 <dt><code>SWITCH_TYPE_ENABLED</code></dt>
 <dd><p><var>text</var> is an option which has been enabled.  This might be as a
 direct result of a command line switch, or because it is enabled by
 default or because it has been enabled as a side effect of a different
 command line switch.  For example, the <samp>-O2</samp> switch enables
 various different individual optimization passes.
 </p>
 </dd>
 <dt><code>SWITCH_TYPE_DESCRIPTIVE</code></dt>
 <dd><p><var>text</var> is either NULL or some descriptive text which should be
 ignored.  If <var>text</var> is NULL then it is being used to warn the
 target hook that either recording is starting or ending.  The first
 time <var>type</var> is SWITCH_TYPE_DESCRIPTIVE and <var>text</var> is NULL, the
 warning is for start up and the second time the warning is for
 wind down.  This feature is to allow the target hook to make any
 necessary preparations before it starts to record switches and to
 perform any necessary tidying up after it has finished recording
 switches.
 </p>
 </dd>
 <dt><code>SWITCH_TYPE_LINE_START</code></dt>
 <dd><p>This option can be ignored by this target hook.
 </p>
 </dd>
 <dt><code>SWITCH_TYPE_LINE_END</code></dt>
 <dd><p>This option can be ignored by this target hook.
 </p></dd>
 </dl>

 <p>The hook&rsquo;s return value must be zero.  Other return values may be
 supported in the future.
 </p>
 <p>By default this hook is set to NULL, but an example implementation is
 provided for ELF based targets.  Called <var>elf_record_gcc_switches</var>,
 it records the switches as ASCII text inside a new, string mergeable
 section in the assembler output file.  The name of the new section is
 provided by the <code>TARGET_ASM_RECORD_GCC_SWITCHES_SECTION</code> target
 hook.
 </p></dd></dl>

 <dl>
 <dt><a name="index-TARGET_005fASM_005fRECORD_005fGCC_005fSWITCHES_005fSECTION"></a>Target Hook: <em>const char *</em> <strong>TARGET_ASM_RECORD_GCC_SWITCHES_SECTION</strong></dt>
 <dd><p>This is the name of the section that will be created by the example
 ELF implementation of the <code>TARGET_ASM_RECORD_GCC_SWITCHES</code> target
 hook.
 </p></dd></dl>

 <hr>
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 Next: <a href="Data-Output.html#Data-Output" accesskey="n" rel="next">Data Output</a>, Up: <a href="Assembler-Format.html#Assembler-Format" accesskey="u" rel="up">Assembler Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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	<a name="File-Framework"></a>
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	<p>
	Next: <a href="Data-Output.html#Data-Output" accesskey="n" rel="next">Data Output</a>, Up: <a href="Assembler-Format.html#Assembler-Format" accesskey="u" rel="up">Assembler Format</a>   [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
	</div>
	<hr>
	<a name="The-Overall-Framework-of-an-Assembler-File"></a>
	<h4 class="subsection">17.21.1 The Overall Framework of an Assembler File</h4>
	<a name="index-assembler-format"></a>
	<a name="index-output-of-assembler-code"></a>

	<p>This describes the overall framework of an assembly file.
	</p>
	<a name="index-default_005ffile_005fstart"></a>
	<dl>
	<dt><a name="index-TARGET_005fASM_005fFILE_005fSTART"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_FILE_START</strong> <em>(void)</em></dt>
	<dd><p>Output to <code>asm_out_file</code> any text which the assembler expects to
	find at the beginning of a file. The default behavior is controlled
	by two flags, documented below. Unless your target’s assembler is
	quite unusual, if you override the default, you should call
	<code>default_file_start</code> at some point in your target hook. This
	lets other target files rely on these variables.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fFILE_005fSTART_005fAPP_005fOFF"></a>Target Hook: <em>bool</em> <strong>TARGET_ASM_FILE_START_APP_OFF</strong></dt>
	<dd><p>If this flag is true, the text of the macro <code>ASM_APP_OFF</code> will be
	printed as the very first line in the assembly file, unless
	<samp>-fverbose-asm</samp> is in effect. (If that macro has been defined
	to the empty string, this variable has no effect.) With the normal
	definition of <code>ASM_APP_OFF</code>, the effect is to notify the GNU
	assembler that it need not bother stripping comments or extra
	whitespace from its input. This allows it to work a bit faster.
	</p>
	<p>The default is false. You should not set it to true unless you have
	verified that your port does not generate any extra whitespace or
	comments that will cause GAS to issue errors in NO_APP mode.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fFILE_005fSTART_005fFILE_005fDIRECTIVE"></a>Target Hook: <em>bool</em> <strong>TARGET_ASM_FILE_START_FILE_DIRECTIVE</strong></dt>
	<dd><p>If this flag is true, <code>output_file_directive</code> will be called
	for the primary source file, immediately after printing
	<code>ASM_APP_OFF</code> (if that is enabled). Most ELF assemblers expect
	this to be done. The default is false.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fFILE_005fEND"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_FILE_END</strong> <em>(void)</em></dt>
	<dd><p>Output to <code>asm_out_file</code> any text which the assembler expects
	to find at the end of a file. The default is to output nothing.
	</p></dd></dl>

	<dl>
	<dt><a name="index-file_005fend_005findicate_005fexec_005fstack"></a>Function: <em>void</em> <strong>file_end_indicate_exec_stack</strong> <em>()</em></dt>
	<dd><p>Some systems use a common convention, the ‘<samp>.note.GNU-stack</samp>’
	special section, to indicate whether or not an object file relies on
	the stack being executable. If your system uses this convention, you
	should define <code>TARGET_ASM_FILE_END</code> to this function. If you
	need to do other things in that hook, have your hook function call
	this function.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fLTO_005fSTART"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_LTO_START</strong> <em>(void)</em></dt>
	<dd><p>Output to <code>asm_out_file</code> any text which the assembler expects
	to find at the start of an LTO section. The default is to output
	nothing.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fLTO_005fEND"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_LTO_END</strong> <em>(void)</em></dt>
	<dd><p>Output to <code>asm_out_file</code> any text which the assembler expects
	to find at the end of an LTO section. The default is to output
	nothing.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fCODE_005fEND"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_CODE_END</strong> <em>(void)</em></dt>
	<dd><p>Output to <code>asm_out_file</code> any text which is needed before emitting
	unwind info and debug info at the end of a file. Some targets emit
	here PIC setup thunks that cannot be emitted at the end of file,
	because they couldn’t have unwind info then. The default is to output
	nothing.
	</p></dd></dl>

	<dl>
	<dt><a name="index-ASM_005fCOMMENT_005fSTART"></a>Macro: <strong>ASM_COMMENT_START</strong></dt>
	<dd><p>A C string constant describing how to begin a comment in the target
	assembler language. The compiler assumes that the comment will end at
	the end of the line.
	</p></dd></dl>

	<dl>
	<dt><a name="index-ASM_005fAPP_005fON"></a>Macro: <strong>ASM_APP_ON</strong></dt>
	<dd><p>A C string constant for text to be output before each <code>asm</code>
	statement or group of consecutive ones. Normally this is
	<code>"#APP"</code>, which is a comment that has no effect on most
	assemblers but tells the GNU assembler that it must check the lines
	that follow for all valid assembler constructs.
	</p></dd></dl>

	<dl>
	<dt><a name="index-ASM_005fAPP_005fOFF"></a>Macro: <strong>ASM_APP_OFF</strong></dt>
	<dd><p>A C string constant for text to be output after each <code>asm</code>
	statement or group of consecutive ones. Normally this is
	<code>"#NO_APP"</code>, which tells the GNU assembler to resume making the
	time-saving assumptions that are valid for ordinary compiler output.
	</p></dd></dl>

	<dl>
	<dt><a name="index-ASM_005fOUTPUT_005fSOURCE_005fFILENAME"></a>Macro: <strong>ASM_OUTPUT_SOURCE_FILENAME</strong> <em>(<var>stream</var>, <var>name</var>)</em></dt>
	<dd><p>A C statement to output COFF information or DWARF debugging information
	which indicates that filename <var>name</var> is the current source file to
	the stdio stream <var>stream</var>.
	</p>
	<p>This macro need not be defined if the standard form of output
	for the file format in use is appropriate.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fOUTPUT_005fSOURCE_005fFILENAME"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_OUTPUT_SOURCE_FILENAME</strong> <em>(FILE <var>file</var>, const char <var>name</var>)</em></dt>
	<dd><p>Output COFF information or DWARF debugging information which indicates that filename <var>name</var> is the current source file to the stdio stream <var>file</var>.
	</p>
	<p>This target hook need not be defined if the standard form of output for the file format in use is appropriate.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fOUTPUT_005fIDENT"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_OUTPUT_IDENT</strong> <em>(const char *<var>name</var>)</em></dt>
	<dd><p>Output a string based on <var>name</var>, suitable for the ‘<samp>#ident</samp>’ directive, or the equivalent directive or pragma in non-C-family languages. If this hook is not defined, nothing is output for the ‘<samp>#ident</samp>’ directive.
	</p></dd></dl>

	<dl>
	<dt><a name="index-OUTPUT_005fQUOTED_005fSTRING"></a>Macro: <strong>OUTPUT_QUOTED_STRING</strong> <em>(<var>stream</var>, <var>string</var>)</em></dt>
	<dd><p>A C statement to output the string <var>string</var> to the stdio stream
	<var>stream</var>. If you do not call the function <code>output_quoted_string</code>
	in your config files, GCC will only call it to output filenames to
	the assembler source. So you can use it to canonicalize the format
	of the filename using this macro.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fNAMED_005fSECTION"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_NAMED_SECTION</strong> <em>(const char *<var>name</var>, unsigned int <var>flags</var>, tree <var>decl</var>)</em></dt>
	<dd><p>Output assembly directives to switch to section <var>name</var>. The section
	should have attributes as specified by <var>flags</var>, which is a bit mask
	of the <code>SECTION_*</code> flags defined in <samp>output.h</samp>. If <var>decl</var>
	is non-NULL, it is the <code>VAR_DECL</code> or <code>FUNCTION_DECL</code> with which
	this section is associated.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fFUNCTION_005fSECTION"></a>Target Hook: <em>section *</em> <strong>TARGET_ASM_FUNCTION_SECTION</strong> <em>(tree <var>decl</var>, enum node_frequency <var>freq</var>, bool <var>startup</var>, bool <var>exit</var>)</em></dt>
	<dd><p>Return preferred text (sub)section for function <var>decl</var>.
	Main purpose of this function is to separate cold, normal and hot
	functions. <var>startup</var> is true when function is known to be used only
	at startup (from static constructors or it is <code>main()</code>).
	<var>exit</var> is true when function is known to be used only at exit
	(from static destructors).
	Return NULL if function should go to default text section.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fFUNCTION_005fSWITCHED_005fTEXT_005fSECTIONS"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS</strong> <em>(FILE *<var>file</var>, tree <var>decl</var>, bool <var>new_is_cold</var>)</em></dt>
	<dd><p>Used by the target to emit any assembler directives or additional labels needed when a function is partitioned between different sections. Output should be written to <var>file</var>. The function decl is available as <var>decl</var> and the new section is ‘cold’ if <var>new_is_cold</var> is <code>true</code>.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fHAVE_005fNAMED_005fSECTIONS"></a>Common Target Hook: <em>bool</em> <strong>TARGET_HAVE_NAMED_SECTIONS</strong></dt>
	<dd><p>This flag is true if the target supports <code>TARGET_ASM_NAMED_SECTION</code>.
	It must not be modified by command-line option processing.
	</p></dd></dl>

	<a name="TARGET_005fHAVE_005fSWITCHABLE_005fBSS_005fSECTIONS"></a><dl>
	<dt><a name="index-TARGET_005fHAVE_005fSWITCHABLE_005fBSS_005fSECTIONS"></a>Target Hook: <em>bool</em> <strong>TARGET_HAVE_SWITCHABLE_BSS_SECTIONS</strong></dt>
	<dd><p>This flag is true if we can create zeroed data by switching to a BSS
	section and then using <code>ASM_OUTPUT_SKIP</code> to allocate the space.
	This is true on most ELF targets.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fSECTION_005fTYPE_005fFLAGS"></a>Target Hook: <em>unsigned int</em> <strong>TARGET_SECTION_TYPE_FLAGS</strong> <em>(tree <var>decl</var>, const char *<var>name</var>, int <var>reloc</var>)</em></dt>
	<dd><p>Choose a set of section attributes for use by <code>TARGET_ASM_NAMED_SECTION</code>
	based on a variable or function decl, a section name, and whether or not the
	declaration’s initializer may contain runtime relocations. <var>decl</var> may be
	null, in which case read-write data should be assumed.
	</p>
	<p>The default version of this function handles choosing code vs data,
	read-only vs read-write data, and <code>flag_pic</code>. You should only
	need to override this if your target has special flags that might be
	set via <code>__attribute__</code>.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fRECORD_005fGCC_005fSWITCHES"></a>Target Hook: <em>int</em> <strong>TARGET_ASM_RECORD_GCC_SWITCHES</strong> <em>(print_switch_type <var>type</var>, const char *<var>text</var>)</em></dt>
	<dd><p>Provides the target with the ability to record the gcc command line
	switches that have been passed to the compiler, and options that are
	enabled. The <var>type</var> argument specifies what is being recorded.
	It can take the following values:
	</p>
	<dl compact="compact">
	<dt><code>SWITCH_TYPE_PASSED</code></dt>
	<dd><p><var>text</var> is a command line switch that has been set by the user.
	</p>
	</dd>
	<dt><code>SWITCH_TYPE_ENABLED</code></dt>
	<dd><p><var>text</var> is an option which has been enabled. This might be as a
	direct result of a command line switch, or because it is enabled by
	default or because it has been enabled as a side effect of a different
	command line switch. For example, the <samp>-O2</samp> switch enables
	various different individual optimization passes.
	</p>
	</dd>
	<dt><code>SWITCH_TYPE_DESCRIPTIVE</code></dt>
	<dd><p><var>text</var> is either NULL or some descriptive text which should be
	ignored. If <var>text</var> is NULL then it is being used to warn the
	target hook that either recording is starting or ending. The first
	time <var>type</var> is SWITCH_TYPE_DESCRIPTIVE and <var>text</var> is NULL, the
	warning is for start up and the second time the warning is for
	wind down. This feature is to allow the target hook to make any
	necessary preparations before it starts to record switches and to
	perform any necessary tidying up after it has finished recording
	switches.
	</p>
	</dd>
	<dt><code>SWITCH_TYPE_LINE_START</code></dt>
	<dd><p>This option can be ignored by this target hook.
	</p>
	</dd>
	<dt><code>SWITCH_TYPE_LINE_END</code></dt>
	<dd><p>This option can be ignored by this target hook.
	</p></dd>
	</dl>

	<p>The hook’s return value must be zero. Other return values may be
	supported in the future.
	</p>
	<p>By default this hook is set to NULL, but an example implementation is
	provided for ELF based targets. Called <var>elf_record_gcc_switches</var>,
	it records the switches as ASCII text inside a new, string mergeable
	section in the assembler output file. The name of the new section is
	provided by the <code>TARGET_ASM_RECORD_GCC_SWITCHES_SECTION</code> target
	hook.
	</p></dd></dl>

	<dl>
	<dt><a name="index-TARGET_005fASM_005fRECORD_005fGCC_005fSWITCHES_005fSECTION"></a>Target Hook: <em>const char *</em> <strong>TARGET_ASM_RECORD_GCC_SWITCHES_SECTION</strong></dt>
	<dd><p>This is the name of the section that will be created by the example
	ELF implementation of the <code>TARGET_ASM_RECORD_GCC_SWITCHES</code> target
	hook.
	</p></dd></dl>

	<hr>
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