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<a name="DWARF"></a>
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<a name="Macros-for-DWARF-Output"></a>
<h4 class="subsection">18.21.5 Macros for DWARF Output</h4>

<p>Here are macros for DWARF output.
</p>
<dl>
<dt><a name="index-DWARF2_005fDEBUGGING_005fINFO"></a>Macro: <strong>DWARF2_DEBUGGING_INFO</strong></dt>
<dd><p>Define this macro if GCC should produce dwarf version 2 format
debugging output in response to the <samp>-g</samp> option.
</p>
<dl>
<dt><a name="index-TARGET_005fDWARF_005fCALLING_005fCONVENTION"></a>Target Hook: <em>int</em> <strong>TARGET_DWARF_CALLING_CONVENTION</strong> <em>(const_tree <var>function</var>)</em></dt>
<dd><p>Define this to enable the dwarf attribute <code>DW_AT_calling_convention</code> to
be emitted for each function.  Instead of an integer return the enum
value for the <code>DW_CC_</code> tag.
</p></dd></dl>

<p>To support optional call frame debugging information, you must also
define <code>INCOMING_RETURN_ADDR_RTX</code> and either set
<code>RTX_FRAME_RELATED_P</code> on the prologue insns if you use RTL for the
prologue, or call <code>dwarf2out_def_cfa</code> and <code>dwarf2out_reg_save</code>
as appropriate from <code>TARGET_ASM_FUNCTION_PROLOGUE</code> if you don&rsquo;t.
</p></dd></dl>

<dl>
<dt><a name="index-DWARF2_005fFRAME_005fINFO"></a>Macro: <strong>DWARF2_FRAME_INFO</strong></dt>
<dd><p>Define this macro to a nonzero value if GCC should always output
Dwarf 2 frame information.  If <code>TARGET_EXCEPT_UNWIND_INFO</code>
(see <a href="Exception-Region-Output.html#Exception-Region-Output">Exception Region Output</a>) returns <code>UI_DWARF2</code>, and
exceptions are enabled, GCC will output this information not matter
how you define <code>DWARF2_FRAME_INFO</code>.
</p></dd></dl>

<dl>
<dt><a name="index-TARGET_005fDEBUG_005fUNWIND_005fINFO"></a>Target Hook: <em>enum unwind_info_type</em> <strong>TARGET_DEBUG_UNWIND_INFO</strong> <em>(void)</em></dt>
<dd><p>This hook defines the mechanism that will be used for describing frame
unwind information to the debugger.  Normally the hook will return
<code>UI_DWARF2</code> if DWARF 2 debug information is enabled, and
return <code>UI_NONE</code> otherwise.
</p>
<p>A target may return <code>UI_DWARF2</code> even when DWARF 2 debug information
is disabled in order to always output DWARF 2 frame information.
</p>
<p>A target may return <code>UI_TARGET</code> if it has ABI specified unwind tables.
This will suppress generation of the normal debug frame unwind information.
</p></dd></dl>

<dl>
<dt><a name="index-DWARF2_005fASM_005fLINE_005fDEBUG_005fINFO"></a>Macro: <strong>DWARF2_ASM_LINE_DEBUG_INFO</strong></dt>
<dd><p>Define this macro to be a nonzero value if the assembler can generate Dwarf 2
line debug info sections.  This will result in much more compact line number
tables, and hence is desirable if it works.
</p></dd></dl>

<dl>
<dt><a name="index-DWARF2_005fASM_005fVIEW_005fDEBUG_005fINFO"></a>Macro: <strong>DWARF2_ASM_VIEW_DEBUG_INFO</strong></dt>
<dd><p>Define this macro to be a nonzero value if the assembler supports view
assignment and verification in <code>.loc</code>.  If it does not, but the
user enables location views, the compiler may have to fallback to
internal line number tables.
</p></dd></dl>

<dl>
<dt><a name="index-TARGET_005fRESET_005fLOCATION_005fVIEW"></a>Target Hook: <em>int</em> <strong>TARGET_RESET_LOCATION_VIEW</strong> <em>(rtx_insn *<var></var>)</em></dt>
<dd><p>This hook, if defined, enables -ginternal-reset-location-views, and
uses its result to override cases in which the estimated min insn
length might be nonzero even when a PC advance (i.e., a view reset)
cannot be taken for granted.
</p>
<p>If the hook is defined, it must return a positive value to indicate
the insn definitely advances the PC, and so the view number can be
safely assumed to be reset; a negative value to mean the insn
definitely does not advance the PC, and os the view number must not
be reset; or zero to decide based on the estimated insn length.
</p>
<p>If insn length is to be regarded as reliable, set the hook to
<code>hook_int_rtx_insn_0</code>.
</p></dd></dl>

<dl>
<dt><a name="index-TARGET_005fWANT_005fDEBUG_005fPUB_005fSECTIONS"></a>Target Hook: <em>bool</em> <strong>TARGET_WANT_DEBUG_PUB_SECTIONS</strong></dt>
<dd><p>True if the <code>.debug_pubtypes</code> and <code>.debug_pubnames</code> sections should be emitted.  These sections are not used on most platforms, and in particular GDB does not use them.
</p></dd></dl>

<dl>
<dt><a name="index-TARGET_005fDELAY_005fSCHED2"></a>Target Hook: <em>bool</em> <strong>TARGET_DELAY_SCHED2</strong></dt>
<dd><p>True if sched2 is not to be run at its normal place.
This usually means it will be run as part of machine-specific reorg.
</p></dd></dl>

<dl>
<dt><a name="index-TARGET_005fDELAY_005fVARTRACK"></a>Target Hook: <em>bool</em> <strong>TARGET_DELAY_VARTRACK</strong></dt>
<dd><p>True if vartrack is not to be run at its normal place.
This usually means it will be run as part of machine-specific reorg.
</p></dd></dl>

<dl>
<dt><a name="index-TARGET_005fNO_005fREGISTER_005fALLOCATION"></a>Target Hook: <em>bool</em> <strong>TARGET_NO_REGISTER_ALLOCATION</strong></dt>
<dd><p>True if register allocation and the passes
following it should not be run.  Usually true only for virtual assembler
targets.
</p></dd></dl>

<dl>
<dt><a name="index-ASM_005fOUTPUT_005fDWARF_005fDELTA"></a>Macro: <strong>ASM_OUTPUT_DWARF_DELTA</strong> <em>(<var>stream</var>, <var>size</var>, <var>label1</var>, <var>label2</var>)</em></dt>
<dd><p>A C statement to issue assembly directives that create a difference
<var>lab1</var> minus <var>lab2</var>, using an integer of the given <var>size</var>.
</p></dd></dl>

<dl>
<dt><a name="index-ASM_005fOUTPUT_005fDWARF_005fVMS_005fDELTA"></a>Macro: <strong>ASM_OUTPUT_DWARF_VMS_DELTA</strong> <em>(<var>stream</var>, <var>size</var>, <var>label1</var>, <var>label2</var>)</em></dt>
<dd><p>A C statement to issue assembly directives that create a difference
between the two given labels in system defined units, e.g. instruction
slots on IA64 VMS, using an integer of the given size.
</p></dd></dl>

<dl>
<dt><a name="index-ASM_005fOUTPUT_005fDWARF_005fOFFSET"></a>Macro: <strong>ASM_OUTPUT_DWARF_OFFSET</strong> <em>(<var>stream</var>, <var>size</var>, <var>label</var>, <var>offset</var>, <var>section</var>)</em></dt>
<dd><p>A C statement to issue assembly directives that create a
section-relative reference to the given <var>label</var> plus <var>offset</var>, using
an integer of the given <var>size</var>.  The label is known to be defined in the
given <var>section</var>.
</p></dd></dl>

<dl>
<dt><a name="index-ASM_005fOUTPUT_005fDWARF_005fPCREL"></a>Macro: <strong>ASM_OUTPUT_DWARF_PCREL</strong> <em>(<var>stream</var>, <var>size</var>, <var>label</var>)</em></dt>
<dd><p>A C statement to issue assembly directives that create a self-relative
reference to the given <var>label</var>, using an integer of the given <var>size</var>.
</p></dd></dl>

<dl>
<dt><a name="index-ASM_005fOUTPUT_005fDWARF_005fDATAREL"></a>Macro: <strong>ASM_OUTPUT_DWARF_DATAREL</strong> <em>(<var>stream</var>, <var>size</var>, <var>label</var>)</em></dt>
<dd><p>A C statement to issue assembly directives that create a reference to the
given <var>label</var> relative to the dbase, using an integer of the given <var>size</var>.
</p></dd></dl>

<dl>
<dt><a name="index-ASM_005fOUTPUT_005fDWARF_005fTABLE_005fREF"></a>Macro: <strong>ASM_OUTPUT_DWARF_TABLE_REF</strong> <em>(<var>label</var>)</em></dt>
<dd><p>A C statement to issue assembly directives that create a reference to
the DWARF table identifier <var>label</var> from the current section.  This
is used on some systems to avoid garbage collecting a DWARF table which
is referenced by a function.
</p></dd></dl>

<dl>
<dt><a name="index-TARGET_005fASM_005fOUTPUT_005fDWARF_005fDTPREL"></a>Target Hook: <em>void</em> <strong>TARGET_ASM_OUTPUT_DWARF_DTPREL</strong> <em>(FILE *<var>file</var>, int <var>size</var>, rtx <var>x</var>)</em></dt>
<dd><p>If defined, this target hook is a function which outputs a DTP-relative
reference to the given TLS symbol of the specified size.
</p></dd></dl>

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