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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - No inline debug info generated for small functions when optimizing"
href="https://llvm.org/bugs/show_bug.cgi?id=25630">25630</a>
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<th>Summary</th>
<td>No inline debug info generated for small functions when optimizing
</td>
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<th>Product</th>
<td>new-bugs
</td>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>dnovillo@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>danielcdh@gmail.com, dblaikie@gmail.com, echristo@gmail.com, llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=15349" name="attach_15349" title="Test case">attachment 15349</a> <a href="attachment.cgi?id=15349&action=edit" title="Test case">[details]</a></span>
Test case
For one liner functions, LLVM seems to not be emitting inlined-at information
in the final binary. The inlinedAt tags are there in the bytecode, but don't
show up in the final binary.
If I change the code of the inlined function to have more than one line, then
the inlinedAt markers survive to the final binary.
$ clang++ -O2 -g bug.cc -o bug
$ llvm-dwarfdump --debug-dump=info bug|grep -A6 DW_TAG_inlined_subroutine
When compiled with GCC, the inlined function is marked properly:
$ g++-4.9 -O2 -g bug.cc -o gcc-bug
$ llvm-dwarfdump --debug-dump=info gcc-bug|grep -A6 DW_TAG_inlined_subroutine
0x00000476: DW_TAG_inlined_subroutine [21] *
DW_AT_abstract_origin [DW_FORM_ref4] (cu + 0x028d =>
{0x000003da} "_Z3sumxx")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000400559)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000003)
DW_AT_call_file [DW_FORM_data1] ("./bug.cc")
DW_AT_call_line [DW_FORM_data1] (8)
DW_AT_GNU_discriminator [DW_FORM_data1] (0x02)
If I modified the inlined function to have more code, LLVM will generate a
DW_TAG_inlined_subroutine tag. I did this in the no-bug.cc test case:
$ clang++ -g -O2 no-bug.cc -o no-bug
$ llvm-dwarfdump --debug-dump=info no-bug|grep -A6 DW_TAG_inlined_subroutine
0x000000b1: DW_TAG_inlined_subroutine [9] *
DW_AT_abstract_origin [DW_FORM_ref4] (cu + 0x004c =>
{0x0000004c} "_Z3sumxx")
DW_AT_low_pc [DW_FORM_addr] (0x000000000040063e)
DW_AT_high_pc [DW_FORM_data4] (0x00000010)
DW_AT_call_file [DW_FORM_data1] ("./no-bug.cc")
DW_AT_call_line [DW_FORM_data1] (13)
DW_AT_GNU_discriminator [DW_FORM_data1] (0x01)</pre>
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