https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69787
Bug ID: 69787
Summary: class only emitted as declaration in DWARF
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: tromey at gcc dot gnu.org
Target Milestone: ---
Created attachment 37673
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37673&action=edit
reduced test case
This is a debug info issue reduced from a firefox bug:
https://bugzilla.mozilla.org/show_bug.cgi?id=1247769
This is similar to bug 12385, but different.
Consider the attached test case.
For this test we want to be able to see the debug info for
"TheOneWeWant".
If I compile the test with -g, I get the debug info:
<1><52>: Abbrev Number: 6 (DW_TAG_class_type)
<53> DW_AT_name : (indirect string, offset: 0x79): TheOneWeWant
<57> DW_AT_byte_size : 1
<58> DW_AT_decl_file : 1
<59> DW_AT_decl_line : 27
<5a> DW_AT_sibling : <0x79>
However, if I compile with "-g -DFAIL", the class is only emitted
as a declaration, causing gdb to ignore it:
<1><84>: Abbrev Number: 9 (DW_TAG_class_type)
<85> DW_AT_name : (indirect string, offset: 0x79): TheOneWeWant
<89> DW_AT_declaration : 1
<89> DW_AT_sibling : <0xa1>
There doesn't seem to be any notable difference, to me, between the
success and fail cases here. I think g++ ought to emit full debug info
for this class in both cases.
Also, it would be great if the rules for when debug info for a class
is emitted would be documented. There are some flags documented
(-femit-class-debug-always and -fno-eliminate-unused-debug-types -- though
note these are separated widely in the info node, which is odd by itself);
and there is some information about other quasi-related things in the
"Vague Linkage" node; and one parenthetical mention in the "#pragma interface"
node. In the current situation it's unclear to me what I can do in order
to get the debug info here.
