emit debug info for labels

[dwblaikie]

Bugzilla Link	14500
Resolution	FIXED
Resolved on	Sep 05, 2019 15:16
Version	trunk
OS	Linux
Blocks	#14702 llvm/llvm-bugzilla-archive#24345
CC	@DougGregor,@echristo,@yuanfang-chen

Extended Description

Clang doesn't currently produce DW_TAG_labels. (see gdb.base/label.exp in the GDB 7.5 test suite)

[yuanfang-chen]

DW_TAG_label is supported since d6b2cdf.

We could close this after the XFAIL tests for this in GDB (they still exist in gdb trunk) are removed.

[dwblaikie]

DW_TAG_label is supported since d6b2cdf.

What subversion revision is this? (and/or could you provide a link to the llvm-commits list, github commit, etc)

[echristo]

commit d6b2cdf
Author: Shiva Chen [email protected]
Date: Tue Jul 24 02:22:55 2018 +0000

[DebugInfo] Generate DWARF debug information for labels.

There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

We will collect label information from DBG_LABEL. Before every DBG_LABEL,
we will generate a temporary symbol to denote the location of the label.
The symbol could be used to get DW_AT_low_pc afterwards. So, we create a
mapping between 'inlined label' and DBG_LABEL MachineInstr in DebugHandlerBase.
The DBG_LABEL in the mapping is used to query the symbol before it.

The AbstractLabels in DwarfCompileUnit is used to process labels in inlined
functions.

We also keep a mapping between scope and labels in DwarfFile to help to
generate correct tree structure of DIEs.

Differential Revision: https://reviews.llvm.org/D45556

Patch by Hsiangkai Wang.

llvm-svn: 337799

[dwblaikie]

SGTM then - thanks!

[yuanfang-chen]

Thank you all.

Hi David, do you plan to revert the test workaround on the GDB side?

[dwblaikie]

Thank you all.

Hi David, do you plan to revert the test workaround on the GDB side?

Sure - I sent a patch to the gdb list for review.

[llvmbot]

mentioned in issue llvm/llvm-bugzilla-archive#24345

[llvmbot]

@llvm/issue-subscribers-debuginfo

Author: David Blaikie (dwblaikie)

| | | | --- | --- | | Bugzilla Link | [14500](https://llvm.org/bz14500) | | Resolution | FIXED | | Resolved on | Sep 05, 2019 15:16 | | Version | trunk | | OS | Linux | | Blocks | llvm/llvm-project#14702 llvm/llvm-bugzilla-archive#24345 | | CC | @DougGregor,@echristo,@yuanfang-chen |

Extended Description

Clang doesn't currently produce DW_TAG_labels. (see gdb.base/label.exp in the GDB 7.5 test suite)