Commit Graph

9 Commits

Author SHA1 Message Date
Jeremy Morse ed29dbaafa [DebugInfo] Remove some users of DBG_VALUEs IsIndirect field
This patch kills off a significant user of the "IsIndirect" field of
DBG_VALUE machine insts. Brought up in in PR41675, IsIndirect is
techncally redundant as it can be expressed by the DIExpression of a
DBG_VALUE inst, and it isn't helpful to have two ways of expressing
things.

Rather than setting IsIndirect, have DBG_VALUE creators add an extra deref
to the insts DIExpression. There should now be no appearences of
IsIndirect=True from isel down to LiveDebugVariables / VirtRegRewriter,
which is ensured by an assertion in LDVImpl::handleDebugValue. This means
we also get to delete the IsIndirect handling in LiveDebugVariables. Tests
can be upgraded by for example swapping the following IsIndirect=True
DBG_VALUE:

  DBG_VALUE $somereg, 0, !123, !DIExpression(DW_OP_foo)

With one where the indirection is in the DIExpression, by _appending_
a deref:

  DBG_VALUE $somereg, $noreg, !123, !DIExpression(DW_OP_foo, DW_OP_deref)

Which both mean the same thing. 

Most of the test changes in this patch are updates of that form; also some
changes in how the textual assembly printer handles these insts.

Differential Revision: https://reviews.llvm.org/D68945

llvm-svn: 374877
2019-10-15 10:46:24 +00:00
Shiva Chen 2c864551df [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is

!DILabel(scope: !1, name: "foo", file: !2, line: 3)

We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is

llvm.dbg.label(metadata !1)

It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.

We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.

Differential Revision: https://reviews.llvm.org/D45024

Patch by Hsiangkai Wang.

llvm-svn: 331841
2018-05-09 02:40:45 +00:00
Puyan Lotfi 43e94b15ea Followup on Proposal to move MIR physical register namespace to '$' sigil.
Discussed here:

http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html

In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.

llvm-svn: 323922
2018-01-31 22:04:26 +00:00
Francis Visoiu Mistrih 9d7bb0cb40 [CodeGen] Print register names in lowercase in both MIR and debug output
As part of the unification of the debug format and the MIR format,
always print registers as lowercase.

* Only debug printing is affected. It now follows MIR.

Differential Revision: https://reviews.llvm.org/D40417

llvm-svn: 319187
2017-11-28 17:15:09 +00:00
Reid Kleckner 4e04028791 Re-land "[DebugInfo] Insert DW_OP_deref when spilling indirect DBG_VALUEs"
After r313775, it's easier to maintain a parallel BitVector of spilled
locations indexed by location number.

I wasn't able to build a good reduced test case for this iteration of
the bug, but I added a more direct assertion that spilled values must
use frame index locations. If this bug reappears, it won't only fire on
the NEON vector code that we detected it on, but on medium-sized
integer-only programs as well.

llvm-svn: 313786
2017-09-20 18:19:08 +00:00
Reid Kleckner ffdf087499 Revert "[DebugInfo] Insert DW_OP_deref when spilling indirect DBG_VALUEs"
This reverts r313640, originally r313400, one more time for essentially
the same issue. My BitVector of spilled location numbers isn't working
because we coalesce identical DBG_VALUE locations as we rewrite them,
invalidating the location numbers used to index the BitVector.

llvm-svn: 313679
2017-09-19 21:18:32 +00:00
Reid Kleckner 86c74dd791 Re-land r313400 "[DebugInfo] Insert DW_OP_deref when spilling indirect DBG_VALUEs"
I forgot to zero out the BitVector when reusing it between UserValues.

Later uses of the same location number for a different UserValue would
falsely indicate that they were spilled. Usually this would lead to
incorrect debug info, but in some cases they would indicate something
nonsensical like a memory location based on a vector register (Q8 on
ARM).

llvm-svn: 313640
2017-09-19 16:32:15 +00:00
Hans Wennborg 4de620ab3d Revert r313400 "[DebugInfo] Insert DW_OP_deref when spilling indirect DBG_VALUEs"
This caused asserts in Chromium. See http://crbug.com/766261

> Summary:
> This comes up in optimized debug info for C++ programs that pass and
> return objects indirectly by address. In these programs,
> llvm.dbg.declare survives optimization, which causes us to emit indirect
> DBG_VALUE instructions. The fast register allocator knows to insert
> DW_OP_deref when spilling indirect DBG_VALUE instructions, but the
> LiveDebugVariables did not until this change.
>
> This fixes part of PR34513. I need to look into why this doesn't work at
> -O0 and I'll send follow up patches to handle that.
>
> Reviewers: aprantl, dblaikie, probinson
>
> Subscribers: qcolombet, hiraditya, llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D37911

llvm-svn: 313589
2017-09-18 23:08:42 +00:00
Reid Kleckner 3a66c1cb58 [DebugInfo] Insert DW_OP_deref when spilling indirect DBG_VALUEs
Summary:
This comes up in optimized debug info for C++ programs that pass and
return objects indirectly by address. In these programs,
llvm.dbg.declare survives optimization, which causes us to emit indirect
DBG_VALUE instructions. The fast register allocator knows to insert
DW_OP_deref when spilling indirect DBG_VALUE instructions, but the
LiveDebugVariables did not until this change.

This fixes part of PR34513. I need to look into why this doesn't work at
-O0 and I'll send follow up patches to handle that.

Reviewers: aprantl, dblaikie, probinson

Subscribers: qcolombet, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D37911

llvm-svn: 313400
2017-09-15 21:54:38 +00:00