708 Commits

Author SHA1 Message Date
Jeremy Morse
fa3a9f0fc7 Revert sharing subprograms across CUs
This patch is a revert of e08f205f5c2c. In that patch, DW_TAG_subprograms
were permitted to be referenced across CU boundaries, to improve stack
trace construction using call site information. Unfortunately, as
documented in PR48790, the way that subprograms are "owned" by dwarf units
is sufficiently complicated that subprograms end up in unexpected units,
invalidating cross-unit references.

There's no obvious way to easily fix this, and several attempts have
failed. Revert this to ensure correct DWARF is always emitted.

Three tests change in addition to the reversion, but they're all very
light alterations.

Differential Revision: https://reviews.llvm.org/D107076

(cherry picked from commit d4ce9e463d51b18547dbd181884046abf77c5c91)
Signed-off-by: Jeremy Morse <jeremy.morse@sony.com>

Conflicts:
	llvm/test/DebugInfo/X86/convert-loclist.ll
2021-08-23 11:18:57 -07:00
Paul Robinson
8ff9b86a65 [DebuggerTuning] Move a comment to a more useful place.
The comment about how to make use of debugger tuning within DwarfDebug
really belongs inside the DwarfDebug declaration, where it will be
easier to find.
2021-05-03 11:08:04 -07:00
Esme-Yi
353dabc855 [Debug-Info] Use inlined strings in .dwinfo section by default for DBX.
Summary: Set the default DwarfInlinedStrings as inlined strings for DBX, due to DBX does not support .dwstr section for now.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D99933
2021-04-08 07:20:22 +00:00
Jeremy Morse
102262e880 Revert "Re-land D94976 after revert in e29552c5aff6"
Maskray has reported a fault with .debug_gnu_pubnames in the comments on
D94976, caused by this patch, reverting to investigate.

This reverts commit 8998f5843503773c2f51fd475e2c77c687a65ee6.
2021-02-08 12:41:12 +00:00
Jeremy Morse
1dab9824e4 Re-land D94976 after revert in e29552c5aff6
This modified patch avoids redirecting the unit in which a subprogram is
created if type units are enabled -- DIEs were getting children allocated
from different units memory pools. Original commit message:

[DWARF] Create subprogram's DIE in DISubprogram's unit

This is a fix for PR48790. Over in D70350, subprogram DIEs were permitted
to be shared between CUs. However, the creation of a subprogram DIE can be
triggered early, from other CUs. The subprogram definition is then created
in one CU, and when the function is actually emitted children are attached
to the subprogram that expect to be in another CU. This breaks internal CU
references in the children.

Fix this by redirecting the creation of subprogram DIEs in
getOrCreateContextDIE to the CU specified by it's DISubprogram definition.
This ensures that the subprogram DIE is always created in the correct CU.

Differential Revision: https://reviews.llvm.org/D94976
2021-02-04 11:17:18 +00:00
David Blaikie
266d73d7f0 DebugInfo: Add a DWARF FORM extension for addrx+offset references to reduce relocations
This is an alternative to the use of complex DWARF expressions for
addresses - shaving off a few extra bytes of expression overhead.
2021-01-28 10:20:02 -08:00
Shaurya Gupta
e387e1d835 Revert "[DWARF] Create subprogram's DIE in DISubprogram's unit"
This reverts commit ef0dcb506300dc9644e8000c6028d14214be9d97.

This change is causing a lot of compiler crashes inside, sorry I don't have a
small repro/stacktrace with symbols to share right now.

Differential Revision: https://reviews.llvm.org/D95622
2021-01-28 16:39:01 +00:00
David Blaikie
19cd3f5c02 DebugInfo: Deduplicate addresses in debug_addr
Experimental, using non-existent DWARF support to use an expr for the
location involving an addr_index (to compute address + offset so
addresses can be reused in more places).

The global variable debug info had to be deferred until the end of the
module (so bss variables would all be emitted first - so their labels
would have the relevant section). Non-bss variables seemed to not have
their label assigned to a section even at the end of the module, so I
didn't know what to do there.

Also, the hashing code is broken - doesn't know how to hash these
expressions (& isn't hashing anything inside subprograms, which seems
problematic), so for test purposes this change just skips the hash
computation. (GCC's actually overly sensitive in its hash function, it
seems - I'm forgetting the specific case right now - anyway, we might
want to just use the frontend-known file hash and give up on optimistic
.dwo/.dwp reuse)
2021-01-27 14:00:43 -08:00
Jeremy Morse
1f513e79c9 [DWARF] Create subprogram's DIE in DISubprogram's unit
This is a fix for PR48790. Over in D70350, subprogram DIEs were permitted
to be shared between CUs. However, the creation of a subprogram DIE can be
triggered early, from other CUs. The subprogram definition is then created
in one CU, and when the function is actually emitted children are attached
to the subprogram that expect to be in another CU. This breaks internal CU
references in the children.

Fix this by redirecting the creation of subprogram DIEs in
getOrCreateContextDIE to the CU specified by it's DISubprogram definition.
This ensures that the subprogram DIE is always created in the correct CU.

Differential Revision: https://reviews.llvm.org/D94976
2021-01-27 12:36:14 +00:00
David Blaikie
fd9d683351 DebugInfo: Generalize the .debug_addr minimization flag to pave the way for including other strategies 2021-01-25 16:24:35 -08:00
David Blaikie
b2e950c063 DebugInfo: Add support for always using ranges (rather than low/high pc) in DWARFv5
Given the ability provided by DWARFv5 rnglists to reuse addresses in the
address pool, it can be advantageous to object file size to use range
encodings even when the range could be described by a direct low/high
pc.

Add a flag to allow enabling this in DWARFv5 for the purpose of
experimentation/data gathering.

It might be that it makes sense to enable this functionality by default
for DWARFv5 + Split DWARF at least, where the tradeoff/desire to
optimize for .o file size is more explicit and .o bytes are higher
priority than .dwo bytes.
2021-01-05 16:36:22 -08:00
Kazu Hirata
b3da88360d [CodeGen, Transforms] Use *Map::lookup (NFC) 2020-12-27 09:57:27 -08:00
Fangrui Song
479679999b [CodeGen] Delete 15 unused declarations
Notes about a few declarations:

* LiveVariables::RegisterDefIsDead: deleted by r47927
* createForwardControlFlowIntegrityPass, createJumpInstrTablesPass: deleted by r230780
* RegScavenger::setLiveInsUsed: deleted by r292543
* ScheduleDAGInstrs::{toggleKillFlag,startBlockForKills}: deleted by r304055
* Localizer::shouldLocalize: remnant of D75207
* DwarfDebug::addSectionLabel: deleted by r373273
2020-12-06 14:55:04 -08:00
Jameson Nash
11a667f122 make the AsmPrinterHandler array public
This lets external consumers customize the output, similar to how
AssemblyAnnotationWriter lets the caller define callbacks when printing
IR. The array of handlers already existed, this just cleans up the code
so that it can be exposed publically.

Replaces https://reviews.llvm.org/D74158

Differential Revision: https://reviews.llvm.org/D89613
2020-11-03 10:02:09 -05:00
David Blaikie
8b9f3c8506 DWARFv5: Disable DW_OP_convert for configurations that don't yet support it
Testing reveals that lldb and gdb have some problems with supporting
DW_OP_convert - gdb with Split DWARF tries to resolve the CU-relative
DIE offset relative to the skeleton DIE. lldb tries to treat the offset
as absolute, which judging by the llvm-dsymutil support for
DW_OP_convert, I guess works OK in MachO? (though probably llvm-dsymutil
is producing invalid DWARF by resolving the relative reference to an
absolute one?).

Specifically this disables DW_OP_convert usage in DWARFv5 if:
* Tuning for GDB and using Split DWARF
* Tuning for LLDB and not targeting MachO
2020-10-22 12:02:33 -07:00
Jameson Nash
fe8adca85b Revert "make the AsmPrinterHandler array public"
I messed up one of the tests.
2020-10-16 17:22:07 -04:00
Jameson Nash
310509685d make the AsmPrinterHandler array public
This lets external consumers customize the output, similar to how
AssemblyAnnotationWriter lets the caller define callbacks when printing
IR. The array of handlers already existed, this just cleans up the code
so that it can be exposed publically.

Differential Revision: https://reviews.llvm.org/D74158
2020-10-16 16:27:31 -04:00
Igor Kudrin
a68bb0aa01 [DebugInfo] Fix emitting DWARF64 compilation units (5/19).
The patch also adds a method to choose an appropriate DWARF form
to represent section offsets according to the version and the format
of producing debug info.

Differential Revision: https://reviews.llvm.org/D87014
2020-09-15 11:30:30 +07:00
OCHyams
5a27fa8d7e Revert "[DWARF] Add cuttoff guarding quadratic validThroughout behaviour"
This reverts commit b9d977b0ca60c54f11615ca9d144c9f08b29fd85.

This cutoff is no longer required. The commit 34ffa7fc501 (D86153) introduces a
performance improvement which was tested against the motivating case for this
patch.

Discussed in differential revision: https://reviews.llvm.org/D86153
2020-08-27 11:52:30 +01:00
Sourabh Singh Tomar
9241b8151b [DebugInfo][flang]Added support for representing Fortran assumed length strings
This patch adds support for representing Fortran `character(n)`.

Primarily patch is based out of D54114 with appropriate modifications.

Test case IR is generated using our downstream classic-flang. We're in process
of upstreaming flang PR's but classic-flang has dependencies on llvm, so
this has to get in first.

Patch includes functional test case for both IR and corresponding
dwarf, furthermore it has been manually tested as well using GDB.

Source snippet:
```
 program assumedLength
   call sub('Hello')
   call sub('Goodbye')
   contains
   subroutine sub(string)
           implicit none
           character(len=*), intent(in) :: string
           print *, string
   end subroutine sub
 end program assumedLength
```

GDB:
```
(gdb) ptype string
type = character (5)
(gdb) p string
$1 = 'Hello'
```

Reviewed By: aprantl, schweitz

Differential Revision: https://reviews.llvm.org/D86305
2020-08-22 10:13:40 +05:30
David Blaikie
c9c4b5ec13 Recommit "PR44685: DebugInfo: Handle address-use-invalid type units referencing non-type units"
Originally committed as be3ef93bf58aa5546c7baadfb21d43b75fbb4e24.
Reverted by b4bffdbadfcceb3959aaf231c1542301944e5812 due to bot
failures:
http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-expensive/17380/testReport/junit/LLVM/DebugInfo_X86/addr_tu_to_non_tu_ll/
http://45.33.8.238/win/22216/step_11.txt

MacOS failure due to testing Split DWARF which isn't compatible with
MachO.
Windows failure due to testing type units which aren't enabled on
Windows.

Fix both of these by applying an explicit x86 linux triple to the test.
2020-08-18 13:43:28 -07:00
Nico Weber
7f41844cac Revert "PR44685: DebugInfo: Handle address-use-invalid type units referencing non-type units"
This reverts commit be3ef93bf58aa5546c7baadfb21d43b75fbb4e24.
Test fails on macOS and Windows, e.g. http://45.33.8.238/win/22216/step_11.txt
2020-08-18 08:40:36 -04:00
David Blaikie
b29b31a4a9 PR44685: DebugInfo: Handle address-use-invalid type units referencing non-type units
Theory was that we should never reach a non-type unit (eg: type in an
anonymous namespace) when we're already in the invalid "encountered an
address-use, so stop emitting types for now, until we throw out the
whole type tree to restart emitting in non-type unit" state. But that's
not the case (prior commit cleaned up one reason this wasn't exposed
sooner - but also makes it easier to test/demonstrate this issue)
2020-08-17 21:42:00 -07:00
David Stenberg
b7e32254c6 [DebugInfo] Refactor .debug_macro checks. NFCI
Move the Dwarf version checks that determine if the .debug_macro section
should be emitted, into a DwarfDebug member. This is a preparatory
refactoring for allowing the GNU .debug_macro extension, which is a
precursor to the DWARF 5 format, to be emitted by LLVM for earlier DWARF
versions.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D82971
2020-08-11 13:30:52 +02:00
Igor Kudrin
a1f8fa9c5c [DebugInfo] Fix a comment and a variable name. NFC.
DebugLocListIndex keeps the index of an entry list, not the offset.

Differential Revision: https://reviews.llvm.org/D84093
2020-08-03 15:04:00 +07:00
David Blaikie
dc9888b6b6 DebugInfo: Move getMD5AsBytes from DwarfUnit to DwarfDebug
It wasn't using any state from DwarfUnit anyway.
2020-07-20 19:21:39 -07:00
zuojian lin
e43213dbb7 Fix undefined behavior in DWARF emission
Caused by uninitialized load of llvm::DwarfDebug::PrevCU:
llvm::DwarfCompileUnit::addRange () at ../lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:276
llvm::DwarfDebug::endFunctionImpl () at ../lib/CodeGen/AsmPrinter/DwarfDebug.cpp:1586
llvm::DebugHandlerBase::endFunction () at ../lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp:319
llvm::AsmPrinter::EmitFunctionBody () at ../lib/CodeGen/AsmPrinter/AsmPrinter.cpp:1230
llvm::ARMAsmPrinter::runOnMachineFunction () at ../lib/Target/ARM/ARMAsmPrinter.cpp:161

Most of the DebugInfo tests under `LLVM_LIT_ARGS:STRING=-sv --vg` prior to this fix, and pass with the fix applied.

Reviewed By: aprantl, dblaikie

Differential Revision: https://reviews.llvm.org/D81631
2020-07-13 18:32:36 -07:00
Jeremy Morse
5ea70edf9e [DWARF] Add cuttoff guarding quadratic validThroughout behaviour
Occasionally we see absolutely massive basic blocks, typically in global
constructors that are vulnerable to heavy inlining. When these blocks are
dense with DBG_VALUE instructions, we can hit near quadratic complexity in
DwarfDebug's validThroughout function. The problem is caused by:

  * validThroughout having to step through all instructions in the block to
    examine their lexical scope,
  * and a high proportion of instructions in that block being DBG_VALUEs
    for a unique variable fragment,

Leading to us stepping through every instruction in the block, for (nearly)
each instruction in the block.

By adding this guard, we force variables in large blocks to use a location
list rather than a single-location expression, as shown in the added test.
This shouldn't change the meaning of the output DWARF at all: instead we
use a less efficient DWARF encoding to avoid a poor-performance code path.

Differential Revision: https://reviews.llvm.org/D83236
2020-07-08 10:30:09 +01:00
Richard Smith
04069444bf Fix violations of [basic.class.scope]p2.
These cases all follow the same pattern:

struct A {
  friend class X;
  //...
  class X {};
};

But 'friend class X;' injects 'X' into the surrounding namespace scope,
rather than introducing a class member. So the second 'class X {}' is a
completely different type, which changes the meaning of the earlier name
'X' from '::X' to 'A::X'.

Additionally, the friend declaration is pointless -- members of a class
don't need to be befriended to be able to access private members.
2020-06-01 22:03:05 -07:00
Simon Pilgrim
115f590f26 DwarfDebug.h - remove unnecessary forward declarations. NFC.
We include their headers already.
2020-04-24 15:34:54 +01:00
Sourabh Singh Tomar
8ba532e8e1 [DWARF5] Added support for emission of debug_macro section.
Summary:
This patch adds support for emission of following DWARFv5 macro forms
in .debug_macro section.

1. DW_MACRO_start_file
2. DW_MACRO_end_file
3. DW_MACRO_define_strp
4. DW_MACRO_undef_strp.

Reviewed By: dblaikie, ikudrin

Differential Revision: https://reviews.llvm.org/D72828
2020-04-06 17:45:10 +05:30
Djordje Todorovic
39a83a112e Reland D73534: [DebugInfo] Enable the debug entry values feature by default
The issue that was causing the build failures was fixed with the D76164.
2020-03-19 13:57:30 +01:00
Nico Weber
55ba7badfd Revert "Reland "[DebugInfo] Enable the debug entry values feature by default""
This reverts commit 5aa5c943f7da155b95564058cd5d50a93eabfc89.
Causes clang to assert, see
https://bugs.chromium.org/p/chromium/issues/detail?id=1061533#c4
for a repro.
2020-03-13 15:37:44 -04:00
Djordje Todorovic
a4907284d9 Reland "[DebugInfo] Enable the debug entry values feature by default"
Differential Revision: https://reviews.llvm.org/D73534
2020-03-10 09:15:06 +01:00
Djordje Todorovic
e67d8322ba Revert "Reland "[DebugInfo] Enable the debug entry values feature by default""
This reverts commit rGfaff707db82d.
A failure found on an ARM 2-stage buildbot.
The investigation is needed.
2020-02-20 14:41:39 +01:00
Djordje Todorovic
fdc5995043 Reland "[DebugInfo] Enable the debug entry values feature by default"
Differential Revision: https://reviews.llvm.org/D73534
2020-02-19 11:12:26 +01:00
Djordje Todorovic
a8a9374ec7 Revert "Reland "[DebugInfo] Enable the debug entry values feature by default""
This reverts commit rGa82d3e8a6e67.
2020-02-18 16:38:11 +01:00
Djordje Todorovic
7e0c075702 Reland "[DebugInfo] Enable the debug entry values feature by default"
This patch enables the debug entry values feature.

  - Remove the (CC1) experimental -femit-debug-entry-values option
  - Enable it for x86, arm and aarch64 targets
  - Resolve the test failures
  - Leave the llc experimental option for targets that do not
    support the CallSiteInfo yet

Differential Revision: https://reviews.llvm.org/D73534
2020-02-18 14:41:08 +01:00
Djordje Todorovic
45581db685 Revert "[DebugInfo] Enable the debug entry values feature by default"
This reverts commit rG9f6ff07f8a39.

Found a test failure on clang-with-thin-lto-ubuntu buildbot.
2020-02-12 11:59:04 +01:00
Djordje Todorovic
69262470d0 [DebugInfo] Enable the debug entry values feature by default
This patch enables the debug entry values feature.

  - Remove the (CC1) experimental -femit-debug-entry-values option
  - Enable it for x86, arm and aarch64 targets
  - Resolve the test failures
  - Leave the llc experimental option for targets that do not
    support the CallSiteInfo yet

Differential Revision: https://reviews.llvm.org/D73534
2020-02-12 10:25:14 +01:00
Vedant Kumar
3ce517d29d Reland (again): [DWARF] Allow cross-CU references of subprogram definitions
This is a revert-of-revert (i.e. this reverts commit 802bec89, which
itself reverted fa4701e1 and 79daafc9) with a fix folded in. The problem
was that call site tags weren't emitted properly when LTO was enabled
along with split-dwarf. This required a minor fix. I've added a reduced
test case in test/DebugInfo/X86/fission-call-site.ll.

Original commit message:

This allows a call site tag in CU A to reference a callee DIE in CU B
without resorting to creating an incomplete duplicate DIE for the callee
inside of CU A.

We already allow cross-CU references of subprogram declarations, so it
doesn't seem like definitions ought to be special.

This improves entry value evaluation and tail call frame synthesis in
the LTO setting. During LTO, it's common for cross-module inlining to
produce a call in some CU A where the callee resides in a different CU,
and there is no declaration subprogram for the callee anywhere. In this
case llvm would (unnecessarily, I think) emit an empty DW_TAG_subprogram
in order to fill in the call site tag. That empty 'definition' defeats
entry value evaluation etc., because the debugger can't figure out what
it means.

As a follow-up, maybe we could add a DWARF verifier check that a
DW_TAG_subprogram at least has a DW_AT_name attribute.

Update #1:

Reland with a fix to create a declaration DIE when the declaration is
missing from the CU's retainedTypes list. The declaration is left out
of the retainedTypes list in two cases:

1) Re-compiling pre-r266445 bitcode (in which declarations weren't added
   to the retainedTypes list), and
2) Doing LTO function importing (which doesn't update the retainedTypes
   list).

It's possible to handle (1) and (2) by modifying the retainedTypes list
(in AutoUpgrade, or in the LTO importing logic resp.), but I don't see
an advantage to doing it this way, as it would cause more DWARF to be
emitted compared to creating the declaration DIEs lazily.

Update #2:

Fold in a fix for call site tag emission in the split-dwarf + LTO case.

Tested with a stage2 ThinLTO+RelWithDebInfo build of clang, and with a
ReleaseLTO-g build of the test suite.

rdar://46577651, rdar://57855316, rdar://57840415, rdar://58888440

Differential Revision: https://reviews.llvm.org/D70350
2020-01-27 10:52:34 -08:00
Vedant Kumar
0e3d6e2d5b Revert "Reland: [DWARF] Allow cross-CU references of subprogram definitions"
... as well as:
Revert "[DWARF] Defer creating declaration DIEs until we prepare call site info"

This reverts commit fa4701e1979553c2df61698ac1ac212627630442.

This reverts commit 79daafc90308787b52a5d3a7586e82acd5e374b3.

There have been reports of this assert getting hit:

CalleeDIE && "Could not find DIE for call site entry origin
2020-01-24 18:07:54 -08:00
David Blaikie
d1e21d6845 DebugInfo: Move SectionLabel tracking into CU's addRange
This makes the SectionLabel handling more resilient - specifically for
future PROPELLER work which will have more CU ranges (rather than just
one per function).

Ultimately it might be nice to make this more general/resilient to
arbitrary labels (rather than relying on the labels being created for CU
ranges & then being reused by ranges, loclists, and possibly other
addresses). It's possible that other (non-rnglist/loclist) uses of
addresses will need the addresses to be in SectionLabels earlier (eg:
move the CU.addRange to be done on function begin, rather than function
end, so during function emission they are already populated for other
use).
2020-01-17 18:12:34 -08:00
Vedant Kumar
a496d0518f Reland: [DWARF] Allow cross-CU references of subprogram definitions
This allows a call site tag in CU A to reference a callee DIE in CU B
without resorting to creating an incomplete duplicate DIE for the callee
inside of CU A.

We already allow cross-CU references of subprogram declarations, so it
doesn't seem like definitions ought to be special.

This improves entry value evaluation and tail call frame synthesis in
the LTO setting. During LTO, it's common for cross-module inlining to
produce a call in some CU A where the callee resides in a different CU,
and there is no declaration subprogram for the callee anywhere. In this
case llvm would (unnecessarily, I think) emit an empty DW_TAG_subprogram
in order to fill in the call site tag. That empty 'definition' defeats
entry value evaluation etc., because the debugger can't figure out what
it means.

As a follow-up, maybe we could add a DWARF verifier check that a
DW_TAG_subprogram at least has a DW_AT_name attribute.

Update:

Reland with a fix to create a declaration DIE when the declaration is
missing from the CU's retainedTypes list. The declaration is left out
of the retainedTypes list in two cases:

1) Re-compiling pre-r266445 bitcode (in which declarations weren't added
   to the retainedTypes list), and
2) Doing LTO function importing (which doesn't update the retainedTypes
   list).

It's possible to handle (1) and (2) by modifying the retainedTypes list
(in AutoUpgrade, or in the LTO importing logic resp.), but I don't see
an advantage to doing it this way, as it would cause more DWARF to be
emitted compared to creating the declaration DIEs lazily.

Tested with a stage2 ThinLTO+RelWithDebInfo build of clang, and with a
ReleaseLTO-g build of the test suite.

rdar://46577651, rdar://57855316, rdar://57840415

Differential Revision: https://reviews.llvm.org/D70350
2019-12-20 15:26:31 -08:00
Sourabh Singh Tomar
db77ea2438 Recommit "[DebugInfo] Refactored macro related generation,
added a test case for macinfo.dwo emission."

This was reverted in caa412090666c10f854322cdc701c1cbf8ed726e,
since it was causing an assertion failure on Windows bots.
This revision is revised to fix that.

Original commit message -

[DebugInfo] Refactored macro related generation, added a test case for macinfo.dwo emission.

Reviewers: dblaikie, aprantl, jini.susan.george

Tags: #debug-info #llvm

Differential Revision: https://reviews.llvm.org/D71008
2019-12-18 02:12:59 +05:30
David Blaikie
ee634363a8 NFC: DebugInfo: Refactor debug_loc/loclist emission into a common function
(except for v4 loclists, which are sufficiently different to not fit
well in this generic implementation)

In subsequent patches I intend to refactor the DebugLoc and ranges data
structures to be more similar so I can common more of the implementation
here.
2019-12-12 16:39:12 -08:00
Evgenii Stepanov
1b96f8703a hwasan: add tag_offset DWARF attribute to optimized debug info
Summary:
Support alloca-referencing dbg.value in hwasan instrumentation.
Update AsmPrinter to emit DW_AT_LLVM_tag_offset when location is in
loclist format.

Reviewers: pcc

Subscribers: srhines, aprantl, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70753
2019-12-12 16:18:54 -08:00
Vedant Kumar
0c775a21ee Revert "[DWARF] Allow cross-CU references of subprogram definitions"
This reverts commit 30038da15b18ac4e34b9ea7a648382ae481e4770. It causes
the stage2 thinLTO bot to fail with:

Assertion failed: (CU.getDIE(CalleeSP) && "Expected declaration subprogram DIE for callee")

rdar://57840415
2019-12-11 15:55:48 -08:00
Nico Weber
539c3f0528 Revert "[DebugInfo] Refactored macro related generation, added a test case for macinfo.dwo emission."
This reverts commit 307f60a1a3ff04313a75e2fc11bc14df4fc2ffb8.

DebugInfo/X86/debug-macinfo-split-dwarf.ll fails on Windows:

Command Output (stdout):
--
$ ":" "RUN: at line 1"
$ "c:\src\llvm-project\out\gn\bin\llc.exe" "-mtriple=x86_64-pc-windows-gnu" "-O0" "-split-dwarf-file=foo.dwo" "-filetype=obj"
Assertion failed: Section && "Cannot switch to a null section!", file ../../llvm/lib/MC/MCStreamer.cpp, line 1103
Stack dump:
0.	Program arguments: c:\src\llvm-project\out\gn\bin\llc.exe -mtriple=x86_64-pc-windows-gnu -O0 -split-dwarf-file=foo.dwo -filetype=obj
2019-12-10 21:32:30 -05:00
Vedant Kumar
83067278fa [DWARF] Allow cross-CU references of subprogram definitions
This allows a call site tag in CU A to reference a callee DIE in CU B
without resorting to creating an incomplete duplicate DIE for the callee
inside of CU A.

We already allow cross-CU references of subprogram declarations, so it
doesn't seem like definitions ought to be special.

This improves entry value evaluation and tail call frame synthesis in
the LTO setting. During LTO, it's common for cross-module inlining to
produce a call in some CU A where the callee resides in a different CU,
and there is no declaration subprogram for the callee anywhere. In this
case llvm would (unnecessarily, I think) emit an empty DW_TAG_subprogram
in order to fill in the call site tag. That empty 'definition' defeats
entry value evaluation etc., because the debugger can't figure out what
it means.

As a follow-up, maybe we could add a DWARF verifier check that a
DW_TAG_subprogram at least has a DW_AT_name attribute.

rdar://46577651

Differential Revision: https://reviews.llvm.org/D70350
2019-12-10 14:00:57 -08:00