Commit Graph

2704 Commits

Author SHA1 Message Date
Nilanjana Basu ac7e5788ca Changes to improve CodeView debug info type record inline comments
Signed-off-by: Nilanjana Basu <nilanjana.basu87@gmail.com>
llvm-svn: 367623
2019-08-01 22:05:14 +00:00
Djordje Todorovic b9973f87c6 Reland "[DwarfDebug] Dump call site debug info"
The build failure found after the rL365467 has been
resolved.

Differential Revision: https://reviews.llvm.org/D60716

llvm-svn: 367446
2019-07-31 16:51:28 +00:00
Nilanjana Basu 06b8fe8d03 Changes to emit CodeView debug info nested type records properly using MCStreamer directives
llvm-svn: 366720
2019-07-22 18:22:55 +00:00
Hsiangkai Wang c5ecdd3c5a [DebugInfo] Some fields do not need relocations even relax is enabled.
In debug frame information, some fields, e.g., Length in CIE/FDE and
Offset in FDE are attributes to describe the structure of CIE/FDE. They
are not related to the relaxed code. However, these attributes are
symbol differences. So, in current design, these attributes will be
filled as zero and LLVM generates relocations for them.

We only need to generate relocations for symbols in executable sections.
So, if the symbols are not located in executable sections, we still
evaluate their values under relaxation.

Differential Revision: https://reviews.llvm.org/D61584

llvm-svn: 366531
2019-07-19 06:10:36 +00:00
Hsiangkai Wang 18ccfadd46 [DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.

There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.

Differential Revision: https://reviews.llvm.org/D58335

llvm-svn: 366524
2019-07-19 02:03:34 +00:00
Hsiangkai Wang 657277e0f1 Revert "[DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame."
This reverts commit 17e3cbf5fe656483d9016d0ba9e1d0cd8629379e.

llvm-svn: 366444
2019-07-18 15:06:50 +00:00
Hsiangkai Wang e43ce1a958 [DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.

There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.

Differential Revision: https://reviews.llvm.org/D58335

llvm-svn: 366442
2019-07-18 14:47:34 +00:00
Alex Bradbury dad1bebecd [RISCV][DebugInfo] Fix dwarf-riscv-relocs.ll test on Windows
Windows sees DW_AT_decl_file (".\dwarf-riscv-relocs.c") while Linux sees
DW_AT_decl_file ("./dwarf-riscv-relocs.c").

This fixes a failure introduced in rL366402.

llvm-svn: 366410
2019-07-18 07:25:56 +00:00
Alex Bradbury 44deaf7e54 [DWARF][RISCV] Add support for RISC-V relocations needed for debug info
When code relaxation is enabled many RISC-V fixups are not resolved but
instead relocations are emitted. This happens even for DWARF debug
sections. Therefore, to properly support the parsing of DWARF debug info
we need to be able to resolve RISC-V relocations. This patch adds:

* Support for RISC-V relocations in RelocationResolver
* DWARF support for two relocations per object file offset
* DWARF changes to support relocations in more DIE fields

The two relocations per offset change is needed because some RISC-V
relocations (used for label differences) come in pairs.

Relocations can also be emitted for DWARF fields where relocations were
not yet evaluated. Adding relocation support for some of these fields is
essencial. On the other hand, LLVM currently emits RISC-V relocations
for fixups that could be safely evaluated, since they can never be
affected by code relaxations. This patch also adds relocation support
for the fields affected by those extraneous relocations (the DWARF unit
entry Length, and the DWARF debug line entry TotalLength and
PrologueLength), for testing purposes.

Differential Revision: https://reviews.llvm.org/D62062
Patch by Luís Marques.

llvm-svn: 366402
2019-07-18 05:22:55 +00:00
Nilanjana Basu 4e22770219 Changes to display code view debug info type records in hex format
llvm-svn: 366390
2019-07-17 23:43:58 +00:00
Nilanjana Basu 6e4076699c Adding inline comments to code view type record directives for better readability
llvm-svn: 366372
2019-07-17 21:01:12 +00:00
Alex Bradbury aa55124eca [RISCV][NFC] Add tests that capture current encodings for DWARF EH
Items which are known to be wrong/different vs GCC are marked as TODO and will
be address in follow-up patches.

llvm-svn: 366326
2019-07-17 13:48:49 +00:00
David Blaikie 40580d36c4 DWARF: Skip zero column for inline call sites
D64033 <https://reviews.llvm.org/D64033> added DW_AT_call_column for
inline sites. However, that change wasn't aware of "-gno-column-info".
To avoid adding column info when "-gno-column-info" is used, now
DW_AT_call_column is only added when we have non-zero column (when
"-gno-column-info" is used, column will be zero).

Patch by Wenlei He!

Differential Revision: https://reviews.llvm.org/D64784

llvm-svn: 366264
2019-07-16 21:15:19 +00:00
Jonas Devlieghere 83264b3580 [DebugInfo] Add column info for inline sites
The column field is missing for all inline sites, currently it's always
zero. This changes populates DW_AT_call_column field for inline sites.
Test case modified to cover this change.

Patch by: Wenlei He

Differential revision: https://reviews.llvm.org/D64033

llvm-svn: 365945
2019-07-12 19:25:45 +00:00
Djordje Todorovic 0739ccd3b5 Revert "[DwarfDebug] Dump call site debug info"
A build failure was found on the SystemZ platform.

This reverts commit 9e7e73578e54cd22b3c7af4b54274d743b6607cc.

llvm-svn: 365886
2019-07-12 09:45:12 +00:00
Nico Weber ce84e6ae8e Make pdbdump-objfilename test work again
- The test had extension .yaml, which lit doesn't execute in this
  directory. Rename to .test to make it run, and move the yaml bits
  into a dedicated file, like with all other tests in this dir.

- llvm-pdbdump got renamed to llvm-pdbutil long ago, update test.

- -dbi-module-info got renamed in r305032, update test for this too.

llvm-svn: 365514
2019-07-09 17:02:51 +00:00
Djordje Todorovic 01eaae6dd1 [DwarfDebug] Dump call site debug info
Dump the DWARF information about call sites and call site parameters into
debug info sections.

The patch also provides an interface for the interpretation of instructions
that could load values of a call site parameters in order to generate DWARF
about the call site parameters.

([13/13] Introduce the debug entry values.)

Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>

Differential Revision: https://reviews.llvm.org/D60716

llvm-svn: 365467
2019-07-09 11:33:56 +00:00
Jeremy Morse 9bebc65d79 Revert r364515 and r364524
Jordan reports on llvm-commits a performance regression with r364515,
backing the patch out while it's investigated.

llvm-svn: 365448
2019-07-09 09:38:03 +00:00
Djordje Todorovic 12aca5de02 Reland "[LiveDebugValues] Emit the debug entry values"
Emit replacements for clobbered parameters location if the parameter
has unmodified value throughout the funciton. This is basic scenario
where we can use the debug entry values.

([12/13] Introduce the debug entry values.)

Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>

Differential Revision: https://reviews.llvm.org/D58042

llvm-svn: 365444
2019-07-09 08:36:34 +00:00
Nilanjana Basu faed8516e4 Changing CodeView debug info type record representation in assembly files to make it more human-readable & editable & fixing bug introduced in r364987
llvm-svn: 365417
2019-07-09 01:11:02 +00:00
Nilanjana Basu c0b557744a Revert Changing CodeView debug info type record representation in assembly files to make it more human-readable & editable
This reverts r364982 (git commit 2082bf28eb)

llvm-svn: 364987
2019-07-03 00:51:49 +00:00
Nilanjana Basu 2082bf28eb Changing CodeView debug info type record representation in assembly files to make it more human-readable & editable
llvm-svn: 364982
2019-07-03 00:26:23 +00:00
Paul Robinson a5f3e278c8 Use --defsym instead of sed in a test. NFC
llvm-svn: 364929
2019-07-02 14:47:49 +00:00
Jeremy Morse d2b6665e33 [DebugInfo] Avoid adding too much indirection to pointer-valued variables
This patch addresses PR41675, where a stack-pointer variable is dereferenced
too many times by its location expression, presenting a value on the stack as
the pointer to the stack.

The difference between a stack *pointer* DBG_VALUE and one that refers to a
value on the stack, is currently the indirect flag. However the DWARF backend
will also try to guess whether something is a memory location or not, based
on whether there is any computation in the location expression. By simply
prepending the stack offset to existing expressions, we can accidentally
convert a register location into a memory location, which introduces a
suprise (and unintended) dereference.

The solution is to add DW_OP_stack_value whenever we add a DIExpression
computation to a stack *pointer*. It's an implicit location computed on the
expression stack, thus needs to be flagged as a stack_value.

For the edge case where the offset is zero and the location could be a register
location, DIExpression::prepend will still generate opcodes, and thus
DW_OP_stack_value must still be added.

Differential Revision: https://reviews.llvm.org/D63429

llvm-svn: 364736
2019-07-01 09:38:23 +00:00
Djordje Todorovic 774eabd097 Revert "[LiveDebugValues] Emit the debug entry values"
Appears that the 'test/DebugInfo/MIR/X86/dbginfo-entryvals.mir'
does not pass on Windows.

This reverts commit rL364553.

llvm-svn: 364571
2019-06-27 18:12:04 +00:00
Djordje Todorovic d6a46aff59 [LiveDebugValues] Emit the debug entry values
Emit replacements for clobbered parameters location if the parameter
has unmodified value throughout the funciton. This is basic scenario
where we can use the debug entry values.

([12/13] Introduce the debug entry values.)

Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>

Differential Revision: https://reviews.llvm.org/D58042

llvm-svn: 364553
2019-06-27 15:35:48 +00:00
Jeremy Morse 3ca8f2b007 Add triple to a test I just added.
llvm-svn: 364524
2019-06-27 11:52:03 +00:00
Jeremy Morse d528bcd965 [DebugInfo] Avoid register coalesing unsoundly changing DBG_VALUE locations
Once MIR code leaves SSA form and the liveness of a vreg is considered,
DBG_VALUE insts are able to refer to non-live vregs, because their
debug-uses do not contribute to liveness. This non-liveness becomes
problematic for optimizations like register coalescing, as they can't
``see'' the debug uses in the liveness analyses.

As a result registers get coalesced regardless of debug uses, and that can
lead to invalid variable locations containing unexpected values. In the
added test case, the first vreg operand of ADD32rr is merged with various
copies of the vreg (great for performance), but a DBG_VALUE of the
unmodified operand is blindly updated to the modified operand. This changes
what value the variable will appear to have in a debugger.

Fix this by changing any DBG_VALUE whose operand will be resurrected by
register coalescing to be a $noreg DBG_VALUE, i.e. give the variable no
location. This is an overapproximation as some coalesced locations are
safe (others are not) -- an extra domination analysis would be required to
work out which, and it would be better if we just don't generate non-live
DBG_VALUEs.

This fixes PR40010.

Differential Revision: https://reviews.llvm.org/D56151

llvm-svn: 364515
2019-06-27 10:20:27 +00:00
Thomas Lively a1d97a960e [WebAssembly] Implement tail calls and unify tablegen call classes
Summary:
Implements direct and indirect tail calls enabled by the 'tail-call'
feature in both DAG ISel and FastISel. Updates existing call tests and
adds new tests including a binary encoding test.

Reviewers: aheejin

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62877

llvm-svn: 364445
2019-06-26 16:17:15 +00:00
Amy Huang 7fac5c8d94 Store a pointer to the return value in a static alloca and let the debugger use that
as the variable address for NRVO variables.

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D63361

llvm-svn: 363952
2019-06-20 17:15:21 +00:00
Fangrui Song 102b1efd53 [llvm-dwarfdump] --gdb-index: fix uninitialized TuListOffset
The test only checks the existence of the `Types CU list` line.
Unfortunately I can't make a better test because
{gcc,clang} -fuse-ld={lld,gold} --gdb-index do not give me a non-empty types CU list.

Reviewed By: ikudrin

Differential Revision: https://reviews.llvm.org/D63537

llvm-svn: 363800
2019-06-19 13:51:29 +00:00
Orlando Cazalet-Hyams 1251cac62a [DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion
Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

> llvm-svn: 363046

llvm-svn: 363786
2019-06-19 10:50:47 +00:00
Matt Arsenault 9cac4e6d14 Rename ExpandISelPseudo->FinalizeISel, delay register reservation
This allows targets to make more decisions about reserved registers
after isel. For example, now it should be certain there are calls or
stack objects in the frame or not, which could have been introduced by
legalization.

Patch by Matthias Braun

llvm-svn: 363757
2019-06-19 00:25:39 +00:00
Fangrui Song ac14f7b10c [lit] Delete empty lines at the end of lit.local.cfg NFC
llvm-svn: 363538
2019-06-17 09:51:07 +00:00
Sander de Smalen 5d6ee76c16 Describe stack-id as an enum
This patch changes MIR stack-id from an integer to an enum,
and adds printing/parsing support for this in MIR files. The default
stack-id '0' is now renamed to 'default'.

This should make MIR tests that have stack objects with different stack-ids
more descriptive. It also clarifies code operating on StackID.

Reviewers: arsenm, thegameg, qcolombet

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D60137

llvm-svn: 363533
2019-06-17 09:13:29 +00:00
Guozhi Wei d2210af332 [MBP] Move a latch block with conditional exit and multi predecessors to top of loop
Current findBestLoopTop can find and move one kind of block to top, a latch block has one successor. Another common case is:

    * a latch block
    * it has two successors, one is loop header, another is exit
    * it has more than one predecessors

If it is below one of its predecessors P, only P can fall through to it, all other predecessors need a jump to it, and another conditional jump to loop header. If it is moved before loop header, all its predecessors jump to it, then fall through to loop header. So all its predecessors except P can reduce one taken branch.

Differential Revision: https://reviews.llvm.org/D43256

llvm-svn: 363471
2019-06-14 23:08:59 +00:00
David Blaikie 4129e3e0f8 DebugInfo: Include enumerators in pubnames
This is consistent with GCC's behavior (which is the defacto standard
for pubnames). Though I find the presence of enumerators from enum
classes to be a bit confusing, possibly a bug on GCC's end (since they
can't be named unqualified, unlike the other names - and names nested in
classes don't go in pubnames, for instance - presumably because one must
name the class first & that's enough to limit the scope of the search)

llvm-svn: 363349
2019-06-14 01:58:56 +00:00
Tim Shen 4121bdc3d4 [X86] Add target triple for live-debug-values-fragments.mir
llvm-svn: 363348
2019-06-14 01:41:04 +00:00
Amy Huang 49275272e3 Use fully qualified name when printing S_CONSTANT records
Summary:
Before it was using the fully qualified name only for static data members.
Now it does for all variable names to match MSVC.

Reviewers: rnk

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63012

llvm-svn: 363335
2019-06-13 22:53:43 +00:00
Amara Emerson fb0a40f064 [GlobalISel][IRTranslator] Add debug loc with line 0 to constants emitted into the entry block.
Constants, including G_GLOBAL_VALUE, are all emitted into the entry block which
lets us use the vreg def assuming it dominates all other users. However, it can
cause jumpy debug behaviour since the DebugLoc attached to these MIs are from
a user instruction that could be in a different block.

Fixes PR40887.

Differential Revision: https://reviews.llvm.org/D63286

llvm-svn: 363331
2019-06-13 22:15:35 +00:00
Jeremy Morse bf2b2f08b0 [DebugInfo] Honour variable fragments in LiveDebugValues
This patch makes the LiveDebugValues pass consider fragments when propagating
DBG_VALUE insts between blocks, fixing PR41979. Fragment info for a variable
location is added to the open-ranges key, which allows distinct fragments to be
tracked separately. To handle overlapping fragments things become slightly
funkier. To avoid excessive searching for overlaps in the data-flow part of
LiveDebugValues, this patch:
 * Pre-computes pairings of fragments that overlap, for each DILocalVariable
 * During data-flow, whenever something happens that causes an open range to
   be terminated (via erase), any fragments pre-determined to overlap are
   also terminated.

The effect of which is that when encountering a DBG_VALUE fragment that
overlaps others, the overlapped fragments do not get propagated to other
blocks. We still rely on later location-list building to correctly handle
overlapping fragments within blocks.

It's unclear whether a mixture of DBG_VALUEs with and without fragmented
expressions are legitimate. To avoid suprises, this patch interprets a
DBG_VALUE with no fragment as overlapping any DBG_VALUE _with_ a fragment.

Differential Revision: https://reviews.llvm.org/D62904

llvm-svn: 363256
2019-06-13 12:51:57 +00:00
Jeremy Morse 181bf0cefb [DebugInfo] Use FrameDestroy to extend stack locations to end-of-function
We aim to ignore changes in variable locations during the prologue and
epilogue of functions, to avoid using space documenting location changes
that aren't visible. However in D61940 / r362951 this got ripped out as
the previous implementation was unsound.

Instead, use the FrameDestroy flag to identify when we're in the epilogue
of a function, and ignore variable location changes accordingly. This fits
in with existing code that examines the FrameSetup flag.

Some variable locations get shuffled in modified tests as they now cover
greater ranges, which is what would be expected. Some additional
single-location variables are generated too. Two tests are un-xfailed,
they were only xfailed due to r362951 deleting functionality they depended
on.

Apparently some out-of-tree backends don't accurately maintain FrameDestroy
flags -- if you're an out-of-tree maintainer and see changes in variable
locations disappear due to a faulty FrameDestroy flag, it's safe to back
this change out. The impact is just slightly more debug info than necessary.

Differential Revision: https://reviews.llvm.org/D62314

llvm-svn: 363245
2019-06-13 10:03:17 +00:00
Jeremy Morse e2f94974df [DebugInfo] Add a test that fell out of an earlier commit
r362951 was supposed to contain this test, however it didn't get committed
due to operator error. This was originally part of D59431.

llvm-svn: 363161
2019-06-12 13:41:56 +00:00
Orlando Cazalet-Hyams a947156396 Revert "[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion"
This reverts commit 1a0f7a2077.
See phabricator thread for D60831.

llvm-svn: 363132
2019-06-12 08:34:51 +00:00
Orlando Cazalet-Hyams 1a0f7a2077 [DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion
Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

llvm-svn: 363046
2019-06-11 10:37:20 +00:00
Francis Visoiu Mistrih a438432acc [FastISel] Skip creating unnecessary vregs for arguments
This behavior was added in r130928 for both FastISel and SD, and then
disabled in r131156 for FastISel.

This re-enables it for FastISel with the corresponding fix.

This is triggered only when FastISel can't lower the arguments and falls
back to SelectionDAG for it.

FastISel contains a map of "register fixups" where at the end of the
selection phase it replaces all uses of a register with another
register that FastISel sometimes pre-assigned. Code at the end of
SelectionDAGISel::runOnMachineFunction is doing the replacement at the
very end of the function, while other pieces that come in before that
look through the MachineFunction and assume everything is done. In this
case, the real issue is that the code emitting COPY instructions for the
liveins (physreg to vreg) (EmitLiveInCopies) is checking if the vreg
assigned to the physreg is used, and if it's not, it will skip the COPY.
If a register wasn't replaced with its assigned fixup yet, the copy will
be skipped and we'll end up with uses of undefined registers.

This fix moves the replacement of registers before the emission of
copies for the live-ins.

The initial motivation for this fix is to enable tail calls for
swiftself functions, which were blocked because we couldn't prove that
the swiftself argument (which is callee-save) comes from a function
argument (live-in), because there was an extra copy (vreg to vreg).

A few tests are affected by this:

* llvm/test/CodeGen/AArch64/swifterror.ll: we used to spill x21
(callee-save) but never reload it because it's attached to the return.
We now don't even spill it anymore.
* llvm/test/CodeGen/*/swiftself.ll: we tail-call now.
* llvm/test/CodeGen/AMDGPU/mubuf-legalize-operands.ll: I believe this
test was not really testing the right thing, but it worked because the
same registers were re-used.
* llvm/test/CodeGen/ARM/cmpxchg-O0.ll: regalloc changes
* llvm/test/CodeGen/ARM/swifterror.ll: get rid of a copy
* llvm/test/CodeGen/Mips/*: get rid of spills and copies
* llvm/test/CodeGen/SystemZ/swift-return.ll: smaller stack
* llvm/test/CodeGen/X86/atomic-unordered.ll: smaller stack
* llvm/test/CodeGen/X86/swifterror.ll: same as AArch64
* llvm/test/DebugInfo/X86/dbg-declare-arg.ll: stack size changed

Differential Revision: https://reviews.llvm.org/D62361

llvm-svn: 362963
2019-06-10 16:53:37 +00:00
Jeremy Morse bcff417292 [DebugInfo] Terminate all location-lists at end of block
This commit reapplies r359426 (which was reverted in r360301 due to
performance problems) and rolls in D61940 to address the performance problem.
I've combined the two to avoid creating a span of slow-performance, and to
ease reverting if more problems crop up.

The summary of D61940: This patch removes the "ChangingRegs" facility in
DbgEntityHistoryCalculator, as its overapproximate nature can produce incorrect
variable locations. An unchanging register doesn't mean a variable doesn't
change its location.

The patch kills off everything that calculates the ChangingRegs vector.
Previously ChangingRegs spotted epilogues and marked registers as unchanging if
they weren't modified outside the epilogue, increasing the chance that we can
emit a single-location variable record. Without this feature,
debug-loc-offset.mir and pr19307.mir become temporarily XFAIL. They'll be
re-enabled by D62314, using the FrameDestroy flag to identify epilogues, I've
split this into two steps as FrameDestroy isn't necessarily supported by all
backends.

The logic for terminating variable locations at the end of a basic block now
becomes much more enjoyably simple: we just terminate them all.

Other test changes: inlined-argument.ll becomes XFAIL, but for a longer term.
The current algorithm for detecting that a variable has a single-location
doesn't work in this scenario (inlined function in multiple blocks), only other
bugs were making this test work. fission-ranges.ll gets slightly refreshed too,
as the location of "p" is now correctly determined to be a single location.

Differential Revision: https://reviews.llvm.org/D61940

llvm-svn: 362951
2019-06-10 15:23:46 +00:00
Nikola Prica abc1dff7e4 [DebugInfo] More strict debug range for stack variables
Variable's stack location can stretch longer than it should. If a
variable is placed at the stack in a some nested basic block its range
can be calculated to be up to the next occurrence of the variable's
DBG_VALUE, or up to the end of the function, thus covering a basic
blocks that should not be included in the variable’s location range.
This happens because the DbgEntityHistoryCalculator ends register
locations at the end of a basic block only if the variable’s location
register has been changed throughout the function, which is not the
case for the register used to reference stack objects.

This patch also tries to produce a single value location if the location
list builder managed to merge all the locations into one.

Reviewers: aprantl, dstenb, jmorse

Reviewed By: aprantl, dstenb, jmorse

Subscribers: djtodoro, ivanbaev, asowda

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D61600

llvm-svn: 362923
2019-06-10 08:41:06 +00:00
Alexey Lapshin b9f1e7b16e [DebugInfo] Incorrect debug info record generated for loop counter.
Incorrect Debug Variable Range was calculated while "COMPUTING LIVE DEBUG VARIABLES" stage.
Range for Debug Variable("i") computed according to current state of instructions
inside of basic block. But Register Allocator creates new instructions which were not taken
into account when Live Debug Variables computed. In the result DBG_VALUE instruction for
the "i" variable was put after these newly inserted instructions. This is incorrect.
Debug Value for the loop counter should be inserted before any loop instruction.

Differential Revision: https://reviews.llvm.org/D62650

llvm-svn: 362750
2019-06-06 21:19:39 +00:00
Nikola Prica 2d0106a110 [LiveDebugValues] Close range for previous variable's location when adding newly deduced location
When LiveDebugValues deduces new variable's location from spill, restore or
register copy instruction it should close old variable's location. Otherwise
we can have multiple block output locations for same variable. That could lead
to inserting two DBG_VALUEs for same variable to the beginning of the successor
block which results to ignoring of first DBG_VALUE.

Reviewers: aprantl, jmorse, wolfgangp, dstenb

Reviewed By: aprantl

Subscribers: probinson, asowda, ivanbaev, petarj, djtodoro

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D62196

llvm-svn: 362373
2019-06-03 09:48:29 +00:00
Tom Tan 2258ecc2aa [COFF, ARM64] Fix location of ARM64 CodeView test
ARM64 CodeView test was incorrectly put under test/DebugInfo/COFF folder which
runs for all all architectures. This fix moves it to a subfolder AArch64 with
lit.local.cfg which specify it supports AArch64 only.

llvm-svn: 362283
2019-06-01 02:38:08 +00:00
Tom Tan eb4d6142dc [COFF, ARM64] Add CodeView register mapping
CodeView has its own register map which is defined in cvconst.h. Missing this
mapping before saving register to CodeView causes debugger to show incorrect
value for all register based variables, like variables in register and local
variables addressed by register (stack pointer + offset).

This change added mapping between LLVM register and CodeView register so the
correct register number will be stored to CodeView/PDB, it aso fixed the
mapping from CodeView register number to register name based on current
CPUType but print PDB to yaml still assumes X86 CPU and needs to be fixed.

Differential Revision: https://reviews.llvm.org/D62608

llvm-svn: 362280
2019-05-31 23:43:31 +00:00
Amy Huang dd3a9caf47 Add enums as global variables in the IR metadata.
Summary:
Keeps track of the enums that were used by saving them as DIGlobalVariables,
since CodeView emits debug info for global constants.

Reviewers: rnk

Subscribers: aprantl, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D62635

llvm-svn: 362166
2019-05-30 22:04:11 +00:00
Amy Huang 325003be02 CodeView - add static data members to global variable debug info.
Summary:
Add static data members to IR debug info's list of global variables
so that they are emitted as S_CONSTANT records.

Related to https://bugs.llvm.org/show_bug.cgi?id=41615.

Reviewers: rnk

Subscribers: aprantl, cfe-commits, llvm-commits, thakis

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D62167

llvm-svn: 362038
2019-05-29 21:45:34 +00:00
David Stenberg 5d0e6b6755 Stop undef fragments from closing non-overlapping fragments
Summary:
When DwarfDebug::buildLocationList() encountered an undef debug value,
it would truncate all open values, regardless if they were overlapping or
not. This patch fixes so that it only does that for overlapping fragments.

This change unearthed a bug that I had introduced in D57511,
which I have fixed in this patch. The code in DebugHandlerBase that
changes labels for parameter debug values could break DwarfDebug's
assumption that the labels for the entries in the debug value history
are monotonically increasing. Before this patch, that bug could result
in location list entries whose ending address was lower than the
beginning address, and with the changes for undef debug values that this
patch introduces it could trigger an assertion, due to attempting to
emit location list entries with empty ranges. A reproducer for the bug
is added in param-reg-const-mix.mir.

Reviewers: aprantl, jmorse, probinson

Reviewed By: aprantl

Subscribers: javed.absar, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D62379

llvm-svn: 361820
2019-05-28 13:23:25 +00:00
David Blaikie a17564c2f1 llvm-dwarfdump: Don't error on mixed units using/not using str_offsets
This lead to errors when dumping binaries with v4 and v5 units linked
together (but could've also errored on v5 units that did/didn't use
str_offsets).

Also improves error handling and messages around invalid str_offsets
contributions.

llvm-svn: 361683
2019-05-25 00:07:22 +00:00
David Blaikie fc302c2b7f dwarfdump: Deterministically... determine whether parsing a DWARF32 or DWARF64 str_offsets header
Rather than trying one and then the other - use the kind of the CU to
select which kind of header to parse.

llvm-svn: 361589
2019-05-24 01:41:58 +00:00
David Blaikie 79872a88a0 dwarfdump: Add a bit more DWARF64 support
This test case was incorrect because it mixed DWARF32 and DWARF64 for a
single unit (DWARF32 unit referencing a DWARF64 str_offsets section). So
fix enough of the unit parsing for DWARF64 and make the test valid.

(not sure if anyone needs DWARF64 support though - support in
libDebugInfoDWARF has been added piecemeal and LLVM doesn't produce it
at all)

llvm-svn: 361582
2019-05-24 01:05:52 +00:00
Paul Robinson 0a16ba856b [DebugInfo] Fix tests missed by r362148
llvm-svn: 361251
2019-05-21 12:48:46 +00:00
Bob Haarman 032f87bbb3 Revert r360902 "Resubmit: [Salvage] Change salvage debug info ..."
This reverts commit rr360902. It caused an assertion failure in
lib/IR/DebugInfoMetadata.cpp: Assertion `(OffsetInBits + SizeInBits <=
FragmentSizeInBits) && "new fragment outside of original fragment"'
failed.

PR41931.

llvm-svn: 361246
2019-05-21 11:53:41 +00:00
Paul Robinson 116e8d4876 [DebugInfo] Handle -main-file-name correctly for asm source.
This option provides only the base filename, not a full relative path.

Part of the fix for PR41839.

Differential Revision: https://reviews.llvm.org/D62071

llvm-svn: 361245
2019-05-21 11:52:27 +00:00
Amy Huang c2029068bc Emit global variables as S_CONSTANT records for codeview debug info.
Summary:
This emits S_CONSTANT records for global variables.
Currently this emits records for the global variables already being tracked in the
LLVM IR metadata, which are just constant global variables; we'll also want S_CONSTANTs
for static data members and enums.

Related to https://bugs.llvm.org/show_bug.cgi?id=41615

Reviewers: rnk

Subscribers: aprantl, hiraditya, llvm-commits, thakis

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61926

llvm-svn: 360948
2019-05-16 22:28:52 +00:00
Stephen Tozer 6f59b4b6d9 Resubmit: [Salvage] Change salvage debug info implementation to use DW_OP_LLVM_convert where needed
Fixes issue: https://bugs.llvm.org/show_bug.cgi?id=40645

Previously, LLVM had no functional way of performing casts inside of a
DIExpression(), which made salvaging cast instructions other than Noop casts
impossible. With the recent addition of DW_OP_LLVM_convert this salvaging is
now possible, and so can be used to fix the attached bug as well as any cases
where SExt instruction results are lost in the debugging metadata. This patch
introduces this fix by expanding the salvage debug info method to cover these
cases using the new operator.

Differential revision: https://reviews.llvm.org/D61184

llvm-svn: 360902
2019-05-16 14:41:01 +00:00
Matt Arsenault 828b685ebe RegAllocFast: Improve hinting heuristic
Trace through multiple COPYs when looking for a physreg source. Add
hinting for vregs that will be copied into physregs (we only hinted
for vregs getting copied to a physreg previously).  Give hinted a
register a bonus when deciding which value to spill.  This is part of
my rewrite regallocfast series. In fact this one doesn't even have an
effect unless you also flip the allocation to happen from back to
front of a basic block. Nonetheless it helps to split this up to ease
review of D52010

Patch by Matthias Braun

llvm-svn: 360887
2019-05-16 12:50:39 +00:00
Reid Kleckner 7c438c5b07 [codeview] Finish support for reading and writing S_ANNOTATION records
Implement dumping via llvm-pdbutil and llvm-readobj.

llvm-svn: 360813
2019-05-15 20:53:39 +00:00
Stephen Tozer 0d02f2ff4f Revert "[Salvage] Change salvage debug info implementation to use DW_OP_LLVM_convert where needed"
This reverts r360772 due to build issues.
Reverted commit: 17dd4d7403.

llvm-svn: 360773
2019-05-15 13:41:44 +00:00
Stephen Tozer 17dd4d7403 [Salvage] Change salvage debug info implementation to use DW_OP_LLVM_convert where needed
Fixes issue: https://bugs.llvm.org/show_bug.cgi?id=40645

Previously, LLVM had no functional way of performing casts inside of a
DIExpression(), which made salvaging cast instructions other than Noop
casts impossible. With the recent addition of DW_OP_LLVM_convert this
salvaging is now possible, and so can be used to fix the attached bug as
well as any cases where SExt instruction results are lost in the
debugging metadata. This patch introduces this fix by expanding the
salvage debug info method to cover these cases using the new operator.

Differential revision: https://reviews.llvm.org/D61184

llvm-svn: 360772
2019-05-15 13:15:48 +00:00
Fangrui Song f4dfd63c74 [IR] Disallow llvm.global_ctors and llvm.global_dtors of the 2-field form in textual format
The 3-field form was introduced by D3499 in 2014 and the legacy 2-field
form was planned to be removed in LLVM 4.0

For the textual format, this patch migrates the existing 2-field form to
use the 3-field form and deletes the compatibility code.
test/Verifier/global-ctors-2.ll checks we have a friendly error message.

For bitcode, lib/IR/AutoUpgrade UpgradeGlobalVariables will upgrade the
2-field form (add i8* null as the third field).

Reviewed By: rnk, dexonsmith

Differential Revision: https://reviews.llvm.org/D61547

llvm-svn: 360742
2019-05-15 02:35:32 +00:00
Fangrui Song 2f6ef2fc92 DWARF v5: emit DW_AT_addr_base if DW_AT_low_pc references .debug_addr
The condition !AddrPool.empty() is tested before attachRangesOrLowHighPC(), which may add an entry to AddrPool. We emit DW_AT_low_pc (DW_FORM_addrx) but may incorrectly omit DW_AT_addr_base for LineTablesOnly. This can be easily reproduced:

clang -gdwarf-5 -gmlt -c a.cc

Fix this by moving !AddrPool.empty() below.

This was discovered while investigating an lld crash (fixed by D61889) on such object files: ld.lld --gdb-index a.o

Reviewed By: probinson

Differential Revision: https://reviews.llvm.org/D61891

llvm-svn: 360678
2019-05-14 14:37:26 +00:00
David Blaikie 7598b71488 DebugInfo: Only move types out of type units if they're named or type united
Follow up to r359122, after a bug was reported in it - the original
change too aggressively tried to move related types out of type units,
which included unnamed types (like array types) which can't reasonably
be declared-but-not-defined.

A step beyond that is that some types in type units can be anonymous, if
they are types with a name for linkage purposes (eg: "typedef struct { }
x;"). So ensure those don't get turned into plain declarations (without
signatures) because, lacking names, they can't be resolved to the
definition.

[Also include a fix for llvm-dwarfdump/libDebugInfoDWARF to pretty print
types in type units]

llvm-svn: 360458
2019-05-10 19:15:29 +00:00
Jeremy Morse a2b780b731 [DebugInfo] Use zero linenos for debug intrinsics when promoting dbg.declare
In certain circumstances, optimizations pick line numbers from debug
intrinsic instructions as the new location for altered instructions. This
is problematic because the line number of a debugging intrinsic is
meaningless (it doesn't produce any machine instruction), only the scope
information is valid. The result can be the line number of a variable
declaration "leaking" into real code from debugging intrinsics, making the
line table un-necessarily jumpy, and potentially different with / without
variable locations.

Fix this by using zero line numbers when promoting dbg.declare intrinsics
into dbg.values: this is safe for debug intrinsics as their line numbers
are meaningless, and reduces the scope for damage / misleading stepping
when optimizations pick locations from the wrong place.

Differential Revision: https://reviews.llvm.org/D59272

llvm-svn: 360415
2019-05-10 10:03:41 +00:00
Eric Christopher c93f56d39e Temporarily Revert "[DebugInfo] Terminate more location-list ranges at the end of blocks"
as it was causing significant compile time regressions.

This reverts commit r359426 while we come up with testcases and additional ideas.

llvm-svn: 360301
2019-05-08 23:54:03 +00:00
Adrian Prantl e6e8db5e9b Debug Info: Support address space attributes on rvalue references.
DWARF5, 2.12 20ff says that

Any debugging information entry representing a pointer or reference
type [may have a DW_AT_address_class attribute].

The existing code (https://reviews.llvm.org/D29670) seems to take a
quite literal interpretation of that wording. I don't see a reason why
an rvalue reference isn't a reference type in the spirit of that
paragraph. This patch allows rvalue references to also have address
spaces.

rdar://problem/50511483

Differential Revision: https://reviews.llvm.org/D61625

llvm-svn: 360176
2019-05-07 17:42:38 +00:00
George Rimar 5c922f6988 [llvm-objdump] - Print relocation record in a GNU format.
This fixes the https://bugs.llvm.org/show_bug.cgi?id=41355.

Previously with -r we printed relocation section name instead of the target section name.
It was like this: "RELOCATION RECORDS FOR [.rel.text]"
Now it is: "RELOCATION RECORDS FOR [.text]"

Also when relocation target section has more than one relocation section,
we did not combine the output. Now we do.

Differential revision: https://reviews.llvm.org/D61312

llvm-svn: 360143
2019-05-07 13:14:18 +00:00
Paul Robinson 1e18bfe892 Fix more Windows bots after r360015.
Depending on the environment, the directory separator might
appear as \ or \\ on different bots.

http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/17446/steps/test-check-all/logs/stdio

llvm-svn: 360065
2019-05-06 19:12:25 +00:00
Fangrui Song abb066c3f9 [test] Remove redundant bracket in rL360035
llvm-svn: 360036
2019-05-06 11:43:19 +00:00
Fangrui Song a79ec7b0b2 Try fix Windows bot after rL360015
llvm-svn: 360035
2019-05-06 11:39:49 +00:00
Fangrui Song 39a0a99330 Try fix Windows bot after rL360015
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/25599/steps/test/logs/stdio

llvm-svn: 360034
2019-05-06 11:37:20 +00:00
Fangrui Song 7e55672b22 DWARF v5: fix directory index in the line table
Summary:
Prior to DWARF v5, a directory index of 0 represents DW_AT_comp_dir.

In DWARF v5, the index starts with 0 and Entry.DirIdx is the index into
Prologue.IncludeDirectories.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D61253

llvm-svn: 360015
2019-05-06 08:03:46 +00:00
Matt Arsenault b6c599afd3 Reapply r359906, "RegAllocFast: Add heuristic to detect values not live-out of a block"
This reverts commit r359912.

This should pass now, since the clang test was made less fragile in
r359918.

llvm-svn: 359919
2019-05-03 19:06:57 +00:00
Nico Weber bb852a9672 Revert r359906, "RegAllocFast: Add heuristic to detect values not live-out of a block"
Makes clang/test/Misc/backend-stack-frame-diagnostics-fallback.cpp fail.

llvm-svn: 359912
2019-05-03 18:08:03 +00:00
Matt Arsenault daf2d653fa RegAllocFast: Add heuristic to detect values not live-out of a block
Add an improved/new heuristic to catch more cases when values are not
live out of a basic block.

Patch by Matthias Braun

llvm-svn: 359906
2019-05-03 17:03:24 +00:00
Fangrui Song 6afcdcf9ab [llvm-readobj] Change -t to --symbols in tests. NFC
-t is --symbols in llvm-readobj but --section-details (unimplemented) in readelf.
The confusing option should not be used since we aim for improving
compatibility.

Keep just one llvm-readobj -t use case in test/tools/llvm-readobj/symbols.test

llvm-svn: 359661
2019-05-01 09:28:24 +00:00
Fangrui Song e29e30b139 [llvm-readobj] Change -long-option to --long-option in tests. NFC
We use both -long-option and --long-option in tests. Switch to --long-option for consistency.

In the "llvm-readelf" mode, -long-option is discouraged as it conflicts with grouped short options and it is not accepted by GNU readelf.

While updating the tests, change llvm-readobj -s to llvm-readobj -S to reduce confusion ("s" is --section-headers in llvm-readobj but --symbols in llvm-readelf).

llvm-svn: 359649
2019-05-01 05:27:20 +00:00
Don Hinton 89e583b843 [CommandLine] Don't allow unlimitted dashes for options. Part 1 or 5
Summary:
Prior to this patch, the CommandLine parser would strip an
unlimitted number of dashes from options.  This patch limits it to
two.

Reviewers: rnk

Reviewed By: rnk

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61229

llvm-svn: 359480
2019-04-29 18:34:18 +00:00
Jeremy Morse 055aee1d8a [DebugInfo] Terminate more location-list ranges at the end of blocks
This patch fixes PR40795, where constant-valued variable locations can
"leak" into blocks placed at higher addresses. The root of this is that
DbgEntityHistoryCalculator terminates all register variable locations at
the end of each block, but not constant-value variable locations.

Fixing this requires constant-valued DBG_VALUE instructions to be
broadcast into all blocks where the variable location remains valid, as
documented in the LiveDebugValues section of SourceLevelDebugging.rst,
and correct termination in DbgEntityHistoryCalculator.

Differential Revision: https://reviews.llvm.org/D59431

llvm-svn: 359426
2019-04-29 09:13:16 +00:00
Fangrui Song 763a2e1f36 [llvm-nm][llvm-readelf] Avoid single-dash -long-option in tests
llvm-svn: 359383
2019-04-27 16:12:14 +00:00
David Blaikie 832c7d9f36 DebugInfo: Emit only declarations (not whole definitions) of non-unit user defined types into type units
While this doesn't come up in reasonable cases currently (the only user
defined types not in type units are ones without linkage - which makes
for near-ODR violations, because it'd be a type with linkage referencing
a type without linkage - such a type can't be validly defined in more
than one TU, so arguably it shouldn't be in a type unit to begin with -
but it's a convenient way to demonstrate an issue that will become more
revalent with homed modular debug info type definitions - which also
don't need to be in type units but more legitimately so).

Precursor to the Clang change to de-type-unit (by omitting the
'identifier') types homed due to strong linkage vtables. (making that
change without this one would lead to major type duplication in type
units)

llvm-svn: 359122
2019-04-24 18:09:44 +00:00
David Blaikie 2f51176223 Reapply: "DebugInfo: Emit only one kind of accelerated access/name table""
Originally committed in r358931
Reverted in r358997

Seems this change made Apple accelerator tables miss names (because
names started respecting the CU NameTableKind GNU & assuming that
shouldn't produce accelerated names too), which is never correct (apple
accelerator tables don't have separators or CU lists - if present, they
must describe all names in all CUs).

Original Description:
Currently to opt in to debug_names in DWARFv5, the IR must contain
'nameTableKind: Default' which also enables debug_pubnames.

Instead, only allow one of {debug_names, apple_names, debug_pubnames,
debug_gnu_pubnames}.

nameTableKind: Default gives debug_names in DWARFv5 and greater,
debug_pubnames in v4 and earlier - and apple_names when tuning for lldb
on MachO.
nameTableKind: GNU always gives gnu_pubnames

llvm-svn: 359026
2019-04-23 19:00:45 +00:00
David Blaikie a2470a4653 Revert "DebugInfo: Emit only one kind of accelerated access/name table"
Regresses some apple_names situations - still investigating.

This reverts commit r358931.

llvm-svn: 358997
2019-04-23 15:03:24 +00:00
David Blaikie 68602ab2f3 DebugInfo: Emit only one kind of accelerated access/name table
Currently to opt in to debug_names in DWARFv5, the IR must contain
'nameTableKind: Default' which also enables debug_pubnames.

Instead, only allow one of {debug_names, apple_names, debug_pubnames,
debug_gnu_pubnames}.

nameTableKind: Default gives debug_names in DWARFv5 and greater,
debug_pubnames in v4 and earlier - and apple_names when tuning for lldb
on MachO.
nameTableKind: GNU always gives gnu_pubnames

llvm-svn: 358931
2019-04-22 22:45:11 +00:00
Vedant Kumar 282b26ec4d [GVN+LICM] Use line 0 locations for better crash attribution
This is a follow-up to r291037+r291258, which used null debug locations
to prevent jumpy line tables.

Using line 0 locations achieves the same effect, but works better for
crash attribution because it preserves the right inline scope.

Differential Revision: https://reviews.llvm.org/D60913

llvm-svn: 358791
2019-04-19 22:36:40 +00:00
Aaron Smith 994023a3f1 [DebugInfo] Combine Trivial and NonTrivial flags
Summary:
Companion to https://reviews.llvm.org/D59347


Reviewers: rnk, zturner, probinson, dblaikie, deadalnix

Subscribers: aprantl, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59348

llvm-svn: 358220
2019-04-11 20:25:10 +00:00
David Stenberg b96943b6a0 [DebugInfo] Track multiple registers in DbgEntityHistoryCalculator
Summary:
When calculating the debug value history, DbgEntityHistoryCalculator
would only keep track of register clobbering for the latest debug value
per inlined entity. This meant that preceding register-described debug
value fragments would live on until the next overlapping debug value,
ignoring any potential clobbering. This patch amends
DbgEntityHistoryCalculator so that it keeps track of all registers that
a inlined entity's currently live debug values are described by.

The DebugInfo/COFF/pieces.ll test case has had to be changed since
previously a register-described fragment would incorrectly outlive its
basic block.

The parent patch D59941 is expected to increase the coverage slightly,
as it makes sure that location list entries are inserted after clobbered
fragments, and this patch is expected to decrease it, as it stops
preceding register-described from living longer than they should. All in
all, this patch and the preceding patch has a negligible effect on the
output from `llvm-dwarfdump -statistics' for a clang-3.4 binary built
using the RelWithDebInfo build profile. "Scope bytes covered" increases
by 0.5%, and "variables with location" increases from 2212083 to
2212088, but it should improve the accuracy quite a bit.

This fixes PR40283.

Reviewers: aprantl, probinson, dblaikie, rnk, bjope

Reviewed By: aprantl

Subscribers: llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D59942

llvm-svn: 358073
2019-04-10 11:28:28 +00:00
David Stenberg 5ffec6deef [DebugInfo] Improve handling of clobbered fragments
Summary:
Currently the DbgValueHistorymap only keeps track of clobbered registers
for the last debug value that it has encountered. This could lead to
preceding register-described debug values living on longer in the
location lists than they should. See PR40283 for an example.  This
patch does not introduce tracking of multiple registers, but changes
the DbgValueHistoryMap structure to allow for that in a follow-up
patch. This patch is not NFC, as it at least fixes two bugs in
DwarfDebug (both are covered in the new clobbered-fragments.mir test):

* If a debug value was clobbered (its End pointer set), the value would
  still be added to OpenRanges, meaning that the succeeding location list
  entries could potentially contain stale values.

* If a debug value was clobbered, and there were non-overlapping
  fragments that were still live after the clobbering, DwarfDebug would
  not create a location list entry starting directly after the
  clobbering instruction. This meant that the location list could have
  a gap until the next debug value for the variable was encountered.

Before this patch, the history map was represented by <Begin, End>
pairs, where a new pair was created for each new debug value. When
dealing with partially overlapping register-described debug values, such
as in the following example:

  DBG_VALUE $reg2, $noreg, !1, !DIExpression(DW_OP_LLVM_fragment, 32, 32)
  [...]
  DBG_VALUE $reg3, $noreg, !1, !DIExpression(DW_OP_LLVM_fragment, 64, 32)
  [...]
  $reg2 = insn1
  [...]
  $reg3 = insn2

the history map would then contain the entries `[<DV1, insn1>, [<DV2, insn2>]`.
This would leave it up to the users of the map to be aware of
the relative order of the instructions, which e.g. could make
DwarfDebug::buildLocationList() needlessly complex. Instead, this patch
makes the history map structure monotonically increasing by dropping the
End pointer, and replacing that with explicit clobbering entries in the
vector. Each debug value has an "end index", which if set, points to the
entry in the vector that ends the debug value. The ending entry can
either be an overlapping debug value, or an instruction which clobbers
the register that the debug value is described by. The ending entry's
instruction can thus either be excluded or included in the debug value's
range. If the end index is not set, the debug value that the entry
introduces is valid until the end of the function.

Changes to test cases:

 * DebugInfo/X86/pieces-3.ll: The range of the first DBG_VALUE, which
   describes that the fragment (0, 64) is located in RDI, was
   incorrectly ended by the clobbering of RAX, which the second
   (non-overlapping) DBG_VALUE was described by. With this patch we
   get a second entry that only describes RDI after that clobbering.

 * DebugInfo/ARM/partial-subreg.ll: This test seems to indiciate a bug
   in LiveDebugValues that is caused by it not being aware of fragments.
   I have added some comments in the test case about that. Also, before
   this patch DwarfDebug would incorrectly include a register-described
   debug value from a preceding block in a location list entry.

Reviewers: aprantl, probinson, dblaikie, rnk, bjope

Reviewed By: aprantl

Subscribers: javed.absar, kristof.beyls, jdoerfert, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D59941

llvm-svn: 358072
2019-04-10 11:28:20 +00:00
Adrian Prantl 6ed5706a2b Add LLVM IR debug info support for Fortran COMMON blocks
COMMON blocks are a feature of Fortran that has no direct analog in C languages, but they are similar to data sections in assembly language programming. A COMMON block is a named area of memory that holds a collection of variables. Fortran subprograms may map the COMMON block memory area to their own, possibly distinct, non-empty list of variables. A Fortran COMMON block might look like the following example.

    COMMON /ALPHA/ I, J

    For this construct, the compiler generates a new scope-like DI construct (!DICommonBlock) into which variables (see I, J above) can be placed. As the common block implies a range of storage with global lifetime, the !DICommonBlock refers to a !DIGlobalVariable. The Fortran variable that comprise the COMMON block are also linked via metadata to offsets within the global variable that stands for the entire common block.

    @alpha_ = common global %alphabytes_ zeroinitializer, align 64, !dbg !27, !dbg !30, !dbg !33
    !14 = distinct !DISubprogram(…)
    !20 = distinct !DICommonBlock(scope: !14, declaration: !25, name: "alpha")
    !25 = distinct !DIGlobalVariable(scope: !20, name: "common alpha", type: !24)
    !27 = !DIGlobalVariableExpression(var: !25, expr: !DIExpression())
    !29 = distinct !DIGlobalVariable(scope: !20, name: "i", file: !3, type: !28)
    !30 = !DIGlobalVariableExpression(var: !29, expr: !DIExpression())
    !31 = distinct !DIGlobalVariable(scope: !20, name: "j", file: !3, type: !28)
    !32 = !DIExpression(DW_OP_plus_uconst, 4)
    !33 = !DIGlobalVariableExpression(var: !31, expr: !32)

    The DWARF generated for this is as follows.

    DW_TAG_common_block:
    DW_AT_name: alpha
    DW_AT_location: @alpha_+0
    DW_TAG_variable:
    DW_AT_name: common alpha
    DW_AT_type: array of 8 bytes
    DW_AT_location: @alpha_+0
    DW_TAG_variable:
    DW_AT_name: i
    DW_AT_type: integer*4
    DW_AT_location: @Alpha+0
    DW_TAG_variable:
    DW_AT_name: j
    DW_AT_type: integer*4
    DW_AT_location: @Alpha+4

Patch by Eric Schweitz!

Differential Revision: https://reviews.llvm.org/D54327

llvm-svn: 357934
2019-04-08 19:13:55 +00:00
Craig Topper 80aa2290fb [X86] Merge the different Jcc instructions for each condition code into single instructions that store the condition code as an operand.
Summary:
This avoids needing an isel pattern for each condition code. And it removes translation switches for converting between Jcc instructions and condition codes.

Now the printer, encoder and disassembler take care of converting the immediate. We use InstAliases to handle the assembly matching. But we print using the asm string in the instruction definition. The instruction itself is marked IsCodeGenOnly=1 to hide it from the assembly parser.

Reviewers: spatel, lebedev.ri, courbet, gchatelet, RKSimon

Reviewed By: RKSimon

Subscribers: MatzeB, qcolombet, eraman, hiraditya, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60228

llvm-svn: 357802
2019-04-05 19:28:09 +00:00
Paul Semel 0c27bc2e1f [DWARF] check whether the DIE is valid before querying for information
Differential Revision: https://reviews.llvm.org/D60147

llvm-svn: 357607
2019-04-03 17:13:45 +00:00
George Rimar 6da44ad75d [yaml2obj][obj2yaml] - Change how symbol's binding is descibed when parsing/dumping.
Currently, YAML has the following syntax for describing the symbols:

Symbols:
  Local:
    LocalSymbol1:
    ...
    LocalSymbol2:
    ...
  ...
  Global:
    GlobalSymbol1:
  ...
  Weak:
  ...
  GNUUnique:

I.e. symbols are grouped by their bindings. That is not very convenient,
because:

It does not allow to set a custom binding, what can be useful for producing
broken/special outputs for test cases. Adding a new binding would require to
change a syntax (what we observed when added GNUUnique recently).

It does not allow to change the order of the symbols in .symtab/.dynsym,
i.e. currently all Local symbols are placed first, then Global, Weak and GNUUnique
are following, but we are not able to change the order.

It is not consistent. Binding is just one of the properties of the symbol,
we do not group them by other properties.

It makes the code more complex that it can be. This patch shows it can be simplified
with the change performed.

The patch changes the syntax to just:

Symbols:
  Symbol1:
  ...
  Symbol2:
  ...
...

With that, we are able to work with the binding field just like with any other symbol property.

Differential revision: https://reviews.llvm.org/D60122

llvm-svn: 357595
2019-04-03 14:53:42 +00:00
Hans Wennborg 94b867dc7c Revert r357256 "[DAGCombine] Improve Lifetime node chains."
As it caused a pathological compile-time regressionin V8, see PR41352.

> Improve both start and end lifetime nodes chain dependencies.
>
> Reviewers: courbet
>
> Reviewed By: courbet
>
> Subscribers: hiraditya, llvm-commits
>
> Tags: #llvm
>
> Differential Revision: https://reviews.llvm.org/D59795

This also reverts the follow-up r357309:

> [DAGCombiner] Rewrite ImproveLifetimeNodeChain to avoid DAG loop.
>
> Avoid EXPENSIVE_CHECK failure. NFCI.

llvm-svn: 357563
2019-04-03 07:41:58 +00:00