1937 Commits

Author SHA1 Message Date
Adrian Prantl
c17aee67f1 Revert "Rename DW_AT_LLVM_isysroot to DW_AT_LLVM_sysroot"
This reverts commit 12e479475a896f664fb721f98c2d6805185ac352.

I accidentally landed this patch with the wrong commit message ...
2020-01-17 12:52:36 -08:00
Adrian Prantl
12e479475a Rename DW_AT_LLVM_isysroot to DW_AT_LLVM_sysroot
This is a purely cosmetic change that is NFC in terms of the binary
output. I bugs me that I called the attribute DW_AT_LLVM_isysroot
since the "i" is an artifact of GCC command line option syntax
(-isysroot is in the category of -i options) and doesn't carry any
useful information otherwise.

This attribute only appears in Clang module debug info.

Differential Revision: https://reviews.llvm.org/D71722
2020-01-17 09:36:48 -08:00
Vedant Kumar
f0120556c7 [DWARF] Emit DW_AT_call_return_pc as an address
This reverts D53469, which changed llvm's DWARF emission to emit
DW_AT_call_return_pc as a function-local offset. Such an encoding is not
compatible with post-link block re-ordering tools and isn't standards-
compliant.

In addition to reverting back to the original DW_AT_call_return_pc
encoding, teach lldb how to fix up DW_AT_call_return_pc when the address
comes from an object file pointed-to by a debug map. While doing this I
noticed that lldb's support for tail calls that cross a DSO/object file
boundary wasn't covered, so I added tests for that. This latter case
exercises the newly added return PC fixup.

The dsymutil changes in this patch were originally included in D49887:
the associated test should be sufficient to test DW_AT_call_return_pc
encoding purely on the llvm side.

Differential Revision: https://reviews.llvm.org/D72489
2020-01-15 13:02:23 -08:00
David Blaikie
fccac1ec16 DebugInfo: Correct the form of DW_AT_macro_info in .dwo files (sec_offset, rather than data4) 2019-12-24 01:23:21 -08:00
David Blaikie
83c7a424d9 DebugInfo: Add {} to address -Wdangling-else warning. 2019-12-24 01:14:15 -08:00
Sourabh Singh Tomar
0a72515d33 [DebugInfo] Fix v4 macinfo for dwo files.
Dwo files must contain have DW_AT_macro_info attribute, when macro information is emitted. Adjusted the test case
for the same.
2019-12-24 12:50:34 +05:30
Vedant Kumar
fa4701e197 [DWARF] Defer creating declaration DIEs until we prepare call site info
It isn't necessary to create DIEs for all of the declaration subprograms
in a CU's retainedTypes list. We can defer creating these subprograms
until we need to prepare a call site tag that refers to one.

This cleanup was mentioned in passing in D70350.
2019-12-20 15:26:31 -08:00
Vedant Kumar
79daafc903 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
Yury Delendik
adf7a0a558 [WebAssembly] Use TargetIndex operands in DbgValue to track WebAssembly operands locations
Extends DWARF expression language to express locals/globals locations. (via
target-index operands atm) (possible variants are: non-virtual registers
or address spaces)

The WebAssemblyExplicitLocals can replace virtual registers to targertindex
operand type at the time when WebAssembly backend introduces
{get,set,tee}_local instead of corresponding virtual registers.

Reviewed By: aprantl, dschuff

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D52634
2019-12-20 14:39:05 -08:00
David Blaikie
aaa5a5e7ff DebugInfo: Include DW_AT_base_addr even in gmlt with no inline functions
Since the address pool doesn't get populated in this case (due to the
lack of inlining, no child DIEs are added to the CU - so no addresses
are needed for the DIEs themselves) until the range list is emitted - at
the time the attributes are added to the CU, the address pool is empty.
So check whether the address pool will be used for the range lists & add
an addr_base if that's the case.
2019-12-18 17:14:28 -08:00
David Blaikie
64fa76ef55 Reapply "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"
Move these data structures closer together so their emission code can
eventually share more of its implementation.

Was an egregious bug (completely untested, evidently) where I hadn't
inverted a DWARFv5 test as needed, so it was doing the exact opposite of
what was required & thus tried to emit a DWARFv5 range list header in
DWARFv4.

Reapply 8e04896288d22ed8bef7ac367923374f96b753d6 which was
reverted in a8154e5e0c83d2f0f65f3b4fb1a0bc68785bd975.
2019-12-18 16:28:19 -08:00
Sourabh Singh Tomar
399273e5eb 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
Eric Christopher
a8154e5e0c Temporarily revert "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"
as it was causing bot and build failures.

This reverts commit 8e04896288d22ed8bef7ac367923374f96b753d6.
2019-12-12 17:55:41 -08:00
David Blaikie
8e04896288 NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List
Move these data structures closer together so their emission code can
eventually share more of its implementation.
2019-12-12 16:53:59 -08:00
David Blaikie
20e06a28da 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
dabd2622a8 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
56232f950d 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
caa4120906 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
David Blaikie
4ffd3f44e3 DebugInfo: Clarify some more reasons v4 loc.dwo can't share much implementation with loclists.dwo 2019-12-10 14:11:03 -08:00
Vedant Kumar
30038da15b [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
Sourabh Singh Tomar
307f60a1a3 [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
2019-12-11 02:19:27 +05:30
Sourabh Singh Tomar
fb4d8fe1a8 Recommit "[DWARF5] Start emitting DW_AT_dwo_name when -gdwarf-5 is specified."
Reviewers: dblaikie, aprantl, probinson

Tags: #debug-info #llvm

Differential Revision: https://reviews.llvm.org/D71185
2019-12-11 01:24:50 +05:30
Sourabh Singh Tomar
d82b6ba21b Revert "[DWARF5] Start emitting DW_AT_dwo_name when -gdwarf-5 is specified."
This reverts commit 6ef01588f4d75ef43da4ed2a37ba7a8b8daab259.
Missing Differetial revision.
2019-12-11 01:20:40 +05:30
Sourabh Singh Tomar
6ef01588f4 [DWARF5] Start emitting DW_AT_dwo_name when -gdwarf-5 is specified. 2019-12-11 01:18:02 +05:30
David Stenberg
6965f835b4 [DebugInfo] Make describeLoadedValue() reg aware
Summary:
Currently the describeLoadedValue() hook is assumed to describe the
value of the instruction's first explicit define. The hook will not be
called for instructions with more than one explicit define.

This commit adds a register parameter to the describeLoadedValue() hook,
and invokes the hook for all registers in the worklist.

This will allow us to for example describe instructions which produce
more than two parameters' values; e.g. Hexagon's various combine
instructions.

This also fixes situations in our downstream target where we may pass
smaller parameters in the high part of a register. If such a parameter's
value is produced by a larger copy instruction, we can't describe the
call site value using the super-register, and we instead need to know
which sub-register that should be used.

This also allows us to handle cases like this:

  $ebx = [...]
  $rdi = MOVSX64rr32 $ebx
  $esi = MOV32rr $edi
  CALL64pcrel32 @call

The hook will first be invoked for the MOV32rr instruction, which will
say that @call's second parameter (passed in $esi) is described by $edi.
As $edi is not preserved it will be added to the worklist. When we get
to the MOVSX64rr32 instruction, we need to describe two values; the
sign-extended value of $ebx -> $rdi for the first parameter, and $ebx ->
$edi for the second parameter, which is now possible.

This commit modifies the dbgcall-site-lea-interpretation.mir test case.
In the test case, the values of some 32-bit parameters were produced
with LEA64r. Perhaps we can in general cases handle such by emitting
expressions that AND out the lower 32-bits, but I have not been able to
land in a case where a LEA64r is used for a 32-bit parameter instead of
LEA64_32 from C code.

I have not found a case where it would be useful to describe parameters
using implicit defines, so in this patch the hook is still only invoked
for explicit defines of forwarding registers.

Reviewers: djtodoro, NikolaPrica, aprantl, vsk

Reviewed By: djtodoro, vsk

Subscribers: ormris, hiraditya, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D70431
2019-12-09 10:47:49 +01:00
David Stenberg
f3696533f2 Revert "[DebugInfo] Make describeLoadedValue() reg aware"
This reverts commit 3cd93a4efcdeabeb20cb7bec9fbddcb540d337a1.
I'll recommit with a well-formatted arcanist commit message.
2019-12-09 10:45:13 +01:00
David Stenberg
3cd93a4efc [DebugInfo] Make describeLoadedValue() reg aware
Currently the describeLoadedValue() hook is assumed to describe the
value of the instruction's first explicit define. The hook will not be
called for instructions with more than one explicit define.

This commit adds a register parameter to the describeLoadedValue() hook,
and invokes the hook for all registers in the worklist.

This will allow us to for example describe instructions which produce
more than two parameters' values; e.g. Hexagon's various combine
instructions.

This also fixes a case in our downstream target where we may pass
smaller parameters in the high part of a register. If such a parameter's
value is produced by a larger copy instruction, we can't describe the
call site value using the super-register, and we instead need to know
which sub-register that should be used.

This also allows us to handle cases like this:

  $ebx = [...]
  $rdi = MOVSX64rr32 $ebx
  $esi = MOV32rr $edi
  CALL64pcrel32 @call

The hook will first be invoked for the MOV32rr instruction, which will
say that @call's second parameter (passed in $esi) is described by $edi.
As $edi is not preserved it will be added to the worklist. When we get
to the MOVSX64rr32 instruction, we need to describe two values; the
sign-extended value of $ebx -> $rdi for the first parameter, and $ebx ->
$edi for the second parameter, which is now possible.

This commit modifies the dbgcall-site-lea-interpretation.mir test case.
In the test case, the values of some 32-bit parameters were produced
with LEA64r. Perhaps we can in general cases handle such by emitting
expressions that AND out the lower 32-bits, but I have not been able to
land in a case where a LEA64r is used for a 32-bit parameter instead of
LEA64_32 from C code.

I have not found a case where it would be useful to describe parameters
using implicit defines, so in this patch the hook is still only invoked
for explicit defines of forwarding registers.
2019-12-09 10:44:17 +01:00
David Blaikie
560ab1f8d3 DebugInfo: Pull out a common expression.
This is for the case where -gmlt -gsplit-dwarf -fsplit-dwarf-inlining
are used together in some but not all units during LTO (or, in the
reduced case, even without LTO) - ensuring that no split dwarf is used
(because split-dwarf-inlining puts the same data in the .o file, so
there's no need to duplicate it into the .dwo file)
2019-12-05 19:51:30 -08:00
David Blaikie
decee04e63 DebugInfo: Fix LTO+DWARFv5 loclists
The loclists_table_base was being overwritten for each CU even though
only one loclists contribution is made so everything but the last CU
would have a label that was never defined and fail to assemble.
2019-12-05 12:47:54 -08:00
David Stenberg
54682d871d [DebugInfo] Handle call site values for instructions before call bundle
Summary:
If a call is bundled then the code that looks for instructions that
produce parameter values would break when reaching the call's bundle
header, due to the `ifCall(/*AnyInBundle*/)` invocation returning true.

It is not enough to simply ignore bundle headers in the `isCall()`
invocation, as the bundle header may have defines of parameter registers
due to the call, meaning that such registers would incorrectly be
removed from the worklist. Therefore, do not look at bundle headers at
all.

Reviewers: djtodoro, NikolaPrica, aprantl, vsk

Reviewed By: aprantl, vsk

Subscribers: hiraditya, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D71024
2019-12-05 11:50:41 +01:00
Alexey Lapshin
789e257ce0 [DWARF5][Debuginfo] Compilation unit type (DW_UT_skeleton) and root DIE (DW_TAG_compile_unit) do not match.
That patch fixes incompatible compilation unit type (DW_UT_skeleton) and root DIE (DW_TAG_compile_unit) error.

cat split-dwarf.cpp
int main()
{
  int a = 1;
  return 0;
}

clang++ -O -g -gsplit-dwarf -gdwarf-5 split-dwarf.cpp; llvm-dwarfdump --verify ./a.out | grep skeleton
error: Compilation unit type (DW_UT_skeleton) and root DIE (DW_TAG_compile_unit) do not match.

The fix is to change DW_TAG_compile_unit into DW_TAG_skeleton_unit when skeleton file is generated.

Differential Revision: https://reviews.llvm.org/D70880
2019-12-05 00:53:47 +03:00
Sourabh Singh Tomar
8dd17a13b0 [NFCI][DebugInfo] Corrected a comment. 2019-12-03 19:45:37 +05:30
Sourabh Singh Tomar
3f3d0f4f4b [DebugInfo] Support for debug_macinfo.dwo section in llvm and llvm-dwarfdump.
This patch adds support for debug_macinfo.dwo section[pre-standardized]
to llvm and llvm-dwarfdump.

Reviewers: probinson, dblaikie, aprantl, jini.susan.george, alok

Differential Revision: https://reviews.llvm.org/D70705

Tags: #debug-info #llvm
2019-12-03 08:54:12 +05:30
Sourabh Singh Tomar
0e02977b6e Recommit "[DWARF] Support for loclist.dwo section in llvm and llvm-dwarfdump."
The original commit message follows.

This patch adds support for debug_loclists.dwo section in llvm and llvm-dwarfdump.
Also Fixes PR43622, PR43623.

Reviewers: dblaikie, probinson, labath, aprantl, jini.susan.george

Differential Revision: https://reviews.llvm.org/D69462
2019-11-23 20:10:23 +05:30
Sourabh Singh Tomar
02cb4b2fd6 Revert "[DWARF] Support for loclist.dwo section in llvm and llvm-dwarfdump."
This reverts commit 81b0a3284af1dcef26e56b0de9fd74002083c471.
Will Re-apply, with updated Differtial Revision, for automatic closure of
Phabricator review.
2019-11-23 19:46:07 +05:30
Sourabh Singh Tomar
81b0a3284a [DWARF] Support for loclist.dwo section in llvm and llvm-dwarfdump.
This patch adds support for debug_loclists.dwo section in llvm and llvm-dwarfdump.
Also Fixes PR43622, PR43623.

Reviewers: dblaikie, probinson, labath, aprantl, jini.susan.george

https://reviews.llvm.org/D69462
2019-11-23 10:25:11 +05:30
Thomas Preud'homme
a89ca4ae17 Fix PR44001: assert failure in getFunctionLocalOffsetAfterInsn
Summary:
Assert in getFunctionLocalOffsetAfterInsn() fails when processing a call
MachineInstr inside a bundle and compiling with debug info. This is
because labels are added by DwarfDebug::beginInstruction() which is
called for each top-level MI by EmitFunctionBody()'s for-loop iteration
but constructCallSiteEntryDIEs() which calls
getFunctionLocalOffsetAfterInsn() iterates over all MIs.

This commit modifies constructCallSiteEntryDIEs() to get the associated
bundle MI for call MIs inside a bundle and use that to when calling
getFunctionLocalOffsetAfterInsn() and getLabelAfterInsn(). It also skips
loop iterations for bundle MIs since the loop statements are concerned
with debug info for each physical instructions and bundles represent a
group of instructions. It also fix the comment about PCAddr since the
code is getting the return address and not the call address.

Reviewers: dstenb, vsk, aprantl, djtodoro, dblaikie, NikolaPrica

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70293
2019-11-19 11:23:11 +00:00
David Blaikie
77cfcd7509 DebugInfo: Use loclistx for DWARFv5 location lists to reduce the number of relocations
This only implements the non-dwo part, but loclistx is necessary to use
location lists in DWARFv5, so it's a precursor to that work - and
generally reduces relocations (only using one reloc, then
indexes/relative offsets for all location list references) in non-split
DWARF.
2019-11-15 18:51:13 -08:00
David Stenberg
7417cc149b Fix typo in DwarfDebug [NFC] 2019-11-13 18:06:16 +01:00
David Blaikie
db797bfb2b DebugInfo: Remove redundant conditionals/checks from macro info emission
These checks fall out naturally from the current implementation without
needing to be explicitly considered anymore.
2019-11-08 15:31:15 -08:00
David Blaikie
736273c7fe DebugInfo: Do not create a debug_macinfo section if no CUs have associated macros
Patch based on Sourabh Singh's D69839 patch.
2019-11-08 15:30:11 -08:00
David Blaikie
39c308f6b8 DebugInfo: Use separate macinfo contributions for each CU
The macinfo support was broken for LTO situations, by terminating
macinfo lists only once - multiple macinfo contributions were correctly
labeled, but they all continued/flowed into later contributions until
only one terminator appeared at the end of the section.

Correctly terminate each contribution & fix the parsing to handle this
situation too. The parsing fix is also necessary for dumping linked
binaries - the previous code would stop at the end of the first
contribution - missing all later contributions in a linked binary.

It'd be nice to improve the dumping to print the offsets of each
contribution so it'd be easier to know which CU AT_macro_info refers to
which macinfo contribution.
2019-11-08 13:27:00 -08:00
David Blaikie
89b7f16204 DebugInfo: Streamline debug_ranges/rnglists/rnglists.dwo emission code
More code reuse, better basis for modelling
debug_loc/loclists/loclists.dwo emission support.
2019-11-01 14:56:43 -07:00
Djordje Todorovic
532815dd5c [ARM][AArch64][DebugInfo] Improve call site instruction interpretation
Extend the describeLoadedValue() with support for target specific ARM and
AArch64 instructions interpretation. The patch provides specialization for
ADD and SUB operations that include a register and an immediate/offset
operand. Some of the instructions can operate with global string addresses
or constant pool indexes but such cases are omitted since we currently lack
flexible support for processing such operands at DWARF production stage.

Patch by Nikola Prica

Differential Revision: https://reviews.llvm.org/D67556
2019-10-30 13:58:14 +01:00
David Blaikie
2941cda5be DebugInfo: Move loclist base address from DwarfFile to DebugLocStream
There's no need to have more than one of these (there can be two
DwarfFiles - one for the .o, one for the .dwo - but only one loc/loclist
section (either in the .o or the .dwo) & certainly one per
DebugLocStream, which is currently singular in DwarfDebug)

llvm-svn: 375183
2019-10-17 23:02:19 +00:00
David Blaikie
3d737b642a DebugInfo: Remove unused parameter (from DwarfDebug.cpp:emitListsTableHeaderStart)
llvm-svn: 375180
2019-10-17 22:11:40 +00:00
David Stenberg
1ae2d9a2bd [DebugInfo] Add a DW_OP_LLVM_entry_value operation
Summary:
Internally in LLVM's metadata we use DW_OP_entry_value operations with
the same semantics as DWARF; that is, its operand specifies the number
of bytes that the entry value covers.

At the time of emitting entry values we don't know the emitted size of
the DWARF expression that the entry value will cover. Currently the size
is hardcoded to 1 in DIExpression, and other values causes the verifier
to fail. As the size is 1, that effectively means that we can only have
valid entry values for registers that can be encoded in one byte, which
are the registers with DWARF numbers 0 to 31 (as they can be encoded as
single-byte DW_OP_reg0..DW_OP_reg31 rather than a multi-byte
DW_OP_regx). It is a bit confusing, but it seems like llvm-dwarfdump
will print an operation "correctly", even if the byte size is less than
that, which may make it seem that we emit correct DWARF for registers
with DWARF numbers > 31. If you instead use readelf for such cases, it
will interpret the number of specified bytes as a DWARF expression. This
seems like a limitation in llvm-dwarfdump.

As suggested in D66746, a way forward would be to add an internal
variant of DW_OP_entry_value, DW_OP_LLVM_entry_value, whose operand
instead specifies the number of operations that the entry value covers,
and we then translate that into the byte size at the time of emission.

In this patch that internal operation is added. This patch keeps the
limitation that a entry value can only be applied to simple register
locations, but it will fix the issue with the size operand being
incorrect for DWARF numbers > 31.

Reviewers: aprantl, vsk, djtodoro, NikolaPrica

Reviewed By: aprantl

Subscribers: jyknight, fedor.sergeev, hiraditya, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D67492

llvm-svn: 374881
2019-10-15 11:31:21 +00:00
David Stenberg
284827f32b [DebugInfo] Add interface for pre-calculating the size of emitted DWARF
Summary:
DWARF's DW_OP_entry_value operation has two operands; the first is a
ULEB128 operand that specifies the size of the second operand, which is
a DWARF block. This means that we need to be able to pre-calculate and
emit the size of DWARF expressions before emitting them. There is
currently no interface for doing this in DwarfExpression, so this patch
introduces that.

When implementing this I initially thought about running through
DwarfExpression's emission two times; first with a temporary buffer to
emit the expression, in order to being able to calculate the size of
that emitted data. However, DwarfExpression is a quite complex state
machine, so I decided against that, as it seemed like the two runs could
get out of sync, resulting in incorrect size operands. Therefore I have
implemented this in a way that we only have to run DwarfExpression once.
The idea is to emit DWARF to a temporary buffer, for which it is
possible to query the size. The data in the temporary buffer can then be
emitted to DwarfExpression's main output.

In the case of DIEDwarfExpression, a temporary DIE is used. The values
are all allocated using the same BumpPtrAllocator as for all other DIEs,
and the values are then transferred to the real value list. In the case
of DebugLocDwarfExpression, the temporary buffer is implemented using a
BufferByteStreamer which emits to a buffer in the DwarfExpression
object.

Reviewers: aprantl, vsk, NikolaPrica, djtodoro

Reviewed By: aprantl

Subscribers: hiraditya, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D67768

llvm-svn: 374879
2019-10-15 11:14:35 +00:00
David Stenberg
8535bed795 [DebugInfo] Fix truncation of call site immediates
Summary:
This addresses a bug in collectCallSiteParameters() where call site
immediates would be truncated from int64_t to unsigned.

This fixes PR43525.

Reviewers: djtodoro, NikolaPrica, aprantl, vsk

Reviewed By: aprantl

Subscribers: hiraditya, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D68869

llvm-svn: 374770
2019-10-14 12:49:58 +00:00
David Blaikie
289c45cc62 DebugInfo: Use base address selection entries for debug_loc
Unify the range and loc emission (for both DWARFv4 and DWARFv5 style lists) and take advantage of that unification to use strategic base addresses for loclists.

Differential Revision: https://reviews.llvm.org/D68620

llvm-svn: 374600
2019-10-11 21:52:41 +00:00