Commit Graph

52 Commits

Author SHA1 Message Date
Fangrui Song 6d2d589b06 [MC] De-capitalize another set of MCStreamer::Emit* functions
Emit{ValueTo,Code}Alignment Emit{DTP,TP,GP}* EmitSymbolValue etc
2020-02-14 19:26:52 -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 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
Fangrui Song da82ce99b7 [DebugInfo] Delete TypedDINodeRef
TypedDINodeRef<T> is a redundant wrapper of Metadata * that is actually a T *.

Accordingly, change DI{Node,Scope,Type}Ref uses to DI{Node,Scope,Type} * or their const variants.
This allows us to delete many resolve() calls that clutter the code.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D61369

llvm-svn: 360108
2019-05-07 02:06:37 +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
David Stenberg 6feef56d1b [DebugInfo] Rename DbgValueHistoryMap::{InstrRange -> Entry}, NFC
Summary:
In an upcoming commit the history map will be changed so that it
contains explicit entries for instructions that clobber preceding debug
values, rather than Begin- End range pairs, so generalize the name to
"Entry".

Also, prefix the iterator variable names in buildLocationList() with
"E". In an upcoming commit the entry will have query functions such as
"isD(e)b(u)gValue", which could at a glance make one confuse it for
iterations over MachineInstrs, so make the iterator names a bit more
distinct to avoid that.

Reviewers: aprantl

Reviewed By: aprantl

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59939

llvm-svn: 358060
2019-04-10 09:07:43 +00:00
David Stenberg 3739979c20 [DebugInfo] Make InstrRange into a class, NFC
Summary:
Replace use of std::pair by creating a class for the debug value
instruction ranges instead. This is a preparatory refactoring for
improving handling of clobbered fragments.

In an upcoming commit the Begin pointer will become a PointerIntPair, so
it will be cleaner to have a getter for that.

Reviewers: aprantl

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59938

llvm-svn: 358059
2019-04-10 09:07:32 +00:00
David Stenberg 9dbeca3d77 [DebugInfo] Stop changing labels for register-described parameter DBG_VALUEs
Summary:
This is a follow-up to D57510. This patch stops DebugHandlerBase from
changing the starting label for the first non-overlapping,
register-described parameter DBG_VALUEs to the beginning of the
function. That code did not consider what defined the registers, which
could result in the ranges for the debug values starting before their
defining instructions. We currently do not emit debug values for
constant values directly at the start of the function, so this code is
still useful for such values, but my intention is to remove the code
from DebugHandlerBase completely when we get there. One reason for
removing it is that the code violates the history map's ranges, which I
think can make it quite confusing when troubleshooting.

In D57510, PrologEpilogInserter was amended so that parameter DBG_VALUEs
now are kept at the start of the entry block, even after emission of
prologue code. That was done to reduce the degradation of debug
completeness from this patch. PR40638 is another example, where the
lexical-scope trimming that LDV does, in combination with scheduling,
results in instructions after the prologue being left without locations.
There might be other cases where the DBG_VALUEs are pushed further down,
for which the DebugHandlerBase code may be helpful, but as it now quite
often result in incorrect locations, even after the prologue, it seems
better to remove that code, and try to work our way up with accurate
locations.

In the long run we should maybe not aim to provide accurate locations
inside the prologue. Some single location descriptions, at least those
referring to stack values, generate inaccurate values inside the
epilogue, so we maybe should not aim to achieve accuracy for location
lists. However, it seems that we now emit line number programs that can
result in GDB and LLDB stopping inside the prologue when doing line
number stepping into functions. See PR40188 for more information.

A summary of some of the changed test cases is available in PR40188#c2.

Reviewers: aprantl, dblaikie, rnk, jmorse

Reviewed By: aprantl

Subscribers: jdoerfert, jholewinski, jvesely, javed.absar, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D57511

llvm-svn: 353928
2019-02-13 09:34:07 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Yonghong Song 61b189e06f [DebugInfo] Move several private headers to include directory
This patch moved the following files in lib/CodeGen/AsmPrinter/
  AsmPrinterHandler.h
  DbgEntityHistoryCalculator.h
  DebugHandlerBase.h
to include/llvm/CodeGen directory.

Such a change will enable Target to extend DebugHandlerBase
and emit Target specific debug info sections.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D55755

llvm-svn: 349564
2018-12-18 23:10:17 +00:00
Yonghong Song f487334622 Revert "[BTF] Add BTF DebugInfo"
This reverts commit 9c6b970db8bc63b28ce58a129bb1580a6a3c6caf.

llvm-svn: 348004
2018-11-30 16:54:43 +00:00
Yonghong Song 81b77e9159 [BTF] Add BTF DebugInfo
This patch adds BPF Debug Format (BTF) as a standalone
LLVM debuginfo. The BTF related sections are directly
generated from IR. The BTF debuginfo is generated
only when the compilation target is BPF.

What is BTF?
============

First, the BPF is a linux kernel virtual machine
and widely used for tracing, networking and security.
  https://www.kernel.org/doc/Documentation/networking/filter.txt
  https://cilium.readthedocs.io/en/v1.2/bpf/

BTF is the debug info format for BPF, introduced in the below
linux patch
  69b693f0ae (diff-06fb1c8825f653d7e539058b72c83332)
in the patch set mentioned in the below lwn article.
  https://lwn.net/Articles/752047/

The BTF format is specified in the above github commit.
In summary, its layout looks like
  struct btf_header
  type subsection (a list of types)
  string subsection (a list of strings)

With such information, the kernel and the user space is able to
pretty print a particular bpf map key/value. One possible example below:
  Withtout BTF:
    key: [ 0x01, 0x01, 0x00, 0x00 ]
  With BTF:
    key: struct t { a : 1; b : 1; c : 0}
  where struct is defined as
    struct t { char a; char b; short c; };

How BTF is generated?
=====================

Currently, the BTF is generated through pahole.
  https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=68645f7facc2eb69d0aeb2dd7d2f0cac0feb4d69
and available in pahole v1.12
  https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=4a21c5c8db0fcd2a279d067ecfb731596de822d4

Basically, the bpf program needs to be compiled with -g with
dwarf sections generated. The pahole is enhanced such that
a .BTF section can be generated based on dwarf. This format
of the .BTF section matches the format expected by
the kernel, so a bpf loader can just take the .BTF section
and load it into the kernel.
  8a138aed4a

The .BTF section layout is also specified in this patch:
with file include/llvm/BinaryFormat/BTF.h.

What use cases this patch tries to address?
===========================================

Currently, only the bpf instruction stream is required to
pass to the kernel. The kernel verifies it, jits it if configured
to do so, attaches it to a particular kernel attachment point,
and later executes when a particular event happens.

This patch tries to expand BTF to support two more use cases below:
  (1). BPF supports subroutine calls.
       During performance analysis, it would be good to
       differentiate which call is hot instead of just
       providing a virtual address. This would require to
       pass a unique identifier for each subroutine to
       the kernel, the subroutine name is a natual choice.
  (2). If a particular jitted instruction is hot, we want
       user to know which source line this jitted instruction
       belongs to. This would require the source information
       is available to various profiling tools.

Note that in a single ELF file,
  . there may be multiple loadable bpf programs,
  . for a particular to-be-loaded bpf instruction stream,
    its instructions may come from multiple PROGBITS sections,
    the bpf loader needs to merge them together to a single
    consecutive insn stream before loading to the kernel.
For example:
  section .text: subroutines funcFoo
  section _progA: calling funcFoo
  section _progB: calling funcFoo
The bpf loader could construct two loadable bpf instruction
streams and load them into the kernel:
  . _progA funcFoo
  . _progB funcFoo
So per ELF section function offset and instruction offset
will need to be adjusted before passing to the kernel, and
the kernel essentially expect only one code section regardless
of how many in the ELF file.

What do we propose and Why?
===========================

To support the above two use cases, we propose to
add an additional section, .BTF.ext, to the ELF file
which is the input of the bpf loader. A different section
is preferred since loader may need to manipulate it before
loading part of its data to the kernel.

The .BTF.ext section has a similar header to the .BTF section
and it contains two subsections for func_info and line_info.
  . the func_info maps the func insn byte offset to a func
    type in the .BTF type subsection.
  . the line_info maps the insn byte offset to a line info.
  . both func_info and line_info subsections are organized
    by ELF PROGBITS AX sections.

pahole is not a good place to implement .BTF.ext as
pahole is mostly for structure hole information and more
importantly, we want to pass the actual code to the kernel.
  . bpf program typically is small so storage overhead
    should be small.
  . in bpf land, it is totally possible that
    an application loads the bpf program into the
    kernel and then that application quits, so
    holding debug info by the user space application
    is not practical as you may not even know who
    loads this bpf program.
  . having source codes directly kept by kernel
    would ease deployment since the original source
    code does not need ship on every hosts and
    kernel-devel package does not need to be
    deployed even if kernel headers are used.

LLVM is a good place to implement.
  . The only reliable time to get the source code is
    during compilation time. This will result in both more
    accurate information and easier deployment as
    stated in the above.
  . Another consideration is for JIT. The project like bcc
    (https://github.com/iovisor/bcc)
    use MCJIT to compile a C program into bpf insns and
    load them to the kernel. The llvm generated BTF sections
    will be readily available for such cases as well.

Design and implementation of emiting .BTF/.BTF.ext sections
===========================================================

The BTF debuginfo format is defined. Both .BTF and .BTF.ext
sections are generated directly from IR when both
"-target bpf" and "-g" are specified. Note that
dwarf sections are still generated as dwarf is used
by user space tools like llvm-objdump etc. for BPF target.

This patch also contains tests to verify generated
.BTF and .BTF.ext sections for all supported types, func_info
and line_info subsections. The patch is also tested
against linux kernel bpf sample tests and selftests.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D53736

llvm-svn: 347999
2018-11-30 16:22:59 +00:00
Vedant Kumar 74533bd3b8 [DWARF] Use a function-local offset for AT_call_return_pc
Logs provided by @stella.stamenova indicate that on Linux, lldb adds a
spurious slide offset to the return PC it loads from AT_call_return_pc
attributes (see the list thread: "[PATCH] D50478: Add support for
artificial tail call frames").

This patch side-steps the issue by getting rid of the load address
calculation in lldb's CallEdge::GetReturnPCAddress.

The idea is to have the DWARF writer emit function-local offsets to the
instruction after a call. I.e. return-pc = label-after-call-insn -
function-entry. LLDB can simply add this offset to the base address of a
function to get the return PC.

Differential Revision: https://reviews.llvm.org/D53469

llvm-svn: 344960
2018-10-22 21:44:21 +00:00
Hsiangkai Wang 2532ac880a [DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)
There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

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

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

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

It also generates label debug information under global isel.

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

llvm-svn: 340039
2018-08-17 15:22:04 +00:00
Bruno Cardoso Lopes f446282aad Revert "[DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)"
This reverts commit cb8c5e417d55141f3f079a8a876e786f44308336 / r339676.

This causing a test to fail in http://green.lab.llvm.org/green/job/clang-stage1-configure-RA/48406/

    LLVM :: DebugInfo/Generic/debug-label.ll

llvm-svn: 339700
2018-08-14 17:54:41 +00:00
Hsiangkai Wang ccae278938 [DebugInfo] Generate DWARF debug information for labels. (Fix leak problems)
There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

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

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

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

It also generates label debug information under global isel.

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

llvm-svn: 339676
2018-08-14 13:50:59 +00:00
Vlad Tsyrklevich 48ed9acede Revert "[DebugInfo] Generate DWARF debug information for labels."
This reverts commits r338390 and r338398, they were causing LSan
failures on the ASan bot.

llvm-svn: 338408
2018-07-31 18:10:37 +00:00
Hsiangkai Wang cbc58ada99 [DebugInfo] Generate DWARF debug information for labels.
There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

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

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

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

It also generates label debug information under global isel.

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

llvm-svn: 338390
2018-07-31 14:48:32 +00:00
Shiva Chen f5938bfbf9 Revert "[DebugInfo] Generate DWARF debug information for labels."
This reverts commit b454fa1b4079b6c0a5b1565982d16516385838d7.

llvm-svn: 337812
2018-07-24 06:17:45 +00:00
Shiva Chen d6b2cdf9d4 [DebugInfo] Generate DWARF debug information for labels.
There are two forms for label debug information in DWARF format.

1. Labels in a non-inlined function:

DW_TAG_label
  DW_AT_name
  DW_AT_decl_file
  DW_AT_decl_line
  DW_AT_low_pc

2. Labels in an inlined function:

DW_TAG_label
  DW_AT_abstract_origin
  DW_AT_low_pc

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

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

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

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

Patch by Hsiangkai Wang.

llvm-svn: 337799
2018-07-24 02:22:55 +00:00
Vedant Kumar 7224c08141 Add a debug dump for DbgValueHistoryMap
This makes it easier to inspect the results of
DbgValueHistoryCalculator.

Differential Revision: https://reviews.llvm.org/D47663

llvm-svn: 333801
2018-06-01 22:33:15 +00:00
Bjorn Pettersson a223f815dd [SelectionDAG] Improve handling of dangling debug info
Summary:
1) Make sure to discard dangling debug info if the variable (or
variable fragment) is mapped to something new before we had a
chance to resolve the dangling debug info.

2) When resolving debug info, make sure to bump the associated
SDNodeOrder to ensure that the DBG_VALUE is emitted after the
instruction that defines the value used in the DBG_VALUE.
This will avoid a debug-use before def scenario as seen in
https://bugs.llvm.org/show_bug.cgi?id=36417.

The new test case, test/DebugInfo/X86/sdag-dangling-dbgvalue.ll,
show some other limitations in how dangling debug info is
handled in the SelectionDAG. Since we currently only support
having one dangling dbg.value per Value, we will end up dropping
debug info when there are more than one variable that is described
by the same "dangling value".

Reviewers: aprantl

Reviewed By: aprantl

Subscribers: aprantl, eraman, llvm-commits, JDevlieghere

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D44369

llvm-svn: 327303
2018-03-12 18:02:39 +00:00
Adrian McCarthy 74bfafa10e Re-land "Fix faulty assertion in debug info"
This had been reverted because the new test failed on non-X86 bots.  I moved
the new test to the appropriate subdirectory to correct this.

Differential Revision: https://reviews.llvm.org/D41264
Original submission:  r321122 (which was reverted by r321125)

This reverts commit 3c1639b5703c387a0d8cba2862803b4e68dff436.

llvm-svn: 321911
2018-01-05 23:01:04 +00:00
Adrian McCarthy 86795d9166 Revert "Fix faulty assertion in debug info"
This reverts commit e32def3f7ebe1136b7038336eff56a415a962bf2.

llvm-svn: 321125
2017-12-19 23:34:37 +00:00
Adrian McCarthy 2ed8f36834 Fix faulty assertion in debug info
It appears the code uses nullptr to represent a void type in debug metadata,
which led to an assertion failure when building DeltaAlgorithm.cpp with a
self-hosted clang on Windows.

I'm not sure why/if the problem was Windows-specific.

Fixes bug https://bugs.llvm.org/show_bug.cgi?id=35543

Differential Revision: https://reviews.llvm.org/D41264

llvm-svn: 321122
2017-12-19 23:01:17 +00:00
Matthias Braun f1caa2833f MachineFunction: Return reference from getFunction(); NFC
The Function can never be nullptr so we can return a reference.

llvm-svn: 320884
2017-12-15 22:22:58 +00:00
David Blaikie b3bde2ea50 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00
Reid Kleckner 08f5fd51cc [codeview] Generalize DIExpression parsing to handle load chains
Summary:
Hopefully this also clarifies exactly when and why we're rewriting
certiain S_LOCALs using reference types: We're using the reference type
to stand in for a zero-offset load.

Reviewers: inglorion

Subscribers: llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D37309

llvm-svn: 312247
2017-08-31 15:56:49 +00:00
Bob Haarman 1a4cbbe49f [codeview] make DbgVariableLocation::extractFromMachineInstruction use Optional
Summary:
DbgVariableLocation::extractFromMachineInstruction originally
returned a boolean indicating success. This change makes it return
an Optional<DbgVariableLocation> so we cannot try to access the fields
of the struct if they aren't valid.

Reviewers: aprantl, rnk, zturner

Subscribers: llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D37279

llvm-svn: 312143
2017-08-30 17:50:21 +00:00
Bob Haarman 68e460194a [codeview] add missing break in CodeGen/AsmPrinter/DebugHandlerBase.cpp
llvm-svn: 312055
2017-08-29 22:54:31 +00:00
Bob Haarman 223303c5a3 Reland r311957 [codeview] support more DW_OPs for more complete debug info
Summary:
Some variables show up in Visual Studio as "optimized out" even in -O0
-Od builds. This change fixes two issues that would cause this to
happen. The first issue is that not all DIExpressions we generate were
recognized by the CodeView writer. This has been addressed by adding
support for DW_OP_constu, DW_OP_minus, and DW_OP_plus. The second
issue is that we had no way to encode DW_OP_deref in CodeView. We get
around that by changinge the type we encode in the debug info to be
a reference to the type in the source code.

This fixes PR34261.

The reland adds two extra checks to the original: It checks if the
DbgVariableLocation is valid before checking any of its fields, and
it only emits ranges with nonzero registers.

Reviewers: aprantl, rnk, zturner

Reviewed By: rnk

Subscribers: mgorny, llvm-commits, aprantl, hiraditya

Differential Revision: https://reviews.llvm.org/D36907

llvm-svn: 312034
2017-08-29 20:59:25 +00:00
Bob Haarman 0bf0d66682 Revert "[codeview] support more DW_OPs for more complete debug info"
This reverts commit e160912f53f047bc97e572add179e08e33f4df48.

llvm-svn: 311977
2017-08-29 04:08:31 +00:00
Bob Haarman b2a04a1513 [codeview] support more DW_OPs for more complete debug info
Summary:
Some variables show up in Visual Studio as "optimized out" even in -O0
-Od builds. This change fixes two issues that would cause this to
happen. The first issue is that not all DIExpressions we generate were
recognized by the CodeView writer. This has been addressed by adding
support for DW_OP_constu, DW_OP_minus, and DW_OP_plus. The second
issue is that we had no way to encode DW_OP_deref in CodeView. We get
around that by changinge the type we encode in the debug info to be
a reference to the type in the source code.

This fixes PR34261.

Reviewers: aprantl, rnk, zturner

Reviewed By: rnk

Subscribers: mgorny, llvm-commits, aprantl, hiraditya

Differential Revision: https://reviews.llvm.org/D36907

llvm-svn: 311957
2017-08-29 00:06:59 +00:00
Benjamin Kramer debb3c35e0 Make helper functions static. NFC.
llvm-svn: 304029
2017-05-26 20:09:00 +00:00
Adrian Prantl fb31da1306 Don't generate line&scope debug info for meta-instructions.
MachineInstructions that don't generate any code (such as
IMPLICIT_DEFs) should not generate any debug info either.

Fixes PR33107.

https://bugs.llvm.org/show_bug.cgi?id=33107

This reapplies r303566 without any modifications. The stage2 build
failures persisted even after reverting this patch, and looking back
through history, it looks like these tests are flaky.

llvm-svn: 303575
2017-05-22 20:47:09 +00:00
Adrian Prantl 334a130a6f Revert "Don't generate line&scope debug info for meta-instructions."
This reverts commit r303566 while investigating a stage2 buildbot failure.

llvm-svn: 303570
2017-05-22 18:50:12 +00:00
Adrian Prantl 4c047f8931 Don't generate line&scope debug info for meta-instructions.
MachineInstructions that don't generate any code (such as
IMPLICIT_DEFs) should not generate any debug info either.

Fixes PR33107.

https://bugs.llvm.org/show_bug.cgi?id=33107

llvm-svn: 303566
2017-05-22 16:21:02 +00:00
Reid Kleckner 5bc8543a36 [codeview] Fix assertion failure introduced in r295354 refactoring
CodeViewDebug sets Asm to nullptr to disable debug info generation.  You
can get a .ll file like no-cus.ll from 'clang -gcodeview -g0', which
happens in the ubsan test suite.

llvm-svn: 302923
2017-05-12 17:02:40 +00:00
Adrian Prantl 8f3337950e Zero-Initialize PrevInstBB when entering a new MachineFunction.
It is not guaranteed that the memory used for MachineBasicBlocks in
the previous MachineFunction hasn't been freed, so holding on to a
pointer to the last function's isn't correct. Particularly I have
observed the sret.ll testcase failing because the first BasicBlock in
the new function happened to be allocated to the exact same memory as
the previously saved and (deleted) PrevInstBB.

llvm-svn: 298642
2017-03-23 20:23:42 +00:00
David Blaikie b2fbb4b276 Refactor DebugHandlerBase a bit to common non-debug-having-function filtering
llvm-svn: 295354
2017-02-16 18:48:33 +00:00
Adrian Prantl 49797ca6be Refactor the DIExpression fragment query interface (NFC)
... so it becomes available to DIExpressionCursor.

llvm-svn: 290322
2016-12-22 05:27:12 +00:00
Paul Robinson ac7fe5e0c4 Recommit r288212: Emit 'no line' information for interesting 'orphan' instructions.
DWARF specifies that "line 0" really means "no appropriate source
location" in the line table.  By default, use this for branch targets
and some other cases that have no specified source location, to
prevent inheriting unfortunate line numbers from physically preceding
instructions (which might be from completely unrelated source).

Updated patch allows enabling or suppressing this behavior for all
unspecified source locations.

Differential Revision: http://reviews.llvm.org/D24180

llvm-svn: 289468
2016-12-12 20:49:11 +00:00
Adrian Prantl 941fa7588b [DIExpression] Introduce a dedicated DW_OP_LLVM_fragment operation
so we can stop using DW_OP_bit_piece with the wrong semantics.

The entire back story can be found here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161114/405934.html

The gist is that in LLVM we've been misinterpreting DW_OP_bit_piece's
offset field to mean the offset into the source variable rather than
the offset into the location at the top the DWARF expression stack. In
order to be able to fix this in a subsequent patch, this patch
introduces a dedicated DW_OP_LLVM_fragment operation with the
semantics that we used to apply to DW_OP_bit_piece, which is what we
actually need while inside of LLVM. This patch is complete with a
bitcode upgrade for expressions using the old format. It does not yet
fix the DWARF backend to use DW_OP_bit_piece correctly.

Implementation note: We discussed several options for implementing
this, including reserving a dedicated field in DIExpression for the
fragment size and offset, but using an custom operator at the end of
the expression works just fine and is more efficient because we then
only pay for it when we need it.

Differential Revision: https://reviews.llvm.org/D27361
rdar://problem/29335809

llvm-svn: 288683
2016-12-05 18:04:47 +00:00
Kostya Serebryany b66cb88c2e revert r288283 as it causes debug info (line numbers) to be lost in instrumented code. also revert r288299 which was a workaround for the problem.
llvm-svn: 288300
2016-12-01 02:06:56 +00:00
Paul Robinson 37a13ddb4b Recommit r288212: Emit 'no line' information for interesting 'orphan' instructions.
The LLDB tests are now ready for this patch.

DWARF specifies that "line 0" really means "no appropriate source
location" in the line table.  Use this for branch targets and some
other cases that have no specified source location, to prevent
inheriting unfortunate line numbers from physically preceding
instructions (which might be from completely unrelated source).

Differential Revision: http://reviews.llvm.org/D24180

llvm-svn: 288283
2016-11-30 22:49:55 +00:00
Paul Robinson 957ba405e8 Revert r288212 due to lldb failure.
llvm-svn: 288216
2016-11-29 23:20:35 +00:00
Paul Robinson 96de8c778b Emit 'no line' information for interesting 'orphan' instructions.
DWARF specifies that "line 0" really means "no appropriate source
location" in the line table.  Use this for branch targets and some
other cases that have no specified source location, to prevent
inheriting unfortunate line numbers from physically preceding
instructions (which might be from completely unrelated source).

Differential Revision: http://reviews.llvm.org/D24180

llvm-svn: 288212
2016-11-29 22:41:16 +00:00
Victor Leschuk e1156c2eb0 DebugInfo: make DW_TAG_atomic_type valid
DW_TAG_atomic_type was already included in Dwarf.defs and emitted correctly,
however Verifier didn't recognize it as valid.
Thus we introduce the following changes:

  * Make DW_TAG_atomic_type valid tag for IR and DWARF (enabled only with -gdwarf-5)
  * Add it to related docs
  * Add DebugInfo tests

Differential Revision: https://reviews.llvm.org/D26144

llvm-svn: 285624
2016-10-31 19:09:38 +00:00
Reid Kleckner a5b1eef846 [MC] Move .cv_loc management logic out of MCContext
MCContext already has many tasks, and separating CodeView out from it is
probably a good idea. The .cv_loc tracking was modelled on the DWARF
tracking which lived directly in MCContext.

Removes the inclusion of MCCodeView.h from MCContext.h, so now there are
only 10 build actions while I hack on CodeView support instead of 265.

llvm-svn: 279847
2016-08-26 17:58:37 +00:00
Amjad Aboud acee568545 [codeview] Improved array type support.
Added support for:
1. Multi dimension array.
2. Array of structure type, which previously was declared incompletely.
3. Dynamic size array.
4. Array where element type is a typedef, volatile or constant (this should resolve PR28311).

Differential Revision: http://reviews.llvm.org/D21526

llvm-svn: 275167
2016-07-12 12:06:34 +00:00