207 Commits

Author SHA1 Message Date
stozer
1187611a04 [DebugInfo] Correctly handle salvaged casts and split fragments at ISel
Previously, LLVM had no functional way of performing casts inside of a
DIExpression(), which made salvaging cast instructions other than Noop
casts impossible. This patch enables the salvaging of casts by using the
DW_OP_LLVM_convert operator for SExt and Trunc instructions.

There is another issue which is exposed by this fix, in which fragment
DIExpressions (which are preserved more readily by this patch) for
values that must be split across registers in ISel trigger an assertion,
as the 'split' fragments extend beyond the bounds of the fragment
DIExpression causing an error. This patch also fixes this issue by
checking the fragment status of DIExpressions which are to be split, and
dropping fragments that are invalid.
2019-12-18 11:09:18 +00:00
stozer
afaad946a7 [DebugInfo] Make DebugVariable class available in DebugInfoMetadata
The DebugVariable class is a class declared in LiveDebugValues.cpp which
is used to uniquely identify a single variable, using its source
variable, inline location, and fragment info to do so. This patch moves
this class into DebugInfoMetadata.h, making it available in a much
broader scope.
2019-12-03 15:10:56 +00:00
stozer
198a91ed95 [DebugInfo] Disallow fragmenting DIExpressions with shift operators
DIExpressions with shift operators should not be fragmented for the same
reason as arithmetic operators: carry over cannot be expressed from one
fragment to the other, so an invalid result would be produced.

Differential Revision: https://reviews.llvm.org/D70601
2019-11-26 16:12:22 +00:00
David Stenberg
cb47dbbe79 [DebugInfo] Refactor DIExpression [SZ]Ext creation into function [NFC]
Summary:
Also, replace the SmallVector with a normal C array.

Reviewers: vsk

Reviewed By: vsk

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70498
2019-11-21 10:44:04 +01:00
Bjorn Pettersson
4d274621ba [DebugInfo] Fix for DW_OP_LLVM_fragment in DIExpression::isImplicit()
DIExpression::isImplicit() did not handle DW_OP_LLVM_fragment
correctly. It was scanning the elements in the expression by
iterating from the end. But we do not know the position of
ops unless we iterate from the beginning of the expression,
since DW_OP:s and their operands are stored flat in the expression
list. The old code also assumed that a DW_OP_LLVM_fragment
only occupied one element in the expression list, but it actually
occupies three elements.
2019-11-03 17:37:49 +01:00
David Stenberg
49e133c5a7 [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
Simon Pilgrim
5291c85727 DIExpression::createFragmentExpression - silence static analyzer DIExpression* null dereference warning with an assertion. NFCI.
llvm-svn: 373326
2019-10-01 11:25:38 +00:00
Djordje Todorovic
30604a8ec2 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
Djordje Todorovic
4cf81cc46f 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
Djordje Todorovic
0eecf47aa8 [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
75cb40612e [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
a77a0a3548 [DWARF] Handle the DW_OP_entry_value operand
Add the IR and the AsmPrinter parts for handling of the DW_OP_entry_values
DWARF operation.

([11/13] 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/D60866

llvm-svn: 364542
2019-06-27 13:52:34 +00:00
Peter Collingbourne
93adc422a8 hwasan: Add a tag_offset DWARF attribute to instrumented stack variables.
The goal is to improve hwasan's error reporting for stack use-after-return by
recording enough information to allow the specific variable that was accessed
to be identified based on the pointer's tag. Currently we record the PC and
lower bits of SP for each stack frame we create (which will eventually be
enough to derive the base tag used by the stack frame) but that's not enough
to determine the specific tag for each variable, which is the stack frame's
base tag XOR a value (the "tag offset") that is unique for each variable in
a function.

In IR, the tag offset is most naturally represented as part of a location
expression on the llvm.dbg.declare instruction. However, the presence of the
tag offset in the variable's actual location expression is likely to confuse
debuggers which won't know about tag offsets, and moreover the tag offset
is not required for a debugger to determine the location of the variable on
the stack, so at the DWARF level it is represented as an attribute so that
it will be ignored by debuggers that don't know about it.

Differential Revision: https://reviews.llvm.org/D63119

llvm-svn: 363635
2019-06-17 23:39:41 +00:00
Petar Jovanovic
d7ad094df9 [DebugInfoMetadata] Refactor DIExpression::prepend constants (NFC)
Refactor DIExpression::With* into a flag enum in order to be less
error-prone to use (as discussed on D60866).

Patch by Djordje Todorovic.

Differential Revision: https://reviews.llvm.org/D61943

llvm-svn: 361137
2019-05-20 10:35:57 +00:00
Fangrui Song
4dc78253e5 [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
Markus Lavin
b5d9d3a18f [DebugInfo] DW_OP_deref_size in PrologEpilogInserter.
The PrologEpilogInserter need to insert a DW_OP_deref_size before
prepending a memory location expression to an already implicit
expression to avoid having the existing expression act on the memory
address instead of the value behind it.

The reason for using DW_OP_deref_size and not plain DW_OP_deref is that
big-endian targets need to read the right size as simply truncating a
larger read would yield the wrong result (LSB bytes are not at the lower
address).

This re-commit fixes issues reported in the first one. Namely deref was
inserted under wrong conditions and additionally the deref_size argument
was incorrectly encoded.

Differential Revision: https://reviews.llvm.org/D59687

llvm-svn: 359535
2019-04-30 07:58:57 +00:00
Hans Wennborg
b4cf000aff Revert r358268 "[DebugInfo] DW_OP_deref_size in PrologEpilogInserter."
It causes clang to crash while building Chromium. See https://crbug.com/952230
for reproducer.

> The PrologEpilogInserter need to insert a DW_OP_deref_size before
> prepending a memory location expression to an already implicit
> expression to avoid having the existing expression act on the memory
> address instead of the value behind it.
>
> The reason for using DW_OP_deref_size and not plain DW_OP_deref is that
> big-endian targets need to read the right size as simply truncating a
> larger read would yield the wrong result (LSB bytes are not at the lower
> address).
>
> Differential Revision: https://reviews.llvm.org/D59687

llvm-svn: 358281
2019-04-12 12:54:52 +00:00
Markus Lavin
850d50100b [DebugInfo] DW_OP_deref_size in PrologEpilogInserter.
The PrologEpilogInserter need to insert a DW_OP_deref_size before
prepending a memory location expression to an already implicit
expression to avoid having the existing expression act on the memory
address instead of the value behind it.

The reason for using DW_OP_deref_size and not plain DW_OP_deref is that
big-endian targets need to read the right size as simply truncating a
larger read would yield the wrong result (LSB bytes are not at the lower
address).

Differential Revision: https://reviews.llvm.org/D59687

llvm-svn: 358268
2019-04-12 08:23:55 +00:00
Adrian Prantl
b613a7a943 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
Markus Lavin
cc6ad63452 [DebugInfo] Introduce DW_OP_LLVM_convert
Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.

The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.

For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.

This is a recommit of r356442 with trivial fixes for the failing tests.

Differential Revision: https://reviews.llvm.org/D56587

llvm-svn: 356451
2019-03-19 13:16:28 +00:00
Markus Lavin
b3473f4c0a Revert "[DebugInfo] Introduce DW_OP_LLVM_convert"
This reverts commit 1cf4b593a7ebd666fc6775f3bd38196e8e65fafe.

Build bots found failing tests not detected locally.

Failing Tests (3):
  LLVM :: DebugInfo/Generic/convert-debugloc.ll
  LLVM :: DebugInfo/Generic/convert-inlined.ll
  LLVM :: DebugInfo/Generic/convert-linked.ll

llvm-svn: 356444
2019-03-19 09:17:28 +00:00
Markus Lavin
08a34614fa [DebugInfo] Introduce DW_OP_LLVM_convert
Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.

The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.

For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.

Differential Revision: https://reviews.llvm.org/D56587

llvm-svn: 356442
2019-03-19 08:48:19 +00:00
Alexey Bataev
308478161b [DEBUG_INFO][NVPTX] Generate DW_AT_address_class to get the values in debugger.
Summary:
According to
https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf,
the compiler should emit the DW_AT_address_class attribute for all
variable and parameter. It means, that DW_AT_address_class attribute
should be used in the non-standard way to support compatibility with the
cuda-gdb debugger.
Clang is able to generate the information about the variable address
class. This information is emitted as the expression sequence
`DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef`. The patch
tries to find all such expressions and transform them into
`DW_AT_address_class <DWARF Address Space>` if target is NVPTX and the debugger is gdb.
If the expression is not found, then default values are used. For the
local variables <DWARF Address Space> is set to ADDR_local_space(6), for
the globals <DWARF Address Space> is set to ADDR_global_space(5). The
values are taken from the table in the same section 5.2. CUDA-Specific
DWARF Definitions.

Reviewers: echristo, probinson

Subscribers: jholewinski, aprantl, llvm-commits

Differential Revision: https://reviews.llvm.org/D57157

llvm-svn: 353203
2019-02-05 19:33:47 +00:00
Chandler Carruth
ae65e281f3 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
Mircea Trofin
e3e03a7c34 [llvm] API for encoding/decoding DWARF discriminators.
Summary:
Added a pair of APIs for encoding/decoding the 3 components of a DWARF discriminator described in http://lists.llvm.org/pipermail/llvm-dev/2016-October/106532.html: the base discriminator, the duplication factor (useful in profile-guided optimization) and the copy index (used to identify copies of code in cases like loop unrolling)

The encoding packs 3 unsigned values in 32 bits. This CL addresses 2 issues:
- communicates overflow back to the user
- supports encoding all 3 components together. Current APIs assume a sequencing of events. For example, creating a new discriminator based on an existing one by changing the base discriminator was not supported.

Reviewers: davidxl, danielcdh, wmi, dblaikie

Reviewed By: dblaikie

Subscribers: zzheng, dmgreen, aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D55681

llvm-svn: 349973
2018-12-21 22:48:50 +00:00
Paul Robinson
9276bb5427 Comment tweak requested in code review. NFC
I forgot to do this before committing D54755.

llvm-svn: 347918
2018-11-29 21:13:51 +00:00
Paul Robinson
f2c09f1782 [DebugInfo] IR/Bitcode changes for DISubprogram flags.
Packing the flags into one bitcode word will save effort in
adding new flags in the future.

Differential Revision: https://reviews.llvm.org/D54755

llvm-svn: 347806
2018-11-28 21:14:32 +00:00
Paul Robinson
b7faae8e04 [DebugInfo] DISubprogram flags get their own flags word. NFC.
This will hold flags specific to subprograms. In the future
we could potentially free up scarce bits in DIFlags by moving
subprogram-specific flags from there to the new flags word.

This patch does not change IR/bitcode formats, that will be
done in a follow-up.

Differential Revision: https://reviews.llvm.org/D54597

llvm-svn: 347239
2018-11-19 18:29:28 +00:00
David Blaikie
1e47d1d24b DebugInfo: Add a CU metadata attribute for use of DWARF ranges base address specifiers
Summary:
Ranges base address specifiers can save a lot of object size in
relocation records especially in optimized builds.

For an optimized self-host build of Clang with split DWARF and debug
info compression in object files, but uncompressed debug info in the
executable, this change produces about 18% smaller object files and 6%
larger executable.

While it would've been nice to turn this on by default, gold's 32 bit
gdb-index support crashes on this input & I don't think there's any
perfect heuristic to implement solely in LLVM that would suffice - so
we'll need a flag one way or another (also possible people might want to
aggressively optimized for executable size that contains debug info
(even with compression this would still come at some cost to executable
size)) - so let's plumb it through.

Differential Revision: https://reviews.llvm.org/D54242

llvm-svn: 346788
2018-11-13 20:08:10 +00:00
Matthew Voss
843987e0bf Emit template type and value parameter DIEs for template variables.
Summary:
Ensure the TemplateParam attribute of the DIGlobalVariable node is translated into the proper DIEs.

Resolves https://bugs.llvm.org/show_bug.cgi?id=22119

Reviewers: dblaikie, probinson, aprantl, JDevlieghere, clayborg, whitequark, deadalnix

Reviewed By: dblaikie

Subscribers: llvm-commits

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D52057

llvm-svn: 343706
2018-10-03 18:44:53 +00:00
Calixte Denizet
79a1f91df9 [IR] Add a boolean field in DILocation to know if a line must covered or not
Summary:
Some lines have a hit counter where they should not have one.
For example, in C++, some cleanup is adding at the end of a scope represented by a '}'.
So such a line has a hit counter where a user expects to not have one.
The goal of the patch is to add this information in DILocation which is used to get the covered lines in GCOVProfiling.cpp.
A following patch in clang will add this information when generating IR (https://reviews.llvm.org/D49916).

Reviewers: marco-c, davidxl, vsk, javed.absar, rnk

Reviewed By: rnk

Subscribers: eraman, xur, danielcdh, aprantl, rnk, dblaikie, #debug-info, vsk, llvm-commits, sylvestre.ledru

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D49915

llvm-svn: 342631
2018-09-20 08:53:06 +00:00
Adrian Prantl
ac9b6078f3 Prevent DILocation::getMergedLocation() from creating invalid metadata.
The function's new implementation from r340583 had a bug in it that
could cause an invalid scope to be generated when merging two
DILocations with no common ancestor scope.

This patch detects this situation and picks the scope of the first
location. This is not perfect, because the scope is misleading, but on
the other hand, this will be a line 0 location.

rdar://problem/43687474

Differential Revision: https://reviews.llvm.org/D51238

llvm-svn: 340672
2018-08-24 23:30:57 +00:00
David Blaikie
78e228c700 DebugInfo: Improve debug location merging
Fix a set of related bugs:

* Considering two locations as equivalent when their lines are the same
but their scopes are different causes erroneous debug info that
attributes a commoned call to be attributed to one of the two calls it
was commoned from.

* The previous code to compute a new location's scope was inaccurate and
would use the inlinedAt that was the /parent/ of the inlinedAt that is
the nearest common one, and also used that parent scope instead of the
nearest common scope.

* Not generating new locations generally seemed like a lower quality
choice

There was some risk that generating more new locations could hurt object
size by making more fine grained line table entries, but it looks like
that was offset by the decrease in line table (& address & ranges) size
caused by more accurately computing the scope - which likely lead to
fewer range entries (more contiguous ranges) & reduced size that way.

All up with these changes I saw minor reductions (-1.21%, -1.77%) in
.rela.debug_ranges and .rela.debug_addr (in a fission, compressed debug
info build) as well as other minor size changes (generally reductinos)
across the board (-1.32% debug_info.dwo, -1.28% debug_loc.dwo). Measured
in an optimized (-O2) build of the clang binary.

If you are investigating a size regression in an optimized debug builds,
this is certainly a patch to look into - and I'd be happy to look into
any major regressions found & see what we can do to address them.

llvm-svn: 340583
2018-08-23 22:35:58 +00:00
Alexey Bataev
bbf70ad02e [DEBUGINFO] Fix misprint in the name of DebugDirectivesOnly, NFC.
llvm-svn: 340553
2018-08-23 17:43:40 +00:00
David Blaikie
f435a2459a DebugInfo: Add metadata support for disabling DWARF pub sections
In cases where the debugger load time is a worthwhile tradeoff (or less
costly - such as loading from a DWP instead of a variety of DWOs
(possibly over a high-latency/distributed filesystem)) against object
file size, it can be reasonable to disable pubnames and corresponding
gdb-index creation in the linker.

A backend-flag version of this was implemented for NVPTX in
D44385/r327994 - which was fine for NVPTX which wouldn't mix-and-match
CUs. Now that it's going to be a user-facing option (likely powered by
"-gno-pubnames", the same as GCC) it should be encoded in the
DICompileUnit so it can vary per-CU.

After this, likely the NVPTX support should be migrated to the metadata
& the previous flag implementation should be removed.

Reviewers: aprantl

Differential Revision: https://reviews.llvm.org/D50213

llvm-svn: 339939
2018-08-16 21:29:55 +00:00
Adrian Prantl
d46169a911 [DebugInfoMetadata] Added DIFlags interface in DIBasicType.
Flags in DIBasicType will be used to pass attributes used in
DW_TAG_base_type, such as DW_AT_endianity.

Patch by Chirag Patel!

Differential Revision: https://reviews.llvm.org/D49610

llvm-svn: 339714
2018-08-14 19:35:34 +00:00
Alexey Bataev
95dd3b8ace [DEBUGINFO] Disable emission of the dwarf sections, but allow directives.
Summary:
Added an option that allows to emit only '.loc' and '.file' kind debug
directives, but disables emission of the DWARF sections. Required for
NVPTX target to support profiling. It requires '.loc' and '.file'
directives, but does not require any DWARF sections for the profiler.

Reviewers: probinson, echristo, dblaikie

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D46021

llvm-svn: 338616
2018-08-01 19:38:20 +00:00
Vedant Kumar
48bac26038 [DebugInfo] LowerDbgDeclare: Add derefs when handling CallInst users
LowerDbgDeclare inserts a dbg.value before each use of an address
described by a dbg.declare. When inserting a dbg.value before a CallInst
use, however, it fails to append DW_OP_deref to the DIExpression.

The DW_OP_deref is needed to reflect the fact that a dbg.value describes
a source variable directly (as opposed to a dbg.declare, which relies on
pointer indirection).

This patch adds in the DW_OP_deref where needed. This results in the
correct values being shown during a debug session for a program compiled
with ASan and optimizations (see https://reviews.llvm.org/D49520). Note
that ConvertDebugDeclareToDebugValue is already correct -- no changes
there were needed.

One complication is that SelectionDAG is unable to distinguish between
direct and indirect frame-index (FRAMEIX) SDDbgValues. This patch also
fixes this long-standing issue in order to not regress integration tests
relying on the incorrect assumption that all frame-index SDDbgValues are
indirect. This is a necessary fix: the newly-added DW_OP_derefs cannot
be lowered properly otherwise. Basically the fix prevents a direct
SDDbgValue with DIExpression(DW_OP_deref) from being dereferenced twice
by a debugger. There were a handful of tests relying on this incorrect
"FRAMEIX => indirect" assumption which actually had incorrect
DW_AT_locations: these are all fixed up in this patch.

Testing:

- check-llvm, and an end-to-end test using lldb to debug an optimized
  program.
- Existing unit tests for DIExpression::appendToStack fully cover the
  new DIExpression::append utility.
- check-debuginfo (the debug info integration tests)

Differential Revision: https://reviews.llvm.org/D49454

llvm-svn: 338069
2018-07-26 20:56:53 +00:00
Vedant Kumar
28a93dc229 Fix DIExpression::ExprOperand::appendToVector
appendToVector used the wrong overload of SmallVector::append, resulting
in it appending the same element to a vector `getSize()` times. This did
not cause a problem when initially committed because appendToVector was
only used to append 1-element operands.

This changes appendToVector to use the correct overload of append().

Testing: ./unittests/IR/IRTests --gtest_filter='*DIExpressionTest*'
llvm-svn: 336466
2018-07-06 21:06:21 +00:00
Vedant Kumar
0bce44c380 Remove a redundant null-check in DIExpression::prepend, NFC
Code outside of an `if (Expr)` block dereferenced `Expr`, so the null
check was redundant.

llvm-svn: 336465
2018-07-06 21:06:20 +00:00
Fangrui Song
02142d5985 [IR] Fix inconsistent declaration parameter name
llvm-svn: 336459
2018-07-06 19:26:00 +00:00
Vedant Kumar
7e4e253821 [Local] replaceAllDbgUsesWith: Update debug values before RAUW
The replaceAllDbgUsesWith utility helps passes preserve debug info when
replacing one value with another.

This improves upon the existing insertReplacementDbgValues API by:

- Updating debug intrinsics in-place, while preventing use-before-def of
  the replacement value.
- Falling back to salvageDebugInfo when a replacement can't be made.
- Moving the responsibiliy for rewriting llvm.dbg.* DIExpressions into
  common utility code.

Along with the API change, this teaches replaceAllDbgUsesWith how to
create DIExpressions for three basic integer and pointer conversions:

- The no-op conversion. Applies when the values have the same width, or
  have bit-for-bit compatible pointer representations.
- Truncation. Applies when the new value is wider than the old one.
- Zero/sign extension. Applies when the new value is narrower than the
  old one.

Testing:

- check-llvm, check-clang, a stage2 `-g -O3` build of clang,
  regression/unit testing.
- This resolves a number of mis-sized dbg.value diagnostics from
  Debugify.

Differential Revision: https://reviews.llvm.org/D48676

llvm-svn: 336451
2018-07-06 17:32:39 +00:00
Bjorn Pettersson
d6a0222d34 [IR] Strip trailing whitespace. NFC
llvm-svn: 336194
2018-07-03 12:39:52 +00:00
Bjorn Pettersson
b45e047d7d [DebugInfo] Corrections for salvageDebugInfo
Summary:
When salvaging a dbg.declare/dbg.addr we should not add
DW_OP_stack_value to the DIExpression
(see test/Transforms/InstCombine/salvage-dbg-declare.ll).

Consider this example
  %vla = alloca i32, i64 2
  call void @llvm.dbg.declare(metadata i32* %vla, metadata !1, metadata !DIExpression())

Instcombine will turn it into
  %vla1 = alloca [2 x i32]
  %vla1.sub = getelementptr inbounds [2 x i32], [2 x i32]* %vla, i64 0, i64 0
  call void @llvm.dbg.declare(metadata [2 x i32]* %vla1.sub, metadata !19, metadata !DIExpression())

If the GEP can be eliminated, then the dbg.declare will be salvaged
and we should get
  %vla1 = alloca [2 x i32]
  call void @llvm.dbg.declare(metadata [2 x i32]* %vla1, metadata !19, metadata !DIExpression())

The problem was that salvageDebugInfo did not recognize dbg.declare
as being indirect (%vla1 points to the value, it does not hold the
value), so we incorrectly got
  call void @llvm.dbg.declare(metadata [2 x i32]* %vla1, metadata !19, metadata !DIExpression(DW_OP_stack_value))

I also made sure that llvm::salvageDebugInfo and
DIExpression::prependOpcodes do not add DW_OP_stack_value to
the DIExpression in case no new operands are added to the
DIExpression. That way we avoid to, unneccessarily, turn a
register location expression into an implicit location expression
in some situations (see test11 in test/Transforms/LICM/sinking.ll).

Reviewers: aprantl, vsk

Reviewed By: aprantl, vsk

Subscribers: JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D48837

llvm-svn: 336191
2018-07-03 11:29:00 +00:00
Shiva Chen
a2029fa58e [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is

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

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

llvm.dbg.label(metadata !1)

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

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

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

Patch by Hsiangkai Wang.

llvm-svn: 331841
2018-05-09 02:40:45 +00:00
Bjorn Pettersson
67fede018f [DebugInfo] Correction for an assert in DIExpression::createFragmentExpression
Summary:
When we create a fragment expression, and there already is an
old fragment expression, we assert that the new fragment is
within the range for the old fragment.

If for example the old fragment expression says that we
describe bit 10-16 of a variable (Offset=10, Size=6),
and we now want to create a new fragment expression only
describing bit 3-6 of the original value, then the resulting
fragment expression should have Offset=13, Size=3.

The assert is supposed to catch if the resulting fragment
expression is outside the range for the old fragment. However,
it used to verify that the Offset+Size of the new fragment was
smaller or equal than Offset+Size for the old fragment. What
we really want to check is that Offset+Size of the new fragment
is smaller than the Size of the old fragment.

Reviewers: aprantl, vsk

Reviewed By: aprantl

Subscribers: davide, llvm-commits, JDevlieghere

Differential Revision: https://reviews.llvm.org/D46391

llvm-svn: 331465
2018-05-03 17:04:21 +00:00
Adrian Prantl
46c404a681 Fix a bug in GlobalOpt's handling of DIExpressions.
This patch adds support for fragment expressions
TryToShrinkGlobalToBoolean() which were previously just dropped.

Thanks to Reid Kleckner for providing me a reproducer!

llvm-svn: 331086
2018-04-27 21:41:36 +00:00
Vedant Kumar
5d0335a194 [DebugInfo] Create merged locations for instructions other than calls
This lifts a restriction on DILocation::getMergedLocation(), allowing it
to create merged locations for instructions other than calls.

Instruction::applyMergedLocation() now defaults to creating merged
locations for all instructions.

The default behavior of getMergedLocation() is unchanged: callers which
invoke it directly are unaffected.

This change will enable a follow-up Mem2Reg fix which improves crash
reporting.

Differential Revision: https://reviews.llvm.org/D45396

llvm-svn: 329955
2018-04-12 20:58:24 +00:00
Scott Linder
03316a5291 [DebugInfo] Support DWARF v5 source code embedding extension
In DWARF v5 the Line Number Program Header is extensible, allowing values with
new content types. In this extension a content type is added,
DW_LNCT_LLVM_source, which contains the embedded source code of the file.

Add new optional attribute for !DIFile IR metadata called source which contains
source text. Use this to output the source to the DWARF line table of code
objects. Analogously extend METADATA_FILE in Bitcode and .file directive in ASM
to support optional source.

Teach llvm-dwarfdump and llvm-objdump about the new values. Update the output
format of llvm-dwarfdump to make room for the new attribute on file_names
entries, and support embedded sources for the -source option in llvm-objdump.

Differential Revision: https://reviews.llvm.org/D42765

llvm-svn: 325970
2018-02-23 23:01:06 +00:00
Petar Jovanovic
f2a43da3d7 [Utils] Salvage the debug info of DCE'ed 'and' instructions
Preserve debug info from a dead 'and' instruction with a constant.

Patch by Djordje Todorovic.

Differential Revision: https://reviews.llvm.org/D43163

llvm-svn: 325119
2018-02-14 13:10:35 +00:00