Fixes the bug found by asan. Also XFAIL the new test for Darwin,
which is stuck on DWARF v2, and fix up other tests so they stop
failing on Windows.
llvm-svn: 326839
DWARF v5 specifies that the root file (also given in the DW_AT_name
attribute of the compilation unit DIE) should be emitted explicitly to
the line table's list of files. This makes the line table more
independent of the .debug_info section.
Differential Revision: https://reviews.llvm.org/D44054
llvm-svn: 326758
Summary:
Some targets does not support labels inside debug sections, but support
references in form `section +|- offset`. Patch adds initial support
for this. Also, this patch disables emission of all additional debug
sections that may have labels inside of it (like pub sections and
string tables).
Reviewers: probinson, echristo
Subscribers: JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D43627
llvm-svn: 326328
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
Summary:
If there is no debug info for macros, do not emit labels for empty
macinfo sections.
Reviewers: probinson, echristo
Subscribers: aprantl, llvm-commits, JDevlieghere
Differential Revision: https://reviews.llvm.org/D43589
llvm-svn: 325803
Summary:
This commit separates the abstract accelerator table data structure
from the code for writing out an on-disk representation of a specific
accelerator table format. The idea is that former (now called
AccelTable<T>) can be reused for the DWARF v5 accelerator tables
as-is, without any further customizations.
Some bits of the emission code (now living in the EmissionContext class)
can be reused for DWARF v5 as well, but the subtle differences in the
layout of various subtables mean the sharing is not always possible.
(Also, the individual emit*** functions are fairly simple so there's a
tradeoff between making a bigger general-purpose function, and two
smaller targeted functions.)
Another advantage of this setup is that more of the serialization logic
can be hidden in the .cpp file -- I have moved declarations of the
header and all the emission functions there.
Reviewers: JDevlieghere, aprantl, probinson, dblaikie
Subscribers: echristo, clayborg, vleschuk, llvm-commits
Differential Revision: https://reviews.llvm.org/D43285
llvm-svn: 325516
The prologue-end line record must be emitted after the last
instruction that is part of the function frame setup code and before
the instruction that marks the beginning of the function body.
Patch by Carlos Alberto Enciso!
Differential Revision: https://reviews.llvm.org/D41762
llvm-svn: 325143
This patch renames DwarfAccelTable.{h,cpp} to AccelTable.{h,cpp} and
moves the header to the include dir so it is accessible by the
dsymutil implementation.
Differential revision: https://reviews.llvm.org/D42529
llvm-svn: 323654
This patch refactors the way data is stored in the accelerator table and
makes them truly generic. There have been several attempts to do this in
the past:
- D8215 & D8216: Using a union and partial hardcoding.
- D11805: Using inheritance.
- D42246: Using a callback.
In the end I didn't like either of them, because for some reason or
another parts of it felt hacky or decreased runtime performance. I
didn't want to completely rewrite them as I was hoping that we could
reuse parts for the successor in the DWARF standard. However, it seems
less and less likely that there will be a lot of opportunities for
sharing code and/or an interface.
Originally I choose to template the whole class, because it introduces
no performance overhead compared to the original implementation.
We ended up settling on a hybrid between a templated method and a
virtual call to emit the data. The motivation is that we don't want to
increase code size for a feature that should soon be superseded by the
DWARFv5 accelerator tables. While the code will continue to be used for
compatibility, it won't be on the hot path. Furthermore this does not
regress performance compared to Apple's internal implementation that
already uses virtual calls for this.
A quick summary for why these changes are necessary: dsymutil likes to
reuse the current implementation of the Apple accelerator tables.
However, LLDB expects a slightly different interface than what is
currently emitted. Additionally, in dsymutil we only have offsets and no
actual DIEs.
Although the patch suggests a lot of code has changed, this change is
pretty straightforward:
- We created an abstract class `AppleAccelTableData` to serve as an
interface for the different data classes.
- We created two implementations of this class, one for type tables and
one for everything else. There will be a third one for dsymutil that
takes just the offset.
- We use the supplied class to deduct the atoms for the header which
makes the structure of the table fully self contained, although not
enforced by the interface as was the case for the fully templated
approach.
- We renamed the prefix from DWARF- to Apple- to make space for the
future implementation of .debug_names.
This change is NFC and relies on the existing tests.
Differential revision: https://reviews.llvm.org/D42334
llvm-svn: 323653
Summary: This is the producer side for DWARF v5 string offsets tables. The reader/consumer
side was committed with r321295. All compile and type units in a module share a
contribution to the string offsets table. Indirect strings use the strx{1,2,3,4} index forms.
Reviewers: dblaikie, aprantl, JDevliegehere
Differential Revision: https://reviews.llvm.org/D42021
llvm-svn: 323546
Summary:
Currently -glldb turns on emission of apple tables on all targets, but
lldb is only really capable of consuming them on darwin. Furthermore,
making lldb consume these tables is not straight-forward because of the
differences in how the debug info is distributed on darwin vs. elf
targets.
The darwin debug model assumes that the debug info (along with
accelerator tables) will either remain in the .o files or it will be
linked into a dsym bundle by a linker that knows how to merge these
tables. In the elf world, all present linkers will simply concatenate
these accelerator tables into the shared object. Since the tables are
not self-terminating, this renders the tables unusable, as the debugger
cannot pry the individual tables apart anymore.
It might theoretically be possible to make the tables work with split
dwarf, as that is somewhat similar to the apple .o model, but
unfortunately right now the combination of -glldb and -gsplit-dwarf
produces broken object files.
Until these issues are resolved there is no point in emitting the apple
tables for these targets. At best, it wastes space; at worst, it breaks
compilation and prevents the user from getting other benefits of -glldb.
Reviewers: probinson, aprantl, dblaikie
Subscribers: emaste, dim, llvm-commits, JDevlieghere
Differential Revision: https://reviews.llvm.org/D41986
llvm-svn: 322633
Pass MD5 checksums through from IR to assembly/object files.
After this, getting Clang to compute the MD5 should be the last step
to supporting MD5 in the DWARF v5 line table header.
Differential Revision: https://reviews.llvm.org/D41926
llvm-svn: 322391
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
The comparator passed to std::sort must provide a strict weak ordering;
otherwise, the behavior is undefined.
Fixes an assertion failure generating debug info for globals
split by GlobalOpt. I have a testcase, but not sure how to reduce it,
so not included here. (Someone else came up with a testcase, but I
can't reproduce the crash with it, presumably because my version of LLVM
ends up sorting the array differently.)
This isn't really a complete fix (see the FIXME in the patch), but at
least it doesn't have undefined behavior.
Differential Revision: https://reviews.llvm.org/D38830
llvm-svn: 315619
While this shouldn't be necessary anymore, we have cases where we run
into the assertion below, i.e. cases with two non-fragment entries for the
same variable at different frame indices.
This should be fixed, but for now, we should revert to a version that
does not trigger asserts.
llvm-svn: 315576
Some passes might duplicate calls to llvm.dbg.declare creating
duplicate frame index expression which currently trigger an assertion
which is meant to catch erroneous, overlapping fragment declarations.
But identical frame index expressions are just redundant and don't
actually conflict with each other, so we can be more lenient and just
ignore the duplicates.
Reviewers: aprantl, rnk
Subscribers: llvm-commits, JDevlieghere
Differential Revision: https://reviews.llvm.org/D38540
llvm-svn: 315279
A prologue-end line record is emitted with an incorrect associated address,
which causes a debugger to show the beginning of function body to be inside
the prologue.
Patch written by Carlos Alberto Enciso.
Differential Revision: https://reviews.llvm.org/D37625
llvm-svn: 313047
They won't affect the DWARF output, but they will mess with the
sorting of the fragments. This fixes the crash reported in PR34159.
https://bugs.llvm.org/show_bug.cgi?id=34159
llvm-svn: 311217
Chromium's gold build seems to have trouble with this (gold produces
errors) - not sure if it's gold that's not coping with the valid
representation, or a bug in the implementation in LLVM, etc.
llvm-svn: 309630
Missed the resetting base address selections when going from a base
address version to zero base address for non-base-addressed entries.
llvm-svn: 309529
(from comments in the test)
Group ranges in a range list that apply to the same section and use a base
address selection entry to reduce the number of relocations to one reloc per
section per range list. DWARF5 debug_rnglist will be more efficient than this
in terms of relocations, but it's still better than one reloc per entry in a
range list.
This is an object/executable size tradeoff - shrinking objects, but growing
the linked executable. In one large binary tested, total object size (not just
debug info) shrank by 16%, entirely relocation entries. Linked executable
grew by 4%. This was with compressed debug info in the objects, uncompressed
in the linked executable. Without compression in the objects, the win would be
smaller (the growth of debug_ranges itself would be more significant).
llvm-svn: 309526
This can come up in ThinLTO & wastes space & makes degenerate IR.
As per the added FIXME, ultimately, local imported entities should hang
off the function and that way the imported entity list on the CU can be
tested for emptiness like all the other CU lists.
(function-attached local imported entities are probably also the best
path forward for fixing how imported entities are handled both in
cross-module use (currently, while ThinLTO preserves the imported
entities, they would not get used at the imported inlined location -
only in the abstract origin that appears in the partial CU created by
the import (which isn't emitted under Fission due to cross-CU
limitations there)) and to reduce the number of points where imported
entities are emitted (they're currently emitted into every inlined
instance, concrete instance, and abstract origin - they should only go
in teh abstract origin if there is one, otherwise in the concrete
instance - but this requires lots of delayed handling and wiring up,
same as abstract variables & subprograms))
llvm-svn: 309354
Local imported entities at the top level of a subprogram were being
handled differently from those in nested scopes - that different
handling would cause pseudo concrete out-of-line definitions to be
created (but without any of their attributes, nor an abstract_origin) in
the case where there was no real concrete definition.
These local imported entities also only appeared in the concrete
definition where those imported entities in nested scopes appear in all
cases (abstract, concrete, and inlined). This change at least makes top
level case handle the same as the others - though there's a FIXME to
improve this to /only/ emit them into the abstract origin (though this
requires more plumbing - like the abstract subprogram and variable
handling that must defer population until the end of the unit to
discover if there is an abstract origin, or only a standalone concrete
definition).
llvm-svn: 309237
This is a better fix than r308708 for the problem introduced in
r304020. It restores the skeleton CU testcases modified by that commit
to their original form and most importantly ensures that
frontend-generated skeleton CUs (such as used to point to Clang
modules) come after the regular CUs. This broke for DICompileUnit
nodes that don't have any immediate children because they are now
constructed lazily instead of the order in which they are listed in
!llvm.dbg.cu. After this commit we still don't guarantee that order,
but we do guarantee that empty skeletons come last.
Shipping versions of LLDB are very sensitive to the ordering of
CUs. I'll track a fix for LLDB to be more permissive separately.
This fixes a test failure in the LLDB testsuite.
rdar://problem/33357252
llvm-svn: 309154
The instruction it falls over on is an IMPLICT_DEF that also happens
to be the only instruction in its lexical scope. That LexicalScope has
never been created because its range is empty. This patch skips over
all meta-instructions instead of just DBG_VALUEs.
Thanks to David Blaikie for providing a testcase!
llvm-svn: 305853
For the following motivating example
bool c();
void f();
bool start() {
bool result = c();
if (!c()) {
result = false;
goto exit;
}
f();
result = true;
exit:
return result;
}
we would previously generate a single DW_AT_const_value(1) because
only the DBG_VALUE in the second-to-last basic block survived
codegen. This patch improves the heuristic used to determine when a
DBG_VALUE is available at the beginning of its variable's enclosing
lexical scope:
- Stop giving singular constants blanket permission to take over the
entire scope. There is still a special case for constants in the
function prologue that we also miight want to retire later.
- Use the lexical scope information to determine available-at-entry
instead of proximity to the function prologue.
After this patch we generate a location list with a more accurate
narrower availability for the constant true value. As a pleasant side
effect, we also generate inline locations instead of location lists
where a loacation covers the entire range of the enclosing lexical
scope.
Measured on compiling llc with four targets this doesn't have an
effect on compile time and reduces the size of the debug info for llc
by ~600K.
rdar://problem/30286912
llvm-svn: 305599
Summary:
This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things.
The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack.
This is done in three stages:
• The first patch (LLVM) adds support for DW_OP_plus_uconst.
• The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst.
• The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions.
Patch by Sander de Smalen.
Reviewers: echristo, pcc, aprantl
Reviewed By: aprantl
Subscribers: fhahn, javed.absar, aprantl, llvm-commits
Differential Revision: https://reviews.llvm.org/D33894
llvm-svn: 305386
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
This is really a workaround for ThinLTO in particular - since it can
import partial CUs that may end up looking very similar/the same as
the same partial import in another ThinLTO compile.
An alternative fix would be to change the DICompileUnit metadata to
include a "primary file" or the like - and when importing for ThinLTO
set the primary file to the name of the DICompileUnit that is being
imported into. This involves changing the schema and would reduce the
excessive uniqueness in the hash that this change creates - allowing
diagnosing of more duplicate CUs than will be caught with this change.
But duplicate CUs can still be caught in non-ThinLTO builds & are mostly
a nuisance rather than a particularly deliberate/effective tool for
finding broken code. (arguably the hash could always include the dwo
file and nothing in fission would break, I think..)
Reapply of r304119 after adding a triple to the test and moving it
to the X86 directory.
llvm-svn: 304130
When the only use of a CU is for a subprogram that's only emitted into
the using CU (to avoid cross-CU references in DWO files), avoid creating
that CU at all.
Reapply of r304111 after adding a triple to the test and moving it
to the X86 directory.
llvm-svn: 304129
This is really a workaround for ThinLTO in particular - since it can
import partial CUs that may end up looking very similar/the same as
the same partial import in another ThinLTO compile.
An alternative fix would be to change the DICompileUnit metadata to
include a "primary file" or the like - and when importing for ThinLTO
set the primary file to the name of the DICompileUnit that is being
imported into. This involves changing the schema and would reduce the
excessive uniqueness in the hash that this change creates - allowing
diagnosing of more duplicate CUs than will be caught with this change.
But duplicate CUs can still be caught in non-ThinLTO builds & are mostly
a nuisance rather than a particularly deliberate/effective tool for
finding broken code. (arguably the hash could always include the dwo
file and nothing in fission would break, I think..)
llvm-svn: 304119
When the only use of a CU is for a subprogram that's only emitted into
the using CU (to avoid cross-CU references in DWO files), avoid creating
that CU at all.
llvm-svn: 304111
Consistent with GCC and addresses a shortcoming with ThinLTO where many
imported CUs may end up being empty (because the functions imported from
them either ended up not being used (and were then discarded, since
they're imported as available_externally) or optimized away entirely).
Test cases previously testing empty CUs (either intentionally, or
because they didn't need anything more complicated) had a trivial 'int'
or similar basic type added to their retained types list.
This is a first order approximation - a deeper implementation could do
things like:
1) Be more lazy about construction of the CU - for example if two CUs
containing a single identical retained type are linked together, with
this change one of the two CUs will be produced but empty (since a
duplicate type won't be produced).
2) Go further and invert all the CU links the same way the subprogram
link is inverted - keep named CU lists of retained types, macros, etc,
and have those link back to the CU. Then if they're emitted, the CU is
emitted, but never otherwise - this would allow the metadata itself to
be dropped earlier too, though it seems unlikely that's an important
optimization as there shouldn't be many CUs relative to the number of
other entities.
llvm-svn: 304020
This produced 'strange' DWARF anyway - the CU would have no ranges (or
at least not a range including the inlined code) nor any subprogram or
inlined_subroutine - yet the line table would have entries for these
instructions.
(this actually becomes more relevant with changes coming after this,
where a CU without any contents will be omitted entirely - so there
would be no line table to put this on anyway)
llvm-svn: 304004
Previously this code was defensive to the situation in which the debug
info scopes would lead to a different subprogram from the subprogram in
the CU's subprogram list (this could've happened with linkonce
functions, etc as per the comment being removed). Since the CU<>SP link
reversal this is no longer possible.
llvm-svn: 303933
Turns out gold doesn't use the DW_AT_GNU_pubnames to decide whether to
parse the rest of the DIEs when building gdb-index. This causes gold to
trip over LLVM's output when there are DW_FORM_ref_addr present.
Gold does use the presence of a debug_gnu_pub{names,types} entry for the
CU to skip parsing the debug_info portion, so make sure that's included
even when empty (technically, when empty there couldn't be any ref_addr
anyway - it only came up when gmlt didn't produce any (even non-empty)
pubnames - but given what that reveals about gold's implementation, this
seems like a good thing to do for consistency).
llvm-svn: 303894
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
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
Turns out that the Fission/Split DWARF package format (DWP) is currently
insufficient to handle cross-CU (ref_addr) references. So for now,
duplicate any debug info needed in these situations:
* inlined_subroutine's abstract_origin
* inlined variable's abstract_origin
* types
Keep the ref_addr behavior in general, including in the split DWARF
inline debug info that can be emitted into the object files for online
symbolication.
Keep a flag to use the old (ref_addr) behavior for testing ways of
addressing this limitation in the DWP tool (& for those not using DWP
packaging).
llvm-svn: 302858
Since Split DWARF needs to name the actual .dwo file that is generated,
it can't be known at the time the llvm::Module is produced as it may be
merged with other Modules before the object is generated and that object
may be generated with any name.
By passing the Split DWARF file name when LLVM is producing object code
the .dwo file name in the object file can match correctly.
The support for Split DWARF for implicit modules remains the same -
using metadata to store the dwo name and dwo id so that potentially
multiple skeleton CUs referring to different dwo files can be generated
from one llvm::Module.
llvm-svn: 301062
- introduced in r300522 and found via the Swift LLDB testsuite.
The fix is to set the location kind to memory whenever an FrameIndex
location is emitted.
rdar://problem/31707602
llvm-svn: 300793
- introduced in r300522 and found via the Swift LLDB testsuite.
The fix is to set the location kind to memory whenever an FrameIndex
location is emitted.
rdar://problem/31707602
llvm-svn: 300790
The DWARF specification knows 3 kinds of non-empty simple location
descriptions:
1. Register location descriptions
- describe a variable in a register
- consist of only a DW_OP_reg
2. Memory location descriptions
- describe the address of a variable
3. Implicit location descriptions
- describe the value of a variable
- end with DW_OP_stack_value & friends
The existing DwarfExpression code is pretty much ignorant of these
restrictions. This used to not matter because we only emitted very
short expressions that we happened to get right by accident. This
patch makes DwarfExpression aware of the rules defined by the DWARF
standard and now chooses the right kind of location description for
each expression being emitted.
This would have been an NFC commit (for the existing testsuite) if not
for the way that clang describes captured block variables. Based on
how the previous code in LLVM emitted locations, DW_OP_deref
operations that should have come at the end of the expression are put
at its beginning. Fixing this means changing the semantics of
DIExpression, so this patch bumps the version number of DIExpression
and implements a bitcode upgrade.
There are two major changes in this patch:
I had to fix the semantics of dbg.declare for describing function
arguments. After this patch a dbg.declare always takes the *address*
of a variable as the first argument, even if the argument is not an
alloca.
When lowering a DBG_VALUE, the decision of whether to emit a register
location description or a memory location description depends on the
MachineLocation — register machine locations may get promoted to
memory locations based on their DIExpression. (Future) optimization
passes that want to salvage implicit debug location for variables may
do so by appending a DW_OP_stack_value. For example:
DBG_VALUE, [RBP-8] --> DW_OP_fbreg -8
DBG_VALUE, RAX --> DW_OP_reg0 +0
DBG_VALUE, RAX, DIExpression(DW_OP_deref) --> DW_OP_reg0 +0
All testcases that were modified were regenerated from clang. I also
added source-based testcases for each of these to the debuginfo-tests
repository over the last week to make sure that no synchronized bugs
slip in. The debuginfo-tests compile from source and run the debugger.
https://bugs.llvm.org/show_bug.cgi?id=32382
<rdar://problem/31205000>
Differential Revision: https://reviews.llvm.org/D31439
llvm-svn: 300522
Also add an assertion for the case that there are multiple FI
expressions with a DW_OP_LLVM_fragment; which should violate internal
constraints in DbgVariable.
llvm-svn: 298518
In doing so, clean up the MD5 interface a little. Most
existing users only care about the lower 8 bytes of an MD5,
but for some users that care about the upper and lower,
there wasn't a good interface. Furthermore, consumers
of the MD5 checksum were required to handle endianness
details on their own, so it seems reasonable to abstract
this into a nicer interface that just gives you the right
value.
Differential Revision: https://reviews.llvm.org/D31105
llvm-svn: 298322
and mark the methods as protected.
Besides reducing the surface area of DwarfExpression, this is in
preparation for an upcoming bugfix in the DwarfExpression
implementation, for which it will be necessary to defer emitting
register operations until the rest of the expression is known.
NFC
llvm-svn: 298309
This reverts commit r242302. External type refs of this form were
never used by any LLVM frontend so this is effectively dead code.
(They were introduced to support clang module debug info, but in the
end we came up with a better design that doesn't use this feature at
all.)
rdar://problem/25897929
Differential Revision: https://reviews.llvm.org/D30917
llvm-svn: 297684
This fixes PR31381, which caused an assertion and/or invalid debug info.
This affects debug variables that have multiple fragments in the MMI
side (i.e.: in the stack frame) table.
rdar://problem/30571676
llvm-svn: 295486
While looking to add support for placing singular types (types that will
only be emitted in one place (such as attached to a strong vtable or
explicit template instantiation definition)) not in type units (since
type units have overhead) I stumbled across that change causing an
increase in pubtypes.
Turns out we were missing some types from type units if they were only
referenced from other type units and not from the debug_info section.
This fixes that, following GCC's line of describing the offset of such
entities as the CU die (since there's no compile unit-relative offset
that would describe such an entity - they aren't in the CU). Also like
GCC, this change prefers to describe the type stub within the CU rather
than the "just use the CU offset" fallback where possible. This may give
the DWARF consumer some opportunity to find the extra info in the type
stub - though I'm not sure GDB does anything with this currently.
The size of the pubnames/pubtypes sections now match exactly with or
without type units enabled.
This nearly triples (+189%) the pubtypes section for a clang self-host
and grows pubnames by 0.07% (without compression). For a total of 8%
increase in debug info sections of the objects of a Split DWARF build
when using type units.
llvm-svn: 293971
LTO. Replace it with a related assertion, ensuring that abstract
variables appear only in abstract scopes.
Part of PR31437.
Differential Revision: http://reviews.llvm.org/D29430
llvm-svn: 293841
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
This reapplies r289902 with additional testcase upgrades and a change
to the Bitcode record for DIGlobalVariable, that makes upgrading the
old format unambiguous also for variables without DIExpressions.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
llvm-svn: 290153
This reverts commit 289920 (again).
I forgot to implement a Bitcode upgrade for the case where a DIGlobalVariable
has not DIExpression. Unfortunately it is not possible to safely upgrade
these variables without adding a flag to the bitcode record indicating which
version they are.
My plan of record is to roll the planned follow-up patch that adds a
unit: field to DIGlobalVariable into this patch before recomitting.
This way we only need one Bitcode upgrade for both changes (with a
version flag in the bitcode record to safely distinguish the record
formats).
Sorry for the churn!
llvm-svn: 289982
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
This reapplies r289902 with additional testcase upgrades.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
llvm-svn: 289920
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
llvm-svn: 289902
Follow-up to r289256, address a FIXME to avoid resetting the column
number. This reduced .debug_line by 2.6% in a RelWithDebInfo
self-build of clang.
llvm-svn: 289620
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
LLVM's use of DW_OP_bit_piece is incorrect and a based on a
misunderstanding of the wording in the DWARF specification. The offset
argument of DW_OP_bit_piece refers to the offset into the location
that is on the top of the DWARF expression stack, and not an offset
into the source variable. This has since also been clarified in the
DWARF specification.
This patch fixes all uses of DW_OP_bit_piece to emit the correct
offset and simplifies the DwarfExpression class to semi-automaticaly
emit empty DW_OP_pieces to adjust the offset of the source variable,
thus simplifying the code using DwarfExpression.
While this is an incompatible bugfix, in practice I don't expect this
to be much of a problem since LLVM's old interpretation and the
correct interpretation of DW_OP_bit_piece differ only when there are
gaps in the fragmented locations of the described variables or if
individual fragments are smaller than a byte. LLDB at least won't
interpret locations with gaps in them because is has no way to present
undefined bits in a variable, and there is a high probability that an
old-form expression will be malformed when interpreted correctly,
because the DW_OP_bit_piece offset will be outside of the location at
the top of the stack.
As a nice side-effect, this patch enables us to use a more efficient
encoding for subregisters: In order to express a sub-register at a
non-zero offset we now use a DW_OP_bit_piece instead of shifting the
value into place manually.
This patch also adds missing test coverage for code paths that weren't
exercised before.
<rdar://problem/29335809>
Differential Revision: https://reviews.llvm.org/D27550
llvm-svn: 289266
Like DBG_VALUE, these emit nothing to the .text section, and sometimes
have no source location specified. Just ignore them.
Differential Revision: http://reviews.llvm.org/D27492
llvm-svn: 289256
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
The DIEUnit class represents a compile or type unit and it owns the unit DIE as an instance variable. This allows anyone with a DIE, to get the unit DIE, and then get back to its DIEUnit without adding any new ivars to the DIE class. Why was this needed? The DIE class has an Offset that is always the CU relative DIE offset, not the "offset in debug info section" as was commented in the header file (the comment has been corrected). This is great for performance because most DIE references are compile unit relative and this means most code that accessed the DIE's offset didn't need to make it into a compile unit relative offset because it already was. When we needed to emit a DW_FORM_ref_addr though, we needed to find the absolute offset of the DIE by finding the DIE's compile/type unit. This class did have the absolute debug info/type offset and could be added to the CU relative offset to compute the absolute offset. With this change we can easily get back to a DIE's DIEUnit which will have this needed offset. Prior to this is required having a DwarfDebug and required calling:
DwarfCompileUnit *DwarfDebug::lookupUnit(const DIE *CU) const;
Now we can use the DIEUnit class to do so without needing DwarfDebug. All clients now use DIEUnit objects (the DwarfDebug stack and the DwarfLinker). A follow on patch for the DWARF generator will also take advantage of this.
Differential Revision: https://reviews.llvm.org/D27170
llvm-svn: 288399
Paul Robinson