Along with a test case to demonstrate that due to inlining order there
are cases where abstract variable DIEs are not constructed since the
abstract subprogram was built due to a previous inlining that optimized
away those variables. This produces incorrect debug info (the 'missing'
abstract variable causes the inlined instance of that variable to be
emitted with a full description (name, line, file) rather than
referencing the abstract origin), but this commit at least ensures that
it doesn't crash...
llvm-svn: 210143
This patch changes GlobalAlias to point to an arbitrary ConstantExpr and it is
up to MC (or the system assembler) to decide if that expression is valid or not.
This reduces our ability to diagnose invalid uses and how early we can spot
them, but it also lets us do things like
@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
i32 ptrtoint (i32* @bar to i32)) to i32*)
An important implication of this patch is that the notion of aliased global
doesn't exist any more. The alias has to encode the information needed to
access it in its metadata (linkage, visibility, type, etc).
Another consequence to notice is that getSection has to return a "const char *".
It could return a NullTerminatedStringRef if there was such a thing, but when
that was proposed the decision was to just uses "const char*" for that.
llvm-svn: 210062
This was previously committed in r209680 and reverted in r209683 after
it caused sanitizer builds to crash.
The issue seems to be that the DebugLoc associated with dbg.value IR
intrinsics isn't necessarily accurate. Instead, we duplicate the
DIVariables and add an InlinedAt field to them to record their
location.
We were using this InlinedAt field to compute the LexicalScope for the
variable, but not using it in the abstract DbgVariable construction and
mapping. This resulted in a formal parameter to the current concrete
function, correctly having no InlinedAt information, but incorrectly
having a DebugLoc that described an inlined location within the
function... thus an abstract DbgVariable was created for the variable,
but its DIE was never constructed (since the LexicalScope had no such
variable). This DbgVariable was silently ignored (by testing for a
non-null DIE on the abstract DbgVariable).
So, fix this by using the right scoping information when constructing
abstract DbgVariables.
In the long run, I suspect we want to undo the work that added this
second kind of location tracking and fix the places where the DebugLoc
propagation on the dbg.value intrinsic fails. This will shrink debug
info (by not duplicating DIVariables), make it more efficient (by not
having to construct new DIVariable metadata nodes to try to map back to
a single variable), and benefit all instructions.
But perhaps there are insurmountable issues with DebugLoc quality that
I'm unaware of... I just don't know how we can't /just keep the DebugLoc
from the dbg.declare to the dbg.values and never get this wrong/.
Some history context:
http://llvm.org/viewvc/llvm-project?view=revision&revision=135629http://llvm.org/viewvc/llvm-project?view=revision&revision=137253
llvm-svn: 209984
For MIPS, we have to encode the personality routine with
an indirect pointer to absptr; otherwise, some link warning
warning will be raised, and the program might crash in some
early MIPS Android device.
llvm-svn: 209907
Use more straightforward way to represent the set of instruction
ranges where the location of a user variable is defined - vector of pairs
of instructions (defining start/end of each range),
instead of a flattened vector of instructions where some instructions
are supposed to start the range, and the rest are supposed to "clobber" it.
Simplify the code which generates actual .debug_loc entries.
No functionality change.
llvm-svn: 209698
Current implementation of calculateDbgValueHistory already creates the
keys in the expected order (user variables are listed in order of appearance),
and should do so later by contract.
No functionality change.
llvm-svn: 209690
I'm not sure exactly where/how we end up with an abstract DbgVariable
with a null DIE, but we do... looking into it & will add a test and/or
fix when I figure it out.
Currently shows up in selfhost or compiler-rt builds.
llvm-svn: 209683
After much puppetry, here's the major piece of the work to ensure that
even when a concrete definition preceeds all inline definitions, an
abstract definition is still created and referenced from both concrete
and inline definitions.
Variables are still broken in this case (see comment in
dbg-value-inlined-parameter.ll test case) and will be addressed in
follow up work.
llvm-svn: 209677
A further step to correctly emitting concrete out of line definitions
preceeding inlined instances of the same program.
To do this, emission of subprograms must be delayed until required since
we don't know which (abstract only (if there's no out of line
definition), concrete only (if there are no inlined instances), or both)
DIEs are required at the start of the module.
To reduce the test churn in the following commit that actually fixes the
bug, this commit introduces the lazy DIE construction and cleans up test
cases that are impacted by the changes in the resulting DIE ordering.
llvm-svn: 209675
This is a precursor to fixing inlined debug info where the concrete,
out-of-line definition may preceed any inlined usage. To cope with this,
the attributes that may appear on the concrete definition or the
abstract definition are delayed until the end of the module. Then, if an
abstract definition was created, it is referenced (and no other
attributes are added to the out-of-line definition), otherwise the
attributes are added directly to the out-of-line definition.
In a couple of cases this causes not just reordering of attributes, but
reordering of types. When the creation of the attribute is delayed, if
that creation would create a type (such as for a DW_AT_type attribute)
then other top level DIEs may've been constructed during the delay,
causing the referenced type to be created and added after those
intervening DIEs. In the extreme case, in cross-cu-inlining.ll, this
actually causes the DW_TAG_basic_type for "int" to move from one CU to
another.
llvm-svn: 209674
This seems like a simple cleanup/improved consistency, but also helps
lay the foundation to fix the bug mentioned in the test case: concrete
definitions preceeding any inlined usage aren't properly split into
concrete + abstract (because they're not known to need it until it's too
late).
Once we start deferring this choice until later, we won't have the
choice to put concrete definitions for inlined subroutines in a
different scope from concrete definitions for non-inlined subroutines
(since we won't know at time-of-construction which one it'll be). This
change brings those two cases into alignment ahead of that future
chaneg/fix.
llvm-svn: 209547
It's not really a "ScopeDIE", as such - it's the abstract function
definition's DIE. And we usually use "SP" for subprograms, rather than
"Sub".
llvm-svn: 209499
constructSubprogramDIE was already called for every subprogram in every
CU when the module was started - there's no need to call it again at
module finalization.
llvm-svn: 209372
This reverts commit r208930, r208933, and r208975.
It seems not all fission consumers are ready to handle this behavior.
Reverting until tools are brought up to spec.
llvm-svn: 209338
Committed in r209178 then reverted in r209251 due to LTO breakage,
here's a proper fix for the case of the missing subprogram DIE. The DIEs
were there, just in other compile units. Using the SPMap we can find the
right compile unit to search for and produce cross-unit references to
describe this kind of inlining.
One existing test case needed to be updated because it had a function
that wasn't in the CU's subprogram list, so it didn't appear in the
SPMap.
llvm-svn: 209335
This reverts commit r209178.
This seems to be asserting in an LTO build on some internal Apple
buildbots. No upstream reproduction (and I don't have an LLVM-aware gold
built right now to reproduce it personally) but it's a small patch & the
failure's semi-plausible so I'm going to revert first while I try to
reproduce this.
llvm-svn: 209251
Undecided whether this should include a test case - SROA produces bad
dbg.value metadata describing a value for a reference that is actually
the value of the thing the reference refers to. For now, loosening the
assert lets this not assert, but it's still bogus/wrong output...
If someone wants to tell me to add a test, I'm willing/able, just
undecided. Hopefully we'll get SROA fixed soon & we can tighten up this
assertion again.
llvm-svn: 209240
This change preserves the original algorithm of generating history
for user variables, but makes it more clear.
High-level description of algorithm:
Scan all the machine basic blocks and machine instructions in the order
they are emitted to the object file. Do the following:
1) If we see a DBG_VALUE instruction, add it to the history of the
corresponding user variable. Keep track of all user variables, whose
locations are described by a register.
2) If we see a regular instruction, look at all the registers it clobbers,
and terminate the location range for all variables described by these registers.
3) At the end of the basic block, terminate location ranges for all
user variables described by some register.
Although this change shouldn't be user-visible (the contents of .debug_loc section
should be the same), it changes some internal assumptions about the set
of instructions used to track the variable locations. Watching the bots.
llvm-svn: 209225
In refactoring DwarfUnit::isUnsignedDIType I restricted it to only work
on values with signedness (unsigned or signed), asserting on anything
else (which did uncover some bugs). But it turns out that we do need to
emit constants of signless data, such as pointer constants - only null
pointer constants are known to need this so far, but it's conceivable
that there might be non-null pointer constants at some point (hardcoded
address offsets for device drivers?).
This patch just uses 'unsigned' for signless data such as pointer
constants. Arguably we could use signless representations
(DW_FORM_dataN) instead, allowing a trinary result from isUnsignedDIType
(signed, unsigned, signless), but this seems reasonable for now.
llvm-svn: 209223
This workaround (presumably for ancient GDB) doesn't appear to be
required (GDB 7.5 seems to tolerate function definition DIEs in
namespace scope just fine).
llvm-svn: 209189
Since we visit the whole list of subprograms for each CU at module
start, this is clearly true - don't test for the case, just assert it.
A few old test cases seemed to have incomplete subprogram lists, but any
attempt to reproduce them shows full subprogram lists that even include
entities that have been completely inlined and the out of line
definition removed.
llvm-svn: 209178
When I refactored this in r208636 I accidentally caused this to be added
multiple times to each abstract subprogram (not accounting for the
deduplicating effect of the InlinedSubprogramDIEs set).
This got better in r208798 when the abstract definitions got the
attribute added to them at construction time, but still had the
redundant copies introduced in r208636.
This commit removes those excess DW_AT_inlines and relies solely on the
insertion in r208798.
llvm-svn: 209166
The check in DwarfDebug::constructScopeDIE was meant to consider inlined
subroutines as any non-top-level scope that was a subprogram. Instead of
checking "not top level scope" it was checking if the /subprogram's/
scope was non-top-level.
Fix this and beef up a test case to demonstrate some of the missing
inlined_subroutines are no longer missing.
In the course of fixing this I also found that r208748 (with this fix)
found one /extra/ inlined_subroutine in concrete_out_of_line.ll due to
two inlined_subroutines having the same inlinedAt location. The previous
implementation was collapsing these into a single inlined subroutine.
I'm not sure what the original code was that created this .ll file so
I'm not sure if this actually happens in practice today. Since we
deliberately include column information to disambiguate two calls on the
same line, that may've addressed this bug in the frontend, but it's good
to know that workaround isn't necessary for this particular case
anymore.
llvm-svn: 209165
This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized. This is necessary for MSVC
ABI compatibility. Once we have comdats for guard variables, we can use
the combination to help GlobalOpt fire more often for weak data with
guarded initialization on other platforms.
Reviewers: nlewycky
Differential Revision: http://reviews.llvm.org/D3499
llvm-svn: 209015
I'm not sure this is how it'll be going forward (I'd rather prefer the
definition to be in the main SP mapping, for various reasons) but this
helps me understand how it is today.
llvm-svn: 209009
DIBuilder maintains this invariant and the current DwarfDebug code could
end up doing weird things if it contained declarations (such as putting
the definition DIE inside a CU that contained the declaration - this
doesn't seem like a good idea, so rather than adding logic to handle
this case we'll just ban in for now & cross that bridge if we come to
it later).
llvm-svn: 209004
This reverts commit r208934.
The patch depends on aliases to GEPs with non zero offsets. That is not
supported and fairly broken.
The good news is that GlobalAlias is being redesigned and will have support
for offsets, so this patch should be a nice match for it.
llvm-svn: 208978
This commit implements two command line switches -global-merge-on-external
and -global-merge-aligned, and both of them are false by default, so this
optimization is disabled by default for all targets.
For ARM64, some back-end behaviors need to be tuned to get this optimization
further enabled.
llvm-svn: 208934
Since type units in the dwo file are handled by a debug aware tool, they
don't need to leverage the ELF comdat grouping to implement
deduplication. Avoid creating all the .group sections for these as a
space optimization.
llvm-svn: 208930
Abstract variables should never have/use locations. In this case the
data wasn't used, so no functional change intended here, just
simplification.
llvm-svn: 208820
Many old tests using prior schemas still had some brokenness here (both
indirect arrays and arrays with single bogus elements). Fixed those up
so they don't hit the new assertions.
Also reduced nesting in some places, etc.
llvm-svn: 208817
