This patch makes instruction-referencing accepts an additional scenario
where values can be read from physical registers at the start of blocks. As
far as I was aware, this only happened:
* With arguments in the entry block,
* With constant physical registers,
To which this patch adds a third case:
* With exception-handling landing-pad blocks
In the attached test: the operand of the dbg.value traces back to the
"landingpad" instruction, which becomes some copies from physregs. Right
now, that's deemed unacceptable, and the assertion fires. The fix is to
just accept this scenario; this is a case where the value in question is
defined by a register and a position, not by an instruction that defines
it. Reading it with a DBG_PHI is the correct behaviour, there isn't a
non-copy instruction that we can refer to.
Differential Revision: https://reviews.llvm.org/D109005
This patch emits DW_TAG_namelist and DW_TAG_namelist_item for fortran
namelist variables. DICompositeType is extended to support this fortran
feature.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D108553
New field `elements` is added to '!DIImportedEntity', representing
list of aliased entities.
This is needed to dump optimized debugging information where all names
in a module are imported, but a few names are imported with overriding
aliases.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D109343
This does add some extra superfluous whitespace (eg: "int *") intended
to make the Simplified Template Names work easier - this makes the
DIE-based names match more exactly the clang-generated names, so it's
easier to identify cases that don't generate matching names.
(arguably we could change clang to skip that whitespace or add some
fuzzy matching to accommodate differences in certain whitespace - but
this seemed easier and fairly low-impact)
This patch emits DW_TAG_namelist and DW_TAG_namelist_item for fortran
namelist variables. DICompositeType is extended to support this fortran
feature.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D108553
InstrRefBasedLDV is marginally slower than VarlocBasedLDV when analysing
optimised code -- however, it's much slower when analysing code compiled
-O0.
To avoid this: don't use instruction referencing for -O0 functions. In the
"pure" case of unoptimised code, this won't really harm the debugging
experience because most variables won't have been promoted off the stack,
so can't go missing. It becomes more complicated when optimised code is
inlined into functions marked optnone; however these are rare, and as -O0
doesn't run many optimisations there should be little damage to the debug
experience as a result.
I've taken the opportunity to refactor testing for instruction-referencing
into a MachineFunction method, which seems the most appropriate place to
put it.
Differential Revision: https://reviews.llvm.org/D108585
This ensures that debug_types references aren't looked for in
debug_info section.
Behavior is still going to be questionable in an unlinked object file -
since cross-cu references could refer to symbols in another .debug_info
(or, in theory, .debug_types) chunk - but if a producer only uses
ref_addr to refer to things within the same .debug_info chunk in an
object file (eg: whole program optimization/LTO - producing two CUs into
a single .debug_info section in an object file - the ref_addrs there
could be resolved relative to that .debug_info chunk, not needing to
consider comdat (DWARFv5 type units or other creatures) chunks of
.debug_info, etc)
This patch is a revert of e08f205f5c2c. In that patch, DW_TAG_subprograms
were permitted to be referenced across CU boundaries, to improve stack
trace construction using call site information. Unfortunately, as
documented in PR48790, the way that subprograms are "owned" by dwarf units
is sufficiently complicated that subprograms end up in unexpected units,
invalidating cross-unit references.
There's no obvious way to easily fix this, and several attempts have
failed. Revert this to ensure correct DWARF is always emitted.
Three tests change in addition to the reversion, but they're all very
light alterations.
Differential Revision: https://reviews.llvm.org/D107076
It's entirely possible (because it actually happened) for a bool
variable to end up with a 256-bit DW_AT_const_value. This came about
when a local bool variable was initialized from a bitfield in a
32-byte struct of bitfields, and after inlining and constant
propagation, the variable did have a constant value. The sequence of
optimizations had it carrying "i256" values around, but once the
constant made it into the llvm.dbg.value, no further IR changes could
affect it.
Technically the llvm.dbg.value did have a DIExpression to reduce it
back down to 8 bits, but the compiler is in no way ready to emit an
oversized constant *and* a DWARF expression to manipulate it.
Depending on the circumstances, we had either just the very fat bool
value, or an expression with no starting value.
The sequence of optimizations that led to this state did seem pretty
reasonable, so the solution I came up with was to invent a DWARF
constant expression folder. Currently it only does convert ops, but
there's no reason it couldn't do other ops if that became useful.
This broke three tests that depended on having convert ops survive
into the DWARF, so I added an operator that would abort the folder to
each of those tests.
Differential Revision: https://reviews.llvm.org/D106915
When we build with split dwarf in single mode the .o files that contain both "normal" debug sections and dwo sections, along with relocaiton sections for "normal" debug sections.
When we create DWARF context in DWARFObjInMemory we process relocations and store them in the map for .debug_info, etc section.
For DWO Context we also do it for non dwo dwarf sections. Which I believe is not necessary. This leads to a lot of memory being wasted. We observed 70GB extra memory being used.
I went with context sensitive approach, flag is passed in. I am not sure if it's always safe not to process relocations for regular debug sections if Obj contains .dwo sections.
If it is alternatvie might be just to scan, in constructor, sections and if there are .dwo sections not to process regular debug ones.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D106624
The way this test generates object file results in relocation sections for .dwo sections. This is not legal. Re-wrote it to avoid those relocation sections.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D107012
When working out which instruction defines a value, the
instruction-referencing variable location code has a few special cases for
physical registers:
* Arguments are never defined by instructions,
* Constant physical registers always read the same value, are never def'd
This patch adds a third case for the llvm.frameaddress intrinsics: you can
read the framepointer in any block if you so choose, and use it as a
variable location, as shown in the added test.
This rather violates one of the assumptions behind instruction referencing,
that LLVM-ir shouldn't be able to read from an arbitrary register at some
arbitrary point in the program. The solution for now is to just emit a
DBG_PHI that reads the register value: this works, but if we wanted to do
something clever with DBG_PHIs in the future then this would probably get
in the way. As it stands, this patch avoids a crash.
Differential Revision: https://reviews.llvm.org/D106659
If you attach __attribute__((optnone)) to a function when using
optimisations, that function will use fast-isel instead of the usual
SelectionDAG method. This is a problem for instruction referencing,
because it means DBG_VALUEs of virtual registers will be created,
triggering some safety assertions in LiveDebugVariables. Those assertions
exist to detect exactly this scenario, where an unexpected piece of code is
generating virtual register references in instruction referencing mode.
Fix this by transforming the DBG_VALUEs created by fast-isel into
half-formed DBG_INSTR_REFs, after which they get patched up in
finalizeDebugInstrRefs. The test modified adds a fast-isel mode to the
instruction referencing isel test.
Differential Revision: https://reviews.llvm.org/D105694
For Clang, `MCUseDwarfDirectory` is true by default for the majority cases
(-fintegrated-as or -gdwarf-5; most targets use -fintegrated-as by default).
Defaulting MCUseDwarfDirectory to true can reduce the differences between clang
and llc.
Reviewed By: #debug-info, dblaikie
Differential Revision: https://reviews.llvm.org/D105856
Originally committed as 04c203e310bd3fb58e16c936c0200d680100526e
Reverted in 768510632c5ddbf9438693d9c7db1903e39295ad due to the test
failing when encountering windows directory separators.
Fix the path separator platform issue with a FileCheck pattern {{[/\\]}}
Original commit message:
A followup to the feature added in 69da27c7496ea373567ce5121e6fe8613846e7a5
that added the optional "start file name" to match "start line" - but this
didn't work with Split DWARF because of the need for the decl file number
resolution code to refer back to the skeleton unit to find its .debug_line
contribution. So this patch adds the necessary infrastructure to track the
skeleton unit corresponding to a split full unit for the purpose of this
lookup.
A followup to the feature added in
69da27c7496ea373567ce5121e6fe8613846e7a5 that added the optional "start
file name" to match "start line" - but this didn't work with Split DWARF
because of the need for the decl file number resolution code to refer
back to the skeleton unit to find its .debug_line contribution. So this
patch adds the necessary infrastructure to track the skeleton unit
corresponding to a split full unit for the purpose of this lookup.
This patch emits DBG_INSTR_REFs for two remaining flavours of variable
locations that weren't supported: copies, and inter-block VRegs. There are
still some locations that must be represented by DBG_VALUE such as
constants, but they're mostly independent of optimisations.
For variable locations that refer to values defined in different blocks,
vregs are allocated before isel begins, but the defining instruction
might not exist until late in isel. To get around this, emit
DBG_INSTR_REFs in a "half done" state, where the first operand refers to a
VReg. Then at the end of isel, patch these back up to refer to
instructions, using the finalizeDebugInstrRefs method.
Copies are something that I complained about the original RFC, and I
really don't want to have to put instruction numbers on copies. They don't
define a value: they move them. To address this isel, salvageCopySSA
interprets:
* COPYs,
* SUBREG_TO_REG,
* Anything that isCopyInstr thinks is a copy.
And follows chains of copies back to the defining instruction that they
read from. This relies on any physical registers that COPYs read being
defined in the same block, or being entry-block arguments. For the former
we can put an instruction number on the defining instruction; for the
latter we can drop a DBG_PHI that reads the incoming value.
Differential Revision: https://reviews.llvm.org/D88896
This patch fixes an issue which occurred in CodeGenPrepare and
HWAddressSanitizer, which both at some point create a map of Old->New
instructions and update dbg.value uses of these. They did this by
iterating over the dbg.value's location operands, and if an instance of
the old instruction was found, replaceVariableLocationOp would be
called on that dbg.value. This would cause an error if the same operand
appeared multiple times as a location operand, as the first call to
replaceVariableLocationOp would update all uses of the old instruction,
invalidating the old iterator and eventually hitting an assertion.
This has been fixed by no longer iterating over the dbg.value's location
operands directly, but by first collecting them into a set and then
iterating over that, ensuring that we never attempt to replace a
duplicated operand multiple times.
Differential Revision: https://reviews.llvm.org/D105129
This patch adds support to the instruction-referencing LiveDebugValues
implementation for emitting entry values. The instruction referencing
implementations tracking by value rather than location means that we can
get around two of the issues with VarLocs. DBG_VALUE instructions that
re-assign the same value to a variable are no longer a problem, because we
can "see through" to the value being assigned. We also don't need to do
anything special during the dataflow stages: the "variable value problem"
doesn't need to know whether a value is available most of the time, and the
times it deoes need to know are always when entry values need to be
terminated.
The patch modifies the "TransferTracker" class, adding methods to identify
when a variable ias an entry value candidate, and when a machine value is
an entry value. recoverAsEntryValue tests these two things and emits an
entry-value expression if they're true. It's used when we clobber or
otherwise lose a value and can't find a replacement location for the value
it contained.
Differential Revision: https://reviews.llvm.org/D88406
This will currently accept the old number of bytes syntax, and convert
it to a scalar. This should be removed in the near future (I think I
converted all of the tests already, but likely missed a few).
Not sure what the exact syntax and policy should be. We can continue
printing the number of bytes for non-generic instructions to avoid
test churn and only allow non-scalar types for generic instructions.
This will currently print the LLT in parentheses, but accept parsing
the existing integers and implicitly converting to scalar. The
parentheses are a bit ugly, but the parser logic seems unable to deal
without either parentheses or some keyword to indicate the start of a
type.
A combination of features ^ that lead to a mismatch of expectations
about how a subprogram definition DIE would be produced with/without a
declaration when taking full -g debug info and inlining it into a -gmlt
CU - specifically when using Split DWARF that doesn't support cross-CU
references, so we have to put the -g debug info into the -gmlt CU, which
gets confusing about which mode is respected.
This patch comes down on respecting the CU the debug info is emitted
into, rather than preserving the full debug info when it's emitted into
the gmlt CU.
D85085 was pushed earlier but broke tests on mac and win:
http://lab.llvm.org:8080/green/job/clang-stage1-RA/21182/consoleFull#-706149783d489585b-5106-414a-ac11-3ff90657619c
Recommitting it after adding mtriple to the llc commands.
Emit correct location lists with basic block sections.
This patch addresses multiple things:
1) It ensures that const_value is emitted when possible with basic block
sections.
2) It emits location lists such that the labels are always within the
section boundary.
3) It fixes a bug when the parameter is first used in a non-entry block
which is in a different section from the entry block.
Differential Revision: https://reviews.llvm.org/D85085
The D35953, D62650 and D73691 introduced trimming of variables locations
in LiveDebugVariables pass, since there are some cases where after
the virtregrewrite we have exploded number of DBG_VALUEs created for some
inlined variables. As it looks, all problematic cases were regarding
inlined variables, so it seems reasonable to stop trimming the location
ranges for non-inlined variables.
It has very good impact on the llvm-locstats report.
Differential Revision: https://reviews.llvm.org/D102917
Breaks check-llvm on non-linux, see comments on https://reviews.llvm.org/D85085
This reverts commit caae570978c490a137921b9516162a382831209e
and follow-up commit 1546c52d971292ed4145b6d41aaca0d02229ebff.
This patch addresses multiple things:
1) It ensures that const_value is emitted when possible with basic block
sections.
2) It emits location lists such that the labels are always within the
section boundary.
3) It fixes a bug when the parameter is first used in a non-entry block
which is in a different section from the entry block.
Differential Revision: https://reviews.llvm.org/D85085
Since d6de1e1a71406c75a4ea4d5a2fe84289f07ea3a1, no attributes is quivalent to
setting attribute to false.
This is a preliminary commit for https://reviews.llvm.org/D99080
Currently, variadic dbg.values (i.e. those using a DIArgList as part of
their location) are not handled properly by FastISel or GlobalISel, and
will produce invalid DBG_VALUE instructions if they encounter them. This
patch fixes this issue by emitting undef DBG_VALUE instructions for
variadic dbg.values, so that no incorrect instruction is produced and
any prior variable location is terminated.
This is simply a quick-fix to prevent errors; a correct implementation
should come later for these ISel pipelines to ensure that we do not drop
debug information unnecessarily.
Differential Revision: https://reviews.llvm.org/D102500
Reapply b623df3c, which was reverted while reverting a different patch
with a breaking change. There are no underlying issues with this patch,
so no changes have been made to the original patch.
This reverts commit b11e4c990771541e440861f017afea7b4ba162f4.
This patch is a fix for revision ce0c1f3c, which caused test failures on
bots without x86 as a registered target. This patch moves the test added
in the prior patch to the x86 folder, so that it only runs on bots with
the correct target available.
Add tests which can catch the issue in 0ce723cb228bc1d1a0f5718f3862fb836145a333
(If any function needs CFISection::EH, the module should use CFISection::EH).
Reviewed By: echristo
Differential Revision: https://reviews.llvm.org/D101339
This patch fixes a crash in LiveDebugVariables for inputs where a
DBG_VALUE_LIST had 64 or more debug operands. This was triggering an
assert, which was added under the assumption that only bad CodeGen would
result in such a limit being hit, but relatively simple source files
that result in these incredibly long debug values have been found, so
this assert has been changed to a condition that drops the debug value
if it is not met.
Differential Revision: https://reviews.llvm.org/D101373
Negative numbers are represented using DW_OP_consts along with signed representation
of the number as the argument.
Test case IR is generated using Fortran front-end.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D99273
