Commit Graph

3420 Commits

Author SHA1 Message Date
Jessica Paquette a0aa5b35e7 Output per-function size-info remarks
This patch adds per-function size information remarks. Previously, passing
-Rpass-analysis=size-info would only give you per-module changes. By adding
the ability to do this per-function, it's easier to see which functions
contributed the most to size changes.

https://reviews.llvm.org/D51467

llvm-svn: 341588
2018-09-06 21:19:54 +00:00
David Green e6918ca2b3 [SLC] Add an alignment to CreateGlobalString
Previously the alignment on the newly created global strings was not set,
meaning that DataLayout::getPreferredAlignment was free to overalign it
to 16 bytes. This caused unnecessary code bloat with the padding between
variables.

The main example of this happening was the printf->puts optimisation in
SimplifyLibCalls, but as the change here is made in
IRBuilderBase::CreateGlobalString, other globals using this will now be
aligned too.

Differential Revision: https://reviews.llvm.org/D51410

llvm-svn: 341527
2018-09-06 08:42:17 +00:00
Jessica Paquette 31d2e5e546 [NFC] Improve clarity in emitInstrCountChangedRemark
Add a "CouldOnlyImpactOneFunction" bool that's true when we pass in a function.

Just cleaning up a little bit, since I'm going to add in the per-function
remarks soon from D51467.

llvm-svn: 341407
2018-09-04 21:03:43 +00:00
Chandler Carruth 664aa868f5 [x86/SLH] Add a real Clang flag and LLVM IR attribute for Speculative
Load Hardening.

Wires up the existing pass to work with a proper IR attribute rather
than just a hidden/internal flag. The internal flag continues to work
for now, but I'll likely remove it soon.

Most of the churn here is adding the IR attribute. I talked about this
Kristof Beyls and he seemed at least initially OK with this direction.
The idea of using a full attribute here is that we *do* expect at least
some forms of this for other architectures. There isn't anything
*inherently* x86-specific about this technique, just that we only have
an implementation for x86 at the moment.

While we could potentially expose this as a Clang-level attribute as
well, that seems like a good question to defer for the moment as it
isn't 100% clear whether that or some other programmer interface (or
both?) would be best. We'll defer the programmer interface side of this
for now, but at least get to the point where the feature can be enabled
without relying on implementation details.

This also allows us to do something that was really hard before: we can
enable *just* the indirect call retpolines when using SLH. For x86, we
don't have any other way to mitigate indirect calls. Other architectures
may take a different approach of course, and none of this is surfaced to
user-level flags.

Differential Revision: https://reviews.llvm.org/D51157

llvm-svn: 341363
2018-09-04 12:38:00 +00:00
Fedor Sergeev f2d4372e0e [PassTiming] reporting time-passes separately for multiple pass instances of the same pass
Summary:
Refactoring done by rL340872 accidentally appeared to be non-NFC, changing the way how
multiple instances of the same pass are handled - aggregation of results by PassName
forced data for multiple instances to be merged together and reported as one line.

Getting back to creating/reporting timers per pass instance.
Reporting was a bit enhanced by counting pass instances and adding #<num> suffix
to the pass description. Note that it is instances that are being counted,
not invocations of them.

time-passes test updated to account for multiple passes being run.

Reviewers: paquette, jhenderson, MatzeB, skatkov

Reviewed By: skatkov

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D51535

llvm-svn: 341346
2018-09-04 06:12:28 +00:00
Jessica Paquette a69696dca6 Fix typo in size remarks for module passes
ModuleCount = InstrCount was incorrect. It should have been
InstrCount = ModuleCount. This was making it emit an extra, incorrect remark
for Print Module IR.

The test didn't catch this, because it didn't ensure that the only remark
output was from the desired pass. So, it was possible to have an extra remark
come through and not fail. Updated the test so that we ensure that the last
remark that's output comes from the desired pass. This is done by ensuring
that whatever is being read after the last remark is YAML output rather than
some incorrect garbage.

llvm-svn: 341267
2018-08-31 22:43:41 +00:00
Jessica Paquette 71e9778006 [NFC] Optionally pass a function to emitInstrCountChangedRemark
In basic block, loop, and function passes, we already have a function that
we can use to emit optimization remarks. We can use that instead of searching
the module for the first suitable function (that is, one that contains at
least one basic block.)

llvm-svn: 341253
2018-08-31 20:54:37 +00:00
Jessica Paquette 397c05dd7d [NFC] Check if P is a pass manager on entry to emitInstrCountChangedRemark
There's no point in finding a function to use for remark output when we're
not going to emit anything.

llvm-svn: 341252
2018-08-31 20:51:54 +00:00
Jessica Paquette 9a23c55920 [NFC] Pass the instruction delta to emitInstrCountChangedRemark
Instead of counting the size of the entire module every time we run a pass,
pass along a delta instead and use that to emit the remark.

This means we only have to use (on average) smaller IR units to calculate
instruction counts. E.g, in a BB pass, we only need to look at the delta of
the BB instead of the delta of the entire module.

6/6

(This improved compile time for size remarks on sqlite3 + O2 significantly)

llvm-svn: 341250
2018-08-31 20:20:57 +00:00
Jessica Paquette 454d1032e9 [NFC] Pre-calculate module IR counts in size remarks.
Same as the previous NFC commits in the same vein.

This one introduces a TODO. I'm going to change emitInstrCountChangedRemark
so that it takes in a delta. Since the delta isn't necessary yet, it's not
there. For now, this means that we're calculating the size of the module
twice.

Just done separately to keep the patches small.

4/6

llvm-svn: 341248
2018-08-31 20:20:55 +00:00
Jessica Paquette 9eda13e976 [NFC] Pre-calculate basic block IR counts in size remarks.
Size remarks are slow due to lots of recalculation of the module.

This is similar to the previous commit. Cache the size of the module and
update counts in basic block passes based off a less-expensive delta.

2/6

llvm-svn: 341246
2018-08-31 20:20:53 +00:00
Jessica Paquette f2a202ce7a [NFC] Pre-calculate function IR counts in size remarks.
Size remarks are slow due to lots of recalculation of the module.

Pre-calculate the module size and initial function size for a remark. Use
deltas calculated using the less-expensive function IR count to update the
module counts for Function passes.

1/6

llvm-svn: 341245
2018-08-31 20:19:41 +00:00
Robert Widmann 0a35b7668b [LLVM-C] Add Bindings For Named Metadata
Summary: Add a new type for named metadata nodes.  Use this to implement iterators and accessors for NamedMDNodes and extend the echo test to use them to copy module-level debug information.

Reviewers: whitequark, deadalnix, aprantl, dexonsmith

Reviewed By: whitequark

Subscribers: Wallbraker, JDevlieghere, llvm-commits, harlanhaskins

Differential Revision: https://reviews.llvm.org/D47179

llvm-svn: 341085
2018-08-30 17:09:43 +00:00
Sanjay Patel 8d39ed895f [IR] fix declaration of shuffle mask
An address sanitizer bot flagged this as a potential bug.

llvm-svn: 341084
2018-08-30 16:44:07 +00:00
Sanjay Patel ac619a09ec [IR] add shuffle queries for identity extend/extract
This was one of the potential follow-ups suggested in D48236, 
and these will be used to make matching the patterns in PR38691 cleaner:
https://bugs.llvm.org/show_bug.cgi?id=38691

About the vocabulary: in the DAG, these would be concat_vector with an 
undef operand or extract_subvector. Alternate names are discussed in the
review, but I think these are familiar/good enough to proceed. Once we
have uses of them in code, we might adjust if there are better options.

https://reviews.llvm.org/D51392

llvm-svn: 341075
2018-08-30 15:05:38 +00:00
Eli Friedman 3769639335 [NFC] Make getPreferredAlignment honor section markings.
This should more accurately reflect what the AsmPrinter will actually
do.

This is NFC, as far as I can tell; all the places that might be affected
already have an extra check to avoid using the result of
getPreferredAlignment in this situation.

Differential Revision: https://reviews.llvm.org/D51377

llvm-svn: 340999
2018-08-29 23:46:26 +00:00
Fedor Sergeev 43083111a2 [NFC][PassTiming] factor out generic PassTimingInfo
Moving PassTimingInfo from legacy pass manager code into a separate header.
Making it suitable for both legacy and new pass manager.
Adding a test on -time-passes main functionality.

llvm-svn: 340872
2018-08-28 21:06:51 +00:00
Chandler Carruth 9ae926b973 [IR] Replace `isa<TerminatorInst>` with `isTerminator()`.
This is a bit awkward in a handful of places where we didn't even have
an instruction and now we have to see if we can build one. But on the
whole, this seems like a win and at worst a reasonable cost for removing
`TerminatorInst`.

All of this is part of the removal of `TerminatorInst` from the
`Instruction` type hierarchy.

llvm-svn: 340701
2018-08-26 09:51:22 +00:00
Chandler Carruth 698fbe7b59 [IR] Sink `isExceptional` predicate to `Instruction`, rename it to
`isExceptionalTermiantor` and implement it for opcodes as well following
the common pattern in `Instruction`.

Part of removing `TerminatorInst` from the `Instruction` type hierarchy
to make it easier to share logic and interfaces between instructions
that are both terminators and not terminators.

llvm-svn: 340699
2018-08-26 08:56:42 +00:00
Chandler Carruth 96fc1de77d [IR] Begin removal of TerminatorInst by removing successor manipulation.
The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which are terminators.

The iterator and *generic* range based access move to `CFG.h` where all
the other generic successor and predecessor access lives. While moving
the iterator here, simplify it using the iterator utilities LLVM
provides and updates coding style as much as reasonable. The APIs remain
pointer-heavy when they could better use references, and retain the odd
behavior of `operator*` and `operator->` that is common in LLVM
iterators. Adjusting this API, if desired, should be a follow-up step.

Non-generic range iteration is added for the two instructions where
there is an especially easy mechanism and where there was code
attempting to use the range accessor from a specific subclass:
`indirectbr` and `br`. In both cases, the successors are contiguous
operands and can be easily iterated via the operand list.

This is the first major patch in removing the `TerminatorInst` type from
the IR's instruction type hierarchy. This change was discussed in an RFC
here and was pretty clearly positive:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html

There will be a series of much more mechanical changes following this
one to complete this move.

Differential Revision: https://reviews.llvm.org/D47467

llvm-svn: 340698
2018-08-26 08:41:15 +00:00
Robert Widmann 106eab0292 [C-API][DIBuilder] Use NameLen in LLVMDIBuilderCreateParameterVariable
Summary: NameLen wasn't being used and caused the parameters in gdb to very long, in my case, crashes in others. Please also perform the correct magical incarnations to have this be applied to the LLVM 7 branch.

Reviewers: whitequark, CodaFi

Reviewed By: CodaFi

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D51141

llvm-svn: 340691
2018-08-25 19:54:39 +00:00
Adrian Prantl 4ddd059635 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
Adrian Prantl 3807217d02 Verifier: verify that a DILocation's scope is a DILocalScope.
This fixes an assertion failure(!) in the Verifier.

rdar://problem/43687474

llvm-svn: 340653
2018-08-24 21:01:58 +00:00
David Blaikie 2a813ef208 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 075412d9cf [DEBUGINFO] Fix misprint in the name of DebugDirectivesOnly, NFC.
llvm-svn: 340553
2018-08-23 17:43:40 +00:00
Alexander Richardson 6bcf2ba2f0 Allow creating llvm::Function in non-zero address spaces
Most users won't have to worry about this as all of the
'getOrInsertFunction' functions on Module will default to the program
address space.

An overload has been added to Function::Create to abstract away the
details for most callers.

This is based on https://reviews.llvm.org/D37054 but without the changes to
make passing a Module to Function::Create() mandatory. I have also added
some more tests and fixed the LLParser to accept call instructions for
types in the program address space.

Reviewed By: bjope

Differential Revision: https://reviews.llvm.org/D47541

llvm-svn: 340519
2018-08-23 09:25:17 +00:00
Serguei Katkov 09ab506798 [IR Verifier] Do not allow bitcast of pointer to vector of pointers and vice versa.
LangRef for BitCast requires that
"The bit sizes of value and the destination type, ty2, must be identical".
Currently verifier allows BitCast of pointer to vector of pointers so that
the sizes are different.

This change fixes that.

Reviewers: arsenm
Reviewed By: arsenm
Subscribers: llvm-commits, wdng
Differential Revision: https://reviews.llvm.org/D50886

llvm-svn: 340249
2018-08-21 04:27:07 +00:00
Craig Topper 4ee28412a5 [LegacyPassManager] Remove analysis P from AnUsageMap before deleting it in schedulePass.
If we deem the analysis pass useless and delete it, we need to make sure we remove it from AnUsageMap. Otherwise we might allocate another pass in the freed memory. This will cause us to reuse the AnalysisUsage from the original pass instead of the new one.

Fixes PR38511

Differential Revision: https://reviews.llvm.org/D50573

llvm-svn: 340210
2018-08-20 20:57:30 +00:00
Sanjay Patel 3ce999fa41 [ConstantFolding] improve folding of binops with vector undef operand
A non-undef operand may still have undef constant elements, 
so we should always propagate the vector results per-lane.

llvm-svn: 340194
2018-08-20 18:19:02 +00:00
whitequark b56a4d3149 [C-API][DIBuilder] Added DIFlags in LLVMDIBuilderCreateBasicType
Added DIFlags in LLVMDIBuilderCreateBasicType to add optional DWARF
attributes, such as DW_AT_endianity.

Patch by Chirag Patel.

Differential Revision: https://reviews.llvm.org/D50832

llvm-svn: 340146
2018-08-19 23:39:47 +00:00
Teresa Johnson cb9a82fc7b [ThinLTO] Add option for printing import failure reasons
Summary:
Adds the option for the printing of summary information about functions
considered but rejected for importing during the thin link.

Reviewers: davidxl

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D50881

llvm-svn: 340047
2018-08-17 16:53:47 +00:00
Alina Sbirlea d4b3f19ba6 [DomTree] Add constructor to create a new DT based on current DT/CFG and a set of Updates.
Summary:
Add the posibility of creating a new DT using a set of Updates.
This will essentially create a DT based on a CFG snapshot/view.

Additional refactoring for either this patch or follow-ups:
- create an utility for building BUI.
- replace BUI with a GraphDiff.

Reviewers: kuhar

Subscribers: sanjoy, jlebar, llvm-commits

Differential Revision: https://reviews.llvm.org/D50671

llvm-svn: 339947
2018-08-16 21:54:33 +00:00
David Blaikie 66cf14d06b 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
Craig Topper 9c1d9fdeaa [X86] Remove masking from the 512-bit padds and psubs intrinsics. Use select in IR instead.
llvm-svn: 339842
2018-08-16 06:20:24 +00:00
Craig Topper 9d6983c9fd [X86] Remove the unused masked 128 and 256-bit masked padds/psubs intrinsics.
Still need to remove masking from the 512-bit versions.

llvm-svn: 339841
2018-08-16 06:20:22 +00:00
George Burgess IV 3083105b81 [Metadata] Replace a SmallVector with an array; NFC
MDNode::get takes an ArrayRef, so these should be equivalent.

llvm-svn: 339824
2018-08-15 22:15:35 +00:00
Adrian Prantl 55f4262999 [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
Alina Sbirlea 148c445475 [DomTree] Cleanup Update and LegalizeUpdate API moved to Support header.
Summary:
Clean-up following D50479.
Make Update and LegalizeUpdate refer to the utilities in Support/CFGUpdate.

Reviewers: kuhar

Subscribers: sanjoy, jlebar, mgrang, llvm-commits

Differential Revision: https://reviews.llvm.org/D50669

llvm-svn: 339694
2018-08-14 17:12:30 +00:00
Simon Pilgrim 7bae71a209 Fix MSVC "compiler limit: blocks nested too deeply" error. NFCI.
MSVC only accepts if-else chains up to 127 blocks long. I've had to merge a number of intrinsic cases together to get back below this limit, resulting in some duplication of string matches; this shouldn't cause any notable increase in runtime (and even then only for old IR, nothing that clang currently emits).

llvm-svn: 339666
2018-08-14 10:04:14 +00:00
Tomasz Krupa 86a63889f3 [X86] Lowering addus/subus intrinsics to native IR
Summary: This revision improves previous version (rL330322) which has been reverted due to crashes.

This is the patch that lowers x86 intrinsics to native IR
in order to enable optimizations. The patch also includes folding
of previously missing saturation patterns so that IR emits the same
machine instructions as the intrinsics.

Reviewers: craig.topper, spatel, RKSimon

Reviewed By: craig.topper

Subscribers: mike.dvoretsky, DavidKreitzer, sroland, llvm-commits

Differential Revision: https://reviews.llvm.org/D46179

llvm-svn: 339650
2018-08-14 08:00:56 +00:00
Teresa Johnson c7816800d8 [ThinLTO] Handle optional args in assembly format for ConstVCalls
Summary:
The AsmWriter was only writing the Args for a ConstVCall if it was
non-empty, however, the LLParser was always expecting it. To aid
in making it optional, surround the ConstVCall VFuncId and Args in
parentheses when writing, then make the Args optional when reading.

Reviewers: pcc

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D49960

llvm-svn: 339637
2018-08-14 01:49:33 +00:00
Chijun Sima ce698a5586 [Dominators] Remove the DeferredDominance class
Summary: After converting all existing passes to use the new DomTreeUpdater interface, there isn't any usage of the original DeferredDominance class. Thus, we can safely remove it from the codebase.

Reviewers: kuhar, brzycki, dmgreen, davide, grosser

Reviewed By: kuhar, brzycki

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D49747

llvm-svn: 339502
2018-08-11 08:12:07 +00:00
JF Bastien e69ae76b20 [NFC] Remove magic bool param in RAUW
Use an enum class instead.

llvm-svn: 339366
2018-08-09 18:28:54 +00:00
Hsiangkai Wang ef72e481ea [DebugInfo] Refactor DbgInfoIntrinsic class hierarchy.
In the past, DbgInfoIntrinsic has a strong assumption that these
intrinsics all have variables and expressions attached to them.
However, it is too strong to derive the class for other debug entities.
Now, it has problems for debug labels.

In order to make DbgInfoIntrinsic as a base class for 'debug info', I
create a class for 'variable debug info', DbgVariableIntrinsic.

DbgDeclareInst, DbgAddrIntrinsic, and DbgValueInst will be derived from it.

Differential Revision: https://reviews.llvm.org/D50220

llvm-svn: 338984
2018-08-06 03:59:47 +00:00
Chijun Sima c72ff1011d [Dominators] Refine the logic of recalculate() in the DomTreeUpdater
Summary:
This patch refines the logic of `recalculate()` in the `DomTreeUpdater` in the following two aspects:
1. Previously, `recalculate()` tests whether there are pending updates/BBs awaiting deletion and then do recalculation under Lazy UpdateStrategy; and do recalculation immediately under Eager UpdateStrategy. (The former behavior is inherited from the `DeferredDominance` class). This is an inconsistency between two strategies and there is no obvious reason to do this. So the behavior is changed to always recalculate available trees when calling `recalculate()`.
2. Fix the issue of when DTU under Lazy UpdateStrategy holds nothing but with BBs awaiting deletion, after calling `recalculate()`, BBs awaiting deletion aren't flushed. An additional unittest is added to cover this case.

Reviewers: kuhar, dmgreen, brzycki, grosser, davide

Reviewed By: kuhar

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50173

llvm-svn: 338822
2018-08-03 06:51:35 +00:00
Nick Desaulniers 9ff1489d50 Add maybe-unused attribute to a variable.
Summary:
Mark a variable as maybe-unused to prevent a -Wunused-but-set-variable
warning in optimized builds where asserts are removed.Test/first commit
to check setup and understand patch submission process.

Reviewers: srhines, pirama, dblaikie

Reviewed By: dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D49756

llvm-svn: 338654
2018-08-01 23:46:48 +00:00
Alexey Bataev d4dd7215f6 [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
Fangrui Song f78650a8de Remove trailing space
sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h}

llvm-svn: 338293
2018-07-30 19:41:25 +00:00
Manoj Gupta 9d83ce9043 [Inline] Copy "null-pointer-is-valid" attribute in caller.
Summary:
Normally, inling does not happen if caller does not have
"null-pointer-is-valid"="true" attibute but callee has it.

However, alwaysinline may force callee to be inlined.
In this case, if the caller has the "null-pointer-is-valid"="true"
attribute, copy the attribute to caller.

Reviewers: efriedma, a.elovikov, lebedev.ri, jyknight

Reviewed By: efriedma

Subscribers: eraman, llvm-commits

Differential Revision: https://reviews.llvm.org/D50000

llvm-svn: 338292
2018-07-30 19:33:53 +00:00
Vedant Kumar b572f64212 [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