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Differential Revision: https://reviews.llvm.org/D73534
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This fixes a miscompile that happened because a DBG_VALUE interfered
with the MachineOutliner's liveness analysis.
Inserting a DBG_VALUE after a terminator breaks predicates on MBB such
as isReturnBlock(). And the resulting DBG_VALUE cannot be "live".
I plan to introduce a MachineVerifier check for this situation in a
follow up.
rdar://59859175
Testing: check-llvm, LNT build with a stage2 compiler & entry values
enabled
Differential Revision: https://reviews.llvm.org/D75548
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Make it a compile-time error to pass an int/unsigned/etc to
fromRawInteger.
Hopefully this prevents errors of the form:
```
for (unsigned ID : getVarLocs()) {
auto VL = LocMap[LocIndex::fromRawInteger(ID)];
...
```
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This is part 3 of a 3-part series to address a compile-time explosion
issue in LiveDebugValues.
---
Start encoding register locations within VarLoc IDs, and take advantage
of this encoding to speed up transferRegisterDef.
There is no fundamental algorithmic change: this patch simply swaps out
SparseBitVector in favor of CoalescingBitVector. That changes iteration
order (hence the test updates), but otherwise this patch is NFCI.
The only interesting change is in transferRegisterDef. Instead of doing:
```
KillSet = {}
for (ID : OpenRanges.getVarLocs())
if (DeadRegs.count(ID))
KillSet.add(ID)
```
We now do:
```
KillSet = {}
for (Reg : DeadRegs)
for (ID : intervalsReservedForReg(Reg, OpenRanges.getVarLocs()))
KillSet.add(ID)
```
By not visiting each open location every time we visit an instruction,
this eliminates some potentially quadratic behavior. The new
implementation basically does a constant amount of work per instruction
because the interval map lookups are very fast.
For a file in WebKit, this brings the time spent in LiveDebugValues down
from ~2.5 minutes to 4 seconds, reducing compile time spent in that pass
from 28% of the total to just over 1%.
Before:
```
2.49 min 27.8% 0 s LiveDebugValues::process
2.41 min 27.0% 5.40 s LiveDebugValues::transferRegisterDef
1.51 min 16.9% 1.51 min LiveDebugValues::VarLoc::isDescribedByReg() const
32.73 s 6.1% 8.70 s llvm::SparseBitVector<128u>::SparseBitVectorIterator::operator++()
```
After:
```
4.53 s 1.1% 0 s LiveDebugValues::process
3.00 s 0.7% 107.00 ms LiveDebugValues::transferRegisterCopy
892.00 ms 0.2% 406.00 ms LiveDebugValues::transferSpillOrRestoreInst
404.00 ms 0.1% 32.00 ms LiveDebugValues::transferRegisterDef
110.00 ms 0.0% 2.00 ms LiveDebugValues::getUsedRegs
57.00 ms 0.0% 1.00 ms std::__1::vector<>::push_back
40.00 ms 0.0% 1.00 ms llvm::CoalescingBitVector<>::find(unsigned long long)
```
FWIW, I tried the same approach using SparseBitVector, but got bad
results. To do that, I had to extend SparseBitVector to support 64-bit
indices and expose its lower bound operation. The problem with this is
that the performance is very hard to predict: SparseBitVector's lower
bound operation falls back to O(n) linear scans in a std::list if you're
not /very/ careful about managing iteration order. When I profiled this
the performance looked worse than the baseline.
You can see the full CoalescingBitVector-based implementation here:
https://github.com/vedantk/llvm-project/commits/try-coalescing
You can see the full SparseBitVector-based implementation here:
https://github.com/vedantk/llvm-project/commits/try-sparsebitvec-find
Depends on D74984 and D74985.
Differential Revision: https://reviews.llvm.org/D74986
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This is part 2 of a 3-part series to address a compile-time explosion
issue in LiveDebugValues.
---
Each VarLoc has a unique ID: this ID is used to look up a VarLoc in the
VarLocMap, and to virtually insert a VarLoc into a VarLocSet. Instead of
inserting the VarLoc /itself/ into the VarLocSet, we insert just the ID,
because this can be represented efficiently with a SparseBitVector.
This change introduces LocIndex, a layer of abstraction on top of VarLoc
IDs. Prior to this change, an ID was just an index into a vector. With
this change, an ID encodes both an index /and/ a register location. The
type-checker ensures that conversions to and from LocIndex are correct.
For the moment the register location is always 0 (undef). We have plenty
of bits left over to encode physregs, stack slots, and other locations
in the future.
Differential Revision: https://reviews.llvm.org/D74985
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This reverts commit rGfaff707db82d.
A failure found on an ARM 2-stage buildbot.
The investigation is needed.
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Differential Revision: https://reviews.llvm.org/D73534
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This reverts commit rGa82d3e8a6e67.
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This patch enables the debug entry values feature.
- Remove the (CC1) experimental -femit-debug-entry-values option
- Enable it for x86, arm and aarch64 targets
- Resolve the test failures
- Leave the llc experimental option for targets that do not
support the CallSiteInfo yet
Differential Revision: https://reviews.llvm.org/D73534
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For a file in WebKit, this brings the time spent in LiveDebugValues down
from 16 minutes to 2 minutes. The reduction comes from iterating the set
of open variable locations just once in transferRegisterDef. Post-patch,
the most expensive item inside of transferRegisterDef is a call to
VarLoc::isDescribedByReg, which we have to do.
Testing: I built LNT using the Os-g cmake cache with & without this
patch, then diffed the object files to verify there was no binary diff.
rdar://59446577
Differential Revision: https://reviews.llvm.org/D74633
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This reverts commit rG9f6ff07f8a39.
Found a test failure on clang-with-thin-lto-ubuntu buildbot.
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This patch enables the debug entry values feature.
- Remove the (CC1) experimental -femit-debug-entry-values option
- Enable it for x86, arm and aarch64 targets
- Resolve the test failures
- Leave the llc experimental option for targets that do not
support the CallSiteInfo yet
Differential Revision: https://reviews.llvm.org/D73534
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Previously LiveDebugValues pass would consider meta instructions that 'fiddle' with liveness of registers as register definitions when transfering register defs. This would mean that, for example, a KILL instruction would cause LiveDebugValues to terminate the range of an earlier DBG_VALUE instruction resulting in the none propogation of said DBG_VALUE instructions into later blocks.
This patch adds the check and a helpful comment, fixes a test that previously tested for the broken behaviour by coincidence and adds a test specifically for this.
reviewers: vsk, dstenb, djtodoro
Differential Revision: https://reviews.llvm.org/D73210
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Summary:
This is a quickfix for PR44275. An assertion that checks that the
DIExpression is valid failed due to attempting to create an entry value
for an indirect parameter. This started appearing after D69028, as the
indirect parameter started being represented using an DW_OP_deref,
rather than with the DBG_VALUE's second operand, meaning that the
isIndirectDebugValue() check in LiveDebugValues did not exclude such
parameters. A DIExpression that has an entry value operation can
currently not have any other operation, leading to the failed isValid()
check.
This patch simply makes us stop considering emitting entry values
for such parameters. To support such cases I think we at least need
to do the following changes:
* In DIExpression::isValid(): Remove the limitation that a
DW_OP_LLVM_entry_value operation can be the only operation in a
DIExpression.
* In LiveDebugValues::emitEntryValues(): Create an entry value of size
1, so that it only wraps the register operand, and not the whole
pre-existing expression (the DW_OP_deref).
* In LiveDebugValues::removeEntryValue(): Check that the new debug
value has the same debug expression as the original, rather than
checking that the debug expression is empty.
* In DwarfExpression::addMachineRegExpression(): Modify the logic so
that a DW_OP_reg* expression is emitted for the entry value.
That is how GCC emits entry values for indirect parameters. That will
currently not happen to due the DW_OP_deref causing the
!HasComplexExpression to fail. The LocationKind needs to be changed
also, rather than always emitting a DW_OP_stack_value for entry values.
There are probably more things I have missed, but that could hopefully
be a good starting point for emitting such entry values.
Reviewers: djtodoro, aprantl, jmorse, vsk
Reviewed By: aprantl, vsk
Subscribers: hiraditya, llvm-commits
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D71416
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Relanding this after resolving the cause of the test failure.
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The DebugVariable class is a class declared in LiveDebugValues.cpp which
is used to uniquely identify a single variable, using its source
variable, inline location, and fragment info to do so. This patch moves
this class into DebugInfoMetadata.h, making it available in a much
broader scope.
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This reverts commit rG4cfceb910692 due to LLDB test failing.
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The idea is to remove front-end analysis for the parameter's value
modification and leave it to the value tracking system. Front-end in some
cases marks a parameter as modified even the line of code that modifies the
parameter gets optimized, that implies that this will cover more entry
values even. In addition, extending the support for modified parameters
will be easier with this approach.
Since the goal is to recognize if a parameter’s value has changed, the idea
at very high level is: If we encounter a DBG_VALUE other than the entry
value one describing the same variable (parameter), we can assume that the
variable’s value has changed and we should not track its entry value any
more. That would be ideal scenario, but due to various LLVM optimizations,
a variable’s value could be just moved around from one register to another
(and there will be additional DBG_VALUEs describing the same variable), so
we have to recognize such situation (otherwise, we will lose a lot of entry
values) and salvage the debug entry value.
Differential Revision: https://reviews.llvm.org/D68209
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Due to changes in D68206, we remove the DIFlagArgumentNotModified
and its usage.
Differential Revision: https://reviews.llvm.org/D68207
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This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.
I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
recompiles touches affected_files header
342380 95 3604 llvm/include/llvm/ADT/STLExtras.h
314730 234 1345 llvm/include/llvm/InitializePasses.h
307036 118 2602 llvm/include/llvm/ADT/APInt.h
213049 59 3611 llvm/include/llvm/Support/MathExtras.h
170422 47 3626 llvm/include/llvm/Support/Compiler.h
162225 45 3605 llvm/include/llvm/ADT/Optional.h
158319 63 2513 llvm/include/llvm/ADT/Triple.h
140322 39 3598 llvm/include/llvm/ADT/StringRef.h
137647 59 2333 llvm/include/llvm/Support/Error.h
131619 73 1803 llvm/include/llvm/Support/FileSystem.h
Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.
Reviewers: bkramer, asbirlea, bollu, jdoerfert
Differential Revision: https://reviews.llvm.org/D70211
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Summary:
Entry values are considered for parameters that have register-described
DBG_VALUEs in the entry block (along with other conditions).
If a parameter's value has been propagated from the caller to the
callee, then the parameter's DBG_VALUE in the entry block may be
described using a register defined by some instruction, and entry values
should not be emitted for the parameter, which can currently occur.
One such case was seen in the attached test case, in which the second
parameter, which is described by a redefinition of the first parameter's
register, would incorrectly get an entry value using the first
parameter's register. This commit intends to solve such cases by keeping
track of register defines, and ignoring DBG_VALUEs in the entry block
that are described by such registers.
In a RelWithDebInfo build of clang-8, the average size of the set was
27, and in a RelWithDebInfo+ASan build it was 30.
Reviewers: djtodoro, NikolaPrica, aprantl, vsk
Reviewed By: djtodoro, vsk
Subscribers: hiraditya, llvm-commits
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D69889
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Summary:
The conditions that are used to determine if entry values should be
emitted for a parameter are quite many, and will grow slightly
in a follow-up commit, so move those to a helper function, as was
suggested in the code review for D69889.
Reviewers: djtodoro, NikolaPrica
Reviewed By: djtodoro
Subscribers: probinson, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69955
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Refactor usage of isCopyInstrImpl, isCopyInstr and isAddImmediate methods
to return optional machine operand pair of destination and source
registers.
Patch by Nikola Prica
Differential Revision: https://reviews.llvm.org/D69622
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destination and source pair as a return value; NFC
This is breaking MSVC builds: http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/20375
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Refactor usage of isCopyInstrImpl, isCopyInstr and isAddImmediate methods
to return optional machine operand pair of destination and source
registers.
Patch by Nikola Prica
Differential Revision: https://reviews.llvm.org/D69622
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llvm/test/DebugInfo/MIR/X86/live-debug-values-reg-copy.mir failed with
EXPENSIVE_CHECKS enabled, causing the patch to be reverted in
rG2c496bb5309c972d59b11f05aee4782ddc087e71.
This patch relands the patch with a proper fix to the
live-debug-values-reg-copy.mir tests, by ensuring the MIR encodes the
callee-saves correctly so that the CalleeSaved info is taken from MIR
directly, rather than letting it be recalculated by the PEI pass. I've
done this by running `llc -stop-before=prologepilog` on the LLVM
IR as captured in the test files, adding the extra MOV instructions
that were manually added in the original test file, then running `llc
-run-pass=prologepilog` and finally re-added the comments for the MOV
instructions.
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[AArch64][DebugInfo] Do not recompute CalleeSavedStackSize (Take 2)"
This fails on EXPENSIVE_CHECKS builds
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Fixed up test/DebugInfo/MIR/Mips/live-debug-values-reg-copy.mir that
broke r375425.
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llvm-svn: 375444
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Commit message from D66935:
This patch fixes a bug exposed by D65653 where a subsequent invocation
of `determineCalleeSaves` ends up with a different size for the callee
save area, leading to different frame-offsets in debug information.
In the invocation by PEI, `determineCalleeSaves` tries to determine
whether it needs to spill an extra callee-saved register to get an
emergency spill slot. To do this, it calls 'estimateStackSize' and
manually adds the size of the callee-saves to this. PEI then allocates
the spill objects for the callee saves and the remaining frame layout
is calculated accordingly.
A second invocation in LiveDebugValues causes estimateStackSize to return
the size of the stack frame including the callee-saves. Given that the
size of the callee-saves is added to this, these callee-saves are counted
twice, which leads `determineCalleeSaves` to believe the stack has
become big enough to require spilling an extra callee-save as emergency
spillslot. It then updates CalleeSavedStackSize with a larger value.
Since CalleeSavedStackSize is used in the calculation of the frame
offset in getFrameIndexReference, this leads to incorrect offsets for
variables/locals when this information is recalculated after PEI.
This patch fixes the lldb unit tests in `functionalities/thread/concurrent_events/*`
Changes after D66935:
Ensures AArch64FunctionInfo::getCalleeSavedStackSize does not return
the uninitialized CalleeSavedStackSize when running `llc` on a specific
pass where the MIR code has already been expected to have gone through PEI.
Instead, getCalleeSavedStackSize (when passed the MachineFrameInfo) will try
to recalculate the CalleeSavedStackSize from the CalleeSavedInfo. In debug
mode, the compiler will assert the recalculated size equals the cached
size as calculated through a call to determineCalleeSaves.
This fixes two tests:
test/DebugInfo/AArch64/asan-stack-vars.mir
test/DebugInfo/AArch64/compiler-gen-bbs-livedebugvalues.mir
that otherwise fail when compiled using msan.
Reviewed By: omjavaid, efriedma
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68783
llvm-svn: 375425
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llvm-svn: 373741
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Rather than having a mixture of location-state shared between DBG_VALUEs
and VarLoc objects in LiveDebugValues, this patch makes VarLoc the
master record of variable locations. The refactoring means that the
transfer of locations from one place to another is always a performed by
an operation on an existing VarLoc, that produces another transferred
VarLoc. DBG_VALUEs are only created at the end of LiveDebugValues, once
all locations are known. As a plus, there is now only one method where
DBG_VALUEs can be created.
The test case added covers a circumstance that is now impossible to
express in LiveDebugValues: if an already-indirect DBG_VALUE is spilt,
previously it would have been restored-from-spill as a direct DBG_VALUE.
We now don't lose this information along the way, as VarLocs always
refer back to the "original" non-transfer DBG_VALUE, and we can always
work out whether a location was "originally" indirect.
Differential Revision: https://reviews.llvm.org/D67398
llvm-svn: 373727
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When transfering variable locations from one place to another,
LiveDebugValues immediately creates a DBG_VALUE representing that
transfer. This causes trouble if the variable location should
subsequently be invalidated by a loop back-edge, such as in the added
test case: the transfer DBG_VALUE from a now-invalid location is used
as proof that the variable location is correct. This is effectively a
self-fulfilling prophesy.
To avoid this, defer the insertion of transfer DBG_VALUEs until after
analysis has completed. Some of those transfers are still sketchy, but
we don't propagate them into other blocks now.
Differential Revision: https://reviews.llvm.org/D67393
llvm-svn: 373720
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Summary:
This reverts commit r372204.
This change causes build bot failures under msan:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/35236/steps/check-llvm%20msan/logs/stdio:
```
FAIL: LLVM :: DebugInfo/AArch64/asan-stack-vars.mir (19531 of 33579)
******************** TEST 'LLVM :: DebugInfo/AArch64/asan-stack-vars.mir' FAILED ********************
Script:
--
: 'RUN: at line 1'; /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llc -O0 -start-before=livedebugvalues -filetype=obj -o - /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir | /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llvm-dwarfdump -v - | /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir
--
Exit Code: 2
Command Output (stderr):
--
==62894==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0xdfcafb in llvm::AArch64FrameLowering::resolveFrameOffsetReference(llvm::MachineFunction const&, int, bool, unsigned int&, bool, bool) const /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1658:3
#1 0xdfae8a in resolveFrameIndexReference /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1580:10
#2 0xdfae8a in llvm::AArch64FrameLowering::getFrameIndexReference(llvm::MachineFunction const&, int, unsigned int&) const /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1536
#3 0x46642c1 in (anonymous namespace)::LiveDebugValues::extractSpillBaseRegAndOffset(llvm::MachineInstr const&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:582:21
#4 0x4647cb3 in transferSpillOrRestoreInst /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:883:11
#5 0x4647cb3 in process /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:1079
#6 0x4647cb3 in (anonymous namespace)::LiveDebugValues::ExtendRanges(llvm::MachineFunction&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:1361
#7 0x463ac0e in (anonymous namespace)::LiveDebugValues::runOnMachineFunction(llvm::MachineFunction&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:1415:18
#8 0x4854ef0 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/MachineFunctionPass.cpp:73:13
#9 0x53b0b01 in llvm::FPPassManager::runOnFunction(llvm::Function&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1648:27
#10 0x53b15f6 in llvm::FPPassManager::runOnModule(llvm::Module&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1685:16
#11 0x53b298d in runOnModule /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1750:27
#12 0x53b298d in llvm::legacy::PassManagerImpl::run(llvm::Module&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1863
#13 0x905f21 in compileModule(char**, llvm::LLVMContext&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/llc/llc.cpp:601:8
#14 0x8fdc4e in main /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/llc/llc.cpp:355:22
#15 0x7f67673632e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
#16 0x882369 in _start (/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llc+0x882369)
MemorySanitizer: use-of-uninitialized-value /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1658:3 in llvm::AArch64FrameLowering::resolveFrameOffsetReference(llvm::MachineFunction const&, int, bool, unsigned int&, bool, bool) const
Exiting
error: -: The file was not recognized as a valid object file
FileCheck error: '-' is empty.
FileCheck command line: /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir
```
Reviewers: bkramer
Reviewed By: bkramer
Subscribers: sdardis, aprantl, kristof.beyls, jrtc27, atanasyan, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67710
llvm-svn: 372228
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This patch fixes a bug exposed by D65653 where a subsequent invocation
of `determineCalleeSaves` ends up with a different size for the callee
save area, leading to different frame-offsets in debug information.
In the invocation by PEI, `determineCalleeSaves` tries to determine
whether it needs to spill an extra callee-saved register to get an
emergency spill slot. To do this, it calls 'estimateStackSize' and
manually adds the size of the callee-saves to this. PEI then allocates
the spill objects for the callee saves and the remaining frame layout
is calculated accordingly.
A second invocation in LiveDebugValues causes estimateStackSize to return
the size of the stack frame including the callee-saves. Given that the
size of the callee-saves is added to this, these callee-saves are counted
twice, which leads `determineCalleeSaves` to believe the stack has
become big enough to require spilling an extra callee-save as emergency
spillslot. It then updates CalleeSavedStackSize with a larger value.
Since CalleeSavedStackSize is used in the calculation of the frame
offset in getFrameIndexReference, this leads to incorrect offsets for
variables/locals when this information is recalculated after PEI.
Reviewers: omjavaid, eli.friedman, thegameg, efriedma
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D66935
llvm-svn: 372204
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If a stack spill location is overwritten by another spill instruction,
any variable locations pointing at that slot should be terminated. We
cannot rely on spills always being restored to registers or variable
locations being moved by a DBG_VALUE: the register allocator is entitled
to spill a value and then forget about it when it goes out of liveness.
To address this, scan for memory writes to spill locations, even those we
don't consider to be normal "spills". isSpillInstruction and
isLocationSpill distinguish the two now. After identifying spill
overwrites, terminate the open range, and insert a $noreg DBG_VALUE for
that variable.
Differential Revision: https://reviews.llvm.org/D66941
llvm-svn: 371193
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When comparing variable locations, LiveDebugValues currently considers only
the machine location, ignoring any DIExpression applied to it. This is a
problem because that DIExpression can do pretty much anything to the machine
location, for example dereferencing it.
This patch adds DIExpressions to that comparison; now variables based on the
same register/memory-location but with different expressions will compare
differently, and be dropped if we attempt to merge them between blocks. This
reduces variable coverage-range a little, but only because we were producing
broken locations.
Differential Revision: https://reviews.llvm.org/D66942
llvm-svn: 370877
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On release builds, 'MI' isn't used by anything (it's already inserted into a
block by BuildMI), while on non-release builds it's used by a LLVM_DEBUG
statement. Mark as explicitly used to avoid the warning.
llvm-svn: 370870
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Summary:
Change LiveDebugValues so that it inserts entry values after the bundle
which contains the clobbering instruction. Previously it would insert
the debug value after the bundle head using insertAfter(), breaking the
bundle.
Reviewers: djtodoro, NikolaPrica, aprantl, vsk
Reviewed By: vsk
Subscribers: hiraditya, llvm-commits
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D66888
llvm-svn: 370448
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The missing line added by this patch ensures that only spilt variable
locations are candidates for being restored from the stack. Otherwise,
register or constant-value information can be interpreted as a spill
location, through a union.
The added regression test replicates a scenario where this occurs: the
stack load from [rsp] causes the register-location DBG_VALUE to be
"restored" to rsi, when it should be left alone. See PR43058 for details.
Un x-fail a test that was suffering from this from a previous patch.
Differential Revision: https://reviews.llvm.org/D66895
llvm-svn: 370334
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The "join" method in LiveDebugValues does not attempt to join unseen
predecessor blocks if their out-locations aren't yet initialized, instead
the block should be re-visited later to see if any locations have changed
validity. However, because the set of blocks were all being "process"'d
once before "join" saw them, that logic in "join" was actually ignoring
legitimate out-locations on the first pass through. This meant that some
invalidated locations were not removed from the head of loops, allowing
illegal locations to persist.
Fix this by removing the run of "process" before the main join/process loop
in ExtendRanges. Now the unseen predecessors that "join" skips truly are
uninitialized, and we come back to the block at a later time to re-run
"join", see the @baz function added.
This also fixes another fault where stack/register transfers in the entry
block (or any other before-any-loop-block) had their tranfers initially
ignored, and were then never revisited. The MIR test added tests for this
behaviour.
XFail a test that exposes another bug; a fix for this is coming in D66895.
Differential Revision: https://reviews.llvm.org/D66663
llvm-svn: 370328
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LiveDebugValues gives variable locations to blocks, but it should also take
away. There are various circumstances where a variable location is known
until a loop backedge with a different location is detected. In those
circumstances, where there's no agreement on the variable location, it
should be undef / removed, otherwise we end up picking a location that's
valid on some loop iterations but not others.
However, LiveDebugValues doesn't currently do this, see the new testcase
attached. Without this patch, the location of !3 is assumed to be %bar
through the loop. Once it's added to the In-Locations list, it's never
removed, even though the later dbg.value(0... of !3 makes the location
un-knowable.
This patch checks during block-location-joining to see whether any
previously-present locations have been removed in a predecessor. If they
have, the live-ins have changed, and the block needs reprocessing.
Similarly, in transferTerminator, assign rather than |= the Out-Locations
after processing a block, as we may have deleted some previously valid
locations. This will mean that LiveDebugValues performs more propagation
-- but that's necessary for it being correct.
Differential Revision: https://reviews.llvm.org/D66599
llvm-svn: 369778
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LiveDebugValues propagates variable locations between blocks by creating
new DBG_VALUE insts in the successors, then interpreting them when it
passes back through the block at a later time. However, this flushes out
any extra information about the location that LiveDebugValues holds: for
example, connections between variable locations such as discussed in
D65368. And as reported in PR42772 this causes us to lose track of the
fact that a spill-location is actually a spill, not a register location.
This patch fixes that by deferring the creation of propagated DBG_VALUEs
until after propagation has completed: instead location propagation occurs
only by sharing location ID numbers between blocks.
Differential Revision: https://reviews.llvm.org/D66412
llvm-svn: 369508
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In r369026 we disabled spill-recognition in LiveDebugValues for anything
that has a complex expression. This is because it's hard to recover the
complex expression once the spill location is baked into it.
This patch re-enables spill-recognition and slightly adjusts the DBG_VALUE
insts that LiveDebugValues tracks: instead of tracking the last DBG_VALUE
for a variable, it tracks the last _unspilt_ DBG_VALUE. The spill-restore
code is then able to access and copy the original complex expression; but
the rest of LiveDebugValues has to be aware of the slight semantic shift,
and produce a new spilt location if a spilt location is propagated between
blocks.
The test added produces an incorrect variable location (see FIXME), which
will be the subject of future work.
Differential Revision: https://reviews.llvm.org/D65368
llvm-svn: 369092
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Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).
Partial reverts in:
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned&
MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register
PPCFastISel.cpp - No Register::operator-=()
PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned&
MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor
Manual fixups in:
ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned&
HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register
HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register.
PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned&
Depends on D65919
Reviewers: arsenm, bogner, craig.topper, RKSimon
Reviewed By: arsenm
Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65962
llvm-svn: 369041
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This patch avoids a crash caused by DW_OP_LLVM_fragments being dropped
from DIExpressions by LiveDebugValues spill-restore code. The appearance
of a previously unseen fragment configuration confuses LDV, as documented
in PR42773, and reproduced by the test function this patch adds (Crashes
on a x86_64 debug build).
To avoid this, on spill restore, we now use fragment information from the
spilt-location-expression.
In addition, when spilling, we now don't spill any DBG_VALUE with a complex
expression, as it can't be safely restored and will definitely lead to an
incorrect variable location. The discussion of this is in D65368.
Differential Revision: https://reviews.llvm.org/D66284
llvm-svn: 369026
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Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
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