[DebugInfo] Let InstrRefBasedLDV handle joins for lists of debug ops

In preparation for adding support for DBG_VALUE_LIST instructions in
InstrRefLDV, this patch updates the logic for joining variab

[DebugInfo] Let InstrRefBasedLDV handle joins for lists of debug ops

In preparation for adding support for DBG_VALUE_LIST instructions in
InstrRefLDV, this patch updates the logic for joining variables at block
joins to support joining variables that use multiple debug operands.
This is one of the more meaty "logical" changes, although the line count
isn't too high - this changes pickVPHILoc to find a valid joined
location for every operand, with part of the function being split off
into pickValuePHILoc which finds a location for a single operand.

Differential Revision: https://reviews.llvm.org/D128180

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[DebugInfo][NFC] Represent DbgValues with multiple ops in IRefLDV

In preparation for allowing InstrRefBasedLDV to handle DBG_VALUE_LIST,
this patch updates the internal representation that it uses t

[DebugInfo][NFC] Represent DbgValues with multiple ops in IRefLDV

In preparation for allowing InstrRefBasedLDV to handle DBG_VALUE_LIST,
this patch updates the internal representation that it uses to represent
debug values to store a list of values. This is one of the more
significant changes in terms of line count, but is fairly simple and
should not affect the output of this pass.

Differential Revision: https://reviews.llvm.org/D128177

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[DebugInfo][NFC] Update LDV to use generic DBG_VALUE* MI interface

Currently, InstrRefLDV only handles DBG_VALUE instructions, not
DBG_VALUE_LIST, and as a result of this it handles these instructio

[DebugInfo][NFC] Update LDV to use generic DBG_VALUE* MI interface

Currently, InstrRefLDV only handles DBG_VALUE instructions, not
DBG_VALUE_LIST, and as a result of this it handles these instructions
using functions that only work for that type of debug value, i.e. using
getOperand(0) to get the debug operand. This patch changes this to use
the generic debug value functions, such as getDebugOperand and
isDebugOffsetImm, as well as adding an IsVariadic field to the
DbgValueProperties class and a few other minor changes to acknowledge
DBG_VALUE_LISTs. Note that this patch does not add support for
DBG_VALUE_LIST here, but is a precursor to other patches that do add
that support.

Differential Revision: https://reviews.llvm.org/D128174

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[DebugInfo] Handle joins PHI+Def values in InstrRef LiveDebugValues

In the InstrRefBasedImpl for LiveDebugValues, we attempt to propagate
debug values through basic blocks in part by checking to see

[DebugInfo] Handle joins PHI+Def values in InstrRef LiveDebugValues

In the InstrRefBasedImpl for LiveDebugValues, we attempt to propagate
debug values through basic blocks in part by checking to see whether all
a variable's incoming debug values to a BB "agree", i.e. whether their
properties match and they refer to the same underlying value.

Prior to this patch, the check for agreement between incoming values
relied on exact equality, which meant that a VPHI and a Def DbgValue
that referred to the same underlying value would be seen as disagreeing.
This patch changes this behaviour to treat them as referring to the same
value, allowing the shared value to propagate into the BB.

Differential Revision: https://reviews.llvm.org/D125953

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Remove redundant initialization of Optional (NFC)

LiveDebugValues: Fix another crash related to unreachable blocks

This is a follow-up patch to D130999. In the test, the MIR contains an
unreachable MBB but the code attempts to look it up in MLocs.

LiveDebugValues: Fix another crash related to unreachable blocks

This is a follow-up patch to D130999. In the test, the MIR contains an
unreachable MBB but the code attempts to look it up in MLocs. This
patch fixes this issue by checking for the default-constructed value.

rdar://97226240

Differential Revision: https://reviews.llvm.org/D131453

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[llvm] Fix comment typos (NFC)

Fix LDV InstrRefBasedImpl to not crash when encountering unreachable MBBs.

The testcase was delta-reduced from an LTO build with sanitizer
coverage and the MIR tail duplication pass caused a machine

Fix LDV InstrRefBasedImpl to not crash when encountering unreachable MBBs.

The testcase was delta-reduced from an LTO build with sanitizer
coverage and the MIR tail duplication pass caused a machine basic
block to become unreachable in MIR. This caused the MBB to be invisible
to the reverse post-order traversal used to initialize the MBB <->
RPONumber lookup tables.

rdar://97226240

Differential Revision: https://reviews.llvm.org/D130999

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Use llvm::less_first and llvm::less_second (NFC)

[CodeGen] Remove a redundant void (NFC)

Identified with modernize-redundant-void-arg.

Use llvm::sort instead of std::sort where possible

llvm::sort is beneficial even when we use the iterator-based overload,
since it can optionally shuffle the elements (to detect
non-determinism). Ho

Use llvm::sort instead of std::sort where possible

llvm::sort is beneficial even when we use the iterator-based overload,
since it can optionally shuffle the elements (to detect
non-determinism). However llvm::sort is not usable everywhere, for
example, in compiler-rt.

Reviewed By: nhaehnle

Differential Revision: https://reviews.llvm.org/D130406

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[CodeGen] Qualify auto variables in for loops (NFC)

[DebugInfo][InstrRef] Fix error in copy handling in InstrRefLDV

Currently, an error exists when InstrRefBasedLDV observes transfers of
variables across copies, which causes it to lose track of varia

[DebugInfo][InstrRef] Fix error in copy handling in InstrRefLDV

Currently, an error exists when InstrRefBasedLDV observes transfers of
variables across copies, which causes it to lose track of variables
under certain circumstances, resulting in shorter lifetimes for those
variables as LDV gives up searching for live locations for them. This
patch fixes this issue by storing the currently tracked values in
the destination first, then updating them manually later without
clobbering or assigning them the wrong value.

Differential Revision: https://reviews.llvm.org/D128101

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[CodeGen] Init EmptyExpr before the first use

[DebugInfo][InstrRef] Describe value sizes when spilt to stack

This is a re-apply of D123599, which was reverted in 4fe2ab5279408, now
with a more appropriate assertion. Original commit message foll

[DebugInfo][InstrRef] Describe value sizes when spilt to stack

This is a re-apply of D123599, which was reverted in 4fe2ab5279408, now
with a more appropriate assertion. Original commit message follow:

InstrRefBasedLDV can track and describe variable values that are spilt to
the stack -- however it does not current describe the size of the value on
the stack. This can cause uninitialized bytes to be read from the stack if
a small register is spilt for a larger variable, or theoretically on
big-endian machines if a large value on the stack is used for a small
variable.

Fix this by using DW_OP_deref_size to specify the amount of data to load
from the stack, if there's any possibility for ambiguity. There are a few
scenarios where this can be omitted (such as when using DW_OP_piece and a
non-DW_OP_stack_value location), see deref-spills-with-size.mir for an
explicit table of inputs flavours and output expressions.

Differential Revision: https://reviews.llvm.org/D123599

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Revert "[DebugInfo][InstrRef] Describe value sizes when spilt to stack"

This reverts commit a15b66e76d1ecff625a4bbb4a46ff83a43138f49.

This causes linker to crash at assertion: `Assertion failed: !E

Revert "[DebugInfo][InstrRef] Describe value sizes when spilt to stack"

This reverts commit a15b66e76d1ecff625a4bbb4a46ff83a43138f49.

This causes linker to crash at assertion: `Assertion failed: !Expr->isComplex(), file C:\b\s\w\ir\cache\builder\src\third_party\llvm\llvm\lib\CodeGen\LiveDebugValues\InstrRefBasedImpl.cpp, line 907`.

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[DebugInfo][InstrRef] Describe value sizes when spilt to stack

InstrRefBasedLDV can track and describe variable values that are spilt to
the stack -- however it does not current describe the size of

[DebugInfo][InstrRef] Describe value sizes when spilt to stack

InstrRefBasedLDV can track and describe variable values that are spilt to
the stack -- however it does not current describe the size of the value on
the stack. This can cause uninitialized bytes to be read from the stack if
a small register is spilt for a larger variable, or theoretically on
big-endian machines if a large value on the stack is used for a small
variable.

Fix this by using DW_OP_deref_size to specify the amount of data to load
from the stack, if there's any possibility for ambiguity. There are a few
scenarios where this can be omitted (such as when using DW_OP_piece and a
non-DW_OP_stack_value location), see deref-spills-with-size.mir for an
explicit table of inputs flavours and output expressions.

Differential Revision: https://reviews.llvm.org/D123599

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Reapply D124184, [DebugInfo][InstrRef] Add a size operand to DBG_PHI

This was reverted twice, in 987cd7c3ed75b and 13815e8cbf8d4. The latter
stemed from not accounting for rare register classes in a

Reapply D124184, [DebugInfo][InstrRef] Add a size operand to DBG_PHI

This was reverted twice, in 987cd7c3ed75b and 13815e8cbf8d4. The latter
stemed from not accounting for rare register classes in a pre-allocated
array, and the former from an array not being completely initialized,
leading to asan complaining.

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Revert "Reapply D124184, [DebugInfo][InstrRef] Add a size operand to DBG_PHI"

This reverts commit 5db925023169f8a19419e68153682d1e518f8392.

Further to the early revert, the sanitizers have found so

Revert "Reapply D124184, [DebugInfo][InstrRef] Add a size operand to DBG_PHI"

This reverts commit 5db925023169f8a19419e68153682d1e518f8392.

Further to the early revert, the sanitizers have found something wrong with
this.

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Reapply D124184, [DebugInfo][InstrRef] Add a size operand to DBG_PHI

This was applied in fda4305e53784, reverted in 13815e8cbf8d49, the problem
was that fp80 X86 registers that were spilt to the sta

Reapply D124184, [DebugInfo][InstrRef] Add a size operand to DBG_PHI

This was applied in fda4305e53784, reverted in 13815e8cbf8d49, the problem
was that fp80 X86 registers that were spilt to the stack aren't expected by
LiveDebugValues. It pre-allocates a position number for all register sizes
that can be spilt, and 80 bits isn't exactly common.

The solution is to scan the register classes to find any unrecognised
register sizes, adn pre-allocate those position numbers, avoiding a later
assertion.

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Revert "[DebugInfo][InstrRef] Add a size operand to DBG_PHI"

This reverts commit fda4305e5378478051be225248bfe9c1d401d938.

Green dragon has spotted a problem -- it's understood, but might be fiddly

Revert "[DebugInfo][InstrRef] Add a size operand to DBG_PHI"

This reverts commit fda4305e5378478051be225248bfe9c1d401d938.

Green dragon has spotted a problem -- it's understood, but might be fiddly
to fix, reverting in the meantime.

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[DebugInfo][InstrRef] Add a size operand to DBG_PHI

DBG_PHI instructions can refer to stack slots, to indicate that multiple
values merge together on control flow joins in that slot. This is fine --

[DebugInfo][InstrRef] Add a size operand to DBG_PHI

DBG_PHI instructions can refer to stack slots, to indicate that multiple
values merge together on control flow joins in that slot. This is fine --
however the slot might be merged at a later date with a slot of a different
size. In doing so, we lose information about the size the eliminated PHI.
Later analysis passes have to guess.

Improve this by attaching an optional "bit size" operand to DBG_PHI, which
only gets added for stack slots, to let us know how large a size the value
on the stack is.

Differential Revision: https://reviews.llvm.org/D124184

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[DebugInfo][InstrRef] Prefer stack locations for variables

This patch adjusts what location is picked for a known variable value --
preferring to leave locations on the stack, even when a value is r

[DebugInfo][InstrRef] Prefer stack locations for variables

This patch adjusts what location is picked for a known variable value --
preferring to leave locations on the stack, even when a value is re-loaded
into a register. The benefit is reduced location list entropy, on a
clang-3.4 build I found that .debug_loclists reduces in size by 6%, from
29Mb down to 27Mb.

Testing: a few tests need the stack slot to be written to explicitly, to
force LiveDebugValues into restoring the variable location to a register.
I've added an explicit test for the desired behaviour in
livedebugvalues_recover_clobbers.mir .

Differential Revision: https://reviews.llvm.org/D120732

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Cleanup codegen includes

This is a (fixed) recommit of https://reviews.llvm.org/D121169

after: 1061034926
before: 1063332844

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-in

Cleanup codegen includes

This is a (fixed) recommit of https://reviews.llvm.org/D121169

after: 1061034926
before: 1063332844

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D121681

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Revert "Cleanup codegen includes"

This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https:/

Revert "Cleanup codegen includes"

This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https://reviews.llvm.org/D121169

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