Commit Graph

412 Commits

Author SHA1 Message Date
Ivan Kosarev 86803008ea [MIR] Provide location of extra instruction operand when diagnosing it.
Also resolves misspelled FileCheck directives caught with D125604.

Reviewed By: foad

Differential Revision: https://reviews.llvm.org/D125965
2022-05-20 05:56:25 +01:00
Matt Arsenault 9c122537cd MIR: Serialize FunctionContextIdx in MachineFrameInfo 2022-04-22 11:07:41 -04:00
Matt Arsenault b8033de063 MIR: Serialize a few bool function fields 2022-04-15 20:31:07 -04:00
Matt Arsenault ced1250b0f MIRParser: Fix asserting with invalid flags on machine operands
Constructing an operand with kills on defs and deads on uses asserts
in the constructor, so diagnose these.
2022-04-05 21:46:26 -04:00
serge-sans-paille 02c28970b2 Cleanup include: codegen second round
Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D122180
2022-03-23 13:54:00 +01:00
serge-sans-paille ed98c1b376 Cleanup includes: DebugInfo & CodeGen
Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D121332
2022-03-12 17:26:40 +01:00
Mircea Trofin cb2160760e [nfc][codegen] Move RegisterBank[Info].h under CodeGen
This wraps up from D119053. The 2 headers are moved as described,
fixed file headers and include guards, updated all files where the old
paths were detected (simple grep through the repo), and `clang-format`-ed it all.

Differential Revision: https://reviews.llvm.org/D119876
2022-03-01 21:53:25 -08:00
Jay Foad 719bac55df [MIRParser] Diagnose too large align values in MachineMemOperands
When parsing MachineMemOperands, MIRParser treated the "align" keyword
the same as "basealign". Really "basealign" should specify the
alignment of the MachinePointerInfo base value, and "align" should
specify the alignment of that base value plus the offset.

This worked OK when the specified alignment was no larger than the
alignment of the offset, but in cases like this it just caused
confusion:

    STW killed %18, 4, %stack.1.ap2.i.i :: (store (s32) into %stack.1.ap2.i.i + 4, align 8)

MIRPrinter would never have printed this, with an offset of 4 but an
align of 8, so it must have been written by hand. MIRParser would
interpret "align 8" as "basealign 8", but I think it is better to give
an error and force the user to write "basealign 8" if that is what they
really meant.

Differential Revision: https://reviews.llvm.org/D120400

Change-Id: I7eeeefc55c2df3554ba8d89f8809a2f45ada32d8
2022-02-24 15:32:08 +00:00
Matt Arsenault 9c7ca51b2c MIR: Start diagnosing too many operands on an instruction
Previously this would just assert which was annoying and didn't point
to the specific instruction/operand.
2022-02-21 10:36:39 -05:00
Kazu Hirata 3a8c51480f [CodeGen] Use = default (NFC)
Identified with modernize-use-equals-default
2022-02-06 10:54:44 -08:00
Sebastian Neubauer f4139440f1 [Docs] Fix IR and TableGen grammar inconsistencies
IR:
- globals (and functions, ifuncs, aliases) can have a partition
- catchret has a `to` before the label
- the sint/int types do not exist
- signext comes after the type
- a variable was missing its type

TableGen:
- The second value after a `#` concatenation is optional
  See e.g. llvm/lib/Target/X86/X86InstrAVX512.td:L3351
- IncludeDirective and PreprocessorDirective were never referenced in
  the grammar
- Add some missing ;
- Parent classes of multiclasses can have generic arguments.
  Reuse the `ParentClassList` that is already used in other places.

MIR:
- liveins only allows physical registers, which start with a $

Differential Revision: https://reviews.llvm.org/D116674
2022-01-13 11:55:13 +01:00
Kazu Hirata b932bdf59f [llvm] Remove redundant member initialization (NFC)
Identified with readability-redundant-member-init.
2022-01-07 17:45:09 -08:00
Kazu Hirata e5947760c2 Revert "[llvm] Remove redundant member initialization (NFC)"
This reverts commit fd4808887e.

This patch causes gcc to issue a lot of warnings like:

  warning: base class ‘class llvm::MCParsedAsmOperand’ should be
  explicitly initialized in the copy constructor [-Wextra]
2022-01-03 11:28:47 -08:00
Kazu Hirata fd4808887e [llvm] Remove redundant member initialization (NFC)
Identified with readability-redundant-member-init.
2022-01-01 16:18:18 -08:00
Kai Luo b206ee6906 [MachineVerifier] Make TiedOpsRewritten computable in MIRParser
This patch is to address post-commit comment https://reviews.llvm.org/D80538#anchor-inline-1091625, which make the constraint stronger based on what https://reviews.llvm.org/D80538 does, i.e., "TiedOpsRewritten is set iff leave-ssa and all tied operands share the same register".

Reviewed By: MatzeB

Differential Revision: https://reviews.llvm.org/D114573
2021-12-07 02:25:15 +00:00
Jack Andersen f108c7f59d [GlobalISel] Allow DBG_VALUE to use undefined vregs before LiveDebugValues.
Expanding on D109750.

Since `DBG_VALUE` instructions have final register validity determined in
`LDVImpl::handleDebugValue`, there is no apparent reason to immediately prune
unused register operands as their defs are erased. Consequently, this renders
`MachineInstr::eraseFromParentAndMarkDBGValuesForRemoval` moot; gaining a
substantial performance improvement.

The only necessary changes involve making relevant passes consider invalid
DBG_VALUE vregs uses as valid.

Reviewed By: MatzeB

Differential Revision: https://reviews.llvm.org/D112852
2021-12-05 15:55:59 -05:00
Arthur Eubanks 05963a3d66 Revert "[DebugInfo] Enforce implicit constraints on `distinct` MDNodes"
This reverts commit ee76525698.

Causes crashes, see comments in D104827.
2021-11-09 14:27:55 -08:00
Scott Linder ee76525698 [DebugInfo] Enforce implicit constraints on `distinct` MDNodes
Add UNIQUED and DISTINCT properties in Metadata.def and use them to
implement restrictions on the `distinct` property of MDNodes:

* DIExpression can currently be parsed from IR or read from bitcode
  as `distinct`, but this property is silently dropped when printing
  to IR. This causes accepted IR to fail to round-trip. As DIExpression
  appears inline at each use in the canonical form of IR, it cannot
  actually be `distinct` anyway, as there is no syntax to describe it.
* Similarly, DIArgList is conceptually always uniqued. It is currently
  restricted to only appearing in contexts where there is no syntax for
  `distinct`, but for consistency it is treated equivalently to
  DIExpression in this patch.
* DICompileUnit is already restricted to always being `distinct`, but
  along with adding general support for the inverse restriction I went
  ahead and described this in Metadata.def and updated the parser to be
  general. Future nodes which have this restriction can share this
  support.

The new UNIQUED property applies to DIExpression and DIArgList, and
forbids them to be `distinct`. It also implies they are canonically
printed inline at each use, rather than via MDNode ID.

The new DISTINCT property applies to DICompileUnit, and requires it to
be `distinct`.

A potential alternative change is to forbid the non-inline syntax for
DIExpression entirely, as is done with DIArgList implicitly by requiring
it appear in the context of a function. For example, we would forbid:

    !named = !{!0}
    !0 = !DIExpression()

Instead we would only accept the equivalent inlined version:

    !named = !{!DIExpression()}

This essentially removes the ability to create a `distinct` DIExpression
by construction, as there is no syntax for `distinct` inline. If this
patch is accepted as-is, the result would be that the non-canonical
version is accepted, but the following would be an error and produce a diagnostic:

    !named = !{!0}
    ; error: 'distinct' not allowed for !DIExpression()
    !0 = distinct !DIExpression()

Also update some documentation to consistently use the inline syntax for
DIExpression, and to describe the restrictions on `distinct` for nodes
where applicable.

Reviewed By: StephenTozer, t-tye

Differential Revision: https://reviews.llvm.org/D104827
2021-11-09 18:19:11 +00:00
Jay Foad 36deb9a670 Add new MachineFunction property FailsVerification
TargetPassConfig::addPass takes a "bool verifyAfter" argument which lets
you skip machine verification after a particular pass. Unfortunately
this is used in generic code in TargetPassConfig itself to skip
verification after a generic pass, only because some previous target-
specific pass damaged the MIR on that specific target. This is bad
because problems in one target cause lack of verification for all
targets.

This patch replaces that mechanism with a new MachineFunction property
called "FailsVerification" which can be set by (usually target-specific)
passes that are known to introduce problems. Later passes can reset it
again if they are known to clean up the previous problems.

Differential Revision: https://reviews.llvm.org/D111397
2021-10-18 10:26:46 +01:00
Jay Foad 548b01c7a6 [MIRParser] Add support for IsInlineAsmBrIndirectTarget
Print this basic block flag as inlineasm-br-indirect-target and parse
it. This allows you to write MIR test cases for INLINEASM_BR. The test
case I added is one that I wanted to precommit anyway for D110834.

Differential Revision: https://reviews.llvm.org/D111291
2021-10-07 19:08:01 +01:00
Jack Andersen bd4dad87f4 [MachineInstr] Move MIParser's DBG_VALUE RegState::Debug invariant into MachineInstr::addOperand
Based on the reasoning of D53903, register operands of DBG_VALUE are
invariably treated as RegState::Debug operands. This change enforces
this invariant as part of MachineInstr::addOperand so that all passes
emit this flag consistently.

RegState::Debug is inconsistently set on DBG_VALUE registers throughout
LLVM. This runs the risk of a filtering iterator like
MachineRegisterInfo::reg_nodbg_iterator to process these operands
erroneously when not parsed from MIR sources.

This issue was observed in the development of the llvm-mos fork which
adds a backend that relies on physical register operands much more than
existing targets. Physical RegUnit 0 has the same numeric encoding as
$noreg (indicating an undef for DBG_VALUE). Allowing debug operands into
the machine scheduler correlates $noreg with RegUnit 0 (i.e. a collision
of register numbers with different zero semantics). Eventually, this
causes an assert where DBG_VALUE instructions are prohibited from
participating in live register ranges.

Reviewed By: MatzeB, StephenTozer

Differential Revision: https://reviews.llvm.org/D110105
2021-10-07 16:08:52 +01:00
Arthur Eubanks 05392466f0 Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 13:29:23 -07:00
Arthur Eubanks 569346f274 Revert "Reland [IR] Increase max alignment to 4GB"
This reverts commit 8d64314ffe.
2021-10-06 11:38:11 -07:00
Arthur Eubanks 8d64314ffe Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 11:03:51 -07:00
Arthur Eubanks 72cf8b6044 Revert "[IR] Increase max alignment to 4GB"
This reverts commit df84c1fe78.

Breaks some bots
2021-10-06 10:21:35 -07:00
Arthur Eubanks df84c1fe78 [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 09:54:14 -07:00
Jonas Devlieghere 52b5491a21 Revert "[DebugInfo] Enforce implicit constraints on `distinct` MDNodes"
This reverts commit 8cd35ad854.

It breaks `TestMembersAndLocalsWithSameName.py` on GreenDragon and
Mikael Holmén points out in D104827 that bitcode files created with the
patch cannot be parsed with binaries built before it.
2021-07-02 15:57:07 -07:00
Jeremy Morse 47c3fe2a22 [DebugInfo][InstrRef][1/4] Support transformations that widen values
Very late in compilation, backends like X86 will perform optimisations like
this:

    $cx = MOV16rm $rax, ...
    ->
    $rcx = MOV64rm $rax, ...

Widening the load from 16 bits to 64 bits. SEeing how the lower 16 bits
remain the same, this doesn't affect execution. However, any debug
instruction reference to the defined operand now refers to a 64 bit value,
nto a 16 bit one, which might be unexpected. Elsewhere in codegen, there's
often this pattern:

    CALL64pcrel32 @foo, implicit-def $rax
    %0:gr64 = COPY $rax
    %1:gr32 = COPY %0.sub_32bit

Where we want to refer to the definition of $eax by the call, but don't
want to refer the copies (they don't define values in the way
LiveDebugValues sees it). To solve this, add a subregister field to the
existing "substitutions" facility, so that we can describe a field within
a larger value definition. I would imagine that this would be used most
often when a value is widened, and we need to refer to the original,
narrower definition.

Differential Revision: https://reviews.llvm.org/D88891
2021-07-01 11:19:27 +01:00
Matt Arsenault fae05692a3 CodeGen: Print/parse LLTs in MachineMemOperands
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.
2021-06-30 16:54:13 -04:00
Michael Liao e818eface8 [MIRParser] Add machine metadata.
- Add standalone metadata parsing support so that machine metadata nodes
  could be populated before and accessed during MIR is parsed.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D103282
2021-06-28 22:29:36 -04:00
Scott Linder 8cd35ad854 [DebugInfo] Enforce implicit constraints on `distinct` MDNodes
Add UNIQUED and DISTINCT properties in Metadata.def and use them to
implement restrictions on the `distinct` property of MDNodes:

* DIExpression can currently be parsed from IR or read from bitcode
  as `distinct`, but this property is silently dropped when printing
  to IR. This causes accepted IR to fail to round-trip. As DIExpression
  appears inline at each use in the canonical form of IR, it cannot
  actually be `distinct` anyway, as there is no syntax to describe it.
* Similarly, DIArgList is conceptually always uniqued. It is currently
  restricted to only appearing in contexts where there is no syntax for
  `distinct`, but for consistency it is treated equivalently to
  DIExpression in this patch.
* DICompileUnit is already restricted to always being `distinct`, but
  along with adding general support for the inverse restriction I went
  ahead and described this in Metadata.def and updated the parser to be
  general. Future nodes which have this restriction can share this
  support.

The new UNIQUED property applies to DIExpression and DIArgList, and
forbids them to be `distinct`. It also implies they are canonically
printed inline at each use, rather than via MDNode ID.

The new DISTINCT property applies to DICompileUnit, and requires it to
be `distinct`.

A potential alternative change is to forbid the non-inline syntax for
DIExpression entirely, as is done with DIArgList implicitly by requiring
it appear in the context of a function. For example, we would forbid:

    !named = !{!0}
    !0 = !DIExpression()

Instead we would only accept the equivalent inlined version:

    !named = !{!DIExpression()}

This essentially removes the ability to create a `distinct` DIExpression
by construction, as there is no syntax for `distinct` inline. If this
patch is accepted as-is, the result would be that the non-canonical
version is accepted, but the following would be an error and produce a diagnostic:

    !named = !{!0}
    ; error: 'distinct' not allowed for !DIExpression()
    !0 = distinct !DIExpression()

Also update some documentation to consistently use the inline syntax for
DIExpression, and to describe the restrictions on `distinct` for nodes
where applicable.

Reviewed By: StephenTozer, t-tye

Differential Revision: https://reviews.llvm.org/D104827
2021-06-28 21:20:04 +00:00
Sander de Smalen d5e14ba88c [GlobalISel] NFC: Change LLT::vector to take ElementCount.
This also adds new interfaces for the fixed- and scalable case:
* LLT::fixed_vector
* LLT::scalable_vector

The strategy for migrating to the new interfaces was as follows:
* If the new LLT is a (modified) clone of another LLT, taking the
  same number of elements, then use LLT::vector(OtherTy.getElementCount())
  or if the number of elements is halfed/doubled, it uses .divideCoefficientBy(2)
  or operator*. That is because there is no reason to specifically restrict
  the types to 'fixed_vector'.
* If the algorithm works on the number of elements (as unsigned), then
  just use fixed_vector. This will need to be fixed up in the future when
  modifying the algorithm to also work for scalable vectors, and will need
  then need additional tests to confirm the behaviour works the same for
  scalable vectors.
* If the test used the '/*Scalable=*/true` flag of LLT::vector, then
  this is replaced by LLT::scalable_vector.

Reviewed By: aemerson

Differential Revision: https://reviews.llvm.org/D104451
2021-06-24 11:26:12 +01:00
RamNalamothu 167e7afcd5 Implement DW_CFA_LLVM_* for Heterogeneous Debugging
Add support in MC/MIR for writing/parsing, and DebugInfo.

This is part of the Extensions for Heterogeneous Debugging defined at
https://llvm.org/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html

Specifically the CFI instructions implemented here are defined at
https://llvm.org/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html#cfa-definition-instructions

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D76877
2021-06-14 08:51:50 +05:30
Jonathan Crowther e71994a239 [SystemZ][z/OS] Add IsText Argument to GetFile and GetFileOrSTDIN
Add the `IsText` argument to `GetFile` and `GetFileOrSTDIN` which will help z/OS distinguish between text and binary correctly. This is an extension to [this patch](https://reviews.llvm.org/D97785)

Reviewed By: abhina.sreeskantharajan, amccarth

Differential Revision: https://reviews.llvm.org/D100488
2021-04-16 10:08:36 -04:00
Matt Arsenault 20a24af01d MIR: Fix missing serialization for HasTailCall 2021-03-21 13:14:04 -04:00
Daniel Sanders 134a179dee [mir] Change 'undef' for MMO base addresses to 'unknown-address'
Differential Revision: https://reviews.llvm.org/D98100
2021-03-10 16:46:44 -08:00
Stephen Tozer f677413071 Reapply "[DebugInfo] Add new instruction and DIExpression operator for variadic debug values"
Rewrites test to use correct architecture triple; fixes incorrect
reference in SourceLevelDebugging doc; simplifies `spillReg` behaviour
so as to not be dependent on changes elsewhere in the patch stack.

This reverts commit d2000b45d0.
2021-03-05 12:32:05 +00:00
Daniel Sanders 9fc2be6f28 [mir] Fix confusing MIR when MMO's value is nullptr but offset is non-zero
:: (store 1 + 4, addrspace 1)
->
:: (store 1 into undef + 4, addrspace 1)

An offset without a base isn't terribly useful but it's convenient to update
the offset without checking the value. For example, when breaking apart
stores into smaller units

Differential Revision: https://reviews.llvm.org/D97812
2021-03-04 10:34:30 -08:00
Stephen Tozer d2000b45d0 Revert "[DebugInfo] Add new instruction and DIExpression operator for variadic debug values"
This reverts commit d07f106f4a.
2021-03-04 11:59:21 +00:00
gbtozers d07f106f4a [DebugInfo] Add new instruction and DIExpression operator for variadic debug values
This patch adds a new instruction that can represent variadic debug values,
DBG_VALUE_VAR. This patch alone covers the addition of the instruction and a set
of basic code changes in MachineInstr and a few adjacent areas, but does not
correctly handle variadic debug values outside of these areas, nor does it
generate them at any point.

The new instruction is similar to the existing DBG_VALUE instruction, with the
following differences: the operands are in a different order, any number of
values may be used in the instruction following the Variable and Expression
operands (these are referred to in code as “debug operands”) and are indexed
from 0 so that getDebugOperand(X) == getOperand(X+2), and the Expression in a
DBG_VALUE_VAR must use the DW_OP_LLVM_arg operator to pass arguments into the
expression.

The new DW_OP_LLVM_arg operator is only valid in expressions appearing in a
DBG_VALUE_VAR; it takes a single argument and pushes the debug operand at the
index given by the argument onto the Expression stack. For example the
sub-expression `DW_OP_LLVM_arg, 0` has the meaning “Push the debug operand at
index 0 onto the expression stack.”

Differential Revision: https://reviews.llvm.org/D82363
2021-03-04 11:45:35 +00:00
Matt Arsenault 2d3d2e78d0 MIR: Fix parser crash on syntax error on first character
This was calling the diagnostic printer before the context member was
initialized.
2021-02-18 18:59:08 -05:00
Kazu Hirata 22f00f61dd [CodeGen] Use range-based for loops (NFC) 2021-02-15 14:46:11 -08:00
Craig Topper b1c304c494 [CodeGen] Try to make the print of memory operand alignment a little more user friendly.
Memory operands store a base alignment that does not factor in
the effect of the offset on the alignment.

Previously the printing code only printed the base alignment if
it was different than the size. If there is an offset, the reader
would need to figure out the effective alignment themselves. This
has confused me before and someone else was recently confused on
IRC.

This patch prints the possibly offset adjusted alignment if it is
different than the size. And prints the base alignment if it is
different than the alignment. The MIR parser has been updated to
read basealign in addition to align.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D94344
2021-01-11 19:58:47 -08:00
Kazu Hirata 789d250613 [CodeGen, Transforms] Use *Map::lookup (NFC) 2020-12-27 09:57:27 -08:00
serge-sans-paille 9218ff50f9 llvmbuildectomy - replace llvm-build by plain cmake
No longer rely on an external tool to build the llvm component layout.

Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.

These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.

Differential Revision: https://reviews.llvm.org/D90848
2020-11-13 10:35:24 +01:00
Jeremy Morse c521e44def [DebugInstrRef] Support recording of instruction reference substitutions
Add a table recording "substitutions" between pairs of <instruction,
operand> numbers, from old pairs to new pairs. Post-isel optimizations are
able to record the outcome of an optimization in this way. For example, if
there were a divide instruction that generated the quotient and remainder,
and it were replaced by one that only generated the quotient:

  $rax, $rcx = DIV-AND-REMAINDER $rdx, $rsi, debug-instr-num 1
  DBG_INSTR_REF 1, 0
  DBG_INSTR_REF 1, 1

Became:

  $rax = DIV $rdx, $rsi, debug-instr-num 2
  DBG_INSTR_REF 1, 0
  DBG_INSTR_REF 1, 1

We could enter a substitution from <1, 0> to <2, 0>, and no substitution
for <1, 1> as it's no longer generated.

This approach means that if an instruction or value is deleted once we've
left SSA form, all variables that used the value implicitly become
"optimized out", something that isn't true of the current DBG_VALUE
approach.

Differential Revision: https://reviews.llvm.org/D85749
2020-10-15 11:30:14 +01:00
Jeremy Morse 2c5f3d54c5 [DebugInstrRef] Parse debug instruction-references from/to MIR
This patch defines the MIR format for debug instruction references: it's an
integer trailing an instruction, marked out by "debug-instr-number", much
like how "debug-location" identifies the DebugLoc metadata of an
instruction. The instruction number is stored directly in a MachineInstr.

Actually referring to an instruction comes in a later patch, but is done
using one of these instruction numbers.

I've added a round-trip test and two verifier checks: that we don't label
meta-instructions as generating values, and that there are no duplicates.

Differential Revision: https://reviews.llvm.org/D85746
2020-10-14 10:57:09 +01:00
Scott Linder 4a98cf7867 [NFC] Reformat MILexer.cpp:getIdentifierKind
Reformat to avoid unrelated changes in diff of future patch.
Committed as obvious.
2020-10-09 15:21:24 +00:00
Rahman Lavaee 7841e21c98 Let -basic-block-sections=labels emit basicblock metadata in a new .bb_addr_map section, instead of emitting special unary-encoded symbols.
This patch introduces the new .bb_addr_map section feature which allows us to emit the bits needed for mapping binary profiles to basic blocks into a separate section.
The format of the emitted data is represented as follows. It includes a header for every function:

|  Address of the function                      |  -> 8 bytes (pointer size)
|  Number of basic blocks in this function (>0) |  -> ULEB128

The header is followed by a BB record for every basic block. These records are ordered in the same order as MachineBasicBlocks are placed in the function. Each BB Info is structured as follows:

|  Offset of the basic block relative to function begin |  -> ULEB128
|  Binary size of the basic block                       |  -> ULEB128
|  BB metadata                                          |  -> ULEB128  [ MBB.isReturn() OR MBB.hasTailCall() << 1  OR  MBB.isEHPad() << 2 ]

The new feature will replace the existing "BB labels" functionality with -basic-block-sections=labels.
The .bb_addr_map section scrubs the specially-encoded BB symbols from the binary and makes it friendly to profilers and debuggers.
Furthermore, the new feature reduces the binary size overhead from 70% bloat to only 12%.

For more information and results please refer to the RFC: https://lists.llvm.org/pipermail/llvm-dev/2020-July/143512.html

Reviewed By: MaskRay, snehasish

Differential Revision: https://reviews.llvm.org/D85408
2020-09-14 10:16:44 -07:00
Sander de Smalen f13beac51b [AArch64][SVE] Preserve full vector regs over EH edge.
Unwinders may only preserve the lower 64bits of Neon and SVE registers,
as only the registers in the base ABI are guaranteed to be preserved
over the exception edge. The caller will need to preserve additional
registers for when the call throws an exception and the unwinder has
tried to recover state.

For  e.g.

    svint32_t bar(svint32_t);
    svint32_t foo(svint32_t x, bool *err) {
      try { bar(x); } catch (...) { *err = true; }
      return x;
    }

`z0` needs to be spilled before the call to `bar(x)` and reloaded before
returning from foo, as the exception handler may have clobbered z0.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D84737
2020-09-02 10:54:18 +01:00