This commits changes the definition of spv.module to use the #spv.vce
attribute for specifying (version, capabilities, extensions) triple
so that we can have better API and custom assembly form. Since now
we have proper modelling of the triple, (de)serialization is wired up
to use them.
With the new UpdateVCEPass, we don't need to manually specify the
required extensions and capabilities anymore when creating a spv.module.
One just need to call UpdateVCEPass before serialization to get the
needed version/extensions/capabilities.
Differential Revision: https://reviews.llvm.org/D75872
This commit updates SPIR-V dialect to support integer signedness
by relaxing various checks for signless to just normal integers.
The hack for spv.Bitcast can now be removed.
Differential Revision: https://reviews.llvm.org/D75611
Thus far IntegerType has been signless: a value of IntegerType does
not have a sign intrinsically and it's up to the specific operation
to decide how to interpret those bits. For example, std.addi does
two's complement arithmetic, and std.divis/std.diviu treats the first
bit as a sign.
This design choice was made some time ago when we did't have lots
of dialects and dialects were more rigid. Today we have much more
extensible infrastructure and different dialect may want different
modelling over integer signedness. So while we can say we want
signless integers in the standard dialect, we cannot dictate for
others. Requiring each dialect to model the signedness semantics
with another set of custom types is duplicating the functionality
everywhere, considering the fundamental role integer types play.
This CL extends the IntegerType with a signedness semantics bit.
This gives each dialect an option to opt in signedness semantics
if that's what they want and helps code sharing. The parser is
modified to recognize `si[1-9][0-9]*` and `ui[1-9][0-9]*` as
signed and unsigned integer types, respectively, leaving the
original `i[1-9][0-9]*` to continue to mean no indication over
signedness semantics. All existing dialects are not affected (yet)
as this is a feature to opt in.
More discussions can be found at:
https://groups.google.com/a/tensorflow.org/d/msg/mlir/XmkV8HOPWpo/7O4X0Nb_AQAJ
Differential Revision: https://reviews.llvm.org/D72533
Thus far we have been using builtin func op to model SPIR-V functions.
It was because builtin func op used to have special treatment in
various parts of the core codebase (e.g., pass pipelines, etc.) and
it's easy to bootstrap the development of the SPIR-V dialect. But
nowadays with general op concepts and region support we don't have
such limitations and it's time to tighten the SPIR-V dialect for
completeness.
This commits introduces a spv.func op to properly model SPIR-V
functions. Compared to builtin func op, it can provide the following
benefits:
* We can control the full op so we can integrate SPIR-V information
bits (e.g., function control) in a more integrated way and define
our own assembly form and enforcing better verification.
* We can have a better dialect and library boundary. At the current
moment only functions are modelled with an external op. With this
change, all ops modelling SPIR-V concpets will be spv.* ops and
registered to the SPIR-V dialect.
* We don't need to special-case func op anymore when creating
ConversionTarget declaring SPIR-V dialect as legal. This is quite
important given we'll see more and more conversions in the future.
In the process, bumps a few FuncOp methods to the FunctionLike trait.
Differential Revision: https://reviews.llvm.org/D74226
This is an initial step to refactoring the representation of OpResult as proposed in: https://groups.google.com/a/tensorflow.org/g/mlir/c/XXzzKhqqF_0/m/v6bKb08WCgAJ
This change will make it much simpler to incrementally transition all of the existing code to use value-typed semantics.
PiperOrigin-RevId: 286844725
The iterator should be erased before adding a new entry
into blockMergeInfo to avoid iterator invalidation.
Closestensorflow/mlir#299
COPYBARA_INTEGRATE_REVIEW=https://github.com/tensorflow/mlir/pull/299 from denis0x0D:sandbox/reoder_erase 983be565809aa0aadfc7e92962e4d4b282f63c66
PiperOrigin-RevId: 284173235
For serialization, when we have nested ops, the inner loop will create multiple
SPIR-V blocks. If the outer loop has block arguments (which corresponds to
OpPhi instructions), we defer the handling of OpPhi's parent block handling
until we serialized all blocks and then fix it up with the result <id>. These two
cases happening together was generating invalid SPIR-V blob because we
previously assume the parent block to be the block containing the terminator.
That is not true anymore when the block contains structured control flow ops.
If that happens, it should be fixed to use the structured control flow op's
merge block.
For deserialization, we record a map from header blocks to their corresponding
merge and continue blocks during the initial deserialization and then use the
info to construct spv.selection/spv.loop. The existing implementation will also
fall apart when we have nested loops. If so, we clone all blocks for the outer
loop, including the ones for the inner loop, to the spv.loop's region. So the map
for header blocks' merge info need to be updated; otherwise we are operating
on already deleted blocks.
PiperOrigin-RevId: 283949230
During deserialization, the loop header block will be moved into the
spv.loop's region. If the loop header block has block arguments,
we need to make sure it is correctly carried over to the block where
the new spv.loop resides.
During serialization, we need to make sure block arguments from the
spv.loop's entry block are not silently dropped.
PiperOrigin-RevId: 280021777
This change allows for adding additional nested references to a SymbolRefAttr to allow for further resolving a symbol if that symbol also defines a SymbolTable. If a referenced symbol also defines a symbol table, a nested reference can be used to refer to a symbol within that table. Nested references are printed after the main reference in the following form:
symbol-ref-attribute ::= symbol-ref-id (`::` symbol-ref-id)*
Example:
module @reference {
func @nested_reference()
}
my_reference_op @reference::@nested_reference
Given that SymbolRefAttr is now more general, the existing functionality centered around a single reference is moved to a derived class FlatSymbolRefAttr. Followup commits will add support to lookups, rauw, etc. for scoped references.
PiperOrigin-RevId: 279860501
This CL adds another control flow instruction in SPIR-V: OpPhi.
It is modelled as block arguments to be idiomatic with MLIR.
See the rationale.md doc for "Block Arguments vs PHI nodes".
Serialization and deserialization is updated to convert between
block arguments and SPIR-V OpPhi instructions.
PiperOrigin-RevId: 277161545
We will use block arguments as the way to model SPIR-V OpPhi in
the SPIR-V dialect.
This CL also adds a few useful helper methods to both ops to
get the block arguments.
Also added tests for branch weight (de)serialization.
PiperOrigin-RevId: 275960797
The SpecId decoration is the handle for providing external specialization.
Similar to descriptor set and binding on global variables, we directly
bake it into assembly parsing and printing.
PiperOrigin-RevId: 274893879
Since MLIR integer types don't make a distinction between signed vs
unsigned integers, during deserialization of SPIR-V binaries, the
OpBitcast might result in a cast from/to the same type. Do not add a
spv.Bitcast operation to the spv.module in these cases.
PiperOrigin-RevId: 273381887
The SPIR-V spec recommends all OpUndef instructions be generated at
module level. For the SPIR-V dialect its better for UndefOp to produce
an SSA value for use with other instructions. If UndefOp is to be used
at module level, it cannot produce an SSA value (use of this SSA value
within FuncOp would need implicit capture). To satisfy needs of the
SPIR-V spec while making it simpler to represent UndefOp in the SPIR-V
dialect, the serialization is updated to create OpUndef instruction
at module scope.
PiperOrigin-RevId: 273355526
The structured selection/loop's entry block does not have arguments.
If the function's header block is also part of the structured control
flow, we cannot just simply erase it because it may contain arguments
matching the function signature and used by the cloned blocks. Instead,
turn it into a block only containing a spv.Branch op.
Also, we can directly emit instructions for the spv.selection header
block to the block containing the spv.selection op. This eliminates
unnecessary branches in the SPIR-V blob.
Added a test for nested spv.loop.
PiperOrigin-RevId: 273351424
Similar to spv.loop, spv.selection is another op for modelling
SPIR-V structured control flow. It covers both OpBranchConditional
and OpSwitch with OpSelectionMerge.
Instead of having a `spv.SelectionMerge` op to directly model
selection merge instruction for indicating the merge target,
we use regions to delimit the boundary of the selection: the
merge target is the next op following the `spv.selection` op.
This way it's easier to discover all blocks belonging to
the selection and it plays nicer with the MLIR system.
PiperOrigin-RevId: 272475006
1) Process and ignore the following debug instructions: OpSource,
OpSourceContinued, OpSourceExtension, OpString, OpModuleProcessed.
2) While processing OpTypeInt instruction, ignore the signedness
specification. Currently MLIR doesnt make a distinction between signed
and unsigned integer types.
3) Process and ignore BufferBlock decoration (similar to Buffer
decoration). StructType needs to be enhanced to track this attribute
since its needed for proper validation checks.
4) Report better error for unhandled instruction during
deserialization.
PiperOrigin-RevId: 271057060
Sdd support in deserializer for OpMemberName instruction. For now
the name is just processed and not associated with the
spirv::StructType being built. That needs an enhancement to
spirv::StructTypes itself.
Add tests to check for errors reported during deserialization with
some refactoring to common out some utility functions.
PiperOrigin-RevId: 270794524
The existing logic to parse spirv::StructTypes is very brittle. This
change simplifies the parsing logic a lot. The simplification also
allows for memberdecorations to be separated by commas instead of
spaces (which was an artifact of the existing parsing logic). The
change also needs a modification to mlir::parseType to return the
number of chars parsed. Adding a new parseType method to do so.
Also allow specification of spirv::StructType with no members.
PiperOrigin-RevId: 270739672
Allow specification of decorators on SPIR-V StructType members. If the
struct has layout information, these decorations are to be specified
after the offset specification of the member. These decorations are
emitted as OpMemberDecorate instructions on the struct <id>. Update
(de)serialization to handle these decorations.
PiperOrigin-RevId: 270130136
A generic mechanism for (de)serialization of extended instruction sets
is added with this CL. To facilitate this, a new class
"SPV_ExtendedInstSetOp" is added which is a base class for all
operations corresponding to extended instruction sets. The methods to
(de)serialization such ops as well as its dispatch is generated
automatically.
The behavior controlled by autogenSerialization and hasOpcode is also
slightly modified to enable this. They are now decoupled.
1) Setting hasOpcode=1 means the operation has a corresponding
opcode in SPIR-V binary format, and its dispatch for
(de)serialization is automatically generated.
2) Setting autogenSerialization=1 generates the function for
(de)serialization automatically.
So now it is possible to have hasOpcode=0 and autogenSerialization=1
(for example SPV_ExtendedInstSetOp).
Since the dispatch functions is also auto-generated, the input file
needs to contain all operations. To this effect, SPIRVGLSLOps.td is
included into SPIRVOps.td. This makes the previously added
SPIRVGLSLOps.h and SPIRVGLSLOps.cpp unnecessary, and are deleted.
The SPIRVUtilsGen.cpp is also changed to make better use of
formatv,making the code more readable.
PiperOrigin-RevId: 269456263
This CL adds support for serializing and deserializing spv.loop ops.
This adds support for spv.Branch and spv.BranchConditional op
(de)serialization, too, because they are needed for spv.loop.
PiperOrigin-RevId: 268536962
Each basic block in SPIR-V must start with an OpLabel instruction.
We don't support control flow yet, so this CL just makes sure that
the entry block follows this rule and is valid.
PiperOrigin-RevId: 265718841
In SPIR-V binary format, constants are placed at the module level
and referenced by instructions inside functions using their result
<id>s. To model this natively (using SSA values for result <id>s),
it means we need to have implicit capturing functions. We will
lose the ability to have function passes if going down that path.
Instead, this CL changes to materialize constants at their use
sites in deserialization. It's cheap to copy constants in MLIR
given that attributes is uniqued to MLIRContext. By localizing
constants into functions, we can preserve isolated functions.
PiperOrigin-RevId: 264582532
Similar to global variables, specialization constants also live
in the module scope and can be referenced by instructions in
functions in native SPIR-V. A direct modelling would be to allow
functions in the SPIR-V dialect to implicit capture, but it means
we are losing the ability to write passes for Functions. While
in SPIR-V normally we want to process the module as a whole,
it's not common to see multiple functions get used so we'd like
to leave the door open for those cases. Therefore, similar to
global variables, we introduce spv.specConstant to model three
SPIR-V instructions: OpSpecConstantTrue, OpSpecConstantFalse,
and OpSpecConstant. They do not return SSA value results;
instead they have symbols and can only be referenced by the
symbols. To use it in a function, we need to have another op
spv._reference_of to turn the symbol into an SSA value. This
breaks the tie and makes functions still explicit capture.
Previously specialization constants were handled similarly as
normal constants. That is incorrect given that specialization
constant actually acts more like variable (without need to
load and store). E.g., they cannot be de-duplicated like normal
constants.
This CL also refines various documents and comments.
PiperOrigin-RevId: 264455172
FuncOps in MLIR use explicit capture. So global variables defined in
module scope need to have a symbol name and this should be used to
refer to the variable within the function. This deviates from SPIR-V
spec, which assigns an SSA value to variables at all scopes that can
be used to refer to the variable, which requires SPIR-V functions to
allow implicit capture. To handle this add a new op,
spirv::GlobalVariableOp that can be used to define module scope
variables.
Since instructions need an SSA value, an new spirv::AddressOfOp is
added to convert a symbol reference to an SSA value for use with other
instructions.
This also means the spirv::EntryPointOp instruction needs to change to
allow initializers to be specified using symbol reference instead of
SSA value
The current spirv::VariableOp which returns an SSA value (as defined
by SPIR-V spec) can still be used to define function-scope variables.
PiperOrigin-RevId: 263951109
Generate the EnumAttr to represent BuiltIns in SPIR-V dialect. The
builtIn can be specified as a StringAttr with value being the
name of the builtin. Extend Decoration (de)serialization to handle
BuiltIns.
Also fix an error in the SPIR-V dialect generator script.
PiperOrigin-RevId: 263596624
This CL extends the existing spv.constant op to also support
specialization constant by adding an extra unit attribute
on it.
PiperOrigin-RevId: 261194869
All non-argument attributes specified for an operation are treated as
decorations on the result value and (de)serialized using OpDecorate
instruction. An error is generated if an attribute is not an argument,
and the name doesn't correspond to a Decoration enum. Name of the
attributes that represent decoerations are to be the snake-case-ified
version of the Decoration name.
Add utility methods to convert to snake-case and camel-case.
PiperOrigin-RevId: 260792638
