SPIR-V Tools

Overview

The project includes an assembler, disassembler, and validator for SPIR-V, all based on a common static library. The library contains all of the implementation details and is used in the standalone tools whilst also enabling integration into other code bases directly.

Supported features

Assembler and disassembler

• Based on SPIR-V 0.99 Revision 32
  • Supports core instructions and enumerants from Rev 32.
• All GLSL std450 extended instructions are supported.
• Assembler only does basic syntax checking. No cross validation of IDs or types is performed, except to check literal arguments to OpConstant, OpSpecConstant, and OpSwitch.
• OpenCL extended instructions are supported, from version 1.0 Revision 1.

Validator

The validator is incomplete. See the Future Work section for more information.

CHANGES (for tools hackers)

2015-10-16

• OpenCL extended instructions are supported, from version 1.0 Revision 1.
• Capability dependencies for instructions and enums now match 0.99 Rev 32.
• Very long instructions are supported, up to SPIR-V universal limits.
• UTF-8 literal strings are supported.
• Assembler support for numeric literals:
  • 32 and 64-bit floating point literals are encoded properly.
  • Signed and unsigned integers of any width up to 64 bits are supported and encoded properly.
  • Hexadecimal literals are supported. See syntax.md.
  • Numeric literal arguments to OpConstant, OpSpecConstant, and OpSwitch are type- and range-checked. The assembler checks that other literal numbers are non-negative integers. That's the grammar works, at least for now.

2015-10-02

• Completed assembler support for !<integer> syntax to inject arbitrary words into the binary. This feature is used for testing.
• Internal cleanups and additional tests.

2015-09-25

• Updated to Rev32 headers
  • Core instructions and enumerants from Rev 32 are supported by the assembler.
  • Capability dependencies may be incomplete or incorrect.
• Assembler ID syntax:
  • All IDs must use the % prefix before the name.
  • ID name syntax is checked: it must be made from letters, numbers or underscore (_).
  • IDs with different names always map to different ID numbers. Previously, a numeric ID such as %2 could accidentally map to the same numeric ID as named ID %foo.
  • In particular, an ID with a number for a name doesn't necessarily map to that number. E.g. %2 doesn't necessarily map to ID 2.
• Disassembler emits mask expressions for mask combinations instead of erroring out.
• Fixed parsing and printing of Execution Scope and Memory Semantics operands. They are supplied as IDs, not as literals.

2015-09-18

• MILESTONE: This version of the assembler supports all of SPIR-V Rev31, provided you only use 32-bit values.
• Fixes build problems with MSVC 2013.
• Assembler supports mask expressions
  • e.g. OpStore %ptr %value Volatile|Aligned 4
  • See syntax.md for more.
• Assembler supports image operands from Rev31.
  • This uses mask expression support.
• Assembler supports enum operands: storage class enums, sampler addressing mode, sampler filter mode, dim, image format
• More support for !<number> syntax. Still incomplete.
• Disassembler will print 64-bit values correctly.

2015-09-15

• Fixed spelling of Function Control "Inline" enumerated value.
• Fixed: Aligned memory access flag takes a literal number operand.
• Fixed parsing of scope ID arguments, e.g. for group operations.

2015-09-11

• Assembly format must be consistent across the entire source module.
  • Add API assembler and disassembler entry points to control the format.
  • Add command line options to assembler and disassembler to force it: --syntax-format=assignment --syntax-format=canonical The default is "assignment".
• Fixes decorations:
  • Names: SaturatedConversion, FuncParamAttr NoCapture
  • Values: Fixes values for some decorations: BuiltIn LocalInvocationId, and BuiltIn SubgroupId
  • All handling of FPFastMathMode masks.
  • LinkageAttributes now requires the literal string operand.
• Fixes capabilities: Adds ImageMipmap, and capabilities from LiteralSampler through SampleRateShading.

2015-09-09

• Avoid confusion about ownership of storage:
  • spv_binary is only used for output of the assembler, and should always be destroyed with spvBinaryDestroy.
  • spv_text is only used for output of the disassembler, and should always be destroyed with spvTextDestroy.
  • Inputs to the assembler and disassembler are provided as pointer and length arguments.
• Fixed parsing of floating point literals.
• Fixed the -p option for the disassembler executable.
• Fixed a build break on MSVC when using a ternary operator with conflicting types.
• More test coverage and other cleanups.

2015-09-04

• The parser has been overhauled
  • We use an automatically generated table to describe the syntax of each core instruction. The changes to the SPIR-V spec document generator to create this table are still being developed.
  • The parser uses a dynamically updated list of expected operand types. It is expanded as needed for variable-length lists of operands, and consumed during the parse. See the uses of spv_operand_pattern_t.
  • The syntax of enum operands and their potential operands is still hand-coded. (That might change depending on the cost-benefit tradeoff.)
• We are actively increasing test coverage.
• We have tweaked the CMake build rules to make it easier to integrate into other packages. Google is integrating SPIR-V Tools into the Vulkan conformance test suite.
• New code tends to use Google C++ style, including formatting as generated by clang-format --style=google.
• The spvBinaryToText and spvTextToBinary interfaces have been updated to remove a conceptual ambiguity that arises when cleaning up spv_binary_t and spv_text_t objects.

Where is the code?

The master branch of the repository is maintained by Kenneth Benzie k.benzie@codeplay.com.

Please submit any merge requests as stated in these instructions.

Build

The project uses CMake to generate platform-specific build configurations. To generate these build files issue the following commands.

mkdir <spirv-dir>/build
cd <spirv-dir>/build
cmake [-G<platform-generator>] ..

Once the build files have been generated, build using your preferred development environment.

CMake Options

• SPIRV_USE_SANITIZER=<sanitizer> - on UNIX platforms with an appropriate version of clang this option enables the use of the sanitizers documented here, this should only be used with a debug build, disabled by default
• SPIRV_COLOR_TERMINAL=ON - enables color console output, enabled by default
• SPIRV_WARN_EVERYTHING=OFF - on UNIX platforms enable the -Weverything compiler front end option, disabled by default
• SPIRV_WERROR=OFF - on UNIX platforms enable the -Werror compiler front end option, disabled by default

Library

Usage

In order to use the library from an application, the include path should point to <spirv-dir>/include, which will enable the application to include the header <spirv-dir>/include/libspirv/libspirv.h then linking against the static library in <spirv-build-dir>/bin/libSPIRV.a or <spirv-build-dir>/bin/SPIRV.lib. The intention is for this to be a C API, however currently it relies on the generated header spirv.h meaning this is currently a C++ API.

• SPIRV - the static library CMake target outputs <spirv-dir>/lib/libSPIRV.a on Linux/Mac or <spirv-dir>/lib/SPIRV.lib on Windows.

Entry Points

There are three main entry points into the library.

• spvTextToBinary implements the assembler functionality.
• spvBinaryToText implements the disassembler functionality.
• spvValidate implements the validator functionality.

Source

In addition to the interface header <spirv-dir>/include/libspirv/libspirv.h the implementation source files reside in <spirv-dir>/source/*.

The parsers for the assembler and disassembler use a table describing the syntax of each core instruction. This table can be generated from the SPIR-V document generator:

1. Apply the patch in source/core_syntax_table.patch to the document generator.
2. Run the document generator with the -a option and place the results in the opcode.inc file in the SPIR-V Tools source directory.
3. Be aware of version skew: The SPIR-V document generator might target a newer verison of the spec than targeted by the SPIR-V tools.

Assembler

The standalone assembler is the binary called spirv-as and is located in <spirv-build-dir>/bin/spirv-as. The functionality of the assembler is implemented by the spvTextToBinary library function.

The assembler operates on the textual form.

• spirv-as - the standalone assembler
  • <spirv-dir>/bin/spirv-as

Options

• -o <filename> is used to specify the output file, otherwise this is set to out.spv.

Syntax

See syntax.md for the assembly language syntax.

Disassembler

The standalone disassembler is the binary called spirv-dis and is located in <spirv-build-dir>/bin/spirv-dis. The functionality of the disassembler is implemented by the spvBinaryToText library function.

The disassembler operates on the binary form.

• spirv-dis - the standalone disassembler
  • <spirv-dir>/bin/spirv-dis

Options

• -o <filename> is used to specify the output file, otherwise this is set to out.spvasm.
• -p prints the assembly to the console on stdout, this includes colored output on Linux, Windows, and Mac.

Validator

The standalone validator is the binary called spirv-val and is located in <spirv-build-dir>/bin/spirv-val. The functionality of the validator is implemented by the spvValidate library function.

The validator operates on the binary form.

• spirv-val - the standalone validator
  • <spirv-dir>/bin/spirv-val

Options

• -basic performs basic stream validation, currently not implemented.
• -layout performs logical layout validation as described in section 2.16 Validation Rules, currently not implemented.
• -id performs ID validation according to the instruction rules in sections 3.28.1 through 3.28.22, enabled but is a work in progress.
• -capability performs capability validation and or reporting, currently not implemented.

Tests

The project contains a number of tests, implemented in the UnitSPIRV executable, used to drive the development and correctness of the tools, these use the googletest framework. The googletest source is not provided with this project, to enable the tests place the googletest source in the <spirv-dir>/external/googletest directory, rerun CMake if you have already done so previously, CMake will detect the existence of <spirv-dir>/external/googletest then build as normal.

Future Work

Assembler and disassembler

• WIP: Fix disassembler support for non-32-bit numeric literals
• WIP: Fix bug: Assembler can't use extended instructions from two different extended instruction imports.
• Support 16-bit floating point literals.

Validator

• Adopt the parser strategy used by the text and binary parsers.
• Complete implementation of ID validation rules in spirv-val.
• Implement section 2.16 Validation Rules in spirv-val.
• Implement Capability validation and or report in spirv-val.
• Improve assembly output from spirv-dis.
• Improve diagnostic reports.

Known Issues

• Header file libspirv.h cannot be used in C code.
• Improve literal parsing in the assembler, currently only decimal integers and floating-point numbers are supported as literal operands and the parser is not contextually aware of the desired width of the operand.
• Sometimes the assembler will succeed, but the disassembler will fail to disassemble the result. (Is this still true?)

Licence

Copyright (c) 2015 The Khronos Group Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and/or associated documentation files (the "Materials"), to deal in the Materials without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Materials, and to permit persons to whom the Materials are furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Materials.

MODIFICATIONS TO THIS FILE MAY MEAN IT NO LONGER ACCURATELY REFLECTS KHRONOS STANDARDS. THE UNMODIFIED, NORMATIVE VERSIONS OF KHRONOS SPECIFICATIONS AND HEADER INFORMATION ARE LOCATED AT https://www.khronos.org/registry/

THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.