SPIRV-Tools/readme.md

# 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)

2015-11-02
* Progress toward making `libspirv.h` a C API:
   * Use C header `spirv.h` instead of C++ header `spirv.hpp`
* Fixed UTF-8 tests on Windows
* Fixed "Generator" enums (SPIR-V module word 2)
* Fixed CMake location of Google Mock
* Other internal cleanups

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](syntax.md#immediate)
  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`](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](https://cvs.khronos.org/wiki/index.php/How_to_access_and_use_the_Khronos_Gitlab_Repository).


## 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](http://clang.llvm.org/docs/UsersManual.html#controlling-code-generation),
  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`](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](https://github.com/google/googletest) framework. The
[googletest](https://github.com/google/googletest) source is not provided with
this project, to enable the tests place the
[googletest](https://github.com/google/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.

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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,
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