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2020-02-28Constant time dynamic cast (#1250)jsmall-nvidia
* Constant time dynamic cast. * Use getClassInfo virtual function. Fix problem because of instanciation of specializations was in wrong order for clang. * Improve comments. * Improve comment. * Ensure s_first is defined before kClassInfo, to ensure construction ordering.
2020-02-19Fix a reference-counting bug in one of the session creation routines. (#1230)Tim Foley
This is pretty straightforward, because we were calling `Session::init` (which can retain/release the session) on a `Session*` (no reference held). The catch is that our current tests use the older form of the Slang API, while Falcor relies on the newer API, and so the recent change to our reference-counting logic introduced a regression that we didn't detect in testing. This change just fixes the direct issue but doesn't address the gap in testing. A better long-term fix would be to fully define our "1.0" API, shift our testing to it, and layer the old API on top of it (to try and avoid regressions for client code).
2020-02-06Literal handling improvements (#1202)jsmall-nvidia
* WIP: 64 literal diagnostic and truncation. * Improve how integer truncation is handled/supported. Added literal-int64.slang test. Set a suffix on all literals. Fixed problem on C++ based targets where l suffix was not the same as int() cast. So on C++ derived emitters, int() is used instead of l suffix to have same behavior across targets. * Add literal diagnostic testing. * Allow lexer to lex - in front of literals. * Fix lexing and converting int literal with -. * Too large small values of floats become inf. Handling writing inf types out on different targets. Add function to deterimine if a float literals kind. * Roll back the support of lexer lexing negative literals. * Fixed tests broken because of diagnostics numbers. Improved _isFinite * Fix compilation on linux. * Fix problem with abs on linux - use Math::Abs. * Fix typo. * * Improve warnings for float literals zeroed * Improved 64 bit type documentation * Handle half * Improved comments * Fixed tests broken * Use capital letters for suffixes. * Make default behavior on outputting a int literal that is an 'int32_t' is cast (not suffix) to avoid platform inconsistencies. Improve documentation for 64 bit types. Make tests cover material in docs. * Fixed tests. * Rename FloatKind::Normal -> Finite * Fix half zero check.
2020-01-31Some Slang API additions (#1195)Tim Foley
* Some Slang API additions These are additions to the public Slang API that came up while I was trying to write an example to demonstrate GPU printing. The additions aren't strictly necessary for the example, but I found these to be missing services when writing the code the way I wanted to. The main public changes are: * There is a new distinct `IEntryPoint` interface which inherit from `IComponentType` (much like `IModule` before). For now this doesn't expose any new functions on top of `IComponentType`, but I expect it to do so eventually. * It is now possible to get the `IModule` for a specific translation unit in a compile request with `spCompileRequest_getModule`. Even for a compile request that had only one translation unit this is *not* the same object as gets returned by `spCompileRequest_getProgram`. The latter should probably be called `*_getLinkedProgram` because it returns a composite component type that links the module with everything it `import`s. * An `IModule` can look up entry points declared in the module. Eventually a module should support looking up most of the declarations in the module (e.g., types) by name, but entry points are an obvious case. * A new `link()` operation is added to `IComponentType`. It is possible to have component types that have unsatisfied dependencies, such that trying to generate kernel code from them will fail. The `link()` operation tries to produce a new composite component type that combines a component with its dependencies, to enable code generation. The implementation of end-to-end compilation was using a function like this internally, but it hadn't been exposed to the API. Notes on the implementation: * The list of entry points declared in a given translation unit has moved from `TranslationUnitRequest` to the `Module` inside of it. * `EntryPoint` now has to do a song and dance much like `Module` to both inherit from `ComponentType` and support the `IEntryPoint` interface. * The `Session* m_session` member in `Linkage` (in terms of public API, this is the `slang::ISession` holding a pointer to the `slang::IGlobalSession`) has been changed to a `RefPtr`. Without this change an application can't just hold onto a `ComPtr<slang::ISession>`; they also need to retain the `IGlobalSession` or things will crash. The new behavior seems more correct, but I worry that it might introduce a leak. * The `asInternal` operation for `IComponentType` had to be updated to not just perform a cast. A type like `Module` has two `IComponentType` sub-objects, and only one of these is at the same address as the `ComponentType` base. * Similarly, the `Module::getInterface` logic was changed to fall back to `Super::getInterface` for all the cases other than `IID_IModule`, so that it would be guaranteed to return the `IComponentType` at the same address as `ComponentType` in response to a `queryInterface`. * Fixes for memory retain cycles As part of the earlier change, I made the `Linkage` type hold a `RefPtr` to the `Session`. The motivation there is it lets a user hang onto just a `slang::ISession` without having to also retain the `slang::IGlobalSession` for no immediately apparent reason. There are two problems that this surfaced, one pre-existing and one new. The new problem was that `Session` already held a `RefPtr<Linkage> m_builtinLinkage` for the linkage that holds the stdlib code. I solved that problem by splitting the parent pointer in `Linkage` into two pointers: a raw pointer that is used to actually locate the parent session, and a ref-counted one that can be used to *optionally* retain the parent session. The builtin linkage is then set up to explicitly not retain its parent, thus breaking the cycle. The second problem was a pre-existing one, where every `ComponentType` was holding a retained pointer to its parent `Linkage`, but in turn the `Linkage` was holding retained pointers to many `ComponentTypes` (and subclasses thereof). For this case I used the more expedient fix of making the parent pointer into a raw pointer, and figuring that it is a reasonable rule to expect user to retain the `Linkage` (aka `slang::ISession`) that owns a component type if they want to be able to use the component type. I might need/want to investigate a better fix for the latter issue, but for now this seems to clean up the issues I was seeing in the tests. Fingers crossed.
2019-12-12Feature/source downstream compiler (#1153)jsmall-nvidia
* CPPCompiler -> DownstreamCompiler * Added DownstreamCompileResult to start abstraction such that we don't need files. * * Split out slang-blob.cpp * Made CompileResult hold a DownstreamCompileResult - for access to binary or ISlangSharedLibrary * Keep temporary files in scope. * Add a hash to the hex dump stream. * Move all file tracking into DownstreamCompiler. * WIP support for nvrtc. * WIP: Adding support for nvrtc compiler. Adding enum types, wiring up the nvrtc into slang. * Fix remaining CPPCompiler references. * Fix order issue on target string matching. * Use ISlangSharedLibrary for nvrtc. * Use DownstreamCompiler for nvrtc. * WIP first pass at compilation win nvrtc. * Added testing if file is on file system into CommandLineDownstreamCompiler. Added sourceContentsPath. * Make test cuda-compile.cu work by just compiling not comparing output. * Genearlize DownstreamCompiler usage. * Fix warning on clang. * Remove CompilerType from DownstreamCompiler. * Use DownstreamCompiler interface for all compilers. NOTE for FXC, DXC and GLSLANG this doesn't mean using 'compile' - it's still extracting functions from shared library. * Replace DownstreamCompiler::SourceType -> SlangSourceLanguage * Replace _canCompile with something data driven. * Fix compiling on gcc/clang for DownstreamCompiler. * Moved some text conversions into DownstreamCompiler. * Fix problem on non-vc builds with not having return on locateCompilers for VS. * Change so no warning for code not reachable on locateCompilers for vs.
2019-12-12Use DownstreamCompiler for all downstream compilers (#1152)jsmall-nvidia
* CPPCompiler -> DownstreamCompiler * Added DownstreamCompileResult to start abstraction such that we don't need files. * * Split out slang-blob.cpp * Made CompileResult hold a DownstreamCompileResult - for access to binary or ISlangSharedLibrary * Keep temporary files in scope. * Add a hash to the hex dump stream. * Move all file tracking into DownstreamCompiler. * WIP support for nvrtc. * WIP: Adding support for nvrtc compiler. Adding enum types, wiring up the nvrtc into slang. * Fix remaining CPPCompiler references. * Fix order issue on target string matching. * Use ISlangSharedLibrary for nvrtc. * Use DownstreamCompiler for nvrtc. * WIP first pass at compilation win nvrtc. * Added testing if file is on file system into CommandLineDownstreamCompiler. Added sourceContentsPath. * Make test cuda-compile.cu work by just compiling not comparing output. * Genearlize DownstreamCompiler usage. * Fix warning on clang. * Remove CompilerType from DownstreamCompiler. * Use DownstreamCompiler interface for all compilers. NOTE for FXC, DXC and GLSLANG this doesn't mean using 'compile' - it's still extracting functions from shared library. * Fix compiling on gcc/clang for DownstreamCompiler. * Fix problem on non-vc builds with not having return on locateCompilers for VS. * Change so no warning for code not reachable on locateCompilers for vs.
2019-12-12Slang compiles CUDA source via NVRTC (#1151)jsmall-nvidia
* CPPCompiler -> DownstreamCompiler * Added DownstreamCompileResult to start abstraction such that we don't need files. * * Split out slang-blob.cpp * Made CompileResult hold a DownstreamCompileResult - for access to binary or ISlangSharedLibrary * Keep temporary files in scope. * Add a hash to the hex dump stream. * Move all file tracking into DownstreamCompiler. * WIP support for nvrtc. * WIP: Adding support for nvrtc compiler. Adding enum types, wiring up the nvrtc into slang. * Fix remaining CPPCompiler references. * Fix order issue on target string matching. * Use ISlangSharedLibrary for nvrtc. * Use DownstreamCompiler for nvrtc. * WIP first pass at compilation win nvrtc. * Added testing if file is on file system into CommandLineDownstreamCompiler. Added sourceContentsPath. * Make test cuda-compile.cu work by just compiling not comparing output. * Fix warning on clang.
2019-12-10DownstreamCompiler abstraction (#1149)jsmall-nvidia
* CPPCompiler -> DownstreamCompiler * Added DownstreamCompileResult to start abstraction such that we don't need files. * * Split out slang-blob.cpp * Made CompileResult hold a DownstreamCompileResult - for access to binary or ISlangSharedLibrary * Keep temporary files in scope. * Add a hash to the hex dump stream. * Move all file tracking into DownstreamCompiler.
2019-12-06Remove legacy feature for merging global shader parameters (#1139)Tim Foley
* Remove legacy feature for merging global shader parameters There is a fair amount of special-case code in the Slang compiler today to deal with the scenario where a programmer declares the "same" shader parameter across two different translation units: ```hlsl // a.hlsl Texture2D a; cbuffer C { float4 c; } ``` ```hlsl // b.hlsl cbuffer C { float4 c; } Texture2D b; ``` An important note here is that the declaration of `C` may be in a header file that both `a.hlsl` and `b.hlsl` `#include`, because from the standpoint of the parser and later stages of the compiler, there is no difference between `C` being in an included file vs. it being copy-pasted across both `a.hlsl` and `b.hlsl`. When a user invokes `slangc a.hlsl b.hlsl` (or the equivalent via the API), then they may decide that it is "obvious" that the shader parameter `C` is the "same" in both `a.hlsl` and `b.hlsl`. Knowing that the parameter is the "same" may lead them to make certain assumptions: * They may assume that generated code for entry points in `a.hlsl` and `b.hlsl` will both agree on the exact `register`/`binding` occupied by `C`. * They may assume that reflection information for their program will only reflect `C` once, and it will reflect it in a way that is applicable to entry points in both `a.hlsl` and `b.hlsl` * They may assume that the compiler can and should handle this use case even when `C` contains fields with `struct` types that are declared in both `a.hlsl` and `b.hlsl` that have the "same" definition. * They may assume that in cases where `C` is declared inconsistently between `a.hlsl` and `b.hlsl` the compiler can and will diagnose an error. Making these assumptions work in practice required a lot of special-case code: * When composing/linking programs was `ComponentType`s we had to include a special case `LegacyProgram` type that could provide these "do what I mean" semantics, since they are *not* what one would want in the general case for a `CompositeComponentType`. * During enumeration of global shader parameter in a `LegacyProgram`, we had to detect parameters from distinct modules (translation units) with the same name, and then enforce that they must have the "same" type (via an ad hoc recursive structural type match). No other semantic checking logic needs or uses that kind of structural check. * During parameter binding generation, we need to handle the case where a single global shader parameter might have multiple declarations, and make sure to collect explicit bindings from all of them (checking for inconsistency) and also to apply generated bindings to all of them. * The `mapVarToLayout` member in `StructTypeLayout` is a concession to the fact that we might have multiple `VarDecl`s for each field of the struct that represents the global scope, we might need to look up a field and its layout using any of those declarations (much of the need for this field had gone away now that IR passes are largely using IR-based layout). All of these different special cases added more complex code in many places in the compiler, all to support a scenario that isn't especially common. Most users won't be affected by the original issue, because they will do one of several things that rule it out: * Anybody using `slangc` like a stand-in for `fxc` or `dxc` and compiling one translation unit at a time will not suffer from any problems. If/when such users want consistent bindings across translation units, they already use either explicit binding or rely on consistent ordering and implicit binding. * Anybody who puts all the entry points that get combined into a pass/pipeline in a single file will not have problems. They will automatically get consistent bindings because of Slang's guarantees, and there can't be duplicated declarations when there is only one translation unit. * Anybody using `import` to factor out common declarations while compiling multiple translation units at once will not be affected. Parameters declared in an `import`ed module are the "same" in a much deeper way that it is trivial for Slang to support. Only users of the Falcor framework are likely to be affected by this, and they have two easy migration paths: either put related entry points into the same file, or factor common parameters into an `import`ed module. (It is also worth noting that for command-line `slangc`, it is possible to have a single module with multiple `.slang` files in it, which can all see global declarations like parameters across all the files. Anybody who buys into doing things the Slang Way should have no problem avoiding duplicated declarations) With the rationale out of the way, the actual change mostly just amounts to deleting lots of code that is no longer needed. An astute reviewer might notice several `assert`-fail conditions where complex Slang features were never actually made to work correctly with this legacy behavior. A small number of test cases broke with the code changes, but these were tests that specifically exercised the behavior being removed. In the case of the tests around binding/reflection generating, I rewrote the tests to use one of the idomatic workarounds (putting the shared parameters into an `import`ed module), but doing so required me to add support for `#include` when doing pass-through compilation with `fxc`. That logic added a bit more cruft than I had originally hoped to this commit, but having `#include` support when doing pass-through compilation is probably a net win. * fixup: 64-bit warning
2019-12-05Added -dump-intermediate-prefix option (#1146)jsmall-nvidia
* * Added ability to name the prefix for intermediates * Allowed paramters after -load-repro - as pretty useful if somewhat risky thing to do (depending on parameters) * Fix issue around setting arbitrary state outside of load-repro.
2019-12-04Setting downstream compiler (#1144)jsmall-nvidia
* WIP setting downstream compiler. * Setting default downstream compiler for a source type.
2019-11-19Initial work for "global generic value parameters" (#1127)Tim Foley
* Initial work for "global generic value parameters" The main new feature here is support for the `__generic_value_param` keyword, which introduces a *global generic value parameter*. For example: __generic_value_param kOffset : uint = 0; This declaration introduces a global generic value parameter `kOffset` of type `uint` that has a nominal default value of zero. The broad strokes of how this feature was added are as follows: * A new `GlobalGenericValueParamDecl` AST node type is introduces in `slang-decl-defs.h` * A new `parseGlobalGenericValueParamDecl` subroutine is added to `slang-parser.cpp`, and is added to the list of declaration cases as the callback for the `__generic_value_param` name. * Cases for `GlobalGenericValueParamDecl` are added to the declaration checking passes in `slang-check-decl.cpp`, mirroring what is done for other variable declaration cases. * A case for `GlobalGenericValueParamDecl` is aded to the `Module::_collectShaderParams` function, so that it is recognized as a kind of specialization parameter. This introduces a specialization parameter of flavor `SpecializationParam::Flavor::GenericValue` (which was already defined before this change, although it was unused). * A case for `SpecializationParam::Flavor::GenericValue` is added in `Module::_validateSpecializationArgsImpl` to check that a specialization argument represents a compile-time-constant value (not a type). * A case for `GlobalGenericValueParmDecl` is introduced in `slang-lower-to-ir.cpp` that introduces a global generic parameter in the IR * The `IRBuilder` is extended to support creating `IRGlobalGenericParam`s for the distinct cases of type, witness-table, and value parameters. The same IR instruction type/opcode is used for all cases, and only the type of the IR instruction differs. * The existing mechanisms for lowering specialization arguments to the IR, and doing specialization on the IR itself Just Work with global generic value parameters since they already support value parameters on explicit generic declarations. That's the santized version of things, but there were also a bunch of cleanups and tweaks required along the way: * The `SpecializationParam` type was extended to also track a `SourceLoc` to help in diagnostic messages, which meant some churn in the code that collects specialization parameters. * The `_extractSpecializationArgs` function is tweaked to support any kind of "term" as a specialization argument (either a type or a value). * To allow *parsing* specialization arguments that can't possibly be types (e.g., integer literals) we replace the existing `parseTypeString` routine with `parseTermString` and then in `parseTermFromSourceFile` call through to a general case of expression parsing (which can also parse types) rather than only parsing types directly. * Right before doing back-end code generation, we check if the program we are going to emit has remaining (unspecialized) parameters, in which case we emit a diagnostic message for the parameters that haven't been specialized rather than go on to emit code that will fail to compile downstream. * Within the `render-test` tool we collapse down the arrays that held both "generic" and "existential" specialization arguments, so that we just have *global* and *entry-point* specialization argument lists. This mirrors how Slang has worked internally for a while, but the difference hasn't been important to the test tool because no tests currently mix generic and existential specialization. The logic for parsing `TEST_INPUT` lines has been streamlined down to just the global and entry-point cases, but the pre-existing keywords are still allowed so that I don't have to tweak any test cases. There are several significant caveats for this feature, which mean that it isn't really ready for users to hammer on just yet: * There is no support for `Val`s of anything but integers, so there is no way to meaningfully have a generic value param with a type other than `int` or `uint`. * We allow for a default-value expression on global generic parameters, but do not actually make use of that value for anything (e.g., to allow a programmer to omit specialization arguments), nor check that it meets the constraints of being compile-time constant. * Global generic value parameters are *not* currently being treated the same as explicit generic parameters in terms of how they can be used for things like array sizes or other things that require constants. This will probably be relaxed at some point, but allowing a global generic to be used to size an array creates questions around layout. * The IR optimization passes in Slang currently won't eliminate entire blocks of code based on constant values, so using a global generic value parameter to enable/disable features will *not* currently lead to us outputting drastically different HLSL or GLSL. That said, we expect most downstream compilers to be able to handle an `if(0)` well. * Fix regression for tagged union types The change that made specialization arguments be parsed as "terms" first, and then coerced to types meant that any special-case logic that is specific to the parsing of types would be bypassed and thus not apply. Most of that special-case logic isn't wanted for specialization arguments, since it pertains to cases were we want to, e.g, declare a `struct` type while also declaring a variable of that type. The one special case that *is* useful is the `__TaggedUnion(...)` syntax, which is the only way to introduce a tagged union type right now. In order to get that case working again, all I had to do was register the existing logic for parsing `__TaggedUnion` as an expression keyword with the right callback, and the existing logic in expression parsing kicks in (that logic was already handling expression keywords like `this` and `true`). I left in the existing logic for handling `__TaggedUnion` directly where types get parsed, rather than try to unify things. A better long-term fix is to make the base case for type parsing route into `parseAtomicExpr` so that the two paths share the core logic. That change should probably come as its own refactoring/cleanup, because it creates the potential for some subtle breakage. * fixup: typo
2019-11-06Add basic support for entry points in `.slang-lib` files. (#1112)Tim Foley
* Add basic support for entry points in `.slang-lib` files. The basic idea here is that when writing out a `.slang-lib` file based on a compile request, we include new sections in the generated RIFF that represent the entry points that were requested. The entry-point information is serialized in an entirely ad hoc fashion (a future change might clean it up to use the `OffsetContainer` machinery), and contains the name, profile, and mangled symbol name of an entry point. When deserializing this information, we create a list of "extra" entry points that gets attached to the front-end compile requests. These "extra" entry points get turned into `EntryPoint` objects at the same place in the code that entry points specified on the command line or via API would be checked, but the extra entry points bypass the semantic checking and just create "dummy" `EntryPoint` objects. Aside: the ability for a compile request to end up with entry points that weren't originally specified via API or command-line is not new. We already had support for compiling a translation unit with entry points entirely specified via `[shader(...)]` attributes, and this new support tries to function similarly. Because the "dummy" entry points don't retain AST-level information, several parts of the code have been modified to defensively check for `EntryPoint` objects without a matching AST declaration, and skip over them. The main place where this creates a problem is paramete binding, where ignoring the dummy entry point is appropriate since we currently assume linked-in library code has been laid out manually. One small cleanup here is that the `-r` command-line flag and the `spAddLibraryReference` API functio now bottleneck through a common routine to do their work, so that they both gain the new behavior without needing copy-paste programming. In order to keep the existing test case for library linking with entry points working, I had to add a flag to the `render-test` tool so that it can skip specifying entry point names as part of the compile request it creates. In that case it must instead assume that the entry points will be added to the compile request via other means. This logic is a bit magical, and hints that we should be looking for other ways to expose the library linking functionality over time. * fixup: remove alignment assertion
2019-11-05API support for IR modules - setting references to libs, and returns lib ↵jsmall-nvidia
from compilation (#1105) * Added RiffReadHelper * Move type to fourCC in Chunk simplifies some code. * Make MemoryArena able to track external blocks. Allow ownership of Data to vary. Changed IR serialization to use moved allocations to avoid copies. As it turns out all of the array writes could use unowned data, but doing so requires the IRData to stay in scope longer than IRSerialData, which it does at the moment - but perhaps needs better naming or a control for the feature. * Write out slang-module container. * WIP on -r option. Loading modules - with -r. * Making the serialized-module run (without using imported module). * Split compiling module from the test. * Separate module compilation with a function working. * Remove serialization test as not used. * Fix warning on gcc. * Updated test to have types across module boundary. * Allow entry point declaration. A test that tries to build with just an entry point declaration and a module. * Try to make link work with multiple modules. * Multi module linking first pass working. * Multi module test working with -module-name option * Added feature to repro manifest of approximation of command line that was used. * Use isDefinition - for determining to add decorations to entry point lowering. * Added support for repo-file-system.h More precise control of CacheFileSystem. Allow RelativeFileSystem to strip paths optionally. Use canonical paths in PathInfo cache. Fix bug in -D options for command line output of StateSerailizeUtil * Add missing slang-options.h * Fix bug in bit slang-state-serialize.cpp with bit removal. * Added documentation around -repro-file-system Added spLoadReproAsFileSystem function. * Fix warning. * spAddLibraryReference * * Add support for slang-lib extension * Container output when using -no-codegen option * Use the m_containerFormat to determine if the module container is constructed. Store the result in a blob. This allows for potential access via the API. Write the blob if a filename is set. Use m_ prefix for container variables. * Added spGetContainerCode. Made spGetCompileRequestCode work.
2019-11-01Using repro as a file system (#1104)jsmall-nvidia
* Added RiffReadHelper * Move type to fourCC in Chunk simplifies some code. * Make MemoryArena able to track external blocks. Allow ownership of Data to vary. Changed IR serialization to use moved allocations to avoid copies. As it turns out all of the array writes could use unowned data, but doing so requires the IRData to stay in scope longer than IRSerialData, which it does at the moment - but perhaps needs better naming or a control for the feature. * Write out slang-module container. * WIP on -r option. Loading modules - with -r. * Making the serialized-module run (without using imported module). * Split compiling module from the test. * Separate module compilation with a function working. * Remove serialization test as not used. * Fix warning on gcc. * Updated test to have types across module boundary. * Allow entry point declaration. A test that tries to build with just an entry point declaration and a module. * Try to make link work with multiple modules. * Multi module linking first pass working. * Multi module test working with -module-name option * Added feature to repro manifest of approximation of command line that was used. * Use isDefinition - for determining to add decorations to entry point lowering. * Added support for repo-file-system.h More precise control of CacheFileSystem. Allow RelativeFileSystem to strip paths optionally. Use canonical paths in PathInfo cache. Fix bug in -D options for command line output of StateSerailizeUtil * Add missing slang-options.h * Fix bug in bit slang-state-serialize.cpp with bit removal. * Added documentation around -repro-file-system Added spLoadReproAsFileSystem function. * Fix warning.
2019-10-31Reference IR modules with entry point (#1101)jsmall-nvidia
* Added RiffReadHelper * Move type to fourCC in Chunk simplifies some code. * Make MemoryArena able to track external blocks. Allow ownership of Data to vary. Changed IR serialization to use moved allocations to avoid copies. As it turns out all of the array writes could use unowned data, but doing so requires the IRData to stay in scope longer than IRSerialData, which it does at the moment - but perhaps needs better naming or a control for the feature. * Write out slang-module container. * WIP on -r option. Loading modules - with -r. * Making the serialized-module run (without using imported module). * Split compiling module from the test. * Separate module compilation with a function working. * Remove serialization test as not used. * Fix warning on gcc. * Updated test to have types across module boundary. * Allow entry point declaration. A test that tries to build with just an entry point declaration and a module. * Try to make link work with multiple modules. * Multi module linking first pass working. * Multi module test working with -module-name option * Use isDefinition - for determining to add decorations to entry point lowering.
2019-10-25Refactor semantic checking code into more files (#1097)Tim Foley
The semantic checking logic was all inside `slang-check.cpp` and as a result this was a monster file that was extremely hard to follow. This change splits `slang-check.cpp` into several smaller files, although some of the resulting files are still quite large. This change attempts to be a copy-paste job as much as possible and does *not* perform any cleanup on naming, structure, duplication, etc. in the code it deal with. No function bodies or signatures have been touched.
2019-10-25Don't use mangled names when emitting code (#1096)Tim Foley
* Small cleanup to how standard-library code gets marked Declarations in the standard library used to be individualy marked with `FromStdLibModifier` so that downstream passes (notably IR lowering) could treat them specially. At some point we simplified things by just looking for `FromStdLibModifier` in the ancestor list of a declaration, so that we could handle nested declarations without having to recursively attach the modifier to everything. This change simplifies things a bit further in that the `FromStdLibModifier` now only get attached to the `ModuleDecl`, since that will be on the ancestor chain of all the declarations anyway. The second change here is that we attach this marker modifier *before* we parse and do semantic checking on the module, rather than after. There is no code in this change that relies on that difference, but changing the timing of when we attach the modifier means that the semantic checking logic can now reliably detect if something represents a declaration in the standard library. * Change implementation of `sign()` for GLSL target Issue #602 related to the `sign()` function having a different return type between GLSL and HLSL/SLang. At the time, the issue was fixed by adding special-case logic in the emit pass that looked for the `sign()` function by name. This change cleans up that logic to work using the existing `__target_intrinsic` mechanism instead. * Make sure code emit doesn't depend on mangled names There was existing logic in the HLSL/GLSL emit path (that got copy-pasted into the C/C++ path) where if a builtin function didn't have an application `__target_intrinsic` modifier (`IRTargetIntrinsicDecoration` at the IR level), we used some fairly fragile logic to take the mangled symbol name for a function and unmangle it to recover the original name, as well as the number of parameters (to detect member functions). This approach had always been a kludge, and we have reached a point where it actively hinders forward progress on some valuable new features. The big idea of this change is fairly simple: in the IR lowering pass we detect when we have a stdlib function that ought to have an intrinsic definition but doesn't have a "catch-all" `__target_intrinsic` modifier applied. If we discover such a function, we go ahead and emit it to the IR with just such a catch-all modifier. (The main alternative here would be to require that all functions in the stdlib be manually marked `__target_intrinsic` and make this a front-end issue where we get errors if we write stdlib functions wrong, but this workaround is more expedient for now) Some of the logic around target intrinsics already handled the idea of having catch-all intrinsic modifiers/decorations with an empty target name, but that support wasn't 100% complete so this change strives to get it working. One detail that was only being handled along this mangled-name path was support for emitting calls using member-function syntax. I updated the generic handling of `__target_intrinsic`-based calls to support specifying a member function name using a prefix `.` on the definition string. With this work in place, it is possible to clean up a bunch of logic in the `emit` code that had to assume that any function without a body/definition must be an intrinsic. Instead, with this change we can now use the presence of a suitable `IRTargetIntrinsicDecoration` as the indicator that a function is an intrinsic. This should make the emit logic a bit more robust. One wrinkle that remains with this change is the special handling of functions that get the name `operator[]` (that is, the `get`/`set`/etc. accessors for `__subscript` declarations). The logic no longer depends on the mangled name, but it still feels a bit gross to have this kind of string-based special case (especially since it is our main/only special case like this). Another wrinkle is that the C/C++ back-end logic for handling intrinsic functions largely mirrors the HLSL/GLSL case, but can't just use the same exact code because it has to be intercepted by the logic that generates some of the required functions on-demand. There's still a net cleanup with this change, but there is probably an opportunity to remove even more duplication down the road.
2019-10-24* Functionality to dump repo if there is a failure throught the ↵jsmall-nvidia
-dump-repro-on-failure option (#1095) * Small typo fix
2019-10-24OffsetContainer serialization (#1093)jsmall-nvidia
* OffsetContainer with unit tests. * State serialization working with OffsetContainer. * Fixes to make work with OffsetContainer. * Added OffsetContainer documentation. * Remove RelativeContainer. * Fix problem with + on Offset32Ptr on windows x86 target. * * Made OffsetBase a base class of OffsetContainer. * Added MemoryOffsetBase to just handle being a chunk of memory. * * Use operator[] to access contents of OffsetContainer * Fix the type hash to work across different size_t sizes. * Fixed some Offset type related comments. * Fix bug around using asBase, because it returns a reference just using 'auto' will means it becomes a value type. Remove assignment and copy ctor from OffsetBase. * Evaluation order of assignment can lead to wrong behavior with Offset32Ptr/raw pointers. Document the fact, and fix in StateSerializeUtil.
2019-10-23Expose more repro in API, support output params. (#1087)jsmall-nvidia
* Added spEnableReproCapture to the API. * Added MemoryStreamBase - which can be used to read from without copyin the data. Added the missing Repro API functions - spEnableReproCapture and spExtractRepro. Added support for serializing output filenames. * Improved naming around Stream. Brought Stream and sub types closer to code conventions. * Renamed content -> contents in Stream.
2019-10-21`Repro` functionality (#1085)jsmall-nvidia
* WIP on serialize/save state. * Relative string encoding. * Added RelativeContainer unit test. Split out RelativeContainer into core. * Fix bug in RelativeString encoding. * More work around relative container. * Fix checks. * Use RelativeBase for safe access. Use malloc/free/realloc instead of List. * Add natvis support for relative types. * Setting up of state (not includes) writing of repro state. * Capture after spCompile. * Writing SourceFile and file system files. Added -dump-repo * First pass at loading state. * First pass at reading repro. * Small optimization around Safe32Ptr * Refactor how repro data is stored - to make saving off the files more simple, by having all all backed by 'files'. Make file loading always set up PathInfo so we get uniqueIdentifier info. * Generate unique file names. * Added RelativeFileSystem Added saveFile to ISlangFileSystemExt and implemented for interfaces Added mechanism to save of files (and manifest) * Added ability to replace files in repo with directory holding their contents. * Add support for entry points. * Fix problem compiling on linux. * Added SIMPLE_EX option, where everything on command line must be specified. * Fix typo in unit test for relative container. * Fix another typo in unit test for RelativeContainer. * Fix small bugs. * Fix release unused variable issue in slang-state-serialize.cpp * Fix checking for SIMPLE_EX in testing, else broke COMMAND_LINE_SIMPLE. * Fix warnings on 32 bit debug build. * Added import-subdir-search-path-repro.slang test. Although disabled for now as writes to root of slang project. * Remove wrong version of import-subdir-search-path-repro.slang * Added import-subdir-search-path-repro.slang
2019-10-17Initial work on representing layout at IR level (#1079)Tim Foley
* Initial work on representing layout at IR level This change starts the process of making the back-end of the compiler independent of the AST-level layout information (`TypeLayout`, `VarLayout`, etc.) so that it instead only relies on layout information that is embedded into IR modules. This brings us incrementally closer to a world in which the back-end could be run without the AST-level structures even existing (e.g., for an application that just wants to ship IR without any AST information for IP protection, while still supporting some amount of linking and specialization). The main parts of the change are: * There is a bunch of incidental churn related to specifying entry points by index instead of the `EntryPoint` object for certain operations. This ends up being a better choice because we can use the index to look up side-band information about the entry point that might not be stored on the `EntryPoint` object itself. In particular... * We expand the `ComponentType` interface to support looking up the mangled name of an entry point by index. In common cases (no generic/interface specialization) this would be the same as asking the `EntryPoint` for its mangled name, but in cases where we have specialized a generic entry point, the mangled name would include speicalization arguments that are only available on the `SpecializedComponentType` that wraps the entry point. This part of the change isn't ideal and there might be a better solution waiting to be invented. Note that we store mangled entry point names as strings rather than using `DeclRef`s because that ensures that the information could be serialized and deserialized without a dependence on the AST. * The `TargetProgram` type (which represents binding a specific `ComponentType` for a shader program to a specific `TargetRequest` that represents the target platform) is expanded to include an `IRModule` that represents layout information, in addition to the AST-level `ProgramLayout` it already contained. We create both of these objects at the same time (on-demand) to simplify the overall flow (so that any code that triggers creation of the AST-level layout will also ensure that the IR-level layout exists). * A bunch of code in the emit passes that was passing down layout-related objects has been eliminated. It appears that most of those objects weren't actually being used, so this is just a cleanup, but it helps ensure that the back-end steps are "clean" and don't depend on the AST-level information. The one big exception here is that the emit logic needs to know the stage for the entry point being emitted (to deal with one wrinkle in translating DXR to VKRT). * A big change (actually introduced by @jsmall-nvidia in a branch that this change copied and then built from) is to introduce some more explicit IR instructions to represent layout information, notably an `IRTypeLayout` and an `IRVarLayout`. For now these objects still reference their AST equivalents, but the separation gives us an incremental path to move information from the AST-level objects over to the IR ones. This work includes logic in `IRBuilder` to construct the IR-level layout objects from the AST-level ones on-demand, so that the existing code paths that try to attach AST-level layout will continue to work for now. * Because layout information is now embedded in the IR, the `slang-ir-link.cpp` logic loses a lot of cases that used to deal with attaching AST-level layout objects to IR-level instructions during the linking process. Instead, the linker now assumes that one (or more) of the input IR modules will have layout information associated with it, and the linker makes sure to copy layout decorations (and the instructions they reference) from the input IR module(s) to the output using its more ordinary mechanisms. * Inside `slang-lower-to-ir.cpp`, we add logic to construct an IR module in a `TargetProgram` that simply references the global shader parameters, entry points, etc. and attaches IR layout decorations to them. This is akin to the existing pass in the same file that constructs IR to represent specialization information, and both of these passes share infrastructure with the main AST->IR lowering pass. Eventually, it is expected that this pass will encompass more of the logic for copying AST-level layout information over to IR-level equivalents. * One small wrinkle with this change was that the output for an HLSL generation test case changed some of its `#line` directives. The old code was actually more inaccurate than the new, so this change just updated the baseline. It also added some logic in the linker to make sure that when an IR instruction has multiple definitions, we try to pick up a source location from any of them, in case the "main" one somehow didn't get a location. * Another small fix was that the key/value map in `StructTypeLayout` for mapping fields/members to their layouts was keyed on `Decl*` when it really should have been `VarDeclBase*`. This change should in principle be a pure refactoring with no functionality changes, so no new tests were added. It is unfortunately also a change that has a high probability of breaking at least *some* client code, so we may want to be defensive and mark this with a new major version number (well, a new *minor* version number since we are pre-`1.0`) to give us some room for releasing hotfixes to the old version if needed. * fixup: infinite recursion bug detected by clang * fixup: remove commented-out code
2019-09-23Simple test profiling (#1062)jsmall-nvidia
* First pass support for performance profiling * Test across all elements * Fix bug - sourceContents is not used, should use rawSource. * * Add ability to get prelude from API. * Allow specifying source language for render-test * Made it possible to compile a test input file as C++ * Special handling for reflection * Added C++ impl to performance-profile.slang * Remove some clang warnings. * Output profile timings on appveyor and other TC. * Remove passing around of StdWriters (can use global). Small comment improvements.
2019-09-13Revisions to "new" Slang API based on use in Falcor (#1052)Tim Foley
* Revisions to "new" Slang API based on use in Falcor As I've been integrating the new/revised Slang API (using the "COM-lite" interfaces) I've run into some cases where the API was either missing features or didn't really work as originally implemented. This change fixes the gaps/problems that came up. There are two main things here: 1. Some of the routines that returned an `IComponentType*` as a function result weren't actually doing anythign to retain the object they returned (e.g., putting it into a cache). Leaving aside the question of whether we need to add that caching layer, it made sense to instead have the return be through an output argument. Discussion after the initial iteration of the COM-lite API came around to the point that properly reference-counting objects that get returned would be useful if we ever decide we don't like having ever-expanding memory usage for caches of specialized/composed component types. 2. There was no way with the existing API to get at an `IComponentType` that represents an entry point produced during compilation, so that a user could include it in their own composition. This change alters `spCompileRequest_getProgram` to return the global program *without* the entry points, and adds a separate `spCompileRequest_getEntryPoint`. This design lets an application compose whatever combination/layout they want, rather than being stuck with a pre-designed composition baked into the compiler. * fixup: review feedback
2019-08-28Support for getting git version from IGlobalSession (#1040)jsmall-nvidia
* Added slang-tag-version.h and travis code to generate the file. * Generate slang-tag-version.h on appveyor. * Move where slang-tag-version.h is generated on appveyor. * Dump slang-tag-version.h to console on travis. * Cat slang-tag-version.h * Added method getBuildTagVersion to IGlobalSession. Added -v option.
2019-08-20User defined downstream compiler prelude (#1028)jsmall-nvidia
* Added setDownstreamCompilerPrelude Renamed setPassThroughPath to setDownstreamCompilerPath. Fixed tests. Added prelude directory & code to TestToolUtil to setup default preludes for testing/command line apis. * Fix merge problem * Remove hacks to make prelude work by adding a search path as no longer needed with 'user prelude'. * Split up prelude into scalar intrinsics, and types. Use slang.h for main header. slang-cpp-prelude.h can now just include what it needs (relative to prelude directory) and define the few remaining things/work arounds. * Fix typo.
2019-08-15A more convoluted #pragma once file identity test, using relative paths. (#1021)jsmall-nvidia
* A more convoluted #pragma once file identity test, using relative paths. * Fix bug with passing - to slang as a command line option causes a crash. Ability to set file-system to use on command line. #pragma once tests try with 'normal' and 'read-file' only versions * OSFileSystem -> OSFileSystemExt LoadFileOSFileSystem -> OSFileSystem Implemented OSFileSystem like OSFileSystemExt as as singleton. Fixes to comments.
2019-08-12Ability to set Paths on Pass Through/Back End Compilers (#1010)jsmall-nvidia
* Expanded prelude for some other resource types. Disable C++ output for ParameterGroup. * WIP: Layout for CPU. * Fixes to CPU layout. * WIP: The uniform is output, but the variable definition is not. * WIP: Entry point parameters to global scope in C++. Handling of resource types (in so far as outputting) * Some discussion of ABI and different input types. * WIP: More C++ support around resource types. * WIP: Split up variables into different structures on emit. * WIP: Emitting C++ with wrapping up of 'Context' * WIP: C++ code has access to semantic values. Wrap in struct so can use method calls to pass shared state. Disable legalizeResourceTypes and legalizeExistentialTypeLayout * Fix structured buffer layout for CPU. * Remove testing/handling of global uniforms on CPU path. Typo fix. Changed CPU tests to use new CPU calling convention. * Check globals are working. Initalize context to zero globals. * Order the global parameters for C++ ouput by their layout. Note - that layout isn't quite working correctly because the StructuredBuffer<int> the int seems to be consuming uniform space. * Work around for reflection not having all data needed for layout ordering for C++ code. * Output constant buffers as pointers. * Entry point parameters accessed through pointer to struct. * WIP: Layout for CPU is reasonable for test case. * Only output 'f' after float literal if type marks as a float. * Cast construction works on C++. * Made IntrinsicOp::ConvertConstruct to make intent clearer. * C++ handling construction from scalar. Handle access of a scalar with .x. Check default initialization. * Comment about need for split of kIROp_construct. Release build works. * Added support from constructVectorFromScalar to C/C++ target. * Handling of in/out in C/C++. * First pass documentation CPU support. * Improvements to C++/C slang code generation documentation. * Small doc change to include need for mechansim to specify cpp compiler path. * WIP: Being able to set path for backends. * Better handling of swizzling - allow swizzling a scalar into a vector. * Fix missing/broken headers for path setting on session. * Fix for compiling using clang on Windows. * Remove Clang test code. * * Removed spSessionGetGlobalSession - no longer needed because SlangSession is slang::IGlobalSession alias. * Gave Session a ref count on spCreateSession, and have it checked on spDestroySession, so behaves correctly as ISlangUnknown Note that spDestroySession does a release (and checks the ref count on debug builds). It's behaviour could be the same as just release, but this seems closer to the original intention.
2019-08-12Callable CPU code support (#1014)jsmall-nvidia
* First pass support for compiling to a loaded shared library. * Improve documentation for cpu target. * Removed the SLANG_COMPILE_FLAG_LOAD_SHARED_LIBRARY flag. Use the SLANG_HOST_CALLABLE code target Document mechanism. * Fix typo in cpp-resource.slang In test code if the target is 'callable' we don't need to compile (indeed there is no source file). * Small refactor using CommandLineCPPCompiler as base class to implement VisualStudioCPPCompiler and GCCCPPCompiler. * Improvements around CPPCompiler. Mechanism to know products produced. Cleaning up products after execution. * Fix multiple definition of 'SourceType'
2019-08-08Make SlangSession an alias for slang::IGlobalSession (#1011)jsmall-nvidia
* Make SlangSession an alias for slang::IGlobalSession. Use asInternal/asExternal for casting in slang.cpp Special case handling of asInternal which argument dependent lookup doesn't find. * To improve implementation asInternal/asExternal in slang.cpp - tried making the internal impls forward to the Slang:: implementations. This caused ambiguities (for example when a function has using namespace Slang in it). To avoid these problems and make it clear where implementation is coming from use Slang::asInternal and removed the forwarding functions. Made the impls SLANG_FORCE_INLINE instead of inline. * Made asInternal/asExternal use SLANG_FORCE_INLINE uniformly.
2019-08-08Revise new COM-lite API (#1007)Tim Foley
* Revise new COM-lite API This change revises the "COM-lite" API that was recently introduced to try to streamline it and introduce some missing central/base concepts. The central new abstraction in the API is the notion of a "component type," which is a unit of shader code composition. A component type can have: * IR code for some number of functions/types/etc. * Zero or more global shader parameters * Zero or more "entry point" functions at which execution can start * Zero or more "specialization" parameters (types or values that must be filled in before kernel code can be generated) * Zero or more "requirements" (dependencies on other component types that must be satisfied before kernel code can be generated) Both individual compiled modules, and validated entry points are then examples of component types, and we additionally define a few services that apply to all component types: * We can take N component types and compose them to create a new component type that combines their code, shader parameters, entry points, and specialization parameters. A composed component type may also include requirements from the sub-component types, but it is also possible that by composing thing we satisfy requirements (if `A` requires `B`, and we compose `A` and `B`, then the requirement is now satisfied, and doesn't appear on the composite). * We can take a component type with N specialization parameters, and specialize it by giving N compatible specialization arguments. The result of specialization is a new component type with zero specialization parameters. Under the right circumstances the specialzed component type will be layout compatible with the unspecialized one. * One more example that isn't exposed in the public API today is that we can take a component with requirements and "complete" it by automatically composing it with component types that satisfy those requirements. This can be seen as a kind of linking step that pulls together the transitive closure of dependencies. * We can query the layout for the shader parameters and entry points of a component type, for a specific target. * We can query compiled kernel code for an entry point in a component type (for a specific target). This only works for component types with zero specialization parameters and zero requirements. The idea is that by giving users a fairly general algebra of operations on component types, they can compose final programs in ways that meet their requirements. For example, it becomes possible to incrementally "grow" a component type to represent the global root signature for ray tracing shaders as new entry points are added, in such a way that it always stays layout-compatible with kernels that have already been compiled. Much of the implementation work here is in implementing the unifying component type abstraction, and in particular re-writing code that used to assume a program consisted of a flat list of modules and entry points to work with a hierarchical representation that reflects the underlying algebra (e.g., with types to represent composite and specialized component types). There's also a hidden "legacy" case of a component type to deal with some legacy compiler behaviors that can't be directly modeled on top of the simple algebra with modules and entry points. This API is by no means feature-complete or fully developed. It is expected that we will flesh it out more when bringing up application code (e.g., Falcor) on top of the revamped API. One notable thing that went away in this change is explicit support for "entry point groups" and notions of local root signatures (especially the Falcor-specific handling of the `shared` keyword, which a previous change turned into an explicitly supported feature). With the new "building blocks" approach, it should be possible for a DXR application to deal with local root signatures as a matter of policy (on top of the API we provide). If/when we need to provide some kind of emulation of local root signatures for Vulkan (and/or if Vulkan is extended with an explicit notion of local root signatures), we might need to revisit this choice. * Fix debug build There was invalid code inside an `assert()`, so the release build didn't catch it. * fixup: warnings * fixup: more warnings-as-errors * fixup: review notes * fixup: use component type visitors in place of dynamic casting
2019-06-19Start exposing a new COM-lite API (#987)Tim Foley
* Start exposing a new COM-lite API This change is mostly about exposing a new API to the Slang compiler that allows more fine-grained control over the compilation flow. The basic concepts in the new API are: * An `IGlobalSession` is the granularity at which we load/parse the Slang stdlib, and therefore gives applications a way to amortize startup cost for the library across multiple compiles. This is a concept that might be able to go away in a future version of Slang. * An `ISession` owns all the code that gets loaded/compiled/generated. Any `import`ed modules are shared across everything in a session (we don't re-parse/-check the code when we see another `import` for the same module). Any generic- or interface-based code in the session can be specialized using types from the same session (but not necessarily across sessions). * An `IModule` is the unit of code loading and scoping. It doesn't expose any API in this change, but would be the right scope for looking up types or entry points by name. * An `IProgram` is a "linked" combination of modules and entry points from which code can be generated and reflection information queried. This change re-uses the existing reflection API types, rather than introduce a new API that duplicates that functionality. That will probably change in a future revision. There are two major pieces of functionality added here that aren't related to the new API: * We now have an API concept of "entry point groups" which are one or more entry points that are intended to be used together so that they need to have non-overlapping parameters. For now this is being used to handle "hit groups" and local root signatures for ray tracing, but I'm not sure this is a concept we will keep in the long run. * We have a very special-case (client-application-specific) flag that ascribes special meaning to the `shared` keyword, so that it can be attached to global parameters to indicate that they are actually to be part of the local root signature rather than the global one for DXR. None of the API design (including naming) here is finalized; the only reason to check in the changes at this point to avoid having a long-running branch that leads to merge pain. Clients should *not* try to depend on the new API just yet, since it is still a work in progress. * fixup: clang warning * fixup: try to detect clang C++11 support * fixup * fixup * fixup * fixup * fixup: review feedback
2019-05-31Use slang- prefix on slang compiler and core source (#973)jsmall-nvidia
* Prefixing source files in source/slang with slang- * Prefix source in source/slang with slang- prefix. * Rename core source files with slang- prefix. * Update project files. * Fix problems from automatic merge.
2019-05-20Changes required for application adoption of interface-type parameters (#963)Tim Foley
* A few changes required for application adoption of interface-type parameters There are a few small changes here that are all related in that they arose from trying to integrate support for specialization via global interface-type shader parameters into a real application. Allow querying the "pending" layout via reflection API ------------------------------------------------------ The naming here isn't ideal, and could probably use a round of "bikeshedding" to arrive at something better, but the basic idea is that when you have a type like: ``` struct MyStuff { int a; IFoo foo; int b; } ``` the fields `a` and `b` get allocated space directly in the "primary" layout for `MyStuff` (at offsets 0 and 4, with `sizeof(MyStuff) == 8`), but the `foo` field can't be allocated space until we know what concrete type will get plugged in there. If we have a concrete type in mind: ``` struct Bar : IFoo { int bar; } ``` then we can know how much space the `foo` field will take up, but we still can't allocate it space directly in `MyStuff`, because we already decided that `sizeof(MyStuff) == 8`. Now imagine we place some `MyStuff` values into constant buffers: ``` cbuffer X { MyStuff x; } cbuffer Y { MyStuff y; float4 z; } ``` In each case we know that we want to place the `MyStuff::foo` field at the end of the containing constant buffer so that it doesn't disrupt the layout of the existing fields. But that means that the offset of `MyStuff::foo` relative to the start of the `MyStuff` isn't fixed, because of unrelated fields like `z` that need to get in between. In our layout code, we handle this by having a notion of a "pending" layout. Once we know how `MyStuff::foo` will be specialized, we can compute both a "primary" and a "pending" layout for `MyStuff`, which basically treats it as if it were two distinct types: ``` struct MyStuff_Primary { int a; int b; } struct MyStuff_Pending { Bar foo; } ``` Layout for an aggregate type like the `X` or `Y` constant buffer then proceeds by computing an aggregate primary layout and an aggregate pending layout, and then finally a constant buffer or parameter block "flushes" all or part of the pending data by appending it to the primary data to get the final layout. What all this means is that a type like `MyStuff` will have two different layouts (a default one for the primary data and a "pending" one for any specialized interface-type fields), and a variable like `Y::y` will also have two variable layouts that specify offsets (one set of offsets for its primary part, and one set of offsets for its pending part). In order to handle interface-type fields with these layout rules, an application needs a way to query the "pending" part of a type or variable layout, which luckily gives it back just another type/variable layout. The API change here is minimal, although actually exploiting the new API correctly in application code could prove challenging. Allow creating of explicitly specialized types ---------------------------------------------- This feature isn't actually implemented all the way through the compiler (I just needed enough to make the API calls go through), but I've added support for specializing a type that has interface-type fields through the reflection API. This maps to an `ExistentialSpecializedType` in the AST, and I'm lowering it to the IR as a `BindExistentialsType`, although that isn't 100% correct for the future. This feature will require a future PR to actually flesh out the implementation work, but I'll wait until that is the sticking point on the application side before I do that. Introduce a tiny `Hasher` abstraction ------------------------------------- While implementing all the boilerplate for a new `Type` subclass (we really need to reduce that work...), I got fed up with how we do hash-code computation and introduced a small utility `Hasher` type that is intended to wrap up the idiom of combining hashes. For now this isn't a major change, but in the future I'd like to expand on the design a bit to clean up some of the warts around how we handle hashing: * The `Hasher` implementation can and should switch from maintaining a single `HashCode` as its state to something that contains a more complete state (larger than the hash code) and just hashes new bytes into that state as it goes. This should make it possible to implement a `Hasher` for more serious hash functions, whether MD5, CityHash, or whatever we decide is good default. * Things that are hashable shouldn't have a `getHashCode()` method, but instead should have something like a `hashInto(Hasher&)` method. This change would have the dual benefits that (1) a composite type can easily hash all the fields that contribute to its identity into the hasher with minimal fuss/boilerplate, and (2) the hashes for composite types will be of higher quality because they can exploit all the bits of the hasher's state to combine the fields, instead of restricting each sub-field to just the bits in a hash code. We should be able to incrementally improve the quality of our design there over future changes, but for now it probably isn't a critical priority. Fixes for legalization of existential types ------------------------------------------- There were some missing cases in the handling of type legalization, such that a global interface-type shader parameter that got specialized to a type that contains *only* resource-type fields would cause a crash in the legalization step. I added a test for this case, and then made `ir-legalize-types.cpp` account for this case (the code to handle it ias a bit of a kludge, and shows that the `declareVars()` routine there is getting to a level of complexity that is worrying. * fixup: review feedback
2019-04-29String/List closer to conventions, and use Index type (#959)jsmall-nvidia
* List made members m_ Tweaked types to closer match conventions. * Use asserts for checking conditions on List. Other small improvements. * List<T>.Count() -> getSize() * List<T> Add -> add First -> getFirst Last -> getLast RemoveLast -> removeLast ReleaseBuffer -> detachBuffer GetArrayView -> getArrayView * List<T>:: AddRange -> addRange Capacity -> getCapacity Insert -> insert InsertRange -> insertRange AddRange -> addRange RemoveRange -> removeRange RemoveAt -> removeAt Remove -> remove Reverse -> reverse FastRemove -> fastRemove FastRemoveAt -> fastRemoveAt Clear -> clear * List<T> FreeBuffer -> _deallocateBuffer Free -> clearAndDeallocate SwapWith -> swapWith * List<T> SetSize -> setSize Reserve -> reserve GrowToSize growToSize * UnsafeShrinkToSize -> unsafeShrinkToSize Compress -> compress FindLast -> findLastIndex FindLast -> findLastIndex Simplify Contains * List<T> Removed m_allocator (wasn't used) Swap -> swapElements Sort -> sort Contains -> contains ForEach -> forEach QuickSort -> quickSort InsertionSort -> insertionSort BinarySearch -> binarySearch Max -> calcMax Min -> calcMin * Initializer::Initialize -> initialize List<T>:: Allocate -> _allocate Init -> _init IndexOf -> indexOf * * Put #include <assert.h> in common.h, and remove unneeded inclusions * Small refactor of ArrayView - remove stride as not used * getSize -> getCount setSize -> setCount unsafeShrinkToSize->unsafeShrinkToCount growToSize -> growToCount m_size -> m_count * Some tidy up around Allocator. * Use Index type on List. * Refactor of IntSet. First tentative look at using Index. * Made Index an Int Did preliminary fixes. Made String use Index. * Partial refactor of String. * String::Buffer -> getBuffer ToWString -> toWString * Small improvements to String. String:: Buffer() -> getBuffer() Equals() -> equals * Try to use Index where appropriate. * Fix warnings on windows x86 builds.
2019-03-12Add options to control optimization and debug information (#897)Tim Foley
The short version for command-line users is: * Use `-g` to get debug info in the output, where supported * Use `-O0` to disable optimizations, in case that improves debugability * Use `-O2` for optimized/release builds where you can spend the extra compile time The command-line options are matched with new API functions `spSetDebugInfoLevel()` and `spSetOptimizationLevel()` that set the equivalent information. Right now these settings only affect how we invoke fxc and dxc. In the longer run I expect we will want to use them to control other things: * Once we are emitting our own SPIR-V, the `-g` option should control what source-level name information we include in it. * Whether or not `-g` is used could be used to decide whether we preserve the "name hints" in the IR, which in turn decide whether we output GLSL/HLSL source that uses names based on the original program. * We will eventually need/want to include some amount of optimization passes on the Slang IR, and the `-O` options should control which of those passes are enabled on a particular invocation. In this change I decided to expose the options at the level of the entire compile request for API users, and to store the actual information on the Linkage. We might want to revisit this decision and instead allow for the level of optimization to be chosen per-target as part of back-end state. Similarly, we might want to have more fine-grained control over the level of debug output per-target (although we'd still need a front-end setting to determine what debug info is generated into the Slang IR).
2019-03-10Fix `spReflection_FindTypeByName` (#891)Yong He
2019-03-08Improve support for interfaces as shader parameters (#886)Tim Foley
* Improve support for interfaces as shader parameters This change adds two main things over the existing support: 1. It is now possible to plug in concrete types that actually contain (uniform/ordinary) fields for the existential type parameters introduced by interface-type shader parameters. The `interface-shader-param2.slang` test shows that this works. 2. There is a limited amount of support for doing correct layout computation and generating output code that matches that layout, so that interface and ordinary-type fields can be interleaved to a limited extent. The `interface-shader-param3.slang` test confirms this behavior. There are several moving pieces in the change. * When it comes to terminology, we try to draw a more clear distinction between existial type parameters/arguments and existential/object value parametes/arguments. A simple way to look at it is that an `IFoo[3]` shader parameter introduces a single existential type parameter (so that a concrete type argument like `SomeThing` can be plugged in for the `IFoo`) but introduces three existential object/value parameters (to represent the concrete values for the array elements). * At the IR level, we support a few new operations. A `BindExistentialsType` can take a type that is not itself an interface/existential type but which depends on interfaces/existentials (e.g., `ConstantBuffer<IFoo>`) and plug in the concrete types to be used for its existential type slots. * Then a `wrapExistentials` instruction can take a type with all the existentials plugged in (possibly by `BindExistentialsType`) and wrap it into a value of the existential-using type (e.g., turn `ConstantBuffer<SomeThing>` into a `ConstantBuffer<IFoo>`). * The IR passes for doing generic/existential specialization have been updated to be able to desugar uses of these new operations just enough so that a `ConstantBuffer<IFoo>` can be used. * When we specialize an IR parameter of an interface type like `IFoo` based on a concrete type `SomeThing`, we turn the parameter into an `ExistentialBox<SomeThing>` to reflect the fact that we are conceptually referring to `SomeThing` indirectly (it shouldn't be factored into the layout of its surrounding type). * Parameter binding was updated so that it passes along the bound existential type arguments in a `Program` or `EntryPoint` to type layout, so that we can take them into account. The type layout code needs to do a little work to pass the appropriate range of arguments along to sub-fields when computing layout for aggregate types. * Type layout was updated to have a notion of "pending" items, which represent the concrete types of data that are logically being referenced by existential value slots. The basic idea is that these values aren't included in the layout of a type by default, but then they get "flushed" to come after all the non-existential-related data in a constant buffer, parameter block, etc. * The logic for computing a parameter group (`ConstantBuffer` or `ParameterBlock`) layout was updated to always "flush" the pending items on the element type of the group, so that the resource usage of specialized existential slots would be taken into account. * The type legalization pass has been adapted so that we can derive two different passes from it. One does resource-type legalization (which is all that the original pass did). The new pass uses the same basic machinery to legalize `ExistentialBox<T>` types by moving them out of their containing type(s), and then turning them into ordinary variables/parameters of type `T`. Big things missing from this change include: - Nothing is making sure that "pending" items at the global or entry-point level will get proper registers/bindings allocated to them. For the uniform case, all that matters in the current compiler is that we declare them in the right order in the output HLSL/GLSL, but for resources to be supported we will need to compute this layout information and start associating it with the existential/interface-type fields. - Nothing is being done to support `BindExistentials<S, ...>` where `S` is a `struct` type that might have existential-type fields (or nested fields...). Eventually we need to desugar a type like this into a fresh `struct` type that has the same field keys as `S`, but with fields replaced by suitable `BindExistentials` as needed. (The hard part of this would seem to be computing which slots go to which fields). As a practial matter, this missing feature means that interface-type members of `cbuffer` declarations won't work. The current tests carefully avoid both of these problems. They don't declare any buffer/texture fields in the concrete types, and they don't make use of `cbuffer` declarations or `ConstantBuffer`s over structure types with interface-type fields. * fixup: add override to methods * fixup: typos
2019-03-05* Fix issue with dependency including source path - even if source was ↵jsmall-nvidia
compiled from a string (#878) * Added FromString Type to PathInfo to identify paths that are not from 'files'
2019-03-02#include not using search paths (#873)jsmall-nvidia
* Fix warnings from visual studio due to coercion losing data. * Removed searchDirectories from FrontEndCompileRequest and use the one in Linkage as that is the one that is changed via Slang API. * * Add searchPaths back to FrontEndRequest * Add comments to explain the issue * Add a test to check include paths
2019-02-27Hotfix/fix stdlib error reporting (#866)jsmall-nvidia
* * Add 'identity' version of bit casts (asint, asuint, asfloat) for scalar and vector * Added identity bit casts for matrix (cos no op). We don't support matrix asint on glsl targets * Added tests in bit-cast.slang * Use kIRPseudoOp_Pos for identity asuint/asint/asfloat casts. * * Stop crash if error in stdlib * Use the buildin source manager when compiling stdlib - fixes that line numbers are displayed * Typo fix * Output line directives for 'meta' slang souce files into stdlib * Improve comments and function names.
2019-02-19First steps toward supporting interface-type parameters on shaders (#852)Tim Foley
* First steps toward supporting interface-type parameters on shaders What's New ---------- From the perspective of a user, the main thing this change adds is the ability to declare top-level shader parameters (either at global scope, or in an entry-point parameter list) with interface types. For example, the following becomes possible: ```hlsl // Define an interface to modify values interface IModifier { float4 modify(float4 val); } // Define some concrete implementations struct Doubler : IModifier { float4 modify(float4 val) { return val + val; } } struct Squarer : IModifier { ... } // Define a global shader parameter of interface type IModifier gGlobalModifier; // Define an entry point with an interface-type `uniform` parameter void myShader( unifrom IModifier entryPointModifier, float4 inColor : COLOR, out float4 outColor : SV_Target) { // Use the interface-type parameters to compute things float4 color = inColor; color = gGlobalModifier.modify(color); color = entryPointModifier.modify(color); outColor = color; } ``` The user can specialize that shader by specifying the concrete types to use for global and entry-point parameters of interface types (e.g., plugging in `Doubler` for `gGlobalModifier` and `Squarer` for `entryPointModifier`). The "plugging in" process is done in terms of a concept of both global and local "existential slots" which are a new `LayoutResourceKind` that represents the holes where concrete types need to be plugged in for existential/interface types. In simple cases like the above, each interface-type parameter will yield a single existential slot in either the global or entry-point parameter layout. Users can query the start slot and number of slots for each shader parameter, just like they would for any other resource that a parameter can consume. Before generating specialized code, the user plugs in the name of the concrete type they would like to use for each slot using `spSetTypeNameForGlobalExistentialSlot` and/or `spSetTypeNameForEntryPointExistentialSlot`. There are some major limitations to the implementation in this first change: * Parameters must be of interface type (e.g., `IFoo`) and not an array (`IFoo[3]`), or buffer (`ConstantBuffer<IFoo>`) over an interface type. Similarly, `struct` types with interface-type fields still don't work. * The work on interface-type function parameters still doesn't include support for `out` or `inout` parameters, nor for functions that return interface types (that isn't technically related to this change, but affects its usefullness). * No work is being done to correctly lay out shader parameters once the concrete types for existential slots are known, so that this change really only works when the concrete type that gets plugged in is empty. These limitations are severe enough that this feature isn't really usable as implemented in this change, and this merely represents a stepping stone toward a more complete implementation. Implementation -------------- The API side of thing largely mirrors what was already done to support passing strings for the type names to use for global/entry-point generic arguments, so there should be no major surprises there. The logic in `check.cpp` computes the list of existential slots when creating unspecialized `Program`s and `EntryPoint`s (this is logically the "front end" of the compiler), and then checks the supplied argument types against what is expected in each slot when creating specialized `Program`s and `EntryPoint`s. This again mirrors how generic arguments are handled. Type layout was extended to compute the number of existential slots that a type consumes, and will thus automatically assign ranges of slots to top-level and entry-point shader parameters in the same way it already allocates `register`s and `binding`s. The big missing feature is the ability to specialize a layout to account for the concrete types plugged into the existential-type slots. IR generation for specialized programs and entry points was slightly extended so that it attaches information about the concrete types plugged into the existential slots, and the witness tables that show how they conform to the interface for that slot. The linking step needed some small tweaks to make sure that information gets copied over to the target-specific program when we start code generation. The meat of the IR-level work is in `ir-bind-existentials.cpp`, which takes the information that was placed in the IR module by the generation/linking steps and uses it to rewrite shader parameters. For example, if there is a shader parameter `p` of type `IModifier`, and the corresponding existential slot has the type `Doubler` in it, we will rewrite the parameter to have type `Doubler`, and rewrite any uses of `p` to instead use `makeExistential(p, /*witness that Doubler conforms to IModifier*/)`. Once the replacement is done on the parameters, the existing work for specializing existential-based code when the input type(s) are known kicks in and does the rest. Testing ------- A single compute test is added to validate that this feature works. It is narrowly tailored to not require any of the features not supported by the initial implementation (e.g., all of the concrete types used have no members). The test case *does* include use of an associated type through one of these existential-type parameters, which has exposed a subtle bug in how "opening" of existential values is implemented in the front-end. Rather than fix the underlying problem, I cleaned up the code in the front-end to special case when the existential value being opened is a variable bound with `let`, to directly use a reference to that variable rather than introduce a temporary. Similarly, in the IR generation step, I added an optimization to make variables declared with `let` skip introducing an IR-level variable and just use the SSA value of their initializer directly instead. * fixup: missing files * fixup: incorrect type for unreachable return * fixup: actually comment ir-bind-existentials.cpp
2019-02-15Split front- and back-ends (#846)Tim Foley
* Split front- and back-ends This change is a major refactor of several of the types that provide the behind-the-scenes implementation of the public C API. The goal of this refactor is primarily to allow for future API services that let the user operate both the front- and back-ends of the compiler in a more complex fashion. For example, as user should be able to compile a bunch of source code into modules, look up types, functions, etc. in those modules, specialize generic types/functions to the types they've looked up, and then finally request target code to be gernerated for specialized entry points. The back-end code generation they trigger should re-use the front-end compilation work (parsing, semantic checking, IR generation) that was already performed. The most visible change is that `CompileRequest` has been split up into several smaller types that take responsibility for parts of what it did: * The `Linkage` type owns the storage for `import`ed modules, and well as the `TargetRequest`s that represent code-generation targets. The intention is that an application could use a single `Linkage` for the duration of its runtime (so long as it was okay with the memory usage), so that each `import`ed module only gets loaded once. For now, this type needs to manage the search paths, file system, and source manager, because of its responsibility for loading files. * A `FrontEndCompileRequest` owns the stuff related to parsing, semantic checking, and initial IR generation. This most notably includes the `TranslationUnitRequest`s and the `FrontEndEntryPointRequest`s (which used to be just `EntryPointRequest`s). It's main job is to produce AST and IR modules for each translation unit, and to find and validate the entry points. The front-end request does *not* interact with generic arguments for global or entry-point generic parameters. * The main output of both `import` operations and front-end translation units is the `Module` type, which is just a simple container for both the AST module (to service the reflection/layout APIs, and also for semantic checking of code that `import`s the module) and the IR module (for linking and code generation). This type captures the commonalities between the old `LoadedModule` (which is now just an alias for `Module`) and `TranslationUnitRequest` (which now owns a `Module`). * The secondary output of front-end compilation is a `Program`, which comprises a list of referenced `Module`s and validated `EntryPoint`s that will be used together. Layout and code generation both need a `Program` to tell them what modules and entry points will be used together (we don't want to just code-gen everythin that has ever been loaded into the linakge). The `Program`s created by the front-end do not include generic arguments, so they may provide incomplete layout information and/or be unsuitable for code generation. * A `BackEndCompileRequest` owns stuff related to turning a `Program` into output kernels for the targets of a `Linkage`. Most of the data it owns beyond the `Program` to be compiled is minor, so this is a good candidate for demotion from a heap-allocated object to just a `struct` of options that gets passed around. * The `CompileRequestBase` type is an attempt to wrap up the common functionality of both front-end and back-end compile requests. Most of it is just exposing the availability of a linkage and `DiagnosticSink`, so this type is a good candidate for subsequent removal. The main interesting thing it has is the flags related to dumping and validation of IR, so there is probably a good refactoring still to be made around deciding how options should be handled going forward. * Behind the scenes, the `Program` type is set up to handle some level of on-line compilation and layout work. The `Program` knows the `Linkage` it belongs to, and allows for a `TargetProgram` to be looked up based on a specific `TargetRequest`. A `TargetProgram` then allows layout information and compiled kernel code to be asked for on-demand, in order to support eventual "live" compilation scenarios. * The `EndToEndCompileRequest` type is a composition/coordination type that replaces the old `CompileRequest` in a way that uses the services of the various other types. It owns a few pieces of state that only make sense in the context of an end-to-end compile (e.g., there is really no way to "pass through" code when the front- and back-ends are run separately) or a command-line compile (everything to do with specifying output paths for files is really just for the benefit of `slangc`, and might even be moved there over time). * One important detail is that the `EndToEndCompilRequest` owns all of the string-based generic arguments for both global and entry-point generic parameters. The logic in `check.cpp` for dealing with those arguments has been heavily refactored to separate out the parsings steps that are specific to end-to-end compilation with string-based type arguments, and the semantic checking steps that result in a specialized `Program` (which can be exposed through new APIs that aren't tied to end-to-end compilation). It is perhaps not surprising that this change had a lot of consequences, so I'll briefly run over some of the main categories of changes required: * I changed the way that global generic arguments are passed via API (use `spSetGlobalGenericArgs` instead of the generic arguments for `spAddEntryPointEx`, which are not just for entry-point generics), which has been a change that we've needed for a long time. This is technically a breaking API change, although we should have very few client applications that care about it. * A bunch of places that used to take "big" objects like `CompileRequest` now just take the sub-pieces they care about (e.g., a function might have only needed a `Linkage` and a `DiagnosticSink`). This makes many subroutines or "context" struct types more generally useful, at the cost of taking more parameters. * In a few cases the conceptually clean separation of the layers breaks down (often for edge-case or compatibility features), and so we may pass along additional objects that are allowed to be null, but are used when present. A big example of this is how the back-end code generation routines accept an `EndToEndCompileRequest` that is optional, and only used to check whether "pass through" compilation is needed. We should probably look into cleaning this kind of logic up over time so that we don't need to violate the apparent separation of phases of compilation. * In cases where separation of layers was being broken for the sake of GLSL features, I went ahead and ripped them out, since all of that should be dead code anyway. * In many cases I increased the encapsulation of data in the core types to help track down use sites and make sure they are following invariants better. * In cases where code was doing, e.g., `context->shared->compileRequest->session->getThing()` I have tried to introduce convenience routines so that the usage site is just `context->getThing()` to improve encapsulation and allow changes to be made more easily going forward. * The `noteInternalErrorLoc` functionality was moved off of the compile request and into `DiagnosticSink`, since that is the one type you can rely on having around when you want to note an internal error. We may consider going forward if (and how) it should reset the counter used for noting locations on internal errors. * A few APIs now take `DiagnosticSink*` arguments where they didn't before, and as a result some public APIs need to create `DiagnosticSink`s to pass in, before going ahead and ignoring the messages. In the future there should be variations of these APIs that accept an `ISlangBlob**` parameter for the output. * fixup: missing include for compilers with accurate template checking (non-VS) * fixup: review feedback
2019-02-04Feature/view path (#824)jsmall-nvidia
* Use 'is' over 'as' where appropriate. * dynamic_cast -> dynamicCast * Replace 'dynamicCast' with 'as' where has no change in behavior/ambiguity. * Replace dynamicCast with as where doesn't change behavior/non ambiguous. * Keep a per view path to the file loaded - such that diagnostic messages always display the path to the requested file. * Add simplifyPath to ISlangFileSystemExt Simplify (if possible) paths that are set on SourceFile and SourcView - doing so makes reading paths simpler. * Fix small typo. * Improve documentation in source for getFileUniqueIdentity * Fix override warning.
2019-01-30Fixes crashes at source error.Yong He
2019-01-21Feature/file unique identity (#789)jsmall-nvidia
* * Fix memory bug around expanding va_args - needed buffer to have space for terminating 0 * Fix problem with FileWriter defaults being globals, as memory they allocate, will only be freed after return from main - work around by making StdWriters RefObject derived, and kept in scope such the writers are destroyed before checks for leaks is found * Added SimplifyPathAndHash mode for CacheFileSystem - will simplify the path and see if simplified path is in cache before reading file (limiting amout of underlying file requests) * * Added calcReplaceChar * Renamed DefaultFileSystem to OSFileSystem * Made OSFileSystem convert windows \ to / on linux * Simplified logic for caching in CacheFileSystem. * Added pragma-once-c to add extra test, but also so there is an 'include' directory in preprocessor tests. * Small fixes in pragma once test. * Simplified cache handling path, so that paths/simplified paths area always added. * Improve naming of methods for different caches. * Removed references to 'canonicalPath' and made 'uniqueIdentity' * * Re-add support for canonicalPath to ISlangFileSystem -> not for uniqueIdentifier but as a way to display 'canonicalPath' * Added peliminary support for being able to display verbose paths in a diagnostic * Added 'clearCache' support * Added verbose path support to SourceManager (now needs a ISlangFileSystemExt to do this) * Added support for '-verbose-path' option to slangc and slang-test.
2019-01-21Path simplification/hash mode, plus bug fixes (#788)jsmall-nvidia
* * Fix memory bug around expanding va_args - needed buffer to have space for terminating 0 * Fix problem with FileWriter defaults being globals, as memory they allocate, will only be freed after return from main - work around by making StdWriters RefObject derived, and kept in scope such the writers are destroyed before checks for leaks is found * Added SimplifyPathAndHash mode for CacheFileSystem - will simplify the path and see if simplified path is in cache before reading file (limiting amout of underlying file requests) * * Added calcReplaceChar * Renamed DefaultFileSystem to OSFileSystem * Made OSFileSystem convert windows \ to / on linux * Simplified logic for caching in CacheFileSystem. * Added pragma-once-c to add extra test, but also so there is an 'include' directory in preprocessor tests. * Small fixes in pragma once test. * Simplified cache handling path, so that paths/simplified paths area always added. * Improve naming of methods for different caches.
2019-01-17Feature/hash for source identity (#786)jsmall-nvidia
* * Added COMMAND_LINE_SIMPLE test type * Made how spawning works controllable by paramter/type SpawnType * Made break-outside-loop and global-uniform run command line slangc * calcRelativePath -> calcCombinedPath * Add 64 bit version of GetHash. * Add support for Hash based mode for CacheFileSystem.
2019-01-16Initial support for dynamic dispatch using "tagged union" types (#772)Tim Foley
* Initial support for dynamic dispatch using "tagged union" types Suppose a user declares some generic shader code, like the following: ```hlsl interface IFrobnicator { ... } type_param T : IFrobincator; ParameterBlock<T : IFrobnicator> gFrobnicator; ... gFrobincator.frobnicate(value); ``` and then they have some concrete implementations of the required interface: ```hlsl struct A : IFrobnicator { ... } struct B : IFrobnicator { ... } ``` The current Slang compiler allows them to generate distinct compiled kernels for the case of `T=A` and the case of `T=B`. This means that the decision of which implementation to use must be made at or before the time when a shader gets bound in the application. This change adds a new ability where the Slang compiler can generate code to handle the case where `T` might be *either* `A` or `B`, and which case it is will be determined dynamically at runtime. This means a single compiled kernel can handle both cases, and the decision about which code path to run can be made any time before the shader executes. This new option is supported by defining a *tagged union* type. Via the API, the user specifies that `T` should be specialized to `__TaggedUnion(A,B)` (the double underscore indicates that this is an experimental and unsupported feature at present). We refer to the types `A` and `B` here as the "case" types of the tagged union. Conceptually, the compiler synthesizes a type something like: ```hlsl struct TU { union { A a; B b; } payload; uint tag; } ``` The user can then allocate a constant buffer to hold their tagged union type, and when they pick a concrete type to use (say `B`), they fill in the first `sizeof(B)` bytes of their buffer with data describing a `B` instance, and then set the `tag` field to the appopriate 0-based index of the case type they chose (in this case the `B` case gets the tag value `1`). Actually implementing tagged unions takes a few main steps: * Type parsing was extended to special-case `__TaggedUnion` as a contextual keyword. This is really only intended to be used when parsing types from the API or command-line, and Bad Things are likely to happen if a user ever puts it directly in their code. Eventually construction of tagged unions should be an API feature and not part of the language syntax. * Semantic checking was extended to recognize that a tagged union like `__TaggedUnion(A,B)` shoud support an interface like `IFrobnicator` whenever all of the case types suport it, as long as the interface is "safe" for use with tagged unions (which means it doesn't use a few of the advancd langauge features like associated types). * The IR was extended with instructions to represent tagged union types and to extract their tag and the payload for the different cases as needed. * IR generation was extended to synthesize implementations of interface methods for any interface that a tagged union needs to support. Right now the implementation is simplistic and only handles simple method requirements, which it does by emitting a `switch` instruction to pick between the different cases. * A new IR pass was introduced to "desugar" any tagged union types used in the code. The downstream HLSL and GLSL compilers don't support `union`s, so we have to instead emit a tagged union as a "bag of bits" and implement loading the data for particular cases from it manually. * Final code emit mostly Just Works after the above steps, but we had to introduce an explicit IR instruction for bit-casting to handle the output of the desugaring pass. There are a bunch of gaps and caveats in this implementation, but that seems reasonable for something that is an experimental feature. The various `TODO` comments and assertion failures in unimplemented cases are intended, so that this work can be checked in even if it isn't feature-complete. * fixup: missing files * fixup: typos