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2020-02-11Small improvements around List (#1216)jsmall-nvidia
* * Improved fastRemoveAt * Fixed off by one bug * Fixed const safeness with List<> * Made List begin and end const safe. * Revert to previous RefPtr usage. * Fix bug with casting. * Tabs -> spaces. Small fixes/improvements to List. * Improve comment on List. * hasContent -> isNonEmpty
2020-02-06Improve checks and diagnostics around redeclarations (#1201)Tim Foley
* Improve checks and diagnostics around redeclarations This change turns checking for redeclarations into a dedicated phase of semantic checking, and ensures that it applies to the main categories of declarations: functions, types, and variables. Note that "variables" here includes function parameters and `struct` fields in addition to the more obvious global and local variables. Some of the logic for checking redeclarations already existed for functions, and was refactored to deal with other cases of declarations. The checking for functions still needs to be special-cased because functions are much more flexible about the kinds of redeclarations that are allowed. In addition to improving the diagnosis of redeclaration itself, this change also changes the error message that is produced when referencing a symbol that is ambiguous due to begin redeclared. This is a small quality-of-life fix, and has the benefit of being much easier to implement than robust tracking of what variables have had redeclaration errors issued so that we can skip emitting an ambiguity error at the use site. A new test case was added to cover the redeclaration cases for variables (but not types or functions), and the test for function parameters was updated to account for the new more universal diagnostic message (since function parameters used to have special-case redeclaration checking). * fixup: missing file
2019-12-06Add a custom RTTI implementation for the AST (#1148)Tim Foley
* Add a custom RTTI implementation for the AST Profiling was showing that the internal routines behind `dynamic_cast` were the worst offenders in the whole codebase, and a lot of this was being driven by casting inside the semantic checking logic. This change takes advantage of the fact that we *already* had a custom RTTI structure built up for the classes of syntax nodes that was previously being used to implement string->class lookup and factory services to support "magic" types and modifier in the stdlib (e.g., the way that a modifier declaration in the stdlib just lists the *name* of a C++ class that should be instantiated for it). That RTTI information already included a pointer from each syntax class to its base class (if any), based on the restriction that the AST node types form a single-inheritance hierarchy. The existing code already had a virtual `getClass()` routine on AST nodes, and an `isSubClassOf` query on the class information. Putting those pieces together to implement the `dynamicCast` and `as` routines was a cinch. The work in previous PRs to layer an abstraction over all the existing `dynamic_cast` call sites and to support type-specific `dynamicCast` implementations inside `RefPtr<>` pays off greatly here. * fixup: refactor implementation to appease more pedantic/correct compilers
2019-11-22Clean up the concept of "pseudo ops" (#1136)Tim Foley
* Clean up the concept of "pseudo ops" Built-in functions in the Slang standard library can be marked with `__intrinsic_op(...)` to indicate that they should not lower to functions in the IR, and that instead call sites to those functions should be translated directly to the IR. There are two cases where `__intrinsic_op(...)` gets used: 1. In the case where the argument to `__intrinsic_op(...)` is an actual IR instruction opcode, the IR lowering logic directly translates a call into an instruction with the given opcode. The arguments to the call become the operands of the instruction. 2. In the case where the argument to `__intrinsic_op(...)` is one of a set of "pseudo" instruction opcodes, the IR lowering logic directly handles the lowering to IR with dedicated code. The operands to the call might be handled differently depending on the kind of operation. The compound operators like `+=` are the most important example of these "pseudo" instructions. It doesn't make sense to handle them as true function calls (although that would work semantically), nor does it make sense to have a single IR instruction with such complicated semantics. An earlier version of the compiler used the same enumeration for both the true IR instruction opcodes and these "pseudo" opcodes, with the simple constraint that the pseudo opcodes were all negative while the real opcodes were positive. That design got changed up over a few refactorings, and because there was never a good explanation in the code itself of what "pseudo" opcodes were, we eventually ended up in a place where the in-memory and serialized IR encodings included logic to try to deal with the possibility of these "pseudo" opcodes, even though the entire design of the lowering pass meant that they'd never appear in generated IR. This change tries to clean up the mess in a few ways: * The terminology is now that these are "compound" intrinsic ops, to differentiate them from the more common case of intrinsic ops that map one-to-one to IR instructions. * The declaration of the compound intrinsic ops is no longer in a file related to the IR, and doesn't use the `IR` naming prefix, so somebody looking at the IR opcodes cannot become confused and think the compound ops are allowed there. * The IR encoding in memory and when serialized is updated to not account for or worry about the possibility of "pseudo" ops. * The compound ops are declared in such a way that ensures their enumerant values are all negative, so that they are yet again trivially disjoint from the true IR opcodes. A more drastic change might have split `__intrinsic_op` into two different modifier types: one for the trivial single-instruction case and one for the compound case. Doing this would make the change more invasive, though, because there are places in the meta-code that generates the standard library that intentionally handle both single-instruction and compound ops (because built-in operators can translate to either case). * fixup: missing file * cleanups based on review feedback
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
2019-11-18Further refactoring of semantic checking (#1102)Tim Foley
* Split apart `SemanticsVisitor` The existing `SemanticsVisitor` type was the visitor for expressions, statements, and declarations, and its monolithic nature made it hard to introduce distinct visitors for different phases of checking (despite the fact that we had, de facto, multiple phases of declaration checking). This change splits up `SemanticsVisitor` as follows: * There is nosw a `SharedSemanticsContext` type which holds the shared state that all semantics visiting logic needs. This includes state that gets mutated during the course of semantic checking. * The `SemanticsVisitor` type is now a base class that holds a pointer to a `SharedSemanticsContext`. Most of the non-visitor functions are still defined here, just to keep the code as simple as possible. The `SemanticsVisitor` type is no longer a "visitor" in any meaningful way, but retaining the old name minimizes the diffs to client code. * There are distinct `Semantics{Expr|Stmt|Decl}Visitor` types that have the actual `visit*` methods for an appropriate subset of the AST hierarchy. These all inherit from `SemanticsVisitor` primarily so that they can have easy access to all the helper methods it defines (which used to be accessible because these were all the same object). Any client code that was constructing a `SemanticsVisitor` now needs to construct a `SharedSemanticsContext` and then use that to initialize a `SemanticsVisitor`. Similarly, any code that was using `dispatch()` to invoke the visitor on an AST node needs to construct the appropriate sub-class and then invoke `dispatch()` on it instead. This is a pure refactoring change, so no effort has been made to move state or logic onto the visitor sub-types even when it is logical. Similarly, no attempt has been made to hoist any code out of the common headers to avoid duplication between `.h` and `.cpp` files. Those cleanups will follow. The one cleanup I allowed myself while doing this was getting rid of the `typeResult` member in `SemanticsVisitor` that appears to be a do-nothing field that got written to in a few places (for unclear reasons) but never read. * Remove some statefulness around statement checking Some of the state from the old `SemanticsVisitor` was used in a mutable way during semantic checking: * The `function` field would be set and the restored when checking the body of a function so that things like `return` statements could find the outer function. * The `outerStmts` list was used like a stack to track lexically surrounding statements to resolve things like `break` and `continue` targets. Both of these meant that semantic checking code was doing fine-grained mutations on the shared semantic checking state even though the statefullness wasn't needed. This change moves the relevant state down to `SemanticsStmtVisitor`, which is a type we create on-the-fly to check each statement, so that we now only need to establish the state once at creation time. The list of outer statements is handled as a linked list threaded up through the stack (a recurring idiom through the codebase). There was one place where the `function` field was being used that wasn't strictly inside statement checking: it appears that we were using it to detect whether a variable declaration represents a local, so I added an `_isLocalVar` function to serve the same basic purpose. With this change, the only stateful part of `SharedSemanticsContext` is the information to track imported modules, which seems like a necessary thing (since deduplication requires statefullness). * Refactor declaration checking to avoid recursion The flexiblity of the Slang language makes enforcing ordering on semantic checking difficult. In particular, generics (including some of the built-in standard library types) can take value arguments, so that type expressions can include value expressions. This means that being able to determine the type of a function parameter may require checking expressions, which may in turn require resolving calls to an overloaded function, which in turn requires knowing the types of the parameters of candidate callees. Up to this point there have been two dueling approaches to handling the ordering problem in the semantic checking logic: 1. There was the `EnsureDecl` operation, supported by the `DeclCheckState` type. Every declaration would track "how checked" it is, and `EnsureDecl(d, s)` would try to perform whatever checks are needed to bring declaration `d` up to state `s`. 2. There was top-down orchestration logic in `visitModuleDecl()` that tried to perform checking of declarations in a set of fixed phases that ensure things like all function declarations being checked before any function bodies. Each of these options had problems: 1. The `EnsureDecl()` approach wasn't implemented completely or consistently. It only understood two basic levels of checking: the "header" of a declaration was checked, and then the "body," and it relied on a single `visit*()` routine to try and handle both cases. Things ended up being checked twice, or in a circular fashion. 2. Rather than fix the problems with `EnsureDecl()` we layered on the top-down orchestration logic, but doing so ignores the fact that no fixed set of phases can work for our language. The orchestration logic was also done in a relatively ad hoc fashion that relied on using a single visitor to implement all phases of checking, but it added a second metric of "checked-ness" that worked alongside `DeclCheckState`. This change strives to unify the two worlds and make them consistent. One of the key changes is that instead of doing everything through a single visitor type, we now have distinct visitors for distinct phases of semantic checking, and those phases are one-to-one aligned with the values of the `DeclCheckState` type. More detailed notes: * Existing sites that used to call `checkDecl` to directly invoke semantic checking recursively now use `ensureDecl` instead. This makes sure that `ensureDecl` is the one bottleneck that everything passes through, so that it can guarantee that each phase of checking gets applied to each declaration at most once. * The existing `visitModuleDecl` was revamped into a `checkModule` routine that does the global orchestration, but now it is just a driver routine that makes sure `ensureDecl` gets called on everything in an order that represents an idealized "default schedule" for checking, while not ruling out cases where `ensureDecl()` will change the ordering to handle cases where the global order is insufficient. * Because `checkModule` handles much of the recursion over the declaration hierarchy, many cases where a declaration `visit*()` would recurse on its members have been eliminated. The only case where a declaration should recursively `ensureDecl()` its members is when its validity for a certain phase depends on those members being checked (e.g., determining the type of a function declaration depends on its parameters having been checked). * All cases where a `visit*()` routine was manually checking the state/phase of checking have been eliminated. It is now the responsibility of `ensureDecl` to make sure that checking logic doesn't get invoked twice or in an inappropriate order. * Most cases where a `visit*()` routine was manually *setting* the `DeclCheckState` of a declaration have been eliminated. The common case is now handled by `ensureDecl()` directly, and `visit*()` methods only need to override that logic when special cases arise. E.g., when a variable is declared without a type `(e.g., `let foo = ...;`) then we need to check its initial-value expression to determine its type, so that we must check it further than was initially expected/required. * This change goes to some lengths to try and keep semantic checking logic at the same location in the `slang-check-decl.cpp` file, so each of the per-phase visitor types is forward declared at the top of the file, and then the actual `visit*()` routines are interleaved throughout the rest of the file. A future change could do pure code movement (no semantic changes) to arrive at a more logical organization, but for now I tried to stick with what would minimize the diffs (although the resulting diffs can still be messy at times). * One important change to the semantic checking logic was that the test for use of a local variable ahead of its declaration (or as part of its own initial-value expression) was moved around, since its old location in the middle of the `ensureDecl` logic made the overall flow and intention of that function less clear. There is still a need to fix this check to be more robust in the future. * Add some design documentation on semantic checking The main thing this tries to lay out is the strategy for declaration checking and the rules/constraints on programmers that follow from it. * fixup: typos found during review
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
2019-07-09WIP: slang to C++ code generation (#997)jsmall-nvidia
* WIP: Emitting Cpp * Added HLSLType instead of using IRInst - because they don't seem to be deduped. * Removed need for lexer to take a String. Added mechansim to lookup intrinsic functions on C++. * A c/c++ cross compilation test. * WIP Cpp output using cloning and slang types. * More work to generate mul funcs. * WIP: Outputting some simple C++. * Expose findOrEmitHoistableInst to IRBuilder to aid cloning, * Simplification for checking for BasicTypes. Test infrastructure compiles output C++ code. * Dot and mat/vec multiplication output. * First pass at swizzling. * First support for binary ops. * Builtin binary and unary functions. * Any and all. * WIP adding support for other functions. Added code to generate function signature. * Add scalar functions to slang-cpp-prelude.h * Support for most built in operations. * Tested first ternary. * Checking the emitting of corner cases functions - normalize, length, any, all, normalize, reflect. * Check asfloat etc work. * Fmod support. * WIP Array handling in C++. * First stage in being able to handl arbitrary type output for CLikeSourceEmitter * Removed Handler/Emitter split - so can implement more easily complex type naming. * Array passing by value first pass. * Rename Array -> FixedArray * Outputs structs in C++. * Emit the thread config. * Dimension -> TypeDimension * SpecializedOperation -> SpecializedIntrinsic Operation -> IntrinsicOp Use shared impl of isNominalOp Commented use of m_uniqueModule etc. * Add code to test slang->cpp when compiled doesn't have errors. Does so by building shared library and exporting the entry point. * Fix linux clang/gcc compile error about override not being specified. * Make sure c-cross-compile is run on linux targets/smoke. * Remove c-cross-compile.slang from smoke. * Fix running tests/cross-compile/c-cross-compile.slang on Ubuntu 16.04 * Only add -std=c++11 for C++ source.
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.