| Age | Commit message (Collapse) | Author |
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* Use integer RTTI/witness handles in existential tuples.
* Fix clang error.
* Fix IR serialization to use 16bits for opcode.
* Undo accidental comment change.
* Use variable length encoding for opcode.
* Fix compile error.
* Fixing issues
* Fix code review issues.
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In some cases, functionality is available as either a GLSL extension for Vulkan/SPIR-V, or through the NVAPI system for D3D. This situation creates complications because while GLSL extensions are generally all supported by the open-source glslang compiler (which we can bundle and ship), NVAPI operations are exposed through a specific header (`nvHLSLExtns.h`) that ships as part of the NVAPI SDK.
When a user wants to explicitly use NVAPI-provided operations in their shader code, there are no major complications for Slang; the user sets up their include paths, `#include`s the relevant header, calls functions in it, and lets Slang deal with the details of compilation.
The challenge for Slang arises when we want to provide a cross-platform interface in our standard library (e.g., the `RWByteAddressBuffer.InterlockedAddF32` method that was recently added) that uses either a GLSL extension (when compiling for Vulkan/SPIR-V) or an NVAPI (when compiling to DXBC or DXIL). In that case, the code *generated* by Slang now has a dependency on NVAPI, and we need to somehow emit a `#include` directive that pulls it in when invoking fxc or dxc. Because we do not (and seemingly cannot) bundle the NVAPI header with the compiler, we have to rely on ther user to have it available and to somehow communicate to Slang where it is.
Exposing portable routines that sometimes use NVAPI currently creates two main challenges:
1. The user is forced to interact with the "prelude" mechanism in the compiler, which allows the programmer to define code in a given target language that gets prepended to the Slang-generated code. While the prelude mechanism is powerful, it is also hard for users to integrate into their workflow, and our experience so far is that users want something that Just Works.
2. If the user writes code that uses some of our abstract operations that layer on NVAPI *and* they also want to use NVAPI explicitly, they end up with two copies of the NVAPI header (one included by the Slang front-end, and another included by the downstream fxc/dxc compiler). This puts the user in the situation of (a) having to ensure that they set the defines like `NV_SHADER_EXTN_SLOT` consistently both when invoking Slang and when adding their prelude, and (b) even if they do make the definitions consistent, they run into the problem that fxc/dxc complain about overlapping register bindings on the two copies of the `g_NvidiaExt` global shader paraemter that the NVAPI header declares.
This change attempts to resolve both issues by adding a lot of "do what I mean" logic to the compiler to try to ease things in the common case. In particular:
1. The user no longer needs to use the "prelude" mechanism when using NVAPI. The compiler now embeds a default prelude for HLSL output, which will `#include` the NVAPI header if and only if the generated code needs NVAPI access because of portable standard library routines that were used.
2. The user can mix-and-match explicit NVAPI use and stdlib functions that compile to use NVAPI. The register/space to be used by NVAPI when included via prelude is now set based on whatever the user set via the preprocessor so that it should automatically be consistent between both cases. Furthermore, the code we emit for the declaration of `g_NvidiaExt` when compiling explicit NVAPI use is set up to be conditional, so that it is skipped in the case where the prelude will pull in its own declaration of that parameter.
The way all this is achieved involves a lot of moving pieces:
* We now have an HLSL prelude, which mostly just serves to `#include "nvHLSLExtns.h"` in the case where NVAPI support is needed downstream.
* Standard library operations that require NVAPI for their implementation on HLSL include a new `[__requiresNVAPI]` attribute.
* The preprocessor has been extended so that after tokenizing an input file it looks up the NVAPI-relevant macros in the resulting environment, and if they are set it attached a modifier (`NVAPISlotModifier1) to the AST `ModuleDecl` that is based on their values. Logic is added to detect if multiple input files specify values for the macros in ways that conflict.
* The semantic checking step is extended so that it detects the "magic" NVAPI declarations (the `g_NvidiaExt` paramter and the `NvShaderExtnStruct` type that it uses) and attaches a modifier to them so that they can be identified as such in later steps.
* Parameter binding is extended to collect a list of the AST modifiers that reflect NVAPI binding, and to reserve the relevant register(s) so that ordinary user-defined parameters cannot conflict with them.
* IR lowering translates the three new AST modifiers related to NVAPI over to IR equivalents.
* IR linking is extended to make sure that it clones any `IRNVAPISlotDecoration`s attached to the input modules. The pass intentionally does not care where the modifiers came from; it just collects them all and leaves it to downstream code to sort out what they mean.
* Emit logic is extended to have a notion of "prelude directives" which are preprocessor directives that should come *before* the prelude in the generated code, because they can impact the way that the prelude compiles. This is done so that we don't have to introduce ad hoc logic for each downstream compiler to set any relevant `-D` flags (e.g., both fxc and dxc would need to duplicate such logic for NVAPI support).
* The HLSL source emitter is extended to track whether it emits any operations that require NVAPI support.
* The HLSL source emitter is extended to emit prelude directives based on whether NVAPI is needed and, if it is, to also set the register and space that NVAPI should use based on what was stored in the decoration(s) on the IR module.
* The HLSL source emitter is extended so that it detects global instructions that represent "magic" NVAPI constructs , and emit them as conditional definitions so that they are skipped when NVAPI is included via the prelude.
* The handling of requires capabilities during emit logic was cleaned up a bit so that more logic is shared across targets, and also so that the same logic is used both when emitting a function declaration/definition and when emitting a call to an instrinsic function (which won't get declared/defined).
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* Front-load cuda module loading to fill in RTTI pointers.
* Enable dynamic dispatch codegen for CUDA.
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A long-standing problem for the Slang implementation has been that some targets (notably GLSL/SPIR-V) do not support treating resources (textures, buffers, samplers, etc.) as first-class types. Resource types on such platforms are restricted so that they may not be used as the type of:
1. fields of aggregate types (`struct`s)
2. local variables
3. function results or `out`/`inout` parameters
Issue (1) is handled by our "type legalization" pass today, by splitting aggregates that contain resources into separate fields/variables/parameters. Issue (2) is worked around by putting code into SSA form and promoting local variables to SSA temporaries when possible; the net result is that many local variables of texture type are eliminated (that pass is not perfect, though, and it is possible for users to get errors when it doesn't fully clean up local variables of texture type).
Issue (3) is a much more complicated matter, and it is what this change is concerned with.
A typical solution to issue (3) is to simply inline all of the code in a program, at which point function results and `out`/`inout` parameters will no longer exist to cause problems. We reject such solutions for two reasons. First, there are limitations on control-flow structure in HLSL/GLSL/SPIR-V that mean they cannot express certain programs after inlining has been performed. Second, and more importantly, the philosophy of the Slang compiler is to perform as little duplication of code as possible, so that we do not accidentally contribute to binary size bloat.
Instead, this change tackles the problem of functions that output resource types by adding a new specialization pass. The pass detects functions that ought to be specialized (because they have resource-type outputs), and inspects their bodies to see if the values they output have a predicatable structure that can be replicated outside of the function body. The same logic that inspects the function body also rewrites (a copy of) the function to not have the offending outputs. Finally, all the call sites to a function that is rewritten in this way also get rewritten so that instead of using output values from the function itself, they reproduce the expected output value(s) in their own code.
The pass as presented here is intentionally limited in the scope of what it can optimize away (and the test case only touches on that specific functionality). The goal is to get a basic version of this pass in place and evaluated, and then to expand on its functionality incrementally over time.
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* Allow mixing unspecialized and specialized existential parameters.
* Fixes.
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* Enable lower-generics pass universally.
* Exclude builtin interfaces and functions from lower-generics pass.
* Update stdlib.
* Fixup.
* Fixes handling of nested intrinsic generic functions.
* Fixes.
* Fixes.
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* Tuple types.
* Fix x86 warning
* Improved deduplication
Co-authored-by: Tim Foley <tfoleyNV@users.noreply.github.com>
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* AnyValue based dynamic code gen
* Fix aarch64 build error
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The Big Picture
===============
Given input Slang code like:
```hlsl
Texture2D gA;
[shader("compute")]
void kernelFunc(uniform Texture2D b, uint3 tid : SV_DispatchThreadID)
{ ... }
```
the existing CUDA code generation strategy would always generate a kernel with a signature like:
```c++
struct GlobalParams { Texture2D gA; }
struct EntryPointParams { Texture2D b; }
extern "C" __global__
void kernelFunc(EntryPointParams* entryPointParams, GlobalParams* globalParams)
{ ... }
```
This choice was consistent with the conventions of the CPU kernel target, and shares the advantage that it is easy for the user to data-drive the logic for filling in parameters and then invoking a kernel.
However, the approach outlined above has two serious problems when used for CUDA kernels:
* First, it defies the programmer's expectation about what an "equivalent" CUDA kernel signature would be, which makes it awkward for a developer to invoke this kernel from CUDA C++ host code (especially in the context of an app that might also run hand-written CUDA kernels).
* Second, the performance of this approach suffers because every access to a global or entry point parameter turns into a load from global memory. In contrast, a typical hand-written CUDA kernel passes its parameters via an implementation-specific path that (for current CUDA platforms) seems to be equivalent to `__constant__` memory in performance.
This change alters the convention so that the Slang compiler takes the code from the top of this message and translates it into something like:
```c++
struct GlobalParams { Texture2D gA; }
__constant__ GlobalParams SLANG_globalParams;
extern "C" __global__
void kernelFunc( Texture2D b )
{ ... }
```
This translation alleviates both problems with the current translation:
* The signature of the generated CUDA kernel function is as close to that of the original as is possible (we had to eliminate the `SV_*`-semantic varying inputs), and should directly match what the programmer would expect in common cases.
* Entry-point parameters are passed via CUDA kernel parameters, and should thus match in performance. Global parameters are passed via a variable in `__constant__` memory, and thus should also perform as well as possible/expected.
Detailed Changes
================
* Disable the `collectEntryPointUniformParams` pass for CUDA, so that entry-point `uniform` parameters are *not* bundles into a single `struct` and/or `ConstantBuffer`.
* When targeting CUDA, disable the logic for generating an entry-point parameter for passing in the global shader parameter(s)
* Allow `CLikeSourceEmitter` subclasses to override the name generated for entry-point symbols, and use this to add the required prefix for each OptiX kernel type when translating a ray-tracing kernel.
* Add logic to emit "parameter groups" in a specialized way for CUDA (this is the same approach that allows us to generate `cbufffer { ... }` declarations for fxc). A global-scope parameter group will turn into a global `__constant__` variable called `SLANG_globalParams` (that name becomes part of the ABI for Slang-compiled shaders).
* Update the logic in `render-test` for loading and invoking CUDA kernels to handle the new policy.
The last bullet there merits expansion, since it is indicative of the work a client using Slang would have to go through to use our generated kernels with the new policy:
* When loading a CUDA module with one or more kernels, we also use `cuModuleGetGlobal` to query the address of the `SLANG_globalParams` symbol in that CUDA module. That pointer needs to be used when setting global parameter values to be used by kernels in that CUDA odule.
* Because our existing `BindPoint` logic for CUDA always sets up parameter data in GPU memory, we end up having to copy the entry-point parameter data from GPU memory to host memory. This step would ideally be skipped in a codebase that understands the correct policy, but it is a bit unfortunate that it is no longer trivially correct for an application to store all parameter data in GPU memory.
* Before invoking the kernel, we need to use a `cudaMemcpyAsync` to copy from the prepared GPU memory for global parameters over to the `SLANG_globalParams` symbol associated with the kernel to be invoked. Because this operations is issued on the same CUDA stream as the kernel call, it is guaranteed to not overlap with GPU kernel execution.
* When invoking the kernel, we take advantage of the seldom-used `CU_LAUNCH_PARAM_BUFFER_POINTER` facility to specify a contiguous memory region with all the entry-point parameters in it instead of passing each entry-point parameter separately. Given Slang reflection it is also possible to query the offset of each entry-point parameter in the buffer, so we could invoke the kernel in the traditional fashion as well. The choice here is up to the application.
Caveats
=======
* This is a breaking change, and any subsequent release will need to reflect that fact. Any customers who rely on Slang's current CUDA codegen strategy are likely to be surprised by this change, and I don't see an easy way to give them a more gentle transition.
* This change does *not* remove the logic that introduces a `KernelContext` type for code that requires it. That means that things like `static` global variables can continue to work on CUDA for now, but we know that those are not going to be something we can support in the long-term with separate compilation.
* While the policy implemented in this change is a reasonable default, it is still not going to perfectly match expecations for some developers. In particular, some developers who are familiar with both D3D and CUDA will likely wonder why a global `cbuffer` in Slang translates to a global-memory pointer in the output CUDA instead of one global `__constant__` variable per `cbuffer`. A more detailed alternate translation would generate a distinct global `__constant__` variable for each top-level constant buffer or parameter block. We may need to refine the translation even more based on feedback from users who care about how we handle global-scope parameters.
* Recent changes in Slang have broken the logic that handles the OptiX "shader record" as an alternative mechanism for passing entry-point parameters. In order to get any level of OptiX support up and running we will have to change the IR passes that run on CUDA kernels to actually run the "collection" of `uniform` parameters for ray tracing stages, and then to replace references to the resulting parameter with a call to the function to access the shader record.
* The use of `SLANG_globalParams` here works well enough in the case of whole-program compilation; every `CUmodule` ends up with (zero or) one parameter with this name, and an application can just hard-code it. As a mechanism it wouldn't work in the presence of separately-compiled modules that might introduce their own global parameters (including cases like constant lookup tables that really want to be at the global scope). An alternative approach would have Slang generate output PTX for each module, where a module has an optional global symbol for its own global-scope parameters (with a mangled name that is based on the module name), and then a linked CUDA binary has all of those distinct symbols. Such an approach would be compatible with module-at-a-time reflection and parameter binding, but would lead to another breaking change down the line for code that switches to `SLANG_globalParams`.
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* Ensure labels are dumped in `lower-to-ir`.
There is a `dumpIR` function that accepts a label parameter already in slang-emit.cpp. This change moves it to slang-ir.cpp so it may be called from other files.
* update expected test result
Co-authored-by: Yong He <yhe@nvidia.com>
Co-authored-by: Tim Foley <tfoleyNV@users.noreply.github.com>
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* Run array specialization in a sperate pass.
* rename specializeFunctionCall->specializeFunctionCalls
Co-authored-by: Tim Foley <tfoleyNV@users.noreply.github.com>
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* Multiple Entry Point Backend
This PR introduces changes to the IR linking, emitting, and options for
multiple entry points. Specifically, this PR updates several locations
to support a (potentially empty) list of entry points, adding list infrastructure and looping over entry points as appropriate.
* Formatting change
* Updated unknown target case to not require an entry point
* Formatting and list consts updates
Co-authored-by: Tim Foley <tfoleyNV@users.noreply.github.com>
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* Remove KernelContext wrapper from CPU/CUDA emit
Currently, the CPU and CUDA C++ targets rely on a `KernelContext` type that is generated during emit, as a way to provide implicit access to things that were global in the input Slang code, but that can't actually be emitted as globals in the target language (because the semantics of global declarations differ).
For example, input like:
```hlsl
ConstantBuffer<Stuff> gStuff; // shader parameter
groupshared int gData[1024]; // thread-group shared variable
static int gCounter = 0; // "thread-local" global-scope variable
void subroutine() { ... }
[shader("compute")] void computeMain() { ... }
```
would translate to output C++ for CPU a bit like:
```c++
struct KernelContext
{
ConstantBuffer<Stuff> gStuff;
int gData[1024];
int gCounter = 0;
void subroutine() { ... }
void computeMain() { ... }
};
```
Note that both `computeMain()` and `subroutine()` are non-`static` members functions on `KernelContext`, so they have an implicit `this` parameter of type `KernelContext`, which allows the bodies of those functions to implicitly reference `gStuff`, etc. by name in their bodies.
Because `KernelContext::computeMain()` is a member function, we end up emitting an additional global-scope function to expose the entry point to the outside world, and that function is responsible for declaring a local `KernelContext` and invoking the generated entry point on it.
This approach has several important drawbacks:
* It complicates the emit logic for CPU and CUDA, with many special cases around when/how things get emitted
* It complicates the implementation of dynamic dispatch, because what seems like a function pointer in Slang IR needs to be a pointer-to-member-function in C++.
* It makes it difficult to have a non-kernel-oriented mode of compilation for CPU where a Slang function with a given signature gets output as a C++ CPU function with the "same" signature (not wrapped up as a member function of `KernelContext`.
This change makes a step toward addressing these issues by making the introducing of the `KernelContext` type be something that is done in an explicit IR pass instead of being handled as part of the last-mile emit logic.
The most important change is the removal of code related to `KernelContext` from the `slang-emit-{cpp,cuda}.{h,cpp}` files, with the equivalent logic instead being handled in a new pass in `slang-ir-explicit-global-context.{h,cpp}`. It should be noted that further cleanups to the emit logic should now be possible; in particular, both the CPU and CUDA emit paths are manually sequencing the `EmitAction`s instead of relying on the default logic, but at this point they should be able to just use the default. The additional cleanups are left for future work.
The explicit IR pass does more or less what one would expect: it identifies global-scope entities (global variables and parameters) that need to be wrapped and turns them into fields of a `KernelContext` type. It then modifies all entry points to initialize a `KernelContext` as part of their startup. Finally, any code that used to refer to the global entities is changed to refer to a field of the context, with the context passed via new function parameters (the new parameter is only added to functions that need it for now).
Transforming global variables into fields of a `KernelContext` type in the IR pass ends up dropping their initial-value expressions (since those were attached as basic blocks on the `IRGlobalVar`). To avoid breaking code that relies on global-scope (but thread-local) variables, this change also adds an explicit pass that takes the initialization logic on all global variables and moves it to explicit logic that runs at the start of every entry point in a linked module (`slang-ir-explicit-global-init.{h,cpp}`). This pass would also be useful when we get back to direct SPIR-V emit, since SPIR-V also requires initialization logic for globals to be emitted into entry points.
One complication that arises when the IR is introducing the types for entry-point parameters, global-scope parameters, and the `KernelContext` type is that it becomes harder for the emit logic to utter the names of those types (they might not even have names, since `IRNameHint`s might get stripped). This created a problem since the wrapper operations that were being generated for CPU were taking `void*` parameters and casting them to the appropriate type. To work around this issue, we have added an explicit IR pass (`slang-ir-entry-point-raw-ptr-params.{h,cpp}`) that transforms the signature of entry points so that any pointer parameters instead become raw pointer (`void*`) parameters, with the casting being handled inside the entry point itself.
One consequence of all the above changes is that for the CUDA target we no longer need a wrapper function to invoke the generated entry point any more, because the IR function for the entry point ends up having the correct/expected signature already. This is also the case for CPU when it comes to the `*_Thread` wrapper function, but this change doesn't try to eliminate the wrapper because of a belief that the `*_Thread`-level interface is going away anyway.
Because the IR is now responsible for ensuring the signature of the IR entry point for CUDA and CPU is what is expected, I needed to modify the `slang-ir-entry-point-uniforms` pass to always create an explicit parameter for the entry point uniforms when compiling for CUDA/CPU, even if there were no `uniform` parameters on the entry point as written. This also ended up requiring some tweaks to the parameter layout logic to ensure that CPU/CUDA targets always treat `ConstantBuffer<T>` as a `T*` even in the case where `T` is an empty `struct` type (which happens when we construct a `struct` type to represent the uniform parameters of an entry point with no uniform parameters...).
There are several future changes that can/should build on this work:
* We should change the generated signatures for CUDA kernels, so that they don't rely on `KernelContext` for global-scope parameters. At that point we can avoid generating a `KernelContext` at all for CUDA, except when a program uses global-scope thread-local variables.
* We should figure out how to make the "ABI" for dynamic-dispatch calls ensure that the kernel context is either always passed, or always *not* passed. Making a hard-and-fast rule as part of the calling convention for dynamic calls would ensure that they access through the context continues to work with dynamic calls (this change might break it in some cases).
* We should figure out how to handle the layout for the `KernelContext` in cases where a program is composed of multiple separately-compiled modules. Right now the layout of the `KernelContext` requires global knowledge (as does the pass that introduces explicit initialization for global-scope thread-locals).
* We should try to further clean up the CPU/CUDA C++ emit logic to fall back on the default emit behavior more, now that the various special-case approaches that were taken are no longer needed
* fixup: restore build files to default configuration
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The main change here is that the CPU and CUDA C++ emit paths now rely on an earlier IR pass to legalize the varying parameter list of a kernel and translate references to varying parameters with semantics like `SV_DispatchThreadID`. Doing so removes a lot of special-case logic from the emit passes.
This work moves us even closer to being able to eliminate `KernelContext` from the CPU/CUDA emit logic, because it removes the issue of state related to varying inputs being stored in `KernelContext`.
The new pass that handles the legalization is in `slang-ir-legalize-varying-params.cpp`, and it borrows heavily from the existing `slang-ir-glsl-legalize.cpp` pass. The new pass factors out the target-independent and target-dependent logic, so that both CPU and CUDA can share much of the same code despite having very different rules for how the system-value parameters are being provided.
An eventual goal is to have the new pass also handle the GLSL case, but doing so requires copying even more logic out of the GLSL-specific pass, and doing so seemed like a step to far for what was meant to be a stepping-stone change as part of other work. As a result of the incomplete nature of the pass, certain cases don't work for compute shader inputs for CPU/CUDA (e.g., wrapping your varying inputs in a `struct` type parameter), but those were cases that also didn't work in the existing `emit`-based logic.
One major consequence of this change is that the logic for emitting the various different functions that represent an entry point for our CPU back-end has been streamlined and simplified. The original logic had a fair bit of cleverness built in to try and avoid unnecessary math ops when computing the various IDs/indices, while the new logic is much more simplistic (the main dispatch function loops over threadgroups with a triply-nested `for` and then delegates to the group-level function loops over threads with its own nested `for`s).
Longer term, it will be important to simplify the CPU functions we emit further, by eliminating things like the `_Thread` function that should never really be exposed to users (the minimum granularity of invoking a CPU compute kernel should be a single threadgroup). We may eventually decide to synthesize all of the extra code that is being generated in the `emit` pass as IR instead.
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* Adding support for global uniform shader parameters
This change adds support for Slang programmers to declare shader parameters of "ordinary" types at global scope:
```hlsl
uniform float gScaleFactor;
void main() { ... *= gScaleFactor; ... }
```
The generated HLSL/GLSL/DXIL/SPIR-V output will be something along the lines of:
```hlsl
struct GlobalParams
{
float gScaleFactor;
}
cbuffer globalParams
{
GlobalParams globalParams;
}
void main() { ... *= globalParams.gScaleFactor; ... }
```
The binding information used for the implicit `globalParams` constant buffer will be determined by the existing implicit parameter binding logic (which already had support for this kind of transformation).
The reason this change is being pursued right now is because it is one step toward removing the implicit `KernelContext` type that is used to wrap the generated code for our CPU and CUDA C++ targets. Handling global-scope parameters of ordinary type requires an IR pass that synthesizes the `GlobalParams` structure type above, and that step ends up removing the need for the similar `UniformState` structure that was being used in the CPU/CUDA emit logic.
A more detailed guide to the changes included follows:
* The diagnostic for a global-scope variable that is implicitly a shader parameter was kept, but changed to a warning. Users can opt out of the warning by decorating their parameter as a `uniform` (since that keyword is already being used to mark entry-point parameters that should be treated as uniform shader parameters).
* To simplify the task of finding the global shader parameters, the `CLikeSourceEmitter` type has been given an `m_irModule` member. The previous emit logic for `UniformState` was having to do a roundabout solution involving the `EmitAction`s to deal with not having direct access to the module.
* Removed a few dead declarations in the emit logic (related to a much earlier point where emit was based on the AST instead of the IR).
* Made the computation of type names in C++ emit take into account `ConstantBuffer<T>` and `ParameterBlock<T>`. As far as I can tell, these were being handled with some special-case hacks in the emit logic instead of being supported more fundamentally. It might actually be good to pass these through as `ConstantBuffer<T>` and `ParameterBlock<T>` in the C++ output, and allow the prelude to customize their translation (defaulting to defining them as `T*`).
* Removed the special-case C++ emit logic for references to global shader parameters. There are now at most two global shader parameters to deal with, and the default emit logic (referring to them by name) does the Right Thing.
* Changed the handling of entry points for C++ (both CPU and CUDA) so that it handles the bundled-up shader paameters for the global and entry-point scopes the same way. The main complication here is OptiX, where parameter data is passed very differently than it is for CUDA compute kernels.
* Reverted changes to `ir-entry-point-uniforms` that had made its logic depend on the compilation target. The parameter binding logic was already responsible for deciding if a given target needed to wrap up its entry-point parameters in a constant buffer, and the IR pass was respecting that layout information. The current workaround had been removing the `ConstantBuffer<T>` indirection from this IR pass for CPU/CUDA, but then reintroducing the same indirection later on in the emit step.
* Added an explicit IR pass with the task of collecting global-scope parameters of uniform/ordinary type and packaging them up into a `struct`, and then optionally packaging that `struct` up in a constant buffer. This pass bases its decisions on the IR layout information that was already computed, so it should match whatever policy choices were made at the layout level.
* Changed the "key" operand on IR `struct` layout information to not assume an `IRStructKey`. The problem here is that the global scope gets a `StructTypeLayout` to represent its members, and this is convenient (rather than having to always special-case logic that handles the global scope), but the "fields" of that struct are global variables which do not have `IRStructKey`s associated with them. The simplest solution is to use the variables themselves as the keys, which required removing the assumption in the IR encoding.
* Updated the IR layout process to compute a layout for the global scope of an entire program, and to attach that to the `IRModule` via a decoration. Updated the IR linking process to carry through that decoration to the linked output. This is necessary so that the IR pass that transforms global parameters can access the global-scope layout information.
An important concern with this approach is that the contents and layout of the monolithic `GlobalParams` structure depends on the exact set of modules that were linked (and the order in which they were specified, in some cases). This isn't really a new thing with this change, but it becomes more important as we start to think of how to generalize things to better support separate compilation and linking.
There are changes that can (and should) be made to the way that IR layouts are computed for programs (e.g., so that we compute layout per-module and then combine them rather than as a whole-program step). In this case, the problem of forming the combined/linked global layout can be moved down the IR level and not be reliant on AST-level information.
Just changing the way layout and linking interact would not change the fundamental problem that global shader parameters as they currently exist in Slang/HLSL/GLSL are not readily compatible with true separate compilation. We either need to find a solution strategy that we can apply to allow existing shaders to work with separate compilation *or* we need to incrementally work toward removing support for global-scope shader parameters in favor of explicit entry-point parameters in all cases.
* fixup: missing files
* fixup: comment the new code
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* Multiple Entry Point Cleanup
This commit provides some in-code cleanup of the previous multiple entry point PR (#1411). Specifically, this PR provides refactoring of multiple entry point functions into helper functions, the removal of the EntryPointAndIndex struct, and various stylistic improvements.
* Minor updates
Co-authored-by: Tim Foley <tfoleyNV@users.noreply.github.com>
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(#1420)
* Fix handling of UniformState from #1396
* * Fix bug in slang-dxc-support where it didn't get the source path correctly
* Make entryPointIndices const List<Int>&
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* Backend for Multiple Entry Points
Introduces the basic backend on the compiler for zero or more entry
points. Entry points have been extended to lists for several functions,
with loopFunctions have been extended to take in entry points and
indices as appropriate, to allow for multiple entry points once the
frontend is expanded. Several functions are currently being assumed to
have a single entry point for simplicity and provide a work in progress
commit.
* Progress on debugging fixes
* Tests passing
* Refactored emitEntryPoints
* Updated lists to be by constant reference
* Fixes to formatting
* Refactoring updates for the compiler
* Fix for compilation errors
* Reformatting
* More reformatting
* Moved struct around to help with compilation
Co-authored-by: Tim Foley <tfoleyNV@users.noreply.github.com>
|
|
|
|
* Associate a downstream compiler for prelude lookup even if output is source.
* Remove LanguageStyle and just use SourceLanguage instread.
* Added set/getPrelude.
Made prelude work on source language.
* Fix typo in method name replacement.
get/SetPrelude get/setLanguagePrelude
* Fix issue because of method name change.
* Remove getPreludeDownstreamCompilerForTarget
|
|
* * Fix output in slang repro command line
* Profile uses lowerCamel method names (had mix of upper and lower)
* Rename slang-serialize-state/SerializeStateUtil to slang-repro and ReproUtil.
|
|
(#1395)
Co-authored-by: Tim Foley <tfoleyNV@users.noreply.github.com>
|
|
* Add IR pass to lower generics into ordinary functions.
* Fix project files
* Emit dynamic C++ code for simple generics and witness tables.
Fixes #1386.
* Remove -dump-ir flag.
* Fixups.
|
|
IRWitnessTable values (#1387)
* Generate IRType for interfaces, and use them as the type of IRWitnessTable values.
This results the following IR for the included test case:
```
[export("_S3tu010IInterface7Computep1pii")]
let %1 : _ = key
[export("_ST3tu010IInterface")]
[nameHint("IInterface")]
interface %IInterface : _(%1);
[export("_S3tu04Impl7Computep1pii")]
[nameHint("Impl.Compute")]
func %Implx5FCompute : Func(Int, Int)
{
block %2(
[nameHint("inVal")]
param %inVal : Int):
let %3 : Int = mul(%inVal, %inVal)
return_val(%3)
}
[export("_SW3tu04Impl3tu010IInterface")]
witness_table %4 : %IInterface
{
witness_table_entry(%1,%Implx5FCompute)
}
```
* Fixes per code review comments.
Moved interface type reference in IRWitnessTable from their type to operand[0].
* Fix typo in comment.
|
|
|
|
* Added GLSL_460 if ray tracing is used on fragment shader.
Moved GLSL specific setup init function.
* Split out _requireRayTracing method.
|
|
* Small improvements to documentation and code around DiagnosticSink
* Made methods/functions in slang-syntax.h be lowerCamel
Removed some commented out source (was placed elsewhere in code)
* Making AST related methods and function lowerCamel.
Made IsLeftValue -> isLeftValue.
|
|
* Synthesize "active mask" for CUDA
The Big Picture
===============
The most important change here is to `hlsl.meta.slang`, where the declaration of `WaveGetActiveMask()` is changed so that instead of mapping to `__activemask()` on CUDA (which is semantically incorrect) it maps to a dedicated IR instruction.
The other `WaveActive*()` intrinsics that make use of the implicit "active mask" concept had already been changed in #1336 so that they explicitly translate to call the equivalent `WaveMask*()` intrinsic with the result of `WaveGetActiveMask()`. As a result, all of the `WaveActive*()` functions are now no different from a user-defined function that uses `WaveGetActiveMask()`.
The bulk of the work in this change goes into an IR pass to replace the new instruction for getting the active mask gets replaced with appropriately computed values before we generate output CUDA code. That work is in `slang-ir-synthesize-active-mask.{h,cpp}`.
Utilities
=========
There are a few pieces of code that were helpful in writing the main pass but that can be explained separately:
* IR instructions were added corresponding to the Slang `WaveMaskBallot()` and `WaveMaskMatch()` functions, which map to the CUDA `__ballot_sync()` and `__match_any_sync()` operations, respectively. These are only implemented for the CUDA target because they are only being generated as part of our CUDA-only pass.
* The `IRDominatorTree` type was updated to make it a bit more robust in the presence of unreachable blocks in the CFG. It is possible that the same ends could be achieved more efficiently by folding the corner cases into the main logic, but I went ahead and made things very explicit for now.
* I added an `IREdge` utility type to better encapsulate the way that certain code operating on the predecessors/successors of an `IRBlock` were using an `IRUse*` to represent a control-flow edge. The `IREdge` type makes the logic of those operations more explicit. A future change should proably change it so that `IRBlock::getPredecessors()` and `getSuccessors()` are instead `getIncomingEdges()` and `getOutgoingEdges()` and work as iterators over `IREdge` values, given the way that the predecessor and successor lists today can contain duplicates.
* Using the above `IREdge` type, the logic for detecting and break critical edges was broken down into something that is a bit more clear (I hope), and that also factors out the breaking of an edge (by inserting a block along it) into a reusable subroutine.
The Main Pass
=============
The implementation of the new pass is in `slang-ir-synthesize-active-mask.cpp`, and that file attempts to include enough comments to make the logic clear. A brief summary for the benefit of the commit history:
* The first order of business is to identify functions that need to have the active mask value piped into them, and to add an additional parameter to them so that the active mask is passed down explicitly. Call sites are adjusted to pass down the active mask which can then result in new functions being identified as needing the active mask.
* The next challenge is for a function that uses the active mask, to compute the active mask value to use in each basic block. The entry block can easily use the active mask value that was passed in, while other blocks need more work.
* When doing a conditional branch, we can compute the new mask for the block we branch to as a function of the existing mask and the branch condition. E.g., the value `WaveMaskBallot(existingMask, condition)` can be used as the mask for the "then" block of an `if` statement.
* When control flow paths need to "reconverge" at a point after a structured control-flow statement, we need to insert logic to synchronize and re-build the mask that will execute after the statement, while also excluding any lanes/threads that exited the statement in other ways (e.g., an early `return` from the function).
The explanation here is fairly hand-wavy, but the actual pass uses much more crisp definitions, so the code itself should be inspected if you care about the details.
Tests
=====
The tests for the new feature are all under `tests/hlsl-intrinsic/active-mask/`. Most of them stress a single control-flow construct (`if`, `switch`, or loop) and write out the value of `WaveGetActiveMask()` at various points in the code.
In practice, our definition of the active mask doesn't always agree with what D3D/Vulkan implementations seem to produce in practice, and as a result a certain amount of effort has gone into adding tweaks to the tests that force them to produce the expected output on existing graphics APIs. These tweaks usually amount to introducing conditional branches that aren't actually conditional in practice (the branch condition is always `true` or always `false` at runtime), in order to trick some simplistic analysis approaches that downstream compilers seem to employ.
One test case currently fails on our CUDA target (`switch-trivial-fallthrough.slang`) and has been disabled. This is an expected failure, because making it produce the expected value requires a bit of detailed/careful coding that would add a lot of additional complexity to this change. It seemed better to leave that as future work.
Future Work
===========
* As discussed under "Tests" above, the handling of simple `switch` statements in the current pass is incomplete.
* There's an entire can of worms to be dealt with around the handling of fall-through for `switch`.
* The current work also doesn't handle `discard` statements, which is unimportant right now (CUDA doesn't have fragment shaders), but might matter if we decide to synthesize masks for other targets. Similar work would probably be needed if we ever have `throw` or other non-local control flow that crosses function boundaries.
* An important optimization opportunity is being left on the floor in this change. When block that comes "after" a structured control-flow region (which is encoded explicitly in Slang IR and SPIR-V) post-dominates the entry block of the region, then we know that the active mask when exiting the region must be the same as the mask when entering the region, and there is no need to insert explicit code to cause "re-convergence." This should be addressed in a follow-on change once we add code to Slang for computing a post-dominator tree from a function CFG.
* Related to the above, the decision-making around whether a basic block "needs" the active mask is perhaps too conservative, since it decides that any block that precedes one needing the active mask also needs it. This isn't true in cases where the active mask for a merge block can be inferred by post-dominance (as described above), so that the blocks that branch to it don't need to compute an active mask at all.
* If/when we extend the CPU target to support these operations (along with SIMD code generation, I assume), we will also need to synthesize an active mask on that platform, but the approach taken here (which pretty much relies on support for CUDA "cooperative groups") wouldn't seem to apply in the SIMD case.
* Similarly, the approach taken to computing the active mask here requires a new enough CUDA SM architecture version to support explicit cooperative groups. If we want to run on older CUDA-supporting architectures, we will need a new and potentially very different strategy.
* Because the new pass here changes the signature of functions that require the active mask (and not those that don't), it creates possible problems for generating code that uses dynamic dispatch (via function pointers). In principle, we need to know at a call site whether or not the callee uses the active mask. There are multiple possible solutions to this problem, and they'd need to be worked through before we can make the implicit active mask and dynamic dispatch be mutually compatible.
* Related to changing function signatures: no effort is made in this pass to clean up the IR type of the functions it modifies, so there could technically be mismatches between the IR type of a function and its actual signature. If/when this causes problems for downstream passes we probably need to do some cleanup.
* fixup: backslash-escaped lines
I did some "ASCII art" sorts of diagrams to explain cases in the CFG, and some of those diagrams used backslash (`\`) characters as the last character on the line, causing them to count as escaped newlines for C/C++.
The gcc compiler apparently balked at those lines, since they made some of the single-line comments into multi-line comments.
I solved the problem by adding a terminating column of `|` characters at the end of each line that was part of an ASCII art diagram.
* fixup: typos
Co-authored-by: jsmall-nvidia <jsmall@nvidia.com>
|
|
* Add support for generic load/store on byte-addressed buffers
Introduction
============
The HLSL `*ByteAddressBuffer` types originaly only supported loading/storing `uint` values or vectors of the same, using `Load`/`Load2`/`Load3`/`Load4` or `Store`/`Store2`/`Store3`/`Store4`. More recent versions of dxc have added support for generic `Load<T>` and `Store<T>`, which adds a two main pieces of functionality for users.
The first and more fundamental feature is that `T` can be a type that isn't 32 bits in size (or a vector with elements of such a type), thus exposing a capability that is difficult or impossible to emulate on top of 32-bit load/store (depending on what guarantees `*StructuredBuffer` makes about the atomicity of loads/stores).
The secondary benefit of having a generic `Load<T>` and `Store<T>` is that it becomes possible to load/store types like `float` without manual bit-casting, and also becomes possible to load/store `struct` types so long as all the fields are loadable/storable.
This change adds generic `Load<T>` and `Store<T>` to the Slang standard library definition of byte-address buffers, and tries to bring those same benefits to as many targets as possible. In particular, the secondary benefits become available on all targets, including DXBC: byte-address buffers can be used to directly load/store types other than `uint`, including user-defined `struct` types, so long as all of the fields of those types can be loaded/stored.
The ability to load/store non-32-bit types depends on target capabilities, and so is only available where direct support for those types is available. For 16-bit types like `half` this includes both Vulkan and D3D12 DXIL with appropriate extensions or shader models.
The implementation is somewhat involved, so I will try to explain the pieces here.
Standard Library
================
The changes to the Slang standard library in `hlsl.meta.slang` are pretty simple. We add new `Load<T>` and `Store<T>` generic methods to `*ByteAddressBuffer`, and route them through to a new IR opcode.
Right now the generic `Load<T>` and `Store<T>` do *not* place any constraints on the type `T`, although in practice they should only work when `T` is a fixed-size type that only contains "first class"
uniform/ordinary data (so no resources, unless the target makes resource types first class). Our front-end checking cannot currently represent first-class-ness and validate it (nor can it represent fixed-size-ness), so these gaps will have to do for now.
Rather than directly translate `Load<T>` or `Store<T>` calls into a single instruction, we instead bottleneck them through internal-use-only subroutines. The design choice here is intended to ensure that for some large user-defined type like `MassiveMaterialStruct` we only emit code for loading all of its fields *once* in the output HLSL/GLSL rather than once per load site. While downstream compilers are likely to inline all of this logic anyway, we are doing what we can to avoid generating bloated code.
Emit and C++/CUDA
=================
Over in `slang-emit-c-like.cpp` we translate the new ops into output code in a straightforward way. A call like `obj.Load<Foo>(offset)` will eventually output as a call like `obj.Load<Foo>(offset)` in the generated code, by default.
For the CPU C++ and CUDA C++ codegen paths, this is enough to make a workable implementation, and we add suitable templated `Load<T>` and `Store<T>` declarations to the prelude for those targets.
Legalization
============
For targets like DXBC and GLSL there is no way to emit a load operation for an aggregate type like a `struct`, so we introduce a legalization pass on the IR that will translate our byte-address-buffer load/store ops into multiple ops that are legal for the target.
Scalarization
-------------
The big picture here is easy enough to understand: when we see a load of a `struct` type from a byte-address buffer, we translate that into loads for each of the fields, and then assemble a new `struct` value from the results. We do similar things for arrays, matrices, and optionally for vectors (depending on the target).
Bit Casting
-----------
After scalarization alone, we might have a load of a `float` or a `float3` that isn't legal for D3D11/DXBC, but that *would* be legal if we just loaded a `uint` or `uint3` and then bit-casted it. The legalization pass thus includes an option to allow for loads/stores to be translated to operate on a same-size unsigned integer type and then to bit-cast.
To make this work actually usable, I had to add some more details to the implementation of the bit-cast op during HLSL emit and, more importantly, I had to customize the way that the byte-address buffer load/store ops get emitted to HLSL so that it prefers to use the existing operations like `Load`/`Load2`/`Load3`/`Load4` instead of the generic one, whenever operating on `uint`s or vectors of `uint`.
Translation to Structured Buffers
---------------------------------
Even after scalarizing all byte-address-buffer loads/stores, we still have a problem for GLSL targets, because a single global `buffer` declaration used to back a byte-address buffer can only have a single element type (currently always `uint`), so the granularity of loads/stores it can express is fixed at declaration time. If we want to load a `half` from a byte-address buffer, we need a dedicated `buffer` declaration in the output GLSL with an element type of `half`.
The solution we employ here is to translate all byte-address buffer loads into "equivalent" structured-buffer ops when targetting GLSL. We add logic to find the underlying global shader parameter that was used for a load/store and introduce a new structured-buffer parameter with the desired element type (e.g., `half`) and then rewrite the load/store op to use that buffer instead. We copy layout information from the original buffer to the new one, so that in the output GLSL all the various `buffer`s will use a single `binding` and thus alias "for free."
We don't want to create a new global buffer for every load/store, so we try to cache these "equivalent" structured buffers as best as we can. For the caching I ended up needing a pair to use as a key, so I tweaked the `KeyValuePair<K,V>` type in `core` so that it could actually work for that purpose.
Because we are working at the level of IR instructions instead of stdlib functions at this work I had to add new IR opcodes to represent structured-buffer load/store that only (currently) apply to GLSL.
Layout
======
In order to translate a load/store of a `struct` type into per-field load/store we need a way to access layout information for the types of the fields. Previously layout information has been an AST-level concern that then gets passed down to the IR only when needed and only on global parameters, so layout information isn't always available in cases like this, at the actual load/store point.
As an expedient move for now I've introduced a dedicated module that does IR-level layout and caches its results on the IR types themselves. This approach *only* supports the "natural" layout of a type, and thus is usable for structured buffers and byte-address buffers (or general pointer load/store on targets that support it), but which is *not* usable for things like constant buffer layout.
We've known for a while that the Right Way to do layout going forward is to have an IR-based layout system, and this could either be seen as a first step toward it, or else as a gross short-term hack. YMMV.
Details
=======
The GLSL "extension tracker" stuff around type support needed to be tweaked to recognize that types like `int16_t` aren't actually available by default. I switched it from using a "black list" of unavailable types at initialization time over to using a "white list" of types that are known to always be available without any extensions.
Tests
=====
There are two tests checked in here: one for the basic case of a `struct` type that has fields that should all be natively loadable, and one that stresses 16-bit types. Each test uses both load and store operations.
Future Directions
=================
Right now we translate vector load/store to GLSL as load/store of individual scalars, which means the assumed alignment is just that of the scalars (consistent with HLSL byte-address buffer rules). We could conceivably introduce some controls to allow outputting the vector load/store ops more directly to GLSL (e.g., declaring a `buffer` of `float4`s), which might enable more efficient load/store based on the alignment rules for `buffer`s.
The IR layout work has a number of rough edges, but the most worrying is probably the assumption that all matrices are laid out in row-major order. Slang really needs an overhaul of its handling of matrices and matrix layout, so I don't know if we can do much better in the near term.
At some point the IR-based layout system needs to be reconciled with our current AST-base layout, and we need to figure out how "natural" layout and the currently computed layouts co-exist (in particular, we need to make sure that the IR-based layout and the existing layout logic for structured buffers will agree). This probably needs to come along once we have moved the core layout logic to operate on IR types instead of AST types (a change we keep talking about).
As part of this work I had to touch the implementation of bit-casting for HLSL, and it seems like that logic has some serious gaps. We really ought to consider a separate legalization pass that can turn IR bitcast instructions into the separate ops that a target actually supports so that we can implement `uint64_t`<->`double` and other conersions that are technically achievable, but which are hard to express in HLSL today.
* fixup: missing files
|
|
* Fix typo in stdlib around WaveGetLaneIndex and WaveGetLaneCount
* Reorder emit so #extensions come before layout
* Added wave-get-lane-index.slang test.
|
|
The only big catch that I ran into with this batch was that I found the `float.getPi()` function was being emitted to the output GLSL even when that function wasn't being used. This seems to have been a latent problem in the earlier PR, but was only surfaced in the tests once a Slang->GLSL test started using another intrinsic that led to the `float : __BuiltinFloatingPointType` witness table being live in the IR.
The fix for the gotcha here was to add a late IR pass that basically empties out all witness tables in the IR, so that functions that are only referenced by witness tables can then be removed as dead code. This pass is something we should *not* apply if/when we start supporting real dynamic dispatch through witness tables, but that is a problem to be solved on another day.
The remaining tricky pieces of this change were:
* Needed to remember to mark functions as target intrinsics on HLSL and/or GLSL as appropriate (hopefully I caught all the cases) so they don't get emitted as source there.
* The `msad4` function in HLSL is very poorly documented, so filling in its definition was tricky. I made my best effort based on how it is described on MSDN, but it is likely that if anybody wants to rely on this function they will need us to vet our results with some tests.
|
|
* WIP add support for __spirv_version .
* Added IRRequireSPIRVVersionDecoration
* SPIR-V version passed to glslang.
Enable VK wave tests.
Split ExtensionTracker out, so can be cast and used externally to emit.
Added SourceResult.
* Fix warning on Clang.
* Missing hlsl.meta.h
* Refactor communication/parsing of __spirv_version with glslang.
* Fix some debug typos.
Be more precise in handling of substring handling.
* Make glslang forwards and backwards binary compatible.
* Small comment improvements.
* Added slang-spirv-target-info.h/cpp
* Fix for major/minor on gcc.
* Another fix for gcc/clang.
* VS projects include slang-spirv-target-info.h/cpp
* Removed SPIRVTargetInfo
Added SemanticVersion.
Don't bother with passing a target to glslang. Should be separate from 'version'.
* Renamed slang-emit-glsl-extension-tracker.cpp/.h -> slang-glsl-extension-tracker.cpp/.h
Fixed some VS project issues.
* Fix a comment.
* Added slang-semantic-version.cpp/.h
* Added slang-glsl-extension-tracker.cpp/.h
* Added split that can check for input has all been parsed.
* Fix problem on x86 win build.
|
|
* Added support for Targets to TypeTextUtil.
* Made Function names 'get' and 'find' instead of 'as' in TypeTextUtil.
|
|
When using row-major layout (via command-line or API option), the following sort of declaration:
```hlsl
StructuredBuffer<float4x4> gBuffer;
... gBuffer[i] ...
```
Generates unexpected results when compiled to DXBC via fxc or DXIL via dxc, because the fxc/dxc compilers do not respect the matrix layout mode in this specific case (a structured buffer of matrices). Instead, they always use column-major layout, even if row-major was requested by the user.
A user can work around this behavior by wrapping the matrix in a `struct`:
```hlsl
struct Wrapper { float4x4 wrapped; }
SturcturedBuffer<Wrapper> gBuffer;
... gBuffer[i].wrapped ...
```
This change simply automates that workaround when compiling for an HLSL-based downstream compiler, so that we get the same behavior across all our backends.
The change adds a test case to confirm the behavior across multiple targets, but it turns out we also had a test checked in that confirmed the buggy (or at least surprising) fxc/dxc behavior, so that one had its baselines changed and can work as a regression test for this fix as well.
|
|
* When using setUniform clamp the amount of data written to the buffer size.
* CUDA implement StructuredBuffer/ByteAddressBuffer as pointer/count as is on CPU.
Allow bounds check to zero index.
Update docs.
* Synthesize tests.
* Fix bug in CUDA output.
* Fixing more tests to run on CUDA.
* Added BaseType for layout of Vector and Matrix - as they are held as int32_t vector array types.
* Enable unbound array support on CUDA.
* Added unsized array support for CUDA documentation.
|
|
* WIP use IRTypeSet in CPPSourceEmitter - doesn't work because of a cloning issue, causing a crash on exit.
* Fix destruction of module issue for IRTypeSet usage in CPPEmitter.
* Fix out definition emitting ordering that was removed.
* Disable cuda output test.
|
|
* 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.
* WIP: CUDA code generation - currently just using CPU layout and HLSL.
* emitXXXForEntryPoint -> emitEntryPointSource
emitSourceForEntryPoint -> emitEntryPointSourceFromIR
Fix up generating cuda to get PTX.
* WIP emitting cuda for IR.
* Small improvements to CUDA ouput.
* Disable the CUDA emit test, as output not currently compilable.
|
|
* 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.
|
|
* 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.
|
|
* 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 setting downstream compiler.
* Setting default downstream compiler for a source type.
|
|
* Initial work on direct emission of SPIR-V
This change adds a first vertical slice of support for emitting SPIR-V code directly from the Slang IR, instead of generating it indirectly via GLSL.
This work isn't usable for anything valuable right now; the goal is just to get something checked in that we can incrementally extend over time.
When invoking `slangc`, the `-emit-spirv-directly` option can be used to turn on the new code path.
I have not bothered to add an equivalent API option, because this flag is only intended to be used for testing in the immediate future.
The existing `emitEntryPoint()` function has become `emitEntryPointSource()` to more accurately reflect its role in a world where we can also emit entry points to a binary format.
Much of the logic that was inside `emitEntryPoint()` had to do with linking and then optimizing/transforming Slang IR code to get it ready for emission on a particular target.
This logic has been factored into a new `linkAndOptimizeIR()` function that can be shared between the path that emits source and the new one that emits SPIR-V.
The meat of the change is then the `emitSPIRVFromIR()` function in `slang-emit-spirv.cpp`, which is called *after* all the optimizations and transformations have been applied to the Slang IR to get it ready.
Rather than repeat myself here, I will try to make the comments in `slang-emit-spirv.cpp` usable as documentation of the approach being taken.
Smaller notes:
* I've included a test case that compares `slangc` output directly to expected SPIR-V. This is perhaps not an ideal plan for how to test SPIR-V emission going forward, but it suffices for now.
* The `external/` directory needed to be added to the include dirs for the `slang` project so that the new code can depend on the SPIR-V header.
* In `slang-ir-link`, the direct SPIR-V generation path means that we now link with a target of SPIR-V instead of GLSL. In principle this can be used to ensure that appropriate variants of intrinsics are selected based on the knowledge that we are emitting SPIR-V. In practice, that isn't being used at all.
* Fixup: path for SPIR-V headers
While working on this PR I used a copy of `spirv.h` that I placed into the repository tree manually, but since I started the work we ended up with SPIR-V headers in our tree anyway, albeit at a different path.
This change tries to fix things up so that my code uses the headers that were already placed in the repository.
* fixup; 64-bit build issue
* fixup: typo fixes based on review
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* If obfuscate is enabled do strip on Layout
* Add option to keep insts that have layout decoration (else DCE strips layout)
* Add NameHint back in lowering - as strip now correctly removes. We may want NameHints in some stages even with obfuscation (for error messages in IR passes), as long as they are removed appropriately at the end
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* 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.
* * Put obfuscateCode on linkage
* Remove obfuscation from variable names - as can be achieved by either stripping and/or removing NameHintDecorations at lowering
* Remove name hints being added during lowering
* Add stripping of SourceLoc location in strip phase
* Hashing of linkage import/export names.
* Do final strip in emitEntryPoint, removes any remaining SourceLoc.
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* Strip IR after front-end steps are done
The main feature of this change is to unconditonally strip out the `IRHighLevelDeclDecoration`s in an IR module once the "mandatory" IR passes in the front end have run. This ensures that later IR passes (e.g., code emission) *cannot* rely on AST-level information to get their job done.
Since I was already writing a pass to remove some instructions at the end of the front-end passes, I went ahead and also made the `-obfuscate` flag apply to the front-end IR generation by causing it to strip `IRNameHintDecoration`s while it is doing the other stripping. With this, the main identifying information left in IR modules (other than semantics and entry-point names) is mangled name strings for imported/exported symbols.
A few other things got changes along the way:
* Removed the `.expected` file for one of the tests, where that file seemingly shouldn't have been checked in at all.
* Updated the signature of the DCE pass both so that it doesn't require a back-end compile request (it wasn't using it anyway), and so that it takes some options to decide whether to keep symbols marked `[export(...)]` alive (the front-end wants to keep these, while back-end passes currently need to be able to eliminate them).
* Moved the `obfuscateCode` flag from the back-end compile request to the base class shared between front- and back-end requests, and updated the options and repro logic to set both as needed. An obvious improvement in the future would be to have the front- and back-end requests share these settings by referencing a single common object in the end-to-end case, rather than each having their own copy.
* Removed logic that was keeping layout instructions alive in DCE, even if they weren't used. This seems to have been a vestige of an intermediate step between AST and IR layout.
* fixup: add the new files
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* 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
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* 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.
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* 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.
* Better handling of swizzling - allow swizzling a scalar into a vector.
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* 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
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This change adds back a little bit of explicit support for global constants in the IR, after a previous change completely removed the existing `IRGlobalConstant` node type.
The new `IRGlobalConstant` is *not* a parent instruction, and doesn't function at all like the old one.
Instead it is effectively a simple instruction that takes zero or one operands:
* The zero-operand case represents a constant with unknown value. This would usually come from another module, and thus would have an `[import(...)]` linkage decoration, so that after linking it resolves to a constant with a known value.
* In the one-operand case, the single operand represents the value of the constant, so that the operation semantically behaves like an identity function. It exists just to give decorations something to "attach" to, so that a global constant with a value can have, e.g., an `[export(...)]` decoration to establish linkage.
The IR lowering pass was updated to create the new node type to wrap any global constants. For now we do this both for global `static const` variables and function-scope `static const`, although the latter doesn't really need the extra indirection.
The IR linking logic was extended to handle linking of global constants akin to how other global instructions are handled. The new logic is mostly boilerplate, and it is likely that a refactor of the linking logic would eliminate the need for this kind of per-instruction-opcode handling of IR instructions that can have linkage.
A custom pass was added that is intended to be run right after linking (it could arguably be folded into `linkIR()`, but I thought it was safer to keep each pass as small as possible). This pass replaces any `IRGlobalConstant` that has a value (operand) with that value, so that global constants should be eliminated after the linking step. This ensures that downstream optimization/transformation passes don't have to deal with the possibility of global constants.
Almost all the existing passes would Just Work if global constants were left in the IR. The two big exceptions are:
* Anything that relies on testing `IRInst*` identity as a way to test for things having the same value would break, since a global constant is a distinct `IRInst*` from its value.
* The type legalization pass doesn't handle `IRGlobalConstant` instructions with non-simple types. This could be added if we ever wanted it, but it seemed silly to write this code now if it would always be dead (and thus untested).
I went ahead and updated the emit logic to handle an `IRGlobalConstant`s that still existing in the IR module at emit time, since the amount of code required was small so that being robust to that case seemed safest (e.g., in case we ever want to have a path that emits code directly while skipping some/all of our IR transformation passes).
There should be no visible changes to the functionality of the compiler with this change, but it should help make IR dumps from the front-end more clear/explicit (since each constant will be a distinct instruction with its own name), and paves the way for supporting proper cross-module linkage of constants.
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