- C++ 72.1%
- HLSL 12%
- LLVM 8.6%
- C 4.7%
- Python 1.3%
- Other 1%
bacbfaa660Fixes #8306. ## Summary Building DXC with newer Apple toolchains fails in `include/llvm/ADT/StringRef.h` because libc++ now rejects user specializations of certain standard library traits. DXC currently specializes: - `std::is_nothrow_constructible<std::string, llvm::StringRef>` - `std::is_nothrow_constructible<std::string, llvm::StringRef &>` - `std::is_nothrow_constructible<std::string, const llvm::StringRef &>` On Xcode 26.4 / Apple clang 21 / libc++, that now produces an error like: > `is_nothrow_constructible` cannot be specialized: Users are not allowed to specialize this standard library entity ## What this changes This patch keeps the existing HLSL workaround for non-libc++ standard libraries, but disables those `std::is_nothrow_constructible` specializations when building against libc++: ```cpp #if !defined(_LIBCPP_VERSION) ... #endif ``` Why this fixes the issue The failure is caused by the specializations themselves, not by any runtime behavior in StringRef. For libc++: - the specializations are now ill-formed and rejected at parse time - libc++ already computes std::is_nothrow_constructible<std::string, llvm::StringRef> correctly without the workaround So the fix is to stop declaring the forbidden specialization on libc++, while preserving the existing behavior everywhere else. Why I chose this approach I looked at the HLSL-specific block in StringRef.h and tested the current Apple libc++ behavior directly. Without the manual specialization, libc++ still reports the relevant is_nothrow_constructible cases as false, which matches the intent of the original workaround. That made this the narrowest safe fix: - it resolves the Xcode/libc++ build break in #8306 - it does not change runtime code generation or ABI - it preserves the original workaround for non-libc++ environments where it may still be needed Validation I verified: - the original header fails to compile with current Xcode/libc++ - after this change, the header compiles cleanly - on libc++, the relevant std::is_nothrow_constructible instantiations still evaluate to false |
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DirectX Shader Compiler
The DirectX Shader Compiler project includes a compiler and related tools used to compile High-Level Shader Language (HLSL) programs into DirectX Intermediate Language (DXIL) representation. Applications that make use of DirectX for graphics, games, and computation can use it to generate shader programs.
For more information, see the Wiki.
Visit the DirectX Landing Page for more resources for DirectX developers.
Features and Goals
The starting point of the project is a fork of the LLVM and Clang projects, modified to accept HLSL and emit a validated container that can be consumed by GPU drivers.
At the moment, the DirectX HLSL Compiler provides the following components:
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dxc.exe, a command-line tool that can compile HLSL programs for shader model 6.0 or higher
-
dxcompiler.dll, a DLL providing a componentized compiler, assembler, disassembler, and validator
-
dxilconv.dll, a DLL providing a converter from DXBC (older shader bytecode format)
-
dxv.exe, a command-line tool that validates DXIL IR (compiled HLSL programs).
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various other tools based on the above components
The Microsoft Windows SDK releases include a supported version of the compiler and validator.
The goal of the project is to allow the broader community of shader developers to contribute to the language and representation of shader programs, maintaining the principles of compatibility and supportability for the platform. It's currently in active development across two axes: language evolution (with no impact to DXIL representation), and surfacing hardware capabilities (with impact to DXIL, and thus requiring coordination with GPU implementations).
Pre-built Releases
Development kits containing only the dxc.exe driver app, the dxcompiler.dll, and the dxil.dll signing binary are available here, or in the releases tab.
SPIR-V CodeGen
As an example of community contribution, this project can also target the SPIR-V intermediate representation. Please see the doc for how HLSL features are mapped to SPIR-V, and the wiki page for how to build, use, and contribute to the SPIR-V CodeGen.
Metal CodeGen
When built from source DXC can utilize the Metal Shader
Converter if it is
available during build and configuration time. This allows DXC to generate Metal
shader libraries directly using the -metal flag.
Note: DXC cannot currently disassemble Metal shaders so the -Fc flag cannot be
used in conjunction with the -Fo flag.
Building Sources
See the full documentation for Building and testing DXC for detailed instructions.
Running Shaders
To run shaders compiled as DXIL, you will need support from the operating system as well as from the driver for your graphics adapter. Windows 10 Creators Update is the first version to support DXIL shaders. See the Wiki for information on using experimental support or the software adapter.
Hardware Support
Hardware GPU support for DXIL is provided by the following vendors:
NVIDIA
NVIDIA's r396 drivers (r397.64 and later) provide release mode support for DXIL 1.1 and Shader Model 6.1 on Win10 1709 and later, and experimental mode support for DXIL 1.2 and Shader Model 6.2 on Win10 1803 and later. These drivers also support DXR in experimental mode.
Drivers can be downloaded from geforce.com.
AMD
AMD’s driver (Radeon Software Adrenalin Edition 18.4.1 or later) provides release mode support for DXIL 1.1 and Shader Model 6.1. Drivers can be downloaded from AMD's download site.
Intel
Intel's 15.60 drivers (15.60.0.4849 and later) support release mode for DXIL 1.0 and Shader Model 6.0 as well as release mode for DXIL 1.1 and Shader Model 6.1 (View Instancing support only).
Drivers can be downloaded from the following link Intel Graphics Drivers
Direct access to 15.60 driver (latest as of this update) is provided below:
Making Changes
To make contributions, see the CONTRIBUTING.md file in this project.
Documentation
You can find documentation for this project in the docs directory. These contain the original LLVM documentation files, as well as two new files worth nothing:
- HLSLChanges.rst: this is the starting point for how this fork diverges from the original llvm/clang sources
- DXIL.rst: this file contains the specification for the DXIL format
- tools/clang/docs/UsingDxc.rst: this file contains a user guide for dxc.exe
License
DirectX Shader Compiler is distributed under the terms of the University of Illinois Open Source License.
See LICENSE.txt and ThirdPartyNotices.txt for details.
Code of Conduct
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.