HIP compilers

HIP compilers#

ROCm provides the compiler tools used to compile HIP applications for use on AMD GPUs. The compilers set up the default libraries and include paths for the HIP and ROCm libraries and some needed environment variables. For more information, see the ROCm compiler reference.

Compilation workflow#

HIP provides a flexible compilation workflow that supports both offline compilation and runtime or just-in-time (JIT) compilation. Each approach has advantages depending on the use case, target architecture, and performance needs.

The offline compilation is ideal for production environments, where the performance is critical and the target GPU architecture is known in advance.

The runtime compilation is useful in development environments or when distributing software that must run on a wide range of hardware without the knowledge of the GPU in advance. It provides flexibility at the cost of some performance overhead.

Offline compilation#

Offline compilation is performed in two steps: host and device code compilation.

  • Host-code compilation: On the host side, amdclang++ or hipcc can compile the host code in one step without other C++ compilers.

  • Device-code compilation: The compiled device code is embedded into the host object file. Depending on the platform, the device code can be compiled into assembly or binary.

For an example on how to compile HIP from the command line, see SAXPY tutorial .

Runtime compilation#

HIP allows you to compile kernels at runtime using the hiprtc* API. Kernels are stored as a text string, which is passed to HIPRTC alongside options to guide the compilation.

For more information, see HIP runtime compiler.

Static libraries#

Both amdclang++ and hipcc support generating two types of static libraries.

  • The first type of static library only exports and launches host functions within the same library and not the device functions. This library type offers the ability to link with another compiler such as gcc. Additionally, this library type contains host objects with device code embedded as fat binaries. This library type is generated using the flag --emit-static-lib:

    amdclang++ hipOptLibrary.cpp --emit-static-lib -fPIC -o libHipOptLibrary.a
gcc test.cpp -L. -lhipOptLibrary -L/path/to/hip/lib -lamdhip64 -o test.out

  • The second type of static library exports device functions to be linked by other code objects by using amdclang++ or hipcc as the linker. This library type contains relocatable device objects and is generated using ar:

    hipcc hipDevice.cpp -c -fgpu-rdc -o hipDevice.o
ar rcsD libHipDevice.a hipDevice.o
hipcc libHipDevice.a test.cpp -fgpu-rdc -o test.out

Examples of this can be found in rocm-examples under static host libraries or static device libraries.

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