[SYCL][HIP] Simplify ROCm path CMake variables (#6406)

Use a single CMake variable for the root of the ROCm installation rather
than three for the hip include directory, the hip library and the hsa
include directories.

And add a clear CMake error when the ROCm installation doesn't exist.

This was discussed a little while back in #6145 and should make working with non-standard ROCm installation easier and clearer.

Author: npmiller

sycl/doc/GetStartedGuide.md

@@ -231,6 +231,16 @@ Enabling this flag requires an installation of
 ROCm on the system, for instruction on how to install this refer to
 [AMD ROCm Installation Guide for Linux](https://rocmdocs.amd.com/en/latest/Installation_Guide/Installation-Guide.html).
 
+The DPC++ build assumes that ROCm is installed in `/opt/rocm`, if it
+is installed somewhere else, the directory must be provided through
+the CMake variable `SYCL_BUILD_PI_HIP_ROCM_DIR` which can be passed
+using the `--cmake-opt` option of `configure.py` as follows:
+
+```
+python $DPCPP_HOME/llvm/buildbot/configure.py --hip \
+  --cmake-opt=-DSYCL_BUILD_PI_HIP_ROCM_DIR=/usr/local/rocm
+```
+
 Currently, this has only been tried on Linux, with ROCm 4.2.0 or 4.3.0 and
 using the MI50 (gfx906) and MI100 (gfx908) devices.
 
@@ -240,26 +250,6 @@ produce a standard ELF shared code object which can be loaded and executed on an
 The LLD project is enabled by default when configuring for HIP. For more details
 on building LLD refer to [LLD Build Guide](https://lld.llvm.org/).
 
-The following CMake variables can be updated to change where CMake is looking
-for the HIP installation:
-
-* `SYCL_BUILD_PI_HIP_INCLUDE_DIR`: Path to HIP include directory (default
-  `/opt/rocm/hip/include`).
-* `SYCL_BUILD_PI_HIP_HSA_INCLUDE_DIR`: Path to HSA include directory (default
-  `/opt/rocm/hsa/include`).
-* `SYCL_BUILD_PI_HIP_AMD_LIBRARY`: Path to HIP runtime library (default
-  `/opt/rocm/hip/lib/libamdhip64.so`).
-
-These variables can be passed to `configure.py` using `--cmake-opt`, for example
-with a ROCm installation in `/usr/local`:
-
-```
-python $DPCPP_HOME/llvm/buildbot/configure.py --hip \
-  --cmake-opt=-DSYCL_BUILD_PI_HIP_INCLUDE_DIR=/usr/local/rocm/hip/include \
-  --cmake-opt=-DSYCL_BUILD_PI_HIP_HSA_INCLUDE_DIR=/usr/local/rocm/hsa/include \
-  --cmake-opt=-DSYCL_BUILD_PI_HIP_AMD_LIBRARY=/usr/local/rocm/hip/lib/libamdhip64.so
-```
-
 ### Build DPC++ toolchain with support for HIP NVIDIA
 
 There is experimental support for DPC++ for HIP on Nvidia devices. Note as this

sycl/plugins/hip/CMakeLists.txt

@@ -4,10 +4,16 @@ set(SYCL_BUILD_PI_HIP_PLATFORM "AMD" CACHE STRING "PI HIP platform, AMD or NVIDI
 
 message(STATUS "Including the PI API HIP backend for ${SYCL_BUILD_PI_HIP_PLATFORM}.")
 
-# Set default HIP include dirs
-set(SYCL_BUILD_PI_HIP_INCLUDE_DIR "/opt/rocm/hip/include" CACHE STRING "HIP include dir")
-set(SYCL_BUILD_PI_HIP_HSA_INCLUDE_DIR "/opt/rocm/hsa/include" CACHE STRING "HSA include dir")
-set(HIP_HEADERS "${SYCL_BUILD_PI_HIP_INCLUDE_DIR};${SYCL_BUILD_PI_HIP_HSA_INCLUDE_DIR}")
+# Set default ROCm installation directory
+set(SYCL_BUILD_PI_HIP_ROCM_DIR "/opt/rocm" CACHE STRING "ROCm installation dir")
+
+if(NOT EXISTS "${SYCL_BUILD_PI_HIP_ROCM_DIR}")
+  message(FATAL_ERROR "Couldn't find ROCm installation in '${SYCL_BUILD_PI_HIP_ROCM_DIR}',"
+                      " please set SYCL_BUILD_PI_HIP_ROCM_DIR to the path of the ROCm installation.")
+endif()
+
+# Set HIP include dirs
+set(HIP_HEADERS "${SYCL_BUILD_PI_HIP_ROCM_DIR}/hip/include;${SYCL_BUILD_PI_HIP_ROCM_DIR}/hsa/include")
 
 # Create pi_hip library
 add_sycl_plugin(hip
@@ -23,12 +29,11 @@ set_target_properties(pi_hip PROPERTIES LINKER_LANGUAGE CXX)
 
 if("${SYCL_BUILD_PI_HIP_PLATFORM}" STREQUAL "AMD")
   # Import HIP runtime library
-  set(SYCL_BUILD_PI_HIP_AMD_LIBRARY "/opt/rocm/hip/lib/libamdhip64.so" CACHE STRING "HIP AMD runtime library")
   add_library(rocmdrv SHARED IMPORTED GLOBAL)
 
   set_target_properties(
     rocmdrv PROPERTIES
-      IMPORTED_LOCATION                    ${SYCL_BUILD_PI_HIP_AMD_LIBRARY}
+      IMPORTED_LOCATION                    "${SYCL_BUILD_PI_HIP_ROCM_DIR}/hip/lib/libamdhip64.so"
       INTERFACE_INCLUDE_DIRECTORIES        "${HIP_HEADERS}"
       INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "${HIP_HEADERS}"
   )