[AMDGPU][COMGR] Remove COMGR hotswap HSA tool

amd/comgr/src/hotswap/CMakeLists.txt

@@ -52,35 +52,3 @@ target_link_libraries(hotswap-transpiler
     LLVMSupport
     LLVMTargetParser
 )
-
-# HSA_TOOLS_LIB hotswap tool (libamd_comgr_hotswap_tool.so): ROCR loads it via
-# HSA_TOOLS_LIB and it rewrites code objects through the comgr hotswap API.
-# Off by default - it is an opt-in artifact most comgr consumers do not need.
-# When enabled it requires the HSA headers (inc/hsa.h, from
-# HOTSWAP_TOOL_HSA_INCLUDE_ROOT); configuration errors if they are not found.
-option(HOTSWAP_BUILD_TOOL "Build the HSA_TOOLS_LIB hotswap tool" OFF)
-if(HOTSWAP_BUILD_TOOL)
-  if(NOT CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    message(FATAL_ERROR
-      "HOTSWAP_BUILD_TOOL is only supported on Linux (it requires the HSA "
-      "runtime); set HOTSWAP_BUILD_TOOL=OFF on this platform.")
-  endif()
-  find_path(HOTSWAP_TOOL_HSA_INC inc/hsa.h HINTS "${HOTSWAP_TOOL_HSA_INCLUDE_ROOT}")
-  if(NOT HOTSWAP_TOOL_HSA_INC)
-    message(FATAL_ERROR
-      "HOTSWAP_BUILD_TOOL is ON but inc/hsa.h was not found. Set "
-      "HOTSWAP_TOOL_HSA_INCLUDE_ROOT to the rocr-runtime hsa-runtime directory, "
-      "or set HOTSWAP_BUILD_TOOL=OFF.")
-  endif()
-  # amd/comgr/src/hotswap binary dir -> amd/comgr binary dir (generated amd_comgr.h).
-  get_filename_component(_comgr_bin "${CMAKE_CURRENT_BINARY_DIR}/../.." ABSOLUTE)
-  add_library(amd_comgr_hotswap_tool SHARED comgr-hotswap-tool.cpp)
-  set_target_properties(amd_comgr_hotswap_tool PROPERTIES
-    CXX_STANDARD 17 CXX_STANDARD_REQUIRED ON POSITION_INDEPENDENT_CODE ON)
-  target_include_directories(amd_comgr_hotswap_tool PRIVATE
-    "${HOTSWAP_TOOL_HSA_INC}"
-    "${_comgr_bin}/include")  # generated amd_comgr.h
-  target_link_libraries(amd_comgr_hotswap_tool PRIVATE amd_comgr)
-  install(TARGETS amd_comgr_hotswap_tool
-    LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT amd-comgr)
-endif()

amd/comgr/src/hotswap/README.md

@@ -1,78 +1,14 @@
 # HotSwap
 
-HotSwap rewrites AMDGPU code objects at load time so that a binary built for one
-gfx1250 stepping runs correctly on another. The `amd_comgr_hotswap_rewrite` API
-applies a small set of stepping-specific patches in place, without recompiling
-the code object.
-
-This directory ships two things:
-
-- The comgr hotswap tool (`libamd_comgr_hotswap_tool.so`), loaded via the
-  `HSA_TOOLS_LIB` env var, which applies the rewrite automatically at runtime.
-- The transpiler, a raiser-based path for the heavier cross-ISA case. It is
-  documented at the bottom of this file.
-
-The tool is Linux only: it requires the HSA runtime, so the build errors on
-other platforms.
-
-## Running with the tool
-
-Point `HSA_TOOLS_LIB` at the tool and run any HIP or HSA application unchanged:
-
-```bash
-HSA_TOOLS_LIB=/opt/rocm/lib/libamd_comgr_hotswap_tool.so ./my_app
-```
-
-`HSA_TOOLS_LIB` tells the `libhsa-runtime` what tool to hand each code object it encounters to before dispatch. When the tool detects a gfx1250 A0 board, it rewrites every gfx1250 code object in place via `amd_comgr_hotswap_rewrite`. Everything else passes through untouched.
-
-If a rewrite fails, the tool logs the failure and forwards the original code
-object. The application still runs, just without the rewrite applied.
-
-## Supported architectures
-
-| Architecture        | Status      |
-| ------------------- | ----------- |
-| gfx1250, ASIC rev A0 | Rewrite armed |
-| gfx950              | Coming soon |
-| gfx942              | Coming soon |
-
-HotSwap currently requires a homogeneous GPU setup. Running it across multiple
-GPUs is not supported.
-
-The tool detects the device on its own. It reads the agent ISA name and
-`HSA_AMD_AGENT_INFO_ASIC_REVISION`, then arms the rewrite only when the target
-is gfx1250, the revision is 0 (A0), and the revision query succeeded. A failed
-query is never treated as A0. On any other device or revision, code objects pass
-through unchanged. No environment variable is needed to turn this on.
-
-To confirm the rewrite is active, set `HSA_HOTSWAP_TOOL_VERBOSE=1` and look for
-this line in the logs:
-
-```bash
-hotswap_tool: device=gfx1250 asic_revision=0 -> A0 (rewrite armed)
-```
-
-## Environment variables
-
-| Variable                   | Effect                                                        |
-| -------------------------- | ------------------------------------------------------------- |
-| `HSA_TOOLS_LIB`            | Standard HSA hook. Set it to this `.so` to load the tool.     |
-| `HSA_HOTSWAP_TOOL_VERBOSE` | Set to `1` for diagnostic logging to stderr, covering device detection and per-code-object rewrite results. Logging only; does not change behavior. Off by default. |
-
-## Building the tool
-
-The tool is off by default, since most comgr consumers do not need it. Enable it
-and point the build at the HSA headers:
-
-```bash
-cmake -S amd/comgr -B build \
-  -DHOTSWAP_BUILD_TOOL=ON \
-  -DHOTSWAP_TOOL_HSA_INCLUDE_ROOT=/path/to/rocr-runtime/runtime/hsa-runtime
-ninja -C build amd_comgr_hotswap_tool
-```
-
-If `HOTSWAP_BUILD_TOOL` is on but `inc/hsa.h` cannot be found under
-`HOTSWAP_TOOL_HSA_INCLUDE_ROOT`, the build fails.
+HotSwap is COMGR's AMDGPU code-object rewriting support. The public
+`amd_comgr_hotswap_rewrite` API takes an executable code object plus source and
+target ISA names, then returns a new executable code object with the applicable
+rewrite applied. The input code object is not modified.
+
+This directory contains COMGR's hotswap transpiler scaffolding, the raiser-based
+path for heavier cross-ISA transformations. The same-family stepping patches are
+implemented in the surrounding COMGR source files and are exposed through
+`amd_comgr_hotswap_rewrite`.
 
 ## Transpiler (cross-gen)