[amdgpu-arch] Replace use of HSA with reading sysfs directly (#116651)

Summary:
For Linux systems, we currently use the HSA library to determine the
installed GPUs. However, this isn't really necessary and adds a
dependency on the HSA runtime as well as a lot of overhead. Instead,
this patch uses the `sysfs` interface exposed by `amdkfd` to do this
directly.

Author: jhuber6

clang/tools/amdgpu-arch/AMDGPUArch.cpp

@@ -25,7 +25,7 @@ static void PrintVersion(raw_ostream &OS) {
   OS << clang::getClangToolFullVersion("amdgpu-arch") << '\n';
 }
 
-int printGPUsByHSA();
+int printGPUsByKFD();
 int printGPUsByHIP();
 
 int main(int argc, char *argv[]) {
@@ -45,7 +45,7 @@ int main(int argc, char *argv[]) {
   }
 
 #ifndef _WIN32
-  if (!printGPUsByHSA())
+  if (!printGPUsByKFD())
     return 0;
 #endif
 

clang/tools/amdgpu-arch/AMDGPUArchByHSA.cpp

@@ -0,0 +1,78 @@
+//===- AMDGPUArchByKFD.cpp - list AMDGPU installed ------*- C++ -*---------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a tool for detecting name of AMD GPUs installed in
+// system using the Linux sysfs interface for the AMD KFD driver. This file does
+// not respect ROCR_VISIBLE_DEVICES like the ROCm environment would.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/LineIterator.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+#include <memory>
+#include <string>
+
+using namespace llvm;
+
+constexpr static const char *KFD_SYSFS_NODE_PATH =
+    "/sys/devices/virtual/kfd/kfd/topology/nodes";
+
+// See the ROCm implementation for how this is handled.
+// https://github.com/ROCm/ROCT-Thunk-Interface/blob/master/src/libhsakmt.h#L126
+constexpr static long getMajor(long Ver) { return (Ver / 10000) % 100; }
+constexpr static long getMinor(long Ver) { return (Ver / 100) % 100; }
+constexpr static long getStep(long Ver) { return Ver % 100; }
+
+int printGPUsByKFD() {
+  SmallVector<std::pair<long, long>> Devices;
+  std::error_code EC;
+  for (sys::fs::directory_iterator Begin(KFD_SYSFS_NODE_PATH, EC), End;
+       Begin != End; Begin.increment(EC)) {
+    if (EC)
+      return 1;
+
+    long Node = 0;
+    if (sys::path::stem(Begin->path()).consumeInteger(10, Node))
+      return 1;
+
+    SmallString<0> Path(Begin->path());
+    sys::path::append(Path, "properties");
+
+    ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
+        MemoryBuffer::getFileOrSTDIN(Path);
+    if (std::error_code EC = BufferOrErr.getError())
+      return 1;
+
+    long GFXVersion = 0;
+    for (line_iterator Lines(**BufferOrErr, false); !Lines.is_at_end();
+         ++Lines) {
+      StringRef Line(*Lines);
+      if (Line.consume_front("gfx_target_version")) {
+        Line.drop_while([](char C) { return std::isspace(C); });
+        if (Line.consumeInteger(10, GFXVersion))
+          return 1;
+        break;
+      }
+    }
+
+    // If this is zero the node is a CPU.
+    if (GFXVersion == 0)
+      continue;
+    Devices.emplace_back(Node, GFXVersion);
+  }
+
+  // Sort the devices by their node to make sure it prints in order.
+  llvm::sort(Devices, [](auto &L, auto &R) { return L.first < R.first; });
+  for (const auto &[Node, GFXVersion] : Devices)
+    std::fprintf(stdout, "gfx%ld%ld%lx\n", getMajor(GFXVersion),
+                 getMinor(GFXVersion), getStep(GFXVersion));
+
+  return 0;
+}

clang/tools/amdgpu-arch/AMDGPUArchByKFD.cpp

@@ -8,6 +8,6 @@
 
 set(LLVM_LINK_COMPONENTS Support)
 
-add_clang_tool(amdgpu-arch AMDGPUArch.cpp AMDGPUArchByHSA.cpp AMDGPUArchByHIP.cpp)
+add_clang_tool(amdgpu-arch AMDGPUArch.cpp AMDGPUArchByKFD.cpp AMDGPUArchByHIP.cpp)
 
 target_link_libraries(amdgpu-arch PRIVATE clangBasic)