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

[Matt Arsenault via cfe-commits]

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@@ -0,0 +1,77 @@
+//===- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#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;
+
+    SmallVector<char> Path(Begin->path().begin(), Begin->path().end());
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arsenm wrote:

SmallString? I would also expect to not need the explicit begin/end and use the range constructor 

https://github.com/llvm/llvm-project/pull/116651