[libc-commits] [clang] [compiler-rt] [libc] [llvm] [PGO][AMDGPU] Add offload profiling with uniformity-aware optimization (PR #177665)

[Joseph Huber via libc-commits]

================
@@ -0,0 +1,916 @@
+//===- InstrProfilingPlatformROCm.c - Profile data ROCm platform ---------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "InstrProfiling.h"
+#include "InstrProfilingInternal.h"
+#include "InstrProfilingPort.h"
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* -------------------------------------------------------------------------- */
+/*  Platform abstraction for dynamic library loading                          */
+/* -------------------------------------------------------------------------- */
+
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+typedef HMODULE DylibHandle;
+
+static DylibHandle DylibOpen(const char *Name) { return LoadLibraryA(Name); }
+
+static void *DylibSym(DylibHandle H, const char *Sym) {
+  return (void *)(uintptr_t)GetProcAddress(H, Sym);
+}
+
+static int DylibAvailable(void) { return 1; }
+
+#else /* POSIX */
+#include <dlfcn.h>
+
+/* Use weak references for dl* functions to avoid requiring -ldl at link time.
+ *
+ * The profile runtime is a static library, so its dependencies must be
+ * explicitly linked by the user. Unlike sanitizer runtimes (which are often
+ * shared libraries with their own dependencies), adding -ldl globally would
+ * affect all profiling users, including those not using HIP/ROCm.
+ *
+ * With weak references:
+ * - Programs without -ldl link successfully (dl* resolve to NULL)
+ * - HIP programs get -ldl from the HIP runtime, so dl* work normally
+ * - OpenMP offload programs without HIP gracefully skip device profiling
+ */
+#pragma weak dlopen
+#pragma weak dlsym
+#pragma weak dlerror
+
+typedef void *DylibHandle;
+
+static DylibHandle DylibOpen(const char *Name) {
+  return dlopen(Name, RTLD_LAZY | RTLD_LOCAL);
----------------
jhuber6 wrote:

Does compiler-rt have helpers for all the dynamic libary handling?

https://github.com/llvm/llvm-project/pull/177665