[flang-commits] [lld] [lldb] [clang-tools-extra] [compiler-rt] [flang] [llvm] [clang] [libcxx] [openmp] [libc] [PGO][OpenMP] Instrumentation for GPU devices (PR #76587)

[Joseph Huber via flang-commits]

================
@@ -163,3 +163,87 @@ Error GenericGlobalHandlerTy::readGlobalFromImage(GenericDeviceTy &Device,
 
   return Plugin::success();
 }
+
+bool GenericGlobalHandlerTy::hasProfilingGlobals(GenericDeviceTy &Device,
+                                                 DeviceImageTy &Image) {
+  GlobalTy global(getInstrProfNamesVarName().str(), 0);
+  if (auto Err = getGlobalMetadataFromImage(Device, Image, global)) {
+    consumeError(std::move(Err));
+    return false;
+  }
+  return true;
+}
+
+Expected<GPUProfGlobals>
+GenericGlobalHandlerTy::readProfilingGlobals(GenericDeviceTy &Device,
+                                             DeviceImageTy &Image) {
+  GPUProfGlobals profdata;
+  auto ELFObj = getELFObjectFile(Image);
+  if (!ELFObj)
+    return ELFObj.takeError();
+  profdata.targetTriple = ELFObj->makeTriple();
+  // Iterate through elf symbols
+  for (auto &sym : ELFObj->symbols()) {
+    if (auto name = sym.getName()) {
+      // Check if given current global is a profiling global based
+      // on name
+      if (name->equals(getInstrProfNamesVarName())) {
+        // Read in profiled function names
+        std::vector<char> chars(sym.getSize() / sizeof(char), ' ');
+        GlobalTy NamesGlobal(name->str(), sym.getSize(), chars.data());
----------------
jhuber6 wrote:

Okay, we're reading a string back from the device? What's the purpose of that? Also, just so you know, the ELF will only contain the correct size if it's emitted as an array. E.g.
```
const char a[] = "a"; // strlen("a") + 1 in ELF
const char *b = "b"; // sizeof(char *) in ELF
```

https://github.com/llvm/llvm-project/pull/76587