[clang] [Driver] Enable -ftime-trace for CUDA/HIP device compilation (PR #179701)

[Joseph Huber via cfe-commits]

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@@ -5858,22 +5858,67 @@ static void handleTimeTrace(Compilation &C, const ArgList &Args,
       Args.getLastArg(options::OPT_ftime_trace, options::OPT_ftime_trace_EQ);
   if (!A)
     return;
+
+  std::string OffloadingPrefix;
+  if (JA->getOffloadingDeviceKind() != Action::OFK_None) {
+    const ToolChain *TC = JA->getOffloadingToolChain();
+    OffloadingPrefix = Action::GetOffloadingFileNamePrefix(
+        JA->getOffloadingDeviceKind(),
+        TC ? TC->getTriple().normalize() : "",
+        /*CreatePrefixForHost=*/false);
+    if (const char *Arch = JA->getOffloadingArch()) {
+      OffloadingPrefix += "-";
+      OffloadingPrefix += Arch;
+    }
+  } else if (JA->getOffloadingHostActiveKinds() != Action::OFK_None &&
+             C.getDriver().isSaveTempsEnabled()) {
+    OffloadingPrefix = Action::GetOffloadingFileNamePrefix(
+        Action::OFK_None,
+        C.getDefaultToolChain().getTriple().normalize(),
+        /*CreatePrefixForHost=*/true);
+  }
+
   SmallString<128> Path;
   if (A->getOption().matches(options::OPT_ftime_trace_EQ)) {
     Path = A->getValue();
     if (llvm::sys::fs::is_directory(Path)) {
-      SmallString<128> Tmp(Result.getFilename());
-      llvm::sys::path::replace_extension(Tmp, "json");
-      llvm::sys::path::append(Path, llvm::sys::path::filename(Tmp));
+      // When -ftime-trace=<dir> and it's a directory:
+      // - For host/non-offload: use the output filename stem
+      // - For offload: use input filename stem + offloading prefix
+      SmallString<128> Tmp;
+      if (OffloadingPrefix.empty()) {
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jhuber6 wrote:

Why does this portion need to be aware of the OffloadingPrefix? Couldn't we just replace the value of `Result` or something?

https://github.com/llvm/llvm-project/pull/179701