[llvm] Add option to dump IR to files instead of stderr (PR #66412)

[Arthur Eubanks via llvm-commits]

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@@ -697,17 +754,42 @@ PrintIRInstrumentation::popModuleDesc(StringRef PassID) {
   return ModuleDesc;
 }
 
+// Callers are responsible for closing the returned file descriptor
+static int prepareDumpIRFileDescriptor(StringRef DumpIRFilename) {
+  std::error_code EC;
+  auto ParentPath = llvm::sys::path::parent_path(DumpIRFilename);
+  if (!ParentPath.empty()) {
+    std::error_code EC = llvm::sys::fs::create_directories(ParentPath);
+    if (EC)
+      report_fatal_error(Twine("Failed to create directory ") + ParentPath +
+                         " to support -ir-dump-directory: " + EC.message());
+  }
+  int Result = 0;
+  EC =
+      sys::fs::openFile(DumpIRFilename, Result, sys::fs::CD_OpenAlways,
+                        sys::fs::FA_Write | sys::fs::FA_Read, sys::fs::OF_None);
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aeubanks wrote:

use `openFileForWrite()` instead?

https://github.com/llvm/llvm-project/pull/66412