[clang] [flang] Add IR Profile-Guided Optimization (IR PGO) support to the Flang compiler (PR #136098)

[Tom Eccles via cfe-commits]

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@@ -148,6 +148,55 @@ class CodeGenOptions : public CodeGenOptionsBase {
   /// OpenMP is enabled.
   using DoConcurrentMappingKind = flangomp::DoConcurrentMappingKind;
 
+  enum ProfileInstrKind {
+    ProfileNone,       // Profile instrumentation is turned off.
+    ProfileClangInstr, // Clang instrumentation to generate execution counts
+                       // to use with PGO.
+    ProfileIRInstr,    // IR level PGO instrumentation in LLVM.
+    ProfileCSIRInstr, // IR level PGO context sensitive instrumentation in LLVM.
+  };
+
+
+  /// Name of the profile file to use as output for -fprofile-instr-generate,
+  /// -fprofile-generate, and -fcs-profile-generate.
+  std::string InstrProfileOutput;
+
+  /// Name of the profile file to use as input for -fmemory-profile-use.
+  std::string MemoryProfileUsePath;
+
+  unsigned int DebugInfoForProfiling;
+
+  unsigned int AtomicProfileUpdate;
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tblah wrote:

Why are these added here and also in CodeGenOptions.def?

https://github.com/llvm/llvm-project/pull/136098