[clang] [llvm] [compiler-rt] [clang-tools-extra] [Profile] Allow profile merging with multiple correlate files. (PR #75957)

[Zequan Wu via cfe-commits]

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@@ -118,18 +118,18 @@ cl::opt<std::string> ProfiledBinary(
     "profiled-binary", cl::init(""),
     cl::desc("Path to binary from which the profile was collected."),
     cl::sub(ShowSubcommand), cl::sub(MergeSubcommand));
-cl::opt<std::string> DebugInfoFilename(
-    "debug-info", cl::init(""),
+cl::list<std::string> DebugInfoFilenames(
+    "debug-info",
     cl::desc(
         "For show, read and extract profile metadata from debug info and show "
         "the functions it found. For merge, use the provided debug info to "
         "correlate the raw profile."),
     cl::sub(ShowSubcommand), cl::sub(MergeSubcommand));
-cl::opt<std::string>
-    BinaryFilename("binary-file", cl::init(""),
-                   cl::desc("For merge, use the provided unstripped bianry to "
-                            "correlate the raw profile."),
-                   cl::sub(MergeSubcommand));
+cl::list<std::string>
+    BinaryFilenames("binary-file",
+                    cl::desc("For merge, use the provided unstripped bianry to "
+                             "correlate the raw profile."),
+                    cl::sub(MergeSubcommand));
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ZequanWu wrote:

> It looks like we are switching from passing a single correlation file to a list of correlation files. Is that so that we can pass all raw profiles into a single llvm-profdata merge command?

Yes, that's the purpose. 

> Presumably we should know which binaries produce which raw profiles.

This isn't always the case. When there are shared libraries producing raw profiles and `LLVM_PROFILE_FILE=default-%4m.profraw`, we will get bunch of `default-{hash}.profraw` produced by all shared libraries and main executable. There's no way to differentiate which raw profiles are generated by which binaries. @gulfemsavrun also has use case for this situation: https://discourse.llvm.org/t/rfc-add-binary-profile-correlation-to-not-load-profile-metadata-sections-into-memory-at-runtime/74565/8?u=zequanwu

https://github.com/llvm/llvm-project/pull/75957