[llvm] [ctx_prof] Handle case when no root is in this Module. (PR #107463)

[Teresa Johnson via llvm-commits]

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@@ -0,0 +1,60 @@
+; REQUIRES: x86_64-linux
+;
+; RUN: rm -rf %t
+; RUN: split-file %s %t
+; RUN: llvm-ctxprof-util fromJSON --input=%t/profile.json --output=%t/profile.ctxprofdata
+; RUN: opt -passes='require<ctx-prof-analysis>,print<ctx-prof-analysis>' -ctx-profile-printer-level=everything \
+; RUN:   %t/example.ll -S 2>&1 | FileCheck %s
+
+; CHECK: No contextual profile was provided
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teresajohnson wrote:

Should the error be a bit more explicit - e.g. "No contextual profile containing functions from this module was provided" or something like that?

https://github.com/llvm/llvm-project/pull/107463