[BasicBlockSections] Introduce the basic block sections profile version 1.

[rlavaee]

This patch introduces a new version for the basic block sections profile as was requested in D158442, while keeping backward compatibility for the old version.

The new encoding is as follows:

m <module_name>
f <function_name_1> <function_name_2>...
c <bb_id_1> <bb_id_2> <bb_id_3>
c <bb_id_4> <bb_id_5>
...

Module name specifier (starting with 'm') is optional and allows distinguishing profiles for internal-linkage functions with the same name. If not specified, profile will be applied to any function with the same name.
Function name specifier (starting with 'f') can specify multiple function name aliases.
Finally, basic block clusters are specified by 'c' and specify the cluster of basic blocks, and the internal order in which they must be placed in the same section.

[shenhanc78]

f <function name 1> <function name 2>
So func name 1 and func name 2 are aliaes, right?

[rlavaee]

f <function name 1> <function name 2> So func name 1 and func name 2 are aliaes, right?

Correct. Fixed the function comment.

Sorry. Fixed the pr. Still learning...

[rlavaee]

ping. @tmsri

[rlavaee]

Another friendly ping for review.

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 46d5d264fc66a017bbd0182b2b5fcc0f3f23d3be 8a1893b39119166b6de06c1d182b967015518c3c -- llvm/include/llvm/CodeGen/BasicBlockSectionsProfileReader.h llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp

View the diff from clang-format here.

diff --git a/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp b/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp
index 30f0cbd25316..ef5f1251f532 100644
--- a/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp
+++ b/llvm/lib/CodeGen/BasicBlockSectionsProfileReader.cpp
@@ -86,14 +86,14 @@ Error BasicBlockSectionsProfileReader::ReadV1Profile() {
     switch (Specifier) {
     case '@':
       break;
-    case 'm':  // Module name speicifer.
+    case 'm': // Module name speicifer.
       if (Values.size() != 1) {
         return createProfileParseError(Twine("invalid module name value: '") +
                                        S + "'");
       }
       DIFilename = sys::path::remove_leading_dotslash(Values[0]);
       continue;
-    case 'f': {  // Function names specifier.
+    case 'f': { // Function names specifier.
       bool FunctionFound = any_of(Values, [&](StringRef Alias) {
         auto It = FunctionNameToDIFilename.find(Alias);
         // No match if this function name is not found in this module.
@@ -129,7 +129,7 @@ Error BasicBlockSectionsProfileReader::ReadV1Profile() {
       DIFilename = "";
       continue;
     }
-    case 'c':  // Basic block cluster specifier.
+    case 'c': // Basic block cluster specifier.
       // Skip the profile when we the profile iterator (FI) refers to the
       // past-the-end element.
       if (FI == ProgramBBClusterInfo.end())