[llvm] [llvm-profgen] Loading binary functions from .symtab when DWARF info is incomplete (PR #163654)

[Lei Wang via llvm-commits]

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@@ -65,6 +65,13 @@ static cl::list<std::string> DisassembleFunctions(
              "names only. Only work with show-disassembly-only"),
     cl::cat(ProfGenCategory));
 
+static cl::opt<bool>
+    LoadFunctionFromSymbol("load-function-from-symbol", cl::init(true),
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wlei-llvm wrote:

Yeah, iirc, we initially only loaded the function ranges from symbol table, then after we found the issue with the multi-version function(foo.cold, foo.resume...), we redesigned and fully switched to load the symbol from dwarf. 

At that time,  the code was implemented inside the `dissassembleSymbol`(which also iterates the symbols),  
https://github.com/llvm/llvm-project/blob/main/llvm/tools/llvm-profgen/ProfiledBinary.cpp#L529



https://github.com/llvm/llvm-project/pull/163654